[MPTCP] [PATCH mptcp-next 2/2] mptcp: fix poll after shutdown

[MPTCP] [PATCH mptcp-next 2/2] mptcp: fix poll after shutdown

[Paolo Abeni]

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The current mptcp_poll() implementation gives unexpected
results after shutdown(SEND_SHUTDOWN) and after receiving
a MP_RESET.

Set the correct mask.

Signed-off-by: Paolo Abeni <pabeni(a)redhat.com>
---
 net/mptcp/protocol.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index fdd2a30118978..305d25cbc216a 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3322,7 +3322,7 @@ static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
 	struct sock *sk = (struct sock *)msk;
 
 	if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
-		return 0;
+		return EPOLLOUT | EPOLLWRNORM;
 
 	if (sk_stream_is_writeable(sk))
 		return EPOLLOUT | EPOLLWRNORM;
@@ -3355,6 +3355,8 @@ static __poll_t mptcp_poll(struct file *file, struct socket *sock,
 		mask |= mptcp_check_readable(msk);
 		mask |= mptcp_check_writeable(msk);
 	}
+	if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
+		mask |= EPOLLHUP;
 	if (sk->sk_shutdown & RCV_SHUTDOWN)
 		mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
 
-- 
2.26.2