diff mbox series

[net-next,03/10] mptcp: skip to next candidate if subflow has unacked data

Message ID 20201119194603.103158-4-mathew.j.martineau@linux.intel.com (mailing list archive)
State Accepted
Delegated to: Netdev Maintainers
Headers show
Series mptcp: More miscellaneous MPTCP fixes | expand

Checks

Context Check Description
netdev/cover_letter success Link
netdev/fixes_present success Link
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for net-next
netdev/subject_prefix success Link
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 6 this patch: 6
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 12 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 6 this patch: 6
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Mat Martineau Nov. 19, 2020, 7:45 p.m. UTC 
From: Florian Westphal <fw@strlen.de>

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>
---
 net/mptcp/protocol.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index a46a542b1766..806c0658e42f 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1725,8 +1725,11 @@  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)