Re: [PATCH net-next 3/6] net: bridge: break if __br_mdb_del fails

From: Vivien Didelot
Date: Thu May 18 2017 - 11:10:51 EST


Hi Nikolay,

Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx> writes:

>> err = __br_mdb_del(br, entry);
>> - if (!err)
>> - __br_mdb_notify(dev, p, entry, RTM_DELMDB);
>> + if (err)
>> + break;
>> + __br_mdb_notify(dev, p, entry, RTM_DELMDB);
>> }
>> } else {
>> err = __br_mdb_del(br, entry);
>>
>
> This can potentially break user-space scripts that rely on the best-effort
> behaviour, this is the normal "delete without vid & enabled vlan filtering".
> You can check the fdb delete code which does the same, this was intentional.
>
> You can add an mdb entry without a vid to all vlans, add a vlan and then try
> to remove it from all vlans where it is present - with this patch obviously
> that will fail at the new vlan.

OK good to know. That intention wasn't obvious. I can make __br_mdb_del
return void instead? What about the rest of the patchset if I do so?

Thanks,

Vivien