drm/vmwgfx: Make vmw_dmabuf_unreference handle NULL objects

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index 88a179e26de9..7c6f6e3a3c81 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -699,10 +699,13 @@ static inline struct vmw_surface *vmw_surface_reference(struct vmw_surface *srf)
 static inline void vmw_dmabuf_unreference(struct vmw_dma_buffer **buf)
 {
         struct vmw_dma_buffer *tmp_buf = *buf;
-        struct ttm_buffer_object *bo = &tmp_buf->base;
+
         *buf = NULL;
+        if (tmp_buf != NULL) {
+                struct ttm_buffer_object *bo = &tmp_buf->base;
 
-        ttm_bo_unref(&bo);
+                ttm_bo_unref(&bo);
+        }
 }
 
 static inline struct vmw_dma_buffer *vmw_dmabuf_reference(struct vmw_dma_buffer *buf)