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Date:   Sat, 14 May 2022 00:18:20 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Uros Bizjak <ubizjak@gmail.com>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Will Deacon <will@kernel.org>,
        Boqun Feng <boqun.feng@gmail.com>,
        Mark Rutland <mark.rutland@arm.com>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Marco Elver <elver@google.com>
Subject: Re: [PATCH v2 2/2] locking/atomic/x86: Introduce arch_try_cmpxchg64
Message-ID: <20220513221820.GK76023@worktop.programming.kicks-ass.net>
References: <20220513153009.228282-1-ubizjak@gmail.com>
 <20220513153009.228282-3-ubizjak@gmail.com>
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On Fri, May 13, 2022 at 05:30:09PM +0200, Uros Bizjak wrote:


> +#define arch_try_cmpxchg64(ptr, po, n)					\
> +	((__typeof__(*(ptr)))__try_cmpxchg64((ptr), (unsigned long long *)(po), \
> +					     (unsigned long long)(n)))

That doesn't look right (unless it's so late I really can't read
anymore, in which case ignore me and I'll try again on monday). But the
return value of try_cmpxchg is bool, not typeof(*ptr).