[PATCH] RCU - cpu-offline-cleanup

There is a series of patches in my tree and these 3 are the first ones that
should probably be merged down the road.  Descriptions are on top of the
patches.  Please include them in -mm.

A lot of RCU code will be cleaned up later in order to support
call_rcu_bh(), the separate RCU interface that considers softirq handler
completion a quiescent state.

This patch:

Minor cleanup of the hotplug code to remove #ifdef in cpu event notifier
handler.  If CONFIG_HOTPLUG_CPU is not defined, CPU_DEAD case will be
optimized off.
Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/rcupdate.c

@@ -243,6 +243,12 @@ static void rcu_offline_cpu(int cpu)
 	tasklet_kill_immediate(&RCU_tasklet(cpu), cpu);
 }
 
+#else
+
+static void rcu_offline_cpu(int cpu)
+{
+}
+
 #endif
 
 void rcu_restart_cpu(int cpu)
@@ -326,11 +332,9 @@ static int __devinit rcu_cpu_notify(struct notifier_block *self,
 	case CPU_UP_PREPARE:
 		rcu_online_cpu(cpu);
 		break;
-#ifdef CONFIG_HOTPLUG_CPU
 	case CPU_DEAD:
 		rcu_offline_cpu(cpu);
 		break;
-#endif
 	default:
 		break;
 	}