-* ethdev: ``uint32_t max_rx_pkt_len`` field of ``struct rte_eth_rxmode``, will be
- replaced by a new ``uint32_t mtu`` field of ``struct rte_eth_conf`` in v21.11.
- The new ``mtu`` field will be used to configure the initial device MTU via
- ``rte_eth_dev_configure()`` API.
- Later MTU can be changed by ``rte_eth_dev_set_mtu()`` API as done now.
- The existing ``(struct rte_eth_dev)->data->mtu`` variable will be used to store
- the configured ``mtu`` value,
- and this new ``(struct rte_eth_dev)->data->dev_conf.mtu`` variable will
- be used to store the user configuration request.
- Unlike ``max_rx_pkt_len``, which was valid only when ``JUMBO_FRAME`` enabled,
- ``mtu`` field will be always valid.
- When ``mtu`` config is not provided by the application, default ``RTE_ETHER_MTU``
- value will be used.
- ``(struct rte_eth_dev)->data->mtu`` should be updated after MTU set successfully,
- either by ``rte_eth_dev_configure()`` or ``rte_eth_dev_set_mtu()``.
-
- An application may need to configure device for a specific Rx packet size, like for
- cases ``DEV_RX_OFFLOAD_SCATTER`` is not supported and device received packet size
- can't be bigger than Rx buffer size.
- To cover these cases an application needs to know the device packet overhead to be
- able to calculate the ``mtu`` corresponding to a Rx buffer size, for this
- ``(struct rte_eth_dev_info).max_rx_pktlen`` will be kept,
- the device packet overhead can be calculated as:
- ``(struct rte_eth_dev_info).max_rx_pktlen - (struct rte_eth_dev_info).max_mtu``
-