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=-17.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 3B815C11F68 for ; Fri, 2 Jul 2021 10:29:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2278061420 for ; Fri, 2 Jul 2021 10:29:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231452AbhGBKcM (ORCPT ); Fri, 2 Jul 2021 06:32:12 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:30908 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230373AbhGBKcL (ORCPT ); Fri, 2 Jul 2021 06:32:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625221778; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DPxMNn2CCE4cxpTvsVh+CYPLZZTodxuHXGUXkbr4MMw=; b=J+3mHCuS+6c0bFEgHQALhqxkHp32DumMACx9d7cpcfDVK1u5j2xT9YKtX3aRTUpibvNoBT vS5dmburJQhUMuqK0pRsJY6YcTDj5FtWereFb9qGwd3LV+KuDrBPclCzUA3gnDkyIe0uK/ dAx0lIiXJCZhsamVwLoT5H/Jj2YvyMA= Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-61-_Yrq6Ii4OnayCB80OIuUNg-1; Fri, 02 Jul 2021 06:29:37 -0400 X-MC-Unique: _Yrq6Ii4OnayCB80OIuUNg-1 Received: by mail-ed1-f72.google.com with SMTP id r15-20020aa7da0f0000b02903946a530334so4867068eds.22 for ; Fri, 02 Jul 2021 03:29:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:subject:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=DPxMNn2CCE4cxpTvsVh+CYPLZZTodxuHXGUXkbr4MMw=; b=NYs+FQ4Ucs9bLxdf2i2aMoywnuEHTOg+y9AGKWHnrsgzJaSHu64uG8cwPhVzBpc0qW WhOxREVlCseMc2s405rWUXYgAUBWMuUny3HJCzbonVlUfpUMFaelnwhZCu/WbBccJbYH SAgPvo7UrhPaYUQcJeM1mXEIUQdl/Rvf9/XQz33x4rfVzbHHo1wecUuqfNZ3oaKHvPlC zbqmLyRIUQeHq6nwKoe0li2eJld/oNLFFS2D33M4CWbXaZh7J0M3hTk2vVvNwX8if4au ZrhgK0iKhnQxj3rC33qzD2PQFqb0yV1GnAxkozNKdm5Y9Kt5q+dWirPybAbiTsAjM5t0 35DA== X-Gm-Message-State: AOAM530Y0L4p3kh5pRwURaCpaVp98WGH86GF27SIxF3HXqzTC/rCIYcA M0wtqKfOy5/06gckFKABFHU1w7kZxwR57A5ueXOeWPeJVijnc+Yt6RZj0pG9hTWFlBmPYy3TtrZ MoV4610a+rohYhUfI30DA3G1wNI1dnEXDibnq4xVTHGxjOkwZLO1qRgw1tI+DEM7BV0u2aD+d50 Y= X-Received: by 2002:a05:6402:2813:: with SMTP id h19mr5739026ede.39.1625221776664; Fri, 02 Jul 2021 03:29:36 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyeTV7Vr11aiyTEXIqNuKKngfk6mHPBCj/YJvYik4FkcZfq09iNjgHFyinId+fVKL5hjUuW0Q== X-Received: by 2002:a05:6402:2813:: with SMTP id h19mr5739002ede.39.1625221776482; Fri, 02 Jul 2021 03:29:36 -0700 (PDT) Received: from [192.168.42.238] (3-14-107-185.static.kviknet.dk. [185.107.14.3]) by smtp.gmail.com with ESMTPSA id br4sm666879ejb.110.2021.07.02.03.29.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 02 Jul 2021 03:29:36 -0700 (PDT) From: Jesper Dangaard Brouer X-Google-Original-From: Jesper Dangaard Brouer Subject: Re: [PATCH bpf] samples/bpf: Fix the error return code of xdp_redirect's main() To: Wang Hai , davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, kpsingh@kernel.org Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210616042534.315097-1-wanghai38@huawei.com> Message-ID: <94aad4ed-8384-1841-88ec-6c7e39d63148@redhat.com> Date: Fri, 2 Jul 2021 12:29:35 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210616042534.315097-1-wanghai38@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16/06/2021 06.25, Wang Hai wrote: > Fix to return a negative error code from the error handling > case instead of 0, as done elsewhere in this function. The main() function in C should never return a negative value on Unix POSIX systems. There is a good explaination in exit(3p): `man 3p exit`    The  value  of  status may be 0, EXIT_SUCCESS, EXIT_FAILURE, or any other value, though only the least significant 8 bits (that is, status & 0377) shall be available to a waiting parent process. Thus, negative values are often seen as 255 in the $? program exit status variable $?. Also explained in exit(3):     The C standard specifies two constants, EXIT_SUCCESS=0 and EXIT_FAILURE=1. I see the 'samples/bpf/xdp_redirect_user.c' in most places just use 0 or 1. > If bpf_map_update_elem() failed, main() should return a negative error. > > Fixes: 832622e6bd18 ("xdp: sample program for new bpf_redirect helper") > Signed-off-by: Wang Hai > --- > samples/bpf/xdp_redirect_user.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/samples/bpf/xdp_redirect_user.c b/samples/bpf/xdp_redirect_user.c > index 41d705c3a1f7..c903f1ccc15e 100644 > --- a/samples/bpf/xdp_redirect_user.c > +++ b/samples/bpf/xdp_redirect_user.c > @@ -213,5 +213,5 @@ int main(int argc, char **argv) > poll_stats(2, ifindex_out); > > out: > - return 0; > + return ret; > } (Sorry, I didn't complain it time as I see this patch is already applied)