Patrick McHardy wrote:
> Pavel Emelianov wrote:
>> Patrick McHardy wrote:
>>
>>> Pavel Emelianov wrote:
>>>
>>>> +static int veth_newlink(struct net_device *dev,
>>>> + struct nlattr *tb[], struct nlattr *data[])
>>>> +{
>>>> + int err;
>>>> + struct net_device *peer;
>>>> + struct veth_priv *priv;
>>>> + char ifname[IFNAMSIZ];
>>>> +
>>>> + /*
>>>> + * prepare the devices info
>>>> + */
>>>> +
>>>> + if (tb[IFLA_ADDRESS] == NULL)
>>>> + random_ether_addr(dev->dev_addr);
>>>> +
>>>> + if (data != NULL && data[VETH_INFO_PEER] != NULL) {
>>>> + err = nla_parse_nested(tb, IFLA_INFO_MAX,
>>>> + data[VETH_INFO_PEER], ifla_policy);
>>>> + if (err < 0)
>>>> + return err;
>>>> + }
>>>
>>> Not having a peer should be an error, no?
>>
>> No. That's the intention - if the user doesn't specify "peer" in the
>> command line then two _identical_ devices are created. Of course, if
>> he specifies one name - there'll be a collision, but one can say
>> "my_own_veth_number_%d" and everything will be ok. Or just use the
>> default name provided. E.g. "ip link add type veth" will send a packet
>> with data[VETH_INFO_PEER} == NULL, but this is OK! User just wants a
>> default tunnel and he will get it :)
>
> I see.
>
>> Does this answer your second comment below?
>
>
> No, to get unique names the sequence has to be:
>
> dev_alloc_name
> register_netdevice
> dev_alloc_name
> register_netdevice
>
> But you have:
>
> dev_alloc_name
> dev_alloc_name (<- might allocate same name as first call)
> register_netdevice
> register_netdevice
Oops :) You're right. That's the problem. I was carried away by
testing the "peer" options and checking for names rather than
"veth%d" to work...
By the way, that will create some problems. You see, your patches
imply that the register_netdevice() will be called at the very end
of the ->newlink callback. Otherwise, the error path of any code
following the registering will have to call unregister_netdevice()
which will BUG() in free_netdev() in rtnl_newlink() - the device
state will be neither UNINITIALIZED nor UNREGISTERED :(
>>>> +static __exit void veth_exit(void)
>>>> +{
>>>> + struct veth_priv *priv, *next;
>>>> +
>>>> + rtnl_lock();
>>>> + __rtnl_link_unregister(&veth_link_ops);
>>>> +
>>>> + list_for_each_entry_safe(priv, next, &veth_list, list)
>>>> + veth_dellink(priv->dev);
>>>> + rtnl_unlock();
>>>
>>> Devices are unregistered automatically through the dellink function,
>>> rtnl_link_unregister(..) is enough.
>>
>> OK. This looks like a minor and not-significant comment, so
>> do I need to resend the patch or David is OK to take it and
>> I will send an incremental one?
>
>
> An incremental patch for this is fine I guess, your code is correct,
> its merely a simplification.
>
Thanks,
Pavel
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
