Re: [PATCH v2 net-next 2/4] net: dsa: Link aggregation support

[Vladimir Oltean <olteanv@gmail.com>]

On Mon, Nov 30, 2020 at 03:06:08PM +0100, Tobias Waldekranz wrote:
> When a LAG joins a bridge, the DSA subsystem will treat that as each
> individual port joining the bridge. The driver may look at the port's
> LAG pointer to see if it is associated with any LAG, if that is
> required. This is analogue to how switchdev events are replicated out
> to all lower devices when reaching e.g. a LAG.

Agree with the principle. But doesn't that mean that this code:

static int dsa_slave_switchdev_blocking_event(struct notifier_block *unused,
					      unsigned long event, void *ptr)
{
	struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
	int err;

	switch (event) {
	case SWITCHDEV_PORT_OBJ_ADD:
		err = switchdev_handle_port_obj_add(dev, ptr,
						    dsa_slave_dev_check,
						    dsa_slave_port_obj_add);
		return notifier_from_errno(err);
	case SWITCHDEV_PORT_OBJ_DEL:
		err = switchdev_handle_port_obj_del(dev, ptr,
						    dsa_slave_dev_check,
						    dsa_slave_port_obj_del);
		return notifier_from_errno(err);
	case SWITCHDEV_PORT_ATTR_SET:
		err = switchdev_handle_port_attr_set(dev, ptr,
						     dsa_slave_dev_check,
						     dsa_slave_port_attr_set);
		return notifier_from_errno(err);
	}

	return NOTIFY_DONE;
}

should be replaced with something that also reacts to the case where
"dev" is a LAG? Like, for example, I imagine that a VLAN installed on a
bridge port that is a LAG should be propagated to the switch ports
beneath that LAG. Similarly for all bridge attributes.

As for FDB and MDB addresses, I think they should be propagated towards
a "logical port" corresponding to the LAG upper. I don't know how the
mv88e6xxx handles this.