[dpdk-dev] [PATCH] ethdev: fix setting of MAC address
Andrew Rybchenko
arybchenko at solarflare.com
Wed Dec 20 11:00:01 CET 2017
On 12/19/2017 12:47 PM, Andrew Rybchenko wrote:
> On 12/19/2017 12:29 PM, Olivier MATZ wrote:
>> Hi,
>>
>> On Mon, Dec 18, 2017 at 02:38:55PM +0300, Andrew Rybchenko wrote:
>>> On 12/18/2017 01:53 PM, Igor Ryzhov wrote:
>>>> On Mon, Dec 18, 2017 at 1:35 PM, Andrew Rybchenko
>>>> <arybchenko at solarflare.com <mailto:arybchenko at solarflare.com>> wrote:
>>>>
>>>> On 12/14/2017 08:15 PM, Olivier Matz wrote:
>>>>
>>>> From: Laurent Hardy <laurent.hardy at 6wind.com
>>>> <mailto:laurent.hardy at 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 at dpdk.org <mailto:stable at dpdk.org>
>>>>
>>>> Signed-off-by: Laurent Hardy <laurent.hardy at 6wind.com
>>>> <mailto:laurent.hardy at 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.
>>>>
>>>>
>>>> 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?
>> Yes, I also have the same feeling.
>>
>>> Current behaviour is convenient. Alternative will require copy of MAC
>>> address
>>> to set in device private data and one more copy in the function to
>>> rollback
>>> in
>>> the case of failure. If there are good reasons to change behaviour,
>>> I don't
>>> mind but PMDs should be reviewed carefully and fixed before the change.
>> Right. The first version of the patch was just a fix of the i40e code,
>> which was of course less risky. But we finally decided to to that way
>> for consistency.
>>
>> I will review the other PMDs and send a v2 that should not break
>> them. If you have any guidelines for net/sfc, they will be welcome :)
>
> We'll send net/sfc patch today/tomorrow to fix it.
Done [1]
[1] http://dpdk.org/ml/archives/dev/2017-December/084526.html
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