[ 3.5.y.z extended stable ] Patch "PM / QoS: fix wrong error-checking condition" has been added to staging queue

[Herton Ronaldo Krzesinski]

This is a note to let you know that I have just added a patch titled

    PM / QoS: fix wrong error-checking condition

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From eb68b338a00f2ff753bb1a9659dd3e42f8de8517 Mon Sep 17 00:00:00 2001
From: Guennadi Liakhovetski <g.liakhovetski at gmx.de>
Date: Fri, 23 Nov 2012 20:55:06 +0100
Subject: [PATCH] PM / QoS: fix wrong error-checking condition

commit a7227a0faa117d0bc532aea546ae5ac5f89e8ed7 upstream.

dev_pm_qos_add_request() can return 0, 1, or a negative error code,
therefore the correct error test is "if (error < 0)." Checking just for
non-zero return code leads to erroneous setting of the req->dev pointer
to NULL, which then leads to a repeated call to
dev_pm_qos_add_ancestor_request() in st1232_ts_irq_handler(). This in turn
leads to an Oops, when the I2C host adapter is unloaded and reloaded again
because of the inconsistent state of its QoS request list.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski at gmx.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 drivers/base/power/qos.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index fd849a2..b95ebf2 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -451,7 +451,7 @@ int dev_pm_qos_add_ancestor_request(struct device *dev,
 	if (ancestor)
 		error = dev_pm_qos_add_request(ancestor, req, value);

-	if (error)
+	if (error < 0)
 		req->dev = NULL;

 	return error;
--
1.7.9.5