From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A138C4332F for ; Thu, 8 Dec 2022 16:48:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229955AbiLHQs2 (ORCPT ); Thu, 8 Dec 2022 11:48:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54584 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229724AbiLHQs1 (ORCPT ); Thu, 8 Dec 2022 11:48:27 -0500 Received: from mail-il1-x12b.google.com (mail-il1-x12b.google.com [IPv6:2607:f8b0:4864:20::12b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 337FD419B0 for ; Thu, 8 Dec 2022 08:48:26 -0800 (PST) Received: by mail-il1-x12b.google.com with SMTP id h17so1307006ila.6 for ; Thu, 08 Dec 2022 08:48:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=GtTytaGK8EscfaX5sQg3WzTsPcFXdf66H/Qr7gq+ZeU=; b=1NsVi2LPvryDN0YAtJX6LCnADQ5OzXCjCNF5Oupz+xOmf6Z5HVHcfdWy5625BkIexO UPLI6mwR3tRA0ncoREpcYqAmWRjcQO++s0NBr4mWPc8q07+1woGt+JkoS1J4koa/m34i 0uqh9nyJx6KJSXY6iDolAOLSwXgGMoCDTblFvkDBS2H21bc+5TZR9++P+qymHP87IdDt i7mJQ0460G0eqY73I96vwKFYE/SxEdk0GsPXjmjpWsjHfHrlC7okE6rvKSRH8b11sXFc xVlDw3S4/ZN0X0BptZoILKvSU0kOzZILD05dplubtfBlkbI340vbh9dQoUMNPKAYX6Eb z4sg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=GtTytaGK8EscfaX5sQg3WzTsPcFXdf66H/Qr7gq+ZeU=; b=LEFZhGOsgKKn9vKK/2hPLWBs3E89piV5Z5wC4ZRZkCi6kIVsgZYtLkAnPAlIUrG80t sHVZ/OImGgnxY/hXZrh3+LA86EjZhNU8D6fmer+kAswBYPbGIaiuP2qJ4wwjZuUkpK5J 3V3zmK9bMlTQnREg2A++hsV4wtm324xW3MPG03WAuLGtGjIgb++aGZFqU00PA7xVVU39 2BbP55lS0FSTd0FgcNqVtpL7clOsxB7K5cGnkjm5mHgTmY9ntkZ6gyJSkGNWeIPxTus/ v8we2V8h86ZchjnWlfjTmn/D4rCTCSeGwK3y8NaSd5FLVPzZuylG244T+eJHoDOP9S5V iX0g== X-Gm-Message-State: ANoB5pm4qA5VER77pqH/TiT0fkfvOKp3jPPTZ5lCqCI1l7/mDBnbAqzY smDpzfkOUbGbAj4Naes/OkVjlg== X-Google-Smtp-Source: AA0mqf4Zzqp5ZuBvsh/zTJ1XExTv5sm3H2YTh8G90igsKIvVAiQzO0XoCxhbm7fpoFjKEzpIO4+lgQ== X-Received: by 2002:a6b:8f84:0:b0:6e0:2427:f72e with SMTP id r126-20020a6b8f84000000b006e02427f72emr5170180iod.55.1670518105458; Thu, 08 Dec 2022 08:48:25 -0800 (PST) Received: from [192.168.1.94] ([207.135.234.126]) by smtp.gmail.com with ESMTPSA id n11-20020a056638110b00b00389d74d7e24sm8752485jal.146.2022.12.08.08.48.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 08 Dec 2022 08:48:25 -0800 (PST) Message-ID: <4701aded-0464-791e-8b8c-a34c422e8e62@kernel.dk> Date: Thu, 8 Dec 2022 09:48:23 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.5.1 Subject: Re: [PATCH 1/2] virtio-blk: set req->state to MQ_RQ_COMPLETE after polling I/O is finished Content-Language: en-US To: Stefan Hajnoczi Cc: mst@redhat.com, jasowang@redhat.com, pbonzini@redhat.com, hch@infradead.org, virtualization@lists.linux-foundation.org, linux-block@vger.kernel.org, Suwan Kim References: <20221206141125.93055-1-suwan.kim027@gmail.com> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 12/7/22 2:47 PM, Stefan Hajnoczi wrote: > On Tue, Dec 06, 2022 at 11:11:24PM +0900, Suwan Kim wrote: >> Driver should set req->state to MQ_RQ_COMPLETE after it finishes to process >> req. But virtio-blk doesn't set MQ_RQ_COMPLETE after virtblk_poll() handles >> req and req->state still remains MQ_RQ_IN_FLIGHT. Fortunately so far there >> is no issue about it because blk_mq_end_request_batch() sets req->state to >> MQ_RQ_IDLE. This patch properly sets req->state after polling I/O is finished. >> >> Fixes: 4e0400525691 ("virtio-blk: support polling I/O") >> Signed-off-by: Suwan Kim >> --- >> drivers/block/virtio_blk.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c >> index 19da5defd734..cf64d256787e 100644 >> --- a/drivers/block/virtio_blk.c >> +++ b/drivers/block/virtio_blk.c >> @@ -839,6 +839,7 @@ static void virtblk_complete_batch(struct io_comp_batch *iob) >> rq_list_for_each(&iob->req_list, req) { >> virtblk_unmap_data(req, blk_mq_rq_to_pdu(req)); >> virtblk_cleanup_cmd(req); >> + blk_mq_set_request_complete(req); >> } >> blk_mq_end_request_batch(iob); >> } > > The doc comment for blk_mq_set_request_complete() mentions this being > used in ->queue_rq(), but that's not the case here. Does the doc comment > need to be updated if we're using the function in a different way? Looks like it's a bit outdated... > I'm not familiar enough with the Linux block APIs, but this feels weird > to me. Shouldn't blk_mq_end_request_batch(iob) take care of this for us? > Why does it set the state to IDLE instead of COMPLETE? > > I think Jens can confirm whether we really want all drivers that use > polling and io_comp_batch to manually call > blk_mq_set_request_complete(). Should not be a need to call blk_mq_set_request_complete() directly in the driver for this. -- Jens Axboe