drm/msm: Ensure get_pages is called when locked

get_pages is only called in a locked context. Add a WARN_ON to make sure
it stays that way.
Signed-off-by: Iskren Chernev <iskren.chernev@gmail.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/msm_gem.c

@@ -96,6 +96,8 @@ static struct page **get_pages(struct drm_gem_object *obj)
 {
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 
+	WARN_ON(!msm_gem_is_locked(obj));
+
 	if (!msm_obj->pages) {
 		struct drm_device *dev = obj->dev;
 		struct page **p;
@@ -1114,8 +1116,9 @@ static struct drm_gem_object *_msm_gem_new(struct drm_device *dev,
 
 		to_msm_bo(obj)->vram_node = &vma->node;
 
-
+		msm_gem_lock(obj);
 		pages = get_pages(obj);
+		msm_gem_unlock(obj);
 		if (IS_ERR(pages)) {
 			ret = PTR_ERR(pages);
 			goto fail;