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 0EF89C47255 for ; Sun, 10 May 2020 00:30:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD20B20722 for ; Sun, 10 May 2020 00:30:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Lyr7Gu5A" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728772AbgEJAal (ORCPT ); Sat, 9 May 2020 20:30:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726356AbgEJAal (ORCPT ); Sat, 9 May 2020 20:30:41 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B19EC061A0C; Sat, 9 May 2020 17:30:39 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id d22so2714799pgk.3; Sat, 09 May 2020 17:30:39 -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=1TnOjzAhaCG9wfDY8OdCpYMCZYj6rLcaf71uTBktBf4=; b=Lyr7Gu5AuMuU9rVrbGtScXaswAmFWHpkOoI4QZ+toMPsTt5F0Kp4/y/mYQXw9V+gHl u0HyZEVbEwyKNWo1lubWjhSJja9+c0/Lw19HEaAIo2ZskZciGNxyzV7jKkQdPNAu1JTu DU8CkeWdmw+LltBDqTya6D6rq8CSymECGvEMekHnBwosdFYV0w0pEG4jtuclcTcK0Lwz YahejnDakW9GjaDrHbi5bFwzveL6+Kr5XP4YXloCkIKFbe96lMszepmkCGcthrNr9YX9 hQJAAqSn8GmMkDptHqK0uPUQro8hBEey+zYplYXnW4vY8K26ZmG5Xg7QwrLhm90kUHB6 IugA== 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=1TnOjzAhaCG9wfDY8OdCpYMCZYj6rLcaf71uTBktBf4=; b=PiiUATMRTZOEwzSKKRu/FxoKA0R6cOmdFyvnx/PD1F0aYbBiO1IYPF06YvnJzvadYq NnxOOAxK1kREfIUVwCA7HUG+k3nWb/X0f0AP29oPjmpk7q0RKkDyLPXvVNA6TNTpRzJ8 Z7rAKnTFjXG45iI6KftkS9WOlcL0qRMUnbe6dsICQDzOE74KmhRPmRbTHoBbf6TIHBh6 NLcBT9EnATOmLVKONv5VVDPa9umB87cCUvjVoswUMj/1x9qBcJGip919N54pH4byN+cJ rdsVsY44lCQpilJakAW1FwC04vX/e/jVwz/6GG5ap4wP0EHA9/25A7lYlh2oKyltrgwI b9/Q== X-Gm-Message-State: AGi0PuZzLDXPu5awU1p/I7pHsjl4U7n5ImIk3TzxYOmsYicq31nZNqOp MFy99fqxgh8IzLAvImWH5UI= X-Google-Smtp-Source: APiQypIwMtb5CIsnCLEvtBSto/KEoPx9gGCZybIg1Zj53CflCmi6ym3m8DuiNQgxKI7Z8bLXfukNeQ== X-Received: by 2002:a63:e602:: with SMTP id g2mr8485819pgh.380.1589070639066; Sat, 09 May 2020 17:30:39 -0700 (PDT) Received: from ast-mbp ([2620:10d:c090:400::5:7bdb]) by smtp.gmail.com with ESMTPSA id o9sm5926080pje.47.2020.05.09.17.30.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 09 May 2020 17:30:38 -0700 (PDT) Date: Sat, 9 May 2020 17:30:36 -0700 From: Alexei Starovoitov To: Yonghong Song Cc: Andrii Nakryiko , bpf@vger.kernel.org, Martin KaFai Lau , netdev@vger.kernel.org, Alexei Starovoitov , Daniel Borkmann , kernel-team@fb.com Subject: Re: [PATCH bpf-next v4 05/21] bpf: implement bpf_seq_read() for bpf iterator Message-ID: <20200510003036.3xzunae5nd75ckc2@ast-mbp> References: <20200509175859.2474608-1-yhs@fb.com> <20200509175904.2475468-1-yhs@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200509175904.2475468-1-yhs@fb.com> Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Sat, May 09, 2020 at 10:59:04AM -0700, Yonghong Song wrote: > + > + err = seq->op->show(seq, p); > + if (err > 0) { > + seq->count = offs; as far as I can see this condition can never happen. I understand that seq_read() has this logic, but four iterators implemented don't exercise this path. I guess it's ok to keep it, but may be add warn_once so we notice when things change?