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Date: Thu, 18 Apr 2024 16:21:46 -0700
From: "Paul E. McKenney" <paulmck@kernel.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	elver@google.com, akpm@linux-foundation.org, tglx@linutronix.de,
	peterz@infradead.org, dianders@chromium.org, pmladek@suse.com,
	torvalds@linux-foundation.org, Arnd Bergmann <arnd@arndb.de>,
	Yujie Liu <yujie.liu@intel.com>,
	Andi Shyti <andi.shyti@linux.intel.com>
Subject: Re: [PATCH cmpxchg 13/14] xtensa: Emulate one-byte cmpxchg
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On Thu, Apr 18, 2024 at 10:06:21AM +0200, Geert Uytterhoeven wrote:
> Hi Paul,
> 
> On Mon, Apr 8, 2024 at 7:49 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> > Use the new cmpxchg_emu_u8() to emulate one-byte cmpxchg() on xtensa.
> >
> > [ paulmck: Apply kernel test robot feedback. ]
> > [ paulmck: Drop two-byte support per Arnd Bergmann feedback. ]
> >
> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> 
> Thanks for your patch!
> 
> > --- a/arch/xtensa/include/asm/cmpxchg.h
> > +++ b/arch/xtensa/include/asm/cmpxchg.h
> > @@ -74,6 +75,7 @@ static __inline__ unsigned long
> >  __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
> >  {
> >         switch (size) {
> > +       case 1:  return cmpxchg_emu_u8((volatile u8 *)ptr, old, new);
> 
> The cast is not needed.

In both cases, kernel test robot yelled at me when it was not present.

Happy to resubmit without it, though, if that is a yell that I should
have ignored.

							Thanx, Paul

> >         case 4:  return __cmpxchg_u32(ptr, old, new);
> >         default: __cmpxchg_called_with_bad_pointer();
> >                  return old;
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> -- 
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds