linux-kernel - Re: [PATCH v3 1/3] cpufreq: mediatek: using global lock avoid race condition

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Message-ID: <20250219054209.erwfp7sgzchaiuds@vireshk-i7>
Date: Wed, 19 Feb 2025 11:12:09 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Mark Tseng <chun-jen.tseng@...iatek.com>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>,
	MyungJoo Ham <myungjoo.ham@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Chanwoo Choi <cw00.choi@...sung.com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org,
	Project_Global_Chrome_Upstream_Group@...iatek.com
Subject: Re: [PATCH v3 1/3] cpufreq: mediatek: using global lock avoid race
 condition

On 14-02-25, 15:43, Mark Tseng wrote:
> In mtk_cpufreq_set_target() is re-enter function but the mutex lock
> decalre in mtk_cpu_dvfs_info structure for each policy. It should
> change to global variable for critical session avoid race condition
> with 2 or more policy.

And what exactly is the race condition here ? Can you please explain that ?
Since the struct mtk_cpu_dvfs_info instance is per-policy, I don't think there
is any race here.

The lock was introduced earlier to avoid a potential race with notifiers, but it
has nothing to do with calling target simultaneously.

commit c210063b40ac ("cpufreq: mediatek: Add opp notification support")

-- 
viresh