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authorYuchung Cheng <ycheng@google.com>2017-01-12 22:11:31 -0800
committerDavid S. Miller <davem@davemloft.net>2017-01-13 22:37:16 -0500
commite636f8b0104d6622aaaed6aa5ef17dfbf165bc51 (patch)
treedf39c0f942ddcab2869d408414f562ae208ddea9 /net
parentdb8da6bb574e1692cb86624317c572b0b9306560 (diff)
tcp: new helper for RACK to detect loss
Create a new helper tcp_rack_detect_loss to prepare the upcoming RACK reordering timer patch. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_input.c12
-rw-r--r--net/ipv4/tcp_recovery.c22
2 files changed, 21 insertions, 13 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index ec6d84363024..bb24b93e64bc 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2865,10 +2865,14 @@ static void tcp_fastretrans_alert(struct sock *sk, const int acked,
}
/* Use RACK to detect loss */
- if (sysctl_tcp_recovery & TCP_RACK_LOST_RETRANS &&
- tcp_rack_mark_lost(sk)) {
- flag |= FLAG_LOST_RETRANS;
- *ack_flag |= FLAG_LOST_RETRANS;
+ if (sysctl_tcp_recovery & TCP_RACK_LOST_RETRANS) {
+ u32 prior_retrans = tp->retrans_out;
+
+ tcp_rack_mark_lost(sk);
+ if (prior_retrans > tp->retrans_out) {
+ flag |= FLAG_LOST_RETRANS;
+ *ack_flag |= FLAG_LOST_RETRANS;
+ }
}
/* E. Process state. */
diff --git a/net/ipv4/tcp_recovery.c b/net/ipv4/tcp_recovery.c
index f38dba5aed7a..7ea0377229c0 100644
--- a/net/ipv4/tcp_recovery.c
+++ b/net/ipv4/tcp_recovery.c
@@ -32,17 +32,11 @@ static void tcp_rack_mark_skb_lost(struct sock *sk, struct sk_buff *skb)
* The current version is only used after recovery starts but can be
* easily extended to detect the first loss.
*/
-int tcp_rack_mark_lost(struct sock *sk)
+static void tcp_rack_detect_loss(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
- u32 reo_wnd, prior_retrans = tp->retrans_out;
-
- if (inet_csk(sk)->icsk_ca_state < TCP_CA_Recovery || !tp->rack.advanced)
- return 0;
-
- /* Reset the advanced flag to avoid unnecessary queue scanning */
- tp->rack.advanced = 0;
+ u32 reo_wnd;
/* To be more reordering resilient, allow min_rtt/4 settling delay
* (lower-bounded to 1000uS). We use min_rtt instead of the smoothed
@@ -82,7 +76,17 @@ int tcp_rack_mark_lost(struct sock *sk)
break;
}
}
- return prior_retrans - tp->retrans_out;
+}
+
+void tcp_rack_mark_lost(struct sock *sk)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ if (inet_csk(sk)->icsk_ca_state < TCP_CA_Recovery || !tp->rack.advanced)
+ return;
+ /* Reset the advanced flag to avoid unnecessary queue scanning */
+ tp->rack.advanced = 0;
+ tcp_rack_detect_loss(sk);
}
/* Record the most recently (re)sent time among the (s)acked packets */