Re: [dpdk-dev] [PATCH] ethdev: fix setting of MAC address

[Igor Ryzhov <iryzhov@nfware.com>]

Hello Andrew,

Don't you think that it's not correct that net/sfc works that way?

If we go further, dev->dev_ops->mac_addr_set not only should be called
before ether_addr_copy.
It should return status code, and in case of error ether_addr_copy
shouldn't be called at all.
Am I wrong?

Best regards,
Igor

On Mon, Dec 18, 2017 at 1:35 PM, Andrew Rybchenko <arybchenko@solarflare.com
> wrote:

> On 12/14/2017 08:15 PM, Olivier Matz wrote:
>
>> From: Laurent Hardy <laurent.hardy@6wind.com>
>>
>> When a new mac address is set, it is saved in dev->data->mac_addrs
>> before the ethdev handler is called.
>>
>> First, it is inconsistent with the other ethdev functions
>> rte_eth_dev_mac_addr_remove() and rte_eth_dev_mac_addr_add().
>>
>> Moreover, it prevents the drivers from wrongly comparing the old address
>> and the new one, like it's done in i40evf driver:
>>
>>         if (is_same_ether_addr(mac_addr, dev->data->mac_addrs))
>>                 return;
>>
>> Fixes: 943c2d899a0c ("net/i40e: set VF MAC from VF")
>> Fixes: 854d8ad4ef68 ("ethdev: add default mac address modifier")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Laurent Hardy <laurent.hardy@6wind.com>
>> ---
>>   lib/librte_ether/rte_ethdev.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.
>> c
>> index 4f492e3db..297c02a54 100644
>> --- a/lib/librte_ether/rte_ethdev.c
>> +++ b/lib/librte_ether/rte_ethdev.c
>> @@ -2643,11 +2643,11 @@ rte_eth_dev_default_mac_addr_set(uint16_t
>> port_id, struct ether_addr *addr)
>>         dev = &rte_eth_devices[port_id];
>>         RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->mac_addr_set, -ENOTSUP);
>>   +     (*dev->dev_ops->mac_addr_set)(dev, addr);
>> +
>>         /* Update default address in NIC data structure */
>>         ether_addr_copy(addr, &dev->data->mac_addrs[0]);
>>   -     (*dev->dev_ops->mac_addr_set)(dev, addr);
>> -
>>         return 0;
>>   }
>>
>
> NACK, unfortunately it will break net/sfc in one of branches when a new MAC
> is set using restart. It relies on the fact that a new MAC is already
> available in
> device data.
>