From 796a5b1f9c6d057113a98047d4bc446adcc0ab5c Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] blk-mq: Make blk_mq_quiesce_tagset() hold the tag list mutex less long BugLink: https://bugs.launchpad.net/bugs/2101915 commit ccd9e252c515ac5a3ed04a414c95d1307d17f159 upstream. Make sure that the tag_list_lock mutex is not held any longer than necessary. This change reduces latency if e.g. blk_mq_quiesce_tagset() is called concurrently from more than one thread. This function is used by the NVMe core and also by the UFS driver. Reported-by: Peter Wang Cc: Chao Leng Cc: Ming Lei Cc: stable@vger.kernel.org Fixes: 414dd48e882c ("blk-mq: add tagset quiesce interface") Signed-off-by: Bart Van Assche Reviewed-by: Keith Busch Link: https://lore.kernel.org/r/20241022181617.2716173-1-bvanassche@acm.org Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- block/blk-mq.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index fa63d2d78f90..0d9ca9aecb77 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -283,8 +283,9 @@ void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set) if (!blk_queue_skip_tagset_quiesce(q)) blk_mq_quiesce_queue_nowait(q); } - blk_mq_wait_quiesce_done(set); mutex_unlock(&set->tag_list_lock); + + blk_mq_wait_quiesce_done(set); } EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset);