Re: [PATCH 10/18] cpufreq: Don't allow updating inactive-policies from sysfs

[Saravana Kannan <skannan@codeaurora.org>]

On 01/27/2015 12:36 AM, Viresh Kumar wrote:
> Later commits would change the way policies are managed today. Policies wouldn't
> be freed on cpu hotplug (currently they aren't freed on suspend), and while the
> CPU is offline, the sysfs cpufreq files would still be present.
>
> User may accidentally try to update the sysfs files in following directory:
> '/sys/devices/system/cpu/cpuX/cpufreq/'. And that would result in undefined
> behavior as policy wouldn't be active then.
>
> To disallow such accesses, sense if a policy is active or not while doing such
> operations. This can be done easily by getting the policy again with
> cpufreq_cpu_get_raw(), as that would traverse the list of active policies.
>
> Apart from updating the store() routine, we also update __cpufreq_get() which
> can call cpufreq_out_of_sync(). The later routine tries to update policy->cur
> and start notifying kernel about it.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---

I'm okay with the idea of this patch for now. I'll argue against this 
after this series goes in as it'll need more non-trivial changes before 
this idea of this patch can be removed.

But not acking it because I expect the code to change after combining 
active/inactive list.

-Saravana

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