On Tue, Feb 09, 2021 at 10:20:45PM +0200, Vladimir Oltean wrote: > On Tue, Feb 09, 2021 at 08:51:00PM +0200, Ido Schimmel wrote: > > On Tue, Feb 09, 2021 at 05:19:29PM +0200, Vladimir Oltean wrote: > > > So switchdev drivers operating in standalone mode should disable address > > > learning. As a matter of practicality, we can reduce code duplication in > > > drivers by having the bridge notify through switchdev of the initial and > > > final brport flags. Then, drivers can simply start up hardcoded for no > > > address learning (similar to how they already start up hardcoded for no > > > forwarding), then they only need to listen for > > > SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS and their job is basically done, no > > > need for special cases when the port joins or leaves the bridge etc. > > > > How are you handling the case where a port leaves a LAG that is linked > > to a bridge? In this case the port becomes a standalone port, but will > > not get this notification. > > Apparently the answer to that question is "I delete the code that makes > this use case work", how smart of me. Thanks. Not sure how you expect to interpret this. > > Unless you have any idea how I could move the logic into the bridge, I > guess I'm stuck with DSA and all the other switchdev drivers having this > forest of corner cases to deal with. At least I can add a comment so I'm > not tempted to delete it next time. There are too many moving pieces with stacked devices. It is not only LAG/bridge. In L3 you have VRFs, SVIs, macvlans etc. It might be better to gracefully / explicitly not handle a case rather than pretending to handle it correctly with complex / buggy code. For example, you should refuse to be enslaved to a LAG that already has upper devices such as a bridge. You are probably not handling this correctly / at all. This is easy. Just a call to netdev_has_any_upper_dev(). The reverse, during unlinking, would be to refuse unlinking if the upper has uppers of its own. netdev_upper_dev_unlink() needs to learn to return an error and callers such as team/bond need to learn to handle it, but it seems patchable.
