[ovs-dev] [patch net-next RFC 07/12] dsa: implement ndo_swdev_get_id

Eric W. Biederman ebiederm at xmission.com
Sat Aug 23 11:33:22 UTC 2014


Jiri Pirko <jiri at resnulli.us> writes:

> Thu, Aug 21, 2014 at 06:56:13PM CEST, f.fainelli at gmail.com wrote:
>>2014-08-21 9:19 GMT-07:00 Jiri Pirko <jiri at resnulli.us>:
>>> Signed-off-by: Jiri Pirko <jiri at resnulli.us>
>>> ---
>>>  net/dsa/Kconfig |  2 +-
>>>  net/dsa/slave.c | 16 ++++++++++++++++
>>>  2 files changed, 17 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
>>> index f5eede1..66c445a 100644
>>> --- a/net/dsa/Kconfig
>>> +++ b/net/dsa/Kconfig
>>> @@ -1,6 +1,6 @@
>>>  config HAVE_NET_DSA
>>>         def_bool y
>>> -       depends on NETDEVICES && !S390
>>> +       depends on NETDEVICES && NET_SWITCHDEV && !S390
>>>
>>>  # Drivers must select NET_DSA and the appropriate tagging format
>>>
>>> diff --git a/net/dsa/slave.c b/net/dsa/slave.c
>>> index 45a1e34..e069ba3 100644
>>> --- a/net/dsa/slave.c
>>> +++ b/net/dsa/slave.c
>>> @@ -171,6 +171,19 @@ static int dsa_slave_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
>>>         return -EOPNOTSUPP;
>>>  }
>>>
>>> +static int dsa_slave_swdev_get_id(struct net_device *dev,
>>> +                                 struct netdev_phys_item_id *psid)
>>> +{
>>> +       struct dsa_slave_priv *p = netdev_priv(dev);
>>> +       struct dsa_switch *ds = p->parent;
>>> +       u64 tmp = (u64) ds;
>>> +
>>> +       /* TODO: add more sophisticated id generation */
>>> +       memcpy(&psid->id, &tmp, sizeof(tmp));
>>> +       psid->id_len = sizeof(tmp);
>>
>>There is already an unique id generated, which is the index in the
>>switch tree, and which is stored in struct dsa_switch, so this could
>>probably be simplified to:
>>
>>psid->id = ds->index
>
> That index is 0..n if I understand that correctly. That is not enough.
> The point is to have unique id for every chip in the system. If we would
> have 0,1,2... the collision is very likely.

I am just kibitzing but ethernet switches capable of speaking stp
require a mac address per port.  So if you want a unique id I would
pick one of your mac addresses, which should be uniuqe.

I can understand low end devices where sophisticated things will never
happen fudging on the mac address requirements but by the time you care
I expect you have a mac address.

Eric



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