cpufreq: Separate CPU device registration from CPU online

To separate the CPU online interface from the CPU device
registration, split cpufreq_online() out of cpufreq_add_dev()
and make cpufreq_cpu_callback() call the former, while
cpufreq_add_dev() itself will only be used as the CPU device
addition subsystem interface callback.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Suggested-by: Russell King <linux@arm.linux.org.uk>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 0618522d4863ce1e85a0657c157cc53ac9804632..0d46b557c016155f18ffefc0389af9000a320938 100644 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1191,36 +1191,15 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
        kfree(policy);
 }
 
-/**
- * cpufreq_add_dev - add a CPU device
- *
- * Adds the cpufreq interface for a CPU device.
- *
- * The Oracle says: try running cpufreq registration/unregistration concurrently
- * with with cpu hotplugging and all hell will break loose. Tried to clean this
- * mess up, but more thorough testing is needed. - Mathieu
- */
-static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
+static int cpufreq_online(unsigned int cpu)
 {
-       unsigned int j, cpu = dev->id;
-       int ret;
        struct cpufreq_policy *policy;
-       unsigned long flags;
        bool recover_policy;
+       unsigned long flags;
+       unsigned int j;
+       int ret;
 
-       pr_debug("adding CPU %u\n", cpu);
-
-       if (cpu_is_offline(cpu)) {
-               /*
-                * Only possible if we are here from the subsys_interface add
-                * callback.  A hotplug notifier will follow and we will handle
-                * it as CPU online then.  For now, just create the sysfs link,
-                * unless there is no policy or the link is already present.
-                */
-               policy = per_cpu(cpufreq_cpu_data, cpu);
-               return policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
-                       ? add_cpu_dev_symlink(policy, cpu) : 0;
-       }
+       pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
 
        /* Check if this CPU already has a policy to manage it */
        policy = per_cpu(cpufreq_cpu_data, cpu);
@@ -1377,6 +1356,35 @@ out_free_policy:
        return ret;
 }
 
+/**
+ * cpufreq_add_dev - the cpufreq interface for a CPU device.
+ * @dev: CPU device.
+ * @sif: Subsystem interface structure pointer (not used)
+ */
+static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
+{
+       unsigned cpu = dev->id;
+       int ret;
+
+       dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
+
+       if (cpu_online(cpu)) {
+               ret = cpufreq_online(cpu);
+       } else {
+               /*
+                * A hotplug notifier will follow and we will handle it as CPU
+                * online then.  For now, just create the sysfs link, unless
+                * there is no policy or the link is already present.
+                */
+               struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
+
+               ret = policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
+                       ? add_cpu_dev_symlink(policy, cpu) : 0;
+       }
+
+       return ret;
+}
+
 static void cpufreq_offline_prepare(unsigned int cpu)
 {
        struct cpufreq_policy *policy;
@@ -2340,27 +2348,23 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb,
                                        unsigned long action, void *hcpu)
 {
        unsigned int cpu = (unsigned long)hcpu;
-       struct device *dev;
 
-       dev = get_cpu_device(cpu);
-       if (dev) {
-               switch (action & ~CPU_TASKS_FROZEN) {
-               case CPU_ONLINE:
-                       cpufreq_add_dev(dev, NULL);
-                       break;
+       switch (action & ~CPU_TASKS_FROZEN) {
+       case CPU_ONLINE:
+               cpufreq_online(cpu);
+               break;
 
-               case CPU_DOWN_PREPARE:
-                       cpufreq_offline_prepare(cpu);
-                       break;
+       case CPU_DOWN_PREPARE:
+               cpufreq_offline_prepare(cpu);
+               break;
 
-               case CPU_POST_DEAD:
-                       cpufreq_offline_finish(cpu);
-                       break;
+       case CPU_POST_DEAD:
+               cpufreq_offline_finish(cpu);
+               break;
 
-               case CPU_DOWN_FAILED:
-                       cpufreq_add_dev(dev, NULL);
-                       break;
-               }
+       case CPU_DOWN_FAILED:
+               cpufreq_online(cpu);
+               break;
        }
        return NOTIFY_OK;
 }