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SubjectRe: [PATCH 0/5] Call netif_carrier_off() after register_netdev()
Date
>> Ben Hutchings <bhutchings@solarflare.com> writes:
>>> But if you do it beforehand then it doesn't have the intended effect.
>>> (Supposed to be fixed by 22604c866889c4b2e12b73cbf1683bda1b72a313, which
>>> had to be reverted: c276e098d3ee33059b4a1c747354226cec58487c.)
>>>
>>> So you have to do it after, but without dropping the RTNL lock in
>>> between.
>> So you may want to add something like
>>
>> int register_netdev_carrier_off(struct net_device *dev)
>> {
>> int err;
>>
>> rtnl_lock();
>> err = register_netdevice(dev);
>> if (!err)
>> set_bit(__LINK_STATE_NOCARRIER, &dev->state)
>> rtnl_unlock();
>> return err;
>> }
>>
>>
>> for these drivers?

t looks like this variant is equivalent to the existing code:

netif_carrier_off(dev);
err = register_netdev(dev);
if (err)
goto out;

According to explanation in commit 22604c866889c4b2e12b73cbf1683bda1b72a313,
in this case "this causes these drivers to incorrectly report their
link status as IF_OPER_UNKNOWN which can falsely set the IFF_RUNNING
flag when the interface is first brought up".

As far as I understand, to fix the issue it is required to call
netif_carrier_off() itself:

int register_netdev_carrier_off(struct net_device *dev)
{
int err;

rtnl_lock();
err = register_netdevice(dev);
if (!err)
netif_carrier_off(dev);
rtnl_unlock();
return err;
}

What do you think?


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