[PATCH] cpu hotplug: add hotplug versions of cpu_notifier

Define new macros register_hotcpu_notifier() and unregister_hotcpu_notifier()
that redefines register_cpu_notifier() and unregister_cpu_notifier() for use
only when HOTPLUG_CPU is defined.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/cpu.h

@@ -79,13 +79,17 @@ extern int lock_cpu_hotplug_interruptible(void);
 		{ .notifier_call = fn, .priority = pri };	\
 	register_cpu_notifier(&fn##_nb);			\
 }
+#define register_hotcpu_notifier(nb)	register_cpu_notifier(nb)
+#define unregister_hotcpu_notifier(nb)	unregister_cpu_notifier(nb)
 int cpu_down(unsigned int cpu);
 #define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
 #else
 #define lock_cpu_hotplug()	do { } while (0)
 #define unlock_cpu_hotplug()	do { } while (0)
 #define lock_cpu_hotplug_interruptible() 0
 #define hotcpu_notifier(fn, pri)
+#define register_hotcpu_notifier(nb)
+#define unregister_hotcpu_notifier(nb)
 
 /* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */
 static inline int cpu_is_offline(int cpu) { return 0; }