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

[Vladimir Oltean]

On Thu, Nov 23, 2023 at 09:32:05AM -0800, Jakub Kicinski wrote:
> On Thu, Nov 23, 2023 at 04:00:56PM +0100, Köry Maincent wrote:
> > So, do we have a consensus? Vlad, do you agree on putting all under ethtool?
> > 
> > ETHTOOL_GET_TS_INFO will be in charge of replacing the SIOCGHWSTAMP
> > implementation. Need to add ETHTOOL_A_TSINFO_PHC_INDEX
> > ETHTOOL_A_TSINFO_QUALIFIER to the request.
> > 
> > ETHTOOL_GET_TS_INFO will list all the hwtstamp provider (aka "{phc_index,
> > qualifier}") through the dumpit callback. I will add a filter to be able to
> > list only the hwtstamp provider of one netdev.
> > 
> > ETHTOOL_SET_TS_INFO will be in charge of replacing the SIOCSHWSTAMP
> > implementation.
> 
> If not we can do a vote/poll? Maybe others don't find the configuration
> of timestamping as confusing as me.

If you mean the ETHTOOL_MSG_TSINFO_GET netlink message (ETHTOOL_GET_TS_INFO
is an ioctl), you're saying that you want to move the entire contents of
SIOCGHWSTAMP there, by making the kernel call ndo_hwtstamp_get() in
addition to the existing __ethtool_get_ts_info()?

Yeah, I don't know, I don't have a real objection, I guess it's fine.

What will be a bit of an "?!" moment for users is when ethtool gains
support for the SIOCGHWSTAMP/SIOCSHWSTAMP netlink replacements, but not
for the original ioctls. So hwstamp_ctl will be able to change timestamping
configuration, but ethtool wouldn't - all on the same system. Unless
ethtool gains an ioctl fallback for a ioctl that was never down its alley.

But by all means, still hold a poll if you want to. I would vote for
ethtool netlink, not because it's great, just because I don't have a
better alternative to propose.