+ struct callback_head *work, *head, *next;
+
+ for (;;) {
+ /*
+ * work->func() can do task_work_add(), do not set
+ * work_exited unless the list is empty.
+ */
+ do {
+ work = ACCESS_ONCE(task->task_works);
+ head = !work && (task->flags & PF_EXITING) ?
+ &work_exited : NULL;
+ } while (cmpxchg(&task->task_works, work, head) != work);