Patchwork [net-next,06/17] tcp: fix corner case issue in segmentation during rexmitting

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Submitter Ilpo Järvinen
Date Feb. 28, 2009, 2:44 p.m.
Message ID <12358322831953-git-send-email-ilpo.jarvinen@helsinki.fi>
Download mbox | patch
Permalink /patch/23885/
State Accepted
Delegated to: David Miller
Headers show

Comments

Ilpo Järvinen - Feb. 28, 2009, 2:44 p.m.
From: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>

If cur_mss grew very recently so that the previously G/TSOed skb
now fits well into a single segment it would get send up in
parts unless we calculate # of segments again. This corner-case
could happen eg. after mtu probe completes or less than
previously sack blocks are required for the opposite direction.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
---
 net/ipv4/tcp_output.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
David Miller - March 2, 2009, 11:01 a.m.
From: "Ilpo Järvinen" <ilpo.jarvinen@helsinki.fi>
Date: Sat, 28 Feb 2009 16:44:31 +0200

> From: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
> 
> If cur_mss grew very recently so that the previously G/TSOed skb
> now fits well into a single segment it would get send up in
> parts unless we calculate # of segments again. This corner-case
> could happen eg. after mtu probe completes or less than
> previously sack blocks are required for the opposite direction.
> 
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>

Applied.
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Patch

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 3feab4d..77af7fa 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1921,6 +1921,8 @@  int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 	if (skb->len > cur_mss) {
 		if (tcp_fragment(sk, skb, cur_mss, cur_mss))
 			return -ENOMEM; /* We'll try again later. */
+	} else {
+		tcp_init_tso_segs(sk, skb, cur_mss);
 	}
 
 	tcp_retrans_try_collapse(sk, skb, cur_mss);