tree 217decbcda0ccdbf118ed819888b09d888f6acfd
parent e64701b912ea8bd58bca9c5d31638a11a6b47b5e
author Eric Dumazet <edumazet@google.com> 1416294380 -0800
committer Stefan Bader <stefan.bader@canonical.com> 1432893257 +0200

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>
(cherry picked from commit 3e2eb8946907b2d53eb906e13e01d273c6534f5c)

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>