rht_for_each_rcu
rht_for_each_rcu(he, tbl, b) {
rht_for_each_rcu(he, tbl, b)
rht_for_each_rcu(p, iter->walker.tbl, iter->slot) {
rht_for_each_rcu(p, iter->walker.tbl, iter->slot) {
rht_for_each_rcu(p, tbl, iter->slot) {