Re: [PATCH net v2 2/2] net: dsa: mv88e6xxx: flush the ATU when the hash algorithm changes

[Andrew Lunn]

> If changing the algorithm at runtime isn't handled fully and the hw
> AFAIU gets out of sync (i.e. static entries get lost from hw, but
> retained in the linux bridge), maybe it would make sense to reject
> changing it while e.g. a bridge exist?

Does a bridge actually make a difference?

 * @DSA_CMD_FORWARD: This tag is used on all bulk traffic passing
 *     through the switch tree, including the flows that are directed
 *     towards the CPU. Its device/port tuple encodes the original
 *     source port on which the packet ingressed. It can also be used
 *     on transmit by the CPU to defer the forwarding decision to the
 *     hardware, based on the current config of PVT/VTU/ATU
 *     etc. Source address learning takes places if enabled on the
 *     receiving DSA/CPU port.

It seems to me, a port not in a bridge will still use the ATU. And you
can add multicast entries to the ATU without being in a bridge.

If you want to make it conditional, it probably needs to be all user
ports are admin down.

      Andrew