rcu: Convert ->completedqs to ->gp_seq

This commit switches the quiescent-state no-backtracking checks from
->gpnum and ->completed to ->gp_seq.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

kernel/rcu/tree.c

@@ -2278,7 +2278,7 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp,
 			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
 			return;
 		}
-		rnp->completedqs = rnp->gpnum;
+		rnp->completedqs = rnp->gp_seq;
 		mask = rnp->grpmask;
 		if (rnp->parent == NULL) {
 
@@ -3951,7 +3951,7 @@ static void __init rcu_init_one(struct rcu_state *rsp)
 			rnp->gpnum = rsp->gpnum;
 			rnp->completed = rsp->completed;
 			rnp->gp_seq = rsp->gp_seq;
-			rnp->completedqs = rsp->completed;
+			rnp->completedqs = rsp->gp_seq;
 			rnp->qsmask = 0;
 			rnp->qsmaskinit = 0;
 			rnp->grplo = j * cpustride;

kernel/rcu/tree_plugin.h

@@ -262,7 +262,7 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
 	 */
 	if (!rnp->gp_tasks && (blkd_state & RCU_GP_BLKD)) {
 		rnp->gp_tasks = &t->rcu_node_entry;
-		WARN_ON_ONCE(rnp->completedqs == rnp->gpnum);
+		WARN_ON_ONCE(rnp->completedqs == rnp->gp_seq);
 	}
 	if (!rnp->exp_tasks && (blkd_state & RCU_EXP_BLKD))
 		rnp->exp_tasks = &t->rcu_node_entry;
@@ -537,7 +537,7 @@ void rcu_read_unlock_special(struct task_struct *t)
 		WARN_ON_ONCE(rnp != t->rcu_blocked_node);
 		WARN_ON_ONCE(!rcu_is_leaf_node(rnp));
 		empty_norm = !rcu_preempt_blocked_readers_cgp(rnp);
-		WARN_ON_ONCE(rnp->completedqs == rnp->gpnum &&
+		WARN_ON_ONCE(rnp->completedqs == rnp->gp_seq &&
 			     (!empty_norm || rnp->qsmask));
 		empty_exp = sync_rcu_preempt_exp_done(rnp);
 		smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */