usb_wwan: fix error in marking device busy

This fixes two errors:
- the device is busy if a message was recieved even if resubmission fails
- the device is not busy if resubmission fails due to -EPERM
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/usb_wwan.c

@@ -305,12 +305,17 @@ static void usb_wwan_indat_callback(struct urb *urb)
 		/* Resubmit urb so we continue receiving */
 		if (status != -ESHUTDOWN) {
 			err = usb_submit_urb(urb, GFP_ATOMIC);
-			if (err && err != -EPERM)
+			if (err) {
+				if (err != -EPERM) {
 					printk(KERN_ERR "%s: resubmit read urb failed. "
 						"(%d)", __func__, err);
-			else
+					/* busy also in error unless we are killed */
+					usb_mark_last_busy(port->serial->dev);
+				}
+			} else {
 				usb_mark_last_busy(port->serial->dev);
 			}
+		}
 
 	}
 }