[TCP]: Convert highest_sack to sk_buff to allow direct access

It is going to replace the sack fastpath hint quite soon... :-)

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

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index bac17c59b24ef8a0c24d93d1fc7e041c6e0b571c..34acee662230c85f15b433127b6357c744d3c248 100644 (file)
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -332,8 +332,10 @@ struct tcp_sock {
 
        struct tcp_sack_block_wire recv_sack_cache[4];
 
-       u32     highest_sack;   /* Start seq of globally highest revd SACK
-                                * (validity guaranteed only if sacked_out > 0) */
+       struct sk_buff *highest_sack;   /* highest skb with SACK received
+                                        * (validity guaranteed only if
+                                        * sacked_out > 0)
+                                        */
 
        /* from STCP, retrans queue hinting */
        struct sk_buff* lost_skb_hint;

diff --git a/include/net/tcp.h b/include/net/tcp.h
index d893b4480769305c8427b4a14201500629248727..0ede804b16d4f4559cec5cebd6c254023b28ec33 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1312,6 +1312,16 @@ static inline int tcp_write_queue_empty(struct sock *sk)
        return skb_queue_empty(&sk->sk_write_queue);
 }
 
+/* Start sequence of the highest skb with SACKed bit, valid only if
+ * sacked > 0 or when the caller has ensured validity by itself.
+ */
+static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp)
+{
+       if (!tp->sacked_out)
+               return tp->snd_una;
+       return TCP_SKB_CB(tp->highest_sack)->seq;
+}
+
 /* /proc */
 enum tcp_seq_states {
        TCP_SEQ_STATE_LISTENING,

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index c0e8f2b1fa7e149585ab5b7240ab9bd96d3f44ab..31294b52ad42831a6d1948228f11c51d27897d92 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1245,7 +1245,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
        int num_sacks = (ptr[1] - TCPOLEN_SACK_BASE)>>3;
        int reord = tp->packets_out;
        int prior_fackets;
-       u32 highest_sack_end_seq = tp->lost_retrans_low;
+       u32 highest_sack_end_seq;
        int flag = 0;
        int found_dup_sack = 0;
        int cached_fack_count;
@@ -1256,7 +1256,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
        if (!tp->sacked_out) {
                if (WARN_ON(tp->fackets_out))
                        tp->fackets_out = 0;
-               tp->highest_sack = tp->snd_una;
+               tp->highest_sack = tcp_write_queue_head(sk);
        }
        prior_fackets = tp->fackets_out;
 
@@ -1483,10 +1483,9 @@ 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;
-                                       highest_sack_end_seq = TCP_SKB_CB(skb)->end_seq;
-                               }
+                               if (after(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp)))
+                                       tp->highest_sack = skb;
+
                        } else {
                                if (dup_sack && (sacked&TCPCB_RETRANS))
                                        reord = min(fack_count, reord);
@@ -1514,6 +1513,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                        flag &= ~FLAG_ONLY_ORIG_SACKED;
        }
 
+       highest_sack_end_seq = TCP_SKB_CB(tp->highest_sack)->end_seq;
        if (tcp_is_fack(tp) && tp->retrans_out &&
            after(highest_sack_end_seq, tp->lost_retrans_low) &&
            icsk->icsk_ca_state == TCP_CA_Recovery)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index f4c1eef89af0b3ac1e63ed91ecf3725a761d6949..ce506af5ce072b505dc4b71faaba80742fefbfb4 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -657,13 +657,15 @@ static void tcp_set_skb_tso_segs(struct sock *sk, struct sk_buff *skb, unsigned
  * tweak SACK fastpath hint too as it would overwrite all changes unless
  * hint is also changed.
  */
-static void tcp_adjust_fackets_out(struct tcp_sock *tp, struct sk_buff *skb,
+static void tcp_adjust_fackets_out(struct sock *sk, struct sk_buff *skb,
                                   int decr)
 {
+       struct tcp_sock *tp = tcp_sk(sk);
+
        if (!tp->sacked_out || tcp_is_reno(tp))
                return;
 
-       if (!before(tp->highest_sack, TCP_SKB_CB(skb)->seq))
+       if (!before(tcp_highest_sack_seq(tp), TCP_SKB_CB(skb)->seq))
                tp->fackets_out -= decr;
 
        /* cnt_hint is "off-by-one" compared with fackets_out (see sacktag) */
@@ -712,9 +714,8 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss
        TCP_SKB_CB(buff)->end_seq = TCP_SKB_CB(skb)->end_seq;
        TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(buff)->seq;
 
-       if (tcp_is_sack(tp) && tp->sacked_out &&
-           (TCP_SKB_CB(skb)->seq == tp->highest_sack))
-               tp->highest_sack = TCP_SKB_CB(buff)->seq;
+       if (tcp_is_sack(tp) && tp->sacked_out && (skb == tp->highest_sack))
+               tp->highest_sack = buff;
 
        /* PSH and FIN should only be set in the second packet. */
        flags = TCP_SKB_CB(skb)->flags;
@@ -772,7 +773,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss
                        tcp_dec_pcount_approx_int(&tp->sacked_out, diff);
                        tcp_verify_left_out(tp);
                }
-               tcp_adjust_fackets_out(tp, skb, diff);
+               tcp_adjust_fackets_out(sk, skb, diff);
        }
 
        /* Link BUFF into the send queue. */
@@ -1712,7 +1713,7 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m
                       tcp_skb_pcount(next_skb) != 1);
 
                if (WARN_ON(tcp_is_sack(tp) && tp->sacked_out &&
-                   (TCP_SKB_CB(next_skb)->seq == tp->highest_sack)))
+                   (next_skb == tp->highest_sack)))
                        return;
 
                /* Ok.  We will be able to collapse the packet. */
@@ -1747,7 +1748,7 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m
                if (tcp_is_reno(tp) && tp->sacked_out)
                        tcp_dec_pcount_approx(&tp->sacked_out, next_skb);
 
-               tcp_adjust_fackets_out(tp, next_skb, tcp_skb_pcount(next_skb));
+               tcp_adjust_fackets_out(sk, next_skb, tcp_skb_pcount(next_skb));
                tp->packets_out -= tcp_skb_pcount(next_skb);
 
                /* changed transmit queue under us so clear hints */
@@ -2028,7 +2029,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
                        break;
                tp->forward_skb_hint = skb;
 
-               if (after(TCP_SKB_CB(skb)->seq, tp->highest_sack))
+               if (after(TCP_SKB_CB(skb)->seq, tcp_highest_sack_seq(tp)))
                        break;
 
                if (tcp_packets_in_flight(tp) >= tp->snd_cwnd)