linux-kernel - Re: [PATCH] kbuild: fix kernel/bounds.c 'W=1' warning

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Date:   Fri, 5 Oct 2018 09:47:23 +0100
From:   Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
To:     Arnd Bergmann <arnd@...db.de>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-renesas-soc@...r.kernel.org, stable@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-kbuild@...r.kernel.org,
        yamada.masahiro@...ionext.com
Subject: Re: [PATCH] kbuild: fix kernel/bounds.c 'W=1' warning

Hi Arnd,

On 05/10/18 09:33, Arnd Bergmann wrote:
> Building any configuration with 'make W=1' produces a warning:
> 
> kernel/bounds.c:16:6: warnign: no previous prototype for 'foo' [-Wmissing-prototypes]
> 

s/warnign/warning/ but I don't think that's too important :D

> When also passing -Werror, this prevents us from building any
> other files. Nobody ever calls the function, but we can't make
> it 'static' either since we want the compiler output.
> 
> Calling it 'main' instead however avoids the warning, because gcc
> does not insist on having a declaration for main.

Aha - even better! (and annoyingly fairly obvious, from the
Why-didn't-I-think-of-that department).

> Reported-by: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
> Cc: stable@...r.kernel.org
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>

> ---
> I have run into this problem several times before, and thought I had
> sent a fix at some point. Looking in the archives, I came across
> the suggested fix from Kieran, so I'm following up on that here.
> ---
>  kernel/bounds.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/bounds.c b/kernel/bounds.c
> index c373e887c066..9795d75b09b2 100644
> --- a/kernel/bounds.c
> +++ b/kernel/bounds.c
> @@ -13,7 +13,7 @@
>  #include <linux/log2.h>
>  #include <linux/spinlock_types.h>
>  
> -void foo(void)
> +int main(void)
>  {
>  	/* The enum constants to put into include/generated/bounds.h */
>  	DEFINE(NR_PAGEFLAGS, __NR_PAGEFLAGS);
> @@ -23,4 +23,6 @@ void foo(void)
>  #endif
>  	DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t));
>  	/* End of constants */
> +
> +	return 0;
>  }
>