[PATCH net 01/10] mptcp: fix missing wakeups in edge scenarios

[Matthieu Baerts (NGI0)]

From: Paolo Abeni <pabeni@xxxxxxxxxx>

The mptcp_recvmsg() can fill MPTCP socket receive queue via
mptcp_move_skbs(), but currently does not try to wakeup any listener,
because the same process is going to check the receive queue soon.

When multiple threads are reading from the same fd, the above can
cause stall. Add the missing wakeup.

Fixes: 6771bfd9ee24 ("mptcp: update mptcp ack sequence from work queue")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
 net/mptcp/protocol.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index a72a6ad6ee8b..5a20ab2789ae 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2276,6 +2276,10 @@ static bool mptcp_move_skbs(struct sock *sk)
 		mptcp_backlog_spooled(sk, moved, &skbs);
 	}
 	mptcp_data_unlock(sk);
+
+	if (enqueued && mptcp_epollin_ready(sk))
+		sk->sk_data_ready(sk);
+
 	return enqueued;
 }
 

-- 
2.53.0