3 files changed, 4 insertions, 1 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 6939e69d3c37..5a1d26a18599 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -953,6 +953,7 @@ struct rate_sample {
         u32  prior_in_flight;   /* in flight before this ACK */
         bool is_app_limited;    /* is sample from packet with bubble in pipe? */
         bool is_retrans;        /* is sample from retransmission? */
+        bool is_ack_delayed;    /* is this (likely) a delayed ACK? */
 };
 
 struct tcp_congestion_ops {
diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c
index 8322f26e770e..785712be5b0d 100644
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -766,7 +766,8 @@ static void bbr_update_min_rtt(struct sock *sk, const struct rate_sample *rs)
         filter_expired = after(tcp_jiffies32,
                                bbr->min_rtt_stamp + bbr_min_rtt_win_sec * HZ);
         if (rs->rtt_us >= 0 &&
-            (rs->rtt_us <= bbr->min_rtt_us || filter_expired)) {
+            (rs->rtt_us <= bbr->min_rtt_us ||
+             (filter_expired && !rs->is_ack_delayed))) {
                 bbr->min_rtt_us = rs->rtt_us;
                 bbr->min_rtt_stamp = tcp_jiffies32;
         }
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2c6797134553..cfa51cfd2d99 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3633,6 +3633,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 
         delivered = tp->delivered - delivered;  /* freshly ACKed or SACKed */
         lost = tp->lost - lost;                 /* freshly marked lost */
+        rs.is_ack_delayed = !!(flag & FLAG_ACK_MAYBE_DELAYED);
         tcp_rate_gen(sk, delivered, lost, is_sack_reneg, sack_state.rate);
         tcp_cong_control(sk, ack, delivered, flag, sack_state.rate);
         tcp_xmit_recovery(sk, rexmit);