powercap/intel rapl: Convert to hotplug state machine

Install the callbacks via the state machine as a first step. The init/exit
code is a duplicate of the hotplug code. This is cleaned up in a
consecutive patch.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
index 79b1e041f2ec2a6cc03b6c8628367c4f0a7eb443..de5cf22371f5839b9dc163ed603a45a6cea1e493 100644 (file)
--- a/drivers/powercap/intel_rapl.c
+++ b/drivers/powercap/intel_rapl.c
@@ -1603,50 +1603,48 @@ err_free_package:
  * associated domains. Cooling devices are handled accordingly at
  * per-domain level.
  */
-static int rapl_cpu_callback(struct notifier_block *nfb,
-                               unsigned long action, void *hcpu)
+static int rapl_cpu_online(unsigned int cpu)
+{
+       struct rapl_package *rp;
+       int phy_package_id;
+
+       phy_package_id = topology_physical_package_id(cpu);
+
+       rp = find_package_by_id(phy_package_id);
+       if (rp)
+               rp->nr_cpus++;
+       else
+               rapl_add_package(cpu);
+       return 0;
+}
+
+static int rapl_cpu_down_prep(unsigned int cpu)
 {
-       unsigned long cpu = (unsigned long)hcpu;
        int phy_package_id;
        struct rapl_package *rp;
        int lead_cpu;
 
        phy_package_id = topology_physical_package_id(cpu);
-       switch (action) {
-       case CPU_ONLINE:
-       case CPU_ONLINE_FROZEN:
-       case CPU_DOWN_FAILED:
-       case CPU_DOWN_FAILED_FROZEN:
-               rp = find_package_by_id(phy_package_id);
-               if (rp)
-                       ++rp->nr_cpus;
-               else
-                       rapl_add_package(cpu);
-               break;
-       case CPU_DOWN_PREPARE:
-       case CPU_DOWN_PREPARE_FROZEN:
-               rp = find_package_by_id(phy_package_id);
-               if (!rp)
-                       break;
-               if (--rp->nr_cpus == 0)
-                       rapl_remove_package(rp);
-               else if (cpu == rp->lead_cpu) {
-                       /* choose another active cpu in the package */
-                       lead_cpu = cpumask_any_but(topology_core_cpumask(cpu), cpu);
-                       if (lead_cpu < nr_cpu_ids)
-                               rp->lead_cpu = lead_cpu;
-                       else /* should never go here */
-                               pr_err("no active cpu available for package %d\n",
-                                       phy_package_id);
+       rp = find_package_by_id(phy_package_id);
+       if (!rp)
+               return 0;
+       if (--rp->nr_cpus == 0) {
+               rapl_remove_package(rp);
+       } else if (cpu == rp->lead_cpu) {
+               /* choose another active cpu in the package */
+               lead_cpu = cpumask_any_but(topology_core_cpumask(cpu), cpu);
+               if (lead_cpu < nr_cpu_ids) {
+                       rp->lead_cpu = lead_cpu;
+               } else {
+                       /* should never go here */
+                       pr_err("no active cpu available for package %d\n",
+                              phy_package_id);
                }
        }
-
-       return NOTIFY_OK;
+       return 0;
 }
 
-static struct notifier_block rapl_cpu_notifier = {
-       .notifier_call = rapl_cpu_callback,
-};
+static enum cpuhp_state pcap_rapl_online;
 
 static int __init rapl_init(void)
 {
@@ -1663,36 +1661,42 @@ static int __init rapl_init(void)
 
        rapl_defaults = (struct rapl_defaults *)id->driver_data;
 
-       cpu_notifier_register_begin();
-
        /* prevent CPU hotplug during detection */
        get_online_cpus();
        ret = rapl_detect_topology();
        if (ret)
-               goto done;
+               goto err;
 
        if (rapl_register_powercap()) {
-               rapl_cleanup_data();
                ret = -ENODEV;
-               goto done;
+               goto err_cleanup;
        }
-       __register_hotcpu_notifier(&rapl_cpu_notifier);
-done:
+       ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+                                       "powercap/rapl:online",
+                                       rapl_cpu_online, rapl_cpu_down_prep);
+       if (ret < 0)
+               goto err_unreg;
+       pcap_rapl_online = ret;
        put_online_cpus();
-       cpu_notifier_register_done();
+       return 0;
+
+err_unreg:
+       rapl_unregister_powercap();
 
+err_cleanup:
+       rapl_cleanup_data();
+err:
+       put_online_cpus();
        return ret;
 }
 
 static void __exit rapl_exit(void)
 {
-       cpu_notifier_register_begin();
        get_online_cpus();
-       __unregister_hotcpu_notifier(&rapl_cpu_notifier);
+       cpuhp_remove_state(pcap_rapl_online);
        rapl_unregister_powercap();
        rapl_cleanup_data();
        put_online_cpus();
-       cpu_notifier_register_done();
 }
 
 module_init(rapl_init);