RDS: Fix out-of-order RDS_CMSG_RDMA_SEND_STATUS

Orabug: 22126982

If the RDS user application requests notification of RDMA send
completions, there is a possibility that RDS_CMSG_RDMA_SEND_STATUS
will be delivered out-of-order.

This can happen if RDS drops sending ACK after it received an explicit
ACK. In this case, the rds message ended up in reverse order in the
list.

Reviewed-by: Håkon Bugge <[email protected]>
Reviewed-by: Knut Omang <[email protected]>
Reviewed-by: Santosh Shilimkar <[email protected]>
Reviewed-by: Ajaykumar Hotchandani <[email protected]>
Signed-off-by: Wei Lin Guay <[email protected]>

Author: Wei Lin Guay

net/rds/send.c

@@ -846,7 +846,7 @@ void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
 		if (!rds_send_is_acked(rm, ack, is_acked))
 			break;
 
-		list_move(&rm->m_conn_item, &list);
+		list_move_tail(&rm->m_conn_item, &list);
 		clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
 	}