drm/virtio: unlock object array on errors

We don't propagate erros to the callers.  We have to unlock object
arrays on errors.
Signed-off-by: NChia-I Wu <olvaffe@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200205181955.202485-6-olvaffe@gmail.comSigned-off-by: NGerd Hoffmann <kraxel@redhat.com>

drivers/gpu/drm/virtio/virtgpu_vq.c

@@ -370,8 +370,11 @@ static void virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev,
 		if (is_vmalloc_addr(vbuf->data_buf)) {
 			sgt = vmalloc_to_sgt(vbuf->data_buf, vbuf->data_size,
 					     &outcnt);
-			if (!sgt)
+			if (!sgt) {
+				if (fence && vbuf->objs)
+					virtio_gpu_array_unlock_resv(vbuf->objs);
 				return;
+			}
 			vout = sgt->sgl;
 		} else {
 			sg_init_one(&sg, vbuf->data_buf, vbuf->data_size);