rcu_advance_cbs
WARN_ON_ONCE(rcu_advance_cbs(rnp, rdp));
ret = rcu_advance_cbs(rnp, rdp); /* Advance CBs. */
needwake = rcu_advance_cbs(my_rnp, rdp) ||
rcu_advance_cbs(my_rnp, my_rdp);
needwake = needwake || rcu_advance_cbs(my_rnp, my_rdp);
needwake_gp = rcu_advance_cbs(rnp, rdp);
needwake_gp = rcu_advance_cbs(rdp->mynode, rdp);