block: avoid setting nr_requests to current value

There's no reason to freeze queue and set nr_requests value
if current value is the same.

Signed-off-by: Aleksei Zakharov <zakharov.a.g@yandex.ru>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 8a825ae..44d471f 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3089,6 +3089,9 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
        if (!set)
                return -EINVAL;
 
+       if (q->nr_requests == nr)
+               return 0;
+
        blk_mq_freeze_queue(q);
        blk_mq_quiesce_queue(q);