5 files changed, 21 insertions, 12 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index f9a45ebcc7b1..6a488ad2dce5 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -908,6 +908,7 @@ NORET_TYPE void do_exit(long code)
         profile_task_exit(tsk);
 
         WARN_ON(atomic_read(&tsk->fs_excl));
+        WARN_ON(blk_needs_flush_plug(tsk));
 
         if (unlikely(in_interrupt()))
                 panic("Aiee, killing interrupt handler!");
diff --git a/kernel/fork.c b/kernel/fork.c
index 457fff2e17e0..e7548dee636b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1205,6 +1205,9 @@ static struct task_struct *copy_process(unsigned long clone_flags,
          * Clear TID on mm_release()?
          */
         p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
+#ifdef CONFIG_BLOCK
+        p->plug = NULL;
+#endif
 #ifdef CONFIG_FUTEX
         p->robust_list = NULL;
 #ifdef CONFIG_COMPAT
diff --git a/kernel/power/block_io.c b/kernel/power/block_io.c
index 83bbc7c02df9..d09dd10c5a5e 100644
--- a/kernel/power/block_io.c
+++ b/kernel/power/block_io.c
@@ -28,7 +28,7 @@
 static int submit(int rw, struct block_device *bdev, sector_t sector,
                 struct page *page, struct bio **bio_chain)
 {
-        const int bio_rw = rw | REQ_SYNC | REQ_UNPLUG;
+        const int bio_rw = rw | REQ_SYNC;
         struct bio *bio;
 
         bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
diff --git a/kernel/sched.c b/kernel/sched.c
index 480adeb63f8f..ae659b99ce73 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4115,6 +4115,16 @@ need_resched:
                 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))
@@ -5528,6 +5538,7 @@ 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;
@@ -5543,6 +5554,7 @@ 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;
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index cbafed7d4f38..7aa40f8e182d 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -703,28 +703,21 @@ void blk_trace_shutdown(struct request_queue *q)
  *
  **/
 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
-                                    u32 what)
+                             u32 what)
 {
         struct blk_trace *bt = q->blk_trace;
-        int rw = rq->cmd_flags & 0x03;
 
         if (likely(!bt))
                 return;
 
-        if (rq->cmd_flags & REQ_DISCARD)
-                rw |= REQ_DISCARD;
-
-        if (rq->cmd_flags & REQ_SECURE)
-                rw |= REQ_SECURE;
-
         if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
                 what |= BLK_TC_ACT(BLK_TC_PC);
-                __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
+                __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
                                 what, rq->errors, rq->cmd_len, rq->cmd);
         } else  {
                 what |= BLK_TC_ACT(BLK_TC_FS);
-                __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
-                                what, rq->errors, 0, NULL);
+                __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
+                                rq->cmd_flags, what, rq->errors, 0, NULL);
         }
 }