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Subject[patch V2 29/67] x86/hpet: Convert to hotplug state machine
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

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>
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>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
arch/x86/kernel/hpet.c | 69 +++++++++++++++++++++++-----------------------
include/linux/cpuhotplug.h | 2 ++
2 files changed, 36 insertions(+), 35 deletions(-)

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index f112af7..3d74707 100644
--- 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 60557a9..7449081 100644
--- 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,
};
--
2.8.1


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