virtio_net: bulk free tx skbs

Use napi_consume_skb() to get bulk free.  Note that napi_consume_skb is
safe to call in a non-napi context as long as the napi_budget flag is
correct.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/virtio_net.c

@@ -1330,7 +1330,7 @@ static int virtnet_receive(struct receive_queue *rq, int budget,
 	return stats.packets;
 }
 
-static void free_old_xmit_skbs(struct send_queue *sq)
+static void free_old_xmit_skbs(struct send_queue *sq, bool in_napi)
 {
 	struct sk_buff *skb;
 	unsigned int len;
@@ -1343,7 +1343,7 @@ static void free_old_xmit_skbs(struct send_queue *sq)
 		bytes += skb->len;
 		packets++;
 
-		dev_consume_skb_any(skb);
+		napi_consume_skb(skb, in_napi);
 	}
 
 	/* Avoid overhead when no packets have been processed
@@ -1369,7 +1369,7 @@ static void virtnet_poll_cleantx(struct receive_queue *rq)
 		return;
 
 	if (__netif_tx_trylock(txq)) {
-		free_old_xmit_skbs(sq);
+		free_old_xmit_skbs(sq, true);
 		__netif_tx_unlock(txq);
 	}
 
@@ -1445,7 +1445,7 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
 	struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, vq2txq(sq->vq));
 
 	__netif_tx_lock(txq, raw_smp_processor_id());
-	free_old_xmit_skbs(sq);
+	free_old_xmit_skbs(sq, true);
 	__netif_tx_unlock(txq);
 
 	virtqueue_napi_complete(napi, sq->vq, 0);
@@ -1514,7 +1514,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 	bool use_napi = sq->napi.weight;
 
 	/* Free up any pending old buffers before queueing new ones. */
-	free_old_xmit_skbs(sq);
+	free_old_xmit_skbs(sq, false);
 
 	if (use_napi && kick)
 		virtqueue_enable_cb_delayed(sq->vq);
@@ -1557,7 +1557,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 		if (!use_napi &&
 		    unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
 			/* More just got used, free them then recheck. */
-			free_old_xmit_skbs(sq);
+			free_old_xmit_skbs(sq, false);
 			if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
 				netif_start_subqueue(dev, qnum);
 				virtqueue_disable_cb(sq->vq);