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>

1 files changed, 5 insertions, 1 deletions

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;
 }