linux-kernel - [ 39/48] PM / Sleep: Prevent waiting forever on asynchronous suspend after abort

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Date:	Sun, 01 Jul 2012 18:20:45 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk, Mandeep Singh Baines <msb@...omium.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: [ 39/48] PM / Sleep: Prevent waiting forever on asynchronous suspend after
 abort

3.2-stable review patch.  If anyone has any objections, please let me know.

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

From: Mandeep Singh Baines <msb@...omium.org>

commit 1f758b23177d588a71b96ad02990e715949bb82f upstream.

__device_suspend() must always send a completion. Otherwise, parent
devices will wait forever.

Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
system sleep (v2)", introduced a regression by short-circuiting the
complete_all() for certain error cases.

This patch fixes the bug by always signalling a completion.

Addresses http://crosbug.com/31972

Tested by injecting an abort.

Signed-off-by: Mandeep Singh Baines <msb@...omium.org>
Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/base/power/main.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index e0fb5b0..9cb845e 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1031,7 +1031,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	dpm_wait_for_children(dev, async);
 
 	if (async_error)
-		return 0;
+		goto Complete;
 
 	pm_runtime_get_noresume(dev);
 	if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
@@ -1040,7 +1040,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	if (pm_wakeup_pending()) {
 		pm_runtime_put_sync(dev);
 		async_error = -EBUSY;
-		return 0;
+		goto Complete;
 	}
 
 	device_lock(dev);
@@ -1097,6 +1097,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	}
 
 	device_unlock(dev);
+
+ Complete:
 	complete_all(&dev->power.completion);
 
 	if (error) {


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