[CRIU] [PATCH 1/2] compiler: Add comment about is_log2 helper

[Pavel Emelyanov]

On 12/10/2012 06:07 PM, Cyrill Gorcunov wrote:
> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
> ---
>  include/compiler.h | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/include/compiler.h b/include/compiler.h
> index 621cedb..fd8fd2f 100644
> --- a/include/compiler.h
> +++ b/include/compiler.h
> @@ -66,6 +66,10 @@
>  	(void) (&_max1 == &_max2);		\
>  	_max1 > _max2 ? _max1 : _max2; })
>  
> -#define is_log2(v)		(((v) & ((v) - 1)) == 0)
> +/*
> + * Note the side effects here: if v = [0;1] it will
> + * return true for obvious reason
> + */
> +#define is_log2(v)             (((v) & ((v) - 1)) == 0)

So fix IT to report result properly, not callers. If you care
about having "pure" is_log2, then rename this one into __is_log2,
and make the is_log2 do proper checks.

>  #endif /* CR_COMPILER_H_ */
>