__init_waitqueue_head
__init_waitqueue_head(&fence->wait, name, key);
__init_waitqueue_head(&fence->wait, name, key);
extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *);
__init_waitqueue_head((wq_head), #wq_head, &__key); \
EXPORT_SYMBOL(__init_waitqueue_head);