x86/hpet: Convert to hotplug state machine

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

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153335.279718463@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index f112af7aa62edb1b6167e1801040af07288fb2ac..3d747070fe6702a1c3bdf764c8de3bfb3f202038 100644 (file)
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -710,31 +710,29 @@ static void hpet_work(struct work_struct *w)
        complete(&hpet_work->complete);
 }
 
-static int hpet_cpuhp_notify(struct notifier_block *n,
-               unsigned long action, void *hcpu)
+static int hpet_cpuhp_online(unsigned int cpu)
 {
-       unsigned long cpu = (unsigned long)hcpu;
        struct hpet_work_struct work;
+
+       INIT_DELAYED_WORK_ONSTACK(&work.work, hpet_work);
+       init_completion(&work.complete);
+       /* FIXME: add schedule_work_on() */
+       schedule_delayed_work_on(cpu, &work.work, 0);
+       wait_for_completion(&work.complete);
+       destroy_delayed_work_on_stack(&work.work);
+       return 0;
+}
+
+static int hpet_cpuhp_dead(unsigned int cpu)
+{
        struct hpet_dev *hdev = per_cpu(cpu_hpet_dev, cpu);
 
-       switch (action & ~CPU_TASKS_FROZEN) {
-       case CPU_ONLINE:
-               INIT_DELAYED_WORK_ONSTACK(&work.work, hpet_work);
-               init_completion(&work.complete);
-               /* FIXME: add schedule_work_on() */
-               schedule_delayed_work_on(cpu, &work.work, 0);
-               wait_for_completion(&work.complete);
-               destroy_delayed_work_on_stack(&work.work);
-               break;
-       case CPU_DEAD:
-               if (hdev) {
-                       free_irq(hdev->irq, hdev);
-                       hdev->flags &= ~HPET_DEV_USED;
-                       per_cpu(cpu_hpet_dev, cpu) = NULL;
-               }
-               break;
-       }
-       return NOTIFY_OK;
+       if (!hdev)
+               return 0;
+       free_irq(hdev->irq, hdev);
+       hdev->flags &= ~HPET_DEV_USED;
+       per_cpu(cpu_hpet_dev, cpu) = NULL;
+       return 0;
 }
 #else
 
@@ -750,11 +748,8 @@ static void hpet_reserve_msi_timers(struct hpet_data *hd)
 }
 #endif
 
-static int hpet_cpuhp_notify(struct notifier_block *n,
-               unsigned long action, void *hcpu)
-{
-       return NOTIFY_OK;
-}
+#define hpet_cpuhp_online      NULL
+#define hpet_cpuhp_dead                NULL
 
 #endif
 
@@ -931,7 +926,7 @@ out_nohpet:
  */
 static __init int hpet_late_init(void)
 {
-       int cpu;
+       int ret;
 
        if (boot_hpet_disable)
                return -ENODEV;
@@ -961,16 +956,20 @@ static __init int hpet_late_init(void)
        if (boot_cpu_has(X86_FEATURE_ARAT))
                return 0;
 
-       cpu_notifier_register_begin();
-       for_each_online_cpu(cpu) {
-               hpet_cpuhp_notify(NULL, CPU_ONLINE, (void *)(long)cpu);
-       }
-
        /* This notifier should be called after workqueue is ready */
-       __hotcpu_notifier(hpet_cpuhp_notify, -20);
-       cpu_notifier_register_done();
-
+       ret = cpuhp_setup_state(CPUHP_AP_X86_HPET_ONLINE, "AP_X86_HPET_ONLINE",
+                               hpet_cpuhp_online, NULL);
+       if (ret)
+               return ret;
+       ret = cpuhp_setup_state(CPUHP_X86_HPET_DEAD, "X86_HPET_DEAD", NULL,
+                               hpet_cpuhp_dead);
+       if (ret)
+               goto err_cpuhp;
        return 0;
+
+err_cpuhp:
+       cpuhp_remove_state(CPUHP_AP_X86_HPET_ONLINE);
+       return ret;
 }
 fs_initcall(hpet_late_init);
 

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 60557a9e783d5145f5dcaaa8b376c7f0590cb2ed..7449081ff4122c04727f3a4c137794af8e025ff6 100644 (file)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -12,6 +12,7 @@ enum cpuhp_state {
        CPUHP_PERF_BFIN,
        CPUHP_PERF_POWER,
        CPUHP_PERF_SUPERH,
+       CPUHP_X86_HPET_DEAD,
        CPUHP_WORKQUEUE_PREP,
        CPUHP_NOTIFY_PREPARE,
        CPUHP_BRINGUP_CPU,
@@ -54,6 +55,7 @@ enum cpuhp_state {
        CPUHP_AP_NOTIFY_ONLINE,
        CPUHP_AP_ONLINE_DYN,
        CPUHP_AP_ONLINE_DYN_END         = CPUHP_AP_ONLINE_DYN + 30,
+       CPUHP_AP_X86_HPET_ONLINE,
        CPUHP_AP_ACTIVE,
        CPUHP_ONLINE,
 };