Re: [RFC 07/31] kbuild: Remove "kmod" prefix from __KBUILD_MODNAME

[Josh Poimboeuf]

On Tue, Sep 03, 2024 at 09:58:13AM +0200, Peter Zijlstra wrote:
> On Mon, Sep 02, 2024 at 08:59:50PM -0700, Josh Poimboeuf wrote:
> > Remove the arbitrary "kmod" prefix from __KBUILD_MODNAME and add it back
> > manually in the __initcall_id() macro.
> > 
> > This makes it more consistent, now __KBUILD_MODNAME is just the
> > non-stringified version of KBUILD_MODNAME.  It will come in handy for
> > the upcoming "objtool klp diff".
> > 
> > Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> > ---
> >  include/linux/init.h | 3 ++-
> >  scripts/Makefile.lib | 2 +-
> >  2 files changed, 3 insertions(+), 2 deletions(-)
> > 
> > diff --git a/include/linux/init.h b/include/linux/init.h
> > index 58cef4c2e59a..b1921f4a7b7e 100644
> > --- a/include/linux/init.h
> > +++ b/include/linux/init.h
> > @@ -206,12 +206,13 @@ extern struct module __this_module;
> >  
> >  /* Format: <modname>__<counter>_<line>_<fn> */
> >  #define __initcall_id(fn)					\
> > +	__PASTE(kmod_,						\
> >  	__PASTE(__KBUILD_MODNAME,				\
> >  	__PASTE(__,						\
> >  	__PASTE(__COUNTER__,					\
> >  	__PASTE(_,						\
> >  	__PASTE(__LINE__,					\
> > -	__PASTE(_, fn))))))
> > +	__PASTE(_, fn)))))))
> 
> :-(

Yeah, I was just keeping the existing format here.

But actually, I strongly prefer it compared to this:

/* Format: <modname>__<counter>_<line>_<fn> */
#define __initcall_id(fn)						\
	__PASTE(kmod_,							\
		__PASTE(__KBUILD_MODNAME,				\
			__PASTE(__,					\
				__PASTE(__COUNTER__,			\
					__PASTE(_,			\
						__PASTE(__LINE__,	\
							__PASTE(_, fn)))))))

That gives headaches.  Sure, the vertically aligned version is a bit
unorthodox but it *much* easier to read if you know how to read it: just
scan down.

And the "Format:" comment at the top clarifies the result.

-- 
Josh