RDS: TCP: set RDS_FLAG_RETRANSMITTED in cp_retrans list

As noted in rds_recv_incoming() sequence numbers on data packets
can decreas for the failover case, and the Rx path is equipped
to recover from this, if the RDS_FLAG_RETRANSMITTED is set
on the rds header of an incoming message with a suspect sequence
number.

The RDS_FLAG_RETRANSMITTED is predicated on the RDS_FLAG_RETRANSMITTED
flag in the rds_message, so make sure the flag is set on messages
queued for retransmission.

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>

net/rds/tcp_send.c

@@ -100,6 +100,9 @@ int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
 		set_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags);
 		tc->t_last_expected_una = rm->m_ack_seq + 1;
 
+		if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))
+			rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED;
+
 		rdsdebug("rm %p tcp nxt %u ack_seq %llu\n",
 			 rm, rds_tcp_snd_nxt(tc),
 			 (unsigned long long)rm->m_ack_seq);