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From: dayou5941@163.com
To: linux-block@vger.kernel.org
Cc: yukuai@fnnas.com, axboe@kernel.dk, liyouhong@kylinos.cn
Subject: [PATCH] block, bfq: skip dispatch when selected queue has no next_rq
Date: Wed, 20 May 2026 17:50:24 +0800	[thread overview]
Message-ID: <20260520095024.685338-1-dayou5941@163.com> (raw)

From: liyouhong <liyouhong@kylinos.cn>

bfq_dispatch_rq_from_bfqq() dispatches bfqq->next_rq directly. Add a
guard in __bfq_dispatch_request() so that dispatch is skipped if the
selected queue unexpectedly has no next request.

This keeps behavior unchanged in normal paths while avoiding entering
the dispatch helper with a missing next_rq.

Signed-off-by: liyouhong <liyouhong@kylinos.cn>

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 141c602d5e85..c3d9d02064b7 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5226,7 +5226,7 @@ static struct request *__bfq_dispatch_request(struct blk_mq_hw_ctx *hctx)
 		goto exit;
 
 	bfqq = bfq_select_queue(bfqd);
-	if (!bfqq)
+	if (!bfqq || !bfqq->next_rq)
 		goto exit;
 
 	rq = bfq_dispatch_rq_from_bfqq(bfqd, bfqq);
-- 
2.25.1


             reply	other threads:[~2026-05-20  9:50 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-20  9:50 dayou5941 [this message]
2026-05-21  9:27 ` [PATCH] block, bfq: skip dispatch when selected queue has no next_rq Yu Kuai
2026-05-21  9:43   ` 李佑鸿 

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