[IPV6] leave subnet-routers anycast address during device deletion.

Signed-off-by: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>

include/net/addrconf.h

@@ -112,6 +112,7 @@ extern void ipv6_sock_ac_close(struct sock *sk);
 extern int inet6_ac_check(struct sock *sk, struct in6_addr *addr, int ifindex);
 
 extern int ipv6_dev_ac_inc(struct net_device *dev, struct in6_addr *addr);
+extern int __ipv6_dev_ac_dec(struct inet6_dev *idev, struct in6_addr *addr);
 extern int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr);
 extern int ipv6_chk_acast_addr(struct net_device *dev, struct in6_addr *addr);
 

net/ipv6/addrconf.c

@@ -3000,7 +3000,7 @@ static void ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
 
 			ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
 			if (!ipv6_addr_any(&addr))
-				ipv6_dev_ac_dec(ifp->idev->dev, &addr);
+				__ipv6_dev_ac_dec(ifp->idev, &addr);
 		}
 		dst_hold(&ifp->rt->u.dst);
 		if (ip6_del_rt(ifp->rt, NULL, NULL))

net/ipv6/anycast.c

@@ -377,15 +377,10 @@ int ipv6_dev_ac_inc(struct net_device *dev, struct in6_addr *addr)
 /*
  *	device anycast group decrement
  */
-int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr)
+int __ipv6_dev_ac_dec(struct inet6_dev *idev, struct in6_addr *addr)
 {
-	struct inet6_dev *idev;
 	struct ifacaddr6 *aca, *prev_aca;
 
-	idev = in6_dev_get(dev);
-	if (idev == NULL)
-		return -ENODEV;
-
 	write_lock_bh(&idev->lock);
 	prev_aca = NULL;
 	for (aca = idev->ac_list; aca; aca = aca->aca_next) {
@@ -395,12 +390,10 @@ int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr)
 	}
 	if (!aca) {
 		write_unlock_bh(&idev->lock);
-		in6_dev_put(idev);
 		return -ENOENT;
 	}
 	if (--aca->aca_users > 0) {
 		write_unlock_bh(&idev->lock);
-		in6_dev_put(idev);
 		return 0;
 	}
 	if (prev_aca)
@@ -417,10 +410,20 @@ int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr)
 		dst_release(&aca->aca_rt->u.dst);
 
 	aca_put(aca);
-	in6_dev_put(idev);
 	return 0;
 }
 
+int ipv6_dev_ac_dec(struct net_device *dev, struct in6_addr *addr)
+{
+	int ret;
+	struct inet6_dev *idev = in6_dev_get(dev);
+	if (idev == NULL)
+		return -ENODEV;
+	ret = __ipv6_dev_ac_dec(idev, addr);
+	in6_dev_put(idev);
+	return ret;
+}
+	
 /*
  *	check if the interface has this anycast address
  */