linux-kernel - RE: [PATCH 00/12] Clang -Wformat warning fixes

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Message-ID: <o5496n8r-451p-751-3258-97112opns7s8@vanv.qr>
Date:   Fri, 10 Jun 2022 10:32:13 +0200 (CEST)
From:   Jan Engelhardt <jengelh@...i.de>
To:     David Laight <David.Laight@...LAB.COM>
cc:     'Bill Wendling' <morbo@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Bill Wendling <isanbard@...il.com>,
        Tony Luck <tony.luck@...el.com>,
        Borislav Petkov <bp@...en8.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Phillip Potter <phil@...lpotter.co.uk>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Jan Kara <jack@...e.com>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Jozsef Kadlecsik <kadlec@...filter.org>,
        Florian Westphal <fw@...len.de>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Tom Rix <trix@...hat.com>,
        Ross Philipson <ross.philipson@...cle.com>,
        Daniel Kiper <daniel.kiper@...cle.com>,
        "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "netfilter-devel@...r.kernel.org" <netfilter-devel@...r.kernel.org>,
        "coreteam@...filter.org" <coreteam@...filter.org>,
        Networking <netdev@...r.kernel.org>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        clang-built-linux <llvm@...ts.linux.dev>
Subject: RE: [PATCH 00/12] Clang -Wformat warning fixes


On Friday 2022-06-10 10:17, David Laight wrote:
>> 
>> Calling a "printf" style function is already insanely expensive. :-) I
>> understand that it's not okay blithely to increase runtime resources
>> simply because it's already slow, but in this case it's worthwhile.
>
>Yep, IMHO definitely should be fixed.
>It is even possible that using "%s" is faster because the printf
>code doesn't have to scan the string for format effectors.

I see no special handling; the vsnprintf function just loops
over fmt as usual and I see no special casing of fmt by
e.g. strcmp(fmt, "%s") == 0 to take a shortcut.