1 files changed, 15 insertions, 31 deletions

diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index 4f6c35261b6e..02d126d9a711 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -199,9 +199,8 @@ static void ccid2_hc_tx_rto_expire(unsigned long data)
         hctx->ccid2hctx_pipe     = 0;
 
         /* clear state about stuff we sent */
-        hctx->ccid2hctx_seqt    = hctx->ccid2hctx_seqh;
-        hctx->ccid2hctx_ssacks  = 0;
-        hctx->ccid2hctx_acks    = 0;
+        hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
+        hctx->ccid2hctx_packets_acked = 0;
 
         /* clear ack ratio state. */
         hctx->ccid2hctx_rpseq    = 0;
@@ -406,31 +405,15 @@ static inline void ccid2_new_ack(struct sock *sk,
 {
         struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
 
-        /* slow start */
         if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
-                hctx->ccid2hctx_acks = 0;
-
-                /* We can increase cwnd at most maxincr [ack_ratio/2] */
-                if (*maxincr) {
-                        /* increase every 2 acks */
-                        hctx->ccid2hctx_ssacks++;
-                        if (hctx->ccid2hctx_ssacks == 2) {
-                                hctx->ccid2hctx_cwnd++;
-                                hctx->ccid2hctx_ssacks = 0;
-                                *maxincr = *maxincr - 1;
-                        }
-                } else {
-                        /* increased cwnd enough for this single ack */
-                        hctx->ccid2hctx_ssacks = 0;
-                }
-        } else {
-                hctx->ccid2hctx_ssacks = 0;
-                hctx->ccid2hctx_acks++;
-
-                if (hctx->ccid2hctx_acks >= hctx->ccid2hctx_cwnd) {
-                        hctx->ccid2hctx_cwnd++;
-                        hctx->ccid2hctx_acks = 0;
+                if (*maxincr > 0 && ++hctx->ccid2hctx_packets_acked == 2) {
+                        hctx->ccid2hctx_cwnd += 1;
+                        *maxincr             -= 1;
+                        hctx->ccid2hctx_packets_acked = 0;
                 }
+        } else if (++hctx->ccid2hctx_packets_acked >= hctx->ccid2hctx_cwnd) {
+                        hctx->ccid2hctx_cwnd += 1;
+                        hctx->ccid2hctx_packets_acked = 0;
         }
 
         /* update RTO */
@@ -596,12 +579,13 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                 }
         }
 
-        /* If in slow-start, cwnd can increase at most Ack Ratio / 2 packets for
-         * this single ack.  I round up.
-         * -sorbo.
+        /*
+         * In slow-start, cwnd can increase up to a maximum of Ack Ratio/2
+         * packets per acknowledgement. Rounding up avoids that cwnd is not
+         * advanced when Ack Ratio is 1 and gives a slight edge otherwise.
          */
-        maxincr = dp->dccps_l_ack_ratio >> 1;
-        maxincr++;
+        if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh)
+                maxincr = DIV_ROUND_UP(dp->dccps_l_ack_ratio, 2);
 
         /* go through all ack vectors */
         while ((offset = ccid2_ackvector(sk, skb, offset,