tcp: Refactor pingpong code

Instead of using pingpong as a single bit information, we refactor the
code to treat it as a counter. When interactive session is detected,
we set pingpong count to TCP_PINGPONG_THRESH. And when pingpong count
is >= TCP_PINGPONG_THRESH, we consider the session in pingpong mode.

This patch is a pure refactor and sets foundation for the next patch.
This patch itself does not change any pingpong logic.

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

1 files changed, 2 insertions, 2 deletions

diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index d7399a89469d..f0c86398e6a7 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -277,14 +277,14 @@ void tcp_delack_timer_handler(struct sock *sk)
         icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
 
         if (inet_csk_ack_scheduled(sk)) {
-                if (!icsk->icsk_ack.pingpong) {
+                if (!inet_csk_in_pingpong_mode(sk)) {
                         /* Delayed ACK missed: inflate ATO. */
                         icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1, icsk->icsk_rto);
                 } else {
                         /* Delayed ACK missed: leave pingpong mode and
                          * deflate ATO.
                          */
-                        icsk->icsk_ack.pingpong = 0;
+                        inet_csk_exit_pingpong_mode(sk);
                         icsk->icsk_ack.ato      = TCP_ATO_MIN;
                 }
                 tcp_mstamp_refresh(tcp_sk(sk));