add_wait_queue_priority
add_wait_queue_priority(wqh, &irqfd->irqfd_wait);
add_wait_queue_priority(wqh, &kirqfd->wait);
extern void add_wait_queue_priority(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
EXPORT_SYMBOL_GPL(add_wait_queue_priority);