Merge branch 'for-2.6.39/stack-plug' into for-2.6.39/core

Conflicts:
	block/blk-core.c
	block/blk-flush.c
	drivers/md/raid1.c
	drivers/md/raid10.c
	drivers/md/raid5.c
	fs/nilfs2/btnode.c
	fs/nilfs2/mdt.c

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

16 files changed, 63 insertions, 386 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 9a35320fb59f..ca203cb23f3c 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -347,7 +347,7 @@ static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 			atomic_inc(&bitmap->pending_writes);
 			set_buffer_locked(bh);
 			set_buffer_mapped(bh);
-			submit_bh(WRITE | REQ_UNPLUG | REQ_SYNC, bh);
+			submit_bh(WRITE | REQ_SYNC, bh);
 			bh = bh->b_this_page;
 		}
 
@@ -1339,8 +1339,7 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
 			prepare_to_wait(&bitmap->overflow_wait, &__wait,
 					TASK_UNINTERRUPTIBLE);
 			spin_unlock_irq(&bitmap->lock);
-			md_unplug(bitmap->mddev);
-			schedule();
+			io_schedule();
 			finish_wait(&bitmap->overflow_wait, &__wait);
 			continue;
 		}
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 4e054bd91664..2c62c1169f78 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -991,11 +991,6 @@ static void clone_init(struct dm_crypt_io *io, struct bio *clone)
 	clone->bi_destructor = dm_crypt_bio_destructor;
 }
 
-static void kcryptd_unplug(struct crypt_config *cc)
-{
-	blk_unplug(bdev_get_queue(cc->dev->bdev));
-}
-
 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
 {
 	struct crypt_config *cc = io->target->private;
@@ -1008,10 +1003,8 @@ static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
 	 * one in order to decrypt the whole bio data *afterwards*.
 	 */
 	clone = bio_alloc_bioset(gfp, bio_segments(base_bio), cc->bs);
-	if (!clone) {
-		kcryptd_unplug(cc);
+	if (!clone)
 		return 1;
-	}
 
 	crypt_inc_pending(io);
 
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 136d4f71a116..76a5af00a26b 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -352,7 +352,7 @@ static void dispatch_io(int rw, unsigned int num_regions,
 	BUG_ON(num_regions > DM_IO_MAX_REGIONS);
 
 	if (sync)
-		rw |= REQ_SYNC | REQ_UNPLUG;
+		rw |= REQ_SYNC;
 
 	/*
 	 * For multiple regions we need to be careful to rewind
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index 924f5f0084c2..1bb73a13ca40 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -37,13 +37,6 @@ struct dm_kcopyd_client {
 	unsigned int nr_pages;
 	unsigned int nr_free_pages;
 
-	/*
-	 * Block devices to unplug.
-	 * Non-NULL pointer means that a block device has some pending requests
-	 * and needs to be unplugged.
-	 */
-	struct block_device *unplug[2];
-
 	struct dm_io_client *io_client;
 
 	wait_queue_head_t destroyq;
@@ -315,31 +308,6 @@ static int run_complete_job(struct kcopyd_job *job)
 	return 0;
 }
 
-/*
- * Unplug the block device at the specified index.
- */
-static void unplug(struct dm_kcopyd_client *kc, int rw)
-{
-	if (kc->unplug[rw] != NULL) {
-		blk_unplug(bdev_get_queue(kc->unplug[rw]));
-		kc->unplug[rw] = NULL;
-	}
-}
-
-/*
- * Prepare block device unplug. If there's another device
- * to be unplugged at the same array index, we unplug that
- * device first.
- */
-static void prepare_unplug(struct dm_kcopyd_client *kc, int rw,
-			   struct block_device *bdev)
-{
-	if (likely(kc->unplug[rw] == bdev))
-		return;
-	unplug(kc, rw);
-	kc->unplug[rw] = bdev;
-}
-
 static void complete_io(unsigned long error, void *context)
 {
 	struct kcopyd_job *job = (struct kcopyd_job *) context;
@@ -386,16 +354,10 @@ static int run_io_job(struct kcopyd_job *job)
 		.client = job->kc->io_client,
 	};
 
-	if (job->rw == READ) {
+	if (job->rw == READ)
 		r = dm_io(&io_req, 1, &job->source, NULL);
-		prepare_unplug(job->kc, READ, job->source.bdev);
-	} else {
-		if (job->num_dests > 1)
-			io_req.bi_rw |= REQ_UNPLUG;
+	else
 		r = dm_io(&io_req, job->num_dests, job->dests, NULL);
-		if (!(io_req.bi_rw & REQ_UNPLUG))
-			prepare_unplug(job->kc, WRITE, job->dests[0].bdev);
-	}
 
 	return r;
 }
@@ -466,6 +428,7 @@ static void do_work(struct work_struct *work)
 {
 	struct dm_kcopyd_client *kc = container_of(work,
 					struct dm_kcopyd_client, kcopyd_work);
+	struct blk_plug plug;
 
 	/*
 	 * The order that these are called is *very* important.
@@ -473,18 +436,12 @@ static void do_work(struct work_struct *work)
 	 * Pages jobs when successful will jump onto the io jobs
 	 * list.  io jobs call wake when they complete and it all
 	 * starts again.
-	 *
-	 * Note that io_jobs add block devices to the unplug array,
-	 * this array is cleared with "unplug" calls. It is thus
-	 * forbidden to run complete_jobs after io_jobs and before
-	 * unplug because the block device could be destroyed in
-	 * job completion callback.
 	 */
+	blk_start_plug(&plug);
 	process_jobs(&kc->complete_jobs, kc, run_complete_job);
 	process_jobs(&kc->pages_jobs, kc, run_pages_job);
 	process_jobs(&kc->io_jobs, kc, run_io_job);
-	unplug(kc, READ);
-	unplug(kc, WRITE);
+	blk_finish_plug(&plug);
 }
 
 /*
@@ -665,8 +622,6 @@ int dm_kcopyd_client_create(unsigned int nr_pages,
 	INIT_LIST_HEAD(&kc->io_jobs);
 	INIT_LIST_HEAD(&kc->pages_jobs);
 
-	memset(kc->unplug, 0, sizeof(kc->unplug));
-
 	kc->job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache);
 	if (!kc->job_pool)
 		goto bad_slab;
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index b9e1e15ef11c..5ef136cdba91 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -394,7 +394,7 @@ static void raid_unplug(struct dm_target_callbacks *cb)
 {
 	struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
 
-	md_raid5_unplug_device(rs->md.private);
+	md_raid5_kick_device(rs->md.private);
 }
 
 /*
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index dee326775c60..976ad4688afc 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -842,8 +842,6 @@ static void do_mirror(struct work_struct *work)
 	do_reads(ms, &reads);
 	do_writes(ms, &writes);
 	do_failures(ms, &failures);
-
-	dm_table_unplug_all(ms->ti->table);
 }
 
 /*-----------------------------------------------------------------
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 38e4eb1bb965..f50a7b952257 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1275,29 +1275,6 @@ int dm_table_any_busy_target(struct dm_table *t)
 	return 0;
 }
 
-void dm_table_unplug_all(struct dm_table *t)
-{
-	struct dm_dev_internal *dd;
-	struct list_head *devices = dm_table_get_devices(t);
-	struct dm_target_callbacks *cb;
-
-	list_for_each_entry(dd, devices, list) {
-		struct request_queue *q = bdev_get_queue(dd->dm_dev.bdev);
-		char b[BDEVNAME_SIZE];
-
-		if (likely(q))
-			blk_unplug(q);
-		else
-			DMWARN_LIMIT("%s: Cannot unplug nonexistent device %s",
-				     dm_device_name(t->md),
-				     bdevname(dd->dm_dev.bdev, b));
-	}
-
-	list_for_each_entry(cb, &t->target_callbacks, list)
-		if (cb->unplug_fn)
-			cb->unplug_fn(cb);
-}
-
 struct mapped_device *dm_table_get_md(struct dm_table *t)
 {
 	return t->md;
@@ -1345,4 +1322,3 @@ EXPORT_SYMBOL(dm_table_get_mode);
 EXPORT_SYMBOL(dm_table_get_md);
 EXPORT_SYMBOL(dm_table_put);
 EXPORT_SYMBOL(dm_table_get);
-EXPORT_SYMBOL(dm_table_unplug_all);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index eaa3af0e0632..d22b9905c168 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -807,8 +807,6 @@ void dm_requeue_unmapped_request(struct request *clone)
 	dm_unprep_request(rq);
 
 	spin_lock_irqsave(q->queue_lock, flags);
-	if (elv_queue_empty(q))
-		blk_plug_device(q);
 	blk_requeue_request(q, rq);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 
@@ -1613,10 +1611,10 @@ static void dm_request_fn(struct request_queue *q)
 	 * number of in-flight I/Os after the queue is stopped in
 	 * dm_suspend().
 	 */
-	while (!blk_queue_plugged(q) && !blk_queue_stopped(q)) {
+	while (!blk_queue_stopped(q)) {
 		rq = blk_peek_request(q);
 		if (!rq)
-			goto plug_and_out;
+			goto delay_and_out;
 
 		/* always use block 0 to find the target for flushes for now */
 		pos = 0;
@@ -1627,7 +1625,7 @@ static void dm_request_fn(struct request_queue *q)
 		BUG_ON(!dm_target_is_valid(ti));
 
 		if (ti->type->busy && ti->type->busy(ti))
-			goto plug_and_out;
+			goto delay_and_out;
 
 		blk_start_request(rq);
 		clone = rq->special;
@@ -1647,11 +1645,8 @@ requeued:
 	BUG_ON(!irqs_disabled());
 	spin_lock(q->queue_lock);
 
-plug_and_out:
-	if (!elv_queue_empty(q))
-		/* Some requests still remain, retry later */
-		blk_plug_device(q);
-
+delay_and_out:
+	blk_delay_queue(q, HZ / 10);
 out:
 	dm_table_put(map);
 
@@ -1680,20 +1675,6 @@ static int dm_lld_busy(struct request_queue *q)
 	return r;
 }
 
-static void dm_unplug_all(struct request_queue *q)
-{
-	struct mapped_device *md = q->queuedata;
-	struct dm_table *map = dm_get_live_table(md);
-
-	if (map) {
-		if (dm_request_based(md))
-			generic_unplug_device(q);
-
-		dm_table_unplug_all(map);
-		dm_table_put(map);
-	}
-}
-
 static int dm_any_congested(void *congested_data, int bdi_bits)
 {
 	int r = bdi_bits;
@@ -1817,7 +1798,6 @@ static void dm_init_md_queue(struct mapped_device *md)
 	md->queue->backing_dev_info.congested_data = md;
 	blk_queue_make_request(md->queue, dm_request);
 	blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
-	md->queue->unplug_fn = dm_unplug_all;
 	blk_queue_merge_bvec(md->queue, dm_merge_bvec);
 	blk_queue_flush(md->queue, REQ_FLUSH | REQ_FUA);
 }
@@ -2263,8 +2243,6 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
 	int r = 0;
 	DECLARE_WAITQUEUE(wait, current);
 
-	dm_unplug_all(md->queue);
-
 	add_wait_queue(&md->wait, &wait);
 
 	while (1) {
@@ -2539,7 +2517,6 @@ int dm_resume(struct mapped_device *md)
 
 	clear_bit(DMF_SUSPENDED, &md->flags);
 
-	dm_table_unplug_all(map);
 	r = 0;
 out:
 	dm_table_put(map);
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 0ed7f6bc2a7f..338804f8fb3b 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -87,22 +87,6 @@ static int linear_mergeable_bvec(struct request_queue *q,
 	return maxsectors << 9;
 }
 
-static void linear_unplug(struct request_queue *q)
-{
-	mddev_t *mddev = q->queuedata;
-	linear_conf_t *conf;
-	int i;
-
-	rcu_read_lock();
-	conf = rcu_dereference(mddev->private);
-
-	for (i=0; i < mddev->raid_disks; i++) {
-		struct request_queue *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev);
-		blk_unplug(r_queue);
-	}
-	rcu_read_unlock();
-}
-
 static int linear_congested(void *data, int bits)
 {
 	mddev_t *mddev = data;
@@ -224,7 +208,6 @@ static int linear_run (mddev_t *mddev)
 	md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
 
 	blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
-	mddev->queue->unplug_fn = linear_unplug;
 	mddev->queue->backing_dev_info.congested_fn = linear_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 	md_integrity_register(mddev);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 818313e277e7..86ba66c0b28a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -780,8 +780,7 @@ void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
 	bio->bi_end_io = super_written;
 
 	atomic_inc(&mddev->pending_writes);
-	submit_bio(REQ_WRITE | REQ_SYNC | REQ_UNPLUG | REQ_FLUSH | REQ_FUA,
-		   bio);
+	submit_bio(REQ_WRITE | REQ_SYNC | REQ_FLUSH | REQ_FUA, bio);
 }
 
 void md_super_wait(mddev_t *mddev)
@@ -809,7 +808,7 @@ int sync_page_io(mdk_rdev_t *rdev, sector_t sector, int size,
 	struct completion event;
 	int ret;
 
-	rw |= REQ_SYNC | REQ_UNPLUG;
+	rw |= REQ_SYNC;
 
 	bio->bi_bdev = (metadata_op && rdev->meta_bdev) ?
 		rdev->meta_bdev : rdev->bdev;
@@ -4817,7 +4816,6 @@ static int do_md_stop(mddev_t * mddev, int mode, int is_open)
 		__md_stop_writes(mddev);
 		md_stop(mddev);
 		mddev->queue->merge_bvec_fn = NULL;
-		mddev->queue->unplug_fn = NULL;
 		mddev->queue->backing_dev_info.congested_fn = NULL;
 
 		/* tell userspace to handle 'inactive' */
@@ -6692,8 +6690,6 @@ EXPORT_SYMBOL_GPL(md_allow_write);
 
 void md_unplug(mddev_t *mddev)
 {
-	if (mddev->queue)
-		blk_unplug(mddev->queue);
 	if (mddev->plug)
 		mddev->plug->unplug_fn(mddev->plug);
 }
@@ -6876,7 +6872,6 @@ void md_do_sync(mddev_t *mddev)
 		     >= mddev->resync_max - mddev->curr_resync_completed
 			    )) {
 			/* time to update curr_resync_completed */
-			md_unplug(mddev);
 			wait_event(mddev->recovery_wait,
 				   atomic_read(&mddev->recovery_active) == 0);
 			mddev->curr_resync_completed = j;
@@ -6952,7 +6947,6 @@ void md_do_sync(mddev_t *mddev)
 		 * about not overloading the IO subsystem. (things like an
 		 * e2fsck being done on the RAID array should execute fast)
 		 */
-		md_unplug(mddev);
 		cond_resched();
 
 		currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
@@ -6971,8 +6965,6 @@ void md_do_sync(mddev_t *mddev)
 	 * this also signals 'finished resyncing' to md_stop
 	 */
  out:
-	md_unplug(mddev);
-
 	wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
 
 	/* tell personality that we are finished */
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 3a62d440e27b..5e694b151c30 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -106,36 +106,6 @@ static void multipath_end_request(struct bio *bio, int error)
 	rdev_dec_pending(rdev, conf->mddev);
 }
 
-static void unplug_slaves(mddev_t *mddev)
-{
-	multipath_conf_t *conf = mddev->private;
-	int i;
-
-	rcu_read_lock();
-	for (i=0; i<mddev->raid_disks; i++) {
-		mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev);
-		if (rdev && !test_bit(Faulty, &rdev->flags)
-		    && atomic_read(&rdev->nr_pending)) {
-			struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
-
-			atomic_inc(&rdev->nr_pending);
-			rcu_read_unlock();
-
-			blk_unplug(r_queue);
-
-			rdev_dec_pending(rdev, mddev);
-			rcu_read_lock();
-		}
-	}
-	rcu_read_unlock();
-}
-
-static void multipath_unplug(struct request_queue *q)
-{
-	unplug_slaves(q->queuedata);
-}
-
-
 static int multipath_make_request(mddev_t *mddev, struct bio * bio)
 {
 	multipath_conf_t *conf = mddev->private;
@@ -517,7 +487,6 @@ static int multipath_run (mddev_t *mddev)
 	 */
 	md_set_array_sectors(mddev, multipath_size(mddev, 0, 0));
 
-	mddev->queue->unplug_fn = multipath_unplug;
 	mddev->queue->backing_dev_info.congested_fn = multipath_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 	md_integrity_register(mddev);
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index c0ac457f1218..95916fd6394a 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -25,21 +25,6 @@
 #include "raid0.h"
 #include "raid5.h"
 
-static void raid0_unplug(struct request_queue *q)
-{
-	mddev_t *mddev = q->queuedata;
-	raid0_conf_t *conf = mddev->private;
-	mdk_rdev_t **devlist = conf->devlist;
-	int raid_disks = conf->strip_zone[0].nb_dev;
-	int i;
-
-	for (i=0; i < raid_disks; i++) {
-		struct request_queue *r_queue = bdev_get_queue(devlist[i]->bdev);
-
-		blk_unplug(r_queue);
-	}
-}
-
 static int raid0_congested(void *data, int bits)
 {
 	mddev_t *mddev = data;
@@ -272,7 +257,6 @@ static int create_strip_zones(mddev_t *mddev, raid0_conf_t **private_conf)
 		       mdname(mddev),
 		       (unsigned long long)smallest->sectors);
 	}
-	mddev->queue->unplug_fn = raid0_unplug;
 	mddev->queue->backing_dev_info.congested_fn = raid0_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 06cd712807d0..8f34ad5c478b 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -52,23 +52,16 @@
 #define	NR_RAID1_BIOS 256
 
 
-static void unplug_slaves(mddev_t *mddev);
-
 static void allow_barrier(conf_t *conf);
 static void lower_barrier(conf_t *conf);
 
 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
 {
 	struct pool_info *pi = data;
-	r1bio_t *r1_bio;
 	int size = offsetof(r1bio_t, bios[pi->raid_disks]);
 
 	/* allocate a r1bio with room for raid_disks entries in the bios array */
-	r1_bio = kzalloc(size, gfp_flags);
-	if (!r1_bio && pi->mddev)
-		unplug_slaves(pi->mddev);
-
-	return r1_bio;
+	return kzalloc(size, gfp_flags);
 }
 
 static void r1bio_pool_free(void *r1_bio, void *data)
@@ -91,10 +84,8 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
 	int i, j;
 
 	r1_bio = r1bio_pool_alloc(gfp_flags, pi);
-	if (!r1_bio) {
-		unplug_slaves(pi->mddev);
+	if (!r1_bio)
 		return NULL;
-	}
 
 	/*
 	 * Allocate bios : 1 for reading, n-1 for writing
@@ -520,37 +511,6 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio)
 	return new_disk;
 }
 
-static void unplug_slaves(mddev_t *mddev)
-{
-	conf_t *conf = mddev->private;
-	int i;
-
-	rcu_read_lock();
-	for (i=0; i<mddev->raid_disks; i++) {
-		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
-		if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
-			struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
-
-			atomic_inc(&rdev->nr_pending);
-			rcu_read_unlock();
-
-			blk_unplug(r_queue);
-
-			rdev_dec_pending(rdev, mddev);
-			rcu_read_lock();
-		}
-	}
-	rcu_read_unlock();
-}
-
-static void raid1_unplug(struct request_queue *q)
-{
-	mddev_t *mddev = q->queuedata;
-
-	unplug_slaves(mddev);
-	md_wakeup_thread(mddev->thread);
-}
-
 static int raid1_congested(void *data, int bits)
 {
 	mddev_t *mddev = data;
@@ -580,23 +540,16 @@ static int raid1_congested(void *data, int bits)
 }
 
 
-static int flush_pending_writes(conf_t *conf)
+static void flush_pending_writes(conf_t *conf)
 {
 	/* Any writes that have been queued but are awaiting
 	 * bitmap updates get flushed here.
-	 * We return 1 if any requests were actually submitted.
 	 */
-	int rv = 0;
-
 	spin_lock_irq(&conf->device_lock);
 
 	if (conf->pending_bio_list.head) {
 		struct bio *bio;
 		bio = bio_list_get(&conf->pending_bio_list);
-		/* Only take the spinlock to quiet a warning */
-		spin_lock(conf->mddev->queue->queue_lock);
-		blk_remove_plug(conf->mddev->queue);
-		spin_unlock(conf->mddev->queue->queue_lock);
 		spin_unlock_irq(&conf->device_lock);
 		/* flush any pending bitmap writes to
 		 * disk before proceeding w/ I/O */
@@ -608,10 +561,14 @@ static int flush_pending_writes(conf_t *conf)
 			generic_make_request(bio);
 			bio = next;
 		}
-		rv = 1;
 	} else
 		spin_unlock_irq(&conf->device_lock);
-	return rv;
+}
+
+static void md_kick_device(mddev_t *mddev)
+{
+	blk_flush_plug(current);
+	md_wakeup_thread(mddev->thread);
 }
 
 /* Barriers....
@@ -643,8 +600,7 @@ 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,
-			    raid1_unplug(conf->mddev->queue));
+			    conf->resync_lock, md_kick_device(conf->mddev));
 
 	/* block any new IO from starting */
 	conf->barrier++;
@@ -652,8 +608,7 @@ 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,
-			    raid1_unplug(conf->mddev->queue));
+			    conf->resync_lock, md_kick_device(conf->mddev));
 
 	spin_unlock_irq(&conf->resync_lock);
 }
@@ -675,7 +630,7 @@ static void wait_barrier(conf_t *conf)
 		conf->nr_waiting++;
 		wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
 				    conf->resync_lock,
-				    raid1_unplug(conf->mddev->queue));
+				    md_kick_device(conf->mddev));
 		conf->nr_waiting--;
 	}
 	conf->nr_pending++;
@@ -712,7 +667,7 @@ static void freeze_array(conf_t *conf)
 			    conf->nr_pending == conf->nr_queued+1,
 			    conf->resync_lock,
 			    ({ flush_pending_writes(conf);
-			       raid1_unplug(conf->mddev->queue); }));
+			       md_kick_device(conf->mddev); }));
 	spin_unlock_irq(&conf->resync_lock);
 }
 static void unfreeze_array(conf_t *conf)
@@ -962,7 +917,6 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 		atomic_inc(&r1_bio->remaining);
 		spin_lock_irqsave(&conf->device_lock, flags);
 		bio_list_add(&conf->pending_bio_list, mbio);
-		blk_plug_device_unlocked(mddev->queue);
 		spin_unlock_irqrestore(&conf->device_lock, flags);
 	}
 	r1_bio_write_done(r1_bio, bio->bi_vcnt, behind_pages, behind_pages != NULL);
@@ -971,7 +925,7 @@ 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)
+	if (do_sync || !bitmap)
 		md_wakeup_thread(mddev->thread);
 
 	return 0;
@@ -1561,7 +1515,6 @@ static void raid1d(mddev_t *mddev)
 	unsigned long flags;
 	conf_t *conf = mddev->private;
 	struct list_head *head = &conf->retry_list;
-	int unplug=0;
 	mdk_rdev_t *rdev;
 
 	md_check_recovery(mddev);
@@ -1569,7 +1522,7 @@ static void raid1d(mddev_t *mddev)
 	for (;;) {
 		char b[BDEVNAME_SIZE];
 
-		unplug += flush_pending_writes(conf);
+		flush_pending_writes(conf);
 
 		spin_lock_irqsave(&conf->device_lock, flags);
 		if (list_empty(head)) {
@@ -1583,10 +1536,9 @@ static void raid1d(mddev_t *mddev)
 
 		mddev = r1_bio->mddev;
 		conf = mddev->private;
-		if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
+		if (test_bit(R1BIO_IsSync, &r1_bio->state))
 			sync_request_write(mddev, r1_bio);
-			unplug = 1;
-		} else {
+		else {
 			int disk;
 
 			/* we got a read error. Maybe the drive is bad.  Maybe just
@@ -1636,14 +1588,11 @@ static void raid1d(mddev_t *mddev)
 				bio->bi_end_io = raid1_end_read_request;
 				bio->bi_rw = READ | do_sync;
 				bio->bi_private = r1_bio;
-				unplug = 1;
 				generic_make_request(bio);
 			}
 		}
 		cond_resched();
 	}
-	if (unplug)
-		unplug_slaves(mddev);
 }
 
 
@@ -2066,7 +2015,6 @@ static int run(mddev_t *mddev)
 
 	md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
 
-	mddev->queue->unplug_fn = raid1_unplug;
 	mddev->queue->backing_dev_info.congested_fn = raid1_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 	md_integrity_register(mddev);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 747d061d8e05..c0d0f5f7e407 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -57,23 +57,16 @@
  */
 #define	NR_RAID10_BIOS 256
 
-static void unplug_slaves(mddev_t *mddev);
-
 static void allow_barrier(conf_t *conf);
 static void lower_barrier(conf_t *conf);
 
 static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
 {
 	conf_t *conf = data;
-	r10bio_t *r10_bio;
 	int size = offsetof(struct r10bio_s, devs[conf->copies]);
 
 	/* allocate a r10bio with room for raid_disks entries in the bios array */
-	r10_bio = kzalloc(size, gfp_flags);
-	if (!r10_bio && conf->mddev)
-		unplug_slaves(conf->mddev);
-
-	return r10_bio;
+	return kzalloc(size, gfp_flags);
 }
 
 static void r10bio_pool_free(void *r10_bio, void *data)
@@ -106,10 +99,8 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
 	int nalloc;
 
 	r10_bio = r10bio_pool_alloc(gfp_flags, conf);
-	if (!r10_bio) {
-		unplug_slaves(conf->mddev);
+	if (!r10_bio)
 		return NULL;
-	}
 
 	if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
 		nalloc = conf->copies; /* resync */
@@ -597,37 +588,6 @@ rb_out:
 	return disk;
 }
 
-static void unplug_slaves(mddev_t *mddev)
-{
-	conf_t *conf = mddev->private;
-	int i;
-
-	rcu_read_lock();
-	for (i=0; i < conf->raid_disks; i++) {
-		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
-		if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
-			struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
-
-			atomic_inc(&rdev->nr_pending);
-			rcu_read_unlock();
-
-			blk_unplug(r_queue);
-
-			rdev_dec_pending(rdev, mddev);
-			rcu_read_lock();
-		}
-	}
-	rcu_read_unlock();
-}
-
-static void raid10_unplug(struct request_queue *q)
-{
-	mddev_t *mddev = q->queuedata;
-
-	unplug_slaves(q->queuedata);
-	md_wakeup_thread(mddev->thread);
-}
-
 static int raid10_congested(void *data, int bits)
 {
 	mddev_t *mddev = data;
@@ -649,23 +609,16 @@ static int raid10_congested(void *data, int bits)
 	return ret;
 }
 
-static int flush_pending_writes(conf_t *conf)
+static void flush_pending_writes(conf_t *conf)
 {
 	/* Any writes that have been queued but are awaiting
 	 * bitmap updates get flushed here.
-	 * We return 1 if any requests were actually submitted.
 	 */
-	int rv = 0;
-
 	spin_lock_irq(&conf->device_lock);
 
 	if (conf->pending_bio_list.head) {
 		struct bio *bio;
 		bio = bio_list_get(&conf->pending_bio_list);
-		/* Spinlock only taken to quiet a warning */
-		spin_lock(conf->mddev->queue->queue_lock);
-		blk_remove_plug(conf->mddev->queue);
-		spin_unlock(conf->mddev->queue->queue_lock);
 		spin_unlock_irq(&conf->device_lock);
 		/* flush any pending bitmap writes to disk
 		 * before proceeding w/ I/O */
@@ -677,11 +630,16 @@ static int flush_pending_writes(conf_t *conf)
 			generic_make_request(bio);
 			bio = next;
 		}
-		rv = 1;
 	} else
 		spin_unlock_irq(&conf->device_lock);
-	return rv;
 }
+
+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.
@@ -711,8 +669,7 @@ 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,
-			    raid10_unplug(conf->mddev->queue));
+			    conf->resync_lock, md_kick_device(conf->mddev));
 
 	/* block any new IO from starting */
 	conf->barrier++;
@@ -720,8 +677,7 @@ static void raise_barrier(conf_t *conf, int force)
 	/* No wait for all pending IO to complete */
 	wait_event_lock_irq(conf->wait_barrier,
 			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
-			    conf->resync_lock,
-			    raid10_unplug(conf->mddev->queue));
+			    conf->resync_lock, md_kick_device(conf->mddev));
 
 	spin_unlock_irq(&conf->resync_lock);
 }
@@ -742,7 +698,7 @@ static void wait_barrier(conf_t *conf)
 		conf->nr_waiting++;
 		wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
 				    conf->resync_lock,
-				    raid10_unplug(conf->mddev->queue));
+				    md_kick_device(conf->mddev));
 		conf->nr_waiting--;
 	}
 	conf->nr_pending++;
@@ -779,7 +735,7 @@ static void freeze_array(conf_t *conf)
 			    conf->nr_pending == conf->nr_queued+1,
 			    conf->resync_lock,
 			    ({ flush_pending_writes(conf);
-			       raid10_unplug(conf->mddev->queue); }));
+			       md_kick_device(conf->mddev); }));
 	spin_unlock_irq(&conf->resync_lock);
 }
 
@@ -974,7 +930,6 @@ static int make_request(mddev_t *mddev, struct bio * bio)
 		atomic_inc(&r10_bio->remaining);
 		spin_lock_irqsave(&conf->device_lock, flags);
 		bio_list_add(&conf->pending_bio_list, mbio);
-		blk_plug_device_unlocked(mddev->queue);
 		spin_unlock_irqrestore(&conf->device_lock, flags);
 	}
 
@@ -991,7 +946,7 @@ 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)
+	if (do_sync || !mddev->bitmap)
 		md_wakeup_thread(mddev->thread);
 
 	return 0;
@@ -1684,7 +1639,6 @@ static void raid10d(mddev_t *mddev)
 	unsigned long flags;
 	conf_t *conf = mddev->private;
 	struct list_head *head = &conf->retry_list;
-	int unplug=0;
 	mdk_rdev_t *rdev;
 
 	md_check_recovery(mddev);
@@ -1692,7 +1646,7 @@ static void raid10d(mddev_t *mddev)
 	for (;;) {
 		char b[BDEVNAME_SIZE];
 
-		unplug += flush_pending_writes(conf);
+		flush_pending_writes(conf);
 
 		spin_lock_irqsave(&conf->device_lock, flags);
 		if (list_empty(head)) {
@@ -1706,13 +1660,11 @@ static void raid10d(mddev_t *mddev)
 
 		mddev = r10_bio->mddev;
 		conf = mddev->private;
-		if (test_bit(R10BIO_IsSync, &r10_bio->state)) {
+		if (test_bit(R10BIO_IsSync, &r10_bio->state))
 			sync_request_write(mddev, r10_bio);
-			unplug = 1;
-		} else 	if (test_bit(R10BIO_IsRecover, &r10_bio->state)) {
+		else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
 			recovery_request_write(mddev, r10_bio);
-			unplug = 1;
-		} else {
+		else {
 			int mirror;
 			/* we got a read error. Maybe the drive is bad.  Maybe just
 			 * the block and we can fix it.
@@ -1759,14 +1711,11 @@ static void raid10d(mddev_t *mddev)
 				bio->bi_rw = READ | do_sync;
 				bio->bi_private = r10_bio;
 				bio->bi_end_io = raid10_end_read_request;
-				unplug = 1;
 				generic_make_request(bio);
 			}
 		}
 		cond_resched();
 	}
-	if (unplug)
-		unplug_slaves(mddev);
 }
 
 
@@ -2377,7 +2326,6 @@ static int run(mddev_t *mddev)
 	md_set_array_sectors(mddev, size);
 	mddev->resync_max_sectors = size;
 
-	mddev->queue->unplug_fn = raid10_unplug;
 	mddev->queue->backing_dev_info.congested_fn = raid10_congested;
 	mddev->queue->backing_dev_info.congested_data = mddev;
 
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 78536fdbd87f..e867ee42b152 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -433,8 +433,6 @@ static int has_failed(raid5_conf_t *conf)
 	return 0;
 }
 
-static void unplug_slaves(mddev_t *mddev);
-
 static struct stripe_head *
 get_active_stripe(raid5_conf_t *conf, sector_t sector,
 		  int previous, int noblock, int noquiesce)
@@ -463,8 +461,7 @@ get_active_stripe(raid5_conf_t *conf, sector_t sector,
 						     < (conf->max_nr_stripes *3/4)
 						     || !conf->inactive_blocked),
 						    conf->device_lock,
-						    md_raid5_unplug_device(conf)
-					);
+						    md_raid5_kick_device(conf));
 				conf->inactive_blocked = 0;
 			} else
 				init_stripe(sh, sector, previous);
@@ -1473,8 +1470,7 @@ 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,
-				    unplug_slaves(conf->mddev)
-			);
+				    blk_flush_plug(current));
 		osh = get_free_stripe(conf);
 		spin_unlock_irq(&conf->device_lock);
 		atomic_set(&nsh->count, 1);
@@ -3645,58 +3641,19 @@ static void activate_bit_delay(raid5_conf_t *conf)
 	}
 }
 
-static void unplug_slaves(mddev_t *mddev)
+void md_raid5_kick_device(raid5_conf_t *conf)
 {
-	raid5_conf_t *conf = mddev->private;
-	int i;
-	int devs = max(conf->raid_disks, conf->previous_raid_disks);
-
-	rcu_read_lock();
-	for (i = 0; i < devs; i++) {
-		mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
-		if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
-			struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
-
-			atomic_inc(&rdev->nr_pending);
-			rcu_read_unlock();
-
-			blk_unplug(r_queue);
-
-			rdev_dec_pending(rdev, mddev);
-			rcu_read_lock();
-		}
-	}
-	rcu_read_unlock();
-}
-
-void md_raid5_unplug_device(raid5_conf_t *conf)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&conf->device_lock, flags);
-
-	if (plugger_remove_plug(&conf->plug)) {
-		conf->seq_flush++;
-		raid5_activate_delayed(conf);
-	}
+	blk_flush_plug(current);
+	raid5_activate_delayed(conf);
 	md_wakeup_thread(conf->mddev->thread);
-
-	spin_unlock_irqrestore(&conf->device_lock, flags);
-
-	unplug_slaves(conf->mddev);
 }
-EXPORT_SYMBOL_GPL(md_raid5_unplug_device);
+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_unplug_device(conf);
-}
 
-static void raid5_unplug_queue(struct request_queue *q)
-{
-	mddev_t *mddev = q->queuedata;
-	md_raid5_unplug_device(mddev->private);
+	md_raid5_kick_device(conf);
 }
 
 int md_raid5_congested(mddev_t *mddev, int bits)
@@ -4100,7 +4057,7 @@ static int make_request(mddev_t *mddev, struct bio * bi)
 				 * add failed due to overlap.  Flush everything
 				 * and wait a while
 				 */
-				md_raid5_unplug_device(conf);
+				md_raid5_kick_device(conf);
 				release_stripe(sh);
 				schedule();
 				goto retry;
@@ -4365,7 +4322,6 @@ static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *ski
 
 	if (sector_nr >= max_sector) {
 		/* just being told to finish up .. nothing much to do */
-		unplug_slaves(mddev);
 
 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
 			end_reshape(conf);
@@ -4569,7 +4525,6 @@ static void raid5d(mddev_t *mddev)
 	spin_unlock_irq(&conf->device_lock);
 
 	async_tx_issue_pending_all();
-	unplug_slaves(mddev);
 
 	pr_debug("--- raid5d inactive\n");
 }
@@ -5204,7 +5159,7 @@ static int run(mddev_t *mddev)
 
 		mddev->queue->backing_dev_info.congested_data = mddev;
 		mddev->queue->backing_dev_info.congested_fn = raid5_congested;
-		mddev->queue->unplug_fn = raid5_unplug_queue;
+		mddev->queue->queue_lock = &conf->device_lock;
 
 		chunk_size = mddev->chunk_sectors << 9;
 		blk_queue_io_min(mddev->queue, chunk_size);
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 2ace0582b409..8d563a4f022a 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -503,6 +503,6 @@ static inline int algorithm_is_DDF(int layout)
 }
 
 extern int md_raid5_congested(mddev_t *mddev, int bits);
-extern void md_raid5_unplug_device(raid5_conf_t *conf);
+extern void md_raid5_kick_device(raid5_conf_t *conf);
 extern int raid5_set_cache_size(mddev_t *mddev, int size);
 #endif