This clean the code a bit, and avoid skipping msk receive
buffer update on some weird corner case.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/protocol.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 970da88cd04f..5af3d591a20b 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -642,6 +642,10 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk,
 		}
 	}
 
+	/* over limit? can't append more skbs to msk */
+	if (__mptcp_rmem(sk) > sk_rbuf)
+		return true;
+
 	pr_debug("msk=%p ssk=%p", msk, ssk);
 	tp = tcp_sk(ssk);
 	do {
@@ -786,8 +790,6 @@ static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
 void mptcp_data_ready(struct sock *sk, struct sock *ssk)
 {
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
-	struct mptcp_sock *msk = mptcp_sk(sk);
-	int sk_rbuf, ssk_rbuf;
 
 	/* The peer can send data while we are shutting down this
 	 * subflow at msk destruction time, but we must avoid enqueuing
@@ -796,20 +798,9 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk)
 	if (unlikely(subflow->disposable))
 		return;
 
-	ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
-	sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
-	if (unlikely(ssk_rbuf > sk_rbuf))
-		sk_rbuf = ssk_rbuf;
-
-	/* over limit? can't append more skbs to msk, Also, no need to wake-up*/
-	if (__mptcp_rmem(sk) > sk_rbuf) {
-		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);
-		return;
-	}
-
 	/* Wake-up the reader only for in-sequence data */
 	mptcp_data_lock(sk);
-	if (move_skbs_to_msk(msk, ssk))
+	if (move_skbs_to_msk(mptcp_sk(sk), ssk))
 		sk->sk_data_ready(sk);
 
 	mptcp_data_unlock(sk);
-- 
2.35.3