From: Andy Gospodarek <gospo@redhat.com>
Date: Fri, 3 Sep 2010 21:43:48 -0400
Subject: [net] vlan: control vlan device TSO status with ethtool
Message-id: <1283550228-5099-1-git-send-email-gospo@redhat.com>
Patchwork-id: 28151
O-Subject: [PATCH RHEL5.6] vlan: control vlan device TSO status with ethtool
Bugzilla: 629457
RH-Acked-by: David S. Miller <davem@redhat.com>
RH-Acked-by: Thomas Graf <tgraf@redhat.com>
RH-Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>

Patches were added in RHEL5.5 to enable TSO on vlan devices if the
proper features were set for the driver.  There was a nice performance
impact to this (I've seen 10-20% drop in CPU utilization with a simple
netperf test on my test system), but I did not want to add this to all
the network drivers unless there was a way to disable it.

A reasonable solution to control TSO status was already available
upstream, so I simply backported and tested the following upstream
commit:

	commit a204b48ed4dc31acf61090e530430ce3272b6aab
	Author: Eric Dumazet <eric.dumazet@gmail.com>
	Date:   Thu Jul 8 23:12:21 2010 -0700

	    vlan: allow TSO setting on vlan interfaces

As of right now, we will not ship with TSO on enabled on VLANs for all
hardware that supports it upstream.  Hardware supported by mlx4_en add
support in RHEL5.5 and my e1000e, ixgbe, and ixgbevf updates included
support for it.  I will post more updates to drivers as the RHEL5.6
driver updates are committed so I know my patches will actually apply.

I have tested this on e1000e, igb, igbvf, ixgbe, and ixgbevf.

This will help resolve RHBZ 629457.


diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index b6c9f6c..f6d1855 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -319,6 +319,27 @@ static int unregister_vlan_device(const char *vlan_IF_name)
 	return ret;
 }
 
+static int vlan_ethtool_set_tso(struct net_device *dev, u32 data)
+{
+	if (data) {
+		const struct vlan_dev_info *vlan = VLAN_DEV_INFO(dev);
+		struct net_device *real_dev = vlan->real_dev;
+
+		/* Underlying device must support TSO for VLAN-tagged packets
+		 * and must have TSO enabled now.
+		 */
+		if (!(real_dev->features & NETIF_F_VLAN_TSO))
+			return -EOPNOTSUPP;
+		if (!(real_dev->features & NETIF_F_TSO))
+			return -EINVAL;
+		dev->features |= NETIF_F_TSO;
+	} else {
+		dev->features &= ~NETIF_F_TSO;
+	}
+	return 0;
+}
+
+
 static u32 vlan_ethtool_get_rx_csum(struct net_device *dev)
 {
 	const struct vlan_dev_info *vlan = VLAN_DEV_INFO(dev);
@@ -330,9 +351,11 @@ static u32 vlan_ethtool_get_rx_csum(struct net_device *dev)
 	return real_dev->ethtool_ops->get_rx_csum(real_dev);
 }
 
-static const struct ethtool_ops vlan_ethtool_ops = {
+static struct ethtool_ops vlan_ethtool_ops = {
 	.get_link		= ethtool_op_get_link,
 	.get_rx_csum		= vlan_ethtool_get_rx_csum,
+	.set_tso		= vlan_ethtool_set_tso,
+	.get_tso		= ethtool_op_get_tso,
 };
 
 static void vlan_setup(struct net_device *new_dev)