From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C0DF78F70 for ; Sun, 16 Jul 2023 19:56:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48CF6C433C9; Sun, 16 Jul 2023 19:56:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689537414; bh=MtxnVlsEN6GGFF26TPDSYZHWhUBTVm/57MZO07suUVI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=v2j031PIGUCN8dQs7JAh3eksRcwPfaMYvHRab6qksq21Fhw4YkU4TH7YgreXScNSW R2gadeH7jLis5SpLM1u3Y2AEgqBzep9ZYpGb8CwTZBUBjfHUCnGUjMSbvH8ENmi7Ee BfdCTRRQjj9IvvwiKnVL+6L7JUmruo5haASlmjcQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Guangwu Zhang , Ming Lei , Jens Axboe , Sasha Levin Subject: [PATCH 6.4 060/800] blk-mq: dont insert passthrough request into sw queue Date: Sun, 16 Jul 2023 21:38:33 +0200 Message-ID: <20230716194950.481685843@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230716194949.099592437@linuxfoundation.org> References: <20230716194949.099592437@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ming Lei [ Upstream commit 2293cae703cda162684ae966db6b1b4a11b5e88f ] In case of real io scheduler, q->elevator is set, so blk_mq_run_hw_queue() may just check if scheduler queue has request to dispatch, see __blk_mq_sched_dispatch_requests(). Then IO hang may be caused because all passthorugh requests may stay in sw queue. And any passthrough request should have been inserted to hctx->dispatch always. Reported-by: Guangwu Zhang Fixes: d97217e7f024 ("blk-mq: don't queue plugged passthrough requests into scheduler") Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20230621132208.1142318-1-ming.lei@redhat.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-mq.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index c763f0bc66371..b9f4546139894 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2735,7 +2735,12 @@ static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched) percpu_ref_get(&this_hctx->queue->q_usage_counter); /* passthrough requests should never be issued to the I/O scheduler */ - if (this_hctx->queue->elevator && !is_passthrough) { + if (is_passthrough) { + spin_lock(&this_hctx->lock); + list_splice_tail_init(&list, &this_hctx->dispatch); + spin_unlock(&this_hctx->lock); + blk_mq_run_hw_queue(this_hctx, from_sched); + } else if (this_hctx->queue->elevator) { this_hctx->queue->elevator->type->ops.insert_requests(this_hctx, &list, 0); blk_mq_run_hw_queue(this_hctx, from_sched); -- 2.39.2