wake_q_node
struct wake_q_node wake_q;
struct wake_q_node *next;
struct wake_q_node *first;
struct wake_q_node **lastp;
#define WAKE_Q_TAIL ((struct wake_q_node *) 0x01)
struct wake_q_node *node = &task->wake_q;
struct wake_q_node *node = head->first;