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-rw-r--r--kernel/kthread.c26
1 files changed, 16 insertions, 10 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 9eb7fed0bba..a84dee265f9 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?
@@ -313,15 +326,8 @@ struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
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;
+ return to_live_kthread(k);
}
static void __kthread_unpark(struct task_struct *k, struct kthread *kthread)