From: Geliang Tang <redacted>

This patch implements .splice_read interface of mptcp struct proto_ops
as mptcp_splice_read() with reference to tcp_splice_read().

Corresponding to __tcp_splice_read(), __mptcp_splice_read() is defined,
invoking mptcp_read_sock() instead of tcp_read_sock().

mptcp_splice_read() is almost the same as tcp_splice_read(), except for
sock_rps_record_flow().

Signed-off-by: Geliang Tang <redacted>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/protocol.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index c58e306ec3ef..3aee29f70954 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c

@@ -4396,6 +4396,118 @@ static int mptcp_read_sock(struct sock *sk, read_descriptor_t *desc,
 	return __mptcp_read_sock(sk, desc, recv_actor, false);
 }
 
+static int __mptcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
+{
+	/* Store TCP splice context information in read_descriptor_t. */
+	read_descriptor_t rd_desc = {
+		.arg.data = tss,
+		.count	  = tss->len,
+	};
+
+	return mptcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
+}
+
+/**
+ *  mptcp_splice_read - splice data from MPTCP socket to a pipe
+ * @sock:	socket to splice from
+ * @ppos:	position (not valid)
+ * @pipe:	pipe to splice to
+ * @len:	number of bytes to splice
+ * @flags:	splice modifier flags
+ *
+ * Description:
+ *    Will read pages from given socket and fill them into a pipe.