Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 12 Apr 2023 11:55:31 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     linux-kernel@vger.kernel.org,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: Re: [PATCH v1 1/1] kernel.h: Split out COUNT_ARGS() and
 CONCATENATE()
Message-Id: <20230412115531.17bb1aed232952c79aba0f2a@linux-foundation.org>
In-Reply-To: <ZDaqi1jE0Fkg5BSp@smile.fi.intel.com>
References: <20230411102454.85898-1-andriy.shevchenko@linux.intel.com>
        <20230411152119.c9bb83a8566e37f6d8dbc590@linux-foundation.org>
        <ZDaqi1jE0Fkg5BSp@smile.fi.intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Wed, 12 Apr 2023 15:56:43 +0300 Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> On Tue, Apr 11, 2023 at 03:21:19PM -0700, Andrew Morton wrote:
> > On Tue, 11 Apr 2023 13:24:54 +0300 Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> > 
> > > kernel.h is being used as a dump for all kinds of stuff for a long time.
> > > The COUNT_ARGS() and CONCATENATE() macros may be used in some places
> > > without need of the full kernel.h dependency train with it.
> > > 
> > > Here is the attempt on cleaning it up by splitting out these macros().
> > > 
> > > --- a/include/linux/kernel.h
> > > +++ b/include/linux/kernel.h
> > > @@ -13,6 +13,7 @@
> > >  
> > >  #include <linux/stdarg.h>
> > >  #include <linux/align.h>
> > > +#include <linux/args.h>
> > 
> > A more energetic patch would have included args.h into each file which
> > calls COUNT_ARGS() and CONCATENATE(), and not included args.h into
> > kernel.h.  And that appears to be very easy - only bpf uses these things?
> > 
> > In fact these macros are so weird and ugly I'd be inclined to move them
> > into some bpf header so we don't have to see them again.  No
> > args.h, which might avoid encouraging others to use them.
> 
> We have more users than one 

I cant find any?

> and a couple of users that reimplement this macro
> under different names.

Where are these?

What the heck does it do and why is it so ugly and why isn't it
documented.  Shudder.

I suppose if there are other callers(?) then we could hide it in a
countargs.h and not include that into kernel.h.