rb_next_postorder
pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
extern struct rb_node *rb_next_postorder(const struct rb_node *);
pos && ({ n = rb_next_postorder(pos); 1; }); \
EXPORT_SYMBOL(rb_next_postorder);
for (rb = rb_first_postorder(&root.rb_root); rb; rb = rb_next_postorder(rb))
extern struct rb_node *rb_next_postorder(const struct rb_node *);
pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \