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cpufreq: Avoid calling cpufreq_verify_current_freq() from handle_update() 

On some occasions cpufreq_verify_current_freq() schedules a work whose
callback is handle_update(), which further calls cpufreq_update_policy()
which may end up calling cpufreq_verify_current_freq() again.

On the other hand, when cpufreq_update_policy() is called from
handle_update(), the pointer to the cpufreq policy is already
available, but cpufreq_cpu_acquire() is still called to get it in
cpufreq_update_policy(), which should be avoided as well.

To fix these issues, create a new helper, refresh_frequency_limits(),
and make both handle_update() call it cpufreq_update_policy().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Rename reeval_frequency_limits() as refresh_frequency_limits() ]
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Viresh Kumar 2019-06-20 08:35:50 +05:30 committed by Rafael J. Wysocki
parent 5980752e6e
commit 70a59fde6e
1 changed files with 16 additions and 10 deletions
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26
drivers/cpufreq/cpufreq.c
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@ -1115,13 +1115,25 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cp
return ret;
}
static void refresh_frequency_limits(struct cpufreq_policy *policy)
{
struct cpufreq_policy new_policy = *policy;
pr_debug("updating policy for CPU %u\n", policy->cpu);
new_policy.min = policy->user_policy.min;
new_policy.max = policy->user_policy.max;
cpufreq_set_policy(policy, &new_policy);
}
static void handle_update(struct work_struct *work)
{
struct cpufreq_policy *policy =
container_of(work, struct cpufreq_policy, update);
unsigned int cpu = policy->cpu;
pr_debug("handle_update for cpu %u called\n", cpu);
cpufreq_update_policy(cpu);
pr_debug("handle_update for cpu %u called\n", policy->cpu);
refresh_frequency_limits(policy);
}
static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
@ -2376,7 +2388,6 @@ int cpufreq_set_policy(struct cpufreq_policy *policy,
void cpufreq_update_policy(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
struct cpufreq_policy new_policy;
if (!policy)
return;
@ -2389,12 +2400,7 @@ void cpufreq_update_policy(unsigned int cpu)
(cpufreq_suspended || WARN_ON(!cpufreq_verify_current_freq(policy, false))))
goto unlock;
pr_debug("updating policy for CPU %u\n", cpu);
memcpy(&new_policy, policy, sizeof(*policy));
new_policy.min = policy->user_policy.min;
new_policy.max = policy->user_policy.max;
cpufreq_set_policy(policy, &new_policy);
refresh_frequency_limits(policy);
unlock:
cpufreq_cpu_release(policy);