Index: sys/netinet/tcp_input.c
===================================================================
--- sys/netinet/tcp_input.c
+++ sys/netinet/tcp_input.c
@@ -3957,9 +3957,7 @@
 	 * (del_data) and an estimate of how many bytes are in the
 	 * network.
 	 */
-	if (SEQ_GEQ(th->th_ack, tp->snd_una))
-		del_data = BYTES_THIS_ACK(tp, th);
-	del_data += tp->sackhint.delivered_data;
+	del_data = tp->sackhint.delivered_data;
 	pipe = (tp->snd_nxt - tp->snd_fack) + tp->sackhint.sack_bytes_rexmit;
 	tp->sackhint.prr_delivered += del_data;
 	/*