[PATCH] swsusp: disable nonboot CPUs before entering platform suspend

Prevent the WARN_ON() in arch/x86_64/kernel/acpi/sleep.c:init_low_mapping()
from triggering by disabling nonboot CPUs before we finally enter the
platform suspend.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/power/disk.c

@@ -58,6 +58,7 @@ static inline int platform_prepare(void)
 
 static void power_down(suspend_disk_method_t mode)
 {
+	disable_nonboot_cpus();
 	switch(mode) {
 	case PM_DISK_PLATFORM:
 		if (pm_ops && pm_ops->enter) {

kernel/power/user.c

@@ -398,9 +398,10 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
 
 		case PMOPS_ENTER:
 			if (data->platform_suspend) {
+				disable_nonboot_cpus();
 				kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
 				error = pm_ops->enter(PM_SUSPEND_DISK);
-				error = 0;
+				enable_nonboot_cpus();
 			}
 			break;