+#ifdef CONFIG_NET_RX_BUSY_POLL
+/* must be called with local_bh_disable()d */
+static int virtnet_busy_poll(struct napi_struct *napi)
+{
+ struct receive_queue *rq =
+ container_of(napi, struct receive_queue, napi);
+ struct virtnet_info *vi = rq->vq->vdev->priv;
+ int r, received = 0, budget = 4;
+
+ if (!(vi->status & VIRTIO_NET_S_LINK_UP))
+ return LL_FLUSH_FAILED;
+
+ if (!napi_schedule_prep(napi))
+ return LL_FLUSH_BUSY;
+
+ virtqueue_disable_cb(rq->vq);
+
+again:
+ received += virtnet_receive(rq, budget);
+
+ r = virtqueue_enable_cb_prepare(rq->vq);
+ clear_bit(NAPI_STATE_SCHED, &napi->state);
+ if (unlikely(virtqueue_poll(rq->vq, r)) &&
+ napi_schedule_prep(napi)) {
+ virtqueue_disable_cb(rq->vq);
+ if (received < budget) {
+ budget -= received;
+ goto again;
+ } else {
+ __napi_schedule(napi);
+ }
+ }
+
+ return received;
+}
+#endif /* CONFIG_NET_RX_BUSY_POLL */
+