cpufreq: Add policy create/remove notifiers back

This effectively reverts some changes made by commit f9f41e3ef99
("cpufreq: Remove policy create/remove notifiers").

We have a new use case for policy create/remove notifiers (for
allocating/freeing QoS requests per policy), so add them back.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 16 insertions, 1 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 8dda62367816..c13dcb59b30c 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1266,7 +1266,17 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy)
                                    DEV_PM_QOS_MAX_FREQUENCY);
         dev_pm_qos_remove_notifier(dev, &policy->nb_min,
                                    DEV_PM_QOS_MIN_FREQUENCY);
-        dev_pm_qos_remove_request(policy->max_freq_req);
+
+        if (policy->max_freq_req) {
+                /*
+                 * CPUFREQ_CREATE_POLICY notification is sent only after
+                 * successfully adding max_freq_req request.
+                 */
+                blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
+                                             CPUFREQ_REMOVE_POLICY, policy);
+                dev_pm_qos_remove_request(policy->max_freq_req);
+        }
+
         dev_pm_qos_remove_request(policy->min_freq_req);
         kfree(policy->min_freq_req);
 
@@ -1391,6 +1401,9 @@ static int cpufreq_online(unsigned int cpu)
                                 ret);
                         goto out_destroy_policy;
                 }
+
+                blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
+                                CPUFREQ_CREATE_POLICY, policy);
         }
 
         if (cpufreq_driver->get && has_target()) {
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 536a049d7ecc..afc10384a681 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -458,6 +458,8 @@ static inline void cpufreq_resume(void) {}
 /* Policy Notifiers  */
 #define CPUFREQ_ADJUST                  (0)
 #define CPUFREQ_NOTIFY                  (1)
+#define CPUFREQ_CREATE_POLICY           (2)
+#define CPUFREQ_REMOVE_POLICY           (3)
 
 #ifdef CONFIG_CPU_FREQ
 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);