Re: [PATCH v3 1/9] kernel/api: introduce kernel API specification framework

[Sasha Levin <sashal@kernel.org>]

On Sun, Apr 26, 2026 at 11:37:45PM -0400, Nathan Chancellor wrote:
> On Fri, 24 Apr 2026 12:51:21 -0400, Sasha Levin <sashal@kernel.org> wrote:
> > diff --git a/kernel/Makefile b/kernel/Makefile
> > index 6785982013dc..564315153643 100644
> > --- a/kernel/Makefile
> > +++ b/kernel/Makefile
> > @@ -59,6 +59,9 @@ obj-y += dma/
> >  obj-y += entry/
> >  obj-y += unwind/
> >  obj-$(CONFIG_MODULES) += module/
> > +obj-$(CONFIG_KAPI_SPEC) += api/
> > +# Ensure api/ is always cleaned even when CONFIG_KAPI_SPEC is not set
> > +obj- += api/
>
> If $(CONFIG_KAPI_SPEC) is not set, shouldn't
>
>   obj-$(CONFIG_KAPI_SPEC) += api/
>
> evaluate to
>
>   obj- += api/
>
> anyways? Why the duplication? This is the only place in the kernel where
> this would be needed?

You are right, the explicit "obj- += api/" is redundant. Nicolas pointed
to scripts/Makefile.clean which already evaluates obj- during
'make clean', so the conditional gate alone is sufficient. Dropped in
v4.

> > diff --git a/kernel/api/.gitignore b/kernel/api/.gitignore
> > new file mode 100644
> > index 000000000000..ca2f632621cf
> > --- /dev/null
> > +++ b/kernel/api/.gitignore
> > @@ -0,0 +1,2 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +/generated_api_specs.c
>
> This appears unused?

Correct, leftover from an earlier prototype that generated a single
combined .c file. Nothing in the current series produces
generated_api_specs.c, so the .gitignore is removed entirely in v4.

> > diff --git a/kernel/api/Kconfig b/kernel/api/Kconfig
> > new file mode 100644
> > index 000000000000..d1072728742a
> > --- /dev/null
> > +++ b/kernel/api/Kconfig
> > @@ -0,0 +1,77 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +#
> > +# Kernel API Specification Framework Configuration
> > +#
> > +
> > +config KAPI_SPEC
> > +	bool "Kernel API Specification Framework"
> > +	default n
>
> I think 'default n' is tautological since 'n' is the default for all
> bool symbols. Consider dropping it on all symbols throughtout this file.

Dropped from KAPI_SPEC, KAPI_RUNTIME_CHECKS, and KAPI_SPEC_DEBUGFS in
v4. KAPI_KUNIT_TEST already uses "default KUNIT_ALL_TESTS" and is left
unchanged.

Thanks for the review!

--
Thanks,
Sasha