if (!unregister) return;  
static void xfrm_dst_ifdown(struct dst_entry *dst, struct net_device *dev,			    int unregister){	if (!unregister)		return;	while ((dst = dst->child) && dst->xfrm && dst->dev == dev) {		dst->dev = &loopback_dev;		dev_hold(&loopback_dev);		dev_put(dev);	}}
10457	/local/tlutelli/issta_data/temp/c/2005_temp/2005/10457/aabc9761b69f1bfa30a78f7005be95cc9cc06175/xfrm_policy.c/clean/net/xfrm/xfrm_policy.c