From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Uros Bizjak <ubizjak@gmail.com>
Cc: linux-kernel@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>
Subject: Re: [PATCH] random: Use try_cmpxchg in _credit_init_bits
Date: Sat, 16 Jul 2022 20:29:12 +0200 [thread overview]
Message-ID: <YtMDeHO93SQh0ufA@zx2c4.com> (raw)
In-Reply-To: <20220714182822.25142-1-ubizjak@gmail.com>
Hi Uros,
On Thu, Jul 14, 2022 at 08:28:22PM +0200, Uros Bizjak wrote:
> Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
> _credit_init_bits. x86 CMPXCHG instruction returns success in ZF flag,
> so this change saves a compare after cmpxchg (and related move
> instruction in front of cmpxchg).
>
> Also, try_cmpxchg implicitly assigns old *ptr value to "old"
> when cmpxchg fails, enabling further code simplifications.
>
> No functional change intended.
Applied as:
https://git.kernel.org/pub/scm/linux/kernel/git/crng/random.git/commit/?id=6a66e096619e3a737297eb2f9f535a287af43a95
Thanks for the patch.
Jason
prev parent reply other threads:[~2022-07-16 18:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-14 18:28 [PATCH] random: Use try_cmpxchg in _credit_init_bits Uros Bizjak
2022-07-16 18:29 ` Jason A. Donenfeld [this message]
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