This commit adds trivial test code for srcu_down_read() and
srcu_up_read().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/update.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index a5b4abbee6439..a72f98c120f09 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -555,9 +555,12 @@ struct early_boot_kfree_rcu {
 static void early_boot_test_call_rcu(void)
 {
 	static struct rcu_head head;
+	int idx;
 	static struct rcu_head shead;
 	struct early_boot_kfree_rcu *rhp;
 
+	idx = srcu_down_read(&early_srcu);
+	srcu_up_read(&early_srcu, idx);
 	call_rcu(&head, test_callback);
 	early_srcu_cookie = start_poll_synchronize_srcu(&early_srcu);
 	call_srcu(&early_srcu, &shead, test_callback);
-- 
2.31.1.189.g2e36527f23