diff options
Diffstat (limited to 'kernel/stop_machine.c')
| -rw-r--r-- | kernel/stop_machine.c | 26 |
1 files changed, 21 insertions, 5 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index 912823e2a11b..22d1d77f9a62 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -40,6 +40,8 @@ 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); +/* do not start up until all worklets have been placed: */ +static DEFINE_MUTEX(startup_lock); /* Users of stop_machine. */ static int refcount; static struct workqueue_struct *stop_machine_wq; @@ -71,6 +73,15 @@ static void stop_cpu(struct work_struct *unused) int cpu = smp_processor_id(); int err; + /* + * Wait for the startup loop to finish: + */ + mutex_lock(&startup_lock); + /* + * Let other threads continue too: + */ + mutex_unlock(&startup_lock); + if (!active_cpus) { if (cpu == cpumask_first(cpu_online_mask)) smdata = &active; @@ -166,16 +177,21 @@ int __stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus) set_state(STOPMACHINE_PREPARE); - /* Schedule the stop_cpu work on all cpus: hold this CPU so one - * doesn't hit this CPU until we're ready. */ - get_cpu(); + /* + * Schedule the stop_cpu work on all cpus before allowing any + * of the CPUs to execute it: + */ + mutex_lock(&startup_lock); + for_each_online_cpu(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(); + + /* This will release the thread on all CPUs: */ + mutex_unlock(&startup_lock); + flush_workqueue(stop_machine_wq); ret = active.fnret; mutex_unlock(&lock); |