drm/scheduler: implement a function to modify sched list

Implement drm_sched_entity_modify_sched() which modifies existing
sched_list with a different one. This is going to be helpful when
userspace changes priority of a ctx/entity then the driver can switch
to the corresponding HW scheduler list for that priority.

Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/scheduler/sched_entity.c

@@ -83,6 +83,24 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
 }
 EXPORT_SYMBOL(drm_sched_entity_init);
 
+/**
+ * drm_sched_entity_modify_sched - Modify sched of an entity
+ * @entity: scheduler entity to init
+ * @sched_list: the list of new drm scheds which will replace
+ *		 existing entity->sched_list
+ * @num_sched_list: number of drm sched in sched_list
+ */
+void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
+				    struct drm_gpu_scheduler **sched_list,
+				    unsigned int num_sched_list)
+{
+	WARN_ON(!num_sched_list || !sched_list);
+
+	entity->sched_list = sched_list;
+	entity->num_sched_list = num_sched_list;
+}
+EXPORT_SYMBOL(drm_sched_entity_modify_sched);
+
 /**
  * drm_sched_entity_is_idle - Check if entity is idle
  *