This is a note to let you know that I've just added the patch titled
tcp: fix for zero packets_in_flight was too broad
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tcp-fix-for-zero-packets_in_flight-was-too-broad.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From b966c5b50d728a0fe67becadf5544a5239b32098 Mon Sep 17 00:00:00 2001
From: Ilpo Järvinen <[email protected]>
Date: Mon, 4 Feb 2013 02:14:25 +0000
Subject: tcp: fix for zero packets_in_flight was too broad
From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <[email protected]>
[ Upstream commit 6731d2095bd4aef18027c72ef845ab1087c3ba63 ]
There are transients during normal FRTO procedure during which
the packets_in_flight can go to zero between write_queue state
updates and firing the resulting segments out. As FRTO processing
occurs during that window the check must be more precise to
not match "spuriously" :-). More specificly, e.g., when
packets_in_flight is zero but FLAG_DATA_ACKED is true the problematic
branch that set cwnd into zero would not be taken and new segments
might be sent out later.
Signed-off-by: Ilpo Järvinen <[email protected]>
Tested-by: Eric Dumazet <[email protected]>
Acked-by: Neal Cardwell <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
net/ipv4/tcp_input.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3619,8 +3619,7 @@ static int tcp_process_frto(struct sock
((tp->frto_counter >= 2) && (flag & FLAG_RETRANS_DATA_ACKED)))
tp->undo_marker = 0;
- if (!before(tp->snd_una, tp->frto_highmark) ||
- !tcp_packets_in_flight(tp)) {
+ if (!before(tp->snd_una, tp->frto_highmark)) {
tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 2 : 3), flag);
return 1;
}
@@ -3640,6 +3639,11 @@ static int tcp_process_frto(struct sock
}
} else {
if (!(flag & FLAG_DATA_ACKED) && (tp->frto_counter == 1)) {
+ if (!tcp_packets_in_flight(tp)) {
+ tcp_enter_frto_loss(sk, 2, flag);
+ return true;
+ }
+
/* Prevent sending of new data. */
tp->snd_cwnd = min(tp->snd_cwnd,
tcp_packets_in_flight(tp));
Patches currently in stable-queue which might be from [email protected]
are
queue-3.4/tcp-frto-should-not-set-snd_cwnd-to-0.patch
queue-3.4/tcp-fix-for-zero-packets_in_flight-was-too-broad.patch
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