[IPV6]: Fix again the fl6_sock_lookup() fixed locking

YOSHIFUJI fairly pointed out, that the users increment should
be done under the ip6_sk_fl_lock not to give IPV6_FL_A_PUT a
chance to put this count to zero and release the flowlabel.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/ip6_flowlabel.c

@@ -210,9 +210,9 @@ struct ip6_flowlabel * fl6_sock_lookup(struct sock *sk, __be32 label)
 	for (sfl=np->ipv6_fl_list; sfl; sfl = sfl->next) {
 		struct ip6_flowlabel *fl = sfl->fl;
 		if (fl->label == label) {
-			read_unlock_bh(&ip6_sk_fl_lock);
 			fl->lastuse = jiffies;
 			atomic_inc(&fl->users);
+			read_unlock_bh(&ip6_sk_fl_lock);
 			return fl;
 		}
 	}