synclink_gt fix module reference

Get module reference on open() by generic HDLC to prevent module from
unloading while interface is active.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/synclink_gt.c

@@ -1565,6 +1565,9 @@ static int hdlcdev_open(struct net_device *dev)
 	int rc;
 	unsigned long flags;
 
+	if (!try_module_get(THIS_MODULE))
+		return -EBUSY;
+
 	DBGINFO(("%s hdlcdev_open\n", dev->name));
 
 	/* generic HDLC layer open processing */
@@ -1634,6 +1637,7 @@ static int hdlcdev_close(struct net_device *dev)
 	info->netcount=0;
 	spin_unlock_irqrestore(&info->netlock, flags);
 
+	module_put(THIS_MODULE);
 	return 0;
 }