if blk-mq use "none" io scheduler, nr_request get a wrong value when input a number > tag_set->queue_depth. blk_mq_tag_update_depth will get the smaller one min(nr, set->queue_depth), and then q->nr_request get a wrong value.
Reproduce: echo none > /sys/block/nvme0n1/queue/scheduler echo 1000000 > /sys/block/nvme0n1/queue/nr_requests cat /sys/block/nvme0n1/queue/nr_requests 1000000 Signed-off-by: weiping zhang <[email protected]> --- Changes since v4: * fix typo in commit message(queue/ioscheduler => queue/scheduler) Changes since v3: * remove compare nr with tags->qdepth, pass nr to blk_mq_tag_update_depth directly * remove return EINVAL when user modify nr_request less than BLKDEV_MIN_RQ Changes since v2: * add return EINVAL when user modify nr_request less than BLKDEV_MIN_RQ * remove pr_warn, and return EINVAL, if input number is too large block/blk-mq.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 98a1860..491e336 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2642,8 +2642,7 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) * queue depth. This is similar to what the old code would do. */ if (!hctx->sched_tags) { - ret = blk_mq_tag_update_depth(hctx, &hctx->tags, - min(nr, set->queue_depth), + ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr, false); } else { ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags, -- 2.9.4
