linux-kernel - Re: [PATCH V2] acpi-cpufreq: replace per_cpu with driver

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Message-ID: <20150708045103.GA19130@linux>
Date:	Wed, 8 Jul 2015 10:21:03 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	Pan Xinhui <xinhuix.pan@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-pm@...r.kernel.org, rjw@...ysocki.net,
	"mnipxh@....com" <mnipxh@....com>,
	"yanmin_zhang@...ux.intel.com" <yanmin_zhang@...ux.intel.com>
Subject: Re: [PATCH V2] acpi-cpufreq: replace per_cpu with driver_data of
 policy

Hi Dmitry,

On 07-07-15, 10:11, Dmitry Torokhov wrote:
> > +	data = policy->driver_data;
> > +	cpufreq_cpu_put(policy);
> 
> If we put policy here can we guarantee that memory pointed to by data
> stays valid? Shoudln't we issue cpufreq_cpu_put(policy) after we done
> assessing the pointer?

Ideally yes, you are right. But this was a special case as a callback
of the cpufreq-driver is being called and any such issues must be
handled at the core level, it at all they are relevant.

So probably we can do cpufreq_cpu_put() as soon as we have used it.

-- 
viresh
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