klist_add_head
extern void klist_add_head(struct klist_node *n, struct klist *k);
EXPORT_SYMBOL_GPL(klist_add_head);
klist_add_head(&a, &mylist);
klist_add_head(&b, &mylist);
klist_add_head(&a, &mylist);
klist_add_head(&b, &mylist);
klist_add_head(&a, &mylist);
klist_add_head(&b, &mylist);
klist_add_head(&a, &mylist);