Commit b6b6d653 authored Sep 30, 2020 by Eric Dumazet Committed by David S. Miller Sep 30, 2020

inet: remove icsk_ack.blocked



TCP has been using it to work around the possibility of tcp_delack_timer()
finding the socket owned by user.

After commit 6f458dfb ("tcp: improve latencies of timer triggered events")
we added TCP_DELACK_TIMER_DEFERRED atomic bit for more immediate recovery,
so we can get rid of icsk_ack.blocked

This frees space that following patch will reuse.

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>

parent 20c168be

include/net/inet_connection_sock.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -110,7 +110,7 @@ struct inet_connection_sock {
		__u8 pending; /* ACK is pending */
		__u8 quick; /* Scheduled number of quick acks */
		__u8 pingpong; /* The session is interactive */
		__u8 blocked; /* Delayed ACK was blocked by socket lock */
		/* one byte hole. */
		__u32 ato; /* Predicted tick of soft clock */
		unsigned long timeout; /* Currently scheduled timeout */
		__u32 lrcvtime; /* timestamp of last received data packet */
		@@ -198,7 +198,7 @@ static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
		sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
		#endif
		} else if (what == ICSK_TIME_DACK) {
		icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
		icsk->icsk_ack.pending = 0;
		#ifdef INET_CSK_CLEAR_TIMERS
		sk_stop_timer(sk, &icsk->icsk_delack_timer);
		#endif

net/dccp/timer.c

+0 −1

Original line number	Diff line number	Diff line
		@@ -176,7 +176,6 @@ static void dccp_delack_timer(struct timer_list *t)
		bh_lock_sock(sk);
		if (sock_owned_by_user(sk)) {
		/* Try again later. */
		icsk->icsk_ack.blocked = 1;
		__NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED);
		sk_reset_timer(sk, &icsk->icsk_delack_timer,
		jiffies + TCP_DELACK_MIN);

net/ipv4/inet_connection_sock.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -564,7 +564,7 @@ void inet_csk_clear_xmit_timers(struct sock *sk)
		{
		struct inet_connection_sock *icsk = inet_csk(sk);

		icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;
		icsk->icsk_pending = icsk->icsk_ack.pending = 0;

		sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
		sk_stop_timer(sk, &icsk->icsk_delack_timer);

net/ipv4/tcp.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -1538,10 +1538,8 @@ void tcp_cleanup_rbuf(struct sock *sk, int copied)

		if (inet_csk_ack_scheduled(sk)) {
		const struct inet_connection_sock *icsk = inet_csk(sk);
		/* Delayed ACKs frequently hit locked sockets during bulk
		* receive. */
		if (icsk->icsk_ack.blocked \|\|
		/* Once-per-two-segments ACK was not sent by tcp_input.c */

		if (/* Once-per-two-segments ACK was not sent by tcp_input.c */
		tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss \|\|
		/*
		* If this read emptied read buffer, we send ACK, if

net/ipv4/tcp_output.c

+2 −5

Original line number	Diff line number	Diff line
		@@ -3911,11 +3911,8 @@ void tcp_send_delayed_ack(struct sock *sk)

		/* Use new timeout only if there wasn't a older one earlier. */
		if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
		/* If delack timer was blocked or is about to expire,
		* send ACK now.
		*/
		if (icsk->icsk_ack.blocked \|\|
		time_before_eq(icsk->icsk_ack.timeout, jiffies + (ato >> 2))) {
		/* If delack timer is about to expire, send ACK now. */
		if (time_before_eq(icsk->icsk_ack.timeout, jiffies + (ato >> 2))) {
		tcp_send_ack(sk);
		return;
		}