drm/amdgpu: add missing lock in amdgpu_benchmark_do_move

Taking the entity lock is required to guarantee the ordering of
execution. The next commit will add a check that the lock is
held.

Signed-off-by: Pierre-Eric Pelloux-Prayer <[email protected]>
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

drivers/gpu/drm/amd/amdgpu/amdgpu_benchmark.c

@@ -35,6 +35,7 @@ static int amdgpu_benchmark_do_move(struct amdgpu_device *adev, unsigned size,
 	struct dma_fence *fence;
 	int i, r;
 
+	mutex_lock(&adev->mman.default_entity.lock);
 	stime = ktime_get();
 	for (i = 0; i < n; i++) {
 		r = amdgpu_copy_buffer(adev, &adev->mman.default_entity,
@@ -47,6 +48,7 @@ static int amdgpu_benchmark_do_move(struct amdgpu_device *adev, unsigned size,
 		if (r)
 			goto exit_do_move;
 	}
+	mutex_unlock(&adev->mman.default_entity.lock);
 
 exit_do_move:
 	etime = ktime_get();