rcu: Add leaf-node macros

This commit adds rcu_first_leaf_node() that returns a pointer to
the first leaf rcu_node structure in the specified RCU flavor and an
rcu_is_leaf_node() that returns true iff the specified rcu_node structure
is a leaf.  This commit also uses these macros where appropriate.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Nicholas Piggin <npiggin@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index c4db0e20b035..b22d2e1ca5c0 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2398,7 +2398,7 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp,
                         return;
                 }
                 WARN_ON_ONCE(oldmask); /* Any child must be all zeroed! */
-                WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1 &&
+                WARN_ON_ONCE(!rcu_is_leaf_node(rnp) &&
                              rcu_preempt_blocked_readers_cgp(rnp));
                 rnp->qsmask &= ~mask;
                 trace_rcu_quiescent_state_report(rsp->name, rnp->gpnum,
@@ -4056,7 +4056,7 @@ static void __init rcu_init_one(struct rcu_state *rsp)
 
         init_swait_queue_head(&rsp->gp_wq);
         init_swait_queue_head(&rsp->expedited_wq);
-        rnp = rsp->level[rcu_num_lvls - 1];
+        rnp = rcu_first_leaf_node(rsp);
         for_each_possible_cpu(i) {
                 while (i > rnp->grphi)
                         rnp++;