rcu: Remove obsolete __rcu_pending() statistics for debugfs

The debugfs interface displayed statistics on RCU-pending checks
but this interface has since been removed.  This commit therefore
removes the no-longer-used rcu_data structure's ->n_rcu_pending,
->n_rp_core_needs_qs, ->n_rp_report_qs, ->n_rp_cb_ready,
->n_rp_cpu_needs_gp, ->n_rp_gp_completed, ->n_rp_gp_started,
->n_rp_nocb_defer_wakeup, and ->n_rp_need_nothing fields along with
their updates.

If this information proves necessary in the future, the corresponding
event traces will be added.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8e07119..99d59be 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3354,8 +3354,6 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
 {
 	struct rcu_node *rnp = rdp->mynode;
 
-	rdp->n_rcu_pending++;
-
 	/* Check for CPU stalls, if enabled. */
 	check_cpu_stall(rsp, rdp);
 
@@ -3364,48 +3362,31 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
 		return 0;
 
 	/* Is the RCU core waiting for a quiescent state from this CPU? */
-	if (rcu_scheduler_fully_active &&
-	    rdp->core_needs_qs && rdp->cpu_no_qs.b.norm &&
-	    rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_dynticks.rcu_qs_ctr)) {
-		rdp->n_rp_core_needs_qs++;
-	} else if (rdp->core_needs_qs && !rdp->cpu_no_qs.b.norm) {
-		rdp->n_rp_report_qs++;
+	if (rdp->core_needs_qs && !rdp->cpu_no_qs.b.norm)
 		return 1;
-	}
 
 	/* Does this CPU have callbacks ready to invoke? */
-	if (rcu_segcblist_ready_cbs(&rdp->cblist)) {
-		rdp->n_rp_cb_ready++;
+	if (rcu_segcblist_ready_cbs(&rdp->cblist))
 		return 1;
-	}
 
 	/* Has RCU gone idle with this CPU needing another grace period? */
-	if (cpu_needs_another_gp(rsp, rdp)) {
-		rdp->n_rp_cpu_needs_gp++;
+	if (cpu_needs_another_gp(rsp, rdp))
 		return 1;
-	}
 
 	/* Has another RCU grace period completed?  */
-	if (READ_ONCE(rnp->completed) != rdp->completed) { /* outside lock */
-		rdp->n_rp_gp_completed++;
+	if (READ_ONCE(rnp->completed) != rdp->completed) /* outside lock */
 		return 1;
-	}
 
 	/* Has a new RCU grace period started? */
 	if (READ_ONCE(rnp->gpnum) != rdp->gpnum ||
-	    unlikely(READ_ONCE(rdp->gpwrap))) { /* outside lock */
-		rdp->n_rp_gp_started++;
+	    unlikely(READ_ONCE(rdp->gpwrap))) /* outside lock */
 		return 1;
-	}
 
 	/* Does this CPU need a deferred NOCB wakeup? */
-	if (rcu_nocb_need_deferred_wakeup(rdp)) {
-		rdp->n_rp_nocb_defer_wakeup++;
+	if (rcu_nocb_need_deferred_wakeup(rdp))
 		return 1;
-	}
 
 	/* nothing to do */
-	rdp->n_rp_need_nothing++;
 	return 0;
 }