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=-8.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 AA93EC2D0A3 for ; Fri, 6 Nov 2020 10:50:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5D1552072E for ; Fri, 6 Nov 2020 10:50:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727067AbgKFKuZ (ORCPT ); Fri, 6 Nov 2020 05:50:25 -0500 Received: from imap3.hz.codethink.co.uk ([176.9.8.87]:34498 "EHLO imap3.hz.codethink.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726317AbgKFKuZ (ORCPT ); Fri, 6 Nov 2020 05:50:25 -0500 X-Greylist: delayed 1489 seconds by postgrey-1.27 at vger.kernel.org; Fri, 06 Nov 2020 05:50:23 EST Received: from host-92-5-241-147.as43234.net ([92.5.241.147] helo=[192.168.1.13]) by imap3.hz.codethink.co.uk with esmtpsa (Exim 4.92 #3 (Debian)) id 1kayvz-00071a-Sl; Fri, 06 Nov 2020 10:25:31 +0000 Subject: Re: [linux-safety] [PATCH] taskstats: remove unneeded dead assignment To: Lukas Bulwahn , Balbir Singh Cc: Tom Rix , Nathan Chancellor , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-janitors@vger.kernel.org, linux-safety@lists.elisa.tech, linux-kernel@vger.kernel.org References: <20201106062210.27920-1-lukas.bulwahn@gmail.com> From: Sudip Mukherjee Message-ID: <6ab2415b-0642-16ee-4be0-c909e07e7565@codethink.co.uk> Date: Fri, 6 Nov 2020 10:25:30 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20201106062210.27920-1-lukas.bulwahn@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Lukas, On 06/11/2020 06:22, Lukas Bulwahn wrote: > make clang-analyzer on x86_64 defconfig caught my attention with: > > kernel/taskstats.c:120:2: warning: Value stored to 'rc' is never read \ > [clang-analyzer-deadcode.DeadStores] > rc = 0; > ^ > > Commit d94a041519f3 ("taskstats: free skb, avoid returns in > send_cpu_listeners") made send_cpu_listeners() not return a value and > hence, the rc variable remained only to be used within the loop where > it is always assigned before read and it does not need any other > initialisation. > > So, simply remove this unneeded dead initializing assignment. Might be better to remove 'rc' completely as it is only used for the if condition now. diff --git a/kernel/taskstats.c b/kernel/taskstats.c index a2802b6ff4bb..63541f1ae04a 100644 --- a/kernel/taskstats.c +++ b/kernel/taskstats.c @@ -113,11 +113,10 @@ static void send_cpu_listeners(struct sk_buff *skb, struct listener *s, *tmp; struct sk_buff *skb_next, *skb_cur = skb; void *reply = genlmsg_data(genlhdr); - int rc, delcount = 0; + int delcount = 0; genlmsg_end(skb, reply); - rc = 0; down_read(&listeners->sem); list_for_each_entry(s, &listeners->list, list) { skb_next = NULL; @@ -126,8 +125,8 @@ static void send_cpu_listeners(struct sk_buff *skb, if (!skb_next) break; } - rc = genlmsg_unicast(&init_net, skb_cur, s->pid); - if (rc == -ECONNREFUSED) { + if (genlmsg_unicast(&init_net, skb_cur, s->pid) == + -ECONNREFUSED) { s->valid = 0; delcount++; } -- Regards Sudip