5 files changed, 58 insertions, 38 deletions

diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index a1a91577813c..92213a9194e1 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -99,4 +99,7 @@ struct file;
 extern int call_usermodehelper_pipe(char *path, char *argv[], char *envp[],
                                     struct file **filp);
 
+extern int usermodehelper_disable(void);
+extern void usermodehelper_enable(void);
+
 #endif /* __LINUX_KMOD_H__ */
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 2456d1a0befb..ab7dd08472fc 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -265,7 +265,7 @@ static void __call_usermodehelper(struct work_struct *work)
         }
 }
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 /*
  * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY
  * (used for preventing user land processes from being created after the user
@@ -288,39 +288,37 @@ static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
  */
 #define RUNNING_HELPERS_TIMEOUT (5 * HZ)
 
-static int usermodehelper_pm_callback(struct notifier_block *nfb,
-                                        unsigned long action,
-                                        void *ignored)
+/**
+ * usermodehelper_disable - prevent new helpers from being started
+ */
+int usermodehelper_disable(void)
 {
         long retval;
 
-        switch (action) {
-        case PM_HIBERNATION_PREPARE:
-        case PM_SUSPEND_PREPARE:
-                usermodehelper_disabled = 1;
-                smp_mb();
-                /*
-                 * From now on call_usermodehelper_exec() won't start any new
-                 * helpers, so it is sufficient if running_helpers turns out to
-                 * be zero at one point (it may be increased later, but that
-                 * doesn't matter).
-                 */
-                retval = wait_event_timeout(running_helpers_waitq,
+        usermodehelper_disabled = 1;
+        smp_mb();
+        /*
+         * From now on call_usermodehelper_exec() won't start any new
+         * helpers, so it is sufficient if running_helpers turns out to
+         * be zero at one point (it may be increased later, but that
+         * doesn't matter).
+         */
+        retval = wait_event_timeout(running_helpers_waitq,
                                         atomic_read(&running_helpers) == 0,
                                         RUNNING_HELPERS_TIMEOUT);
-                if (retval) {
-                        return NOTIFY_OK;
-                } else {
-                        usermodehelper_disabled = 0;
-                        return NOTIFY_BAD;
-                }
-        case PM_POST_HIBERNATION:
-        case PM_POST_SUSPEND:
-                usermodehelper_disabled = 0;
-                return NOTIFY_OK;
-        }
+        if (retval)
+                return 0;
 
-        return NOTIFY_DONE;
+        usermodehelper_disabled = 0;
+        return -EAGAIN;
+}
+
+/**
+ * usermodehelper_enable - allow new helpers to be started again
+ */
+void usermodehelper_enable(void)
+{
+        usermodehelper_disabled = 0;
 }
 
 static void helper_lock(void)
@@ -334,18 +332,12 @@ static void helper_unlock(void)
         if (atomic_dec_and_test(&running_helpers))
                 wake_up(&running_helpers_waitq);
 }
-
-static void register_pm_notifier_callback(void)
-{
-        pm_notifier(usermodehelper_pm_callback, 0);
-}
-#else /* CONFIG_PM */
+#else /* CONFIG_PM_SLEEP */
 #define usermodehelper_disabled 0
 
 static inline void helper_lock(void) {}
 static inline void helper_unlock(void) {}
-static inline void register_pm_notifier_callback(void) {}
-#endif /* CONFIG_PM */
+#endif /* CONFIG_PM_SLEEP */
 
 /**
  * call_usermodehelper_setup - prepare to call a usermode helper
@@ -515,5 +507,4 @@ void __init usermodehelper_init(void)
 {
         khelper_wq = create_singlethread_workqueue("khelper");
         BUG_ON(!khelper_wq);
-        register_pm_notifier_callback();
 }
diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index bbd85c60f741..331f9836383f 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -14,6 +14,7 @@
 #include <linux/reboot.h>
 #include <linux/string.h>
 #include <linux/device.h>
+#include <linux/kmod.h>
 #include <linux/delay.h>
 #include <linux/fs.h>
 #include <linux/mount.h>
@@ -520,6 +521,10 @@ int hibernate(void)
         if (error)
                 goto Exit;
 
+        error = usermodehelper_disable();
+        if (error)
+                goto Exit;
+
         /* Allocate memory management structures */
         error = create_basic_memory_bitmaps();
         if (error)
@@ -558,6 +563,7 @@ int hibernate(void)
         thaw_processes();
  Finish:
         free_basic_memory_bitmaps();
+        usermodehelper_enable();
  Exit:
         pm_notifier_call_chain(PM_POST_HIBERNATION);
         pm_restore_console();
@@ -634,6 +640,10 @@ static int software_resume(void)
         if (error)
                 goto Finish;
 
+        error = usermodehelper_disable();
+        if (error)
+                goto Finish;
+
         error = create_basic_memory_bitmaps();
         if (error)
                 goto Finish;
@@ -656,6 +666,7 @@ static int software_resume(void)
         thaw_processes();
  Done:
         free_basic_memory_bitmaps();
+        usermodehelper_enable();
  Finish:
         pm_notifier_call_chain(PM_POST_RESTORE);
         pm_restore_console();
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 540b16b68565..19122cf6d827 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -14,6 +14,7 @@
 #include <linux/string.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
+#include <linux/kmod.h>
 #include <linux/init.h>
 #include <linux/console.h>
 #include <linux/cpu.h>
@@ -237,6 +238,10 @@ static int suspend_prepare(void)
         if (error)
                 goto Finish;
 
+        error = usermodehelper_disable();
+        if (error)
+                goto Finish;
+
         if (suspend_freeze_processes()) {
                 error = -EAGAIN;
                 goto Thaw;
@@ -256,6 +261,7 @@ static int suspend_prepare(void)
 
  Thaw:
         suspend_thaw_processes();
+        usermodehelper_enable();
  Finish:
         pm_notifier_call_chain(PM_POST_SUSPEND);
         pm_restore_console();
@@ -376,6 +382,7 @@ 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();
 }
diff --git a/kernel/power/user.c b/kernel/power/user.c
index a6332a313262..005b93d839ba 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -212,13 +212,20 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
         case SNAPSHOT_FREEZE:
                 if (data->frozen)
                         break;
+
                 printk("Syncing filesystems ... ");
                 sys_sync();
                 printk("done.\n");
 
-                error = freeze_processes();
+                error = usermodehelper_disable();
                 if (error)
+                        break;
+
+                error = freeze_processes();
+                if (error) {
                         thaw_processes();
+                        usermodehelper_enable();
+                }
                 if (!error)
                         data->frozen = 1;
                 break;
@@ -227,6 +234,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
                 if (!data->frozen || data->ready)
                         break;
                 thaw_processes();
+                usermodehelper_enable();
                 data->frozen = 0;
                 break;