Get rid of Documentation/feature-removal.txt

This file has turned out to be a pure write-only file that causes merge
conflicts and has no actual redeeming features.

There is never any reason to add stuff to this idiotic file.  Either
something isn't getting used, and you should just remove it, or there is
no excuse for removing it in the first place.  Just stop the idiocy.

It has also been the excuse for just plain bad behavior ("Hey, I don't
like xyz, so let's mark it for removal" followed by "Hey, look, it been
in feature-removal.txt for six months now, so we should remove it").

The recent bogus setitimer() ABI change request was just the most recent
example of pointless and incorrect mental masturbation involving this
file, and I'm tired of the silly and pointless conflicts in the file.

This removal was discussed during the recent kernel summit, and while
Steven Rostedt suggested we should just enter the file itself in the
feature-removal schedule (to see if anybody who edits the file actually
looks at it), that's cute but non-productive.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/feature-removal-schedule.txt

@@ -1,586 +0,0 @@
-The following is a list of files and features that are going to be
-removed in the kernel source tree.  Every entry should contain what
-exactly is going away, why it is happening, and who is going to be doing
-the work.  When the feature is removed from the kernel, it should also
-be removed from this file.  The suggested deprecation period is 3 releases.
-
----------------------------
-
-What:	ddebug_query="query" boot cmdline param
-When:	v3.8
-Why:	obsoleted by dyndbg="query" and module.dyndbg="query"
-Who:	Jim Cromie <jim.cromie@gmail.com>, Jason Baron <jbaron@redhat.com>
-
----------------------------
-
-What: /proc/sys/vm/nr_pdflush_threads
-When: 2012
-Why: Since pdflush is deprecated, the interface exported in /proc/sys/vm/
-     should be removed.
-Who: Wanpeng Li <liwp@linux.vnet.ibm.com>
-
----------------------------
-
-What:	CONFIG_APM_CPU_IDLE, and its ability to call APM BIOS in idle
-When:	2012
-Why:	This optional sub-feature of APM is of dubious reliability,
-	and ancient APM laptops are likely better served by calling HLT.
-	Deleting CONFIG_APM_CPU_IDLE allows x86 to stop exporting
-	the pm_idle function pointer to modules.
-Who:	Len Brown <len.brown@intel.com>
-
-----------------------------
-
-What:	x86_32 "no-hlt" cmdline param
-When:	2012
-Why:	remove a branch from idle path, simplify code used by everybody.
-	This option disabled the use of HLT in idle and machine_halt()
-	for hardware that was flakey 15-years ago.  Today we have
-	"idle=poll" that removed HLT from idle, and so if such a machine
-	is still running the upstream kernel, "idle=poll" is likely sufficient.
-Who:	Len Brown <len.brown@intel.com>
-
-----------------------------
-
-What:	x86 "idle=mwait" cmdline param
-When:	2012
-Why:	simplify x86 idle code
-Who:	Len Brown <len.brown@intel.com>
-
-----------------------------
-
-What:	PRISM54
-When:	2.6.34
-
-Why:	prism54 FullMAC PCI / Cardbus devices used to be supported only by the
-	prism54 wireless driver. After Intersil stopped selling these
-	devices in preference for the newer more flexible SoftMAC devices
-	a SoftMAC device driver was required and prism54 did not support
-	them. The p54pci driver now exists and has been present in the kernel for
-	a while. This driver supports both SoftMAC devices and FullMAC devices.
-	The main difference between these devices was the amount of memory which
-	could be used for the firmware. The SoftMAC devices support a smaller
-	amount of memory. Because of this the SoftMAC firmware fits into FullMAC
-	devices's memory. p54pci supports not only PCI / Cardbus but also USB
-	and SPI. Since p54pci supports all devices prism54 supports
-	you will have a conflict. I'm not quite sure how distributions are
-	handling this conflict right now. prism54 was kept around due to
-	claims users may experience issues when using the SoftMAC driver.
-	Time has passed users have not reported issues. If you use prism54
-	and for whatever reason you cannot use p54pci please let us know!
-	E-mail us at: linux-wireless@vger.kernel.org
-
-	For more information see the p54 wiki page:
-
-	http://wireless.kernel.org/en/users/Drivers/p54
-
-Who:	Luis R. Rodriguez <lrodriguez@atheros.com>
-
----------------------------
-
-What:	The ieee80211_regdom module parameter
-When:	March 2010 / desktop catchup
-
-Why:	This was inherited by the CONFIG_WIRELESS_OLD_REGULATORY code,
-	and currently serves as an option for users to define an
-	ISO / IEC 3166 alpha2 code for the country they are currently
-	present in. Although there are userspace API replacements for this
-	through nl80211 distributions haven't yet caught up with implementing
-	decent alternatives through standard GUIs. Although available as an
-	option through iw or wpa_supplicant its just a matter of time before
-	distributions pick up good GUI options for this. The ideal solution
-	would actually consist of intelligent designs which would do this for
-	the user automatically even when travelling through different countries.
-	Until then we leave this module parameter as a compromise.
-
-	When userspace improves with reasonable widely-available alternatives for
-	this we will no longer need this module parameter. This entry hopes that
-	by the super-futuristically looking date of "March 2010" we will have
-	such replacements widely available.
-
-Who:	Luis R. Rodriguez <lrodriguez@atheros.com>
-
----------------------------
-
-What:	dev->power.power_state
-When:	July 2007
-Why:	Broken design for runtime control over driver power states, confusing
-	driver-internal runtime power management with:  mechanisms to support
-	system-wide sleep state transitions; event codes that distinguish
-	different phases of swsusp "sleep" transitions; and userspace policy
-	inputs.  This framework was never widely used, and most attempts to
-	use it were broken.  Drivers should instead be exposing domain-specific
-	interfaces either to kernel or to userspace.
-Who:	Pavel Machek <pavel@ucw.cz>
-
----------------------------
-
-What:	/proc/<pid>/oom_adj
-When:	August 2012
-Why:	/proc/<pid>/oom_adj allows userspace to influence the oom killer's
-	badness heuristic used to determine which task to kill when the kernel
-	is out of memory.
-
-	The badness heuristic has since been rewritten since the introduction of
-	this tunable such that its meaning is deprecated.  The value was
-	implemented as a bitshift on a score generated by the badness()
-	function that did not have any precise units of measure.  With the
-	rewrite, the score is given as a proportion of available memory to the
-	task allocating pages, so using a bitshift which grows the score
-	exponentially is, thus, impossible to tune with fine granularity.
-
-	A much more powerful interface, /proc/<pid>/oom_score_adj, was
-	introduced with the oom killer rewrite that allows users to increase or
-	decrease the badness score linearly.  This interface will replace
-	/proc/<pid>/oom_adj.
-
-	A warning will be emitted to the kernel log if an application uses this
-	deprecated interface.  After it is printed once, future warnings will be
-	suppressed until the kernel is rebooted.
-
----------------------------
-
-What:	remove EXPORT_SYMBOL(kernel_thread)
-When:	August 2006
-Files:	arch/*/kernel/*_ksyms.c
-Check:	kernel_thread
-Why:	kernel_thread is a low-level implementation detail.  Drivers should
-        use the <linux/kthread.h> API instead which shields them from
-	implementation details and provides a higherlevel interface that
-	prevents bugs and code duplication
-Who:	Christoph Hellwig <hch@lst.de>
-
----------------------------
-
-What:	Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
-	(temporary transition config option provided until then)
-	The transition config option will also be removed at the same time.
-When:	before 2.6.19
-Why:	Unused symbols are both increasing the size of the kernel binary
-	and are often a sign of "wrong API"
-Who:	Arjan van de Ven <arjan@linux.intel.com>
-
----------------------------
-
-What:	PHYSDEVPATH, PHYSDEVBUS, PHYSDEVDRIVER in the uevent environment
-When:	October 2008
-Why:	The stacking of class devices makes these values misleading and
-	inconsistent.
-	Class devices should not carry any of these properties, and bus
-	devices have SUBSYTEM and DRIVER as a replacement.
-Who:	Kay Sievers <kay.sievers@suse.de>
-
----------------------------
-
-What:	ACPI procfs interface
-When:	July 2008
-Why:	ACPI sysfs conversion should be finished by January 2008.
-	ACPI procfs interface will be removed in July 2008 so that
-	there is enough time for the user space to catch up.
-Who:	Zhang Rui <rui.zhang@intel.com>
-
----------------------------
-
-What:	CONFIG_ACPI_PROCFS_POWER
-When:	2.6.39
-Why:	sysfs I/F for ACPI power devices, including AC and Battery,
-        has been working in upstream kernel since 2.6.24, Sep 2007.
-	In 2.6.37, we make the sysfs I/F always built in and this option
-	disabled by default.
-	Remove this option and the ACPI power procfs interface in 2.6.39.
-Who:	Zhang Rui <rui.zhang@intel.com>
-
----------------------------
-
-What:	/proc/acpi/event
-When:	February 2008
-Why:	/proc/acpi/event has been replaced by events via the input layer
-	and netlink since 2.6.23.
-Who:	Len Brown <len.brown@intel.com>
-
----------------------------
-
-What:	i386/x86_64 bzImage symlinks
-When:	April 2010
-
-Why:	The i386/x86_64 merge provides a symlink to the old bzImage
-	location so not yet updated user space tools, e.g. package
-	scripts, do not break.
-Who:	Thomas Gleixner <tglx@linutronix.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.
-	So it _could_ be removed _any_ time now, if it conflicts with something new.
-Why:	The support code for the old firmware hurts code readability/maintainability
-	and slightly hurts runtime performance. Bugfixes for the old firmware
-	are not provided by Broadcom anymore.
-Who:	Michael Buesch <m@bues.ch>
-
----------------------------
-
-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:	sysfs ui for changing p4-clockmod parameters
-When:	September 2009
-Why:	See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and
-	e088e4c9cdb618675874becb91b2fd581ee707e6.
-	Removal is subject to fixing any remaining bugs in ACPI which may
-	cause the thermal throttling not to happen at the right time.
-Who:	Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com>
-
------------------------------
-
-What:	CONFIG_RFKILL_INPUT
-When:	2.6.33
-Why:	Should be implemented in userspace, policy daemon.
-Who:	Johannes Berg <johannes@sipsolutions.net>
-
-----------------------------
-
-What:	sound-slot/service-* module aliases and related clutters in
-	sound/sound_core.c
-When:	August 2010
-Why:	OSS sound_core grabs all legacy minors (0-255) of SOUND_MAJOR
-	(14) and requests modules using custom sound-slot/service-*
-	module aliases.  The only benefit of doing this is allowing
-	use of custom module aliases which might as well be considered
-	a bug at this point.  This preemptive claiming prevents
-	alternative OSS implementations.
-
-	Till the feature is removed, the kernel will be requesting
-	both sound-slot/service-* and the standard char-major-* module
-	aliases and allow turning off the pre-claiming selectively via
-	CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss
-	kernel parameter.
-
-	After the transition phase is complete, both the custom module
-	aliases and switches to disable it will go away.  This removal
-	will also allow making ALSA OSS emulation independent of
-	sound_core.  The dependency will be broken then too.
-Who:	Tejun Heo <tj@kernel.org>
-
-----------------------------
-
-What:	sysfs-class-rfkill state file
-When:	Feb 2014
-Files:	net/rfkill/core.c
-Why: 	Documented as obsolete since Feb 2010. This file is limited to 3
-	states while the rfkill drivers can have 4 states.
-Who: 	anybody or Florian Mickler <florian@mickler.org>
-
-----------------------------
-
-What: 	sysfs-class-rfkill claim file
-When:	Feb 2012
-Files:	net/rfkill/core.c
-Why:	It is not possible to claim an rfkill driver since 2007. This is
-	Documented as obsolete since Feb 2010.
-Who: 	anybody or Florian Mickler <florian@mickler.org>
-
-----------------------------
-
-What:	iwlwifi 50XX module parameters
-When:	3.0
-Why:	The "..50" modules parameters were used to configure 5000 series and
-	up devices; different set of module parameters also available for 4965
-	with same functionalities. Consolidate both set into single place
-	in drivers/net/wireless/iwlwifi/iwl-agn.c
-
-Who:	Wey-Yi Guy <wey-yi.w.guy@intel.com>
-
-----------------------------
-
-What:	iwl4965 alias support
-When:	3.0
-Why:	Internal alias support has been present in module-init-tools for some
-	time, the MODULE_ALIAS("iwl4965") boilerplate aliases can be removed
-	with no impact.
-
-Who:	Wey-Yi Guy <wey-yi.w.guy@intel.com>
-
----------------------------
-
-What:	xt_NOTRACK
-Files:	net/netfilter/xt_NOTRACK.c
-When:	April 2011
-Why:	Superseded by xt_CT
-Who:	Netfilter developer team <netfilter-devel@vger.kernel.org>
-
-----------------------------
-
-What:	IRQF_DISABLED
-When:	2.6.36
-Why:	The flag is a NOOP as we run interrupt handlers with interrupts disabled
-Who:	Thomas Gleixner <tglx@linutronix.de>
-
-----------------------------
-
-What: 	PCI DMA unmap state API
-When:	August 2012
-Why:	PCI DMA unmap state API (include/linux/pci-dma.h) was replaced
-	with DMA unmap state API (DMA unmap state API can be used for
-	any bus).
-Who:	FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
-
-----------------------------
-
-What:	iwlwifi disable_hw_scan module parameters
-When:	3.0
-Why:	Hareware scan is the prefer method for iwlwifi devices for
-	scanning operation. Remove software scan support for all the
-	iwlwifi devices.
-
-Who:	Wey-Yi Guy <wey-yi.w.guy@intel.com>
-
-----------------------------
-
-What:	i2c_driver.attach_adapter
-	i2c_driver.detach_adapter
-When:	September 2011
-Why:	These legacy callbacks should no longer be used as i2c-core offers
-	a variety of preferable alternative ways to instantiate I2C devices.
-Who:	Jean Delvare <khali@linux-fr.org>
-
-----------------------------
-
-What:	Opening a radio device node will no longer automatically switch the
-	tuner mode from tv to radio.
-When:	3.3
-Why:	Just opening a V4L device should not change the state of the hardware
-	like that. It's very unexpected and against the V4L spec. Instead, you
-	switch to radio mode by calling VIDIOC_S_FREQUENCY. This is the second
-	and last step of the move to consistent handling of tv and radio tuners.
-Who:	Hans Verkuil <hans.verkuil@cisco.com>
-
-----------------------------
-
-What:	CONFIG_CFG80211_WEXT
-When:	as soon as distributions ship new wireless tools, ie. wpa_supplicant 1.0
-	and NetworkManager/connman/etc. that are able to use nl80211
-Why:	Wireless extensions are deprecated, and userland tools are moving to
-	using nl80211. New drivers are no longer using wireless extensions,
-	and while there might still be old drivers, both new drivers and new
-	userland no longer needs them and they can't be used for an feature
-	developed in the past couple of years. As such, compatibility with
-	wireless extensions in new drivers will be removed.
-Who:	Johannes Berg <johannes@sipsolutions.net>
-
-----------------------------
-
-What:	g_file_storage driver
-When:	3.8
-Why:	This driver has been superseded by g_mass_storage.
-Who:	Alan Stern <stern@rowland.harvard.edu>
-
-----------------------------
-
-What:   threeg and interface sysfs files in /sys/devices/platform/acer-wmi
-When:   2012
-Why:    In 3.0, we can now autodetect internal 3G device and already have
-	the threeg rfkill device. So, we plan to remove threeg sysfs support
-	for it's no longer necessary.
-
-	We also plan to remove interface sysfs file that exposed which ACPI-WMI
-	interface that was used by acer-wmi driver. It will replaced by
-	information log when acer-wmi initial.
-Who:    Lee, Chun-Yi <jlee@novell.com>
-
----------------------------
-
-What:	/sys/devices/platform/_UDC_/udc/_UDC_/is_dualspeed file and
-	is_dualspeed line in /sys/devices/platform/ci13xxx_*/udc/device file.
-When:	3.8
-Why:	The is_dualspeed file is superseded by maximum_speed in the same
-	directory and is_dualspeed line in device file is superseded by
-	max_speed line in the same file.
-
-	The maximum_speed/max_speed specifies maximum speed supported by UDC.
-	To check if dualspeeed is supported, check if the value is >= 3.
-	Various possible speeds are defined in <linux/usb/ch9.h>.
-Who:	Michal Nazarewicz <mina86@mina86.com>
-
-----------------------------
-
-What:	The XFS nodelaylog mount option
-When:	3.3
-Why:	The delaylog mode that has been the default since 2.6.39 has proven
-	stable, and the old code is in the way of additional improvements in
-	the log code.
-Who:	Christoph Hellwig <hch@lst.de>
-
-----------------------------
-
-What:	iwlagn alias support
-When:	3.5
-Why:	The iwlagn module has been renamed iwlwifi.  The alias will be around
-	for backward compatibility for several cycles and then dropped.
-Who:	Don Fry <donald.h.fry@intel.com>
-
-----------------------------
-
-What:	pci_scan_bus_parented()
-When:	3.5
-Why:	The pci_scan_bus_parented() interface creates a new root bus.  The
-	bus is created with default resources (ioport_resource and
-	iomem_resource) that are always wrong, so we rely on arch code to
-	correct them later.  Callers of pci_scan_bus_parented() should
-	convert to using pci_scan_root_bus() so they can supply a list of
-	bus resources when the bus is created.
-Who:	Bjorn Helgaas <bhelgaas@google.com>
-
-----------------------------
-
-What:	get_robust_list syscall
-When:	2013
-Why:	There appear to be no production users of the get_robust_list syscall,
-	and it runs the risk of leaking address locations, allowing the bypass
-	of ASLR. It was only ever intended for debugging, so it should be
-	removed.
-Who:	Kees Cook <keescook@chromium.org>
-
-----------------------------
-
-What:	Removing the pn544 raw driver.
-When:	3.6
-Why:	With the introduction of the NFC HCI and SHDL kernel layers, pn544.c
-	is being replaced by pn544_hci.c which is accessible through the netlink
-	and socket NFC APIs. Moreover, pn544.c is outdated and does not seem to
-	work properly with the latest Android stacks.
-	Having 2 drivers for the same hardware is confusing and as such we
-	should only keep the one following the kernel NFC APIs.
-Who:	Samuel Ortiz <sameo@linux.intel.com>
-
-----------------------------
-
-What:	setitimer accepts user NULL pointer (value)
-When:	3.6
-Why:	setitimer is not returning -EFAULT if user pointer is NULL. This
-	violates the spec.
-Who:	Sasikantha Babu <sasikanth.v19@gmail.com>
-
-----------------------------
-
-What:	remove bogus DV presets V4L2_DV_1080I29_97, V4L2_DV_1080I30 and
-	V4L2_DV_1080I25
-When:	3.6
-Why:	These HDTV formats do not exist and were added by a confused mind
-	(that was me, to be precise...)
-Who:	Hans Verkuil <hans.verkuil@cisco.com>
-
-----------------------------
-
-What:	V4L2_CID_HCENTER, V4L2_CID_VCENTER V4L2 controls
-When:	3.7
-Why:	The V4L2_CID_VCENTER, V4L2_CID_HCENTER controls have been deprecated
-	for about 4 years and they are not used by any mainline driver.
-	There are newer controls (V4L2_CID_PAN*, V4L2_CID_TILT*) that provide
-	similar	functionality.
-Who:	Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
-
-----------------------------
-
-What:	cgroup option updates via remount
-When:	March 2013
-Why:	Remount currently allows changing bound subsystems and
-	release_agent.  Rebinding is hardly useful as it only works
-	when the hierarchy is empty and release_agent itself should be
-	replaced with conventional fsnotify.
-
-----------------------------
-
-What:  xt_recent rev 0
-When:  2013
-Who:   Pablo Neira Ayuso <pablo@netfilter.org>
-Files: net/netfilter/xt_recent.c
-
-----------------------------
-
-What:	KVM debugfs statistics
-When:	2013
-Why:	KVM tracepoints provide mostly equivalent information in a much more
-        flexible fashion.
-
-----------------------------
-
-What:	at91-mci driver ("CONFIG_MMC_AT91")
-When:	3.8
-Why:	There are two mci drivers: at91-mci and atmel-mci. The PDC support
-	was added to atmel-mci as a first step to support more chips.
-	Then at91-mci was kept only for old IP versions (on at91rm9200 and
-	at91sam9261). The support of these IP versions has just been added
-	to atmel-mci, so atmel-mci can be used for all chips.
-Who:	Ludovic Desroches <ludovic.desroches@atmel.com>
-
-----------------------------
-
-What:	net/wanrouter/
-When:	June 2013
-Why:	Unsupported/unmaintained/unused since 2.6
-
-----------------------------
-
-What:	V4L2 selections API target rectangle and flags unification, the
-	following definitions will be removed: V4L2_SEL_TGT_CROP_ACTIVE,
-	V4L2_SEL_TGT_COMPOSE_ACTIVE, V4L2_SUBDEV_SEL_*, V4L2_SUBDEV_SEL_FLAG_*
-	in favor of common V4L2_SEL_TGT_* and V4L2_SEL_FLAG_* definitions.
-	For more details see include/linux/v4l2-common.h.
-When:	3.8
-Why:	The regular V4L2 selections and the subdev selection API originally
-	defined distinct names for the target rectangles and flags - V4L2_SEL_*
-	and V4L2_SUBDEV_SEL_*. Although, it turned out that the meaning of these
-	target rectangles is virtually identical and the APIs were consolidated
-	to use single set of names - V4L2_SEL_*. This didn't involve any ABI
-	changes. Alias definitions were created for the original ones to avoid
-	any instabilities in the user space interface. After few cycles these
-	backward compatibility definitions will be removed.
-Who:	Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
-
-----------------------------
-
-What:	Using V4L2_CAP_VIDEO_CAPTURE and V4L2_CAP_VIDEO_OUTPUT flags
-	to indicate a V4L2 memory-to-memory device capability
-When:	3.8
-Why:	New drivers should use new V4L2_CAP_VIDEO_M2M capability flag
-	to indicate a V4L2 video memory-to-memory (M2M) device and
-	applications can now identify a M2M video device by checking
-	for V4L2_CAP_VIDEO_M2M, with VIDIOC_QUERYCAP ioctl. Using ORed
-	V4L2_CAP_VIDEO_CAPTURE and V4L2_CAP_VIDEO_OUTPUT flags for M2M
-	devices is ambiguous and may lead, for example, to identifying
-	a M2M device as a video	capture or output device.
-Who:	Sylwester Nawrocki <s.nawrocki@samsung.com>
-
-----------------------------
-
-What:	OMAP private DMA implementation
-When:	2013
-Why:	We have a DMA engine implementation; all users should be updated
-	to use this rather than persisting with the old APIs.  The old APIs
-	block merging the old DMA engine implementation into the DMA
-	engine driver.
-Who:	Russell King <linux@arm.linux.org.uk>,
-	Santosh Shilimkar <santosh.shilimkar@ti.com>
-
-----------------------------