[TCP] TCP Yeah: cleanup

Eliminate need for full 6/4/64 divide to compute queue.
Variable maxqueue was really a constant.
Fix indentation.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 19 deletions

diff --git a/net/ipv4/tcp_yeah.c b/net/ipv4/tcp_yeah.c
index 18355a2608e1..46dd1bee583a 100644
--- a/net/ipv4/tcp_yeah.c
+++ b/net/ipv4/tcp_yeah.c
@@ -74,7 +74,7 @@ static void tcp_yeah_pkts_acked(struct sock *sk, u32 pkts_acked)
 }
 
 static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
-                                 u32 seq_rtt, u32 in_flight, int flag)
+                                u32 seq_rtt, u32 in_flight, int flag)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         struct yeah *yeah = inet_csk_ca(sk);
@@ -142,8 +142,8 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
                  */
 
                 if (yeah->cntRTT > 2) {
-                        u32 rtt;
-                        u32 queue, maxqueue;
+                        u32 rtt, queue;
+                        u64 bw;
 
                         /* We have enough RTT samples, so, using the Vegas
                          * algorithm, we determine if we should increase or
@@ -158,32 +158,36 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
                          */
                         rtt = yeah->minRTT;
 
-                        queue = (u32)div64_64((u64)tp->snd_cwnd * (rtt - yeah->baseRTT), rtt);
-
-                        maxqueue = TCP_YEAH_ALPHA;
-
-                        if (queue > maxqueue ||
-                                    rtt - yeah->baseRTT > (yeah->baseRTT / TCP_YEAH_PHY)) {
-
-                                if (queue > maxqueue && tp->snd_cwnd > yeah->reno_count) {
-                                        u32 reduction = min( queue / TCP_YEAH_GAMMA ,
-                                                         tp->snd_cwnd >> TCP_YEAH_EPSILON );
+                        /* Compute excess number of packets above bandwidth
+                         * Avoid doing full 64 bit divide.
+                         */
+                        bw = tp->snd_cwnd;
+                        bw *= rtt - yeah->baseRTT;
+                        do_div(bw, rtt);
+                        queue = bw;
+
+                        if (queue > TCP_YEAH_ALPHA ||
+                            rtt - yeah->baseRTT > (yeah->baseRTT / TCP_YEAH_PHY)) {
+                                if (queue > TCP_YEAH_ALPHA
+                                    && tp->snd_cwnd > yeah->reno_count) {
+                                        u32 reduction = min(queue / TCP_YEAH_GAMMA ,
+                                                            tp->snd_cwnd >> TCP_YEAH_EPSILON);
 
                                         tp->snd_cwnd -= reduction;
 
-                                        tp->snd_cwnd = max( tp->snd_cwnd, yeah->reno_count);
+                                        tp->snd_cwnd = max(tp->snd_cwnd,
+                                                           yeah->reno_count);
 
                                         tp->snd_ssthresh = tp->snd_cwnd;
-                        }
+                                }
 
                                 if (yeah->reno_count <= 2)
-                                        yeah->reno_count = max( tp->snd_cwnd>>1, 2U);
+                                        yeah->reno_count = max(tp->snd_cwnd>>1, 2U);
                                 else
                                         yeah->reno_count++;
 
-                                yeah->doing_reno_now =
-                                                   min_t( u32, yeah->doing_reno_now + 1 , 0xffffff);
-
+                                yeah->doing_reno_now = min(yeah->doing_reno_now + 1,
+                                                           0xffffffU);
                         } else {
                                 yeah->fast_count++;