Address comments from Clashiko [1]:
- mib: typo: "constrains" -> "constraints".
- mptcp_over_limit: precise it is not only 0-win, but retrans, dup or
old acks.
- mptcp_over_limit: bump LINUX_MIB_TCPRCVQDROP, as previously discussed
in [2].
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260724-net-next-mptcp-oooq-pruning-v1-0-5dd4dec63a54%40kernel.org?part=3 [1]
Link: https://lore.kernel.org/b5244dd4-205d-4abd-8ea5-fd879a97038f@redhat.com
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
net/mptcp/mib.h | 2 +-
net/mptcp/options.c | 6 +++++-
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h
index 18f35f7e0a2d..25f360724c57 100644
--- a/net/mptcp/mib.h
+++ b/net/mptcp/mib.h
@@ -89,7 +89,7 @@ enum linux_mptcp_mib_field {
MPTCP_MIB_FALLBACKFAILED, /* Can't fallback due to msk status */
MPTCP_MIB_WINPROBE, /* MPTCP-level zero window probe */
MPTCP_MIB_BACKLOGDROP, /* Backlog over memory limit */
- MPTCP_MIB_RCVPRUNED, /* Dropped due to memory constrains */
+ MPTCP_MIB_RCVPRUNED, /* Dropped due to memory constraints */
MPTCP_MIB_OFO_PRUNED, /* MPTCP-level OoO queue pruned */
__MPTCP_MIB_MAX
};
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index d6b009319839..7c0bce3780c5 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1193,7 +1193,7 @@ static bool mptcp_over_limit(struct sock *sk, struct sock *ssk,
if (likely(mem <= READ_ONCE(sk->sk_rcvbuf)))
return false;
- /* Avoid silently dropping pure acks, fin or zero win probes. */
+ /* Avoid silently dropping pure acks, fin or already-acked segments. */
if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq ||
TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN ||
!after(TCP_SKB_CB(skb)->end_seq, tcp_sk(ssk)->rcv_nxt))
@@ -1202,6 +1202,10 @@ static bool mptcp_over_limit(struct sock *sk, struct sock *ssk,
/* Dropped due to memory constraints, schedule an ack. */
inet_csk(ssk)->icsk_ack.pending |= ICSK_ACK_NOMEM | ICSK_ACK_NOW;
inet_csk_schedule_ack(ssk);
+
+ /* In fallback mode: skb is dropped before the TCP recv queue. */
+ NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP);
+
return true;
}
--
2.53.0