Re: 4.19: udpgso_bench_tx: setsockopt zerocopy: Unknown error 524

[Willem de Bruijn]

On Tue, Jun 18, 2019 at 1:39 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Tue, Jun 18, 2019 at 01:27:14PM -0400, Willem de Bruijn wrote:
> > On Tue, Jun 18, 2019 at 1:15 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > On Tue, Jun 18, 2019 at 09:47:59AM -0700, David Miller wrote:
> > > > From: Willem de Bruijn <willemdebruijn.kernel@xxxxxxxxx>
> > > > Date: Tue, 18 Jun 2019 12:37:33 -0400
> > > >
> > > > > Specific to the above test, I can add a check command testing
> > > > > setsockopt SO_ZEROCOPY  return value. AFAIK kselftest has no explicit
> > > > > way to denote "skipped", so this would just return "pass". Sounds a
> > > > > bit fragile, passing success when a feature is absent.
> > > >
> > > > Especially since the feature might be absent because the 'config'
> > > > template forgot to include a necessary Kconfig option.
> > >
> > > That is what the "skip" response is for, don't return "pass" if the
> > > feature just isn't present.  That lets people run tests on systems
> > > without the config option enabled as you say, or on systems without the
> > > needed userspace tools present.
> >
> > I was not aware that kselftest had this feature.
> >
> > But it appears that exit code KSFT_SKIP (4) will achieve this. Okay,
> > I'll send a patch and will keep that in mind for future tests.
>
> Wonderful, thanks for doing that!

One complication: an exit code works for a single test, but here
multiple test variants are run from a single shell script.

I see that in similar such cases that use the test harness
(ksft_test_result_skip) the overall test returns success as long as
all individual cases return either success or skip.

I think it's preferable to return KSFT_SKIP if any of the cases did so
(and none returned an error). I'll do that unless anyone objects.