From e3920fb42c8ddfe63befb54d95c0e13eabacea9b Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 25 Sep 2006 23:32:48 -0700 Subject: [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 Acked-by: Pavel Machek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/power/Makefile | 2 -- kernel/power/disk.c | 7 +++++- kernel/power/main.c | 10 ++++----- kernel/power/smp.c | 62 --------------------------------------------------- kernel/power/user.c | 14 +++++++----- 5 files changed, 19 insertions(+), 76 deletions(-) delete mode 100644 kernel/power/smp.c (limited to 'kernel/power') diff --git a/kernel/power/Makefile b/kernel/power/Makefile index 8d0af3d37a4b..38725f526afc 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 e13e74067845..7c7b9b65e365 100644 --- a/kernel/power/disk.c +++ b/kernel/power/disk.c @@ -18,6 +18,7 @@ #include #include #include +#include #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 6d295c776794..4d403323a7bb 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -16,6 +16,7 @@ #include #include #include +#include #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 5957312b2d68..000000000000 --- a/kernel/power/smp.c +++ /dev/null @@ -1,62 +0,0 @@ -/* - * drivers/power/smp.c - Functions for stopping other CPUs. - * - * Copyright 2004 Pavel Machek - * Copyright (C) 2002-2003 Nigel Cunningham - * - * This file is released under the GPLv2. - */ - -#undef DEBUG - -#include -#include -#include -#include -#include -#include -#include - -/* 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 3f1539fbe48a..0ef5e4ba39e5 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -19,6 +19,7 @@ #include #include #include +#include #include @@ -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; -- cgit v1.2.3