[patch 23/40] cpufreq: Convert to hotplug state machine

[Thomas Gleixner]

Straight forward conversion to state machine callbacks w/o fixing the
obvious brokeness of the asymetric state invocations.

Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
 drivers/cpufreq/cpufreq_stats.c |   55 +++++++++-------------------------------
 include/linux/cpuhotplug.h      |    2 +
 2 files changed, 15 insertions(+), 42 deletions(-)

Index: linux-2.6/drivers/cpufreq/cpufreq_stats.c
===================================================================
--- linux-2.6.orig/drivers/cpufreq/cpufreq_stats.c
+++ linux-2.6/drivers/cpufreq/cpufreq_stats.c
@@ -167,7 +167,7 @@ static int freq_table_get_index(struct c
 /* should be called late in the CPU removal sequence so that the stats
  * memory is still available in case someone tries to use it.
  */
-static void cpufreq_stats_free_table(unsigned int cpu)
+static int cpufreq_stats_free_table(unsigned int cpu)
 {
        struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
        if (stat) {
@@ -175,18 +175,20 @@ static void cpufreq_stats_free_table(uns
                kfree(stat);
        }
        per_cpu(cpufreq_stats_table, cpu) = NULL;
+       return 0;
 }
 
 /* must be called early in the CPU removal sequence (before
  * cpufreq_remove_dev) so that policy is still valid.
  */
-static void cpufreq_stats_free_sysfs(unsigned int cpu)
+static int cpufreq_stats_free_sysfs(unsigned int cpu)
 {
        struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
        if (policy && policy->cpu == cpu)
                sysfs_remove_group(&policy->kobj, &stats_attr_group);
        if (policy)
                cpufreq_cpu_put(policy);
+       return 0;
 }
 
 static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
@@ -316,35 +318,6 @@ static int cpufreq_stat_notifier_trans(s
        return 0;
 }
 
-static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
-                                              unsigned long action,
-                                              void *hcpu)
-{
-       unsigned int cpu = (unsigned long)hcpu;
-
-       switch (action) {
-       case CPU_ONLINE:
-       case CPU_ONLINE_FROZEN:
-               cpufreq_update_policy(cpu);
-               break;
-       case CPU_DOWN_PREPARE:
-       case CPU_DOWN_PREPARE_FROZEN:
-               cpufreq_stats_free_sysfs(cpu);
-               break;
-       case CPU_DEAD:
-       case CPU_DEAD_FROZEN:
-               cpufreq_stats_free_table(cpu);
-               break;
-       }
-       return NOTIFY_OK;
-}
-
-/* priority=1 so this will get called before cpufreq_remove_dev */
-static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
-       .notifier_call = cpufreq_stat_cpu_callback,
-       .priority = 1,
-};
-
 static struct notifier_block notifier_policy_block = {
        .notifier_call = cpufreq_stat_notifier_policy
 };
@@ -364,18 +337,19 @@ static int __init cpufreq_stats_init(voi
        if (ret)
                return ret;
 
-       register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
-       for_each_online_cpu(cpu)
-               cpufreq_update_policy(cpu);
+       /* Install callbacks. Core will call them for each online cpu */
+       cpuhp_setup_state(CPUHP_CPUFREQ_DEAD, NULL, cpufreq_stats_free_table);
+       /* CHECKME: This is pretty broken versus failures in up/down! */
+       cpuhp_setup_state(CPUHP_CPUFREQ_ONLINE, cpufreq_update_policy,
+                         cpufreq_stats_free_sysfs);
 
        ret = cpufreq_register_notifier(&notifier_trans_block,
                                CPUFREQ_TRANSITION_NOTIFIER);
        if (ret) {
                cpufreq_unregister_notifier(&notifier_policy_block,
                                CPUFREQ_POLICY_NOTIFIER);
-               unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
-               for_each_online_cpu(cpu)
-                       cpufreq_stats_free_table(cpu);
+               cpuhp_uninstall_callbacks(cpufreq_stats_cbs,
+                                         ARRAY_SIZE(cpufreq_stats_cbs));
                return ret;
        }
 
@@ -389,11 +363,8 @@ static void __exit cpufreq_stats_exit(vo
                        CPUFREQ_POLICY_NOTIFIER);
        cpufreq_unregister_notifier(&notifier_trans_block,
                        CPUFREQ_TRANSITION_NOTIFIER);
-       unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
-       for_each_online_cpu(cpu) {
-               cpufreq_stats_free_table(cpu);
-               cpufreq_stats_free_sysfs(cpu);
-       }
+       cpuhp_uninstall_callbacks(cpufreq_stats_cbs,
+                                 ARRAY_SIZE(cpufreq_stats_cbs));
 }
 
 MODULE_AUTHOR("Zou Nan hai <nanhai....@intel.com>");
Index: linux-2.6/include/linux/cpuhotplug.h
===================================================================
--- linux-2.6.orig/include/linux/cpuhotplug.h
+++ linux-2.6/include/linux/cpuhotplug.h
@@ -14,6 +14,7 @@ enum cpuhp_states {
        CPUHP_WORKQUEUE_PREP,
        CPUHP_NOTIFY_PREPARE,
        CPUHP_NOTIFY_DEAD,
+       CPUHP_CPUFREQ_DEAD,
        CPUHP_SCHED_DEAD,
        CPUHP_BRINGUP_CPU,
        CPUHP_AP_OFFLINE,
@@ -31,6 +32,7 @@ enum cpuhp_states {
        CPUHP_PERF_ONLINE,
        CPUHP_SCHED_MIGRATE_ONLINE,
        CPUHP_WORKQUEUE_ONLINE,
+       CPUHP_CPUFREQ_ONLINE,
        CPUHP_NOTIFY_ONLINE,
        CPUHP_NOTIFY_DOWN_PREPARE,
        CPUHP_PERF_X86_UNCORE_ONLINE,


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