drm/virtio: drop virtio_gpu_fence_cleanup()

Just call drm_fence_put directly instead.
Also set vgfb->fence to NULL after dropping the reference.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Ezequiel Garcia <ezequiel@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20181219122708.4586-4-kraxel@redhat.com

drivers/gpu/drm/virtio/virtgpu_drv.h

@@ -337,7 +337,6 @@ int virtio_gpu_mmap(struct file *filp, struct vm_area_struct *vma);
 /* virtio_gpu_fence.c */
 struct virtio_gpu_fence *virtio_gpu_fence_alloc(
 	struct virtio_gpu_device *vgdev);
-void virtio_gpu_fence_cleanup(struct virtio_gpu_fence *fence);
 int virtio_gpu_fence_emit(struct virtio_gpu_device *vgdev,
 			  struct virtio_gpu_ctrl_hdr *cmd_hdr,
 			  struct virtio_gpu_fence *fence);

drivers/gpu/drm/virtio/virtgpu_fence.c

@@ -81,14 +81,6 @@ struct virtio_gpu_fence *virtio_gpu_fence_alloc(struct virtio_gpu_device *vgdev)
 	return fence;
 }
 
-void virtio_gpu_fence_cleanup(struct virtio_gpu_fence *fence)
-{
-	if (!fence)
-		return;
-
-	dma_fence_put(&fence->f);
-}
-
 int virtio_gpu_fence_emit(struct virtio_gpu_device *vgdev,
 			  struct virtio_gpu_ctrl_hdr *cmd_hdr,
 			  struct virtio_gpu_fence *fence)

drivers/gpu/drm/virtio/virtgpu_ioctl.c

@@ -351,7 +351,7 @@ static int virtio_gpu_resource_create_ioctl(struct drm_device *dev, void *data,
 		virtio_gpu_cmd_resource_create_3d(vgdev, qobj, &rc_3d);
 		ret = virtio_gpu_object_attach(vgdev, qobj, fence);
 		if (ret) {
-			virtio_gpu_fence_cleanup(fence);
+			dma_fence_put(&fence->f);
 			goto fail_backoff;
 		}
 		ttm_eu_fence_buffer_objects(&ticket, &validate_list, &fence->f);

drivers/gpu/drm/virtio/virtgpu_plane.c

@@ -169,8 +169,10 @@ static void virtio_gpu_cursor_cleanup_fb(struct drm_plane *plane,
 		return;
 
 	vgfb = to_virtio_gpu_framebuffer(plane->state->fb);
-	if (vgfb->fence)
-		virtio_gpu_fence_cleanup(vgfb->fence);
+	if (vgfb->fence) {
+		dma_fence_put(&vgfb->fence->f);
+		vgfb->fence = NULL;
+	}
 }
 
 static void virtio_gpu_cursor_plane_update(struct drm_plane *plane,