Re: [dpdk-dev] [PATCH v3 2/4] net/af_xdp: specify minimal and maximal MTU

[Ye Xiaolong <xiaolong.ye@intel.com>]

On 04/17, David Marchand wrote:
>On Wed, Apr 17, 2019 at 11:02 AM Xiaolong Ye <xiaolong.ye@intel.com> wrote:
>
>> Since AF_XDP pmd doesn't support multi segment, we need to add a valid
>> check in eth_dev_mtu_set.
>>
>
>How about:
>Properly report mtu capability in port device info.

Sounds better.

>
>
>Reported-by: David Marchand <david.marchand@redhat.com>
>
>Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
>> ---
>>  drivers/net/af_xdp/rte_eth_af_xdp.c | 12 ++++++++++++
>>  1 file changed, 12 insertions(+)
>>
>> diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c
>> b/drivers/net/af_xdp/rte_eth_af_xdp.c
>> index 5cc643ce2..8430921af 100644
>> --- a/drivers/net/af_xdp/rte_eth_af_xdp.c
>> +++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
>> @@ -351,6 +351,9 @@ eth_dev_info(struct rte_eth_dev *dev, struct
>> rte_eth_dev_info *dev_info)
>>         dev_info->max_rx_queues = 1;
>>         dev_info->max_tx_queues = 1;
>>
>> +       dev_info->min_mtu = ETHER_MIN_MTU;
>> +       dev_info->max_mtu = ETH_AF_XDP_FRAME_SIZE -
>> ETH_AF_XDP_DATA_HEADROOM;
>> +
>>
>        dev_info->default_rxportconf.nb_queues = 1;
>>         dev_info->default_txportconf.nb_queues = 1;
>>         dev_info->default_rxportconf.ring_size = ETH_AF_XDP_DFLT_NUM_DESCS;
>> @@ -654,6 +657,15 @@ eth_dev_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
>>         int ret;
>>         int s;
>>
>> +       if (mtu > ETH_AF_XDP_FRAME_SIZE - ETH_AF_XDP_DATA_HEADROOM ||
>> +                       mtu < ETHER_MIN_MTU) {
>> +               AF_XDP_LOG(ERR, "Unsupported MTU of %d. "
>> +                       "max mtu: %d, min mtu: %d", mtu,
>> +                       ETH_AF_XDP_FRAME_SIZE - ETH_AF_XDP_DATA_HEADROOM,
>> +                       ETHER_MIN_MTU);
>> +               return -EINVAL;
>> +       }
>> +
>>
>
>Sorry, I suppose my previous mail was confusing.
>If you provide min/max_mtu, ethdev will enforce those checks for you and
>you don't need to care about it.
>
>See:
>https://git.dpdk.org/dpdk/tree/lib/librte_ethdev/rte_ethdev.c?h=v19.05-rc1#n2630
>
>With this block removed, you can add my review tag.

Got it, will remove it in next version.

Thanks,
Xiaolong
>
>Thanks.
>
>-- 
>David Marchand