linux-kernel - [PATCH 4/6] PM / Hibernate: Disable usermode helpers right before freezing tasks

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Date:	Mon, 26 Mar 2012 00:03:05 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	linux-kernel@...r.kernel.org
Cc:	Stephen Boyd <sboyd@...eaurora.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Saravana Kannan <skannan@...eaurora.org>,
	Kay Sievers <kay.sievers@...y.org>,
	Greg KH <gregkh@...uxfoundation.org>,
	Christian Lamparter <chunkeey@...glemail.com>,
	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
	alan@...rguk.ukuu.org.uk,
	Linux PM mailing list <linux-pm@...r.kernel.org>
Subject: [PATCH 4/6] PM / Hibernate: Disable usermode helpers right before freezing tasks

From: Rafael J. Wysocki <rjw@...k.pl>

There is no reason to call usermodehelper_disable() before creating
memory bitmaps in hibernate() and software_resume(), so call it right
before freeze_processes(), in accordance with the other suspend and
hibernation code.  Consequently, call usermodehelper_enable() right
after the thawing of tasks rather than after freeing the memory
bitmaps.

Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
---
 kernel/power/hibernate.c |   23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

Index: linux/kernel/power/hibernate.c
===================================================================
--- linux.orig/kernel/power/hibernate.c
+++ linux/kernel/power/hibernate.c
@@ -611,19 +611,19 @@ 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)
-		goto Enable_umh;
+		goto Exit;
 
 	printk(KERN_INFO "PM: Syncing filesystems ... ");
 	sys_sync();
 	printk("done.\n");
 
+	error = usermodehelper_disable();
+	if (error)
+		goto Exit;
+
 	error = freeze_processes();
 	if (error)
 		goto Free_bitmaps;
@@ -660,9 +660,8 @@ int hibernate(void)
 	freezer_test_done = false;
 
  Free_bitmaps:
-	free_basic_memory_bitmaps();
- Enable_umh:
 	usermodehelper_enable();
+	free_basic_memory_bitmaps();
  Exit:
 	pm_notifier_call_chain(PM_POST_HIBERNATION);
 	pm_restore_console();
@@ -777,15 +776,13 @@ static int software_resume(void)
 	if (error)
 		goto close_finish;
 
-	error = usermodehelper_disable();
+	error = create_basic_memory_bitmaps();
 	if (error)
 		goto close_finish;
 
-	error = create_basic_memory_bitmaps();
-	if (error) {
-		usermodehelper_enable();
+	error = usermodehelper_disable();
+	if (error)
 		goto close_finish;
-	}
 
 	pr_debug("PM: Preparing processes for restore.\n");
 	error = freeze_processes();
@@ -805,8 +802,8 @@ static int software_resume(void)
 	swsusp_free();
 	thaw_processes();
  Done:
-	free_basic_memory_bitmaps();
 	usermodehelper_enable();
+	free_basic_memory_bitmaps();
  Finish:
 	pm_notifier_call_chain(PM_POST_RESTORE);
 	pm_restore_console();

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