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Message-ID: <46962AC5.2030005@trash.net>
Date: Thu, 12 Jul 2007 15:21:09 +0200
From: Patrick McHardy <kaber@...sh.net>
To: Pavel Emelianov <xemul@...nvz.org>
CC: David Miller <davem@...emloft.net>,
Linux Netdev List <netdev@...r.kernel.org>
Subject: Re: [PATCH 2/2] Virtual ethernet device driver
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
>>>+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.
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