rcu-tasks: Add printk()s to localize boot-time self-test hang

Currently, rcu_tasks_initiate_self_tests() prints a message and then
initiates self tests on up to three different RCU Tasks flavors.  If one
of the flavors has a grace-period hang, it is not easy to work out which
of the three hung.  This commit therefore prints a message prior to each
individual test.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>

Author: paulmckrcu

kernel/rcu/tasks.h

@@ -1979,20 +1979,22 @@ static void test_rcu_tasks_callback(struct rcu_head *rhp)
 
 static void rcu_tasks_initiate_self_tests(void)
 {
-	pr_info("Running RCU-tasks wait API self tests\n");
 #ifdef CONFIG_TASKS_RCU
+	pr_info("Running RCU Tasks wait API self tests\n");
 	tests[0].runstart = jiffies;
 	synchronize_rcu_tasks();
 	call_rcu_tasks(&tests[0].rh, test_rcu_tasks_callback);
 #endif
 
 #ifdef CONFIG_TASKS_RUDE_RCU
+	pr_info("Running RCU Tasks Rude wait API self tests\n");
 	tests[1].runstart = jiffies;
 	synchronize_rcu_tasks_rude();
 	call_rcu_tasks_rude(&tests[1].rh, test_rcu_tasks_callback);
 #endif
 
 #ifdef CONFIG_TASKS_TRACE_RCU
+	pr_info("Running RCU Tasks Trace wait API self tests\n");
 	tests[2].runstart = jiffies;
 	synchronize_rcu_tasks_trace();
 	call_rcu_tasks_trace(&tests[2].rh, test_rcu_tasks_callback);