[PATCH] Disable CPU hotplug during suspend
The current suspend code has to be run on one CPU, so we use the CPU
hotplug to take the non-boot CPUs offline on SMP machines. However, we
should also make sure that these CPUs will not be enabled by someone else
after we have disabled them.
The functions disable_nonboot_cpus() and enable_nonboot_cpus() are moved to
kernel/cpu.c, because they now refer to some stuff in there that should
better be static. Also it's better if disable_nonboot_cpus() returns an
error instead of panicking if something goes wrong, and
enable_nonboot_cpus() has no reason to panic(), because the CPUs may have
been enabled by the userland before it tries to take them online.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index e13e740..7c7b9b6 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -18,6 +18,7 @@
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pm.h>
+#include <linux/cpu.h>
#include "power.h"
@@ -72,7 +73,10 @@
int error;
pm_prepare_console();
- disable_nonboot_cpus();
+
+ error = disable_nonboot_cpus();
+ if (error)
+ goto enable_cpus;
if (freeze_processes()) {
error = -EBUSY;
@@ -84,6 +88,7 @@
return 0;
thaw:
thaw_processes();
+enable_cpus:
enable_nonboot_cpus();
pm_restore_console();
return error;