drm/prime: fix sgt NULL checking

The drm_gem_map_detach() can be called with sgt is NULL.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 1e0de41f085c..ff5fecef367b 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -119,12 +119,13 @@ static void drm_gem_map_detach(struct dma_buf *dma_buf,
                 return;
 
         sgt = prime_attach->sgt;
+        if (sgt) {
+                if (prime_attach->dir != DMA_NONE)
+                        dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
+                                        prime_attach->dir);
+                sg_free_table(sgt);
+        }
 
-        if (prime_attach->dir != DMA_NONE)
-                dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
-                                prime_attach->dir);
-
-        sg_free_table(sgt);
         kfree(sgt);
         kfree(prime_attach);
         attach->priv = NULL;