On Friday 30 January 2009 09:35:12 Alex Williamson wrote: 

+static void virtnet_set_rx_mode(struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	u8 promisc, allmulti;
+
+	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
+		return;

Hmm, this check duplicates the one in virtnet_send_command; after
all your patches, is it ever called with !VIRTIO_NET_F_CTRL_RX?  Maybe it should be a BUG_ON in there?

+	promisc = ((dev->flags & IFF_PROMISC) != 0 || dev->uc_count > 0);
+	allmulti = ((dev->flags & IFF_ALLMULTI) != 0 || dev->mc_count > 0);
+
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
+				  VIRTIO_NET_CTRL_RX_PROMISC,
+				  &promisc, sizeof(promisc)))
+		printk(KERN_WARNING "%s: Failed to %sable promisc mode.\n",
+		       dev->name, promisc ? "en" : "dis");
+
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
+				  VIRTIO_NET_CTRL_RX_ALLMULTI,
+				  &allmulti, sizeof(allmulti)))
+		printk(KERN_WARNING "%s: Failed to %sable allmulti mode.\n",
+		       dev->name, allmulti ? "en" : "dis");
+}

Hmm, we can't do anything with this error.  I'd be very tempted to define the API to say "this can't fail".  Leave this code in as a sanity check, but have a comment to that effect?

+#define VIRTIO_NET_CTRL_RX    0
+ #define VIRTIO_NET_CTRL_RX_PROMISC      0
+ #define VIRTIO_NET_CTRL_RX_ALLMULTI     1

Comment above/beside these two perhaps?
/* Supported if VIRTIO_NET_F_CTRL_RX */

Cheers,
Rusty.