e1000/e1000e/igb/ixgb/ixgbe: set NETIF_F_HIGHDMA for VLAN feature flags

If the netdev->features is set with NETIF_F_HIGHDMA, we should set the
corresponding netdev->vlan_features as well to allow VLAN netdev created
on top of the real netdev to be able to also benefit from HIGHDMA on 32bit
system, reducing the performance hit that is caused by __skb_linearize(),
particularly for large send. This is fixed in this patch for all Intel e1000,
e1000e, igb, ixgbe, and ixgbe drivers since this should be beneficial
to all devices supported by these drivers.

Signed-off-by: Yi Zou <yi.zou@intel.com>
Tested-by: Emil Tantilov <emil.s.tantilov@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index 61892b80d7a..f915e9cb302 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -1858,8 +1858,10 @@ static int __devinit igb_probe(struct pci_dev *pdev,
         netdev->vlan_features |= NETIF_F_IPV6_CSUM;
         netdev->vlan_features |= NETIF_F_SG;
 
-        if (pci_using_dac)
+        if (pci_using_dac) {
                 netdev->features |= NETIF_F_HIGHDMA;
+                netdev->vlan_features |= NETIF_F_HIGHDMA;
+        }
 
         if (hw->mac.type >= e1000_82576)
                 netdev->features |= NETIF_F_SCTP_CSUM;