From: Andrei Vagin <ava...@openvz.org> Date: Wed, 15 Mar 2017 17:41:14 -0700
> wanted_features is a set of features which have to be enabled if a > hardware allows that. > > Currently when a vlan device is created, its wanted_features is set to > current features of its base device. > > The problem is that the base device can get new features and they are > not propagated to vlan-s of this device. > > If we look at bonding devices, they doesn't have this problem and this > patch suggests to fix this issue by the same way how it works for bonding > devices. > > We meet this problem, when we try to create a vlan device over a bonding > device. When a system are booting, real devices require time to be > initialized, so bonding devices created without slaves, then vlan > devices are created and only then ethernet devices are added to the > bonding device. As a result we have vlan devices with disabled > scatter-gather. > > * create a bonding device > $ ip link add bond0 type bond > $ ethtool -k bond0 | grep scatter > scatter-gather: off > tx-scatter-gather: off [requested on] > tx-scatter-gather-fraglist: off [requested on] > > * create a vlan device > $ ip link add link bond0 name bond0.10 type vlan id 10 > $ ethtool -k bond0.10 | grep scatter > scatter-gather: off > tx-scatter-gather: off > tx-scatter-gather-fraglist: off > > * Add a slave device to bond0 > $ ip link set dev eth0 master bond0 > > And now we can see that the bond0 device has got the scatter-gather > feature, but the bond0.10 hasn't got it. > [root@laptop linux-task-diag]# ethtool -k bond0 | grep scatter > scatter-gather: on > tx-scatter-gather: on > tx-scatter-gather-fraglist: on > [root@laptop linux-task-diag]# ethtool -k bond0.10 | grep scatter > scatter-gather: off > tx-scatter-gather: off > tx-scatter-gather-fraglist: off > > With this patch the vlan device will get all new features from the > bonding device. > > Here is a call trace how features which are set in this patch reach > dev->wanted_features. > > register_netdevice > vlan_dev_init > ... > dev->hw_features = NETIF_F_HW_CSUM | NETIF_F_SG | > NETIF_F_FRAGLIST | NETIF_F_GSO_SOFTWARE | > NETIF_F_HIGHDMA | NETIF_F_SCTP_CRC | > NETIF_F_ALL_FCOE; > > dev->features |= dev->hw_features; > ... > dev->wanted_features = dev->features & dev->hw_features; > __netdev_update_features(dev); > vlan_dev_fix_features > ... > > Signed-off-by: Andrei Vagin <ava...@openvz.org> Applied, thanks.
