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>

diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index e7c9823..be37c86 100644 (file)
--- 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);
 }