1 files changed, 136 insertions, 33 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 555b70c8b86..4452306d532 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -41,9 +41,19 @@ struct virtnet_info
 	struct net_device *dev;
 	struct napi_struct napi;
 
+	/* The skb we couldn't send because buffers were full. */
+	struct sk_buff *last_xmit_skb;
+
+	/* If we need to free in a timer, this is it. */
+	struct timer_list xmit_free_timer;
+
 	/* Number of input buffers, and max we've ever had. */
 	unsigned int num, max;
 
+	/* For cleaning up after transmission. */
+	struct tasklet_struct tasklet;
+	bool free_in_tasklet;
+
 	/* Receive & send queues. */
 	struct sk_buff_head recv;
 	struct sk_buff_head send;
@@ -65,8 +75,13 @@ static void skb_xmit_done(struct virtqueue *svq)
 
 	/* Suppress further interrupts. */
 	svq->vq_ops->disable_cb(svq);
-	/* We were waiting for more output buffers. */
+
+	/* We were probably waiting for more output buffers. */
 	netif_wake_queue(vi->dev);
+
+	/* Make sure we re-xmit last_xmit_skb: if there are no more packets
+	 * queued, start_xmit won't be called. */
+	tasklet_schedule(&vi->tasklet);
 }
 
 static void receive_skb(struct net_device *dev, struct sk_buff *skb,
@@ -83,9 +98,7 @@ static void receive_skb(struct net_device *dev, struct sk_buff *skb,
 	BUG_ON(len > MAX_PACKET_LEN);
 
 	skb_trim(skb, len);
-	skb->protocol = eth_type_trans(skb, dev);
-	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
-		 ntohs(skb->protocol), skb->len, skb->pkt_type);
+
 	dev->stats.rx_bytes += skb->len;
 	dev->stats.rx_packets++;
 
@@ -95,6 +108,10 @@ static void receive_skb(struct net_device *dev, struct sk_buff *skb,
 			goto frame_err;
 	}
 
+	skb->protocol = eth_type_trans(skb, dev);
+	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
+		 ntohs(skb->protocol), skb->len, skb->pkt_type);
+
 	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 		pr_debug("GSO!\n");
 		switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
@@ -142,10 +159,10 @@ drop:
 static void try_fill_recv(struct virtnet_info *vi)
 {
 	struct sk_buff *skb;
-	struct scatterlist sg[1+MAX_SKB_FRAGS];
+	struct scatterlist sg[2+MAX_SKB_FRAGS];
 	int num, err;
 
-	sg_init_table(sg, 1+MAX_SKB_FRAGS);
+	sg_init_table(sg, 2+MAX_SKB_FRAGS);
 	for (;;) {
 		skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
 		if (unlikely(!skb))
@@ -221,23 +238,38 @@ static void free_old_xmit_skbs(struct virtnet_info *vi)
 	while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
 		pr_debug("Sent skb %p\n", skb);
 		__skb_unlink(skb, &vi->send);
-		vi->dev->stats.tx_bytes += len;
+		vi->dev->stats.tx_bytes += skb->len;
 		vi->dev->stats.tx_packets++;
 		kfree_skb(skb);
 	}
 }
 
-static int start_xmit(struct sk_buff *skb, struct net_device *dev)
+/* If the virtio transport doesn't always notify us when all in-flight packets
+ * are consumed, we fall back to using this function on a timer to free them. */
+static void xmit_free(unsigned long data)
+{
+	struct virtnet_info *vi = (void *)data;
+
+	netif_tx_lock(vi->dev);
+
+	free_old_xmit_skbs(vi);
+
+	if (!skb_queue_empty(&vi->send))
+		mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
+
+	netif_tx_unlock(vi->dev);
+}
+
+static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
 {
-	struct virtnet_info *vi = netdev_priv(dev);
 	int num, err;
-	struct scatterlist sg[1+MAX_SKB_FRAGS];
+	struct scatterlist sg[2+MAX_SKB_FRAGS];
 	struct virtio_net_hdr *hdr;
 	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 
-	sg_init_table(sg, 1+MAX_SKB_FRAGS);
+	sg_init_table(sg, 2+MAX_SKB_FRAGS);
 
-	pr_debug("%s: xmit %p " MAC_FMT "\n", dev->name, skb,
+	pr_debug("%s: xmit %p " MAC_FMT "\n", vi->dev->name, skb,
 		 dest[0], dest[1], dest[2],
 		 dest[3], dest[4], dest[5]);
 
@@ -272,30 +304,73 @@ static int start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	vnet_hdr_to_sg(sg, skb);
 	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
-	__skb_queue_head(&vi->send, skb);
+
+	err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
+	if (!err && !vi->free_in_tasklet)
+		mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
+
+	return err;
+}
+
+static void xmit_tasklet(unsigned long data)
+{
+	struct virtnet_info *vi = (void *)data;
+
+	netif_tx_lock_bh(vi->dev);
+	if (vi->last_xmit_skb && xmit_skb(vi, vi->last_xmit_skb) == 0) {
+		vi->svq->vq_ops->kick(vi->svq);
+		vi->last_xmit_skb = NULL;
+	}
+	if (vi->free_in_tasklet)
+		free_old_xmit_skbs(vi);
+	netif_tx_unlock_bh(vi->dev);
+}
+
+static int start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
 
 again:
 	/* Free up any pending old buffers before queueing new ones. */
 	free_old_xmit_skbs(vi);
-	err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
-	if (err) {
-		pr_debug("%s: virtio not prepared to send\n", dev->name);
-		netif_stop_queue(dev);
-
-		/* Activate callback for using skbs: if this returns false it
-		 * means some were used in the meantime. */
-		if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
-			vi->svq->vq_ops->disable_cb(vi->svq);
-			netif_start_queue(dev);
-			goto again;
+
+	/* If we has a buffer left over from last time, send it now. */
+	if (unlikely(vi->last_xmit_skb)) {
+		if (xmit_skb(vi, vi->last_xmit_skb) != 0) {
+			/* Drop this skb: we only queue one. */
+			vi->dev->stats.tx_dropped++;
+			kfree_skb(skb);
+			skb = NULL;
+			goto stop_queue;
 		}
-		__skb_unlink(skb, &vi->send);
+		vi->last_xmit_skb = NULL;
+	}
 
-		return NETDEV_TX_BUSY;
+	/* Put new one in send queue and do transmit */
+	if (likely(skb)) {
+		__skb_queue_head(&vi->send, skb);
+		if (xmit_skb(vi, skb) != 0) {
+			vi->last_xmit_skb = skb;
+			skb = NULL;
+			goto stop_queue;
+		}
 	}
+done:
 	vi->svq->vq_ops->kick(vi->svq);
-
-	return 0;
+	return NETDEV_TX_OK;
+
+stop_queue:
+	pr_debug("%s: virtio not prepared to send\n", dev->name);
+	netif_stop_queue(dev);
+
+	/* Activate callback for using skbs: if this returns false it
+	 * means some were used in the meantime. */
+	if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
+		vi->svq->vq_ops->disable_cb(vi->svq);
+		netif_start_queue(dev);
+		goto again;
+	}
+	goto done;
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
@@ -355,17 +430,26 @@ static int virtnet_probe(struct virtio_device *vdev)
 	SET_NETDEV_DEV(dev, &vdev->dev);
 
 	/* Do we support "hardware" checksums? */
-	if (csum && vdev->config->feature(vdev, VIRTIO_NET_F_CSUM)) {
+	if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
 		/* This opens up the world of extra features. */
 		dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
-		if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_GSO)) {
+		if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
 			dev->features |= NETIF_F_TSO | NETIF_F_UFO
 				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
 		}
+		/* Individual feature bits: what can host handle? */
+		if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
+			dev->features |= NETIF_F_TSO;
+		if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
+			dev->features |= NETIF_F_TSO6;
+		if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
+			dev->features |= NETIF_F_TSO_ECN;
+		if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
+			dev->features |= NETIF_F_UFO;
 	}
 
 	/* Configuration may specify what MAC to use.  Otherwise random. */
-	if (vdev->config->feature(vdev, VIRTIO_NET_F_MAC)) {
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 		vdev->config->get(vdev,
 				  offsetof(struct virtio_net_config, mac),
 				  dev->dev_addr, dev->addr_len);
@@ -379,6 +463,10 @@ static int virtnet_probe(struct virtio_device *vdev)
 	vi->vdev = vdev;
 	vdev->priv = vi;
 
+	/* If they give us a callback when all buffers are done, we don't need
+	 * the timer. */
+	vi->free_in_tasklet = virtio_has_feature(vdev,VIRTIO_F_NOTIFY_ON_EMPTY);
+
 	/* We expect two virtqueues, receive then send. */
 	vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
 	if (IS_ERR(vi->rvq)) {
@@ -396,6 +484,11 @@ static int virtnet_probe(struct virtio_device *vdev)
 	skb_queue_head_init(&vi->recv);
 	skb_queue_head_init(&vi->send);
 
+	tasklet_init(&vi->tasklet, xmit_tasklet, (unsigned long)vi);
+
+	if (!vi->free_in_tasklet)
+		setup_timer(&vi->xmit_free_timer, xmit_free, (unsigned long)vi);
+
 	err = register_netdev(dev);
 	if (err) {
 		pr_debug("virtio_net: registering device failed\n");
@@ -433,13 +526,15 @@ static void virtnet_remove(struct virtio_device *vdev)
 	/* Stop all the virtqueues. */
 	vdev->config->reset(vdev);
 
+	if (!vi->free_in_tasklet)
+		del_timer_sync(&vi->xmit_free_timer);
+
 	/* Free our skbs in send and recv queues, if any. */
 	while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
 		kfree_skb(skb);
 		vi->num--;
 	}
-	while ((skb = __skb_dequeue(&vi->send)) != NULL)
-		kfree_skb(skb);
+	__skb_queue_purge(&vi->send);
 
 	BUG_ON(vi->num != 0);
 
@@ -454,7 +549,15 @@ static struct virtio_device_id id_table[] = {
 	{ 0 },
 };
 
+static unsigned int features[] = {
+	VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
+	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
+	VIRTIO_NET_F_HOST_ECN, VIRTIO_F_NOTIFY_ON_EMPTY,
+};
+
 static struct virtio_driver virtio_net = {
+	.feature_table = features,
+	.feature_table_size = ARRAY_SIZE(features),
 	.driver.name =	KBUILD_MODNAME,
 	.driver.owner =	THIS_MODULE,
 	.id_table =	id_table,