From: Alan Stern <stern@rowland.harvard.edu>
Date: Wed, 6 Jul 2011 08:52:23 +0000 (+0200)
Subject: PM / Runtime: Prevent runtime_resume from racing with probe
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=69c843b45eb3b8f267019e6a05860c9c48337419;p=linux-beck.git

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>
---

diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index a9f5b8979611..942d6a7c9ae1 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;
 }