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-rw-r--r--kernel/cpu.c37
1 files changed, 19 insertions, 18 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index b03a32595cfe..ab860453841d 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -271,11 +271,25 @@ void cpu_hotplug_enable(void)
EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
#endif /* CONFIG_HOTPLUG_CPU */
+static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st);
+
static int bringup_wait_for_ap(unsigned int cpu)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+ /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */
wait_for_completion(&st->done);
+ BUG_ON(!cpu_online(cpu));
+
+ /* Unpark the stopper thread and the hotplug thread of the target cpu */
+ stop_machine_unpark(cpu);
+ kthread_unpark(st->thread);
+
+ /* Should we go further up ? */
+ if (st->target > CPUHP_AP_ONLINE_IDLE) {
+ __cpuhp_kick_ap_work(st);
+ wait_for_completion(&st->done);
+ }
return st->result;
}
@@ -296,9 +310,7 @@ static int bringup_cpu(unsigned int cpu)
irq_unlock_sparse();
if (ret)
return ret;
- ret = bringup_wait_for_ap(cpu);
- BUG_ON(!cpu_online(cpu));
- return ret;
+ return bringup_wait_for_ap(cpu);
}
/*
@@ -767,31 +779,20 @@ void notify_cpu_starting(unsigned int cpu)
}
/*
- * Called from the idle task. We need to set active here, so we can kick off
- * the stopper thread and unpark the smpboot threads. If the target state is
- * beyond CPUHP_AP_ONLINE_IDLE we kick cpuhp thread and let it bring up the
- * cpu further.
+ * Called from the idle task. Wake up the controlling task which brings the
+ * stopper and the hotplug thread of the upcoming CPU up and then delegates
+ * the rest of the online bringup to the hotplug thread.
*/
void cpuhp_online_idle(enum cpuhp_state state)
{
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
- unsigned int cpu = smp_processor_id();
/* Happens for the boot cpu */
if (state != CPUHP_AP_ONLINE_IDLE)
return;
st->state = CPUHP_AP_ONLINE_IDLE;
-
- /* Unpark the stopper thread and the hotplug thread of this cpu */
- stop_machine_unpark(cpu);
- kthread_unpark(st->thread);
-
- /* Should we go further up ? */
- if (st->target > CPUHP_AP_ONLINE_IDLE)
- __cpuhp_kick_ap_work(st);
- else
- complete(&st->done);
+ complete(&st->done);
}
/* Requires cpu_add_remove_lock to be held */