net: propagate NETIF_F_HIGHDMA to vlans
Automatically allows vlans to get NETIF_F_HIGHDMA if underlying device
supports it.
On 32bit arches (and more precisely if CONFIG_HIGHMEM is enabled), it
can help to reduce cost of illegal_highdma() and __skb_linearize()
calls.
Tested on tg3 , bnx2, bonding, this worked very well.
This is a generalization of a patch provided by Yi Zou & Jeff Kirsher.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 2c7934f..e0c0b86 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5058,10 +5058,11 @@
if (dev->features & NETIF_F_SG)
dev->features |= NETIF_F_GSO;
- /* Enable GRO for vlans by default if dev->features has GRO also.
- * vlan_dev_init() will do the dev->features check.
+ /* Enable GRO and NETIF_F_HIGHDMA for vlans by default,
+ * vlan_dev_init() will do the dev->features check, so these features
+ * are enabled only if supported by underlying device.
*/
- dev->vlan_features |= NETIF_F_GRO;
+ dev->vlan_features |= (NETIF_F_GRO | NETIF_F_HIGHDMA);
ret = call_netdevice_notifiers(NETDEV_POST_INIT, dev);
ret = notifier_to_errno(ret);