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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 6 Jun 2017 14:28:03 -0700
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Subject: Re: [RFC] clang: 'unused-function' warning on static inline functions
To: Matthias Kaehlcke <mka@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ingo Molnar <mingo@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
        Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        Steven Rostedt <rostedt@goodmis.org>,
        David Rientjes <rientjes@google.com>,
        Douglas Anderson <dianders@chromium.org>,
        Guenter Roeck <linux@roeck-us.net>, Mark Brown <broonie@kernel.org>,
        David Miller <davem@davemloft.net>
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On Tue, Jun 6, 2017 at 2:23 PM, Matthias Kaehlcke <mka@chromium.org> wrote:
>
> I tend to disagree, the warning is useful to detect truly unused
> static inline functions, which should be removed, rather than be
> carried around/maintained for often long periods of time.

That may be true in other projects, but we really do have a lot of
code that is conditionally used. The warning is just not useful.

I agree that we could use "__maybe_unused", but at the same time, I
don't really see the point. There's no way in hell we'd ever do that
for inlines that are in header files (*of course* they may be unused),
why would we then haev a magical rule like "let's do it for inlines in
C files".

I applied the patch from David Rientjes to just make "inline"
automatically mean "maybe unused" for clang.

                    Linus