[PATCH] drm/amdgpu: fix invalid fence handling in amdgpu_vm_tlb_flush

[Lang Yu]

Fixes: 5a1c27951966 ("drm/amdgpu: implement TLB flush fence")

Signed-off-by: Lang Yu <lang.yu at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 1d46a5c81ec4..f93804902fd3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -908,10 +908,12 @@ amdgpu_vm_tlb_flush(struct amdgpu_vm_update_params *params,
 {
 	struct amdgpu_vm *vm = params->vm;
 
-	if (!fence || !*fence)
+	tlb_cb->vm = vm;
+	if (!fence || !*fence) {
+		amdgpu_vm_tlb_seq_cb(NULL, &tlb_cb->cb);
 		return;
+	}
 
-	tlb_cb->vm = vm;
 	if (!dma_fence_add_callback(*fence, &tlb_cb->cb,
 				    amdgpu_vm_tlb_seq_cb)) {
 		dma_fence_put(vm->last_tlb_flush);
-- 
2.25.1