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From:   Jinlong Chen <nickyc975@zju.edu.cn>
To:     axboe@kernel.dk, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-nvme@lists.infradead.org, nickyc975@zju.edu.cn
Subject: [PATCH v2 1/3] blk-mq: remove redundant call to blk_freeze_queue_start in blk_mq_destroy_queue
Date:   Sun, 30 Oct 2022 11:06:46 +0800
Message-Id: <3a6d54a5adc8bd09aab28abfbe5f5b02bb863a8d.1667098953.git.nickyc975@zju.edu.cn>
In-Reply-To: <cover.1667098953.git.nickyc975@zju.edu.cn>
References: <cover.1667098953.git.nickyc975@zju.edu.cn>
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The calling relationship in blk_mq_destroy_queue() is as follows:

blk_mq_destroy_queue()
    ...
    -> blk_queue_start_drain()
        -> blk_freeze_queue_start()  <- called
        ...
    -> blk_freeze_queue()
        -> blk_freeze_queue_start()  <- called again
        -> blk_mq_freeze_queue_wait()

So there is a redundant call to blk_freeze_queue_start(). Replace
blk_freeze_queue() with blk_mq_freeze_queue_wait() to avoid the redundant
call.

Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
---
 block/blk-mq.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4cecf281123f..14c4165511b9 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4005,7 +4005,12 @@ void blk_mq_destroy_queue(struct request_queue *q)
 
 	blk_queue_flag_set(QUEUE_FLAG_DYING, q);
 	blk_queue_start_drain(q);
-	blk_freeze_queue(q);
+
+	/*
+	 * blk_freeze_queue_start has been called in blk_queue_start_drain, we just
+	 * need to wait.
+	 */
+	blk_mq_freeze_queue_wait(q);
 
 	blk_sync_queue(q);
 	blk_mq_cancel_work_sync(q);
-- 
2.31.1