Merge branch 'pm-cpufreq'

* pm-cpufreq:
  cpufreq: Acquire the lock in cpufreq_policy_restore() for reading
  cpufreq: Prevent problems in update_policy_cpu() if last_cpu == new_cpu
  cpufreq: Restructure if/else block to avoid unintended behavior
  cpufreq: Fix crash in cpufreq-stats during suspend/resume

1 files changed, 32 insertions, 17 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 5a64f66d36e0..43c24aa756f6 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -906,11 +906,11 @@ static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
         struct cpufreq_policy *policy;
         unsigned long flags;
 
-        write_lock_irqsave(&cpufreq_driver_lock, flags);
+        read_lock_irqsave(&cpufreq_driver_lock, flags);
 
         policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
 
-        write_unlock_irqrestore(&cpufreq_driver_lock, flags);
+        read_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
         return policy;
 }
@@ -947,6 +947,21 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy)
         kfree(policy);
 }
 
+static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
+{
+        if (cpu == policy->cpu)
+                return;
+
+        policy->last_cpu = policy->cpu;
+        policy->cpu = cpu;
+
+#ifdef CONFIG_CPU_FREQ_TABLE
+        cpufreq_frequency_table_update_policy_cpu(policy);
+#endif
+        blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
+                        CPUFREQ_UPDATE_POLICY_CPU, policy);
+}
+
 static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
                              bool frozen)
 {
@@ -1000,7 +1015,18 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
         if (!policy)
                 goto nomem_out;
 
-        policy->cpu = cpu;
+
+        /*
+         * In the resume path, since we restore a saved policy, the assignment
+         * to policy->cpu is like an update of the existing policy, rather than
+         * the creation of a brand new one. So we need to perform this update
+         * by invoking update_policy_cpu().
+         */
+        if (frozen && cpu != policy->cpu)
+                update_policy_cpu(policy, cpu);
+        else
+                policy->cpu = cpu;
+
         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
         cpumask_copy(policy->cpus, cpumask_of(cpu));
 
@@ -1092,18 +1118,6 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
         return __cpufreq_add_dev(dev, sif, false);
 }
 
-static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
-{
-        policy->last_cpu = policy->cpu;
-        policy->cpu = cpu;
-
-#ifdef CONFIG_CPU_FREQ_TABLE
-        cpufreq_frequency_table_update_policy_cpu(policy);
-#endif
-        blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
-                        CPUFREQ_UPDATE_POLICY_CPU, policy);
-}
-
 static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
                                            unsigned int old_cpu, bool frozen)
 {
@@ -1182,8 +1196,9 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
                 cpumask_clear_cpu(cpu, policy->cpus);
         unlock_policy_rwsem_write(cpu);
 
-        if (cpu != policy->cpu && !frozen) {
-                sysfs_remove_link(&dev->kobj, "cpufreq");
+        if (cpu != policy->cpu) {
+                if (!frozen)
+                        sysfs_remove_link(&dev->kobj, "cpufreq");
         } else if (cpus > 1) {
 
                 new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen);