Re: [PATCH net] add support of IFF_XMIT_DST_RELEASE bit in vlan

[Eric Dumazet]

On Fri, 2017-11-03 at 01:39 +0300, Vadim Fedorenko wrote:

> Do you mean what happens with vlan device with real_dev is bonding ?
> 
> With patches:
> 1) A is added
>    bond_enslave()
>      bond_compute_features()
>              -> bond_dev IFF_XMIT_DST_RELEASE is not changed (set)
>        netdev_change_features()
>          vlan_device_event(event=NETDEV_FEAT_CHANGE)
>            vlan_transfer_features()
>              -> vlan_dev IFF_XMIT_DST_RELEASE is not changed (still set)
> Then B is added
>    bond_enslave()
>      bond_compute_features()
>              -> bond_dev IFF_XMIT_DST_RELEASE is changed (cleared)
>        netdev_change_features()
>          vlan_device_event(event=NETDEV_FEAT_CHANGE)
>            vlan_transfer_features()
>              -> vlan_dev IFF_XMIT_DST_RELEASE is changed (cleared)
> 
> 2) B is added
>    bond_enslave()
>      bond_compute_features()
>              -> bond_dev IFF_XMIT_DST_RELEASE is changed (cleared)
>        netdev_change_features()
>          vlan_device_event(event=NETDEV_FEAT_CHANGE)
>            vlan_transfer_features()
>              -> vlan_dev IFF_XMIT_DST_RELEASE is changed (cleared)
> Then A is added
>    bond_enslave()
>      bond_compute_features()
>              -> bond_dev IFF_XMIT_DST_RELEASE is not changed (cleared)
>        netdev_change_features()
>          vlan_device_event(event=NETDEV_FEAT_CHANGE)
>            vlan_transfer_features()
>              -> vlan_dev IFF_XMIT_DST_RELEASE is not changed (cleared).
> 
> Without patches:
> 1) A is added
>    bond_enslave()
>      bond_compute_features()
>              -> bond_dev IFF_XMIT_DST_RELEASE is not changed (set)
>        netdev_change_features()
>          vlan_device_event(event=NETDEV_FEAT_CHANGE)
>            vlan_transfer_features()
>               -> vlan_dev IFF_XMIT_DST_RELEASE is not changed (cleared)
> 
> Then B is added
>    bond_enslave()
>      bond_compute_features()
>               -> bond_dev IFF_XMIT_DST_RELEASE is changed (cleared)
>        netdev_change_features()
>          vlan_device_event(event=NETDEV_FEAT_CHANGE)
>            vlan_transfer_features()
>               -> vlan_dev IFF_XMIT_DST_RELEASE is not changed(cleared)
> 2) B is added
>    bond_enslave()
>      bond_compute_features()
>               -> bond_dev IFF_XMIT_DST_RELEASE is changed (cleared)
>        netdev_change_features()
>          vlan_device_event(event=NETDEV_FEAT_CHANGE)
>            vlan_transfer_features()
>               -> vlan_dev IFF_XMIT_DST_RELEASE is not changed(cleared)
> Then A is added
>    bond_enslave()
>      bond_compute_features()
>               -> bond_dev IFF_XMIT_DST_RELEASE is not changed (cleared)
>        netdev_change_features()
>          vlan_device_event(event=NETDEV_FEAT_CHANGE)
>            vlan_transfer_features()
>               -> vlan_dev IFF_XMIT_DST_RELEASE is not changed (cleared).
> 

Thanks for this investigation !

Reviewed-by: Eric Dumazet <eduma...@google.com>