Re: [PATCH v2 net-next 04/11] net: bridge: offload initial and final port flags through switchdev

[Vladimir Oltean]

On Wed, Feb 10, 2021 at 12:59:49PM +0200, Ido Schimmel wrote:
> > > The reverse, during unlinking, would be to refuse unlinking if the upper
> > > has uppers of its own. netdev_upper_dev_unlink() needs to learn to
> > > return an error and callers such as team/bond need to learn to handle
> > > it, but it seems patchable.
> >
> > Again, this was treated prior to my deletion in this series and not by
> > erroring out, I just really didn't think it through.
> >
> > So you're saying that if we impose that all switchdev drivers restrict
> > the house of cards to be constructed from the bottom up, and destructed
> > from the top down, then the notification of bridge port flags can stay
> > in the bridge layer?
>
> I actually don't think it's a good idea to have this in the bridge in
> any case. I understand that it makes sense for some devices where
> learning, flooding, etc are port attributes, but in other devices these
> can be {port,vlan} attributes and then you need to take care of them
> when a vlan is added / deleted and not only when a port is removed from
> the bridge. So for such devices this really won't save anything. I would
> thus leave it to the lower levels to decide.

Just for my understanding, how are per-{port,vlan} attributes such as
learning and flooding managed by the Linux bridge? How can I disable
flooding only in a certain VLAN?