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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Thu, 26 May 2022 09:56:19 -0700
Message-ID: <CAHk-=wg1xKLV3aWWvp46295yFkAnzxv3pmehoHk6RuEwB0pa_Q@mail.gmail.com>
Subject: Re: [PATCH 1/2] locking/lockref: Use try_cmpxchg64 in CMPXCHG_LOOP macro
To:     Uros Bizjak <ubizjak@gmail.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Russell King <linux@armlinux.org.uk>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Heiko Carstens <hca@linux.ibm.com>
Cc:     "the arch/x86 maintainers" <x86@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>, Waiman.Long@hp.com,
        Paul McKenney <paulmck@linux.vnet.ibm.com>
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On Wed, May 25, 2022 at 9:47 AM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Ack on this one regardless of the 32-bit x86 question.

.. and with confirmation from Michael and Mark (and the analysis from
Uros on the fallback code), I've applied this to my tree.

NOTE!

I have *not* applied the second patch with the x86-32 change to enable
this on 32-bit with CMPXCHG8B enabled. I think that's independent, and
will leave it up to the x86 maintainers.  Plus I think the patch
should be simplified.

             Linus