---

yaml
---
r: 57824
b: refs/heads/master
c: 7769f40
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b9ce204f0a265f819d10c943a607746abb62f245
+refs/heads/master: 7769f4064cd9f4fbae09f071578a051aae83e844

trunk/net/ipv4/tcp_input.c

@@ -953,7 +953,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
 	int prior_fackets;
 	u32 lost_retrans = 0;
 	int flag = 0;
-	int dup_sack = 0;
+	int found_dup_sack = 0;
 	int cached_fack_count;
 	int i;
 	int first_sack_index;
@@ -964,20 +964,20 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
 
 	/* Check for D-SACK. */
 	if (before(ntohl(sp[0].start_seq), TCP_SKB_CB(ack_skb)->ack_seq)) {
-		dup_sack = 1;
+		found_dup_sack = 1;
 		tp->rx_opt.sack_ok |= 4;
 		NET_INC_STATS_BH(LINUX_MIB_TCPDSACKRECV);
 	} else if (num_sacks > 1 &&
 			!after(ntohl(sp[0].end_seq), ntohl(sp[1].end_seq)) &&
 			!before(ntohl(sp[0].start_seq), ntohl(sp[1].start_seq))) {
-		dup_sack = 1;
+		found_dup_sack = 1;
 		tp->rx_opt.sack_ok |= 4;
 		NET_INC_STATS_BH(LINUX_MIB_TCPDSACKOFORECV);
 	}
 
 	/* D-SACK for already forgotten data...
 	 * Do dumb counting. */
-	if (dup_sack &&
+	if (found_dup_sack &&
 			!after(ntohl(sp[0].end_seq), prior_snd_una) &&
 			after(ntohl(sp[0].end_seq), tp->undo_marker))
 		tp->undo_retrans--;
@@ -1058,6 +1058,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
 		__u32 start_seq = ntohl(sp->start_seq);
 		__u32 end_seq = ntohl(sp->end_seq);
 		int fack_count;
+		int dup_sack = (found_dup_sack && (i == first_sack_index));
 
 		skb = cached_skb;
 		fack_count = cached_fack_count;