1 files changed, 31 insertions, 35 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 7670ef968dce..870f53afd363 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -951,16 +951,43 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                 tp->fackets_out = 0;
         prior_fackets = tp->fackets_out;
 
+        /* Check for D-SACK. */
+        if (before(ntohl(sp[0].start_seq), TCP_SKB_CB(ack_skb)->ack_seq)) {
+                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;
+                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 &&
+                        !after(ntohl(sp[0].end_seq), prior_snd_una) &&
+                        after(ntohl(sp[0].end_seq), tp->undo_marker))
+                tp->undo_retrans--;
+
+        /* Eliminate too old ACKs, but take into
+         * account more or less fresh ones, they can
+         * contain valid SACK info.
+         */
+        if (before(TCP_SKB_CB(ack_skb)->ack_seq, prior_snd_una - tp->max_window))
+                return 0;
+
         /* SACK fastpath:
          * if the only SACK change is the increase of the end_seq of
          * the first block then only apply that SACK block
          * and use retrans queue hinting otherwise slowpath */
         flag = 1;
-        for (i = 0; i< num_sacks; i++) {
-                __u32 start_seq = ntohl(sp[i].start_seq);
-                __u32 end_seq =  ntohl(sp[i].end_seq);
+        for (i = 0; i < num_sacks; i++) {
+                __be32 start_seq = sp[i].start_seq;
+                __be32 end_seq = sp[i].end_seq;
 
-                if (i == 0){
+                if (i == 0) {
                         if (tp->recv_sack_cache[i].start_seq != start_seq)
                                 flag = 0;
                 } else {
@@ -970,37 +997,6 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                 }
                 tp->recv_sack_cache[i].start_seq = start_seq;
                 tp->recv_sack_cache[i].end_seq = end_seq;
-
-                /* Check for D-SACK. */
-                if (i == 0) {
-                        u32 ack = TCP_SKB_CB(ack_skb)->ack_seq;
-
-                        if (before(start_seq, ack)) {
-                                dup_sack = 1;
-                                tp->rx_opt.sack_ok |= 4;
-                                NET_INC_STATS_BH(LINUX_MIB_TCPDSACKRECV);
-                        } else if (num_sacks > 1 &&
-                                   !after(end_seq, ntohl(sp[1].end_seq)) &&
-                                   !before(start_seq, ntohl(sp[1].start_seq))) {
-                                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 &&
-                            !after(end_seq, prior_snd_una) &&
-                            after(end_seq, tp->undo_marker))
-                                tp->undo_retrans--;
-
-                        /* Eliminate too old ACKs, but take into
-                         * account more or less fresh ones, they can
-                         * contain valid SACK info.
-                         */
-                        if (before(ack, prior_snd_una - tp->max_window))
-                                return 0;
-                }
         }
 
         first_sack_index = 0;