From: Mark McLoughlin <markmc@redhat.com>
Date: Tue, 21 Oct 2008 10:44:05 +0100
Subject: [xen] virtio_net: some relatively minor fixes
Message-id: 1224582245.708.24.camel@blaa
O-Subject: [RHEL5.3 PATCH 0/4] virtio_net: some relatively minor fixes
Bugzilla: 468034
RH-Acked-by: Rik van Riel <riel@redhat.com>
RH-Acked-by: Don Dutile <ddutile@redhat.com>
RH-Acked-by: Bill Burns <bburns@redhat.com>
RH-Acked-by: Herbert Xu <herbert.xu@redhat.com>
RH-Acked-by: Chris Wright <chrisw@redhat.com>

https://bugzilla.redhat.com/446214

What follows are four relatively minor fixes to the backported
virtio_net drivers which were added in 2.6.18-110.el5. They can
either be committed as a single patch or four individual patches.

The patches are:

 1) Fix leaked netdev->refcnt - it can often be impossible to unload
    the virtio_net driver with rmmod because of a device refcount
    leak. The bug does not exist upstream because it is in code added
    as part of the backport.

 2) Support ethtool offload queries - a simple and safe ethtool change
    needed because of differences between 2.6.18 and upstream.

 3) Make use of napi_weight module param - the backport caused the
    napi_weight module param to be ignored.

 4) Recycle some more rx buffer pages - trivial, safe optimization
    which will be in 2.6.28.

We have tested all these patches quite extensively as part of our
general testing efforts around RHEL5 virtio drivers.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d743b1e..8e8da1d 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -84,6 +84,16 @@ static void give_a_page(struct virtnet_info *vi, struct page *page)
 	vi->pages = page;
 }
 
+static void trim_pages(struct virtnet_info *vi, struct sk_buff *skb)
+{
+	unsigned int i;
+
+	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+		give_a_page(vi, skb_shinfo(skb)->frags[i].page);
+	skb_shinfo(skb)->nr_frags = 0;
+	skb->data_len = 0;
+}
+
 static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
 {
 	struct page *p = vi->pages;
@@ -124,14 +134,8 @@ static void receive_skb(struct net_device *dev, struct sk_buff *skb,
 	}
 	len -= sizeof(struct virtio_net_hdr);
 
-	if (len <= MAX_PACKET_LEN) {
-		unsigned int i;
-
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
-			give_a_page(dev->priv, skb_shinfo(skb)->frags[i].page);
-		skb->data_len = 0;
-		skb_shinfo(skb)->nr_frags = 0;
-	}
+	if (len <= MAX_PACKET_LEN)
+		trim_pages(dev->priv, skb);
 
 	err = pskb_trim(skb, len);
 	if (err) {
@@ -231,6 +235,7 @@ static void try_fill_recv(struct virtnet_info *vi)
 		err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
 		if (err) {
 			skb_unlink(skb, &vi->recv);
+			trim_pages(vi, skb);
 			kfree_skb(skb);
 			break;
 		}
@@ -286,6 +291,7 @@ again:
 	if (!no_work && netif_rx_schedule_prep(vi->dev)) {
 		vi->rvq->vq_ops->disable_cb(vi->rvq);
 		__netif_rx_schedule(vi->dev);
+		dev_put(vi->dev);
 		goto again;
 	}
 
@@ -492,7 +498,11 @@ static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
 
 static struct ethtool_ops virtnet_ethtool_ops = {
 	.set_tx_csum = virtnet_set_tx_csum,
+	.get_tx_csum = ethtool_op_get_tx_csum,
 	.set_sg = ethtool_op_set_sg,
+	.get_sg = ethtool_op_get_sg,
+	.set_tso = ethtool_op_set_tso,
+	.get_tso = ethtool_op_get_tso,
 };
 
 static int virtnet_probe(struct virtio_device *vdev)
@@ -548,7 +558,7 @@ static int virtnet_probe(struct virtio_device *vdev)
 	/* Set up our device-specific information */
 	vi = netdev_priv(dev);
 	dev->poll = virtnet_poll;
-	dev->weight = 16;
+	dev->weight = napi_weight;
 	vi->dev = dev;
 	vi->vdev = vdev;
 	vdev->priv = vi;