From: Eric Dumazet <edumazet@google.com>
Date: Sat, 26 Oct 2013 00:26:17 +0000 (-0700)
Subject: tcp: gso: fix truesize tracking
X-Git-Tag: omap-for-v3.13/fixes-for-merge-window-take2~67^2~18
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0d08c42cf9a71530fef5ebcfe368f38f2dd0476f;p=pandora-kernel.git

tcp: gso: fix truesize tracking

commit 6ff50cd55545 ("tcp: gso: do not generate out of order packets")
had an heuristic that can trigger a warning in skb_try_coalesce(),
because skb->truesize of the gso segments were exactly set to mss.

This breaks the requirement that

skb->truesize >= skb->len + truesizeof(struct sk_buff);

It can trivially be reproduced by :

ifconfig lo mtu 1500
ethtool -K lo tso off
netperf

As the skbs are looped into the TCP networking stack, skb_try_coalesce()
warns us of these skb under-estimating their truesize.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

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