RDS: TCP: Retransmit half-sent datagrams when switching sockets in rds_tcp_reset_callbacks

When we switch a connection's sockets in rds_tcp_rest_callbacks,
any partially sent datagram must be retransmitted on the new
socket so that the receiver can correctly reassmble the RDS
datagram. Use rds_send_reset() which is designed for this purpose.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rds/send.c b/net/rds/send.c
index c9cdb35..b1962f8 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -99,6 +99,7 @@
 	list_splice_init(&conn->c_retrans, &conn->c_send_queue);
 	spin_unlock_irqrestore(&conn->c_lock, flags);
 }
+EXPORT_SYMBOL_GPL(rds_send_reset);
 
 static int acquire_in_xmit(struct rds_connection *conn)
 {
diff --git a/net/rds/tcp.c b/net/rds/tcp.c
index 8faa0b1..7ab1b41 100644
--- a/net/rds/tcp.c
+++ b/net/rds/tcp.c
@@ -173,6 +173,7 @@
 	release_sock(osock->sk);
 	sock_release(osock);
 newsock:
+	rds_send_reset(conn);
 	lock_sock(sock->sk);
 	write_lock_bh(&sock->sk->sk_callback_lock);
 	tc->t_sock = sock;