On Mon, Jun 25, 2018 at 02:45:24PM -0600, David Ahern wrote:
> On 6/25/18 4:30 AM, Chas Williams wrote:
> > vlan_changelink silently ignores attempts to change the vlan id
> > or protocol id of an existing vlan interface. Implement by adding
> > the new vlan id and protocol to the interface's vlan group and then
> > removing the old vlan id and protocol from the vlan group.
> >
> > Signed-off-by: Chas Williams <3ch...@gmail.com>
> > ---
> > include/linux/netdevice.h | 1 +
> > net/8021q/vlan.c | 4 ++--
> > net/8021q/vlan.h | 2 ++
> > net/8021q/vlan_netlink.c | 38 ++++++++++++++++++++++++++++++++++++++
> > net/core/dev.c | 1 +
> > 5 files changed, 44 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> > index 3ec9850c7936..a95ae238addf 100644
> > --- a/include/linux/netdevice.h
> > +++ b/include/linux/netdevice.h
> > @@ -2409,6 +2409,7 @@ enum netdev_cmd {
> > NETDEV_CVLAN_FILTER_DROP_INFO,
> > NETDEV_SVLAN_FILTER_PUSH_INFO,
> > NETDEV_SVLAN_FILTER_DROP_INFO,
> > + NETDEV_CHANGEVLAN,
> > };
> > const char *netdev_cmd_to_name(enum netdev_cmd cmd);
> >
>
> you add the new notifier, but do not add any hooks to catch and process it.
>
> Personally, I think it is a bit sketchy to change the vlan id on an
> existing device and I suspect it will cause latent errors.
+1
>
> What's your use case for trying to implement the change versus causing
> it to generate an unsupported error?
>
> If this patch does get accepted, I believe the mlxsw switchdev driver
> will be impacted.
Yes, at minimum we need to return an error for NETDEV_CHANGEVLAN, but
looking at the code it seems that there's no proper rollback.
Thanks for the Cc, David.
