Subject: Re: [PATCH net-next v2 RESEND 1/4] macvlan: support mac address changes when fwd_priv is enable

From: Ding Tianhong <[email-masked]>
Date: Sat, 14 Jun 2014 13:01:05 +0800

On 2014/6/13 21:30, Vlad Yasevich wrote:
> On 06/12/2014 11:10 PM, Ding Tianhong wrote:
>> On 2014/6/12 22:24, Vlad Yasevich wrote:
>>> On 06/11/2014 09:45 PM, Ding Tianhong wrote:
>>>> On 2014/6/10 0:51, Vlad Yasevich wrote:
>>>>> [.. CC John Fastabend <[email-masked]> ]
>>>>>
>>>>> On 06/07/2014 03:45 AM, Ding Tianhong wrote:
>>>>>> If lowerdev supports L2 forwarding offload, the macvlan's hw address
>>>>>> will be set to the rar of the lowerdev and no need to set uc list,
>>>>>> and when the macvlan's hw address changes, the macvlan should remove
>>>>>> the old fwd and rebuild a new fwd for the macvlan.
>>>>>>
>>>>>> Signed-off-by: Ding Tianhong <[email-masked]>
>>>>>> ---
>>>>>>  drivers/net/macvlan.c | 21 +++++++++++++++++++++
>>>>>>  1 file changed, 21 insertions(+)
>>>>>>
>>>>>> diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
>>>>>> index 453d55a..67485ab 100644
>>>>>> --- a/drivers/net/macvlan.c
>>>>>> +++ b/drivers/net/macvlan.c
>>>>>> @@ -523,6 +523,27 @@ static int macvlan_sync_address(struct net_device *dev, unsigned char *addr)
>>>>>>  		if (macvlan_addr_busy(vlan->port, addr))
>>>>>>  			return -EBUSY;
>>>>>>  
>>>>>> +		if (vlan->fwd_priv) {
>>>>>> +			lowerdev->netdev_ops->ndo_dfwd_del_station(lowerdev,
>>>>>> +								   vlan->fwd_priv);
>>>>>> +			vlan->fwd_priv = NULL;
>>>>>> +			ether_addr_copy(dev->perm_addr, dev->dev_addr);
>>>>>> +			ether_addr_copy(dev->dev_addr, addr);
>>>>>> +			vlan->fwd_priv =
>>>>>> +			    lowerdev->netdev_ops->ndo_dfwd_add_station(lowerdev,
>>>>>> +								       dev);
>>>>>> +			/* If we get a NULL pointer back, or if we get an error
>>>>>> +			 * then we should restore the old mac address and fwd.
>>>>>> +			 */
>>>>>> +			if (IS_ERR_OR_NULL(vlan->fwd_priv)) {
>>>>>> +				ether_addr_copy(dev->dev_addr, dev->perm_addr);
>>>>>> +				vlan->fwd_priv =
>>>>>> +				    lowerdev->netdev_ops->ndo_dfwd_add_station(lowerdev,
>>>>>> +									       dev);
>>>>>> +				return -EINVAL;
>>>>>> +			}
>>>>>> +			return 0;
>>>>>> +		}
>>>>>
>>>>> Calling del_stations add_station causes all sorts of VMDQ/ring
>>>>> operations to happen...  Not sure if we can do that while we have a live
>>>>> macvlan/macvtap that is capable of transmitting data.
>>>>>
>>>>> Wouldn't it be sufficient to have a call to call to update with mac
>>>>> filter with the appropriate VMDQ.
>>>>>
>>>>> John, I defer to you here.  The above looks really heavy-weight and
>>>>> I am not sure if its correct.
>>>>>
>>>>> Thanks
>>>>> -vlad
>>>>
>>>> I have used two 82599 nic to test this problem, I modify the ixgbe drivers and set the  L2 forwarding offload default,
>>>> without this patch, when I change the macvlan mac address, the kernel oops, and if I apply this patch, the ixgbe could
>>>> work well with the maclvan, so I don't think this solution has problem.
>>>
>>> Have you tried changing the address while at the same time
>>> transmitting data through the macvlan?
>>>
>>> -vlad
>>>
>>
>> Yes, I tried, the lowerdev will be closed when calling ixgbe_fwd_del, then the transmitting was broken and about 1 second later,
>> the transmitting restored and start to work again.
>>
>> 64 bytes from 192.168.10.8: icmp_seq=14 ttl=64 time=0.109 ms
>> 64 bytes from 192.168.10.8: icmp_seq=15 ttl=64 time=0.112 ms
>> ping: sendmsg: Network is down
>> 64 bytes from 192.168.10.8: icmp_seq=17 ttl=64 time=1000 ms
>> 64 bytes from 192.168.10.8: icmp_seq=18 ttl=64 time=0.147 ms
>>
> 
> Right.  This is what I figured would happen and doesn't happen
> with any other device when changing the mac address.
> 
> If this behavior is OK with other folks, I'll shut up, but IMO
> we shouldn't just correctly update the mac filter and leave the
> VMDQs alone.
> 
> -vlad
> 

Yes, according to your important suggestion, we could further analysis this problem,
and can you explain more about how to fix it better, just like the VMDQ, I am not very
clear about this, thanks for any feedback.

Regards
Ding 

>> Ding
>>
>>>>
>>>> Thanks
>>>> Ding
>>>>
>>>>>
>>>>>>  		if (!vlan->port->passthru) {
>>>>>>  			err = dev_uc_add(lowerdev, addr);
>>>>>>  			if (err)
>>>>>>
>>>>>
>>>>>
>>>>> .
>>>>>
>>>>
>>>>
>>>
>>>
>>> .
>>>
>>
>>
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> 
> 
> .
>