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From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Thu, 18 Apr 2024 10:06:21 +0200
Message-ID: <CAMuHMdXAB-9GPqNBJKF=JtWNfhBv168N6eko-9VcLmLSeQaS4Q@mail.gmail.com>
Subject: Re: [PATCH cmpxchg 13/14] xtensa: Emulate one-byte cmpxchg
To: "Paul E. McKenney" <paulmck@kernel.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>
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Hi Paul,

On Mon, Apr 8, 2024 at 7:49=E2=80=AFPM 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.

>         case 4:  return __cmpxchg_u32(ptr, old, new);
>         default: __cmpxchg_called_with_bad_pointer();
>                  return old;

Gr{oetje,eeting}s,

                        Geert

--=20
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k=
org

In personal conversations with technical people, I call myself a hacker. Bu=
t
when I'm talking to journalists I just say "programmer" or something like t=
hat.
                                -- Linus Torvalds