dma-fence/reservation: Markup rcu protected access for DEBUG_MUTEXES

Mark the access to reservation_object.fence as being protected to
silence sparse.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190612132830.31221-1-chris@chris-wilson.co.uk

diff --git a/include/linux/reservation.h b/include/linux/reservation.h
index ee750765cc9411fcfa84236ac57439520bc81027..644a22dbe53b267fac7ae9bbd91222339781df74 100644 (file)
--- 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);
 }