From 06827b348b1d43850a63c3e490fe9712c124fa0c Mon Sep 17 00:00:00 2001 From: Mat Martineau Date: Tue, 28 Jul 2020 15:12:08 -0700 Subject: mptcp: Skip unnecessary skb extension allocation for bare acks 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 Signed-off-by: David S. Miller --- net/mptcp/options.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'net/mptcp') 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 sk_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 == TCP_SKB_CB(skb)->end_seq) { if (mp_opt.data_fin && mp_opt.data_len == 1 && mptcp_update_rcv_data_fin(msk, mp_opt.data_seq) && schedule_work(&msk->work)) sock_hold(subflow->conn); + + return; } mpext = skb_ext_add(skb, SKB_EXT_MPTCP); -- cgit v1.2.3