4.17-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit 9a9c9b51e54618861420093ae6e9b50a961914c5 ]
We want to add finer control of the number of ACK packets sent after ECN events.
This patch is not changing current behavior, it only enables following change.
Signed-off-by: Eric Dumazet edumazet@google.com Acked-by: Soheil Hassas Yeganeh soheil@google.com Acked-by: Neal Cardwell ncardwell@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/tcp.h | 2 +- net/ipv4/tcp_dctcp.c | 4 ++-- net/ipv4/tcp_input.c | 24 +++++++++++++----------- 3 files changed, 16 insertions(+), 14 deletions(-)
--- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -342,7 +342,7 @@ ssize_t tcp_splice_read(struct socket *s struct pipe_inode_info *pipe, size_t len, unsigned int flags);
-void tcp_enter_quickack_mode(struct sock *sk); +void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks); static inline void tcp_dec_quickack_mode(struct sock *sk, const unsigned int pkts) { --- a/net/ipv4/tcp_dctcp.c +++ b/net/ipv4/tcp_dctcp.c @@ -138,7 +138,7 @@ static void dctcp_ce_state_0_to_1(struct */ if (inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER) __tcp_send_ack(sk, ca->prior_rcv_nxt); - tcp_enter_quickack_mode(sk); + tcp_enter_quickack_mode(sk, 1); }
ca->prior_rcv_nxt = tp->rcv_nxt; @@ -159,7 +159,7 @@ static void dctcp_ce_state_1_to_0(struct */ if (inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER) __tcp_send_ack(sk, ca->prior_rcv_nxt); - tcp_enter_quickack_mode(sk); + tcp_enter_quickack_mode(sk, 1); }
ca->prior_rcv_nxt = tp->rcv_nxt; --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -184,21 +184,23 @@ static void tcp_measure_rcv_mss(struct s } }
-static void tcp_incr_quickack(struct sock *sk) +static void tcp_incr_quickack(struct sock *sk, unsigned int max_quickacks) { struct inet_connection_sock *icsk = inet_csk(sk); unsigned int quickacks = tcp_sk(sk)->rcv_wnd / (2 * icsk->icsk_ack.rcv_mss);
if (quickacks == 0) quickacks = 2; + quickacks = min(quickacks, max_quickacks); if (quickacks > icsk->icsk_ack.quick) - icsk->icsk_ack.quick = min(quickacks, TCP_MAX_QUICKACKS); + icsk->icsk_ack.quick = quickacks; }
-void tcp_enter_quickack_mode(struct sock *sk) +void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks) { struct inet_connection_sock *icsk = inet_csk(sk); - tcp_incr_quickack(sk); + + tcp_incr_quickack(sk, max_quickacks); icsk->icsk_ack.pingpong = 0; icsk->icsk_ack.ato = TCP_ATO_MIN; } @@ -243,7 +245,7 @@ static void __tcp_ecn_check_ce(struct tc * it is probably a retransmit. */ if (tp->ecn_flags & TCP_ECN_SEEN) - tcp_enter_quickack_mode((struct sock *)tp); + tcp_enter_quickack_mode((struct sock *)tp, TCP_MAX_QUICKACKS); break; case INET_ECN_CE: if (tcp_ca_needs_ecn((struct sock *)tp)) @@ -251,7 +253,7 @@ static void __tcp_ecn_check_ce(struct tc
if (!(tp->ecn_flags & TCP_ECN_DEMAND_CWR)) { /* Better not delay acks, sender can have a very low cwnd */ - tcp_enter_quickack_mode((struct sock *)tp); + tcp_enter_quickack_mode((struct sock *)tp, TCP_MAX_QUICKACKS); tp->ecn_flags |= TCP_ECN_DEMAND_CWR; } tp->ecn_flags |= TCP_ECN_SEEN; @@ -666,7 +668,7 @@ static void tcp_event_data_recv(struct s /* The _first_ data packet received, initialize * delayed ACK engine. */ - tcp_incr_quickack(sk); + tcp_incr_quickack(sk, TCP_MAX_QUICKACKS); icsk->icsk_ack.ato = TCP_ATO_MIN; } else { int m = now - icsk->icsk_ack.lrcvtime; @@ -682,7 +684,7 @@ static void tcp_event_data_recv(struct s /* Too long gap. Apparently sender failed to * restart window, so that we send ACKs quickly. */ - tcp_incr_quickack(sk); + tcp_incr_quickack(sk, TCP_MAX_QUICKACKS); sk_mem_reclaim(sk); } } @@ -4136,7 +4138,7 @@ static void tcp_send_dupack(struct sock if (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq && before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) { NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOST); - tcp_enter_quickack_mode(sk); + tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);
if (tcp_is_sack(tp) && sock_net(sk)->ipv4.sysctl_tcp_dsack) { u32 end_seq = TCP_SKB_CB(skb)->end_seq; @@ -4667,7 +4669,7 @@ queue_and_out: tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
out_of_window: - tcp_enter_quickack_mode(sk); + tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS); inet_csk_schedule_ack(sk); drop: tcp_drop(sk, skb); @@ -5744,7 +5746,7 @@ static int tcp_rcv_synsent_state_process * to stand against the temptation 8) --ANK */ inet_csk_schedule_ack(sk); - tcp_enter_quickack_mode(sk); + tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS); inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, TCP_DELACK_MAX, TCP_RTO_MAX);