Re: [PATCH net] net: dsa: mv88e6xxx: override existent unicast portvec in port_fdb_add

On Sun, Jan 31, 2021 at 8:39 AM Vladimir Oltean [off-list ref] wrote:

Tobias has a point in a way too, you should get used to adding the
'master static' flags to your bridge fdb commands, otherwise weird
things like this could happen. The faulty code can only be triggered
when going through dsa_legacy_fdb_add, but it is still faulty
nonetheless.

This bug is exposed when I try your patch series on kernel 5.4
https://lore.kernel.org/netdev/20210106095136.224739-1-olteanv@gmail.com/ (local)
https://lore.kernel.org/netdev/20210116012515.3152-1-tobias@waldekranz.com/ (local)

Without this patch, DSA will add a new port bit to the existing
portvec when a client moves to the software part of a bridge. When it
moves away, DSA will clear the port bit but the existing one will
remain static. This results in connection issues when the client moves
to a different port of the switch, and the kernel log below.

mv88e6085 f1072004.mdio-mii:00: ATU member violation for
xx:xx:xx:xx:xx:xx portvec dc00 spid 0