Commit 9e45a3e3 authored by Yuchung Cheng's avatar Yuchung Cheng Committed by David S. Miller

tcp: apply Kern's check on RTTs used for congestion control

Currently ca_seq_rtt_us does not use Kern's check. Fix that by
checking if any packet acked is a retransmit, for both RTT used
for RTT estimation and congestion control.

Fixes: 5b08e47c ("tcp: prefer packet timing to TS-ECR for RTT")
Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c8fdc324
......@@ -2925,9 +2925,6 @@ static inline bool tcp_ack_update_rtt(struct sock *sk, const int flag,
* Karn's algorithm forbids taking RTT if some retransmitted data
* is acked (RFC6298).
*/
if (flag & FLAG_RETRANS_DATA_ACKED)
seq_rtt_us = -1L;
if (seq_rtt_us < 0)
seq_rtt_us = sack_rtt_us;
......@@ -3169,7 +3166,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
flag |= FLAG_SACK_RENEGING;
skb_mstamp_get(&now);
if (likely(first_ackt.v64)) {
if (likely(first_ackt.v64) && !(flag & FLAG_RETRANS_DATA_ACKED)) {
seq_rtt_us = skb_mstamp_us_delta(&now, &first_ackt);
ca_rtt_us = skb_mstamp_us_delta(&now, &last_ackt);
}
......
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