Re: [PATCH net-next] selftests: drv-net: hide the devlink port_split test

[Jakub Kicinski <kuba@kernel.org>]

On Mon, 10 Aug 2026 13:04:48 +0200 Petr Machata wrote:
> > The devlink port_split test has limited applicability.
> > NICs (as opposed to switches) require at least a re-probe
> > to apply the split configuration.  
> 
> Interesting, apparently some NICs require reboot after devlink port
> split. Hmm, should I just move the test to drivers/mlxsw?

It's not really mlxsw specific in any way :S
The cmode + NETIF compatibility would be my long term preference.

> > On top of that the test is not compatible with our driver env,
> > it just splits all ports on the system, not only what NETIF
> > points at.
> >
> > Long term we may want to add some indication in devlink whether
> > the port splitting is runtime (cmode of sorts), and fix the
> > test to follow driver env. But since no (known) NIC driver can
> > support runtime anyway let's just hide the test from the selftest
> > framework by moving it to extra files.  
> 
> Sure, go for it.
> 
> > Having this test randomly break unrelated NICs within the DUT
> > makes people implement allow-lists for ksft, which then means
> > their setups don't run new tests.  
> 
> So I'm fine with the patch, but I don't buy this argument. People
> presumably understand that allow-listing implies that only the, well,
> allowed tests will be run.

One note here - that's a fine position to take for downstream CIs.
But upstream / in NIPA we want to test the drivers as much as we want
to test the tests. It's _very_ useful during review to see how well 
the test works across the runners before merging. So allowlists are
explicitly a no-no for NIPA reporting.

> Presumably there was a history of new stuff
> blowing up, or gradual enablement or whatever, otherwise why not just
> blacklist the one problematic one? I.e. don't blame the existence of
> allow-lists on devlink_port_split.

IIRC Intel devs mentioned port split as problematic explicitly.
I also had issues with it in NIPA.

But fair point, maybe once the auto-neg / link config tests appear
upstream this will be more prevalent problem. For now devlink port
split is the only one.. let's just squirrel it away.

> Reviewed-by: Petr Machata <petrm@nvidia.com>

Thanks! I may need to respin and use PROGS_EXTENDED as AI suggests.