rcu: Remove ->rgos_polled field from rcu_gp_oldstate structure

Because both normal and expedited grace periods increment their respective
counters on their pre-scheduler early boot fastpaths, the rcu_gp_oldstate
structure no longer needs its ->rgos_polled field.  This commit therefore
removes this field, shrinking this structure so that it is the same size
as an rcu_head structure.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

include/linux/rcutree.h

@@ -44,7 +44,6 @@ bool rcu_gp_might_be_stalled(void);
 struct rcu_gp_oldstate {
 	unsigned long rgos_norm;
 	unsigned long rgos_exp;
-	unsigned long rgos_polled;
 };
 
 unsigned long start_poll_synchronize_rcu_expedited(void);

kernel/rcu/tree.c

@@ -3526,7 +3526,6 @@ void get_completed_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
 {
 	rgosp->rgos_norm = RCU_GET_STATE_COMPLETED;
 	rgosp->rgos_exp = RCU_GET_STATE_COMPLETED;
-	rgosp->rgos_polled = RCU_GET_STATE_COMPLETED;
 }
 EXPORT_SYMBOL_GPL(get_completed_synchronize_rcu_full);
 
@@ -3575,7 +3574,6 @@ void get_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
 	smp_mb();  /* ^^^ */
 	rgosp->rgos_norm = rcu_seq_snap(&rnp->gp_seq);
 	rgosp->rgos_exp = rcu_seq_snap(&rcu_state.expedited_sequence);
-	rgosp->rgos_polled = rcu_seq_snap(&rcu_state.gp_seq_polled);
 }
 EXPORT_SYMBOL_GPL(get_state_synchronize_rcu_full);
 
@@ -3727,9 +3725,7 @@ bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
 	if (rgosp->rgos_norm == RCU_GET_STATE_COMPLETED ||
 	    rcu_seq_done_exact(&rnp->gp_seq, rgosp->rgos_norm) ||
 	    rgosp->rgos_exp == RCU_GET_STATE_COMPLETED ||
-	    rcu_seq_done_exact(&rcu_state.expedited_sequence, rgosp->rgos_exp) ||
-	    rgosp->rgos_polled == RCU_GET_STATE_COMPLETED ||
-	    rcu_seq_done_exact(&rcu_state.gp_seq_polled, rgosp->rgos_polled)) {
+	    rcu_seq_done_exact(&rcu_state.expedited_sequence, rgosp->rgos_exp)) {
 		smp_mb(); /* Ensure GP ends before subsequent accesses. */
 		return true;
 	}