Re: [PATCH] cpufreq: acpi: policy->driver_data can't be NULL in ->exit()

From: Viresh Kumar
Date: Wed Mar 30 2016 - 07:21:13 EST


On 30-03-16, 13:15, Rafael J. Wysocki wrote:
> On Wed, Mar 30, 2016 at 6:24 AM, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
> > Its always set by ->init() and so it will always be there in ->exit().
> > There is no need to have a special check for just that.
>
> I'm not sure what happens if there are two (or more) CPUs in the policy, though.
>
> That case is almost certainly handled incorrectly here (or rather not
> handled at all), but it may just happen to sort of work, because the
> first exiting CPU will clear driver_data and the second one will
> notice that it is NULL now. Of course, that still is racy with
> respect to governors etc, but I'd rather fix the driver properly.

Sorry, I probably didn't understood your comments properly.

But, the core will call ->exit() only for the last exiting CPU. So,
driver_data will never be NULL.

--
viresh