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 X-Spam-Level: X-Spam-Status: No, score=-1.2 required=3.0 tests=DATE_IN_PAST_03_06, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 542B0C432C0 for ; Thu, 21 Nov 2019 02:33:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 25679206A4 for ; Thu, 21 Nov 2019 02:33:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="c63cxChE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725904AbfKUCdx (ORCPT ); Wed, 20 Nov 2019 21:33:53 -0500 Received: from mail-pj1-f65.google.com ([209.85.216.65]:44003 "EHLO mail-pj1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725842AbfKUCdx (ORCPT ); Wed, 20 Nov 2019 21:33:53 -0500 Received: by mail-pj1-f65.google.com with SMTP id a10so732473pju.10 for ; Wed, 20 Nov 2019 18:33:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=eq2OcbSgFU50j5+5pu07awk+kHx4eS64+TjWrpLwom8=; b=c63cxChEzOlsV62kkVVl40tSKw9iOU/Xr8VQv/r7e31I5iiukRjUvH3hh+A9p0xHPi ES3BXZXkue7KeVAy+xqpOqcaanAeN9SmnzKlxciM1rJVOZ3w1/YWVt+XQZG7Sh5Jgh+9 QMoKPo70j3v2KBmRtZqC/1hx4B+ca3n3F4lMmYwoTSs7E+0HwLh7sRlEzE+/mXvGvWX+ 7pSAUxtbl04pVwpFmb813QkliFYsNi1D6lmPAHy/+YjaIR/oaPSQN0ga8I50wucapRRD MuNoj2QwLpyySor/PHenf1D5Je4n+C+XPyEUiE4nOf4U+n4NYzhA487pH+YD0KO+VcsR fuyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=eq2OcbSgFU50j5+5pu07awk+kHx4eS64+TjWrpLwom8=; b=TDju2q9C5IZdpZFpu127xhckk+8QhkHCNBmVNuoWIAVokMG6KeNfwGPUy15gmENwi/ zsbsG8JOpgBoMMGC/0fv+ecznUL4gbnm333obvqXMmns+Q6JfoA8HsLQAM9aYoIgqFC/ B3Mazl5WOJ53xx12edx6p5qC55tKJLzmoZMuCfaGXSwFHhPiNP5PEsMuFheRu4eBd7eO moj6vE3JXLy77ysES4mneNGvUpdK+NIBa/d3vSfxjQsrWxQOaGCe7lY0ABwVz11zQmXH DEwVkU9Yr9mdCJkcEUAfefyyuOlN1ONW2T2DEDMDq3eXgtCXJ5hcuFt1q8OqQQHi2uu5 spsg== X-Gm-Message-State: APjAAAVv9ZigFqjXGc6BJMFVaoOH38L3R6VoJKYp6hchwPWvj5ZlZtV8 uo0v01FDPdDkLC75QlxV0W+B+AHyZZJnGw== X-Google-Smtp-Source: APXvYqxz4Gl6th38wDMUO9eT3S7/MUavYJQRvgn7EBLFCb+FeoEmBflrN7Ak3Wev2osqcfoAsgHd8w== X-Received: by 2002:aa7:9a96:: with SMTP id w22mr8031869pfi.162.1574302201629; Wed, 20 Nov 2019 18:10:01 -0800 (PST) Received: from [192.168.1.188] ([66.219.217.79]) by smtp.gmail.com with ESMTPSA id e17sm517045pgt.89.2019.11.20.18.10.00 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Nov 2019 18:10:00 -0800 (PST) Subject: Re: [PATCH] io_uring: fix race with shadow drain deferrals To: Jackie Liu Cc: io-uring@vger.kernel.org References: <27c153ee-cfc8-3251-a874-df85a033429a@kernel.dk> <1C6D35BF-C89B-4AB9-83CD-0A6B676E4752@kylinos.cn> <890E4F5B-DDA2-40EF-B7AD-3C63EFA20D93@kylinos.cn> <2005c339-5ed3-6c2e-f011-5bc89dac3f5c@kernel.dk> <7ae652ee-0274-b8c6-9597-9dd82f939d9b@kernel.dk> <57EF3B0C-A6D3-45D5-A689-B8090F750C1E@kylinos.cn> From: Jens Axboe Message-ID: Date: Wed, 20 Nov 2019 16:03:04 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <57EF3B0C-A6D3-45D5-A689-B8090F750C1E@kylinos.cn> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 11/20/19 7:07 PM, Jackie Liu wrote: > > >> 2019年11月21日 07:14，Jens Axboe 写道： >> >> On 11/20/19 6:57 PM, Jackie Liu wrote: >>>> @@ -2957,15 +2975,14 @@ static void io_queue_sqe(struct io_kiocb *req) >>>> int ret; >>>> >>>> ret = io_req_defer(req); >>>> - if (ret) { >>>> - if (ret != -EIOCBQUEUED) { >>>> - io_cqring_add_event(req, ret); >>>> - if (req->flags & REQ_F_LINK) >>>> - req->flags |= REQ_F_FAIL_LINK; >>>> - io_double_put_req(req); >>>> - } >>>> - } else >>>> + if (!ret) { >>>> __io_queue_sqe(req); >>>> + } else if (ret != -EIOCBQUEUED) { >>>> + io_cqring_add_event(req, ret); >>>> + if (req->flags & REQ_F_LINK) >>>> + req->flags |= REQ_F_FAIL_LINK; >>>> + io_double_put_req(req); >>>> + } >>>> } >>> >>> Hmm.. Why we need rewrite there? clear code? Seems to be unrelated to >>> this issue. >> >> We don't need to, and the previous patch touched it, but it's much >> easier to read after this change. Before it was: >> >> if (ret) { >> if (ret != -EIOCBQUEUED) { >> ... >> } >> } else { >> ... >> } >> >> which is now just >> >> if (!ret) { >> ... >> } else if (ret != -EIOCBQUEUED) { >> ... >> } >> >> not related to the change really, but kind of silly to make a separate >> patch for imho. >> > > Understand, thanks for explaining and fixing this problem, > And now, please add: > > Reviewed-by: Jackie Liu Thanks for reviewing it, I've added your reviewed-by. -- Jens Axboe