vmxnet3: Fix inconsistent LRO state after initialization
Thomas Jarosch [Mon, 16 May 2011 06:28:15 +0000 (06:28 +0000)]
During initialization of vmxnet3, the state of LRO
gets out of sync with netdev->features.

This leads to very poor TCP performance in a IP forwarding
setup and is hitting many VMware users.

Simplified call sequence:
1. vmxnet3_declare_features() initializes "adapter->lro" to true.

2. The kernel automatically disables LRO if IP forwarding is enabled,
so vmxnet3_set_flags() gets called. This also updates netdev->features.

3. Now vmxnet3_setup_driver_shared() is called. "adapter->lro" is still
set to true and LRO gets enabled again, even though
netdev->features shows it's disabled.

Fix it by updating "adapter->lro", too.

The private vmxnet3 adapter flags are scheduled for removal
in net-next, see commit a0d2730c9571aeba793cb5d3009094ee1d8fda35
"net: vmxnet3: convert to hw_features".

Patch applies to 2.6.37 / 2.6.38 and 2.6.39-rc6.

Please CC: comments.

Signed-off-by: Thomas Jarosch <thomas.jarosch@intra2net.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vmxnet3/vmxnet3_ethtool.c

index 51f2ef1..9764672 100644 (file)
@@ -311,6 +311,9 @@ vmxnet3_set_flags(struct net_device *netdev, u32 data)
                /* toggle the LRO feature*/
                netdev->features ^= NETIF_F_LRO;
 
+               /* Update private LRO flag */
+               adapter->lro = lro_requested;
+
                /* update harware LRO capability accordingly */
                if (lro_requested)
                        adapter->shared->devRead.misc.uptFeatures |=