net: propagate NETIF_F_HIGHDMA to vlans (c5256c51) · Commits · 戴 / test

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>

net/core/dev.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -5058,10 +5058,11 @@ int register_netdevice(struct net_device *dev)
		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);

Admin message