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 9EB34C433EF for ; Wed, 23 Mar 2022 20:14:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344584AbiCWUP4 (ORCPT ); Wed, 23 Mar 2022 16:15:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344579AbiCWUPz (ORCPT ); Wed, 23 Mar 2022 16:15:55 -0400 Received: from mail-ej1-x634.google.com (mail-ej1-x634.google.com [IPv6:2a00:1450:4864:20::634]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B3F78C7CE; Wed, 23 Mar 2022 13:14:23 -0700 (PDT) Received: by mail-ej1-x634.google.com with SMTP id yy13so5133807ejb.2; Wed, 23 Mar 2022 13:14:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=vUP+cDU6A63BiCB5No7G9vTRFHC0WfO/ACql60JcDZ4=; b=Uymv0AnoffsesJkU/vB9EPFV7fHYvGysg0Ebp/hmGaGcs6n+SDrkBCEUVrNzstO3p0 UgO0DcN9wZbez+Hd3bwRws4pny+z1IFrCXCn2K5+9JLzjH41IKgErmKFEfsgguuDcf47 sXzlTEEDDaq6O1vNaBDHlNz5JVPzPXw/XIQLM4ujqjpLh1f7yM6fy+lroM4mvovC3tkM Cv/w/9imHIyQzEcJbZbvzReuVDIKceP3f3dPhsRbGtAAlfTYTRbbWT/uVSA1gD6CHXe+ aCfcEMXG4SSzTBlZzjCSgKZrTlZPXBsmAziS3rbtUWTG46kmU1j109pWCxG5vn/mhokm wMQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=vUP+cDU6A63BiCB5No7G9vTRFHC0WfO/ACql60JcDZ4=; b=dFl2nH9MPt5cWvTo2+AFRHkPuW/Mu2Ndm+nw3rtqtV7JHlVj8X1gUgFm75zP79KyhX y/lWu4hGCO/rVGeuMgXZAO5RWE2DDlWUdFKd+1kr93JLDSJZO7wIiGzid034zWqRgVK8 XudYWnwrxRNA0Lojj/qOHFqUObro0U9lTXePo3WvTdldaIBOZQrw37LqQfRcraXiufaP /g8zLmOHiaGatI0xDheY6lF45Hfnlk+2aeT1MrYvmqVEU5QxagfikTxztFYaza9DQanG ZN1WEKka9pQwmtzuplFLWFT5rRbzFKlCdnXsIZ1bZVgyfY6iqskvbI60HWxtZYlQjV1f ua+w== X-Gm-Message-State: AOAM531cWeTKUjLnDAVWcW7/kK4ZtfJWuG8+Ti+peZZVzvwm2JNa3Mqg Th9qTG1ifder6NULanJT5Gg= X-Google-Smtp-Source: ABdhPJy8/R1UwCohZhHy/oCfb9hBRA6tKwPHZexu/TtgXp3lESESoLy43PqmzjFrzUyKiXKNI239zA== X-Received: by 2002:a17:906:30d1:b0:6cf:c116:c9d3 with SMTP id b17-20020a17090630d100b006cfc116c9d3mr1850615ejb.245.1648066461644; Wed, 23 Mar 2022 13:14:21 -0700 (PDT) Received: from [192.168.1.114] ([85.105.239.232]) by smtp.gmail.com with ESMTPSA id x12-20020a50d9cc000000b0040f70fe78f3sm424439edj.36.2022.03.23.13.14.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 23 Mar 2022 13:14:21 -0700 (PDT) Message-ID: <64197456-87f2-e780-186d-272e06ae223b@gmail.com> Date: Wed, 23 Mar 2022 20:13:09 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.6.0 Subject: Re: [PATCH 1/2] io_uring: ensure recv and recvmsg handle MSG_WAITALL correctly Content-Language: en-US To: Jens Axboe , io-uring@vger.kernel.org Cc: constantine.gavrilov@gmail.com, stable@vger.kernel.org References: <20220323153947.142692-1-axboe@kernel.dk> <20220323153947.142692-2-axboe@kernel.dk> From: Pavel Begunkov In-Reply-To: <20220323153947.142692-2-axboe@kernel.dk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 3/23/22 15:39, Jens Axboe wrote: > We currently don't attempt to get the full asked for length even if > MSG_WAITALL is set, if we get a partial receive. If we do see a partial > receive, then just note how many bytes we did and return -EAGAIN to > get it retried. > > The iov is advanced appropriately for the vector based case, and we > manually bump the buffer and remainder for the non-vector case. How datagrams work with MSG_WAITALL? I highly doubt it coalesces 2+ packets to satisfy the length requirement (e.g. because it may move the address back into the userspace). I'm mainly afraid about breaking io_uring users who are using the flag just to fail links when there is not enough data in a packet. -- Pavel Begunkov