linux-kernel - Re: [RFC PATCH v3] locking/atomic: Implement atomic{,64,_long}_{fetch_,}{andnot_or}{,_relaxed,_acquire,

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

Message-ID: <CAK8P3a3ru0VSYLohoFOd=P=Fjb8BS=1qpMGSf4jdxF4oxmH-ag@mail.gmail.com>
Date:   Thu, 29 Jul 2021 13:43:41 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Will Deacon <will@...nel.org>
Cc:     Rui Wang <wangrui@...ngson.cn>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>, Arnd Bergmann <arnd@...db.de>,
        Waiman Long <longman@...hat.com>,
        Boqun Feng <boqun.feng@...il.com>, Guo Ren <guoren@...nel.org>,
        linux-arch <linux-arch@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Rui Wang <r@....cc>, Xuefeng Li <lixuefeng@...ngson.cn>,
        Huacai Chen <chenhuacai@...il.com>,
        Jiaxun Yang <jiaxun.yang@...goat.com>,
        Huacai Chen <chenhuacai@...ngson.cn>,
        kernel test robot <lkp@...el.com>
Subject: Re: [RFC PATCH v3] locking/atomic: Implement atomic{,64,_long}_{fetch_,}{andnot_or}{,_relaxed,_acquire,_release}()

On Thu, Jul 29, 2021 at 11:56 AM Will Deacon <will@...nel.org> wrote:
> On Thu, Jul 29, 2021 at 05:30:03PM +0800, Rui Wang wrote:
> > This patch introduce a new atomic primitive andnot_or:
>
> Please see my other comments on the other patches you posted:
>
> https://lore.kernel.org/r/20210729093923.GD21151@willie-the-truck
>
> Overall, I'm not thrilled to bits by extending the atomics API with
> operations that cannot be implemented efficiently on any (?) architectures
> and are only used by the qspinlock slowpath on machines with more than 16K
> CPUs.

Wouldn't this also help improve set_mask_bits()? That one at least has
a handful of users in the kernel.

       Arnd