1 files changed, 194 insertions, 94 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3e98b57578dc..40a26b7157b4 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -42,7 +42,7 @@
  *              Andi Kleen      :       Moved open_request checking here
  *                                      and process RSTs for open_requests.
  *              Andi Kleen      :       Better prune_queue, and other fixes.
- *              Andrey Savochkin:       Fix RTT measurements in the presnce of
+ *              Andrey Savochkin:       Fix RTT measurements in the presence of
  *                                      timestamps.
  *              Andrey Savochkin:       Check sequence numbers correctly when
  *                                      removing SACKs due to in sequence incoming
@@ -89,6 +89,7 @@ int sysctl_tcp_frto;
 int sysctl_tcp_nometrics_save;
 
 int sysctl_tcp_moderate_rcvbuf = 1;
+int sysctl_tcp_abc = 1;
 
 #define FLAG_DATA               0x01 /* Incoming frame contained data.          */
 #define FLAG_WIN_UPDATE         0x02 /* Incoming ACK was a window update.       */
@@ -223,7 +224,7 @@ static void tcp_fixup_sndbuf(struct sock *sk)
  *   of receiver window. Check #2.
  *
  * The scheme does not work when sender sends good segments opening
- * window and then starts to feed us spagetti. But it should work
+ * window and then starts to feed us spaghetti. But it should work
  * in common situations. Otherwise, we have to rely on queue collapsing.
  */
 
@@ -233,7 +234,7 @@ static int __tcp_grow_window(const struct sock *sk, struct tcp_sock *tp,
 {
         /* Optimize this! */
         int truesize = tcp_win_from_space(skb->truesize)/2;
-        int window = tcp_full_space(sk)/2;
+        int window = tcp_win_from_space(sysctl_tcp_rmem[2])/2;
 
         while (tp->rcv_ssthresh <= window) {
                 if (truesize <= skb->len)
@@ -277,7 +278,7 @@ static void tcp_fixup_rcvbuf(struct sock *sk)
         int rcvmem = tp->advmss + MAX_TCP_HEADER + 16 + sizeof(struct sk_buff);
 
         /* Try to select rcvbuf so that 4 mss-sized segments
-         * will fit to window and correspoding skbs will fit to our rcvbuf.
+         * will fit to window and corresponding skbs will fit to our rcvbuf.
          * (was 3; 4 is minimum to allow fast retransmit to work.)
          */
         while (tcp_win_from_space(rcvmem) < tp->advmss)
@@ -286,7 +287,7 @@ static void tcp_fixup_rcvbuf(struct sock *sk)
                 sk->sk_rcvbuf = min(4 * rcvmem, sysctl_tcp_rmem[2]);
 }
 
-/* 4. Try to fixup all. It is made iimediately after connection enters
+/* 4. Try to fixup all. It is made immediately after connection enters
  *    established state.
  */
 static void tcp_init_buffer_space(struct sock *sk)
@@ -326,37 +327,18 @@ static void tcp_init_buffer_space(struct sock *sk)
 static void tcp_clamp_window(struct sock *sk, struct tcp_sock *tp)
 {
         struct inet_connection_sock *icsk = inet_csk(sk);
-        struct sk_buff *skb;
-        unsigned int app_win = tp->rcv_nxt - tp->copied_seq;
-        int ofo_win = 0;
 
         icsk->icsk_ack.quick = 0;
 
-        skb_queue_walk(&tp->out_of_order_queue, skb) {
-                ofo_win += skb->len;
-        }
-
-        /* If overcommit is due to out of order segments,
-         * do not clamp window. Try to expand rcvbuf instead.
-         */
-        if (ofo_win) {
-                if (sk->sk_rcvbuf < sysctl_tcp_rmem[2] &&
-                    !(sk->sk_userlocks & SOCK_RCVBUF_LOCK) &&
-                    !tcp_memory_pressure &&
-                    atomic_read(&tcp_memory_allocated) < sysctl_tcp_mem[0])
-                        sk->sk_rcvbuf = min(atomic_read(&sk->sk_rmem_alloc),
-                                            sysctl_tcp_rmem[2]);
+        if (sk->sk_rcvbuf < sysctl_tcp_rmem[2] &&
+            !(sk->sk_userlocks & SOCK_RCVBUF_LOCK) &&
+            !tcp_memory_pressure &&
+            atomic_read(&tcp_memory_allocated) < sysctl_tcp_mem[0]) {
+                sk->sk_rcvbuf = min(atomic_read(&sk->sk_rmem_alloc),
+                                    sysctl_tcp_rmem[2]);
         }
-        if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) {
-                app_win += ofo_win;
-                if (atomic_read(&sk->sk_rmem_alloc) >= 2 * sk->sk_rcvbuf)
-                        app_win >>= 1;
-                if (app_win > icsk->icsk_ack.rcv_mss)
-                        app_win -= icsk->icsk_ack.rcv_mss;
-                app_win = max(app_win, 2U*tp->advmss);
-
+        if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
                 tp->rcv_ssthresh = min(tp->window_clamp, 2U*tp->advmss);
-        }
 }
 
 /* Receiver "autotuning" code.
@@ -385,8 +367,8 @@ static void tcp_rcv_rtt_update(struct tcp_sock *tp, u32 sample, int win_dep)
                  * are stalled on filesystem I/O.
                  *
                  * Also, since we are only going for a minimum in the
-                 * non-timestamp case, we do not smoothe things out
-                 * else with timestamps disabled convergance takes too
+                 * non-timestamp case, we do not smoother things out
+                 * else with timestamps disabled convergence takes too
                  * long.
                  */
                 if (!win_dep) {
@@ -395,7 +377,7 @@ static void tcp_rcv_rtt_update(struct tcp_sock *tp, u32 sample, int win_dep)
                 } else if (m < new_sample)
                         new_sample = m << 3;
         } else {
-                /* No previous mesaure. */
+                /* No previous measure. */
                 new_sample = m << 3;
         }
 
@@ -524,7 +506,7 @@ static void tcp_event_data_recv(struct sock *sk, struct tcp_sock *tp, struct sk_
                         if (icsk->icsk_ack.ato > icsk->icsk_rto)
                                 icsk->icsk_ack.ato = icsk->icsk_rto;
                 } else if (m > icsk->icsk_rto) {
-                        /* Too long gap. Apparently sender falled to
+                        /* Too long gap. Apparently sender failed to
                          * restart window, so that we send ACKs quickly.
                          */
                         tcp_incr_quickack(sk);
@@ -548,10 +530,9 @@ static void tcp_event_data_recv(struct sock *sk, struct tcp_sock *tp, struct sk_
  * To save cycles in the RFC 1323 implementation it was better to break
  * it up into three procedures. -- erics
  */
-static void tcp_rtt_estimator(struct sock *sk, const __u32 mrtt, u32 *usrtt)
+static void tcp_rtt_estimator(struct sock *sk, const __u32 mrtt)
 {
         struct tcp_sock *tp = tcp_sk(sk);
-        const struct inet_connection_sock *icsk = inet_csk(sk);
         long m = mrtt; /* RTT */
 
         /*      The following amusing code comes from Jacobson's
@@ -565,7 +546,7 @@ static void tcp_rtt_estimator(struct sock *sk, const __u32 mrtt, u32 *usrtt)
          *
          * Funny. This algorithm seems to be very broken.
          * These formulae increase RTO, when it should be decreased, increase
-         * too slowly, when it should be incresed fastly, decrease too fastly
+         * too slowly, when it should be increased fastly, decrease too fastly
          * etc. I guess in BSD RTO takes ONE value, so that it is absolutely
          * does not matter how to _calculate_ it. Seems, it was trap
          * that VJ failed to avoid. 8)
@@ -610,9 +591,6 @@ static void tcp_rtt_estimator(struct sock *sk, const __u32 mrtt, u32 *usrtt)
                 tp->mdev_max = tp->rttvar = max(tp->mdev, TCP_RTO_MIN);
                 tp->rtt_seq = tp->snd_nxt;
         }
-
-        if (icsk->icsk_ca_ops->rtt_sample)
-                icsk->icsk_ca_ops->rtt_sample(sk, *usrtt);
 }
 
 /* Calculate rto without backoff.  This is the second half of Van Jacobson's
@@ -629,14 +607,14 @@ static inline void tcp_set_rto(struct sock *sk)
          *    at least by solaris and freebsd. "Erratic ACKs" has _nothing_
          *    to do with delayed acks, because at cwnd>2 true delack timeout
          *    is invisible. Actually, Linux-2.4 also generates erratic
-         *    ACKs in some curcumstances.
+         *    ACKs in some circumstances.
          */
         inet_csk(sk)->icsk_rto = (tp->srtt >> 3) + tp->rttvar;
 
         /* 2. Fixups made earlier cannot be right.
          *    If we do not estimate RTO correctly without them,
          *    all the algo is pure shit and should be replaced
-         *    with correct one. It is exaclty, which we pretend to do.
+         *    with correct one. It is exactly, which we pretend to do.
          */
 }
 
@@ -794,7 +772,7 @@ static void tcp_init_metrics(struct sock *sk)
          * to make it more realistic.
          *
          * A bit of theory. RTT is time passed after "normal" sized packet
-         * is sent until it is ACKed. In normal curcumstances sending small
+         * is sent until it is ACKed. In normal circumstances sending small
          * packets force peer to delay ACKs and calculation is correct too.
          * The algorithm is adaptive and, provided we follow specs, it
          * NEVER underestimate RTT. BUT! If peer tries to make some clever
@@ -919,18 +897,32 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
         int prior_fackets;
         u32 lost_retrans = 0;
         int flag = 0;
+        int dup_sack = 0;
         int i;
 
         if (!tp->sacked_out)
                 tp->fackets_out = 0;
         prior_fackets = tp->fackets_out;
 
-        for (i=0; i<num_sacks; i++, sp++) {
-                struct sk_buff *skb;
-                __u32 start_seq = ntohl(sp->start_seq);
-                __u32 end_seq = ntohl(sp->end_seq);
-                int fack_count = 0;
-                int dup_sack = 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);
+
+                if (i == 0){
+                        if (tp->recv_sack_cache[i].start_seq != start_seq)
+                                flag = 0;
+                } else {
+                        if ((tp->recv_sack_cache[i].start_seq != start_seq) ||
+                            (tp->recv_sack_cache[i].end_seq != end_seq))
+                                flag = 0;
+                }
+                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) {
@@ -962,15 +954,58 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                         if (before(ack, prior_snd_una - tp->max_window))
                                 return 0;
                 }
+        }
+
+        if (flag)
+                num_sacks = 1;
+        else {
+                int j;
+                tp->fastpath_skb_hint = NULL;
+
+                /* order SACK blocks to allow in order walk of the retrans queue */
+                for (i = num_sacks-1; i > 0; i--) {
+                        for (j = 0; j < i; j++){
+                                if (after(ntohl(sp[j].start_seq),
+                                          ntohl(sp[j+1].start_seq))){
+                                        sp[j].start_seq = htonl(tp->recv_sack_cache[j+1].start_seq);
+                                        sp[j].end_seq = htonl(tp->recv_sack_cache[j+1].end_seq);
+                                        sp[j+1].start_seq = htonl(tp->recv_sack_cache[j].start_seq);
+                                        sp[j+1].end_seq = htonl(tp->recv_sack_cache[j].end_seq);
+                                }
+
+                        }
+                }
+        }
+
+        /* clear flag as used for different purpose in following code */
+        flag = 0;
+
+        for (i=0; i<num_sacks; i++, sp++) {
+                struct sk_buff *skb;
+                __u32 start_seq = ntohl(sp->start_seq);
+                __u32 end_seq = ntohl(sp->end_seq);
+                int fack_count;
+
+                /* Use SACK fastpath hint if valid */
+                if (tp->fastpath_skb_hint) {
+                        skb = tp->fastpath_skb_hint;
+                        fack_count = tp->fastpath_cnt_hint;
+                } else {
+                        skb = sk->sk_write_queue.next;
+                        fack_count = 0;
+                }
 
                 /* Event "B" in the comment above. */
                 if (after(end_seq, tp->high_seq))
                         flag |= FLAG_DATA_LOST;
 
-                sk_stream_for_retrans_queue(skb, sk) {
+                sk_stream_for_retrans_queue_from(skb, sk) {
                         int in_sack, pcount;
                         u8 sacked;
 
+                        tp->fastpath_skb_hint = skb;
+                        tp->fastpath_cnt_hint = fack_count;
+
                         /* The retransmission queue is always in order, so
                          * we can short-circuit the walk early.
                          */
@@ -1045,6 +1080,9 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                                                 TCP_SKB_CB(skb)->sacked &= ~(TCPCB_LOST|TCPCB_SACKED_RETRANS);
                                                 tp->lost_out -= tcp_skb_pcount(skb);
                                                 tp->retrans_out -= tcp_skb_pcount(skb);
+
+                                                /* clear lost hint */
+                                                tp->retransmit_skb_hint = NULL;
                                         }
                                 } else {
                                         /* New sack for not retransmitted frame,
@@ -1057,6 +1095,9 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                                         if (sacked & TCPCB_LOST) {
                                                 TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
                                                 tp->lost_out -= tcp_skb_pcount(skb);
+
+                                                /* clear lost hint */
+                                                tp->retransmit_skb_hint = NULL;
                                         }
                                 }
 
@@ -1080,6 +1121,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                             (TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_RETRANS)) {
                                 TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
                                 tp->retrans_out -= tcp_skb_pcount(skb);
+                                tp->retransmit_skb_hint = NULL;
                         }
                 }
         }
@@ -1107,6 +1149,9 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                                 TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
                                 tp->retrans_out -= tcp_skb_pcount(skb);
 
+                                /* clear lost hint */
+                                tp->retransmit_skb_hint = NULL;
+
                                 if (!(TCP_SKB_CB(skb)->sacked&(TCPCB_LOST|TCPCB_SACKED_ACKED))) {
                                         tp->lost_out += tcp_skb_pcount(skb);
                                         TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
@@ -1214,6 +1259,8 @@ static void tcp_enter_frto_loss(struct sock *sk)
         tcp_set_ca_state(sk, TCP_CA_Loss);
         tp->high_seq = tp->frto_highmark;
         TCP_ECN_queue_cwr(tp);
+
+        clear_all_retrans_hints(tp);
 }
 
 void tcp_clear_retrans(struct tcp_sock *tp)
@@ -1251,6 +1298,7 @@ void tcp_enter_loss(struct sock *sk, int how)
         tp->snd_cwnd_cnt   = 0;
         tp->snd_cwnd_stamp = tcp_time_stamp;
 
+        tp->bytes_acked = 0;
         tcp_clear_retrans(tp);
 
         /* Push undo marker, if it was plain RTO and nothing
@@ -1279,6 +1327,8 @@ void tcp_enter_loss(struct sock *sk, int how)
         tcp_set_ca_state(sk, TCP_CA_Loss);
         tp->high_seq = tp->snd_nxt;
         TCP_ECN_queue_cwr(tp);
+
+        clear_all_retrans_hints(tp);
 }
 
 static int tcp_check_sack_reneging(struct sock *sk)
@@ -1503,17 +1553,37 @@ static void tcp_mark_head_lost(struct sock *sk, struct tcp_sock *tp,
                                int packets, u32 high_seq)
 {
         struct sk_buff *skb;
-        int cnt = packets;
+        int cnt;
 
-        BUG_TRAP(cnt <= tp->packets_out);
+        BUG_TRAP(packets <= tp->packets_out);
+        if (tp->lost_skb_hint) {
+                skb = tp->lost_skb_hint;
+                cnt = tp->lost_cnt_hint;
+        } else {
+                skb = sk->sk_write_queue.next;
+                cnt = 0;
+        }
 
-        sk_stream_for_retrans_queue(skb, sk) {
-                cnt -= tcp_skb_pcount(skb);
-                if (cnt < 0 || after(TCP_SKB_CB(skb)->end_seq, high_seq))
+        sk_stream_for_retrans_queue_from(skb, sk) {
+                /* TODO: do this better */
+                /* this is not the most efficient way to do this... */
+                tp->lost_skb_hint = skb;
+                tp->lost_cnt_hint = cnt;
+                cnt += tcp_skb_pcount(skb);
+                if (cnt > packets || after(TCP_SKB_CB(skb)->end_seq, high_seq))
                         break;
                 if (!(TCP_SKB_CB(skb)->sacked&TCPCB_TAGBITS)) {
                         TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
                         tp->lost_out += tcp_skb_pcount(skb);
+
+                        /* clear xmit_retransmit_queue hints
+                         *  if this is beyond hint */
+                        if(tp->retransmit_skb_hint != NULL &&
+                           before(TCP_SKB_CB(skb)->seq,
+                                  TCP_SKB_CB(tp->retransmit_skb_hint)->seq)) {
+
+                                tp->retransmit_skb_hint = NULL;
+                        }
                 }
         }
         tcp_sync_left_out(tp);
@@ -1540,13 +1610,28 @@ static void tcp_update_scoreboard(struct sock *sk, struct tcp_sock *tp)
         if (tcp_head_timedout(sk, tp)) {
                 struct sk_buff *skb;
 
-                sk_stream_for_retrans_queue(skb, sk) {
-                        if (tcp_skb_timedout(sk, skb) &&
-                            !(TCP_SKB_CB(skb)->sacked&TCPCB_TAGBITS)) {
+                skb = tp->scoreboard_skb_hint ? tp->scoreboard_skb_hint
+                        : sk->sk_write_queue.next;
+
+                sk_stream_for_retrans_queue_from(skb, sk) {
+                        if (!tcp_skb_timedout(sk, skb))
+                                break;
+
+                        if (!(TCP_SKB_CB(skb)->sacked&TCPCB_TAGBITS)) {
                                 TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
                                 tp->lost_out += tcp_skb_pcount(skb);
+
+                                /* clear xmit_retrans hint */
+                                if (tp->retransmit_skb_hint &&
+                                    before(TCP_SKB_CB(skb)->seq,
+                                           TCP_SKB_CB(tp->retransmit_skb_hint)->seq))
+
+                                        tp->retransmit_skb_hint = NULL;
                         }
                 }
+
+                tp->scoreboard_skb_hint = skb;
+
                 tcp_sync_left_out(tp);
         }
 }
@@ -1626,6 +1711,10 @@ static void tcp_undo_cwr(struct sock *sk, const int undo)
         }
         tcp_moderate_cwnd(tp);
         tp->snd_cwnd_stamp = tcp_time_stamp;
+
+        /* There is something screwy going on with the retrans hints after
+           an undo */
+        clear_all_retrans_hints(tp);
 }
 
 static inline int tcp_may_undo(struct tcp_sock *tp)
@@ -1709,6 +1798,9 @@ static int tcp_try_undo_loss(struct sock *sk, struct tcp_sock *tp)
                 sk_stream_for_retrans_queue(skb, sk) {
                         TCP_SKB_CB(skb)->sacked &= ~TCPCB_LOST;
                 }
+
+                clear_all_retrans_hints(tp);
+
                 DBGUNDO(sk, tp, "partial loss");
                 tp->lost_out = 0;
                 tp->left_out = tp->sacked_out;
@@ -1908,6 +2000,7 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
                         TCP_ECN_queue_cwr(tp);
                 }
 
+                tp->bytes_acked = 0;
                 tp->snd_cwnd_cnt = 0;
                 tcp_set_ca_state(sk, TCP_CA_Recovery);
         }
@@ -1919,9 +2012,9 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
 }
 
 /* Read draft-ietf-tcplw-high-performance before mucking
- * with this code. (Superceeds RFC1323)
+ * with this code. (Supersedes RFC1323)
  */
-static void tcp_ack_saw_tstamp(struct sock *sk, u32 *usrtt, int flag)
+static void tcp_ack_saw_tstamp(struct sock *sk, int flag)
 {
         /* RTTM Rule: A TSecr value received in a segment is used to
          * update the averaged RTT measurement only if the segment
@@ -1932,7 +2025,7 @@ static void tcp_ack_saw_tstamp(struct sock *sk, u32 *usrtt, int flag)
          * 1998/04/10 Andrey V. Savochkin <saw@msu.ru>
          *
          * Changed: reset backoff as soon as we see the first valid sample.
-         * If we do not, we get strongly overstimated rto. With timestamps
+         * If we do not, we get strongly overestimated rto. With timestamps
          * samples are accepted even from very old segments: f.e., when rtt=1
          * increases to 8, we retransmit 5 times and after 8 seconds delayed
          * answer arrives rto becomes 120 seconds! If at least one of segments
@@ -1940,13 +2033,13 @@ static void tcp_ack_saw_tstamp(struct sock *sk, u32 *usrtt, int flag)
          */
         struct tcp_sock *tp = tcp_sk(sk);
         const __u32 seq_rtt = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
-        tcp_rtt_estimator(sk, seq_rtt, usrtt);
+        tcp_rtt_estimator(sk, seq_rtt);
         tcp_set_rto(sk);
         inet_csk(sk)->icsk_backoff = 0;
         tcp_bound_rto(sk);
 }
 
-static void tcp_ack_no_tstamp(struct sock *sk, u32 seq_rtt, u32 *usrtt, int flag)
+static void tcp_ack_no_tstamp(struct sock *sk, u32 seq_rtt, int flag)
 {
         /* We don't have a timestamp. Can only use
          * packets that are not retransmitted to determine
@@ -1960,21 +2053,21 @@ static void tcp_ack_no_tstamp(struct sock *sk, u32 seq_rtt, u32 *usrtt, int flag
         if (flag & FLAG_RETRANS_DATA_ACKED)
                 return;
 
-        tcp_rtt_estimator(sk, seq_rtt, usrtt);
+        tcp_rtt_estimator(sk, seq_rtt);
         tcp_set_rto(sk);
         inet_csk(sk)->icsk_backoff = 0;
         tcp_bound_rto(sk);
 }
 
 static inline void tcp_ack_update_rtt(struct sock *sk, const int flag,
-                                      const s32 seq_rtt, u32 *usrtt)
+                                      const s32 seq_rtt)
 {
         const struct tcp_sock *tp = tcp_sk(sk);
         /* Note that peer MAY send zero echo. In this case it is ignored. (rfc1323) */
         if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
-                tcp_ack_saw_tstamp(sk, usrtt, flag);
+                tcp_ack_saw_tstamp(sk, flag);
         else if (seq_rtt >= 0)
-                tcp_ack_no_tstamp(sk, seq_rtt, usrtt, flag);
+                tcp_ack_no_tstamp(sk, seq_rtt, flag);
 }
 
 static inline void tcp_cong_avoid(struct sock *sk, u32 ack, u32 rtt,
@@ -2054,20 +2147,27 @@ static int tcp_tso_acked(struct sock *sk, struct sk_buff *skb,
         return acked;
 }
 
+static inline u32 tcp_usrtt(const struct sk_buff *skb)
+{
+        struct timeval tv, now;
+
+        do_gettimeofday(&now);
+        skb_get_timestamp(skb, &tv);
+        return (now.tv_sec - tv.tv_sec) * 1000000 + (now.tv_usec - tv.tv_usec);
+}
 
 /* Remove acknowledged frames from the retransmission queue. */
-static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p, s32 *seq_usrtt)
+static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
 {
         struct tcp_sock *tp = tcp_sk(sk);
+        const struct inet_connection_sock *icsk = inet_csk(sk);
         struct sk_buff *skb;
         __u32 now = tcp_time_stamp;
         int acked = 0;
         __s32 seq_rtt = -1;
-        struct timeval usnow;
         u32 pkts_acked = 0;
-
-        if (seq_usrtt)
-                do_gettimeofday(&usnow);
+        void (*rtt_sample)(struct sock *sk, u32 usrtt)
+                = icsk->icsk_ca_ops->rtt_sample;
 
         while ((skb = skb_peek(&sk->sk_write_queue)) &&
                skb != sk->sk_send_head) {
@@ -2107,16 +2207,11 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p, s32 *seq_usrtt
                                         tp->retrans_out -= tcp_skb_pcount(skb);
                                 acked |= FLAG_RETRANS_DATA_ACKED;
                                 seq_rtt = -1;
-                        } else if (seq_rtt < 0)
+                        } else if (seq_rtt < 0) {
                                 seq_rtt = now - scb->when;
-                        if (seq_usrtt) {
-                                struct timeval tv;
-                        
-                                skb_get_timestamp(skb, &tv);
-                                *seq_usrtt = (usnow.tv_sec - tv.tv_sec) * 1000000
-                                        + (usnow.tv_usec - tv.tv_usec);
+                                if (rtt_sample)
+                                        (*rtt_sample)(sk, tcp_usrtt(skb));
                         }
-
                         if (sacked & TCPCB_SACKED_ACKED)
                                 tp->sacked_out -= tcp_skb_pcount(skb);
                         if (sacked & TCPCB_LOST)
@@ -2126,17 +2221,20 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p, s32 *seq_usrtt
                                     !before(scb->end_seq, tp->snd_up))
                                         tp->urg_mode = 0;
                         }
-                } else if (seq_rtt < 0)
+                } else if (seq_rtt < 0) {
                         seq_rtt = now - scb->when;
+                        if (rtt_sample)
+                                (*rtt_sample)(sk, tcp_usrtt(skb));
+                }
                 tcp_dec_pcount_approx(&tp->fackets_out, skb);
                 tcp_packets_out_dec(tp, skb);
                 __skb_unlink(skb, &sk->sk_write_queue);
                 sk_stream_free_skb(sk, skb);
+                clear_all_retrans_hints(tp);
         }
 
         if (acked&FLAG_ACKED) {
-                const struct inet_connection_sock *icsk = inet_csk(sk);
-                tcp_ack_update_rtt(sk, acked, seq_rtt, seq_usrtt);
+                tcp_ack_update_rtt(sk, acked, seq_rtt);
                 tcp_ack_packets_out(sk, tp);
 
                 if (icsk->icsk_ca_ops->pkts_acked)
@@ -2284,7 +2382,7 @@ static void tcp_process_frto(struct sock *sk, u32 prior_snd_una)
         }
 
         /* F-RTO affects on two new ACKs following RTO.
-         * At latest on third ACK the TCP behavor is back to normal.
+         * At latest on third ACK the TCP behavior is back to normal.
          */
         tp->frto_counter = (tp->frto_counter + 1) % 3;
 }
@@ -2299,7 +2397,6 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
         u32 ack = TCP_SKB_CB(skb)->ack_seq;
         u32 prior_in_flight;
         s32 seq_rtt;
-        s32 seq_usrtt = 0;
         int prior_packets;
 
         /* If the ack is newer than sent or older than previous acks
@@ -2311,6 +2408,9 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
         if (before(ack, prior_snd_una))
                 goto old_ack;
 
+        if (sysctl_tcp_abc && icsk->icsk_ca_state < TCP_CA_CWR)
+                tp->bytes_acked += ack - prior_snd_una;
+
         if (!(flag&FLAG_SLOWPATH) && after(ack, prior_snd_una)) {
                 /* Window is constant, pure forward advance.
                  * No more checks are required.
@@ -2352,14 +2452,13 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
         prior_in_flight = tcp_packets_in_flight(tp);
 
         /* See if we can take anything off of the retransmit queue. */
-        flag |= tcp_clean_rtx_queue(sk, &seq_rtt,
-                                    icsk->icsk_ca_ops->rtt_sample ? &seq_usrtt : NULL);
+        flag |= tcp_clean_rtx_queue(sk, &seq_rtt);
 
         if (tp->frto_counter)
                 tcp_process_frto(sk, prior_snd_una);
 
         if (tcp_ack_is_dubious(sk, flag)) {
-                /* Advanve CWND, if state allows this. */
+                /* Advance CWND, if state allows this. */
                 if ((flag & FLAG_DATA_ACKED) && tcp_may_raise_cwnd(sk, flag))
                         tcp_cong_avoid(sk, ack,  seq_rtt, prior_in_flight, 0);
                 tcp_fastretrans_alert(sk, prior_snd_una, prior_packets, flag);
@@ -3148,7 +3247,7 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list,
 {
         struct sk_buff *skb;
 
-        /* First, check that queue is collapsable and find
+        /* First, check that queue is collapsible and find
          * the point where collapsing can be useful. */
         for (skb = head; skb != tail; ) {
                 /* No new bits? It is possible on ofo queue. */
@@ -3456,7 +3555,7 @@ static __inline__ void tcp_ack_snd_check(struct sock *sk)
 
 /*
  *      This routine is only called when we have urgent data
- *      signalled. Its the 'slow' part of tcp_urg. It could be
+ *      signaled. Its the 'slow' part of tcp_urg. It could be
  *      moved inline now as tcp_urg is only called from one
  *      place. We handle URGent data wrong. We have to - as
  *      BSD still doesn't use the correction from RFC961.
@@ -3501,7 +3600,7 @@ static void tcp_check_urg(struct sock * sk, struct tcphdr * th)
          * urgent. To do this requires some care. We cannot just ignore
          * tp->copied_seq since we would read the last urgent byte again
          * as data, nor can we alter copied_seq until this data arrives
-         * or we break the sematics of SIOCATMARK (and thus sockatmark())
+         * or we break the semantics of SIOCATMARK (and thus sockatmark())
          *
          * NOTE. Double Dutch. Rendering to plain English: author of comment
          * above did something sort of  send("A", MSG_OOB); send("B", MSG_OOB);
@@ -3646,7 +3745,7 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
         tp->rx_opt.saw_tstamp = 0;
 
         /*      pred_flags is 0xS?10 << 16 + snd_wnd
-         *      if header_predition is to be made
+         *      if header_prediction is to be made
          *      'S' will always be tp->tcp_header_len >> 2
          *      '?' will be 0 for the fast path, otherwise pred_flags is 0 to
          *  turn it off (when there are holes in the receive 
@@ -4242,7 +4341,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                                  */
                                 if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr &&
                                     !tp->srtt)
-                                        tcp_ack_saw_tstamp(sk, NULL, 0);
+                                        tcp_ack_saw_tstamp(sk, 0);
 
                                 if (tp->rx_opt.tstamp_ok)
                                         tp->advmss -= TCPOLEN_TSTAMP_ALIGNED;
@@ -4372,6 +4471,7 @@ discard:
 
 EXPORT_SYMBOL(sysctl_tcp_ecn);
 EXPORT_SYMBOL(sysctl_tcp_reordering);
+EXPORT_SYMBOL(sysctl_tcp_abc);
 EXPORT_SYMBOL(tcp_parse_options);
 EXPORT_SYMBOL(tcp_rcv_established);
 EXPORT_SYMBOL(tcp_rcv_state_process);