patches.runtime_pm/0016-PM-Runtime-Prevent-runtime_resume-from-racing-with-p.patch

From 296795de8932876abe22dfe91d6689257a1a9731 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern@rowland.harvard.edu>
Date: Wed, 6 Jul 2011 10:52:23 +0200
Subject: PM / Runtime: Prevent runtime_resume from racing with probe

This patch (as1475) adds device_lock() and device_unlock() calls to
the store methods for the power/control and power/autosuspend_delay_ms
sysfs attribute files.  We don't want badly timed writes to these
files to cause runtime_resume callbacks to occur while a driver is
being probed for a device.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
(cherry picked from commit 69c843b45eb3b8f267019e6a05860c9c48337419)

Signed-off-by: Simon Horman <horms@verge.net.au>
---
 drivers/base/power/sysfs.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index a9f5b89..942d6a7 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -116,12 +116,14 @@ static ssize_t control_store(struct device * dev, struct device_attribute *attr,
 	cp = memchr(buf, '\n', n);
 	if (cp)
 		len = cp - buf;
+	device_lock(dev);
 	if (len == sizeof ctrl_auto - 1 && strncmp(buf, ctrl_auto, len) == 0)
 		pm_runtime_allow(dev);
 	else if (len == sizeof ctrl_on - 1 && strncmp(buf, ctrl_on, len) == 0)
 		pm_runtime_forbid(dev);
 	else
-		return -EINVAL;
+		n = -EINVAL;
+	device_unlock(dev);
 	return n;
 }
 
@@ -205,7 +207,9 @@ static ssize_t autosuspend_delay_ms_store(struct device *dev,
 	if (strict_strtol(buf, 10, &delay) != 0 || delay != (int) delay)
 		return -EINVAL;
 
+	device_lock(dev);
 	pm_runtime_set_autosuspend_delay(dev, delay);
+	device_unlock(dev);
 	return n;
 }
 
-- 
1.7.10.1.362.g242cab3