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=-0.6 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 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 D0691C433E0 for ; Thu, 28 May 2020 18:48:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AEB8F2078C for ; Thu, 28 May 2020 18:48:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="nz7c4ojT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406005AbgE1Ssj (ORCPT ); Thu, 28 May 2020 14:48:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405916AbgE1Ssi (ORCPT ); Thu, 28 May 2020 14:48:38 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0120FC08C5C6; Thu, 28 May 2020 11:48:38 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id fs4so3659965pjb.5; Thu, 28 May 2020 11:48:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=b4Ape3M747M0VVI6j2FgoN/k0Heli3n06rVQYqA/TNo=; b=nz7c4ojTdsiLZB11V0v0F1ETriDDN/zC/Kg5tTAfDYftiGDVy8L8N2+TwfW8K7pz8q m76Qp5uKBQAxxlr4musP6u0g2tdjJksA+hrbdygAisuP7mUEd2vF3804Echg+ifmKPXd P1M8z+ZRdFc510b2DpBunRikQk6DynSvZ91iDchcOqFiYqitZtjUocX3p1IBeCz5JxKv nMhwpbn8mAEZ/LDfWk1JIO5et4YkIpJiBFC5w0WZ2fkuw0V/+aCZpPwCCyERPBJGuk0x 81u43zjy0sET8wMTSrhsUV/CyiYwHhSQR1yft0wWk2AfEYzpJzRDrH/Rbh0lcHtekOng qilg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=b4Ape3M747M0VVI6j2FgoN/k0Heli3n06rVQYqA/TNo=; b=uHFmxHRerO5JyirgWY8cwXot7OzB5p+615XRiljjQr6qDJ3Z3rzyT4lm1lS6zoRwg7 63loxyqeKpcki/UijBYKVTddXR0Jr2eg6rIXVqic2XIrrMA3QC+pU+zcdb/BIKH8pr+w /TOHa5hUZoARJvMPpLgWiSJj/SsVgbJWIWgnn8rUQ7H1+Q12lA+cAxEj+Ya3yzzcmLLC Khm/IoXAW9bw+4KPbF7Da23rkj663QdgsFhK4gvxbTSHsuynSdBlPweU+ontsky2+7Xe e67eVMeir1SzndBY43KADk7lmBWGbGRLkZA+1snI9Nol/u5YyOCvQ05lDjXjOqL0OPu/ yhQQ== X-Gm-Message-State: AOAM531UgCqpCHDzmBPo4WUYGsiLrLossmlnRx9NM2DP6eGODmvxFTnX x5ZqSs4N4fHo8afPAegoQIA= X-Google-Smtp-Source: ABdhPJx5Zd+3SZhGiDQQj821WuIcJ7M5qYK3umSaUKX0b709jUoqe1s6kO8WHly3M5GbA2cKIsWmcg== X-Received: by 2002:a17:902:c281:: with SMTP id i1mr4803445pld.177.1590691717502; Thu, 28 May 2020 11:48:37 -0700 (PDT) Received: from ast-mbp.dhcp.thefacebook.com ([2620:10d:c090:400::5:4a1c]) by smtp.gmail.com with ESMTPSA id y14sm5513470pjr.31.2020.05.28.11.48.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 May 2020 11:48:36 -0700 (PDT) Date: Thu, 28 May 2020 11:48:34 -0700 From: Alexei Starovoitov To: Andrii Nakryiko Cc: Jakub Sitnicki , bpf , Networking , kernel-team@cloudflare.com Subject: Re: [PATCH bpf-next 5/8] bpf: Add link-based BPF program attachment to network namespace Message-ID: <20200528184834.exstcynjvn3e7dli@ast-mbp.dhcp.thefacebook.com> References: <20200527170840.1768178-1-jakub@cloudflare.com> <20200527170840.1768178-6-jakub@cloudflare.com> <87pnao2qkd.fsf@cloudflare.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, May 28, 2020 at 11:09:20AM -0700, Andrii Nakryiko wrote: > > >> + net = rcu_dereference(net_link->net); > > >> + if (!net || !check_net(net)) { > > >> + /* Link auto-detached or netns dying */ > > >> + ret = -ENOLINK; > > > > > > This is an interesting error code. If we are going to adopt this, we > > > should change it for similar cgroup link situation as well. > > > > Credit goes to Lorenz for suggesting a different error code than EINVAL > > for this situation so that user-space has a way to distinguish. > > > > I'm happy to patch cgroup BPF link, if you support this change. > > Yeah, I guess let's do that. I like "link was severed" message for > that errno :) But for me it's way more about consistency, than any > specific error code. I like ENOLINK idea as well. Let's fix it there and patch older kernels via separate patch. Overall the set looks great. Looking forward to v2.