From: Eric Dumazet <edumazet@google.com>
Date: Tue, 18 Nov 2014 07:06:20 +0000 (-0800)
Subject: tcp: make connect() mem charging friendly
X-Git-Tag: v3.2.69~16
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3e2eb8946907b2d53eb906e13e01d273c6534f5c;p=pandora-kernel.git

tcp: make connect() mem charging friendly

[ Upstream commit 355a901e6cf1b2b763ec85caa2a9f04fbcc4ab4a ]

While working on sk_forward_alloc problems reported by Denys
Fedoryshchenko, we found that tcp connect() (and fastopen) do not call
sk_wmem_schedule() for SYN packet (and/or SYN/DATA packet), so
sk_forward_alloc is negative while connect is in progress.

We can fix this by calling regular sk_stream_alloc_skb() both for the
SYN packet (in tcp_connect()) and the syn_data packet in
tcp_send_syn_data()

Then, tcp_send_syn_data() can avoid copying syn_data as we simply
can manipulate syn_data->cb[] to remove SYN flag (and increment seq)

Instead of open coding memcpy_fromiovecend(), simply use this helper.

This leaves in socket write queue clean fast clone skbs.

This was tested against our fastopen packetdrill tests.

Reported-by: Denys Fedoryshchenko <nuclearcat@nuclearcat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2:
 - Drop the Fast Open changes
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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