X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fstop_machine.c;h=912823e2a11b0afb0f4448e5163bb9e39c7fc8b8;hb=5dab600e6a153ceb64832f608069e6c08185411a;hp=286c41722e8cb68e76dc637d20298b67847771e0;hpb=41c7bb9588904eb060a95bcad47bd3804a1ece25;p=safe%2Fjmp%2Flinux-2.6

diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 286c417..912823e 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -38,10 +38,13 @@ struct stop_machine_data {
 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 const struct cpumask *active_cpus;
 static void *stop_machine_work;
 
 static void set_state(enum stopmachine_state newstate)
@@ -109,6 +112,43 @@ static int chill(void *unused)
 	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;
@@ -130,7 +170,7 @@ int __stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus)
 	 * 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);
 	}
@@ -146,19 +186,14 @@ int stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus)
 {
 	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);