ipv6: route: make rtm_getroute not assume rtnl is locked

__dev_get_by_index assumes RTNL is held, use _rcu version instead.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -3611,8 +3611,11 @@ static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 		struct net_device *dev;
 		int flags = 0;
 
-		dev = __dev_get_by_index(net, iif);
+		rcu_read_lock();
+
+		dev = dev_get_by_index_rcu(net, iif);
 		if (!dev) {
+			rcu_read_unlock();
 			err = -ENODEV;
 			goto errout;
 		}
@@ -3624,6 +3627,8 @@ static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 
 		if (!fibmatch)
 			dst = ip6_route_input_lookup(net, dev, &fl6, flags);
+
+		rcu_read_unlock();
 	} else {
 		fl6.flowi6_oif = oif;