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From: Omar Sandoval <osandov@osandov.com>
To: Jens Axboe <axboe@fb.com>, linux-block@vger.kernel.org
Cc: kernel-team@fb.com
Subject: [PATCH v3 7/8] blk-mq: make driver tag failure path easier to follow
Date: Wed,  5 Apr 2017 12:01:35 -0700	[thread overview]
Message-ID: <41f30269ef99fc7825e6a4ddc41bf0b642e5de98.1491418411.git.osandov@fb.com> (raw)
In-Reply-To: <cover.1491418411.git.osandov@fb.com>
In-Reply-To: <cover.1491418411.git.osandov@fb.com>

From: Omar Sandoval <osandov@fb.com>

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>
---
 block/blk-mq.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 39e9af3498ac..de57e7727c52 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -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);
-- 
2.12.2

  parent reply	other threads:[~2017-04-05 19:02 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-05 19:01 [PATCH v3 0/8] blk-mq: various fixes and cleanups Omar Sandoval
2017-04-05 19:01 ` [PATCH v3 1/8] blk-mq: use the right hctx when getting a driver tag fails Omar Sandoval
2017-04-06  4:31   ` Ming Lei
2017-04-06  7:57     ` Omar Sandoval
2017-04-06  8:23       ` Ming Lei
2017-04-06 19:29         ` Jens Axboe
2017-04-07  3:23           ` Ming Lei
2017-04-07 14:45             ` Jens Axboe
2017-04-11  2:12               ` Ming Lei
2017-04-11  2:15                 ` Ming Lei
2017-04-05 19:01 ` [PATCH v3 2/8] blk-mq-sched: refactor scheduler initialization Omar Sandoval
2017-04-05 19:01 ` [PATCH v3 3/8] blk-mq-sched: set up scheduler tags when bringing up new queues Omar Sandoval
2017-04-05 19:01 ` [PATCH v3 4/8] blk-mq-sched: fix crash in switch error path Omar Sandoval
2017-04-05 19:01 ` [PATCH v3 5/8] blk-mq: remap queues when adding/removing hardware queues Omar Sandoval
2017-04-05 19:01 ` [PATCH v3 6/8] blk-mq-sched: provide hooks for initializing hardware queue data Omar Sandoval
2017-04-05 19:01 ` Omar Sandoval [this message]
2017-04-05 19:01 ` [PATCH v3 8/8] blk-mq: use true instead of 1 for blk_mq_queue_data.last Omar Sandoval

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