rcu: Remove #ifdef CONFIG_SMP from TREE_RCU

Now that both TINY_RCU and TINY_PREEMPT_RCU have been in place for awhile,
it is time to remove UP support from TREE_RCU, which is what this commit
does.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

kernel/rcutree.c

@@ -301,8 +301,6 @@ static struct rcu_node *rcu_get_root(struct rcu_state *rsp)
 	return &rsp->node[0];
 }
 
-#ifdef CONFIG_SMP
-
 /*
  * If the specified CPU is offline, tell the caller that it is in
  * a quiescent state.  Otherwise, whack it with a reschedule IPI.
@@ -339,8 +337,6 @@ static int rcu_implicit_offline_qs(struct rcu_data *rdp)
 	return 0;
 }
 
-#endif /* #ifdef CONFIG_SMP */
-
 /*
  * rcu_idle_enter_common - inform RCU that current CPU is moving towards idle
  *
@@ -606,8 +602,6 @@ int rcu_is_cpu_rrupt_from_idle(void)
 	return __get_cpu_var(rcu_dynticks).dynticks_nesting <= 1;
 }
 
-#ifdef CONFIG_SMP
-
 /*
  * Snapshot the specified CPU's dynticks counter so that we can later
  * credit them with an implicit quiescent state.  Return 1 if this CPU
@@ -651,8 +645,6 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
 	return rcu_implicit_offline_qs(rdp);
 }
 
-#endif /* #ifdef CONFIG_SMP */
-
 static void record_gp_stall_check_time(struct rcu_state *rsp)
 {
 	rsp->gp_start = jiffies;
@@ -1517,8 +1509,6 @@ void rcu_check_callbacks(int cpu, int user)
 	trace_rcu_utilization("End scheduler-tick");
 }
 
-#ifdef CONFIG_SMP
-
 /*
  * Scan the leaf rcu_node structures, processing dyntick state for any that
  * have not yet encountered a quiescent state, using the function specified.
@@ -1641,15 +1631,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
 	trace_rcu_utilization("End fqs");
 }
 
-#else /* #ifdef CONFIG_SMP */
-
-static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
-{
-	set_need_resched();
-}
-
-#endif /* #else #ifdef CONFIG_SMP */
-
 /*
  * This does the RCU core processing work for the specified rcu_state
  * and rcu_data structures.  This may be called only from the CPU to

kernel/rcutree_plugin.h

@@ -1858,16 +1858,6 @@ static void __cpuinit rcu_prepare_kthreads(int cpu)
 
 #endif /* #else #ifdef CONFIG_RCU_BOOST */
 
-#ifndef CONFIG_SMP
-
-void synchronize_sched_expedited(void)
-{
-	cond_resched();
-}
-EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
-
-#else /* #ifndef CONFIG_SMP */
-
 static atomic_t sync_sched_expedited_started = ATOMIC_INIT(0);
 static atomic_t sync_sched_expedited_done = ATOMIC_INIT(0);
 
@@ -1982,8 +1972,6 @@ void synchronize_sched_expedited(void)
 }
 EXPORT_SYMBOL_GPL(synchronize_sched_expedited);
 
-#endif /* #else #ifndef CONFIG_SMP */
-
 #if !defined(CONFIG_RCU_FAST_NO_HZ)
 
 /*