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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 904B2C433B4 for ; Tue, 18 May 2021 04:46:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68B3A61028 for ; Tue, 18 May 2021 04:46:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240801AbhERErx (ORCPT ); Tue, 18 May 2021 00:47:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35478 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239559AbhERErw (ORCPT ); Tue, 18 May 2021 00:47:52 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72C89C061573; Mon, 17 May 2021 21:46:35 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id cu11-20020a17090afa8bb029015d5d5d2175so828782pjb.3; Mon, 17 May 2021 21:46:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=sQNZf7rDSs5L4UF53pIulq/HEniCHBE6M/99uTQIboA=; b=W+dLLwJbPu1kKukzz6V2PruQ4fBijCJisRjCnYytaBZWeTjTQGgYSDBQLyEnMEp1rE QOAc1XP1csQ3YF1aNeYzGILI/hkTNeSh4PVZSmzctMKBHp3rslviegz3FLtTB5U64neu SF3pXTMGb0+wpThvWsXJWZobcZ0X+PjzPzY+4oE7dxGXjsbPR+H19QagsRdAwERlvh+Z FUSOmmH/Sih1EgeUAFhjJ+U2WUj7vlYdKiS4JT2XXxF93dhYjlhPRiBi6NTS7DrzFxBP tiQQCz35N0dy1p7/7F1NyM13RRLzpow5MTEYND5TQbBCcWEOftGasPdlkUGyp53zePPo +8CA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=sQNZf7rDSs5L4UF53pIulq/HEniCHBE6M/99uTQIboA=; b=nXwXRbsEjLBmDpQ6/g7VkwU1axsrZsnJQ+0/s7IPy+Pjk1vpvfqPG71xceo1myQeqa TtbXDJki02ErhnSI71c9hB2NvHlZo6+dawHpURxnQt1/Dsa2H8apndy8LL1jtk+HrI/E HskrNzjM7zGeqoJ5T5QuMJFecKnhLB/c/Y0+UTI+MoPS9/BwQbAEvXavM0s3mRjRCiDY mvbf/fRr3KufyU/feP/Hg5j7877Fh83pCzz3xL2zs3U6zhYw2SThjLQTnw6FhcFfhtxn /U3FWd5GBT3BA9rdXJEy5ovrY9mNFnSIbR+ooam7rjILU1TxI0wIMdDpn7aQiabHtgu1 9r0w== X-Gm-Message-State: AOAM532p0+DiDzxAatTrOOGsQs6h8EShCpvHT4A1LbOQo8nVh6z3q6FL WdCX/dfgI5BhP1d8KQkkxnEA+EFBIiyKRiciCZgu55hy9Byg5pRj X-Google-Smtp-Source: ABdhPJwwkV6hsSHjbrjD1U7ZoIJkgl2mA8jYx1d3bULUPdJvyxgXmgfa0zADh2x21saxBC1HUkvGXjvLZiQf/NF/9e0= X-Received: by 2002:a17:90a:e2cb:: with SMTP id fr11mr3417543pjb.56.1621313194880; Mon, 17 May 2021 21:46:34 -0700 (PDT) MIME-Version: 1.0 References: <20210426025001.7899-1-xiyou.wangcong@gmail.com> <20210426025001.7899-3-xiyou.wangcong@gmail.com> <609a1765cf6d7_876892080@john-XPS-13-9370.notmuch> In-Reply-To: <609a1765cf6d7_876892080@john-XPS-13-9370.notmuch> From: Cong Wang Date: Mon, 17 May 2021 21:46:24 -0700 Message-ID: Subject: Re: [Patch bpf-next v3 02/10] af_unix: implement ->read_sock() for sockmap To: John Fastabend Cc: Linux Kernel Network Developers , bpf , Jiang Wang , Xiongchun Duan , Dongdong Wang , Cong Wang , Daniel Borkmann , Jakub Sitnicki , Lorenz Bauer Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Mon, May 10, 2021 at 10:34 PM John Fastabend wrote: > > +static int unix_read_sock(struct sock *sk, read_descriptor_t *desc, > > + sk_read_actor_t recv_actor) > > +{ > > + int copied = 0; > > + > > + while (1) { > > + struct unix_sock *u = unix_sk(sk); > > + struct sk_buff *skb; > > + int used, err; > > + > > + mutex_lock(&u->iolock); > > + skb = skb_recv_datagram(sk, 0, 1, &err); > > + if (!skb) { > > + mutex_unlock(&u->iolock); > > + return err; > > Here we should check copied and break if copied is >0. Sure the caller here > has desc.count = 1 but its still fairly fragile. Technically, sockmap does not even care about what we return here, so I am sure what you suggest here even makes a difference. Also, desc->count is always 1 and never changes here. Thanks.