On Thu, Nov 19, 2020 at 12:52:14PM +0100, Tobias Waldekranz wrote: > > it appears that I don't need the .port_lag_change callback, and that the > > Ok, does ocelot automatically rebalance the LAG based on link state? I > took a quick look through the datasheet for another switch from > Vitesse, and it explicitly states that you need to update a table on > link changes. > > I.e. in this situation: > > br0 > / | > lag | > /|\ | > 1 2 3 4 > | | | \ > | | | B > | | | > 1 2 3 > A > > If you unplug cable 1, does the hardware rebalance all flows between > A<->B to only use 2 and 3 without software assistance? If not, you > will loose 1/3 of your flows.
Yes, you're right, the switch doesn't rebalance the aggregation codes across the remaining ports automatically. In my mind I was subconsiously hoping that would be the case, because I need to make use of the information in struct dsa_lag in non-DSA code (long story, but the drivers/net/dsa/ocelot code shares the implementation with drivers/net/ethernet/mscc/ocelot* which is a switchdev-only driver). It doesn't mean that keeping state in dp->lag is the wrong thing to do, it's just that this is an extra challenge for an already odd driver, that I will have to see how I deal with :D
