Re: [PATCH] debugobjects: avoid another unused variable warning.

[Yang Shi]

On 3/13/18 6:18 AM, Arnd Bergmann wrote:
> debug_objects_maxchecked is only updated in __debug_check_no_obj_freed(),
> and only read in debug_objects_maxchecked, unfortunately both of
> these are optional and depend on different Kconfig symbols. When both
> CONFIG_DEBUG_OBJECTS_FREE and CONFIG_DEBUG_FS are disabled, we get
> this warning:
>
> lib/debugobjects.c:56:14: error: 'debug_objects_maxchecked' defined but not used [-Werror=unused-variable]
>
> Rather than trying to add more complex #ifdef protections, this marks
> the variable as __maybe_unused so it can be silently dropped when
> usused.

Thanks for catching this.

Acked-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>

> Fixes: bd9dcd046509 ("debugobjects: Export max loops counter")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
>   lib/debugobjects.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/debugobjects.c b/lib/debugobjects.c
> index 105ecfc47d8c..994be4805cec 100644
> --- a/lib/debugobjects.c
> +++ b/lib/debugobjects.c
> @@ -53,7 +53,7 @@ static int			obj_nr_tofree;
>   static struct kmem_cache	*obj_cache;
>   
>   static int			debug_objects_maxchain __read_mostly;
> -static int			debug_objects_maxchecked __read_mostly;
> +static int __maybe_unused	debug_objects_maxchecked __read_mostly;
>   static int			debug_objects_fixups __read_mostly;
>   static int			debug_objects_warnings __read_mostly;
>   static int			debug_objects_enabled __read_mostly