Re: [dpdk-dev] [PATCH v5 5/6] ethdev: unify MTU checks

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> Both 'rte_eth_dev_configure()' & 'rte_eth_dev_set_mtu()' sets MTU but
> have slightly different checks. Like one checks min MTU against
> RTE_ETHER_MIN_MTU and other RTE_ETHER_MIN_LEN.
>
> Checks moved into common function to unify the checks. Also this has
> benefit to have common error logs.
>
> Suggested-by: Huisong Li <lihuisong@huawei.com>
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
>  lib/ethdev/rte_ethdev.c | 82 ++++++++++++++++++++++++++---------------
>  lib/ethdev/rte_ethdev.h |  2 +-
>  2 files changed, 54 insertions(+), 30 deletions(-)
>
> diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
> index c2b624aba1a0..0a6e952722ae 100644
> --- a/lib/ethdev/rte_ethdev.c
> +++ b/lib/ethdev/rte_ethdev.c
> @@ -1336,6 +1336,47 @@ eth_dev_get_overhead_len(uint32_t max_rx_pktlen, uint16_t max_mtu)
>       return overhead_len;
>  }
>
> +/* rte_eth_dev_info_get() should be called prior to this function */
> +static int
> +eth_dev_validate_mtu(uint16_t port_id, struct rte_eth_dev_info *dev_info,
> +             uint16_t mtu)
> +{
> +     uint16_t overhead_len;

Again, I would just always use 32-bit arithmetic - safe and easy.
Apart from that:
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

> +     uint32_t frame_size;
> +
> +     if (mtu < dev_info->min_mtu) {
> +             RTE_ETHDEV_LOG(ERR,
> +                     "MTU (%u) < device min MTU (%u) for port_id %u\n",
> +                     mtu, dev_info->min_mtu, port_id);
> +             return -EINVAL;
> +     }
> +     if (mtu > dev_info->max_mtu) {
> +             RTE_ETHDEV_LOG(ERR,
> +                     "MTU (%u) > device max MTU (%u) for port_id %u\n",
> +                     mtu, dev_info->max_mtu, port_id);
> +             return -EINVAL;
> +     }
> +
> +     overhead_len = eth_dev_get_overhead_len(dev_info->max_rx_pktlen,
> +                     dev_info->max_mtu);
> +     frame_size = mtu + overhead_len;
> +     if (frame_size < RTE_ETHER_MIN_LEN) {
> +             RTE_ETHDEV_LOG(ERR,
> +                     "Frame size (%u) < min frame size (%u) for port_id %u\n",
> +                     frame_size, RTE_ETHER_MIN_LEN, port_id);
> +             return -EINVAL;
> +     }
> +
> +     if (frame_size > dev_info->max_rx_pktlen) {
> +             RTE_ETHDEV_LOG(ERR,
> +                     "Frame size (%u) > device max frame size (%u) for port_id %u\n",
> +                     frame_size, dev_info->max_rx_pktlen, port_id);
> +             return -EINVAL;
> +     }
> +
> +     return 0;
> +}
> +
>  int
>  rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
>                     const struct rte_eth_conf *dev_conf)
> @@ -1463,26 +1504,13 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
>               goto rollback;
>       }
>
> -     /*
> -      * Check that the maximum RX packet length is supported by the
> -      * configured device.
> -      */
>       if (dev_conf->rxmode.mtu == 0)
>               dev->data->dev_conf.rxmode.mtu = RTE_ETHER_MTU;
> -     max_rx_pktlen = dev->data->dev_conf.rxmode.mtu + overhead_len;
> -     if (max_rx_pktlen > dev_info.max_rx_pktlen) {
> -             RTE_ETHDEV_LOG(ERR,
> -                     "Ethdev port_id=%u max_rx_pktlen %u > max valid value %u\n",
> -                     port_id, max_rx_pktlen, dev_info.max_rx_pktlen);
> -             ret = -EINVAL;
> -             goto rollback;
> -     } else if (max_rx_pktlen < RTE_ETHER_MIN_LEN) {
> -             RTE_ETHDEV_LOG(ERR,
> -                     "Ethdev port_id=%u max_rx_pktlen %u < min valid value %u\n",
> -                     port_id, max_rx_pktlen, RTE_ETHER_MIN_LEN);
> -             ret = -EINVAL;
> +
> +     ret = eth_dev_validate_mtu(port_id, &dev_info,
> +                     dev->data->dev_conf.rxmode.mtu);
> +     if (ret != 0)
>               goto rollback;
> -     }
>
>       dev->data->mtu = dev->data->dev_conf.rxmode.mtu;
>
> @@ -1491,6 +1519,9 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
>        * size is supported by the configured device.
>        */
>       if (dev_conf->rxmode.offloads & DEV_RX_OFFLOAD_TCP_LRO) {
> +             overhead_len = eth_dev_get_overhead_len(dev_info.max_rx_pktlen,
> +                             dev_info.max_mtu);
> +             max_rx_pktlen = dev->data->dev_conf.rxmode.mtu + overhead_len;
>               if (dev_conf->rxmode.max_lro_pkt_size == 0)
>                       dev->data->dev_conf.rxmode.max_lro_pkt_size = max_rx_pktlen;
>               ret = eth_dev_check_lro_pkt_size(port_id,
> @@ -3437,7 +3468,8 @@ rte_eth_dev_info_get(uint16_t port_id, struct rte_eth_dev_info *dev_info)
>       dev_info->rx_desc_lim = lim;
>       dev_info->tx_desc_lim = lim;
>       dev_info->device = dev->device;
> -     dev_info->min_mtu = RTE_ETHER_MIN_MTU;
> +     dev_info->min_mtu = RTE_ETHER_MIN_LEN - RTE_ETHER_HDR_LEN -
> +             RTE_ETHER_CRC_LEN;
>       dev_info->max_mtu = UINT16_MAX;
>
>       RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_infos_get, -ENOTSUP);
> @@ -3643,21 +3675,13 @@ rte_eth_dev_set_mtu(uint16_t port_id, uint16_t mtu)
>        * which relies on dev->dev_ops->dev_infos_get.
>        */
>       if (*dev->dev_ops->dev_infos_get != NULL) {
> -             uint16_t overhead_len;
> -             uint32_t frame_size;
> -
>               ret = rte_eth_dev_info_get(port_id, &dev_info);
>               if (ret != 0)
>                       return ret;
>
> -             if (mtu < dev_info.min_mtu || mtu > dev_info.max_mtu)
> -                     return -EINVAL;
> -
> -             overhead_len = eth_dev_get_overhead_len(dev_info.max_rx_pktlen,
> -                             dev_info.max_mtu);
> -             frame_size = mtu + overhead_len;
> -             if (mtu < RTE_ETHER_MIN_MTU || frame_size > dev_info.max_rx_pktlen)
> -                     return -EINVAL;
> +             ret = eth_dev_validate_mtu(port_id, &dev_info, mtu);
> +             if (ret != 0)
> +                     return ret;
>       }
>
>       ret = (*dev->dev_ops->mtu_set)(dev, mtu);
> diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
> index 4d0f956a4b28..50e124ff631f 100644
> --- a/lib/ethdev/rte_ethdev.h
> +++ b/lib/ethdev/rte_ethdev.h
> @@ -3056,7 +3056,7 @@ int rte_eth_macaddr_get(uint16_t port_id, struct rte_ether_addr *mac_addr);
>   *  };
>   *
>   * device = dev->device
> - * min_mtu = RTE_ETHER_MIN_MTU
> + * min_mtu = RTE_ETHER_MIN_LEN - RTE_ETHER_HDR_LEN - RTE_ETHER_CRC_LEN
>   * max_mtu = UINT16_MAX
>   *
>   * The following fields will be populated if support for dev_infos_get()
> --
> 2.31.1