[PATCH 3/3] drm/amdgpu: fix NULL fence handling in amdgpu_cs_fence_to_handle_ioctl

[Christian König]

When the fence is already signaled it is perfectly normal to get a NULL
fence here. But since we can't export that we need to use a stub fence.

Signed-off-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 024dfbd87f11..fe6bec2075c4 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1421,6 +1421,9 @@ int amdgpu_cs_fence_to_handle_ioctl(struct drm_device *dev, void *data,
 	if (IS_ERR(fence))
 		return PTR_ERR(fence);
 
+	if (!fence)
+		fence = dma_fence_get_stub();
+
 	switch (info->in.what) {
 	case AMDGPU_FENCE_TO_HANDLE_GET_SYNCOBJ:
 		r = drm_syncobj_create(&syncobj, 0, fence);
-- 
2.14.1