PM / Sleep: Move disabling of usermode helpers to the freezer

The core suspend/hibernation code calls usermodehelper_disable() to
avoid race conditions between the freezer and the starting of
usermode helpers and each code path has to do that on its own.
However, it is always called right before freeze_processes()
and usermodehelper_enable() is always called right after
thaw_processes().  For this reason, to avoid code duplication and
to make the connection between usermodehelper_disable() and the
freezer more visible, make freeze_processes() call it and remove the
direct usermodehelper_disable() and usermodehelper_enable() calls
from all suspend/hibernation code paths.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
This commit is contained in:
Rafael J. Wysocki 2012-03-28 23:30:21 +02:00
parent 7b5179ac14
commit 1e73203cd1
4 changed files with 8 additions and 27 deletions

View File

@ -16,7 +16,6 @@
#include <linux/string.h>
#include <linux/device.h>
#include <linux/async.h>
#include <linux/kmod.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/mount.h>
@ -620,10 +619,6 @@ int hibernate(void)
sys_sync();
printk("done.\n");
error = usermodehelper_disable();
if (error)
goto Exit;
error = freeze_processes();
if (error)
goto Free_bitmaps;
@ -660,7 +655,6 @@ int hibernate(void)
freezer_test_done = false;
Free_bitmaps:
usermodehelper_enable();
free_basic_memory_bitmaps();
Exit:
pm_notifier_call_chain(PM_POST_HIBERNATION);
@ -780,10 +774,6 @@ static int software_resume(void)
if (error)
goto close_finish;
error = usermodehelper_disable();
if (error)
goto close_finish;
pr_debug("PM: Preparing processes for restore.\n");
error = freeze_processes();
if (error) {
@ -802,7 +792,6 @@ static int software_resume(void)
swsusp_free();
thaw_processes();
Done:
usermodehelper_enable();
free_basic_memory_bitmaps();
Finish:
pm_notifier_call_chain(PM_POST_RESTORE);

View File

@ -16,6 +16,7 @@
#include <linux/freezer.h>
#include <linux/delay.h>
#include <linux/workqueue.h>
#include <linux/kmod.h>
/*
* Timeout for stopping processes
@ -122,6 +123,10 @@ int freeze_processes(void)
{
int error;
error = usermodehelper_disable();
if (error)
return error;
if (!pm_freezing)
atomic_inc(&system_freezing_cnt);
@ -187,6 +192,8 @@ void thaw_processes(void)
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
usermodehelper_enable();
schedule();
printk("done.\n");
}

View File

@ -12,7 +12,6 @@
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/syscalls.h>
@ -102,17 +101,12 @@ static int suspend_prepare(void)
if (error)
goto Finish;
error = usermodehelper_disable();
if (error)
goto Finish;
error = suspend_freeze_processes();
if (!error)
return 0;
suspend_stats.failed_freeze++;
dpm_save_failed_step(SUSPEND_FREEZE);
usermodehelper_enable();
Finish:
pm_notifier_call_chain(PM_POST_SUSPEND);
pm_restore_console();
@ -259,7 +253,6 @@ int suspend_devices_and_enter(suspend_state_t state)
static void suspend_finish(void)
{
suspend_thaw_processes();
usermodehelper_enable();
pm_notifier_call_chain(PM_POST_SUSPEND);
pm_restore_console();
}

View File

@ -12,7 +12,6 @@
#include <linux/suspend.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
#include <linux/kmod.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
@ -222,14 +221,8 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
sys_sync();
printk("done.\n");
error = usermodehelper_disable();
if (error)
break;
error = freeze_processes();
if (error)
usermodehelper_enable();
else
if (!error)
data->frozen = 1;
break;
@ -238,7 +231,6 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
break;
pm_restore_gfp_mask();
thaw_processes();
usermodehelper_enable();
data->frozen = 0;
break;