[PATCH net-next] mptcp: don't skip needed ack

[Paolo Abeni]

Currently we skip calling tcp_cleanup_rbuf() when packets
are moved into the OoO queue or simply dropped. In both
cases we still increment tp->copied_seq, and we should
ask the TCP stack to check for ack.

Fixes: c76c6956566f ("mptcp: call tcp_cleanup_rbuf on subflows")
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
 net/mptcp/protocol.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 34c037731f35..f483eab0081a 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -454,10 +454,12 @@ static bool __mptcp_move_skbs_from_subflow(struct 
mptcp_sock *msk,
        unsigned int moved = 0;
        bool more_data_avail;
        struct tcp_sock *tp;
+       u32 old_copied_seq;
        bool done = false;
 
        pr_debug("msk=%p ssk=%p", msk, ssk);
        tp = tcp_sk(ssk);
+       old_copied_seq = tp->copied_seq;
        do {
                u32 map_remaining, offset;
                u32 seq = tp->copied_seq;
@@ -516,8 +518,8 @@ static bool __mptcp_move_skbs_from_subflow(struct 
mptcp_sock *msk,
        } while (more_data_avail);
 
        *bytes += moved;
-       if (moved)
-               tcp_cleanup_rbuf(ssk, moved);
+       if (tp->copied_seq != old_copied_seq)
+               tcp_cleanup_rbuf(ssk, 1);
 
        return done;
 }
-- 
2.26.2