This patch adds the redundant subflows support, sending all packets
redundantly on all available subflows.

Signed-off-by: Geliang Tang <geliang.tang@suse.com>
---
 net/mptcp/protocol.c | 40 ++++++++++++++++++++++++++++------------
 1 file changed, 28 insertions(+), 12 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 74dc832a9d9d..1105c8ad670f 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1559,6 +1559,7 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags)
 	struct mptcp_data_frag *dfrag;
 	int len, copied = 0;
 	bool call_again;
+	int max = 0;
 
 	while ((dfrag = mptcp_send_head(sk))) {
 		info.sent = dfrag->already_sent;
@@ -1586,18 +1587,25 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags)
 				lock_sock(ssk);
 
 			ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
-			if (ret <= 0) {
+			if (ret <= 0 && !call_again) {
 				mptcp_push_release(ssk, &info);
 				goto out;
 			}
 
-			info.sent += ret;
-			copied += ret;
-			len -= ret;
+			if (ret > max)
+				max = ret;
 
-			mptcp_update_post_push(msk, dfrag, ret);
+			if (!call_again) {
+				info.sent += max;
+				copied += max;
+				len -= max;
+
+				mptcp_update_post_push(msk, dfrag, max);
+				max = 0;
+			}
 		}
-		WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
+		if (!call_again)
+			WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
 	}
 
 	/* at this point we held the socket lock for the last subflow we used */
@@ -1623,6 +1631,7 @@ static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
 	struct sock *xmit_ssk;
 	int len, copied = 0;
 	bool first = true;
+	int max = 0;
 
 	info.flags = 0;
 	while ((dfrag = mptcp_send_head(sk))) {
@@ -1646,17 +1655,24 @@ static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk)
 			}
 
 			ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info);
-			if (ret <= 0)
+			if (ret <= 0 && !call_again)
 				goto out;
 
-			info.sent += ret;
-			copied += ret;
-			len -= ret;
+			if (ret > max)
+				max = ret;
+
 			first = false;
+			if (!call_again) {
+				info.sent += max;
+				copied += max;
+				len -= max;
 
-			mptcp_update_post_push(msk, dfrag, ret);
+				mptcp_update_post_push(msk, dfrag, max);
+				max = 0;
+			}
 		}
-		WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
+		if (!call_again)
+			WRITE_ONCE(msk->first_pending, mptcp_send_next(sk));
 	}
 
 out:
-- 
2.34.1