drm/ttm: add dma_resv_assert_held() calls to vmap/vunmap

Let's make sure nobody is calling those functions without holding the
appropriate locks.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220715111533.467012-2-christian.koenig@amd.com

drivers/gpu/drm/ttm/ttm_bo_util.c

@@ -402,6 +402,8 @@ int ttm_bo_vmap(struct ttm_buffer_object *bo, struct iosys_map *map)
 	struct ttm_resource *mem = bo->resource;
 	int ret;
 
+	dma_resv_assert_held(bo->base.resv);
+
 	ret = ttm_mem_io_reserve(bo->bdev, mem);
 	if (ret)
 		return ret;
@@ -460,6 +462,8 @@ void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct iosys_map *map)
 {
 	struct ttm_resource *mem = bo->resource;
 
+	dma_resv_assert_held(bo->base.resv);
+
 	if (iosys_map_is_null(map))
 		return;