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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 23AA3C433E0 for ; Thu, 4 Jun 2020 20:27:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBB5B206C3 for ; Thu, 4 Jun 2020 20:26:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QpyL4ZRO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726266AbgFDU07 (ORCPT ); Thu, 4 Jun 2020 16:26:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725883AbgFDU07 (ORCPT ); Thu, 4 Jun 2020 16:26:59 -0400 Received: from mail-wr1-x444.google.com (mail-wr1-x444.google.com [IPv6:2a00:1450:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA950C08C5C0; Thu, 4 Jun 2020 13:26:57 -0700 (PDT) Received: by mail-wr1-x444.google.com with SMTP id j10so7504396wrw.8; Thu, 04 Jun 2020 13:26:57 -0700 (PDT) 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=NeiT4PSA5RuF4lXPzfjt4fbzeMLKUCOZ8v+zwCWEt7g=; b=QpyL4ZROWDrVQ4tds8HwCcAAZNNH33SPFta6TmANYSrqGowRfTFzPva68PonNWXlu8 ZVIj7uhV4oMApfS7Yve8rQQuCTDnCLvD9YPi55kYEu8mUlD63Pyv65llRET6HPRzg7QC 9dfqu34YenOx2rdBQMwBwfy7566tKVhBIMvHy9AymlvyW/EsIACSOy7+3OKDttTt919x Tnew9p3am+P4YxNCtM5czM+caHNdVhKCtFssyRK6ob8pBgdHKgNoR6nEwCv9XzEFb7Gr r3wrq4KhT36h+g6Kuc80Vx49ezWY1VVPAwtCyRNXFHBP0fwhSw+QV6SfIxZmaIZF+uDE A+fA== 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=NeiT4PSA5RuF4lXPzfjt4fbzeMLKUCOZ8v+zwCWEt7g=; b=bv9g5gUd05eozY8YTU8XYYWUFIFEDQ5qDUU3oSoSKFn2XYgJ/06GcERwev7nTWZSN5 o2NIK7Ka18bL/VGPFnq+DqG2OQXHEjJAcYoLv5vseulzkcSP1l95IeC3dookTQgbrGJ5 ATwlbSQeFzfdOWsirDFA+/7f3LBGfoPoaLBbvxgYRV3mgQHxc0BVLfX3doEdn9U5Iid5 zRQ6Ue3o2NxtEfY6CCE1XM5KiTkCd5cZ9v4ekRSjfLZQIhOJUGUYlxJVhZOxkgdE2LPz ud5NvqTmSOqZsuB03MHeNinGBVDCODi/y0PbXoR9J+uyKiuJ40Cwzj4UrkHlPf+DamCK +YVg== X-Gm-Message-State: AOAM532/zqNTYtEMVHYX/brlMVlrC7PBMWmBilTH/QZzaUdXcQtzlo/1 CWDqaafKyGw2/pSgDE5nqRdx8jJO X-Google-Smtp-Source: ABdhPJwjVoEH0+Qml6rnQrnesO6f0qGzzP/vN5aKsvCRQC5sl58F2MzAmik4d1KCoDfVBHbXjiYXGw== X-Received: by 2002:a5d:4841:: with SMTP id n1mr6440598wrs.64.1591302416352; Thu, 04 Jun 2020 13:26:56 -0700 (PDT) Received: from [192.168.43.208] ([5.100.193.151]) by smtp.gmail.com with ESMTPSA id i3sm9418076wrm.83.2020.06.04.13.26.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 04 Jun 2020 13:26:55 -0700 (PDT) Subject: Re: [PATCH v3 0/4] forbid fix {SQ,IO}POLL To: Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: <414b9a24-2e70-3637-0b98-10adf3636c37@kernel.dk> <947accf4-5ba1-cd39-2aeb-efb7065efb84@gmail.com> <8d817367-436b-073c-6a2c-e60830d7646e@kernel.dk> 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: <7c262b84-9404-afc1-b585-244f8c0c0918@gmail.com> Date: Thu, 4 Jun 2020 23:25:36 +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: <8d817367-436b-073c-6a2c-e60830d7646e@kernel.dk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 04/06/2020 23:17, Jens Axboe wrote: > On 6/4/20 2:12 PM, Pavel Begunkov wrote: >> On 04/06/2020 22:52, Jens Axboe wrote: >>> On 6/4/20 1:22 PM, Pavel Begunkov wrote: >>>> On 04/06/2020 20:06, Jens Axboe wrote: >>>>> On 6/3/20 12:51 PM, Jens Axboe wrote: >>>>>> On 6/3/20 9:03 AM, Pavel Begunkov wrote: >>>>>>> The first one adds checks {SQPOLL,IOPOLL}. IOPOLL check can be >>>>>>> moved in the common path later, or rethinked entirely, e.g. >>>>>>> not io_iopoll_req_issued()'ed for unsupported opcodes. >>>>>>> >>>>>>> 3 others are just cleanups on top. >>>>>>> >>>>>>> >>>>>>> v2: add IOPOLL to the whole bunch of opcodes in [1/4]. >>>>>>> dirty and effective. >>>>>>> v3: sent wrong set in v2, re-sending right one >>>>>>> >>>>>>> Pavel Begunkov (4): >>>>>>> io_uring: fix {SQ,IO}POLL with unsupported opcodes >>>>>>> io_uring: do build_open_how() only once >>>>>>> io_uring: deduplicate io_openat{,2}_prep() >>>>>>> io_uring: move send/recv IOPOLL check into prep >>>>>>> >>>>>>> fs/io_uring.c | 94 ++++++++++++++++++++++++++------------------------- >>>>>>> 1 file changed, 48 insertions(+), 46 deletions(-) >>>>>> >>>>>> Thanks, applied. >>>>> >>>>> #1 goes too far, provide/remove buffers is fine with iopoll. I'll >>>>> going to edit the patch. >>>> >>>> Conceptually it should work, but from a quick look: >>>> >>>> - io_provide_buffers() drops a ref from req->refs, which should've >>>> been used by iopoll*. E.g. io_complete_rw_iopoll() doesn't do that. >>>> >>>> - it doesn't set REQ_F_IOPOLL_COMPLETED, thus iopoll* side will >>>> call req->file->iopoll(). >>> >>> We don't poll for provide/remove buffers, or file update. The >>> completion is done inline. The REQ_F_IOPOLL_COMPLETED and friends >>> is only applicable on read/writes. >>> >> >> 1. Let io_provide_buffers() succeeds, putting a ref and returning 0 >> >> 2. io_issue_sqe() on the way back do IORING_SETUP_IOPOLL check, >> where it calls io_iopoll_req_issued(req) > > Only if req->file is valid, which it isn't for these non-file requests. Ok, it looks like I miss your commit doing ->file check there. Now sure how it slipped even though it's marked v5.7-rc7. >> >> 3. io_iopoll_req_issued() unconditionally adds the req into ->poll_list >> >> 4. io_do_iopoll() checks the req, doesn't find it flagged with >> REQ_F_IOPOLL_COMPLETED, and tries req->file->iopoll(). >> >> >> Do I miss something? Just did a quick and dirty test, which segfaulted. >> Not certain about it though. >> > > -- Pavel Begunkov