1 files changed, 17 insertions, 28 deletions

diff --git a/net/ipv4/tcp_dctcp.c b/net/ipv4/tcp_dctcp.c
index 359da68d7c06..477cb4aa456c 100644
--- a/net/ipv4/tcp_dctcp.c
+++ b/net/ipv4/tcp_dctcp.c
@@ -49,9 +49,8 @@
 #define DCTCP_MAX_ALPHA 1024U
 
 struct dctcp {
-        u32 acked_bytes_ecn;
-        u32 acked_bytes_total;
-        u32 prior_snd_una;
+        u32 old_delivered;
+        u32 old_delivered_ce;
         u32 prior_rcv_nxt;
         u32 dctcp_alpha;
         u32 next_seq;
@@ -73,8 +72,8 @@ static void dctcp_reset(const struct tcp_sock *tp, struct dctcp *ca)
 {
         ca->next_seq = tp->snd_nxt;
 
-        ca->acked_bytes_ecn = 0;
-        ca->acked_bytes_total = 0;
+        ca->old_delivered = tp->delivered;
+        ca->old_delivered_ce = tp->delivered_ce;
 }
 
 static void dctcp_init(struct sock *sk)
@@ -86,7 +85,6 @@ static void dctcp_init(struct sock *sk)
              sk->sk_state == TCP_CLOSE)) {
                 struct dctcp *ca = inet_csk_ca(sk);
 
-                ca->prior_snd_una = tp->snd_una;
                 ca->prior_rcv_nxt = tp->rcv_nxt;
 
                 ca->dctcp_alpha = min(dctcp_alpha_on_init, DCTCP_MAX_ALPHA);
@@ -118,37 +116,25 @@ static void dctcp_update_alpha(struct sock *sk, u32 flags)
 {
         const struct tcp_sock *tp = tcp_sk(sk);
         struct dctcp *ca = inet_csk_ca(sk);
-        u32 acked_bytes = tp->snd_una - ca->prior_snd_una;
-
-        /* If ack did not advance snd_una, count dupack as MSS size.
-         * If ack did update window, do not count it at all.
-         */
-        if (acked_bytes == 0 && !(flags & CA_ACK_WIN_UPDATE))
-                acked_bytes = inet_csk(sk)->icsk_ack.rcv_mss;
-        if (acked_bytes) {
-                ca->acked_bytes_total += acked_bytes;
-                ca->prior_snd_una = tp->snd_una;
-
-                if (flags & CA_ACK_ECE)
-                        ca->acked_bytes_ecn += acked_bytes;
-        }
 
         /* Expired RTT */
         if (!before(tp->snd_una, ca->next_seq)) {
-                u64 bytes_ecn = ca->acked_bytes_ecn;
+                u32 delivered_ce = tp->delivered_ce - ca->old_delivered_ce;
                 u32 alpha = ca->dctcp_alpha;
 
                 /* alpha = (1 - g) * alpha + g * F */
 
                 alpha -= min_not_zero(alpha, alpha >> dctcp_shift_g);
-                if (bytes_ecn) {
+                if (delivered_ce) {
+                        u32 delivered = tp->delivered - ca->old_delivered;
+
                         /* If dctcp_shift_g == 1, a 32bit value would overflow
-                         * after 8 Mbytes.
+                         * after 8 M packets.
                          */
-                        bytes_ecn <<= (10 - dctcp_shift_g);
-                        do_div(bytes_ecn, max(1U, ca->acked_bytes_total));
+                        delivered_ce <<= (10 - dctcp_shift_g);
+                        delivered_ce /= max(1U, delivered);
 
-                        alpha = min(alpha + (u32)bytes_ecn, DCTCP_MAX_ALPHA);
+                        alpha = min(alpha + delivered_ce, DCTCP_MAX_ALPHA);
                 }
                 /* dctcp_alpha can be read from dctcp_get_info() without
                  * synchro, so we ask compiler to not use dctcp_alpha
@@ -200,6 +186,7 @@ static size_t dctcp_get_info(struct sock *sk, u32 ext, int *attr,
                              union tcp_cc_info *info)
 {
         const struct dctcp *ca = inet_csk_ca(sk);
+        const struct tcp_sock *tp = tcp_sk(sk);
 
         /* Fill it also in case of VEGASINFO due to req struct limits.
          * We can still correctly retrieve it later.
@@ -211,8 +198,10 @@ static size_t dctcp_get_info(struct sock *sk, u32 ext, int *attr,
                         info->dctcp.dctcp_enabled = 1;
                         info->dctcp.dctcp_ce_state = (u16) ca->ce_state;
                         info->dctcp.dctcp_alpha = ca->dctcp_alpha;
-                        info->dctcp.dctcp_ab_ecn = ca->acked_bytes_ecn;
-                        info->dctcp.dctcp_ab_tot = ca->acked_bytes_total;
+                        info->dctcp.dctcp_ab_ecn = tp->mss_cache *
+                                                   (tp->delivered_ce - ca->old_delivered_ce);
+                        info->dctcp.dctcp_ab_tot = tp->mss_cache *
+                                                   (tp->delivered - ca->old_delivered);
                 }
 
                 *attr = INET_DIAG_DCTCPINFO;