thermal/x86 pkg temp: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Replace the wrmsr/rdmrs_on_cpu() calls in the hotplug callbacks as they are
guaranteed to be invoked on the incoming/outgoing cpu.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

diff --git a/drivers/thermal/x86_pkg_temp_thermal.c b/drivers/thermal/x86_pkg_temp_thermal.c
index 13f37d212164f8a72614f2a876c21bc337677364..d93eee2f101b0aeede2049f515154687df9428db 100644 (file)
--- a/drivers/thermal/x86_pkg_temp_thermal.c
+++ b/drivers/thermal/x86_pkg_temp_thermal.c
@@ -79,6 +79,9 @@ static DEFINE_SPINLOCK(pkg_temp_lock);
 /* Protects zone operation in the work function against hotplug removal */
 static DEFINE_MUTEX(thermal_zone_mutex);
 
+/* The dynamically assigned cpu hotplug state for module_exit() */
+static enum cpuhp_state pkg_thermal_hp_state __read_mostly;
+
 /* Debug counters to show using debugfs */
 static struct dentry *debugfs;
 static unsigned int pkg_interrupt_cnt;
@@ -386,9 +389,8 @@ static int pkg_temp_thermal_device_add(unsigned int cpu)
                return err;
        }
        /* Store MSR value for package thermal interrupt, to restore at exit */
-       rdmsr_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT,
-                    &pkgdev->msr_pkg_therm_low,
-                    &pkgdev->msr_pkg_therm_high);
+       rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, pkgdev->msr_pkg_therm_low,
+             pkgdev->msr_pkg_therm_high);
 
        cpumask_set_cpu(cpu, &pkgdev->cpumask);
        spin_lock_irq(&pkg_temp_lock);
@@ -397,14 +399,14 @@ static int pkg_temp_thermal_device_add(unsigned int cpu)
        return 0;
 }
 
-static void put_core_offline(unsigned int cpu)
+static int pkg_thermal_cpu_offline(unsigned int cpu)
 {
        struct pkg_device *pkgdev = pkg_temp_thermal_get_dev(cpu);
        bool lastcpu, was_target;
        int target;
 
        if (!pkgdev)
-               return;
+               return 0;
 
        target = cpumask_any_but(&pkgdev->cpumask, cpu);
        cpumask_clear_cpu(cpu, &pkgdev->cpumask);
@@ -448,16 +450,9 @@ static void put_core_offline(unsigned int cpu)
         */
        if (lastcpu) {
                packages[topology_logical_package_id(cpu)] = NULL;
-               /*
-                * After this point nothing touches the MSR anymore. We
-                * must drop the lock to make the cross cpu call. This goes
-                * away once we move that code to the hotplug state machine.
-                */
-               spin_unlock_irq(&pkg_temp_lock);
-               wrmsr_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT,
-                            pkgdev->msr_pkg_therm_low,
-                            pkgdev->msr_pkg_therm_high);
-               spin_lock_irq(&pkg_temp_lock);
+               /* After this point nothing touches the MSR anymore. */
+               wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
+                     pkgdev->msr_pkg_therm_low, pkgdev->msr_pkg_therm_high);
        }
 
        /*
@@ -487,9 +482,10 @@ static void put_core_offline(unsigned int cpu)
        /* Final cleanup if this is the last cpu */
        if (lastcpu)
                kfree(pkgdev);
+       return 0;
 }
 
-static int get_core_online(unsigned int cpu)
+static int pkg_thermal_cpu_online(unsigned int cpu)
 {
        struct pkg_device *pkgdev = pkg_temp_thermal_get_dev(cpu);
        struct cpuinfo_x86 *c = &cpu_data(cpu);
@@ -506,27 +502,6 @@ static int get_core_online(unsigned int cpu)
        return pkg_temp_thermal_device_add(cpu);
 }
 
-static int pkg_temp_thermal_cpu_callback(struct notifier_block *nfb,
-                                unsigned long action, void *hcpu)
-{
-       unsigned int cpu = (unsigned long) hcpu;
-
-       switch (action & ~CPU_TASKS_FROZEN) {
-       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 pkg_temp_thermal_notifier __refdata = {
-       .notifier_call = pkg_temp_thermal_cpu_callback,
-};
-
 static const struct x86_cpu_id __initconst pkg_temp_thermal_ids[] = {
        { X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_PTS },
        {}
@@ -535,7 +510,7 @@ MODULE_DEVICE_TABLE(x86cpu, pkg_temp_thermal_ids);
 
 static int __init pkg_temp_thermal_init(void)
 {
-       int i;
+       int ret;
 
        if (!x86_match_cpu(pkg_temp_thermal_ids))
                return -ENODEV;
@@ -545,12 +520,13 @@ static int __init pkg_temp_thermal_init(void)
        if (!packages)
                return -ENOMEM;
 
-       cpu_notifier_register_begin();
-       for_each_online_cpu(i)
-               if (get_core_online(i))
-                       goto err_ret;
-       __register_hotcpu_notifier(&pkg_temp_thermal_notifier);
-       cpu_notifier_register_done();
+       ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "thermal/x86_pkg:online",
+                               pkg_thermal_cpu_online, pkg_thermal_cpu_offline);
+       if (ret < 0)
+               goto err;
+
+       /* Store the state for module exit */
+       pkg_thermal_hp_state = ret;
 
        platform_thermal_package_notify = pkg_thermal_notify;
        platform_thermal_package_rate_control = pkg_thermal_rate_control;
@@ -559,28 +535,18 @@ static int __init pkg_temp_thermal_init(void)
        pkg_temp_debugfs_init();
        return 0;
 
-err_ret:
-       for_each_online_cpu(i)
-               put_core_offline(i);
-       cpu_notifier_register_done();
+err:
        kfree(packages);
-       return -ENODEV;
+       return ret;
 }
 module_init(pkg_temp_thermal_init)
 
 static void __exit pkg_temp_thermal_exit(void)
 {
-       int i;
-
        platform_thermal_package_notify = NULL;
        platform_thermal_package_rate_control = NULL;
 
-       cpu_notifier_register_begin();
-       __unregister_hotcpu_notifier(&pkg_temp_thermal_notifier);
-       for_each_online_cpu(i)
-               put_core_offline(i);
-       cpu_notifier_register_done();
-
+       cpuhp_remove_state(pkg_thermal_hp_state);
        debugfs_remove_recursive(debugfs);
        kfree(packages);
 }