From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============2926108983514946879==" MIME-Version: 1.0 From: Mat Martineau To: mptcp at lists.01.org Subject: [MPTCP] [PATCH mptcp-next v4 10/12] mptcp: Skip unnecessary skb extension allocation for bare acks Date: Thu, 23 Jul 2020 18:11:25 -0700 Message-ID: <20200724011127.363638-11-mathew.j.martineau@linux.intel.com> In-Reply-To: 20200724011127.363638-1-mathew.j.martineau@linux.intel.com X-Status: X-Keywords: X-UID: 5286 --===============2926108983514946879== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Bare TCP ack skbs are freed right after MPTCP sees them, so the work to allocate, zero, and populate the MPTCP skb extension is wasted. Detect these skbs and do not add skb extensions to them. Signed-off-by: Mat Martineau --- net/mptcp/options.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index b4458ecd01f8..7fa822b55c34 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -868,15 +868,18 @@ void mptcp_incoming_options(struct sock *sk, struct s= k_buff *skb, if (mp_opt.use_ack) update_una(msk, &mp_opt); = - /* Zero-length packets, like bare ACKs carrying a DATA_FIN, are - * dropped by the caller and not propagated to the MPTCP layer. - * Copy the DATA_FIN information now. + /* Zero-data-length packets are dropped by the caller and not + * propagated to the MPTCP layer, so the skb extension does not + * need to be allocated or populated. DATA_FIN information, if + * present, needs to be updated here before the skb is freed. */ if (TCP_SKB_CB(skb)->seq =3D=3D TCP_SKB_CB(skb)->end_seq) { if (mp_opt.data_fin && mp_opt.data_len =3D=3D 1 && mptcp_update_rcv_data_fin(msk, mp_opt.data_seq) && schedule_work(&msk->work)) sock_hold(subflow->conn); + + return; } = mpext =3D skb_ext_add(skb, SKB_EXT_MPTCP); -- = 2.27.0 --===============2926108983514946879==--