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=-5.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,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 00E2FC43465 for ; Mon, 21 Sep 2020 16:04:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A598C216C4 for ; Mon, 21 Sep 2020 16:04:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="E9qxaKsp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727124AbgIUQEO (ORCPT ); Mon, 21 Sep 2020 12:04:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726810AbgIUQEO (ORCPT ); Mon, 21 Sep 2020 12:04:14 -0400 Received: from mail-wm1-x341.google.com (mail-wm1-x341.google.com [IPv6:2a00:1450:4864:20::341]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A1602C061755; Mon, 21 Sep 2020 09:04:13 -0700 (PDT) Received: by mail-wm1-x341.google.com with SMTP id y15so59080wmi.0; Mon, 21 Sep 2020 09:04:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:autocrypt:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=sdIgHQT1sjFsE6Sp3c24zrA/x7Tss24f6B4/9TuIjO0=; b=E9qxaKspPy4ac31AQqZlhWvJ8ossufkaQnqOtY9G9VklJERhT1VY6YqBH20NcXFukY if22BZjssjObVyVnYmfWRGY2OwI2/WHnV2/eY4zZpR1oNKa2aQbEg+quxu2Ak+ZxfYM0 RlV5gjjtBl2RLc6vsXJMKCkvtE6m4cNNtLIM8fkINRkhRaQH0a58K8fQFgNMeKoIFXPT nkQ94emyzpfZEUx4DdOvelpy1wIbhDmJN+TPy1Z7Qf8pNtFdOCRPdUaEHDbanFqcRMES EQmArypqyfhOuAnhZ7hCsjJ4KGhnHkeiX/9Xf9z+SnbFmazWLFO7kJ+ppZEbEBlvqt2h Bs+Q== 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:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=sdIgHQT1sjFsE6Sp3c24zrA/x7Tss24f6B4/9TuIjO0=; b=AcbLMsUy1KU4uQ31lnThcy55HarLRmv6xw+PKXgm0ZjYr5afH7ShZ964/EOKCfO/TQ jDv0jXNJtWtS3RC1aDG7YQQOUgOwS9f5GHadL3XUmipUBmzOvjf25zhBTObWuoK8Aowi oT4nfkH+zCsjFBBCd7XZwmVeOLZwWWgOAgFZHG/A4F76kjaVtX+fDcRYliBVKf1WObsc 88qBrCop3QCxkd1DGAR+gyWUHqP/PHTBltNGW1Gc2KwqUtnNYveOh/t8pb9qFsbI4QQw UNMPGeNDbX/Jpm5IUzNwmQ8aYMjVmeQOFpV7a00DO9kJGdlFWPBJ7fyNyukvH0Z7SM33 wc4g== X-Gm-Message-State: AOAM530GoPqamQPzaHByNeXaYwn/Ro4zV15jjlnKg/DGqGWl8G1rN9Kb N51pBwJfuO+PoolTRJoOENf7vMPf2OI= X-Google-Smtp-Source: ABdhPJwN7HPXY4B4rctAl0JJS0LiMM+FiEhFd89w3+RV1QQUijGyD9FuLnpl0u8obloB9/oPvlHIIQ== X-Received: by 2002:a1c:23c8:: with SMTP id j191mr121403wmj.64.1600704252097; Mon, 21 Sep 2020 09:04:12 -0700 (PDT) Received: from [192.168.43.240] ([5.100.192.97]) by smtp.gmail.com with ESMTPSA id d83sm56754wmf.23.2020.09.21.09.04.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 21 Sep 2020 09:04:11 -0700 (PDT) Subject: Re: [PATCH 4/9 next] fs/io_uring Don't use the return value from import_iovec(). To: David Laight , 'Christoph Hellwig' Cc: "linux-kernel@vger.kernel.org" , "netdev@vger.kernel.org" , "io-uring@vger.kernel.org" , Jens Axboe , "David S. Miller" , Al Viro , linux-fsdevel References: <0dc67994b6b2478caa3d96a9e24d2bfb@AcuMS.aculab.com> <20200921141456.GD24515@infradead.org> <4b204a3e4db74cb2bd8c81e31f6b359b@AcuMS.aculab.com> From: Pavel Begunkov Autocrypt: addr=asml.silence@gmail.com; prefer-encrypt=mutual; keydata= mQINBFmKBOQBEAC76ZFxLAKpDw0bKQ8CEiYJRGn8MHTUhURL02/7n1t0HkKQx2K1fCXClbps bdwSHrhOWdW61pmfMbDYbTj6ZvGRvhoLWfGkzujB2wjNcbNTXIoOzJEGISHaPf6E2IQx1ik9 6uqVkK1OMb7qRvKH0i7HYP4WJzYbEWVyLiAxUj611mC9tgd73oqZ2pLYzGTqF2j6a/obaqha +hXuWTvpDQXqcOZJXIW43atprH03G1tQs7VwR21Q1eq6Yvy2ESLdc38EqCszBfQRMmKy+cfp W3U9Mb1w0L680pXrONcnlDBCN7/sghGeMHjGKfNANjPc+0hzz3rApPxpoE7HC1uRiwC4et83 CKnncH1l7zgeBT9Oa3qEiBlaa1ZCBqrA4dY+z5fWJYjMpwI1SNp37RtF8fKXbKQg+JuUjAa9 Y6oXeyEvDHMyJYMcinl6xCqCBAXPHnHmawkMMgjr3BBRzODmMr+CPVvnYe7BFYfoajzqzq+h EyXSl3aBf0IDPTqSUrhbmjj5OEOYgRW5p+mdYtY1cXeK8copmd+fd/eTkghok5li58AojCba jRjp7zVOLOjDlpxxiKhuFmpV4yWNh5JJaTbwCRSd04sCcDNlJj+TehTr+o1QiORzc2t+N5iJ NbILft19Izdn8U39T5oWiynqa1qCLgbuFtnYx1HlUq/HvAm+kwARAQABtDFQYXZlbCBCZWd1 bmtvdiAoc2lsZW5jZSkgPGFzbWwuc2lsZW5jZUBnbWFpbC5jb20+iQJOBBMBCAA4FiEE+6Ju PTjTbx479o3OWt5b1Glr+6UFAlmKBOQCGwMFCwkIBwIGFQgJCgsCBBYCAwECHgECF4AACgkQ Wt5b1Glr+6WxZA//QueaKHzgdnOikJ7NA/Vq8FmhRlwgtP0+E+w93kL+ZGLzS/cUCIjn2f4Q Mcutj2Neg0CcYPX3b2nJiKr5Vn0rjJ/suiaOa1h1KzyNTOmxnsqE5fmxOf6C6x+NKE18I5Jy xzLQoktbdDVA7JfB1itt6iWSNoOTVcvFyvfe5ggy6FSCcP+m1RlR58XxVLH+qlAvxxOeEr/e aQfUzrs7gqdSd9zQGEZo0jtuBiB7k98t9y0oC9Jz0PJdvaj1NZUgtXG9pEtww3LdeXP/TkFl HBSxVflzeoFaj4UAuy8+uve7ya/ECNCc8kk0VYaEjoVrzJcYdKP583iRhOLlZA6HEmn/+Gh9 4orG67HNiJlbFiW3whxGizWsrtFNLsSP1YrEReYk9j1SoUHHzsu+ZtNfKuHIhK0sU07G1OPN 2rDLlzUWR9Jc22INAkhVHOogOcc5ajMGhgWcBJMLCoi219HlX69LIDu3Y34uIg9QPZIC2jwr 24W0kxmK6avJr7+n4o8m6sOJvhlumSp5TSNhRiKvAHB1I2JB8Q1yZCIPzx+w1ALxuoWiCdwV M/azguU42R17IuBzK0S3hPjXpEi2sK/k4pEPnHVUv9Cu09HCNnd6BRfFGjo8M9kZvw360gC1 reeMdqGjwQ68o9x0R7NBRrtUOh48TDLXCANAg97wjPoy37dQE7e5Ag0EWYoE5AEQAMWS+aBV IJtCjwtfCOV98NamFpDEjBMrCAfLm7wZlmXy5I6o7nzzCxEw06P2rhzp1hIqkaab1kHySU7g dkpjmQ7Jjlrf6KdMP87mC/Hx4+zgVCkTQCKkIxNE76Ff3O9uTvkWCspSh9J0qPYyCaVta2D1 Sq5HZ8WFcap71iVO1f2/FEHKJNz/YTSOS/W7dxJdXl2eoj3gYX2UZNfoaVv8OXKaWslZlgqN jSg9wsTv1K73AnQKt4fFhscN9YFxhtgD/SQuOldE5Ws4UlJoaFX/yCoJL3ky2kC0WFngzwRF Yo6u/KON/o28yyP+alYRMBrN0Dm60FuVSIFafSqXoJTIjSZ6olbEoT0u17Rag8BxnxryMrgR dkccq272MaSS0eOC9K2rtvxzddohRFPcy/8bkX+t2iukTDz75KSTKO+chce62Xxdg62dpkZX xK+HeDCZ7gRNZvAbDETr6XI63hPKi891GeZqvqQVYR8e+V2725w+H1iv3THiB1tx4L2bXZDI DtMKQ5D2RvCHNdPNcZeldEoJwKoA60yg6tuUquvsLvfCwtrmVI2rL2djYxRfGNmFMrUDN1Xq F3xozA91q3iZd9OYi9G+M/OA01husBdcIzj1hu0aL+MGg4Gqk6XwjoSxVd4YT41kTU7Kk+/I 5/Nf+i88ULt6HanBYcY/+Daeo/XFABEBAAGJAjYEGAEIACAWIQT7om49ONNvHjv2jc5a3lvU aWv7pQUCWYoE5AIbDAAKCRBa3lvUaWv7pfmcEACKTRQ28b1y5ztKuLdLr79+T+LwZKHjX++P 4wKjEOECCcB6KCv3hP+J2GCXDOPZvdg/ZYZafqP68Yy8AZqkfa4qPYHmIdpODtRzZSL48kM8 LRzV8Rl7J3ItvzdBRxf4T/Zseu5U6ELiQdCUkPGsJcPIJkgPjO2ROG/ZtYa9DvnShNWPlp+R uPwPccEQPWO/NP4fJl2zwC6byjljZhW5kxYswGMLBwb5cDUZAisIukyAa8Xshdan6C2RZcNs rB3L7vsg/R8UCehxOH0C+NypG2GqjVejNZsc7bgV49EOVltS+GmGyY+moIzxsuLmT93rqyII 5rSbbcTLe6KBYcs24XEoo49Zm9oDA3jYvNpeYD8rDcnNbuZh9kTgBwFN41JHOPv0W2FEEWqe JsCwQdcOQ56rtezdCJUYmRAt3BsfjN3Jn3N6rpodi4Dkdli8HylM5iq4ooeb5VkQ7UZxbCWt UVMKkOCdFhutRmYp0mbv2e87IK4erwNHQRkHUkzbsuym8RVpAZbLzLPIYK/J3RTErL6Z99N2 m3J6pjwSJY/zNwuFPs9zGEnRO4g0BUbwGdbuvDzaq6/3OJLKohr5eLXNU3JkT+3HezydWm3W OPhauth7W0db74Qd49HXK0xe/aPrK+Cp+kU1HRactyNtF8jZQbhMCC8vMGukZtWaAwpjWiiH bA== Message-ID: <47e7d21b-28ae-80d7-8e1a-403f180b0e70@gmail.com> Date: Mon, 21 Sep 2020 19:01:40 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: <4b204a3e4db74cb2bd8c81e31f6b359b@AcuMS.aculab.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 21/09/2020 17:38, David Laight wrote: > From: Christoph Hellwig >> Sent: 21 September 2020 15:15 >> >> On Tue, Sep 15, 2020 at 02:55:20PM +0000, David Laight wrote: >>> >>> This is the only code that relies on import_iovec() returning >>> iter.count on success. >>> This allows a better interface to import_iovec(). Reviewed-by: Pavel Begunkov >> >> This looks generall sane, but a comment below: >> >>> @@ -3123,7 +3123,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock, >>> if (ret < 0) >>> return ret; >>> iov_count = iov_iter_count(iter); >>> - io_size = ret; >>> + io_size = iov_count; >>> req->result = io_size; >>> ret = 0; >>> >>> @@ -3246,7 +3246,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock, >>> if (ret < 0) >>> return ret; >>> iov_count = iov_iter_count(iter); >>> - io_size = ret; >>> + io_size = iov_count; >>> req->result = io_size; >> >> I tink the local iov_count variable can go away in both functions, >> as io_size only changes after the last use of iov_count (io_read) or >> not at all (io_write). Yes, iov_count should be killed, now or later. > > Yes, the compiler will probably make that optimisation. > I did a minimal change because my head hurts whenever I look at io_uring.c. > > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales) > -- Pavel Begunkov