tcp: remove TCP_SKB_CB(skb)->when

After commit 740b0f1841f6 ("tcp: switch rtt estimations to usec resolution"),
we no longer need to maintain timestamps in two different fields.

TCP_SKB_CB(skb)->when can be removed, as same information sits in skb_mstamp.stamp_jiffies

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 4 deletions

diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index df90cd1ce37f..a339e7ba05a4 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -135,10 +135,9 @@ static bool retransmits_timed_out(struct sock *sk,
         if (!inet_csk(sk)->icsk_retransmits)
                 return false;
 
-        if (unlikely(!tcp_sk(sk)->retrans_stamp))
-                start_ts = TCP_SKB_CB(tcp_write_queue_head(sk))->when;
-        else
-                start_ts = tcp_sk(sk)->retrans_stamp;
+        start_ts = tcp_sk(sk)->retrans_stamp;
+        if (unlikely(!start_ts))
+                start_ts = tcp_skb_timestamp(tcp_write_queue_head(sk));
 
         if (likely(timeout == 0)) {
                 linear_backoff_thresh = ilog2(TCP_RTO_MAX/rto_base);