blk-mq: make driver tag failure path easier to follow

Minor cleanup that makes it easier to figure out what's going on in the
driver tag allocation failure path of blk_mq_dispatch_rq_list().

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Omar Sandoval 2017-04-05 12:01:35 -07:00 committed by Jens Axboe
parent ee056f9812
commit 807b10417b

View File

@ -1003,17 +1003,16 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list)
* The initial allocation attempt failed, so we need to
* rerun the hardware queue when a tag is freed.
*/
if (blk_mq_dispatch_wait_add(hctx)) {
/*
* It's possible that a tag was freed in the
* window between the allocation failure and
* adding the hardware queue to the wait queue.
*/
if (!blk_mq_get_driver_tag(rq, &hctx, false))
break;
} else {
if (!blk_mq_dispatch_wait_add(hctx))
break;
/*
* It's possible that a tag was freed in the window
* between the allocation failure and adding the
* hardware queue to the wait queue.
*/
if (!blk_mq_get_driver_tag(rq, &hctx, false))
break;
}
}
list_del_init(&rq->queuelist);