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>

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index ca46eb9151f8e535f13756e48844b1580c5f0ca1..3c8e297e2c39c6f66b0d4ffb2e8d5b2c5b9d3b0c 100644 (file)
--- 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);
        }