In D30463#685511, @markj wrote:

I don't understand this change. If you look at EVENTHANDLER_INVOKE, it traverses the list of registered handlers and calls each one with

_t->eh_func(_ep->ee_arg , ## __VA_ARGS__);

so the argument passed with EVENTHANDLER_REGISTER is the first parameter, followed by the parent ifnet and VID. iflib specifies the ctx (stored in ifp->if_softc) as the argument, and in iflib_vlan_register() we compare the argument with ifp->if_softc.

I tried adding some prints around this code and configured a vlan on an igb interface, and iflib indeed handled the event. So I can't see what problem this diff is fixing.

In D30463#685828, @erj wrote:

I also don't really understand what this is supposed to fix; we haven't had problems registering VLANs at all.