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>

1 files changed, 16 insertions, 10 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index cba9c9e1bd0f..ceb57af15ca0 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -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);