mptcp: Skip unnecessary skb extension allocation for bare acks (06827b34) · Commits · 戴 / test

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 <mathew.j.martineau@linux.intel.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/mptcp/options.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -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);

Admin message