From: Mike Snitzer <snitzer@redhat.com>
Date: Wed, 25 Feb 2015 01:49:18 +0000 (-0500)
Subject: dm: don't schedule delayed run of the queue if nothing to do
X-Git-Tag: firefly_0821_release~176^2~1939^2~21
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=9d1deb83d489364f8749a3a1ba1689efb07d94b0;p=firefly-linux-kernel-4.4.55.git

dm: don't schedule delayed run of the queue if nothing to do

In request-based DM's dm_request_fn(), if blk_peek_request() returns
NULL just return.  Avoids unnecessary blk_delay_queue().

Reported-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 7924c00e0716..6f854287384b 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1963,7 +1963,7 @@ static void dm_request_fn(struct request_queue *q)
 	while (!blk_queue_stopped(q)) {
 		rq = blk_peek_request(q);
 		if (!rq)
-			goto delay_and_out;
+			goto out;
 
 		/* always use block 0 to find the target for flushes for now */
 		pos = 0;