USB: handle errors in power/level attribute

This patch (as906) improves the error handling for the USB power/level
attribute file.  If an error occurs, the original power-level settings
will be restored.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index e7c982377488..be37c863fdfb 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -232,12 +232,15 @@ set_level(struct device *dev, struct device_attribute *attr,
         int len = count;
         char *cp;
         int rc = 0;
+        int old_autosuspend_disabled, old_autoresume_disabled;
 
         cp = memchr(buf, '\n', count);
         if (cp)
                 len = cp - buf;
 
         usb_lock_device(udev);
+        old_autosuspend_disabled = udev->autosuspend_disabled;
+        old_autoresume_disabled = udev->autoresume_disabled;
 
         /* Setting the flags without calling usb_pm_lock is a subject to
          * races, but who cares...
@@ -263,6 +266,10 @@ set_level(struct device *dev, struct device_attribute *attr,
         } else
                 rc = -EINVAL;
 
+        if (rc) {
+                udev->autosuspend_disabled = old_autosuspend_disabled;
+                udev->autoresume_disabled = old_autoresume_disabled;
+        }
         usb_unlock_device(udev);
         return (rc < 0 ? rc : count);
 }