Merge branch 'for-2.6.37/core' of git://git.kernel.dk/linux-2.6-block

* 'for-2.6.37/core' of git://git.kernel.dk/linux-2.6-block: (39 commits)
  cfq-iosched: Fix a gcc 4.5 warning and put some comments
  block: Turn bvec_k{un,}map_irq() into static inline functions
  block: fix accounting bug on cross partition merges
  block: Make the integrity mapped property a bio flag
  block: Fix double free in blk_integrity_unregister
  block: Ensure physical block size is unsigned int
  blkio-throttle: Fix possible multiplication overflow in iops calculations
  blkio-throttle: limit max iops value to UINT_MAX
  blkio-throttle: There is no need to convert jiffies to milli seconds
  blkio-throttle: Fix link failure failure on i386
  blkio: Recalculate the throttled bio dispatch time upon throttle limit change
  blkio: Add root group to td->tg_list
  blkio: deletion of a cgroup was causes oops
  blkio: Do not export throttle files if CONFIG_BLK_DEV_THROTTLING=n
  block: set the bounce_pfn to the actual DMA limit rather than to max memory
  block: revert bad fix for memory hotplug causing bounces
  Fix compile error in blk-exec.c for !CONFIG_DETECT_HUNG_TASK
  block: set the bounce_pfn to the actual DMA limit rather than to max memory
  block: Prevent hang_check firing during long I/O
  cfq: improve fsync performance for small files
  ...

Fix up trivial conflicts due to __rcu sparse annotation in include/linux/genhd.h

Documentation/cgroups/blkio-controller.txt

@@ -8,12 +8,17 @@ both at leaf nodes as well as at intermediate nodes in a storage hierarchy.
 Plan is to use the same cgroup based management interface for blkio controller
 and based on user options switch IO policies in the background.
 
-In the first phase, this patchset implements proportional weight time based
-division of disk policy. It is implemented in CFQ. Hence this policy takes
-effect only on leaf nodes when CFQ is being used.
+Currently two IO control policies are implemented. First one is proportional
+weight time based division of disk policy. It is implemented in CFQ. Hence
+this policy takes effect only on leaf nodes when CFQ is being used. The second
+one is throttling policy which can be used to specify upper IO rate limits
+on devices. This policy is implemented in generic block layer and can be
+used on leaf nodes as well as higher level logical devices like device mapper.
 
 HOWTO
 =====
+Proportional Weight division of bandwidth
+-----------------------------------------
 You can do a very simple testing of running two dd threads in two different
 cgroups. Here is what you can do.
 
@@ -55,6 +60,35 @@ cgroups. Here is what you can do.
   group dispatched to the disk. We provide fairness in terms of disk time, so
   ideally io.disk_time of cgroups should be in proportion to the weight.
 
+Throttling/Upper Limit policy
+-----------------------------
+- Enable Block IO controller
+	CONFIG_BLK_CGROUP=y
+
+- Enable throttling in block layer
+	CONFIG_BLK_DEV_THROTTLING=y
+
+- Mount blkio controller
+        mount -t cgroup -o blkio none /cgroup/blkio
+
+- Specify a bandwidth rate on particular device for root group. The format
+  for policy is "<major>:<minor>  <byes_per_second>".
+
+        echo "8:16  1048576" > /cgroup/blkio/blkio.read_bps_device
+
+  Above will put a limit of 1MB/second on reads happening for root group
+  on device having major/minor number 8:16.
+
+- Run dd to read a file and see if rate is throttled to 1MB/s or not.
+
+		# dd if=/mnt/common/zerofile of=/dev/null bs=4K count=1024
+		# iflag=direct
+        1024+0 records in
+        1024+0 records out
+        4194304 bytes (4.2 MB) copied, 4.0001 s, 1.0 MB/s
+
+ Limits for writes can be put using blkio.write_bps_device file.
+
 Various user visible config options
 ===================================
 CONFIG_BLK_CGROUP
@@ -68,8 +102,13 @@ CONFIG_CFQ_GROUP_IOSCHED
 	- Enables group scheduling in CFQ. Currently only 1 level of group
 	  creation is allowed.
 
+CONFIG_BLK_DEV_THROTTLING
+	- Enable block device throttling support in block layer.
+
 Details of cgroup files
 =======================
+Proportional weight policy files
+--------------------------------
 - blkio.weight
 	- Specifies per cgroup weight. This is default weight of the group
 	  on all the devices until and unless overridden by per device rule.
@@ -210,6 +249,67 @@ Details of cgroup files
 	  and minor number of the device and third field specifies the number
 	  of times a group was dequeued from a particular device.
 
+Throttling/Upper limit policy files
+-----------------------------------
+- blkio.throttle.read_bps_device
+	- Specifies upper limit on READ rate from the device. IO rate is
+	  specified in bytes per second. Rules are per deivce. Following is
+	  the format.
+
+  echo "<major>:<minor>  <rate_bytes_per_second>" > /cgrp/blkio.read_bps_device
+
+- blkio.throttle.write_bps_device
+	- Specifies upper limit on WRITE rate to the device. IO rate is
+	  specified in bytes per second. Rules are per deivce. Following is
+	  the format.
+
+  echo "<major>:<minor>  <rate_bytes_per_second>" > /cgrp/blkio.write_bps_device
+
+- blkio.throttle.read_iops_device
+	- Specifies upper limit on READ rate from the device. IO rate is
+	  specified in IO per second. Rules are per deivce. Following is
+	  the format.
+
+  echo "<major>:<minor>  <rate_io_per_second>" > /cgrp/blkio.read_iops_device
+
+- blkio.throttle.write_iops_device
+	- Specifies upper limit on WRITE rate to the device. IO rate is
+	  specified in io per second. Rules are per deivce. Following is
+	  the format.
+
+  echo "<major>:<minor>  <rate_io_per_second>" > /cgrp/blkio.write_iops_device
+
+Note: If both BW and IOPS rules are specified for a device, then IO is
+      subjectd to both the constraints.
+
+- blkio.throttle.io_serviced
+	- Number of IOs (bio) completed to/from the disk by the group (as
+	  seen by throttling policy). These are further divided by the type
+	  of operation - read or write, sync or async. First two fields specify
+	  the major and minor number of the device, third field specifies the
+	  operation type and the fourth field specifies the number of IOs.
+
+	  blkio.io_serviced does accounting as seen by CFQ and counts are in
+	  number of requests (struct request). On the other hand,
+	  blkio.throttle.io_serviced counts number of IO in terms of number
+	  of bios as seen by throttling policy.  These bios can later be
+	  merged by elevator and total number of requests completed can be
+	  lesser.
+
+- blkio.throttle.io_service_bytes
+	- Number of bytes transferred to/from the disk by the group. These
+	  are further divided by the type of operation - read or write, sync
+	  or async. First two fields specify the major and minor number of the
+	  device, third field specifies the operation type and the fourth field
+	  specifies the number of bytes.
+
+	  These numbers should roughly be same as blkio.io_service_bytes as
+	  updated by CFQ. The difference between two is that
+	  blkio.io_service_bytes will not be updated if CFQ is not operating
+	  on request queue.
+
+Common files among various policies
+-----------------------------------
 - blkio.reset_stats
 	- Writing an int to this file will result in resetting all the stats
 	  for that cgroup.

block/Kconfig

@@ -77,6 +77,18 @@ config BLK_DEV_INTEGRITY
 	T10/SCSI Data Integrity Field or the T13/ATA External Path
 	Protection.  If in doubt, say N.
 
+config BLK_DEV_THROTTLING
+	bool "Block layer bio throttling support"
+	depends on BLK_CGROUP=y && EXPERIMENTAL
+	default n
+	---help---
+	Block layer bio throttling support. It can be used to limit
+	the IO rate to a device. IO rate policies are per cgroup and
+	one needs to mount and use blkio cgroup controller for creating
+	cgroups and specifying per device IO rate policies.
+
+	See Documentation/cgroups/blkio-controller.txt for more information.
+
 endif # BLOCK
 
 config BLOCK_COMPAT

block/Makefile

@@ -9,6 +9,7 @@ obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o \
 
 obj-$(CONFIG_BLK_DEV_BSG)	+= bsg.o
 obj-$(CONFIG_BLK_CGROUP)	+= blk-cgroup.o
+obj-$(CONFIG_BLK_DEV_THROTTLING)	+= blk-throttle.o
 obj-$(CONFIG_IOSCHED_NOOP)	+= noop-iosched.o
 obj-$(CONFIG_IOSCHED_DEADLINE)	+= deadline-iosched.o
 obj-$(CONFIG_IOSCHED_CFQ)	+= cfq-iosched.o

block/blk-cgroup.c

@@ -37,6 +37,12 @@ static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *,
 static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *);
 static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *);
 
+/* for encoding cft->private value on file */
+#define BLKIOFILE_PRIVATE(x, val)	(((x) << 16) | (val))
+/* What policy owns the file, proportional or throttle */
+#define BLKIOFILE_POLICY(val)		(((val) >> 16) & 0xffff)
+#define BLKIOFILE_ATTR(val)		((val) & 0xffff)
+
 struct cgroup_subsys blkio_subsys = {
 	.name = "blkio",
 	.create = blkiocg_create,
@@ -59,6 +65,27 @@ static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg,
 	list_add(&pn->node, &blkcg->policy_list);
 }
 
+static inline bool cftype_blkg_same_policy(struct cftype *cft,
+			struct blkio_group *blkg)
+{
+	enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
+
+	if (blkg->plid == plid)
+		return 1;
+
+	return 0;
+}
+
+/* Determines if policy node matches cgroup file being accessed */
+static inline bool pn_matches_cftype(struct cftype *cft,
+			struct blkio_policy_node *pn)
+{
+	enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
+	int fileid = BLKIOFILE_ATTR(cft->private);
+
+	return (plid == pn->plid && fileid == pn->fileid);
+}
+
 /* Must be called with blkcg->lock held */
 static inline void blkio_policy_delete_node(struct blkio_policy_node *pn)
 {
@@ -67,12 +94,13 @@ static inline void blkio_policy_delete_node(struct blkio_policy_node *pn)
 
 /* Must be called with blkcg->lock held */
 static struct blkio_policy_node *
-blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev)
+blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev,
+		enum blkio_policy_id plid, int fileid)
 {
 	struct blkio_policy_node *pn;
 
 	list_for_each_entry(pn, &blkcg->policy_list, node) {
-		if (pn->dev == dev)
+		if (pn->dev == dev && pn->plid == plid && pn->fileid == fileid)
 			return pn;
 	}
 
@@ -86,6 +114,67 @@ struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
 }
 EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
 
+static inline void
+blkio_update_group_weight(struct blkio_group *blkg, unsigned int weight)
+{
+	struct blkio_policy_type *blkiop;
+
+	list_for_each_entry(blkiop, &blkio_list, list) {
+		/* If this policy does not own the blkg, do not send updates */
+		if (blkiop->plid != blkg->plid)
+			continue;
+		if (blkiop->ops.blkio_update_group_weight_fn)
+			blkiop->ops.blkio_update_group_weight_fn(blkg->key,
+							blkg, weight);
+	}
+}
+
+static inline void blkio_update_group_bps(struct blkio_group *blkg, u64 bps,
+				int fileid)
+{
+	struct blkio_policy_type *blkiop;
+
+	list_for_each_entry(blkiop, &blkio_list, list) {
+
+		/* If this policy does not own the blkg, do not send updates */
+		if (blkiop->plid != blkg->plid)
+			continue;
+
+		if (fileid == BLKIO_THROTL_read_bps_device
+		    && blkiop->ops.blkio_update_group_read_bps_fn)
+			blkiop->ops.blkio_update_group_read_bps_fn(blkg->key,
+								blkg, bps);
+
+		if (fileid == BLKIO_THROTL_write_bps_device
+		    && blkiop->ops.blkio_update_group_write_bps_fn)
+			blkiop->ops.blkio_update_group_write_bps_fn(blkg->key,
+								blkg, bps);
+	}
+}
+
+static inline void blkio_update_group_iops(struct blkio_group *blkg,
+			unsigned int iops, int fileid)
+{
+	struct blkio_policy_type *blkiop;
+
+	list_for_each_entry(blkiop, &blkio_list, list) {
+
+		/* If this policy does not own the blkg, do not send updates */
+		if (blkiop->plid != blkg->plid)
+			continue;
+
+		if (fileid == BLKIO_THROTL_read_iops_device
+		    && blkiop->ops.blkio_update_group_read_iops_fn)
+			blkiop->ops.blkio_update_group_read_iops_fn(blkg->key,
+								blkg, iops);
+
+		if (fileid == BLKIO_THROTL_write_iops_device
+		    && blkiop->ops.blkio_update_group_write_iops_fn)
+			blkiop->ops.blkio_update_group_write_iops_fn(blkg->key,
+								blkg,iops);
+	}
+}
+
 /*
  * Add to the appropriate stat variable depending on the request type.
  * This should be called with the blkg->stats_lock held.
@@ -341,7 +430,8 @@ void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
 EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
 
 void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
-			struct blkio_group *blkg, void *key, dev_t dev)
+		struct blkio_group *blkg, void *key, dev_t dev,
+		enum blkio_policy_id plid)
 {
 	unsigned long flags;
 
@@ -350,6 +440,7 @@ void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
 	rcu_assign_pointer(blkg->key, key);
 	blkg->blkcg_id = css_id(&blkcg->css);
 	hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
+	blkg->plid = plid;
 	spin_unlock_irqrestore(&blkcg->lock, flags);
 	/* Need to take css reference ? */
 	cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
@@ -408,51 +499,6 @@ struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)
 }
 EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
 
-#define SHOW_FUNCTION(__VAR)						\
-static u64 blkiocg_##__VAR##_read(struct cgroup *cgroup,		\
-				       struct cftype *cftype)		\
-{									\
-	struct blkio_cgroup *blkcg;					\
-									\
-	blkcg = cgroup_to_blkio_cgroup(cgroup);				\
-	return (u64)blkcg->__VAR;					\
-}
-
-SHOW_FUNCTION(weight);
-#undef SHOW_FUNCTION
-
-static int
-blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
-{
-	struct blkio_cgroup *blkcg;
-	struct blkio_group *blkg;
-	struct hlist_node *n;
-	struct blkio_policy_type *blkiop;
-	struct blkio_policy_node *pn;
-
-	if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
-		return -EINVAL;
-
-	blkcg = cgroup_to_blkio_cgroup(cgroup);
-	spin_lock(&blkio_list_lock);
-	spin_lock_irq(&blkcg->lock);
-	blkcg->weight = (unsigned int)val;
-
-	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
-		pn = blkio_policy_search_node(blkcg, blkg->dev);
-
-		if (pn)
-			continue;
-
-		list_for_each_entry(blkiop, &blkio_list, list)
-			blkiop->ops.blkio_update_group_weight_fn(blkg,
-					blkcg->weight);
-	}
-	spin_unlock_irq(&blkcg->lock);
-	spin_unlock(&blkio_list_lock);
-	return 0;
-}
-
 static int
 blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
 {
@@ -593,52 +639,6 @@ static uint64_t blkio_get_stat(struct blkio_group *blkg,
 	return disk_total;
 }
 
-#define SHOW_FUNCTION_PER_GROUP(__VAR, type, show_total)		\
-static int blkiocg_##__VAR##_read(struct cgroup *cgroup,		\
-		struct cftype *cftype, struct cgroup_map_cb *cb)	\
-{									\
-	struct blkio_cgroup *blkcg;					\
-	struct blkio_group *blkg;					\
-	struct hlist_node *n;						\
-	uint64_t cgroup_total = 0;					\
-									\
-	if (!cgroup_lock_live_group(cgroup))				\
-		return -ENODEV;						\
-									\
-	blkcg = cgroup_to_blkio_cgroup(cgroup);				\
-	rcu_read_lock();						\
-	hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\
-		if (blkg->dev) {					\
-			spin_lock_irq(&blkg->stats_lock);		\
-			cgroup_total += blkio_get_stat(blkg, cb,	\
-						blkg->dev, type);	\
-			spin_unlock_irq(&blkg->stats_lock);		\
-		}							\
-	}								\
-	if (show_total)							\
-		cb->fill(cb, "Total", cgroup_total);			\
-	rcu_read_unlock();						\
-	cgroup_unlock();						\
-	return 0;							\
-}
-
-SHOW_FUNCTION_PER_GROUP(time, BLKIO_STAT_TIME, 0);
-SHOW_FUNCTION_PER_GROUP(sectors, BLKIO_STAT_SECTORS, 0);
-SHOW_FUNCTION_PER_GROUP(io_service_bytes, BLKIO_STAT_SERVICE_BYTES, 1);
-SHOW_FUNCTION_PER_GROUP(io_serviced, BLKIO_STAT_SERVICED, 1);
-SHOW_FUNCTION_PER_GROUP(io_service_time, BLKIO_STAT_SERVICE_TIME, 1);
-SHOW_FUNCTION_PER_GROUP(io_wait_time, BLKIO_STAT_WAIT_TIME, 1);
-SHOW_FUNCTION_PER_GROUP(io_merged, BLKIO_STAT_MERGED, 1);
-SHOW_FUNCTION_PER_GROUP(io_queued, BLKIO_STAT_QUEUED, 1);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-SHOW_FUNCTION_PER_GROUP(dequeue, BLKIO_STAT_DEQUEUE, 0);
-SHOW_FUNCTION_PER_GROUP(avg_queue_size, BLKIO_STAT_AVG_QUEUE_SIZE, 0);
-SHOW_FUNCTION_PER_GROUP(group_wait_time, BLKIO_STAT_GROUP_WAIT_TIME, 0);
-SHOW_FUNCTION_PER_GROUP(idle_time, BLKIO_STAT_IDLE_TIME, 0);
-SHOW_FUNCTION_PER_GROUP(empty_time, BLKIO_STAT_EMPTY_TIME, 0);
-#endif
-#undef SHOW_FUNCTION_PER_GROUP
-
 static int blkio_check_dev_num(dev_t dev)
 {
 	int part = 0;
@@ -652,13 +652,14 @@ static int blkio_check_dev_num(dev_t dev)
 }
 
 static int blkio_policy_parse_and_set(char *buf,
-				      struct blkio_policy_node *newpn)
+	struct blkio_policy_node *newpn, enum blkio_policy_id plid, int fileid)
 {
 	char *s[4], *p, *major_s = NULL, *minor_s = NULL;
 	int ret;
 	unsigned long major, minor, temp;
 	int i = 0;
 	dev_t dev;
+	u64 bps, iops;
 
 	memset(s, 0, sizeof(s));
 
@@ -705,12 +706,47 @@ static int blkio_policy_parse_and_set(char *buf,
 	if (s[1] == NULL)
 		return -EINVAL;
 
-	ret = strict_strtoul(s[1], 10, &temp);
-	if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||
-	    temp > BLKIO_WEIGHT_MAX)
-		return -EINVAL;
+	switch (plid) {
+	case BLKIO_POLICY_PROP:
+		ret = strict_strtoul(s[1], 10, &temp);
+		if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||
+			temp > BLKIO_WEIGHT_MAX)
+			return -EINVAL;
 
-	newpn->weight =  temp;
+		newpn->plid = plid;
+		newpn->fileid = fileid;
+		newpn->val.weight = temp;
+		break;
+	case BLKIO_POLICY_THROTL:
+		switch(fileid) {
+		case BLKIO_THROTL_read_bps_device:
+		case BLKIO_THROTL_write_bps_device:
+			ret = strict_strtoull(s[1], 10, &bps);
+			if (ret)
+				return -EINVAL;
+
+			newpn->plid = plid;
+			newpn->fileid = fileid;
+			newpn->val.bps = bps;
+			break;
+		case BLKIO_THROTL_read_iops_device:
+		case BLKIO_THROTL_write_iops_device:
+			ret = strict_strtoull(s[1], 10, &iops);
+			if (ret)
+				return -EINVAL;
+
+			if (iops > THROTL_IOPS_MAX)
+				return -EINVAL;
+
+			newpn->plid = plid;
+			newpn->fileid = fileid;
+			newpn->val.iops = (unsigned int)iops;
+			break;
+		}
+		break;
+	default:
+		BUG();
+	}
 
 	return 0;
 }
@@ -720,26 +756,180 @@ unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
 {
 	struct blkio_policy_node *pn;
 
-	pn = blkio_policy_search_node(blkcg, dev);
+	pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_PROP,
+				BLKIO_PROP_weight_device);
 	if (pn)
-		return pn->weight;
+		return pn->val.weight;
 	else
 		return blkcg->weight;
 }
 EXPORT_SYMBOL_GPL(blkcg_get_weight);
 
+uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg, dev_t dev)
+{
+	struct blkio_policy_node *pn;
+
+	pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
+				BLKIO_THROTL_read_bps_device);
+	if (pn)
+		return pn->val.bps;
+	else
+		return -1;
+}
+
+uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg, dev_t dev)
+{
+	struct blkio_policy_node *pn;
+	pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
+				BLKIO_THROTL_write_bps_device);
+	if (pn)
+		return pn->val.bps;
+	else
+		return -1;
+}
+
+unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, dev_t dev)
+{
+	struct blkio_policy_node *pn;
+
+	pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
+				BLKIO_THROTL_read_iops_device);
+	if (pn)
+		return pn->val.iops;
+	else
+		return -1;
+}
+
+unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg, dev_t dev)
+{
+	struct blkio_policy_node *pn;
+	pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
+				BLKIO_THROTL_write_iops_device);
+	if (pn)
+		return pn->val.iops;
+	else
+		return -1;
+}
+
+/* Checks whether user asked for deleting a policy rule */
+static bool blkio_delete_rule_command(struct blkio_policy_node *pn)
+{
+	switch(pn->plid) {
+	case BLKIO_POLICY_PROP:
+		if (pn->val.weight == 0)
+			return 1;
+		break;
+	case BLKIO_POLICY_THROTL:
+		switch(pn->fileid) {
+		case BLKIO_THROTL_read_bps_device:
+		case BLKIO_THROTL_write_bps_device:
+			if (pn->val.bps == 0)
+				return 1;
+			break;
+		case BLKIO_THROTL_read_iops_device:
+		case BLKIO_THROTL_write_iops_device:
+			if (pn->val.iops == 0)
+				return 1;
+		}
+		break;
+	default:
+		BUG();
+	}
+
+	return 0;
+}
+
+static void blkio_update_policy_rule(struct blkio_policy_node *oldpn,
+					struct blkio_policy_node *newpn)
+{
+	switch(oldpn->plid) {
+	case BLKIO_POLICY_PROP:
+		oldpn->val.weight = newpn->val.weight;
+		break;
+	case BLKIO_POLICY_THROTL:
+		switch(newpn->fileid) {
+		case BLKIO_THROTL_read_bps_device:
+		case BLKIO_THROTL_write_bps_device:
+			oldpn->val.bps = newpn->val.bps;
+			break;
+		case BLKIO_THROTL_read_iops_device:
+		case BLKIO_THROTL_write_iops_device:
+			oldpn->val.iops = newpn->val.iops;
+		}
+		break;
+	default:
+		BUG();
+	}
+}
+
+/*
+ * Some rules/values in blkg have changed. Propogate those to respective
+ * policies.
+ */
+static void blkio_update_blkg_policy(struct blkio_cgroup *blkcg,
+		struct blkio_group *blkg, struct blkio_policy_node *pn)
+{
+	unsigned int weight, iops;
+	u64 bps;
+
+	switch(pn->plid) {
+	case BLKIO_POLICY_PROP:
+		weight = pn->val.weight ? pn->val.weight :
+				blkcg->weight;
+		blkio_update_group_weight(blkg, weight);
+		break;
+	case BLKIO_POLICY_THROTL:
+		switch(pn->fileid) {
+		case BLKIO_THROTL_read_bps_device:
+		case BLKIO_THROTL_write_bps_device:
+			bps = pn->val.bps ? pn->val.bps : (-1);
+			blkio_update_group_bps(blkg, bps, pn->fileid);
+			break;
+		case BLKIO_THROTL_read_iops_device:
+		case BLKIO_THROTL_write_iops_device:
+			iops = pn->val.iops ? pn->val.iops : (-1);
+			blkio_update_group_iops(blkg, iops, pn->fileid);
+			break;
+		}
+		break;
+	default:
+		BUG();
+	}
+}
+
+/*
+ * A policy node rule has been updated. Propogate this update to all the
+ * block groups which might be affected by this update.
+ */
+static void blkio_update_policy_node_blkg(struct blkio_cgroup *blkcg,
+				struct blkio_policy_node *pn)
+{
+	struct blkio_group *blkg;
+	struct hlist_node *n;
+
+	spin_lock(&blkio_list_lock);
+	spin_lock_irq(&blkcg->lock);
+
+	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
+		if (pn->dev != blkg->dev || pn->plid != blkg->plid)
+			continue;
+		blkio_update_blkg_policy(blkcg, blkg, pn);
+	}
+
+	spin_unlock_irq(&blkcg->lock);
+	spin_unlock(&blkio_list_lock);
+}
 
-static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft,
-				       const char *buffer)
+static int blkiocg_file_write(struct cgroup *cgrp, struct cftype *cft,
+ 				       const char *buffer)
 {
 	int ret = 0;
 	char *buf;
 	struct blkio_policy_node *newpn, *pn;
 	struct blkio_cgroup *blkcg;
-	struct blkio_group *blkg;
 	int keep_newpn = 0;
-	struct hlist_node *n;
-	struct blkio_policy_type *blkiop;
+	enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
+	int fileid = BLKIOFILE_ATTR(cft->private);
 
 	buf = kstrdup(buffer, GFP_KERNEL);
 	if (!buf)
@@ -751,7 +941,7 @@ static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft,
 		goto free_buf;
 	}
 
-	ret = blkio_policy_parse_and_set(buf, newpn);
+	ret = blkio_policy_parse_and_set(buf, newpn, plid, fileid);
 	if (ret)
 		goto free_newpn;
 
@@ -759,9 +949,9 @@ static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft,
 
 	spin_lock_irq(&blkcg->lock);
 
-	pn = blkio_policy_search_node(blkcg, newpn->dev);
+	pn = blkio_policy_search_node(blkcg, newpn->dev, plid, fileid);
 	if (!pn) {
-		if (newpn->weight != 0) {
+		if (!blkio_delete_rule_command(newpn)) {
 			blkio_policy_insert_node(blkcg, newpn);
 			keep_newpn = 1;
 		}
@@ -769,33 +959,17 @@ static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft,
 		goto update_io_group;
 	}
 
-	if (newpn->weight == 0) {
-		/* weight == 0 means deleteing a specific weight */
+	if (blkio_delete_rule_command(newpn)) {
 		blkio_policy_delete_node(pn);
 		spin_unlock_irq(&blkcg->lock);
 		goto update_io_group;
 	}
 	spin_unlock_irq(&blkcg->lock);
 
-	pn->weight = newpn->weight;
+	blkio_update_policy_rule(pn, newpn);
 
 update_io_group:
-	/* update weight for each cfqg */
-	spin_lock(&blkio_list_lock);
-	spin_lock_irq(&blkcg->lock);
-
-	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
-		if (newpn->dev == blkg->dev) {
-			list_for_each_entry(blkiop, &blkio_list, list)
-				blkiop->ops.blkio_update_group_weight_fn(blkg,
-							 newpn->weight ?
-							 newpn->weight :
-							 blkcg->weight);
-		}
-	}
-
-	spin_unlock_irq(&blkcg->lock);
-	spin_unlock(&blkio_list_lock);
+	blkio_update_policy_node_blkg(blkcg, newpn);
 
 free_newpn:
 	if (!keep_newpn)
@@ -805,23 +979,256 @@ free_buf:
 	return ret;
 }
 
-static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft,
-				      struct seq_file *m)
+static void
+blkio_print_policy_node(struct seq_file *m, struct blkio_policy_node *pn)
 {
-	struct blkio_cgroup *blkcg;
-	struct blkio_policy_node *pn;
+	switch(pn->plid) {
+		case BLKIO_POLICY_PROP:
+			if (pn->fileid == BLKIO_PROP_weight_device)
+				seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
+					MINOR(pn->dev), pn->val.weight);
+			break;
+		case BLKIO_POLICY_THROTL:
+			switch(pn->fileid) {
+			case BLKIO_THROTL_read_bps_device:
+			case BLKIO_THROTL_write_bps_device:
+				seq_printf(m, "%u:%u\t%llu\n", MAJOR(pn->dev),
+					MINOR(pn->dev), pn->val.bps);
+				break;
+			case BLKIO_THROTL_read_iops_device:
+			case BLKIO_THROTL_write_iops_device:
+				seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
+					MINOR(pn->dev), pn->val.iops);
+				break;
+			}
+			break;
+		default:
+			BUG();
+	}
+}
 
-	seq_printf(m, "dev\tweight\n");
+/* cgroup files which read their data from policy nodes end up here */
+static void blkio_read_policy_node_files(struct cftype *cft,
+			struct blkio_cgroup *blkcg, struct seq_file *m)
+{
+	struct blkio_policy_node *pn;
 
-	blkcg = cgroup_to_blkio_cgroup(cgrp);
 	if (!list_empty(&blkcg->policy_list)) {
 		spin_lock_irq(&blkcg->lock);
 		list_for_each_entry(pn, &blkcg->policy_list, node) {
-			seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
-				   MINOR(pn->dev), pn->weight);
+			if (!pn_matches_cftype(cft, pn))
+				continue;
+			blkio_print_policy_node(m, pn);
 		}
 		spin_unlock_irq(&blkcg->lock);
 	}
+}
+
+static int blkiocg_file_read(struct cgroup *cgrp, struct cftype *cft,
+				struct seq_file *m)
+{
+	struct blkio_cgroup *blkcg;
+	enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
+	int name = BLKIOFILE_ATTR(cft->private);
+
+	blkcg = cgroup_to_blkio_cgroup(cgrp);
+
+	switch(plid) {
+	case BLKIO_POLICY_PROP:
+		switch(name) {
+		case BLKIO_PROP_weight_device:
+			blkio_read_policy_node_files(cft, blkcg, m);
+			return 0;
+		default:
+			BUG();
+		}
+		break;
+	case BLKIO_POLICY_THROTL:
+		switch(name){
+		case BLKIO_THROTL_read_bps_device:
+		case BLKIO_THROTL_write_bps_device:
+		case BLKIO_THROTL_read_iops_device:
+		case BLKIO_THROTL_write_iops_device:
+			blkio_read_policy_node_files(cft, blkcg, m);
+			return 0;
+		default:
+			BUG();
+		}
+		break;
+	default:
+		BUG();
+	}
+
+	return 0;
+}
+
+static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg,
+		struct cftype *cft, struct cgroup_map_cb *cb, enum stat_type type,
+		bool show_total)
+{
+	struct blkio_group *blkg;
+	struct hlist_node *n;
+	uint64_t cgroup_total = 0;
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
+		if (blkg->dev) {
+			if (!cftype_blkg_same_policy(cft, blkg))
+				continue;
+			spin_lock_irq(&blkg->stats_lock);
+			cgroup_total += blkio_get_stat(blkg, cb, blkg->dev,
+						type);
+			spin_unlock_irq(&blkg->stats_lock);
+		}
+	}
+	if (show_total)
+		cb->fill(cb, "Total", cgroup_total);
+	rcu_read_unlock();
+	return 0;
+}
+
+/* All map kind of cgroup file get serviced by this function */
+static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft,
+				struct cgroup_map_cb *cb)
+{
+	struct blkio_cgroup *blkcg;
+	enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
+	int name = BLKIOFILE_ATTR(cft->private);
+
+	blkcg = cgroup_to_blkio_cgroup(cgrp);
+
+	switch(plid) {
+	case BLKIO_POLICY_PROP:
+		switch(name) {
+		case BLKIO_PROP_time:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_TIME, 0);
+		case BLKIO_PROP_sectors:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_SECTORS, 0);
+		case BLKIO_PROP_io_service_bytes:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_SERVICE_BYTES, 1);
+		case BLKIO_PROP_io_serviced:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_SERVICED, 1);
+		case BLKIO_PROP_io_service_time:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_SERVICE_TIME, 1);
+		case BLKIO_PROP_io_wait_time:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_WAIT_TIME, 1);
+		case BLKIO_PROP_io_merged:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_MERGED, 1);
+		case BLKIO_PROP_io_queued:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_QUEUED, 1);
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+		case BLKIO_PROP_dequeue:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_DEQUEUE, 0);
+		case BLKIO_PROP_avg_queue_size:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_AVG_QUEUE_SIZE, 0);
+		case BLKIO_PROP_group_wait_time:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_GROUP_WAIT_TIME, 0);
+		case BLKIO_PROP_idle_time:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_IDLE_TIME, 0);
+		case BLKIO_PROP_empty_time:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_EMPTY_TIME, 0);
+#endif
+		default:
+			BUG();
+		}
+		break;
+	case BLKIO_POLICY_THROTL:
+		switch(name){
+		case BLKIO_THROTL_io_service_bytes:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_SERVICE_BYTES, 1);
+		case BLKIO_THROTL_io_serviced:
+			return blkio_read_blkg_stats(blkcg, cft, cb,
+						BLKIO_STAT_SERVICED, 1);
+		default:
+			BUG();
+		}
+		break;
+	default:
+		BUG();
+	}
+
+	return 0;
+}
+
+static int blkio_weight_write(struct blkio_cgroup *blkcg, u64 val)
+{
+	struct blkio_group *blkg;
+	struct hlist_node *n;
+	struct blkio_policy_node *pn;
+
+	if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
+		return -EINVAL;
+
+	spin_lock(&blkio_list_lock);
+	spin_lock_irq(&blkcg->lock);
+	blkcg->weight = (unsigned int)val;
+
+	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
+		pn = blkio_policy_search_node(blkcg, blkg->dev,
+				BLKIO_POLICY_PROP, BLKIO_PROP_weight_device);
+		if (pn)
+			continue;
+
+		blkio_update_group_weight(blkg, blkcg->weight);
+	}
+	spin_unlock_irq(&blkcg->lock);
+	spin_unlock(&blkio_list_lock);
+	return 0;
+}
+
+static u64 blkiocg_file_read_u64 (struct cgroup *cgrp, struct cftype *cft) {
+	struct blkio_cgroup *blkcg;
+	enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
+	int name = BLKIOFILE_ATTR(cft->private);
+
+	blkcg = cgroup_to_blkio_cgroup(cgrp);
+
+	switch(plid) {
+	case BLKIO_POLICY_PROP:
+		switch(name) {
+		case BLKIO_PROP_weight:
+			return (u64)blkcg->weight;
+		}
+		break;
+	default:
+		BUG();
+	}
+	return 0;
+}
+
+static int
+blkiocg_file_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
+{
+	struct blkio_cgroup *blkcg;
+	enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
+	int name = BLKIOFILE_ATTR(cft->private);
+
+	blkcg = cgroup_to_blkio_cgroup(cgrp);
+
+	switch(plid) {
+	case BLKIO_POLICY_PROP:
+		switch(name) {
+		case BLKIO_PROP_weight:
+			return blkio_weight_write(blkcg, val);
+		}
+		break;
+	default:
+		BUG();
+	}
 
 	return 0;
 }
@@ -829,71 +1236,151 @@ static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft,
 struct cftype blkio_files[] = {
 	{
 		.name = "weight_device",
-		.read_seq_string = blkiocg_weight_device_read,
-		.write_string = blkiocg_weight_device_write,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_weight_device),
+		.read_seq_string = blkiocg_file_read,
+		.write_string = blkiocg_file_write,
 		.max_write_len = 256,
 	},
 	{
 		.name = "weight",
-		.read_u64 = blkiocg_weight_read,
-		.write_u64 = blkiocg_weight_write,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_weight),
+		.read_u64 = blkiocg_file_read_u64,
+		.write_u64 = blkiocg_file_write_u64,
 	},
 	{
 		.name = "time",
-		.read_map = blkiocg_time_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_time),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "sectors",
-		.read_map = blkiocg_sectors_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_sectors),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "io_service_bytes",
-		.read_map = blkiocg_io_service_bytes_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_io_service_bytes),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "io_serviced",
-		.read_map = blkiocg_io_serviced_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_io_serviced),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "io_service_time",
-		.read_map = blkiocg_io_service_time_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_io_service_time),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "io_wait_time",
-		.read_map = blkiocg_io_wait_time_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_io_wait_time),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "io_merged",
-		.read_map = blkiocg_io_merged_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_io_merged),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "io_queued",
-		.read_map = blkiocg_io_queued_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_io_queued),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "reset_stats",
 		.write_u64 = blkiocg_reset_stats,
 	},
+#ifdef CONFIG_BLK_DEV_THROTTLING
+	{
+		.name = "throttle.read_bps_device",
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
+				BLKIO_THROTL_read_bps_device),
+		.read_seq_string = blkiocg_file_read,
+		.write_string = blkiocg_file_write,
+		.max_write_len = 256,
+	},
+
+	{
+		.name = "throttle.write_bps_device",
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
+				BLKIO_THROTL_write_bps_device),
+		.read_seq_string = blkiocg_file_read,
+		.write_string = blkiocg_file_write,
+		.max_write_len = 256,
+	},
+
+	{
+		.name = "throttle.read_iops_device",
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
+				BLKIO_THROTL_read_iops_device),
+		.read_seq_string = blkiocg_file_read,
+		.write_string = blkiocg_file_write,
+		.max_write_len = 256,
+	},
+
+	{
+		.name = "throttle.write_iops_device",
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
+				BLKIO_THROTL_write_iops_device),
+		.read_seq_string = blkiocg_file_read,
+		.write_string = blkiocg_file_write,
+		.max_write_len = 256,
+	},
+	{
+		.name = "throttle.io_service_bytes",
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
+				BLKIO_THROTL_io_service_bytes),
+		.read_map = blkiocg_file_read_map,
+	},
+	{
+		.name = "throttle.io_serviced",
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
+				BLKIO_THROTL_io_serviced),
+		.read_map = blkiocg_file_read_map,
+	},
+#endif /* CONFIG_BLK_DEV_THROTTLING */
+
 #ifdef CONFIG_DEBUG_BLK_CGROUP
 	{
 		.name = "avg_queue_size",
-		.read_map = blkiocg_avg_queue_size_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_avg_queue_size),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "group_wait_time",
-		.read_map = blkiocg_group_wait_time_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_group_wait_time),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "idle_time",
-		.read_map = blkiocg_idle_time_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_idle_time),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "empty_time",
-		.read_map = blkiocg_empty_time_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_empty_time),
+		.read_map = blkiocg_file_read_map,
 	},
 	{
 		.name = "dequeue",
-		.read_map = blkiocg_dequeue_read,
+		.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+				BLKIO_PROP_dequeue),
+		.read_map = blkiocg_file_read_map,
 	},
 #endif
 };
@@ -932,13 +1419,14 @@ static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
 		/*
 		 * This blkio_group is being unlinked as associated cgroup is
 		 * going away. Let all the IO controlling policies know about
-		 * this event. Currently this is static call to one io
-		 * controlling policy. Once we have more policies in place, we
-		 * need some dynamic registration of callback function.
+		 * this event.
 		 */
 		spin_lock(&blkio_list_lock);
-		list_for_each_entry(blkiop, &blkio_list, list)
+		list_for_each_entry(blkiop, &blkio_list, list) {
+			if (blkiop->plid != blkg->plid)
+				continue;
 			blkiop->ops.blkio_unlink_group_fn(key, blkg);
+		}
 		spin_unlock(&blkio_list_lock);
 	} while (1);
 

block/blk-cgroup.h

@@ -15,6 +15,14 @@
 
 #include <linux/cgroup.h>
 
+enum blkio_policy_id {
+	BLKIO_POLICY_PROP = 0,		/* Proportional Bandwidth division */
+	BLKIO_POLICY_THROTL,		/* Throttling */
+};
+
+/* Max limits for throttle policy */
+#define THROTL_IOPS_MAX		UINT_MAX
+
 #if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
 
 #ifndef CONFIG_BLK_CGROUP
@@ -65,6 +73,35 @@ enum blkg_state_flags {
 	BLKG_empty,
 };
 
+/* cgroup files owned by proportional weight policy */
+enum blkcg_file_name_prop {
+	BLKIO_PROP_weight = 1,
+	BLKIO_PROP_weight_device,
+	BLKIO_PROP_io_service_bytes,
+	BLKIO_PROP_io_serviced,
+	BLKIO_PROP_time,
+	BLKIO_PROP_sectors,
+	BLKIO_PROP_io_service_time,
+	BLKIO_PROP_io_wait_time,
+	BLKIO_PROP_io_merged,
+	BLKIO_PROP_io_queued,
+	BLKIO_PROP_avg_queue_size,
+	BLKIO_PROP_group_wait_time,
+	BLKIO_PROP_idle_time,
+	BLKIO_PROP_empty_time,
+	BLKIO_PROP_dequeue,
+};
+
+/* cgroup files owned by throttle policy */
+enum blkcg_file_name_throtl {
+	BLKIO_THROTL_read_bps_device,
+	BLKIO_THROTL_write_bps_device,
+	BLKIO_THROTL_read_iops_device,
+	BLKIO_THROTL_write_iops_device,
+	BLKIO_THROTL_io_service_bytes,
+	BLKIO_THROTL_io_serviced,
+};
+
 struct blkio_cgroup {
 	struct cgroup_subsys_state css;
 	unsigned int weight;
@@ -112,6 +149,8 @@ struct blkio_group {
 	char path[128];
 	/* The device MKDEV(major, minor), this group has been created for */
 	dev_t dev;
+	/* policy which owns this blk group */
+	enum blkio_policy_id plid;
 
 	/* Need to serialize the stats in the case of reset/update */
 	spinlock_t stats_lock;
@@ -121,24 +160,60 @@ struct blkio_group {
 struct blkio_policy_node {
 	struct list_head node;
 	dev_t dev;
-	unsigned int weight;
+	/* This node belongs to max bw policy or porportional weight policy */
+	enum blkio_policy_id plid;
+	/* cgroup file to which this rule belongs to */
+	int fileid;
+
+	union {
+		unsigned int weight;
+		/*
+		 * Rate read/write in terms of byptes per second
+		 * Whether this rate represents read or write is determined
+		 * by file type "fileid".
+		 */
+		u64 bps;
+		unsigned int iops;
+	} val;
 };
 
 extern unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
 				     dev_t dev);
+extern uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg,
+				     dev_t dev);
+extern uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg,
+				     dev_t dev);
+extern unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg,
+				     dev_t dev);
+extern unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg,
+				     dev_t dev);
 
 typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
-typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
-						unsigned int weight);
+
+typedef void (blkio_update_group_weight_fn) (void *key,
+			struct blkio_group *blkg, unsigned int weight);
+typedef void (blkio_update_group_read_bps_fn) (void * key,
+			struct blkio_group *blkg, u64 read_bps);
+typedef void (blkio_update_group_write_bps_fn) (void *key,
+			struct blkio_group *blkg, u64 write_bps);
+typedef void (blkio_update_group_read_iops_fn) (void *key,
+			struct blkio_group *blkg, unsigned int read_iops);
+typedef void (blkio_update_group_write_iops_fn) (void *key,
+			struct blkio_group *blkg, unsigned int write_iops);
 
 struct blkio_policy_ops {
 	blkio_unlink_group_fn *blkio_unlink_group_fn;
 	blkio_update_group_weight_fn *blkio_update_group_weight_fn;
+	blkio_update_group_read_bps_fn *blkio_update_group_read_bps_fn;
+	blkio_update_group_write_bps_fn *blkio_update_group_write_bps_fn;
+	blkio_update_group_read_iops_fn *blkio_update_group_read_iops_fn;
+	blkio_update_group_write_iops_fn *blkio_update_group_write_iops_fn;
 };
 
 struct blkio_policy_type {
 	struct list_head list;
 	struct blkio_policy_ops ops;
+	enum blkio_policy_id plid;
 };
 
 /* Blkio controller policy registration */
@@ -212,7 +287,8 @@ static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg) {}
 extern struct blkio_cgroup blkio_root_cgroup;
 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
 extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
-			struct blkio_group *blkg, void *key, dev_t dev);
+	struct blkio_group *blkg, void *key, dev_t dev,
+	enum blkio_policy_id plid);
 extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
 extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
 						void *key);
@@ -234,7 +310,8 @@ static inline struct blkio_cgroup *
 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
 
 static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
-			struct blkio_group *blkg, void *key, dev_t dev) {}
+		struct blkio_group *blkg, void *key, dev_t dev,
+		enum blkio_policy_id plid) {}
 
 static inline int
 blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }

block/blk-core.c

@@ -64,13 +64,15 @@ static void drive_stat_acct(struct request *rq, int new_io)
 		return;
 
 	cpu = part_stat_lock();
-	part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
 
-	if (!new_io)
+	if (!new_io) {
+		part = rq->part;
 		part_stat_inc(cpu, part, merges[rw]);
-	else {
+	} else {
+		part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
 		part_round_stats(cpu, part);
 		part_inc_in_flight(part, rw);
+		rq->part = part;
 	}
 
 	part_stat_unlock();
@@ -128,6 +130,7 @@ void blk_rq_init(struct request_queue *q, struct request *rq)
 	rq->ref_count = 1;
 	rq->start_time = jiffies;
 	set_start_time_ns(rq);
+	rq->part = NULL;
 }
 EXPORT_SYMBOL(blk_rq_init);
 
@@ -382,6 +385,7 @@ void blk_sync_queue(struct request_queue *q)
 	del_timer_sync(&q->unplug_timer);
 	del_timer_sync(&q->timeout);
 	cancel_work_sync(&q->unplug_work);
+	throtl_shutdown_timer_wq(q);
 }
 EXPORT_SYMBOL(blk_sync_queue);
 
@@ -459,6 +463,8 @@ void blk_cleanup_queue(struct request_queue *q)
 	if (q->elevator)
 		elevator_exit(q->elevator);
 
+	blk_throtl_exit(q);
+
 	blk_put_queue(q);
 }
 EXPORT_SYMBOL(blk_cleanup_queue);
@@ -515,6 +521,11 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
 		return NULL;
 	}
 
+	if (blk_throtl_init(q)) {
+		kmem_cache_free(blk_requestq_cachep, q);
+		return NULL;
+	}
+
 	setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
 		    laptop_mode_timer_fn, (unsigned long) q);
 	init_timer(&q->unplug_timer);
@@ -796,11 +807,16 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
 	rl->starved[is_sync] = 0;
 
 	priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
-	if (priv)
+	if (priv) {
 		rl->elvpriv++;
 
-	if (blk_queue_io_stat(q))
-		rw_flags |= REQ_IO_STAT;
+		/*
+		 * Don't do stats for non-priv requests
+		 */
+		if (blk_queue_io_stat(q))
+			rw_flags |= REQ_IO_STAT;
+	}
+
 	spin_unlock_irq(q->queue_lock);
 
 	rq = blk_alloc_request(q, rw_flags, priv, gfp_mask);
@@ -1522,6 +1538,15 @@ static inline void __generic_make_request(struct bio *bio)
 			goto end_io;
 		}
 
+		blk_throtl_bio(q, &bio);
+
+		/*
+		 * If bio = NULL, bio has been throttled and will be submitted
+		 * later.
+		 */
+		if (!bio)
+			break;
+
 		trace_block_bio_queue(q, bio);
 
 		ret = q->make_request_fn(q, bio);
@@ -1612,11 +1637,12 @@ void submit_bio(int rw, struct bio *bio)
 
 		if (unlikely(block_dump)) {
 			char b[BDEVNAME_SIZE];
-			printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n",
+			printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n",
 			current->comm, task_pid_nr(current),
 				(rw & WRITE) ? "WRITE" : "READ",
 				(unsigned long long)bio->bi_sector,
-				bdevname(bio->bi_bdev, b));
+				bdevname(bio->bi_bdev, b),
+				count);
 		}
 	}
 
@@ -1759,7 +1785,7 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)
 		int cpu;
 
 		cpu = part_stat_lock();
-		part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+		part = req->part;
 		part_stat_add(cpu, part, sectors[rw], bytes >> 9);
 		part_stat_unlock();
 	}
@@ -1779,7 +1805,7 @@ static void blk_account_io_done(struct request *req)
 		int cpu;
 
 		cpu = part_stat_lock();
-		part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+		part = req->part;
 
 		part_stat_inc(cpu, part, ios[rw]);
 		part_stat_add(cpu, part, ticks[rw], duration);
@@ -2579,6 +2605,13 @@ int kblockd_schedule_work(struct request_queue *q, struct work_struct *work)
 }
 EXPORT_SYMBOL(kblockd_schedule_work);
 
+int kblockd_schedule_delayed_work(struct request_queue *q,
+			struct delayed_work *dwork, unsigned long delay)
+{
+	return queue_delayed_work(kblockd_workqueue, dwork, delay);
+}
+EXPORT_SYMBOL(kblockd_schedule_delayed_work);
+
 int __init blk_dev_init(void)
 {
 	BUILD_BUG_ON(__REQ_NR_BITS > 8 *

block/blk-exec.c

@@ -80,6 +80,7 @@ int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
 	DECLARE_COMPLETION_ONSTACK(wait);
 	char sense[SCSI_SENSE_BUFFERSIZE];
 	int err = 0;
+	unsigned long hang_check;
 
 	/*
 	 * we need an extra reference to the request, so we can look at
@@ -95,7 +96,13 @@ int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
 
 	rq->end_io_data = &wait;
 	blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
-	wait_for_completion(&wait);
+
+	/* Prevent hang_check timer from firing at us during very long I/O */
+	hang_check = sysctl_hung_task_timeout_secs;
+	if (hang_check)
+		while (!wait_for_completion_timeout(&wait, hang_check * (HZ/2)));
+	else
+		wait_for_completion(&wait);
 
 	if (rq->errors)
 		err = -EIO;

block/blk-integrity.c

@@ -32,24 +32,37 @@ static struct kmem_cache *integrity_cachep;
 
 /**
  * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements
- * @rq:		request with integrity metadata attached
+ * @q:		request queue
+ * @bio:	bio with integrity metadata attached
  *
  * Description: Returns the number of elements required in a
- * scatterlist corresponding to the integrity metadata in a request.
+ * scatterlist corresponding to the integrity metadata in a bio.
  */
-int blk_rq_count_integrity_sg(struct request *rq)
+int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio)
 {
-	struct bio_vec *iv, *ivprv;
-	struct req_iterator iter;
-	unsigned int segments;
+	struct bio_vec *iv, *ivprv = NULL;
+	unsigned int segments = 0;
+	unsigned int seg_size = 0;
+	unsigned int i = 0;
 
-	ivprv = NULL;
-	segments = 0;
+	bio_for_each_integrity_vec(iv, bio, i) {
 
-	rq_for_each_integrity_segment(iv, rq, iter) {
+		if (ivprv) {
+			if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv))
+				goto new_segment;
+
+			if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv))
+				goto new_segment;
 
-		if (!ivprv || !BIOVEC_PHYS_MERGEABLE(ivprv, iv))
+			if (seg_size + iv->bv_len > queue_max_segment_size(q))
+				goto new_segment;
+
+			seg_size += iv->bv_len;
+		} else {
+new_segment:
 			segments++;
+			seg_size = iv->bv_len;
+		}
 
 		ivprv = iv;
 	}
@@ -60,30 +73,34 @@ EXPORT_SYMBOL(blk_rq_count_integrity_sg);
 
 /**
  * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
- * @rq:		request with integrity metadata attached
+ * @q:		request queue
+ * @bio:	bio with integrity metadata attached
  * @sglist:	target scatterlist
  *
  * Description: Map the integrity vectors in request into a
  * scatterlist.  The scatterlist must be big enough to hold all
  * elements.  I.e. sized using blk_rq_count_integrity_sg().
  */
-int blk_rq_map_integrity_sg(struct request *rq, struct scatterlist *sglist)
+int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio,
+			    struct scatterlist *sglist)
 {
-	struct bio_vec *iv, *ivprv;
-	struct req_iterator iter;
-	struct scatterlist *sg;
-	unsigned int segments;
-
-	ivprv = NULL;
-	sg = NULL;
-	segments = 0;
+	struct bio_vec *iv, *ivprv = NULL;
+	struct scatterlist *sg = NULL;
+	unsigned int segments = 0;
+	unsigned int i = 0;
 
-	rq_for_each_integrity_segment(iv, rq, iter) {
+	bio_for_each_integrity_vec(iv, bio, i) {
 
 		if (ivprv) {
 			if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv))
 				goto new_segment;
 
+			if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv))
+				goto new_segment;
+
+			if (sg->length + iv->bv_len > queue_max_segment_size(q))
+				goto new_segment;
+
 			sg->length += iv->bv_len;
 		} else {
 new_segment:
@@ -162,6 +179,40 @@ int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2)
 }
 EXPORT_SYMBOL(blk_integrity_compare);
 
+int blk_integrity_merge_rq(struct request_queue *q, struct request *req,
+			   struct request *next)
+{
+	if (blk_integrity_rq(req) != blk_integrity_rq(next))
+		return -1;
+
+	if (req->nr_integrity_segments + next->nr_integrity_segments >
+	    q->limits.max_integrity_segments)
+		return -1;
+
+	return 0;
+}
+EXPORT_SYMBOL(blk_integrity_merge_rq);
+
+int blk_integrity_merge_bio(struct request_queue *q, struct request *req,
+			    struct bio *bio)
+{
+	int nr_integrity_segs;
+	struct bio *next = bio->bi_next;
+
+	bio->bi_next = NULL;
+	nr_integrity_segs = blk_rq_count_integrity_sg(q, bio);
+	bio->bi_next = next;
+
+	if (req->nr_integrity_segments + nr_integrity_segs >
+	    q->limits.max_integrity_segments)
+		return -1;
+
+	req->nr_integrity_segments += nr_integrity_segs;
+
+	return 0;
+}
+EXPORT_SYMBOL(blk_integrity_merge_bio);
+
 struct integrity_sysfs_entry {
 	struct attribute attr;
 	ssize_t (*show)(struct blk_integrity *, char *);
@@ -381,7 +432,6 @@ void blk_integrity_unregister(struct gendisk *disk)
 	kobject_uevent(&bi->kobj, KOBJ_REMOVE);
 	kobject_del(&bi->kobj);
 	kobject_put(&bi->kobj);
-	kmem_cache_free(integrity_cachep, bi);
 	disk->integrity = NULL;
 }
 EXPORT_SYMBOL(blk_integrity_unregister);

block/blk-map.c

@@ -54,7 +54,7 @@ static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
 	 * direct dma. else, set up kernel bounce buffers
 	 */
 	uaddr = (unsigned long) ubuf;
-	if (blk_rq_aligned(q, ubuf, len) && !map_data)
+	if (blk_rq_aligned(q, uaddr, len) && !map_data)
 		bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask);
 	else
 		bio = bio_copy_user(q, map_data, uaddr, len, reading, gfp_mask);
@@ -288,6 +288,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
 		    unsigned int len, gfp_t gfp_mask)
 {
 	int reading = rq_data_dir(rq) == READ;
+	unsigned long addr = (unsigned long) kbuf;
 	int do_copy = 0;
 	struct bio *bio;
 	int ret;
@@ -297,7 +298,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
 	if (!len || !kbuf)
 		return -EINVAL;
 
-	do_copy = !blk_rq_aligned(q, kbuf, len) || object_is_on_stack(kbuf);
+	do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
 	if (do_copy)
 		bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
 	else

block/blk-merge.c

@@ -205,12 +205,11 @@ static inline int ll_new_hw_segment(struct request_queue *q,
 {
 	int nr_phys_segs = bio_phys_segments(q, bio);
 
-	if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q)) {
-		req->cmd_flags |= REQ_NOMERGE;
-		if (req == q->last_merge)
-			q->last_merge = NULL;
-		return 0;
-	}
+	if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q))
+		goto no_merge;
+
+	if (bio_integrity(bio) && blk_integrity_merge_bio(q, req, bio))
+		goto no_merge;
 
 	/*
 	 * This will form the start of a new hw segment.  Bump both
@@ -218,6 +217,12 @@ static inline int ll_new_hw_segment(struct request_queue *q,
 	 */
 	req->nr_phys_segments += nr_phys_segs;
 	return 1;
+
+no_merge:
+	req->cmd_flags |= REQ_NOMERGE;
+	if (req == q->last_merge)
+		q->last_merge = NULL;
+	return 0;
 }
 
 int ll_back_merge_fn(struct request_queue *q, struct request *req,
@@ -301,6 +306,9 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
 	if (total_phys_segments > queue_max_segments(q))
 		return 0;
 
+	if (blk_integrity_rq(req) && blk_integrity_merge_rq(q, req, next))
+		return 0;
+
 	/* Merge is OK... */
 	req->nr_phys_segments = total_phys_segments;
 	return 1;
@@ -343,7 +351,7 @@ static void blk_account_io_merge(struct request *req)
 		int cpu;
 
 		cpu = part_stat_lock();
-		part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+		part = req->part;
 
 		part_round_stats(cpu, part);
 		part_dec_in_flight(part, rq_data_dir(req));
@@ -384,9 +392,6 @@ static int attempt_merge(struct request_queue *q, struct request *req,
 	    || next->special)
 		return 0;
 
-	if (blk_integrity_rq(req) != blk_integrity_rq(next))
-		return 0;
-
 	/*
 	 * If we are allowed to merge, then append bio list
 	 * from next to rq and release next. merge_requests_fn

block/blk-settings.c

@@ -111,6 +111,7 @@ EXPORT_SYMBOL_GPL(blk_queue_lld_busy);
 void blk_set_default_limits(struct queue_limits *lim)
 {
 	lim->max_segments = BLK_MAX_SEGMENTS;
+	lim->max_integrity_segments = 0;
 	lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
 	lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
 	lim->max_sectors = BLK_DEF_MAX_SECTORS;
@@ -213,7 +214,7 @@ void blk_queue_bounce_limit(struct request_queue *q, u64 dma_mask)
 	 */
 	if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
 		dma = 1;
-	q->limits.bounce_pfn = max_low_pfn;
+	q->limits.bounce_pfn = max(max_low_pfn, b_pfn);
 #else
 	if (b_pfn < blk_max_low_pfn)
 		dma = 1;
@@ -343,7 +344,7 @@ EXPORT_SYMBOL(blk_queue_logical_block_size);
  *   hardware can operate on without reverting to read-modify-write
  *   operations.
  */
-void blk_queue_physical_block_size(struct request_queue *q, unsigned short size)
+void blk_queue_physical_block_size(struct request_queue *q, unsigned int size)
 {
 	q->limits.physical_block_size = size;
 
@@ -455,11 +456,6 @@ void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
 }
 EXPORT_SYMBOL(blk_queue_io_opt);
 
-/*
- * Returns the minimum that is _not_ zero, unless both are zero.
- */
-#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
-
 /**
  * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
  * @t:	the stacking driver (top)
@@ -514,6 +510,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 					    b->seg_boundary_mask);
 
 	t->max_segments = min_not_zero(t->max_segments, b->max_segments);
+	t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
+						 b->max_integrity_segments);
 
 	t->max_segment_size = min_not_zero(t->max_segment_size,
 					   b->max_segment_size);

block/blk-sysfs.c

@@ -112,6 +112,11 @@ static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
 	return queue_var_show(queue_max_segments(q), (page));
 }
 
+static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(q->limits.max_integrity_segments, (page));
+}
+
 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 {
 	if (test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
@@ -288,6 +293,11 @@ static struct queue_sysfs_entry queue_max_segments_entry = {
 	.show = queue_max_segments_show,
 };
 
+static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
+	.attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
+	.show = queue_max_integrity_segments_show,
+};
+
 static struct queue_sysfs_entry queue_max_segment_size_entry = {
 	.attr = {.name = "max_segment_size", .mode = S_IRUGO },
 	.show = queue_max_segment_size_show,
@@ -375,6 +385,7 @@ static struct attribute *default_attrs[] = {
 	&queue_max_hw_sectors_entry.attr,
 	&queue_max_sectors_entry.attr,
 	&queue_max_segments_entry.attr,
+	&queue_max_integrity_segments_entry.attr,
 	&queue_max_segment_size_entry.attr,
 	&queue_iosched_entry.attr,
 	&queue_hw_sector_size_entry.attr,

block/blk-throttle.c

@@ -0,0 +1,1123 @@
+/*
+ * Interface for controlling IO bandwidth on a request queue
+ *
+ * Copyright (C) 2010 Vivek Goyal <vgoyal@redhat.com>
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/blktrace_api.h>
+#include "blk-cgroup.h"
+
+/* Max dispatch from a group in 1 round */
+static int throtl_grp_quantum = 8;
+
+/* Total max dispatch from all groups in one round */
+static int throtl_quantum = 32;
+
+/* Throttling is performed over 100ms slice and after that slice is renewed */
+static unsigned long throtl_slice = HZ/10;	/* 100 ms */
+
+struct throtl_rb_root {
+	struct rb_root rb;
+	struct rb_node *left;
+	unsigned int count;
+	unsigned long min_disptime;
+};
+
+#define THROTL_RB_ROOT	(struct throtl_rb_root) { .rb = RB_ROOT, .left = NULL, \
+			.count = 0, .min_disptime = 0}
+
+#define rb_entry_tg(node)	rb_entry((node), struct throtl_grp, rb_node)
+
+struct throtl_grp {
+	/* List of throtl groups on the request queue*/
+	struct hlist_node tg_node;
+
+	/* active throtl group service_tree member */
+	struct rb_node rb_node;
+
+	/*
+	 * Dispatch time in jiffies. This is the estimated time when group
+	 * will unthrottle and is ready to dispatch more bio. It is used as
+	 * key to sort active groups in service tree.
+	 */
+	unsigned long disptime;
+
+	struct blkio_group blkg;
+	atomic_t ref;
+	unsigned int flags;
+
+	/* Two lists for READ and WRITE */
+	struct bio_list bio_lists[2];
+
+	/* Number of queued bios on READ and WRITE lists */
+	unsigned int nr_queued[2];
+
+	/* bytes per second rate limits */
+	uint64_t bps[2];
+
+	/* IOPS limits */
+	unsigned int iops[2];
+
+	/* Number of bytes disptached in current slice */
+	uint64_t bytes_disp[2];
+	/* Number of bio's dispatched in current slice */
+	unsigned int io_disp[2];
+
+	/* When did we start a new slice */
+	unsigned long slice_start[2];
+	unsigned long slice_end[2];
+
+	/* Some throttle limits got updated for the group */
+	bool limits_changed;
+};
+
+struct throtl_data
+{
+	/* List of throtl groups */
+	struct hlist_head tg_list;
+
+	/* service tree for active throtl groups */
+	struct throtl_rb_root tg_service_tree;
+
+	struct throtl_grp root_tg;
+	struct request_queue *queue;
+
+	/* Total Number of queued bios on READ and WRITE lists */
+	unsigned int nr_queued[2];
+
+	/*
+	 * number of total undestroyed groups
+	 */
+	unsigned int nr_undestroyed_grps;
+
+	/* Work for dispatching throttled bios */
+	struct delayed_work throtl_work;
+
+	atomic_t limits_changed;
+};
+
+enum tg_state_flags {
+	THROTL_TG_FLAG_on_rr = 0,	/* on round-robin busy list */
+};
+
+#define THROTL_TG_FNS(name)						\
+static inline void throtl_mark_tg_##name(struct throtl_grp *tg)		\
+{									\
+	(tg)->flags |= (1 << THROTL_TG_FLAG_##name);			\
+}									\
+static inline void throtl_clear_tg_##name(struct throtl_grp *tg)	\
+{									\
+	(tg)->flags &= ~(1 << THROTL_TG_FLAG_##name);			\
+}									\
+static inline int throtl_tg_##name(const struct throtl_grp *tg)		\
+{									\
+	return ((tg)->flags & (1 << THROTL_TG_FLAG_##name)) != 0;	\
+}
+
+THROTL_TG_FNS(on_rr);
+
+#define throtl_log_tg(td, tg, fmt, args...)				\
+	blk_add_trace_msg((td)->queue, "throtl %s " fmt,		\
+				blkg_path(&(tg)->blkg), ##args);      	\
+
+#define throtl_log(td, fmt, args...)	\
+	blk_add_trace_msg((td)->queue, "throtl " fmt, ##args)
+
+static inline struct throtl_grp *tg_of_blkg(struct blkio_group *blkg)
+{
+	if (blkg)
+		return container_of(blkg, struct throtl_grp, blkg);
+
+	return NULL;
+}
+
+static inline int total_nr_queued(struct throtl_data *td)
+{
+	return (td->nr_queued[0] + td->nr_queued[1]);
+}
+
+static inline struct throtl_grp *throtl_ref_get_tg(struct throtl_grp *tg)
+{
+	atomic_inc(&tg->ref);
+	return tg;
+}
+
+static void throtl_put_tg(struct throtl_grp *tg)
+{
+	BUG_ON(atomic_read(&tg->ref) <= 0);
+	if (!atomic_dec_and_test(&tg->ref))
+		return;
+	kfree(tg);
+}
+
+static struct throtl_grp * throtl_find_alloc_tg(struct throtl_data *td,
+			struct cgroup *cgroup)
+{
+	struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
+	struct throtl_grp *tg = NULL;
+	void *key = td;
+	struct backing_dev_info *bdi = &td->queue->backing_dev_info;
+	unsigned int major, minor;
+
+	/*
+	 * TODO: Speed up blkiocg_lookup_group() by maintaining a radix
+	 * tree of blkg (instead of traversing through hash list all
+	 * the time.
+	 */
+	tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));
+
+	/* Fill in device details for root group */
+	if (tg && !tg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {
+		sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
+		tg->blkg.dev = MKDEV(major, minor);
+		goto done;
+	}
+
+	if (tg)
+		goto done;
+
+	tg = kzalloc_node(sizeof(*tg), GFP_ATOMIC, td->queue->node);
+	if (!tg)
+		goto done;
+
+	INIT_HLIST_NODE(&tg->tg_node);
+	RB_CLEAR_NODE(&tg->rb_node);
+	bio_list_init(&tg->bio_lists[0]);
+	bio_list_init(&tg->bio_lists[1]);
+
+	/*
+	 * Take the initial reference that will be released on destroy
+	 * This can be thought of a joint reference by cgroup and
+	 * request queue which will be dropped by either request queue
+	 * exit or cgroup deletion path depending on who is exiting first.
+	 */
+	atomic_set(&tg->ref, 1);
+
+	/* Add group onto cgroup list */
+	sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
+	blkiocg_add_blkio_group(blkcg, &tg->blkg, (void *)td,
+				MKDEV(major, minor), BLKIO_POLICY_THROTL);
+
+	tg->bps[READ] = blkcg_get_read_bps(blkcg, tg->blkg.dev);
+	tg->bps[WRITE] = blkcg_get_write_bps(blkcg, tg->blkg.dev);
+	tg->iops[READ] = blkcg_get_read_iops(blkcg, tg->blkg.dev);
+	tg->iops[WRITE] = blkcg_get_write_iops(blkcg, tg->blkg.dev);
+
+	hlist_add_head(&tg->tg_node, &td->tg_list);
+	td->nr_undestroyed_grps++;
+done:
+	return tg;
+}
+
+static struct throtl_grp * throtl_get_tg(struct throtl_data *td)
+{
+	struct cgroup *cgroup;
+	struct throtl_grp *tg = NULL;
+
+	rcu_read_lock();
+	cgroup = task_cgroup(current, blkio_subsys_id);
+	tg = throtl_find_alloc_tg(td, cgroup);
+	if (!tg)
+		tg = &td->root_tg;
+	rcu_read_unlock();
+	return tg;
+}
+
+static struct throtl_grp *throtl_rb_first(struct throtl_rb_root *root)
+{
+	/* Service tree is empty */
+	if (!root->count)
+		return NULL;
+
+	if (!root->left)
+		root->left = rb_first(&root->rb);
+
+	if (root->left)
+		return rb_entry_tg(root->left);
+
+	return NULL;
+}
+
+static void rb_erase_init(struct rb_node *n, struct rb_root *root)
+{
+	rb_erase(n, root);
+	RB_CLEAR_NODE(n);
+}
+
+static void throtl_rb_erase(struct rb_node *n, struct throtl_rb_root *root)
+{
+	if (root->left == n)
+		root->left = NULL;
+	rb_erase_init(n, &root->rb);
+	--root->count;
+}
+
+static void update_min_dispatch_time(struct throtl_rb_root *st)
+{
+	struct throtl_grp *tg;
+
+	tg = throtl_rb_first(st);
+	if (!tg)
+		return;
+
+	st->min_disptime = tg->disptime;
+}
+
+static void
+tg_service_tree_add(struct throtl_rb_root *st, struct throtl_grp *tg)
+{
+	struct rb_node **node = &st->rb.rb_node;
+	struct rb_node *parent = NULL;
+	struct throtl_grp *__tg;
+	unsigned long key = tg->disptime;
+	int left = 1;
+
+	while (*node != NULL) {
+		parent = *node;
+		__tg = rb_entry_tg(parent);
+
+		if (time_before(key, __tg->disptime))
+			node = &parent->rb_left;
+		else {
+			node = &parent->rb_right;
+			left = 0;
+		}
+	}
+
+	if (left)
+		st->left = &tg->rb_node;
+
+	rb_link_node(&tg->rb_node, parent, node);
+	rb_insert_color(&tg->rb_node, &st->rb);
+}
+
+static void __throtl_enqueue_tg(struct throtl_data *td, struct throtl_grp *tg)
+{
+	struct throtl_rb_root *st = &td->tg_service_tree;
+
+	tg_service_tree_add(st, tg);
+	throtl_mark_tg_on_rr(tg);
+	st->count++;
+}
+
+static void throtl_enqueue_tg(struct throtl_data *td, struct throtl_grp *tg)
+{
+	if (!throtl_tg_on_rr(tg))
+		__throtl_enqueue_tg(td, tg);
+}
+
+static void __throtl_dequeue_tg(struct throtl_data *td, struct throtl_grp *tg)
+{
+	throtl_rb_erase(&tg->rb_node, &td->tg_service_tree);
+	throtl_clear_tg_on_rr(tg);
+}
+
+static void throtl_dequeue_tg(struct throtl_data *td, struct throtl_grp *tg)
+{
+	if (throtl_tg_on_rr(tg))
+		__throtl_dequeue_tg(td, tg);
+}
+
+static void throtl_schedule_next_dispatch(struct throtl_data *td)
+{
+	struct throtl_rb_root *st = &td->tg_service_tree;
+
+	/*
+	 * If there are more bios pending, schedule more work.
+	 */
+	if (!total_nr_queued(td))
+		return;
+
+	BUG_ON(!st->count);
+
+	update_min_dispatch_time(st);
+
+	if (time_before_eq(st->min_disptime, jiffies))
+		throtl_schedule_delayed_work(td->queue, 0);
+	else
+		throtl_schedule_delayed_work(td->queue,
+				(st->min_disptime - jiffies));
+}
+
+static inline void
+throtl_start_new_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
+{
+	tg->bytes_disp[rw] = 0;
+	tg->io_disp[rw] = 0;
+	tg->slice_start[rw] = jiffies;
+	tg->slice_end[rw] = jiffies + throtl_slice;
+	throtl_log_tg(td, tg, "[%c] new slice start=%lu end=%lu jiffies=%lu",
+			rw == READ ? 'R' : 'W', tg->slice_start[rw],
+			tg->slice_end[rw], jiffies);
+}
+
+static inline void throtl_extend_slice(struct throtl_data *td,
+		struct throtl_grp *tg, bool rw, unsigned long jiffy_end)
+{
+	tg->slice_end[rw] = roundup(jiffy_end, throtl_slice);
+	throtl_log_tg(td, tg, "[%c] extend slice start=%lu end=%lu jiffies=%lu",
+			rw == READ ? 'R' : 'W', tg->slice_start[rw],
+			tg->slice_end[rw], jiffies);
+}
+
+/* Determine if previously allocated or extended slice is complete or not */
+static bool
+throtl_slice_used(struct throtl_data *td, struct throtl_grp *tg, bool rw)
+{
+	if (time_in_range(jiffies, tg->slice_start[rw], tg->slice_end[rw]))
+		return 0;
+
+	return 1;
+}
+
+/* Trim the used slices and adjust slice start accordingly */
+static inline void
+throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
+{
+	unsigned long nr_slices, time_elapsed, io_trim;
+	u64 bytes_trim, tmp;
+
+	BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw]));
+
+	/*
+	 * If bps are unlimited (-1), then time slice don't get
+	 * renewed. Don't try to trim the slice if slice is used. A new
+	 * slice will start when appropriate.
+	 */
+	if (throtl_slice_used(td, tg, rw))
+		return;
+
+	time_elapsed = jiffies - tg->slice_start[rw];
+
+	nr_slices = time_elapsed / throtl_slice;
+
+	if (!nr_slices)
+		return;
+	tmp = tg->bps[rw] * throtl_slice * nr_slices;
+	do_div(tmp, HZ);
+	bytes_trim = tmp;
+
+	io_trim = (tg->iops[rw] * throtl_slice * nr_slices)/HZ;
+
+	if (!bytes_trim && !io_trim)
+		return;
+
+	if (tg->bytes_disp[rw] >= bytes_trim)
+		tg->bytes_disp[rw] -= bytes_trim;
+	else
+		tg->bytes_disp[rw] = 0;
+
+	if (tg->io_disp[rw] >= io_trim)
+		tg->io_disp[rw] -= io_trim;
+	else
+		tg->io_disp[rw] = 0;
+
+	tg->slice_start[rw] += nr_slices * throtl_slice;
+
+	throtl_log_tg(td, tg, "[%c] trim slice nr=%lu bytes=%llu io=%lu"
+			" start=%lu end=%lu jiffies=%lu",
+			rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim,
+			tg->slice_start[rw], tg->slice_end[rw], jiffies);
+}
+
+static bool tg_with_in_iops_limit(struct throtl_data *td, struct throtl_grp *tg,
+		struct bio *bio, unsigned long *wait)
+{
+	bool rw = bio_data_dir(bio);
+	unsigned int io_allowed;
+	unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd;
+	u64 tmp;
+
+	jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw];
+
+	/* Slice has just started. Consider one slice interval */
+	if (!jiffy_elapsed)
+		jiffy_elapsed_rnd = throtl_slice;
+
+	jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, throtl_slice);
+
+	/*
+	 * jiffy_elapsed_rnd should not be a big value as minimum iops can be
+	 * 1 then at max jiffy elapsed should be equivalent of 1 second as we
+	 * will allow dispatch after 1 second and after that slice should
+	 * have been trimmed.
+	 */
+
+	tmp = (u64)tg->iops[rw] * jiffy_elapsed_rnd;
+	do_div(tmp, HZ);
+
+	if (tmp > UINT_MAX)
+		io_allowed = UINT_MAX;
+	else
+		io_allowed = tmp;
+
+	if (tg->io_disp[rw] + 1 <= io_allowed) {
+		if (wait)
+			*wait = 0;
+		return 1;
+	}
+
+	/* Calc approx time to dispatch */
+	jiffy_wait = ((tg->io_disp[rw] + 1) * HZ)/tg->iops[rw] + 1;
+
+	if (jiffy_wait > jiffy_elapsed)
+		jiffy_wait = jiffy_wait - jiffy_elapsed;
+	else
+		jiffy_wait = 1;
+
+	if (wait)
+		*wait = jiffy_wait;
+	return 0;
+}
+
+static bool tg_with_in_bps_limit(struct throtl_data *td, struct throtl_grp *tg,
+		struct bio *bio, unsigned long *wait)
+{
+	bool rw = bio_data_dir(bio);
+	u64 bytes_allowed, extra_bytes, tmp;
+	unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd;
+
+	jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw];
+
+	/* Slice has just started. Consider one slice interval */
+	if (!jiffy_elapsed)
+		jiffy_elapsed_rnd = throtl_slice;
+
+	jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, throtl_slice);
+
+	tmp = tg->bps[rw] * jiffy_elapsed_rnd;
+	do_div(tmp, HZ);
+	bytes_allowed = tmp;
+
+	if (tg->bytes_disp[rw] + bio->bi_size <= bytes_allowed) {
+		if (wait)
+			*wait = 0;
+		return 1;
+	}
+
+	/* Calc approx time to dispatch */
+	extra_bytes = tg->bytes_disp[rw] + bio->bi_size - bytes_allowed;
+	jiffy_wait = div64_u64(extra_bytes * HZ, tg->bps[rw]);
+
+	if (!jiffy_wait)
+		jiffy_wait = 1;
+
+	/*
+	 * This wait time is without taking into consideration the rounding
+	 * up we did. Add that time also.
+	 */
+	jiffy_wait = jiffy_wait + (jiffy_elapsed_rnd - jiffy_elapsed);
+	if (wait)
+		*wait = jiffy_wait;
+	return 0;
+}
+
+/*
+ * Returns whether one can dispatch a bio or not. Also returns approx number
+ * of jiffies to wait before this bio is with-in IO rate and can be dispatched
+ */
+static bool tg_may_dispatch(struct throtl_data *td, struct throtl_grp *tg,
+				struct bio *bio, unsigned long *wait)
+{
+	bool rw = bio_data_dir(bio);
+	unsigned long bps_wait = 0, iops_wait = 0, max_wait = 0;
+
+	/*
+ 	 * Currently whole state machine of group depends on first bio
+	 * queued in the group bio list. So one should not be calling
+	 * this function with a different bio if there are other bios
+	 * queued.
+	 */
+	BUG_ON(tg->nr_queued[rw] && bio != bio_list_peek(&tg->bio_lists[rw]));
+
+	/* If tg->bps = -1, then BW is unlimited */
+	if (tg->bps[rw] == -1 && tg->iops[rw] == -1) {
+		if (wait)
+			*wait = 0;
+		return 1;
+	}
+
+	/*
+	 * If previous slice expired, start a new one otherwise renew/extend
+	 * existing slice to make sure it is at least throtl_slice interval
+	 * long since now.
+	 */
+	if (throtl_slice_used(td, tg, rw))
+		throtl_start_new_slice(td, tg, rw);
+	else {
+		if (time_before(tg->slice_end[rw], jiffies + throtl_slice))
+			throtl_extend_slice(td, tg, rw, jiffies + throtl_slice);
+	}
+
+	if (tg_with_in_bps_limit(td, tg, bio, &bps_wait)
+	    && tg_with_in_iops_limit(td, tg, bio, &iops_wait)) {
+		if (wait)
+			*wait = 0;
+		return 1;
+	}
+
+	max_wait = max(bps_wait, iops_wait);
+
+	if (wait)
+		*wait = max_wait;
+
+	if (time_before(tg->slice_end[rw], jiffies + max_wait))
+		throtl_extend_slice(td, tg, rw, jiffies + max_wait);
+
+	return 0;
+}
+
+static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio)
+{
+	bool rw = bio_data_dir(bio);
+	bool sync = bio->bi_rw & REQ_SYNC;
+
+	/* Charge the bio to the group */
+	tg->bytes_disp[rw] += bio->bi_size;
+	tg->io_disp[rw]++;
+
+	/*
+	 * TODO: This will take blkg->stats_lock. Figure out a way
+	 * to avoid this cost.
+	 */
+	blkiocg_update_dispatch_stats(&tg->blkg, bio->bi_size, rw, sync);
+}
+
+static void throtl_add_bio_tg(struct throtl_data *td, struct throtl_grp *tg,
+			struct bio *bio)
+{
+	bool rw = bio_data_dir(bio);
+
+	bio_list_add(&tg->bio_lists[rw], bio);
+	/* Take a bio reference on tg */
+	throtl_ref_get_tg(tg);
+	tg->nr_queued[rw]++;
+	td->nr_queued[rw]++;
+	throtl_enqueue_tg(td, tg);
+}
+
+static void tg_update_disptime(struct throtl_data *td, struct throtl_grp *tg)
+{
+	unsigned long read_wait = -1, write_wait = -1, min_wait = -1, disptime;
+	struct bio *bio;
+
+	if ((bio = bio_list_peek(&tg->bio_lists[READ])))
+		tg_may_dispatch(td, tg, bio, &read_wait);
+
+	if ((bio = bio_list_peek(&tg->bio_lists[WRITE])))
+		tg_may_dispatch(td, tg, bio, &write_wait);
+
+	min_wait = min(read_wait, write_wait);
+	disptime = jiffies + min_wait;
+
+	/* Update dispatch time */
+	throtl_dequeue_tg(td, tg);
+	tg->disptime = disptime;
+	throtl_enqueue_tg(td, tg);
+}
+
+static void tg_dispatch_one_bio(struct throtl_data *td, struct throtl_grp *tg,
+				bool rw, struct bio_list *bl)
+{
+	struct bio *bio;
+
+	bio = bio_list_pop(&tg->bio_lists[rw]);
+	tg->nr_queued[rw]--;
+	/* Drop bio reference on tg */
+	throtl_put_tg(tg);
+
+	BUG_ON(td->nr_queued[rw] <= 0);
+	td->nr_queued[rw]--;
+
+	throtl_charge_bio(tg, bio);
+	bio_list_add(bl, bio);
+	bio->bi_rw |= REQ_THROTTLED;
+
+	throtl_trim_slice(td, tg, rw);
+}
+
+static int throtl_dispatch_tg(struct throtl_data *td, struct throtl_grp *tg,
+				struct bio_list *bl)
+{
+	unsigned int nr_reads = 0, nr_writes = 0;
+	unsigned int max_nr_reads = throtl_grp_quantum*3/4;
+	unsigned int max_nr_writes = throtl_grp_quantum - nr_reads;
+	struct bio *bio;
+
+	/* Try to dispatch 75% READS and 25% WRITES */
+
+	while ((bio = bio_list_peek(&tg->bio_lists[READ]))
+		&& tg_may_dispatch(td, tg, bio, NULL)) {
+
+		tg_dispatch_one_bio(td, tg, bio_data_dir(bio), bl);
+		nr_reads++;
+
+		if (nr_reads >= max_nr_reads)
+			break;
+	}
+
+	while ((bio = bio_list_peek(&tg->bio_lists[WRITE]))
+		&& tg_may_dispatch(td, tg, bio, NULL)) {
+
+		tg_dispatch_one_bio(td, tg, bio_data_dir(bio), bl);
+		nr_writes++;
+
+		if (nr_writes >= max_nr_writes)
+			break;
+	}
+
+	return nr_reads + nr_writes;
+}
+
+static int throtl_select_dispatch(struct throtl_data *td, struct bio_list *bl)
+{
+	unsigned int nr_disp = 0;
+	struct throtl_grp *tg;
+	struct throtl_rb_root *st = &td->tg_service_tree;
+
+	while (1) {
+		tg = throtl_rb_first(st);
+
+		if (!tg)
+			break;
+
+		if (time_before(jiffies, tg->disptime))
+			break;
+
+		throtl_dequeue_tg(td, tg);
+
+		nr_disp += throtl_dispatch_tg(td, tg, bl);
+
+		if (tg->nr_queued[0] || tg->nr_queued[1]) {
+			tg_update_disptime(td, tg);
+			throtl_enqueue_tg(td, tg);
+		}
+
+		if (nr_disp >= throtl_quantum)
+			break;
+	}
+
+	return nr_disp;
+}
+
+static void throtl_process_limit_change(struct throtl_data *td)
+{
+	struct throtl_grp *tg;
+	struct hlist_node *pos, *n;
+
+	/*
+	 * Make sure atomic_inc() effects from
+	 * throtl_update_blkio_group_read_bps(), group of functions are
+	 * visible.
+	 * Is this required or smp_mb__after_atomic_inc() was suffcient
+	 * after the atomic_inc().
+	 */
+	smp_rmb();
+	if (!atomic_read(&td->limits_changed))
+		return;
+
+	throtl_log(td, "limit changed =%d", atomic_read(&td->limits_changed));
+
+	hlist_for_each_entry_safe(tg, pos, n, &td->tg_list, tg_node) {
+		/*
+		 * Do I need an smp_rmb() here to make sure tg->limits_changed
+		 * update is visible. I am relying on smp_rmb() at the
+		 * beginning of function and not putting a new one here.
+		 */
+
+		if (throtl_tg_on_rr(tg) && tg->limits_changed) {
+			throtl_log_tg(td, tg, "limit change rbps=%llu wbps=%llu"
+				" riops=%u wiops=%u", tg->bps[READ],
+				tg->bps[WRITE], tg->iops[READ],
+				tg->iops[WRITE]);
+			tg_update_disptime(td, tg);
+			tg->limits_changed = false;
+		}
+	}
+
+	smp_mb__before_atomic_dec();
+	atomic_dec(&td->limits_changed);
+	smp_mb__after_atomic_dec();
+}
+
+/* Dispatch throttled bios. Should be called without queue lock held. */
+static int throtl_dispatch(struct request_queue *q)
+{
+	struct throtl_data *td = q->td;
+	unsigned int nr_disp = 0;
+	struct bio_list bio_list_on_stack;
+	struct bio *bio;
+
+	spin_lock_irq(q->queue_lock);
+
+	throtl_process_limit_change(td);
+
+	if (!total_nr_queued(td))
+		goto out;
+
+	bio_list_init(&bio_list_on_stack);
+
+	throtl_log(td, "dispatch nr_queued=%lu read=%u write=%u",
+			total_nr_queued(td), td->nr_queued[READ],
+			td->nr_queued[WRITE]);
+
+	nr_disp = throtl_select_dispatch(td, &bio_list_on_stack);
+
+	if (nr_disp)
+		throtl_log(td, "bios disp=%u", nr_disp);
+
+	throtl_schedule_next_dispatch(td);
+out:
+	spin_unlock_irq(q->queue_lock);
+
+	/*
+	 * If we dispatched some requests, unplug the queue to make sure
+	 * immediate dispatch
+	 */
+	if (nr_disp) {
+		while((bio = bio_list_pop(&bio_list_on_stack)))
+			generic_make_request(bio);
+		blk_unplug(q);
+	}
+	return nr_disp;
+}
+
+void blk_throtl_work(struct work_struct *work)
+{
+	struct throtl_data *td = container_of(work, struct throtl_data,
+					throtl_work.work);
+	struct request_queue *q = td->queue;
+
+	throtl_dispatch(q);
+}
+
+/* Call with queue lock held */
+void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay)
+{
+
+	struct throtl_data *td = q->td;
+	struct delayed_work *dwork = &td->throtl_work;
+
+	if (total_nr_queued(td) > 0) {
+		/*
+		 * We might have a work scheduled to be executed in future.
+		 * Cancel that and schedule a new one.
+		 */
+		__cancel_delayed_work(dwork);
+		kblockd_schedule_delayed_work(q, dwork, delay);
+		throtl_log(td, "schedule work. delay=%lu jiffies=%lu",
+				delay, jiffies);
+	}
+}
+EXPORT_SYMBOL(throtl_schedule_delayed_work);
+
+static void
+throtl_destroy_tg(struct throtl_data *td, struct throtl_grp *tg)
+{
+	/* Something wrong if we are trying to remove same group twice */
+	BUG_ON(hlist_unhashed(&tg->tg_node));
+
+	hlist_del_init(&tg->tg_node);
+
+	/*
+	 * Put the reference taken at the time of creation so that when all
+	 * queues are gone, group can be destroyed.
+	 */
+	throtl_put_tg(tg);
+	td->nr_undestroyed_grps--;
+}
+
+static void throtl_release_tgs(struct throtl_data *td)
+{
+	struct hlist_node *pos, *n;
+	struct throtl_grp *tg;
+
+	hlist_for_each_entry_safe(tg, pos, n, &td->tg_list, tg_node) {
+		/*
+		 * If cgroup removal path got to blk_group first and removed
+		 * it from cgroup list, then it will take care of destroying
+		 * cfqg also.
+		 */
+		if (!blkiocg_del_blkio_group(&tg->blkg))
+			throtl_destroy_tg(td, tg);
+	}
+}
+
+static void throtl_td_free(struct throtl_data *td)
+{
+	kfree(td);
+}
+
+/*
+ * Blk cgroup controller notification saying that blkio_group object is being
+ * delinked as associated cgroup object is going away. That also means that
+ * no new IO will come in this group. So get rid of this group as soon as
+ * any pending IO in the group is finished.
+ *
+ * This function is called under rcu_read_lock(). key is the rcu protected
+ * pointer. That means "key" is a valid throtl_data pointer as long as we are
+ * rcu read lock.
+ *
+ * "key" was fetched from blkio_group under blkio_cgroup->lock. That means
+ * it should not be NULL as even if queue was going away, cgroup deltion
+ * path got to it first.
+ */
+void throtl_unlink_blkio_group(void *key, struct blkio_group *blkg)
+{
+	unsigned long flags;
+	struct throtl_data *td = key;
+
+	spin_lock_irqsave(td->queue->queue_lock, flags);
+	throtl_destroy_tg(td, tg_of_blkg(blkg));
+	spin_unlock_irqrestore(td->queue->queue_lock, flags);
+}
+
+/*
+ * For all update functions, key should be a valid pointer because these
+ * update functions are called under blkcg_lock, that means, blkg is
+ * valid and in turn key is valid. queue exit path can not race becuase
+ * of blkcg_lock
+ *
+ * Can not take queue lock in update functions as queue lock under blkcg_lock
+ * is not allowed. Under other paths we take blkcg_lock under queue_lock.
+ */
+static void throtl_update_blkio_group_read_bps(void *key,
+				struct blkio_group *blkg, u64 read_bps)
+{
+	struct throtl_data *td = key;
+
+	tg_of_blkg(blkg)->bps[READ] = read_bps;
+	/* Make sure read_bps is updated before setting limits_changed */
+	smp_wmb();
+	tg_of_blkg(blkg)->limits_changed = true;
+
+	/* Make sure tg->limits_changed is updated before td->limits_changed */
+	smp_mb__before_atomic_inc();
+	atomic_inc(&td->limits_changed);
+	smp_mb__after_atomic_inc();
+
+	/* Schedule a work now to process the limit change */
+	throtl_schedule_delayed_work(td->queue, 0);
+}
+
+static void throtl_update_blkio_group_write_bps(void *key,
+				struct blkio_group *blkg, u64 write_bps)
+{
+	struct throtl_data *td = key;
+
+	tg_of_blkg(blkg)->bps[WRITE] = write_bps;
+	smp_wmb();
+	tg_of_blkg(blkg)->limits_changed = true;
+	smp_mb__before_atomic_inc();
+	atomic_inc(&td->limits_changed);
+	smp_mb__after_atomic_inc();
+	throtl_schedule_delayed_work(td->queue, 0);
+}
+
+static void throtl_update_blkio_group_read_iops(void *key,
+			struct blkio_group *blkg, unsigned int read_iops)
+{
+	struct throtl_data *td = key;
+
+	tg_of_blkg(blkg)->iops[READ] = read_iops;
+	smp_wmb();
+	tg_of_blkg(blkg)->limits_changed = true;
+	smp_mb__before_atomic_inc();
+	atomic_inc(&td->limits_changed);
+	smp_mb__after_atomic_inc();
+	throtl_schedule_delayed_work(td->queue, 0);
+}
+
+static void throtl_update_blkio_group_write_iops(void *key,
+			struct blkio_group *blkg, unsigned int write_iops)
+{
+	struct throtl_data *td = key;
+
+	tg_of_blkg(blkg)->iops[WRITE] = write_iops;
+	smp_wmb();
+	tg_of_blkg(blkg)->limits_changed = true;
+	smp_mb__before_atomic_inc();
+	atomic_inc(&td->limits_changed);
+	smp_mb__after_atomic_inc();
+	throtl_schedule_delayed_work(td->queue, 0);
+}
+
+void throtl_shutdown_timer_wq(struct request_queue *q)
+{
+	struct throtl_data *td = q->td;
+
+	cancel_delayed_work_sync(&td->throtl_work);
+}
+
+static struct blkio_policy_type blkio_policy_throtl = {
+	.ops = {
+		.blkio_unlink_group_fn = throtl_unlink_blkio_group,
+		.blkio_update_group_read_bps_fn =
+					throtl_update_blkio_group_read_bps,
+		.blkio_update_group_write_bps_fn =
+					throtl_update_blkio_group_write_bps,
+		.blkio_update_group_read_iops_fn =
+					throtl_update_blkio_group_read_iops,
+		.blkio_update_group_write_iops_fn =
+					throtl_update_blkio_group_write_iops,
+	},
+	.plid = BLKIO_POLICY_THROTL,
+};
+
+int blk_throtl_bio(struct request_queue *q, struct bio **biop)
+{
+	struct throtl_data *td = q->td;
+	struct throtl_grp *tg;
+	struct bio *bio = *biop;
+	bool rw = bio_data_dir(bio), update_disptime = true;
+
+	if (bio->bi_rw & REQ_THROTTLED) {
+		bio->bi_rw &= ~REQ_THROTTLED;
+		return 0;
+	}
+
+	spin_lock_irq(q->queue_lock);
+	tg = throtl_get_tg(td);
+
+	if (tg->nr_queued[rw]) {
+		/*
+		 * There is already another bio queued in same dir. No
+		 * need to update dispatch time.
+		 * Still update the disptime if rate limits on this group
+		 * were changed.
+		 */
+		if (!tg->limits_changed)
+			update_disptime = false;
+		else
+			tg->limits_changed = false;
+
+		goto queue_bio;
+	}
+
+	/* Bio is with-in rate limit of group */
+	if (tg_may_dispatch(td, tg, bio, NULL)) {
+		throtl_charge_bio(tg, bio);
+		goto out;
+	}
+
+queue_bio:
+	throtl_log_tg(td, tg, "[%c] bio. bdisp=%u sz=%u bps=%llu"
+			" iodisp=%u iops=%u queued=%d/%d",
+			rw == READ ? 'R' : 'W',
+			tg->bytes_disp[rw], bio->bi_size, tg->bps[rw],
+			tg->io_disp[rw], tg->iops[rw],
+			tg->nr_queued[READ], tg->nr_queued[WRITE]);
+
+	throtl_add_bio_tg(q->td, tg, bio);
+	*biop = NULL;
+
+	if (update_disptime) {
+		tg_update_disptime(td, tg);
+		throtl_schedule_next_dispatch(td);
+	}
+
+out:
+	spin_unlock_irq(q->queue_lock);
+	return 0;
+}
+
+int blk_throtl_init(struct request_queue *q)
+{
+	struct throtl_data *td;
+	struct throtl_grp *tg;
+
+	td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node);
+	if (!td)
+		return -ENOMEM;
+
+	INIT_HLIST_HEAD(&td->tg_list);
+	td->tg_service_tree = THROTL_RB_ROOT;
+	atomic_set(&td->limits_changed, 0);
+
+	/* Init root group */
+	tg = &td->root_tg;
+	INIT_HLIST_NODE(&tg->tg_node);
+	RB_CLEAR_NODE(&tg->rb_node);
+	bio_list_init(&tg->bio_lists[0]);
+	bio_list_init(&tg->bio_lists[1]);
+
+	/* Practically unlimited BW */
+	tg->bps[0] = tg->bps[1] = -1;
+	tg->iops[0] = tg->iops[1] = -1;
+
+	/*
+	 * Set root group reference to 2. One reference will be dropped when
+	 * all groups on tg_list are being deleted during queue exit. Other
+	 * reference will remain there as we don't want to delete this group
+	 * as it is statically allocated and gets destroyed when throtl_data
+	 * goes away.
+	 */
+	atomic_set(&tg->ref, 2);
+	hlist_add_head(&tg->tg_node, &td->tg_list);
+	td->nr_undestroyed_grps++;
+
+	INIT_DELAYED_WORK(&td->throtl_work, blk_throtl_work);
+
+	rcu_read_lock();
+	blkiocg_add_blkio_group(&blkio_root_cgroup, &tg->blkg, (void *)td,
+					0, BLKIO_POLICY_THROTL);
+	rcu_read_unlock();
+
+	/* Attach throtl data to request queue */
+	td->queue = q;
+	q->td = td;
+	return 0;
+}
+
+void blk_throtl_exit(struct request_queue *q)
+{
+	struct throtl_data *td = q->td;
+	bool wait = false;
+
+	BUG_ON(!td);
+
+	throtl_shutdown_timer_wq(q);
+
+	spin_lock_irq(q->queue_lock);
+	throtl_release_tgs(td);
+
+	/* If there are other groups */
+	if (td->nr_undestroyed_grps > 0)
+		wait = true;
+
+	spin_unlock_irq(q->queue_lock);
+
+	/*
+	 * Wait for tg->blkg->key accessors to exit their grace periods.
+	 * Do this wait only if there are other undestroyed groups out
+	 * there (other than root group). This can happen if cgroup deletion
+	 * path claimed the responsibility of cleaning up a group before
+	 * queue cleanup code get to the group.
+	 *
+	 * Do not call synchronize_rcu() unconditionally as there are drivers
+	 * which create/delete request queue hundreds of times during scan/boot
+	 * and synchronize_rcu() can take significant time and slow down boot.
+	 */
+	if (wait)
+		synchronize_rcu();
+
+	/*
+	 * Just being safe to make sure after previous flush if some body did
+	 * update limits through cgroup and another work got queued, cancel
+	 * it.
+	 */
+	throtl_shutdown_timer_wq(q);
+	throtl_td_free(td);
+}
+
+static int __init throtl_init(void)
+{
+	blkio_policy_register(&blkio_policy_throtl);
+	return 0;
+}
+
+module_init(throtl_init);

block/blk.h

@@ -110,10 +110,6 @@ void blk_queue_congestion_threshold(struct request_queue *q);
 
 int blk_dev_init(void);
 
-void elv_quiesce_start(struct request_queue *q);
-void elv_quiesce_end(struct request_queue *q);
-
-
 /*
  * Return the threshold (number of used requests) at which the queue is
  * considered to be congested.  It include a little hysteresis to keep the
@@ -132,14 +128,6 @@ static inline int queue_congestion_off_threshold(struct request_queue *q)
 	return q->nr_congestion_off;
 }
 
-#if defined(CONFIG_BLK_DEV_INTEGRITY)
-
-#define rq_for_each_integrity_segment(bvl, _rq, _iter)		\
-	__rq_for_each_bio(_iter.bio, _rq)			\
-		bip_for_each_vec(bvl, _iter.bio->bi_integrity, _iter.i)
-
-#endif /* BLK_DEV_INTEGRITY */
-
 static inline int blk_cpu_to_group(int cpu)
 {
 	int group = NR_CPUS;

block/cfq-iosched.c

@@ -160,6 +160,7 @@ enum wl_prio_t {
 	BE_WORKLOAD = 0,
 	RT_WORKLOAD = 1,
 	IDLE_WORKLOAD = 2,
+	CFQ_PRIO_NR,
 };
 
 /*
@@ -184,10 +185,19 @@ struct cfq_group {
 	/* number of cfqq currently on this group */
 	int nr_cfqq;
 
-	/* Per group busy queus average. Useful for workload slice calc. */
-	unsigned int busy_queues_avg[2];
 	/*
-	 * rr lists of queues with requests, onle rr for each priority class.
+	 * Per group busy queus average. Useful for workload slice calc. We
+	 * create the array for each prio class but at run time it is used
+	 * only for RT and BE class and slot for IDLE class remains unused.
+	 * This is primarily done to avoid confusion and a gcc warning.
+	 */
+	unsigned int busy_queues_avg[CFQ_PRIO_NR];
+	/*
+	 * rr lists of queues with requests. We maintain service trees for
+	 * RT and BE classes. These trees are subdivided in subclasses
+	 * of SYNC, SYNC_NOIDLE and ASYNC based on workload type. For IDLE
+	 * class there is no subclassification and all the cfq queues go on
+	 * a single tree service_tree_idle.
 	 * Counts are embedded in the cfq_rb_root
 	 */
 	struct cfq_rb_root service_trees[2][3];
@@ -221,7 +231,6 @@ struct cfq_data {
 	enum wl_type_t serving_type;
 	unsigned long workload_expires;
 	struct cfq_group *serving_group;
-	bool noidle_tree_requires_idle;
 
 	/*
 	 * Each priority tree is sorted by next_request position.  These
@@ -977,8 +986,8 @@ static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg)
 	return NULL;
 }
 
-void
-cfq_update_blkio_group_weight(struct blkio_group *blkg, unsigned int weight)
+void cfq_update_blkio_group_weight(void *key, struct blkio_group *blkg,
+					unsigned int weight)
 {
 	cfqg_of_blkg(blkg)->weight = weight;
 }
@@ -2180,7 +2189,6 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
 	slice = max_t(unsigned, slice, CFQ_MIN_TT);
 	cfq_log(cfqd, "workload slice:%d", slice);
 	cfqd->workload_expires = jiffies + slice;
-	cfqd->noidle_tree_requires_idle = false;
 }
 
 static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
@@ -3177,7 +3185,9 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	if (cfqq->queued[0] + cfqq->queued[1] >= 4)
 		cfq_mark_cfqq_deep(cfqq);
 
-	if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
+	if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE))
+		enable_idle = 0;
+	else if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
 	    (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
 		enable_idle = 0;
 	else if (sample_valid(cic->ttime_samples)) {
@@ -3494,17 +3504,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
 			cfq_slice_expired(cfqd, 1);
 		else if (sync && cfqq_empty &&
 			 !cfq_close_cooperator(cfqd, cfqq)) {
-			cfqd->noidle_tree_requires_idle |=
-				!(rq->cmd_flags & REQ_NOIDLE);
-			/*
-			 * Idling is enabled for SYNC_WORKLOAD.
-			 * SYNC_NOIDLE_WORKLOAD idles at the end of the tree
-			 * only if we processed at least one !REQ_NOIDLE request
-			 */
-			if (cfqd->serving_type == SYNC_WORKLOAD
-			    || cfqd->noidle_tree_requires_idle
-			    || cfqq->cfqg->nr_cfqq == 1)
-				cfq_arm_slice_timer(cfqd);
+			cfq_arm_slice_timer(cfqd);
 		}
 	}
 
@@ -4090,6 +4090,7 @@ static struct blkio_policy_type blkio_policy_cfq = {
 		.blkio_unlink_group_fn =	cfq_unlink_blkio_group,
 		.blkio_update_group_weight_fn =	cfq_update_blkio_group_weight,
 	},
+	.plid = BLKIO_POLICY_PROP,
 };
 #else
 static struct blkio_policy_type blkio_policy_cfq;

block/cfq.h

@@ -69,7 +69,7 @@ static inline void cfq_blkiocg_update_completion_stats(struct blkio_group *blkg,
 
 static inline void cfq_blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
 			struct blkio_group *blkg, void *key, dev_t dev) {
-	blkiocg_add_blkio_group(blkcg, blkg, key, dev);
+	blkiocg_add_blkio_group(blkcg, blkg, key, dev, BLKIO_POLICY_PROP);
 }
 
 static inline int cfq_blkiocg_del_blkio_group(struct blkio_group *blkg)

block/genhd.c

@@ -541,13 +541,15 @@ void add_disk(struct gendisk *disk)
 	disk->major = MAJOR(devt);
 	disk->first_minor = MINOR(devt);
 
+	/* Register BDI before referencing it from bdev */ 
+	bdi = &disk->queue->backing_dev_info;
+	bdi_register_dev(bdi, disk_devt(disk));
+
 	blk_register_region(disk_devt(disk), disk->minors, NULL,
 			    exact_match, exact_lock, disk);
 	register_disk(disk);
 	blk_register_queue(disk);
 
-	bdi = &disk->queue->backing_dev_info;
-	bdi_register_dev(bdi, disk_devt(disk));
 	retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
 				   "bdi");
 	WARN_ON(retval);
@@ -642,6 +644,7 @@ void __init printk_all_partitions(void)
 		struct hd_struct *part;
 		char name_buf[BDEVNAME_SIZE];
 		char devt_buf[BDEVT_SIZE];
+		u8 uuid[PARTITION_META_INFO_UUIDLTH * 2 + 1];
 
 		/*
 		 * Don't show empty devices or things that have been
@@ -660,10 +663,14 @@ void __init printk_all_partitions(void)
 		while ((part = disk_part_iter_next(&piter))) {
 			bool is_part0 = part == &disk->part0;
 
-			printk("%s%s %10llu %s", is_part0 ? "" : "  ",
+			uuid[0] = 0;
+			if (part->info)
+				part_unpack_uuid(part->info->uuid, uuid);
+
+			printk("%s%s %10llu %s %s", is_part0 ? "" : "  ",
 			       bdevt_str(part_devt(part), devt_buf),
 			       (unsigned long long)part->nr_sects >> 1,
-			       disk_name(disk, part->partno, name_buf));
+			       disk_name(disk, part->partno, name_buf), uuid);
 			if (is_part0) {
 				if (disk->driverfs_dev != NULL &&
 				    disk->driverfs_dev->driver != NULL)
@@ -925,8 +932,15 @@ static void disk_free_ptbl_rcu_cb(struct rcu_head *head)
 {
 	struct disk_part_tbl *ptbl =
 		container_of(head, struct disk_part_tbl, rcu_head);
+	struct gendisk *disk = ptbl->disk;
+	struct request_queue *q = disk->queue;
+	unsigned long flags;
 
 	kfree(ptbl);
+
+	spin_lock_irqsave(q->queue_lock, flags);
+	elv_quiesce_end(q);
+	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
 /**
@@ -944,11 +958,17 @@ static void disk_replace_part_tbl(struct gendisk *disk,
 				  struct disk_part_tbl *new_ptbl)
 {
 	struct disk_part_tbl *old_ptbl = disk->part_tbl;
+	struct request_queue *q = disk->queue;
 
 	rcu_assign_pointer(disk->part_tbl, new_ptbl);
 
 	if (old_ptbl) {
 		rcu_assign_pointer(old_ptbl->last_lookup, NULL);
+
+		spin_lock_irq(q->queue_lock);
+		elv_quiesce_start(q);
+		spin_unlock_irq(q->queue_lock);
+
 		call_rcu(&old_ptbl->rcu_head, disk_free_ptbl_rcu_cb);
 	}
 }
@@ -989,6 +1009,7 @@ int disk_expand_part_tbl(struct gendisk *disk, int partno)
 		return -ENOMEM;
 
 	new_ptbl->len = target;
+	new_ptbl->disk = disk;
 
 	for (i = 0; i < len; i++)
 		rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);
@@ -1004,6 +1025,7 @@ static void disk_release(struct device *dev)
 	kfree(disk->random);
 	disk_replace_part_tbl(disk, NULL);
 	free_part_stats(&disk->part0);
+	free_part_info(&disk->part0);
 	kfree(disk);
 }
 struct class block_class = {

block/ioctl.c

@@ -62,7 +62,7 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
 
 			/* all seems OK */
 			part = add_partition(disk, partno, start, length,
-					     ADDPART_FLAG_NONE);
+					     ADDPART_FLAG_NONE, NULL);
 			mutex_unlock(&bdev->bd_mutex);
 			return IS_ERR(part) ? PTR_ERR(part) : 0;
 		case BLKPG_DEL_PARTITION:

drivers/block/drbd/drbd_receiver.c

@@ -2972,7 +2972,6 @@ static int receive_sizes(struct drbd_conf *mdev, struct p_header *h)
 	 * we still need to figure out whether we accept that. */
 	mdev->p_size = p_size;
 
-#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
 	if (get_ldev(mdev)) {
 		warn_if_differ_considerably(mdev, "lower level device sizes",
 			   p_size, drbd_get_max_capacity(mdev->ldev));

drivers/md/dm-snap.c

@@ -706,8 +706,6 @@ static int dm_add_exception(void *context, chunk_t old, chunk_t new)
 	return 0;
 }
 
-#define min_not_zero(l, r) (((l) == 0) ? (r) : (((r) == 0) ? (l) : min(l, r)))
-
 /*
  * Return a minimum chunk size of all snapshots that have the specified origin.
  * Return zero if the origin has no snapshots.

drivers/md/dm-table.c

@@ -486,11 +486,6 @@ static int __table_get_device(struct dm_table *t, struct dm_target *ti,
 	return 0;
 }
 
-/*
- * Returns the minimum that is _not_ zero, unless both are zero.
- */
-#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
-
 int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
 			 sector_t start, sector_t len, void *data)
 {

drivers/s390/scsi/zfcp_scsi.c

@@ -681,6 +681,7 @@ void zfcp_scsi_set_prot(struct zfcp_adapter *adapter)
 	    adapter->adapter_features & FSF_FEATURE_DIX_PROT_TCPIP) {
 		mask |= SHOST_DIX_TYPE1_PROTECTION;
 		scsi_host_set_guard(shost, SHOST_DIX_GUARD_IP);
+		shost->sg_prot_tablesize = ZFCP_QDIO_MAX_SBALES_PER_REQ / 2;
 		shost->sg_tablesize = ZFCP_QDIO_MAX_SBALES_PER_REQ / 2;
 		shost->max_sectors = ZFCP_QDIO_MAX_SBALES_PER_REQ * 8 / 2;
 	}

drivers/scsi/hosts.c

@@ -376,6 +376,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 	shost->this_id = sht->this_id;
 	shost->can_queue = sht->can_queue;
 	shost->sg_tablesize = sht->sg_tablesize;
+	shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 	shost->cmd_per_lun = sht->cmd_per_lun;
 	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 	shost->use_clustering = sht->use_clustering;

drivers/scsi/scsi_lib.c

@@ -968,11 +968,13 @@ static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
  */
 int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 {
-	int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask);
+	struct request *rq = cmd->request;
+
+	int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask);
 	if (error)
 		goto err_exit;
 
-	if (blk_bidi_rq(cmd->request)) {
+	if (blk_bidi_rq(rq)) {
 		struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
 			scsi_sdb_cache, GFP_ATOMIC);
 		if (!bidi_sdb) {
@@ -980,28 +982,28 @@ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 			goto err_exit;
 		}
 
-		cmd->request->next_rq->special = bidi_sdb;
-		error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb,
-								    GFP_ATOMIC);
+		rq->next_rq->special = bidi_sdb;
+		error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC);
 		if (error)
 			goto err_exit;
 	}
 
-	if (blk_integrity_rq(cmd->request)) {
+	if (blk_integrity_rq(rq)) {
 		struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
 		int ivecs, count;
 
 		BUG_ON(prot_sdb == NULL);
-		ivecs = blk_rq_count_integrity_sg(cmd->request);
+		ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
 
 		if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
 			error = BLKPREP_DEFER;
 			goto err_exit;
 		}
 
-		count = blk_rq_map_integrity_sg(cmd->request,
+		count = blk_rq_map_integrity_sg(rq->q, rq->bio,
 						prot_sdb->table.sgl);
 		BUG_ON(unlikely(count > ivecs));
+		BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
 
 		cmd->prot_sdb = prot_sdb;
 		cmd->prot_sdb->table.nents = count;
@@ -1625,6 +1627,14 @@ struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
 	blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
 					SCSI_MAX_SG_CHAIN_SEGMENTS));
 
+	if (scsi_host_prot_dma(shost)) {
+		shost->sg_prot_tablesize =
+			min_not_zero(shost->sg_prot_tablesize,
+				     (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
+		BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
+		blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
+	}
+
 	blk_queue_max_hw_sectors(q, shost->max_sectors);
 	blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
 	blk_queue_segment_boundary(q, shost->dma_boundary);

drivers/scsi/scsi_sysfs.c

@@ -251,6 +251,7 @@ shost_rd_attr(host_busy, "%hu\n");
 shost_rd_attr(cmd_per_lun, "%hd\n");
 shost_rd_attr(can_queue, "%hd\n");
 shost_rd_attr(sg_tablesize, "%hu\n");
+shost_rd_attr(sg_prot_tablesize, "%hu\n");
 shost_rd_attr(unchecked_isa_dma, "%d\n");
 shost_rd_attr(prot_capabilities, "%u\n");
 shost_rd_attr(prot_guard_type, "%hd\n");
@@ -262,6 +263,7 @@ static struct attribute *scsi_sysfs_shost_attrs[] = {
 	&dev_attr_cmd_per_lun.attr,
 	&dev_attr_can_queue.attr,
 	&dev_attr_sg_tablesize.attr,
+	&dev_attr_sg_prot_tablesize.attr,
 	&dev_attr_unchecked_isa_dma.attr,
 	&dev_attr_proc_name.attr,
 	&dev_attr_scan.attr,

drivers/scsi/sd_dif.c

@@ -375,21 +375,20 @@ int sd_dif_prepare(struct request *rq, sector_t hw_sector, unsigned int sector_s
 	unsigned int i, j;
 	u32 phys, virt;
 
-	/* Already remapped? */
-	if (rq->cmd_flags & REQ_INTEGRITY)
-		return 0;
-
 	sdkp = rq->bio->bi_bdev->bd_disk->private_data;
 
 	if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
 		return 0;
 
-	rq->cmd_flags |= REQ_INTEGRITY;
 	phys = hw_sector & 0xffffffff;
 
 	__rq_for_each_bio(bio, rq) {
 		struct bio_vec *iv;
 
+		/* Already remapped? */
+		if (bio_flagged(bio, BIO_MAPPED_INTEGRITY))
+			break;
+
 		virt = bio->bi_integrity->bip_sector & 0xffffffff;
 
 		bip_for_each_vec(iv, bio->bi_integrity, i) {
@@ -408,6 +407,8 @@ int sd_dif_prepare(struct request *rq, sector_t hw_sector, unsigned int sector_s
 
 			kunmap_atomic(sdt, KM_USER0);
 		}
+
+		bio->bi_flags |= BIO_MAPPED_INTEGRITY;
 	}
 
 	return 0;

drivers/scsi/sg.c

@@ -1660,7 +1660,7 @@ static int sg_start_req(Sg_request *srp, unsigned char *cmd)
 	if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
 	    dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
 	    !sfp->parentdp->device->host->unchecked_isa_dma &&
-	    blk_rq_aligned(q, hp->dxferp, dxfer_len))
+	    blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
 		md = NULL;
 	else
 		md = &map_data;

fs/jbd/commit.c

@@ -318,7 +318,7 @@ void journal_commit_transaction(journal_t *journal)
 	int first_tag = 0;
 	int tag_flag;
 	int i;
-	int write_op = WRITE;
+	int write_op = WRITE_SYNC;
 
 	/*
 	 * First job: lock down the current transaction and wait for

fs/jbd2/commit.c

@@ -360,7 +360,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	int tag_bytes = journal_tag_bytes(journal);
 	struct buffer_head *cbh = NULL; /* For transactional checksums */
 	__u32 crc32_sum = ~0;
-	int write_op = WRITE;
+	int write_op = WRITE_SYNC;
 
 	/*
 	 * First job: lock down the current transaction and wait for

fs/partitions/check.c

@@ -352,6 +352,7 @@ static void part_release(struct device *dev)
 {
 	struct hd_struct *p = dev_to_part(dev);
 	free_part_stats(p);
+	free_part_info(p);
 	kfree(p);
 }
 
@@ -364,17 +365,25 @@ struct device_type part_type = {
 static void delete_partition_rcu_cb(struct rcu_head *head)
 {
 	struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
+	struct gendisk *disk = part_to_disk(part);
+	struct request_queue *q = disk->queue;
+	unsigned long flags;
 
 	part->start_sect = 0;
 	part->nr_sects = 0;
 	part_stat_set_all(part, 0);
 	put_device(part_to_dev(part));
+
+	spin_lock_irqsave(q->queue_lock, flags);
+	elv_quiesce_end(q);
+	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
 void delete_partition(struct gendisk *disk, int partno)
 {
 	struct disk_part_tbl *ptbl = disk->part_tbl;
 	struct hd_struct *part;
+	struct request_queue *q = disk->queue;
 
 	if (partno >= ptbl->len)
 		return;
@@ -389,6 +398,10 @@ void delete_partition(struct gendisk *disk, int partno)
 	kobject_put(part->holder_dir);
 	device_del(part_to_dev(part));
 
+	spin_lock_irq(q->queue_lock);
+	elv_quiesce_start(q);
+	spin_unlock_irq(q->queue_lock);
+
 	call_rcu(&part->rcu_head, delete_partition_rcu_cb);
 }
 
@@ -401,7 +414,8 @@ static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
 		   whole_disk_show, NULL);
 
 struct hd_struct *add_partition(struct gendisk *disk, int partno,
-				sector_t start, sector_t len, int flags)
+				sector_t start, sector_t len, int flags,
+				struct partition_meta_info *info)
 {
 	struct hd_struct *p;
 	dev_t devt = MKDEV(0, 0);
@@ -438,6 +452,14 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	p->partno = partno;
 	p->policy = get_disk_ro(disk);
 
+	if (info) {
+		struct partition_meta_info *pinfo = alloc_part_info(disk);
+		if (!pinfo)
+			goto out_free_stats;
+		memcpy(pinfo, info, sizeof(*info));
+		p->info = pinfo;
+	}
+
 	dname = dev_name(ddev);
 	if (isdigit(dname[strlen(dname) - 1]))
 		dev_set_name(pdev, "%sp%d", dname, partno);
@@ -451,7 +473,7 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
 
 	err = blk_alloc_devt(p, &devt);
 	if (err)
-		goto out_free_stats;
+		goto out_free_info;
 	pdev->devt = devt;
 
 	/* delay uevent until 'holders' subdir is created */
@@ -481,6 +503,8 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
 
 	return p;
 
+out_free_info:
+	free_part_info(p);
 out_free_stats:
 	free_part_stats(p);
 out_free:
@@ -642,6 +666,7 @@ rescan:
 	/* add partitions */
 	for (p = 1; p < state->limit; p++) {
 		sector_t size, from;
+		struct partition_meta_info *info = NULL;
 
 		size = state->parts[p].size;
 		if (!size)
@@ -675,8 +700,12 @@ rescan:
 				size = get_capacity(disk) - from;
 			}
 		}
+
+		if (state->parts[p].has_info)
+			info = &state->parts[p].info;
 		part = add_partition(disk, p, from, size,
-				     state->parts[p].flags);
+				     state->parts[p].flags,
+				     &state->parts[p].info);
 		if (IS_ERR(part)) {
 			printk(KERN_ERR " %s: p%d could not be added: %ld\n",
 			       disk->disk_name, p, -PTR_ERR(part));

fs/partitions/check.h

@@ -1,5 +1,6 @@
 #include <linux/pagemap.h>
 #include <linux/blkdev.h>
+#include <linux/genhd.h>
 
 /*
  * add_gd_partition adds a partitions details to the devices partition
@@ -12,6 +13,8 @@ struct parsed_partitions {
 		sector_t from;
 		sector_t size;
 		int flags;
+		bool has_info;
+		struct partition_meta_info info;
 	} parts[DISK_MAX_PARTS];
 	int next;
 	int limit;

fs/partitions/efi.c

@@ -94,6 +94,7 @@
  *
  ************************************************************/
 #include <linux/crc32.h>
+#include <linux/ctype.h>
 #include <linux/math64.h>
 #include <linux/slab.h>
 #include "check.h"
@@ -604,6 +605,7 @@ int efi_partition(struct parsed_partitions *state)
 	gpt_entry *ptes = NULL;
 	u32 i;
 	unsigned ssz = bdev_logical_block_size(state->bdev) / 512;
+	u8 unparsed_guid[37];
 
 	if (!find_valid_gpt(state, &gpt, &ptes) || !gpt || !ptes) {
 		kfree(gpt);
@@ -614,6 +616,9 @@ int efi_partition(struct parsed_partitions *state)
 	pr_debug("GUID Partition Table is valid!  Yea!\n");
 
 	for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
+		struct partition_meta_info *info;
+		unsigned label_count = 0;
+		unsigned label_max;
 		u64 start = le64_to_cpu(ptes[i].starting_lba);
 		u64 size = le64_to_cpu(ptes[i].ending_lba) -
 			   le64_to_cpu(ptes[i].starting_lba) + 1ULL;
@@ -627,6 +632,26 @@ int efi_partition(struct parsed_partitions *state)
 		if (!efi_guidcmp(ptes[i].partition_type_guid,
 				 PARTITION_LINUX_RAID_GUID))
 			state->parts[i + 1].flags = ADDPART_FLAG_RAID;
+
+		info = &state->parts[i + 1].info;
+		/* Instead of doing a manual swap to big endian, reuse the
+		 * common ASCII hex format as the interim.
+		 */
+		efi_guid_unparse(&ptes[i].unique_partition_guid, unparsed_guid);
+		part_pack_uuid(unparsed_guid, info->uuid);
+
+		/* Naively convert UTF16-LE to 7 bits. */
+		label_max = min(sizeof(info->volname) - 1,
+				sizeof(ptes[i].partition_name));
+		info->volname[label_max] = 0;
+		while (label_count < label_max) {
+			u8 c = ptes[i].partition_name[label_count] & 0xff;
+			if (c && !isprint(c))
+				c = '!';
+			info->volname[label_count] = c;
+			label_count++;
+		}
+		state->parts[i + 1].has_info = true;
 	}
 	kfree(ptes);
 	kfree(gpt);

include/linux/bio.h

@@ -346,8 +346,15 @@ static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 }
 
 #else
-#define bvec_kmap_irq(bvec, flags)	(page_address((bvec)->bv_page) + (bvec)->bv_offset)
-#define bvec_kunmap_irq(buf, flags)	do { *(flags) = 0; } while (0)
+static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
+{
+	return page_address(bvec->bv_page) + bvec->bv_offset;
+}
+
+static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
+{
+	*flags = 0;
+}
 #endif
 
 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
@@ -496,6 +503,10 @@ static inline struct bio *bio_list_get(struct bio_list *bl)
 #define bip_for_each_vec(bvl, bip, i)					\
 	__bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
 
+#define bio_for_each_integrity_vec(_bvl, _bio, _iter)			\
+	for_each_bio(_bio)						\
+		bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
+
 #define bio_integrity(bio) (bio->bi_integrity != NULL)
 
 extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);

include/linux/blk_types.h

@@ -97,6 +97,7 @@ struct bio {
 #define BIO_NULL_MAPPED 9	/* contains invalid user pages */
 #define BIO_FS_INTEGRITY 10	/* fs owns integrity data, not block layer */
 #define BIO_QUIET	11	/* Make BIO Quiet */
+#define BIO_MAPPED_INTEGRITY 12/* integrity metadata has been remapped */
 #define bio_flagged(bio, flag)	((bio)->bi_flags & (1 << (flag)))
 
 /*
@@ -130,6 +131,8 @@ enum rq_flag_bits {
 	/* bio only flags */
 	__REQ_UNPLUG,		/* unplug the immediately after submission */
 	__REQ_RAHEAD,		/* read ahead, can fail anytime */
+	__REQ_THROTTLED,	/* This bio has already been subjected to
+				 * throttling rules. Don't do it again. */
 
 	/* request only flags */
 	__REQ_SORTED,		/* elevator knows about this request */
@@ -146,7 +149,6 @@ enum rq_flag_bits {
 	__REQ_ORDERED_COLOR,	/* is before or after barrier */
 	__REQ_ALLOCED,		/* request came from our alloc pool */
 	__REQ_COPY_USER,	/* contains copies of user pages */
-	__REQ_INTEGRITY,	/* integrity metadata has been remapped */
 	__REQ_FLUSH,		/* request for cache flush */
 	__REQ_IO_STAT,		/* account I/O stat */
 	__REQ_MIXED_MERGE,	/* merge of different types, fail separately */
@@ -172,6 +174,7 @@ enum rq_flag_bits {
 
 #define REQ_UNPLUG		(1 << __REQ_UNPLUG)
 #define REQ_RAHEAD		(1 << __REQ_RAHEAD)
+#define REQ_THROTTLED		(1 << __REQ_THROTTLED)
 
 #define REQ_SORTED		(1 << __REQ_SORTED)
 #define REQ_SOFTBARRIER		(1 << __REQ_SOFTBARRIER)
@@ -187,7 +190,6 @@ enum rq_flag_bits {
 #define REQ_ORDERED_COLOR	(1 << __REQ_ORDERED_COLOR)
 #define REQ_ALLOCED		(1 << __REQ_ALLOCED)
 #define REQ_COPY_USER		(1 << __REQ_COPY_USER)
-#define REQ_INTEGRITY		(1 << __REQ_INTEGRITY)
 #define REQ_FLUSH		(1 << __REQ_FLUSH)
 #define REQ_IO_STAT		(1 << __REQ_IO_STAT)
 #define REQ_MIXED_MERGE		(1 << __REQ_MIXED_MERGE)

include/linux/blkdev.h

@@ -115,6 +115,7 @@ struct request {
 	void *elevator_private3;
 
 	struct gendisk *rq_disk;
+	struct hd_struct *part;
 	unsigned long start_time;
 #ifdef CONFIG_BLK_CGROUP
 	unsigned long long start_time_ns;
@@ -124,6 +125,9 @@ struct request {
 	 * physical address coalescing is performed.
 	 */
 	unsigned short nr_phys_segments;
+#if defined(CONFIG_BLK_DEV_INTEGRITY)
+	unsigned short nr_integrity_segments;
+#endif
 
 	unsigned short ioprio;
 
@@ -243,6 +247,7 @@ struct queue_limits {
 
 	unsigned short		logical_block_size;
 	unsigned short		max_segments;
+	unsigned short		max_integrity_segments;
 
 	unsigned char		misaligned;
 	unsigned char		discard_misaligned;
@@ -367,6 +372,11 @@ struct request_queue
 #if defined(CONFIG_BLK_DEV_BSG)
 	struct bsg_class_device bsg_dev;
 #endif
+
+#ifdef CONFIG_BLK_DEV_THROTTLING
+	/* Throttle data */
+	struct throtl_data *td;
+#endif
 };
 
 #define QUEUE_FLAG_CLUSTER	0	/* cluster several segments into 1 */
@@ -851,7 +861,7 @@ extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 extern void blk_queue_max_discard_sectors(struct request_queue *q,
 		unsigned int max_discard_sectors);
 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
-extern void blk_queue_physical_block_size(struct request_queue *, unsigned short);
+extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
 extern void blk_queue_alignment_offset(struct request_queue *q,
 				       unsigned int alignment);
 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
@@ -1004,7 +1014,7 @@ static inline unsigned int queue_physical_block_size(struct request_queue *q)
 	return q->limits.physical_block_size;
 }
 
-static inline int bdev_physical_block_size(struct block_device *bdev)
+static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
 {
 	return queue_physical_block_size(bdev_get_queue(bdev));
 }
@@ -1093,11 +1103,11 @@ static inline int queue_dma_alignment(struct request_queue *q)
 	return q ? q->dma_alignment : 511;
 }
 
-static inline int blk_rq_aligned(struct request_queue *q, void *addr,
+static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
 				 unsigned int len)
 {
 	unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
-	return !((unsigned long)addr & alignment) && !(len & alignment);
+	return !(addr & alignment) && !(len & alignment);
 }
 
 /* assumes size > 256 */
@@ -1127,6 +1137,7 @@ static inline void put_dev_sector(Sector p)
 
 struct work_struct;
 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
+int kblockd_schedule_delayed_work(struct request_queue *q, struct delayed_work *dwork, unsigned long delay);
 
 #ifdef CONFIG_BLK_CGROUP
 /*
@@ -1170,6 +1181,24 @@ static inline uint64_t rq_io_start_time_ns(struct request *req)
 }
 #endif
 
+#ifdef CONFIG_BLK_DEV_THROTTLING
+extern int blk_throtl_init(struct request_queue *q);
+extern void blk_throtl_exit(struct request_queue *q);
+extern int blk_throtl_bio(struct request_queue *q, struct bio **bio);
+extern void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay);
+extern void throtl_shutdown_timer_wq(struct request_queue *q);
+#else /* CONFIG_BLK_DEV_THROTTLING */
+static inline int blk_throtl_bio(struct request_queue *q, struct bio **bio)
+{
+	return 0;
+}
+
+static inline int blk_throtl_init(struct request_queue *q) { return 0; }
+static inline int blk_throtl_exit(struct request_queue *q) { return 0; }
+static inline void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay) {}
+static inline void throtl_shutdown_timer_wq(struct request_queue *q) {}
+#endif /* CONFIG_BLK_DEV_THROTTLING */
+
 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
 	MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
@@ -1213,8 +1242,13 @@ struct blk_integrity {
 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
 extern void blk_integrity_unregister(struct gendisk *);
 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
-extern int blk_rq_map_integrity_sg(struct request *, struct scatterlist *);
-extern int blk_rq_count_integrity_sg(struct request *);
+extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
+				   struct scatterlist *);
+extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
+extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
+				  struct request *);
+extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
+				   struct bio *);
 
 static inline
 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
@@ -1235,16 +1269,32 @@ static inline int blk_integrity_rq(struct request *rq)
 	return bio_integrity(rq->bio);
 }
 
+static inline void blk_queue_max_integrity_segments(struct request_queue *q,
+						    unsigned int segs)
+{
+	q->limits.max_integrity_segments = segs;
+}
+
+static inline unsigned short
+queue_max_integrity_segments(struct request_queue *q)
+{
+	return q->limits.max_integrity_segments;
+}
+
 #else /* CONFIG_BLK_DEV_INTEGRITY */
 
 #define blk_integrity_rq(rq)			(0)
-#define blk_rq_count_integrity_sg(a)		(0)
-#define blk_rq_map_integrity_sg(a, b)		(0)
+#define blk_rq_count_integrity_sg(a, b)		(0)
+#define blk_rq_map_integrity_sg(a, b, c)	(0)
 #define bdev_get_integrity(a)			(0)
 #define blk_get_integrity(a)			(0)
 #define blk_integrity_compare(a, b)		(0)
 #define blk_integrity_register(a, b)		(0)
 #define blk_integrity_unregister(a)		do { } while (0);
+#define blk_queue_max_integrity_segments(a, b)	do { } while (0);
+#define queue_max_integrity_segments(a)		(0)
+#define blk_integrity_merge_rq(a, b, c)		(0)
+#define blk_integrity_merge_bio(a, b, c)	(0)
 
 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 

include/linux/elevator.h

@@ -122,6 +122,8 @@ extern void elv_completed_request(struct request_queue *, struct request *);
 extern int elv_set_request(struct request_queue *, struct request *, gfp_t);
 extern void elv_put_request(struct request_queue *, struct request *);
 extern void elv_drain_elevator(struct request_queue *);
+extern void elv_quiesce_start(struct request_queue *);
+extern void elv_quiesce_end(struct request_queue *);
 
 /*
  * io scheduler registration

include/linux/genhd.h

@@ -12,6 +12,7 @@
 #include <linux/types.h>
 #include <linux/kdev_t.h>
 #include <linux/rcupdate.h>
+#include <linux/slab.h>
 
 #ifdef CONFIG_BLOCK
 
@@ -86,7 +87,15 @@ struct disk_stats {
 	unsigned long io_ticks;
 	unsigned long time_in_queue;
 };
-	
+
+#define PARTITION_META_INFO_VOLNAMELTH	64
+#define PARTITION_META_INFO_UUIDLTH	16
+
+struct partition_meta_info {
+	u8 uuid[PARTITION_META_INFO_UUIDLTH];	/* always big endian */
+	u8 volname[PARTITION_META_INFO_VOLNAMELTH];
+};
+
 struct hd_struct {
 	sector_t start_sect;
 	sector_t nr_sects;
@@ -95,6 +104,7 @@ struct hd_struct {
 	struct device __dev;
 	struct kobject *holder_dir;
 	int policy, partno;
+	struct partition_meta_info *info;
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 	int make_it_fail;
 #endif
@@ -130,6 +140,7 @@ struct disk_part_tbl {
 	struct rcu_head rcu_head;
 	int len;
 	struct hd_struct __rcu *last_lookup;
+	struct gendisk *disk;
 	struct hd_struct __rcu *part[];
 };
 
@@ -181,6 +192,30 @@ static inline struct gendisk *part_to_disk(struct hd_struct *part)
 	return NULL;
 }
 
+static inline void part_pack_uuid(const u8 *uuid_str, u8 *to)
+{
+	int i;
+	for (i = 0; i < 16; ++i) {
+		*to++ = (hex_to_bin(*uuid_str) << 4) |
+			(hex_to_bin(*(uuid_str + 1)));
+		uuid_str += 2;
+		switch (i) {
+		case 3:
+		case 5:
+		case 7:
+		case 9:
+			uuid_str++;
+			continue;
+		}
+	}
+}
+
+static inline char *part_unpack_uuid(const u8 *uuid, char *out)
+{
+	sprintf(out, "%pU", uuid);
+	return out;
+}
+
 static inline int disk_max_parts(struct gendisk *disk)
 {
 	if (disk->flags & GENHD_FL_EXT_DEVT)
@@ -342,6 +377,19 @@ static inline int part_in_flight(struct hd_struct *part)
 	return part->in_flight[0] + part->in_flight[1];
 }
 
+static inline struct partition_meta_info *alloc_part_info(struct gendisk *disk)
+{
+	if (disk)
+		return kzalloc_node(sizeof(struct partition_meta_info),
+				    GFP_KERNEL, disk->node_id);
+	return kzalloc(sizeof(struct partition_meta_info), GFP_KERNEL);
+}
+
+static inline void free_part_info(struct hd_struct *part)
+{
+	kfree(part->info);
+}
+
 /* block/blk-core.c */
 extern void part_round_stats(int cpu, struct hd_struct *part);
 
@@ -533,7 +581,9 @@ extern int disk_expand_part_tbl(struct gendisk *disk, int target);
 extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
 extern struct hd_struct * __must_check add_partition(struct gendisk *disk,
 						     int partno, sector_t start,
-						     sector_t len, int flags);
+						     sector_t len, int flags,
+						     struct partition_meta_info
+						       *info);
 extern void delete_partition(struct gendisk *, int);
 extern void printk_all_partitions(void);
 

include/linux/kernel.h

@@ -651,6 +651,16 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 	(void) (&_max1 == &_max2);		\
 	_max1 > _max2 ? _max1 : _max2; })
 
+/**
+ * min_not_zero - return the minimum that is _not_ zero, unless both are zero
+ * @x: value1
+ * @y: value2
+ */
+#define min_not_zero(x, y) ({			\
+	typeof(x) __x = (x);			\
+	typeof(y) __y = (y);			\
+	__x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
+
 /**
  * clamp - return a value clamped to a given range with strict typechecking
  * @val: current value

include/linux/sched.h

@@ -336,6 +336,9 @@ extern unsigned long sysctl_hung_task_warnings;
 extern int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
 					 void __user *buffer,
 					 size_t *lenp, loff_t *ppos);
+#else
+/* Avoid need for ifdefs elsewhere in the code */
+enum { sysctl_hung_task_timeout_secs = 0 };
 #endif
 
 /* Attach to any functions which should be ignored in wchan output. */

include/scsi/scsi.h

@@ -31,6 +31,12 @@ struct scsi_cmnd;
 #define SCSI_MAX_SG_CHAIN_SEGMENTS	SCSI_MAX_SG_SEGMENTS
 #endif
 
+/*
+ * DIX-capable adapters effectively support infinite chaining for the
+ * protection information scatterlist
+ */
+#define SCSI_MAX_PROT_SG_SEGMENTS	0xFFFF
+
 /*
  * Special value for scanning to specify scanning or rescanning of all
  * possible channels, (target) ids, or luns on a given shost.

include/scsi/scsi_host.h

@@ -388,6 +388,7 @@ struct scsi_host_template {
 	 * of scatter-gather.
 	 */
 	unsigned short sg_tablesize;
+	unsigned short sg_prot_tablesize;
 
 	/*
 	 * Set this if the host adapter has limitations beside segment count.
@@ -599,6 +600,7 @@ struct Scsi_Host {
 	int can_queue;
 	short cmd_per_lun;
 	short unsigned int sg_tablesize;
+	short unsigned int sg_prot_tablesize;
 	short unsigned int max_sectors;
 	unsigned long dma_boundary;
 	/* 
@@ -823,6 +825,11 @@ static inline unsigned int scsi_host_get_prot(struct Scsi_Host *shost)
 	return shost->prot_capabilities;
 }
 
+static inline int scsi_host_prot_dma(struct Scsi_Host *shost)
+{
+	return shost->prot_capabilities >= SHOST_DIX_TYPE0_PROTECTION;
+}
+
 static inline unsigned int scsi_host_dif_capable(struct Scsi_Host *shost, unsigned int target_type)
 {
 	static unsigned char cap[] = { 0,

init/Kconfig

@@ -661,11 +661,14 @@ config BLK_CGROUP
 
 	Currently, CFQ IO scheduler uses it to recognize task groups and
 	control disk bandwidth allocation (proportional time slice allocation)
-	to such task groups.
+	to such task groups. It is also used by bio throttling logic in
+	block layer to implement upper limit in IO rates on a device.
 
 	This option only enables generic Block IO controller infrastructure.
-	One needs to also enable actual IO controlling logic in CFQ for it
-	to take effect. (CONFIG_CFQ_GROUP_IOSCHED=y).
+	One needs to also enable actual IO controlling logic/policy. For
+	enabling proportional weight division of disk bandwidth in CFQ seti
+	CONFIG_CFQ_GROUP_IOSCHED=y and for enabling throttling policy set
+	CONFIG_BLK_THROTTLE=y.
 
 	See Documentation/cgroups/blkio-controller.txt for more information.
 

init/do_mounts.c

@@ -58,6 +58,62 @@ static int __init readwrite(char *str)
 __setup("ro", readonly);
 __setup("rw", readwrite);
 
+#ifdef CONFIG_BLOCK
+/**
+ * match_dev_by_uuid - callback for finding a partition using its uuid
+ * @dev:	device passed in by the caller
+ * @data:	opaque pointer to a 36 byte char array with a UUID
+ *
+ * Returns 1 if the device matches, and 0 otherwise.
+ */
+static int match_dev_by_uuid(struct device *dev, void *data)
+{
+	u8 *uuid = data;
+	struct hd_struct *part = dev_to_part(dev);
+
+	if (!part->info)
+		goto no_match;
+
+	if (memcmp(uuid, part->info->uuid, sizeof(part->info->uuid)))
+			goto no_match;
+
+	return 1;
+no_match:
+	return 0;
+}
+
+
+/**
+ * devt_from_partuuid - looks up the dev_t of a partition by its UUID
+ * @uuid:	36 byte char array containing a hex ascii UUID
+ *
+ * The function will return the first partition which contains a matching
+ * UUID value in its partition_meta_info struct.  This does not search
+ * by filesystem UUIDs.
+ *
+ * Returns the matching dev_t on success or 0 on failure.
+ */
+static dev_t __init devt_from_partuuid(char *uuid_str)
+{
+	dev_t res = 0;
+	struct device *dev = NULL;
+	u8 uuid[16];
+
+	/* Pack the requested UUID in the expected format. */
+	part_pack_uuid(uuid_str, uuid);
+
+	dev = class_find_device(&block_class, NULL, uuid, &match_dev_by_uuid);
+	if (!dev)
+		goto done;
+
+	res = dev->devt;
+	put_device(dev);
+
+done:
+	return res;
+}
+#endif
+
 /*
  *	Convert a name into device number.  We accept the following variants:
  *
@@ -68,6 +124,8 @@ __setup("rw", readwrite);
  *         of partition - device number of disk plus the partition number
  *	5) /dev/<disk_name>p<decimal> - same as the above, that form is
  *	   used when disk name of partitioned disk ends on a digit.
+ *	6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
+ *	   unique id of a partition if the partition table provides it.
  *
  *	If name doesn't have fall into the categories above, we return (0,0).
  *	block_class is used to check if something is a disk name. If the disk
@@ -82,6 +140,18 @@ dev_t name_to_dev_t(char *name)
 	dev_t res = 0;
 	int part;
 
+#ifdef CONFIG_BLOCK
+	if (strncmp(name, "PARTUUID=", 9) == 0) {
+		name += 9;
+		if (strlen(name) != 36)
+			goto fail;
+		res = devt_from_partuuid(name);
+		if (!res)
+			goto fail;
+		goto done;
+	}
+#endif
+
 	if (strncmp(name, "/dev/", 5) != 0) {
 		unsigned maj, min;