From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f67.google.com (mail-ed1-f67.google.com [209.85.208.67]) by mx.groups.io with SMTP id smtpd.web10.33050.1601287215459371617 for ; Mon, 28 Sep 2020 03:00:15 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@gmail.com header.s=20161025 header.b=R+pfU0To; spf=pass (domain: gmail.com, ip: 209.85.208.67, mailfrom: lukas.bulwahn@gmail.com) Received: by mail-ed1-f67.google.com with SMTP id i1so640443edv.2 for ; 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=BJZKXzWTiy7P4FMvZ1VFwF+t8IuIH7yCv/P8QwXoFm5aZ7x6H2m4M7ZoleOpKkSEDA oZ1obNaJVFahznMGtUrni6R5rVmOsS1kIGvYR/AYNInWnFud0cnvKZyvIuXBhMCPrfkp EiLYmps8c1SP5ws9YK5KRFI/+n/AWamGyhjNXrtznGNPAJhYgm/ckn2FMvPZ0bVGMqbU /nyJoB/dyVjK9a6/sgGKrc1bOZHx1+sIGCp3GrCfLbzb/8zMktOFc/Oy7SGDdlqn92zn rVmnjtZlbmSXyImRJ3zsY32P0g/r+I9Qo7QbibQsS/AAkl98rwc3FVssbqir889Dp/f2 vgaw== X-Gm-Message-State: AOAM532wM1ia+lFmJa33h/QMEgPSzki6xATcsReXsjS2khexjzC4o2m4 6LTrfiSde4mG/eBHub+smOE= 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) Return-Path: 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 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