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Date:   Fri, 12 May 2023 09:01:27 -0700
From:   "Paul E. McKenney" <paulmck@kernel.org>
To:     Mark Rutland <mark.rutland@arm.com>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org, akiyks@gmail.com,
        linux-doc@vger.kernel.org, kernel-team@meta.com,
        Will Deacon <will@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Boqun Feng <boqun.feng@gmail.com>
Subject: Re: [PATCH locking/atomic 18/19] locking/atomic: Refrain from
 generating duplicate fallback kernel-doc
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On Fri, May 12, 2023 at 02:18:48PM +0100, Mark Rutland wrote:
> On Thu, May 11, 2023 at 12:12:16PM -0700, Paul E. McKenney wrote:
> > On Thu, May 11, 2023 at 06:10:00PM +0100, Mark Rutland wrote:
> > > I think that we can restructure the ifdeffery so that each ordering variant
> > > gets its own ifdeffery, and then we could place the kerneldoc immediately above
> > > that, e.g.
> > > 
> > > 	/**
> > > 	 * arch_atomic_inc_return_release()
> > > 	 *
> > > 	 * [ full kerneldoc block here ]
> > > 	 */
> > > 	#if defined(arch_atomic_inc_return_release)
> > > 	/* defined in arch code */
> > > 	#elif defined(arch_atomic_inc_return_relaxed)
> > > 	[ define in terms of arch_atomic_inc_return_relaxed ]
> > > 	#elif defined(arch_atomic_inc_return)
> > > 	[ define in terms of arch_atomic_inc_return ]
> > > 	#else
> > > 	[ define in terms of arch_atomic_fetch_inc_release ]
> > > 	#endif
> > > 
> > > ... with similar for the mandatory ops that each arch must provide, e.g.
> > > 
> > > 	/**
> > > 	 * arch_atomic_or()
> > > 	 *
> > > 	 * [ full kerneldoc block here ]
> > > 	 */
> > > 	/* arch_atomic_or() is mandatory -- architectures must define it! */
> > > 
> > > I had a go at that restructuring today, and while local build testing indicates
> > > I haven't got it quite right, I think it's possible:
> > > 
> > >   https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=atomics/fallback-rework
> > > 
> > > Does that sound ok to you?
> > 
> > At first glance, it appears that your "TODO" locations have the same
> > information that I was using, so it should not be hard for me to adapt the
> > current kernel-doc generation to your new scheme.  (Famous last words!)
> 
> Great!
> 
> > Plus having the kernel-doc generation all in one place does have some
> > serious attractions.
> 
> :)
> 
> > I will continue maintaining my current stack, but would of course be
> > happy to port it on top of your refactoring.  If it turns out that
> > the refactoring will take a long time, we can discuss what to do in
> > the meantime.  But here is hoping that the refactoring goes smoothly!
> > That would be easier all around.  ;-)
> 
> FWIW, I think that's working now; every cross-build I've tried works.
> 
> I've updated the branch at:
> 
>   https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=atomics/fallback-rework
> 
> Tagged as:
> 
>   atomics-fallback-rework-20230512

Thank you very much!

I expect to send v2 of my original late today on the perhaps unlikely
off-chance that someone might be interested in reviewing the verbiage.

More to the point, I have started porting my changes on top of your
stack.  My thought is to have a separate "."-included script that does
the kernel-doc work.

I am also thinking in terms of putting the kernel-doc generation into
an "else" clause to the "is mandatory" check, and leaving the kernel-doc
for the mandatory functions in arch/x86/include/asm/atomic.h.

But in both cases, please let me know if something else would work better.

							Thanx, Paul