ipv6: Replace inet6_ifaddr->dead with state

This patch replaces the boolean dead flag on inet6_ifaddr with
a state enum.  This allows us to roll back changes when deleting
an address according to whether DAD has completed or not.

This patch only adds the state field and does not change the logic.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/if_inet6.h

@@ -32,6 +32,13 @@
 
 #ifdef __KERNEL__
 
+enum {
+	INET6_IFADDR_STATE_DAD,
+	INET6_IFADDR_STATE_POSTDAD,
+	INET6_IFADDR_STATE_UP,
+	INET6_IFADDR_STATE_DEAD,
+};
+
 struct inet6_ifaddr {
 	struct in6_addr		addr;
 	__u32			prefix_len;
@@ -40,6 +47,9 @@ struct inet6_ifaddr {
 	__u32			prefered_lft;
 	atomic_t		refcnt;
 	spinlock_t		lock;
+	spinlock_t		state_lock;
+
+	int			state;
 
 	__u8			probes;
 	__u8			flags;
@@ -62,8 +72,6 @@ struct inet6_ifaddr {
 	struct inet6_ifaddr	*ifpub;
 	int			regen_count;
 #endif
-
-	int			dead;
 	struct rcu_head		rcu;
 };
 

net/ipv6/addrconf.c

@@ -553,7 +553,7 @@ void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp)
 	if (del_timer(&ifp->timer))
 		pr_notice("Timer is still running, when freeing ifa=%p\n", ifp);
 
-	if (!ifp->dead) {
+	if (ifp->state != INET6_IFADDR_STATE_DEAD) {
 		pr_warning("Freeing alive inet6 address %p\n", ifp);
 		return;
 	}
@@ -648,6 +648,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen,
 	ipv6_addr_copy(&ifa->addr, addr);
 
 	spin_lock_init(&ifa->lock);
+	spin_lock_init(&ifa->state_lock);
 	init_timer(&ifa->timer);
 	INIT_HLIST_NODE(&ifa->addr_lst);
 	ifa->timer.data = (unsigned long) ifa;
@@ -720,7 +721,7 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
 
 	hash = ipv6_addr_hash(&ifp->addr);
 
-	ifp->dead = 1;
+	ifp->state = INET6_IFADDR_STATE_DEAD;
 
 	spin_lock_bh(&addrconf_hash_lock);
 	hlist_del_init_rcu(&ifp->addr_lst);
@@ -2665,7 +2666,7 @@ static int addrconf_ifdown(struct net_device *dev, int how)
 		ifa = list_first_entry(&idev->tempaddr_list,
 				       struct inet6_ifaddr, tmp_list);
 		list_del(&ifa->tmp_list);
-		ifa->dead = 1;
+		ifa->state = INET6_IFADDR_STATE_DEAD;
 		write_unlock_bh(&idev->lock);
 		spin_lock_bh(&ifa->lock);
 
@@ -2707,7 +2708,7 @@ static int addrconf_ifdown(struct net_device *dev, int how)
 			write_unlock_bh(&idev->lock);
 		} else {
 			list_del(&ifa->if_list);
-			ifa->dead = 1;
+			ifa->state = INET6_IFADDR_STATE_DEAD;
 			write_unlock_bh(&idev->lock);
 
 			/* clear hash table */
@@ -2717,7 +2718,7 @@ static int addrconf_ifdown(struct net_device *dev, int how)
 		}
 
 		__ipv6_ifa_notify(RTM_DELADDR, ifa);
-		if (ifa->dead)
+		if (ifa->state == INET6_IFADDR_STATE_DEAD)
 			atomic_notifier_call_chain(&inet6addr_chain,
 						   NETDEV_DOWN, ifa);
 		in6_ifa_put(ifa);
@@ -2815,7 +2816,7 @@ static void addrconf_dad_start(struct inet6_ifaddr *ifp, u32 flags)
 	net_srandom(ifp->addr.s6_addr32[3]);
 
 	read_lock_bh(&idev->lock);
-	if (ifp->dead)
+	if (ifp->state == INET6_IFADDR_STATE_DEAD)
 		goto out;
 
 	spin_lock(&ifp->lock);
@@ -4050,7 +4051,8 @@ static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
 		addrconf_leave_solict(ifp->idev, &ifp->addr);
 		dst_hold(&ifp->rt->u.dst);
 
-		if (ifp->dead && ip6_del_rt(ifp->rt))
+		if (ifp->state == INET6_IFADDR_STATE_DEAD &&
+		    ip6_del_rt(ifp->rt))
 			dst_free(&ifp->rt->u.dst);
 		break;
 	}