Commit 1e73203c authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
parent 7b5179ac

kernel/power/hibernate.c

+0 −11
Original line number Diff line number Diff line
@@ -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);

kernel/power/process.c

+7 −0
Original line number Diff line number Diff line
@@ -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");

}

kernel/power/suspend.c

+0 −7
Original line number Diff line number Diff line
@@ -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();

}

kernel/power/user.c

+1 −9
Original line number Diff line number Diff line
@@ -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;

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