hwmon: (coretemp) Convert to hotplug state machine

Install the callbacks via the state machine. Setup and teardown are handled
by the hotplug core.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-hwmon@vger.kernel.org
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: rt@linuxtronix.de
Cc: Guenter Roeck <linux@roeck-us.net>
Link: http://lkml.kernel.org/r/20161117183541.8588-5-bigeasy@linutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index 1bcc90a..984c023 100644 (file)
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -649,7 +649,7 @@ static void coretemp_device_remove(unsigned int cpu)
        mutex_unlock(&pdev_list_mutex);
 }
 
-static void get_core_online(unsigned int cpu)
+static int coretemp_cpu_online(unsigned int cpu)
 {
        struct platform_device *pdev = coretemp_get_pdev(cpu);
        struct cpuinfo_x86 *c = &cpu_data(cpu);
@@ -662,12 +662,12 @@ static void get_core_online(unsigned int cpu)
         * without thermal sensors will be filtered out.
         */
        if (!cpu_has(c, X86_FEATURE_DTHERM))
-               return;
+               return 0;
 
        if (!pdev) {
                /* Check the microcode version of the CPU */
                if (chk_ucode_version(cpu))
-                       return;
+                       return 0;
 
                /*
                 * Alright, we have DTS support.
@@ -677,7 +677,7 @@ static void get_core_online(unsigned int cpu)
                 */
                err = coretemp_device_add(cpu);
                if (err)
-                       return;
+                       return 0;
 
                pdev = coretemp_get_pdev(cpu);
                /*
@@ -697,9 +697,10 @@ static void get_core_online(unsigned int cpu)
                coretemp_add_core(pdev, cpu, 0);
 
        cpumask_set_cpu(cpu, &pdata->cpumask);
+       return 0;
 }
 
-static void put_core_offline(unsigned int cpu)
+static int coretemp_cpu_offline(unsigned int cpu)
 {
        struct platform_device *pdev = coretemp_get_pdev(cpu);
        struct platform_data *pd;
@@ -708,12 +709,12 @@ static void put_core_offline(unsigned int cpu)
 
        /* If the physical CPU device does not exist, just return */
        if (!pdev)
-               return;
+               return 0;
 
        /* The core id is too big, just return */
        indx = TO_ATTR_NO(cpu);
        if (indx > MAX_CORE_DATA - 1)
-               return;
+               return 0;
 
        pd = platform_get_drvdata(pdev);
        tdata = pd->core_data[indx];
@@ -742,7 +743,7 @@ static void put_core_offline(unsigned int cpu)
         */
        if (cpumask_empty(&pd->cpumask)) {
                coretemp_device_remove(cpu);
-               return;
+               return 0;
        }
        /*
         * Check whether this core is the target for the package
@@ -755,38 +756,19 @@ static void put_core_offline(unsigned int cpu)
                tdata->cpu = target;
                mutex_unlock(&tdata->update_lock);
        }
+       return 0;
 }
-
-static int coretemp_cpu_callback(struct notifier_block *nfb,
-                                unsigned long action, void *hcpu)
-{
-       unsigned int cpu = (unsigned long) hcpu;
-
-       switch (action) {
-       case CPU_ONLINE:
-       case CPU_DOWN_FAILED:
-               get_core_online(cpu);
-               break;
-       case CPU_DOWN_PREPARE:
-               put_core_offline(cpu);
-               break;
-       }
-       return NOTIFY_OK;
-}
-
-static struct notifier_block coretemp_cpu_notifier __refdata = {
-       .notifier_call = coretemp_cpu_callback,
-};
-
 static const struct x86_cpu_id __initconst coretemp_ids[] = {
        { X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_DTHERM },
        {}
 };
 MODULE_DEVICE_TABLE(x86cpu, coretemp_ids);
 
+static enum cpuhp_state coretemp_hp_online;
+
 static int __init coretemp_init(void)
 {
-       int i, err;
+       int err;
 
        /*
         * CPUID.06H.EAX[0] indicates whether the CPU has thermal
@@ -798,52 +780,42 @@ static int __init coretemp_init(void)
 
        err = platform_driver_register(&coretemp_driver);
        if (err)
-               goto exit;
+               return err;
 
-       cpu_notifier_register_begin();
-       for_each_online_cpu(i)
-               get_core_online(i);
+       get_online_cpus();
+       err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hwmon/coretemp:online",
+                               coretemp_cpu_online, coretemp_cpu_offline);
+       if (err < 0)
+               goto exit_driver_unreg;
+       coretemp_hp_online = err;
 
 #ifndef CONFIG_HOTPLUG_CPU
        if (list_empty(&pdev_list)) {
-               cpu_notifier_register_done();
                err = -ENODEV;
-               goto exit_driver_unreg;
+               goto exit_hp_unreg;
        }
 #endif
-
-       __register_hotcpu_notifier(&coretemp_cpu_notifier);
-       cpu_notifier_register_done();
+       put_online_cpus();
        return 0;
 
 #ifndef CONFIG_HOTPLUG_CPU
+exit_hp_unreg:
+       cpuhp_remove_state(coretemp_hp_online);
+       put_online_cpus();
+#endif
 exit_driver_unreg:
        platform_driver_unregister(&coretemp_driver);
-#endif
-exit:
        return err;
 }
+module_init(coretemp_init)
 
 static void __exit coretemp_exit(void)
 {
-       struct pdev_entry *p, *n;
-
-       cpu_notifier_register_begin();
-       __unregister_hotcpu_notifier(&coretemp_cpu_notifier);
-       mutex_lock(&pdev_list_mutex);
-       list_for_each_entry_safe(p, n, &pdev_list, list) {
-               platform_device_unregister(p->pdev);
-               list_del(&p->list);
-               kfree(p);
-       }
-       mutex_unlock(&pdev_list_mutex);
-       cpu_notifier_register_done();
+       cpuhp_remove_state(coretemp_hp_online);
        platform_driver_unregister(&coretemp_driver);
 }
+module_exit(coretemp_exit)
 
 MODULE_AUTHOR("Rudolf Marek <r.marek@assembler.cz>");
 MODULE_DESCRIPTION("Intel Core temperature monitor");
 MODULE_LICENSE("GPL");
-
-module_init(coretemp_init)
-module_exit(coretemp_exit)