virtio_net: remove send queue

Now we have a virtio detach API (in commit
f9bfbebf34eab707b065116cdc9699d25ba4252a), we don't need to track xmit
skbs in the virio_net driver, which improves transmission performance.

Signed-off-by: Shirley Ma <xma@us.ibm.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 4c347a3..ce35b42 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -56,9 +56,6 @@ struct virtnet_info
        /* Host will merge rx buffers for big packets (shake it! shake it!) */
        bool mergeable_rx_bufs;
 
        /* Host will merge rx buffers for big packets (shake it! shake it!) */
        bool mergeable_rx_bufs;
 

-       /* Send queue. */
-       struct sk_buff_head send;
-

        /* Work struct for refilling if we run low on memory. */
        struct delayed_work refill;
 
        /* Work struct for refilling if we run low on memory. */
        struct delayed_work refill;
 


@@ -505,7 +502,6 @@ static unsigned int 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);
 
        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 += skb->len;
                vi->dev->stats.tx_packets++;
                tot_sgs += skb_vnet_hdr(skb)->num_sg;
                vi->dev->stats.tx_bytes += skb->len;
                vi->dev->stats.tx_packets++;
                tot_sgs += skb_vnet_hdr(skb)->num_sg;


@@ -588,15 +584,6 @@ again:
        }
        vi->svq->vq_ops->kick(vi->svq);
 
        }
        vi->svq->vq_ops->kick(vi->svq);
 

-       /*
-        * Put new one in send queue.  You'd expect we'd need this before
-        * xmit_skb calls add_buf(), since the callback can be triggered
-        * immediately after that.  But since the callback just triggers
-        * another call back here, normal network xmit locking prevents the
-        * race.
-        */
-       __skb_queue_head(&vi->send, skb);
-

        /* Don't wait up for transmitted skbs to be freed. */
        skb_orphan(skb);
        nf_reset(skb);
        /* Don't wait up for transmitted skbs to be freed. */
        skb_orphan(skb);
        nf_reset(skb);


@@ -980,9 +967,6 @@ static int virtnet_probe(struct virtio_device *vdev)
                        dev->features |= NETIF_F_HW_VLAN_FILTER;
        }
 
                        dev->features |= NETIF_F_HW_VLAN_FILTER;
        }
 

-       /* Initialize our empty send queue. */
-       skb_queue_head_init(&vi->send);
-

        err = register_netdev(dev);
        if (err) {
                pr_debug("virtio_net: registering device failed\n");
        err = register_netdev(dev);
        if (err) {
                pr_debug("virtio_net: registering device failed\n");


@@ -1019,6 +1003,12 @@ static void free_unused_bufs(struct virtnet_info *vi)
 {
        void *buf;
        while (1) {
 {
        void *buf;
        while (1) {

+               buf = vi->svq->vq_ops->detach_unused_buf(vi->svq);
+               if (!buf)
+                       break;
+               dev_kfree_skb(buf);
+       }
+       while (1) {

                buf = vi->rvq->vq_ops->detach_unused_buf(vi->rvq);
                if (!buf)
                        break;
                buf = vi->rvq->vq_ops->detach_unused_buf(vi->rvq);
                if (!buf)
                        break;


@@ -1038,11 +1028,11 @@ static void __devexit virtnet_remove(struct virtio_device *vdev)
        /* Stop all the virtqueues. */
        vdev->config->reset(vdev);
 
        /* Stop all the virtqueues. */
        vdev->config->reset(vdev);
 

-       /* Free our skbs in send queue, if any. */
-       __skb_queue_purge(&vi->send);

 
        unregister_netdev(vi->dev);
        cancel_delayed_work_sync(&vi->refill);
 
        unregister_netdev(vi->dev);
        cancel_delayed_work_sync(&vi->refill);

+
+       /* Free unused buffers in both send and recv, if any. */

        free_unused_bufs(vi);
 
        vdev->config->del_vqs(vi->vdev);
        free_unused_bufs(vi);
 
        vdev->config->del_vqs(vi->vdev);