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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Wed, 2 Oct 2019 22:01:51 +0900
Message-ID: <CAK7LNATvGykFY10mOXez84zPV_k3snefgS9zymcn2_7k3EMxAg@mail.gmail.com>
Subject: Re: [PATCH v2] ARM: add __always_inline to functions called from __get_user_check()
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Kate Stewart <kstewart@linuxfoundation.org>,
        Arnd Bergmann <arnd@arndb.de>, Enrico Weigelt <info@metux.net>,
        Vincent Whitchurch <vincent.whitchurch@axis.com>,
        Allison Randal <allison@lohutok.net>,
        Russell King <linux@armlinux.org.uk>,
        Stefan Agner <stefan@agner.ch>,
        LKML <linux-kernel@vger.kernel.org>,
        Russell King <rmk+kernel@armlinux.org.uk>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Olof Johansson <olof@lixom.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Julien Thierry <julien.thierry.kdev@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
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Hi Nick,

On Wed, Oct 2, 2019 at 2:04 AM Nick Desaulniers <ndesaulniers@google.com> wrote:
> > Since that commit, all architectures can enable CONFIG_OPTIMIZE_INLINING.
> > So, __always_inline is now the only guaranteed way of forcible inlining.
>
> No, the C preprocessor is the only guaranteed way of inlining.


I do not think this is fatal if I understood this correctly:
https://lore.kernel.org/patchwork/patch/1122097/#1331784


For GCC, we at least get a warning if a function with
 __always_inline is not inlined.
I am fine with adding -Werror=attributes to the top Makefile
(unless we have unpleasant side-effects).

You filed the bug for Clang, and hopefully it will be OK
in the future releases?


--
Best Regards
Masahiro Yamada