[PATCH 2/8] blk-mq: skip non-mq queues in blk_mq_quiesce_queue

[Hannes Reinecke]

On 10/20/22 12:56, Christoph Hellwig wrote:
> For submit_bio based queues there is no (S)RCU critical section during
> I/O submission and thus nothing to wait for in blk_mq_wait_quiesce_done,
> so skip doing any synchronization.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> ---
>   block/blk-mq.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 33292c01875d5..df967c8af9fee 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -280,7 +280,9 @@ EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done);
>   void blk_mq_quiesce_queue(struct request_queue *q)
>   {
>   	blk_mq_quiesce_queue_nowait(q);
> -	blk_mq_wait_quiesce_done(q);
> +	/* nothing to wait for non-mq queues */
> +	if (queue_is_mq(q))
> +		blk_mq_wait_quiesce_done(q);
>   }
>   EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
>   
Reviewed-by: Hannes Reinecke <hare at suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
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