linux-kernel - [093/151] xen: improve error handling in do

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Date:	Wed, 16 Dec 2009 19:56:30 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Ian Campbell <ian.campbell@...rix.com>,
	Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
Subject: [093/151] xen: improve error handling in do_suspend.

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Ian Campbell <ian.campbell@...rix.com>

commit 65f63384b391bf4d384327d8a7c6de9860290b5c upstream.

The existing error handling has a few issues:
- If freeze_processes() fails it exits with shutting_down = SHUTDOWN_SUSPEND.
- If dpm_suspend_noirq() fails it exits without resuming xenbus.
- If stop_machine() fails it exits without resuming xenbus or calling
  dpm_resume_end().
- xs_suspend()/xs_resume() and dpm_suspend_noirq()/dpm_resume_noirq() were not
  nested in the obvious way.

Fix by ensuring each failure case goto's the correct label. Treat a failure of
stop_machine() as a cancelled suspend in order to follow the correct resume
path.

Signed-off-by: Ian Campbell <ian.campbell@...rix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/xen/manage.c |   20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -86,32 +86,32 @@ static void do_suspend(void)
 	err = freeze_processes();
 	if (err) {
 		printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
-		return;
+		goto out;
 	}
 #endif
 
 	err = dpm_suspend_start(PMSG_SUSPEND);
 	if (err) {
 		printk(KERN_ERR "xen suspend: dpm_suspend_start %d\n", err);
-		goto out;
+		goto out_thaw;
 	}
 
-	printk(KERN_DEBUG "suspending xenstore...\n");
-	xs_suspend();
-
 	err = dpm_suspend_noirq(PMSG_SUSPEND);
 	if (err) {
 		printk(KERN_ERR "dpm_suspend_noirq failed: %d\n", err);
-		goto resume_devices;
+		goto out_resume;
 	}
 
+	printk(KERN_DEBUG "suspending xenstore...\n");
+	xs_suspend();
+
 	err = stop_machine(xen_suspend, &cancelled, cpumask_of(0));
 
 	dpm_resume_noirq(PMSG_RESUME);
 
 	if (err) {
 		printk(KERN_ERR "failed to start xen_suspend: %d\n", err);
-		goto out;
+		cancelled = 1;
 	}
 
 	if (!cancelled) {
@@ -120,15 +120,17 @@ static void do_suspend(void)
 	} else
 		xs_suspend_cancel();
 
-resume_devices:
+out_resume:
 	dpm_resume_end(PMSG_RESUME);
 
 	/* Make sure timer events get retriggered on all CPUs */
 	clock_was_set();
-out:
+
+out_thaw:
 #ifdef CONFIG_PREEMPT
 	thaw_processes();
 #endif
+out:
 	shutting_down = SHUTDOWN_INVALID;
 }
 #endif	/* CONFIG_PM_SLEEP */


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