Re: [RFC PATCH net-next 1/5] net: bridge: add dynamic flag to switchdev notifier

Vladimir Oltean
2023-01-19T13:41:27Z

On Thu, Jan 19, 2023 at 11:33:58AM +0200, Vladimir Oltean wrote:
> On Wed, Jan 18, 2023 at 11:14:00PM +0100, netdev@kapio-technology.com wrote:
> > > > + item->is_dyn = !test_bit(BR_FDB_STATIC, &fdb->flags);
> > >
> > > Why reverse logic? Why not just name this "is_static" and leave any
> > > further interpretations up to the consumer?
> >
> > My reasoning for this is that the common case is to have static entries,
> > thus is_dyn=false, so whenever someone uses a switchdev_notifier_fdb_info
> > struct the common case does not need to be entered.
> > Otherwise it might also break something when someone uses this struct and if
> > it was 'is_static' and they forget to code is_static=true they will get
> > dynamic entries without wanting it and it can be hard to find such an error.
>
> I'll leave it up to bridge maintainers if this is preferable to patching
> all callers of SWITCHDEV_FDB_ADD_TO_BRIDGE such that they set is_static=true.

Actually, why would you assume that all users of SWITCHDEV_FDB_ADD_TO_BRIDGE
want to add static FDB entries? You can't avoid inspecting the code and
making sure that the is_dyn/is_static flag is set correctly either way.