ipv4: Restart rt_intern_hash after emergency rebuild (v2)

The the rebuild changes the genid which in turn is used at
the hash calculation. Thus if we don't restart and go on with
inserting the rt will happen in wrong chain.

(Fixed Neil's comment about the index passed into the rt_intern_hash)

Signed-off-by: Pavel Emelyanov <[e-mail]>
Reviewed-by: Neil Horman <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv4/route.c

···
 }
 
 static int rt_intern_hash(unsigned hash, struct rtable *rt,
-			  struct rtable **rp, struct sk_buff *skb)
+			  struct rtable **rp, struct sk_buff *skb, int ifindex)
 {
 	struct rtable	*rth, **rthp;
 	unsigned long	now;
···
 					rt->u.dst.dev->name, num);
 			}
 			rt_emergency_hash_rebuild(net);
+			spin_unlock_bh(rt_hash_lock_addr(hash));
+
+			hash = rt_hash(rt->fl.fl4_dst, rt->fl.fl4_src,
+					ifindex, rt_genid(net));
+			goto restart;
 		}
 	}
 
···
 							&netevent);
 
 				rt_del(hash, rth);
-				if (!rt_intern_hash(hash, rt, &rt, NULL))
+				if (!rt_intern_hash(hash, rt, &rt, NULL, rt->fl.oif))
 					ip_rt_put(rt);
 				goto do_next;
 			}
···
 
 	in_dev_put(in_dev);
 	hash = rt_hash(daddr, saddr, dev->ifindex, rt_genid(dev_net(dev)));
-	return rt_intern_hash(hash, rth, NULL, skb);
+	return rt_intern_hash(hash, rth, NULL, skb, dev->ifindex);
 
 e_nobufs:
 	in_dev_put(in_dev);
···
 	/* put it into the cache */
 	hash = rt_hash(daddr, saddr, fl->iif,
 		       rt_genid(dev_net(rth->u.dst.dev)));
-	return rt_intern_hash(hash, rth, NULL, skb);
+	return rt_intern_hash(hash, rth, NULL, skb, fl->iif);
 }
 
 /*
···
 	}
 	rth->rt_type	= res.type;
 	hash = rt_hash(daddr, saddr, fl.iif, rt_genid(net));
-	err = rt_intern_hash(hash, rth, NULL, skb);
+	err = rt_intern_hash(hash, rth, NULL, skb, fl.iif);
 	goto done;
 
 no_route:
···
 	if (err == 0) {
 		hash = rt_hash(oldflp->fl4_dst, oldflp->fl4_src, oldflp->oif,
 			       rt_genid(dev_net(dev_out)));
-		err = rt_intern_hash(hash, rth, rp, NULL);
+		err = rt_intern_hash(hash, rth, rp, NULL, oldflp->oif);
 	}
 
 	return err;