Index: sys/netinet/tcp_stacks/fastpath.c
===================================================================
--- sys/netinet/tcp_stacks/fastpath.c	(revision 293312)
+++ sys/netinet/tcp_stacks/fastpath.c	(working copy)
@@ -164,7 +164,7 @@
 #define DELAY_ACK(tp, tlen)						\
 	((!tcp_timer_active(tp, TT_DELACK) &&				\
 	    (tp->t_flags & TF_RXWIN0SENT) == 0) &&			\
-	    (tlen <= tp->t_maxopd) &&					\
+	    (tlen <= tp->t_maxseg) &&					\
 	    (V_tcp_delack_enabled || (tp->t_flags & TF_NEEDSYN)))
 
 /*