From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754236AbcAETwI (ORCPT ); Tue, 5 Jan 2016 14:52:08 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:45731 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754097AbcAETtg (ORCPT ); Tue, 5 Jan 2016 14:49:36 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Eric Dumazet , Al Viro , "David S. Miller" , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 208/211] tcp: restore fastopen with no data in SYN packet Date: Tue, 5 Jan 2016 11:45:16 -0800 Message-Id: <1452023119-25647-209-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1452023119-25647-1-git-send-email-kamal@canonical.com> References: <1452023119-25647-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 07e100f984975cb0417a7d5e626d0409efbad478 ] Yuchung tracked a regression caused by commit 57be5bdad759 ("ip: convert tcp_sendmsg() to iov_iter primitives") for TCP Fast Open. Some Fast Open users do not actually add any data in the SYN packet. Fixes: 57be5bdad759 ("ip: convert tcp_sendmsg() to iov_iter primitives") Reported-by: Yuchung Cheng Signed-off-by: Eric Dumazet Cc: Al Viro Acked-by: Yuchung Cheng Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- net/ipv4/tcp_output.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 747a4c4..71bbadd 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3148,7 +3148,7 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn) { struct tcp_sock *tp = tcp_sk(sk); struct tcp_fastopen_request *fo = tp->fastopen_req; - int syn_loss = 0, space, err = 0, copied; + int syn_loss = 0, space, err = 0; unsigned long last_syn_loss = 0; struct sk_buff *syn_data; @@ -3186,17 +3186,18 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn) goto fallback; syn_data->ip_summed = CHECKSUM_PARTIAL; memcpy(syn_data->cb, syn->cb, sizeof(syn->cb)); - copied = copy_from_iter(skb_put(syn_data, space), space, - &fo->data->msg_iter); - if (unlikely(!copied)) { - kfree_skb(syn_data); - goto fallback; - } - if (copied != space) { - skb_trim(syn_data, copied); - space = copied; + if (space) { + int copied = copy_from_iter(skb_put(syn_data, space), space, + &fo->data->msg_iter); + if (unlikely(!copied)) { + kfree_skb(syn_data); + goto fallback; + } + if (copied != space) { + skb_trim(syn_data, copied); + space = copied; + } } - /* No more data pending in inet_wait_for_connect() */ if (space == fo->size) fo->data = NULL; -- 1.9.1