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)
{
enum stopmachine_state curstate = STOPMACHINE_NONE;
struct stop_machine_data *smdata = &idle;
int cpu = smp_processor_id();
+ 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 */
hard_irq_disable();
break;
case STOPMACHINE_RUN:
- /* |= allows error detection if functions on
- * multiple CPUs. */
- smdata->fnret |= smdata->fn(smdata->data);
+ /* On multiple CPUs only a single error code
+ * is needed to tell that something failed. */
+ err = smdata->fn(smdata->data);
+ if (err)
+ smdata->fnret = err;
break;
default:
break;
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;
+ int i, ret;
/* Set up initial state. */
mutex_lock(&lock);
* 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);
}
/* This will release the thread on our CPU. */
put_cpu();
flush_workqueue(stop_machine_wq);
+ ret = active.fnret;
mutex_unlock(&lock);
- return active.fnret;
+ 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;
-}
-early_initcall(stop_machine_init);