tcp: make tcp_sacktag_one able to handle partial skb too

This is preparatory work for SACK combiner patch which may
have to count TCP state changes for only a part of the skb
because it will intentionally avoids splitting skb to SACKed
and not sacked parts.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 15 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index ca46eb9151f8..3c8e297e2c39 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1289,7 +1289,8 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb,
 }
 
 static int tcp_sacktag_one(struct sk_buff *skb, struct sock *sk,
-                           int *reord, int dup_sack, int fack_count)
+                           int *reord, int dup_sack, int fack_count,
+                           u8 *sackedto, int pcount)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         u8 sacked = TCP_SKB_CB(skb)->sacked;
@@ -1314,10 +1315,9 @@ static int tcp_sacktag_one(struct sk_buff *skb, struct sock *sk,
                          * that retransmission is still in flight.
                          */
                         if (sacked & TCPCB_LOST) {
-                                TCP_SKB_CB(skb)->sacked &=
-                                        ~(TCPCB_LOST|TCPCB_SACKED_RETRANS);
-                                tp->lost_out -= tcp_skb_pcount(skb);
-                                tp->retrans_out -= tcp_skb_pcount(skb);
+                                *sackedto &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS);
+                                tp->lost_out -= pcount;
+                                tp->retrans_out -= pcount;
                         }
                 } else {
                         if (!(sacked & TCPCB_RETRANS)) {
@@ -1334,22 +1334,22 @@ static int tcp_sacktag_one(struct sk_buff *skb, struct sock *sk,
                         }
 
                         if (sacked & TCPCB_LOST) {
-                                TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
-                                tp->lost_out -= tcp_skb_pcount(skb);
+                                *sackedto &= ~TCPCB_LOST;
+                                tp->lost_out -= pcount;
                         }
                 }
 
-                TCP_SKB_CB(skb)->sacked |= TCPCB_SACKED_ACKED;
+                *sackedto |= TCPCB_SACKED_ACKED;
                 flag |= FLAG_DATA_SACKED;
-                tp->sacked_out += tcp_skb_pcount(skb);
+                tp->sacked_out += pcount;
 
-                fack_count += tcp_skb_pcount(skb);
+                fack_count += pcount;
 
                 /* Lost marker hint past SACKed? Tweak RFC3517 cnt */
                 if (!tcp_is_fack(tp) && (tp->lost_skb_hint != NULL) &&
                     before(TCP_SKB_CB(skb)->seq,
                            TCP_SKB_CB(tp->lost_skb_hint)->seq))
-                        tp->lost_cnt_hint += tcp_skb_pcount(skb);
+                        tp->lost_cnt_hint += pcount;
 
                 if (fack_count > tp->fackets_out)
                         tp->fackets_out = fack_count;
@@ -1362,9 +1362,9 @@ static int tcp_sacktag_one(struct sk_buff *skb, struct sock *sk,
          * frames and clear it. undo_retrans is decreased above, L|R frames
          * are accounted above as well.
          */
-        if (dup_sack && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS)) {
-                TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
-                tp->retrans_out -= tcp_skb_pcount(skb);
+        if (dup_sack && (*sackedto & TCPCB_SACKED_RETRANS)) {
+                *sackedto &= ~TCPCB_SACKED_RETRANS;
+                tp->retrans_out -= pcount;
         }
 
         return flag;
@@ -1404,7 +1404,9 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
 
                 if (in_sack)
                         *flag |= tcp_sacktag_one(skb, sk, reord, dup_sack,
-                                                 *fack_count);
+                                                 *fack_count,
+                                                 &(TCP_SKB_CB(skb)->sacked),
+                                                 tcp_skb_pcount(skb));
 
                 *fack_count += tcp_skb_pcount(skb);
         }