From f03afb3aeb9d81f6c5ab728a61a040012923e3b3 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Tue, 18 Feb 2025 19:36:13 +0100 Subject: mptcp: drop __mptcp_fastopen_gen_msk_ackseq() When we will move the whole RX path under the msk socket lock, updating the already queued skb for passive fastopen socket at 3rd ack time will be extremely painful and race prone The map_seq for already enqueued skbs is used only to allow correct coalescing with later data; preventing collapsing to the first skb of a fastopen connect we can completely remove the __mptcp_fastopen_gen_msk_ackseq() helper. Before dropping this helper, a new item had to be added to the mptcp_skb_cb structure. Because this item will be frequently tested in the fast path -- almost on every packet -- and because there is free space there, a single byte is used instead of a bitfield. This micro optimisation slightly reduces the number of CPU operations to do the associated check. Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250218-net-next-mptcp-rx-path-refactor-v1-2-4a47d90d7998@kernel.org Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net/mptcp/protocol.c') diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 6bd819047470..55f9698f3c22 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -135,7 +135,8 @@ static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to, bool fragstolen; int delta; - if (MPTCP_SKB_CB(from)->offset || + if (unlikely(MPTCP_SKB_CB(to)->cant_coalesce) || + MPTCP_SKB_CB(from)->offset || ((to->len + from->len) > (sk->sk_rcvbuf >> 3)) || !skb_try_coalesce(to, from, &fragstolen, &delta)) return false; @@ -366,6 +367,7 @@ static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len; MPTCP_SKB_CB(skb)->offset = offset; MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp; + MPTCP_SKB_CB(skb)->cant_coalesce = 0; if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) { /* in sequence */ -- cgit v1.2.3-59-g8ed1b