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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 4DEACC2D0A8 for ; Mon, 28 Sep 2020 10:00:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF4EE20757 for ; Mon, 28 Sep 2020 10:00:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="R+pfU0To" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726668AbgI1KAP (ORCPT ); Mon, 28 Sep 2020 06:00:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54846 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726540AbgI1KAP (ORCPT ); Mon, 28 Sep 2020 06:00:15 -0400 Received: from mail-ed1-x541.google.com (mail-ed1-x541.google.com [IPv6:2a00:1450:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2863EC061755; Mon, 28 Sep 2020 03:00:15 -0700 (PDT) Received: by mail-ed1-x541.google.com with SMTP id e22so623345edq.6; Mon, 28 Sep 2020 03:00:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=SDDq2C7QLWNFyYFepbxAMacpxOBVCHMbzny/kHBr8TA=; b=R+pfU0Towmle8RJu/D2uVB6nF3nenvlxVFjiSEvSkMiG2Jlx3yvjSATbQ8+uGNBHHC /hxaVJSDGW/iXOGt0AzwAPlvP3FQWFp7uRePLRzNFXLrjI0cUmxzmB/Yo4f7rU2w/PgF QZZNVcmw/iC5SfxzSz2omZ3VEyF9P6mf8kLWBPl9DmsXVXIn00jKeEf2rX03yd0uCEhx cbYV3TC7vuKlE6QYK63WE8mIThW1ugvgD3GoYFnmga8LP66ybx8Bj4VvIj9Td0U8GFtB Lo3a8nFWXq4UkVdkgbsrgexuhXTY65G8VOE+r0bL/pwSau4c2qfKMF3pZa37/VqccADC 1MIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=SDDq2C7QLWNFyYFepbxAMacpxOBVCHMbzny/kHBr8TA=; b=dJSzkyNBWRcTnfFiVDEbtvAQdQfpTaPueibQ03JLXJbV5SPo592vnkF5K/RONPLUS7 MQ2fikQYB4X93JzmOt9NI+KNLwQOLt9rqyA/s6GWvLbWdKFKko56uJVrtwPqI5zRtw7r qQ2sqnvEsU9NHsWXyvVgn8MCijSmy+LlHlOLmJ9fbqISNyi6hoOHdeFTcSVGXqionyT3 PJj1yU2dTvliGSvEwqo+VaHyNJCZ8W1I8X/FlZjdZqjqqS9e5oQOWcRvQQpfrwt4etqn zAwrgQafwogYfdb83Seq9lxAVMTCxFzNlqcGdlvmwCP4/1BYg4szY8ucKl+7LQf/5ob6 WNsg== X-Gm-Message-State: AOAM530JMy8DwAjBAn+ry+JRfAmzu7VmHxteMehHg+m5wNyg0H9H0GZM IskSu4cl8AtZJSX9BCmS7yI= X-Google-Smtp-Source: ABdhPJzlWRLg1EMg817RKK+Ds6y/qvJKdNZ7zwAaJGbykb2KswiX5HBOGUqqOfFCatcJ6+iB3eFoOQ== X-Received: by 2002:a05:6402:1d93:: with SMTP id dk19mr800943edb.198.1601287213821; Mon, 28 Sep 2020 03:00:13 -0700 (PDT) Received: from felia.fritz.box ([2001:16b8:2d9d:5000:7872:7299:adfa:b749]) by smtp.gmail.com with ESMTPSA id m10sm921048edf.11.2020.09.28.03.00.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Sep 2020 03:00:13 -0700 (PDT) From: Lukas Bulwahn To: Dave Hansen , Andy Lutomirski , Peter Zijlstra Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Nathan Chancellor , Nick Desaulniers , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, kernel-janitors@vger.kernel.org, linux-safety@lists.elisa.tech, Lukas Bulwahn Subject: [PATCH] x86/mm: drop superfluous initialization Date: Mon, 28 Sep 2020 12:00:04 +0200 Message-Id: <20200928100004.25674-1-lukas.bulwahn@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It is not required to initialize the local variable start in memory_map_top_down(), as the variable will be initialized in any path before it is used. make clang-analyzer on x86_64 tinyconfig reports: arch/x86/mm/init.c:612:15: warning: Although the value stored to 'start' \ is used in the enclosing expression, the value is never actually read \ from 'start' [clang-analyzer-deadcode.DeadStores] Compilers will detect this superfluous assignment and optimize that expression anyway. So, the resulting binary is identical before and after the change. Drop this superfluous assignment to make clang-analyzer happy. No functional change. Signed-off-by: Lukas Bulwahn --- applies cleanly on v5.9-rc7 and next-20200925 Dave, Andy, Peter, please pick this minor non-urgent clean-up patch. I quickly confirmed that the binary did not change with this change to the source code; the hash of init.o remained the same before and after the change. So, in my setup: md5sum arch/x86/mm/init.o b26f6380760f32d2ef2c7525301eebd3 init.o linux-safety, please verify and validate this change. arch/x86/mm/init.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index c7a47603537f..5632f02146ca 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -609,7 +609,7 @@ static void __init memory_map_top_down(unsigned long map_start, step_size = PMD_SIZE; max_pfn_mapped = 0; /* will get exact value next */ min_pfn_mapped = real_end >> PAGE_SHIFT; - last_start = start = real_end; + last_start = real_end; /* * We start from the top (end of memory) and go to the bottom. -- 2.17.1