PM: Convert PM notifiers to out-of-line code

This patch (as1008b) converts the PM notifier routines from inline
calls to out-of-line code.  It also prevents pm_chain_head from
being created when CONFIG_PM_SLEEP isn't enabled, and EXPORTs the
notifier registration and unregistration routines.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/kernel/power/main.c b/kernel/power/main.c
index fc717b8..0a9f269 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -24,13 +24,37 @@
 
 #include "power.h"
 
-BLOCKING_NOTIFIER_HEAD(pm_chain_head);
-
 DEFINE_MUTEX(pm_mutex);
 
 unsigned int pm_flags;
 EXPORT_SYMBOL(pm_flags);
 
+#ifdef CONFIG_PM_SLEEP
+
+/* Routines for PM-transition notifications */
+
+static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
+
+int register_pm_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&pm_chain_head, nb);
+}
+EXPORT_SYMBOL_GPL(register_pm_notifier);
+
+int unregister_pm_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&pm_chain_head, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_pm_notifier);
+
+int pm_notifier_call_chain(unsigned long val)
+{
+	return (blocking_notifier_call_chain(&pm_chain_head, val, NULL)
+			== NOTIFY_BAD) ? -EINVAL : 0;
+}
+
+#endif /* CONFIG_PM_SLEEP */
+
 #ifdef CONFIG_PM_DEBUG
 int pm_test_level = TEST_NONE;