Re: [PATCH v5 1/3] printf: convert self-test to KUnit

Petr Mladek
2025-03-07T16:01:03Z

On Thu 2025-03-06 09:25:43, Tamir Duberstein wrote:
> On Thu, Mar 6, 2025 at 7:25 AM Petr Mladek <pmladek@suse.com> wrote:
> >
> > On Fri 2025-02-21 15:34:30, Tamir Duberstein wrote:
> > > Convert the printf() self-test to a KUnit test.
> > >
> > > In the interest of keeping the patch reasonably-sized this doesn't
> > > refactor the tests into proper parameterized tests - it's all one big
> > > test case.
> > >
> > > --- a/lib/test_printf.c
> > > +++ b/lib/tests/printf_kunit.c
> > > @@ -57,52 +58,50 @@ do_test(int bufsize, const char *expect, int elen,
> > > va_end(aq);
> > >
> > > if (ret != elen) {
> > > - pr_warn("vsnprintf(buf, %d, \"%s\", ...) returned %d, expected %d\n",
> > > + tc_fail("vsnprintf(buf, %d, \"%s\", ...) returned %d, expected %d",
> >
> > 1. It looks a bit strange that the 1st patch replaces pr_warn() with
> > tc_fail() which hides KUNIT_FAIL().
> >
> > And the 2nd patch replaces tc_fail() with KUNIT_FAIL().
> >
> > It looks like a non-necessary churn.
> >
> > It would be better to avoid the temporary "tc_fail" and swith to
> > KUNIT_FAIL() already in this patch.
> >
> > I did not find any comment about this in the earier versions of the
> > patchset.
> >
> > Is it just a result of the evolution of the patchset or
> > is there any motivation for this?
>
> The motivation was to keep the width of the macro the same in this
> first patch for ease of review, particularly in the 7 instances where
> the invocation wraps to a second line. If you prefer I go straight to
> KUNIT_FAIL, I can make that change.

I see. It might have been useful when the patch removed the trailing '\n'.
But you are going to add it back. So there won't be any hidden change.
So I would prefer to go straight to KUNIT_FAIL().

> > > @@ -842,13 +836,15 @@ test_pointer(void)
> > > fourcc_pointer();
> > > }
> > >
> > > -static void __init selftest(void)
> > > +static void printf_test(struct kunit *test)
> > > {
> > > alloced_buffer = kmalloc(BUF_SIZE + 2*PAD_SIZE, GFP_KERNEL);
> > > if (!alloced_buffer)
> > > return;
> >
> > I would use here:
> >
> > KUNIT_ASSERT_NOT_NULL(test, alloced_buffer);
> >
> > And move the same change for the other kmalloc() location from
> > the 2nd patch.
>
> I didn't do that here because I was trying to keep this patch as small
> as possible, and I wrote that in the commit message.
>
> As for using KUNIT_ASSERT_NOT_NULL here, that would have to change
> back to an error return in the 2nd patch because this code moves into
> `suite_init`, which is called with `struct kunit_suite` rather than
> `struct kunit_test`, and KUnit assertion macros do not work with the
> former (and for good reason, because failures in suite setup cannot be
> attributed to a particular test case).

I see. KUNIT_ASSERT_NOT_NULL() can't be used in the .suite_exit() callback.

> So I'd prefer to leave this as is.

I agree to leave this as is.

Best Regards,
Petr