rcu: Move rcu_request_urgent_qs_task() out of rcutiny.h and rcutree.h

The rcu_request_urgent_qs_task() function is used only within RCU,
so there is no point in exporting it to the rest of the kernel from
nclude/linux/rcutiny.h and include/linux/rcutree.h.  This commit therefore
moves this function to kernel/rcu/rcu.h.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

include/linux/rcutiny.h

@@ -157,10 +157,6 @@ static inline bool rcu_is_watching(void)
 	return true;
 }
 
-static inline void rcu_request_urgent_qs_task(struct task_struct *t)
-{
-}
-
 static inline void rcu_all_qs(void)
 {
 	barrier(); /* Avoid RCU read-side critical sections leaking across. */

include/linux/rcutree.h

@@ -91,10 +91,7 @@ void exit_rcu(void);
 
 void rcu_scheduler_starting(void);
 extern int rcu_scheduler_active __read_mostly;
-
 bool rcu_is_watching(void);
-void rcu_request_urgent_qs_task(struct task_struct *t);
-
 void rcu_all_qs(void);
 
 /* RCUtree hotplug events */

kernel/rcu/rcu.h

@@ -335,6 +335,12 @@ void rcupdate_announce_bootup_oddness(void);
 #define RCU_SCHEDULER_INIT	1
 #define RCU_SCHEDULER_RUNNING	2
 
+#ifdef CONFIG_TINY_RCU
+static inline void rcu_request_urgent_qs_task(struct task_struct *t) { }
+#else /* #ifdef CONFIG_TINY_RCU */
+void rcu_request_urgent_qs_task(struct task_struct *t);
+#endif /* #else #ifdef CONFIG_TINY_RCU */
+
 enum rcutorture_type {
 	RCU_FLAVOR,
 	RCU_BH_FLAVOR,