1 files changed, 49 insertions, 14 deletions

diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 24e8ceacc388..0cd415ee62a2 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -38,7 +38,10 @@ 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;
@@ -69,10 +72,10 @@ static void stop_cpu(struct work_struct *unused)
         int err;
 
         if (!active_cpus) {
-                if (cpu == first_cpu(cpu_online_map))
+                if (cpu == cpumask_first(cpu_online_mask))
                         smdata = &active;
         } else {
-                if (cpu_isset(cpu, *active_cpus))
+                if (cpumask_test_cpu(cpu, active_cpus))
                         smdata = &active;
         }
         /* Simple state machine */
@@ -109,7 +112,44 @@ static int chill(void *unused)
         return 0;
 }
 
-int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
+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;
         int i, ret;
@@ -142,23 +182,18 @@ int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
         return ret;
 }
 
-int stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
+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);