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authorRafael J. Wysocki <rjw@sisk.pl>2006-09-25 23:32:48 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-26 08:48:59 -0700
commite3920fb42c8ddfe63befb54d95c0e13eabacea9b (patch)
tree08371a71e58e6e9d3ec62dfa6a22b3b5e6ff0fd5 /kernel/power
parente8eff5ac294e12531c4195e0c15a222d3c9015e5 (diff)
[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>
Diffstat (limited to 'kernel/power')
-rw-r--r--kernel/power/Makefile2
-rw-r--r--kernel/power/disk.c7
-rw-r--r--kernel/power/main.c10
-rw-r--r--kernel/power/smp.c62
-rw-r--r--kernel/power/user.c14
5 files changed, 19 insertions, 76 deletions
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 8d0af3d37a4..38725f526af 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -7,6 +7,4 @@ obj-y := main.o process.o console.o
obj-$(CONFIG_PM_LEGACY) += pm.o
obj-$(CONFIG_SOFTWARE_SUSPEND) += swsusp.o disk.o snapshot.o swap.o user.o
-obj-$(CONFIG_SUSPEND_SMP) += smp.o
-
obj-$(CONFIG_MAGIC_SYSRQ) += poweroff.o
diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index e13e7406784..7c7b9b65e36 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 @@ static int prepare_processes(void)
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 @@ static int prepare_processes(void)
return 0;
thaw:
thaw_processes();
+enable_cpus:
enable_nonboot_cpus();
pm_restore_console();
return error;
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 6d295c77679..4d403323a7b 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -16,6 +16,7 @@
#include <linux/init.h>
#include <linux/pm.h>
#include <linux/console.h>
+#include <linux/cpu.h>
#include "power.h"
@@ -51,7 +52,7 @@ void pm_set_ops(struct pm_ops * ops)
static int suspend_prepare(suspend_state_t state)
{
- int error = 0;
+ int error;
unsigned int free_pages;
if (!pm_ops || !pm_ops->enter)
@@ -59,12 +60,9 @@ static int suspend_prepare(suspend_state_t state)
pm_prepare_console();
- disable_nonboot_cpus();
-
- if (num_online_cpus() != 1) {
- error = -EPERM;
+ error = disable_nonboot_cpus();
+ if (error)
goto Enable_cpu;
- }
if (freeze_processes()) {
error = -EAGAIN;
diff --git a/kernel/power/smp.c b/kernel/power/smp.c
deleted file mode 100644
index 5957312b2d6..00000000000
--- a/kernel/power/smp.c
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- * drivers/power/smp.c - Functions for stopping other CPUs.
- *
- * Copyright 2004 Pavel Machek <pavel@suse.cz>
- * Copyright (C) 2002-2003 Nigel Cunningham <ncunningham@clear.net.nz>
- *
- * This file is released under the GPLv2.
- */
-
-#undef DEBUG
-
-#include <linux/smp_lock.h>
-#include <linux/interrupt.h>
-#include <linux/suspend.h>
-#include <linux/module.h>
-#include <linux/cpu.h>
-#include <asm/atomic.h>
-#include <asm/tlbflush.h>
-
-/* This is protected by pm_sem semaphore */
-static cpumask_t frozen_cpus;
-
-void disable_nonboot_cpus(void)
-{
- int cpu, error;
-
- error = 0;
- cpus_clear(frozen_cpus);
- printk("Freezing cpus ...\n");
- for_each_online_cpu(cpu) {
- if (cpu == 0)
- continue;
- error = cpu_down(cpu);
- if (!error) {
- cpu_set(cpu, frozen_cpus);
- printk("CPU%d is down\n", cpu);
- continue;
- }
- printk("Error taking cpu %d down: %d\n", cpu, error);
- }
- BUG_ON(raw_smp_processor_id() != 0);
- if (error)
- panic("cpus not sleeping");
-}
-
-void enable_nonboot_cpus(void)
-{
- int cpu, error;
-
- printk("Thawing cpus ...\n");
- for_each_cpu_mask(cpu, frozen_cpus) {
- error = cpu_up(cpu);
- if (!error) {
- printk("CPU%d is up\n", cpu);
- continue;
- }
- printk("Error taking cpu %d up: %d\n", cpu, error);
- panic("Not enough cpus");
- }
- cpus_clear(frozen_cpus);
-}
-
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 3f1539fbe48..0ef5e4ba39e 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -19,6 +19,7 @@
#include <linux/swapops.h>
#include <linux/pm.h>
#include <linux/fs.h>
+#include <linux/cpu.h>
#include <asm/uaccess.h>
@@ -139,12 +140,15 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
if (data->frozen)
break;
down(&pm_sem);
- disable_nonboot_cpus();
- if (freeze_processes()) {
- thaw_processes();
- enable_nonboot_cpus();
- error = -EBUSY;
+ error = disable_nonboot_cpus();
+ if (!error) {
+ error = freeze_processes();
+ if (error) {
+ thaw_processes();
+ error = -EBUSY;
+ }
}
+ enable_nonboot_cpus();
up(&pm_sem);
if (!error)
data->frozen = 1;