mptcp: skip to next candidate if subflow has unacked data
authorFlorian Westphal <fw@strlen.de>
Thu, 19 Nov 2020 19:45:56 +0000 (11:45 -0800)
committerJakub Kicinski <kuba@kernel.org>
Fri, 20 Nov 2020 23:33:24 +0000 (15:33 -0800)
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 <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net/mptcp/protocol.c

index 2d45086..868c76c 100644 (file)
@@ -1726,8 +1726,11 @@ 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)