tcp_lp: cache tcp_time_stamp

tcp_time_stamp will become slightly more expensive soon,
cache its value.

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

1 files changed, 4 insertions, 3 deletions

diff --git a/net/ipv4/tcp_lp.c b/net/ipv4/tcp_lp.c
index d6fb6c067af4..ef3122abb373 100644
--- a/net/ipv4/tcp_lp.c
+++ b/net/ipv4/tcp_lp.c
@@ -264,18 +264,19 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         struct lp *lp = inet_csk_ca(sk);
+        u32 now = tcp_time_stamp;
         u32 delta;
 
         if (sample->rtt_us > 0)
                 tcp_lp_rtt_sample(sk, sample->rtt_us);
 
         /* calc inference */
-        delta = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
+        delta = now - tp->rx_opt.rcv_tsecr;
         if ((s32)delta > 0)
                 lp->inference = 3 * delta;
 
         /* test if within inference */
-        if (lp->last_drop && (tcp_time_stamp - lp->last_drop < lp->inference))
+        if (lp->last_drop && (now - lp->last_drop < lp->inference))
                 lp->flag |= LP_WITHIN_INF;
         else
                 lp->flag &= ~LP_WITHIN_INF;
@@ -312,7 +313,7 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample)
                 tp->snd_cwnd = max(tp->snd_cwnd >> 1U, 1U);
 
         /* record this drop time */
-        lp->last_drop = tcp_time_stamp;
+        lp->last_drop = now;
 }
 
 static struct tcp_congestion_ops tcp_lp __read_mostly = {