From 40bf5450ba6fb587b54a9e19abc41412c8f8b825 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 19 Nov 2020 11:45:56 -0800 Subject: [PATCH] mptcp: skip to next candidate if subflow has unacked data [ Upstream commit 860975c6f80adae9d2c7654bde04a99dd28bc94f ] In case a subflow path is blocked, MPTCP-level retransmit may not take place anymore because such subflow is likely to have unacked data left in its write queue. Ignore subflows that have experienced loss and test next candidate. Fixes: 3b1d6210a95773691 ("mptcp: implement and use MPTCP-level retransmission") Signed-off-by: Florian Westphal Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/mptcp/protocol.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 967ce9ccfc0d..f56b2e331bb6 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1648,8 +1648,11 @@ static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk) continue; /* still data outstanding at TCP level? Don't retransmit. */ - if (!tcp_write_queue_empty(ssk)) + if (!tcp_write_queue_empty(ssk)) { + if (inet_csk(ssk)->icsk_ca_state >= TCP_CA_Loss) + continue; return NULL; + } if (subflow->backup) { if (!backup) -- 2.17.1