[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20220621205041.250426-16-sashal@kernel.org>
Date: Tue, 21 Jun 2022 16:50:39 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Ming Lei <ming.lei@...hat.com>, Christoph Hellwig <hch@....de>,
Yu Kuai <yukuai3@...wei.com>, Jens Axboe <axboe@...nel.dk>,
Sasha Levin <sashal@...nel.org>, linux-block@...r.kernel.org
Subject: [PATCH AUTOSEL 5.15 16/17] blk-mq: don't clear flush_rq from tags->rqs[]
From: Ming Lei <ming.lei@...hat.com>
[ Upstream commit 6cfeadbff3f8905f2854735ebb88e581402c16c4 ]
commit 364b61818f65 ("blk-mq: clearing flush request reference in
tags->rqs[]") is added to clear the to-be-free flush request from
tags->rqs[] for avoiding use-after-free on the flush rq.
Yu Kuai reported that blk_mq_clear_flush_rq_mapping() slows down boot time
by ~8s because running scsi probe which may create and remove lots of
unpresent LUNs on megaraid-sas which uses BLK_MQ_F_TAG_HCTX_SHARED and
each request queue has lots of hw queues.
Improve the situation by not running blk_mq_clear_flush_rq_mapping if
disk isn't added when there can't be any flush request issued.
Reviewed-by: Christoph Hellwig <hch@....de>
Reported-by: Yu Kuai <yukuai3@...wei.com>
Signed-off-by: Ming Lei <ming.lei@...hat.com>
Link: https://lore.kernel.org/r/20220616014401.817001-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
block/blk-mq.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 95da44063e65..cc313b364691 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2681,8 +2681,9 @@ static void blk_mq_exit_hctx(struct request_queue *q,
if (blk_mq_hw_queue_mapped(hctx))
blk_mq_tag_idle(hctx);
- blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx],
- set->queue_depth, flush_rq);
+ if (blk_queue_init_done(q))
+ blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx],
+ set->queue_depth, flush_rq);
if (set->ops->exit_request)
set->ops->exit_request(set, flush_rq, hctx_idx);
--
2.35.1
Powered by blists - more mailing lists