Vladimir Oltean ec638740fc net: switchdev: remove lag_mod_cb from switchdev_handle_fdb_event_to_device ... When the switchdev_handle_fdb_event_to_device() event replication helper was created, my original thought was that FDB events on LAG interfaces should most likely be special-cased, not just replicated towards all switchdev ports beneath that LAG. So this replication helper currently does not recurse through switchdev lower interfaces of LAG bridge ports, but rather calls the lag_mod_cb() if that was provided. No switchdev driver uses this helper for FDB events on LAG interfaces yet, so that was an assumption which was yet to be tested. It is certainly usable for that purpose, as my RFC series shows: https://patchwork.kernel.org/project/netdevbpf/cover/20220210125201.2859463-1-vladimir.oltean@nxp.com/ however this approach is slightly convoluted because: - the switchdev driver gets a "dev" that isn't its own net device, but rather the LAG net device. It must call switchdev_lower_dev_find(dev) in order to get a handle of any of its own net devices (the ones that pass check_cb). - in order for FDB entries on LAG ports to be correctly refcounted per the number of switchdev ports beneath that LAG, we haven't escaped the need to iterate through the LAG's lower interfaces. Except that is now the responsibility of the switchdev driver, because the replication helper just stopped half-way. So, even though yes, FDB events on LAG bridge ports must be special-cased, in the end it's simpler to let switchdev_handle_fdb_* just iterate through the LAG port's switchdev lowers, and let the switchdev driver figure out that those physical ports are under a LAG. The switchdev_handle_fdb_event_to_device() helper takes a "foreign_dev_check" callback so it can figure out whether @dev can autonomously forward to @foreign_dev. DSA fills this method properly: if the LAG is offloaded by another port in the same tree as @dev, then it isn't foreign. If it is a software LAG, it is foreign - forwarding happens in software. Whether an interface is foreign or not decides whether the replication helper will go through the LAG's switchdev lowers or not. Since the lan966x doesn't properly fill this out, FDB events on software LAG uppers will get called. By changing lan966x_foreign_dev_check(), we can suppress them. Whereas DSA will now start receiving FDB events for its offloaded LAG uppers, so we need to return -EOPNOTSUPP, since we currently don't do the right thing for them. Cc: Horatiu Vultur <horatiu.vultur@microchip.com> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>		2022-02-24 21:31:43 -08:00
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Kconfig
Makefile	net: switchdev: use obj-$(CONFIG_NET_SWITCHDEV) form in net/Makefile	2021-01-27 17:03:52 -08:00
switchdev.c	net: switchdev: remove lag_mod_cb from switchdev_handle_fdb_event_to_device	2022-02-24 21:31:43 -08:00