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=-14.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 C02EEC433E0 for ; Sat, 16 Jan 2021 18:34:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83CEC227C3 for ; Sat, 16 Jan 2021 18:34:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726608AbhAPSe2 (ORCPT ); Sat, 16 Jan 2021 13:34:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725964AbhAPSe1 (ORCPT ); Sat, 16 Jan 2021 13:34:27 -0500 Received: from mail-wm1-x332.google.com (mail-wm1-x332.google.com [IPv6:2a00:1450:4864:20::332]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 57614C061573 for ; Sat, 16 Jan 2021 10:33:47 -0800 (PST) Received: by mail-wm1-x332.google.com with SMTP id h17so9912183wmq.1 for ; Sat, 16 Jan 2021 10:33:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:autocrypt:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=BG6mFVgbia+Yvuhl4qv4pda1nLFncVy/hgcCFwy71sE=; b=VT5hmRF3Wx1zN6BQ91uLkmJfP7sjvYuKMmnQR5VwPFdRoGcRgqVxS5BA01lrDhOYll KD+JpcG/+ATR/ootgwTM2Qwz6PFWqacmgEoj3XswTc8vC4ZVrDzCCwLUn/27X1YwYEAe EB+OX5dQDufsmXuePMtTtA5+vUz0NvBh8HSxCaQAQKd2wlFpPl1rbZxU4UhUNno+3K6s gCEIOR7SzfAyHg8ylBUJYhhVIasxAHlDToatMrE21LgFlxfsMLbp8bCqmNO0BNLpocFu mjITLRtZuEJTrLCFwVfvkrVSQNn+v3Eh7yIgcCXmO+zLS9zOVcU2LEiWu3vxYk9dXXEw TxnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:autocrypt:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=BG6mFVgbia+Yvuhl4qv4pda1nLFncVy/hgcCFwy71sE=; b=Ocgrb1XBK2sKUM1sGUY5AjGFo3puYxYgpBPBnQoli11wwFIujkn3xbYgnCXhVTImB3 4hBmq0Hq78sfLHo4RHF0P/7owZhwZiQH3S8DZgqp1B5HSyY39ioSvYjj1XQyQnopz7Cx KjfkxnizaULElvTZ+/SMX4jviqPlpU+spRZWFFTOYj2xVEaUZzsleN5Ks9kDc5MT+10Y qLef5z9qThTSTsivoR8opgMs/AxQuD+RRZMzMXtZJ3D5P4sZdYTZ9liHxmpxiD847Aig FDrfgFl4KmxBQOFYvbRXK9bfWRtR1DbGFPsy6KvBt56Q1iDuWLaHusLCntuEqjZsT5u2 2mtg== X-Gm-Message-State: AOAM530xUQr18uckp0QIFV7o1Hd/WuUZxi5GyOTpM2JjlM1ZMTbtxCgI KIDg5OSieMp5DYFKLHhctLF8N5DpnMI= X-Google-Smtp-Source: ABdhPJzNLwyEg+9tyq99RrPy5wCQkzcRLPLQ3lIz9gy22FN55WX3pOp/aEaJ98d22itb7LJPDItFFg== X-Received: by 2002:a1c:398a:: with SMTP id g132mr11676386wma.38.1610822025705; Sat, 16 Jan 2021 10:33:45 -0800 (PST) Received: from [192.168.8.126] ([85.255.234.150]) by smtp.gmail.com with ESMTPSA id t16sm17364739wmi.3.2021.01.16.10.33.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 16 Jan 2021 10:33:45 -0800 (PST) Subject: Re: [PATCH v5 13/13] io_uring: support buffer registration sharing To: Bijan Mottahedeh , axboe@kernel.dk, io-uring@vger.kernel.org References: <1610487193-21374-1-git-send-email-bijan.mottahedeh@oracle.com> <1610487193-21374-14-git-send-email-bijan.mottahedeh@oracle.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: Date: Sat, 16 Jan 2021 18:30:09 +0000 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: <1610487193-21374-14-git-send-email-bijan.mottahedeh@oracle.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 12/01/2021 21:33, Bijan Mottahedeh wrote: > Implement buffer sharing among multiple rings. > > A ring shares its (future) buffer registrations at setup time with > IORING_SETUP_SHARE_BUF. A ring attaches to another ring's buffer > registration at setup time with IORING_SETUP_ATTACH_BUF, after > authenticating with the buffer registration owner's fd. Any updates to > the owner's buffer registrations become immediately available to the > attached rings. I'm thinking it through, but there is an easy to miss potential bug, so see below a comment to not forget. > > Signed-off-by: Bijan Mottahedeh > > Conflicts: > fs/io_uring.c > --- > fs/io_uring.c | 85 +++++++++++++++++++++++++++++++++++++++++-- > include/uapi/linux/io_uring.h | 2 + > 2 files changed, 83 insertions(+), 4 deletions(-) [...] > + > +static int io_init_buf_data(struct io_ring_ctx *ctx, struct io_uring_params *p) > +{ > + if ((p->flags & (IORING_SETUP_SHARE_BUF | IORING_SETUP_ATTACH_BUF)) == > + (IORING_SETUP_SHARE_BUF | IORING_SETUP_ATTACH_BUF)) > + return -EINVAL; > + > + if (p->flags & IORING_SETUP_SHARE_BUF) { > + struct fixed_rsrc_data *buf_data; > + > + buf_data = alloc_fixed_rsrc_data(ctx); > + if (IS_ERR(buf_data)) > + return PTR_ERR(buf_data); Because of sneaked through 5.11 fixes it'll be if (!buf_data) return -ENOMEM > + > + ctx->buf_data = buf_data; > + return 0; > + } > + > + if (p->flags & IORING_SETUP_ATTACH_BUF) > + return io_attach_buf_data(ctx, p); > + > + return 0; > +} > + -- Pavel Begunkov