--------
[PATCH] block: blk_execute_rq_nowait(): init rq->end_io before checking for dead queue.

blk-exec.c: In blk_execute_rq_nowait(), if the queue is dead, call to
done() routine is not made. That will result in blk_execute_rq() stuck
in wait_for_completion(). Avoid this by initializing rq->end_io to
done() routine before we check for dead queue.

Signed-off-by: Muthukumar Ratty <muthur@gmail.com>
Tested-by: Bart Van Assche <bvanassche@acm.org>
CC: Tejun Heo <tj@kernel.org>
CC: Jens Axboe <axboe@kernel.dk>
CC: James Bottomley <James.Bottomley@hansenpartnership.com>

--------
diff --git a/block/blk-exec.c b/block/blk-exec.c
index fb2cbd5..00a72da 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -51,6 +51,10 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
 	int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
 
 	WARN_ON(irqs_disabled());
+
+	rq->rq_disk = bd_disk;
+	rq->end_io = done;
+
 	spin_lock_irq(q->queue_lock);
 
 	if (unlikely(blk_queue_dead(q))) {
@@ -61,8 +65,6 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
 		return;
 	}
 
-	rq->rq_disk = bd_disk;
-	rq->end_io = done;
 	__elv_add_request(q, rq, where);
 	__blk_run_queue(q);
 	/* the queue is stopped so it won't be run */