static unsigned int num_threads;
static atomic_t thread_ack;
static DEFINE_MUTEX(lock);
-
+/* setup_lock protects refcount, stop_machine_wq and stop_machine_work. */
+static DEFINE_MUTEX(setup_lock);
+/* Users of stop_machine. */
+static int refcount;
static struct workqueue_struct *stop_machine_wq;
static struct stop_machine_data active, idle;
-static const cpumask_t *active_cpus;
-static void *stop_machine_work;
+static const struct cpumask *active_cpus;
+static void __percpu *stop_machine_work;
static void set_state(enum stopmachine_state newstate)
{
return 0;
}
+int stop_machine_create(void)
+{
+ mutex_lock(&setup_lock);
+ if (refcount)
+ goto done;
+ stop_machine_wq = create_rt_workqueue("kstop");
+ if (!stop_machine_wq)
+ goto err_out;
+ stop_machine_work = alloc_percpu(struct work_struct);
+ if (!stop_machine_work)
+ goto err_out;
+done:
+ refcount++;
+ mutex_unlock(&setup_lock);
+ return 0;
+
+err_out:
+ if (stop_machine_wq)
+ destroy_workqueue(stop_machine_wq);
+ mutex_unlock(&setup_lock);
+ return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(stop_machine_create);
+
+void stop_machine_destroy(void)
+{
+ mutex_lock(&setup_lock);
+ refcount--;
+ if (refcount)
+ goto done;
+ destroy_workqueue(stop_machine_wq);
+ free_percpu(stop_machine_work);
+done:
+ mutex_unlock(&setup_lock);
+}
+EXPORT_SYMBOL_GPL(stop_machine_destroy);
+
int __stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus)
{
struct work_struct *sm_work;
* doesn't hit this CPU until we're ready. */
get_cpu();
for_each_online_cpu(i) {
- sm_work = percpu_ptr(stop_machine_work, i);
+ sm_work = per_cpu_ptr(stop_machine_work, i);
INIT_WORK(sm_work, stop_cpu);
queue_work_on(i, stop_machine_wq, sm_work);
}
{
int ret;
+ ret = stop_machine_create();
+ if (ret)
+ return ret;
/* No CPUs can come up or down during this. */
get_online_cpus();
ret = __stop_machine(fn, data, cpus);
put_online_cpus();
-
+ stop_machine_destroy();
return ret;
}
EXPORT_SYMBOL_GPL(stop_machine);
-
-static int __init stop_machine_init(void)
-{
- stop_machine_wq = create_rt_workqueue("kstop");
- stop_machine_work = alloc_percpu(struct work_struct);
- return 0;
-}
-core_initcall(stop_machine_init);