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=-8.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 165C7C43603 for ; Tue, 17 Dec 2019 18:06:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9877206EC for ; Tue, 17 Dec 2019 18:06:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="W+/QnBmV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727795AbfLQSGI (ORCPT ); Tue, 17 Dec 2019 13:06:08 -0500 Received: from mail-wm1-f66.google.com ([209.85.128.66]:37962 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727754AbfLQSGI (ORCPT ); Tue, 17 Dec 2019 13:06:08 -0500 Received: by mail-wm1-f66.google.com with SMTP id u2so4241456wmc.3; Tue, 17 Dec 2019 10:06:06 -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; bh=mmjUvTrGlgmg/mK8tJfpjSubmRW33zvn5B4Hr3L+8FI=; b=W+/QnBmVR0DGhULCYDT5/RELW2kiDUJEoDXqDDO+/FhkbPVcBlW12pyr5r8E1+ag0s La5fjueIlxQN364mVsjF9QWIfHUWxMsccZ23LFYyX58IYNhk722A22EiqC41yRg15pDv CA5slYfBVvbFbU5UuoPRf88WYibFEORR7CKCOHDpFtHC97i1mvfYefK1Gtprv1/wOkR+ CTVFrDuExnWnx3RyczBWTnl+gaUPKui7zkUr8FtzM103iBkQQeX9DbTyeg9VifRYskeg DQ/l0DLu5nq3xAEa2dNBfK4uvZ3hDNW18GZOJFgkzAIaIJ2rNa0xg4lKqunXzBjjAsA9 utJw== 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; bh=mmjUvTrGlgmg/mK8tJfpjSubmRW33zvn5B4Hr3L+8FI=; b=IOU1QE3E93it3k4eZr8wYs3yU1hNZ+UAwTQEszev8ot26vrLVphQcPbIu20Ip2roZX yUBLgL3CXu6tjq6rtyji/u5i0XhnYL8nS/xSKLsdI44Ykk/TrZmTXYf+A6B46v7CdWWT i/EQu9DMg7rV3+78NBWRxmpxgpoZcauaBQScVogrJYPvLuLZbmpOgcY2r/4EJBvThNie YpJDrZcneFKXmZB/P1RkHjeDLs/kS2BQuAX9lG3Ofor+pMiFQw4Bm4KX38NVKt0zMsc3 UV0jcFPS7UAa2a5EGVQFkxbednGfL5iTrmAS7cpv1arYeIxSJGJxq4TfJF1H8DlEEWbr FiQw== X-Gm-Message-State: APjAAAX5DYeHb1zf/canpwwMo6OBX8bySZmK1NwbAglauIuLLrYqJODV PjNNWvaqCnKw7FFd1H4QzMwBvBNT X-Google-Smtp-Source: APXvYqxTH2I8kR1/MxKfyoOwMsyRR2zg3Uzk2p2RafpoPEsIz9Pp4nX5WwGskVqKfEM8Tmac2GGJPg== X-Received: by 2002:a7b:c93a:: with SMTP id h26mr6812177wml.83.1576605965272; Tue, 17 Dec 2019 10:06:05 -0800 (PST) Received: from [192.168.43.142] ([109.126.149.134]) by smtp.gmail.com with ESMTPSA id m10sm26629648wrx.19.2019.12.17.10.06.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 17 Dec 2019 10:06:04 -0800 (PST) Subject: Re: [PATCH 3/3] io_uring: move *queue_link_head() from common path To: Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: <17f7900c-385f-0dfa-11bf-af99d080f894@gmail.com> <76917820-052d-9597-133d-424fee3edade@kernel.dk> <5d4af2f6-26a2-b241-5131-3a0155cbbf22@kernel.dk> <3b5100a7-2922-a9f2-e4e2-76252318959d@gmail.com> <7edd6631-326c-ac9c-7c5b-fa4bab3932d3@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: <4f3f9b65-6e9f-b650-65b8-1e0844321697@gmail.com> Date: Tue, 17 Dec 2019 21:05:22 +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: <7edd6631-326c-ac9c-7c5b-fa4bab3932d3@kernel.dk> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="mV0yv0PR5Hx77lVg0K9IxQ16N7dyYdSiF" Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --mV0yv0PR5Hx77lVg0K9IxQ16N7dyYdSiF Content-Type: multipart/mixed; boundary="Ta4G3Z5tSQJMt9IIrzMPhnypCQZhB7gX9"; protected-headers="v1" From: Pavel Begunkov To: Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <4f3f9b65-6e9f-b650-65b8-1e0844321697@gmail.com> Subject: Re: [PATCH 3/3] io_uring: move *queue_link_head() from common path References: <17f7900c-385f-0dfa-11bf-af99d080f894@gmail.com> <76917820-052d-9597-133d-424fee3edade@kernel.dk> <5d4af2f6-26a2-b241-5131-3a0155cbbf22@kernel.dk> <3b5100a7-2922-a9f2-e4e2-76252318959d@gmail.com> <7edd6631-326c-ac9c-7c5b-fa4bab3932d3@kernel.dk> In-Reply-To: <7edd6631-326c-ac9c-7c5b-fa4bab3932d3@kernel.dk> --Ta4G3Z5tSQJMt9IIrzMPhnypCQZhB7gX9 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 17/12/2019 21:01, Jens Axboe wrote: > On 12/17/19 10:52 AM, Pavel Begunkov wrote: >> On 17/12/2019 20:37, Jens Axboe wrote: >>> On 12/17/19 9:45 AM, Jens Axboe wrote: >>>> On 12/16/19 4:38 PM, Pavel Begunkov wrote: >>>>> On 17/12/2019 02:22, Pavel Begunkov wrote: >>>>>> Move io_queue_link_head() to links handling code in io_submit_sqe(= ), >>>>>> so it wouldn't need extra checks and would have better data locali= ty. >>>>>> >>>>>> Signed-off-by: Pavel Begunkov >>>>>> --- >>>>>> fs/io_uring.c | 32 ++++++++++++++------------------ >>>>>> 1 file changed, 14 insertions(+), 18 deletions(-) >>>>>> >>>>>> diff --git a/fs/io_uring.c b/fs/io_uring.c >>>>>> index bac9e711e38d..a880ed1409cb 100644 >>>>>> --- a/fs/io_uring.c >>>>>> +++ b/fs/io_uring.c >>>>>> @@ -3373,13 +3373,15 @@ static bool io_submit_sqe(struct io_kiocb = *req, struct io_submit_state *state, >>>>>> struct io_kiocb **link) >>>>>> { >>>>>> struct io_ring_ctx *ctx =3D req->ctx; >>>>>> + unsigned int sqe_flags; >>>>>> int ret; >>>>>> =20 >>>>>> + sqe_flags =3D READ_ONCE(req->sqe->flags); >>>>>> req->user_data =3D READ_ONCE(req->sqe->user_data); >>>>>> trace_io_uring_submit_sqe(ctx, req->user_data, true, req->in_asy= nc); >>>>>> =20 >>>>>> /* enforce forwards compatibility on users */ >>>>>> - if (unlikely(req->sqe->flags & ~SQE_VALID_FLAGS)) { >>>>>> + if (unlikely(sqe_flags & ~SQE_VALID_FLAGS)) { >>>>>> ret =3D -EINVAL; >>>>>> goto err_req; >>>>>> } >>>>>> @@ -3402,10 +3404,10 @@ static bool io_submit_sqe(struct io_kiocb = *req, struct io_submit_state *state, >>>>>> if (*link) { >>>>>> struct io_kiocb *head =3D *link; >>>>>> =20 >>>>>> - if (req->sqe->flags & IOSQE_IO_DRAIN) >>>>>> + if (sqe_flags & IOSQE_IO_DRAIN) >>>>>> head->flags |=3D REQ_F_DRAIN_LINK | REQ_F_IO_DRAIN; >>>>>> =20 >>>>>> - if (req->sqe->flags & IOSQE_IO_HARDLINK) >>>>>> + if (sqe_flags & IOSQE_IO_HARDLINK) >>>>>> req->flags |=3D REQ_F_HARDLINK; >>>>>> =20 >>>>>> if (io_alloc_async_ctx(req)) { >>>>>> @@ -3421,9 +3423,15 @@ static bool io_submit_sqe(struct io_kiocb *= req, struct io_submit_state *state, >>>>>> } >>>>>> trace_io_uring_link(ctx, req, head); >>>>>> list_add_tail(&req->link_list, &head->link_list); >>>>>> - } else if (req->sqe->flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) = { >>>>>> + >>>>>> + /* last request of a link, enqueue the link */ >>>>>> + if (!(sqe_flags & IOSQE_IO_LINK)) { >>>>> >>>>> This looks suspicious (as well as in the current revision). Returni= ng back >>>>> to my questions a few days ago can sqe->flags have IOSQE_IO_HARDLIN= K, but not >>>>> IOSQE_IO_LINK? I don't find any check. >>>>> >>>>> In other words, should it be as follows? >>>>> !(sqe_flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) >>>> >>>> Yeah, I think that should check for both. I'm fine with either appro= ach >>>> in general: >>>> >>>> - IOSQE_IO_HARDLINK must have IOSQE_IO_LINK set >>>> >>>> or >>>> >>>> - IOSQE_IO_HARDLINK implies IOSQE_IO_LINK >>>> >>>> Seems like the former is easier to verify in terms of functionality,= >>>> since we can rest easy if we check this early and -EINVAL if that is= n't >>>> the case. >>>> >>>> What do you think? >>> >>> If you agree, want to send in a patch for that for 5.5? Then I can re= spin >>> for-5.6/io_uring on top of that, and we can apply your cleanups there= =2E >>> >> Yes, that's the idea. Already got a patch, if you haven't done it yet.= >=20 > I haven't. >=20 >> Just was thinking, whether to add a check for not setting both flags >> at the same moment in the "imply" case. Would give us 1 state in 2 bit= s >> for future use. >=20 > Not sure I follow what you're saying here, can you elaborate? >=20 Sure #define IOSQE_IO_LINK (1U << 2) /* links next sqe */ #define IOSQE_IO_HARDLINK (1U << 3) /* like LINK, but stronger */ That's 2 consequent bits, so 4 states: 0,0 -> not a link 1,0 -> common link 0,1 -> hard link 1,1 -> reserved, space for another link-quirk type But that would require additional check, i.e. if (flags&(LINK|HARDLINK) =3D=3D (LINK|HARDLINK)) ... --=20 Pavel Begunkov --Ta4G3Z5tSQJMt9IIrzMPhnypCQZhB7gX9-- --mV0yv0PR5Hx77lVg0K9IxQ16N7dyYdSiF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE+6JuPTjTbx479o3OWt5b1Glr+6UFAl35GOIACgkQWt5b1Glr +6VSxw//Sl7VRymYnHXAY1x8MgEzO335Jdu/kdda0vgREqNK342DvoEKdIYRELH3 jbsrscjnE/UrHX7itTewSF1vIVq+u2XweT7buNdMsSNT9Q1wgEGR2nAkP0UoKc9Y OqxY1uMC9pwFIMI/Nxt4FYwSKM8K4wHCB5UAiTZa/JGUX524WMD6rlZeQbAeV1z6 h1Uc4juLrdHIT1YqdoPTo+9/ffpb+JHW998X+ozignfN00zq/fN48le0YjervjtS GZsLq9/fRorRbXovUxav6Vh3007sFcnTLB20KgwLmHhujlH5DIYomyr7r/N3QpIR dMxm2arl4C2UporRH54AxPeUv2CwjaZjVOCOSU44VS6FgskSRm4RmxTp+asSIFQD XbZUODHElyJBicVvBkJrE+z9FEFN6L+5KpA0jGSJaLjSk1+lGsERUAol/ykJYfWe rVJbaYugck9PHhi55NO55KsUdlaDnz5wx8cAx6oFBnUxHDQcdU2PAsYMup19/zQV dUxN8WGEFb04OiVYO4FR+5tKaqbaG8EQAldTXuiLuBxghNTUlBV1q0HW7KoHR/w8 tp4OiVQ6ADT7NgtkU+VHFqymvkG5m3ZAiBfruAzsmVzdLfQoQdTJNHEiTCsB/Wrx PMp33ffZ9fKBzqY7A/gpnGdPoCz7QiAduAIkXlKxc+0Iv6bY5ao= =7SRS -----END PGP SIGNATURE----- --mV0yv0PR5Hx77lVg0K9IxQ16N7dyYdSiF--