-static void _rcu_barrier(enum rcu_barrier type)
-{
- BUG_ON(in_interrupt());
- /* Take cpucontrol mutex to protect against CPU hotplug */
- mutex_lock(&rcu_barrier_mutex);
- init_completion(&rcu_barrier_completion);
- /*
- * Initialize rcu_barrier_cpu_count to 1, then invoke
- * rcu_barrier_func() on each CPU, so that each CPU also has
- * incremented rcu_barrier_cpu_count. Only then is it safe to
- * decrement rcu_barrier_cpu_count -- otherwise the first CPU
- * might complete its grace period before all of the other CPUs
- * did their increment, causing this function to return too
- * early.
- */
- atomic_set(&rcu_barrier_cpu_count, 1);
- on_each_cpu(rcu_barrier_func, (void *)type, 1);
- if (atomic_dec_and_test(&rcu_barrier_cpu_count))
- complete(&rcu_barrier_completion);
- wait_for_completion(&rcu_barrier_completion);
- mutex_unlock(&rcu_barrier_mutex);
- wait_migrated_callbacks();
-}
-
-/**
- * rcu_barrier - Wait until all in-flight call_rcu() callbacks complete.
- */
-void rcu_barrier(void)
-{
- _rcu_barrier(RCU_BARRIER_STD);
-}
-EXPORT_SYMBOL_GPL(rcu_barrier);
-
-/**
- * rcu_barrier_bh - Wait until all in-flight call_rcu_bh() callbacks complete.
- */
-void rcu_barrier_bh(void)
-{
- _rcu_barrier(RCU_BARRIER_BH);
-}
-EXPORT_SYMBOL_GPL(rcu_barrier_bh);
-
-/**
- * rcu_barrier_sched - Wait for in-flight call_rcu_sched() callbacks.
- */
-void rcu_barrier_sched(void)
-{
- _rcu_barrier(RCU_BARRIER_SCHED);
-}
-EXPORT_SYMBOL_GPL(rcu_barrier_sched);
-
-static void rcu_migrate_callback(struct rcu_head *notused)
-{
- if (atomic_dec_and_test(&rcu_migrate_type_count))
- wake_up(&rcu_migrate_wq);
-}
-
-extern int rcu_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu);
-
-static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self,
- unsigned long action, void *hcpu)
-{
- rcu_cpu_notify(self, action, hcpu);
- if (action == CPU_DYING) {
- /*
- * preempt_disable() in on_each_cpu() prevents stop_machine(),
- * so when "on_each_cpu(rcu_barrier_func, (void *)type, 1);"
- * returns, all online cpus have queued rcu_barrier_func(),
- * and the dead cpu(if it exist) queues rcu_migrate_callback()s.
- *
- * These callbacks ensure _rcu_barrier() waits for all
- * RCU callbacks of the specified type to complete.
- */
- atomic_set(&rcu_migrate_type_count, 3);
- call_rcu_bh(rcu_migrate_head, rcu_migrate_callback);
- call_rcu_sched(rcu_migrate_head + 1, rcu_migrate_callback);
- call_rcu(rcu_migrate_head + 2, rcu_migrate_callback);
- } else if (action == CPU_DOWN_PREPARE) {
- /* Don't need to wait until next removal operation. */
- /* rcu_migrate_head is protected by cpu_add_remove_lock */
- wait_migrated_callbacks();
- }
-
- return NOTIFY_OK;
-}
-
-void __init rcu_init(void)
-{
- int i;
-
- __rcu_init();
- cpu_notifier(rcu_barrier_cpu_hotplug, 0);
-
- /*
- * We don't need protection against CPU-hotplug here because
- * this is called early in boot, before either interrupts
- * or the scheduler are operational.
- */
- for_each_online_cpu(i)
- rcu_barrier_cpu_hotplug(NULL, CPU_UP_PREPARE, (void *)(long)i);
-}
-
-void rcu_scheduler_starting(void)