linux-kernel - Re: [PATCH v2] block/rq_qos: Use atomic_try_cmpxchg in atomic_inc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <165765839842.44219.4233753152017615209.b4-ty@kernel.dk>
Date:   Tue, 12 Jul 2022 14:39:58 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     ubizjak@...il.com, linux-kernel@...r.kernel.org,
        linux-block@...r.kernel.org
Subject: Re: [PATCH v2] block/rq_qos: Use atomic_try_cmpxchg in atomic_inc_below

On Tue, 12 Jul 2022 17:05:47 +0200, Uros Bizjak wrote:
> Use atomic_try_cmpxchg instead of atomic_cmpxchg (*ptr, old, new) == old in
> atomic_inc_below. 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, atomic_try_cmpxchg implicitly assigns old *ptr value to "old" when
> cmpxchg fails, enabling further code simplifications.
> 
> [...]

Applied, thanks!

[1/1] block/rq_qos: Use atomic_try_cmpxchg in atomic_inc_below
      commit: f4b1e27db49c8b985b116aa99481b4c6a4342ed4

Best regards,
-- 
Jens Axboe