{
struct receive_queue *rq =
container_of(napi, struct receive_queue, napi);
- unsigned int r, received = 0;
+ unsigned int r, received;
- received += virtnet_receive(rq, budget - received);
+ received = virtnet_receive(rq, budget);
/* Out of packets? */
if (received < budget) {
skb_orphan(skb);
nf_reset(skb);
- /* Apparently nice girls don't return TX_BUSY; stop the queue
- * before it gets out of hand. Naturally, this wastes entries. */
+ /* If running out of space, stop queue to avoid getting packets that we
+ * are then unable to transmit.
+ * An alternative would be to force queuing layer to requeue the skb by
+ * returning NETDEV_TX_BUSY. However, NETDEV_TX_BUSY should not be
+ * returned in a normal path of operation: it means that driver is not
+ * maintaining the TX queue stop/start state properly, and causes
+ * the stack to do a non-trivial amount of useless work.
+ * Since most packets only take 1 or 2 ring slots, stopping the queue
+ * early means 16 slots are typically wasted.
+ */
if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
netif_stop_subqueue(dev, qnum);
if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
/* Do we support "hardware" checksums? */
if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
/* This opens up the world of extra features. */
- dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
+ dev->hw_features |= NETIF_F_HW_CSUM | NETIF_F_SG;
if (csum)
- dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
+ dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG;
if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
else
vi->hdr_len = sizeof(struct virtio_net_hdr);
- if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT))
+ if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT) ||
+ virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
vi->any_header_sg = true;
if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))