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

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>

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 12334ee412cab6c84e76c958937b111ed64cb1e9..a364144ad336fb5cf55bcb6f78dbb1e718080637 100644 (file)
--- 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);

diff --git a/kernel/power/process.c b/kernel/power/process.c
index 7e426459e60a21633d8eeff0d9751455303bdf97..0d20bc0455d5bf2682e1c7f33dc4e3956edb3528 100644 (file)
--- 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");
 }

diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 4fd51beed87955f938f7b6545e49ffec0430da56..038d72bc59f53eebf4a3fe96c61449f9310488ef 100644 (file)
--- 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_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 3e100075b13cb6ab449034af458266e20dcaa369..89dc7e4525440a3e3eef2481731aeb210fda97a4 100644 (file)
--- 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 *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;