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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B693C77B6F for ; Tue, 11 Apr 2023 15:29:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230494AbjDKP3Z (ORCPT ); Tue, 11 Apr 2023 11:29:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230053AbjDKP3X (ORCPT ); Tue, 11 Apr 2023 11:29:23 -0400 Received: from mail-io1-xd2c.google.com (mail-io1-xd2c.google.com [IPv6:2607:f8b0:4864:20::d2c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 31F65526C for ; Tue, 11 Apr 2023 08:29:17 -0700 (PDT) Received: by mail-io1-xd2c.google.com with SMTP id ca18e2360f4ac-7606d7ca422so4687639f.1 for ; Tue, 11 Apr 2023 08:29:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; t=1681226956; x=1683818956; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=LY7YABVANJBpnoGShMcSEGz2zmHaSs72D2YD+dvEB/o=; b=ZWrZYfxohRGNPyYVlwzZUd5gQvb0wTWEee+Sxa0LCjDgo/Nx9goOCVGN1ZhnS2P0jL i5DPkiH3Puod6ziLgypR/OS5UxpWT2TBfaSCSpCF+tHebPCFT7ESdPLULIunYzFtzNW/ k31xn+gNlN+5maMjymgBg5DTnosmu/WZnPXv5IgkBgn/BI2t4I5B+vC9/zSJIQS67DbX HjtA/YuQ3zHqcqjx9MTEwJMU0YbMKcVmB/gJMBfo+kMTvxVMGOdinj5BHkVRobw1fnH6 YAPqyTXFdGmroG0hI2ZCyRs4Va2oHUoCSrVqj4IGVYvCyByZSsFDcrIuCEqU3odnT9Tw qw6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1681226956; x=1683818956; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=LY7YABVANJBpnoGShMcSEGz2zmHaSs72D2YD+dvEB/o=; b=yzdwsEGm7tpWRmuMkS/zXxEhClqUFyLPZfO80xfEP7ADAAfgu2TV4r1gPokFktG0bU K44ux1bucrFu0ut2vnT82uSDvuvOTcs4dNI6piFYoe3lVsSX9CpqTCWOxcn22YU3J2QF lKMqcq4jEg0rmBEfUkVe6iIFX8PXZNk5cw2L0UNNjQkgHlVEXrcWVSOLLaf1vZgcGpbT EAopZYd3do4sVIJW1tqs0bPARsxsPLXkG/Ez1tVuy0MeQlPcu/UjkeuMeRmC0XGU5Mpa bcISh/ddBT7aSG7I3cRZucphUeKgQ41FEG+Zc09dxMznACmVhS4/NOTNU9WaOUcmmiFM 4QYQ== X-Gm-Message-State: AAQBX9esjk5HCwf5Dmxd9lNyp0pYdoPix8ZEt2sU3FrxLS4c1omUlmg+ HVZ48D5t+WcAvSpbRDWdWCKCKw== X-Google-Smtp-Source: AKy350YTQzwtVs+fobpu4VlZXmN6QjQ8Crt7xuEhF8qtkl8AUI5eJ6G7pwRhzeqzoKUNI7xlvPDHKg== X-Received: by 2002:a05:6602:2d08:b0:758:9dcb:5d1a with SMTP id c8-20020a0566022d0800b007589dcb5d1amr6232653iow.2.1681226956457; Tue, 11 Apr 2023 08:29:16 -0700 (PDT) Received: from [192.168.1.94] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id h35-20020a05663833a300b0040bce6160e1sm1554966jav.12.2023.04.11.08.29.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 11 Apr 2023 08:29:16 -0700 (PDT) Message-ID: <78abce6b-709b-7309-2ee1-5370d05748b6@kernel.dk> Date: Tue, 11 Apr 2023 09:29:15 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH 0/5] add initial io_uring_cmd support for sockets Content-Language: en-US To: David Ahern , Breno Leitao Cc: Willem de Bruijn , io-uring@vger.kernel.org, netdev@vger.kernel.org, kuba@kernel.org, asml.silence@gmail.com, leit@fb.com, edumazet@google.com, pabeni@redhat.com, davem@davemloft.net, dccp@vger.kernel.org, mptcp@lists.linux.dev, linux-kernel@vger.kernel.org, willemdebruijn.kernel@gmail.com, matthieu.baerts@tessares.net, marcelo.leitner@gmail.com References: <20230406144330.1932798-1-leitao@debian.org> <75e3c434-eb8b-66e5-5768-ca0f906979a1@kernel.org> <67831406-8d2f-feff-f56b-d0f002a95d96@kernel.dk> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 4/11/23 9:27?AM, David Ahern wrote: > On 4/11/23 9:17 AM, Jens Axboe wrote: >> On 4/11/23 9:10?AM, David Ahern wrote: >>> On 4/11/23 8:41 AM, Jens Axboe wrote: >>>> On 4/11/23 8:36?AM, David Ahern wrote: >>>>> On 4/11/23 6:00 AM, Breno Leitao wrote: >>>>>> I am not sure if avoiding io_uring details in network code is possible. >>>>>> >>>>>> The "struct proto"->uring_cmd callback implementation (tcp_uring_cmd() >>>>>> in the TCP case) could be somewhere else, such as in the io_uring/ >>>>>> directory, but, I think it might be cleaner if these implementations are >>>>>> closer to function assignment (in the network subsystem). >>>>>> >>>>>> And this function (tcp_uring_cmd() for instance) is the one that I am >>>>>> planning to map io_uring CMDs to ioctls. Such as SOCKET_URING_OP_SIOCINQ >>>>>> -> SIOCINQ. >>>>>> >>>>>> Please let me know if you have any other idea in mind. >>>>> >>>>> I am not convinced that this io_uring_cmd is needed. This is one >>>>> in-kernel subsystem calling into another, and there are APIs for that. >>>>> All of this set is ioctl based and as Willem noted a little refactoring >>>>> separates the get_user/put_user out so that in-kernel can call can be >>>>> made with existing ops. >>>> >>>> How do you want to wire it up then? We can't use fops->unlocked_ioctl() >>>> obviously, and we already have ->uring_cmd() for this purpose. >>>> >>>> I do think the right thing to do is have a common helper that returns >>>> whatever value you want (or sets it), and split the ioctl parts into a >>>> wrapper around that that simply copies in/out as needed. Then >>>> ->uring_cmd() could call that, or you could some exported function that >>>> does supports that. >>>> >>>> This works for the basic cases, though I do suspect we'll want to go >>>> down the ->uring_cmd() at some point for more advanced cases or cases >>>> that cannot sanely be done in an ioctl fashion. >>>> >>> >>> My meta point is that there are uapis today to return this information >>> to applications (and I suspect this is just the start of more networking >>> changes - both data retrieval and adjusting settings). io_uring is >>> wanting to do this on behalf of the application without a syscall. That >>> makes io_uring yet another subsystem / component managing a socket. Any >>> change to the networking stack required by io_uring should be usable by >>> all other in-kernel socket owners or managers. ie., there is no reason >>> for io_uring specific code here. >> >> I think we are in violent agreement here, what I'm describing is exactly >> that - it'd make ioctl/{set,get}sockopt call into the same helpers that >> ->uring_cmd() would, with the only difference being that the former >> would need copy in/out and the latter would not. >> >> But let me just stress that for direct descriptors, we cannot currently >> call ioctl or set/getsockopt. This means we have to instantiate a >> regular descriptor first, do those things, then register it to never use >> the regular file descriptor again. That's wasteful, and this is what we >> want to enable (direct use of ioctl set/getsockopt WITHOUT a normal file >> descriptor). It's not just for "oh it'd be handy to also do this from >> io_uring" even if that would be a worthwhile goal in itself. >> > > Christoph's patch set a few years back that removed set_fs broke the > ability to do in-kernel ioctl and {s,g}setsockopt calls. I did not > follow that change; was it a deliberate intent to not allow these > in-kernel calls vs wanting to remove the set_fs? e.g., can we add a > kioctl variant for in-kernel use of the APIs? I think it'd be much better to cleanly split it out rather than try and hack around it. -- Jens Axboe