x86/apb_timer: Convert to hotplug state machine

Install the callbacks via the state machine. There is no setup just one
teardown callback. Remove the silly comment about the workqueue up dependency.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153335.625342983@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/apb_timer.c b/arch/x86/kernel/apb_timer.c
index cefacbad153118620348bb1e3bc88838f75dcde7..456316f6c868dc1aff24585bdc9b0119e4804693 100644 (file)
--- a/arch/x86/kernel/apb_timer.c
+++ b/arch/x86/kernel/apb_timer.c
@@ -215,26 +215,18 @@ void apbt_setup_secondary_clock(void)
  * cpu timers during the offline process due to the ordering of notification.
  * the extra interrupt is harmless.
  */
-static int apbt_cpuhp_notify(struct notifier_block *n,
-                            unsigned long action, void *hcpu)
+static int apbt_cpu_dead(unsigned int cpu)
 {
-       unsigned long cpu = (unsigned long)hcpu;
        struct apbt_dev *adev = &per_cpu(cpu_apbt_dev, cpu);
 
-       switch (action & ~CPU_TASKS_FROZEN) {
-       case CPU_DEAD:
-               dw_apb_clockevent_pause(adev->timer);
-               if (system_state == SYSTEM_RUNNING) {
-                       pr_debug("skipping APBT CPU %lu offline\n", cpu);
-               } else {
-                       pr_debug("APBT clockevent for cpu %lu offline\n", cpu);
-                       dw_apb_clockevent_stop(adev->timer);
-               }
-               break;
-       default:
-               pr_debug("APBT notified %lu, no action\n", action);
+       dw_apb_clockevent_pause(adev->timer);
+       if (system_state == SYSTEM_RUNNING) {
+               pr_debug("skipping APBT CPU %u offline\n", cpu);
+       } else {
+               pr_debug("APBT clockevent for cpu %u offline\n", cpu);
+               dw_apb_clockevent_stop(adev->timer);
        }
-       return NOTIFY_OK;
+       return 0;
 }
 
 static __init int apbt_late_init(void)
@@ -242,9 +234,8 @@ static __init int apbt_late_init(void)
        if (intel_mid_timer_options == INTEL_MID_TIMER_LAPIC_APBT ||
                !apb_timer_block_enabled)
                return 0;
-       /* This notifier should be called after workqueue is ready */
-       hotcpu_notifier(apbt_cpuhp_notify, -20);
-       return 0;
+       return cpuhp_setup_state(CPUHP_X86_APB_DEAD, "X86_APB_DEAD", NULL,
+                                apbt_cpu_dead);
 }
 fs_initcall(apbt_late_init);
 #else

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 8c190a85af6e176a88e08174b69e01da72b52298..3e719ba44fbe8272481861f8e91fd589de6af1a0 100644 (file)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -13,6 +13,7 @@ enum cpuhp_state {
        CPUHP_PERF_POWER,
        CPUHP_PERF_SUPERH,
        CPUHP_X86_HPET_DEAD,
+       CPUHP_X86_APB_DEAD,
        CPUHP_WORKQUEUE_PREP,
        CPUHP_NOTIFY_PREPARE,
        CPUHP_BRINGUP_CPU,