From 048c9374a749a27f16493cea033fa4a8ff492356 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 18 Apr 2011 09:52:22 +0200
Subject: block: Enhance new plugging support to support general callbacks

md/raid requires an unplug callback, but as it does not uses
requests the current code cannot provide one.

So allow arbitrary callbacks to be attached to the blk_plug.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
---
 block/blk-core.c       | 20 ++++++++++++++++++++
 include/linux/blkdev.h |  7 ++++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 78b7b0cb7216..77edf0512338 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2638,6 +2638,7 @@ void blk_start_plug(struct blk_plug *plug)
 
 	plug->magic = PLUG_MAGIC;
 	INIT_LIST_HEAD(&plug->list);
+	INIT_LIST_HEAD(&plug->cb_list);
 	plug->should_sort = 0;
 
 	/*
@@ -2678,6 +2679,24 @@ static void queue_unplugged(struct request_queue *q, unsigned int depth,
 		q->unplugged_fn(q);
 }
 
+static void flush_plug_callbacks(struct blk_plug *plug)
+{
+	LIST_HEAD(callbacks);
+
+	if (list_empty(&plug->cb_list))
+		return;
+
+	list_splice_init(&plug->cb_list, &callbacks);
+
+	while (!list_empty(&callbacks)) {
+		struct blk_plug_cb *cb = list_first_entry(&callbacks,
+							  struct blk_plug_cb,
+							  list);
+		list_del(&cb->list);
+		cb->callback(cb);
+	}
+}
+
 void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 {
 	struct request_queue *q;
@@ -2688,6 +2707,7 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 
 	BUG_ON(plug->magic != PLUG_MAGIC);
 
+	flush_plug_callbacks(plug);
 	if (list_empty(&plug->list))
 		return;
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ec0357d8c4a5..f3f7879391a7 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -860,8 +860,13 @@ extern void blk_put_queue(struct request_queue *);
 struct blk_plug {
 	unsigned long magic;
 	struct list_head list;
+	struct list_head cb_list;
 	unsigned int should_sort;
 };
+struct blk_plug_cb {
+	struct list_head list;
+	void (*callback)(struct blk_plug_cb *);
+};
 
 extern void blk_start_plug(struct blk_plug *);
 extern void blk_finish_plug(struct blk_plug *);
@@ -887,7 +892,7 @@ static inline bool blk_needs_flush_plug(struct task_struct *tsk)
 {
 	struct blk_plug *plug = tsk->plug;
 
-	return plug && !list_empty(&plug->list);
+	return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
 }
 
 /*
-- 
cgit v1.2.3


From b4cb290e0a7d19235bd075c2ad4d60dbab0bac15 Mon Sep 17 00:00:00 2001
From: Jens Axboe <jaxboe@fusionio.com>
Date: Mon, 18 Apr 2011 09:54:05 +0200
Subject: Revert "block: add callback function for unplug notification"

MD can't use this since it really requires us to be able to
keep more than a single piece of state for the unplug. Commit
048c9374 added the required support for MD, so get rid of this
now unused code.

This reverts commit f75664570d8b75469cc468f23c2b27220984983b.

Conflicts:

	block/blk-core.c

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
---
 block/blk-core.c       |  3 ---
 block/blk-settings.c   | 16 ----------------
 include/linux/blkdev.h |  3 ---
 3 files changed, 22 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 77edf0512338..09b262811fff 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2674,9 +2674,6 @@ static void queue_unplugged(struct request_queue *q, unsigned int depth,
 {
 	trace_block_unplug(q, depth, !from_schedule);
 	__blk_run_queue(q, from_schedule);
-
-	if (q->unplugged_fn)
-		q->unplugged_fn(q);
 }
 
 static void flush_plug_callbacks(struct blk_plug *plug)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index eb949045bb12..1fa769293597 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -790,22 +790,6 @@ void blk_queue_flush(struct request_queue *q, unsigned int flush)
 }
 EXPORT_SYMBOL_GPL(blk_queue_flush);
 
-/**
- * blk_queue_unplugged - register a callback for an unplug event
- * @q:		the request queue for the device
- * @fn:		the function to call
- *
- * Some stacked drivers may need to know when IO is dispatched on an
- * unplug event. By registrering a callback here, they will be notified
- * when someone flushes their on-stack queue plug. The function will be
- * called with the queue lock held.
- */
-void blk_queue_unplugged(struct request_queue *q, unplugged_fn *fn)
-{
-	q->unplugged_fn = fn;
-}
-EXPORT_SYMBOL(blk_queue_unplugged);
-
 static int __init blk_settings_init(void)
 {
 	blk_max_low_pfn = max_low_pfn - 1;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f3f7879391a7..3448d89297e8 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -196,7 +196,6 @@ typedef void (request_fn_proc) (struct request_queue *q);
 typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
-typedef void (unplugged_fn) (struct request_queue *);
 
 struct bio_vec;
 struct bvec_merge_data {
@@ -284,7 +283,6 @@ struct request_queue
 	rq_timed_out_fn		*rq_timed_out_fn;
 	dma_drain_needed_fn	*dma_drain_needed;
 	lld_busy_fn		*lld_busy_fn;
-	unplugged_fn		*unplugged_fn;
 
 	/*
 	 * Dispatch queue sorting
@@ -843,7 +841,6 @@ extern void blk_queue_dma_alignment(struct request_queue *, int);
 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
-extern void blk_queue_unplugged(struct request_queue *, unplugged_fn *);
 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
-- 
cgit v1.2.3


From 99e22598e9a8e0a996d69c8c0f6b7027cb57720a Mon Sep 17 00:00:00 2001
From: Jens Axboe <jaxboe@fusionio.com>
Date: Mon, 18 Apr 2011 09:59:55 +0200
Subject: block: drop queue lock before calling __blk_run_queue() for kblockd
 punt

If we know we are going to punt to kblockd, we can drop the queue
lock before calling into __blk_run_queue() since it only does a
safe bit test and a workqueue call. Since kblockd needs to grab
this very lock as one of the first things it does, it's a good
optimization to drop the lock before waking kblockd.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
---
 block/blk-core.c | 33 +++++++++++++++++++++++++--------
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 09b262811fff..5e413933bc3a 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -295,7 +295,8 @@ EXPORT_SYMBOL(blk_sync_queue);
  *
  * Description:
  *    See @blk_run_queue. This variant must be called with the queue lock
- *    held and interrupts disabled.
+ *    held and interrupts disabled. If force_kblockd is true, then it is
+ *    safe to call this without holding the queue lock.
  *
  */
 void __blk_run_queue(struct request_queue *q, bool force_kblockd)
@@ -2671,9 +2672,23 @@ static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b)
  */
 static void queue_unplugged(struct request_queue *q, unsigned int depth,
 			    bool from_schedule)
+	__releases(q->queue_lock)
 {
 	trace_block_unplug(q, depth, !from_schedule);
-	__blk_run_queue(q, from_schedule);
+
+	/*
+	 * If we are punting this to kblockd, then we can safely drop
+	 * the queue_lock before waking kblockd (which needs to take
+	 * this lock).
+	 */
+	if (from_schedule) {
+		spin_unlock(q->queue_lock);
+		__blk_run_queue(q, true);
+	} else {
+		__blk_run_queue(q, false);
+		spin_unlock(q->queue_lock);
+	}
+
 }
 
 static void flush_plug_callbacks(struct blk_plug *plug)
@@ -2729,10 +2744,11 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 		BUG_ON(!(rq->cmd_flags & REQ_ON_PLUG));
 		BUG_ON(!rq->q);
 		if (rq->q != q) {
-			if (q) {
+			/*
+			 * This drops the queue lock
+			 */
+			if (q)
 				queue_unplugged(q, depth, from_schedule);
-				spin_unlock(q->queue_lock);
-			}
 			q = rq->q;
 			depth = 0;
 			spin_lock(q->queue_lock);
@@ -2750,10 +2766,11 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 		depth++;
 	}
 
-	if (q) {
+	/*
+	 * This drops the queue lock
+	 */
+	if (q)
 		queue_unplugged(q, depth, from_schedule);
-		spin_unlock(q->queue_lock);
-	}
 
 	local_irq_restore(flags);
 }
-- 
cgit v1.2.3


From e1dfa0a29737142c32f00a3bac0f609dc85b4a82 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 18 Apr 2011 18:25:41 +1000
Subject: md: use new plugging interface for RAID IO.

md/raid submits a lot of IO from the various raid threads.
So adding start/finish plug calls to those so that some
plugging happens.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid1.c  | 5 ++++-
 drivers/md/raid10.c | 3 +++
 drivers/md/raid5.c  | 3 +++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index c2a21ae56d97..5449cd5e3141 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1516,9 +1516,11 @@ static void raid1d(mddev_t *mddev)
 	conf_t *conf = mddev->private;
 	struct list_head *head = &conf->retry_list;
 	mdk_rdev_t *rdev;
+	struct blk_plug plug;
 
 	md_check_recovery(mddev);
-	
+
+	blk_start_plug(&plug);
 	for (;;) {
 		char b[BDEVNAME_SIZE];
 
@@ -1593,6 +1595,7 @@ static void raid1d(mddev_t *mddev)
 		}
 		cond_resched();
 	}
+	blk_finish_plug(&plug);
 }
 
 
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 2da83d566592..c8e5dac5d695 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1640,9 +1640,11 @@ static void raid10d(mddev_t *mddev)
 	conf_t *conf = mddev->private;
 	struct list_head *head = &conf->retry_list;
 	mdk_rdev_t *rdev;
+	struct blk_plug plug;
 
 	md_check_recovery(mddev);
 
+	blk_start_plug(&plug);
 	for (;;) {
 		char b[BDEVNAME_SIZE];
 
@@ -1716,6 +1718,7 @@ static void raid10d(mddev_t *mddev)
 		}
 		cond_resched();
 	}
+	blk_finish_plug(&plug);
 }
 
 
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index e867ee42b152..ce6960b1c682 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4478,11 +4478,13 @@ static void raid5d(mddev_t *mddev)
 	struct stripe_head *sh;
 	raid5_conf_t *conf = mddev->private;
 	int handled;
+	struct blk_plug plug;
 
 	pr_debug("+++ raid5d active\n");
 
 	md_check_recovery(mddev);
 
+	blk_start_plug(&plug);
 	handled = 0;
 	spin_lock_irq(&conf->device_lock);
 	while (1) {
@@ -4525,6 +4527,7 @@ static void raid5d(mddev_t *mddev)
 	spin_unlock_irq(&conf->device_lock);
 
 	async_tx_issue_pending_all();
+	blk_finish_plug(&plug);
 
 	pr_debug("--- raid5d inactive\n");
 }
-- 
cgit v1.2.3


From af1db72d8b340f97ad12b60175afdef43e6f0e60 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 18 Apr 2011 18:25:41 +1000
Subject: md/dm - remove remains of plug_fn callback.

Now that unplugging is done differently, the unplug_fn callback is
never called, so it can be completely discarded.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/dm-raid.c          | 8 --------
 include/linux/device-mapper.h | 1 -
 2 files changed, 9 deletions(-)

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 5ef136cdba91..e5d8904fc8f6 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -390,13 +390,6 @@ static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
 	return md_raid5_congested(&rs->md, bits);
 }
 
-static void raid_unplug(struct dm_target_callbacks *cb)
-{
-	struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
-
-	md_raid5_kick_device(rs->md.private);
-}
-
 /*
  * Construct a RAID4/5/6 mapping:
  * Args:
@@ -487,7 +480,6 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	}
 
 	rs->callbacks.congested_fn = raid_is_congested;
-	rs->callbacks.unplug_fn = raid_unplug;
 	dm_table_add_target_callbacks(ti->table, &rs->callbacks);
 
 	return 0;
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index e2768834f397..32a4423710f5 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -197,7 +197,6 @@ struct dm_target {
 struct dm_target_callbacks {
 	struct list_head list;
 	int (*congested_fn) (struct dm_target_callbacks *, int);
-	void (*unplug_fn)(struct dm_target_callbacks *);
 };
 
 int dm_register_target(struct target_type *t);
-- 
cgit v1.2.3


From 482c083492ddaa32ef5864bae3d143dc8bcdf7d1 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 18 Apr 2011 18:25:42 +1000
Subject: md - remove old plugging code.

md has some plugging infrastructure for RAID5 to use because the
normal plugging infrastructure required a 'request_queue', and when
called from dm, RAID5 doesn't have one of those available.

This relied on the ->unplug_fn callback which doesn't exist any more.

So remove all of that code, both in md and raid5.  Subsequent patches
with restore the plugging functionality.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/md.c    | 51 ---------------------------------------------------
 drivers/md/md.h    | 22 ----------------------
 drivers/md/raid5.c | 37 ++++++++-----------------------------
 drivers/md/raid5.h |  2 --
 4 files changed, 8 insertions(+), 104 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index b12b3776c0c0..fb11170c717e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -445,50 +445,6 @@ void md_flush_request(mddev_t *mddev, struct bio *bio)
 }
 EXPORT_SYMBOL(md_flush_request);
 
-/* Support for plugging.
- * This mirrors the plugging support in request_queue, but does not
- * require having a whole queue
- */
-static void plugger_work(struct work_struct *work)
-{
-	struct plug_handle *plug =
-		container_of(work, struct plug_handle, unplug_work);
-	plug->unplug_fn(plug);
-}
-static void plugger_timeout(unsigned long data)
-{
-	struct plug_handle *plug = (void *)data;
-	kblockd_schedule_work(NULL, &plug->unplug_work);
-}
-void plugger_init(struct plug_handle *plug,
-		  void (*unplug_fn)(struct plug_handle *))
-{
-	plug->unplug_flag = 0;
-	plug->unplug_fn = unplug_fn;
-	init_timer(&plug->unplug_timer);
-	plug->unplug_timer.function = plugger_timeout;
-	plug->unplug_timer.data = (unsigned long)plug;
-	INIT_WORK(&plug->unplug_work, plugger_work);
-}
-EXPORT_SYMBOL_GPL(plugger_init);
-
-void plugger_set_plug(struct plug_handle *plug)
-{
-	if (!test_and_set_bit(PLUGGED_FLAG, &plug->unplug_flag))
-		mod_timer(&plug->unplug_timer, jiffies + msecs_to_jiffies(3)+1);
-}
-EXPORT_SYMBOL_GPL(plugger_set_plug);
-
-int plugger_remove_plug(struct plug_handle *plug)
-{
-	if (test_and_clear_bit(PLUGGED_FLAG, &plug->unplug_flag)) {
-		del_timer(&plug->unplug_timer);
-		return 1;
-	} else
-		return 0;
-}
-EXPORT_SYMBOL_GPL(plugger_remove_plug);
-
 
 static inline mddev_t *mddev_get(mddev_t *mddev)
 {
@@ -4723,7 +4679,6 @@ static void md_clean(mddev_t *mddev)
 	mddev->bitmap_info.chunksize = 0;
 	mddev->bitmap_info.daemon_sleep = 0;
 	mddev->bitmap_info.max_write_behind = 0;
-	mddev->plug = NULL;
 }
 
 static void __md_stop_writes(mddev_t *mddev)
@@ -6688,12 +6643,6 @@ int md_allow_write(mddev_t *mddev)
 }
 EXPORT_SYMBOL_GPL(md_allow_write);
 
-void md_unplug(mddev_t *mddev)
-{
-	if (mddev->plug)
-		mddev->plug->unplug_fn(mddev->plug);
-}
-
 #define SYNC_MARKS	10
 #define	SYNC_MARK_STEP	(3*HZ)
 void md_do_sync(mddev_t *mddev)
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 52b407369e13..fad90228672f 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -29,26 +29,6 @@
 typedef struct mddev_s mddev_t;
 typedef struct mdk_rdev_s mdk_rdev_t;
 
-/* generic plugging support - like that provided with request_queue,
- * but does not require a request_queue
- */
-struct plug_handle {
-	void			(*unplug_fn)(struct plug_handle *);
-	struct timer_list	unplug_timer;
-	struct work_struct	unplug_work;
-	unsigned long		unplug_flag;
-};
-#define	PLUGGED_FLAG 1
-void plugger_init(struct plug_handle *plug,
-		  void (*unplug_fn)(struct plug_handle *));
-void plugger_set_plug(struct plug_handle *plug);
-int plugger_remove_plug(struct plug_handle *plug);
-static inline void plugger_flush(struct plug_handle *plug)
-{
-	del_timer_sync(&plug->unplug_timer);
-	cancel_work_sync(&plug->unplug_work);
-}
-
 /*
  * MD's 'extended' device
  */
@@ -336,7 +316,6 @@ struct mddev_s
 	struct list_head		all_mddevs;
 
 	struct attribute_group		*to_remove;
-	struct plug_handle		*plug; /* if used by personality */
 
 	struct bio_set			*bio_set;
 
@@ -516,7 +495,6 @@ extern int md_integrity_register(mddev_t *mddev);
 extern void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
 extern void restore_bitmap_write_access(struct file *file);
-extern void md_unplug(mddev_t *mddev);
 
 extern void mddev_init(mddev_t *mddev);
 extern int md_run(mddev_t *mddev);
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ce6960b1c682..a1755a6a3e5f 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -199,14 +199,12 @@ static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
 		BUG_ON(!list_empty(&sh->lru));
 		BUG_ON(atomic_read(&conf->active_stripes)==0);
 		if (test_bit(STRIPE_HANDLE, &sh->state)) {
-			if (test_bit(STRIPE_DELAYED, &sh->state)) {
+			if (test_bit(STRIPE_DELAYED, &sh->state))
 				list_add_tail(&sh->lru, &conf->delayed_list);
-				plugger_set_plug(&conf->plug);
-			} else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
-				   sh->bm_seq - conf->seq_write > 0) {
+			else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
+				   sh->bm_seq - conf->seq_write > 0)
 				list_add_tail(&sh->lru, &conf->bitmap_list);
-				plugger_set_plug(&conf->plug);
-			} else {
+			else {
 				clear_bit(STRIPE_BIT_DELAY, &sh->state);
 				list_add_tail(&sh->lru, &conf->handle_list);
 			}
@@ -461,7 +459,7 @@ get_active_stripe(raid5_conf_t *conf, sector_t sector,
 						     < (conf->max_nr_stripes *3/4)
 						     || !conf->inactive_blocked),
 						    conf->device_lock,
-						    md_raid5_kick_device(conf));
+						    md_wakeup_thread(conf->mddev->thread));
 				conf->inactive_blocked = 0;
 			} else
 				init_stripe(sh, sector, previous);
@@ -1470,7 +1468,7 @@ static int resize_stripes(raid5_conf_t *conf, int newsize)
 		wait_event_lock_irq(conf->wait_for_stripe,
 				    !list_empty(&conf->inactive_list),
 				    conf->device_lock,
-				    blk_flush_plug(current));
+				    );
 		osh = get_free_stripe(conf);
 		spin_unlock_irq(&conf->device_lock);
 		atomic_set(&nsh->count, 1);
@@ -3623,8 +3621,7 @@ static void raid5_activate_delayed(raid5_conf_t *conf)
 				atomic_inc(&conf->preread_active_stripes);
 			list_add_tail(&sh->lru, &conf->hold_list);
 		}
-	} else
-		plugger_set_plug(&conf->plug);
+	}
 }
 
 static void activate_bit_delay(raid5_conf_t *conf)
@@ -3641,21 +3638,6 @@ static void activate_bit_delay(raid5_conf_t *conf)
 	}
 }
 
-void md_raid5_kick_device(raid5_conf_t *conf)
-{
-	blk_flush_plug(current);
-	raid5_activate_delayed(conf);
-	md_wakeup_thread(conf->mddev->thread);
-}
-EXPORT_SYMBOL_GPL(md_raid5_kick_device);
-
-static void raid5_unplug(struct plug_handle *plug)
-{
-	raid5_conf_t *conf = container_of(plug, raid5_conf_t, plug);
-
-	md_raid5_kick_device(conf);
-}
-
 int md_raid5_congested(mddev_t *mddev, int bits)
 {
 	raid5_conf_t *conf = mddev->private;
@@ -4057,7 +4039,7 @@ static int make_request(mddev_t *mddev, struct bio * bi)
 				 * add failed due to overlap.  Flush everything
 				 * and wait a while
 				 */
-				md_raid5_kick_device(conf);
+				md_wakeup_thread(mddev->thread);
 				release_stripe(sh);
 				schedule();
 				goto retry;
@@ -5144,8 +5126,6 @@ static int run(mddev_t *mddev)
 		       mdname(mddev));
 	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
 
-	plugger_init(&conf->plug, raid5_unplug);
-	mddev->plug = &conf->plug;
 	if (mddev->queue) {
 		int chunk_size;
 		/* read-ahead size must cover two whole stripes, which
@@ -5195,7 +5175,6 @@ static int stop(mddev_t *mddev)
 	mddev->thread = NULL;
 	if (mddev->queue)
 		mddev->queue->backing_dev_info.congested_fn = NULL;
-	plugger_flush(&conf->plug); /* the unplug fn references 'conf'*/
 	free_conf(conf);
 	mddev->private = NULL;
 	mddev->to_remove = &raid5_attrs_group;
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 8d563a4f022a..3ca77a2613ba 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -400,8 +400,6 @@ struct raid5_private_data {
 					    * Cleared when a sync completes.
 					    */
 
-	struct plug_handle	plug;
-
 	/* per cpu variables */
 	struct raid5_percpu {
 		struct page	*spare_page; /* Used when checking P/Q in raid6 */
-- 
cgit v1.2.3


From 97658cdd3af7d01461874c93b89afa4a2465e7c6 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 18 Apr 2011 18:25:42 +1000
Subject: md: provide generic support for handling unplug callbacks.

When an md device adds a request to a queue, it can call
mddev_check_plugged.
If this succeeds then we know that the md thread will be woken up
shortly, and ->plug_cnt will be non-zero until then, so some
processing can be delayed.

If it fails, then no unplug callback is expected and the make_request
function needs to do whatever is required to make the request happen.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/md.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/md/md.h |  4 ++++
 2 files changed, 60 insertions(+)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index fb11170c717e..6e853c61d87e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -445,6 +445,61 @@ void md_flush_request(mddev_t *mddev, struct bio *bio)
 }
 EXPORT_SYMBOL(md_flush_request);
 
+/* Support for plugging.
+ * This mirrors the plugging support in request_queue, but does not
+ * require having a whole queue or request structures.
+ * We allocate an md_plug_cb for each md device and each thread it gets
+ * plugged on.  This links tot the private plug_handle structure in the
+ * personality data where we keep a count of the number of outstanding
+ * plugs so other code can see if a plug is active.
+ */
+struct md_plug_cb {
+	struct blk_plug_cb cb;
+	mddev_t *mddev;
+};
+
+static void plugger_unplug(struct blk_plug_cb *cb)
+{
+	struct md_plug_cb *mdcb = container_of(cb, struct md_plug_cb, cb);
+	if (atomic_dec_and_test(&mdcb->mddev->plug_cnt))
+		md_wakeup_thread(mdcb->mddev->thread);
+	kfree(mdcb);
+}
+
+/* Check that an unplug wakeup will come shortly.
+ * If not, wakeup the md thread immediately
+ */
+int mddev_check_plugged(mddev_t *mddev)
+{
+	struct blk_plug *plug = current->plug;
+	struct md_plug_cb *mdcb;
+
+	if (!plug)
+		return 0;
+
+	list_for_each_entry(mdcb, &plug->cb_list, cb.list) {
+		if (mdcb->cb.callback == plugger_unplug &&
+		    mdcb->mddev == mddev) {
+			/* Already on the list, move to top */
+			if (mdcb != list_first_entry(&plug->cb_list,
+						    struct md_plug_cb,
+						    cb.list))
+				list_move(&mdcb->cb.list, &plug->cb_list);
+			return 1;
+		}
+	}
+	/* Not currently on the callback list */
+	mdcb = kmalloc(sizeof(*mdcb), GFP_ATOMIC);
+	if (!mdcb)
+		return 0;
+
+	mdcb->mddev = mddev;
+	mdcb->cb.callback = plugger_unplug;
+	atomic_inc(&mddev->plug_cnt);
+	list_add(&mdcb->cb.list, &plug->cb_list);
+	return 1;
+}
+EXPORT_SYMBOL_GPL(mddev_check_plugged);
 
 static inline mddev_t *mddev_get(mddev_t *mddev)
 {
@@ -494,6 +549,7 @@ void mddev_init(mddev_t *mddev)
 	atomic_set(&mddev->active, 1);
 	atomic_set(&mddev->openers, 0);
 	atomic_set(&mddev->active_io, 0);
+	atomic_set(&mddev->plug_cnt, 0);
 	spin_lock_init(&mddev->write_lock);
 	atomic_set(&mddev->flush_pending, 0);
 	init_waitqueue_head(&mddev->sb_wait);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index fad90228672f..0b1fd3f1d85b 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -179,6 +179,9 @@ struct mddev_s
 	int				delta_disks, new_level, new_layout;
 	int				new_chunk_sectors;
 
+	atomic_t			plug_cnt;	/* If device is expecting
+							 * more bios soon.
+							 */
 	struct mdk_thread_s		*thread;	/* management thread */
 	struct mdk_thread_s		*sync_thread;	/* doing resync or reconstruct */
 	sector_t			curr_resync;	/* last block scheduled */
@@ -508,4 +511,5 @@ extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
 				   mddev_t *mddev);
 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
 				   mddev_t *mddev);
+extern int mddev_check_plugged(mddev_t *mddev);
 #endif /* _MD_MD_H */
-- 
cgit v1.2.3


From 7c13edc87510f665da3094174e1fd633e06649f4 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 18 Apr 2011 18:25:43 +1000
Subject: md: incorporate new plugging into raid5.

In raid5 plugging is used for 2 things:
 1/ collecting writes that require a bitmap update
 2/ collecting writes in the hope that we can create full
    stripes - or at least more-full.

We now release these different sets of stripes when plug_cnt
is zero.

Also in make_request, we call mddev_check_plug to hopefully increase
plug_cnt, and wake up the thread at the end if plugging wasn't
achieved for some reason.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid5.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index a1755a6a3e5f..f301e6ae220c 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -27,12 +27,12 @@
  *
  * We group bitmap updates into batches.  Each batch has a number.
  * We may write out several batches at once, but that isn't very important.
- * conf->bm_write is the number of the last batch successfully written.
- * conf->bm_flush is the number of the last batch that was closed to
+ * conf->seq_write is the number of the last batch successfully written.
+ * conf->seq_flush is the number of the last batch that was closed to
  *    new additions.
  * When we discover that we will need to write to any block in a stripe
  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
- * the number of the batch it will be in. This is bm_flush+1.
+ * the number of the batch it will be in. This is seq_flush+1.
  * When we are ready to do a write, if that batch hasn't been written yet,
  *   we plug the array and queue the stripe for later.
  * When an unplug happens, we increment bm_flush, thus closing the current
@@ -459,7 +459,7 @@ get_active_stripe(raid5_conf_t *conf, sector_t sector,
 						     < (conf->max_nr_stripes *3/4)
 						     || !conf->inactive_blocked),
 						    conf->device_lock,
-						    md_wakeup_thread(conf->mddev->thread));
+						    );
 				conf->inactive_blocked = 0;
 			} else
 				init_stripe(sh, sector, previous);
@@ -3927,6 +3927,7 @@ static int make_request(mddev_t *mddev, struct bio * bi)
 	struct stripe_head *sh;
 	const int rw = bio_data_dir(bi);
 	int remaining;
+	int plugged;
 
 	if (unlikely(bi->bi_rw & REQ_FLUSH)) {
 		md_flush_request(mddev, bi);
@@ -3945,6 +3946,7 @@ static int make_request(mddev_t *mddev, struct bio * bi)
 	bi->bi_next = NULL;
 	bi->bi_phys_segments = 1;	/* over-loaded to count active stripes */
 
+	plugged = mddev_check_plugged(mddev);
 	for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
 		DEFINE_WAIT(w);
 		int disks, data_disks;
@@ -4059,6 +4061,9 @@ static int make_request(mddev_t *mddev, struct bio * bi)
 		}
 			
 	}
+	if (!plugged)
+		md_wakeup_thread(mddev->thread);
+
 	spin_lock_irq(&conf->device_lock);
 	remaining = raid5_dec_bi_phys_segments(bi);
 	spin_unlock_irq(&conf->device_lock);
@@ -4472,14 +4477,18 @@ static void raid5d(mddev_t *mddev)
 	while (1) {
 		struct bio *bio;
 
-		if (conf->seq_flush != conf->seq_write) {
-			int seq = conf->seq_flush;
+		if (atomic_read(&mddev->plug_cnt) == 0 &&
+		    !list_empty(&conf->bitmap_list)) {
+			/* Now is a good time to flush some bitmap updates */
+			conf->seq_flush++;
 			spin_unlock_irq(&conf->device_lock);
 			bitmap_unplug(mddev->bitmap);
 			spin_lock_irq(&conf->device_lock);
-			conf->seq_write = seq;
+			conf->seq_write = conf->seq_flush;
 			activate_bit_delay(conf);
 		}
+		if (atomic_read(&mddev->plug_cnt) == 0)
+			raid5_activate_delayed(conf);
 
 		while ((bio = remove_bio_from_retry(conf))) {
 			int ok;
-- 
cgit v1.2.3


From c3b328ac846bcf6b9a62c5563380a81ab723006d Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 18 Apr 2011 18:25:43 +1000
Subject: md: fix up raid1/raid10 unplugging.

We just need to make sure that an unplug event wakes up the md
thread, which is exactly what mddev_check_plugged does.

Also remove some plug-related code that is no longer needed.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid1.c  | 24 ++++++++++--------------
 drivers/md/raid10.c | 24 ++++++++++--------------
 2 files changed, 20 insertions(+), 28 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 5449cd5e3141..2b7a7ff401dc 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -565,12 +565,6 @@ static void flush_pending_writes(conf_t *conf)
 		spin_unlock_irq(&conf->device_lock);
 }
 
-static void md_kick_device(mddev_t *mddev)
-{
-	blk_flush_plug(current);
-	md_wakeup_thread(mddev->thread);
-}
-
 /* Barriers....
  * Sometimes we need to suspend IO while we do something else,
  * either some resync/recovery, or reconfigure the array.
@@ -600,7 +594,7 @@ static void raise_barrier(conf_t *conf)
 
 	/* Wait until no block IO is waiting */
 	wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
-			    conf->resync_lock, md_kick_device(conf->mddev));
+			    conf->resync_lock, );
 
 	/* block any new IO from starting */
 	conf->barrier++;
@@ -608,7 +602,7 @@ static void raise_barrier(conf_t *conf)
 	/* Now wait for all pending IO to complete */
 	wait_event_lock_irq(conf->wait_barrier,
 			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
-			    conf->resync_lock, md_kick_device(conf->mddev));
+			    conf->resync_lock, );
 
 	spin_unlock_irq(&conf->resync_lock);
 }
@@ -630,7 +624,7 @@ static void wait_barrier(conf_t *conf)
 		conf->nr_waiting++;
 		wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
 				    conf->resync_lock,
-				    md_kick_device(conf->mddev));
+				    );
 		conf->nr_waiting--;
 	}
 	conf->nr_pending++;
@@ -666,8 +660,7 @@ static void freeze_array(conf_t *conf)
 	wait_event_lock_irq(conf->wait_barrier,
 			    conf->nr_pending == conf->nr_queued+1,
 			    conf->resync_lock,
-			    ({ flush_pending_writes(conf);
-			       md_kick_device(conf->mddev); }));
+			    flush_pending_writes(conf));
 	spin_unlock_irq(&conf->resync_lock);
 }
 static void unfreeze_array(conf_t *conf)
@@ -729,6 +722,7 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
 	const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
 	mdk_rdev_t *blocked_rdev;
+	int plugged;
 
 	/*
 	 * Register the new request and wait if the reconstruction
@@ -820,6 +814,8 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	 * inc refcount on their rdev.  Record them by setting
 	 * bios[x] to bio
 	 */
+	plugged = mddev_check_plugged(mddev);
+
 	disks = conf->raid_disks;
  retry_write:
 	blocked_rdev = NULL;
@@ -925,7 +921,7 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	/* In case raid1d snuck in to freeze_array */
 	wake_up(&conf->wait_barrier);
 
-	if (do_sync || !bitmap)
+	if (do_sync || !bitmap || !plugged)
 		md_wakeup_thread(mddev->thread);
 
 	return 0;
@@ -1524,7 +1520,8 @@ static void raid1d(mddev_t *mddev)
 	for (;;) {
 		char b[BDEVNAME_SIZE];
 
-		flush_pending_writes(conf);
+		if (atomic_read(&mddev->plug_cnt) == 0)
+			flush_pending_writes(conf);
 
 		spin_lock_irqsave(&conf->device_lock, flags);
 		if (list_empty(head)) {
@@ -2042,7 +2039,6 @@ static int stop(mddev_t *mddev)
 
 	md_unregister_thread(mddev->thread);
 	mddev->thread = NULL;
-	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
 	if (conf->r1bio_pool)
 		mempool_destroy(conf->r1bio_pool);
 	kfree(conf->mirrors);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index c8e5dac5d695..8e9462626ec5 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -634,12 +634,6 @@ static void flush_pending_writes(conf_t *conf)
 		spin_unlock_irq(&conf->device_lock);
 }
 
-static void md_kick_device(mddev_t *mddev)
-{
-	blk_flush_plug(current);
-	md_wakeup_thread(mddev->thread);
-}
-
 /* Barriers....
  * Sometimes we need to suspend IO while we do something else,
  * either some resync/recovery, or reconfigure the array.
@@ -669,15 +663,15 @@ static void raise_barrier(conf_t *conf, int force)
 
 	/* Wait until no block IO is waiting (unless 'force') */
 	wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
-			    conf->resync_lock, md_kick_device(conf->mddev));
+			    conf->resync_lock, );
 
 	/* block any new IO from starting */
 	conf->barrier++;
 
-	/* No wait for all pending IO to complete */
+	/* Now wait for all pending IO to complete */
 	wait_event_lock_irq(conf->wait_barrier,
 			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
-			    conf->resync_lock, md_kick_device(conf->mddev));
+			    conf->resync_lock, );
 
 	spin_unlock_irq(&conf->resync_lock);
 }
@@ -698,7 +692,7 @@ static void wait_barrier(conf_t *conf)
 		conf->nr_waiting++;
 		wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
 				    conf->resync_lock,
-				    md_kick_device(conf->mddev));
+				    );
 		conf->nr_waiting--;
 	}
 	conf->nr_pending++;
@@ -734,8 +728,8 @@ static void freeze_array(conf_t *conf)
 	wait_event_lock_irq(conf->wait_barrier,
 			    conf->nr_pending == conf->nr_queued+1,
 			    conf->resync_lock,
-			    ({ flush_pending_writes(conf);
-			       md_kick_device(conf->mddev); }));
+			    flush_pending_writes(conf));
+
 	spin_unlock_irq(&conf->resync_lock);
 }
 
@@ -762,6 +756,7 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	const unsigned long do_fua = (bio->bi_rw & REQ_FUA);
 	unsigned long flags;
 	mdk_rdev_t *blocked_rdev;
+	int plugged;
 
 	if (unlikely(bio->bi_rw & REQ_FLUSH)) {
 		md_flush_request(mddev, bio);
@@ -870,6 +865,8 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	 * inc refcount on their rdev.  Record them by setting
 	 * bios[x] to bio
 	 */
+	plugged = mddev_check_plugged(mddev);
+
 	raid10_find_phys(conf, r10_bio);
  retry_write:
 	blocked_rdev = NULL;
@@ -946,9 +943,8 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 	/* In case raid10d snuck in to freeze_array */
 	wake_up(&conf->wait_barrier);
 
-	if (do_sync || !mddev->bitmap)
+	if (do_sync || !mddev->bitmap || !plugged)
 		md_wakeup_thread(mddev->thread);
-
 	return 0;
 }
 
-- 
cgit v1.2.3


From 4521cc4ed5173f92714f6999a69910c3385fed68 Mon Sep 17 00:00:00 2001
From: Jens Axboe <jaxboe@fusionio.com>
Date: Mon, 18 Apr 2011 11:36:39 +0200
Subject: block: blk_delay_queue() should use kblockd workqueue

Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
---
 block/blk-core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 5e413933bc3a..e2bacfa46cc3 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -220,7 +220,8 @@ static void blk_delay_work(struct work_struct *work)
  */
 void blk_delay_queue(struct request_queue *q, unsigned long msecs)
 {
-	schedule_delayed_work(&q->delay_work, msecs_to_jiffies(msecs));
+	queue_delayed_work(kblockd_workqueue, &q->delay_work,
+				msecs_to_jiffies(msecs));
 }
 EXPORT_SYMBOL(blk_delay_queue);
 
-- 
cgit v1.2.3


From 24ecfbe27f65563909b14492afda2f1c21f7c044 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Mon, 18 Apr 2011 11:41:33 +0200
Subject: block: add blk_run_queue_async

Instead of overloading __blk_run_queue to force an offload to kblockd
add a new blk_run_queue_async helper to do it explicitly.  I've kept
the blk_queue_stopped check for now, but I suspect it's not needed
as the check we do when the workqueue items runs should be enough.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
---
 block/blk-core.c                 | 36 ++++++++++++++++++++++++------------
 block/blk-exec.c                 |  2 +-
 block/blk-flush.c                |  4 ++--
 block/blk.h                      |  1 +
 block/cfq-iosched.c              |  6 +++---
 block/elevator.c                 |  4 ++--
 drivers/scsi/scsi_lib.c          |  2 +-
 drivers/scsi/scsi_transport_fc.c |  2 +-
 include/linux/blkdev.h           |  2 +-
 9 files changed, 36 insertions(+), 23 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index e2bacfa46cc3..5fa3dd2705c6 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -204,7 +204,7 @@ static void blk_delay_work(struct work_struct *work)
 
 	q = container_of(work, struct request_queue, delay_work.work);
 	spin_lock_irq(q->queue_lock);
-	__blk_run_queue(q, false);
+	__blk_run_queue(q);
 	spin_unlock_irq(q->queue_lock);
 }
 
@@ -239,7 +239,7 @@ void blk_start_queue(struct request_queue *q)
 	WARN_ON(!irqs_disabled());
 
 	queue_flag_clear(QUEUE_FLAG_STOPPED, q);
-	__blk_run_queue(q, false);
+	__blk_run_queue(q);
 }
 EXPORT_SYMBOL(blk_start_queue);
 
@@ -296,11 +296,9 @@ EXPORT_SYMBOL(blk_sync_queue);
  *
  * Description:
  *    See @blk_run_queue. This variant must be called with the queue lock
- *    held and interrupts disabled. If force_kblockd is true, then it is
- *    safe to call this without holding the queue lock.
- *
+ *    held and interrupts disabled.
  */
-void __blk_run_queue(struct request_queue *q, bool force_kblockd)
+void __blk_run_queue(struct request_queue *q)
 {
 	if (unlikely(blk_queue_stopped(q)))
 		return;
@@ -309,7 +307,7 @@ void __blk_run_queue(struct request_queue *q, bool force_kblockd)
 	 * Only recurse once to avoid overrunning the stack, let the unplug
 	 * handling reinvoke the handler shortly if we already got there.
 	 */
-	if (!force_kblockd && !queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
+	if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
 		q->request_fn(q);
 		queue_flag_clear(QUEUE_FLAG_REENTER, q);
 	} else
@@ -317,6 +315,20 @@ void __blk_run_queue(struct request_queue *q, bool force_kblockd)
 }
 EXPORT_SYMBOL(__blk_run_queue);
 
+/**
+ * blk_run_queue_async - run a single device queue in workqueue context
+ * @q:	The queue to run
+ *
+ * Description:
+ *    Tells kblockd to perform the equivalent of @blk_run_queue on behalf
+ *    of us.
+ */
+void blk_run_queue_async(struct request_queue *q)
+{
+	if (likely(!blk_queue_stopped(q)))
+		queue_delayed_work(kblockd_workqueue, &q->delay_work, 0);
+}
+
 /**
  * blk_run_queue - run a single device queue
  * @q: The queue to run
@@ -330,7 +342,7 @@ void blk_run_queue(struct request_queue *q)
 	unsigned long flags;
 
 	spin_lock_irqsave(q->queue_lock, flags);
-	__blk_run_queue(q, false);
+	__blk_run_queue(q);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 EXPORT_SYMBOL(blk_run_queue);
@@ -979,7 +991,7 @@ void blk_insert_request(struct request_queue *q, struct request *rq,
 		blk_queue_end_tag(q, rq);
 
 	add_acct_request(q, rq, where);
-	__blk_run_queue(q, false);
+	__blk_run_queue(q);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 EXPORT_SYMBOL(blk_insert_request);
@@ -1323,7 +1335,7 @@ get_rq:
 	} else {
 		spin_lock_irq(q->queue_lock);
 		add_acct_request(q, req, where);
-		__blk_run_queue(q, false);
+		__blk_run_queue(q);
 out_unlock:
 		spin_unlock_irq(q->queue_lock);
 	}
@@ -2684,9 +2696,9 @@ static void queue_unplugged(struct request_queue *q, unsigned int depth,
 	 */
 	if (from_schedule) {
 		spin_unlock(q->queue_lock);
-		__blk_run_queue(q, true);
+		blk_run_queue_async(q);
 	} else {
-		__blk_run_queue(q, false);
+		__blk_run_queue(q);
 		spin_unlock(q->queue_lock);
 	}
 
diff --git a/block/blk-exec.c b/block/blk-exec.c
index 7482b7fa863b..81e31819a597 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -55,7 +55,7 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
 	WARN_ON(irqs_disabled());
 	spin_lock_irq(q->queue_lock);
 	__elv_add_request(q, rq, where);
-	__blk_run_queue(q, false);
+	__blk_run_queue(q);
 	/* the queue is stopped so it won't be plugged+unplugged */
 	if (rq->cmd_type == REQ_TYPE_PM_RESUME)
 		q->request_fn(q);
diff --git a/block/blk-flush.c b/block/blk-flush.c
index eba4a2790c6c..6c9b5e189e62 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -218,7 +218,7 @@ static void flush_end_io(struct request *flush_rq, int error)
 	 * request_fn may confuse the driver.  Always use kblockd.
 	 */
 	if (queued)
-		__blk_run_queue(q, true);
+		blk_run_queue_async(q);
 }
 
 /**
@@ -274,7 +274,7 @@ static void flush_data_end_io(struct request *rq, int error)
 	 * the comment in flush_end_io().
 	 */
 	if (blk_flush_complete_seq(rq, REQ_FSEQ_DATA, error))
-		__blk_run_queue(q, true);
+		blk_run_queue_async(q);
 }
 
 /**
diff --git a/block/blk.h b/block/blk.h
index 61263463e38e..c9df8fc3c999 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -22,6 +22,7 @@ void blk_rq_timed_out_timer(unsigned long data);
 void blk_delete_timer(struct request *);
 void blk_add_timer(struct request *);
 void __generic_unplug_device(struct request_queue *);
+void blk_run_queue_async(struct request_queue *q);
 
 /*
  * Internal atomic flags for request handling
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 3be881ec95ad..46b0a1d1d925 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3368,7 +3368,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 			    cfqd->busy_queues > 1) {
 				cfq_del_timer(cfqd, cfqq);
 				cfq_clear_cfqq_wait_request(cfqq);
-				__blk_run_queue(cfqd->queue, false);
+				__blk_run_queue(cfqd->queue);
 			} else {
 				cfq_blkiocg_update_idle_time_stats(
 						&cfqq->cfqg->blkg);
@@ -3383,7 +3383,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 		 * this new queue is RT and the current one is BE
 		 */
 		cfq_preempt_queue(cfqd, cfqq);
-		__blk_run_queue(cfqd->queue, false);
+		__blk_run_queue(cfqd->queue);
 	}
 }
 
@@ -3743,7 +3743,7 @@ static void cfq_kick_queue(struct work_struct *work)
 	struct request_queue *q = cfqd->queue;
 
 	spin_lock_irq(q->queue_lock);
-	__blk_run_queue(cfqd->queue, false);
+	__blk_run_queue(cfqd->queue);
 	spin_unlock_irq(q->queue_lock);
 }
 
diff --git a/block/elevator.c b/block/elevator.c
index 0cdb4e7ebab4..6f6abc08bb56 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -642,7 +642,7 @@ void elv_quiesce_start(struct request_queue *q)
 	 */
 	elv_drain_elevator(q);
 	while (q->rq.elvpriv) {
-		__blk_run_queue(q, false);
+		__blk_run_queue(q);
 		spin_unlock_irq(q->queue_lock);
 		msleep(10);
 		spin_lock_irq(q->queue_lock);
@@ -695,7 +695,7 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where)
 		 *   with anything.  There's no point in delaying queue
 		 *   processing.
 		 */
-		__blk_run_queue(q, false);
+		__blk_run_queue(q);
 		break;
 
 	case ELEVATOR_INSERT_SORT_MERGE:
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 6d5c7ff43f5b..ab55c2fa7ce2 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -443,7 +443,7 @@ static void scsi_run_queue(struct request_queue *q)
 					&sdev->request_queue->queue_flags);
 		if (flagset)
 			queue_flag_set(QUEUE_FLAG_REENTER, sdev->request_queue);
-		__blk_run_queue(sdev->request_queue, false);
+		__blk_run_queue(sdev->request_queue);
 		if (flagset)
 			queue_flag_clear(QUEUE_FLAG_REENTER, sdev->request_queue);
 		spin_unlock(sdev->request_queue->queue_lock);
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index fdf3fa639056..28c33506e4ad 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -3829,7 +3829,7 @@ fc_bsg_goose_queue(struct fc_rport *rport)
 		  !test_bit(QUEUE_FLAG_REENTER, &rport->rqst_q->queue_flags);
 	if (flagset)
 		queue_flag_set(QUEUE_FLAG_REENTER, rport->rqst_q);
-	__blk_run_queue(rport->rqst_q, false);
+	__blk_run_queue(rport->rqst_q);
 	if (flagset)
 		queue_flag_clear(QUEUE_FLAG_REENTER, rport->rqst_q);
 	spin_unlock_irqrestore(rport->rqst_q->queue_lock, flags);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 3448d89297e8..cbbfd98ad4a3 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -697,7 +697,7 @@ extern void blk_start_queue(struct request_queue *q);
 extern void blk_stop_queue(struct request_queue *q);
 extern void blk_sync_queue(struct request_queue *q);
 extern void __blk_stop_queue(struct request_queue *q);
-extern void __blk_run_queue(struct request_queue *q, bool force_kblockd);
+extern void __blk_run_queue(struct request_queue *q);
 extern void blk_run_queue(struct request_queue *);
 extern int blk_rq_map_user(struct request_queue *, struct request *,
 			   struct rq_map_data *, void __user *, unsigned long,
-- 
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