From patchwork Sat Sep 14 07:28:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muchun Song X-Patchwork-Id: 13804300 Received: from mail-pf1-f175.google.com (mail-pf1-f175.google.com [209.85.210.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F274A146D57 for ; Sat, 14 Sep 2024 07:30:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.175 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726299057; cv=none; b=K8J0g9xm9vilVcG7jL7f++uWQH91/XgFwxZzSgF48NNGTC6D76g+It7bvCzAoRN8f2qkaaP8YupyYRV91msw1+f5/Nx5C1DCCEydbCqV01klTOHJv2FzY0ocZV9iaK2UV3BN33X/r5m6BtndgedbxaMcINdC6w3R1BYrik5dNDs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726299057; c=relaxed/simple; bh=NfYRJbO+n9KlpHo78YK1kJWVU0JEHSyMKcCC/4kPv2g=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=NZULghLnmd58vFW5UMSrEsmZqKEU5rlRom8YflXEtoPh/yLIy2bTQf66AHBM2Tvow9TTn6Tg6jn0kN1Aaji3RJMHLCS8k3x/WBPe2GbShou/e0XAc0rTSHNiGFN9FV+5Z17ajklO6GQRy8yZrqoHMmvmWNUs8vzX+KTaJlFEfCs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com; spf=pass smtp.mailfrom=bytedance.com; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b=PB4Qvvdw; arc=none smtp.client-ip=209.85.210.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bytedance.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b="PB4Qvvdw" Received: by mail-pf1-f175.google.com with SMTP id d2e1a72fcca58-718e1ce7e84so2130289b3a.1 for ; Sat, 14 Sep 2024 00:30:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1726299055; x=1726903855; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=mqOMUsIf1mnLDxR4ticuxNbonVeXyKT1mpHNVeoepzQ=; b=PB4Qvvdwm51+gOBZprDFm8tkkOYMvdxGtcu/a3L47vXsT/g3hHUPcJEYLh+ZmSEWWJ XTqy1V/u4qeNrXYw3q6/HOxsOROKvgnNhAPV8pCPcjVRnQ7PEYmW18RnfDSKt8uYRcjr Iv0l+yRu9jLmkSRGFAClJHMShW/H6ncFlO8+NgDFbAas+6HyWk12oYDdVkaPiHX4dFNk bA/gtBFo0HkLbvLl208uiYIM/wpnSYoC9CghPGAsZkWz5BmylCEo8Wh4wtJohOT1TJvy VOGzSSkYfZOId6C3JaF5spIk10XNg+FhiXKAMH1fhJoyDT2kdh3jDvKFzVkG+MltYMeC r4tw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1726299055; x=1726903855; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=mqOMUsIf1mnLDxR4ticuxNbonVeXyKT1mpHNVeoepzQ=; b=NfBpCQ/Rksqhb4drYUhI6mpc188x2npbWNe/tld8nqXu9lsfiP/P4ZZRbKFNwdGxjj ip089U8ATIZi86IMmg+7TX/slOwREgnYpU8+hBpqf+nieedBOXHvxW4BV072DXtBCuNO FEGlzbCrBiYZNvm/26Z1e7hdJzDXRdvqm1J8NkFrSoniHbXXBJQNHeOpLrqZfE3AB5n0 o/eNCp879DH8f1pLabMKNkuHCzW91deWMcj2V1pPwFyo3R0C6TBvPhhSMbf92Z34dMME WIuyd08WdsA6HEK/0G5ySSoFBH+aWvcPEbPksZoi4XMahKWX4PkSwJFnMXB/SCBr9NzE eYRw== X-Gm-Message-State: AOJu0YwDsA/oOAp2Cj6SrZAOwrqemmdrI5d+11HVCUlF7f+c+0gCTq1i BxJzHxm3Bq7gPIqriw7R5kS7Po19GRoJCuq29b9kIkjm0zHTRb4hrXDG1RDNvsg= X-Google-Smtp-Source: AGHT+IHDTQbRO6cV5Mbr0x+fq++p+seJtKKFdtV1cqhsFN5NWwbtCCv5rOqEpU4gF1AdgNhIZhWkdQ== X-Received: by 2002:a05:6a00:993:b0:714:157a:bfc7 with SMTP id d2e1a72fcca58-71926084bb4mr13041594b3a.15.1726299055036; Sat, 14 Sep 2024 00:30:55 -0700 (PDT) Received: from PXLDJ45XCM.bytedance.net ([61.213.176.6]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-71944b9ac05sm555687b3a.155.2024.09.14.00.30.51 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sat, 14 Sep 2024 00:30:54 -0700 (PDT) From: Muchun Song To: axboe@kernel.dk, ming.lei@redhat.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, muchun.song@linux.dev, Muchun Song , stable@vger.kernel.org Subject: [PATCH v3 1/3] block: fix missing dispatching request when queue is started or unquiesced Date: Sat, 14 Sep 2024 15:28:42 +0800 Message-Id: <20240914072844.18150-2-songmuchun@bytedance.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20240914072844.18150-1-songmuchun@bytedance.com> References: <20240914072844.18150-1-songmuchun@bytedance.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Supposing the following scenario with a virtio_blk driver. CPU0 CPU1 CPU2 blk_mq_try_issue_directly() __blk_mq_issue_directly() q->mq_ops->queue_rq() virtio_queue_rq() blk_mq_stop_hw_queue() virtblk_done() blk_mq_try_issue_directly() if (blk_mq_hctx_stopped()) blk_mq_request_bypass_insert() blk_mq_run_hw_queue() blk_mq_run_hw_queue() blk_mq_run_hw_queue() blk_mq_insert_request() return After CPU0 has marked the queue as stopped, CPU1 will see the queue is stopped. But before CPU1 puts the request on the dispatch list, CPU2 receives the interrupt of completion of request, so it will run the hardware queue and marks the queue as non-stopped. Meanwhile, CPU1 also runs the same hardware queue. After both CPU1 and CPU2 complete blk_mq_run_hw_queue(), CPU1 just puts the request to the same hardware queue and returns. It misses dispatching a request. Fix it by running the hardware queue explicitly. And blk_mq_request_issue_directly() should handle a similar situation. Fix it as well. Fixes: d964f04a8fde ("blk-mq: fix direct issue") Cc: stable@vger.kernel.org Cc: Muchun Song Signed-off-by: Muchun Song Reviewed-by: Ming Lei --- block/blk-mq.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/blk-mq.c b/block/blk-mq.c index e3c3c0c21b553..b2d0f22de0c7f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2619,6 +2619,7 @@ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) { blk_mq_insert_request(rq, 0); + blk_mq_run_hw_queue(hctx, false); return; } @@ -2649,6 +2650,7 @@ static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last) if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) { blk_mq_insert_request(rq, 0); + blk_mq_run_hw_queue(hctx, false); return BLK_STS_OK; }