ipv6: ip6_route_output() never returns NULL.

ip6_route_output() never returns NULL, so it is wrong to
check if the return value is NULL.

Signed-off-by: RongQing.Li <roy.qing.li@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index c7e95c8..5aa3981 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -1926,8 +1926,10 @@
 	};
 
 	dst = ip6_route_output(net, NULL, &fl6);
-	if (!dst)
+	if (dst->error) {
+		dst_release(dst);
 		goto out_free;
+	}
 
 	skb_dst_drop(skb);
 	skb_dst_set(skb, dst);