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-rw-r--r--include/linux/tcp.h3
-rw-r--r--include/net/tcp.h2
-rw-r--r--net/ipv4/tcp.c1
-rw-r--r--net/ipv4/tcp_input.c10
-rw-r--r--net/ipv4/tcp_rate.c10
5 files changed, 19 insertions, 7 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 647532b0eb03..f50b717ce644 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -219,7 +219,8 @@ struct tcp_sock {
} rack;
u16 advmss; /* Advertised MSS */
u8 rate_app_limited:1, /* rate_{delivered,interval_us} limited? */
- unused:7;
+ is_sack_reneg:1, /* in recovery from loss with SACK reneg? */
+ unused:6;
u8 nonagle : 4,/* Disable Nagle algorithm? */
thin_lto : 1,/* Use linear timeouts for thin streams */
thin_dupack : 1,/* Fast retransmit on first dupack */
diff --git a/include/net/tcp.h b/include/net/tcp.h
index fba4fc46871d..caf35e062639 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1001,7 +1001,7 @@ void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb);
void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
struct rate_sample *rs);
void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost,
- struct skb_mstamp *now, struct rate_sample *rs);
+ bool is_sack_reneg, struct skb_mstamp *now, struct rate_sample *rs);
void tcp_rate_check_app_limited(struct sock *sk);
/* These functions determine how the current flow behaves in respect of SACK
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index dd33c785ce16..05d2bde00864 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2297,6 +2297,7 @@ int tcp_disconnect(struct sock *sk, int flags)
tp->snd_cwnd_cnt = 0;
tp->window_clamp = 0;
tcp_set_ca_state(sk, TCP_CA_Open);
+ tp->is_sack_reneg = 0;
tcp_clear_retrans(tp);
inet_csk_delack_init(sk);
/* Initialize rcv_mss to TCP_MIN_MSS to avoid division by 0
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 05255a286888..2f107e46355c 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1966,6 +1966,8 @@ void tcp_enter_loss(struct sock *sk)
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSACKRENEGING);
tp->sacked_out = 0;
tp->fackets_out = 0;
+ /* Mark SACK reneging until we recover from this loss event. */
+ tp->is_sack_reneg = 1;
}
tcp_clear_all_retrans_hints(tp);
@@ -2463,6 +2465,7 @@ static bool tcp_try_undo_recovery(struct sock *sk)
return true;
}
tcp_set_ca_state(sk, TCP_CA_Open);
+ tp->is_sack_reneg = 0;
return false;
}
@@ -2494,8 +2497,10 @@ static bool tcp_try_undo_loss(struct sock *sk, bool frto_undo)
NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPSPURIOUSRTOS);
inet_csk(sk)->icsk_retransmits = 0;
- if (frto_undo || tcp_is_sack(tp))
+ if (frto_undo || tcp_is_sack(tp)) {
tcp_set_ca_state(sk, TCP_CA_Open);
+ tp->is_sack_reneg = 0;
+ }
return true;
}
return false;
@@ -3589,6 +3594,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
struct tcp_sacktag_state sack_state;
struct rate_sample rs = { .prior_delivered = 0 };
u32 prior_snd_una = tp->snd_una;
+ bool is_sack_reneg = tp->is_sack_reneg;
u32 ack_seq = TCP_SKB_CB(skb)->seq;
u32 ack = TCP_SKB_CB(skb)->ack_seq;
bool is_dupack = false;
@@ -3711,7 +3717,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
tcp_schedule_loss_probe(sk);
delivered = tp->delivered - delivered; /* freshly ACKed or SACKed */
lost = tp->lost - lost; /* freshly marked lost */
- tcp_rate_gen(sk, delivered, lost, &now, &rs);
+ tcp_rate_gen(sk, delivered, lost, is_sack_reneg, &now, &rs);
tcp_cong_control(sk, ack, delivered, flag, &rs);
tcp_xmit_recovery(sk, rexmit);
return 1;
diff --git a/net/ipv4/tcp_rate.c b/net/ipv4/tcp_rate.c
index 9be1581a5a08..18309f58ab8d 100644
--- a/net/ipv4/tcp_rate.c
+++ b/net/ipv4/tcp_rate.c
@@ -106,7 +106,7 @@ void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
/* Update the connection delivery information and generate a rate sample. */
void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost,
- struct skb_mstamp *now, struct rate_sample *rs)
+ bool is_sack_reneg, struct skb_mstamp *now, struct rate_sample *rs)
{
struct tcp_sock *tp = tcp_sk(sk);
u32 snd_us, ack_us;
@@ -124,8 +124,12 @@ void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost,
rs->acked_sacked = delivered; /* freshly ACKed or SACKed */
rs->losses = lost; /* freshly marked lost */
- /* Return an invalid sample if no timing information is available. */
- if (!rs->prior_mstamp.v64) {
+ /* Return an invalid sample if no timing information is available or
+ * in recovery from loss with SACK reneging. Rate samples taken during
+ * a SACK reneging event may overestimate bw by including packets that
+ * were SACKed before the reneg.
+ */
+ if (!rs->prior_mstamp.v64 || is_sack_reneg) {
rs->delivered = -1;
rs->interval_us = -1;
return;