Re: [PATCH v2 net-next 7/9] net: netdevsim: mimic tc-taprio offload

[Vladimir Oltean]

On Tue, Aug 01, 2023 at 10:39:23AM -0700, Vinicius Costa Gomes wrote:
> Hi Vladimir,
> 
> Vladimir Oltean <vladimir.oltean@xxxxxxx> writes:
> 
> > On Wed, Jun 14, 2023 at 05:06:24PM -0700, Vinicius Costa Gomes wrote:
> >> > +static int nsim_setup_tc_taprio(struct net_device *dev,
> >> > +				struct tc_taprio_qopt_offload *offload)
> >> > +{
> >> > +	int err = 0;
> >> > +
> >> > +	switch (offload->cmd) {
> >> > +	case TAPRIO_CMD_REPLACE:
> >> > +	case TAPRIO_CMD_DESTROY:
> >> > +		break;
> >> 
> >> I was thinking about how useful would proper validation of the
> >> parameters be? Thinking that we could detect "driver API" breakages
> >> earlier, and we want it documented that the drivers should check for the
> >> things that it supports.
> >> 
> >> Makes sense?
> >
> > Sorry, I lack imagination as to what the netdevsim driver may check for.
> > The taprio offload parameters should always be valid, properly speaking,
> > otherwise the Qdisc wouldn't be passing them on to the driver. At least
> > that would be the intention. The rest are hardware specific checks for
> > hardware specific limitations. Here there is no hardware.
> >
> 
> Trying to remember what was going through my mind when I said that.
> 
> What I seem to recall is something that would help us "keep honest":
> I was worrying about someone (perhaps myself ;-) sneaking a new feature
> in taprio and forgetting to update other drivers.
> 
> I thought that adding a check for the existing parameters would help
> detect those kind of things. If anything unknown was there in the
> offload struct, netdevsim would complain loudly.
> 
> Perhaps I was worrying too much. And the way to solve that is to keep
> active attention against that during review.

Ok, so I'm not making any change to the patch set as a result of this
comment, would you agree?