virtio: finer-grained features for virtio_net

[linux-2.6-omap-h63xx.git] / drivers / net / virtio_net.c

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 555b70c8b8635226a1fa295c7334d5d70c34f939..ad43421ab6f1cf49d0335df7b9ea6cb8f365285b 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -41,6 +41,9 @@ 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;
+
        /* Number of input buffers, and max we've ever had. */
        unsigned int num, max;
 
@@ -142,10 +145,10 @@ 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 +224,22 @@ 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)
+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];
+       int num;
+       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 +274,51 @@ 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);
+
+       return vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
+}
+
+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 (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);
+                       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 */
+       __skb_queue_head(&vi->send, skb);
+       if (xmit_skb(vi, skb) != 0) {
+               vi->last_xmit_skb = skb;
+               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
@@ -362,6 +385,15 @@ static int virtnet_probe(struct virtio_device *vdev)
                        dev->features |= NETIF_F_TSO | NETIF_F_UFO
                                | NETIF_F_TSO_ECN | NETIF_F_TSO6;
                }
+               /* Individual feature bits: what can host handle? */
+               if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_HOST_TSO4))
+                       dev->features |= NETIF_F_TSO;
+               if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_HOST_TSO6))
+                       dev->features |= NETIF_F_TSO6;
+               if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_HOST_ECN))
+                       dev->features |= NETIF_F_TSO_ECN;
+               if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_HOST_UFO))
+                       dev->features |= NETIF_F_UFO;
        }
 
        /* Configuration may specify what MAC to use.  Otherwise random. */