Re: h8300 build failures in linux-next (in rcu code, gcc 5.x related, not limited to h8300)

[Mark Salter <msalter@redhat.com>]

On Tue, 2015-08-25 at 20:02 +0200, Oleg Nesterov wrote:
> On 08/25, Oleg Nesterov wrote:
> > 
> > On 08/26, Yoshinori Sato wrote:
> > > 
> > > Yes.
> > > gcc bug #67055.
> > > Already fixed in trunk.
> > 
> > Yes, thanks a lot.
> > 
> > Paul, it seems that gcc actually dislikes your ec90a194a "rcu:
> > Create a synchronize_rcu_mult()" commit ;) rcu/sync.c was just
> > lucky enough to trigger the problem.
> > 
> > I'll try to make the fix today...
> 
> Mark, Guenter, any chance you can check if the patch below helps?
> It does on x86.

Works for c6x.

> 
> Oleg.
> 
> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@ -230,12 +230,11 @@ void __wait_rcu_gp(bool checktiny, int n, 
> call_rcu_func_t *crcu_array,
>  		   struct rcu_synchronize *rs_array);
>  
>  #define _wait_rcu_gp(checktiny, ...) \
> -do { \
> -	call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
> -	const int __n = ARRAY_SIZE(__crcu_array); \
> -	struct rcu_synchronize __rs_array[__n]; \
> -	\
> -	__wait_rcu_gp(checktiny, __n, __crcu_array, __rs_array); \
> +do {									
> \
> +	call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; 		
> \
> +	struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)];	
> \
> +	__wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array),		
> \
> +			__crcu_array, __rs_array); 			
> \
>  } while (0)
>  
>  #define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)
>