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>
This commit is contained in:
Mike Snitzer 2015-02-24 20:49:18 -05:00
parent 9a0e609e3f
commit 9d1deb83d4

View File

@ -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;