Re: [PATCH] rculist: Silence unused-value warning.

From: Paul E. McKenney
Date: Sun Jul 19 2020 - 12:07:49 EST


On Sun, Jul 19, 2020 at 04:20:37PM +0530, Suraj Upadhyay wrote:
> The macro __list_check_srcu is used as a statement inside a for loop.
>
> __list_check_srcu becomes "true" when CONFIG_PROVE_RCU_LIST is not defined.
> This results in compiler warning about an unused value ("true").
>
> Silence the compiler warning about the unused value "true"
> by replacing it with an empty expression.
>
> Signed-off-by: Suraj Upadhyay <usuraj35@xxxxxxxxx>

Like this, you mean, give or take whitespace? ;-)

20200718001259.GY9247@paulmck-ThinkPad-P72/">https://lore.kernel.org/lkml/20200718001259.GY9247@paulmck-ThinkPad-P72/

May I add your Tested-by?

Thanx, Paul

> ---
> include/linux/rculist.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/rculist.h b/include/linux/rculist.h
> index de9385b9158e..8b8e0584c473 100644
> --- a/include/linux/rculist.h
> +++ b/include/linux/rculist.h
> @@ -73,7 +73,7 @@ static inline void INIT_LIST_HEAD_RCU(struct list_head *list)
> #define __list_check_rcu(dummy, cond, extra...) \
> ({ check_arg_count_one(extra); })
>
> -#define __list_check_srcu(cond) true
> +#define __list_check_srcu(cond) ({})
> #endif
>
> /*
> --
> 2.17.1
>