Subject: Re: [PATCH v3 3/5] net: Let the active time stamping layer be selectable.

From: Jakub Kicinski <[email-masked]>
Date: Fri, 17 Mar 2023 21:03:06 -0700

On Fri, 17 Mar 2023 20:38:49 -0700 Richard Cochran wrote:
> On Fri, Mar 17, 2023 at 05:21:50PM +0200, Vladimir Oltean wrote:
> > On Thu, Mar 16, 2023 at 04:09:20PM +0100, Köry Maincent wrote:  
> > > Was there any useful work that could be continued on managing timestamp through
> > > NDOs. As it seem we will made some change to the timestamp API, maybe it is a
> > > good time to also take care of this.  
> > 
> > Not to my knowledge. Yes, I agree that it would be a good time to add an
> > NDO for hwtimestamping (while keeping the ioctl fallback), then
> > transitioning as many devices as we can, and removing the fallback when
> > the transition is complete.  
> 
> Um, user space ABI cannot be removed.

NDO meaning a dedicated callback in struct net_device_ops, so at least
for netdevs we can copy the data from user space, validate in the core
and then call the driver with a normal kernel pointer. So just an
internal refactoring, no uAPI changes.