[Intel-gfx] [PATCH] dma-fence/reservation: Markup rcu protected access for DEBUG_MUTEXES

[Christian König]

Am 12.06.19 um 15:28 schrieb Chris Wilson:
> Mark the access to reservation_object.fence as being protected to
> silence sparse.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Reviewed-by: Christian König <christian.koenig at amd.com>

> ---
>   include/linux/reservation.h | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/reservation.h b/include/linux/reservation.h
> index ee750765cc94..644a22dbe53b 100644
> --- a/include/linux/reservation.h
> +++ b/include/linux/reservation.h
> @@ -216,8 +216,12 @@ reservation_object_unlock(struct reservation_object *obj)
>   {
>   #ifdef CONFIG_DEBUG_MUTEXES
>   	/* Test shared fence slot reservation */
> -	if (obj->fence)
> -		obj->fence->shared_max = obj->fence->shared_count;
> +	if (rcu_access_pointer(obj->fence)) {
> +		struct reservation_object_list *fence =
> +			reservation_object_get_list(obj);
> +
> +		fence->shared_max = fence->shared_count;
> +	}
>   #endif
>   	ww_mutex_unlock(&obj->lock);
>   }