Subject: Re: [PATCH net-next 4/4] net: dsa: set configure_vlan_while_not_filtering to true by default

From: Kurt Kanzenbach <[email-masked]>
Date: Tue, 08 Sep 2020 12:14:12 +0200

On Mon Sep 07 2020, Vladimir Oltean wrote:
> From: Vladimir Oltean <[email-masked]>
>
> As explained in commit 54a0ed0df496 ("net: dsa: provide an option for
> drivers to always receive bridge VLANs"), DSA has historically been
> skipping VLAN switchdev operations when the bridge wasn't in
> vlan_filtering mode, but the reason why it was doing that has never been
> clear. So the configure_vlan_while_not_filtering option is there merely
> to preserve functionality for existing drivers. It isn't some behavior
> that drivers should opt into. Ideally, when all drivers leave this flag
> set, we can delete the dsa_port_skip_vlan_configuration() function.
>
> New drivers always seem to omit setting this flag, for some reason.

Yes, because it's not well documented, or is it? Before writing the
hellcreek DSA driver, I've read dsa.rst documentation to find out what
callback function should to what. Did I miss something?

> So let's reverse the logic: the DSA core sets it by default to true
> before the .setup() callback, and legacy drivers can turn it off. This
> way, new drivers get the new behavior by default, unless they
> explicitly set the flag to false, which is more obvious during review.

Yeah, that behavior makes more sense to me. Thank you.

Thanks,
Kurt