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PM: disable usermode helper before hibernation and suspend 

Use a hibernation and suspend notifier to disable the user mode helper before
a hibernation/suspend and enable it after the operation.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Rafael J. Wysocki 2007-07-19 01:47:36 -07:00 committed by Linus Torvalds
parent b10d911749
commit 8cdd4936c1
1 changed files with 30 additions and 1 deletions
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31
kernel/kmod.c
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@ -33,12 +33,22 @@
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/resource.h>
#include <linux/notifier.h>
#include <linux/suspend.h>
#include <asm/uaccess.h>
extern int max_threads;
static struct workqueue_struct *khelper_wq;
/*
* If set, both call_usermodehelper_keys() and call_usermodehelper_pipe() exit
* immediately returning -EBUSY. Used for preventing user land processes from
* being created after the user land has been frozen during a system-wide
* hibernation or suspend operation.
*/
static int usermodehelper_disabled;
#ifdef CONFIG_KMOD
/*
@ -265,6 +275,24 @@ static void __call_usermodehelper(struct work_struct *work)
}
}
static int usermodehelper_pm_callback(struct notifier_block *nfb,
unsigned long action,
void *ignored)
{
switch (action) {
case PM_HIBERNATION_PREPARE:
case PM_SUSPEND_PREPARE:
usermodehelper_disabled = 1;
return NOTIFY_OK;
case PM_POST_HIBERNATION:
case PM_POST_SUSPEND:
usermodehelper_disabled = 0;
return NOTIFY_OK;
}
return NOTIFY_DONE;
}
/**
* call_usermodehelper_setup - prepare to call a usermode helper
* @path - path to usermode executable
@ -374,7 +402,7 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info,
goto out;
}
if (!khelper_wq) {
if (!khelper_wq || usermodehelper_disabled) {
retval = -EBUSY;
goto out;
}
@ -431,4 +459,5 @@ void __init usermodehelper_init(void)
{
khelper_wq = create_singlethread_workqueue("khelper");
BUG_ON(!khelper_wq);
pm_notifier(usermodehelper_pm_callback, 0);
}