1 files changed, 23 insertions, 23 deletions

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 9eb7fed0bba..16d8ddd268b 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -52,8 +52,21 @@ enum KTHREAD_BITS {
 	KTHREAD_IS_PARKED,
 };
 
-#define to_kthread(tsk)	\
-	container_of((tsk)->vfork_done, struct kthread, exited)
+#define __to_kthread(vfork)	\
+	container_of(vfork, struct kthread, exited)
+
+static inline struct kthread *to_kthread(struct task_struct *k)
+{
+	return __to_kthread(k->vfork_done);
+}
+
+static struct kthread *to_live_kthread(struct task_struct *k)
+{
+	struct completion *vfork = ACCESS_ONCE(k->vfork_done);
+	if (likely(vfork))
+		return __to_kthread(vfork);
+	return NULL;
+}
 
 /**
  * kthread_should_stop - should this kthread return now?
@@ -265,7 +278,7 @@ static void __kthread_bind(struct task_struct *p, unsigned int cpu, long state)
 	}
 	/* It's safe because the task is inactive. */
 	do_set_cpus_allowed(p, cpumask_of(cpu));
-	p->flags |= PF_THREAD_BOUND;
+	p->flags |= PF_NO_SETAFFINITY;
 }
 
 /**
@@ -311,19 +324,6 @@ struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
 	return p;
 }
 
-static struct kthread *task_get_live_kthread(struct task_struct *k)
-{
-	struct kthread *kthread;
-
-	get_task_struct(k);
-	kthread = to_kthread(k);
-	/* It might have exited */
-	barrier();
-	if (k->vfork_done != NULL)
-		return kthread;
-	return NULL;
-}
-
 static void __kthread_unpark(struct task_struct *k, struct kthread *kthread)
 {
 	clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
@@ -350,11 +350,10 @@ static void __kthread_unpark(struct task_struct *k, struct kthread *kthread)
  */
 void kthread_unpark(struct task_struct *k)
 {
-	struct kthread *kthread = task_get_live_kthread(k);
+	struct kthread *kthread = to_live_kthread(k);
 
 	if (kthread)
 		__kthread_unpark(k, kthread);
-	put_task_struct(k);
 }
 
 /**
@@ -371,7 +370,7 @@ void kthread_unpark(struct task_struct *k)
  */
 int kthread_park(struct task_struct *k)
 {
-	struct kthread *kthread = task_get_live_kthread(k);
+	struct kthread *kthread = to_live_kthread(k);
 	int ret = -ENOSYS;
 
 	if (kthread) {
@@ -384,7 +383,6 @@ int kthread_park(struct task_struct *k)
 		}
 		ret = 0;
 	}
-	put_task_struct(k);
 	return ret;
 }
 
@@ -405,10 +403,13 @@ int kthread_park(struct task_struct *k)
  */
 int kthread_stop(struct task_struct *k)
 {
-	struct kthread *kthread = task_get_live_kthread(k);
+	struct kthread *kthread;
 	int ret;
 
 	trace_sched_kthread_stop(k);
+
+	get_task_struct(k);
+	kthread = to_live_kthread(k);
 	if (kthread) {
 		set_bit(KTHREAD_SHOULD_STOP, &kthread->flags);
 		__kthread_unpark(k, kthread);
@@ -416,10 +417,9 @@ int kthread_stop(struct task_struct *k)
 		wait_for_completion(&kthread->exited);
 	}
 	ret = k->exit_code;
-
 	put_task_struct(k);
-	trace_sched_kthread_stop_ret(ret);
 
+	trace_sched_kthread_stop_ret(ret);
 	return ret;
 }
 EXPORT_SYMBOL(kthread_stop);