tcp: introduce tcp_skb_timestamp_us() helper

There are few places where TCP reads skb->skb_mstamp expecting
a value in usec unit.

skb->tstamp (aka skb->skb_mstamp) will soon store CLOCK_TAI nsec value.

Add tcp_skb_timestamp_us() to provide proper conversion when needed.

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

1 files changed, 6 insertions, 5 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index d9034073138c..d703a0b3b6a2 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1305,7 +1305,7 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *prev,
          */
         tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,
                         start_seq, end_seq, dup_sack, pcount,
-                        skb->skb_mstamp);
+                        tcp_skb_timestamp_us(skb));
         tcp_rate_skb_delivered(sk, skb, state->rate);
 
         if (skb == tp->lost_skb_hint)
@@ -1580,7 +1580,7 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
                                                 TCP_SKB_CB(skb)->end_seq,
                                                 dup_sack,
                                                 tcp_skb_pcount(skb),
-                                                skb->skb_mstamp);
+                                                tcp_skb_timestamp_us(skb));
                         tcp_rate_skb_delivered(sk, skb, state->rate);
                         if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)
                                 list_del_init(&skb->tcp_tsorted_anchor);
@@ -3103,7 +3103,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack,
                                 tp->retrans_out -= acked_pcount;
                         flag |= FLAG_RETRANS_DATA_ACKED;
                 } else if (!(sacked & TCPCB_SACKED_ACKED)) {
-                        last_ackt = skb->skb_mstamp;
+                        last_ackt = tcp_skb_timestamp_us(skb);
                         WARN_ON_ONCE(last_ackt == 0);
                         if (!first_ackt)
                                 first_ackt = last_ackt;
@@ -3121,7 +3121,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack,
                         tp->delivered += acked_pcount;
                         if (!tcp_skb_spurious_retrans(tp, skb))
                                 tcp_rack_advance(tp, sacked, scb->end_seq,
-                                                 skb->skb_mstamp);
+                                                 tcp_skb_timestamp_us(skb));
                 }
                 if (sacked & TCPCB_LOST)
                         tp->lost_out -= acked_pcount;
@@ -3215,7 +3215,8 @@ static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack,
                         tp->lost_cnt_hint -= min(tp->lost_cnt_hint, delta);
                 }
         } else if (skb && rtt_update && sack_rtt_us >= 0 &&
-                   sack_rtt_us > tcp_stamp_us_delta(tp->tcp_mstamp, skb->skb_mstamp)) {
+                   sack_rtt_us > tcp_stamp_us_delta(tp->tcp_mstamp,
+                                                    tcp_skb_timestamp_us(skb))) {
                 /* Do not re-arm RTO if the sack RTT is measured from data sent
                  * after when the head was last (re)transmitted. Otherwise the
                  * timeout may continue to extend in loss recovery.