2 files changed, 9 insertions, 1 deletions

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index c6b9f92e82..c072f88afb 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -333,6 +333,8 @@ struct tcp_sock {
 
         struct tcp_sack_block_wire recv_sack_cache[4];
 
+        u32     highest_sack;   /* Start seq of globally highest revd SACK (valid only in slowpath) */
+
         /* from STCP, retrans queue hinting */
         struct sk_buff* lost_skb_hint;
 
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index f893e90061..813f2049b8 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -979,8 +979,10 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
         int i;
         int first_sack_index;
 
-        if (!tp->sacked_out)
+        if (!tp->sacked_out) {
                 tp->fackets_out = 0;
+                tp->highest_sack = tp->snd_una;
+        }
         prior_fackets = tp->fackets_out;
 
         /* Check for D-SACK. */
@@ -1217,6 +1219,10 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
 
                                 if (fack_count > tp->fackets_out)
                                         tp->fackets_out = fack_count;
+
+                                if (after(TCP_SKB_CB(skb)->seq,
+                                    tp->highest_sack))
+                                        tp->highest_sack = TCP_SKB_CB(skb)->seq;
                         } else {
                                 if (dup_sack && (sacked&TCPCB_RETRANS))
                                         reord = min(fack_count, reord);