drm/shmem-helper: Add lockdep asserts to vmap/vunmap

Since commit 21aa27d ("drm/shmem-helper: Switch to reservation
lock"), the drm_gem_shmem_vmap and drm_gem_shmem_vunmap functions
require that the caller holds the DMA reservation lock for the object.
Add lockdep assertions to help validate this.

Signed-off-by: Asahi Lina <[email protected]>

Author: hoshinolina

drivers/gpu/drm/drm_gem_shmem_helper.c

@@ -313,6 +313,8 @@ int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem,
 	struct drm_gem_object *obj = &shmem->base;
 	int ret = 0;
 
+	dma_resv_assert_held(obj->resv);
+
 	if (obj->import_attach) {
 		ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
 		if (!ret) {
@@ -379,6 +381,8 @@ void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem,
 {
 	struct drm_gem_object *obj = &shmem->base;
 
+	dma_resv_assert_held(obj->resv);
+
 	if (obj->import_attach) {
 		dma_buf_vunmap(obj->import_attach->dmabuf, map);
 	} else {