linux-kernel - Re: [PATCH] dmaengine:idxd: Use local64_try_cmpxchg in perfmon_pmu_event

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: <169091550434.69468.5073669723336926533.b4-ty@kernel.org>
Date:   Wed, 02 Aug 2023 00:15:04 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org,
        Uros Bizjak <ubizjak@...il.com>
Cc:     Fenghua Yu <fenghua.yu@...el.com>,
        Dave Jiang <dave.jiang@...el.com>
Subject: Re: [PATCH] dmaengine:idxd: Use local64_try_cmpxchg in
 perfmon_pmu_event_update


On Mon, 03 Jul 2023 16:52:37 +0200, Uros Bizjak wrote:
> Use local64_try_cmpxchg instead of local64_cmpxchg (*ptr, old, new) == old
> in perfmon_pmu_event_update.  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. There is no need to re-read the value in the loop.
> 
> [...]

Applied, thanks!

[1/1] dmaengine:idxd: Use local64_try_cmpxchg in perfmon_pmu_event_update
      commit: cae701b9ccf128edea26982f73178087fc3ad180

Best regards,
-- 
~Vinod