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>

1 files changed, 12 insertions, 0 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 18d38e4ec7b..ca098bf4cc6 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3978,6 +3978,16 @@ need_resched_nonpreemptible:
 		switch_count = &prev->nvcsw;
 	}
 
+	/*
+	 * If we are going to sleep and we have plugged IO queued, make
+	 * sure to submit it to avoid deadlocks.
+	 */
+	if (prev->state != TASK_RUNNING && blk_needs_flush_plug(prev)) {
+		raw_spin_unlock(&rq->lock);
+		blk_flush_plug(prev);
+		raw_spin_lock(&rq->lock);
+	}
+
 	pre_schedule(rq, prev);
 
 	if (unlikely(!rq->nr_running))
@@ -5333,6 +5343,7 @@ void __sched io_schedule(void)
 
 	delayacct_blkio_start();
 	atomic_inc(&rq->nr_iowait);
+	blk_flush_plug(current);
 	current->in_iowait = 1;
 	schedule();
 	current->in_iowait = 0;
@@ -5348,6 +5359,7 @@ long __sched io_schedule_timeout(long timeout)
 
 	delayacct_blkio_start();
 	atomic_inc(&rq->nr_iowait);
+	blk_flush_plug(current);
 	current->in_iowait = 1;
 	ret = schedule_timeout(timeout);
 	current->in_iowait = 0;