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List:       linux-kernel
Subject:    Re: [tip: locking/core] locking/pvqspinlock: Use try_cmpxchg_acquire() in trylock_clear_pending()
From:       Linus Torvalds <torvalds () linux-foundation ! org>
Date:       2024-04-11 16:31:26
Message-ID: CAHk-=wgaxi4Sau27C5yo3vty67DHz-f4L6SSOvmx1K2fQU2B_g () mail ! gmail ! com
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On Thu, 11 Apr 2024 at 06:33, tip-bot2 for Uros Bizjak
<tip-bot2@linutronix.de> wrote:
>
> Use try_cmpxchg_acquire(*ptr, &old, new) instead of
> cmpxchg_relaxed(*ptr, old, new) == old in trylock_clear_pending().

The above commit message is horribly confusing and wrong.

I was going "that's not right", because it says "use acquire instead
of relaxed" memory ordering, and then goes on to say "No functional
change intended".

But it turns out the *code* was always acquire, and it's only the
commit message that is wrong, presumably due to a bit too much
cut-and-paste.

But please fix the commit message, and use the right memory ordering
in the explanations too.

            Linus

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