Re: [PATCH net-next v7 15/16] net: ethtool: ts: Let the active time stamping layer be selectable

[Vladimir Oltean]

On Wed, Nov 22, 2023 at 08:50:00AM -0800, Jakub Kicinski wrote:
> On Wed, 22 Nov 2023 16:08:50 +0200 Vladimir Oltean wrote:
> > My understanding of Jakub's email was that he wants to see the functionality
> > offered by SIOCGHWTSTAMP and SIOCSHWTSTAMP converted to netlink. I don't
> > think that ethtool is the correct netlink family for that, given that
> > these aren't ethtool ioctls to begin with. Maybe the new netdev netlink
> > family. The conversion in its basic form would offer exactly the same
> > functionality.
> 
> Well, ethtool has been the catch all for a lot of random things
> for the longest time. The question is whether we want to extend
> ETHTOOL_GET_TS_INFO or add a third API somewhere else. And if we
> do - do we also duplicate the functionality of ETHTOOL_GET_TS_INFO
> (i.e. getting capabilities)?
> 
> My vote is that keeping it in ethtool is less bad than 3rd API.

With SIOCSHWTSTAMP also implemented by CAN (and presumably also by
wireless in the future), I do wonder whether ethtool is the right place
for the netlink conversion.

I wouldn't suggest duplicating ETHTOOL_GET_TS_INFO towards the netdev
netlink family.

> > The concept of an "active phc_index" would not explicitly exist in the
> > UAPI. Thus I'm not sure what's with this TSINFO_SET being floated around.
> > The only thing would exist is a configurable rx_filter and tx_type per
> > hwtstamp provider (aka "{phc_index, qualifier}"). User space will have
> > to learn to select the hwtstamp provider it wants to configure through
> > netlink, and use for its class of traffic.
> 
> "Active provider" is the one that has TX_ON, rx != FILTER_NONE, right?

In the "implicit" definition of an "active hwtstamp provider", yes.