linux-kernel - Re: [PATCH v1 02/10] platform/x86: msi-wmi-platform: Add unlocked msi_wmi_platform

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: 
 <CAGwozwE6-=9L2RTwipgHjmdQWzBAX7PxBYgJO_oGcWaHtLhoSA@mail.gmail.com>
Date: Mon, 12 May 2025 22:51:20 +0200
From: Antheas Kapenekakis <lkml@...heas.dev>
To: Kurt Borja <kuurtb@...il.com>
Cc: platform-driver-x86@...r.kernel.org, Armin Wolf <W_Armin@....de>,
	Jonathan Corbet <corbet@....net>, Hans de Goede <hdegoede@...hat.com>,
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
	Jean Delvare <jdelvare@...e.com>, Guenter Roeck <linux@...ck-us.net>,
 linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org
Subject: Re: [PATCH v1 02/10] platform/x86: msi-wmi-platform: Add unlocked
 msi_wmi_platform_query

On Mon, 12 May 2025 at 21:21, Kurt Borja <kuurtb@...il.com> wrote:
>
> On Sun May 11, 2025 at 5:44 PM -03, Antheas Kapenekakis wrote:
> > This driver requires to be able to handle transactions that perform
> > multiple WMI actions at a time. Therefore, it needs to be able to
> > lock the wmi_lock mutex for multiple operations.
> >
> > Add msi_wmi_platform_query_unlocked() to allow the caller to
> > perform the WMI query without locking the wmi_lock mutex, by
> > renaming the existing function and adding a new one that only
> > locks the mutex.
> >
> > Signed-off-by: Antheas Kapenekakis <lkml@...heas.dev>
>
> You only use msi_wmi_platform_query_unlocked() to protect the
> fan_curve/AP state right?
>
> If that's the case I think we don't need it. AFAIK sysfs reads/writes
> are already synchronized/locked, and as I mentioned in Patch 10, I don't
> think you need this variant in probe/remove either.
>
> I'd like to hear more opinions on this though.

Are sysfs reads/writes between different files of the same driver
synced? If not, it is better to lock.

I want a second opinion here too.

You are correct on probe/remove.

Antheas

> --
>  ~ Kurt