[Question] Why is there a restriction on the policy->rwsem & CPUFREQ_GOV_POLICY_EXIT ?

[Prarit Bhargava <prarit@redhat.com>]

I'm debugging a race/locking issue in the store_scaling_governor path and
came across the following restriction on using a semaphore in the
cpufreq_policy struct defined in include/linux/cpufreq.h :

         * Additional rules:
         * - Lock should not be held across
         *     __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);

	struct rw_semaphore	rwsem;

I'm not completely familiar with this code and am wondering why the
restriction is in place?  Is there a worry about the module_put() in
__cpufreq_governor()?

Thanks,

P.