[PATCH] Use kernel_power_off in sysrq-o

We already do all of the gymnastics to run from process context
to call the power off code so call into the power off code cleanly.

This especially helps acpi as part of it's shutdown logic should
run acpi_shutdown called from device_shutdown which was not
being called from here.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/power/poweroff.c

@@ -9,6 +9,7 @@
 #include <linux/init.h>
 #include <linux/pm.h>
 #include <linux/workqueue.h>
+#include <linux/reboot.h>
 
 /*
  * When the user hits Sys-Rq o to power down the machine this is the
@@ -17,8 +18,7 @@
 
 static void do_poweroff(void *dummy)
 {
-	if (pm_power_off)
-		pm_power_off();
+	kernel_power_off();
 }
 
 static DECLARE_WORK(poweroff_work, do_poweroff, NULL);