[PATCH 5/8] drm/vmwgfx: Make vmw_dmabuf_unreference handle NULL objects

[Thomas Hellstrom]

Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
Reviewed-by: Brian Paul <brianp at vmware.com>
Reviewed-by: Dmitry Torokhov <dtor at vmware.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.h |    7 +++++--
 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 88a179e..7c6f6e3 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)
-- 
1.7.4.4