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>

diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index fe0d9b4..179609d 100644 (file)
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -314,4 +314,21 @@ int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
                               char __user *optval, unsigned int optlen);
 
 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
+
+#define TCP_PINGPONG_THRESH    1
+
+static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
+{
+       inet_csk(sk)->icsk_ack.pingpong = TCP_PINGPONG_THRESH;
+}
+
+static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
+{
+       inet_csk(sk)->icsk_ack.pingpong = 0;
+}
+
+static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
+{
+       return inet_csk(sk)->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
+}
 #endif /* _INET_CONNECTION_SOCK_H */

diff --git a/net/dccp/input.c b/net/dccp/input.c
index 85d6c87..8d03707 100644 (file)
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -480,7 +480,7 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk,
                        sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
                }
 
-               if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
+               if (sk->sk_write_pending || inet_csk_in_pingpong_mode(sk) ||
                    icsk->icsk_accept_queue.rskq_defer_accept) {
                        /* Save one ACK. Data will be ready after
                         * several ticks, if write_pending is set.

diff --git a/net/dccp/timer.c b/net/dccp/timer.c
index 1501a20..74e1384 100644 (file)
--- a/net/dccp/timer.c
+++ b/net/dccp/timer.c
@@ -199,7 +199,7 @@ static void dccp_delack_timer(struct timer_list *t)
        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);
@@ -207,7 +207,7 @@ static void dccp_delack_timer(struct timer_list *t)
                        /* 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;
                }
                dccp_send_ack(sk);

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 12ba214..6f8d292 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1551,7 +1551,7 @@ static void tcp_cleanup_rbuf(struct sock *sk, int copied)
                    (copied > 0 &&
                     ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
                      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
-                      !icsk->icsk_ack.pingpong)) &&
+                      !inet_csk_in_pingpong_mode(sk))) &&
                      !atomic_read(&sk->sk_rmem_alloc)))
                        time_to_ack = true;
        }
@@ -2984,16 +2984,16 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
 
        case TCP_QUICKACK:
                if (!val) {
-                       icsk->icsk_ack.pingpong = 1;
+                       inet_csk_enter_pingpong_mode(sk);
                } else {
-                       icsk->icsk_ack.pingpong = 0;
+                       inet_csk_exit_pingpong_mode(sk);
                        if ((1 << sk->sk_state) &
                            (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
                            inet_csk_ack_scheduled(sk)) {
                                icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
                                tcp_cleanup_rbuf(sk, 1);
                                if (!(val & 1))
-                                       icsk->icsk_ack.pingpong = 1;
+                                       inet_csk_enter_pingpong_mode(sk);
                        }
                }
                break;
@@ -3407,7 +3407,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
                return 0;
        }
        case TCP_QUICKACK:
-               val = !icsk->icsk_ack.pingpong;
+               val = !inet_csk_in_pingpong_mode(sk);
                break;
 
        case TCP_CONGESTION:

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 76858b1..7a027de 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -221,7 +221,7 @@ void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks)
        struct inet_connection_sock *icsk = inet_csk(sk);
 
        tcp_incr_quickack(sk, max_quickacks);
-       icsk->icsk_ack.pingpong = 0;
+       inet_csk_exit_pingpong_mode(sk);
        icsk->icsk_ack.ato = TCP_ATO_MIN;
 }
 EXPORT_SYMBOL(tcp_enter_quickack_mode);
@@ -236,7 +236,7 @@ static bool tcp_in_quickack_mode(struct sock *sk)
        const struct dst_entry *dst = __sk_dst_get(sk);
 
        return (dst && dst_metric(dst, RTAX_QUICKACK)) ||
-               (icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong);
+               (icsk->icsk_ack.quick && !inet_csk_in_pingpong_mode(sk));
 }
 
 static void tcp_ecn_queue_cwr(struct tcp_sock *tp)
@@ -4094,7 +4094,7 @@ void tcp_fin(struct sock *sk)
        case TCP_ESTABLISHED:
                /* Move to CLOSE_WAIT */
                tcp_set_state(sk, TCP_CLOSE_WAIT);
-               inet_csk(sk)->icsk_ack.pingpong = 1;
+               inet_csk_enter_pingpong_mode(sk);
                break;
 
        case TCP_CLOSE_WAIT:
@@ -5889,7 +5889,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
                        return -1;
                if (sk->sk_write_pending ||
                    icsk->icsk_accept_queue.rskq_defer_accept ||
-                   icsk->icsk_ack.pingpong) {
+                   inet_csk_in_pingpong_mode(sk)) {
                        /* Save one ACK. Data will be ready after
                         * several ticks, if write_pending is set.
                         *

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index efc6fef..662b034 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2437,7 +2437,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
                refcount_read(&sk->sk_refcnt), sk,
                jiffies_to_clock_t(icsk->icsk_rto),
                jiffies_to_clock_t(icsk->icsk_ack.ato),
-               (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
+               (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sk),
                tp->snd_cwnd,
                state == TCP_LISTEN ?
                    fastopenq->max_qlen :

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 26a2948..06228e2 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -171,7 +171,7 @@ static void tcp_event_data_sent(struct tcp_sock *tp,
         * packet, enter pingpong mode.
         */
        if ((u32)(now - icsk->icsk_ack.lrcvtime) < icsk->icsk_ack.ato)
-               icsk->icsk_ack.pingpong = 1;
+               inet_csk_enter_pingpong_mode(sk);
 }
 
 /* Account for an ACK we sent. */
@@ -3569,7 +3569,7 @@ void tcp_send_delayed_ack(struct sock *sk)
                const struct tcp_sock *tp = tcp_sk(sk);
                int max_ato = HZ / 2;
 
-               if (icsk->icsk_ack.pingpong ||
+               if (inet_csk_in_pingpong_mode(sk) ||
                    (icsk->icsk_ack.pending & ICSK_ACK_PUSHED))
                        max_ato = TCP_DELACK_MAX;
 

diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index d7399a8..f0c8639 100644 (file)
--- 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));

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index b81eb7c..e51cda7 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1864,7 +1864,7 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
                   refcount_read(&sp->sk_refcnt), sp,
                   jiffies_to_clock_t(icsk->icsk_rto),
                   jiffies_to_clock_t(icsk->icsk_ack.ato),
-                  (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
+                  (icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(sp),
                   tp->snd_cwnd,
                   state == TCP_LISTEN ?
                        fastopenq->max_qlen :