netdev - Re: [PATCH net-next] net: stmmac: optimize locking around PTP clock reads

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]

Date:   Tue, 08 Feb 2022 04:10:08 +0000
From:   patchwork-bot+netdevbpf@...nel.org
To:     Yannick Vignon <yannick.vignon@....nxp.com>
Cc:     peppe.cavallaro@...com, alexandre.torgue@...s.st.com,
        joabreu@...opsys.com, davem@...emloft.net, kuba@...nel.org,
        mcoquelin.stm32@...il.com, netdev@...r.kernel.org,
        olteanv@...il.com, xiaoliang.yang_1@....com, mingkai.hu@....com,
        qiangqing.zhang@....com, sebastien.laveze@....com,
        yannick.vignon@....com
Subject: Re: [PATCH net-next] net: stmmac: optimize locking around PTP clock reads

Hello:

This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba@...nel.org>:

On Fri,  4 Feb 2022 14:55:44 +0100 you wrote:
> From: Yannick Vignon <yannick.vignon@....com>
> 
> Reading the PTP clock is a simple operation requiring only 3 register
> reads. Under a PREEMPT_RT kernel, protecting those reads by a spin_lock is
> counter-productive: if the 2nd task preempting the 1st has a higher prio
> but needs to read time as well, it will require 2 context switches, which
> will pretty much always be more costly than just disabling preemption for
> the duration of the reads. Moreover, with the code logic recently added
> to get_systime(), disabling preemption is not even required anymore:
> reads and writes just need to be protected from each other, to prevent a
> clock read while the clock is being updated.
> 
> [...]

Here is the summary with links:
  - [net-next] net: stmmac: optimize locking around PTP clock reads
    https://git.kernel.org/netdev/net-next/c/642436a1ad34

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html