virtio-gpu: add locking for vbuf pool

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index ff8de3d..6d4db2db 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -162,6 +162,7 @@
 	struct virtio_gpu_queue ctrlq;
 	struct virtio_gpu_queue cursorq;
 	struct list_head free_vbufs;
+	spinlock_t free_vbufs_lock;
 	void *vbufs;
 	bool vqs_ready;