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Subject[ 44/78] PM / Sleep: Move disabling of usermode helpers to the freezer
3.3-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Rafael J. Wysocki" <rjw@sisk.pl>

commit 1e73203cd1157a03facc41ffb54050f5b28e55bd upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/power/hibernate.c | 11 -----------
kernel/power/process.c | 7 +++++++
kernel/power/suspend.c | 7 -------
kernel/power/user.c | 10 +---------
4 files changed, 8 insertions(+), 27 deletions(-)

--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -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>
@@ -618,10 +617,6 @@ int hibernate(void)
sys_sync();
printk("done.\n");

- error = usermodehelper_disable();
- if (error)
- goto Exit;
-
error = freeze_processes();
if (error)
goto Free_bitmaps;
@@ -658,7 +653,6 @@ int hibernate(void)
Thaw:
thaw_processes();
Free_bitmaps:
- usermodehelper_enable();
free_basic_memory_bitmaps();
Exit:
pm_notifier_call_chain(PM_POST_HIBERNATION);
@@ -778,10 +772,6 @@ 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) {
@@ -800,7 +790,6 @@ static int software_resume(void)
swsusp_free();
thaw_processes();
Done:
- usermodehelper_enable();
free_basic_memory_bitmaps();
Finish:
pm_notifier_call_chain(PM_POST_RESTORE);
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -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");
}
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -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>
@@ -101,17 +100,12 @@ 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_st
static void suspend_finish(void)
{
suspend_thaw_processes();
- usermodehelper_enable();
pm_notifier_call_chain(PM_POST_SUSPEND);
pm_restore_console();
}
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -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 *
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 *
break;
pm_restore_gfp_mask();
thaw_processes();
- usermodehelper_enable();
data->frozen = 0;
break;




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