Merge branch 'master' into next

.gitignore

@@ -49,6 +49,7 @@ include/linux/compile.h
 include/linux/version.h
 include/linux/utsrelease.h
 include/linux/bounds.h
+include/generated
 
 # stgit generated dirs
 patches-*

CREDITS

@@ -495,6 +495,11 @@ S: Kopmansg 2
 S: 411 13  Goteborg
 S: Sweden
 
+N: Paul Bristow
+E: paul@paulbristow.net
+W: http://paulbristow.net/linux/idefloppy.html
+D: Maintainer of IDE/ATAPI floppy driver
+
 N: Dominik Brodowski
 E: linux@brodo.de
 W: http://www.brodo.de/
@@ -1407,8 +1412,8 @@ P: 1024D/77D4FC9B F5C5 1C20 1DFC DEC3 3107  54A4 2332 ADFC 77D4 FC9B
 D: National Language Support
 D: Linux Internationalization Project
 D: German Localization for Linux and GNU software
-S: Kriemhildring 12a
-S: 65795 Hattersheim am Main
+S: Auf der Fittel 18
+S: 53347 Alfter
 S: Germany
 
 N: Christoph Hellwig
@@ -2642,6 +2647,10 @@ S: C/ Mieses 20, 9-B
 S: Valladolid 47009
 S: Spain
 
+N: Gadi Oxman
+E: gadio@netvision.net.il
+D: Original author and maintainer of IDE/ATAPI floppy/tape drivers
+
 N: Greg Page
 E: gpage@sovereign.org
 D: IPX development and support
@@ -3571,6 +3580,12 @@ N: Dirk Verworner
 D: Co-author of German book ``Linux-Kernel-Programmierung''
 D: Co-founder of Berlin Linux User Group
 
+N: Riku Voipio
+E: riku.voipio@iki.fi
+D: Author of PCA9532 LED and Fintek f75375s hwmon driver
+D: Some random ARM board patches
+S: Finland
+
 N: Patrick Volkerding
 E: volkerdi@ftp.cdrom.com
 D: Produced the Slackware distribution, updated the SVGAlib

Documentation/00-INDEX

@@ -86,6 +86,8 @@ cachetlb.txt
 	- describes the cache/TLB flushing interfaces Linux uses.
 cdrom/
 	- directory with information on the CD-ROM drivers that Linux has.
+cgroups/
+	- cgroups features, including cpusets and memory controller.
 connector/
 	- docs on the netlink based userspace<->kernel space communication mod.
 console/
@@ -98,8 +100,6 @@ cpu-load.txt
 	- document describing how CPU load statistics are collected.
 cpuidle/
 	- info on CPU_IDLE, CPU idle state management subsystem.
-cpusets.txt
-	- documents the cpusets feature; assign CPUs and Mem to a set of tasks.
 cputopology.txt
 	- documentation on how CPU topology info is exported via sysfs.
 cris/

Documentation/ABI/testing/debugfs-kmemtrace

@@ -0,0 +1,71 @@
+What:		/sys/kernel/debug/kmemtrace/
+Date:		July 2008
+Contact:	Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
+Description:
+
+In kmemtrace-enabled kernels, the following files are created:
+
+/sys/kernel/debug/kmemtrace/
+	cpu<n>		(0400)	Per-CPU tracing data, see below. (binary)
+	total_overruns	(0400)	Total number of bytes which were dropped from
+				cpu<n> files because of full buffer condition,
+				non-binary. (text)
+	abi_version	(0400)	Kernel's kmemtrace ABI version. (text)
+
+Each per-CPU file should be read according to the relay interface. That is,
+the reader should set affinity to that specific CPU and, as currently done by
+the userspace application (though there are other methods), use poll() with
+an infinite timeout before every read(). Otherwise, erroneous data may be
+read. The binary data has the following _core_ format:
+
+	Event ID	(1 byte)	Unsigned integer, one of:
+		0 - represents an allocation (KMEMTRACE_EVENT_ALLOC)
+		1 - represents a freeing of previously allocated memory
+		    (KMEMTRACE_EVENT_FREE)
+	Type ID		(1 byte)	Unsigned integer, one of:
+		0 - this is a kmalloc() / kfree()
+		1 - this is a kmem_cache_alloc() / kmem_cache_free()
+		2 - this is a __get_free_pages() et al.
+	Event size	(2 bytes)	Unsigned integer representing the
+					size of this event. Used to extend
+					kmemtrace. Discard the bytes you
+					don't know about.
+	Sequence number	(4 bytes)	Signed integer used to reorder data
+					logged on SMP machines. Wraparound
+					must be taken into account, although
+					it is unlikely.
+	Caller address	(8 bytes)	Return address to the caller.
+	Pointer to mem	(8 bytes)	Pointer to target memory area. Can be
+					NULL, but not all such calls might be
+					recorded.
+
+In case of KMEMTRACE_EVENT_ALLOC events, the next fields follow:
+
+	Requested bytes	(8 bytes)	Total number of requested bytes,
+					unsigned, must not be zero.
+	Allocated bytes (8 bytes)	Total number of actually allocated
+					bytes, unsigned, must not be lower
+					than requested bytes.
+	Requested flags	(4 bytes)	GFP flags supplied by the caller.
+	Target CPU	(4 bytes)	Signed integer, valid for event id 1.
+					If equal to -1, target CPU is the same
+					as origin CPU, but the reverse might
+					not be true.
+
+The data is made available in the same endianness the machine has.
+
+Other event ids and type ids may be defined and added. Other fields may be
+added by increasing event size, but see below for details.
+Every modification to the ABI, including new id definitions, are followed
+by bumping the ABI version by one.
+
+Adding new data to the packet (features) is done at the end of the mandatory
+data:
+	Feature size	(2 byte)
+	Feature ID	(1 byte)
+	Feature data	(Feature size - 3 bytes)
+
+
+Users:
+	kmemtrace-user - git://repo.or.cz/kmemtrace-user.git
+

Documentation/ABI/testing/debugfs-pktcdvd

@@ -1,4 +1,4 @@
-What:           /debug/pktcdvd/pktcdvd[0-7]
+What:           /sys/kernel/debug/pktcdvd/pktcdvd[0-7]
 Date:           Oct. 2006
 KernelVersion:  2.6.20
 Contact:        Thomas Maier <balagi@justmail.de>
@@ -10,10 +10,10 @@ debugfs interface
 The pktcdvd module (packet writing driver) creates
 these files in debugfs:
 
-/debug/pktcdvd/pktcdvd[0-7]/
+/sys/kernel/debug/pktcdvd/pktcdvd[0-7]/
     info            (0444) Lots of driver statistics and infos.
 
 Example:
 -------
 
-cat /debug/pktcdvd/pktcdvd0/info
+cat /sys/kernel/debug/pktcdvd/pktcdvd0/info

Documentation/ABI/testing/sysfs-bus-pci

@@ -41,6 +41,49 @@ Description:
 		for the device and attempt to bind to it.  For example:
 		# echo "8086 10f5" > /sys/bus/pci/drivers/foo/new_id
 
+What:		/sys/bus/pci/drivers/.../remove_id
+Date:		February 2009
+Contact:	Chris Wright <chrisw@sous-sol.org>
+Description:
+		Writing a device ID to this file will remove an ID
+		that was dynamically added via the new_id sysfs entry.
+		The format for the device ID is:
+		VVVV DDDD SVVV SDDD CCCC MMMM.	That is Vendor ID, Device
+		ID, Subsystem Vendor ID, Subsystem Device ID, Class,
+		and Class Mask.  The Vendor ID and Device ID fields are
+		required, the rest are optional.  After successfully
+		removing an ID, the driver will no longer support the
+		device.  This is useful to ensure auto probing won't
+		match the driver to the device.  For example:
+		# echo "8086 10f5" > /sys/bus/pci/drivers/foo/remove_id
+
+What:		/sys/bus/pci/rescan
+Date:		January 2009
+Contact:	Linux PCI developers <linux-pci@vger.kernel.org>
+Description:
+		Writing a non-zero value to this attribute will
+		force a rescan of all PCI buses in the system, and
+		re-discover previously removed devices.
+		Depends on CONFIG_HOTPLUG.
+
+What:		/sys/bus/pci/devices/.../remove
+Date:		January 2009
+Contact:	Linux PCI developers <linux-pci@vger.kernel.org>
+Description:
+		Writing a non-zero value to this attribute will
+		hot-remove the PCI device and any of its children.
+		Depends on CONFIG_HOTPLUG.
+
+What:		/sys/bus/pci/devices/.../rescan
+Date:		January 2009
+Contact:	Linux PCI developers <linux-pci@vger.kernel.org>
+Description:
+		Writing a non-zero value to this attribute will
+		force a rescan of the device's parent bus and all
+		child buses, and re-discover devices removed earlier
+		from this part of the device tree.
+		Depends on CONFIG_HOTPLUG.
+
 What:		/sys/bus/pci/devices/.../vpd
 Date:		February 2008
 Contact:	Ben Hutchings <bhutchings@solarflare.com>
@@ -52,3 +95,30 @@ Description:
 		that some devices may have malformatted data.  If the
 		underlying VPD has a writable section then the
 		corresponding section of this file will be writable.
+
+What:		/sys/bus/pci/devices/.../virtfnN
+Date:		March 2009
+Contact:	Yu Zhao <yu.zhao@intel.com>
+Description:
+		This symbolic link appears when hardware supports the SR-IOV
+		capability and the Physical Function driver has enabled it.
+		The symbolic link points to the PCI device sysfs entry of the
+		Virtual Function whose index is N (0...MaxVFs-1).
+
+What:		/sys/bus/pci/devices/.../dep_link
+Date:		March 2009
+Contact:	Yu Zhao <yu.zhao@intel.com>
+Description:
+		This symbolic link appears when hardware supports the SR-IOV
+		capability and the Physical Function driver has enabled it,
+		and this device has vendor specific dependencies with others.
+		The symbolic link points to the PCI device sysfs entry of
+		Physical Function this device depends on.
+
+What:		/sys/bus/pci/devices/.../physfn
+Date:		March 2009
+Contact:	Yu Zhao <yu.zhao@intel.com>
+Description:
+		This symbolic link appears when a device is a Virtual Function.
+		The symbolic link points to the PCI device sysfs entry of the
+		Physical Function this device associates with.

Documentation/ABI/testing/sysfs-class-regulator

@@ -4,8 +4,8 @@ KernelVersion:	2.6.26
 Contact:	Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
 		Some regulator directories will contain a field called
-		state. This reports the regulator enable status, for
-		regulators which can report that value.
+		state. This reports the regulator enable control, for
+		regulators which can report that input value.
 
 		This will be one of the following strings:
 
@@ -14,16 +14,54 @@ Description:
 		'unknown'
 
 		'enabled' means the regulator output is ON and is supplying
-		power to the system.
+		power to the system (assuming no error prevents it).
 
 		'disabled' means the regulator output is OFF and is not
-		supplying power to the system..
+		supplying power to the system (unless some non-Linux
+		control has enabled it).
 
 		'unknown' means software cannot determine the state, or
 		the reported state is invalid.
 
 		NOTE: this field can be used in conjunction with microvolts
-		and microamps to determine regulator output levels.
+		or microamps to determine configured regulator output levels.
+
+
+What:		/sys/class/regulator/.../status
+Description:
+		Some regulator directories will contain a field called
+		"status". This reports the current regulator status, for
+		regulators which can report that output value.
+
+		This will be one of the following strings:
+
+			off
+			on
+			error
+			fast
+			normal
+			idle
+			standby
+
+		"off" means the regulator is not supplying power to the
+		system.
+
+		"on" means the regulator is supplying power to the system,
+		and the regulator can't report a detailed operation mode.
+
+		"error" indicates an out-of-regulation status such as being
+		disabled due to thermal shutdown, or voltage being unstable
+		because of problems with the input power supply.
+
+		"fast", "normal", "idle", and "standby" are all detailed
+		regulator operation modes (described elsewhere).  They
+		imply "on", but provide more detail.
+
+		Note that regulator status is a function of many inputs,
+		not limited to control inputs from Linux.  For example,
+		the actual load presented may trigger "error" status; or
+		a regulator may be enabled by another user, even though
+		Linux did not enable it.
 
 
 What:		/sys/class/regulator/.../type
@@ -58,7 +96,7 @@ Description:
 		Some regulator directories will contain a field called
 		microvolts. This holds the regulator output voltage setting
 		measured in microvolts (i.e. E-6 Volts), for regulators
-		which can report that voltage.
+		which can report the control input for voltage.
 
 		NOTE: This value should not be used to determine the regulator
 		output voltage level as this value is the same regardless of
@@ -73,7 +111,7 @@ Description:
 		Some regulator directories will contain a field called
 		microamps. This holds the regulator output current limit
 		setting measured in microamps (i.e. E-6 Amps), for regulators
-		which can report that current.
+		which can report the control input for a current limit.
 
 		NOTE: This value should not be used to determine the regulator
 		output current level as this value is the same regardless of
@@ -87,7 +125,7 @@ Contact:	Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
 		Some regulator directories will contain a field called
 		opmode. This holds the current regulator operating mode,
-		for regulators which can report it.
+		for regulators which can report that control input value.
 
 		The opmode value can be one of the following strings:
 
@@ -101,7 +139,8 @@ Description:
 
 		NOTE: This value should not be used to determine the regulator
 		output operating mode as this value is the same regardless of
-		whether the regulator is enabled or disabled.
+		whether the regulator is enabled or disabled.  A "status"
+		attribute may be available to determine the actual mode.
 
 
 What:		/sys/class/regulator/.../min_microvolts

Documentation/ABI/testing/sysfs-firmware-acpi

@@ -69,9 +69,13 @@ Description:
 		gpe1F:	     0	invalid
 		gpe_all:    1192
 		sci:	1194
+		sci_not:     0	
 
-		sci - The total number of times the ACPI SCI
-		has claimed an interrupt.
+		sci - The number of times the ACPI SCI
+		has been called and claimed an interrupt.
+
+		sci_not - The number of times the ACPI SCI
+		has been called and NOT claimed an interrupt.
 
 		gpe_all - count of SCI caused by GPEs.
 

Documentation/ABI/testing/sysfs-fs-ext4

@@ -0,0 +1,81 @@
+What:		/sys/fs/ext4/<disk>/mb_stats
+Date:		March 2008
+Contact:	"Theodore Ts'o" <tytso@mit.edu>
+Description:
+		 Controls whether the multiblock allocator should
+		 collect statistics, which are shown during the unmount.
+		 1 means to collect statistics, 0 means not to collect
+		 statistics
+
+What:		/sys/fs/ext4/<disk>/mb_group_prealloc
+Date:		March 2008
+Contact:	"Theodore Ts'o" <tytso@mit.edu>
+Description:
+		The multiblock allocator will round up allocation
+		requests to a multiple of this tuning parameter if the
+		stripe size is not set in the ext4 superblock
+
+What:		/sys/fs/ext4/<disk>/mb_max_to_scan
+Date:		March 2008
+Contact:	"Theodore Ts'o" <tytso@mit.edu>
+Description:
+		The maximum number of extents the multiblock allocator
+		will search to find the best extent
+
+What:		/sys/fs/ext4/<disk>/mb_min_to_scan
+Date:		March 2008
+Contact:	"Theodore Ts'o" <tytso@mit.edu>
+Description:
+		The minimum number of extents the multiblock allocator
+		will search to find the best extent
+
+What:		/sys/fs/ext4/<disk>/mb_order2_req
+Date:		March 2008
+Contact:	"Theodore Ts'o" <tytso@mit.edu>
+Description:
+		Tuning parameter which controls the minimum size for 
+		requests (as a power of 2) where the buddy cache is
+		used
+
+What:		/sys/fs/ext4/<disk>/mb_stream_req
+Date:		March 2008
+Contact:	"Theodore Ts'o" <tytso@mit.edu>
+Description:
+		Files which have fewer blocks than this tunable
+		parameter will have their blocks allocated out of a
+		block group specific preallocation pool, so that small
+		files are packed closely together.  Each large file
+		 will have its blocks allocated out of its own unique
+		 preallocation pool.
+
+What:		/sys/fs/ext4/<disk>/inode_readahead
+Date:		March 2008
+Contact:	"Theodore Ts'o" <tytso@mit.edu>
+Description:
+		Tuning parameter which controls the maximum number of
+		inode table blocks that ext4's inode table readahead
+		algorithm will pre-read into the buffer cache
+
+What:		/sys/fs/ext4/<disk>/delayed_allocation_blocks
+Date:		March 2008
+Contact:	"Theodore Ts'o" <tytso@mit.edu>
+Description:
+		This file is read-only and shows the number of blocks
+		that are dirty in the page cache, but which do not
+		have their location in the filesystem allocated yet.
+
+What:		/sys/fs/ext4/<disk>/lifetime_write_kbytes
+Date:		March 2008
+Contact:	"Theodore Ts'o" <tytso@mit.edu>
+Description:
+		This file is read-only and shows the number of kilobytes
+		of data that have been written to this filesystem since it was
+		created.
+
+What:		/sys/fs/ext4/<disk>/session_write_kbytes
+Date:		March 2008
+Contact:	"Theodore Ts'o" <tytso@mit.edu>
+Description:
+		This file is read-only and shows the number of
+		kilobytes of data that have been written to this
+		filesystem since it was mounted.

Documentation/DMA-API.txt

@@ -609,3 +609,109 @@ size is the size (and should be a page-sized multiple).
 The return value will be either a pointer to the processor virtual
 address of the memory, or an error (via PTR_ERR()) if any part of the
 region is occupied.
+
+Part III - Debug drivers use of the DMA-API
+-------------------------------------------
+
+The DMA-API as described above as some constraints. DMA addresses must be
+released with the corresponding function with the same size for example. With
+the advent of hardware IOMMUs it becomes more and more important that drivers
+do not violate those constraints. In the worst case such a violation can
+result in data corruption up to destroyed filesystems.
+
+To debug drivers and find bugs in the usage of the DMA-API checking code can
+be compiled into the kernel which will tell the developer about those
+violations. If your architecture supports it you can select the "Enable
+debugging of DMA-API usage" option in your kernel configuration. Enabling this
+option has a performance impact. Do not enable it in production kernels.
+
+If you boot the resulting kernel will contain code which does some bookkeeping
+about what DMA memory was allocated for which device. If this code detects an
+error it prints a warning message with some details into your kernel log. An
+example warning message may look like this:
+
+------------[ cut here ]------------
+WARNING: at /data2/repos/linux-2.6-iommu/lib/dma-debug.c:448
+	check_unmap+0x203/0x490()
+Hardware name:
+forcedeth 0000:00:08.0: DMA-API: device driver frees DMA memory with wrong
+	function [device address=0x00000000640444be] [size=66 bytes] [mapped as
+single] [unmapped as page]
+Modules linked in: nfsd exportfs bridge stp llc r8169
+Pid: 0, comm: swapper Tainted: G        W  2.6.28-dmatest-09289-g8bb99c0 #1
+Call Trace:
+ <IRQ>  [<ffffffff80240b22>] warn_slowpath+0xf2/0x130
+ [<ffffffff80647b70>] _spin_unlock+0x10/0x30
+ [<ffffffff80537e75>] usb_hcd_link_urb_to_ep+0x75/0xc0
+ [<ffffffff80647c22>] _spin_unlock_irqrestore+0x12/0x40
+ [<ffffffff8055347f>] ohci_urb_enqueue+0x19f/0x7c0
+ [<ffffffff80252f96>] queue_work+0x56/0x60
+ [<ffffffff80237e10>] enqueue_task_fair+0x20/0x50
+ [<ffffffff80539279>] usb_hcd_submit_urb+0x379/0xbc0
+ [<ffffffff803b78c3>] cpumask_next_and+0x23/0x40
+ [<ffffffff80235177>] find_busiest_group+0x207/0x8a0
+ [<ffffffff8064784f>] _spin_lock_irqsave+0x1f/0x50
+ [<ffffffff803c7ea3>] check_unmap+0x203/0x490
+ [<ffffffff803c8259>] debug_dma_unmap_page+0x49/0x50
+ [<ffffffff80485f26>] nv_tx_done_optimized+0xc6/0x2c0
+ [<ffffffff80486c13>] nv_nic_irq_optimized+0x73/0x2b0
+ [<ffffffff8026df84>] handle_IRQ_event+0x34/0x70
+ [<ffffffff8026ffe9>] handle_edge_irq+0xc9/0x150
+ [<ffffffff8020e3ab>] do_IRQ+0xcb/0x1c0
+ [<ffffffff8020c093>] ret_from_intr+0x0/0xa
+ <EOI> <4>---[ end trace f6435a98e2a38c0e ]---
+
+The driver developer can find the driver and the device including a stacktrace
+of the DMA-API call which caused this warning.
+
+Per default only the first error will result in a warning message. All other
+errors will only silently counted. This limitation exist to prevent the code
+from flooding your kernel log. To support debugging a device driver this can
+be disabled via debugfs. See the debugfs interface documentation below for
+details.
+
+The debugfs directory for the DMA-API debugging code is called dma-api/. In
+this directory the following files can currently be found:
+
+	dma-api/all_errors	This file contains a numeric value. If this
+				value is not equal to zero the debugging code
+				will print a warning for every error it finds
+				into the kernel log. Be carefull with this
+				option. It can easily flood your logs.
+
+	dma-api/disabled	This read-only file contains the character 'Y'
+				if the debugging code is disabled. This can
+				happen when it runs out of memory or if it was
+				disabled at boot time
+
+	dma-api/error_count	This file is read-only and shows the total
+				numbers of errors found.
+
+	dma-api/num_errors	The number in this file shows how many
+				warnings will be printed to the kernel log
+				before it stops. This number is initialized to
+				one at system boot and be set by writing into
+				this file
+
+	dma-api/min_free_entries
+				This read-only file can be read to get the
+				minimum number of free dma_debug_entries the
+				allocator has ever seen. If this value goes
+				down to zero the code will disable itself
+				because it is not longer reliable.
+
+	dma-api/num_free_entries
+				The current number of free dma_debug_entries
+				in the allocator.
+
+If you have this code compiled into your kernel it will be enabled by default.
+If you want to boot without the bookkeeping anyway you can provide
+'dma_debug=off' as a boot parameter. This will disable DMA-API debugging.
+Notice that you can not enable it again at runtime. You have to reboot to do
+so.
+
+When the code disables itself at runtime this is most likely because it ran
+out of dma_debug_entries. These entries are preallocated at boot. The number
+of preallocated entries is defined per architecture. If it is too low for you
+boot with 'dma_debug_entries=<your_desired_number>' to overwrite the
+architectural default.

Documentation/DMA-mapping.txt

@@ -136,7 +136,7 @@ exactly why.
 The standard 32-bit addressing PCI device would do something like
 this:
 
-	if (pci_set_dma_mask(pdev, DMA_32BIT_MASK)) {
+	if (pci_set_dma_mask(pdev, DMA_BIT_MASK(32))) {
 		printk(KERN_WARNING
 		       "mydev: No suitable DMA available.\n");
 		goto ignore_this_device;
@@ -155,9 +155,9 @@ all 64-bits when accessing streaming DMA:
 
 	int using_dac;
 
-	if (!pci_set_dma_mask(pdev, DMA_64BIT_MASK)) {
+	if (!pci_set_dma_mask(pdev, DMA_BIT_MASK(64))) {
 		using_dac = 1;
-	} else if (!pci_set_dma_mask(pdev, DMA_32BIT_MASK)) {
+	} else if (!pci_set_dma_mask(pdev, DMA_BIT_MASK(32))) {
 		using_dac = 0;
 	} else {
 		printk(KERN_WARNING
@@ -170,14 +170,14 @@ the case would look like this:
 
 	int using_dac, consistent_using_dac;
 
-	if (!pci_set_dma_mask(pdev, DMA_64BIT_MASK)) {
+	if (!pci_set_dma_mask(pdev, DMA_BIT_MASK(64))) {
 		using_dac = 1;
 	   	consistent_using_dac = 1;
-		pci_set_consistent_dma_mask(pdev, DMA_64BIT_MASK);
-	} else if (!pci_set_dma_mask(pdev, DMA_32BIT_MASK)) {
+		pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64));
+	} else if (!pci_set_dma_mask(pdev, DMA_BIT_MASK(32))) {
 		using_dac = 0;
 		consistent_using_dac = 0;
-		pci_set_consistent_dma_mask(pdev, DMA_32BIT_MASK);
+		pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
 	} else {
 		printk(KERN_WARNING
 		       "mydev: No suitable DMA available.\n");
@@ -192,7 +192,7 @@ check the return value from pci_set_consistent_dma_mask().
 Finally, if your device can only drive the low 24-bits of
 address during PCI bus mastering you might do something like:
 
-	if (pci_set_dma_mask(pdev, DMA_24BIT_MASK)) {
+	if (pci_set_dma_mask(pdev, DMA_BIT_MASK(24))) {
 		printk(KERN_WARNING
 		       "mydev: 24-bit DMA addressing not available.\n");
 		goto ignore_this_device;
@@ -213,7 +213,7 @@ most specific mask.
 
 Here is pseudo-code showing how this might be done:
 
-	#define PLAYBACK_ADDRESS_BITS	DMA_32BIT_MASK
+	#define PLAYBACK_ADDRESS_BITS	DMA_BIT_MASK(32)
 	#define RECORD_ADDRESS_BITS	0x00ffffff
 
 	struct my_sound_card *card;

Documentation/DocBook/.gitignore

@@ -4,3 +4,7 @@
 *.html
 *.9.gz
 *.9
+*.aux
+*.dvi
+*.log
+*.out

Documentation/DocBook/Makefile

@@ -31,7 +31,7 @@ PS_METHOD	= $(prefer-db2x)
 
 ###
 # The targets that may be used.
-PHONY += xmldocs sgmldocs psdocs pdfdocs htmldocs mandocs installmandocs
+PHONY += xmldocs sgmldocs psdocs pdfdocs htmldocs mandocs installmandocs cleandocs
 
 BOOKS := $(addprefix $(obj)/,$(DOCBOOKS))
 xmldocs: $(BOOKS)
@@ -143,7 +143,8 @@ quiet_cmd_db2pdf = PDF     $@
 	$(call cmd,db2pdf)
 
 
-main_idx = Documentation/DocBook/index.html
+index = index.html
+main_idx = Documentation/DocBook/$(index)
 build_main_index = rm -rf $(main_idx) && \
 		   echo '<h1>Linux Kernel HTML Documentation</h1>' >> $(main_idx) && \
 		   echo '<h2>Kernel Version: $(KERNELVERSION)</h2>' >> $(main_idx) && \
@@ -213,11 +214,12 @@ silent_gen_xml = :
 dochelp:
 	@echo  ' Linux kernel internal documentation in different formats:'
 	@echo  '  htmldocs        - HTML'
-	@echo  '  installmandocs  - install man pages generated by mandocs'
-	@echo  '  mandocs         - man pages'
 	@echo  '  pdfdocs         - PDF'
 	@echo  '  psdocs          - Postscript'
 	@echo  '  xmldocs         - XML DocBook'
+	@echo  '  mandocs         - man pages'
+	@echo  '  installmandocs  - install man pages generated by mandocs'
+	@echo  '  cleandocs       - clean all generated DocBook files'
 
 ###
 # Temporary files left by various tools
@@ -231,10 +233,14 @@ clean-files := $(DOCBOOKS) \
 	$(patsubst %.xml, %.pdf,  $(DOCBOOKS)) \
 	$(patsubst %.xml, %.html, $(DOCBOOKS)) \
 	$(patsubst %.xml, %.9,    $(DOCBOOKS)) \
-	$(C-procfs-example)
+	$(C-procfs-example) $(index)
 
 clean-dirs := $(patsubst %.xml,%,$(DOCBOOKS)) man
 
+cleandocs:
+	$(Q)rm -f $(call objectify, $(clean-files))
+	$(Q)rm -rf $(call objectify, $(clean-dirs))
+
 # Declare the contents of the .PHONY variable as phony.  We keep that
 # information in a variable se we can use it in if_changed and friends.
 

Documentation/DocBook/kernel-api.tmpl

@@ -190,15 +190,20 @@ X!Ekernel/module.c
 !Edrivers/pci/pci.c
 !Edrivers/pci/pci-driver.c
 !Edrivers/pci/remove.c
-!Edrivers/pci/pci-acpi.c
 !Edrivers/pci/search.c
 !Edrivers/pci/msi.c
 !Edrivers/pci/bus.c
+!Edrivers/pci/access.c
+!Edrivers/pci/irq.c
+!Edrivers/pci/htirq.c
 <!-- FIXME: Removed for now since no structured comments in source
 X!Edrivers/pci/hotplug.c
 -->
 !Edrivers/pci/probe.c
+!Edrivers/pci/slot.c
 !Edrivers/pci/rom.c
+!Edrivers/pci/iov.c
+!Idrivers/pci/pci-sysfs.c
      </sect1>
      <sect1><title>PCI Hotplug Support Library</title>
 !Edrivers/pci/hotplug/pci_hotplug_core.c
@@ -258,7 +263,7 @@ X!Earch/x86/kernel/mca_32.c
 !Eblock/blk-tag.c
 !Iblock/blk-tag.c
 !Eblock/blk-integrity.c
-!Iblock/blktrace.c
+!Ikernel/trace/blktrace.c
 !Iblock/genhd.c
 !Eblock/genhd.c
   </chapter>

Documentation/DocBook/procfs_example.c

@@ -117,9 +117,6 @@ static int __init init_procfs_example(void)
 		rv = -ENOMEM;
 		goto out;
 	}
-	
-	example_dir->owner = THIS_MODULE;
-	
 	/* create jiffies using convenience function */
 	jiffies_file = create_proc_read_entry("jiffies", 
 					      0444, example_dir, 
@@ -130,8 +127,6 @@ static int __init init_procfs_example(void)
 		goto no_jiffies;
 	}
 
-	jiffies_file->owner = THIS_MODULE;
-
 	/* create foo and bar files using same callback
 	 * functions 
 	 */
@@ -146,7 +141,6 @@ static int __init init_procfs_example(void)
 	foo_file->data = &foo_data;
 	foo_file->read_proc = proc_read_foobar;
 	foo_file->write_proc = proc_write_foobar;
-	foo_file->owner = THIS_MODULE;
 		
 	bar_file = create_proc_entry("bar", 0644, example_dir);
 	if(bar_file == NULL) {
@@ -159,7 +153,6 @@ static int __init init_procfs_example(void)
 	bar_file->data = &bar_data;
 	bar_file->read_proc = proc_read_foobar;
 	bar_file->write_proc = proc_write_foobar;
-	bar_file->owner = THIS_MODULE;
 		
 	/* create symlink */
 	symlink = proc_symlink("jiffies_too", example_dir, 
@@ -169,8 +162,6 @@ static int __init init_procfs_example(void)
 		goto no_symlink;
 	}
 
-	symlink->owner = THIS_MODULE;
-
 	/* everything OK */
 	printk(KERN_INFO "%s %s initialised\n",
 	       MODULE_NAME, MODULE_VERS);

Documentation/DocBook/writing-an-alsa-driver.tmpl

@@ -1137,8 +1137,8 @@
           if (err < 0)
                   return err;
           /* check PCI availability (28bit DMA) */
-          if (pci_set_dma_mask(pci, DMA_28BIT_MASK) < 0 ||
-              pci_set_consistent_dma_mask(pci, DMA_28BIT_MASK) < 0) {
+          if (pci_set_dma_mask(pci, DMA_BIT_MASK(28)) < 0 ||
+              pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(28)) < 0) {
                   printk(KERN_ERR "error to set 28bit mask DMA\n");
                   pci_disable_device(pci);
                   return -ENXIO;
@@ -1252,8 +1252,8 @@
   err = pci_enable_device(pci);
   if (err < 0)
           return err;
-  if (pci_set_dma_mask(pci, DMA_28BIT_MASK) < 0 ||
-      pci_set_consistent_dma_mask(pci, DMA_28BIT_MASK) < 0) {
+  if (pci_set_dma_mask(pci, DMA_BIT_MASK(28)) < 0 ||
+      pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(28)) < 0) {
           printk(KERN_ERR "error to set 28bit mask DMA\n");
           pci_disable_device(pci);
           return -ENXIO;

Documentation/PCI/MSI-HOWTO.txt

@@ -4,506 +4,356 @@
 	Revised Feb 12, 2004 by Martine Silbermann
 		email: Martine.Silbermann@hp.com
 	Revised Jun 25, 2004 by Tom L Nguyen
+	Revised Jul  9, 2008 by Matthew Wilcox <willy@linux.intel.com>
+		Copyright 2003, 2008 Intel Corporation
 
 1. About this guide
 
-This guide describes the basics of Message Signaled Interrupts (MSI),
-the advantages of using MSI over traditional interrupt mechanisms,
-and how to enable your driver to use MSI or MSI-X. Also included is
-a Frequently Asked Questions (FAQ) section.
-
-1.1 Terminology
-
-PCI devices can be single-function or multi-function.  In either case,
-when this text talks about enabling or disabling MSI on a "device
-function," it is referring to one specific PCI device and function and
-not to all functions on a PCI device (unless the PCI device has only
-one function).
-
-2. Copyright 2003 Intel Corporation
-
-3. What is MSI/MSI-X?
-
-Message Signaled Interrupt (MSI), as described in the PCI Local Bus
-Specification Revision 2.3 or later, is an optional feature, and a
-required feature for PCI Express devices. MSI enables a device function
-to request service by sending an Inbound Memory Write on its PCI bus to
-the FSB as a Message Signal Interrupt transaction. Because MSI is
-generated in the form of a Memory Write, all transaction conditions,
-such as a Retry, Master-Abort, Target-Abort or normal completion, are
-supported.
-
-A PCI device that supports MSI must also support pin IRQ assertion
-interrupt mechanism to provide backward compatibility for systems that
-do not support MSI. In systems which support MSI, the bus driver is
-responsible for initializing the message address and message data of
-the device function's MSI/MSI-X capability structure during device
-initial configuration.
-
-An MSI capable device function indicates MSI support by implementing
-the MSI/MSI-X capability structure in its PCI capability list. The
-device function may implement both the MSI capability structure and
-the MSI-X capability structure; however, the bus driver should not
-enable both.
-
-The MSI capability structure contains Message Control register,
-Message Address register and Message Data register. These registers
-provide the bus driver control over MSI. The Message Control register
-indicates the MSI capability supported by the device. The Message
-Address register specifies the target address and the Message Data
-register specifies the characteristics of the message. To request
-service, the device function writes the content of the Message Data
-register to the target address. The device and its software driver
-are prohibited from writing to these registers.
-
-The MSI-X capability structure is an optional extension to MSI. It
-uses an independent and separate capability structure. There are
-some key advantages to implementing the MSI-X capability structure
-over the MSI capability structure as described below.
-
-	- Support a larger maximum number of vectors per function.
-
-	- Provide the ability for system software to configure
-	each vector with an independent message address and message
-	data, specified by a table that resides in Memory Space.
-
-        - MSI and MSI-X both support per-vector masking. Per-vector
-	masking is an optional extension of MSI but a required
-	feature for MSI-X. Per-vector masking provides the kernel the
-	ability to mask/unmask a single MSI while running its
-	interrupt service routine. If per-vector masking is
-	not supported, then the device driver should provide the
-	hardware/software synchronization to ensure that the device
-	generates MSI when the driver wants it to do so.
-
-4. Why use MSI?
-
-As a benefit to the simplification of board design, MSI allows board
-designers to remove out-of-band interrupt routing. MSI is another
-step towards a legacy-free environment.
-
-Due to increasing pressure on chipset and processor packages to
-reduce pin count, the need for interrupt pins is expected to
-diminish over time. Devices, due to pin constraints, may implement
-messages to increase performance.
-
-PCI Express endpoints uses INTx emulation (in-band messages) instead
-of IRQ pin assertion. Using INTx emulation requires interrupt
-sharing among devices connected to the same node (PCI bridge) while
-MSI is unique (non-shared) and does not require BIOS configuration
-support. As a result, the PCI Express technology requires MSI
-support for better interrupt performance.
-
-Using MSI enables the device functions to support two or more
-vectors, which can be configured to target different CPUs to
-increase scalability.
-
-5. Configuring a driver to use MSI/MSI-X
-
-By default, the kernel will not enable MSI/MSI-X on all devices that
-support this capability. The CONFIG_PCI_MSI kernel option
-must be selected to enable MSI/MSI-X support.
-
-5.1 Including MSI/MSI-X support into the kernel
-
-To allow MSI/MSI-X capable device drivers to selectively enable
-MSI/MSI-X (using pci_enable_msi()/pci_enable_msix() as described
-below), the VECTOR based scheme needs to be enabled by setting
-CONFIG_PCI_MSI during kernel config.
-
-Since the target of the inbound message is the local APIC, providing
-CONFIG_X86_LOCAL_APIC must be enabled as well as CONFIG_PCI_MSI.
-
-5.2 Configuring for MSI support
-
-Due to the non-contiguous fashion in vector assignment of the
-existing Linux kernel, this version does not support multiple
-messages regardless of a device function is capable of supporting
-more than one vector. To enable MSI on a device function's MSI
-capability structure requires a device driver to call the function
-pci_enable_msi() explicitly.
-
-5.2.1 API pci_enable_msi
+This guide describes the basics of Message Signaled Interrupts (MSIs),
+the advantages of using MSI over traditional interrupt mechanisms, how
+to change your driver to use MSI or MSI-X and some basic diagnostics to
+try if a device doesn't support MSIs.
 
-int pci_enable_msi(struct pci_dev *dev)
 
-With this new API, a device driver that wants to have MSI
-enabled on its device function must call this API to enable MSI.
-A successful call will initialize the MSI capability structure
-with ONE vector, regardless of whether a device function is
-capable of supporting multiple messages. This vector replaces the
-pre-assigned dev->irq with a new MSI vector. To avoid a conflict
-of the new assigned vector with existing pre-assigned vector requires
-a device driver to call this API before calling request_irq().
+2. What are MSIs?
 
-5.2.2 API pci_disable_msi
+A Message Signaled Interrupt is a write from the device to a special
+address which causes an interrupt to be received by the CPU.
 
-void pci_disable_msi(struct pci_dev *dev)
+The MSI capability was first specified in PCI 2.2 and was later enhanced
+in PCI 3.0 to allow each interrupt to be masked individually.  The MSI-X
+capability was also introduced with PCI 3.0.  It supports more interrupts
+per device than MSI and allows interrupts to be independently configured.
 
-This API should always be used to undo the effect of pci_enable_msi()
-when a device driver is unloading. This API restores dev->irq with
-the pre-assigned IOAPIC vector and switches a device's interrupt
-mode to PCI pin-irq assertion/INTx emulation mode.
-
-Note that a device driver should always call free_irq() on the MSI vector
-that it has done request_irq() on before calling this API. Failure to do
-so results in a BUG_ON() and a device will be left with MSI enabled and
-leaks its vector.
-
-5.2.3 MSI mode vs. legacy mode diagram
-
-The below diagram shows the events which switch the interrupt
-mode on the MSI-capable device function between MSI mode and
-PIN-IRQ assertion mode.
-
-	 ------------   pci_enable_msi 	 ------------------------
-	|	     | <===============	| 			 |
-	| MSI MODE   |	  	     	| PIN-IRQ ASSERTION MODE |
-	| 	     | ===============>	|			 |
- 	 ------------	pci_disable_msi  ------------------------
-
-
-Figure 1. MSI Mode vs. Legacy Mode
-
-In Figure 1, a device operates by default in legacy mode. Legacy
-in this context means PCI pin-irq assertion or PCI-Express INTx
-emulation. A successful MSI request (using pci_enable_msi()) switches
-a device's interrupt mode to MSI mode. A pre-assigned IOAPIC vector
-stored in dev->irq will be saved by the PCI subsystem and a new
-assigned MSI vector will replace dev->irq.
-
-To return back to its default mode, a device driver should always call
-pci_disable_msi() to undo the effect of pci_enable_msi(). Note that a
-device driver should always call free_irq() on the MSI vector it has
-done request_irq() on before calling pci_disable_msi(). Failure to do
-so results in a BUG_ON() and a device will be left with MSI enabled and
-leaks its vector. Otherwise, the PCI subsystem restores a device's
-dev->irq with a pre-assigned IOAPIC vector and marks the released
-MSI vector as unused.
-
-Once being marked as unused, there is no guarantee that the PCI
-subsystem will reserve this MSI vector for a device. Depending on
-the availability of current PCI vector resources and the number of
-MSI/MSI-X requests from other drivers, this MSI may be re-assigned.
-
-For the case where the PCI subsystem re-assigns this MSI vector to
-another driver, a request to switch back to MSI mode may result
-in being assigned a different MSI vector or a failure if no more
-vectors are available.
-
-5.3 Configuring for MSI-X support
-
-Due to the ability of the system software to configure each vector of
-the MSI-X capability structure with an independent message address
-and message data, the non-contiguous fashion in vector assignment of
-the existing Linux kernel has no impact on supporting multiple
-messages on an MSI-X capable device functions. To enable MSI-X on
-a device function's MSI-X capability structure requires its device
-driver to call the function pci_enable_msix() explicitly.
-
-The function pci_enable_msix(), once invoked, enables either
-all or nothing, depending on the current availability of PCI vector
-resources. If the PCI vector resources are available for the number
-of vectors requested by a device driver, this function will configure
-the MSI-X table of the MSI-X capability structure of a device with
-requested messages. To emphasize this reason, for example, a device
-may be capable for supporting the maximum of 32 vectors while its
-software driver usually may request 4 vectors. It is recommended
-that the device driver should call this function once during the
-initialization phase of the device driver.
-
-Unlike the function pci_enable_msi(), the function pci_enable_msix()
-does not replace the pre-assigned IOAPIC dev->irq with a new MSI
-vector because the PCI subsystem writes the 1:1 vector-to-entry mapping
-into the field vector of each element contained in a second argument.
-Note that the pre-assigned IOAPIC dev->irq is valid only if the device
-operates in PIN-IRQ assertion mode. In MSI-X mode, any attempt at
-using dev->irq by the device driver to request for interrupt service
-may result in unpredictable behavior.
-
-For each MSI-X vector granted, a device driver is responsible for calling
-other functions like request_irq(), enable_irq(), etc. to enable
-this vector with its corresponding interrupt service handler. It is
-a device driver's choice to assign all vectors with the same
-interrupt service handler or each vector with a unique interrupt
-service handler.
-
-5.3.1 Handling MMIO address space of MSI-X Table
-
-The PCI 3.0 specification has implementation notes that MMIO address
-space for a device's MSI-X structure should be isolated so that the
-software system can set different pages for controlling accesses to the
-MSI-X structure. The implementation of MSI support requires the PCI
-subsystem, not a device driver, to maintain full control of the MSI-X
-table/MSI-X PBA (Pending Bit Array) and MMIO address space of the MSI-X
-table/MSI-X PBA.  A device driver should not access the MMIO address
-space of the MSI-X table/MSI-X PBA.
-
-5.3.2 API pci_enable_msix
+Devices may support both MSI and MSI-X, but only one can be enabled at
+a time.
 
-int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec)
 
-This API enables a device driver to request the PCI subsystem
-to enable MSI-X messages on its hardware device. Depending on
-the availability of PCI vectors resources, the PCI subsystem enables
-either all or none of the requested vectors.
+3. Why use MSIs?
+
+There are three reasons why using MSIs can give an advantage over
+traditional pin-based interrupts.
+
+Pin-based PCI interrupts are often shared amongst several devices.
+To support this, the kernel must call each interrupt handler associated
+with an interrupt, which leads to reduced performance for the system as
+a whole.  MSIs are never shared, so this problem cannot arise.
+
+When a device writes data to memory, then raises a pin-based interrupt,
+it is possible that the interrupt may arrive before all the data has
+arrived in memory (this becomes more likely with devices behind PCI-PCI
+bridges).  In order to ensure that all the data has arrived in memory,
+the interrupt handler must read a register on the device which raised
+the interrupt.  PCI transaction ordering rules require that all the data
+arrives in memory before the value can be returned from the register.
+Using MSIs avoids this problem as the interrupt-generating write cannot
+pass the data writes, so by the time the interrupt is raised, the driver
+knows that all the data has arrived in memory.
+
+PCI devices can only support a single pin-based interrupt per function.
+Often drivers have to query the device to find out what event has
+occurred, slowing down interrupt handling for the common case.  With
+MSIs, a device can support more interrupts, allowing each interrupt
+to be specialised to a different purpose.  One possible design gives
+infrequent conditions (such as errors) their own interrupt which allows
+the driver to handle the normal interrupt handling path more efficiently.
+Other possible designs include giving one interrupt to each packet queue
+in a network card or each port in a storage controller.
+
+
+4. How to use MSIs
+
+PCI devices are initialised to use pin-based interrupts.  The device
+driver has to set up the device to use MSI or MSI-X.  Not all machines
+support MSIs correctly, and for those machines, the APIs described below
+will simply fail and the device will continue to use pin-based interrupts.
+
+4.1 Include kernel support for MSIs
+
+To support MSI or MSI-X, the kernel must be built with the CONFIG_PCI_MSI
+option enabled.  This option is only available on some architectures,
+and it may depend on some other options also being set.  For example,
+on x86, you must also enable X86_UP_APIC or SMP in order to see the
+CONFIG_PCI_MSI option.
+
+4.2 Using MSI
+
+Most of the hard work is done for the driver in the PCI layer.  It simply
+has to request that the PCI layer set up the MSI capability for this
+device.
+
+4.2.1 pci_enable_msi
+
+int pci_enable_msi(struct pci_dev *dev)
+
+A successful call will allocate ONE interrupt to the device, regardless
+of how many MSIs the device supports.  The device will be switched from
+pin-based interrupt mode to MSI mode.  The dev->irq number is changed
+to a new number which represents the message signaled interrupt.
+This function should be called before the driver calls request_irq()
+since enabling MSIs disables the pin-based IRQ and the driver will not
+receive interrupts on the old interrupt.
+
+4.2.2 pci_enable_msi_block
+
+int pci_enable_msi_block(struct pci_dev *dev, int count)
+
+This variation on the above call allows a device driver to request multiple
+MSIs.  The MSI specification only allows interrupts to be allocated in
+powers of two, up to a maximum of 2^5 (32).
+
+If this function returns 0, it has succeeded in allocating at least as many
+interrupts as the driver requested (it may have allocated more in order
+to satisfy the power-of-two requirement).  In this case, the function
+enables MSI on this device and updates dev->irq to be the lowest of
+the new interrupts assigned to it.  The other interrupts assigned to
+the device are in the range dev->irq to dev->irq + count - 1.
+
+If this function returns a negative number, it indicates an error and
+the driver should not attempt to request any more MSI interrupts for
+this device.  If this function returns a positive number, it will be
+less than 'count' and indicate the number of interrupts that could have
+been allocated.  In neither case will the irq value have been
+updated, nor will the device have been switched into MSI mode.
+
+The device driver must decide what action to take if
+pci_enable_msi_block() returns a value less than the number asked for.
+Some devices can make use of fewer interrupts than the maximum they
+request; in this case the driver should call pci_enable_msi_block()
+again.  Note that it is not guaranteed to succeed, even when the
+'count' has been reduced to the value returned from a previous call to
+pci_enable_msi_block().  This is because there are multiple constraints
+on the number of vectors that can be allocated; pci_enable_msi_block()
+will return as soon as it finds any constraint that doesn't allow the
+call to succeed.
+
+4.2.3 pci_disable_msi
+
+void pci_disable_msi(struct pci_dev *dev)
 
-Argument 'dev' points to the device (pci_dev) structure.
+This function should be used to undo the effect of pci_enable_msi() or
+pci_enable_msi_block().  Calling it restores dev->irq to the pin-based
+interrupt number and frees the previously allocated message signaled
+interrupt(s).  The interrupt may subsequently be assigned to another
+device, so drivers should not cache the value of dev->irq.
 
-Argument 'entries' is a pointer to an array of msix_entry structs.
-The number of entries is indicated in argument 'nvec'.
-struct msix_entry is defined in /driver/pci/msi.h:
+A device driver must always call free_irq() on the interrupt(s)
+for which it has called request_irq() before calling this function.
+Failure to do so will result in a BUG_ON(), the device will be left with
+MSI enabled and will leak its vector.
+
+4.3 Using MSI-X
+
+The MSI-X capability is much more flexible than the MSI capability.
+It supports up to 2048 interrupts, each of which can be controlled
+independently.  To support this flexibility, drivers must use an array of
+`struct msix_entry':
 
 struct msix_entry {
 	u16 	vector; /* kernel uses to write alloc vector */
 	u16	entry; /* driver uses to specify entry */
 };
 
-A device driver is responsible for initializing the field 'entry' of
-each element with a unique entry supported by MSI-X table. Otherwise,
--EINVAL will be returned as a result. A successful return of zero
-indicates the PCI subsystem completed initializing each of the requested
-entries of the MSI-X table with message address and message data.
-Last but not least, the PCI subsystem will write the 1:1
-vector-to-entry mapping into the field 'vector' of each element. A
-device driver is responsible for keeping track of allocated MSI-X
-vectors in its internal data structure.
-
-A return of zero indicates that the number of MSI-X vectors was
-successfully allocated. A return of greater than zero indicates
-MSI-X vector shortage. Or a return of less than zero indicates
-a failure. This failure may be a result of duplicate entries
-specified in second argument, or a result of no available vector,
-or a result of failing to initialize MSI-X table entries.
-
-5.3.3 API pci_disable_msix
+This allows for the device to use these interrupts in a sparse fashion;
+for example it could use interrupts 3 and 1027 and allocate only a
+two-element array.  The driver is expected to fill in the 'entry' value
+in each element of the array to indicate which entries it wants the kernel
+to assign interrupts for.  It is invalid to fill in two entries with the
+same number.
+
+4.3.1 pci_enable_msix
+
+int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec)
+
+Calling this function asks the PCI subsystem to allocate 'nvec' MSIs.
+The 'entries' argument is a pointer to an array of msix_entry structs
+which should be at least 'nvec' entries in size.  On success, the
+function will return 0 and the device will have been switched into
+MSI-X interrupt mode.  The 'vector' elements in each entry will have
+been filled in with the interrupt number.  The driver should then call
+request_irq() for each 'vector' that it decides to use.
+
+If this function returns a negative number, it indicates an error and
+the driver should not attempt to allocate any more MSI-X interrupts for
+this device.  If it returns a positive number, it indicates the maximum
+number of interrupt vectors that could have been allocated. See example
+below.
+
+This function, in contrast with pci_enable_msi(), does not adjust
+dev->irq.  The device will not generate interrupts for this interrupt
+number once MSI-X is enabled.  The device driver is responsible for
+keeping track of the interrupts assigned to the MSI-X vectors so it can
+free them again later.
+
+Device drivers should normally call this function once per device
+during the initialization phase.
+
+It is ideal if drivers can cope with a variable number of MSI-X interrupts,
+there are many reasons why the platform may not be able to provide the
+exact number a driver asks for.
+
+A request loop to achieve that might look like:
+
+static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
+{
+	while (nvec >= FOO_DRIVER_MINIMUM_NVEC) {
+		rc = pci_enable_msix(adapter->pdev,
+				     adapter->msix_entries, nvec);
+		if (rc > 0)
+			nvec = rc;
+		else
+			return rc;
+	}
+
+	return -ENOSPC;
+}
+
+4.3.2 pci_disable_msix
 
 void pci_disable_msix(struct pci_dev *dev)
 
-This API should always be used to undo the effect of pci_enable_msix()
-when a device driver is unloading. Note that a device driver should
-always call free_irq() on all MSI-X vectors it has done request_irq()
-on before calling this API. Failure to do so results in a BUG_ON() and
-a device will be left with MSI-X enabled and leaks its vectors.
-
-5.3.4 MSI-X mode vs. legacy mode diagram
-
-The below diagram shows the events which switch the interrupt
-mode on the MSI-X capable device function between MSI-X mode and
-PIN-IRQ assertion mode (legacy).
-
-	 ------------   pci_enable_msix(,,n) ------------------------
-	|	     | <===============	    | 			     |
-	| MSI-X MODE |	  	     	    | PIN-IRQ ASSERTION MODE |
-	| 	     | ===============>	    |			     |
- 	 ------------	pci_disable_msix     ------------------------
-
-Figure 2. MSI-X Mode vs. Legacy Mode
-
-In Figure 2, a device operates by default in legacy mode. A
-successful MSI-X request (using pci_enable_msix()) switches a
-device's interrupt mode to MSI-X mode. A pre-assigned IOAPIC vector
-stored in dev->irq will be saved by the PCI subsystem; however,
-unlike MSI mode, the PCI subsystem will not replace dev->irq with
-assigned MSI-X vector because the PCI subsystem already writes the 1:1
-vector-to-entry mapping into the field 'vector' of each element
-specified in second argument.
-
-To return back to its default mode, a device driver should always call
-pci_disable_msix() to undo the effect of pci_enable_msix(). Note that
-a device driver should always call free_irq() on all MSI-X vectors it
-has done request_irq() on before calling pci_disable_msix(). Failure
-to do so results in a BUG_ON() and a device will be left with MSI-X
-enabled and leaks its vectors. Otherwise, the PCI subsystem switches a
-device function's interrupt mode from MSI-X mode to legacy mode and
-marks all allocated MSI-X vectors as unused.
-
-Once being marked as unused, there is no guarantee that the PCI
-subsystem will reserve these MSI-X vectors for a device. Depending on
-the availability of current PCI vector resources and the number of
-MSI/MSI-X requests from other drivers, these MSI-X vectors may be
-re-assigned.
-
-For the case where the PCI subsystem re-assigned these MSI-X vectors
-to other drivers, a request to switch back to MSI-X mode may result
-being assigned with another set of MSI-X vectors or a failure if no
-more vectors are available.
-
-5.4 Handling function implementing both MSI and MSI-X capabilities
-
-For the case where a function implements both MSI and MSI-X
-capabilities, the PCI subsystem enables a device to run either in MSI
-mode or MSI-X mode but not both. A device driver determines whether it
-wants MSI or MSI-X enabled on its hardware device. Once a device
-driver requests for MSI, for example, it is prohibited from requesting
-MSI-X; in other words, a device driver is not permitted to ping-pong
-between MSI mod MSI-X mode during a run-time.
-
-5.5 Hardware requirements for MSI/MSI-X support
-
-MSI/MSI-X support requires support from both system hardware and
-individual hardware device functions.
-
-5.5.1 Required x86 hardware support
-
-Since the target of MSI address is the local APIC CPU, enabling
-MSI/MSI-X support in the Linux kernel is dependent on whether existing
-system hardware supports local APIC. Users should verify that their
-system supports local APIC operation by testing that it runs when
-CONFIG_X86_LOCAL_APIC=y.
-
-In SMP environment, CONFIG_X86_LOCAL_APIC is automatically set;
-however, in UP environment, users must manually set
-CONFIG_X86_LOCAL_APIC. Once CONFIG_X86_LOCAL_APIC=y, setting
-CONFIG_PCI_MSI enables the VECTOR based scheme and the option for
-MSI-capable device drivers to selectively enable MSI/MSI-X.
-
-Note that CONFIG_X86_IO_APIC setting is irrelevant because MSI/MSI-X
-vector is allocated new during runtime and MSI/MSI-X support does not
-depend on BIOS support. This key independency enables MSI/MSI-X
-support on future IOxAPIC free platforms.
-
-5.5.2 Device hardware support
-
-The hardware device function supports MSI by indicating the
-MSI/MSI-X capability structure on its PCI capability list. By
-default, this capability structure will not be initialized by
-the kernel to enable MSI during the system boot. In other words,
-the device function is running on its default pin assertion mode.
-Note that in many cases the hardware supporting MSI have bugs,
-which may result in system hangs. The software driver of specific
-MSI-capable hardware is responsible for deciding whether to call
-pci_enable_msi or not. A return of zero indicates the kernel
-successfully initialized the MSI/MSI-X capability structure of the
-device function. The device function is now running on MSI/MSI-X mode.
-
-5.6 How to tell whether MSI/MSI-X is enabled on device function
-
-At the driver level, a return of zero from the function call of
-pci_enable_msi()/pci_enable_msix() indicates to a device driver that
-its device function is initialized successfully and ready to run in
-MSI/MSI-X mode.
-
-At the user level, users can use the command 'cat /proc/interrupts'
-to display the vectors allocated for devices and their interrupt
-MSI/MSI-X modes ("PCI-MSI"/"PCI-MSI-X"). Below shows MSI mode is
-enabled on a SCSI Adaptec 39320D Ultra320 controller.
-
-           CPU0       CPU1
-  0:     324639          0    IO-APIC-edge  timer
-  1:       1186          0    IO-APIC-edge  i8042
-  2:          0          0          XT-PIC  cascade
- 12:       2797          0    IO-APIC-edge  i8042
- 14:       6543          0    IO-APIC-edge  ide0
- 15:          1          0    IO-APIC-edge  ide1
-169:          0          0   IO-APIC-level  uhci-hcd
-185:          0          0   IO-APIC-level  uhci-hcd
-193:        138         10         PCI-MSI  aic79xx
-201:         30          0         PCI-MSI  aic79xx
-225:         30          0   IO-APIC-level  aic7xxx
-233:         30          0   IO-APIC-level  aic7xxx
-NMI:          0          0
-LOC:     324553     325068
-ERR:          0
-MIS:          0
-
-6. MSI quirks
-
-Several PCI chipsets or devices are known to not support MSI.
-The PCI stack provides 3 possible levels of MSI disabling:
-* on a single device
-* on all devices behind a specific bridge
-* globally
-
-6.1. Disabling MSI on a single device
-
-Under some circumstances it might be required to disable MSI on a
-single device.  This may be achieved by either not calling pci_enable_msi()
-or all, or setting the pci_dev->no_msi flag before (most of the time
-in a quirk).
-
-6.2. Disabling MSI below a bridge
-
-The vast majority of MSI quirks are required by PCI bridges not
-being able to route MSI between busses. In this case, MSI have to be
-disabled on all devices behind this bridge. It is achieves by setting
-the PCI_BUS_FLAGS_NO_MSI flag in the pci_bus->bus_flags of the bridge
-subordinate bus. There is no need to set the same flag on bridges that
-are below the broken bridge. When pci_enable_msi() is called to enable
-MSI on a device, pci_msi_supported() takes care of checking the NO_MSI
-flag in all parent busses of the device.
-
-Some bridges actually support dynamic MSI support enabling/disabling
-by changing some bits in their PCI configuration space (especially
-the Hypertransport chipsets such as the nVidia nForce and Serverworks
-HT2000). It may then be required to update the NO_MSI flag on the
-corresponding devices in the sysfs hierarchy. To enable MSI support
-on device "0000:00:0e", do:
-
-	echo 1 > /sys/bus/pci/devices/0000:00:0e/msi_bus
-
-To disable MSI support, echo 0 instead of 1. Note that it should be
-used with caution since changing this value might break interrupts.
-
-6.3. Disabling MSI globally
-
-Some extreme cases may require to disable MSI globally on the system.
-For now, the only known case is a Serverworks PCI-X chipsets (MSI are
-not supported on several busses that are not all connected to the
-chipset in the Linux PCI hierarchy). In the vast majority of other
-cases, disabling only behind a specific bridge is enough.
-
-For debugging purpose, the user may also pass pci=nomsi on the kernel
-command-line to explicitly disable MSI globally. But, once the appro-
-priate quirks are added to the kernel, this option should not be
-required anymore.
-
-6.4. Finding why MSI cannot be enabled on a device
-
-Assuming that MSI are not enabled on a device, you should look at
-dmesg to find messages that quirks may output when disabling MSI
-on some devices, some bridges or even globally.
-Then, lspci -t gives the list of bridges above a device. Reading
-/sys/bus/pci/devices/0000:00:0e/msi_bus will tell you whether MSI
-are enabled (1) or disabled (0). In 0 is found in a single bridge
-msi_bus file above the device, MSI cannot be enabled.
-
-7. FAQ
-
-Q1. Are there any limitations on using the MSI?
-
-A1. If the PCI device supports MSI and conforms to the
-specification and the platform supports the APIC local bus,
-then using MSI should work.
-
-Q2. Will it work on all the Pentium processors (P3, P4, Xeon,
-AMD processors)? In P3 IPI's are transmitted on the APIC local
-bus and in P4 and Xeon they are transmitted on the system
-bus. Are there any implications with this?
-
-A2. MSI support enables a PCI device sending an inbound
-memory write (0xfeexxxxx as target address) on its PCI bus
-directly to the FSB. Since the message address has a
-redirection hint bit cleared, it should work.
-
-Q3. The target address 0xfeexxxxx will be translated by the
-Host Bridge into an interrupt message. Are there any
-limitations on the chipsets such as Intel 8xx, Intel e7xxx,
-or VIA?
-
-A3. If these chipsets support an inbound memory write with
-target address set as 0xfeexxxxx, as conformed to PCI
-specification 2.3 or latest, then it should work.
-
-Q4. From the driver point of view, if the MSI is lost because
-of errors occurring during inbound memory write, then it may
-wait forever. Is there a mechanism for it to recover?
-
-A4. Since the target of the transaction is an inbound memory
-write, all transaction termination conditions (Retry,
-Master-Abort, Target-Abort, or normal completion) are
-supported. A device sending an MSI must abide by all the PCI
-rules and conditions regarding that inbound memory write. So,
-if a retry is signaled it must retry, etc... We believe that
-the recommendation for Abort is also a retry (refer to PCI
-specification 2.3 or latest).
+This API should be used to undo the effect of pci_enable_msix().  It frees
+the previously allocated message signaled interrupts.  The interrupts may
+subsequently be assigned to another device, so drivers should not cache
+the value of the 'vector' elements over a call to pci_disable_msix().
+
+A device driver must always call free_irq() on the interrupt(s)
+for which it has called request_irq() before calling this function.
+Failure to do so will result in a BUG_ON(), the device will be left with
+MSI enabled and will leak its vector.
+
+4.3.3 The MSI-X Table
+
+The MSI-X capability specifies a BAR and offset within that BAR for the
+MSI-X Table.  This address is mapped by the PCI subsystem, and should not
+be accessed directly by the device driver.  If the driver wishes to
+mask or unmask an interrupt, it should call disable_irq() / enable_irq().
+
+4.4 Handling devices implementing both MSI and MSI-X capabilities
+
+If a device implements both MSI and MSI-X capabilities, it can
+run in either MSI mode or MSI-X mode but not both simultaneously.
+This is a requirement of the PCI spec, and it is enforced by the
+PCI layer.  Calling pci_enable_msi() when MSI-X is already enabled or
+pci_enable_msix() when MSI is already enabled will result in an error.
+If a device driver wishes to switch between MSI and MSI-X at runtime,
+it must first quiesce the device, then switch it back to pin-interrupt
+mode, before calling pci_enable_msi() or pci_enable_msix() and resuming
+operation.  This is not expected to be a common operation but may be
+useful for debugging or testing during development.
+
+4.5 Considerations when using MSIs
+
+4.5.1 Choosing between MSI-X and MSI
+
+If your device supports both MSI-X and MSI capabilities, you should use
+the MSI-X facilities in preference to the MSI facilities.  As mentioned
+above, MSI-X supports any number of interrupts between 1 and 2048.
+In constrast, MSI is restricted to a maximum of 32 interrupts (and
+must be a power of two).  In addition, the MSI interrupt vectors must
+be allocated consecutively, so the system may not be able to allocate
+as many vectors for MSI as it could for MSI-X.  On some platforms, MSI
+interrupts must all be targetted at the same set of CPUs whereas MSI-X
+interrupts can all be targetted at different CPUs.
+
+4.5.2 Spinlocks
+
+Most device drivers have a per-device spinlock which is taken in the
+interrupt handler.  With pin-based interrupts or a single MSI, it is not
+necessary to disable interrupts (Linux guarantees the same interrupt will
+not be re-entered).  If a device uses multiple interrupts, the driver
+must disable interrupts while the lock is held.  If the device sends
+a different interrupt, the driver will deadlock trying to recursively
+acquire the spinlock.
+
+There are two solutions.  The first is to take the lock with
+spin_lock_irqsave() or spin_lock_irq() (see
+Documentation/DocBook/kernel-locking).  The second is to specify
+IRQF_DISABLED to request_irq() so that the kernel runs the entire
+interrupt routine with interrupts disabled.
+
+If your MSI interrupt routine does not hold the lock for the whole time
+it is running, the first solution may be best.  The second solution is
+normally preferred as it avoids making two transitions from interrupt
+disabled to enabled and back again.
+
+4.6 How to tell whether MSI/MSI-X is enabled on a device
+
+Using 'lspci -v' (as root) may show some devices with "MSI", "Message
+Signalled Interrupts" or "MSI-X" capabilities.  Each of these capabilities
+has an 'Enable' flag which will be followed with either "+" (enabled)
+or "-" (disabled).
+
+
+5. MSI quirks
+
+Several PCI chipsets or devices are known not to support MSIs.
+The PCI stack provides three ways to disable MSIs:
+
+1. globally
+2. on all devices behind a specific bridge
+3. on a single device
+
+5.1. Disabling MSIs globally
+
+Some host chipsets simply don't support MSIs properly.  If we're
+lucky, the manufacturer knows this and has indicated it in the ACPI
+FADT table.  In this case, Linux will automatically disable MSIs.
+Some boards don't include this information in the table and so we have
+to detect them ourselves.  The complete list of these is found near the
+quirk_disable_all_msi() function in drivers/pci/quirks.c.
+
+If you have a board which has problems with MSIs, you can pass pci=nomsi
+on the kernel command line to disable MSIs on all devices.  It would be
+in your best interests to report the problem to linux-pci@vger.kernel.org
+including a full 'lspci -v' so we can add the quirks to the kernel.
+
+5.2. Disabling MSIs below a bridge
+
+Some PCI bridges are not able to route MSIs between busses properly.
+In this case, MSIs must be disabled on all devices behind the bridge.
+
+Some bridges allow you to enable MSIs by changing some bits in their
+PCI configuration space (especially the Hypertransport chipsets such
+as the nVidia nForce and Serverworks HT2000).  As with host chipsets,
+Linux mostly knows about them and automatically enables MSIs if it can.
+If you have a bridge which Linux doesn't yet know about, you can enable
+MSIs in configuration space using whatever method you know works, then
+enable MSIs on that bridge by doing:
+
+       echo 1 > /sys/bus/pci/devices/$bridge/msi_bus
+
+where $bridge is the PCI address of the bridge you've enabled (eg
+0000:00:0e.0).
+
+To disable MSIs, echo 0 instead of 1.  Changing this value should be
+done with caution as it can break interrupt handling for all devices
+below this bridge.
+
+Again, please notify linux-pci@vger.kernel.org of any bridges that need
+special handling.
+
+5.3. Disabling MSIs on a single device
+
+Some devices are known to have faulty MSI implementations.  Usually this
+is handled in the individual device driver but occasionally it's necessary
+to handle this with a quirk.  Some drivers have an option to disable use
+of MSI.  While this is a convenient workaround for the driver author,
+it is not good practise, and should not be emulated.
+
+5.4. Finding why MSIs are disabled on a device
+
+From the above three sections, you can see that there are many reasons
+why MSIs may not be enabled for a given device.  Your first step should
+be to examine your dmesg carefully to determine whether MSIs are enabled
+for your machine.  You should also check your .config to be sure you
+have enabled CONFIG_PCI_MSI.
+
+Then, 'lspci -t' gives the list of bridges above a device.  Reading
+/sys/bus/pci/devices/*/msi_bus will tell you whether MSI are enabled (1)
+or disabled (0).  If 0 is found in any of the msi_bus files belonging
+to bridges between the PCI root and the device, MSIs are disabled.
+
+It is also worth checking the device driver to see whether it supports MSIs.
+For example, it may contain calls to pci_enable_msi(), pci_enable_msix() or
+pci_enable_msi_block().

Documentation/PCI/pci-iov-howto.txt

@@ -0,0 +1,99 @@
+		PCI Express I/O Virtualization Howto
+		Copyright (C) 2009 Intel Corporation
+		    Yu Zhao <yu.zhao@intel.com>
+
+
+1. Overview
+
+1.1 What is SR-IOV
+
+Single Root I/O Virtualization (SR-IOV) is a PCI Express Extended
+capability which makes one physical device appear as multiple virtual
+devices. The physical device is referred to as Physical Function (PF)
+while the virtual devices are referred to as Virtual Functions (VF).
+Allocation of the VF can be dynamically controlled by the PF via
+registers encapsulated in the capability. By default, this feature is
+not enabled and the PF behaves as traditional PCIe device. Once it's
+turned on, each VF's PCI configuration space can be accessed by its own
+Bus, Device and Function Number (Routing ID). And each VF also has PCI
+Memory Space, which is used to map its register set. VF device driver
+operates on the register set so it can be functional and appear as a
+real existing PCI device.
+
+2. User Guide
+
+2.1 How can I enable SR-IOV capability
+
+The device driver (PF driver) will control the enabling and disabling
+of the capability via API provided by SR-IOV core. If the hardware
+has SR-IOV capability, loading its PF driver would enable it and all
+VFs associated with the PF.
+
+2.2 How can I use the Virtual Functions
+
+The VF is treated as hot-plugged PCI devices in the kernel, so they
+should be able to work in the same way as real PCI devices. The VF
+requires device driver that is same as a normal PCI device's.
+
+3. Developer Guide
+
+3.1 SR-IOV API
+
+To enable SR-IOV capability:
+	int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn);
+	'nr_virtfn' is number of VFs to be enabled.
+
+To disable SR-IOV capability:
+	void pci_disable_sriov(struct pci_dev *dev);
+
+To notify SR-IOV core of Virtual Function Migration:
+	irqreturn_t pci_sriov_migration(struct pci_dev *dev);
+
+3.2 Usage example
+
+Following piece of code illustrates the usage of the SR-IOV API.
+
+static int __devinit dev_probe(struct pci_dev *dev, const struct pci_device_id *id)
+{
+	pci_enable_sriov(dev, NR_VIRTFN);
+
+	...
+
+	return 0;
+}
+
+static void __devexit dev_remove(struct pci_dev *dev)
+{
+	pci_disable_sriov(dev);
+
+	...
+}
+
+static int dev_suspend(struct pci_dev *dev, pm_message_t state)
+{
+	...
+
+	return 0;
+}
+
+static int dev_resume(struct pci_dev *dev)
+{
+	...
+
+	return 0;
+}
+
+static void dev_shutdown(struct pci_dev *dev)
+{
+	...
+}
+
+static struct pci_driver dev_driver = {
+	.name =		"SR-IOV Physical Function driver",
+	.id_table =	dev_id_table,
+	.probe =	dev_probe,
+	.remove =	__devexit_p(dev_remove),
+	.suspend =	dev_suspend,
+	.resume =	dev_resume,
+	.shutdown =	dev_shutdown,
+};

Documentation/RCU/listRCU.txt

@@ -118,7 +118,7 @@ Following are the RCU equivalents for these two functions:
 		list_for_each_entry(e, list, list) {
 			if (!audit_compare_rule(rule, &e->rule)) {
 				list_del_rcu(&e->list);
-				call_rcu(&e->rcu, audit_free_rule, e);
+				call_rcu(&e->rcu, audit_free_rule);
 				return 0;
 			}
 		}
@@ -206,7 +206,7 @@ RCU ("read-copy update") its name.  The RCU code is as follows:
 				ne->rule.action = newaction;
 				ne->rule.file_count = newfield_count;
 				list_replace_rcu(e, ne);
-				call_rcu(&e->rcu, audit_free_rule, e);
+				call_rcu(&e->rcu, audit_free_rule);
 				return 0;
 			}
 		}
@@ -283,7 +283,7 @@ flag under the spinlock as follows:
 				list_del_rcu(&e->list);
 				e->deleted = 1;
 				spin_unlock(&e->lock);
-				call_rcu(&e->rcu, audit_free_rule, e);
+				call_rcu(&e->rcu, audit_free_rule);
 				return 0;
 			}
 		}

Documentation/RCU/rcu.txt

@@ -81,7 +81,7 @@ o	I hear that RCU needs work in order to support realtime kernels?
 	This work is largely completed.  Realtime-friendly RCU can be
 	enabled via the CONFIG_PREEMPT_RCU kernel configuration parameter.
 	However, work is in progress for enabling priority boosting of
-	preempted RCU read-side critical sections.This is needed if you
+	preempted RCU read-side critical sections.  This is needed if you
 	have CPU-bound realtime threads.
 
 o	Where can I find more information on RCU?

Documentation/RCU/rculist_nulls.txt

@@ -21,7 +21,7 @@ if (obj) {
   /*
    * Because a writer could delete object, and a writer could
    * reuse these object before the RCU grace period, we
-   * must check key after geting the reference on object
+   * must check key after getting the reference on object
    */
   if (obj->key != key) { // not the object we expected
      put_ref(obj);
@@ -117,7 +117,7 @@ a race (some writer did a delete and/or a move of an object
 to another chain) checking the final 'nulls' value if
 the lookup met the end of chain. If final 'nulls' value
 is not the slot number, then we must restart the lookup at
-the begining. If the object was moved to same chain,
+the beginning. If the object was moved to the same chain,
 then the reader doesnt care : It might eventually
 scan the list again without harm.
 

Documentation/block/biodoc.txt

@@ -1040,23 +1040,21 @@ Front merges are handled by the binary trees in AS and deadline schedulers.
 iii. Plugging the queue to batch requests in anticipation of opportunities for
      merge/sort optimizations
 
-This is just the same as in 2.4 so far, though per-device unplugging
-support is anticipated for 2.5. Also with a priority-based i/o scheduler,
-such decisions could be based on request priorities.
-
 Plugging is an approach that the current i/o scheduling algorithm resorts to so
 that it collects up enough requests in the queue to be able to take
 advantage of the sorting/merging logic in the elevator. If the
 queue is empty when a request comes in, then it plugs the request queue
-(sort of like plugging the bottom of a vessel to get fluid to build up)
+(sort of like plugging the bath tub of a vessel to get fluid to build up)
 till it fills up with a few more requests, before starting to service
 the requests. This provides an opportunity to merge/sort the requests before
 passing them down to the device. There are various conditions when the queue is
 unplugged (to open up the flow again), either through a scheduled task or
 could be on demand. For example wait_on_buffer sets the unplugging going
-(by running tq_disk) so the read gets satisfied soon. So in the read case,
-the queue gets explicitly unplugged as part of waiting for completion,
-in fact all queues get unplugged as a side-effect.
+through sync_buffer() running blk_run_address_space(mapping). Or the caller
+can do it explicity through blk_unplug(bdev). So in the read case,
+the queue gets explicitly unplugged as part of waiting for completion on that
+buffer. For page driven IO, the address space ->sync_page() takes care of
+doing the blk_run_address_space().
 
 Aside:
   This is kind of controversial territory, as it's not clear if plugging is
@@ -1067,11 +1065,6 @@ Aside:
   multi-page bios being queued in one shot, we may not need to wait to merge
   a big request from the broken up pieces coming by.
 
-  Per-queue granularity unplugging (still a Todo) may help reduce some of the
-  concerns with just a single tq_disk flush approach. Something like
-  blk_kick_queue() to unplug a specific queue (right away ?)
-  or optionally, all queues, is in the plan.
-
 4.4 I/O contexts
 I/O contexts provide a dynamically allocated per process data area. They may
 be used in I/O schedulers, and in the block layer (could be used for IO statis,

Documentation/blockdev/00-INDEX

@@ -8,6 +8,8 @@ cpqarray.txt
 	- info on using Compaq's SMART2 Intelligent Disk Array Controllers.
 floppy.txt
 	- notes and driver options for the floppy disk driver.
+mflash.txt
+	- info on mGine m(g)flash driver for linux.
 nbd.txt
 	- info on a TCP implementation of a network block device.
 paride.txt

Documentation/blockdev/mflash.txt

@@ -0,0 +1,84 @@
+This document describes m[g]flash support in linux.
+
+Contents
+  1. Overview
+  2. Reserved area configuration
+  3. Example of mflash platform driver registration
+
+1. Overview
+
+Mflash and gflash are embedded flash drive. The only difference is mflash is
+MCP(Multi Chip Package) device. These two device operate exactly same way.
+So the rest mflash repersents mflash and gflash altogether.
+
+Internally, mflash has nand flash and other hardware logics and supports
+2 different operation (ATA, IO) modes. ATA mode doesn't need any new
+driver and currently works well under standard IDE subsystem. Actually it's
+one chip SSD. IO mode is ATA-like custom mode for the host that doesn't have
+IDE interface.
+
+Followings are brief descriptions about IO mode.
+A. IO mode based on ATA protocol and uses some custom command. (read confirm,
+write confirm)
+B. IO mode uses SRAM bus interface.
+C. IO mode supports 4kB boot area, so host can boot from mflash.
+
+2. Reserved area configuration
+If host boot from mflash, usually needs raw area for boot loader image. All of
+the mflash's block device operation will be taken this value as start offset.
+Note that boot loader's size of reserved area and kernel configuration value
+must be same.
+
+3. Example of mflash platform driver registration
+Working mflash is very straight forward. Adding platform device stuff to board
+configuration file is all. Here is some pseudo example.
+
+static struct mg_drv_data mflash_drv_data = {
+	/* If you want to polling driver set to 1 */
+	.use_polling = 0,
+	/* device attribution */
+	.dev_attr = MG_BOOT_DEV
+};
+
+static struct resource mg_mflash_rsc[] = {
+	/* Base address of mflash */
+	[0] = {
+		.start = 0x08000000,
+		.end = 0x08000000 + SZ_64K - 1,
+		.flags = IORESOURCE_MEM
+	},
+	/* mflash interrupt pin */
+	[1] = {
+		.start = IRQ_GPIO(84),
+		.end = IRQ_GPIO(84),
+		.flags = IORESOURCE_IRQ
+	},
+	/* mflash reset pin */
+	[2] = {
+		.start = 43,
+		.end = 43,
+		.name = MG_RST_PIN,
+		.flags = IORESOURCE_IO
+	},
+	/* mflash reset-out pin
+	 * If you use mflash as storage device (i.e. other than MG_BOOT_DEV),
+	 * should assign this */
+	[3] = {
+		.start = 51,
+		.end = 51,
+		.name = MG_RSTOUT_PIN,
+		.flags = IORESOURCE_IO
+	}
+};
+
+static struct platform_device mflash_dev = {
+	.name = MG_DEV_NAME,
+	.id = -1,
+	.dev = {
+		.platform_data = &mflash_drv_data,
+	},
+	.num_resources = ARRAY_SIZE(mg_mflash_rsc),
+	.resource = mg_mflash_rsc
+};
+
+platform_device_register(&mflash_dev);

Documentation/cgroups/00-INDEX

@@ -0,0 +1,18 @@
+00-INDEX
+	- this file
+cgroups.txt
+	- Control Groups definition, implementation details, examples and API.
+cpuacct.txt
+	- CPU Accounting Controller; account CPU usage for groups of tasks.
+cpusets.txt
+	- documents the cpusets feature; assign CPUs and Mem to a set of tasks.
+devices.txt
+	- Device Whitelist Controller; description, interface and security.
+freezer-subsystem.txt
+	- checkpointing; rationale to not use signals, interface.
+memcg_test.txt
+	- Memory Resource Controller; implementation details.
+memory.txt
+	- Memory Resource Controller; design, accounting, interface, testing.
+resource_counter.txt
+	- Resource Counter API.

Documentation/cgroups/cgroups.txt

@@ -56,7 +56,7 @@ hierarchy, and a set of subsystems; each subsystem has system-specific
 state attached to each cgroup in the hierarchy.  Each hierarchy has
 an instance of the cgroup virtual filesystem associated with it.
 
-At any one time there may be multiple active hierachies of task
+At any one time there may be multiple active hierarchies of task
 cgroups. Each hierarchy is a partition of all tasks in the system.
 
 User level code may create and destroy cgroups by name in an
@@ -124,10 +124,10 @@ following lines:
                                / \
                        Prof (15%) students (5%)
 
-Browsers like firefox/lynx go into the WWW network class, while (k)nfsd go
+Browsers like Firefox/Lynx go into the WWW network class, while (k)nfsd go
 into NFS network class.
 
-At the same time firefox/lynx will share an appropriate CPU/Memory class
+At the same time Firefox/Lynx will share an appropriate CPU/Memory class
 depending on who launched it (prof/student).
 
 With the ability to classify tasks differently for different resources
@@ -325,7 +325,7 @@ and then start a subshell 'sh' in that cgroup:
 Creating, modifying, using the cgroups can be done through the cgroup
 virtual filesystem.
 
-To mount a cgroup hierarchy will all available subsystems, type:
+To mount a cgroup hierarchy with all available subsystems, type:
 # mount -t cgroup xxx /dev/cgroup
 
 The "xxx" is not interpreted by the cgroup code, but will appear in
@@ -333,12 +333,23 @@ The "xxx" is not interpreted by the cgroup code, but will appear in
 
 To mount a cgroup hierarchy with just the cpuset and numtasks
 subsystems, type:
-# mount -t cgroup -o cpuset,numtasks hier1 /dev/cgroup
+# mount -t cgroup -o cpuset,memory hier1 /dev/cgroup
 
 To change the set of subsystems bound to a mounted hierarchy, just
 remount with different options:
+# mount -o remount,cpuset,ns hier1 /dev/cgroup
 
-# mount -o remount,cpuset,ns  /dev/cgroup
+Now memory is removed from the hierarchy and ns is added.
+
+Note this will add ns to the hierarchy but won't remove memory or
+cpuset, because the new options are appended to the old ones:
+# mount -o remount,ns /dev/cgroup
+
+To Specify a hierarchy's release_agent:
+# mount -t cgroup -o cpuset,release_agent="/sbin/cpuset_release_agent" \
+  xxx /dev/cgroup
+
+Note that specifying 'release_agent' more than once will return failure.
 
 Note that changing the set of subsystems is currently only supported
 when the hierarchy consists of a single (root) cgroup. Supporting
@@ -349,6 +360,11 @@ Then under /dev/cgroup you can find a tree that corresponds to the
 tree of the cgroups in the system. For instance, /dev/cgroup
 is the cgroup that holds the whole system.
 
+If you want to change the value of release_agent:
+# echo "/sbin/new_release_agent" > /dev/cgroup/release_agent
+
+It can also be changed via remount.
+
 If you want to create a new cgroup under /dev/cgroup:
 # cd /dev/cgroup
 # mkdir my_cgroup
@@ -476,11 +492,13 @@ cgroup->parent is still valid. (Note - can also be called for a
 newly-created cgroup if an error occurs after this subsystem's
 create() method has been called for the new cgroup).
 
-void pre_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp);
+int pre_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp);
 
 Called before checking the reference count on each subsystem. This may
 be useful for subsystems which have some extra references even if
-there are not tasks in the cgroup.
+there are not tasks in the cgroup. If pre_destroy() returns error code,
+rmdir() will fail with it. From this behavior, pre_destroy() can be
+called multiple times against a cgroup.
 
 int can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
 	       struct task_struct *task)
@@ -521,7 +539,7 @@ always handled well.
 void post_clone(struct cgroup_subsys *ss, struct cgroup *cgrp)
 (cgroup_mutex held by caller)
 
-Called at the end of cgroup_clone() to do any paramater
+Called at the end of cgroup_clone() to do any parameter
 initialization which might be required before a task could attach.  For
 example in cpusets, no task may attach before 'cpus' and 'mems' are set
 up.

Documentation/cgroups/cpuacct.txt

@@ -30,3 +30,21 @@ The above steps create a new group g1 and move the current shell
 process (bash) into it. CPU time consumed by this bash and its children
 can be obtained from g1/cpuacct.usage and the same is accumulated in
 /cgroups/cpuacct.usage also.
+
+cpuacct.stat file lists a few statistics which further divide the
+CPU time obtained by the cgroup into user and system times. Currently
+the following statistics are supported:
+
+user: Time spent by tasks of the cgroup in user mode.
+system: Time spent by tasks of the cgroup in kernel mode.
+
+user and system are in USER_HZ unit.
+
+cpuacct controller uses percpu_counter interface to collect user and
+system times. This has two side effects:
+
+- It is theoretically possible to see wrong values for user and system times.
+  This is because percpu_counter_read() on 32bit systems isn't safe
+  against concurrent writes.
+- It is possible to see slightly outdated values for user and system times
+  due to the batch processing nature of percpu_counter.

Documentation/cgroups/cpusets.txt

@@ -131,7 +131,7 @@ Cpusets extends these two mechanisms as follows:
  - The hierarchy of cpusets can be mounted at /dev/cpuset, for
    browsing and manipulation from user space.
  - A cpuset may be marked exclusive, which ensures that no other
-   cpuset (except direct ancestors and descendents) may contain
+   cpuset (except direct ancestors and descendants) may contain
    any overlapping CPUs or Memory Nodes.
  - You can list all the tasks (by pid) attached to any cpuset.
 
@@ -226,7 +226,7 @@ nodes with memory--using the cpuset_track_online_nodes() hook.
 --------------------------------
 
 If a cpuset is cpu or mem exclusive, no other cpuset, other than
-a direct ancestor or descendent, may share any of the same CPUs or
+a direct ancestor or descendant, may share any of the same CPUs or
 Memory Nodes.
 
 A cpuset that is mem_exclusive *or* mem_hardwall is "hardwalled",
@@ -427,7 +427,7 @@ child cpusets have this flag enabled.
 When doing this, you don't usually want to leave any unpinned tasks in
 the top cpuset that might use non-trivial amounts of CPU, as such tasks
 may be artificially constrained to some subset of CPUs, depending on
-the particulars of this flag setting in descendent cpusets.  Even if
+the particulars of this flag setting in descendant cpusets.  Even if
 such a task could use spare CPU cycles in some other CPUs, the kernel
 scheduler might not consider the possibility of load balancing that
 task to that underused CPU.
@@ -531,9 +531,9 @@ be idle.
 
 Of course it takes some searching cost to find movable tasks and/or
 idle CPUs, the scheduler might not search all CPUs in the domain
-everytime.  In fact, in some architectures, the searching ranges on
+every time.  In fact, in some architectures, the searching ranges on
 events are limited in the same socket or node where the CPU locates,
-while the load balance on tick searchs all.
+while the load balance on tick searches all.
 
 For example, assume CPU Z is relatively far from CPU X.  Even if CPU Z
 is idle while CPU X and the siblings are busy, scheduler can't migrate
@@ -601,7 +601,7 @@ its new cpuset, then the task will continue to use whatever subset
 of MPOL_BIND nodes are still allowed in the new cpuset.  If the task
 was using MPOL_BIND and now none of its MPOL_BIND nodes are allowed
 in the new cpuset, then the task will be essentially treated as if it
-was MPOL_BIND bound to the new cpuset (even though its numa placement,
+was MPOL_BIND bound to the new cpuset (even though its NUMA placement,
 as queried by get_mempolicy(), doesn't change).  If a task is moved
 from one cpuset to another, then the kernel will adjust the tasks
 memory placement, as above, the next time that the kernel attempts

Documentation/cgroups/devices.txt

@@ -42,7 +42,7 @@ suffice, but we can decide the best way to adequately restrict
 movement as people get some experience with this.  We may just want
 to require CAP_SYS_ADMIN, which at least is a separate bit from
 CAP_MKNOD.  We may want to just refuse moving to a cgroup which
-isn't a descendent of the current one.  Or we may want to use
+isn't a descendant of the current one.  Or we may want to use
 CAP_MAC_ADMIN, since we really are trying to lock down root.
 
 CAP_SYS_ADMIN is needed to modify the whitelist or move another

Documentation/cgroups/memcg_test.txt

@@ -1,5 +1,5 @@
 Memory Resource Controller(Memcg)  Implementation Memo.
-Last Updated: 2009/1/19
+Last Updated: 2009/1/20
 Base Kernel Version: based on 2.6.29-rc2.
 
 Because VM is getting complex (one of reasons is memcg...), memcg's behavior
@@ -356,7 +356,25 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y.
 	(Shell-B)
 	# move all tasks in /cgroup/test to /cgroup
 	# /sbin/swapoff -a
-	# rmdir /test/cgroup
+	# rmdir /cgroup/test
 	# kill malloc task.
 
 	Of course, tmpfs v.s. swapoff test should be tested, too.
+
+ 9.8 OOM-Killer
+	Out-of-memory caused by memcg's limit will kill tasks under
+	the memcg. When hierarchy is used, a task under hierarchy
+	will be killed by the kernel.
+	In this case, panic_on_oom shouldn't be invoked and tasks
+	in other groups shouldn't be killed.
+
+	It's not difficult to cause OOM under memcg as following.
+	Case A) when you can swapoff
+	#swapoff -a
+	#echo 50M > /memory.limit_in_bytes
+	run 51M of malloc
+
+	Case B) when you use mem+swap limitation.
+	#echo 50M > memory.limit_in_bytes
+	#echo 50M > memory.memsw.limit_in_bytes
+	run 51M of malloc

Documentation/cgroups/memory.txt

@@ -6,15 +6,14 @@ used here with the memory controller that is used in hardware.
 
 Salient features
 
-a. Enable control of both RSS (mapped) and Page Cache (unmapped) pages
+a. Enable control of Anonymous, Page Cache (mapped and unmapped) and
+   Swap Cache memory pages.
 b. The infrastructure allows easy addition of other types of memory to control
 c. Provides *zero overhead* for non memory controller users
 d. Provides a double LRU: global memory pressure causes reclaim from the
    global LRU; a cgroup on hitting a limit, reclaims from the per
    cgroup LRU
 
-NOTE: Swap Cache (unmapped) is not accounted now.
-
 Benefits and Purpose of the memory controller
 
 The memory controller isolates the memory behaviour of a group of tasks
@@ -290,34 +289,44 @@ will be charged as a new owner of it.
   moved to the parent. If you want to avoid that, force_empty will be useful.
 
 5.2 stat file
-  memory.stat file includes following statistics (now)
-	cache			- # of pages from page-cache and shmem.
-	rss			- # of pages from anonymous memory.
-	pgpgin			- # of event of charging
-	pgpgout			- # of event of uncharging
-	active_anon		- # of pages on active lru of anon, shmem.
-	inactive_anon 		- # of pages on active lru of anon, shmem
-	active_file		- # of pages on active lru of file-cache
-	inactive_file		- # of pages on inactive lru of file cache
-	unevictable		- # of pages cannot be reclaimed.(mlocked etc)
-
-	Below is depend on CONFIG_DEBUG_VM.
-	inactive_ratio		- VM inernal parameter. (see mm/page_alloc.c)
-	recent_rotated_anon	- VM internal parameter. (see mm/vmscan.c)
-	recent_rotated_file	- VM internal parameter. (see mm/vmscan.c)
-	recent_scanned_anon 	- VM internal parameter. (see mm/vmscan.c)
-	recent_scanned_file 	- VM internal parameter. (see mm/vmscan.c)
-
-  Memo:
+
+memory.stat file includes following statistics
+
+cache		- # of bytes of page cache memory.
+rss		- # of bytes of anonymous and swap cache memory.
+pgpgin		- # of pages paged in (equivalent to # of charging events).
+pgpgout		- # of pages paged out (equivalent to # of uncharging events).
+active_anon	- # of bytes of anonymous and  swap cache memory on active
+		  lru list.
+inactive_anon	- # of bytes of anonymous memory and swap cache memory on
+		  inactive lru list.
+active_file	- # of bytes of file-backed memory on active lru list.
+inactive_file	- # of bytes of file-backed memory on inactive lru list.
+unevictable	- # of bytes of memory that cannot be reclaimed (mlocked etc).
+
+The following additional stats are dependent on CONFIG_DEBUG_VM.
+
+inactive_ratio		- VM internal parameter. (see mm/page_alloc.c)
+recent_rotated_anon	- VM internal parameter. (see mm/vmscan.c)
+recent_rotated_file	- VM internal parameter. (see mm/vmscan.c)
+recent_scanned_anon	- VM internal parameter. (see mm/vmscan.c)
+recent_scanned_file	- VM internal parameter. (see mm/vmscan.c)
+
+Memo:
 	recent_rotated means recent frequency of lru rotation.
 	recent_scanned means recent # of scans to lru.
 	showing for better debug please see the code for meanings.
 
+Note:
+	Only anonymous and swap cache memory is listed as part of 'rss' stat.
+	This should not be confused with the true 'resident set size' or the
+	amount of physical memory used by the cgroup. Per-cgroup rss
+	accounting is not done yet.
 
 5.3 swappiness
   Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only.
 
-  Following cgroup's swapiness can't be changed.
+  Following cgroups' swapiness can't be changed.
   - root cgroup (uses /proc/sys/vm/swappiness).
   - a cgroup which uses hierarchy and it has child cgroup.
   - a cgroup which uses hierarchy and not the root of hierarchy.

Documentation/cgroups/resource_counter.txt

@@ -47,13 +47,18 @@ to work with it.
 
 2. Basic accounting routines
 
- a. void res_counter_init(struct res_counter *rc)
+ a. void res_counter_init(struct res_counter *rc,
+				struct res_counter *rc_parent)
 
  	Initializes the resource counter. As usual, should be the first
 	routine called for a new counter.
 
- b. int res_counter_charge[_locked]
-			(struct res_counter *rc, unsigned long val)
+	The struct res_counter *parent can be used to define a hierarchical
+	child -> parent relationship directly in the res_counter structure,
+	NULL can be used to define no relationship.
+
+ c. int res_counter_charge(struct res_counter *rc, unsigned long val,
+				struct res_counter **limit_fail_at)
 
 	When a resource is about to be allocated it has to be accounted
 	with the appropriate resource counter (controller should determine
@@ -67,15 +72,25 @@ to work with it.
 	  * if the charging is performed first, then it should be uncharged
 	    on error path (if the one is called).
 
- c. void res_counter_uncharge[_locked]
+	If the charging fails and a hierarchical dependency exists, the
+	limit_fail_at parameter is set to the particular res_counter element
+	where the charging failed.
+
+ d. int res_counter_charge_locked
+			(struct res_counter *rc, unsigned long val)
+
+	The same as res_counter_charge(), but it must not acquire/release the
+	res_counter->lock internally (it must be called with res_counter->lock
+	held).
+
+ e. void res_counter_uncharge[_locked]
 			(struct res_counter *rc, unsigned long val)
 
 	When a resource is released (freed) it should be de-accounted
 	from the resource counter it was accounted to.  This is called
 	"uncharging".
 
-    The _locked routines imply that the res_counter->lock is taken.
-
+	The _locked routines imply that the res_counter->lock is taken.
 
  2.1 Other accounting routines
 

Documentation/devices.txt

@@ -1,9 +1,9 @@
 
 		    LINUX ALLOCATED DEVICES (2.6+ version)
 
-	     Maintained by Torben Mathiasen <device@lanana.org>
+	     Maintained by Alan Cox <device@lanana.org>
 
-		      Last revised: 29 November 2006
+		      Last revised: 6th April 2009
 
 This list is the Linux Device List, the official registry of allocated
 device numbers and /dev directory nodes for the Linux operating
@@ -67,6 +67,11 @@ up to date.  Due to the number of registrations I have to maintain it
 in "batch mode", so there is likely additional registrations that
 haven't been listed yet.
 
+Fourth, remember that Linux now has extensive support for dynamic allocation
+of device numbering and can use sysfs and udev to handle the naming needs.
+There are still some exceptions in the serial and boot device area. Before
+asking for a device number make sure you actually need one.
+
 Finally, sometimes I have to play "namespace police."  Please don't be
 offended.  I often get submissions for /dev names that would be bound
 to cause conflicts down the road.  I am trying to avoid getting in a
@@ -101,7 +106,7 @@ Your cooperation is appreciated.
 		  0 = /dev/ram0		First RAM disk
 		  1 = /dev/ram1		Second RAM disk
 		    ...
-		250 = /dev/initrd	Initial RAM disk {2.6}
+		250 = /dev/initrd	Initial RAM disk
 
 		Older kernels had /dev/ramdisk (1, 1) here.
 		/dev/initrd refers to a RAM disk which was preloaded
@@ -340,7 +345,7 @@ Your cooperation is appreciated.
 		 14 = /dev/touchscreen/ucb1x00  UCB 1x00 touchscreen
 		 15 = /dev/touchscreen/mk712	MK712 touchscreen
 		128 = /dev/beep		Fancy beep device
-		129 = /dev/modreq	Kernel module load request {2.6}
+		129 =
 		130 = /dev/watchdog	Watchdog timer port
 		131 = /dev/temperature	Machine internal temperature
 		132 = /dev/hwtrap	Hardware fault trap
@@ -350,10 +355,10 @@ Your cooperation is appreciated.
 		139 = /dev/openprom	SPARC OpenBoot PROM
 		140 = /dev/relay8	Berkshire Products Octal relay card
 		141 = /dev/relay16	Berkshire Products ISO-16 relay card
-		142 = /dev/msr		x86 model-specific registers {2.6}
+		142 =
 		143 = /dev/pciconf	PCI configuration space
 		144 = /dev/nvram	Non-volatile configuration RAM
-		145 = /dev/hfmodem	Soundcard shortwave modem control {2.6}
+		145 = /dev/hfmodem	Soundcard shortwave modem control
 		146 = /dev/graphics	Linux/SGI graphics device
 		147 = /dev/opengl	Linux/SGI OpenGL pipe
 		148 = /dev/gfx		Linux/SGI graphics effects device
@@ -435,6 +440,9 @@ Your cooperation is appreciated.
 		228 = /dev/hpet		HPET driver
 		229 = /dev/fuse		Fuse (virtual filesystem in user-space)
 		230 = /dev/midishare	MidiShare driver
+		231 = /dev/snapshot	System memory snapshot device
+		232 = /dev/kvm		Kernel-based virtual machine (hardware virtualization extensions)
+		233 = /dev/kmview	View-OS A process with a view
 		240-254			Reserved for local use
 		255			Reserved for MISC_DYNAMIC_MINOR
 
@@ -466,10 +474,7 @@ Your cooperation is appreciated.
 		The device names specified are proposed -- if there
 		are "standard" names for these devices, please let me know.
 
- 12 block	MSCDEX CD-ROM callback support {2.6}
-		  0 = /dev/dos_cd0	First MSCDEX CD-ROM
-		  1 = /dev/dos_cd1	Second MSCDEX CD-ROM
-		    ...
+ 12 block
 
  13 char	Input core
 		  0 = /dev/input/js0	First joystick
@@ -498,7 +503,7 @@ Your cooperation is appreciated.
 		  2 = /dev/midi00	First MIDI port
 		  3 = /dev/dsp		Digital audio
 		  4 = /dev/audio	Sun-compatible digital audio
-		  6 = /dev/sndstat	Sound card status information {2.6}
+		  6 =
 		  7 = /dev/audioctl	SPARC audio control device
 		  8 = /dev/sequencer2	Sequencer -- alternate device
 		 16 = /dev/mixer1	Second soundcard mixer control
@@ -510,14 +515,7 @@ Your cooperation is appreciated.
 		 34 = /dev/midi02	Third MIDI port
 		 50 = /dev/midi03	Fourth MIDI port
 
- 14 block	BIOS harddrive callback support {2.6}
-		  0 = /dev/dos_hda	First BIOS harddrive whole disk
-		 64 = /dev/dos_hdb	Second BIOS harddrive whole disk
-		128 = /dev/dos_hdc	Third BIOS harddrive whole disk
-		192 = /dev/dos_hdd	Fourth BIOS harddrive whole disk
-
-		Partitions are handled in the same way as IDE disks
-		(see major number 3).
+ 14 block
 
  15 char	Joystick
 		  0 = /dev/js0		First analog joystick
@@ -535,14 +533,14 @@ Your cooperation is appreciated.
  16 block	GoldStar CD-ROM
 		  0 = /dev/gscd		GoldStar CD-ROM
 
- 17 char	Chase serial card
+ 17 char	OBSOLETE (was Chase serial card)
 		  0 = /dev/ttyH0	First Chase port
 		  1 = /dev/ttyH1	Second Chase port
 		    ...
  17 block	Optics Storage CD-ROM
 		  0 = /dev/optcd	Optics Storage CD-ROM
 
- 18 char	Chase serial card - alternate devices
+ 18 char	OBSOLETE (was Chase serial card - alternate devices)
 		  0 = /dev/cuh0		Callout device for ttyH0
 		  1 = /dev/cuh1		Callout device for ttyH1
 		    ...
@@ -644,8 +642,7 @@ Your cooperation is appreciated.
 		  2 = /dev/sbpcd2	Panasonic CD-ROM controller 0 unit 2
 		  3 = /dev/sbpcd3	Panasonic CD-ROM controller 0 unit 3
 
- 26 char	Quanta WinVision frame grabber {2.6}
-		  0 = /dev/wvisfgrab	Quanta WinVision frame grabber
+ 26 char
 
  26 block	Second Matsushita (Panasonic/SoundBlaster) CD-ROM
 		  0 = /dev/sbpcd4	Panasonic CD-ROM controller 1 unit 0
@@ -872,7 +869,7 @@ Your cooperation is appreciated.
 		and "user level packet I/O."  This board is also
 		accessible as a standard networking "eth" device.
 
- 38 block	Reserved for Linux/AP+
+ 38 block	OBSOLETE (was Linux/AP+)
 
  39 char	ML-16P experimental I/O board
 		  0 = /dev/ml16pa-a0	First card, first analog channel
@@ -892,29 +889,16 @@ Your cooperation is appreciated.
 		 50 = /dev/ml16pb-c1	Second card, second counter/timer
 		 51 = /dev/ml16pb-c2	Second card, third counter/timer
 		      ...
- 39 block	Reserved for Linux/AP+
+ 39 block
 
- 40 char	Matrox Meteor frame grabber {2.6}
-		  0 = /dev/mmetfgrab	Matrox Meteor frame grabber
+ 40 char
 
- 40 block	Syquest EZ135 parallel port removable drive
-		  0 = /dev/eza		Parallel EZ135 drive, whole disk
-
-		This device is obsolete and will be removed in a
-		future version of Linux.  It has been replaced with
-		the parallel port IDE disk driver at major number 45.
-		Partitions are handled in the same way as IDE disks
-		(see major number 3).
+ 40 block
 
  41 char	Yet Another Micro Monitor
 		  0 = /dev/yamm		Yet Another Micro Monitor
 
- 41 block	MicroSolutions BackPack parallel port CD-ROM
-		  0 = /dev/bpcd		BackPack CD-ROM
-
-		This device is obsolete and will be removed in a
-		future version of Linux.  It has been replaced with
-		the parallel port ATAPI CD-ROM driver at major number 46.
+ 41 block
 
  42 char	Demo/sample use
 
@@ -1681,13 +1665,7 @@ Your cooperation is appreciated.
 		disks (see major number 3) except that the limit on
 		partitions is 15.
 
- 93 char	IBM Smart Capture Card frame grabber {2.6}
-		  0 = /dev/iscc0	First Smart Capture Card
-		  1 = /dev/iscc1	Second Smart Capture Card
-		    ...
-		128 = /dev/isccctl0	First Smart Capture Card control
-		129 = /dev/isccctl1	Second Smart Capture Card control
-		    ...
+ 93 char
 
  93 block	NAND Flash Translation Layer filesystem
 		  0 = /dev/nftla	First NFTL layer
@@ -1695,10 +1673,7 @@ Your cooperation is appreciated.
 		    ...
 		240 = /dev/nftlp	16th NTFL layer
 
- 94 char	miroVIDEO DC10/30 capture/playback device {2.6}
-		  0 = /dev/dcxx0	First capture card
-		  1 = /dev/dcxx1	Second capture card
-		    ...
+ 94 char
 
  94 block	IBM S/390 DASD block storage
     		  0 = /dev/dasda First DASD device, major
@@ -1791,11 +1766,7 @@ Your cooperation is appreciated.
 		    ...
 		 15 = /dev/amiraid/ar?p15 15th partition
 
-102 char	Philips SAA5249 Teletext signal decoder {2.6}
-		  0 = /dev/tlk0		First Teletext decoder
-		  1 = /dev/tlk1		Second Teletext decoder
-		  2 = /dev/tlk2		Third Teletext decoder
-		  3 = /dev/tlk3		Fourth Teletext decoder
+102 char
 
 102 block	Compressed block device
 		  0 = /dev/cbd/a	First compressed block device, whole device
@@ -1916,10 +1887,7 @@ Your cooperation is appreciated.
 		DAC960 (see major number 48) except that the limit on
 		partitions is 15.
 
-111 char	Philips SAA7146-based audio/video card {2.6}
-		  0 = /dev/av0		First A/V card
-		  1 = /dev/av1		Second A/V card
-		    ...
+111 char
 
 111 block	Compaq Next Generation Drive Array, eighth controller
 		  0 = /dev/cciss/c7d0	First logical drive, whole disk
@@ -2079,8 +2047,8 @@ Your cooperation is appreciated.
 		    ...
 
 119 char	VMware virtual network control
-		  0 = /dev/vmnet0	1st virtual network
-		  1 = /dev/vmnet1	2nd virtual network
+		  0 = /dev/vnet0	1st virtual network
+		  1 = /dev/vnet1	2nd virtual network
 		    ...
 
 120-127 char	LOCAL/EXPERIMENTAL USE
@@ -2450,7 +2418,7 @@ Your cooperation is appreciated.
 		  2 = /dev/raw/raw2	Second raw I/O device
 		    ...
 
-163 char	UNASSIGNED (was Radio Tech BIM-XXX-RS232 radio modem - see 51)
+163 char
 
 164 char	Chase Research AT/PCI-Fast serial card
 		  0 = /dev/ttyCH0	AT/PCI-Fast board 0, port 0
@@ -2542,6 +2510,12 @@ Your cooperation is appreciated.
 		  1 = /dev/clanvi1	Second cLAN adapter
 		    ...
 
+179 block       MMC block devices
+		  0 = /dev/mmcblk0      First SD/MMC card
+		  1 = /dev/mmcblk0p1    First partition on first MMC card
+		  8 = /dev/mmcblk1      Second SD/MMC card
+		    ...
+
 179 char	CCube DVXChip-based PCI products
 		  0 = /dev/dvxirq0	First DVX device
 		  1 = /dev/dvxirq1	Second DVX device
@@ -2560,6 +2534,9 @@ Your cooperation is appreciated.
 		 96 = /dev/usb/hiddev0	1st USB HID device
 		    ...
 		111 = /dev/usb/hiddev15	16th USB HID device
+		112 = /dev/usb/auer0	1st auerswald ISDN device
+		    ...
+		127 = /dev/usb/auer15	16th auerswald ISDN device
 		128 = /dev/usb/brlvgr0	First Braille Voyager device
 		    ...
 		131 = /dev/usb/brlvgr3	Fourth Braille Voyager device
@@ -2810,6 +2787,20 @@ Your cooperation is appreciated.
 		    ...
 		 190 = /dev/ttyUL3		Xilinx uartlite - port 3
 		 191 = /dev/xvc0		Xen virtual console - port 0
+		 192 = /dev/ttyPZ0		pmac_zilog - port 0
+		    ...
+		 195 = /dev/ttyPZ3		pmac_zilog - port 3
+		 196 = /dev/ttyTX0		TX39/49 serial port 0
+		    ...
+		 204 = /dev/ttyTX7		TX39/49 serial port 7
+		 205 = /dev/ttySC0		SC26xx serial port 0
+		 206 = /dev/ttySC1		SC26xx serial port 1
+		 207 = /dev/ttySC2		SC26xx serial port 2
+		 208 = /dev/ttySC3		SC26xx serial port 3
+		 209 = /dev/ttyMAX0		MAX3100 serial port 0
+		 210 = /dev/ttyMAX1		MAX3100 serial port 1
+		 211 = /dev/ttyMAX2		MAX3100 serial port 2
+		 212 = /dev/ttyMAX3		MAX3100 serial port 3
 
 205 char	Low-density serial ports (alternate device)
 		  0 = /dev/culu0		Callout device for ttyLU0
@@ -3145,6 +3136,14 @@ Your cooperation is appreciated.
 		  1 = /dev/blockrom1	Second ROM card's translation layer interface
 		  ...
 
+259 block	Block Extended Major
+		  Used dynamically to hold additional partition minor
+		  numbers and allow large numbers of partitions per device
+
+259 char	FPGA configuration interfaces
+		  0 = /dev/icap0	First Xilinx internal configuration
+		  1 = /dev/icap1	Second Xilinx internal configuration
+
 260 char	OSD (Object-based-device) SCSI Device
 		  0 = /dev/osd0		First OSD Device
 		  1 = /dev/osd1		Second OSD Device

Documentation/driver-model/platform.txt

@@ -169,3 +169,62 @@ three different ways to find such a match:
       be probed later if another device registers.  (Which is OK, since
       this interface is only for use with non-hotpluggable devices.)
 
+
+Early Platform Devices and Drivers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The early platform interfaces provide platform data to platform device
+drivers early on during the system boot. The code is built on top of the
+early_param() command line parsing and can be executed very early on.
+
+Example: "earlyprintk" class early serial console in 6 steps
+
+1. Registering early platform device data
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The architecture code registers platform device data using the function
+early_platform_add_devices(). In the case of early serial console this
+should be hardware configuration for the serial port. Devices registered
+at this point will later on be matched against early platform drivers.
+
+2. Parsing kernel command line
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The architecture code calls parse_early_param() to parse the kernel
+command line. This will execute all matching early_param() callbacks.
+User specified early platform devices will be registered at this point.
+For the early serial console case the user can specify port on the
+kernel command line as "earlyprintk=serial.0" where "earlyprintk" is
+the class string, "serial" is the name of the platfrom driver and
+0 is the platform device id. If the id is -1 then the dot and the
+id can be omitted.
+
+3. Installing early platform drivers belonging to a certain class
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The architecture code may optionally force registration of all early
+platform drivers belonging to a certain class using the function
+early_platform_driver_register_all(). User specified devices from
+step 2 have priority over these. This step is omitted by the serial
+driver example since the early serial driver code should be disabled
+unless the user has specified port on the kernel command line.
+
+4. Early platform driver registration
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Compiled-in platform drivers making use of early_platform_init() are
+automatically registered during step 2 or 3. The serial driver example
+should use early_platform_init("earlyprintk", &platform_driver).
+
+5. Probing of early platform drivers belonging to a certain class
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The architecture code calls early_platform_driver_probe() to match
+registered early platform devices associated with a certain class with
+registered early platform drivers. Matched devices will get probed().
+This step can be executed at any point during the early boot. As soon
+as possible may be good for the serial port case.
+
+6. Inside the early platform driver probe()
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The driver code needs to take special care during early boot, especially
+when it comes to memory allocation and interrupt registration. The code
+in the probe() function can use is_early_platform_device() to check if
+it is called at early platform device or at the regular platform device
+time. The early serial driver performs register_console() at this point.
+
+For further information, see <linux/platform_device.h>.

Documentation/dvb/get_dvb_firmware

@@ -25,7 +25,7 @@ use IO::Handle;
 		"tda10046lifeview", "av7110", "dec2000t", "dec2540t",
 		"dec3000s", "vp7041", "dibusb", "nxt2002", "nxt2004",
 		"or51211", "or51132_qam", "or51132_vsb", "bluebird",
-		"opera1");
+		"opera1", "cx231xx", "cx18", "cx23885", "pvrusb2" );
 
 # Check args
 syntax() if (scalar(@ARGV) != 1);
@@ -37,8 +37,8 @@ for ($i=0; $i < scalar(@components); $i++) {
 	$outfile = eval($cid);
 	die $@ if $@;
 	print STDERR <<EOF;
-Firmware $outfile extracted successfully.
-Now copy it to either /usr/lib/hotplug/firmware or /lib/firmware
+Firmware(s) $outfile extracted successfully.
+Now copy it(they) to either /usr/lib/hotplug/firmware or /lib/firmware
 (depending on configuration of firmware hotplug).
 EOF
 	exit(0);
@@ -345,6 +345,85 @@ sub or51211 {
     $fwfile;
 }
 
+sub cx231xx {
+    my $fwfile = "v4l-cx231xx-avcore-01.fw";
+    my $url = "http://linuxtv.org/downloads/firmware/$fwfile";
+    my $hash = "7d3bb956dc9df0eafded2b56ba57cc42";
+
+    checkstandard();
+
+    wgetfile($fwfile, $url);
+    verify($fwfile, $hash);
+
+    $fwfile;
+}
+
+sub cx18 {
+    my $url = "http://linuxtv.org/downloads/firmware/";
+
+    my %files = (
+	'v4l-cx23418-apu.fw' => '588f081b562f5c653a3db1ad8f65939a',
+	'v4l-cx23418-cpu.fw' => 'b6c7ed64bc44b1a6e0840adaeac39d79',
+	'v4l-cx23418-dig.fw' => '95bc688d3e7599fd5800161e9971cc55',
+    );
+
+    checkstandard();
+
+    my $allfiles;
+    foreach my $fwfile (keys %files) {
+	wgetfile($fwfile, "$url/$fwfile");
+	verify($fwfile, $files{$fwfile});
+	$allfiles .= " $fwfile";
+    }
+
+    $allfiles =~ s/^\s//;
+
+    $allfiles;
+}
+
+sub cx23885 {
+    my $url = "http://linuxtv.org/downloads/firmware/";
+
+    my %files = (
+	'v4l-cx23885-avcore-01.fw' => 'a9f8f5d901a7fb42f552e1ee6384f3bb',
+	'v4l-cx23885-enc.fw'       => 'a9f8f5d901a7fb42f552e1ee6384f3bb',
+    );
+
+    checkstandard();
+
+    my $allfiles;
+    foreach my $fwfile (keys %files) {
+	wgetfile($fwfile, "$url/$fwfile");
+	verify($fwfile, $files{$fwfile});
+	$allfiles .= " $fwfile";
+    }
+
+    $allfiles =~ s/^\s//;
+
+    $allfiles;
+}
+
+sub pvrusb2 {
+    my $url = "http://linuxtv.org/downloads/firmware/";
+
+    my %files = (
+	'v4l-cx25840.fw'           => 'dadb79e9904fc8af96e8111d9cb59320',
+    );
+
+    checkstandard();
+
+    my $allfiles;
+    foreach my $fwfile (keys %files) {
+	wgetfile($fwfile, "$url/$fwfile");
+	verify($fwfile, $files{$fwfile});
+	$allfiles .= " $fwfile";
+    }
+
+    $allfiles =~ s/^\s//;
+
+    $allfiles;
+}
+
 sub or51132_qam {
     my $fwfile = "dvb-fe-or51132-qam.fw";
     my $url = "http://linuxtv.org/downloads/firmware/$fwfile";

Documentation/fb/00-INDEX

@@ -11,8 +11,6 @@ aty128fb.txt
 	- info on the ATI Rage128 frame buffer driver.
 cirrusfb.txt
 	- info on the driver for Cirrus Logic chipsets.
-cyblafb/
-	- directory with documentation files related to the cyblafb driver.
 deferred_io.txt
 	- an introduction to deferred IO.
 fbcon.txt

Documentation/fb/cyblafb/bugs

@@ -1,13 +0,0 @@
-Bugs
-====
-
-I currently don't know of any bug. Please do send reports to:
- - linux-fbdev-devel@lists.sourceforge.net
- - Knut_Petersen@t-online.de.
-
-
-Untested features
-=================
-
-All LCD stuff is untested. If it worked in tridentfb, it should work in
-cyblafb. Please test and report the results to Knut_Petersen@t-online.de.

Documentation/fb/cyblafb/credits

@@ -1,7 +0,0 @@
-Thanks to
-=========
-   * 	Alan Hourihane, for writing the X trident driver
-   *	Jani Monoses, for writing the tridentfb driver
-   *	Antonino A. Daplas, for review of the first published
-	version of cyblafb and some code
-   *	Jochen Hein, for testing and a helpfull bug report

Documentation/fb/cyblafb/documentation

@@ -1,17 +0,0 @@
-Available Documentation
-=======================
-
-Apollo PLE 133 Chipset VT8601A North Bridge Datasheet, Rev. 1.82, October 22,
-2001, available from VIA:
-
-	http://www.viavpsd.com/product/6/15/DS8601A182.pdf
-
-The datasheet is incomplete, some registers that need to be programmed are not
-explained at all and important bits are listed as "reserved". But you really
-need the datasheet to understand the code.  "p. xxx" comments refer to page
-numbers of this document.
-
-XFree/XOrg drivers are available and of good quality, looking at the code
-there is a good idea if the datasheet does not provide enough information
-or if the datasheet seems to be wrong.
-

Documentation/fb/cyblafb/fb.modes

@@ -1,154 +0,0 @@
-#
-#   Sample fb.modes file
-#
-#	Provides an incomplete list of working modes for
-#	the cyberblade/i1 graphics core.
-#
-#	The value 4294967256 is used instead of -40. Of course, -40 is not
-#	a really reasonable value, but chip design does not always follow
-#	logic. Believe me, it's ok, and it's the way the BIOS does it.
-#
-#	fbset requires 4294967256 in fb.modes and -40 as an argument to
-#	the -t parameter. That's also not too reasonable, and it might change
-#	in the future or might even be differt for your current version.
-#
-
-mode "640x480-50"
-    geometry 640 480 2048 4096 8
-    timings 47619 4294967256 24 17 0 216 3
-endmode
-
-mode "640x480-60"
-    geometry 640 480 2048 4096 8
-    timings 39682 4294967256 24 17 0 216 3
-endmode
-
-mode "640x480-70"
-    geometry 640 480 2048 4096 8
-    timings 34013 4294967256 24 17 0 216 3
-endmode
-
-mode "640x480-72"
-    geometry 640 480 2048 4096 8
-    timings 33068 4294967256 24 17 0 216 3
-endmode
-
-mode "640x480-75"
-    geometry 640 480 2048 4096 8
-    timings 31746 4294967256 24 17 0 216 3
-endmode
-
-mode "640x480-80"
-    geometry 640 480 2048 4096 8
-    timings 29761 4294967256 24 17 0 216 3
-endmode
-
-mode "640x480-85"
-    geometry 640 480 2048 4096 8
-    timings 28011 4294967256 24 17 0 216 3
-endmode
-
-mode "800x600-50"
-    geometry 800 600 2048 4096 8
-    timings 30303 96 24 14 0 136 11
-endmode
-
-mode "800x600-60"
-    geometry 800 600 2048 4096 8
-    timings 25252 96 24 14 0 136 11
-endmode
-
-mode "800x600-70"
-    geometry 800 600 2048 4096 8
-    timings 21645 96 24 14 0 136 11
-endmode
-
-mode "800x600-72"
-    geometry 800 600 2048 4096 8
-    timings 21043 96 24 14 0 136 11
-endmode
-
-mode "800x600-75"
-    geometry 800 600 2048 4096 8
-    timings 20202 96 24 14 0 136 11
-endmode
-
-mode "800x600-80"
-    geometry 800 600 2048 4096 8
-    timings 18939 96 24 14 0 136 11
-endmode
-
-mode "800x600-85"
-    geometry 800 600 2048 4096 8
-    timings 17825 96 24 14 0 136 11
-endmode
-
-mode "1024x768-50"
-    geometry 1024 768 2048 4096 8
-    timings 19054 144 24 29 0 120 3
-endmode
-
-mode "1024x768-60"
-    geometry 1024 768 2048 4096 8
-    timings 15880 144 24 29 0 120 3
-endmode
-
-mode "1024x768-70"
-    geometry 1024 768 2048 4096 8
-    timings 13610 144 24 29 0 120 3
-endmode
-
-mode "1024x768-72"
-    geometry 1024 768 2048 4096 8
-    timings 13232 144 24 29 0 120 3
-endmode
-
-mode "1024x768-75"
-    geometry 1024 768 2048 4096 8
-    timings 12703 144 24 29 0 120 3
-endmode
-
-mode "1024x768-80"
-    geometry 1024 768 2048 4096 8
-    timings 11910 144 24 29 0 120 3
-endmode
-
-mode "1024x768-85"
-    geometry 1024 768 2048 4096 8
-    timings 11209 144 24 29 0 120 3
-endmode
-
-mode "1280x1024-50"
-    geometry 1280 1024 2048 4096 8
-    timings 11114 232 16 39 0 160 3
-endmode
-
-mode "1280x1024-60"
-    geometry 1280 1024 2048 4096 8
-    timings 9262 232 16 39 0 160 3
-endmode
-
-mode "1280x1024-70"
-    geometry 1280 1024 2048 4096 8
-    timings 7939 232 16 39 0 160 3
-endmode
-
-mode "1280x1024-72"
-    geometry 1280 1024 2048 4096 8
-    timings 7719 232 16 39 0 160 3
-endmode
-
-mode "1280x1024-75"
-    geometry 1280 1024 2048 4096 8
-    timings 7410 232 16 39 0 160 3
-endmode
-
-mode "1280x1024-80"
-    geometry 1280 1024 2048 4096 8
-    timings 6946 232 16 39 0 160 3
-endmode
-
-mode "1280x1024-85"
-    geometry 1280 1024 2048 4096 8
-    timings 6538 232 16 39 0 160 3
-endmode

Documentation/fb/cyblafb/performance

@@ -1,79 +0,0 @@
-Speed
-=====
-
-CyBlaFB is much faster than tridentfb and vesafb. Compare the performance data
-for mode 1280x1024-[8,16,32]@61 Hz.
-
-Test 1: Cat a file with 2000 lines of 0 characters.
-Test 2: Cat a file with 2000 lines of 80 characters.
-Test 3: Cat a file with 2000 lines of 160 characters.
-
-All values show system time use in seconds, kernel 2.6.12 was used for
-the measurements. 2.6.13 is a bit slower, 2.6.14 hopefully will include a
-patch that speeds up kernel bitblitting a lot ( > 20%).
-
-+-----------+-----------------------------------------------------+
-|	    |			not accelerated 		  |
-| TRIDENTFB +-----------------+-----------------+-----------------+
-| of 2.6.12 |	   8 bpp      |     16 bpp	|     32 bpp	  |
-|	    | noypan |	 ypan | noypan |   ypan | noypan |   ypan |
-+-----------+--------+--------+--------+--------+--------+--------+
-|    Test 1 |	4.31 |	 4.33 |   6.05 |  12.81 |  ----  |  ----  |
-|    Test 2 |  67.94 |	 5.44 | 123.16 |  14.79 |  ----  |  ----  |
-|    Test 3 | 131.36 |	 6.55 | 240.12 |  16.76 |  ----  |  ----  |
-+-----------+--------+--------+--------+--------+--------+--------+
-|  Comments |		      | 		| completely bro- |
-|	    |		      | 		| ken, monitor	  |
-|	    |		      | 		| switches off	  |
-+-----------+-----------------+-----------------+-----------------+
-
-
-+-----------+-----------------------------------------------------+
-|	    |			  accelerated			  |
-| TRIDENTFB +-----------------+-----------------+-----------------+
-| of 2.6.12 |	   8 bpp      |     16 bpp	|     32 bpp	  |
-|	    | noypan |	 ypan | noypan |   ypan | noypan |   ypan |
-+-----------+--------+--------+--------+--------+--------+--------+
-|    Test 1 |  ----  |	----  |  20.62 |   1.22 |  ----  |  ----  |
-|    Test 2 |  ----  |	----  |  22.61 |   3.19 |  ----  |  ----  |
-|    Test 3 |  ----  |	----  |  24.59 |   5.16 |  ----  |  ----  |
-+-----------+--------+--------+--------+--------+--------+--------+
-|  Comments | broken, writing | broken, ok only | completely bro- |
-|	    | to wrong places | if bgcolor is	| ken, monitor	  |
-|	    | on screen + bug | black, bug in	| switches off	  |
-|	    | in fillrect()   | fillrect()	|		  |
-+-----------+-----------------+-----------------+-----------------+
-
-
-+-----------+-----------------------------------------------------+
-|	    |			not accelerated 		  |
-|   VESAFB  +-----------------+-----------------+-----------------+
-| of 2.6.12 |	   8 bpp      |     16 bpp	|     32 bpp	  |
-|	    | noypan |	 ypan | noypan |   ypan | noypan |   ypan |
-+-----------+--------+--------+--------+--------+--------+--------+
-|    Test 1 |	4.26 |	 3.76 |   5.99 |   7.23 |  ----  |  ----  |
-|    Test 2 |  65.65 |	 4.89 | 120.88 |   9.08 |  ----  |  ----  |
-|    Test 3 | 126.91 |	 5.94 | 235.77 |  11.03 |  ----  |  ----  |
-+-----------+--------+--------+--------+--------+--------+--------+
-|  Comments | vga=0x307       | vga=0x31a	| vga=0x31b not   |
-|	    | fh=80kHz	      | fh=80kHz	| supported by	  |
-|	    | fv=75kHz	      | fv=75kHz	| video BIOS and  |
-|	    |		      | 		| hardware	  |
-+-----------+-----------------+-----------------+-----------------+
-
-
-+-----------+-----------------------------------------------------+
-|	    |			  accelerated			  |
-|  CYBLAFB  +-----------------+-----------------+-----------------+
-|	    |	   8 bpp      |     16 bpp	|     32 bpp	  |
-|	    | noypan |	 ypan | noypan |   ypan | noypan |   ypan |
-+-----------+--------+--------+--------+--------+--------+--------+
-|    Test 1 |	8.02 |	 0.23 |  19.04 |   0.61 |  57.12 |   2.74 |
-|    Test 2 |	8.38 |	 0.55 |  19.39 |   0.92 |  57.54 |   3.13 |
-|    Test 3 |	8.73 |	 0.86 |  19.74 |   1.24 |  57.95 |   3.51 |
-+-----------+--------+--------+--------+--------+--------+--------+
-|  Comments |		      | 		|		  |
-|	    |		      | 		|		  |
-|	    |		      | 		|		  |
-|	    |		      | 		|		  |
-+-----------+-----------------+-----------------+-----------------+

Documentation/fb/cyblafb/todo

@@ -1,31 +0,0 @@
-TODO / Missing features
-=======================
-
-Verify LCD stuff		"stretch" and "center" options are
-				completely untested ... this code needs to be
-				verified. As I don't have access to such
-				hardware, please contact me if you are
-				willing run some tests.
-
-Interlaced video modes		The reason that interleaved
-				modes are disabled is that I do not know
-				the meaning of the vertical interlace
-				parameter. Also the datasheet mentions a
-				bit d8 of a horizontal interlace parameter,
-				but nowhere the lower 8 bits. Please help
-				if you can.
-
-low-res double scan modes	Who needs it?
-
-accelerated color blitting	Who needs it? The console driver does use color
-				blitting for nothing but drawing the penguine,
-				everything else is done using color expanding
-				blitting of 1bpp character bitmaps.
-
-ioctls				Who needs it?
-
-TV-out				Will be done later. Use "vga= " at boot time
-				to set a suitable video mode.
-
-???				Feel free to contact me if you have any
-				feature requests

Documentation/fb/cyblafb/usage

@@ -1,217 +0,0 @@
-CyBlaFB is a framebuffer driver for the Cyberblade/i1 graphics core integrated
-into the VIA Apollo PLE133 (aka vt8601) south bridge. It is developed and
-tested using a VIA EPIA 5000 board.
-
-Cyblafb - compiled into the kernel or as a module?
-==================================================
-
-You might compile cyblafb either as a module or compile it permanently into the
-kernel.
-
-Unless you have a real reason to do so you should not compile both vesafb and
-cyblafb permanently into the kernel. It's possible and it helps during the
-developement cycle, but it's useless and will at least block some otherwise
-usefull memory for ordinary users.
-
-Selecting Modes
-===============
-
-	Startup Mode
-	============
-
-	First of all, you might use the "vga=???" boot parameter as it is
-	documented in vesafb.txt and svga.txt. Cyblafb will detect the video
-	mode selected and will use the geometry and timings found by
-	inspecting the hardware registers.
-
-		video=cyblafb vga=0x317
-
-	Alternatively you might use a combination of the mode, ref and bpp
-	parameters. If you compiled the driver into the kernel, add something
-	like this to the kernel command line:
-
-		video=cyblafb:1280x1024,bpp=16,ref=50 ...
-
-	If you compiled the driver as a module, the same mode would be
-	selected by the following command:
-
-		modprobe cyblafb mode=1280x1024 bpp=16 ref=50 ...
-
-	None of the modes possible to select as startup modes are affected by
-	the problems described at the end of the next subsection.
-
-	For all startup modes cyblafb chooses a virtual x resolution of 2048,
-	the only exception is mode 1280x1024 in combination with 32 bpp. This
-	allows ywrap scrolling for all those modes if rotation is 0 or 2, and
-	also fast scrolling if rotation is 1 or 3. The default virtual y reso-
-	lution is 4096 for bpp == 8, 2048 for bpp==16 and 1024 for bpp == 32,
-	again with the only exception of 1280x1024 at 32 bpp.
-
-	Please do set your video memory size to 8 Mb in the Bios setup. Other
-	values will work, but performace is decreased for a lot of modes.
-
-	Mode changes using fbset
-	========================
-
-	You might use fbset to change the video mode, see "man fbset". Cyblafb
-	generally does assume that you know what you are doing. But it does
-	some checks, especially those that are needed to prevent you from
-	damaging your hardware.
-
-		- only 8, 16, 24 and 32 bpp video modes are accepted
-		- interlaced video modes are not accepted
-		- double scan video modes are not accepted
-		- if a flat panel is found, cyblafb does not allow you
-		  to program a resolution higher than the physical
-		  resolution of the flat panel monitor
-		- cyblafb does not allow vclk to exceed 230 MHz. As 32 bpp
-		  and (currently) 24 bit modes use a doubled vclk internally,
-		  the dotclock limit as seen by fbset is 115 MHz for those
-		  modes and 230 MHz for 8 and 16 bpp modes.
-		- cyblafb will allow you to select very high resolutions as
-		  long as the hardware can be programmed to these modes. The
-		  documented limit 1600x1200 is not enforced, but don't expect
-		  perfect signal quality.
-
-	Any request that violates the rules given above will be either changed
-	to something the hardware supports or an error value will be returned.
-
-	If you program a virtual y resolution higher than the hardware limit,
-	cyblafb will silently decrease that value to the highest possible
-	value. The same is true for a virtual x resolution that is not
-	supported by the hardware. Cyblafb tries to adapt vyres first because
-	vxres decides if ywrap scrolling is possible or not.
-
-	Attempts to disable acceleration are ignored, I believe that this is
-	safe.
-
-	Some video modes that should work do not work as expected. If you use
-	the standard fb.modes, fbset 640x480-60 will program that mode, but
-	you will see a vertical area, about two characters wide, with only
-	much darker characters than the other characters on the screen.
-	Cyblafb does allow that mode to be set, as it does not violate the
-	official specifications. It would need a lot of code to reliably sort
-	out all invalid modes, playing around with the margin values will
-	give a valid mode quickly. And if cyblafb would detect such an invalid
-	mode, should it silently alter the requested values or should it
-	report an error? Both options have some pros and cons. As stated
-	above, none of the startup modes are affected, and if you set
-	verbosity to 1 or higher, cyblafb will print the fbset command that
-	would be needed to program that mode using fbset.
-
-
-Other Parameters
-================
-
-
-crt		don't autodetect, assume monitor connected to
-		standard VGA connector
-
-fp		don't autodetect, assume flat panel display
-		connected to flat panel monitor interface
-
-nativex 	inform driver about native x resolution of
-		flat panel monitor connected to special
-		interface (should be autodetected)
-
-stretch 	stretch image to adapt low resolution modes to
-		higer resolutions of flat panel monitors
-		connected to special interface
-
-center		center image to adapt low resolution modes to
-		higer resolutions of flat panel monitors
-		connected to special interface
-
-memsize 	use if autodetected memsize is wrong ...
-		should never be necessary
-
-nopcirr 	disable PCI read retry
-nopciwr 	disable PCI write retry
-nopcirb 	disable PCI read bursts
-nopciwb 	disable PCI write bursts
-
-bpp		bpp for specified modes
-		valid values: 8 || 16 || 24 || 32
-
-ref		refresh rate for specified mode
-		valid values: 50 <= ref <= 85
-
-mode		640x480 or 800x600 or 1024x768 or 1280x1024
-		if not specified, the startup mode will be detected
-		and used, so you might also use the vga=??? parameter
-		described in vesafb.txt. If you do not specify a mode,
-		bpp and ref parameters are ignored.
-
-verbosity	0 is the default, increase to at least 2 for every
-		bug report!
-
-Development hints
-=================
-
-It's much faster do compile a module and to load the new version after
-unloading the old module than to compile a new kernel and to reboot. So if you
-try to work on cyblafb, it might be a good idea to use cyblafb as a module.
-In real life, fast often means dangerous, and that's also the case here. If
-you introduce a serious bug when cyblafb is compiled into the kernel, the
-kernel will lock or oops with a high probability before the file system is
-mounted, and the danger for your data is low. If you load a broken own version
-of cyblafb on a running system, the danger for the integrity of the file
-system is much higher as you might need a hard reset afterwards. Decide
-yourself.
-
-Module unloading, the vfb method
-================================
-
-If you want to unload/reload cyblafb using the virtual framebuffer, you need
-to enable vfb support in the kernel first. After that, load the modules as
-shown below:
-
-	modprobe vfb vfb_enable=1
-	modprobe fbcon
-	modprobe cyblafb
-	fbset -fb /dev/fb1 1280x1024-60 -vyres 2662
-	con2fb /dev/fb1 /dev/tty1
-	...
-
-If you now made some changes to cyblafb and want to reload it, you might do it
-as show below:
-
-	con2fb /dev/fb0 /dev/tty1
-	...
-	rmmod cyblafb
-	modprobe cyblafb
-	con2fb /dev/fb1 /dev/tty1
-	...
-
-Of course, you might choose another mode, and most certainly you also want to
-map some other /dev/tty* to the real framebuffer device. You might also choose
-to compile fbcon as a kernel module or place it permanently in the kernel.
-
-I do not know of any way to unload fbcon, and fbcon will prevent the
-framebuffer device loaded first from unloading. [If there is a way, then
-please add a description here!]
-
-Module unloading, the vesafb method
-===================================
-
-Configure the kernel:
-
-	<*> Support for frame buffer devices
-	[*]   VESA VGA graphics support
-	<M>   Cyberblade/i1 support
-
-Add e.g. "video=vesafb:ypan vga=0x307" to the kernel parameters. The ypan
-parameter is important, choose any vga parameter you like as long as it is
-a graphics mode.
-
-After booting, load cyblafb without any mode and bpp parameter and assign
-cyblafb to individual ttys using con2fb, e.g.:
-
-	modprobe cyblafb
-	con2fb /dev/fb1 /dev/tty1
-
-Unloading cyblafb works without problems after you assign vesafb to all
-ttys again, e.g.:
-
-	con2fb /dev/fb0 /dev/tty1
-	rmmod cyblafb

Documentation/fb/cyblafb/whatsnew

@@ -1,29 +0,0 @@
-0.62
-====
-
-      - the vesafb parameter has been removed as I decided to allow the
-      	feature without any special parameter.
-
-      - Cyblafb does not use the vga style of panning any longer, now the
-      	"right view" register in the graphics engine IO space is used. Without
-	that change it was impossible to use all available memory, and without
-	access to all available memory it is impossible to ywrap.
-
-      - The imageblit function now uses hardware acceleration for all font
-        widths. Hardware blitting across pixel column 2048 is broken in the
-	cyberblade/i1 graphics core, but we work around that hardware bug.
-
-      - modes with vxres != xres are supported now.
-
-      - ywrap scrolling is supported now and the default. This is a big
-        performance gain.
-
-      - default video modes use vyres > yres and vxres > xres to allow
-        almost optimal scrolling speed for normal and rotated screens
-
-      - some features mainly usefull for debugging the upper layers of the
-        framebuffer system have been added, have a look at the code
-
-      - fixed: Oops after unloading cyblafb when reading /proc/io*
-
-      - we work around some bugs of the higher framebuffer layers.

Documentation/fb/cyblafb/whycyblafb

@@ -1,85 +0,0 @@
-I tried the following framebuffer drivers:
-
-	- TRIDENTFB is full of bugs. Acceleration is broken for Blade3D
-	  graphics cores like the cyberblade/i1. It claims to support a great
-	  number of devices, but documentation for most of these devices is
-	  unfortunately not available. There is _no_ reason to use tridentfb
-	  for cyberblade/i1 + CRT users. VESAFB is faster, and the one
-	  advantage, mode switching, is broken in tridentfb.
-
-	- VESAFB is used by many distributions as a standard. Vesafb does
-	  not support mode switching. VESAFB is a bit faster than the working
-	  configurations of TRIDENTFB, but it is still too slow, even if you
-	  use ypan.
-
-	- EPIAFB (you'll find it on sourceforge) supports the Cyberblade/i1
-	  graphics core, but it still has serious bugs and developement seems
-	  to have stopped. This is the one driver with TV-out support. If you
-	  do need this feature, try epiafb.
-
-None of these drivers was a real option for me.
-
-I believe that is unreasonable to change code that announces to support 20
-devices if I only have more or less sufficient documentation for exactly one
-of these. The risk of breaking device foo while fixing device bar is too high.
-
-So I decided to start CyBlaFB as a stripped down tridentfb.
-
-All code specific to other Trident chips has been removed. After that there
-were a lot of cosmetic changes to increase the readability of the code. All
-register names were changed to those mnemonics used in the datasheet. Function
-and macro names were changed if they hindered easy understanding of the code.
-
-After that I debugged the code and implemented some new features. I'll try to
-give a little summary of the main changes:
-
-	- calculation of vertical and horizontal timings was fixed
-
-	- video signal quality has been improved dramatically
-
-	- acceleration:
-
-		- fillrect and copyarea were fixed and reenabled
-
-		- color expanding imageblit was newly implemented, color
-		  imageblit (only used to draw the penguine) still uses the
-		  generic code.
-
-		- init of the acceleration engine was improved and moved to a
-		  place where it really works ...
-
-		- sync function has a timeout now and tries to reset and
-		  reinit the accel engine if necessary
-
-		- fewer slow copyarea calls when doing ypan scrolling by using
-		  undocumented bit d21 of screen start address stored in
-		  CR2B[5]. BIOS does use it also, so this should be safe.
-
-	- cyblafb rejects any attempt to set modes that would cause vclk
-	  values above reasonable 230 MHz. 32bit modes use a clock
-	  multiplicator of 2, so fbset does show the correct values for
-	  pixclock but not for vclk in this case. The fbset limit is 115 MHz
-	  for 32 bpp modes.
-
-	- cyblafb rejects modes known to be broken or unimplemented (all
-	  interlaced modes, all doublescan modes for now)
-
-	- cyblafb now works independant of the video mode in effect at startup
-	  time (tridentfb does not init all needed registers to reasonable
-	  values)
-
-	- switching between video modes does work reliably now
-
-	- the first video mode now is the one selected on startup using the
-	  vga=???? mechanism or any of
-		- 640x480, 800x600, 1024x768, 1280x1024
-		- 8, 16, 24 or 32 bpp
-		- refresh between 50 Hz and 85 Hz, 1 Hz steps (1280x1024-32
-		  is limited to 63Hz)
-
-	- pci retry and pci burst mode are settable (try to disable if you
-	  experience latency problems)
-
-	- built as a module cyblafb might be unloaded and reloaded using
-	  the vfb module and con2vt or might be used together with vesafb
-

Documentation/fb/uvesafb.txt

@@ -59,7 +59,8 @@ Accepted options:
 ypan    Enable display panning using the VESA protected mode
         interface.  The visible screen is just a window of the
         video memory, console scrolling is done by changing the
-        start of the window.  Available on x86 only.
+        start of the window.  This option is available on x86
+        only and is the default option on that architecture.
 
 ywrap   Same as ypan, but assumes your gfx board can wrap-around
         the video memory (i.e. starts reading from top if it
@@ -67,7 +68,7 @@ ywrap   Same as ypan, but assumes your gfx board can wrap-around
         Available on x86 only.
 
 redraw  Scroll by redrawing the affected part of the screen, this
-        is the safe (and slow) default.
+        is the default on non-x86.
 
 (If you're using uvesafb as a module, the above three options are
  used a parameter of the scroll option, e.g. scroll=ypan.)
@@ -182,7 +183,7 @@ from the Video BIOS if you set pixclock to 0 in fb_var_screeninfo.
 
 --
  Michal Januszewski <spock@gentoo.org>
- Last updated: 2007-06-16
+ Last updated: 2009-03-30
 
  Documentation of the uvesafb options is loosely based on vesafb.txt.
 

Documentation/feature-removal-schedule.txt

@@ -64,10 +64,10 @@ Who:	Pavel Machek <pavel@suse.cz>
 
 ---------------------------
 
-What:	Video4Linux API 1 ioctls and video_decoder.h from Video devices.
-When:	December 2008
-Files:	include/linux/video_decoder.h include/linux/videodev.h
-Check:	include/linux/video_decoder.h include/linux/videodev.h
+What:	Video4Linux API 1 ioctls and from Video devices.
+When:	July 2009
+Files:	include/linux/videodev.h
+Check:	include/linux/videodev.h
 Why:	V4L1 AP1 was replaced by V4L2 API during migration from 2.4 to 2.6
 	series. The old API have lots of drawbacks and don't provide enough
 	means to work with all video and audio standards. The newer API is
@@ -255,6 +255,16 @@ Who:	Jan Engelhardt <jengelh@computergmbh.de>
 
 ---------------------------
 
+What:	GPIO autorequest on gpio_direction_{input,output}() in gpiolib
+When:	February 2010
+Why:	All callers should use explicit gpio_request()/gpio_free().
+	The autorequest mechanism in gpiolib was provided mostly as a
+	migration aid for legacy GPIO interfaces (for SOC based GPIOs).
+	Those users have now largely migrated.  Platforms implementing
+	the GPIO interfaces without using gpiolib will see no changes.
+Who:	David Brownell <dbrownell@users.sourceforge.net>
+---------------------------
+
 What:	b43 support for firmware revision < 410
 When:	The schedule was July 2008, but it was decided that we are going to keep the
         code as long as there are no major maintanance headaches.
@@ -273,13 +283,6 @@ Who:	Glauber Costa <gcosta@redhat.com>
 
 ---------------------------
 
-What:	remove HID compat support
-When:	2.6.29
-Why:	needed only as a temporary solution until distros fix themselves up
-Who:	Jiri Slaby <jirislaby@gmail.com>
-
----------------------------
-
 What: print_fn_descriptor_symbol()
 When: October 2009
 Why:  The %pF vsprintf format provides the same functionality in a
@@ -311,6 +314,18 @@ Who:	Vlad Yasevich <vladislav.yasevich@hp.com>
 
 ---------------------------
 
+What:	Ability for non root users to shm_get hugetlb pages based on mlock
+	resource limits
+When:	2.6.31
+Why:	Non root users need to be part of /proc/sys/vm/hugetlb_shm_group or
+	have CAP_IPC_LOCK to be able to allocate shm segments backed by
+	huge pages.  The mlock based rlimit check to allow shm hugetlb is
+	inconsistent with mmap based allocations.  Hence it is being
+	deprecated.
+Who:	Ravikiran Thirumalai <kiran@scalex86.org>
+
+---------------------------
+
 What:	CONFIG_THERMAL_HWMON
 When:	January 2009
 Why:	This option was introduced just to allow older lm-sensors userspace
@@ -339,7 +354,8 @@ Who:  Krzysztof Piotr Oledzki <ole@ans.pl>
 
 ---------------------------
 
-What:	i2c_attach_client(), i2c_detach_client(), i2c_driver->detach_client()
+What:	i2c_attach_client(), i2c_detach_client(), i2c_driver->detach_client(),
+	i2c_adapter->client_register(), i2c_adapter->client_unregister
 When:	2.6.30
 Check:	i2c_attach_client i2c_detach_client
 Why:	Deprecated by the new (standard) device driver binding model. Use
@@ -380,3 +396,44 @@ Why:	The defines and typedefs (hw_interrupt_type, no_irq_type, irq_desc_t)
 	have been kept around for migration reasons. After more than two years
 	it's time to remove them finally
 Who:	Thomas Gleixner <tglx@linutronix.de>
+
+---------------------------
+
+What:	fakephp and associated sysfs files in /sys/bus/pci/slots/
+When:	2011
+Why:	In 2.6.27, the semantics of /sys/bus/pci/slots was redefined to
+	represent a machine's physical PCI slots. The change in semantics
+	had userspace implications, as the hotplug core no longer allowed
+	drivers to create multiple sysfs files per physical slot (required
+	for multi-function devices, e.g.). fakephp was seen as a developer's
+	tool only, and its interface changed. Too late, we learned that
+	there were some users of the fakephp interface.
+
+	In 2.6.30, the original fakephp interface was restored. At the same
+	time, the PCI core gained the ability that fakephp provided, namely
+	function-level hot-remove and hot-add.
+
+	Since the PCI core now provides the same functionality, exposed in:
+
+		/sys/bus/pci/rescan
+		/sys/bus/pci/devices/.../remove
+		/sys/bus/pci/devices/.../rescan
+
+	there is no functional reason to maintain fakephp as well.
+
+	We will keep the existing module so that 'modprobe fakephp' will
+	present the old /sys/bus/pci/slots/... interface for compatibility,
+	but users are urged to migrate their applications to the API above.
+
+	After a reasonable transition period, we will remove the legacy
+	fakephp interface.
+Who:	Alex Chiang <achiang@hp.com>
+
+---------------------------
+
+What:	i2c-voodoo3 driver
+When:	October 2009
+Why:	Superseded by tdfxfb. I2C/DDC support used to live in a separate
+	driver but this caused driver conflicts.
+Who:	Jean Delvare <khali@linux-fr.org>
+	Krzysztof Helt <krzysztof.h1@wp.pl>

Documentation/filesystems/00-INDEX

@@ -68,6 +68,8 @@ ncpfs.txt
 	- info on Novell Netware(tm) filesystem using NCP protocol.
 nfsroot.txt
 	- short guide on setting up a diskless box with NFS root filesystem.
+nilfs2.txt
+	- info and mount options for the NILFS2 filesystem.
 ntfs.txt
 	- info and mount options for the NTFS filesystem (Windows NT).
 ocfs2.txt

Documentation/filesystems/Locking

@@ -505,23 +505,31 @@ prototypes:
 	void (*open)(struct vm_area_struct*);
 	void (*close)(struct vm_area_struct*);
 	int (*fault)(struct vm_area_struct*, struct vm_fault *);
-	int (*page_mkwrite)(struct vm_area_struct *, struct page *);
+	int (*page_mkwrite)(struct vm_area_struct *, struct vm_fault *);
 	int (*access)(struct vm_area_struct *, unsigned long, void*, int, int);
 
 locking rules:
 		BKL	mmap_sem	PageLocked(page)
 open:		no	yes
 close:		no	yes
-fault:		no	yes
-page_mkwrite:	no	yes		no
+fault:		no	yes		can return with page locked
+page_mkwrite:	no	yes		can return with page locked
 access:		no	yes
 
-	->page_mkwrite() is called when a previously read-only page is
-about to become writeable. The file system is responsible for
-protecting against truncate races. Once appropriate action has been
-taking to lock out truncate, the page range should be verified to be
-within i_size. The page mapping should also be checked that it is not
-NULL.
+	->fault() is called when a previously not present pte is about
+to be faulted in. The filesystem must find and return the page associated
+with the passed in "pgoff" in the vm_fault structure. If it is possible that
+the page may be truncated and/or invalidated, then the filesystem must lock
+the page, then ensure it is not already truncated (the page lock will block
+subsequent truncate), and then return with VM_FAULT_LOCKED, and the page
+locked. The VM will unlock the page.
+
+	->page_mkwrite() is called when a previously read-only pte is
+about to become writeable. The filesystem again must ensure that there are
+no truncate/invalidate races, and then return with the page locked. If
+the page has been truncated, the filesystem should not look up a new page
+like the ->fault() handler, but simply return with VM_FAULT_NOPAGE, which
+will cause the VM to retry the fault.
 
 	->access() is called when get_user_pages() fails in
 acces_process_vm(), typically used to debug a process through

Documentation/filesystems/caching/backend-api.txt

@@ -0,0 +1,658 @@
+			  ==========================
+			  FS-CACHE CACHE BACKEND API
+			  ==========================
+
+The FS-Cache system provides an API by which actual caches can be supplied to
+FS-Cache for it to then serve out to network filesystems and other interested
+parties.
+
+This API is declared in <linux/fscache-cache.h>.
+
+
+====================================
+INITIALISING AND REGISTERING A CACHE
+====================================
+
+To start off, a cache definition must be initialised and registered for each
+cache the backend wants to make available.  For instance, CacheFS does this in
+the fill_super() operation on mounting.
+
+The cache definition (struct fscache_cache) should be initialised by calling:
+
+	void fscache_init_cache(struct fscache_cache *cache,
+				struct fscache_cache_ops *ops,
+				const char *idfmt,
+				...);
+
+Where:
+
+ (*) "cache" is a pointer to the cache definition;
+
+ (*) "ops" is a pointer to the table of operations that the backend supports on
+     this cache; and
+
+ (*) "idfmt" is a format and printf-style arguments for constructing a label
+     for the cache.
+
+
+The cache should then be registered with FS-Cache by passing a pointer to the
+previously initialised cache definition to:
+
+	int fscache_add_cache(struct fscache_cache *cache,
+			      struct fscache_object *fsdef,
+			      const char *tagname);
+
+Two extra arguments should also be supplied:
+
+ (*) "fsdef" which should point to the object representation for the FS-Cache
+     master index in this cache.  Netfs primary index entries will be created
+     here.  FS-Cache keeps the caller's reference to the index object if
+     successful and will release it upon withdrawal of the cache.
+
+ (*) "tagname" which, if given, should be a text string naming this cache.  If
+     this is NULL, the identifier will be used instead.  For CacheFS, the
+     identifier is set to name the underlying block device and the tag can be
+     supplied by mount.
+
+This function may return -ENOMEM if it ran out of memory or -EEXIST if the tag
+is already in use.  0 will be returned on success.
+
+
+=====================
+UNREGISTERING A CACHE
+=====================
+
+A cache can be withdrawn from the system by calling this function with a
+pointer to the cache definition:
+
+	void fscache_withdraw_cache(struct fscache_cache *cache);
+
+In CacheFS's case, this is called by put_super().
+
+
+========
+SECURITY
+========
+
+The cache methods are executed one of two contexts:
+
+ (1) that of the userspace process that issued the netfs operation that caused
+     the cache method to be invoked, or
+
+ (2) that of one of the processes in the FS-Cache thread pool.
+
+In either case, this may not be an appropriate context in which to access the
+cache.
+
+The calling process's fsuid, fsgid and SELinux security identities may need to
+be masqueraded for the duration of the cache driver's access to the cache.
+This is left to the cache to handle; FS-Cache makes no effort in this regard.
+
+
+===================================
+CONTROL AND STATISTICS PRESENTATION
+===================================
+
+The cache may present data to the outside world through FS-Cache's interfaces
+in sysfs and procfs - the former for control and the latter for statistics.
+
+A sysfs directory called /sys/fs/fscache/<cachetag>/ is created if CONFIG_SYSFS
+is enabled.  This is accessible through the kobject struct fscache_cache::kobj
+and is for use by the cache as it sees fit.
+
+
+========================
+RELEVANT DATA STRUCTURES
+========================
+
+ (*) Index/Data file FS-Cache representation cookie:
+
+	struct fscache_cookie {
+		struct fscache_object_def	*def;
+		struct fscache_netfs		*netfs;
+		void				*netfs_data;
+		...
+	};
+
+     The fields that might be of use to the backend describe the object
+     definition, the netfs definition and the netfs's data for this cookie.
+     The object definition contain functions supplied by the netfs for loading
+     and matching index entries; these are required to provide some of the
+     cache operations.
+
+
+ (*) In-cache object representation:
+
+	struct fscache_object {
+		int				debug_id;
+		enum {
+			FSCACHE_OBJECT_RECYCLING,
+			...
+		}				state;
+		spinlock_t			lock
+		struct fscache_cache		*cache;
+		struct fscache_cookie		*cookie;
+		...
+	};
+
+     Structures of this type should be allocated by the cache backend and
+     passed to FS-Cache when requested by the appropriate cache operation.  In
+     the case of CacheFS, they're embedded in CacheFS's internal object
+     structures.
+
+     The debug_id is a simple integer that can be used in debugging messages
+     that refer to a particular object.  In such a case it should be printed
+     using "OBJ%x" to be consistent with FS-Cache.
+
+     Each object contains a pointer to the cookie that represents the object it
+     is backing.  An object should retired when put_object() is called if it is
+     in state FSCACHE_OBJECT_RECYCLING.  The fscache_object struct should be
+     initialised by calling fscache_object_init(object).
+
+
+ (*) FS-Cache operation record:
+
+	struct fscache_operation {
+		atomic_t		usage;
+		struct fscache_object	*object;
+		unsigned long		flags;
+	#define FSCACHE_OP_EXCLUSIVE
+		void (*processor)(struct fscache_operation *op);
+		void (*release)(struct fscache_operation *op);
+		...
+	};
+
+     FS-Cache has a pool of threads that it uses to give CPU time to the
+     various asynchronous operations that need to be done as part of driving
+     the cache.  These are represented by the above structure.  The processor
+     method is called to give the op CPU time, and the release method to get
+     rid of it when its usage count reaches 0.
+
+     An operation can be made exclusive upon an object by setting the
+     appropriate flag before enqueuing it with fscache_enqueue_operation().  If
+     an operation needs more processing time, it should be enqueued again.
+
+
+ (*) FS-Cache retrieval operation record:
+
+	struct fscache_retrieval {
+		struct fscache_operation op;
+		struct address_space	*mapping;
+		struct list_head	*to_do;
+		...
+	};
+
+     A structure of this type is allocated by FS-Cache to record retrieval and
+     allocation requests made by the netfs.  This struct is then passed to the
+     backend to do the operation.  The backend may get extra refs to it by
+     calling fscache_get_retrieval() and refs may be discarded by calling
+     fscache_put_retrieval().
+
+     A retrieval operation can be used by the backend to do retrieval work.  To
+     do this, the retrieval->op.processor method pointer should be set
+     appropriately by the backend and fscache_enqueue_retrieval() called to
+     submit it to the thread pool.  CacheFiles, for example, uses this to queue
+     page examination when it detects PG_lock being cleared.
+
+     The to_do field is an empty list available for the cache backend to use as
+     it sees fit.
+
+
+ (*) FS-Cache storage operation record:
+
+	struct fscache_storage {
+		struct fscache_operation op;
+		pgoff_t			store_limit;
+		...
+	};
+
+     A structure of this type is allocated by FS-Cache to record outstanding
+     writes to be made.  FS-Cache itself enqueues this operation and invokes
+     the write_page() method on the object at appropriate times to effect
+     storage.
+
+
+================
+CACHE OPERATIONS
+================
+
+The cache backend provides FS-Cache with a table of operations that can be
+performed on the denizens of the cache.  These are held in a structure of type:
+
+	struct fscache_cache_ops
+
+ (*) Name of cache provider [mandatory]:
+
+	const char *name
+
+     This isn't strictly an operation, but should be pointed at a string naming
+     the backend.
+
+
+ (*) Allocate a new object [mandatory]:
+
+	struct fscache_object *(*alloc_object)(struct fscache_cache *cache,
+					       struct fscache_cookie *cookie)
+
+     This method is used to allocate a cache object representation to back a
+     cookie in a particular cache.  fscache_object_init() should be called on
+     the object to initialise it prior to returning.
+
+     This function may also be used to parse the index key to be used for
+     multiple lookup calls to turn it into a more convenient form.  FS-Cache
+     will call the lookup_complete() method to allow the cache to release the
+     form once lookup is complete or aborted.
+
+
+ (*) Look up and create object [mandatory]:
+
+	void (*lookup_object)(struct fscache_object *object)
+
+     This method is used to look up an object, given that the object is already
+     allocated and attached to the cookie.  This should instantiate that object
+     in the cache if it can.
+
+     The method should call fscache_object_lookup_negative() as soon as
+     possible if it determines the object doesn't exist in the cache.  If the
+     object is found to exist and the netfs indicates that it is valid then
+     fscache_obtained_object() should be called once the object is in a
+     position to have data stored in it.  Similarly, fscache_obtained_object()
+     should also be called once a non-present object has been created.
+
+     If a lookup error occurs, fscache_object_lookup_error() should be called
+     to abort the lookup of that object.
+
+
+ (*) Release lookup data [mandatory]:
+
+	void (*lookup_complete)(struct fscache_object *object)
+
+     This method is called to ask the cache to release any resources it was
+     using to perform a lookup.
+
+
+ (*) Increment object refcount [mandatory]:
+
+	struct fscache_object *(*grab_object)(struct fscache_object *object)
+
+     This method is called to increment the reference count on an object.  It
+     may fail (for instance if the cache is being withdrawn) by returning NULL.
+     It should return the object pointer if successful.
+
+
+ (*) Lock/Unlock object [mandatory]:
+
+	void (*lock_object)(struct fscache_object *object)
+	void (*unlock_object)(struct fscache_object *object)
+
+     These methods are used to exclusively lock an object.  It must be possible
+     to schedule with the lock held, so a spinlock isn't sufficient.
+
+
+ (*) Pin/Unpin object [optional]:
+
+	int (*pin_object)(struct fscache_object *object)
+	void (*unpin_object)(struct fscache_object *object)
+
+     These methods are used to pin an object into the cache.  Once pinned an
+     object cannot be reclaimed to make space.  Return -ENOSPC if there's not
+     enough space in the cache to permit this.
+
+
+ (*) Update object [mandatory]:
+
+	int (*update_object)(struct fscache_object *object)
+
+     This is called to update the index entry for the specified object.  The
+     new information should be in object->cookie->netfs_data.  This can be
+     obtained by calling object->cookie->def->get_aux()/get_attr().
+
+
+ (*) Discard object [mandatory]:
+
+	void (*drop_object)(struct fscache_object *object)
+
+     This method is called to indicate that an object has been unbound from its
+     cookie, and that the cache should release the object's resources and
+     retire it if it's in state FSCACHE_OBJECT_RECYCLING.
+
+     This method should not attempt to release any references held by the
+     caller.  The caller will invoke the put_object() method as appropriate.
+
+
+ (*) Release object reference [mandatory]:
+
+	void (*put_object)(struct fscache_object *object)
+
+     This method is used to discard a reference to an object.  The object may
+     be freed when all the references to it are released.
+
+
+ (*) Synchronise a cache [mandatory]:
+
+	void (*sync)(struct fscache_cache *cache)
+
+     This is called to ask the backend to synchronise a cache with its backing
+     device.
+
+
+ (*) Dissociate a cache [mandatory]:
+
+	void (*dissociate_pages)(struct fscache_cache *cache)
+
+     This is called to ask a cache to perform any page dissociations as part of
+     cache withdrawal.
+
+
+ (*) Notification that the attributes on a netfs file changed [mandatory]:
+
+	int (*attr_changed)(struct fscache_object *object);
+
+     This is called to indicate to the cache that certain attributes on a netfs
+     file have changed (for example the maximum size a file may reach).  The
+     cache can read these from the netfs by calling the cookie's get_attr()
+     method.
+
+     The cache may use the file size information to reserve space on the cache.
+     It should also call fscache_set_store_limit() to indicate to FS-Cache the
+     highest byte it's willing to store for an object.
+
+     This method may return -ve if an error occurred or the cache object cannot
+     be expanded.  In such a case, the object will be withdrawn from service.
+
+     This operation is run asynchronously from FS-Cache's thread pool, and
+     storage and retrieval operations from the netfs are excluded during the
+     execution of this operation.
+
+
+ (*) Reserve cache space for an object's data [optional]:
+
+	int (*reserve_space)(struct fscache_object *object, loff_t size);
+
+     This is called to request that cache space be reserved to hold the data
+     for an object and the metadata used to track it.  Zero size should be
+     taken as request to cancel a reservation.
+
+     This should return 0 if successful, -ENOSPC if there isn't enough space
+     available, or -ENOMEM or -EIO on other errors.
+
+     The reservation may exceed the current size of the object, thus permitting
+     future expansion.  If the amount of space consumed by an object would
+     exceed the reservation, it's permitted to refuse requests to allocate
+     pages, but not required.  An object may be pruned down to its reservation
+     size if larger than that already.
+
+
+ (*) Request page be read from cache [mandatory]:
+
+	int (*read_or_alloc_page)(struct fscache_retrieval *op,
+				  struct page *page,
+				  gfp_t gfp)
+
+     This is called to attempt to read a netfs page from the cache, or to
+     reserve a backing block if not.  FS-Cache will have done as much checking
+     as it can before calling, but most of the work belongs to the backend.
+
+     If there's no page in the cache, then -ENODATA should be returned if the
+     backend managed to reserve a backing block; -ENOBUFS or -ENOMEM if it
+     didn't.
+
+     If there is suitable data in the cache, then a read operation should be
+     queued and 0 returned.  When the read finishes, fscache_end_io() should be
+     called.
+
+     The fscache_mark_pages_cached() should be called for the page if any cache
+     metadata is retained.  This will indicate to the netfs that the page needs
+     explicit uncaching.  This operation takes a pagevec, thus allowing several
+     pages to be marked at once.
+
+     The retrieval record pointed to by op should be retained for each page
+     queued and released when I/O on the page has been formally ended.
+     fscache_get/put_retrieval() are available for this purpose.
+
+     The retrieval record may be used to get CPU time via the FS-Cache thread
+     pool.  If this is desired, the op->op.processor should be set to point to
+     the appropriate processing routine, and fscache_enqueue_retrieval() should
+     be called at an appropriate point to request CPU time.  For instance, the
+     retrieval routine could be enqueued upon the completion of a disk read.
+     The to_do field in the retrieval record is provided to aid in this.
+
+     If an I/O error occurs, fscache_io_error() should be called and -ENOBUFS
+     returned if possible or fscache_end_io() called with a suitable error
+     code..
+
+
+ (*) Request pages be read from cache [mandatory]:
+
+	int (*read_or_alloc_pages)(struct fscache_retrieval *op,
+				   struct list_head *pages,
+				   unsigned *nr_pages,
+				   gfp_t gfp)
+
+     This is like the read_or_alloc_page() method, except it is handed a list
+     of pages instead of one page.  Any pages on which a read operation is
+     started must be added to the page cache for the specified mapping and also
+     to the LRU.  Such pages must also be removed from the pages list and
+     *nr_pages decremented per page.
+
+     If there was an error such as -ENOMEM, then that should be returned; else
+     if one or more pages couldn't be read or allocated, then -ENOBUFS should
+     be returned; else if one or more pages couldn't be read, then -ENODATA
+     should be returned.  If all the pages are dispatched then 0 should be
+     returned.
+
+
+ (*) Request page be allocated in the cache [mandatory]:
+
+	int (*allocate_page)(struct fscache_retrieval *op,
+			     struct page *page,
+			     gfp_t gfp)
+
+     This is like the read_or_alloc_page() method, except that it shouldn't
+     read from the cache, even if there's data there that could be retrieved.
+     It should, however, set up any internal metadata required such that
+     the write_page() method can write to the cache.
+
+     If there's no backing block available, then -ENOBUFS should be returned
+     (or -ENOMEM if there were other problems).  If a block is successfully
+     allocated, then the netfs page should be marked and 0 returned.
+
+
+ (*) Request pages be allocated in the cache [mandatory]:
+
+	int (*allocate_pages)(struct fscache_retrieval *op,
+			      struct list_head *pages,
+			      unsigned *nr_pages,
+			      gfp_t gfp)
+
+     This is an multiple page version of the allocate_page() method.  pages and
+     nr_pages should be treated as for the read_or_alloc_pages() method.
+
+
+ (*) Request page be written to cache [mandatory]:
+
+	int (*write_page)(struct fscache_storage *op,
+			  struct page *page);
+
+     This is called to write from a page on which there was a previously
+     successful read_or_alloc_page() call or similar.  FS-Cache filters out
+     pages that don't have mappings.
+
+     This method is called asynchronously from the FS-Cache thread pool.  It is
+     not required to actually store anything, provided -ENODATA is then
+     returned to the next read of this page.
+
+     If an error occurred, then a negative error code should be returned,
+     otherwise zero should be returned.  FS-Cache will take appropriate action
+     in response to an error, such as withdrawing this object.
+
+     If this method returns success then FS-Cache will inform the netfs
+     appropriately.
+
+
+ (*) Discard retained per-page metadata [mandatory]:
+
+	void (*uncache_page)(struct fscache_object *object, struct page *page)
+
+     This is called when a netfs page is being evicted from the pagecache.  The
+     cache backend should tear down any internal representation or tracking it
+     maintains for this page.
+
+
+==================
+FS-CACHE UTILITIES
+==================
+
+FS-Cache provides some utilities that a cache backend may make use of:
+
+ (*) Note occurrence of an I/O error in a cache:
+
+	void fscache_io_error(struct fscache_cache *cache)
+
+     This tells FS-Cache that an I/O error occurred in the cache.  After this
+     has been called, only resource dissociation operations (object and page
+     release) will be passed from the netfs to the cache backend for the
+     specified cache.
+
+     This does not actually withdraw the cache.  That must be done separately.
+
+
+ (*) Invoke the retrieval I/O completion function:
+
+	void fscache_end_io(struct fscache_retrieval *op, struct page *page,
+			    int error);
+
+     This is called to note the end of an attempt to retrieve a page.  The
+     error value should be 0 if successful and an error otherwise.
+
+
+ (*) Set highest store limit:
+
+	void fscache_set_store_limit(struct fscache_object *object,
+				     loff_t i_size);
+
+     This sets the limit FS-Cache imposes on the highest byte it's willing to
+     try and store for a netfs.  Any page over this limit is automatically
+     rejected by fscache_read_alloc_page() and co with -ENOBUFS.
+
+
+ (*) Mark pages as being cached:
+
+	void fscache_mark_pages_cached(struct fscache_retrieval *op,
+				       struct pagevec *pagevec);
+
+     This marks a set of pages as being cached.  After this has been called,
+     the netfs must call fscache_uncache_page() to unmark the pages.
+
+
+ (*) Perform coherency check on an object:
+
+	enum fscache_checkaux fscache_check_aux(struct fscache_object *object,
+						const void *data,
+						uint16_t datalen);
+
+     This asks the netfs to perform a coherency check on an object that has
+     just been looked up.  The cookie attached to the object will determine the
+     netfs to use.  data and datalen should specify where the auxiliary data
+     retrieved from the cache can be found.
+
+     One of three values will be returned:
+
+	(*) FSCACHE_CHECKAUX_OKAY
+
+	    The coherency data indicates the object is valid as is.
+
+	(*) FSCACHE_CHECKAUX_NEEDS_UPDATE
+
+	    The coherency data needs updating, but otherwise the object is
+	    valid.
+
+	(*) FSCACHE_CHECKAUX_OBSOLETE
+
+	    The coherency data indicates that the object is obsolete and should
+	    be discarded.
+
+
+ (*) Initialise a freshly allocated object:
+
+	void fscache_object_init(struct fscache_object *object);
+
+     This initialises all the fields in an object representation.
+
+
+ (*) Indicate the destruction of an object:
+
+	void fscache_object_destroyed(struct fscache_cache *cache);
+
+     This must be called to inform FS-Cache that an object that belonged to a
+     cache has been destroyed and deallocated.  This will allow continuation
+     of the cache withdrawal process when it is stopped pending destruction of
+     all the objects.
+
+
+ (*) Indicate negative lookup on an object:
+
+	void fscache_object_lookup_negative(struct fscache_object *object);
+
+     This is called to indicate to FS-Cache that a lookup process for an object
+     found a negative result.
+
+     This changes the state of an object to permit reads pending on lookup
+     completion to go off and start fetching data from the netfs server as it's
+     known at this point that there can't be any data in the cache.
+
+     This may be called multiple times on an object.  Only the first call is
+     significant - all subsequent calls are ignored.
+
+
+ (*) Indicate an object has been obtained:
+
+	void fscache_obtained_object(struct fscache_object *object);
+
+     This is called to indicate to FS-Cache that a lookup process for an object
+     produced a positive result, or that an object was created.  This should
+     only be called once for any particular object.
+
+     This changes the state of an object to indicate:
+
+	(1) if no call to fscache_object_lookup_negative() has been made on
+	    this object, that there may be data available, and that reads can
+	    now go and look for it; and
+
+        (2) that writes may now proceed against this object.
+
+
+ (*) Indicate that object lookup failed:
+
+	void fscache_object_lookup_error(struct fscache_object *object);
+
+     This marks an object as having encountered a fatal error (usually EIO)
+     and causes it to move into a state whereby it will be withdrawn as soon
+     as possible.
+
+
+ (*) Get and release references on a retrieval record:
+
+	void fscache_get_retrieval(struct fscache_retrieval *op);
+	void fscache_put_retrieval(struct fscache_retrieval *op);
+
+     These two functions are used to retain a retrieval record whilst doing
+     asynchronous data retrieval and block allocation.
+
+
+ (*) Enqueue a retrieval record for processing.
+
+	void fscache_enqueue_retrieval(struct fscache_retrieval *op);
+
+     This enqueues a retrieval record for processing by the FS-Cache thread
+     pool.  One of the threads in the pool will invoke the retrieval record's
+     op->op.processor callback function.  This function may be called from
+     within the callback function.
+
+
+ (*) List of object state names:
+
+	const char *fscache_object_states[];
+
+     For debugging purposes, this may be used to turn the state that an object
+     is in into a text string for display purposes.

Documentation/filesystems/caching/cachefiles.txt

@@ -0,0 +1,501 @@
+	       ===============================================
+	       CacheFiles: CACHE ON ALREADY MOUNTED FILESYSTEM
+	       ===============================================
+
+Contents:
+
+ (*) Overview.
+
+ (*) Requirements.
+
+ (*) Configuration.
+
+ (*) Starting the cache.
+
+ (*) Things to avoid.
+
+ (*) Cache culling.
+
+ (*) Cache structure.
+
+ (*) Security model and SELinux.
+
+ (*) A note on security.
+
+ (*) Statistical information.
+
+ (*) Debugging.
+
+
+========
+OVERVIEW
+========
+
+CacheFiles is a caching backend that's meant to use as a cache a directory on
+an already mounted filesystem of a local type (such as Ext3).
+
+CacheFiles uses a userspace daemon to do some of the cache management - such as
+reaping stale nodes and culling.  This is called cachefilesd and lives in
+/sbin.
+
+The filesystem and data integrity of the cache are only as good as those of the
+filesystem providing the backing services.  Note that CacheFiles does not
+attempt to journal anything since the journalling interfaces of the various
+filesystems are very specific in nature.
+
+CacheFiles creates a misc character device - "/dev/cachefiles" - that is used
+to communication with the daemon.  Only one thing may have this open at once,
+and whilst it is open, a cache is at least partially in existence.  The daemon
+opens this and sends commands down it to control the cache.
+
+CacheFiles is currently limited to a single cache.
+
+CacheFiles attempts to maintain at least a certain percentage of free space on
+the filesystem, shrinking the cache by culling the objects it contains to make
+space if necessary - see the "Cache Culling" section.  This means it can be
+placed on the same medium as a live set of data, and will expand to make use of
+spare space and automatically contract when the set of data requires more
+space.
+
+
+============
+REQUIREMENTS
+============
+
+The use of CacheFiles and its daemon requires the following features to be
+available in the system and in the cache filesystem:
+
+	- dnotify.
+
+	- extended attributes (xattrs).
+
+	- openat() and friends.
+
+	- bmap() support on files in the filesystem (FIBMAP ioctl).
+
+	- The use of bmap() to detect a partial page at the end of the file.
+
+It is strongly recommended that the "dir_index" option is enabled on Ext3
+filesystems being used as a cache.
+
+
+=============
+CONFIGURATION
+=============
+
+The cache is configured by a script in /etc/cachefilesd.conf.  These commands
+set up cache ready for use.  The following script commands are available:
+
+ (*) brun <N>%
+ (*) bcull <N>%
+ (*) bstop <N>%
+ (*) frun <N>%
+ (*) fcull <N>%
+ (*) fstop <N>%
+
+	Configure the culling limits.  Optional.  See the section on culling
+	The defaults are 7% (run), 5% (cull) and 1% (stop) respectively.
+
+	The commands beginning with a 'b' are file space (block) limits, those
+	beginning with an 'f' are file count limits.
+
+ (*) dir <path>
+
+	Specify the directory containing the root of the cache.  Mandatory.
+
+ (*) tag <name>
+
+	Specify a tag to FS-Cache to use in distinguishing multiple caches.
+	Optional.  The default is "CacheFiles".
+
+ (*) debug <mask>
+
+	Specify a numeric bitmask to control debugging in the kernel module.
+	Optional.  The default is zero (all off).  The following values can be
+	OR'd into the mask to collect various information:
+
+		1	Turn on trace of function entry (_enter() macros)
+		2	Turn on trace of function exit (_leave() macros)
+		4	Turn on trace of internal debug points (_debug())
+
+	This mask can also be set through sysfs, eg:
+
+		echo 5 >/sys/modules/cachefiles/parameters/debug
+
+
+==================
+STARTING THE CACHE
+==================
+
+The cache is started by running the daemon.  The daemon opens the cache device,
+configures the cache and tells it to begin caching.  At that point the cache
+binds to fscache and the cache becomes live.
+
+The daemon is run as follows:
+
+	/sbin/cachefilesd [-d]* [-s] [-n] [-f <configfile>]
+
+The flags are:
+
+ (*) -d
+
+	Increase the debugging level.  This can be specified multiple times and
+	is cumulative with itself.
+
+ (*) -s
+
+	Send messages to stderr instead of syslog.
+
+ (*) -n
+
+	Don't daemonise and go into background.
+
+ (*) -f <configfile>
+
+	Use an alternative configuration file rather than the default one.
+
+
+===============
+THINGS TO AVOID
+===============
+
+Do not mount other things within the cache as this will cause problems.  The
+kernel module contains its own very cut-down path walking facility that ignores
+mountpoints, but the daemon can't avoid them.
+
+Do not create, rename or unlink files and directories in the cache whilst the
+cache is active, as this may cause the state to become uncertain.
+
+Renaming files in the cache might make objects appear to be other objects (the
+filename is part of the lookup key).
+
+Do not change or remove the extended attributes attached to cache files by the
+cache as this will cause the cache state management to get confused.
+
+Do not create files or directories in the cache, lest the cache get confused or
+serve incorrect data.
+
+Do not chmod files in the cache.  The module creates things with minimal
+permissions to prevent random users being able to access them directly.
+
+
+=============
+CACHE CULLING
+=============
+
+The cache may need culling occasionally to make space.  This involves
+discarding objects from the cache that have been used less recently than
+anything else.  Culling is based on the access time of data objects.  Empty
+directories are culled if not in use.
+
+Cache culling is done on the basis of the percentage of blocks and the
+percentage of files available in the underlying filesystem.  There are six
+"limits":
+
+ (*) brun
+ (*) frun
+
+     If the amount of free space and the number of available files in the cache
+     rises above both these limits, then culling is turned off.
+
+ (*) bcull
+ (*) fcull
+
+     If the amount of available space or the number of available files in the
+     cache falls below either of these limits, then culling is started.
+
+ (*) bstop
+ (*) fstop
+
+     If the amount of available space or the number of available files in the
+     cache falls below either of these limits, then no further allocation of
+     disk space or files is permitted until culling has raised things above
+     these limits again.
+
+These must be configured thusly:
+
+	0 <= bstop < bcull < brun < 100
+	0 <= fstop < fcull < frun < 100
+
+Note that these are percentages of available space and available files, and do
+_not_ appear as 100 minus the percentage displayed by the "df" program.
+
+The userspace daemon scans the cache to build up a table of cullable objects.
+These are then culled in least recently used order.  A new scan of the cache is
+started as soon as space is made in the table.  Objects will be skipped if
+their atimes have changed or if the kernel module says it is still using them.
+
+
+===============
+CACHE STRUCTURE
+===============
+
+The CacheFiles module will create two directories in the directory it was
+given:
+
+ (*) cache/
+
+ (*) graveyard/
+
+The active cache objects all reside in the first directory.  The CacheFiles
+kernel module moves any retired or culled objects that it can't simply unlink
+to the graveyard from which the daemon will actually delete them.
+
+The daemon uses dnotify to monitor the graveyard directory, and will delete
+anything that appears therein.
+
+
+The module represents index objects as directories with the filename "I..." or
+"J...".  Note that the "cache/" directory is itself a special index.
+
+Data objects are represented as files if they have no children, or directories
+if they do.  Their filenames all begin "D..." or "E...".  If represented as a
+directory, data objects will have a file in the directory called "data" that
+actually holds the data.
+
+Special objects are similar to data objects, except their filenames begin
+"S..." or "T...".
+
+
+If an object has children, then it will be represented as a directory.
+Immediately in the representative directory are a collection of directories
+named for hash values of the child object keys with an '@' prepended.  Into
+this directory, if possible, will be placed the representations of the child
+objects:
+
+	INDEX     INDEX      INDEX                             DATA FILES
+	========= ========== ================================= ================
+	cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400
+	cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...DB1ry
+	cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...N22ry
+	cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...FP1ry
+
+
+If the key is so long that it exceeds NAME_MAX with the decorations added on to
+it, then it will be cut into pieces, the first few of which will be used to
+make a nest of directories, and the last one of which will be the objects
+inside the last directory.  The names of the intermediate directories will have
+'+' prepended:
+
+	J1223/@23/+xy...z/+kl...m/Epqr
+
+
+Note that keys are raw data, and not only may they exceed NAME_MAX in size,
+they may also contain things like '/' and NUL characters, and so they may not
+be suitable for turning directly into a filename.
+
+To handle this, CacheFiles will use a suitably printable filename directly and
+"base-64" encode ones that aren't directly suitable.  The two versions of
+object filenames indicate the encoding:
+
+	OBJECT TYPE	PRINTABLE	ENCODED
+	===============	===============	===============
+	Index		"I..."		"J..."
+	Data		"D..."		"E..."
+	Special		"S..."		"T..."
+
+Intermediate directories are always "@" or "+" as appropriate.
+
+
+Each object in the cache has an extended attribute label that holds the object
+type ID (required to distinguish special objects) and the auxiliary data from
+the netfs.  The latter is used to detect stale objects in the cache and update
+or retire them.
+
+
+Note that CacheFiles will erase from the cache any file it doesn't recognise or
+any file of an incorrect type (such as a FIFO file or a device file).
+
+
+==========================
+SECURITY MODEL AND SELINUX
+==========================
+
+CacheFiles is implemented to deal properly with the LSM security features of
+the Linux kernel and the SELinux facility.
+
+One of the problems that CacheFiles faces is that it is generally acting on
+behalf of a process, and running in that process's context, and that includes a
+security context that is not appropriate for accessing the cache - either
+because the files in the cache are inaccessible to that process, or because if
+the process creates a file in the cache, that file may be inaccessible to other
+processes.
+
+The way CacheFiles works is to temporarily change the security context (fsuid,
+fsgid and actor security label) that the process acts as - without changing the
+security context of the process when it the target of an operation performed by
+some other process (so signalling and suchlike still work correctly).
+
+
+When the CacheFiles module is asked to bind to its cache, it:
+
+ (1) Finds the security label attached to the root cache directory and uses
+     that as the security label with which it will create files.  By default,
+     this is:
+
+	cachefiles_var_t
+
+ (2) Finds the security label of the process which issued the bind request
+     (presumed to be the cachefilesd daemon), which by default will be:
+
+	cachefilesd_t
+
+     and asks LSM to supply a security ID as which it should act given the
+     daemon's label.  By default, this will be:
+
+	cachefiles_kernel_t
+
+     SELinux transitions the daemon's security ID to the module's security ID
+     based on a rule of this form in the policy.
+
+	type_transition <daemon's-ID> kernel_t : process <module's-ID>;
+
+     For instance:
+
+	type_transition cachefilesd_t kernel_t : process cachefiles_kernel_t;
+
+
+The module's security ID gives it permission to create, move and remove files
+and directories in the cache, to find and access directories and files in the
+cache, to set and access extended attributes on cache objects, and to read and
+write files in the cache.
+
+The daemon's security ID gives it only a very restricted set of permissions: it
+may scan directories, stat files and erase files and directories.  It may
+not read or write files in the cache, and so it is precluded from accessing the
+data cached therein; nor is it permitted to create new files in the cache.
+
+
+There are policy source files available in:
+
+	http://people.redhat.com/~dhowells/fscache/cachefilesd-0.8.tar.bz2
+
+and later versions.  In that tarball, see the files:
+
+	cachefilesd.te
+	cachefilesd.fc
+	cachefilesd.if
+
+They are built and installed directly by the RPM.
+
+If a non-RPM based system is being used, then copy the above files to their own
+directory and run:
+
+	make -f /usr/share/selinux/devel/Makefile
+	semodule -i cachefilesd.pp
+
+You will need checkpolicy and selinux-policy-devel installed prior to the
+build.
+
+
+By default, the cache is located in /var/fscache, but if it is desirable that
+it should be elsewhere, than either the above policy files must be altered, or
+an auxiliary policy must be installed to label the alternate location of the
+cache.
+
+For instructions on how to add an auxiliary policy to enable the cache to be
+located elsewhere when SELinux is in enforcing mode, please see:
+
+	/usr/share/doc/cachefilesd-*/move-cache.txt
+
+When the cachefilesd rpm is installed; alternatively, the document can be found
+in the sources.
+
+
+==================
+A NOTE ON SECURITY
+==================
+
+CacheFiles makes use of the split security in the task_struct.  It allocates
+its own task_security structure, and redirects current->cred to point to it
+when it acts on behalf of another process, in that process's context.
+
+The reason it does this is that it calls vfs_mkdir() and suchlike rather than
+bypassing security and calling inode ops directly.  Therefore the VFS and LSM
+may deny the CacheFiles access to the cache data because under some
+circumstances the caching code is running in the security context of whatever
+process issued the original syscall on the netfs.
+
+Furthermore, should CacheFiles create a file or directory, the security
+parameters with that object is created (UID, GID, security label) would be
+derived from that process that issued the system call, thus potentially
+preventing other processes from accessing the cache - including CacheFiles's
+cache management daemon (cachefilesd).
+
+What is required is to temporarily override the security of the process that
+issued the system call.  We can't, however, just do an in-place change of the
+security data as that affects the process as an object, not just as a subject.
+This means it may lose signals or ptrace events for example, and affects what
+the process looks like in /proc.
+
+So CacheFiles makes use of a logical split in the security between the
+objective security (task->real_cred) and the subjective security (task->cred).
+The objective security holds the intrinsic security properties of a process and
+is never overridden.  This is what appears in /proc, and is what is used when a
+process is the target of an operation by some other process (SIGKILL for
+example).
+
+The subjective security holds the active security properties of a process, and
+may be overridden.  This is not seen externally, and is used whan a process
+acts upon another object, for example SIGKILLing another process or opening a
+file.
+
+LSM hooks exist that allow SELinux (or Smack or whatever) to reject a request
+for CacheFiles to run in a context of a specific security label, or to create
+files and directories with another security label.
+
+
+=======================
+STATISTICAL INFORMATION
+=======================
+
+If FS-Cache is compiled with the following option enabled:
+
+	CONFIG_CACHEFILES_HISTOGRAM=y
+
+then it will gather certain statistics and display them through a proc file.
+
+ (*) /proc/fs/cachefiles/histogram
+
+	cat /proc/fs/cachefiles/histogram
+	JIFS  SECS  LOOKUPS   MKDIRS    CREATES
+	===== ===== ========= ========= =========
+
+     This shows the breakdown of the number of times each amount of time
+     between 0 jiffies and HZ-1 jiffies a variety of tasks took to run.  The
+     columns are as follows:
+
+	COLUMN		TIME MEASUREMENT
+	=======		=======================================================
+	LOOKUPS		Length of time to perform a lookup on the backing fs
+	MKDIRS		Length of time to perform a mkdir on the backing fs
+	CREATES		Length of time to perform a create on the backing fs
+
+     Each row shows the number of events that took a particular range of times.
+     Each step is 1 jiffy in size.  The JIFS column indicates the particular
+     jiffy range covered, and the SECS field the equivalent number of seconds.
+
+
+=========
+DEBUGGING
+=========
+
+If CONFIG_CACHEFILES_DEBUG is enabled, the CacheFiles facility can have runtime
+debugging enabled by adjusting the value in:
+
+	/sys/module/cachefiles/parameters/debug
+
+This is a bitmask of debugging streams to enable:
+
+	BIT	VALUE	STREAM				POINT
+	=======	=======	===============================	=======================
+	0	1	General				Function entry trace
+	1	2					Function exit trace
+	2	4					General
+
+The appropriate set of values should be OR'd together and the result written to
+the control file.  For example:
+
+	echo $((1|4|8)) >/sys/module/cachefiles/parameters/debug
+
+will turn on all function entry debugging.

Documentation/filesystems/caching/fscache.txt

@@ -0,0 +1,333 @@
+			  ==========================
+			  General Filesystem Caching
+			  ==========================
+
+========
+OVERVIEW
+========
+
+This facility is a general purpose cache for network filesystems, though it
+could be used for caching other things such as ISO9660 filesystems too.
+
+FS-Cache mediates between cache backends (such as CacheFS) and network
+filesystems:
+
+	+---------+
+	|         |                        +--------------+
+	|   NFS   |--+                     |              |
+	|         |  |                 +-->|   CacheFS    |
+	+---------+  |   +----------+  |   |  /dev/hda5   |
+	             |   |          |  |   +--------------+
+	+---------+  +-->|          |  |
+	|         |      |          |--+
+	|   AFS   |----->| FS-Cache |
+	|         |      |          |--+
+	+---------+  +-->|          |  |
+	             |   |          |  |   +--------------+
+	+---------+  |   +----------+  |   |              |
+	|         |  |                 +-->|  CacheFiles  |
+	|  ISOFS  |--+                     |  /var/cache  |
+	|         |                        +--------------+
+	+---------+
+
+Or to look at it another way, FS-Cache is a module that provides a caching
+facility to a network filesystem such that the cache is transparent to the
+user:
+
+	+---------+
+	|         |
+	| Server  |
+	|         |
+	+---------+
+	     |                  NETWORK
+	~~~~~|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+	     |
+	     |           +----------+
+	     V           |          |
+	+---------+      |          |
+	|         |      |          |
+	|   NFS   |----->| FS-Cache |
+	|         |      |          |--+
+	+---------+      |          |  |   +--------------+   +--------------+
+	     |           |          |  |   |              |   |              |
+	     V           +----------+  +-->|  CacheFiles  |-->|  Ext3        |
+	+---------+                        |  /var/cache  |   |  /dev/sda6   |
+	|         |                        +--------------+   +--------------+
+	|   VFS   |                                ^                     ^
+	|         |                                |                     |
+	+---------+                                +--------------+      |
+	     |                  KERNEL SPACE                      |      |
+	~~~~~|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|~~~~~~|~~~~
+	     |                  USER SPACE                        |      |
+	     V                                                    |      |
+	+---------+                                           +--------------+
+	|         |                                           |              |
+	| Process |                                           | cachefilesd  |
+	|         |                                           |              |
+	+---------+                                           +--------------+
+
+
+FS-Cache does not follow the idea of completely loading every netfs file
+opened in its entirety into a cache before permitting it to be accessed and
+then serving the pages out of that cache rather than the netfs inode because:
+
+ (1) It must be practical to operate without a cache.
+
+ (2) The size of any accessible file must not be limited to the size of the
+     cache.
+
+ (3) The combined size of all opened files (this includes mapped libraries)
+     must not be limited to the size of the cache.
+
+ (4) The user should not be forced to download an entire file just to do a
+     one-off access of a small portion of it (such as might be done with the
+     "file" program).
+
+It instead serves the cache out in PAGE_SIZE chunks as and when requested by
+the netfs('s) using it.
+
+
+FS-Cache provides the following facilities:
+
+ (1) More than one cache can be used at once.  Caches can be selected
+     explicitly by use of tags.
+
+ (2) Caches can be added / removed at any time.
+
+ (3) The netfs is provided with an interface that allows either party to
+     withdraw caching facilities from a file (required for (2)).
+
+ (4) The interface to the netfs returns as few errors as possible, preferring
+     rather to let the netfs remain oblivious.
+
+ (5) Cookies are used to represent indices, files and other objects to the
+     netfs.  The simplest cookie is just a NULL pointer - indicating nothing
+     cached there.
+
+ (6) The netfs is allowed to propose - dynamically - any index hierarchy it
+     desires, though it must be aware that the index search function is
+     recursive, stack space is limited, and indices can only be children of
+     indices.
+
+ (7) Data I/O is done direct to and from the netfs's pages.  The netfs
+     indicates that page A is at index B of the data-file represented by cookie
+     C, and that it should be read or written.  The cache backend may or may
+     not start I/O on that page, but if it does, a netfs callback will be
+     invoked to indicate completion.  The I/O may be either synchronous or
+     asynchronous.
+
+ (8) Cookies can be "retired" upon release.  At this point FS-Cache will mark
+     them as obsolete and the index hierarchy rooted at that point will get
+     recycled.
+
+ (9) The netfs provides a "match" function for index searches.  In addition to
+     saying whether a match was made or not, this can also specify that an
+     entry should be updated or deleted.
+
+(10) As much as possible is done asynchronously.
+
+
+FS-Cache maintains a virtual indexing tree in which all indices, files, objects
+and pages are kept.  Bits of this tree may actually reside in one or more
+caches.
+
+                                           FSDEF
+                                             |
+                        +------------------------------------+
+                        |                                    |
+                       NFS                                  AFS
+                        |                                    |
+           +--------------------------+                +-----------+
+           |                          |                |           |
+        homedir                     mirror          afs.org   redhat.com
+           |                          |                            |
+     +------------+           +---------------+              +----------+
+     |            |           |               |              |          |
+   00001        00002       00007           00125        vol00001   vol00002
+     |            |           |               |                         |
+ +---+---+     +-----+      +---+      +------+------+            +-----+----+
+ |   |   |     |     |      |   |      |      |      |            |     |    |
+PG0 PG1 PG2   PG0  XATTR   PG0 PG1   DIRENT DIRENT DIRENT        R/W   R/O  Bak
+                     |                                            |
+                    PG0                                       +-------+
+                                                              |       |
+                                                            00001   00003
+                                                              |
+                                                          +---+---+
+                                                          |   |   |
+                                                         PG0 PG1 PG2
+
+In the example above, you can see two netfs's being backed: NFS and AFS.  These
+have different index hierarchies:
+
+ (*) The NFS primary index contains per-server indices.  Each server index is
+     indexed by NFS file handles to get data file objects.  Each data file
+     objects can have an array of pages, but may also have further child
+     objects, such as extended attributes and directory entries.  Extended
+     attribute objects themselves have page-array contents.
+
+ (*) The AFS primary index contains per-cell indices.  Each cell index contains
+     per-logical-volume indices.  Each of volume index contains up to three
+     indices for the read-write, read-only and backup mirrors of those volumes.
+     Each of these contains vnode data file objects, each of which contains an
+     array of pages.
+
+The very top index is the FS-Cache master index in which individual netfs's
+have entries.
+
+Any index object may reside in more than one cache, provided it only has index
+children.  Any index with non-index object children will be assumed to only
+reside in one cache.
+
+
+The netfs API to FS-Cache can be found in:
+
+	Documentation/filesystems/caching/netfs-api.txt
+
+The cache backend API to FS-Cache can be found in:
+
+	Documentation/filesystems/caching/backend-api.txt
+
+A description of the internal representations and object state machine can be
+found in:
+
+	Documentation/filesystems/caching/object.txt
+
+
+=======================
+STATISTICAL INFORMATION
+=======================
+
+If FS-Cache is compiled with the following options enabled:
+
+	CONFIG_FSCACHE_STATS=y
+	CONFIG_FSCACHE_HISTOGRAM=y
+
+then it will gather certain statistics and display them through a number of
+proc files.
+
+ (*) /proc/fs/fscache/stats
+
+     This shows counts of a number of events that can happen in FS-Cache:
+
+	CLASS	EVENT	MEANING
+	=======	=======	=======================================================
+	Cookies	idx=N	Number of index cookies allocated
+		dat=N	Number of data storage cookies allocated
+		spc=N	Number of special cookies allocated
+	Objects	alc=N	Number of objects allocated
+		nal=N	Number of object allocation failures
+		avl=N	Number of objects that reached the available state
+		ded=N	Number of objects that reached the dead state
+	ChkAux	non=N	Number of objects that didn't have a coherency check
+		ok=N	Number of objects that passed a coherency check
+		upd=N	Number of objects that needed a coherency data update
+		obs=N	Number of objects that were declared obsolete
+	Pages	mrk=N	Number of pages marked as being cached
+		unc=N	Number of uncache page requests seen
+	Acquire	n=N	Number of acquire cookie requests seen
+		nul=N	Number of acq reqs given a NULL parent
+		noc=N	Number of acq reqs rejected due to no cache available
+		ok=N	Number of acq reqs succeeded
+		nbf=N	Number of acq reqs rejected due to error
+		oom=N	Number of acq reqs failed on ENOMEM
+	Lookups	n=N	Number of lookup calls made on cache backends
+		neg=N	Number of negative lookups made
+		pos=N	Number of positive lookups made
+		crt=N	Number of objects created by lookup
+	Updates	n=N	Number of update cookie requests seen
+		nul=N	Number of upd reqs given a NULL parent
+		run=N	Number of upd reqs granted CPU time
+	Relinqs	n=N	Number of relinquish cookie requests seen
+		nul=N	Number of rlq reqs given a NULL parent
+		wcr=N	Number of rlq reqs waited on completion of creation
+	AttrChg	n=N	Number of attribute changed requests seen
+		ok=N	Number of attr changed requests queued
+		nbf=N	Number of attr changed rejected -ENOBUFS
+		oom=N	Number of attr changed failed -ENOMEM
+		run=N	Number of attr changed ops given CPU time
+	Allocs	n=N	Number of allocation requests seen
+		ok=N	Number of successful alloc reqs
+		wt=N	Number of alloc reqs that waited on lookup completion
+		nbf=N	Number of alloc reqs rejected -ENOBUFS
+		ops=N	Number of alloc reqs submitted
+		owt=N	Number of alloc reqs waited for CPU time
+	Retrvls	n=N	Number of retrieval (read) requests seen
+		ok=N	Number of successful retr reqs
+		wt=N	Number of retr reqs that waited on lookup completion
+		nod=N	Number of retr reqs returned -ENODATA
+		nbf=N	Number of retr reqs rejected -ENOBUFS
+		int=N	Number of retr reqs aborted -ERESTARTSYS
+		oom=N	Number of retr reqs failed -ENOMEM
+		ops=N	Number of retr reqs submitted
+		owt=N	Number of retr reqs waited for CPU time
+	Stores	n=N	Number of storage (write) requests seen
+		ok=N	Number of successful store reqs
+		agn=N	Number of store reqs on a page already pending storage
+		nbf=N	Number of store reqs rejected -ENOBUFS
+		oom=N	Number of store reqs failed -ENOMEM
+		ops=N	Number of store reqs submitted
+		run=N	Number of store reqs granted CPU time
+	Ops	pend=N	Number of times async ops added to pending queues
+		run=N	Number of times async ops given CPU time
+		enq=N	Number of times async ops queued for processing
+		dfr=N	Number of async ops queued for deferred release
+		rel=N	Number of async ops released
+		gc=N	Number of deferred-release async ops garbage collected
+
+
+ (*) /proc/fs/fscache/histogram
+
+	cat /proc/fs/fscache/histogram
+	JIFS  SECS  OBJ INST  OP RUNS   OBJ RUNS  RETRV DLY RETRIEVLS
+	===== ===== ========= ========= ========= ========= =========
+
+     This shows the breakdown of the number of times each amount of time
+     between 0 jiffies and HZ-1 jiffies a variety of tasks took to run.  The
+     columns are as follows:
+
+	COLUMN		TIME MEASUREMENT
+	=======		=======================================================
+	OBJ INST	Length of time to instantiate an object
+	OP RUNS		Length of time a call to process an operation took
+	OBJ RUNS	Length of time a call to process an object event took
+	RETRV DLY	Time between an requesting a read and lookup completing
+	RETRIEVLS	Time between beginning and end of a retrieval
+
+     Each row shows the number of events that took a particular range of times.
+     Each step is 1 jiffy in size.  The JIFS column indicates the particular
+     jiffy range covered, and the SECS field the equivalent number of seconds.
+
+
+=========
+DEBUGGING
+=========
+
+If CONFIG_FSCACHE_DEBUG is enabled, the FS-Cache facility can have runtime
+debugging enabled by adjusting the value in:
+
+	/sys/module/fscache/parameters/debug
+
+This is a bitmask of debugging streams to enable:
+
+	BIT	VALUE	STREAM				POINT
+	=======	=======	===============================	=======================
+	0	1	Cache management		Function entry trace
+	1	2					Function exit trace
+	2	4					General
+	3	8	Cookie management		Function entry trace
+	4	16					Function exit trace
+	5	32					General
+	6	64	Page handling			Function entry trace
+	7	128					Function exit trace
+	8	256					General
+	9	512	Operation management		Function entry trace
+	10	1024					Function exit trace
+	11	2048					General
+
+The appropriate set of values should be OR'd together and the result written to
+the control file.  For example:
+
+	echo $((1|8|64)) >/sys/module/fscache/parameters/debug
+
+will turn on all function entry debugging.

Documentation/filesystems/caching/netfs-api.txt

@@ -0,0 +1,778 @@
+			===============================
+			FS-CACHE NETWORK FILESYSTEM API
+			===============================
+
+There's an API by which a network filesystem can make use of the FS-Cache
+facilities.  This is based around a number of principles:
+
+ (1) Caches can store a number of different object types.  There are two main
+     object types: indices and files.  The first is a special type used by
+     FS-Cache to make finding objects faster and to make retiring of groups of
+     objects easier.
+
+ (2) Every index, file or other object is represented by a cookie.  This cookie
+     may or may not have anything associated with it, but the netfs doesn't
+     need to care.
+
+ (3) Barring the top-level index (one entry per cached netfs), the index
+     hierarchy for each netfs is structured according the whim of the netfs.
+
+This API is declared in <linux/fscache.h>.
+
+This document contains the following sections:
+
+	 (1) Network filesystem definition
+	 (2) Index definition
+	 (3) Object definition
+	 (4) Network filesystem (un)registration
+	 (5) Cache tag lookup
+	 (6) Index registration
+	 (7) Data file registration
+	 (8) Miscellaneous object registration
+	 (9) Setting the data file size
+	(10) Page alloc/read/write
+	(11) Page uncaching
+	(12) Index and data file update
+	(13) Miscellaneous cookie operations
+	(14) Cookie unregistration
+	(15) Index and data file invalidation
+	(16) FS-Cache specific page flags.
+
+
+=============================
+NETWORK FILESYSTEM DEFINITION
+=============================
+
+FS-Cache needs a description of the network filesystem.  This is specified
+using a record of the following structure:
+
+	struct fscache_netfs {
+		uint32_t			version;
+		const char			*name;
+		struct fscache_cookie		*primary_index;
+		...
+	};
+
+This first two fields should be filled in before registration, and the third
+will be filled in by the registration function; any other fields should just be
+ignored and are for internal use only.
+
+The fields are:
+
+ (1) The name of the netfs (used as the key in the toplevel index).
+
+ (2) The version of the netfs (if the name matches but the version doesn't, the
+     entire in-cache hierarchy for this netfs will be scrapped and begun
+     afresh).
+
+ (3) The cookie representing the primary index will be allocated according to
+     another parameter passed into the registration function.
+
+For example, kAFS (linux/fs/afs/) uses the following definitions to describe
+itself:
+
+	struct fscache_netfs afs_cache_netfs = {
+		.version	= 0,
+		.name		= "afs",
+	};
+
+
+================
+INDEX DEFINITION
+================
+
+Indices are used for two purposes:
+
+ (1) To aid the finding of a file based on a series of keys (such as AFS's
+     "cell", "volume ID", "vnode ID").
+
+ (2) To make it easier to discard a subset of all the files cached based around
+     a particular key - for instance to mirror the removal of an AFS volume.
+
+However, since it's unlikely that any two netfs's are going to want to define
+their index hierarchies in quite the same way, FS-Cache tries to impose as few
+restraints as possible on how an index is structured and where it is placed in
+the tree.  The netfs can even mix indices and data files at the same level, but
+it's not recommended.
+
+Each index entry consists of a key of indeterminate length plus some auxilliary
+data, also of indeterminate length.
+
+There are some limits on indices:
+
+ (1) Any index containing non-index objects should be restricted to a single
+     cache.  Any such objects created within an index will be created in the
+     first cache only.  The cache in which an index is created can be
+     controlled by cache tags (see below).
+
+ (2) The entry data must be atomically journallable, so it is limited to about
+     400 bytes at present.  At least 400 bytes will be available.
+
+ (3) The depth of the index tree should be judged with care as the search
+     function is recursive.  Too many layers will run the kernel out of stack.
+
+
+=================
+OBJECT DEFINITION
+=================
+
+To define an object, a structure of the following type should be filled out:
+
+	struct fscache_cookie_def
+	{
+		uint8_t name[16];
+		uint8_t type;
+
+		struct fscache_cache_tag *(*select_cache)(
+			const void *parent_netfs_data,
+			const void *cookie_netfs_data);
+
+		uint16_t (*get_key)(const void *cookie_netfs_data,
+				    void *buffer,
+				    uint16_t bufmax);
+
+		void (*get_attr)(const void *cookie_netfs_data,
+				 uint64_t *size);
+
+		uint16_t (*get_aux)(const void *cookie_netfs_data,
+				    void *buffer,
+				    uint16_t bufmax);
+
+		enum fscache_checkaux (*check_aux)(void *cookie_netfs_data,
+						   const void *data,
+						   uint16_t datalen);
+
+		void (*get_context)(void *cookie_netfs_data, void *context);
+
+		void (*put_context)(void *cookie_netfs_data, void *context);
+
+		void (*mark_pages_cached)(void *cookie_netfs_data,
+					  struct address_space *mapping,
+					  struct pagevec *cached_pvec);
+
+		void (*now_uncached)(void *cookie_netfs_data);
+	};
+
+This has the following fields:
+
+ (1) The type of the object [mandatory].
+
+     This is one of the following values:
+
+	(*) FSCACHE_COOKIE_TYPE_INDEX
+
+	    This defines an index, which is a special FS-Cache type.
+
+	(*) FSCACHE_COOKIE_TYPE_DATAFILE
+
+	    This defines an ordinary data file.
+
+	(*) Any other value between 2 and 255
+
+	    This defines an extraordinary object such as an XATTR.
+
+ (2) The name of the object type (NUL terminated unless all 16 chars are used)
+     [optional].
+
+ (3) A function to select the cache in which to store an index [optional].
+
+     This function is invoked when an index needs to be instantiated in a cache
+     during the instantiation of a non-index object.  Only the immediate index
+     parent for the non-index object will be queried.  Any indices above that
+     in the hierarchy may be stored in multiple caches.  This function does not
+     need to be supplied for any non-index object or any index that will only
+     have index children.
+
+     If this function is not supplied or if it returns NULL then the first
+     cache in the parent's list will be chosed, or failing that, the first
+     cache in the master list.
+
+ (4) A function to retrieve an object's key from the netfs [mandatory].
+
+     This function will be called with the netfs data that was passed to the
+     cookie acquisition function and the maximum length of key data that it may
+     provide.  It should write the required key data into the given buffer and
+     return the quantity it wrote.
+
+ (5) A function to retrieve attribute data from the netfs [optional].
+
+     This function will be called with the netfs data that was passed to the
+     cookie acquisition function.  It should return the size of the file if
+     this is a data file.  The size may be used to govern how much cache must
+     be reserved for this file in the cache.
+
+     If the function is absent, a file size of 0 is assumed.
+
+ (6) A function to retrieve auxilliary data from the netfs [optional].
+
+     This function will be called with the netfs data that was passed to the
+     cookie acquisition function and the maximum length of auxilliary data that
+     it may provide.  It should write the auxilliary data into the given buffer
+     and return the quantity it wrote.
+
+     If this function is absent, the auxilliary data length will be set to 0.
+
+     The length of the auxilliary data buffer may be dependent on the key
+     length.  A netfs mustn't rely on being able to provide more than 400 bytes
+     for both.
+
+ (7) A function to check the auxilliary data [optional].
+
+     This function will be called to check that a match found in the cache for
+     this object is valid.  For instance with AFS it could check the auxilliary
+     data against the data version number returned by the server to determine
+     whether the index entry in a cache is still valid.
+
+     If this function is absent, it will be assumed that matching objects in a
+     cache are always valid.
+
+     If present, the function should return one of the following values:
+
+	(*) FSCACHE_CHECKAUX_OKAY		- the entry is okay as is
+	(*) FSCACHE_CHECKAUX_NEEDS_UPDATE	- the entry requires update
+	(*) FSCACHE_CHECKAUX_OBSOLETE		- the entry should be deleted
+
+     This function can also be used to extract data from the auxilliary data in
+     the cache and copy it into the netfs's structures.
+
+ (8) A pair of functions to manage contexts for the completion callback
+     [optional].
+
+     The cache read/write functions are passed a context which is then passed
+     to the I/O completion callback function.  To ensure this context remains
+     valid until after the I/O completion is called, two functions may be
+     provided: one to get an extra reference on the context, and one to drop a
+     reference to it.
+
+     If the context is not used or is a type of object that won't go out of
+     scope, then these functions are not required.  These functions are not
+     required for indices as indices may not contain data.  These functions may
+     be called in interrupt context and so may not sleep.
+
+ (9) A function to mark a page as retaining cache metadata [optional].
+
+     This is called by the cache to indicate that it is retaining in-memory
+     information for this page and that the netfs should uncache the page when
+     it has finished.  This does not indicate whether there's data on the disk
+     or not.  Note that several pages at once may be presented for marking.
+
+     The PG_fscache bit is set on the pages before this function would be
+     called, so the function need not be provided if this is sufficient.
+
+     This function is not required for indices as they're not permitted data.
+
+(10) A function to unmark all the pages retaining cache metadata [mandatory].
+
+     This is called by FS-Cache to indicate that a backing store is being
+     unbound from a cookie and that all the marks on the pages should be
+     cleared to prevent confusion.  Note that the cache will have torn down all
+     its tracking information so that the pages don't need to be explicitly
+     uncached.
+
+     This function is not required for indices as they're not permitted data.
+
+
+===================================
+NETWORK FILESYSTEM (UN)REGISTRATION
+===================================
+
+The first step is to declare the network filesystem to the cache.  This also
+involves specifying the layout of the primary index (for AFS, this would be the
+"cell" level).
+
+The registration function is:
+
+	int fscache_register_netfs(struct fscache_netfs *netfs);
+
+It just takes a pointer to the netfs definition.  It returns 0 or an error as
+appropriate.
+
+For kAFS, registration is done as follows:
+
+	ret = fscache_register_netfs(&afs_cache_netfs);
+
+The last step is, of course, unregistration:
+
+	void fscache_unregister_netfs(struct fscache_netfs *netfs);
+
+
+================
+CACHE TAG LOOKUP
+================
+
+FS-Cache permits the use of more than one cache.  To permit particular index
+subtrees to be bound to particular caches, the second step is to look up cache
+representation tags.  This step is optional; it can be left entirely up to
+FS-Cache as to which cache should be used.  The problem with doing that is that
+FS-Cache will always pick the first cache that was registered.
+
+To get the representation for a named tag:
+
+	struct fscache_cache_tag *fscache_lookup_cache_tag(const char *name);
+
+This takes a text string as the name and returns a representation of a tag.  It
+will never return an error.  It may return a dummy tag, however, if it runs out
+of memory; this will inhibit caching with this tag.
+
+Any representation so obtained must be released by passing it to this function:
+
+	void fscache_release_cache_tag(struct fscache_cache_tag *tag);
+
+The tag will be retrieved by FS-Cache when it calls the object definition
+operation select_cache().
+
+
+==================
+INDEX REGISTRATION
+==================
+
+The third step is to inform FS-Cache about part of an index hierarchy that can
+be used to locate files.  This is done by requesting a cookie for each index in
+the path to the file:
+
+	struct fscache_cookie *
+	fscache_acquire_cookie(struct fscache_cookie *parent,
+			       const struct fscache_object_def *def,
+			       void *netfs_data);
+
+This function creates an index entry in the index represented by parent,
+filling in the index entry by calling the operations pointed to by def.
+
+Note that this function never returns an error - all errors are handled
+internally.  It may, however, return NULL to indicate no cookie.  It is quite
+acceptable to pass this token back to this function as the parent to another
+acquisition (or even to the relinquish cookie, read page and write page
+functions - see below).
+
+Note also that no indices are actually created in a cache until a non-index
+object needs to be created somewhere down the hierarchy.  Furthermore, an index
+may be created in several different caches independently at different times.
+This is all handled transparently, and the netfs doesn't see any of it.
+
+For example, with AFS, a cell would be added to the primary index.  This index
+entry would have a dependent inode containing a volume location index for the
+volume mappings within this cell:
+
+	cell->cache =
+		fscache_acquire_cookie(afs_cache_netfs.primary_index,
+				       &afs_cell_cache_index_def,
+				       cell);
+
+Then when a volume location was accessed, it would be entered into the cell's
+index and an inode would be allocated that acts as a volume type and hash chain
+combination:
+
+	vlocation->cache =
+		fscache_acquire_cookie(cell->cache,
+				       &afs_vlocation_cache_index_def,
+				       vlocation);
+
+And then a particular flavour of volume (R/O for example) could be added to
+that index, creating another index for vnodes (AFS inode equivalents):
+
+	volume->cache =
+		fscache_acquire_cookie(vlocation->cache,
+				       &afs_volume_cache_index_def,
+				       volume);
+
+
+======================
+DATA FILE REGISTRATION
+======================
+
+The fourth step is to request a data file be created in the cache.  This is
+identical to index cookie acquisition.  The only difference is that the type in
+the object definition should be something other than index type.
+
+	vnode->cache =
+		fscache_acquire_cookie(volume->cache,
+				       &afs_vnode_cache_object_def,
+				       vnode);
+
+
+=================================
+MISCELLANEOUS OBJECT REGISTRATION
+=================================
+
+An optional step is to request an object of miscellaneous type be created in
+the cache.  This is almost identical to index cookie acquisition.  The only
+difference is that the type in the object definition should be something other
+than index type.  Whilst the parent object could be an index, it's more likely
+it would be some other type of object such as a data file.
+
+	xattr->cache =
+		fscache_acquire_cookie(vnode->cache,
+				       &afs_xattr_cache_object_def,
+				       xattr);
+
+Miscellaneous objects might be used to store extended attributes or directory
+entries for example.
+
+
+==========================
+SETTING THE DATA FILE SIZE
+==========================
+
+The fifth step is to set the physical attributes of the file, such as its size.
+This doesn't automatically reserve any space in the cache, but permits the
+cache to adjust its metadata for data tracking appropriately:
+
+	int fscache_attr_changed(struct fscache_cookie *cookie);
+
+The cache will return -ENOBUFS if there is no backing cache or if there is no
+space to allocate any extra metadata required in the cache.  The attributes
+will be accessed with the get_attr() cookie definition operation.
+
+Note that attempts to read or write data pages in the cache over this size may
+be rebuffed with -ENOBUFS.
+
+This operation schedules an attribute adjustment to happen asynchronously at
+some point in the future, and as such, it may happen after the function returns
+to the caller.  The attribute adjustment excludes read and write operations.
+
+
+=====================
+PAGE READ/ALLOC/WRITE
+=====================
+
+And the sixth step is to store and retrieve pages in the cache.  There are
+three functions that are used to do this.
+
+Note:
+
+ (1) A page should not be re-read or re-allocated without uncaching it first.
+
+ (2) A read or allocated page must be uncached when the netfs page is released
+     from the pagecache.
+
+ (3) A page should only be written to the cache if previous read or allocated.
+
+This permits the cache to maintain its page tracking in proper order.
+
+
+PAGE READ
+---------
+
+Firstly, the netfs should ask FS-Cache to examine the caches and read the
+contents cached for a particular page of a particular file if present, or else
+allocate space to store the contents if not:
+
+	typedef
+	void (*fscache_rw_complete_t)(struct page *page,
+				      void *context,
+				      int error);
+
+	int fscache_read_or_alloc_page(struct fscache_cookie *cookie,
+				       struct page *page,
+				       fscache_rw_complete_t end_io_func,
+				       void *context,
+				       gfp_t gfp);
+
+The cookie argument must specify a cookie for an object that isn't an index,
+the page specified will have the data loaded into it (and is also used to
+specify the page number), and the gfp argument is used to control how any
+memory allocations made are satisfied.
+
+If the cookie indicates the inode is not cached:
+
+ (1) The function will return -ENOBUFS.
+
+Else if there's a copy of the page resident in the cache:
+
+ (1) The mark_pages_cached() cookie operation will be called on that page.
+
+ (2) The function will submit a request to read the data from the cache's
+     backing device directly into the page specified.
+
+ (3) The function will return 0.
+
+ (4) When the read is complete, end_io_func() will be invoked with:
+
+     (*) The netfs data supplied when the cookie was created.
+
+     (*) The page descriptor.
+
+     (*) The context argument passed to the above function.  This will be
+         maintained with the get_context/put_context functions mentioned above.
+
+     (*) An argument that's 0 on success or negative for an error code.
+
+     If an error occurs, it should be assumed that the page contains no usable
+     data.
+
+     end_io_func() will be called in process context if the read is results in
+     an error, but it might be called in interrupt context if the read is
+     successful.
+
+Otherwise, if there's not a copy available in cache, but the cache may be able
+to store the page:
+
+ (1) The mark_pages_cached() cookie operation will be called on that page.
+
+ (2) A block may be reserved in the cache and attached to the object at the
+     appropriate place.
+
+ (3) The function will return -ENODATA.
+
+This function may also return -ENOMEM or -EINTR, in which case it won't have
+read any data from the cache.
+
+
+PAGE ALLOCATE
+-------------
+
+Alternatively, if there's not expected to be any data in the cache for a page
+because the file has been extended, a block can simply be allocated instead:
+
+	int fscache_alloc_page(struct fscache_cookie *cookie,
+			       struct page *page,
+			       gfp_t gfp);
+
+This is similar to the fscache_read_or_alloc_page() function, except that it
+never reads from the cache.  It will return 0 if a block has been allocated,
+rather than -ENODATA as the other would.  One or the other must be performed
+before writing to the cache.
+
+The mark_pages_cached() cookie operation will be called on the page if
+successful.
+
+
+PAGE WRITE
+----------
+
+Secondly, if the netfs changes the contents of the page (either due to an
+initial download or if a user performs a write), then the page should be
+written back to the cache:
+
+	int fscache_write_page(struct fscache_cookie *cookie,
+			       struct page *page,
+			       gfp_t gfp);
+
+The cookie argument must specify a data file cookie, the page specified should
+contain the data to be written (and is also used to specify the page number),
+and the gfp argument is used to control how any memory allocations made are
+satisfied.
+
+The page must have first been read or allocated successfully and must not have
+been uncached before writing is performed.
+
+If the cookie indicates the inode is not cached then:
+
+ (1) The function will return -ENOBUFS.
+
+Else if space can be allocated in the cache to hold this page:
+
+ (1) PG_fscache_write will be set on the page.
+
+ (2) The function will submit a request to write the data to cache's backing
+     device directly from the page specified.
+
+ (3) The function will return 0.
+
+ (4) When the write is complete PG_fscache_write is cleared on the page and
+     anyone waiting for that bit will be woken up.
+
+Else if there's no space available in the cache, -ENOBUFS will be returned.  It
+is also possible for the PG_fscache_write bit to be cleared when no write took
+place if unforeseen circumstances arose (such as a disk error).
+
+Writing takes place asynchronously.
+
+
+MULTIPLE PAGE READ
+------------------
+
+A facility is provided to read several pages at once, as requested by the
+readpages() address space operation:
+
+	int fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
+					struct address_space *mapping,
+					struct list_head *pages,
+					int *nr_pages,
+					fscache_rw_complete_t end_io_func,
+					void *context,
+					gfp_t gfp);
+
+This works in a similar way to fscache_read_or_alloc_page(), except:
+
+ (1) Any page it can retrieve data for is removed from pages and nr_pages and
+     dispatched for reading to the disk.  Reads of adjacent pages on disk may
+     be merged for greater efficiency.
+
+ (2) The mark_pages_cached() cookie operation will be called on several pages
+     at once if they're being read or allocated.
+
+ (3) If there was an general error, then that error will be returned.
+
+     Else if some pages couldn't be allocated or read, then -ENOBUFS will be
+     returned.
+
+     Else if some pages couldn't be read but were allocated, then -ENODATA will
+     be returned.
+
+     Otherwise, if all pages had reads dispatched, then 0 will be returned, the
+     list will be empty and *nr_pages will be 0.
+
+ (4) end_io_func will be called once for each page being read as the reads
+     complete.  It will be called in process context if error != 0, but it may
+     be called in interrupt context if there is no error.
+
+Note that a return of -ENODATA, -ENOBUFS or any other error does not preclude
+some of the pages being read and some being allocated.  Those pages will have
+been marked appropriately and will need uncaching.
+
+
+==============
+PAGE UNCACHING
+==============
+
+To uncache a page, this function should be called:
+
+	void fscache_uncache_page(struct fscache_cookie *cookie,
+				  struct page *page);
+
+This function permits the cache to release any in-memory representation it
+might be holding for this netfs page.  This function must be called once for
+each page on which the read or write page functions above have been called to
+make sure the cache's in-memory tracking information gets torn down.
+
+Note that pages can't be explicitly deleted from the a data file.  The whole
+data file must be retired (see the relinquish cookie function below).
+
+Furthermore, note that this does not cancel the asynchronous read or write
+operation started by the read/alloc and write functions, so the page
+invalidation and release functions must use:
+
+	bool fscache_check_page_write(struct fscache_cookie *cookie,
+				      struct page *page);
+
+to see if a page is being written to the cache, and:
+
+	void fscache_wait_on_page_write(struct fscache_cookie *cookie,
+					struct page *page);
+
+to wait for it to finish if it is.
+
+
+==========================
+INDEX AND DATA FILE UPDATE
+==========================
+
+To request an update of the index data for an index or other object, the
+following function should be called:
+
+	void fscache_update_cookie(struct fscache_cookie *cookie);
+
+This function will refer back to the netfs_data pointer stored in the cookie by
+the acquisition function to obtain the data to write into each revised index
+entry.  The update method in the parent index definition will be called to
+transfer the data.
+
+Note that partial updates may happen automatically at other times, such as when
+data blocks are added to a data file object.
+
+
+===============================
+MISCELLANEOUS COOKIE OPERATIONS
+===============================
+
+There are a number of operations that can be used to control cookies:
+
+ (*) Cookie pinning:
+
+	int fscache_pin_cookie(struct fscache_cookie *cookie);
+	void fscache_unpin_cookie(struct fscache_cookie *cookie);
+
+     These operations permit data cookies to be pinned into the cache and to
+     have the pinning removed.  They are not permitted on index cookies.
+
+     The pinning function will return 0 if successful, -ENOBUFS in the cookie
+     isn't backed by a cache, -EOPNOTSUPP if the cache doesn't support pinning,
+     -ENOSPC if there isn't enough space to honour the operation, -ENOMEM or
+     -EIO if there's any other problem.
+
+ (*) Data space reservation:
+
+	int fscache_reserve_space(struct fscache_cookie *cookie, loff_t size);
+
+     This permits a netfs to request cache space be reserved to store up to the
+     given amount of a file.  It is permitted to ask for more than the current
+     size of the file to allow for future file expansion.
+
+     If size is given as zero then the reservation will be cancelled.
+
+     The function will return 0 if successful, -ENOBUFS in the cookie isn't
+     backed by a cache, -EOPNOTSUPP if the cache doesn't support reservations,
+     -ENOSPC if there isn't enough space to honour the operation, -ENOMEM or
+     -EIO if there's any other problem.
+
+     Note that this doesn't pin an object in a cache; it can still be culled to
+     make space if it's not in use.
+
+
+=====================
+COOKIE UNREGISTRATION
+=====================
+
+To get rid of a cookie, this function should be called.
+
+	void fscache_relinquish_cookie(struct fscache_cookie *cookie,
+				       int retire);
+
+If retire is non-zero, then the object will be marked for recycling, and all
+copies of it will be removed from all active caches in which it is present.
+Not only that but all child objects will also be retired.
+
+If retire is zero, then the object may be available again when next the
+acquisition function is called.  Retirement here will overrule the pinning on a
+cookie.
+
+One very important note - relinquish must NOT be called for a cookie unless all
+the cookies for "child" indices, objects and pages have been relinquished
+first.
+
+
+================================
+INDEX AND DATA FILE INVALIDATION
+================================
+
+There is no direct way to invalidate an index subtree or a data file.  To do
+this, the caller should relinquish and retire the cookie they have, and then
+acquire a new one.
+
+
+===========================
+FS-CACHE SPECIFIC PAGE FLAG
+===========================
+
+FS-Cache makes use of a page flag, PG_private_2, for its own purpose.  This is
+given the alternative name PG_fscache.
+
+PG_fscache is used to indicate that the page is known by the cache, and that
+the cache must be informed if the page is going to go away.  It's an indication
+to the netfs that the cache has an interest in this page, where an interest may
+be a pointer to it, resources allocated or reserved for it, or I/O in progress
+upon it.
+
+The netfs can use this information in methods such as releasepage() to
+determine whether it needs to uncache a page or update it.
+
+Furthermore, if this bit is set, releasepage() and invalidatepage() operations
+will be called on a page to get rid of it, even if PG_private is not set.  This
+allows caching to attempted on a page before read_cache_pages() to be called
+after fscache_read_or_alloc_pages() as the former will try and release pages it
+was given under certain circumstances.
+
+This bit does not overlap with such as PG_private.  This means that FS-Cache
+can be used with a filesystem that uses the block buffering code.
+
+There are a number of operations defined on this flag:
+
+	int PageFsCache(struct page *page);
+	void SetPageFsCache(struct page *page)
+	void ClearPageFsCache(struct page *page)
+	int TestSetPageFsCache(struct page *page)
+	int TestClearPageFsCache(struct page *page)
+
+These functions are bit test, bit set, bit clear, bit test and set and bit
+test and clear operations on PG_fscache.

Documentation/filesystems/caching/object.txt

@@ -0,0 +1,313 @@
+	     ====================================================
+	     IN-KERNEL CACHE OBJECT REPRESENTATION AND MANAGEMENT
+	     ====================================================
+
+By: David Howells <dhowells@redhat.com>
+
+Contents:
+
+ (*) Representation
+
+ (*) Object management state machine.
+
+     - Provision of cpu time.
+     - Locking simplification.
+
+ (*) The set of states.
+
+ (*) The set of events.
+
+
+==============
+REPRESENTATION
+==============
+
+FS-Cache maintains an in-kernel representation of each object that a netfs is
+currently interested in.  Such objects are represented by the fscache_cookie
+struct and are referred to as cookies.
+
+FS-Cache also maintains a separate in-kernel representation of the objects that
+a cache backend is currently actively caching.  Such objects are represented by
+the fscache_object struct.  The cache backends allocate these upon request, and
+are expected to embed them in their own representations.  These are referred to
+as objects.
+
+There is a 1:N relationship between cookies and objects.  A cookie may be
+represented by multiple objects - an index may exist in more than one cache -
+or even by no objects (it may not be cached).
+
+Furthermore, both cookies and objects are hierarchical.  The two hierarchies
+correspond, but the cookies tree is a superset of the union of the object trees
+of multiple caches:
+
+	    NETFS INDEX TREE               :      CACHE 1     :      CACHE 2
+	                                   :                  :
+	                                   :   +-----------+  :
+	                          +----------->|  IObject  |  :
+	      +-----------+       |        :   +-----------+  :
+	      |  ICookie  |-------+        :         |        :
+	      +-----------+       |        :         |        :   +-----------+
+	            |             +------------------------------>|  IObject  |
+	            |                      :         |        :   +-----------+
+	            |                      :         V        :         |
+	            |                      :   +-----------+  :         |
+	            V             +----------->|  IObject  |  :         |
+	      +-----------+       |        :   +-----------+  :         |
+	      |  ICookie  |-------+        :         |        :         V
+	      +-----------+       |        :         |        :   +-----------+
+	            |             +------------------------------>|  IObject  |
+	      +-----+-----+                :         |        :   +-----------+
+	      |           |                :         |        :         |
+	      V           |                :         V        :         |
+	+-----------+     |                :   +-----------+  :         |
+	|  ICookie  |------------------------->|  IObject  |  :         |
+	+-----------+     |                :   +-----------+  :         |
+	      |           V                :         |        :         V
+	      |     +-----------+          :         |        :   +-----------+
+	      |     |  ICookie  |-------------------------------->|  IObject  |
+	      |     +-----------+          :         |        :   +-----------+
+	      V           |                :         V        :         |
+	+-----------+     |                :   +-----------+  :         |
+	|  DCookie  |------------------------->|  DObject  |  :         |
+	+-----------+     |                :   +-----------+  :         |
+	                  |                :                  :         |
+	          +-------+-------+        :                  :         |
+	          |               |        :                  :         |
+	          V               V        :                  :         V
+	    +-----------+   +-----------+  :                  :   +-----------+
+	    |  DCookie  |   |  DCookie  |------------------------>|  DObject  |
+	    +-----------+   +-----------+  :                  :   +-----------+
+	                                   :                  :
+
+In the above illustration, ICookie and IObject represent indices and DCookie
+and DObject represent data storage objects.  Indices may have representation in
+multiple caches, but currently, non-index objects may not.  Objects of any type
+may also be entirely unrepresented.
+
+As far as the netfs API goes, the netfs is only actually permitted to see
+pointers to the cookies.  The cookies themselves and any objects attached to
+those cookies are hidden from it.
+
+
+===============================
+OBJECT MANAGEMENT STATE MACHINE
+===============================
+
+Within FS-Cache, each active object is managed by its own individual state
+machine.  The state for an object is kept in the fscache_object struct, in
+object->state.  A cookie may point to a set of objects that are in different
+states.
+
+Each state has an action associated with it that is invoked when the machine
+wakes up in that state.  There are four logical sets of states:
+
+ (1) Preparation: states that wait for the parent objects to become ready.  The
+     representations are hierarchical, and it is expected that an object must
+     be created or accessed with respect to its parent object.
+
+ (2) Initialisation: states that perform lookups in the cache and validate
+     what's found and that create on disk any missing metadata.
+
+ (3) Normal running: states that allow netfs operations on objects to proceed
+     and that update the state of objects.
+
+ (4) Termination: states that detach objects from their netfs cookies, that
+     delete objects from disk, that handle disk and system errors and that free
+     up in-memory resources.
+
+
+In most cases, transitioning between states is in response to signalled events.
+When a state has finished processing, it will usually set the mask of events in
+which it is interested (object->event_mask) and relinquish the worker thread.
+Then when an event is raised (by calling fscache_raise_event()), if the event
+is not masked, the object will be queued for processing (by calling
+fscache_enqueue_object()).
+
+
+PROVISION OF CPU TIME
+---------------------
+
+The work to be done by the various states is given CPU time by the threads of
+the slow work facility (see Documentation/slow-work.txt).  This is used in
+preference to the workqueue facility because:
+
+ (1) Threads may be completely occupied for very long periods of time by a
+     particular work item.  These state actions may be doing sequences of
+     synchronous, journalled disk accesses (lookup, mkdir, create, setxattr,
+     getxattr, truncate, unlink, rmdir, rename).
+
+ (2) Threads may do little actual work, but may rather spend a lot of time
+     sleeping on I/O.  This means that single-threaded and 1-per-CPU-threaded
+     workqueues don't necessarily have the right numbers of threads.
+
+
+LOCKING SIMPLIFICATION
+----------------------
+
+Because only one worker thread may be operating on any particular object's
+state machine at once, this simplifies the locking, particularly with respect
+to disconnecting the netfs's representation of a cache object (fscache_cookie)
+from the cache backend's representation (fscache_object) - which may be
+requested from either end.
+
+
+=================
+THE SET OF STATES
+=================
+
+The object state machine has a set of states that it can be in.  There are
+preparation states in which the object sets itself up and waits for its parent
+object to transit to a state that allows access to its children:
+
+ (1) State FSCACHE_OBJECT_INIT.
+
+     Initialise the object and wait for the parent object to become active.  In
+     the cache, it is expected that it will not be possible to look an object
+     up from the parent object, until that parent object itself has been looked
+     up.
+
+There are initialisation states in which the object sets itself up and accesses
+disk for the object metadata:
+
+ (2) State FSCACHE_OBJECT_LOOKING_UP.
+
+     Look up the object on disk, using the parent as a starting point.
+     FS-Cache expects the cache backend to probe the cache to see whether this
+     object is represented there, and if it is, to see if it's valid (coherency
+     management).
+
+     The cache should call fscache_object_lookup_negative() to indicate lookup
+     failure for whatever reason, and should call fscache_obtained_object() to
+     indicate success.
+
+     At the completion of lookup, FS-Cache will let the netfs go ahead with
+     read operations, no matter whether the file is yet cached.  If not yet
+     cached, read operations will be immediately rejected with ENODATA until
+     the first known page is uncached - as to that point there can be no data
+     to be read out of the cache for that file that isn't currently also held
+     in the pagecache.
+
+ (3) State FSCACHE_OBJECT_CREATING.
+
+     Create an object on disk, using the parent as a starting point.  This
+     happens if the lookup failed to find the object, or if the object's
+     coherency data indicated what's on disk is out of date.  In this state,
+     FS-Cache expects the cache to create
+
+     The cache should call fscache_obtained_object() if creation completes
+     successfully, fscache_object_lookup_negative() otherwise.
+
+     At the completion of creation, FS-Cache will start processing write
+     operations the netfs has queued for an object.  If creation failed, the
+     write ops will be transparently discarded, and nothing recorded in the
+     cache.
+
+There are some normal running states in which the object spends its time
+servicing netfs requests:
+
+ (4) State FSCACHE_OBJECT_AVAILABLE.
+
+     A transient state in which pending operations are started, child objects
+     are permitted to advance from FSCACHE_OBJECT_INIT state, and temporary
+     lookup data is freed.
+
+ (5) State FSCACHE_OBJECT_ACTIVE.
+
+     The normal running state.  In this state, requests the netfs makes will be
+     passed on to the cache.
+
+ (6) State FSCACHE_OBJECT_UPDATING.
+
+     The state machine comes here to update the object in the cache from the
+     netfs's records.  This involves updating the auxiliary data that is used
+     to maintain coherency.
+
+And there are terminal states in which an object cleans itself up, deallocates
+memory and potentially deletes stuff from disk:
+
+ (7) State FSCACHE_OBJECT_LC_DYING.
+
+     The object comes here if it is dying because of a lookup or creation
+     error.  This would be due to a disk error or system error of some sort.
+     Temporary data is cleaned up, and the parent is released.
+
+ (8) State FSCACHE_OBJECT_DYING.
+
+     The object comes here if it is dying due to an error, because its parent
+     cookie has been relinquished by the netfs or because the cache is being
+     withdrawn.
+
+     Any child objects waiting on this one are given CPU time so that they too
+     can destroy themselves.  This object waits for all its children to go away
+     before advancing to the next state.
+
+ (9) State FSCACHE_OBJECT_ABORT_INIT.
+
+     The object comes to this state if it was waiting on its parent in
+     FSCACHE_OBJECT_INIT, but its parent died.  The object will destroy itself
+     so that the parent may proceed from the FSCACHE_OBJECT_DYING state.
+
+(10) State FSCACHE_OBJECT_RELEASING.
+(11) State FSCACHE_OBJECT_RECYCLING.
+
+     The object comes to one of these two states when dying once it is rid of
+     all its children, if it is dying because the netfs relinquished its
+     cookie.  In the first state, the cached data is expected to persist, and
+     in the second it will be deleted.
+
+(12) State FSCACHE_OBJECT_WITHDRAWING.
+
+     The object transits to this state if the cache decides it wants to
+     withdraw the object from service, perhaps to make space, but also due to
+     error or just because the whole cache is being withdrawn.
+
+(13) State FSCACHE_OBJECT_DEAD.
+
+     The object transits to this state when the in-memory object record is
+     ready to be deleted.  The object processor shouldn't ever see an object in
+     this state.
+
+
+THE SET OF EVENTS
+-----------------
+
+There are a number of events that can be raised to an object state machine:
+
+ (*) FSCACHE_OBJECT_EV_UPDATE
+
+     The netfs requested that an object be updated.  The state machine will ask
+     the cache backend to update the object, and the cache backend will ask the
+     netfs for details of the change through its cookie definition ops.
+
+ (*) FSCACHE_OBJECT_EV_CLEARED
+
+     This is signalled in two circumstances:
+
+     (a) when an object's last child object is dropped and
+
+     (b) when the last operation outstanding on an object is completed.
+
+     This is used to proceed from the dying state.
+
+ (*) FSCACHE_OBJECT_EV_ERROR
+
+     This is signalled when an I/O error occurs during the processing of some
+     object.
+
+ (*) FSCACHE_OBJECT_EV_RELEASE
+ (*) FSCACHE_OBJECT_EV_RETIRE
+
+     These are signalled when the netfs relinquishes a cookie it was using.
+     The event selected depends on whether the netfs asks for the backing
+     object to be retired (deleted) or retained.
+
+ (*) FSCACHE_OBJECT_EV_WITHDRAW
+
+     This is signalled when the cache backend wants to withdraw an object.
+     This means that the object will have to be detached from the netfs's
+     cookie.
+
+Because the withdrawing releasing/retiring events are all handled by the object
+state machine, it doesn't matter if there's a collision with both ends trying
+to sever the connection at the same time.  The state machine can just pick
+which one it wants to honour, and that effects the other.

Documentation/filesystems/caching/operations.txt

@@ -0,0 +1,213 @@
+		       ================================
+		       ASYNCHRONOUS OPERATIONS HANDLING
+		       ================================
+
+By: David Howells <dhowells@redhat.com>
+
+Contents:
+
+ (*) Overview.
+
+ (*) Operation record initialisation.
+
+ (*) Parameters.
+
+ (*) Procedure.
+
+ (*) Asynchronous callback.
+
+
+========
+OVERVIEW
+========
+
+FS-Cache has an asynchronous operations handling facility that it uses for its
+data storage and retrieval routines.  Its operations are represented by
+fscache_operation structs, though these are usually embedded into some other
+structure.
+
+This facility is available to and expected to be be used by the cache backends,
+and FS-Cache will create operations and pass them off to the appropriate cache
+backend for completion.
+
+To make use of this facility, <linux/fscache-cache.h> should be #included.
+
+
+===============================
+OPERATION RECORD INITIALISATION
+===============================
+
+An operation is recorded in an fscache_operation struct:
+
+	struct fscache_operation {
+		union {
+			struct work_struct fast_work;
+			struct slow_work slow_work;
+		};
+		unsigned long		flags;
+		fscache_operation_processor_t processor;
+		...
+	};
+
+Someone wanting to issue an operation should allocate something with this
+struct embedded in it.  They should initialise it by calling:
+
+	void fscache_operation_init(struct fscache_operation *op,
+				    fscache_operation_release_t release);
+
+with the operation to be initialised and the release function to use.
+
+The op->flags parameter should be set to indicate the CPU time provision and
+the exclusivity (see the Parameters section).
+
+The op->fast_work, op->slow_work and op->processor flags should be set as
+appropriate for the CPU time provision (see the Parameters section).
+
+FSCACHE_OP_WAITING may be set in op->flags prior to each submission of the
+operation and waited for afterwards.
+
+
+==========
+PARAMETERS
+==========
+
+There are a number of parameters that can be set in the operation record's flag
+parameter.  There are three options for the provision of CPU time in these
+operations:
+
+ (1) The operation may be done synchronously (FSCACHE_OP_MYTHREAD).  A thread
+     may decide it wants to handle an operation itself without deferring it to
+     another thread.
+
+     This is, for example, used in read operations for calling readpages() on
+     the backing filesystem in CacheFiles.  Although readpages() does an
+     asynchronous data fetch, the determination of whether pages exist is done
+     synchronously - and the netfs does not proceed until this has been
+     determined.
+
+     If this option is to be used, FSCACHE_OP_WAITING must be set in op->flags
+     before submitting the operation, and the operating thread must wait for it
+     to be cleared before proceeding:
+
+		wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
+			    fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+
+
+ (2) The operation may be fast asynchronous (FSCACHE_OP_FAST), in which case it
+     will be given to keventd to process.  Such an operation is not permitted
+     to sleep on I/O.
+
+     This is, for example, used by CacheFiles to copy data from a backing fs
+     page to a netfs page after the backing fs has read the page in.
+
+     If this option is used, op->fast_work and op->processor must be
+     initialised before submitting the operation:
+
+		INIT_WORK(&op->fast_work, do_some_work);
+
+
+ (3) The operation may be slow asynchronous (FSCACHE_OP_SLOW), in which case it
+     will be given to the slow work facility to process.  Such an operation is
+     permitted to sleep on I/O.
+
+     This is, for example, used by FS-Cache to handle background writes of
+     pages that have just been fetched from a remote server.
+
+     If this option is used, op->slow_work and op->processor must be
+     initialised before submitting the operation:
+
+		fscache_operation_init_slow(op, processor)
+
+
+Furthermore, operations may be one of two types:
+
+ (1) Exclusive (FSCACHE_OP_EXCLUSIVE).  Operations of this type may not run in
+     conjunction with any other operation on the object being operated upon.
+
+     An example of this is the attribute change operation, in which the file
+     being written to may need truncation.
+
+ (2) Shareable.  Operations of this type may be running simultaneously.  It's
+     up to the operation implementation to prevent interference between other
+     operations running at the same time.
+
+
+=========
+PROCEDURE
+=========
+
+Operations are used through the following procedure:
+
+ (1) The submitting thread must allocate the operation and initialise it
+     itself.  Normally this would be part of a more specific structure with the
+     generic op embedded within.
+
+ (2) The submitting thread must then submit the operation for processing using
+     one of the following two functions:
+
+	int fscache_submit_op(struct fscache_object *object,
+			      struct fscache_operation *op);
+
+	int fscache_submit_exclusive_op(struct fscache_object *object,
+					struct fscache_operation *op);
+
+     The first function should be used to submit non-exclusive ops and the
+     second to submit exclusive ones.  The caller must still set the
+     FSCACHE_OP_EXCLUSIVE flag.
+
+     If successful, both functions will assign the operation to the specified
+     object and return 0.  -ENOBUFS will be returned if the object specified is
+     permanently unavailable.
+
+     The operation manager will defer operations on an object that is still
+     undergoing lookup or creation.  The operation will also be deferred if an
+     operation of conflicting exclusivity is in progress on the object.
+
+     If the operation is asynchronous, the manager will retain a reference to
+     it, so the caller should put their reference to it by passing it to:
+
+	void fscache_put_operation(struct fscache_operation *op);
+
+ (3) If the submitting thread wants to do the work itself, and has marked the
+     operation with FSCACHE_OP_MYTHREAD, then it should monitor
+     FSCACHE_OP_WAITING as described above and check the state of the object if
+     necessary (the object might have died whilst the thread was waiting).
+
+     When it has finished doing its processing, it should call
+     fscache_put_operation() on it.
+
+ (4) The operation holds an effective lock upon the object, preventing other
+     exclusive ops conflicting until it is released.  The operation can be
+     enqueued for further immediate asynchronous processing by adjusting the
+     CPU time provisioning option if necessary, eg:
+
+	op->flags &= ~FSCACHE_OP_TYPE;
+	op->flags |= ~FSCACHE_OP_FAST;
+
+     and calling:
+
+	void fscache_enqueue_operation(struct fscache_operation *op)
+
+     This can be used to allow other things to have use of the worker thread
+     pools.
+
+
+=====================
+ASYNCHRONOUS CALLBACK
+=====================
+
+When used in asynchronous mode, the worker thread pool will invoke the
+processor method with a pointer to the operation.  This should then get at the
+container struct by using container_of():
+
+	static void fscache_write_op(struct fscache_operation *_op)
+	{
+		struct fscache_storage *op =
+			container_of(_op, struct fscache_storage, op);
+	...
+	}
+
+The caller holds a reference on the operation, and will invoke
+fscache_put_operation() when the processor function returns.  The processor
+function is at liberty to call fscache_enqueue_operation() or to take extra
+references.

Documentation/filesystems/exofs.txt

@@ -0,0 +1,176 @@
+===============================================================================
+WHAT IS EXOFS?
+===============================================================================
+
+exofs is a file system that uses an OSD and exports the API of a normal Linux
+file system. Users access exofs like any other local file system, and exofs
+will in turn issue commands to the local OSD initiator.
+
+OSD is a new T10 command set that views storage devices not as a large/flat
+array of sectors but as a container of objects, each having a length, quota,
+time attributes and more. Each object is addressed by a 64bit ID, and is
+contained in a 64bit ID partition. Each object has associated attributes
+attached to it, which are integral part of the object and provide metadata about
+the object. The standard defines some common obligatory attributes, but user
+attributes can be added as needed.
+
+===============================================================================
+ENVIRONMENT
+===============================================================================
+
+To use this file system, you need to have an object store to run it on.  You
+may download a target from:
+http://open-osd.org
+
+See Documentation/scsi/osd.txt for how to setup a working osd environment.
+
+===============================================================================
+USAGE
+===============================================================================
+
+1. Download and compile exofs and open-osd initiator:
+  You need an external Kernel source tree or kernel headers from your
+  distribution. (anything based on 2.6.26 or later).
+
+  a. download open-osd including exofs source using:
+     [parent-directory]$ git clone git://git.open-osd.org/open-osd.git
+
+  b. Build the library module like this:
+     [parent-directory]$ make -C KSRC=$(KER_DIR) open-osd
+
+     This will build both the open-osd initiator as well as the exofs kernel
+     module. Use whatever parameters you compiled your Kernel with and
+     $(KER_DIR) above pointing to the Kernel you compile against. See the file
+     open-osd/top-level-Makefile for an example.
+
+2. Get the OSD initiator and target set up properly, and login to the target.
+  See Documentation/scsi/osd.txt for farther instructions. Also see ./do-osd
+  for example script that does all these steps.
+
+3. Insmod the exofs.ko module:
+   [exofs]$ insmod exofs.ko
+
+4. Make sure the directory where you want to mount exists. If not, create it.
+   (For example, mkdir /mnt/exofs)
+
+5. At first run you will need to invoke the mkfs.exofs application
+
+   As an example, this will create the file system on:
+   /dev/osd0 partition ID 65536
+
+   mkfs.exofs --pid=65536 --format /dev/osd0
+
+   The --format is optional if not specified no OSD_FORMAT will be
+   preformed and a clean file system will be created in the specified pid,
+   in the available space of the target. (Use --format=size_in_meg to limit
+   the total LUN space available)
+
+   If pid already exist it will be deleted and a new one will be created in it's
+   place. Be careful.
+
+   An exofs lives inside a single OSD partition. You can create multiple exofs
+   filesystems on the same device using multiple pids.
+
+   (run mkfs.exofs without any parameters for usage help message)
+
+6. Mount the file system.
+
+   For example, to mount /dev/osd0, partition ID 0x10000 on /mnt/exofs:
+
+	mount -t exofs -o pid=65536 /dev/osd0 /mnt/exofs/
+
+7. For reference (See do-exofs example script):
+	do-exofs start - an example of how to perform the above steps.
+	do-exofs stop -  an example of how to unmount the file system.
+	do-exofs format - an example of how to format and mkfs a new exofs.
+
+8. Extra compilation flags (uncomment in fs/exofs/Kbuild):
+	CONFIG_EXOFS_DEBUG - for debug messages and extra checks.
+
+===============================================================================
+exofs mount options
+===============================================================================
+Similar to any mount command:
+	mount -t exofs -o exofs_options /dev/osdX mount_exofs_directory
+
+Where:
+    -t exofs: specifies the exofs file system
+
+    /dev/osdX: X is a decimal number. /dev/osdX was created after a successful
+               login into an OSD target.
+
+    mount_exofs_directory: The directory to mount the file system on
+
+    exofs specific options: Options are separated by commas (,)
+		pid=<integer> - The partition number to mount/create as
+                                container of the filesystem.
+                                This option is mandatory
+                to=<integer>  - Timeout in ticks for a single command
+                                default is (60 * HZ) [for debugging only]
+
+===============================================================================
+DESIGN
+===============================================================================
+
+* The file system control block (AKA on-disk superblock) resides in an object
+  with a special ID (defined in common.h).
+  Information included in the file system control block is used to fill the
+  in-memory superblock structure at mount time. This object is created before
+  the file system is used by mkexofs.c It contains information such as:
+	- The file system's magic number
+	- The next inode number to be allocated
+
+* Each file resides in its own object and contains the data (and it will be
+  possible to extend the file over multiple objects, though this has not been
+  implemented yet).
+
+* A directory is treated as a file, and essentially contains a list of <file
+  name, inode #> pairs for files that are found in that directory. The object
+  IDs correspond to the files' inode numbers and will be allocated according to
+  a bitmap (stored in a separate object). Now they are allocated using a
+  counter.
+
+* Each file's control block (AKA on-disk inode) is stored in its object's
+  attributes. This applies to both regular files and other types (directories,
+  device files, symlinks, etc.).
+
+* Credentials are generated per object (inode and superblock) when they is
+  created in memory (read off disk or created). The credential works for all
+  operations and is used as long as the object remains in memory.
+
+* Async OSD operations are used whenever possible, but the target may execute
+  them out of order. The operations that concern us are create, delete,
+  readpage, writepage, update_inode, and truncate. The following pairs of
+  operations should execute in the order written, and we need to prevent them
+  from executing in reverse order:
+	- The following are handled with the OBJ_CREATED and OBJ_2BCREATED
+	  flags. OBJ_CREATED is set when we know the object exists on the OSD -
+	  in create's callback function, and when we successfully do a read_inode.
+	  OBJ_2BCREATED is set in the beginning of the create function, so we
+	  know that we should wait.
+		- create/delete: delete should wait until the object is created
+		  on the OSD.
+		- create/readpage: readpage should be able to return a page
+		  full of zeroes in this case. If there was a write already
+		  en-route (i.e. create, writepage, readpage) then the page
+		  would be locked, and so it would really be the same as
+		  create/writepage.
+		- create/writepage: if writepage is called for a sync write, it
+		  should wait until the object is created on the OSD.
+		  Otherwise, it should just return.
+		- create/truncate: truncate should wait until the object is
+		  created on the OSD.
+		- create/update_inode: update_inode should wait until the
+		  object is created on the OSD.
+	- Handled by VFS locks:
+		- readpage/delete: shouldn't happen because of page lock.
+		- writepage/delete: shouldn't happen because of page lock.
+		- readpage/writepage: shouldn't happen because of page lock.
+
+===============================================================================
+LICENSE/COPYRIGHT
+===============================================================================
+The exofs file system is based on ext2 v0.5b (distributed with the Linux kernel
+version 2.6.10).  All files include the original copyrights, and the license
+is GPL version 2 (only version 2, as is true for the Linux kernel).  The
+Linux kernel can be downloaded from www.kernel.org.

Documentation/filesystems/ext3.txt

@@ -14,6 +14,11 @@ Options
 When mounting an ext3 filesystem, the following option are accepted:
 (*) == default
 
+ro			Mount filesystem read only. Note that ext3 will replay
+			the journal (and thus write to the partition) even when
+			mounted "read only". Mount options "ro,noload" can be
+			used to prevent writes to the filesystem.
+
 journal=update		Update the ext3 file system's journal to the current
 			format.
 
@@ -27,7 +32,9 @@ journal_dev=devnum	When the external journal device's major/minor numbers
 			identified through its new major/minor numbers encoded
 			in devnum.
 
-noload			Don't load the journal on mounting.
+noload			Don't load the journal on mounting. Note that this forces
+			mount of inconsistent filesystem, which can lead to
+			various problems.
 
 data=journal		All data are committed into the journal prior to being
 			written into the main file system.
@@ -92,9 +99,12 @@ nocheck
 
 debug			Extra debugging information is sent to syslog.
 
-errors=remount-ro(*)	Remount the filesystem read-only on an error.
+errors=remount-ro	Remount the filesystem read-only on an error.
 errors=continue		Keep going on a filesystem error.
 errors=panic		Panic and halt the machine if an error occurs.
+			(These mount options override the errors behavior
+			specified in the superblock, which can be
+			configured using tune2fs.)
 
 data_err=ignore(*)	Just print an error message if an error occurs
 			in a file data buffer in ordered mode.

Documentation/filesystems/ext4.txt

@@ -85,7 +85,7 @@ Note: More extensive information for getting started with ext4 can be
 * extent format more robust in face of on-disk corruption due to magics,
 * internal redundancy in tree
 * improved file allocation (multi-block alloc)
-* fix 32000 subdirectory limit
+* lift 32000 subdirectory limit imposed by i_links_count[1]
 * nsec timestamps for mtime, atime, ctime, create time
 * inode version field on disk (NFSv4, Lustre)
 * reduced e2fsck time via uninit_bg feature
@@ -100,6 +100,9 @@ Note: More extensive information for getting started with ext4 can be
 * efficent new ordered mode in JBD2 and ext4(avoid using buffer head to force
   the ordering)
 
+[1] Filesystems with a block size of 1k may see a limit imposed by the
+directory hash tree having a maximum depth of two.
+
 2.2 Candidate features for future inclusion
 
 * Online defrag (patches available but not well tested)
@@ -180,8 +183,8 @@ commit=nrsec	(*)	Ext4 can be told to sync all its data and metadata
 			performance.
 
 barrier=<0|1(*)>	This enables/disables the use of write barriers in
-			the jbd code.  barrier=0 disables, barrier=1 enables.
-			This also requires an IO stack which can support
+barrier(*)		the jbd code.  barrier=0 disables, barrier=1 enables.
+nobarrier		This also requires an IO stack which can support
 			barriers, and if jbd gets an error on a barrier
 			write, it will disable again with a warning.
 			Write barriers enforce proper on-disk ordering
@@ -189,6 +192,9 @@ barrier=<0|1(*)>	This enables/disables the use of write barriers in
 			safe to use, at some performance penalty.  If
 			your disks are battery-backed in one way or another,
 			disabling barriers may safely improve performance.
+			The mount options "barrier" and "nobarrier" can
+			also be used to enable or disable barriers, for
+			consistency with other ext4 mount options.
 
 inode_readahead=n	This tuning parameter controls the maximum
 			number of inode table blocks that ext4's inode
@@ -310,6 +316,24 @@ journal_ioprio=prio	The I/O priority (from 0 to 7, where 0 is the
 			a slightly higher priority than the default I/O
 			priority.
 
+auto_da_alloc(*)	Many broken applications don't use fsync() when 
+noauto_da_alloc		replacing existing files via patterns such as
+			fd = open("foo.new")/write(fd,..)/close(fd)/
+			rename("foo.new", "foo"), or worse yet,
+			fd = open("foo", O_TRUNC)/write(fd,..)/close(fd).
+			If auto_da_alloc is enabled, ext4 will detect
+			the replace-via-rename and replace-via-truncate
+			patterns and force that any delayed allocation
+			blocks are allocated such that at the next
+			journal commit, in the default data=ordered
+			mode, the data blocks of the new file are forced
+			to disk before the rename() operation is
+			commited.  This provides roughly the same level
+			of guarantees as ext3, and avoids the
+			"zero-length" problem that can happen when a
+			system crashes before the delayed allocation
+			blocks are forced to disk.
+
 Data Mode
 =========
 There are 3 different data modes:

Documentation/filesystems/knfsd-stats.txt

@@ -0,0 +1,159 @@
+
+Kernel NFS Server Statistics
+============================
+
+This document describes the format and semantics of the statistics
+which the kernel NFS server makes available to userspace.  These
+statistics are available in several text form pseudo files, each of
+which is described separately below.
+
+In most cases you don't need to know these formats, as the nfsstat(8)
+program from the nfs-utils distribution provides a helpful command-line
+interface for extracting and printing them.
+
+All the files described here are formatted as a sequence of text lines,
+separated by newline '\n' characters.  Lines beginning with a hash
+'#' character are comments intended for humans and should be ignored
+by parsing routines.  All other lines contain a sequence of fields
+separated by whitespace.
+
+/proc/fs/nfsd/pool_stats
+------------------------
+
+This file is available in kernels from 2.6.30 onwards, if the
+/proc/fs/nfsd filesystem is mounted (it almost always should be).
+
+The first line is a comment which describes the fields present in
+all the other lines.  The other lines present the following data as
+a sequence of unsigned decimal numeric fields.  One line is shown
+for each NFS thread pool.
+
+All counters are 64 bits wide and wrap naturally.  There is no way
+to zero these counters, instead applications should do their own
+rate conversion.
+
+pool
+	The id number of the NFS thread pool to which this line applies.
+	This number does not change.
+
+	Thread pool ids are a contiguous set of small integers starting
+	at zero.  The maximum value depends on the thread pool mode, but
+	currently cannot be larger than the number of CPUs in the system.
+	Note that in the default case there will be a single thread pool
+	which contains all the nfsd threads and all the CPUs in the system,
+	and thus this file will have a single line with a pool id of "0".
+
+packets-arrived
+	Counts how many NFS packets have arrived.  More precisely, this
+	is the number of times that the network stack has notified the
+	sunrpc server layer that new data may be available on a transport
+	(e.g. an NFS or UDP socket or an NFS/RDMA endpoint).
+
+	Depending on the NFS workload patterns and various network stack
+	effects (such as Large Receive Offload) which can combine packets
+	on the wire, this may be either more or less than the number
+	of NFS calls received (which statistic is available elsewhere).
+	However this is a more accurate and less workload-dependent measure
+	of how much CPU load is being placed on the sunrpc server layer
+	due to NFS network traffic.
+
+sockets-enqueued
+	Counts how many times an NFS transport is enqueued to wait for
+	an nfsd thread to service it, i.e. no nfsd thread was considered
+	available.
+
+	The circumstance this statistic tracks indicates that there was NFS
+	network-facing work to be done but it couldn't be done immediately,
+	thus introducing a small delay in servicing NFS calls.  The ideal
+	rate of change for this counter is zero; significantly non-zero
+	values may indicate a performance limitation.
+
+	This can happen either because there are too few nfsd threads in the
+	thread pool for the NFS workload (the workload is thread-limited),
+	or because the NFS workload needs more CPU time than is available in
+	the thread pool (the workload is CPU-limited).  In the former case,
+	configuring more nfsd threads will probably improve the performance
+	of the NFS workload.  In the latter case, the sunrpc server layer is
+	already choosing not to wake idle nfsd threads because there are too
+	many nfsd threads which want to run but cannot, so configuring more
+	nfsd threads will make no difference whatsoever.  The overloads-avoided
+	statistic (see below) can be used to distinguish these cases.
+
+threads-woken
+	Counts how many times an idle nfsd thread is woken to try to
+	receive some data from an NFS transport.
+
+	This statistic tracks the circumstance where incoming
+	network-facing NFS work is being handled quickly, which is a good
+	thing.  The ideal rate of change for this counter will be close
+	to but less than the rate of change of the packets-arrived counter.
+
+overloads-avoided
+	Counts how many times the sunrpc server layer chose not to wake an
+	nfsd thread, despite the presence of idle nfsd threads, because
+	too many nfsd threads had been recently woken but could not get
+	enough CPU time to actually run.
+
+	This statistic counts a circumstance where the sunrpc layer
+	heuristically avoids overloading the CPU scheduler with too many
+	runnable nfsd threads.  The ideal rate of change for this counter
+	is zero.  Significant non-zero values indicate that the workload
+	is CPU limited.  Usually this is associated with heavy CPU usage
+	on all the CPUs in the nfsd thread pool.
+
+	If a sustained large overloads-avoided rate is detected on a pool,
+	the top(1) utility should be used to check for the following
+	pattern of CPU usage on all the CPUs associated with the given
+	nfsd thread pool.
+
+	 - %us ~= 0 (as you're *NOT* running applications on your NFS server)
+
+	 - %wa ~= 0
+
+	 - %id ~= 0
+
+	 - %sy + %hi + %si ~= 100
+
+	If this pattern is seen, configuring more nfsd threads will *not*
+	improve the performance of the workload.  If this patten is not
+	seen, then something more subtle is wrong.
+
+threads-timedout
+	Counts how many times an nfsd thread triggered an idle timeout,
+	i.e. was not woken to handle any incoming network packets for
+	some time.
+
+	This statistic counts a circumstance where there are more nfsd
+	threads configured than can be used by the NFS workload.  This is
+	a clue that the number of nfsd threads can be reduced without
+	affecting performance.  Unfortunately, it's only a clue and not
+	a strong indication, for a couple of reasons:
+
+	 - Currently the rate at which the counter is incremented is quite
+	   slow; the idle timeout is 60 minutes.  Unless the NFS workload
+	   remains constant for hours at a time, this counter is unlikely
+	   to be providing information that is still useful.
+
+	 - It is usually a wise policy to provide some slack,
+	   i.e. configure a few more nfsds than are currently needed,
+	   to allow for future spikes in load.
+
+
+Note that incoming packets on NFS transports will be dealt with in
+one of three ways.  An nfsd thread can be woken (threads-woken counts
+this case), or the transport can be enqueued for later attention
+(sockets-enqueued counts this case), or the packet can be temporarily
+deferred because the transport is currently being used by an nfsd
+thread.  This last case is not very interesting and is not explicitly
+counted, but can be inferred from the other counters thus:
+
+packets-deferred = packets-arrived - ( sockets-enqueued + threads-woken )
+
+
+More
+----
+Descriptions of the other statistics file should go here.
+
+
+Greg Banks <gnb@sgi.com>
+26 Mar 2009

Documentation/filesystems/nfs41-server.txt

@@ -0,0 +1,161 @@
+NFSv4.1 Server Implementation
+
+Server support for minorversion 1 can be controlled using the
+/proc/fs/nfsd/versions control file.  The string output returned
+by reading this file will contain either "+4.1" or "-4.1"
+correspondingly.
+
+Currently, server support for minorversion 1 is disabled by default.
+It can be enabled at run time by writing the string "+4.1" to
+the /proc/fs/nfsd/versions control file.  Note that to write this
+control file, the nfsd service must be taken down.  Use your user-mode
+nfs-utils to set this up; see rpc.nfsd(8)
+
+The NFSv4 minorversion 1 (NFSv4.1) implementation in nfsd is based
+on the latest NFSv4.1 Internet Draft:
+http://tools.ietf.org/html/draft-ietf-nfsv4-minorversion1-29
+
+From the many new features in NFSv4.1 the current implementation
+focuses on the mandatory-to-implement NFSv4.1 Sessions, providing
+"exactly once" semantics and better control and throttling of the
+resources allocated for each client.
+
+Other NFSv4.1 features, Parallel NFS operations in particular,
+are still under development out of tree.
+See http://wiki.linux-nfs.org/wiki/index.php/PNFS_prototype_design
+for more information.
+
+The table below, taken from the NFSv4.1 document, lists
+the operations that are mandatory to implement (REQ), optional
+(OPT), and NFSv4.0 operations that are required not to implement (MNI)
+in minor version 1.  The first column indicates the operations that
+are not supported yet by the linux server implementation.
+
+The OPTIONAL features identified and their abbreviations are as follows:
+	pNFS	Parallel NFS
+	FDELG	File Delegations
+	DDELG	Directory Delegations
+
+The following abbreviations indicate the linux server implementation status.
+	I	Implemented NFSv4.1 operations.
+	NS	Not Supported.
+	NS*	unimplemented optional feature.
+	P	pNFS features implemented out of tree.
+	PNS	pNFS features that are not supported yet (out of tree).
+
+Operations
+
+   +----------------------+------------+--------------+----------------+
+   | Operation            | REQ, REC,  | Feature      | Definition     |
+   |                      | OPT, or    | (REQ, REC,   |                |
+   |                      | MNI        | or OPT)      |                |
+   +----------------------+------------+--------------+----------------+
+   | ACCESS               | REQ        |              | Section 18.1   |
+NS | BACKCHANNEL_CTL      | REQ        |              | Section 18.33  |
+NS | BIND_CONN_TO_SESSION | REQ        |              | Section 18.34  |
+   | CLOSE                | REQ        |              | Section 18.2   |
+   | COMMIT               | REQ        |              | Section 18.3   |
+   | CREATE               | REQ        |              | Section 18.4   |
+I  | CREATE_SESSION       | REQ        |              | Section 18.36  |
+NS*| DELEGPURGE           | OPT        | FDELG (REQ)  | Section 18.5   |
+   | DELEGRETURN          | OPT        | FDELG,       | Section 18.6   |
+   |                      |            | DDELG, pNFS  |                |
+   |                      |            | (REQ)        |                |
+NS | DESTROY_CLIENTID     | REQ        |              | Section 18.50  |
+I  | DESTROY_SESSION      | REQ        |              | Section 18.37  |
+I  | EXCHANGE_ID          | REQ        |              | Section 18.35  |
+NS | FREE_STATEID         | REQ        |              | Section 18.38  |
+   | GETATTR              | REQ        |              | Section 18.7   |
+P  | GETDEVICEINFO        | OPT        | pNFS (REQ)   | Section 18.40  |
+P  | GETDEVICELIST        | OPT        | pNFS (OPT)   | Section 18.41  |
+   | GETFH                | REQ        |              | Section 18.8   |
+NS*| GET_DIR_DELEGATION   | OPT        | DDELG (REQ)  | Section 18.39  |
+P  | LAYOUTCOMMIT         | OPT        | pNFS (REQ)   | Section 18.42  |
+P  | LAYOUTGET            | OPT        | pNFS (REQ)   | Section 18.43  |
+P  | LAYOUTRETURN         | OPT        | pNFS (REQ)   | Section 18.44  |
+   | LINK                 | OPT        |              | Section 18.9   |
+   | LOCK                 | REQ        |              | Section 18.10  |
+   | LOCKT                | REQ        |              | Section 18.11  |
+   | LOCKU                | REQ        |              | Section 18.12  |
+   | LOOKUP               | REQ        |              | Section 18.13  |
+   | LOOKUPP              | REQ        |              | Section 18.14  |
+   | NVERIFY              | REQ        |              | Section 18.15  |
+   | OPEN                 | REQ        |              | Section 18.16  |
+NS*| OPENATTR             | OPT        |              | Section 18.17  |
+   | OPEN_CONFIRM         | MNI        |              | N/A            |
+   | OPEN_DOWNGRADE       | REQ        |              | Section 18.18  |
+   | PUTFH                | REQ        |              | Section 18.19  |
+   | PUTPUBFH             | REQ        |              | Section 18.20  |
+   | PUTROOTFH            | REQ        |              | Section 18.21  |
+   | READ                 | REQ        |              | Section 18.22  |
+   | READDIR              | REQ        |              | Section 18.23  |
+   | READLINK             | OPT        |              | Section 18.24  |
+NS | RECLAIM_COMPLETE     | REQ        |              | Section 18.51  |
+   | RELEASE_LOCKOWNER    | MNI        |              | N/A            |
+   | REMOVE               | REQ        |              | Section 18.25  |
+   | RENAME               | REQ        |              | Section 18.26  |
+   | RENEW                | MNI        |              | N/A            |
+   | RESTOREFH            | REQ        |              | Section 18.27  |
+   | SAVEFH               | REQ        |              | Section 18.28  |
+   | SECINFO              | REQ        |              | Section 18.29  |
+NS | SECINFO_NO_NAME      | REC        | pNFS files   | Section 18.45, |
+   |                      |            | layout (REQ) | Section 13.12  |
+I  | SEQUENCE             | REQ        |              | Section 18.46  |
+   | SETATTR              | REQ        |              | Section 18.30  |
+   | SETCLIENTID          | MNI        |              | N/A            |
+   | SETCLIENTID_CONFIRM  | MNI        |              | N/A            |
+NS | SET_SSV              | REQ        |              | Section 18.47  |
+NS | TEST_STATEID         | REQ        |              | Section 18.48  |
+   | VERIFY               | REQ        |              | Section 18.31  |
+NS*| WANT_DELEGATION      | OPT        | FDELG (OPT)  | Section 18.49  |
+   | WRITE                | REQ        |              | Section 18.32  |
+
+Callback Operations
+
+   +-------------------------+-----------+-------------+---------------+
+   | Operation               | REQ, REC, | Feature     | Definition    |
+   |                         | OPT, or   | (REQ, REC,  |               |
+   |                         | MNI       | or OPT)     |               |
+   +-------------------------+-----------+-------------+---------------+
+   | CB_GETATTR              | OPT       | FDELG (REQ) | Section 20.1  |
+P  | CB_LAYOUTRECALL         | OPT       | pNFS (REQ)  | Section 20.3  |
+NS*| CB_NOTIFY               | OPT       | DDELG (REQ) | Section 20.4  |
+P  | CB_NOTIFY_DEVICEID      | OPT       | pNFS (OPT)  | Section 20.12 |
+NS*| CB_NOTIFY_LOCK          | OPT       |             | Section 20.11 |
+NS*| CB_PUSH_DELEG           | OPT       | FDELG (OPT) | Section 20.5  |
+   | CB_RECALL               | OPT       | FDELG,      | Section 20.2  |
+   |                         |           | DDELG, pNFS |               |
+   |                         |           | (REQ)       |               |
+NS*| CB_RECALL_ANY           | OPT       | FDELG,      | Section 20.6  |
+   |                         |           | DDELG, pNFS |               |
+   |                         |           | (REQ)       |               |
+NS | CB_RECALL_SLOT          | REQ       |             | Section 20.8  |
+NS*| CB_RECALLABLE_OBJ_AVAIL | OPT       | DDELG, pNFS | Section 20.7  |
+   |                         |           | (REQ)       |               |
+I  | CB_SEQUENCE             | OPT       | FDELG,      | Section 20.9  |
+   |                         |           | DDELG, pNFS |               |
+   |                         |           | (REQ)       |               |
+NS*| CB_WANTS_CANCELLED      | OPT       | FDELG,      | Section 20.10 |
+   |                         |           | DDELG, pNFS |               |
+   |                         |           | (REQ)       |               |
+   +-------------------------+-----------+-------------+---------------+
+
+Implementation notes:
+
+EXCHANGE_ID:
+* only SP4_NONE state protection supported
+* implementation ids are ignored
+
+CREATE_SESSION:
+* backchannel attributes are ignored
+* backchannel security parameters are ignored
+
+SEQUENCE:
+* no support for dynamic slot table renegotiation (optional)
+
+nfsv4.1 COMPOUND rules:
+The following cases aren't supported yet:
+* Enforcing of NFS4ERR_NOT_ONLY_OP for: BIND_CONN_TO_SESSION, CREATE_SESSION,
+  DESTROY_CLIENTID, DESTROY_SESSION, EXCHANGE_ID.
+* DESTROY_SESSION MUST be the final operation in the COMPOUND request.
+

Documentation/filesystems/nilfs2.txt

@@ -0,0 +1,200 @@
+NILFS2
+------
+
+NILFS2 is a log-structured file system (LFS) supporting continuous
+snapshotting.  In addition to versioning capability of the entire file
+system, users can even restore files mistakenly overwritten or
+destroyed just a few seconds ago.  Since NILFS2 can keep consistency
+like conventional LFS, it achieves quick recovery after system
+crashes.
+
+NILFS2 creates a number of checkpoints every few seconds or per
+synchronous write basis (unless there is no change).  Users can select
+significant versions among continuously created checkpoints, and can
+change them into snapshots which will be preserved until they are
+changed back to checkpoints.
+
+There is no limit on the number of snapshots until the volume gets
+full.  Each snapshot is mountable as a read-only file system
+concurrently with its writable mount, and this feature is convenient
+for online backup.
+
+The userland tools are included in nilfs-utils package, which is
+available from the following download page.  At least "mkfs.nilfs2",
+"mount.nilfs2", "umount.nilfs2", and "nilfs_cleanerd" (so called
+cleaner or garbage collector) are required.  Details on the tools are
+described in the man pages included in the package.
+
+Project web page:    http://www.nilfs.org/en/
+Download page:       http://www.nilfs.org/en/download.html
+Git tree web page:   http://www.nilfs.org/git/
+NILFS mailing lists: http://www.nilfs.org/mailman/listinfo/users
+
+Caveats
+=======
+
+Features which NILFS2 does not support yet:
+
+	- atime
+	- extended attributes
+	- POSIX ACLs
+	- quotas
+	- writable snapshots
+	- remote backup (CDP)
+	- data integrity
+	- defragmentation
+
+Mount options
+=============
+
+NILFS2 supports the following mount options:
+(*) == default
+
+barrier=on(*)		This enables/disables barriers. barrier=off disables
+			it, barrier=on enables it.
+errors=continue(*)	Keep going on a filesystem error.
+errors=remount-ro	Remount the filesystem read-only on an error.
+errors=panic		Panic and halt the machine if an error occurs.
+cp=n			Specify the checkpoint-number of the snapshot to be
+			mounted.  Checkpoints and snapshots are listed by lscp
+			user command.  Only the checkpoints marked as snapshot
+			are mountable with this option.  Snapshot is read-only,
+			so a read-only mount option must be specified together.
+order=relaxed(*)	Apply relaxed order semantics that allows modified data
+			blocks to be written to disk without making a
+			checkpoint if no metadata update is going.  This mode
+			is equivalent to the ordered data mode of the ext3
+			filesystem except for the updates on data blocks still
+			conserve atomicity.  This will improve synchronous
+			write performance for overwriting.
+order=strict		Apply strict in-order semantics that preserves sequence
+			of all file operations including overwriting of data
+			blocks.  That means, it is guaranteed that no
+			overtaking of events occurs in the recovered file
+			system after a crash.
+
+NILFS2 usage
+============
+
+To use nilfs2 as a local file system, simply:
+
+ # mkfs -t nilfs2 /dev/block_device
+ # mount -t nilfs2 /dev/block_device /dir
+
+This will also invoke the cleaner through the mount helper program
+(mount.nilfs2).
+
+Checkpoints and snapshots are managed by the following commands.
+Their manpages are included in the nilfs-utils package above.
+
+  lscp     list checkpoints or snapshots.
+  mkcp     make a checkpoint or a snapshot.
+  chcp     change an existing checkpoint to a snapshot or vice versa.
+  rmcp     invalidate specified checkpoint(s).
+
+To mount a snapshot,
+
+ # mount -t nilfs2 -r -o cp=<cno> /dev/block_device /snap_dir
+
+where <cno> is the checkpoint number of the snapshot.
+
+To unmount the NILFS2 mount point or snapshot, simply:
+
+ # umount /dir
+
+Then, the cleaner daemon is automatically shut down by the umount
+helper program (umount.nilfs2).
+
+Disk format
+===========
+
+A nilfs2 volume is equally divided into a number of segments except
+for the super block (SB) and segment #0.  A segment is the container
+of logs.  Each log is composed of summary information blocks, payload
+blocks, and an optional super root block (SR):
+
+   ______________________________________________________
+  | |SB| | Segment | Segment | Segment | ... | Segment | |
+  |_|__|_|____0____|____1____|____2____|_____|____N____|_|
+  0 +1K +4K       +8M       +16M      +24M  +(8MB x N)
+       .             .            (Typical offsets for 4KB-block)
+    .                  .
+  .______________________.
+  | log | log |... | log |
+  |__1__|__2__|____|__m__|
+        .       .
+      .               .
+    .                       .
+  .______________________________.
+  | Summary | Payload blocks  |SR|
+  |_blocks__|_________________|__|
+
+The payload blocks are organized per file, and each file consists of
+data blocks and B-tree node blocks:
+
+    |<---       File-A        --->|<---       File-B        --->|
+   _______________________________________________________________
+    | Data blocks | B-tree blocks | Data blocks | B-tree blocks | ...
+   _|_____________|_______________|_____________|_______________|_
+
+
+Since only the modified blocks are written in the log, it may have
+files without data blocks or B-tree node blocks.
+
+The organization of the blocks is recorded in the summary information
+blocks, which contains a header structure (nilfs_segment_summary), per
+file structures (nilfs_finfo), and per block structures (nilfs_binfo):
+
+  _________________________________________________________________________
+ | Summary | finfo | binfo | ... | binfo | finfo | binfo | ... | binfo |...
+ |_blocks__|___A___|_(A,1)_|_____|(A,Na)_|___B___|_(B,1)_|_____|(B,Nb)_|___
+
+
+The logs include regular files, directory files, symbolic link files
+and several meta data files.  The mata data files are the files used
+to maintain file system meta data.  The current version of NILFS2 uses
+the following meta data files:
+
+ 1) Inode file (ifile)             -- Stores on-disk inodes
+ 2) Checkpoint file (cpfile)       -- Stores checkpoints
+ 3) Segment usage file (sufile)    -- Stores allocation state of segments
+ 4) Data address translation file  -- Maps virtual block numbers to usual
+    (DAT)                             block numbers.  This file serves to
+                                      make on-disk blocks relocatable.
+
+The following figure shows a typical organization of the logs:
+
+  _________________________________________________________________________
+ | Summary | regular file | file  | ... | ifile | cpfile | sufile | DAT |SR|
+ |_blocks__|_or_directory_|_______|_____|_______|________|________|_____|__|
+
+
+To stride over segment boundaries, this sequence of files may be split
+into multiple logs.  The sequence of logs that should be treated as
+logically one log, is delimited with flags marked in the segment
+summary.  The recovery code of nilfs2 looks this boundary information
+to ensure atomicity of updates.
+
+The super root block is inserted for every checkpoints.  It includes
+three special inodes, inodes for the DAT, cpfile, and sufile.  Inodes
+of regular files, directories, symlinks and other special files, are
+included in the ifile.  The inode of ifile itself is included in the
+corresponding checkpoint entry in the cpfile.  Thus, the hierarchy
+among NILFS2 files can be depicted as follows:
+
+  Super block (SB)
+       |
+       v
+  Super root block (the latest cno=xx)
+       |-- DAT
+       |-- sufile
+       `-- cpfile
+              |-- ifile (cno=c1)
+              |-- ifile (cno=c2) ---- file (ino=i1)
+              :        :          |-- file (ino=i2)
+              `-- ifile (cno=xx)  |-- file (ino=i3)
+                                  :        :
+                                  `-- file (ino=yy)
+                                    ( regular file, directory, or symlink )
+
+For detail on the format of each file, please see include/linux/nilfs2_fs.h.

Documentation/filesystems/pohmelfs/design_notes.txt

@@ -0,0 +1,71 @@
+POHMELFS: Parallel Optimized Host Message Exchange Layered File System.
+
+		Evgeniy Polyakov <zbr@ioremap.net>
+
+Homepage: http://www.ioremap.net/projects/pohmelfs
+
+POHMELFS first began as a network filesystem with coherent local data and
+metadata caches but is now evolving into a parallel distributed filesystem.
+
+Main features of this FS include:
+ * Locally coherent cache for data and metadata with (potentially) byte-range locks.
+	Since all Linux filesystems lock the whole inode during writing, algorithm
+	is very simple and does not use byte-ranges, although they are sent in
+	locking messages.
+ * Completely async processing of all events except creation of hard and symbolic
+	links, and rename events.
+	Object creation and data reading and writing are processed asynchronously.
+ * Flexible object architecture optimized for network processing.
+	Ability to create long paths to objects and remove arbitrarily huge
+	directories with a single network command.
+	(like removing the whole kernel tree via a single network command).
+ * Very high performance.
+ * Fast and scalable multithreaded userspace server. Being in userspace it works
+	with any underlying filesystem and still is much faster than async in-kernel NFS one.
+ * Client is able to switch between different servers (if one goes down, client
+	automatically reconnects to second and so on).
+ * Transactions support. Full failover for all operations.
+	Resending transactions to different servers on timeout or error.
+ * Read request (data read, directory listing, lookup requests) balancing between multiple servers.
+ * Write requests are replicated to multiple servers and completed only when all of them are acked.
+ * Ability to add and/or remove servers from the working set at run-time.
+ * Strong authentification and possible data encryption in network channel.
+ * Extended attributes support.
+
+POHMELFS is based on transactions, which are potentially long-standing objects that live
+in the client's memory. Each transaction contains all the information needed to process a given
+command (or set of commands, which is frequently used during data writing: single transactions
+can contain creation and data writing commands). Transactions are committed by all the servers
+to which they are sent and, in case of failures, are eventually resent or dropped with an error.
+For example, reading will return an error if no servers are available.
+
+POHMELFS uses a asynchronous approach to data processing. Courtesy of transactions, it is
+possible to detach replies from requests and, if the command requires data to be received, the
+caller sleeps waiting for it. Thus, it is possible to issue multiple read commands to different
+servers and async threads will pick up replies in parallel, find appropriate transactions in the
+system and put the data where it belongs (like the page or inode cache).
+
+The main feature of POHMELFS is writeback data and the metadata cache.
+Only a few non-performance critical operations use the write-through cache and
+are synchronous: hard and symbolic link creation, and object rename. Creation,
+removal of objects and data writing are asynchronous and are sent to
+the server during system writeback. Only one writer at a time is allowed for any
+given inode, which is guarded by an appropriate locking protocol.
+Because of this feature, POHMELFS is extremely fast at metadata intensive
+workloads and can fully utilize the bandwidth to the servers when doing bulk
+data transfers.
+
+POHMELFS clients operate with a working set of servers and are capable of balancing read-only
+operations (like lookups or directory listings) between them according to IO priorities.
+Administrators can add or remove servers from the set at run-time via special commands (described
+in Documentation/pohmelfs/info.txt file). Writes are replicated to all servers, which are connected
+with write permission turned on. IO priority and permissions can be changed in run-time.
+
+POHMELFS is capable of full data channel encryption and/or strong crypto hashing.
+One can select any kernel supported cipher, encryption mode, hash type and operation mode
+(hmac or digest). It is also possible to use both or neither (default). Crypto configuration
+is checked during mount time and, if the server does not support it, appropriate capabilities
+will be disabled or mount will fail (if 'crypto_fail_unsupported' mount option is specified).
+Crypto performance heavily depends on the number of crypto threads, which asynchronously perform
+crypto operations and send the resulting data to server or submit it up the stack. This number
+can be controlled via a mount option.

Documentation/filesystems/pohmelfs/info.txt

@@ -0,0 +1,99 @@
+POHMELFS usage information.
+
+Mount options.
+All but index, number of crypto threads and maximum IO size can changed via remount.
+
+idx=%u
+ Each mountpoint is associated with a special index via this option.
+ Administrator can add or remove servers from the given index, so all mounts,
+ which were attached to it, are updated.
+ Default it is 0.
+
+trans_scan_timeout=%u
+ This timeout, expressed in milliseconds, specifies time to scan transaction
+ trees looking for stale requests, which have to be resent, or if number of
+ retries exceed specified limit, dropped with error.
+ Default is 5 seconds.
+
+drop_scan_timeout=%u
+ Internal timeout, expressed in milliseconds, which specifies how frequently
+ inodes marked to be dropped are freed. It also specifies how frequently
+ the system checks that servers have to be added or removed from current working set.
+ Default is 1 second.
+
+wait_on_page_timeout=%u
+ Number of milliseconds to wait for reply from remote server for data reading command.
+ If this timeout is exceeded, reading returns an error.
+ Default is 5 seconds.
+
+trans_retries=%u
+ This is the number of times that a transaction will be resent to a server that did
+ not answer for the last @trans_scan_timeout milliseconds.
+ When the number of resends exceeds this limit, the transaction is completed with error.
+ Default is 5 resends.
+
+crypto_thread_num=%u
+ Number of crypto processing threads. Threads are used both for RX and TX traffic.
+ Default is 2, or no threads if crypto operations are not supported.
+
+trans_max_pages=%u
+ Maximum number of pages in a single transaction. This parameter also controls
+ the number of pages,  allocated for crypto processing (each crypto thread has
+ pool of pages, the number of which is equal to 'trans_max_pages'.
+ Default is 100 pages.
+
+crypto_fail_unsupported
+ If specified, mount will fail if the server does not support requested crypto operations.
+ By default mount will disable non-matching crypto operations.
+
+mcache_timeout=%u
+ Maximum number of milliseconds to wait for the mcache objects to be processed.
+ Mcache includes locks (given lock should be granted by server), attributes (they should be
+ fully received in the given timeframe).
+ Default is 5 seconds.
+
+Usage examples.
+
+Add server server1.net:1025 into the working set with index $idx
+with appropriate hash algorithm and key file and cipher algorithm, mode and key file:
+$cfg A add -a server1.net -p 1025 -i $idx -K $hash_key -k $cipher_key
+
+Mount filesystem with given index $idx to /mnt mountpoint.
+Client will connect to all servers specified in the working set via previous command:
+mount -t pohmel -o idx=$idx q /mnt
+
+Change permissions to read-only (-I 1 option, '-I 2' - write-only, 3 - rw):
+$cfg A modify -a server1.net -p 1025 -i $idx -I 1
+
+Change IO priority to 123 (node with the highest priority gets read requests).
+$cfg A modify -a server1.net -p 1025 -i $idx -P 123
+
+One can check currect status of all connections in the mountstats file:
+# cat /proc/$PID/mountstats
+...
+device none mounted on /mnt with fstype pohmel
+idx addr(:port) socket_type protocol active priority permissions
+0 server1.net:1026 1 6 1 250 1
+0 server2.net:1025 1 6 1 123 3
+
+Server installation.
+
+Creating a server, which listens at port 1025 and 0.0.0.0 address.
+Working root directory (note, that server chroots there, so you have to have appropriate permissions)
+is set to /mnt, server will negotiate hash/cipher with client, in case client requested it, there
+are appropriate key files.
+Number of working threads is set to 10.
+
+# ./fserver -a 0.0.0.0 -p 1025 -r /mnt -w 10 -K hash_key -k cipher_key
+
+ -A 6			 - listen on ipv6 address. Default: Disabled.
+ -r root                 - path to root directory. Default: /tmp.
+ -a addr                 - listen address. Default: 0.0.0.0.
+ -p port                 - listen port. Default: 1025.
+ -w workers              - number of workers per connected client. Default: 1.
+ -K file		 - hash key size. Default: none.
+ -k file		 - cipher key size. Default: none.
+ -h                      - this help.
+
+Number of worker threads specifies how many workers will be created for each client.
+Bulk single-client transafers usually are better handled with smaller number (like 1-3).

Documentation/filesystems/pohmelfs/network_protocol.txt

@@ -0,0 +1,227 @@
+POHMELFS network protocol.
+
+Basic structure used in network communication is following command:
+
+struct netfs_cmd
+{
+	__u16			cmd;	/* Command number */
+	__u16			csize;	/* Attached crypto information size */
+	__u16			cpad;	/* Attached padding size */
+	__u16			ext;	/* External flags */
+	__u32			size;	/* Size of the attached data */
+	__u32			trans;	/* Transaction id */
+	__u64			id;	/* Object ID to operate on. Used for feedback.*/
+	__u64			start;	/* Start of the object. */
+	__u64			iv;	/* IV sequence */
+	__u8			data[0];
+};
+
+Commands can be embedded into transaction command (which in turn has own command),
+so one can extend protocol as needed without breaking backward compatibility as long
+as old commands are supported. All string lengths include tail 0 byte.
+
+All commans are transfered over the network in big-endian. CPU endianess is used at the end peers.
+
+@cmd - command number, which specifies command to be processed. Following
+	commands are used currently:
+
+	NETFS_READDIR	= 1,	/* Read directory for given inode number */
+	NETFS_READ_PAGE,	/* Read data page from the server */
+	NETFS_WRITE_PAGE,	/* Write data page to the server */
+	NETFS_CREATE,		/* Create directory entry */
+	NETFS_REMOVE,		/* Remove directory entry */
+	NETFS_LOOKUP,		/* Lookup single object */
+	NETFS_LINK,		/* Create a link */
+	NETFS_TRANS,		/* Transaction */
+	NETFS_OPEN,		/* Open intent */
+	NETFS_INODE_INFO,	/* Metadata cache coherency synchronization message */
+	NETFS_PAGE_CACHE,	/* Page cache invalidation message */
+	NETFS_READ_PAGES,	/* Read multiple contiguous pages in one go */
+	NETFS_RENAME,		/* Rename object */
+	NETFS_CAPABILITIES,	/* Capabilities of the client, for example supported crypto */
+	NETFS_LOCK,		/* Distributed lock message */
+	NETFS_XATTR_SET,	/* Set extended attribute */
+	NETFS_XATTR_GET,	/* Get extended attribute */
+
+@ext - external flags. Used by different commands to specify some extra arguments
+	like partial size of the embedded objects or creation flags.
+
+@size - size of the attached data. For NETFS_READ_PAGE and NETFS_READ_PAGES no data is attached,
+	but size of the requested data is incorporated here. It does not include size of the command
+	header (struct netfs_cmd) itself.
+
+@id - id of the object this command operates on. Each command can use it for own purpose.
+
+@start - start of the object this command operates on. Each command can use it for own purpose.
+
+@csize, @cpad - size and padding size of the (attached if needed) crypto information.
+
+Command specifications.
+
+@NETFS_READDIR
+This command is used to sync content of the remote dir to the client.
+
+@ext - length of the path to object.
+@size - the same.
+@id - local inode number of the directory to read.
+@start - zero.
+
+
+@NETFS_READ_PAGE
+This command is used to read data from remote server.
+Data size does not exceed local page cache size.
+
+@id - inode number.
+@start - first byte offset.
+@size - number of bytes to read plus length of the path to object.
+@ext - object path length.
+
+
+@NETFS_CREATE
+Used to create object.
+It does not require that all directories on top of the object were
+already created, it will create them automatically. Each object has
+associated @netfs_path_entry data structure, which contains creation
+mode (permissions and type) and length of the name as long as name itself.
+
+@start - 0
+@size - size of the all data structures needed to create a path
+@id - local inode number
+@ext - 0
+
+
+@NETFS_REMOVE
+Used to remove object.
+
+@ext - length of the path to object.
+@size - the same.
+@id - local inode number.
+@start - zero.
+
+
+@NETFS_LOOKUP
+Lookup information about object on server.
+
+@ext - length of the path to object.
+@size - the same.
+@id - local inode number of the directory to look object in.
+@start - local inode number of the object to look at.
+
+
+@NETFS_LINK
+Create hard of symlink.
+Command is sent as "object_path|target_path".
+
+@size - size of the above string.
+@id - parent local inode number.
+@start - 1 for symlink, 0 for hardlink.
+@ext - size of the "object_path" above.
+
+
+@NETFS_TRANS
+Transaction header.
+
+@size - incorporates all embedded command sizes including theirs header sizes.
+@start - transaction generation number - unique id used to find transaction.
+@ext - transaction flags. Unused at the moment.
+@id - 0.
+
+
+@NETFS_OPEN
+Open intent for given transaction.
+
+@id - local inode number.
+@start - 0.
+@size - path length to the object.
+@ext - open flags (O_RDWR and so on).
+
+
+@NETFS_INODE_INFO
+Metadata update command.
+It is sent to servers when attributes of the object are changed and received
+when data or metadata were updated. It operates with the following structure:
+
+struct netfs_inode_info
+{
+	unsigned int		mode;
+	unsigned int		nlink;
+	unsigned int		uid;
+	unsigned int		gid;
+	unsigned int		blocksize;
+	unsigned int		padding;
+	__u64			ino;
+	__u64			blocks;
+	__u64			rdev;
+	__u64			size;
+	__u64			version;
+};
+
+It effectively mirrors stat(2) returned data.
+
+
+@ext - path length to the object.
+@size - the same plus size of the netfs_inode_info structure.
+@id - local inode number.
+@start - 0.
+
+
+@NETFS_PAGE_CACHE
+Command is only received by clients. It contains information about
+page to be marked as not up-to-date.
+
+@id - client's inode number.
+@start - last byte of the page to be invalidated. If it is not equal to
+	current inode size, it will be vmtruncated().
+@size - 0
+@ext - 0
+
+
+@NETFS_READ_PAGES
+Used to read multiple contiguous pages in one go.
+
+@start - first byte of the contiguous region to read.
+@size - contains of two fields: lower 8 bits are used to represent page cache shift
+	used by client, another 3 bytes are used to get number of pages.
+@id - local inode number.
+@ext - path length to the object.
+
+
+@NETFS_RENAME
+Used to rename object.
+Attached data is formed into following string: "old_path|new_path".
+
+@id - local inode number.
+@start - parent inode number.
+@size - length of the above string.
+@ext - length of the old path part.
+
+
+@NETFS_CAPABILITIES
+Used to exchange crypto capabilities with server.
+If crypto capabilities are not supported by server, then client will disable it
+or fail (if 'crypto_fail_unsupported' mount options was specified).
+
+@id - superblock index. Used to specify crypto information for group of servers.
+@size - size of the attached capabilities structure.
+@start - 0.
+@size - 0.
+@scsize - 0.
+
+@NETFS_LOCK
+Used to send lock request/release messages. Although it sends byte range request
+and is capable of flushing pages based on that, it is not used, since all Linux
+filesystems lock the whole inode.
+
+@id - lock generation number.
+@start - start of the locked range.
+@size - size of the locked range.
+@ext - lock type: read/write. Not used actually. 15'th bit is used to determine,
+	if it is lock request (1) or release (0).
+
+@NETFS_XATTR_SET
+@NETFS_XATTR_GET
+Used to set/get extended attributes for given inode.
+@id - attribute generation number or xattr setting type
+@start - size of the attribute (request or attached)
+@size - name length, path len and data size for given attribute
+@ext - path length for given object

Documentation/filesystems/sysfs-pci.txt

@@ -12,6 +12,7 @@ that support it.  For example, a given bus might look like this:
      |   |-- enable
      |   |-- irq
      |   |-- local_cpus
+     |   |-- remove
      |   |-- resource
      |   |-- resource0
      |   |-- resource1
@@ -36,6 +37,7 @@ files, each with their own function.
        enable	           Whether the device is enabled (ascii, rw)
        irq		   IRQ number (ascii, ro)
        local_cpus	   nearby CPU mask (cpumask, ro)
+       remove		   remove device from kernel's list (ascii, wo)
        resource		   PCI resource host addresses (ascii, ro)
        resource0..N	   PCI resource N, if present (binary, mmap)
        resource0_wc..N_wc  PCI WC map resource N, if prefetchable (binary, mmap)
@@ -46,6 +48,7 @@ files, each with their own function.
 
   ro - read only file
   rw - file is readable and writable
+  wo - write only file
   mmap - file is mmapable
   ascii - file contains ascii text
   binary - file contains binary data
@@ -73,6 +76,13 @@ that the device must be enabled for a rom read to return data succesfully.
 In the event a driver is not bound to the device, it can be enabled using the
 'enable' file, documented above.
 
+The 'remove' file is used to remove the PCI device, by writing a non-zero
+integer to the file.  This does not involve any kind of hot-plug functionality,
+e.g. powering off the device.  The device is removed from the kernel's list of
+PCI devices, the sysfs directory for it is removed, and the device will be
+removed from any drivers attached to it. Removal of PCI root buses is
+disallowed.
+
 Accessing legacy resources through sysfs
 ----------------------------------------
 

Documentation/filesystems/udf.txt

@@ -24,6 +24,8 @@ The following mount options are supported:
 
 	gid=		Set the default group.
 	umask=		Set the default umask.
+	mode=		Set the default file permissions.
+	dmode=		Set the default directory permissions.
 	uid=		Set the default user.
 	bs=		Set the block size.
 	unhide		Show otherwise hidden files.

Documentation/filesystems/vfs.txt

@@ -277,8 +277,7 @@ or bottom half).
   unfreeze_fs: called when VFS is unlocking a filesystem and making it writable
   	again.
 
-  statfs: called when the VFS needs to get filesystem statistics. This
-	is called with the kernel lock held
+  statfs: called when the VFS needs to get filesystem statistics.
 
   remount_fs: called when the filesystem is remounted. This is called
 	with the kernel lock held

Documentation/ftrace.txt

@@ -1,1424 +0,0 @@
-		ftrace - Function Tracer
-		========================
-
-Copyright 2008 Red Hat Inc.
-   Author:   Steven Rostedt <srostedt@redhat.com>
-  License:   The GNU Free Documentation License, Version 1.2
-               (dual licensed under the GPL v2)
-Reviewers:   Elias Oltmanns, Randy Dunlap, Andrew Morton,
-	     John Kacur, and David Teigland.
-
-Written for: 2.6.28-rc2
-
-Introduction
-------------
-
-Ftrace is an internal tracer designed to help out developers and
-designers of systems to find what is going on inside the kernel.
-It can be used for debugging or analyzing latencies and performance
-issues that take place outside of user-space.
-
-Although ftrace is the function tracer, it also includes an
-infrastructure that allows for other types of tracing. Some of the
-tracers that are currently in ftrace include a tracer to trace
-context switches, the time it takes for a high priority task to
-run after it was woken up, the time interrupts are disabled, and
-more (ftrace allows for tracer plugins, which means that the list of
-tracers can always grow).
-
-
-The File System
----------------
-
-Ftrace uses the debugfs file system to hold the control files as well
-as the files to display output.
-
-To mount the debugfs system:
-
-  # mkdir /debug
-  # mount -t debugfs nodev /debug
-
-(Note: it is more common to mount at /sys/kernel/debug, but for simplicity
- this document will use /debug)
-
-That's it! (assuming that you have ftrace configured into your kernel)
-
-After mounting the debugfs, you can see a directory called
-"tracing".  This directory contains the control and output files
-of ftrace. Here is a list of some of the key files:
-
-
- Note: all time values are in microseconds.
-
-  current_tracer: This is used to set or display the current tracer
-		that is configured.
-
-  available_tracers: This holds the different types of tracers that
-		have been compiled into the kernel. The tracers
-		listed here can be configured by echoing their name
-		into current_tracer.
-
-  tracing_enabled: This sets or displays whether the current_tracer
-		is activated and tracing or not. Echo 0 into this
-		file to disable the tracer or 1 to enable it.
-
-  trace: This file holds the output of the trace in a human readable
-		format (described below).
-
-  latency_trace: This file shows the same trace but the information
-		is organized more to display possible latencies
-		in the system (described below).
-
-  trace_pipe: The output is the same as the "trace" file but this
-		file is meant to be streamed with live tracing.
-		Reads from this file will block until new data
-		is retrieved. Unlike the "trace" and "latency_trace"
-		files, this file is a consumer. This means reading
-		from this file causes sequential reads to display
-		more current data. Once data is read from this
-		file, it is consumed, and will not be read
-		again with a sequential read. The "trace" and
-		"latency_trace" files are static, and if the
-		tracer is not adding more data, they will display
-		the same information every time they are read.
-
-  trace_options: This file lets the user control the amount of data
-		that is displayed in one of the above output
-		files.
-
-  trace_max_latency: Some of the tracers record the max latency.
-		For example, the time interrupts are disabled.
-		This time is saved in this file. The max trace
-		will also be stored, and displayed by either
-		"trace" or "latency_trace".  A new max trace will
-		only be recorded if the latency is greater than
-		the value in this file. (in microseconds)
-
-  buffer_size_kb: This sets or displays the number of kilobytes each CPU
-		buffer can hold. The tracer buffers are the same size
-		for each CPU. The displayed number is the size of the
-		CPU buffer and not total size of all buffers. The
-		trace buffers are allocated in pages (blocks of memory
-		that the kernel uses for allocation, usually 4 KB in size).
-		If the last page allocated has room for more bytes
-		than requested, the rest of the page will be used,
-		making the actual allocation bigger than requested.
-		(Note, the size may not be a multiple of the page size due
-		to buffer managment overhead.)
-
-		This can only be updated when the current_tracer
-		is set to "nop".
-
-  tracing_cpumask: This is a mask that lets the user only trace
-		on specified CPUS. The format is a hex string
-		representing the CPUS.
-
-  set_ftrace_filter: When dynamic ftrace is configured in (see the
-		section below "dynamic ftrace"), the code is dynamically
-		modified (code text rewrite) to disable calling of the
-		function profiler (mcount). This lets tracing be configured
-		in with practically no overhead in performance.  This also
-		has a side effect of enabling or disabling specific functions
-		to be traced. Echoing names of functions into this file
-		will limit the trace to only those functions.
-
-  set_ftrace_notrace: This has an effect opposite to that of
-		set_ftrace_filter. Any function that is added here will not
-		be traced. If a function exists in both set_ftrace_filter
-		and set_ftrace_notrace,	the function will _not_ be traced.
-
-  set_ftrace_pid: Have the function tracer only trace a single thread.
-
-  available_filter_functions: This lists the functions that ftrace
-		has processed and can trace. These are the function
-		names that you can pass to "set_ftrace_filter" or
-		"set_ftrace_notrace". (See the section "dynamic ftrace"
-		below for more details.)
-
-
-The Tracers
------------
-
-Here is the list of current tracers that may be configured.
-
-  function - function tracer that uses mcount to trace all functions.
-
-  sched_switch - traces the context switches between tasks.
-
-  irqsoff - traces the areas that disable interrupts and saves
-  		the trace with the longest max latency.
-		See tracing_max_latency.  When a new max is recorded,
-		it replaces the old trace. It is best to view this
-		trace via the latency_trace file.
-
-  preemptoff - Similar to irqsoff but traces and records the amount of
-		time for which preemption is disabled.
-
-  preemptirqsoff - Similar to irqsoff and preemptoff, but traces and
-		 records the largest time for which irqs and/or preemption
-		 is disabled.
-
-  wakeup - Traces and records the max latency that it takes for
-		the highest priority task to get scheduled after
-		it has been woken up.
-
-  nop - This is not a tracer. To remove all tracers from tracing
-		simply echo "nop" into current_tracer.
-
-
-Examples of using the tracer
-----------------------------
-
-Here are typical examples of using the tracers when controlling them only
-with the debugfs interface (without using any user-land utilities).
-
-Output format:
---------------
-
-Here is an example of the output format of the file "trace"
-
-                             --------
-# tracer: function
-#
-#           TASK-PID   CPU#    TIMESTAMP  FUNCTION
-#              | |      |          |         |
-            bash-4251  [01] 10152.583854: path_put <-path_walk
-            bash-4251  [01] 10152.583855: dput <-path_put
-            bash-4251  [01] 10152.583855: _atomic_dec_and_lock <-dput
-                             --------
-
-A header is printed with the tracer name that is represented by the trace.
-In this case the tracer is "function". Then a header showing the format. Task
-name "bash", the task PID "4251", the CPU that it was running on
-"01", the timestamp in <secs>.<usecs> format, the function name that was
-traced "path_put" and the parent function that called this function
-"path_walk". The timestamp is the time at which the function was
-entered.
-
-The sched_switch tracer also includes tracing of task wakeups and
-context switches.
-
-     ksoftirqd/1-7     [01]  1453.070013:      7:115:R   +  2916:115:S
-     ksoftirqd/1-7     [01]  1453.070013:      7:115:R   +    10:115:S
-     ksoftirqd/1-7     [01]  1453.070013:      7:115:R ==>    10:115:R
-        events/1-10    [01]  1453.070013:     10:115:S ==>  2916:115:R
-     kondemand/1-2916  [01]  1453.070013:   2916:115:S ==>     7:115:R
-     ksoftirqd/1-7     [01]  1453.070013:      7:115:S ==>     0:140:R
-
-Wake ups are represented by a "+" and the context switches are shown as
-"==>".  The format is:
-
- Context switches:
-
-       Previous task              Next Task
-
-  <pid>:<prio>:<state>  ==>  <pid>:<prio>:<state>
-
- Wake ups:
-
-       Current task               Task waking up
-
-  <pid>:<prio>:<state>    +  <pid>:<prio>:<state>
-
-The prio is the internal kernel priority, which is the inverse of the
-priority that is usually displayed by user-space tools. Zero represents
-the highest priority (99). Prio 100 starts the "nice" priorities with
-100 being equal to nice -20 and 139 being nice 19. The prio "140" is
-reserved for the idle task which is the lowest priority thread (pid 0).
-
-
-Latency trace format
---------------------
-
-For traces that display latency times, the latency_trace file gives
-somewhat more information to see why a latency happened. Here is a typical
-trace.
-
-# tracer: irqsoff
-#
-irqsoff latency trace v1.1.5 on 2.6.26-rc8
---------------------------------------------------------------------
- latency: 97 us, #3/3, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
-    -----------------
-    | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0)
-    -----------------
- => started at: apic_timer_interrupt
- => ended at:   do_softirq
-
-#                _------=> CPU#
-#               / _-----=> irqs-off
-#              | / _----=> need-resched
-#              || / _---=> hardirq/softirq
-#              ||| / _--=> preempt-depth
-#              |||| /
-#              |||||     delay
-#  cmd     pid ||||| time  |   caller
-#     \   /    |||||   \   |   /
-  <idle>-0     0d..1    0us+: trace_hardirqs_off_thunk (apic_timer_interrupt)
-  <idle>-0     0d.s.   97us : __do_softirq (do_softirq)
-  <idle>-0     0d.s1   98us : trace_hardirqs_on (do_softirq)
-
-
-
-This shows that the current tracer is "irqsoff" tracing the time for which
-interrupts were disabled. It gives the trace version and the version
-of the kernel upon which this was executed on (2.6.26-rc8). Then it displays
-the max latency in microsecs (97 us). The number of trace entries displayed
-and the total number recorded (both are three: #3/3). The type of
-preemption that was used (PREEMPT). VP, KP, SP, and HP are always zero
-and are reserved for later use. #P is the number of online CPUS (#P:2).
-
-The task is the process that was running when the latency occurred.
-(swapper pid: 0).
-
-The start and stop (the functions in which the interrupts were disabled and
-enabled respectively) that caused the latencies:
-
-  apic_timer_interrupt is where the interrupts were disabled.
-  do_softirq is where they were enabled again.
-
-The next lines after the header are the trace itself. The header
-explains which is which.
-
-  cmd: The name of the process in the trace.
-
-  pid: The PID of that process.
-
-  CPU#: The CPU which the process was running on.
-
-  irqs-off: 'd' interrupts are disabled. '.' otherwise.
-	    Note: If the architecture does not support a way to
-		  read the irq flags variable, an 'X' will always
-		  be printed here.
-
-  need-resched: 'N' task need_resched is set, '.' otherwise.
-
-  hardirq/softirq:
-	'H' - hard irq occurred inside a softirq.
-	'h' - hard irq is running
-	's' - soft irq is running
-	'.' - normal context.
-
-  preempt-depth: The level of preempt_disabled
-
-The above is mostly meaningful for kernel developers.
-
-  time: This differs from the trace file output. The trace file output
-	includes an absolute timestamp. The timestamp used by the
-	latency_trace file is relative to the start of the trace.
-
-  delay: This is just to help catch your eye a bit better. And
-	needs to be fixed to be only relative to the same CPU.
-	The marks are determined by the difference between this
-	current trace and the next trace.
-	 '!' - greater than preempt_mark_thresh (default 100)
-	 '+' - greater than 1 microsecond
-	 ' ' - less than or equal to 1 microsecond.
-
-  The rest is the same as the 'trace' file.
-
-
-trace_options
--------------
-
-The trace_options file is used to control what gets printed in the trace
-output. To see what is available, simply cat the file:
-
-  cat /debug/tracing/trace_options
-  print-parent nosym-offset nosym-addr noverbose noraw nohex nobin \
- noblock nostacktrace nosched-tree nouserstacktrace nosym-userobj
-
-To disable one of the options, echo in the option prepended with "no".
-
-  echo noprint-parent > /debug/tracing/trace_options
-
-To enable an option, leave off the "no".
-
-  echo sym-offset > /debug/tracing/trace_options
-
-Here are the available options:
-
-  print-parent - On function traces, display the calling function
-		as well as the function being traced.
-
-  print-parent:
-   bash-4000  [01]  1477.606694: simple_strtoul <-strict_strtoul
-
-  noprint-parent:
-   bash-4000  [01]  1477.606694: simple_strtoul
-
-
-  sym-offset - Display not only the function name, but also the offset
-		in the function. For example, instead of seeing just
-		"ktime_get", you will see "ktime_get+0xb/0x20".
-
-  sym-offset:
-   bash-4000  [01]  1477.606694: simple_strtoul+0x6/0xa0
-
-  sym-addr - this will also display the function address as well as
-		the function name.
-
-  sym-addr:
-   bash-4000  [01]  1477.606694: simple_strtoul <c0339346>
-
-  verbose - This deals with the latency_trace file.
-
-    bash  4000 1 0 00000000 00010a95 [58127d26] 1720.415ms \
-    (+0.000ms): simple_strtoul (strict_strtoul)
-
-  raw - This will display raw numbers. This option is best for use with
-	user applications that can translate the raw numbers better than
-	having it done in the kernel.
-
-  hex - Similar to raw, but the numbers will be in a hexadecimal format.
-
-  bin - This will print out the formats in raw binary.
-
-  block - TBD (needs update)
-
-  stacktrace - This is one of the options that changes the trace itself.
-		When a trace is recorded, so is the stack of functions.
-		This allows for back traces of trace sites.
-
-  userstacktrace - This option changes the trace.
-		   It records a stacktrace of the current userspace thread.
-
-  sym-userobj - when user stacktrace are enabled, look up which object the
-		address belongs to, and print a relative address
-		This is especially useful when ASLR is on, otherwise you don't
-		get a chance to resolve the address to object/file/line after the app is no
-		longer running
-
-		The lookup is performed when you read trace,trace_pipe,latency_trace. Example:
-
-		a.out-1623  [000] 40874.465068: /root/a.out[+0x480] <-/root/a.out[+0
-x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6]
-
-  sched-tree - TBD (any users??)
-
-
-sched_switch
-------------
-
-This tracer simply records schedule switches. Here is an example
-of how to use it.
-
- # echo sched_switch > /debug/tracing/current_tracer
- # echo 1 > /debug/tracing/tracing_enabled
- # sleep 1
- # echo 0 > /debug/tracing/tracing_enabled
- # cat /debug/tracing/trace
-
-# tracer: sched_switch
-#
-#           TASK-PID   CPU#    TIMESTAMP  FUNCTION
-#              | |      |          |         |
-            bash-3997  [01]   240.132281:   3997:120:R   +  4055:120:R
-            bash-3997  [01]   240.132284:   3997:120:R ==>  4055:120:R
-           sleep-4055  [01]   240.132371:   4055:120:S ==>  3997:120:R
-            bash-3997  [01]   240.132454:   3997:120:R   +  4055:120:S
-            bash-3997  [01]   240.132457:   3997:120:R ==>  4055:120:R
-           sleep-4055  [01]   240.132460:   4055:120:D ==>  3997:120:R
-            bash-3997  [01]   240.132463:   3997:120:R   +  4055:120:D
-            bash-3997  [01]   240.132465:   3997:120:R ==>  4055:120:R
-          <idle>-0     [00]   240.132589:      0:140:R   +     4:115:S
-          <idle>-0     [00]   240.132591:      0:140:R ==>     4:115:R
-     ksoftirqd/0-4     [00]   240.132595:      4:115:S ==>     0:140:R
-          <idle>-0     [00]   240.132598:      0:140:R   +     4:115:S
-          <idle>-0     [00]   240.132599:      0:140:R ==>     4:115:R
-     ksoftirqd/0-4     [00]   240.132603:      4:115:S ==>     0:140:R
-           sleep-4055  [01]   240.133058:   4055:120:S ==>  3997:120:R
- [...]
-
-
-As we have discussed previously about this format, the header shows
-the name of the trace and points to the options. The "FUNCTION"
-is a misnomer since here it represents the wake ups and context
-switches.
-
-The sched_switch file only lists the wake ups (represented with '+')
-and context switches ('==>') with the previous task or current task
-first followed by the next task or task waking up. The format for both
-of these is PID:KERNEL-PRIO:TASK-STATE. Remember that the KERNEL-PRIO
-is the inverse of the actual priority with zero (0) being the highest
-priority and the nice values starting at 100 (nice -20). Below is
-a quick chart to map the kernel priority to user land priorities.
-
-  Kernel priority: 0 to 99    ==> user RT priority 99 to 0
-  Kernel priority: 100 to 139 ==> user nice -20 to 19
-  Kernel priority: 140        ==> idle task priority
-
-The task states are:
-
- R - running : wants to run, may not actually be running
- S - sleep   : process is waiting to be woken up (handles signals)
- D - disk sleep (uninterruptible sleep) : process must be woken up
-					(ignores signals)
- T - stopped : process suspended
- t - traced  : process is being traced (with something like gdb)
- Z - zombie  : process waiting to be cleaned up
- X - unknown
-
-
-ftrace_enabled
---------------
-
-The following tracers (listed below) give different output depending
-on whether or not the sysctl ftrace_enabled is set. To set ftrace_enabled,
-one can either use the sysctl function or set it via the proc
-file system interface.
-
-  sysctl kernel.ftrace_enabled=1
-
- or
-
-  echo 1 > /proc/sys/kernel/ftrace_enabled
-
-To disable ftrace_enabled simply replace the '1' with '0' in
-the above commands.
-
-When ftrace_enabled is set the tracers will also record the functions
-that are within the trace. The descriptions of the tracers
-will also show an example with ftrace enabled.
-
-
-irqsoff
--------
-
-When interrupts are disabled, the CPU can not react to any other
-external event (besides NMIs and SMIs). This prevents the timer
-interrupt from triggering or the mouse interrupt from letting the
-kernel know of a new mouse event. The result is a latency with the
-reaction time.
-
-The irqsoff tracer tracks the time for which interrupts are disabled.
-When a new maximum latency is hit, the tracer saves the trace leading up
-to that latency point so that every time a new maximum is reached, the old
-saved trace is discarded and the new trace is saved.
-
-To reset the maximum, echo 0 into tracing_max_latency. Here is an
-example:
-
- # echo irqsoff > /debug/tracing/current_tracer
- # echo 0 > /debug/tracing/tracing_max_latency
- # echo 1 > /debug/tracing/tracing_enabled
- # ls -ltr
- [...]
- # echo 0 > /debug/tracing/tracing_enabled
- # cat /debug/tracing/latency_trace
-# tracer: irqsoff
-#
-irqsoff latency trace v1.1.5 on 2.6.26
---------------------------------------------------------------------
- latency: 12 us, #3/3, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
-    -----------------
-    | task: bash-3730 (uid:0 nice:0 policy:0 rt_prio:0)
-    -----------------
- => started at: sys_setpgid
- => ended at:   sys_setpgid
-
-#                _------=> CPU#
-#               / _-----=> irqs-off
-#              | / _----=> need-resched
-#              || / _---=> hardirq/softirq
-#              ||| / _--=> preempt-depth
-#              |||| /
-#              |||||     delay
-#  cmd     pid ||||| time  |   caller
-#     \   /    |||||   \   |   /
-    bash-3730  1d...    0us : _write_lock_irq (sys_setpgid)
-    bash-3730  1d..1    1us+: _write_unlock_irq (sys_setpgid)
-    bash-3730  1d..2   14us : trace_hardirqs_on (sys_setpgid)
-
-
-Here we see that that we had a latency of 12 microsecs (which is
-very good). The _write_lock_irq in sys_setpgid disabled interrupts.
-The difference between the 12 and the displayed timestamp 14us occurred
-because the clock was incremented between the time of recording the max
-latency and the time of recording the function that had that latency.
-
-Note the above example had ftrace_enabled not set. If we set the
-ftrace_enabled, we get a much larger output:
-
-# tracer: irqsoff
-#
-irqsoff latency trace v1.1.5 on 2.6.26-rc8
---------------------------------------------------------------------
- latency: 50 us, #101/101, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
-    -----------------
-    | task: ls-4339 (uid:0 nice:0 policy:0 rt_prio:0)
-    -----------------
- => started at: __alloc_pages_internal
- => ended at:   __alloc_pages_internal
-
-#                _------=> CPU#
-#               / _-----=> irqs-off
-#              | / _----=> need-resched
-#              || / _---=> hardirq/softirq
-#              ||| / _--=> preempt-depth
-#              |||| /
-#              |||||     delay
-#  cmd     pid ||||| time  |   caller
-#     \   /    |||||   \   |   /
-      ls-4339  0...1    0us+: get_page_from_freelist (__alloc_pages_internal)
-      ls-4339  0d..1    3us : rmqueue_bulk (get_page_from_freelist)
-      ls-4339  0d..1    3us : _spin_lock (rmqueue_bulk)
-      ls-4339  0d..1    4us : add_preempt_count (_spin_lock)
-      ls-4339  0d..2    4us : __rmqueue (rmqueue_bulk)
-      ls-4339  0d..2    5us : __rmqueue_smallest (__rmqueue)
-      ls-4339  0d..2    5us : __mod_zone_page_state (__rmqueue_smallest)
-      ls-4339  0d..2    6us : __rmqueue (rmqueue_bulk)
-      ls-4339  0d..2    6us : __rmqueue_smallest (__rmqueue)
-      ls-4339  0d..2    7us : __mod_zone_page_state (__rmqueue_smallest)
-      ls-4339  0d..2    7us : __rmqueue (rmqueue_bulk)
-      ls-4339  0d..2    8us : __rmqueue_smallest (__rmqueue)
-[...]
-      ls-4339  0d..2   46us : __rmqueue_smallest (__rmqueue)
-      ls-4339  0d..2   47us : __mod_zone_page_state (__rmqueue_smallest)
-      ls-4339  0d..2   47us : __rmqueue (rmqueue_bulk)
-      ls-4339  0d..2   48us : __rmqueue_smallest (__rmqueue)
-      ls-4339  0d..2   48us : __mod_zone_page_state (__rmqueue_smallest)
-      ls-4339  0d..2   49us : _spin_unlock (rmqueue_bulk)
-      ls-4339  0d..2   49us : sub_preempt_count (_spin_unlock)
-      ls-4339  0d..1   50us : get_page_from_freelist (__alloc_pages_internal)
-      ls-4339  0d..2   51us : trace_hardirqs_on (__alloc_pages_internal)
-
-
-
-Here we traced a 50 microsecond latency. But we also see all the
-functions that were called during that time. Note that by enabling
-function tracing, we incur an added overhead. This overhead may
-extend the latency times. But nevertheless, this trace has provided
-some very helpful debugging information.
-
-
-preemptoff
-----------
-
-When preemption is disabled, we may be able to receive interrupts but
-the task cannot be preempted and a higher priority task must wait
-for preemption to be enabled again before it can preempt a lower
-priority task.
-
-The preemptoff tracer traces the places that disable preemption.
-Like the irqsoff tracer, it records the maximum latency for which preemption
-was disabled. The control of preemptoff tracer is much like the irqsoff
-tracer.
-
- # echo preemptoff > /debug/tracing/current_tracer
- # echo 0 > /debug/tracing/tracing_max_latency
- # echo 1 > /debug/tracing/tracing_enabled
- # ls -ltr
- [...]
- # echo 0 > /debug/tracing/tracing_enabled
- # cat /debug/tracing/latency_trace
-# tracer: preemptoff
-#
-preemptoff latency trace v1.1.5 on 2.6.26-rc8
---------------------------------------------------------------------
- latency: 29 us, #3/3, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
-    -----------------
-    | task: sshd-4261 (uid:0 nice:0 policy:0 rt_prio:0)
-    -----------------
- => started at: do_IRQ
- => ended at:   __do_softirq
-
-#                _------=> CPU#
-#               / _-----=> irqs-off
-#              | / _----=> need-resched
-#              || / _---=> hardirq/softirq
-#              ||| / _--=> preempt-depth
-#              |||| /
-#              |||||     delay
-#  cmd     pid ||||| time  |   caller
-#     \   /    |||||   \   |   /
-    sshd-4261  0d.h.    0us+: irq_enter (do_IRQ)
-    sshd-4261  0d.s.   29us : _local_bh_enable (__do_softirq)
-    sshd-4261  0d.s1   30us : trace_preempt_on (__do_softirq)
-
-
-This has some more changes. Preemption was disabled when an interrupt
-came in (notice the 'h'), and was enabled while doing a softirq.
-(notice the 's'). But we also see that interrupts have been disabled
-when entering the preempt off section and leaving it (the 'd').
-We do not know if interrupts were enabled in the mean time.
-
-# tracer: preemptoff
-#
-preemptoff latency trace v1.1.5 on 2.6.26-rc8
---------------------------------------------------------------------
- latency: 63 us, #87/87, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
-    -----------------
-    | task: sshd-4261 (uid:0 nice:0 policy:0 rt_prio:0)
-    -----------------
- => started at: remove_wait_queue
- => ended at:   __do_softirq
-
-#                _------=> CPU#
-#               / _-----=> irqs-off
-#              | / _----=> need-resched
-#              || / _---=> hardirq/softirq
-#              ||| / _--=> preempt-depth
-#              |||| /
-#              |||||     delay
-#  cmd     pid ||||| time  |   caller
-#     \   /    |||||   \   |   /
-    sshd-4261  0d..1    0us : _spin_lock_irqsave (remove_wait_queue)
-    sshd-4261  0d..1    1us : _spin_unlock_irqrestore (remove_wait_queue)
-    sshd-4261  0d..1    2us : do_IRQ (common_interrupt)
-    sshd-4261  0d..1    2us : irq_enter (do_IRQ)
-    sshd-4261  0d..1    2us : idle_cpu (irq_enter)
-    sshd-4261  0d..1    3us : add_preempt_count (irq_enter)
-    sshd-4261  0d.h1    3us : idle_cpu (irq_enter)
-    sshd-4261  0d.h.    4us : handle_fasteoi_irq (do_IRQ)
-[...]
-    sshd-4261  0d.h.   12us : add_preempt_count (_spin_lock)
-    sshd-4261  0d.h1   12us : ack_ioapic_quirk_irq (handle_fasteoi_irq)
-    sshd-4261  0d.h1   13us : move_native_irq (ack_ioapic_quirk_irq)
-    sshd-4261  0d.h1   13us : _spin_unlock (handle_fasteoi_irq)
-    sshd-4261  0d.h1   14us : sub_preempt_count (_spin_unlock)
-    sshd-4261  0d.h1   14us : irq_exit (do_IRQ)
-    sshd-4261  0d.h1   15us : sub_preempt_count (irq_exit)
-    sshd-4261  0d..2   15us : do_softirq (irq_exit)
-    sshd-4261  0d...   15us : __do_softirq (do_softirq)
-    sshd-4261  0d...   16us : __local_bh_disable (__do_softirq)
-    sshd-4261  0d...   16us+: add_preempt_count (__local_bh_disable)
-    sshd-4261  0d.s4   20us : add_preempt_count (__local_bh_disable)
-    sshd-4261  0d.s4   21us : sub_preempt_count (local_bh_enable)
-    sshd-4261  0d.s5   21us : sub_preempt_count (local_bh_enable)
-[...]
-    sshd-4261  0d.s6   41us : add_preempt_count (__local_bh_disable)
-    sshd-4261  0d.s6   42us : sub_preempt_count (local_bh_enable)
-    sshd-4261  0d.s7   42us : sub_preempt_count (local_bh_enable)
-    sshd-4261  0d.s5   43us : add_preempt_count (__local_bh_disable)
-    sshd-4261  0d.s5   43us : sub_preempt_count (local_bh_enable_ip)
-    sshd-4261  0d.s6   44us : sub_preempt_count (local_bh_enable_ip)
-    sshd-4261  0d.s5   44us : add_preempt_count (__local_bh_disable)
-    sshd-4261  0d.s5   45us : sub_preempt_count (local_bh_enable)
-[...]
-    sshd-4261  0d.s.   63us : _local_bh_enable (__do_softirq)
-    sshd-4261  0d.s1   64us : trace_preempt_on (__do_softirq)
-
-
-The above is an example of the preemptoff trace with ftrace_enabled
-set. Here we see that interrupts were disabled the entire time.
-The irq_enter code lets us know that we entered an interrupt 'h'.
-Before that, the functions being traced still show that it is not
-in an interrupt, but we can see from the functions themselves that
-this is not the case.
-
-Notice that __do_softirq when called does not have a preempt_count.
-It may seem that we missed a preempt enabling. What really happened
-is that the preempt count is held on the thread's stack and we
-switched to the softirq stack (4K stacks in effect). The code
-does not copy the preempt count, but because interrupts are disabled,
-we do not need to worry about it. Having a tracer like this is good
-for letting people know what really happens inside the kernel.
-
-
-preemptirqsoff
---------------
-
-Knowing the locations that have interrupts disabled or preemption
-disabled for the longest times is helpful. But sometimes we would
-like to know when either preemption and/or interrupts are disabled.
-
-Consider the following code:
-
-    local_irq_disable();
-    call_function_with_irqs_off();
-    preempt_disable();
-    call_function_with_irqs_and_preemption_off();
-    local_irq_enable();
-    call_function_with_preemption_off();
-    preempt_enable();
-
-The irqsoff tracer will record the total length of
-call_function_with_irqs_off() and
-call_function_with_irqs_and_preemption_off().
-
-The preemptoff tracer will record the total length of
-call_function_with_irqs_and_preemption_off() and
-call_function_with_preemption_off().
-
-But neither will trace the time that interrupts and/or preemption
-is disabled. This total time is the time that we can not schedule.
-To record this time, use the preemptirqsoff tracer.
-
-Again, using this trace is much like the irqsoff and preemptoff tracers.
-
- # echo preemptirqsoff > /debug/tracing/current_tracer
- # echo 0 > /debug/tracing/tracing_max_latency
- # echo 1 > /debug/tracing/tracing_enabled
- # ls -ltr
- [...]
- # echo 0 > /debug/tracing/tracing_enabled
- # cat /debug/tracing/latency_trace
-# tracer: preemptirqsoff
-#
-preemptirqsoff latency trace v1.1.5 on 2.6.26-rc8
---------------------------------------------------------------------
- latency: 293 us, #3/3, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
-    -----------------
-    | task: ls-4860 (uid:0 nice:0 policy:0 rt_prio:0)
-    -----------------
- => started at: apic_timer_interrupt
- => ended at:   __do_softirq
-
-#                _------=> CPU#
-#               / _-----=> irqs-off
-#              | / _----=> need-resched
-#              || / _---=> hardirq/softirq
-#              ||| / _--=> preempt-depth
-#              |||| /
-#              |||||     delay
-#  cmd     pid ||||| time  |   caller
-#     \   /    |||||   \   |   /
-      ls-4860  0d...    0us!: trace_hardirqs_off_thunk (apic_timer_interrupt)
-      ls-4860  0d.s.  294us : _local_bh_enable (__do_softirq)
-      ls-4860  0d.s1  294us : trace_preempt_on (__do_softirq)
-
-
-
-The trace_hardirqs_off_thunk is called from assembly on x86 when
-interrupts are disabled in the assembly code. Without the function
-tracing, we do not know if interrupts were enabled within the preemption
-points. We do see that it started with preemption enabled.
-
-Here is a trace with ftrace_enabled set:
-
-
-# tracer: preemptirqsoff
-#
-preemptirqsoff latency trace v1.1.5 on 2.6.26-rc8
---------------------------------------------------------------------
- latency: 105 us, #183/183, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
-    -----------------
-    | task: sshd-4261 (uid:0 nice:0 policy:0 rt_prio:0)
-    -----------------
- => started at: write_chan
- => ended at:   __do_softirq
-
-#                _------=> CPU#
-#               / _-----=> irqs-off
-#              | / _----=> need-resched
-#              || / _---=> hardirq/softirq
-#              ||| / _--=> preempt-depth
-#              |||| /
-#              |||||     delay
-#  cmd     pid ||||| time  |   caller
-#     \   /    |||||   \   |   /
-      ls-4473  0.N..    0us : preempt_schedule (write_chan)
-      ls-4473  0dN.1    1us : _spin_lock (schedule)
-      ls-4473  0dN.1    2us : add_preempt_count (_spin_lock)
-      ls-4473  0d..2    2us : put_prev_task_fair (schedule)
-[...]
-      ls-4473  0d..2   13us : set_normalized_timespec (ktime_get_ts)
-      ls-4473  0d..2   13us : __switch_to (schedule)
-    sshd-4261  0d..2   14us : finish_task_switch (schedule)
-    sshd-4261  0d..2   14us : _spin_unlock_irq (finish_task_switch)
-    sshd-4261  0d..1   15us : add_preempt_count (_spin_lock_irqsave)
-    sshd-4261  0d..2   16us : _spin_unlock_irqrestore (hrtick_set)
-    sshd-4261  0d..2   16us : do_IRQ (common_interrupt)
-    sshd-4261  0d..2   17us : irq_enter (do_IRQ)
-    sshd-4261  0d..2   17us : idle_cpu (irq_enter)
-    sshd-4261  0d..2   18us : add_preempt_count (irq_enter)
-    sshd-4261  0d.h2   18us : idle_cpu (irq_enter)
-    sshd-4261  0d.h.   18us : handle_fasteoi_irq (do_IRQ)
-    sshd-4261  0d.h.   19us : _spin_lock (handle_fasteoi_irq)
-    sshd-4261  0d.h.   19us : add_preempt_count (_spin_lock)
-    sshd-4261  0d.h1   20us : _spin_unlock (handle_fasteoi_irq)
-    sshd-4261  0d.h1   20us : sub_preempt_count (_spin_unlock)
-[...]
-    sshd-4261  0d.h1   28us : _spin_unlock (handle_fasteoi_irq)
-    sshd-4261  0d.h1   29us : sub_preempt_count (_spin_unlock)
-    sshd-4261  0d.h2   29us : irq_exit (do_IRQ)
-    sshd-4261  0d.h2   29us : sub_preempt_count (irq_exit)
-    sshd-4261  0d..3   30us : do_softirq (irq_exit)
-    sshd-4261  0d...   30us : __do_softirq (do_softirq)
-    sshd-4261  0d...   31us : __local_bh_disable (__do_softirq)
-    sshd-4261  0d...   31us+: add_preempt_count (__local_bh_disable)
-    sshd-4261  0d.s4   34us : add_preempt_count (__local_bh_disable)
-[...]
-    sshd-4261  0d.s3   43us : sub_preempt_count (local_bh_enable_ip)
-    sshd-4261  0d.s4   44us : sub_preempt_count (local_bh_enable_ip)
-    sshd-4261  0d.s3   44us : smp_apic_timer_interrupt (apic_timer_interrupt)
-    sshd-4261  0d.s3   45us : irq_enter (smp_apic_timer_interrupt)
-    sshd-4261  0d.s3   45us : idle_cpu (irq_enter)
-    sshd-4261  0d.s3   46us : add_preempt_count (irq_enter)
-    sshd-4261  0d.H3   46us : idle_cpu (irq_enter)
-    sshd-4261  0d.H3   47us : hrtimer_interrupt (smp_apic_timer_interrupt)
-    sshd-4261  0d.H3   47us : ktime_get (hrtimer_interrupt)
-[...]
-    sshd-4261  0d.H3   81us : tick_program_event (hrtimer_interrupt)
-    sshd-4261  0d.H3   82us : ktime_get (tick_program_event)
-    sshd-4261  0d.H3   82us : ktime_get_ts (ktime_get)
-    sshd-4261  0d.H3   83us : getnstimeofday (ktime_get_ts)
-    sshd-4261  0d.H3   83us : set_normalized_timespec (ktime_get_ts)
-    sshd-4261  0d.H3   84us : clockevents_program_event (tick_program_event)
-    sshd-4261  0d.H3   84us : lapic_next_event (clockevents_program_event)
-    sshd-4261  0d.H3   85us : irq_exit (smp_apic_timer_interrupt)
-    sshd-4261  0d.H3   85us : sub_preempt_count (irq_exit)
-    sshd-4261  0d.s4   86us : sub_preempt_count (irq_exit)
-    sshd-4261  0d.s3   86us : add_preempt_count (__local_bh_disable)
-[...]
-    sshd-4261  0d.s1   98us : sub_preempt_count (net_rx_action)
-    sshd-4261  0d.s.   99us : add_preempt_count (_spin_lock_irq)
-    sshd-4261  0d.s1   99us+: _spin_unlock_irq (run_timer_softirq)
-    sshd-4261  0d.s.  104us : _local_bh_enable (__do_softirq)
-    sshd-4261  0d.s.  104us : sub_preempt_count (_local_bh_enable)
-    sshd-4261  0d.s.  105us : _local_bh_enable (__do_softirq)
-    sshd-4261  0d.s1  105us : trace_preempt_on (__do_softirq)
-
-
-This is a very interesting trace. It started with the preemption of
-the ls task. We see that the task had the "need_resched" bit set
-via the 'N' in the trace.  Interrupts were disabled before the spin_lock
-at the beginning of the trace. We see that a schedule took place to run
-sshd.  When the interrupts were enabled, we took an interrupt.
-On return from the interrupt handler, the softirq ran. We took another
-interrupt while running the softirq as we see from the capital 'H'.
-
-
-wakeup
-------
-
-In a Real-Time environment it is very important to know the wakeup
-time it takes for the highest priority task that is woken up to the
-time that it executes. This is also known as "schedule latency".
-I stress the point that this is about RT tasks. It is also important
-to know the scheduling latency of non-RT tasks, but the average
-schedule latency is better for non-RT tasks. Tools like
-LatencyTop are more appropriate for such measurements.
-
-Real-Time environments are interested in the worst case latency.
-That is the longest latency it takes for something to happen, and
-not the average. We can have a very fast scheduler that may only
-have a large latency once in a while, but that would not work well
-with Real-Time tasks.  The wakeup tracer was designed to record
-the worst case wakeups of RT tasks. Non-RT tasks are not recorded
-because the tracer only records one worst case and tracing non-RT
-tasks that are unpredictable will overwrite the worst case latency
-of RT tasks.
-
-Since this tracer only deals with RT tasks, we will run this slightly
-differently than we did with the previous tracers. Instead of performing
-an 'ls', we will run 'sleep 1' under 'chrt' which changes the
-priority of the task.
-
- # echo wakeup > /debug/tracing/current_tracer
- # echo 0 > /debug/tracing/tracing_max_latency
- # echo 1 > /debug/tracing/tracing_enabled
- # chrt -f 5 sleep 1
- # echo 0 > /debug/tracing/tracing_enabled
- # cat /debug/tracing/latency_trace
-# tracer: wakeup
-#
-wakeup latency trace v1.1.5 on 2.6.26-rc8
---------------------------------------------------------------------
- latency: 4 us, #2/2, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
-    -----------------
-    | task: sleep-4901 (uid:0 nice:0 policy:1 rt_prio:5)
-    -----------------
-
-#                _------=> CPU#
-#               / _-----=> irqs-off
-#              | / _----=> need-resched
-#              || / _---=> hardirq/softirq
-#              ||| / _--=> preempt-depth
-#              |||| /
-#              |||||     delay
-#  cmd     pid ||||| time  |   caller
-#     \   /    |||||   \   |   /
-  <idle>-0     1d.h4    0us+: try_to_wake_up (wake_up_process)
-  <idle>-0     1d..4    4us : schedule (cpu_idle)
-
-
-
-Running this on an idle system, we see that it only took 4 microseconds
-to perform the task switch.  Note, since the trace marker in the
-schedule is before the actual "switch", we stop the tracing when
-the recorded task is about to schedule in. This may change if
-we add a new marker at the end of the scheduler.
-
-Notice that the recorded task is 'sleep' with the PID of 4901 and it
-has an rt_prio of 5. This priority is user-space priority and not
-the internal kernel priority. The policy is 1 for SCHED_FIFO and 2
-for SCHED_RR.
-
-Doing the same with chrt -r 5 and ftrace_enabled set.
-
-# tracer: wakeup
-#
-wakeup latency trace v1.1.5 on 2.6.26-rc8
---------------------------------------------------------------------
- latency: 50 us, #60/60, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
-    -----------------
-    | task: sleep-4068 (uid:0 nice:0 policy:2 rt_prio:5)
-    -----------------
-
-#                _------=> CPU#
-#               / _-----=> irqs-off
-#              | / _----=> need-resched
-#              || / _---=> hardirq/softirq
-#              ||| / _--=> preempt-depth
-#              |||| /
-#              |||||     delay
-#  cmd     pid ||||| time  |   caller
-#     \   /    |||||   \   |   /
-ksoftirq-7     1d.H3    0us : try_to_wake_up (wake_up_process)
-ksoftirq-7     1d.H4    1us : sub_preempt_count (marker_probe_cb)
-ksoftirq-7     1d.H3    2us : check_preempt_wakeup (try_to_wake_up)
-ksoftirq-7     1d.H3    3us : update_curr (check_preempt_wakeup)
-ksoftirq-7     1d.H3    4us : calc_delta_mine (update_curr)
-ksoftirq-7     1d.H3    5us : __resched_task (check_preempt_wakeup)
-ksoftirq-7     1d.H3    6us : task_wake_up_rt (try_to_wake_up)
-ksoftirq-7     1d.H3    7us : _spin_unlock_irqrestore (try_to_wake_up)
-[...]
-ksoftirq-7     1d.H2   17us : irq_exit (smp_apic_timer_interrupt)
-ksoftirq-7     1d.H2   18us : sub_preempt_count (irq_exit)
-ksoftirq-7     1d.s3   19us : sub_preempt_count (irq_exit)
-ksoftirq-7     1..s2   20us : rcu_process_callbacks (__do_softirq)
-[...]
-ksoftirq-7     1..s2   26us : __rcu_process_callbacks (rcu_process_callbacks)
-ksoftirq-7     1d.s2   27us : _local_bh_enable (__do_softirq)
-ksoftirq-7     1d.s2   28us : sub_preempt_count (_local_bh_enable)
-ksoftirq-7     1.N.3   29us : sub_preempt_count (ksoftirqd)
-ksoftirq-7     1.N.2   30us : _cond_resched (ksoftirqd)
-ksoftirq-7     1.N.2   31us : __cond_resched (_cond_resched)
-ksoftirq-7     1.N.2   32us : add_preempt_count (__cond_resched)
-ksoftirq-7     1.N.2   33us : schedule (__cond_resched)
-ksoftirq-7     1.N.2   33us : add_preempt_count (schedule)
-ksoftirq-7     1.N.3   34us : hrtick_clear (schedule)
-ksoftirq-7     1dN.3   35us : _spin_lock (schedule)
-ksoftirq-7     1dN.3   36us : add_preempt_count (_spin_lock)
-ksoftirq-7     1d..4   37us : put_prev_task_fair (schedule)
-ksoftirq-7     1d..4   38us : update_curr (put_prev_task_fair)
-[...]
-ksoftirq-7     1d..5   47us : _spin_trylock (tracing_record_cmdline)
-ksoftirq-7     1d..5   48us : add_preempt_count (_spin_trylock)
-ksoftirq-7     1d..6   49us : _spin_unlock (tracing_record_cmdline)
-ksoftirq-7     1d..6   49us : sub_preempt_count (_spin_unlock)
-ksoftirq-7     1d..4   50us : schedule (__cond_resched)
-
-The interrupt went off while running ksoftirqd. This task runs at
-SCHED_OTHER. Why did not we see the 'N' set early? This may be
-a harmless bug with x86_32 and 4K stacks. On x86_32 with 4K stacks
-configured, the interrupt and softirq run with their own stack.
-Some information is held on the top of the task's stack (need_resched
-and preempt_count are both stored there). The setting of the NEED_RESCHED
-bit is done directly to the task's stack, but the reading of the
-NEED_RESCHED is done by looking at the current stack, which in this case
-is the stack for the hard interrupt. This hides the fact that NEED_RESCHED
-has been set. We do not see the 'N' until we switch back to the task's
-assigned stack.
-
-function
---------
-
-This tracer is the function tracer. Enabling the function tracer
-can be done from the debug file system. Make sure the ftrace_enabled is
-set; otherwise this tracer is a nop.
-
- # sysctl kernel.ftrace_enabled=1
- # echo function > /debug/tracing/current_tracer
- # echo 1 > /debug/tracing/tracing_enabled
- # usleep 1
- # echo 0 > /debug/tracing/tracing_enabled
- # cat /debug/tracing/trace
-# tracer: function
-#
-#           TASK-PID   CPU#    TIMESTAMP  FUNCTION
-#              | |      |          |         |
-            bash-4003  [00]   123.638713: finish_task_switch <-schedule
-            bash-4003  [00]   123.638714: _spin_unlock_irq <-finish_task_switch
-            bash-4003  [00]   123.638714: sub_preempt_count <-_spin_unlock_irq
-            bash-4003  [00]   123.638715: hrtick_set <-schedule
-            bash-4003  [00]   123.638715: _spin_lock_irqsave <-hrtick_set
-            bash-4003  [00]   123.638716: add_preempt_count <-_spin_lock_irqsave
-            bash-4003  [00]   123.638716: _spin_unlock_irqrestore <-hrtick_set
-            bash-4003  [00]   123.638717: sub_preempt_count <-_spin_unlock_irqrestore
-            bash-4003  [00]   123.638717: hrtick_clear <-hrtick_set
-            bash-4003  [00]   123.638718: sub_preempt_count <-schedule
-            bash-4003  [00]   123.638718: sub_preempt_count <-preempt_schedule
-            bash-4003  [00]   123.638719: wait_for_completion <-__stop_machine_run
-            bash-4003  [00]   123.638719: wait_for_common <-wait_for_completion
-            bash-4003  [00]   123.638720: _spin_lock_irq <-wait_for_common
-            bash-4003  [00]   123.638720: add_preempt_count <-_spin_lock_irq
-[...]
-
-
-Note: function tracer uses ring buffers to store the above entries.
-The newest data may overwrite the oldest data. Sometimes using echo to
-stop the trace is not sufficient because the tracing could have overwritten
-the data that you wanted to record. For this reason, it is sometimes better to
-disable tracing directly from a program. This allows you to stop the
-tracing at the point that you hit the part that you are interested in.
-To disable the tracing directly from a C program, something like following
-code snippet can be used:
-
-int trace_fd;
-[...]
-int main(int argc, char *argv[]) {
-	[...]
-	trace_fd = open("/debug/tracing/tracing_enabled", O_WRONLY);
-	[...]
-	if (condition_hit()) {
-		write(trace_fd, "0", 1);
-	}
-	[...]
-}
-
-Note: Here we hard coded the path name. The debugfs mount is not
-guaranteed to be at /debug (and is more commonly at /sys/kernel/debug).
-For simple one time traces, the above is sufficent. For anything else,
-a search through /proc/mounts may be needed to find where the debugfs
-file-system is mounted.
-
-
-Single thread tracing
----------------------
-
-By writing into /debug/tracing/set_ftrace_pid you can trace a
-single thread. For example:
-
-# cat /debug/tracing/set_ftrace_pid
-no pid
-# echo 3111 > /debug/tracing/set_ftrace_pid
-# cat /debug/tracing/set_ftrace_pid
-3111
-# echo function > /debug/tracing/current_tracer
-# cat /debug/tracing/trace | head
- # tracer: function
- #
- #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
- #              | |       |          |         |
-     yum-updatesd-3111  [003]  1637.254676: finish_task_switch <-thread_return
-     yum-updatesd-3111  [003]  1637.254681: hrtimer_cancel <-schedule_hrtimeout_range
-     yum-updatesd-3111  [003]  1637.254682: hrtimer_try_to_cancel <-hrtimer_cancel
-     yum-updatesd-3111  [003]  1637.254683: lock_hrtimer_base <-hrtimer_try_to_cancel
-     yum-updatesd-3111  [003]  1637.254685: fget_light <-do_sys_poll
-     yum-updatesd-3111  [003]  1637.254686: pipe_poll <-do_sys_poll
-# echo -1 > /debug/tracing/set_ftrace_pid
-# cat /debug/tracing/trace |head
- # tracer: function
- #
- #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
- #              | |       |          |         |
- ##### CPU 3 buffer started ####
-     yum-updatesd-3111  [003]  1701.957688: free_poll_entry <-poll_freewait
-     yum-updatesd-3111  [003]  1701.957689: remove_wait_queue <-free_poll_entry
-     yum-updatesd-3111  [003]  1701.957691: fput <-free_poll_entry
-     yum-updatesd-3111  [003]  1701.957692: audit_syscall_exit <-sysret_audit
-     yum-updatesd-3111  [003]  1701.957693: path_put <-audit_syscall_exit
-
-If you want to trace a function when executing, you could use
-something like this simple program:
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <unistd.h>
-
-int main (int argc, char **argv)
-{
-        if (argc < 1)
-                exit(-1);
-
-        if (fork() > 0) {
-                int fd, ffd;
-                char line[64];
-                int s;
-
-                ffd = open("/debug/tracing/current_tracer", O_WRONLY);
-                if (ffd < 0)
-                        exit(-1);
-                write(ffd, "nop", 3);
-
-                fd = open("/debug/tracing/set_ftrace_pid", O_WRONLY);
-                s = sprintf(line, "%d\n", getpid());
-                write(fd, line, s);
-
-                write(ffd, "function", 8);
-
-                close(fd);
-                close(ffd);
-
-                execvp(argv[1], argv+1);
-        }
-
-        return 0;
-}
-
-dynamic ftrace
---------------
-
-If CONFIG_DYNAMIC_FTRACE is set, the system will run with
-virtually no overhead when function tracing is disabled. The way
-this works is the mcount function call (placed at the start of
-every kernel function, produced by the -pg switch in gcc), starts
-of pointing to a simple return. (Enabling FTRACE will include the
--pg switch in the compiling of the kernel.)
-
-At compile time every C file object is run through the
-recordmcount.pl script (located in the scripts directory). This
-script will process the C object using objdump to find all the
-locations in the .text section that call mcount. (Note, only
-the .text section is processed, since processing other sections
-like .init.text may cause races due to those sections being freed).
-
-A new section called "__mcount_loc" is created that holds references
-to all the mcount call sites in the .text section. This section is
-compiled back into the original object. The final linker will add
-all these references into a single table.
-
-On boot up, before SMP is initialized, the dynamic ftrace code
-scans this table and updates all the locations into nops. It also
-records the locations, which are added to the available_filter_functions
-list.  Modules are processed as they are loaded and before they are
-executed.  When a module is unloaded, it also removes its functions from
-the ftrace function list. This is automatic in the module unload
-code, and the module author does not need to worry about it.
-
-When tracing is enabled, kstop_machine is called to prevent races
-with the CPUS executing code being modified (which can cause the
-CPU to do undesireable things), and the nops are patched back
-to calls. But this time, they do not call mcount (which is just
-a function stub). They now call into the ftrace infrastructure.
-
-One special side-effect to the recording of the functions being
-traced is that we can now selectively choose which functions we
-wish to trace and which ones we want the mcount calls to remain as
-nops.
-
-Two files are used, one for enabling and one for disabling the tracing
-of specified functions. They are:
-
-  set_ftrace_filter
-
-and
-
-  set_ftrace_notrace
-
-A list of available functions that you can add to these files is listed
-in:
-
-   available_filter_functions
-
- # cat /debug/tracing/available_filter_functions
-put_prev_task_idle
-kmem_cache_create
-pick_next_task_rt
-get_online_cpus
-pick_next_task_fair
-mutex_lock
-[...]
-
-If I am only interested in sys_nanosleep and hrtimer_interrupt:
-
- # echo sys_nanosleep hrtimer_interrupt \
-		> /debug/tracing/set_ftrace_filter
- # echo ftrace > /debug/tracing/current_tracer
- # echo 1 > /debug/tracing/tracing_enabled
- # usleep 1
- # echo 0 > /debug/tracing/tracing_enabled
- # cat /debug/tracing/trace
-# tracer: ftrace
-#
-#           TASK-PID   CPU#    TIMESTAMP  FUNCTION
-#              | |      |          |         |
-          usleep-4134  [00]  1317.070017: hrtimer_interrupt <-smp_apic_timer_interrupt
-          usleep-4134  [00]  1317.070111: sys_nanosleep <-syscall_call
-          <idle>-0     [00]  1317.070115: hrtimer_interrupt <-smp_apic_timer_interrupt
-
-To see which functions are being traced, you can cat the file:
-
- # cat /debug/tracing/set_ftrace_filter
-hrtimer_interrupt
-sys_nanosleep
-
-
-Perhaps this is not enough. The filters also allow simple wild cards.
-Only the following are currently available
-
-  <match>*  - will match functions that begin with <match>
-  *<match>  - will match functions that end with <match>
-  *<match>* - will match functions that have <match> in it
-
-These are the only wild cards which are supported.
-
-  <match>*<match> will not work.
-
-Note: It is better to use quotes to enclose the wild cards, otherwise
-  the shell may expand the parameters into names of files in the local
-  directory.
-
- # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter
-
-Produces:
-
-# tracer: ftrace
-#
-#           TASK-PID   CPU#    TIMESTAMP  FUNCTION
-#              | |      |          |         |
-            bash-4003  [00]  1480.611794: hrtimer_init <-copy_process
-            bash-4003  [00]  1480.611941: hrtimer_start <-hrtick_set
-            bash-4003  [00]  1480.611956: hrtimer_cancel <-hrtick_clear
-            bash-4003  [00]  1480.611956: hrtimer_try_to_cancel <-hrtimer_cancel
-          <idle>-0     [00]  1480.612019: hrtimer_get_next_event <-get_next_timer_interrupt
-          <idle>-0     [00]  1480.612025: hrtimer_get_next_event <-get_next_timer_interrupt
-          <idle>-0     [00]  1480.612032: hrtimer_get_next_event <-get_next_timer_interrupt
-          <idle>-0     [00]  1480.612037: hrtimer_get_next_event <-get_next_timer_interrupt
-          <idle>-0     [00]  1480.612382: hrtimer_get_next_event <-get_next_timer_interrupt
-
-
-Notice that we lost the sys_nanosleep.
-
- # cat /debug/tracing/set_ftrace_filter
-hrtimer_run_queues
-hrtimer_run_pending
-hrtimer_init
-hrtimer_cancel
-hrtimer_try_to_cancel
-hrtimer_forward
-hrtimer_start
-hrtimer_reprogram
-hrtimer_force_reprogram
-hrtimer_get_next_event
-hrtimer_interrupt
-hrtimer_nanosleep
-hrtimer_wakeup
-hrtimer_get_remaining
-hrtimer_get_res
-hrtimer_init_sleeper
-
-
-This is because the '>' and '>>' act just like they do in bash.
-To rewrite the filters, use '>'
-To append to the filters, use '>>'
-
-To clear out a filter so that all functions will be recorded again:
-
- # echo > /debug/tracing/set_ftrace_filter
- # cat /debug/tracing/set_ftrace_filter
- #
-
-Again, now we want to append.
-
- # echo sys_nanosleep > /debug/tracing/set_ftrace_filter
- # cat /debug/tracing/set_ftrace_filter
-sys_nanosleep
- # echo 'hrtimer_*' >> /debug/tracing/set_ftrace_filter
- # cat /debug/tracing/set_ftrace_filter
-hrtimer_run_queues
-hrtimer_run_pending
-hrtimer_init
-hrtimer_cancel
-hrtimer_try_to_cancel
-hrtimer_forward
-hrtimer_start
-hrtimer_reprogram
-hrtimer_force_reprogram
-hrtimer_get_next_event
-hrtimer_interrupt
-sys_nanosleep
-hrtimer_nanosleep
-hrtimer_wakeup
-hrtimer_get_remaining
-hrtimer_get_res
-hrtimer_init_sleeper
-
-
-The set_ftrace_notrace prevents those functions from being traced.
-
- # echo '*preempt*' '*lock*' > /debug/tracing/set_ftrace_notrace
-
-Produces:
-
-# tracer: ftrace
-#
-#           TASK-PID   CPU#    TIMESTAMP  FUNCTION
-#              | |      |          |         |
-            bash-4043  [01]   115.281644: finish_task_switch <-schedule
-            bash-4043  [01]   115.281645: hrtick_set <-schedule
-            bash-4043  [01]   115.281645: hrtick_clear <-hrtick_set
-            bash-4043  [01]   115.281646: wait_for_completion <-__stop_machine_run
-            bash-4043  [01]   115.281647: wait_for_common <-wait_for_completion
-            bash-4043  [01]   115.281647: kthread_stop <-stop_machine_run
-            bash-4043  [01]   115.281648: init_waitqueue_head <-kthread_stop
-            bash-4043  [01]   115.281648: wake_up_process <-kthread_stop
-            bash-4043  [01]   115.281649: try_to_wake_up <-wake_up_process
-
-We can see that there's no more lock or preempt tracing.
-
-trace_pipe
-----------
-
-The trace_pipe outputs the same content as the trace file, but the effect
-on the tracing is different. Every read from trace_pipe is consumed.
-This means that subsequent reads will be different. The trace
-is live.
-
- # echo function > /debug/tracing/current_tracer
- # cat /debug/tracing/trace_pipe > /tmp/trace.out &
-[1] 4153
- # echo 1 > /debug/tracing/tracing_enabled
- # usleep 1
- # echo 0 > /debug/tracing/tracing_enabled
- # cat /debug/tracing/trace
-# tracer: function
-#
-#           TASK-PID   CPU#    TIMESTAMP  FUNCTION
-#              | |      |          |         |
-
- #
- # cat /tmp/trace.out
-            bash-4043  [00] 41.267106: finish_task_switch <-schedule
-            bash-4043  [00] 41.267106: hrtick_set <-schedule
-            bash-4043  [00] 41.267107: hrtick_clear <-hrtick_set
-            bash-4043  [00] 41.267108: wait_for_completion <-__stop_machine_run
-            bash-4043  [00] 41.267108: wait_for_common <-wait_for_completion
-            bash-4043  [00] 41.267109: kthread_stop <-stop_machine_run
-            bash-4043  [00] 41.267109: init_waitqueue_head <-kthread_stop
-            bash-4043  [00] 41.267110: wake_up_process <-kthread_stop
-            bash-4043  [00] 41.267110: try_to_wake_up <-wake_up_process
-            bash-4043  [00] 41.267111: select_task_rq_rt <-try_to_wake_up
-
-
-Note, reading the trace_pipe file will block until more input is added.
-By changing the tracer, trace_pipe will issue an EOF. We needed
-to set the function tracer _before_ we "cat" the trace_pipe file.
-
-
-trace entries
--------------
-
-Having too much or not enough data can be troublesome in diagnosing
-an issue in the kernel. The file buffer_size_kb is used to modify
-the size of the internal trace buffers. The number listed
-is the number of entries that can be recorded per CPU. To know
-the full size, multiply the number of possible CPUS with the
-number of entries.
-
- # cat /debug/tracing/buffer_size_kb
-1408 (units kilobytes)
-
-Note, to modify this, you must have tracing completely disabled. To do that,
-echo "nop" into the current_tracer. If the current_tracer is not set
-to "nop", an EINVAL error will be returned.
-
- # echo nop > /debug/tracing/current_tracer
- # echo 10000 > /debug/tracing/buffer_size_kb
- # cat /debug/tracing/buffer_size_kb
-10000 (units kilobytes)
-
-The number of pages which will be allocated is limited to a percentage
-of available memory. Allocating too much will produce an error.
-
- # echo 1000000000000 > /debug/tracing/buffer_size_kb
--bash: echo: write error: Cannot allocate memory
- # cat /debug/tracing/buffer_size_kb
-85
-

Documentation/gpio.txt

@@ -123,7 +123,10 @@ platform-specific implementation issue.
 
 Using GPIOs
 -----------
-One of the first things to do with a GPIO, often in board setup code when
+The first thing a system should do with a GPIO is allocate it, using
+the gpio_request() call; see later.
+
+One of the next things to do with a GPIO, often in board setup code when
 setting up a platform_device using the GPIO, is mark its direction:
 
 	/* set as input or output, returning 0 or negative errno */
@@ -141,8 +144,8 @@ This helps avoid signal glitching during system startup.
 
 For compatibility with legacy interfaces to GPIOs, setting the direction
 of a GPIO implicitly requests that GPIO (see below) if it has not been
-requested already.  That compatibility may be removed in the future;
-explicitly requesting GPIOs is strongly preferred.
+requested already.  That compatibility is being removed from the optional
+gpiolib framework.
 
 Setting the direction can fail if the GPIO number is invalid, or when
 that particular GPIO can't be used in that mode.  It's generally a bad
@@ -195,7 +198,7 @@ This requires sleeping, which can't be done from inside IRQ handlers.
 
 Platforms that support this type of GPIO distinguish them from other GPIOs
 by returning nonzero from this call (which requires a valid GPIO number,
-either explicitly or implicitly requested):
+which should have been previously allocated with gpio_request):
 
 	int gpio_cansleep(unsigned gpio);
 
@@ -212,10 +215,9 @@ for GPIOs that can't be accessed from IRQ handlers, these calls act the
 same as the spinlock-safe calls.
 
 
-Claiming and Releasing GPIOs (OPTIONAL)
----------------------------------------
+Claiming and Releasing GPIOs
+----------------------------
 To help catch system configuration errors, two calls are defined.
-However, many platforms don't currently support this mechanism.
 
 	/* request GPIO, returning 0 or negative errno.
 	 * non-null labels may be useful for diagnostics.
@@ -244,13 +246,6 @@ Some platforms may also use knowledge about what GPIOs are active for
 power management, such as by powering down unused chip sectors and, more
 easily, gating off unused clocks.
 
-These two calls are optional because not not all current Linux platforms
-offer such functionality in their GPIO support; a valid implementation
-could return success for all gpio_request() calls.  Unlike the other calls,
-the state they represent doesn't normally match anything from a hardware
-register; it's just a software bitmap which clearly is not necessary for
-correct operation of hardware or (bug free) drivers.
-
 Note that requesting a GPIO does NOT cause it to be configured in any
 way; it just marks that GPIO as in use.  Separate code must handle any
 pin setup (e.g. controlling which pin the GPIO uses, pullup/pulldown).

Documentation/hwmon/ds1621

@@ -49,12 +49,9 @@ of up to +/- 0.5 degrees even when compared against precise temperature
 readings. Be sure to have a high vs. low temperature limit gap of al least
 1.0 degree Celsius to avoid Tout "bouncing", though!
 
-As for alarms, you can read the alarm status of the DS1621 via the 'alarms'
-/sys file interface. The result consists mainly of bit 6 and 5 of the
-configuration register of the chip; bit 6 (0x40 or 64) is the high alarm
-bit and bit 5 (0x20 or 32) the low one. These bits are set when the high or
-low limits are met or exceeded and are reset by the module as soon as the
-respective temperature ranges are left.
+The alarm bits are set when the high or low limits are met or exceeded and
+are reset by the module as soon as the respective temperature ranges are
+left.
 
 The alarm registers are in no way suitable to find out about the actual
 status of Tout. They will only tell you about its history, whether or not
@@ -64,45 +61,3 @@ with neither of the alarms set.
 
 Temperature conversion of the DS1621 takes up to 1000ms; internal access to
 non-volatile registers may last for 10ms or below.
-
-High Accuracy Temperature Reading
----------------------------------
-
-As said before, the temperature issued via the 9-bit i2c-bus data is
-somewhat arbitrary. Internally, the temperature conversion is of a
-different kind that is explained (not so...) well in the DS1621 data sheet.
-To cut the long story short: Inside the DS1621 there are two oscillators,
-both of them biassed by a temperature coefficient.
-
-Higher resolution of the temperature reading can be achieved using the
-internal projection, which means taking account of REG_COUNT and REG_SLOPE
-(the driver manages them):
-
-Taken from Dallas Semiconductors App Note 068: 'Increasing Temperature
-Resolution on the DS1620' and App Note 105: 'High Resolution Temperature
-Measurement with Dallas Direct-to-Digital Temperature Sensors'
-
-- Read the 9-bit temperature and strip the LSB (Truncate the .5 degs)
-- The resulting value is TEMP_READ.
-- Then, read REG_COUNT.
-- And then, REG_SLOPE.
-
-      TEMP = TEMP_READ - 0.25 + ((REG_SLOPE - REG_COUNT) / REG_SLOPE)
-
-Note that this is what the DONE bit in the DS1621 configuration register is
-good for: Internally, one temperature conversion takes up to 1000ms. Before
-that conversion is complete you will not be able to read valid things out
-of REG_COUNT and REG_SLOPE. The DONE bit, as you may have guessed by now,
-tells you whether the conversion is complete ("done", in plain English) and
-thus, whether the values you read are good or not.
-
-The DS1621 has two modes of operation: "Continuous" conversion, which can
-be understood as the default stand-alone mode where the chip gets the
-temperature and controls external devices via its Tout pin or tells other
-i2c's about it if they care. The other mode is called "1SHOT", that means
-that it only figures out about the temperature when it is explicitly told
-to do so; this can be seen as power saving mode.
-
-Now if you want to read REG_COUNT and REG_SLOPE, you have to either stop
-the continuous conversions until the contents of these registers are valid,
-or, in 1SHOT mode, you have to have one conversion made.

Documentation/hwmon/g760a

@@ -0,0 +1,36 @@
+Kernel driver g760a
+===================
+
+Supported chips:
+  * Global Mixed-mode Technology Inc. G760A
+    Prefix: 'g760a'
+    Datasheet: Publicly available at the GMT website
+      http://www.gmt.com.tw/datasheet/g760a.pdf
+
+Author: Herbert Valerio Riedel <hvr@gnu.org>
+
+Description
+-----------
+
+The GMT G760A Fan Speed PWM Controller is connected directly to a fan
+and performs closed-loop control of the fan speed.
+
+The fan speed is programmed by setting the period via 'pwm1' of two
+consecutive speed pulses. The period is defined in terms of clock
+cycle counts of an assumed 32kHz clock source.
+
+Setting a period of 0 stops the fan; setting the period to 255 sets
+fan to maximum speed.
+
+The measured fan rotation speed returned via 'fan1_input' is derived
+from the measured speed pulse period by assuming again a 32kHz clock
+source and a 2 pulse-per-revolution fan.
+
+The 'alarms' file provides access to the two alarm bits provided by
+the G760A chip's status register: Bit 0 is set when the actual fan
+speed differs more than 20% with respect to the programmed fan speed;
+bit 1 is set when fan speed is below 1920 RPM.
+
+The g760a driver will not update its values more frequently than every
+other second; reading them more often will do no harm, but will return
+'old' values.

Documentation/hwmon/lis3lv02d

@@ -1,11 +1,11 @@
 Kernel driver lis3lv02d
-==================
+=======================
 
 Supported chips:
 
   * STMicroelectronics LIS3LV02DL and LIS3LV02DQ
 
-Author:
+Authors:
         Yan Burman <burman.yan@gmail.com>
 	Eric Piel <eric.piel@tremplin-utc.net>
 
@@ -15,7 +15,7 @@ Description
 
 This driver provides support for the accelerometer found in various HP
 laptops sporting the feature officially called "HP Mobile Data
-Protection System 3D" or "HP 3D DriveGuard". It detect automatically
+Protection System 3D" or "HP 3D DriveGuard". It detects automatically
 laptops with this sensor. Known models (for now the HP 2133, nc6420,
 nc2510, nc8510, nc84x0, nw9440 and nx9420) will have their axis
 automatically oriented on standard way (eg: you can directly play
@@ -27,7 +27,7 @@ position - 3D position that the accelerometer reports. Format: "(x,y,z)"
 calibrate - read: values (x, y, z) that are used as the base for input
 		  class device operation.
             write: forces the base to be recalibrated with the current
-		  position.
+		   position.
 rate - reports the sampling rate of the accelerometer device in HZ
 
 This driver also provides an absolute input class device, allowing
@@ -48,7 +48,7 @@ For better compatibility between the various laptops. The values reported by
 the accelerometer are converted into a "standard" organisation of the axes
 (aka "can play neverball out of the box"):
  * When the laptop is horizontal the position reported is about 0 for X and Y
-and a positive value for Z
+	and a positive value for Z
  * If the left side is elevated, X increases (becomes positive)
  * If the front side (where the touchpad is) is elevated, Y decreases
 	(becomes negative)
@@ -59,3 +59,13 @@ email to the authors to add it to the database.  When reporting a new
 laptop, please include the output of "dmidecode" plus the value of
 /sys/devices/platform/lis3lv02d/position in these four cases.
 
+Q&A
+---
+
+Q: How do I safely simulate freefall? I have an HP "portable
+workstation" which has about 3.5kg and a plastic case, so letting it
+fall to the ground is out of question...
+
+A: The sensor is pretty sensitive, so your hands can do it. Lift it
+into free space, follow the fall with your hands for like 10
+centimeters. That should be enough to trigger the detection.

Documentation/hwmon/ltc4215

@@ -0,0 +1,50 @@
+Kernel driver ltc4215
+=====================
+
+Supported chips:
+  * Linear Technology LTC4215
+    Prefix: 'ltc4215'
+    Addresses scanned: 0x44
+    Datasheet:
+        http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1163,P17572,D12697
+
+Author: Ira W. Snyder <iws@ovro.caltech.edu>
+
+
+Description
+-----------
+
+The LTC4215 controller allows a board to be safely inserted and removed
+from a live backplane.
+
+
+Usage Notes
+-----------
+
+This driver does not probe for LTC4215 devices, due to the fact that some
+of the possible addresses are unfriendly to probing. You will need to use
+the "force" parameter to tell the driver where to find the device.
+
+Example: the following will load the driver for an LTC4215 at address 0x44
+on I2C bus #0:
+$ modprobe ltc4215 force=0,0x44
+
+
+Sysfs entries
+-------------
+
+The LTC4215 has built-in limits for overvoltage, undervoltage, and
+undercurrent warnings. This makes it very likely that the reference
+circuit will be used.
+
+in1_input		input voltage
+in2_input		output voltage
+
+in1_min_alarm		input undervoltage alarm
+in1_max_alarm		input overvoltage alarm
+
+curr1_input		current
+curr1_max_alarm		overcurrent alarm
+
+power1_input		power usage
+power1_alarm		power bad alarm

Documentation/hwmon/sysfs-interface

@@ -365,6 +365,7 @@ energy[1-*]_input		Cumulative energy use
 				Unit: microJoule
 				RO
 
+
 **********
 * Alarms *
 **********
@@ -453,6 +454,27 @@ beep_mask	Bitmask for beep.
 		RW
 
 
+***********************
+* Intrusion detection *
+***********************
+
+intrusion[0-*]_alarm
+		Chassis intrusion detection
+		0: OK
+		1: intrusion detected
+		RW
+		Contrary to regular alarm flags which clear themselves
+		automatically when read, this one sticks until cleared by
+		the user. This is done by writing 0 to the file. Writing
+		other values is unsupported.
+
+intrusion[0-*]_beep
+		Chassis intrusion beep
+		0: disable
+		1: enable
+		RW
+
+
 sysfs attribute writes interpretation
 -------------------------------------
 

Documentation/hwmon/w83627ehf

@@ -2,30 +2,40 @@ Kernel driver w83627ehf
 =======================
 
 Supported chips:
-  * Winbond W83627EHF/EHG/DHG (ISA access ONLY)
+  * Winbond W83627EHF/EHG (ISA access ONLY)
     Prefix: 'w83627ehf'
     Addresses scanned: ISA address retrieved from Super I/O registers
     Datasheet:
-        http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83627EHF_%20W83627EHGb.pdf
-        DHG datasheet confidential.
+        http://www.nuvoton.com.tw/NR/rdonlyres/A6A258F0-F0C9-4F97-81C0-C4D29E7E943E/0/W83627EHF.pdf
+  * Winbond W83627DHG
+    Prefix: 'w83627dhg'
+    Addresses scanned: ISA address retrieved from Super I/O registers
+    Datasheet:
+        http://www.nuvoton.com.tw/NR/rdonlyres/7885623D-A487-4CF9-A47F-30C5F73D6FE6/0/W83627DHG.pdf
+  * Winbond W83667HG
+    Prefix: 'w83667hg'
+    Addresses scanned: ISA address retrieved from Super I/O registers
+    Datasheet: not available
 
 Authors:
         Jean Delvare <khali@linux-fr.org>
         Yuan Mu (Winbond)
         Rudolf Marek <r.marek@assembler.cz>
         David Hubbard <david.c.hubbard@gmail.com>
+        Gong Jun <JGong@nuvoton.com>
 
 Description
 -----------
 
-This driver implements support for the Winbond W83627EHF, W83627EHG, and
-W83627DHG super I/O chips. We will refer to them collectively as Winbond chips.
+This driver implements support for the Winbond W83627EHF, W83627EHG,
+W83627DHG and W83667HG super I/O chips. We will refer to them collectively
+as Winbond chips.
 
 The chips implement three temperature sensors, five fan rotation
 speed sensors, ten analog voltage sensors (only nine for the 627DHG), one
-VID (6 pins for the 627EHF/EHG, 8 pins for the 627DHG), alarms with beep
-warnings (control unimplemented), and some automatic fan regulation
-strategies (plus manual fan control mode).
+VID (6 pins for the 627EHF/EHG, 8 pins for the 627DHG and 667HG), alarms
+with beep warnings (control unimplemented), and some automatic fan
+regulation strategies (plus manual fan control mode).
 
 Temperatures are measured in degrees Celsius and measurement resolution is 1
 degC for temp1 and 0.5 degC for temp2 and temp3. An alarm is triggered when
@@ -54,7 +64,8 @@ follows:
 temp1 -> pwm1
 temp2 -> pwm2
 temp3 -> pwm3
-prog  -> pwm4 (the programmable setting is not supported by the driver)
+prog  -> pwm4 (not on 667HG; the programmable setting is not supported by
+	       the driver)
 
 /sys files
 ----------

Documentation/ia64/kvm.txt

@@ -42,7 +42,7 @@ Note: For step 2, please make sure that host page size == TARGET_PAGE_SIZE of qe
 		hg clone http://xenbits.xensource.com/ext/efi-vfirmware.hg
 	    you can get the firmware's binary in the directory of efi-vfirmware.hg/binaries.
 
-	(3) Rename the firware you owned to Flash.fd, and copy it to /usr/local/share/qemu
+	(3) Rename the firmware you owned to Flash.fd, and copy it to /usr/local/share/qemu
 
 4. Boot up Linux or Windows guests:
 	4.1 Create or install a image for guest boot. If you have xen experience, it should be easy.

Documentation/infiniband/ipoib.txt

@@ -24,6 +24,49 @@ Partitions and P_Keys
   The P_Key for any interface is given by the "pkey" file, and the
   main interface for a subinterface is in "parent."
 
+Datagram vs Connected modes
+
+  The IPoIB driver supports two modes of operation: datagram and
+  connected.  The mode is set and read through an interface's
+  /sys/class/net/<intf name>/mode file.
+
+  In datagram mode, the IB UD (Unreliable Datagram) transport is used
+  and so the interface MTU has is equal to the IB L2 MTU minus the
+  IPoIB encapsulation header (4 bytes).  For example, in a typical IB
+  fabric with a 2K MTU, the IPoIB MTU will be 2048 - 4 = 2044 bytes.
+
+  In connected mode, the IB RC (Reliable Connected) transport is used.
+  Connected mode is to takes advantage of the connected nature of the
+  IB transport and allows an MTU up to the maximal IP packet size of
+  64K, which reduces the number of IP packets needed for handling
+  large UDP datagrams, TCP segments, etc and increases the performance
+  for large messages.
+
+  In connected mode, the interface's UD QP is still used for multicast
+  and communication with peers that don't support connected mode. In
+  this case, RX emulation of ICMP PMTU packets is used to cause the
+  networking stack to use the smaller UD MTU for these neighbours.
+
+Stateless offloads
+
+  If the IB HW supports IPoIB stateless offloads, IPoIB advertises
+  TCP/IP checksum and/or Large Send (LSO) offloading capability to the
+  network stack.
+
+  Large Receive (LRO) offloading is also implemented and may be turned
+  on/off using ethtool calls.  Currently LRO is supported only for
+  checksum offload capable devices.
+
+  Stateless offloads are supported only in datagram mode.  
+
+Interrupt moderation
+
+  If the underlying IB device supports CQ event moderation, one can
+  use ethtool to set interrupt mitigation parameters and thus reduce
+  the overhead incurred by handling interrupts.  The main code path of
+  IPoIB doesn't use events for TX completion signaling so only RX
+  moderation is supported.
+
 Debugging Information
 
   By compiling the IPoIB driver with CONFIG_INFINIBAND_IPOIB_DEBUG set
@@ -55,3 +98,5 @@ References
     http://ietf.org/rfc/rfc4391.txt 
   IP over InfiniBand (IPoIB) Architecture (RFC 4392)
     http://ietf.org/rfc/rfc4392.txt 
+  IP over InfiniBand: Connected Mode (RFC 4755)
+    http://ietf.org/rfc/rfc4755.txt

Documentation/input/bcm5974.txt

@@ -0,0 +1,65 @@
+BCM5974 Driver (bcm5974)
+------------------------
+	Copyright (C) 2008-2009	Henrik Rydberg <rydberg@euromail.se>
+
+The USB initialization and package decoding was made by Scott Shawcroft as
+part of the touchd user-space driver project:
+	Copyright (C) 2008	Scott Shawcroft (scott.shawcroft@gmail.com)
+
+The BCM5974 driver is based on the appletouch driver:
+	Copyright (C) 2001-2004	Greg Kroah-Hartman (greg@kroah.com)
+	Copyright (C) 2005	Johannes Berg (johannes@sipsolutions.net)
+	Copyright (C) 2005	Stelian Pop (stelian@popies.net)
+	Copyright (C) 2005	Frank Arnold (frank@scirocco-5v-turbo.de)
+	Copyright (C) 2005	Peter Osterlund (petero2@telia.com)
+	Copyright (C) 2005	Michael Hanselmann (linux-kernel@hansmi.ch)
+	Copyright (C) 2006	Nicolas Boichat (nicolas@boichat.ch)
+
+This driver adds support for the multi-touch trackpad on the new Apple
+Macbook Air and Macbook Pro laptops. It replaces the appletouch driver on
+those computers, and integrates well with the synaptics driver of the Xorg
+system.
+
+Known to work on Macbook Air, Macbook Pro Penryn and the new unibody
+Macbook 5 and Macbook Pro 5.
+
+Usage
+-----
+
+The driver loads automatically for the supported usb device ids, and
+becomes available both as an event device (/dev/input/event*) and as a
+mouse via the mousedev driver (/dev/input/mice).
+
+USB Race
+--------
+
+The Apple multi-touch trackpads report both mouse and keyboard events via
+different interfaces of the same usb device. This creates a race condition
+with the HID driver, which, if not told otherwise, will find the standard
+HID mouse and keyboard, and claim the whole device. To remedy, the usb
+product id must be listed in the mouse_ignore list of the hid driver.
+
+Debug output
+------------
+
+To ease the development for new hardware version, verbose packet output can
+be switched on with the debug kernel module parameter. The range [1-9]
+yields different levels of verbosity. Example (as root):
+
+echo -n 9 > /sys/module/bcm5974/parameters/debug
+
+tail -f /var/log/debug
+
+echo -n 0 > /sys/module/bcm5974/parameters/debug
+
+Trivia
+------
+
+The driver was developed at the ubuntu forums in June 2008 [1], and now has
+a more permanent home at bitmath.org [2].
+
+Links
+-----
+
+[1] http://ubuntuforums.org/showthread.php?t=840040
+[2] http://http://bitmath.org/code/

Documentation/input/multi-touch-protocol.txt

@@ -0,0 +1,140 @@
+Multi-touch (MT) Protocol
+-------------------------
+	Copyright (C) 2009	Henrik Rydberg <rydberg@euromail.se>
+
+
+Introduction
+------------
+
+In order to utilize the full power of the new multi-touch devices, a way to
+report detailed finger data to user space is needed. This document
+describes the multi-touch (MT) protocol which allows kernel drivers to
+report details for an arbitrary number of fingers.
+
+
+Usage
+-----
+
+Anonymous finger details are sent sequentially as separate packets of ABS
+events. Only the ABS_MT events are recognized as part of a finger
+packet. The end of a packet is marked by calling the input_mt_sync()
+function, which generates a SYN_MT_REPORT event. The end of multi-touch
+transfer is marked by calling the usual input_sync() function.
+
+A set of ABS_MT events with the desired properties is defined. The events
+are divided into categories, to allow for partial implementation.  The
+minimum set consists of ABS_MT_TOUCH_MAJOR, ABS_MT_POSITION_X and
+ABS_MT_POSITION_Y, which allows for multiple fingers to be tracked.  If the
+device supports it, the ABS_MT_WIDTH_MAJOR may be used to provide the size
+of the approaching finger. Anisotropy and direction may be specified with
+ABS_MT_TOUCH_MINOR, ABS_MT_WIDTH_MINOR and ABS_MT_ORIENTATION. Devices with
+more granular information may specify general shapes as blobs, i.e., as a
+sequence of rectangular shapes grouped together by an
+ABS_MT_BLOB_ID. Finally, the ABS_MT_TOOL_TYPE may be used to specify
+whether the touching tool is a finger or a pen or something else.
+
+
+Event Semantics
+---------------
+
+The word "contact" is used to describe a tool which is in direct contact
+with the surface. A finger, a pen or a rubber all classify as contacts.
+
+ABS_MT_TOUCH_MAJOR
+
+The length of the major axis of the contact. The length should be given in
+surface units. If the surface has an X times Y resolution, the largest
+possible value of ABS_MT_TOUCH_MAJOR is sqrt(X^2 + Y^2), the diagonal.
+
+ABS_MT_TOUCH_MINOR
+
+The length, in surface units, of the minor axis of the contact. If the
+contact is circular, this event can be omitted.
+
+ABS_MT_WIDTH_MAJOR
+
+The length, in surface units, of the major axis of the approaching
+tool. This should be understood as the size of the tool itself. The
+orientation of the contact and the approaching tool are assumed to be the
+same.
+
+ABS_MT_WIDTH_MINOR
+
+The length, in surface units, of the minor axis of the approaching
+tool. Omit if circular.
+
+The above four values can be used to derive additional information about
+the contact. The ratio ABS_MT_TOUCH_MAJOR / ABS_MT_WIDTH_MAJOR approximates
+the notion of pressure. The fingers of the hand and the palm all have
+different characteristic widths [1].
+
+ABS_MT_ORIENTATION
+
+The orientation of the ellipse. The value should describe half a revolution
+clockwise around the touch center. The scale of the value is arbitrary, but
+zero should be returned for an ellipse aligned along the Y axis of the
+surface. As an example, an index finger placed straight onto the axis could
+return zero orientation, something negative when twisted to the left, and
+something positive when twisted to the right. This value can be omitted if
+the touching object is circular, or if the information is not available in
+the kernel driver.
+
+ABS_MT_POSITION_X
+
+The surface X coordinate of the center of the touching ellipse.
+
+ABS_MT_POSITION_Y
+
+The surface Y coordinate of the center of the touching ellipse.
+
+ABS_MT_TOOL_TYPE
+
+The type of approaching tool. A lot of kernel drivers cannot distinguish
+between different tool types, such as a finger or a pen. In such cases, the
+event should be omitted. The protocol currently supports MT_TOOL_FINGER and
+MT_TOOL_PEN [2].
+
+ABS_MT_BLOB_ID
+
+The BLOB_ID groups several packets together into one arbitrarily shaped
+contact. This is a low-level anonymous grouping, and should not be confused
+with the high-level contactID, explained below. Most kernel drivers will
+not have this capability, and can safely omit the event.
+
+
+Finger Tracking
+---------------
+
+The kernel driver should generate an arbitrary enumeration of the set of
+anonymous contacts currently on the surface. The order in which the packets
+appear in the event stream is not important.
+
+The process of finger tracking, i.e., to assign a unique contactID to each
+initiated contact on the surface, is left to user space; preferably the
+multi-touch X driver [3]. In that driver, the contactID stays the same and
+unique until the contact vanishes (when the finger leaves the surface). The
+problem of assigning a set of anonymous fingers to a set of identified
+fingers is a euclidian bipartite matching problem at each event update, and
+relies on a sufficiently rapid update rate.
+
+Notes
+-----
+
+In order to stay compatible with existing applications, the data
+reported in a finger packet must not be recognized as single-touch
+events. In addition, all finger data must bypass input filtering,
+since subsequent events of the same type refer to different fingers.
+
+The first kernel driver to utilize the MT protocol is the bcm5974 driver,
+where examples can be found.
+
+[1] With the extension ABS_MT_APPROACH_X and ABS_MT_APPROACH_Y, the
+difference between the contact position and the approaching tool position
+could be used to derive tilt.
+[2] The list can of course be extended.
+[3] The multi-touch X driver is currently in the prototyping stage. At the
+time of writing (April 2009), the MT protocol is not yet merged, and the
+prototype implements finger matching, basic mouse support and two-finger
+scrolling. The project aims at improving the quality of current multi-touch
+functionality available in the synaptics X driver, and in addition
+implement more advanced gestures.

Documentation/input/rotary-encoder.txt

@@ -0,0 +1,101 @@
+rotary-encoder - a generic driver for GPIO connected devices
+Daniel Mack <daniel@caiaq.de>, Feb 2009
+
+0. Function
+-----------
+
+Rotary encoders are devices which are connected to the CPU or other
+peripherals with two wires. The outputs are phase-shifted by 90 degrees
+and by triggering on falling and rising edges, the turn direction can
+be determined.
+
+The phase diagram of these two outputs look like this:
+
+                  _____       _____       _____
+                 |     |     |     |     |     |
+  Channel A  ____|     |_____|     |_____|     |____
+
+                 :  :  :  :  :  :  :  :  :  :  :  :
+            __       _____       _____       _____
+              |     |     |     |     |     |     |
+  Channel B   |_____|     |_____|     |_____|     |__
+
+                 :  :  :  :  :  :  :  :  :  :  :  :
+  Event          a  b  c  d  a  b  c  d  a  b  c  d
+
+                |<-------->|
+	          one step
+
+
+For more information, please see
+	http://en.wikipedia.org/wiki/Rotary_encoder
+
+
+1. Events / state machine
+-------------------------
+
+a) Rising edge on channel A, channel B in low state
+	This state is used to recognize a clockwise turn
+
+b) Rising edge on channel B, channel A in high state
+	When entering this state, the encoder is put into 'armed' state,
+	meaning that there it has seen half the way of a one-step transition.
+
+c) Falling edge on channel A, channel B in high state
+	This state is used to recognize a counter-clockwise turn
+
+d) Falling edge on channel B, channel A in low state
+	Parking position. If the encoder enters this state, a full transition
+	should have happend, unless it flipped back on half the way. The
+	'armed' state tells us about that.
+
+2. Platform requirements
+------------------------
+
+As there is no hardware dependent call in this driver, the platform it is
+used with must support gpiolib. Another requirement is that IRQs must be
+able to fire on both edges.
+
+
+3. Board integration
+--------------------
+
+To use this driver in your system, register a platform_device with the
+name 'rotary-encoder' and associate the IRQs and some specific platform
+data with it.
+
+struct rotary_encoder_platform_data is declared in
+include/linux/rotary-encoder.h and needs to be filled with the number of
+steps the encoder has and can carry information about externally inverted
+signals (because of used invertig buffer or other reasons).
+
+Because GPIO to IRQ mapping is platform specific, this information must
+be given in seperately to the driver. See the example below.
+
+---------<snip>---------
+
+/* board support file example */
+
+#include <linux/input.h>
+#include <linux/rotary_encoder.h>
+
+#define GPIO_ROTARY_A 1
+#define GPIO_ROTARY_B 2
+
+static struct rotary_encoder_platform_data my_rotary_encoder_info = {
+	.steps		= 24,
+	.axis		= ABS_X,
+	.gpio_a		= GPIO_ROTARY_A,
+	.gpio_b		= GPIO_ROTARY_B,
+	.inverted_a	= 0,
+	.inverted_b	= 0,
+};
+
+static struct platform_device rotary_encoder_device = {
+	.name		= "rotary-encoder",
+	.id		= 0,
+	.dev		= {
+		.platform_data = &my_rotary_encoder_info,
+	}
+};
+

Documentation/ioctl/ioctl-number.txt

@@ -122,10 +122,8 @@ Code	Seq#	Include File		Comments
 'c'	00-7F	linux/coda.h		conflict!
 'c'	80-9F	arch/s390/include/asm/chsc.h
 'd'	00-FF	linux/char/drm/drm/h	conflict!
-'d'	00-DF	linux/video_decoder.h	conflict!
 'd'	F0-FF	linux/digi1.h
 'e'	all	linux/digi1.h		conflict!
-'e'	00-1F	linux/video_encoder.h	conflict!
 'e'	00-1F	net/irda/irtty.h	conflict!
 'f'	00-1F	linux/ext2_fs.h
 'h'	00-7F				Charon filesystem

Documentation/isdn/00-INDEX

@@ -2,8 +2,14 @@
 	- this file (info on ISDN implementation for Linux)
 CREDITS
 	- list of the kind folks that brought you this stuff.
+HiSax.cert
+	- information about the ITU approval certification of the HiSax driver.
 INTERFACE
-	- description of Linklevel and Hardwarelevel ISDN interface.
+	- description of isdn4linux Link Level and Hardware Level interfaces.
+INTERFACE.fax
+	- description of the fax subinterface of isdn4linux.
+INTERFACE.CAPI
+	- description of kernel CAPI Link Level to Hardware Level interface.
 README
 	- general info on what you need and what to do for Linux ISDN.
 README.FAQ
@@ -12,6 +18,8 @@ README.audio
 	- info for running audio over ISDN.
 README.fax
 	- info for using Fax over ISDN.
+README.gigaset
+	- info on the drivers for Siemens Gigaset ISDN adapters.
 README.icn
 	- info on the ICN-ISDN-card and its driver.
 README.HiSax
@@ -37,7 +45,8 @@ README.diversion
 README.sc
 	- info on driver for Spellcaster cards.
 README.x25
-    _ info for running X.25 over ISDN.
+	- info for running X.25 over ISDN.
 README.hysdn
-        - info on driver for Hypercope active HYSDN cards
- 
+	- info on driver for Hypercope active HYSDN cards
+README.mISDN
+	- info on the Modular ISDN subsystem (mISDN).

Documentation/isdn/INTERFACE.CAPI

@@ -0,0 +1,213 @@
+Kernel CAPI Interface to Hardware Drivers
+-----------------------------------------
+
+1. Overview
+
+From the CAPI 2.0 specification:
+COMMON-ISDN-API (CAPI) is an application programming interface standard used
+to access ISDN equipment connected to basic rate interfaces (BRI) and primary
+rate interfaces (PRI).
+
+Kernel CAPI operates as a dispatching layer between CAPI applications and CAPI
+hardware drivers. Hardware drivers register ISDN devices (controllers, in CAPI
+lingo) with Kernel CAPI to indicate their readiness to provide their service
+to CAPI applications. CAPI applications also register with Kernel CAPI,
+requesting association with a CAPI device. Kernel CAPI then dispatches the
+application registration to an available device, forwarding it to the
+corresponding hardware driver. Kernel CAPI then forwards CAPI messages in both
+directions between the application and the hardware driver.
+
+Format and semantics of CAPI messages are specified in the CAPI 2.0 standard.
+This standard is freely available from http://www.capi.org.
+
+
+2. Driver and Device Registration
+
+CAPI drivers optionally register themselves with Kernel CAPI by calling the
+Kernel CAPI function register_capi_driver() with a pointer to a struct
+capi_driver. This structure must be filled with the name and revision of the
+driver, and optionally a pointer to a callback function, add_card(). The
+registration can be revoked by calling the function unregister_capi_driver()
+with a pointer to the same struct capi_driver.
+
+CAPI drivers must register each of the ISDN devices they control with Kernel
+CAPI by calling the Kernel CAPI function attach_capi_ctr() with a pointer to a
+struct capi_ctr before they can be used. This structure must be filled with
+the names of the driver and controller, and a number of callback function
+pointers which are subsequently used by Kernel CAPI for communicating with the
+driver. The registration can be revoked by calling the function
+detach_capi_ctr() with a pointer to the same struct capi_ctr.
+
+Before the device can be actually used, the driver must fill in the device
+information fields 'manu', 'version', 'profile' and 'serial' in the capi_ctr
+structure of the device, and signal its readiness by calling capi_ctr_ready().
+From then on, Kernel CAPI may call the registered callback functions for the
+device.
+
+If the device becomes unusable for any reason (shutdown, disconnect ...), the
+driver has to call capi_ctr_reseted(). This will prevent further calls to the
+callback functions by Kernel CAPI.
+
+
+3. Application Registration and Communication
+
+Kernel CAPI forwards registration requests from applications (calls to CAPI
+operation CAPI_REGISTER) to an appropriate hardware driver by calling its
+register_appl() callback function. A unique Application ID (ApplID, u16) is
+allocated by Kernel CAPI and passed to register_appl() along with the
+parameter structure provided by the application. This is analogous to the
+open() operation on regular files or character devices.
+
+After a successful return from register_appl(), CAPI messages from the
+application may be passed to the driver for the device via calls to the
+send_message() callback function. The CAPI message to send is stored in the
+data portion of an skb. Conversely, the driver may call Kernel CAPI's
+capi_ctr_handle_message() function to pass a received CAPI message to Kernel
+CAPI for forwarding to an application, specifying its ApplID.
+
+Deregistration requests (CAPI operation CAPI_RELEASE) from applications are
+forwarded as calls to the release_appl() callback function, passing the same
+ApplID as with register_appl(). After return from release_appl(), no CAPI
+messages for that application may be passed to or from the device anymore.
+
+
+4. Data Structures
+
+4.1 struct capi_driver
+
+This structure describes a Kernel CAPI driver itself. It is used in the
+register_capi_driver() and unregister_capi_driver() functions, and contains
+the following non-private fields, all to be set by the driver before calling
+register_capi_driver():
+
+char name[32]
+	the name of the driver, as a zero-terminated ASCII string
+char revision[32]
+	the revision number of the driver, as a zero-terminated ASCII string
+int (*add_card)(struct capi_driver *driver, capicardparams *data)
+	a callback function pointer (may be NULL)
+
+
+4.2 struct capi_ctr
+
+This structure describes an ISDN device (controller) handled by a Kernel CAPI
+driver. After registration via the attach_capi_ctr() function it is passed to
+all controller specific lower layer interface and callback functions to
+identify the controller to operate on.
+
+It contains the following non-private fields:
+
+- to be set by the driver before calling attach_capi_ctr():
+
+struct module *owner
+	pointer to the driver module owning the device
+
+void *driverdata
+	an opaque pointer to driver specific data, not touched by Kernel CAPI
+
+char name[32]
+	the name of the controller, as a zero-terminated ASCII string
+
+char *driver_name
+	the name of the driver, as a zero-terminated ASCII string
+
+int (*load_firmware)(struct capi_ctr *ctrlr, capiloaddata *ldata)
+	(optional) pointer to a callback function for sending firmware and
+	configuration data to the device
+
+void (*reset_ctr)(struct capi_ctr *ctrlr)
+	pointer to a callback function for performing a reset on the device,
+	releasing all registered applications
+
+void (*register_appl)(struct capi_ctr *ctrlr, u16 applid,
+			capi_register_params *rparam)
+void (*release_appl)(struct capi_ctr *ctrlr, u16 applid)
+	pointers to callback functions for registration and deregistration of
+	applications with the device
+
+u16  (*send_message)(struct capi_ctr *ctrlr, struct sk_buff *skb)
+	pointer to a callback function for sending a CAPI message to the
+	device
+
+char *(*procinfo)(struct capi_ctr *ctrlr)
+	pointer to a callback function returning the entry for the device in
+	the CAPI controller info table, /proc/capi/controller
+
+read_proc_t *ctr_read_proc
+	pointer to the read_proc callback function for the device's proc file
+	system entry, /proc/capi/controllers/<n>; will be called with a
+	pointer to the device's capi_ctr structure as the last (data) argument
+
+- to be filled in before calling capi_ctr_ready():
+
+u8 manu[CAPI_MANUFACTURER_LEN]
+	value to return for CAPI_GET_MANUFACTURER
+
+capi_version version
+	value to return for CAPI_GET_VERSION
+
+capi_profile profile
+	value to return for CAPI_GET_PROFILE
+
+u8 serial[CAPI_SERIAL_LEN]
+	value to return for CAPI_GET_SERIAL
+
+
+5. Lower Layer Interface Functions
+
+(declared in <linux/isdn/capilli.h>)
+
+void register_capi_driver(struct capi_driver *drvr)
+void unregister_capi_driver(struct capi_driver *drvr)
+	register/unregister a driver with Kernel CAPI
+
+int attach_capi_ctr(struct capi_ctr *ctrlr)
+int detach_capi_ctr(struct capi_ctr *ctrlr)
+	register/unregister a device (controller) with Kernel CAPI
+
+void capi_ctr_ready(struct capi_ctr *ctrlr)
+void capi_ctr_reseted(struct capi_ctr *ctrlr)
+	signal controller ready/not ready
+
+void capi_ctr_suspend_output(struct capi_ctr *ctrlr)
+void capi_ctr_resume_output(struct capi_ctr *ctrlr)
+	signal suspend/resume
+
+void capi_ctr_handle_message(struct capi_ctr * ctrlr, u16 applid,
+				struct sk_buff *skb)
+	pass a received CAPI message to Kernel CAPI
+	for forwarding to the specified application
+
+
+6. Helper Functions and Macros
+
+Library functions (from <linux/isdn/capilli.h>):
+
+void capilib_new_ncci(struct list_head *head, u16 applid,
+			u32 ncci, u32 winsize)
+void capilib_free_ncci(struct list_head *head, u16 applid, u32 ncci)
+void capilib_release_appl(struct list_head *head, u16 applid)
+void capilib_release(struct list_head *head)
+void capilib_data_b3_conf(struct list_head *head, u16 applid,
+			u32 ncci, u16 msgid)
+u16  capilib_data_b3_req(struct list_head *head, u16 applid,
+			u32 ncci, u16 msgid)
+
+
+Macros to extract/set element values from/in a CAPI message header
+(from <linux/isdn/capiutil.h>):
+
+Get Macro		Set Macro			Element (Type)
+
+CAPIMSG_LEN(m)		CAPIMSG_SETLEN(m, len)		Total Length (u16)
+CAPIMSG_APPID(m)	CAPIMSG_SETAPPID(m, applid)	ApplID (u16)
+CAPIMSG_COMMAND(m)	CAPIMSG_SETCOMMAND(m,cmd)	Command (u8)
+CAPIMSG_SUBCOMMAND(m)	CAPIMSG_SETSUBCOMMAND(m, cmd)	Subcommand (u8)
+CAPIMSG_CMD(m)		-				Command*256
+							+ Subcommand (u16)
+CAPIMSG_MSGID(m)	CAPIMSG_SETMSGID(m, msgid)	Message Number (u16)
+
+CAPIMSG_CONTROL(m)	CAPIMSG_SETCONTROL(m, contr)	Controller/PLCI/NCCI
+							(u32)
+CAPIMSG_DATALEN(m)	CAPIMSG_SETDATALEN(m, len)	Data Length (u16)
+

Documentation/isdn/README.gigaset

@@ -61,24 +61,28 @@ GigaSet 307x Device Driver
      ---------------------
 2.1. Modules
      -------
-     To get the device working, you have to load the proper kernel module. You
-     can do this using
-         modprobe modulename
-     where modulename is ser_gigaset (M101), usb_gigaset (M105), or
-     bas_gigaset (direct USB connection to the base).
+     For the devices to work, the proper kernel modules have to be loaded.
+     This normally happens automatically when the system detects the USB
+     device (base, M105) or when the line discipline is attached (M101). It
+     can also be triggered manually using the modprobe(8) command, for example
+     for troubleshooting or to pass module parameters.
 
      The module ser_gigaset provides a serial line discipline N_GIGASET_M101
-     which drives the device through the regular serial line driver. To use it,
-     run the Gigaset M101 daemon "gigasetm101d" (also available from
-     http://sourceforge.net/projects/gigaset307x/) with the device file of the
-     RS232 port to the M101 as an argument, for example:
-	 gigasetm101d /dev/ttyS1
-     This will open the device file, set its line discipline to N_GIGASET_M101,
-     and then sleep in the background, keeping the device open so that the
-     line discipline remains active. To deactivate it, kill the daemon, for
-     example with
-	 killall gigasetm101d
-     before disconnecting the device.
+     which drives the device through the regular serial line driver. It must
+     be attached to the serial line to which the M101 is connected with the
+     ldattach(8) command (requires util-linux-ng release 2.14 or later), for
+     example:
+	 ldattach GIGASET_M101 /dev/ttyS1
+     This will open the device file, attach the line discipline to it, and
+     then sleep in the background, keeping the device open so that the line
+     discipline remains active. To deactivate it, kill the daemon, for example
+     with
+	 killall ldattach
+     before disconnecting the device. To have this happen automatically at
+     system startup/shutdown on an LSB compatible system, create and activate
+     an appropriate LSB startup script /etc/init.d/gigaset. (The init name
+     'gigaset' is officially assigned to this project by LANANA.)
+     Alternatively, just add the 'ldattach' command line to /etc/rc.local.
 
 2.2. Device nodes for user space programs
      ------------------------------------
@@ -194,10 +198,11 @@ GigaSet 307x Device Driver
      operation (for wireless access to the base), but are needed for access
      to the M105's own configuration mode (registration to the base, baudrate
      and line format settings, device status queries) via the gigacontr
-     utility. Their use is disabled in the driver by default for safety
-     reasons but can be enabled by setting the kernel configuration option
-     "Support for undocumented USB requests" (GIGASET_UNDOCREQ) to "Y" and
-     recompiling.
+     utility. Their use is controlled by the kernel configuration option
+     "Support for undocumented USB requests" (CONFIG_GIGASET_UNDOCREQ). If you
+     encounter error code -ENOTTY when trying to use some features of the
+     M105, try setting that option to "y" via 'make {x,menu}config' and
+     recompiling the driver.
 
 
 3.   Troubleshooting
@@ -228,6 +233,13 @@ GigaSet 307x Device Driver
      Solution:
         Select Unimodem mode for all DECT data adapters. (see section 2.4.)
 
+     Problem:
+        You want to configure your USB DECT data adapter (M105) but gigacontr
+        reports an error: "/dev/ttyGU0: Inappropriate ioctl for device".
+     Solution:
+        Recompile the usb_gigaset driver with the kernel configuration option
+        CONFIG_GIGASET_UNDOCREQ set to 'y'. (see section 2.6.)
+
 3.2. Telling the driver to provide more information
      ----------------------------------------------
      Building the driver with the "Gigaset debugging" kernel configuration

Documentation/kbuild/makefiles.txt

@@ -40,10 +40,16 @@ This document describes the Linux kernel Makefiles.
 	   --- 6.7 Custom kbuild commands
 	   --- 6.8 Preprocessing linker scripts
 
-	=== 7 Kbuild Variables
-	=== 8 Makefile language
-	=== 9 Credits
-	=== 10 TODO
+	=== 7 Kbuild syntax for exported headers
+		--- 7.1 header-y
+		--- 7.2 objhdr-y
+		--- 7.3 destination-y
+		--- 7.4 unifdef-y (deprecated)
+
+	=== 8 Kbuild Variables
+	=== 9 Makefile language
+	=== 10 Credits
+	=== 11 TODO
 
 === 1 Overview
 
@@ -310,6 +316,16 @@ more details, with real examples.
 		#arch/m68k/fpsp040/Makefile
 		ldflags-y := -x
 
+    subdir-ccflags-y, subdir-asflags-y
+	The two flags listed above are similar to ccflags-y and as-falgs-y.
+	The difference is that the subdir- variants has effect for the kbuild
+	file where tey are present and all subdirectories.
+	Options specified using subdir-* are added to the commandline before
+	the options specified using the non-subdir variants.
+
+	Example:
+		subdir-ccflags-y := -Werror
+
     CFLAGS_$@, AFLAGS_$@
 
 	CFLAGS_$@ and AFLAGS_$@ only apply to commands in current
@@ -1143,8 +1159,69 @@ When kbuild executes, the following steps are followed (roughly):
 	The kbuild infrastructure for *lds file are used in several
 	architecture-specific files.
 
+=== 7 Kbuild syntax for exported headers
+
+The kernel include a set of headers that is exported to userspace.
+Many headers can be exported as-is but other headers requires  a
+minimal pre-processing before they are ready for user-space.
+The pre-processing does:
+- drop kernel specific annotations
+- drop include of compiler.h
+- drop all sections that is kernel internat (guarded by ifdef __KERNEL__)
+
+Each relevant directory contain a file name "Kbuild" which specify the
+headers to be exported.
+See subsequent chapter for the syntax of the Kbuild file.
+
+	--- 7.1 header-y
+
+	header-y specify header files to be exported.
+
+		Example:
+			#include/linux/Kbuild
+			header-y += usb/
+			header-y += aio_abi.h
+
+	The convention is to list one file per line and
+	preferably in alphabetic order.
+
+	header-y also specify which subdirectories to visit.
+	A subdirectory is identified by a trailing '/' which
+	can be seen in the example above for the usb subdirectory.
+
+	Subdirectories are visited before their parent directories.
+
+	--- 7.2 objhdr-y
+
+	objhdr-y specifies generated files to be exported.
+	Generated files are special as they need to be looked
+	up in another directory when doing 'make O=...' builds.
+
+		Example:
+			#include/linux/Kbuild
+			objhdr-y += version.h
+
+	--- 7.3 destination-y
+
+	When an architecture have a set of exported headers that needs to be
+	exported to a different directory destination-y is used.
+	destination-y specify the destination directory for all exported
+	headers in the file where it is present.
+
+		Example:
+			#arch/xtensa/platforms/s6105/include/platform/Kbuild
+			destination-y := include/linux
+
+	In the example above all exported headers in the Kbuild file
+	will be located in the directory "include/linux" when exported.
+
+
+	--- 7.4 unifdef-y (deprecated)
+
+	unifdef-y is deprecated. A direct replacement is header-y.
+
 
-=== 7 Kbuild Variables
+=== 8 Kbuild Variables
 
 The top Makefile exports the following variables:
 
@@ -1206,7 +1283,7 @@ The top Makefile exports the following variables:
 	INSTALL_MOD_STRIP will used as the option(s) to the strip command.
 
 
-=== 8 Makefile language
+=== 9 Makefile language
 
 The kernel Makefiles are designed to be run with GNU Make.  The Makefiles
 use only the documented features of GNU Make, but they do use many
@@ -1225,14 +1302,14 @@ time the left-hand side is used.
 There are some cases where "=" is appropriate.  Usually, though, ":="
 is the right choice.
 
-=== 9 Credits
+=== 10 Credits
 
 Original version made by Michael Elizabeth Chastain, <mailto:mec@shout.net>
 Updates by Kai Germaschewski <kai@tp1.ruhr-uni-bochum.de>
 Updates by Sam Ravnborg <sam@ravnborg.org>
 Language QA by Jan Engelhardt <jengelh@gmx.de>
 
-=== 10 TODO
+=== 11 TODO
 
 - Describe how kbuild supports shipped files with _shipped.
 - Generating offset header files.

Documentation/kernel-doc-nano-HOWTO.txt

@@ -269,7 +269,10 @@ Use the argument mechanism to document members or constants.
 
 Inside a struct description, you can use the "private:" and "public:"
 comment tags.  Structure fields that are inside a "private:" area
-are not listed in the generated output documentation.
+are not listed in the generated output documentation.  The "private:"
+and "public:" tags must begin immediately following a "/*" comment
+marker.  They may optionally include comments between the ":" and the
+ending "*/" marker.
 
 Example:
 
@@ -283,7 +286,7 @@ Example:
 struct my_struct {
     int a;
     int b;
-/* private: */
+/* private: internal use only */
     int c;
 };
 

Documentation/kprobes.txt

@@ -212,7 +212,9 @@ hit, Kprobes calls kp->pre_handler.  After the probed instruction
 is single-stepped, Kprobe calls kp->post_handler.  If a fault
 occurs during execution of kp->pre_handler or kp->post_handler,
 or during single-stepping of the probed instruction, Kprobes calls
-kp->fault_handler.  Any or all handlers can be NULL.
+kp->fault_handler.  Any or all handlers can be NULL. If kp->flags
+is set KPROBE_FLAG_DISABLED, that kp will be registered but disabled,
+so, it's handlers aren't hit until calling enable_kprobe(kp).
 
 NOTE:
 1. With the introduction of the "symbol_name" field to struct kprobe,
@@ -363,6 +365,26 @@ probes) in the specified array, they clear the addr field of those
 incorrect probes. However, other probes in the array are
 unregistered correctly.
 
+4.7 disable_*probe
+
+#include <linux/kprobes.h>
+int disable_kprobe(struct kprobe *kp);
+int disable_kretprobe(struct kretprobe *rp);
+int disable_jprobe(struct jprobe *jp);
+
+Temporarily disables the specified *probe. You can enable it again by using
+enable_*probe(). You must specify the probe which has been registered.
+
+4.8 enable_*probe
+
+#include <linux/kprobes.h>
+int enable_kprobe(struct kprobe *kp);
+int enable_kretprobe(struct kretprobe *rp);
+int enable_jprobe(struct jprobe *jp);
+
+Enables *probe which has been disabled by disable_*probe(). You must specify
+the probe which has been registered.
+
 5. Kprobes Features and Limitations
 
 Kprobes allows multiple probes at the same address.  Currently,
@@ -500,10 +522,14 @@ the probe. If the probed function belongs to a module, the module name
 is also specified. Following columns show probe status. If the probe is on
 a virtual address that is no longer valid (module init sections, module
 virtual addresses that correspond to modules that've been unloaded),
-such probes are marked with [GONE].
+such probes are marked with [GONE]. If the probe is temporarily disabled,
+such probes are marked with [DISABLED].
 
-/debug/kprobes/enabled: Turn kprobes ON/OFF
+/debug/kprobes/enabled: Turn kprobes ON/OFF forcibly.
 
-Provides a knob to globally turn registered kprobes ON or OFF. By default,
-all kprobes are enabled. By echoing "0" to this file, all registered probes
-will be disarmed, till such time a "1" is echoed to this file.
+Provides a knob to globally and forcibly turn registered kprobes ON or OFF.
+By default, all kprobes are enabled. By echoing "0" to this file, all
+registered probes will be disarmed, till such time a "1" is echoed to this
+file. Note that this knob just disarms and arms all kprobes and doesn't
+change each probe's disabling state. This means that disabled kprobes (marked
+[DISABLED]) will be not enabled if you turn ON all kprobes by this knob.

Documentation/laptops/acer-wmi.txt

@@ -1,9 +1,9 @@
 Acer Laptop WMI Extras Driver
 http://code.google.com/p/aceracpi
-Version 0.2
-18th August 2008
+Version 0.3
+4th April 2009
 
-Copyright 2007-2008 Carlos Corbacho <carlos@strangeworlds.co.uk>
+Copyright 2007-2009 Carlos Corbacho <carlos@strangeworlds.co.uk>
 
 acer-wmi is a driver to allow you to control various parts of your Acer laptop
 hardware under Linux which are exposed via ACPI-WMI.
@@ -36,6 +36,10 @@ not possible in kernel space from a 64 bit OS.
 Supported Hardware
 ******************
 
+NOTE: The Acer Aspire One is not supported hardware. It cannot work with
+acer-wmi until Acer fix their ACPI-WMI implementation on them, so has been
+blacklisted until that happens.
+
 Please see the website for the current list of known working hardare:
 
 http://code.google.com/p/aceracpi/wiki/SupportedHardware

Documentation/laptops/thinkpad-acpi.txt

@@ -1,7 +1,7 @@
 		     ThinkPad ACPI Extras Driver
 
-                            Version 0.22
-                        November 23rd,  2008
+                            Version 0.23
+                          April 10th, 2009
 
                Borislav Deianov <borislav@users.sf.net>
              Henrique de Moraes Holschuh <hmh@hmh.eng.br>
@@ -20,7 +20,8 @@ moved to the drivers/misc tree and renamed to thinkpad-acpi for kernel
 kernel 2.6.29 and release 0.22.
 
 The driver is named "thinkpad-acpi".  In some places, like module
-names, "thinkpad_acpi" is used because of userspace issues.
+names and log messages, "thinkpad_acpi" is used because of userspace
+issues.
 
 "tpacpi" is used as a shorthand where "thinkpad-acpi" would be too
 long due to length limitations on some Linux kernel versions.
@@ -37,7 +38,7 @@ detailed description):
 	- ThinkLight on and off
 	- limited docking and undocking
 	- UltraBay eject
-	- CMOS control
+	- CMOS/UCMS control
 	- LED control
 	- ACPI sounds
 	- temperature sensors
@@ -46,6 +47,7 @@ detailed description):
 	- Volume control
 	- Fan control and monitoring: fan speed, fan enable/disable
 	- WAN enable and disable
+	- UWB enable and disable
 
 A compatibility table by model and feature is maintained on the web
 site, http://ibm-acpi.sf.net/. I appreciate any success or failure
@@ -53,7 +55,7 @@ reports, especially if they add to or correct the compatibility table.
 Please include the following information in your report:
 
 	- ThinkPad model name
-	- a copy of your DSDT, from /proc/acpi/dsdt
+	- a copy of your ACPI tables, using the "acpidump" utility
 	- a copy of the output of dmidecode, with serial numbers
 	  and UUIDs masked off
 	- which driver features work and which don't
@@ -66,17 +68,18 @@ Installation
 ------------
 
 If you are compiling this driver as included in the Linux kernel
-sources, simply enable the CONFIG_THINKPAD_ACPI option, and optionally
-enable the CONFIG_THINKPAD_ACPI_BAY option if you want the
-thinkpad-specific bay functionality.
+sources, look for the CONFIG_THINKPAD_ACPI Kconfig option.
+It is located on the menu path: "Device Drivers" -> "X86 Platform
+Specific Device Drivers" -> "ThinkPad ACPI Laptop Extras".
+
 
 Features
 --------
 
 The driver exports two different interfaces to userspace, which can be
 used to access the features it provides.  One is a legacy procfs-based
-interface, which will be removed at some time in the distant future.
-The other is a new sysfs-based interface which is not complete yet.
+interface, which will be removed at some time in the future.  The other
+is a new sysfs-based interface which is not complete yet.
 
 The procfs interface creates the /proc/acpi/ibm directory.  There is a
 file under that directory for each feature it supports.  The procfs
@@ -111,15 +114,17 @@ The version of thinkpad-acpi's sysfs interface is exported by the driver
 as a driver attribute (see below).
 
 Sysfs driver attributes are on the driver's sysfs attribute space,
-for 2.6.23 this is /sys/bus/platform/drivers/thinkpad_acpi/ and
+for 2.6.23+ this is /sys/bus/platform/drivers/thinkpad_acpi/ and
 /sys/bus/platform/drivers/thinkpad_hwmon/
 
 Sysfs device attributes are on the thinkpad_acpi device sysfs attribute
-space, for 2.6.23 this is /sys/devices/platform/thinkpad_acpi/.
+space, for 2.6.23+ this is /sys/devices/platform/thinkpad_acpi/.
 
 Sysfs device attributes for the sensors and fan are on the
 thinkpad_hwmon device's sysfs attribute space, but you should locate it
-looking for a hwmon device with the name attribute of "thinkpad".
+looking for a hwmon device with the name attribute of "thinkpad", or
+better yet, through libsensors.
+
 
 Driver version
 --------------
@@ -129,6 +134,7 @@ sysfs driver attribute: version
 
 The driver name and version. No commands can be written to this file.
 
+
 Sysfs interface version
 -----------------------
 
@@ -160,6 +166,7 @@ expect that an attribute might not be there, and deal with it properly
 (an attribute not being there *is* a valid way to make it clear that a
 feature is not available in sysfs).
 
+
 Hot keys
 --------
 
@@ -172,17 +179,14 @@ system.  Enabling the hotkey functionality of thinkpad-acpi signals the
 firmware that such a driver is present, and modifies how the ThinkPad
 firmware will behave in many situations.
 
-The driver enables the hot key feature automatically when loaded.  The
-feature can later be disabled and enabled back at runtime.  The driver
-will also restore the hot key feature to its previous state and mask
-when it is unloaded.
+The driver enables the HKEY ("hot key") event reporting automatically
+when loaded, and disables it when it is removed.
 
-When the hotkey feature is enabled and the hot key mask is set (see
-below), the driver will report HKEY events in the following format:
+The driver will report HKEY events in the following format:
 
 	ibm/hotkey HKEY 00000080 0000xxxx
 
-Some of these events refer to hot key presses, but not all.
+Some of these events refer to hot key presses, but not all of them.
 
 The driver will generate events over the input layer for hot keys and
 radio switches, and over the ACPI netlink layer for other events.  The
@@ -214,13 +218,17 @@ procfs notes:
 
 The following commands can be written to the /proc/acpi/ibm/hotkey file:
 
-	echo enable > /proc/acpi/ibm/hotkey -- enable the hot keys feature
-	echo disable > /proc/acpi/ibm/hotkey -- disable the hot keys feature
 	echo 0xffffffff > /proc/acpi/ibm/hotkey -- enable all hot keys
 	echo 0 > /proc/acpi/ibm/hotkey -- disable all possible hot keys
 	... any other 8-hex-digit mask ...
 	echo reset > /proc/acpi/ibm/hotkey -- restore the original mask
 
+The following commands have been deprecated and will cause the kernel
+to log a warning:
+
+	echo enable > /proc/acpi/ibm/hotkey -- does nothing
+	echo disable > /proc/acpi/ibm/hotkey -- returns an error
+
 The procfs interface does not support NVRAM polling control.  So as to
 maintain maximum bug-to-bug compatibility, it does not report any masks,
 nor does it allow one to manipulate the hot key mask when the firmware
@@ -229,12 +237,9 @@ does not support masks at all, even if NVRAM polling is in use.
 sysfs notes:
 
 	hotkey_bios_enabled:
-		Returns the status of the hot keys feature when
-		thinkpad-acpi was loaded.  Upon module unload, the hot
-		key feature status will be restored to this value.
+		DEPRECATED, WILL BE REMOVED SOON.
 
-		0: hot keys were disabled
-		1: hot keys were enabled (unusual)
+		Returns 0.
 
 	hotkey_bios_mask:
 		Returns the hot keys mask when thinkpad-acpi was loaded.
@@ -242,13 +247,10 @@ sysfs notes:
 		to this value.
 
 	hotkey_enable:
-		Enables/disables the hot keys feature in the ACPI
-		firmware, and reports current status of the hot keys
-		feature.  Has no effect on the NVRAM hot key polling
-		functionality.
+		DEPRECATED, WILL BE REMOVED SOON.
 
-		0: disables the hot keys feature / feature disabled
-		1: enables the hot keys feature / feature enabled
+		0: returns -EPERM
+		1: does nothing
 
 	hotkey_mask:
 		bit mask to enable driver-handling (and depending on
@@ -618,6 +620,7 @@ For Lenovo models *with* ACPI backlight control:
    and map them to KEY_BRIGHTNESS_UP and KEY_BRIGHTNESS_DOWN.  Process
    these keys on userspace somehow (e.g. by calling xbacklight).
 
+
 Bluetooth
 ---------
 
@@ -628,6 +631,9 @@ sysfs rfkill class: switch "tpacpi_bluetooth_sw"
 This feature shows the presence and current state of a ThinkPad
 Bluetooth device in the internal ThinkPad CDC slot.
 
+If the ThinkPad supports it, the Bluetooth state is stored in NVRAM,
+so it is kept across reboots and power-off.
+
 Procfs notes:
 
 If Bluetooth is installed, the following commands can be used:
@@ -652,6 +658,7 @@ Sysfs notes:
 	rfkill controller switch "tpacpi_bluetooth_sw": refer to
 	Documentation/rfkill.txt for details.
 
+
 Video output control -- /proc/acpi/ibm/video
 --------------------------------------------
 
@@ -693,11 +700,8 @@ Fn-F7 from working. This also disables the video output switching
 features of this driver, as it uses the same ACPI methods as
 Fn-F7. Video switching on the console should still work.
 
-UPDATE: There's now a patch for the X.org Radeon driver which
-addresses this issue. Some people are reporting success with the patch
-while others are still having problems. For more information:
+UPDATE: refer to https://bugs.freedesktop.org/show_bug.cgi?id=2000
 
-https://bugs.freedesktop.org/show_bug.cgi?id=2000
 
 ThinkLight control
 ------------------
@@ -720,10 +724,11 @@ The ThinkLight sysfs interface is documented by the LED class
 documentation, in Documentation/leds-class.txt.  The ThinkLight LED name
 is "tpacpi::thinklight".
 
-Due to limitations in the sysfs LED class, if the status of the thinklight
+Due to limitations in the sysfs LED class, if the status of the ThinkLight
 cannot be read or if it is unknown, thinkpad-acpi will report it as "off".
 It is impossible to know if the status returned through sysfs is valid.
 
+
 Docking / undocking -- /proc/acpi/ibm/dock
 ------------------------------------------
 
@@ -784,6 +789,7 @@ the only docking stations currently supported are the X-series
 UltraBase docks and "dumb" port replicators like the Mini Dock (the
 latter don't need any ACPI support, actually).
 
+
 UltraBay eject -- /proc/acpi/ibm/bay
 ------------------------------------
 
@@ -847,8 +853,9 @@ supported. Use "eject2" instead of "eject" for the second bay.
 Note: the UltraBay eject support on the 600e/x, A22p and A3x is
 EXPERIMENTAL and may not work as expected. USE WITH CAUTION!
 
-CMOS control
-------------
+
+CMOS/UCMS control
+-----------------
 
 procfs: /proc/acpi/ibm/cmos
 sysfs device attribute: cmos_command
@@ -882,6 +889,7 @@ The cmos command interface is prone to firmware split-brain problems, as
 in newer ThinkPads it is just a compatibility layer.  Do not use it, it is
 exported just as a debug tool.
 
+
 LED control
 -----------
 
@@ -893,6 +901,17 @@ some older ThinkPad models, it is possible to query the status of the
 LED indicators as well.  Newer ThinkPads cannot query the real status
 of the LED indicators.
 
+Because misuse of the LEDs could induce an unaware user to perform
+dangerous actions (like undocking or ejecting a bay device while the
+buses are still active), or mask an important alarm (such as a nearly
+empty battery, or a broken battery), access to most LEDs is
+restricted.
+
+Unrestricted access to all LEDs requires that thinkpad-acpi be
+compiled with the CONFIG_THINKPAD_ACPI_UNSAFE_LEDS option enabled.
+Distributions must never enable this option.  Individual users that
+are aware of the consequences are welcome to enabling it.
+
 procfs notes:
 
 The available commands are:
@@ -939,6 +958,7 @@ ThinkPad indicator LED should blink in hardware accelerated mode, use the
 "timer" trigger, and leave the delay_on and delay_off parameters set to
 zero (to request hardware acceleration autodetection).
 
+
 ACPI sounds -- /proc/acpi/ibm/beep
 ----------------------------------
 
@@ -968,6 +988,7 @@ X40:
 	16 - one medium-pitched beep repeating constantly, stop with 17
 	17 - stop 16
 
+
 Temperature sensors
 -------------------
 
@@ -1115,6 +1136,7 @@ registers contain the current battery capacity, etc. If you experiment
 with this, do send me your results (including some complete dumps with
 a description of the conditions when they were taken.)
 
+
 LCD brightness control
 ----------------------
 
@@ -1124,10 +1146,9 @@ sysfs backlight device "thinkpad_screen"
 This feature allows software control of the LCD brightness on ThinkPad
 models which don't have a hardware brightness slider.
 
-It has some limitations: the LCD backlight cannot be actually turned on or
-off by this interface, and in many ThinkPad models, the "dim while on
-battery" functionality will be enabled by the BIOS when this interface is
-used, and cannot be controlled.
+It has some limitations: the LCD backlight cannot be actually turned
+on or off by this interface, it just controls the backlight brightness
+level.
 
 On IBM (and some of the earlier Lenovo) ThinkPads, the backlight control
 has eight brightness levels, ranging from 0 to 7.  Some of the levels
@@ -1136,10 +1157,15 @@ display backlight brightness control methods have 16 levels, ranging
 from 0 to 15.
 
 There are two interfaces to the firmware for direct brightness control,
-EC and CMOS.  To select which one should be used, use the
+EC and UCMS (or CMOS).  To select which one should be used, use the
 brightness_mode module parameter: brightness_mode=1 selects EC mode,
-brightness_mode=2 selects CMOS mode, brightness_mode=3 selects both EC
-and CMOS.  The driver tries to auto-detect which interface to use.
+brightness_mode=2 selects UCMS mode, brightness_mode=3 selects EC
+mode with NVRAM backing (so that brightness changes are remembered
+across shutdown/reboot).
+
+The driver tries to select which interface to use from a table of
+defaults for each ThinkPad model.  If it makes a wrong choice, please
+report this as a bug, so that we can fix it.
 
 When display backlight brightness controls are available through the
 standard ACPI interface, it is best to use it instead of this direct
@@ -1201,6 +1227,7 @@ WARNING:
     and maybe reduce the life of the backlight lamps by needlessly kicking
     its level up and down at every change.
 
+
 Volume control -- /proc/acpi/ibm/volume
 ---------------------------------------
 
@@ -1217,6 +1244,11 @@ distinct. The unmute the volume after the mute command, use either the
 up or down command (the level command will not unmute the volume).
 The current volume level and mute state is shown in the file.
 
+The ALSA mixer interface to this feature is still missing, but patches
+to add it exist.  That problem should be addressed in the not so
+distant future.
+
+
 Fan control and monitoring: fan speed, fan enable/disable
 ---------------------------------------------------------
 
@@ -1383,8 +1415,11 @@ procfs: /proc/acpi/ibm/wan
 sysfs device attribute: wwan_enable (deprecated)
 sysfs rfkill class: switch "tpacpi_wwan_sw"
 
-This feature shows the presence and current state of a W-WAN (Sierra
-Wireless EV-DO) device.
+This feature shows the presence and current state of the built-in
+Wireless WAN device.
+
+If the ThinkPad supports it, the WWAN state is stored in NVRAM,
+so it is kept across reboots and power-off.
 
 It was tested on a Lenovo ThinkPad X60. It should probably work on other
 ThinkPad models which come with this module installed.
@@ -1413,6 +1448,7 @@ Sysfs notes:
 	rfkill controller switch "tpacpi_wwan_sw": refer to
 	Documentation/rfkill.txt for details.
 
+
 EXPERIMENTAL: UWB
 -----------------
 
@@ -1431,6 +1467,7 @@ Sysfs notes:
 	rfkill controller switch "tpacpi_uwb_sw": refer to
 	Documentation/rfkill.txt for details.
 
+
 Multiple Commands, Module Parameters
 ------------------------------------
 
@@ -1445,6 +1482,7 @@ for example:
 
 	modprobe thinkpad_acpi hotkey=enable,0xffff video=auto_disable
 
+
 Enabling debugging output
 -------------------------
 
@@ -1457,8 +1495,15 @@ will enable all debugging output classes.  It takes a bitmask, so
 to enable more than one output class, just add their values.
 
 	Debug bitmask		Description
+	0x8000			Disclose PID of userspace programs
+				accessing some functions of the driver
 	0x0001			Initialization and probing
 	0x0002			Removal
+	0x0004			RF Transmitter control (RFKILL)
+				(bluetooth, WWAN, UWB...)
+	0x0008			HKEY event interface, hotkeys
+	0x0010			Fan control
+	0x0020			Backlight brightness
 
 There is also a kernel build option to enable more debugging
 information, which may be necessary to debug driver problems.
@@ -1467,6 +1512,7 @@ The level of debugging information output by the driver can be changed
 at runtime through sysfs, using the driver attribute debug_level.  The
 attribute takes the same bitmask as the debug module parameter above.
 
+
 Force loading of module
 -----------------------
 
@@ -1505,3 +1551,7 @@ Sysfs interface changelog:
 
 0x020200:	Add poll()/select() support to the following attributes:
 		hotkey_radio_sw, wakeup_hotunplug_complete, wakeup_reason
+
+0x020300:	hotkey enable/disable support removed, attributes
+		hotkey_bios_enabled and hotkey_enable deprecated and
+		marked for removal.

Documentation/lguest/.gitignore

@@ -0,0 +1 @@
+lguest

Documentation/lguest/lguest.c

@@ -1630,6 +1630,13 @@ static bool service_io(struct device *dev)
 		}
 	}
 
+	/* OK, so we noted that it was pretty poor to use an fdatasync as a
+	 * barrier.  But Christoph Hellwig points out that we need a sync
+	 * *afterwards* as well: "Barriers specify no reordering to the front
+	 * or the back."  And Jens Axboe confirmed it, so here we are: */
+	if (out->type & VIRTIO_BLK_T_BARRIER)
+		fdatasync(vblk->fd);
+
 	/* We can't trigger an IRQ, because we're not the Launcher.  It does
 	 * that when we tell it we're done. */
 	add_used(dev->vq, head, wlen);

Documentation/lguest/lguest.txt

@@ -3,11 +3,11 @@
  /,    /`      - or, A Young Coder's Illustrated Hypervisor
  \\"--\\    http://lguest.ozlabs.org
 
-Lguest is designed to be a minimal hypervisor for the Linux kernel, for
-Linux developers and users to experiment with virtualization with the
-minimum of complexity.  Nonetheless, it should have sufficient
-features to make it useful for specific tasks, and, of course, you are
-encouraged to fork and enhance it (see drivers/lguest/README).
+Lguest is designed to be a minimal 32-bit x86 hypervisor for the Linux kernel,
+for Linux developers and users to experiment with virtualization with the
+minimum of complexity.  Nonetheless, it should have sufficient features to
+make it useful for specific tasks, and, of course, you are encouraged to fork
+and enhance it (see drivers/lguest/README).
 
 Features:
 
@@ -37,6 +37,7 @@ Running Lguest:
      "Paravirtualized guest support" = Y
         "Lguest guest support" = Y
      "High Memory Support" = off/4GB
+     "PAE (Physical Address Extension) Support" = N
      "Alignment value to which kernel should be aligned" = 0x100000
         (CONFIG_PARAVIRT=y, CONFIG_LGUEST_GUEST=y, CONFIG_HIGHMEM64G=n and
          CONFIG_PHYSICAL_ALIGN=0x100000)

Documentation/lockdep-design.txt

@@ -27,33 +27,37 @@ lock-class.
 State
 -----
 
-The validator tracks lock-class usage history into 5 separate state bits:
+The validator tracks lock-class usage history into 4n + 1 separate state bits:
 
-- 'ever held in hardirq context'                    [ == hardirq-safe   ]
-- 'ever held in softirq context'                    [ == softirq-safe   ]
-- 'ever held with hardirqs enabled'                 [ == hardirq-unsafe ]
-- 'ever held with softirqs and hardirqs enabled'    [ == softirq-unsafe ]
+- 'ever held in STATE context'
+- 'ever head as readlock in STATE context'
+- 'ever head with STATE enabled'
+- 'ever head as readlock with STATE enabled'
+
+Where STATE can be either one of (kernel/lockdep_states.h)
+ - hardirq
+ - softirq
+ - reclaim_fs
 
 - 'ever used'                                       [ == !unused        ]
 
-When locking rules are violated, these 4 state bits are presented in the
-locking error messages, inside curlies.  A contrived example:
+When locking rules are violated, these state bits are presented in the
+locking error messages, inside curlies. A contrived example:
 
    modprobe/2287 is trying to acquire lock:
-    (&sio_locks[i].lock){--..}, at: [<c02867fd>] mutex_lock+0x21/0x24
+    (&sio_locks[i].lock){-.-...}, at: [<c02867fd>] mutex_lock+0x21/0x24
 
    but task is already holding lock:
-    (&sio_locks[i].lock){--..}, at: [<c02867fd>] mutex_lock+0x21/0x24
+    (&sio_locks[i].lock){-.-...}, at: [<c02867fd>] mutex_lock+0x21/0x24
 
 
-The bit position indicates hardirq, softirq, hardirq-read,
-softirq-read respectively, and the character displayed in each
-indicates:
+The bit position indicates STATE, STATE-read, for each of the states listed
+above, and the character displayed in each indicates:
 
-   '.'  acquired while irqs disabled
-   '+'  acquired in irq context
-   '-'  acquired with irqs enabled
-   '?' read acquired in irq context with irqs enabled.
+   '.'  acquired while irqs disabled and not in irq context
+   '-'  acquired in irq context
+   '+'  acquired with irqs enabled
+   '?'  acquired in irq context with irqs enabled.
 
 Unused mutexes cannot be part of the cause of an error.
 

Documentation/logo.txt

@@ -1,4 +1,13 @@
-Tux is taking a three month sabbatical to work as a barber, so Tuz is
-standing in.  He's taken pains to ensure you'll hardly notice.
+This is the full-colour version of the currently unofficial Linux logo
+("currently unofficial" just means that there has been no paperwork and
+that I have not really announced it yet).  It was created by Larry Ewing,
+and is freely usable as long as you acknowledge Larry as the original
+artist. 
+
+Note that there are black-and-white versions of this available that
+scale down to smaller sizes and are better for letterheads or whatever
+you want to use it for: for the full range of logos take a look at
+Larry's web-page:
+
+	http://www.isc.tamu.edu/~lewing/linux/
 
-Image by Andrew McGown and Josh Bush.  Image is licensed CC BY-SA.

Documentation/md.txt

@@ -164,15 +164,19 @@ All md devices contain:
   raid_disks
      a text file with a simple number indicating the number of devices
      in a fully functional array.  If this is not yet known, the file
-     will be empty.  If an array is being resized (not currently
-     possible) this will contain the larger of the old and new sizes.
-     Some raid level (RAID1) allow this value to be set while the
-     array is active.  This will reconfigure the array.   Otherwise
-     it can only be set while assembling an array.
+     will be empty.  If an array is being resized this will contain
+     the new number of devices.
+     Some raid levels allow this value to be set while the array is
+     active.  This will reconfigure the array.   Otherwise it can only
+     be set while assembling an array.
+     A change to this attribute will not be permitted if it would
+     reduce the size of the array.  To reduce the number of drives
+     in an e.g. raid5, the array size must first be reduced by
+     setting the 'array_size' attribute.
 
   chunk_size
-     This is the size if bytes for 'chunks' and is only relevant to
-     raid levels that involve striping (1,4,5,6,10). The address space
+     This is the size in bytes for 'chunks' and is only relevant to
+     raid levels that involve striping (0,4,5,6,10). The address space
      of the array is conceptually divided into chunks and consecutive
      chunks are striped onto neighbouring devices.
      The size should be at least PAGE_SIZE (4k) and should be a power
@@ -183,6 +187,20 @@ All md devices contain:
      simply a number that is interpretted differently by different
      levels.  It can be written while assembling an array.
 
+  array_size
+     This can be used to artificially constrain the available space in
+     the array to be less than is actually available on the combined
+     devices.  Writing a number (in Kilobytes) which is less than
+     the available size will set the size.  Any reconfiguration of the
+     array (e.g. adding devices) will not cause the size to change.
+     Writing the word 'default' will cause the effective size of the
+     array to be whatever size is actually available based on
+     'level', 'chunk_size' and 'component_size'.
+
+     This can be used to reduce the size of the array before reducing
+     the number of devices in a raid4/5/6, or to support external
+     metadata formats which mandate such clipping.
+
   reshape_position
      This is either "none" or a sector number within the devices of
      the array where "reshape" is up to.  If this is set, the three
@@ -207,6 +225,11 @@ All md devices contain:
      about the array.  It can be 0.90 (traditional format), 1.0, 1.1,
      1.2 (newer format in varying locations) or "none" indicating that
      the kernel isn't managing metadata at all.
+     Alternately it can be "external:" followed by a string which
+     is set by user-space.  This indicates that metadata is managed
+     by a user-space program.  Any device failure or other event that
+     requires a metadata update will cause array activity to be
+     suspended until the event is acknowledged.
 
   resync_start
      The point at which resync should start.  If no resync is needed,