Re: [dpdk-dev] [PATCH v2] ethdev: fix one MAC address occupies two index in mac addrs

["lihuisong (C)" <lihuisong@huawei.com>]

在 2021/10/12 15:14, Thomas Monjalon 写道:
> 12/10/2021 04:58, lihuisong (C):
>> 在 2021/10/11 18:35, Thomas Monjalon 写道:
>>> 11/10/2021 11:28, Min Hu (Connor):
>>>> From: Huisong Li <lihuisong@huawei.com>
>>>>
>>>> The dev->data->mac_addrs[0] will be changed to a new MAC address when
>>>> applications modify the default MAC address by
>>>> rte_eth_dev_default_mac_addr_set() API. However, If the new default
>>>> MAC address has been added as a non-default MAC address by
>>>> rte_eth_dev_mac_addr_add() API, the rte_eth_dev_default_mac_addr_set()
>>>> API doesn't remove it from dev->data->mac_addrs[]. As a result, one MAC
>>>> address occupies two index capacities in dev->data->mac_addrs[].
>>>>
>>>> This patch adds the logic of removing MAC addresses for this scenario.
>>>>
>>>> Fixes: 854d8ad4ef68 ("ethdev: add default mac address modifier")
>>>> Cc: stable@dpdk.org
>>>>
>>>> Signed-off-by: Huisong Li <lihuisong@huawei.com>
>>>> Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
>>>> ---
>>>> +	/*
>>>> +	 * If the address has been added as a non-default MAC address by
>>>> +	 * rte_eth_dev_mac_addr_add API, it should be removed from
>>>> +	 * dev->data->mac_addrs[].
>>>> +	 */
>>> This is the definition of mac_addrs:
>>>
>>>       struct rte_ether_addr *mac_addrs;
>>>               /**< Device Ethernet link address.
>>>                *   @see rte_eth_dev_release_port()
>>>                */
>>>
>>> I feel we need to explain there can be multiple addresses,
>>> the first one being the default.
>> Do you mean that the problem mentioned in this patch is not a problem?
> It is not a problem if it is expected,
> but nothing is defined.
>
>> Should we accept this scenario?
> We need to decide what is the correct behaviour.
> I see pros and cons on both sides.
Where's the bright side of this behavior?
>>> Another comment,
>>> If we remove the duplicate, we may have to copy to previous default one
>>> to avoid completely deleting the previous default address.
>> That's not necessary.
>>
>> Because the previous default address has been removed from hardware.
>>
>> After the default MAC address is modified, the previous default one is
>> invalid.
> No you don't get it.
> With the current behaviour, the app could keep all the MAC addresses,
> and copy one as the default while keeping it in the rest of the list.
> You are suggesting a different behaviour where there is no duplicate.

This behavior seems to be contrary to the rte_eth_dev_mac_addr_add() API.

If the pmd does not support the dev_ops->mac_addr_set, the 
rte_eth_dev_mac_addr_add()

is used to set default MAC in ethdev layer. Namely, the 
rte_eth_dev_mac_addr_add() can

be used to set default MAC in the special scenario and add MAC address.

But the API does not allow the rest of the list to be the same as the 
default MAC which

occupies idx 0.


If the app uses the MAC address in dev->data->mac_addrs[] to set the 
default MAC,

the PMD actually has only one entry.  As far as I know, the 
dev->data->mac_addrs[] in

ethdev layer should be consistent with the hardware entry of the PMD.

So I think the behavior referred to in this patch is inappropriate.

>
>>> Not sure what should be the behaviour.
>
>
> .