linux-kernel - [PATCH 03/16] blk-mq: remove useless checkings from blk_mq_update_nr

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Message-Id: <20250814033522.770575-4-yukuai1@huaweicloud.com>
Date: Thu, 14 Aug 2025 11:35:09 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: axboe@...nel.dk,
	yukuai3@...wei.com,
	bvanassche@....org,
	nilay@...ux.ibm.com,
	hare@...e.de,
	ming.lei@...hat.com
Cc: linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	yukuai1@...weicloud.com,
	yi.zhang@...wei.com,
	yangerkun@...wei.com,
	johnny.chenyi@...wei.com
Subject: [PATCH 03/16] blk-mq: remove useless checkings from blk_mq_update_nr_requests()

From: Yu Kuai <yukuai3@...wei.com>

1) queue_requests_store() is the only caller of
blk_mq_update_nr_requests(), where queue is already freezed, no need to
check mq_freeze_depth;
2) q->tag_set must be set for request_based device, and queue_is_mq() is
already checked in blk_mq_queue_attr_visible(), no need to check
q->tag_set.
3) During initialization, hctx->tags in initialized before queue
kobject, and during del_gendisk, queue kobject is deleted before
exiting hctx, hence checking hctx->tags is useless.

Signed-off-by: Yu Kuai <yukuai3@...wei.com>
---
 block/blk-mq.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index b67d6c02eceb..3a219b7b3688 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4921,24 +4921,15 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
 {
 	struct blk_mq_tag_set *set = q->tag_set;
 	struct blk_mq_hw_ctx *hctx;
-	int ret;
+	int ret = 0;
 	unsigned long i;
 
-	if (WARN_ON_ONCE(!q->mq_freeze_depth))
-		return -EINVAL;
-
-	if (!set)
-		return -EINVAL;
-
 	if (q->nr_requests == nr)
 		return 0;
 
 	blk_mq_quiesce_queue(q);
 
-	ret = 0;
 	queue_for_each_hw_ctx(q, hctx, i) {
-		if (!hctx->tags)
-			continue;
 		/*
 		 * If we're using an MQ scheduler, just update the scheduler
 		 * queue depth. This is similar to what the old code would do.
-- 
2.39.2