Merge branch 'iocb' into for-davem

[deliverable/linux.git] / drivers / net / virtio_net.c

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index f1ff3666f090d886e6b8ecc99bc6ac09d8687ef6..63c7810e1545a357eda7578af862ed18322de933 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -749,9 +749,9 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
 {
        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) {
@@ -939,8 +939,16 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
        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))) {
@@ -1448,8 +1456,10 @@ static void virtnet_free_queues(struct virtnet_info *vi)
 {
        int i;
 
-       for (i = 0; i < vi->max_queue_pairs; i++)
+       for (i = 0; i < vi->max_queue_pairs; i++) {
+               napi_hash_del(&vi->rq[i].napi);
                netif_napi_del(&vi->rq[i].napi);
+       }
 
        kfree(vi->rq);
        kfree(vi->sq);
@@ -1948,11 +1958,8 @@ static int virtnet_freeze(struct virtio_device *vdev)
        cancel_delayed_work_sync(&vi->refill);
 
        if (netif_running(vi->dev)) {
-               for (i = 0; i < vi->max_queue_pairs; i++) {
+               for (i = 0; i < vi->max_queue_pairs; i++)
                        napi_disable(&vi->rq[i].napi);
-                       napi_hash_del(&vi->rq[i].napi);
-                       netif_napi_del(&vi->rq[i].napi);
-               }
        }
 
        remove_vq_common(vi);