ipv6: ipv6_chk_custom_prefix() rcu conversion

Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/addrconf.c

@@ -1859,20 +1859,18 @@ static bool ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
 bool ipv6_chk_custom_prefix(const struct in6_addr *addr,
 	const unsigned int prefix_len, struct net_device *dev)
 {
-	struct inet6_dev *idev;
-	struct inet6_ifaddr *ifa;
+	const struct inet6_ifaddr *ifa;
+	const struct inet6_dev *idev;
 	bool ret = false;
 
 	rcu_read_lock();
 	idev = __in6_dev_get(dev);
 	if (idev) {
-		read_lock_bh(&idev->lock);
-		list_for_each_entry(ifa, &idev->addr_list, if_list) {
+		list_for_each_entry_rcu(ifa, &idev->addr_list, if_list) {
 			ret = ipv6_prefix_equal(addr, &ifa->addr, prefix_len);
 			if (ret)
 				break;
 		}
-		read_unlock_bh(&idev->lock);
 	}
 	rcu_read_unlock();