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From:   Arnd Bergmann <arnd@kernel.org>
Date:   Mon, 28 Feb 2022 19:24:54 +0100
Message-ID: <CAK8P3a2To9St5=v6EHtJ-LBEp4-NOThPmO+qYeAfnxQPm2_Keg@mail.gmail.com>
Subject: Re: [PATCH] [v2] Kbuild: move to -std=gnu11
To:     Masahiro Yamada <masahiroy@kernel.org>,
        Jani Nikula <jani.nikula@linux.intel.com>
Cc:     Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        llvm@lists.linux.dev, Jonathan Corbet <corbet@lwn.net>,
        Federico Vaga <federico.vaga@vaga.pv.it>,
        Alex Shi <alexs@kernel.org>, Hu Haowen <src.res@email.cn>,
        Michal Marek <michal.lkml@markovi.net>,
        Nick Desaulniers <ndesaulniers@google.com>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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        intel-gfx <intel-gfx@lists.freedesktop.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        greybus-dev@lists.linaro.org, linux-staging@lists.linux.dev,
        linux-btrfs <linux-btrfs@vger.kernel.org>
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On Mon, Feb 28, 2022 at 6:02 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> On Mon, Feb 28, 2022 at 7:32 PM Arnd Bergmann <arnd@kernel.org> wrote:
> >
> > From: Arnd Bergmann <arnd@arndb.de>
> >
> > During a patch discussion, Linus brought up the option of changing
> > the C standard version from gnu89 to gnu99, which allows using variable
> > declaration inside of a for() loop. While the C99, C11 and later standards
> > introduce many other features, most of these are already available in
> > gnu89 as GNU extensions as well.
> >
> > An earlier attempt to do this when gcc-5 started defaulting to
> > -std=gnu11 failed because at the time that caused warnings about
> > designated initializers with older compilers. Now that gcc-5.1 is the
> > minimum compiler version used for building kernels, that is no longer a
> > concern. Similarly, the behavior of 'inline' functions changes between
> > gnu89 and gnu11, but this was taken care of by defining 'inline' to
> > include __attribute__((gnu_inline)) in order to allow building with
> > clang a while ago.
> >
> > One minor issue that remains is an added gcc warning for shifts of
> > negative integers when building with -Werror, which happens with the
>
> Is this a typo?
>
>    building with -Werror, ...
> ->
>    building with -Wextra, ...
>

I'm being slow today, Jani actually pointed out the same thing and I
misunderstood him. Fixed it now, thanks!

> Acked-by: Masahiro Yamada <masahiroy@kernel.org>
>
>
> Please let me know if you want me to pick up this.

Yes, that would be great. I'll send a v3 with the updated changelog,
but will drop most of the Cc list as there are no functional changes.

        Arnd