On Wed, Oct 9, 2013 at 11:07 PM, Pravin Shelar <pshe...@nicira.com> wrote:
> On Wed, Oct 9, 2013 at 9:11 PM, Alexei Starovoitov <a...@plumgrid.com> wrote:
>> On Wed, Oct 9, 2013 at 8:02 PM, Pravin Shelar <pshe...@nicira.com> wrote:
>>> On Tue, Oct 8, 2013 at 8:07 PM, Alexei Starovoitov <a...@plumgrid.com>
>>> wrote:
>>>> The combination of two commits
>>>>
>>>> commit 8e4e1713e4
>>>> ("openvswitch: Simplify datapath locking.")
>>>>
>>>> and
>>>>
>>>> commit 2537b4dd0a
>>>> ("openvswitch:: link upper device for port devices")
>>>>
>>>> introduced a bug where upper_dev wasn't unlinked upon
>>>> netdev_unregister notification
>>>>
>>>> The following steps:
>>>>
>>>> modprobe openvswitch
>>>> ovs-dpctl add-dp test
>>>> ip tuntap add dev tap1 mode tap
>>>> ovs-dpctl add-if test tap1
>>>> ip tuntap del dev tap1 mode tap
>>>>
>>>> are causing multiple warnings:
>>>> diff --git a/net/openvswitch/dp_notify.c b/net/openvswitch/dp_notify.c
>>>> index c323567..e9380bd 100644
>>>> --- a/net/openvswitch/dp_notify.c
>>>> +++ b/net/openvswitch/dp_notify.c
>>>> @@ -88,6 +88,11 @@ static int dp_device_event(struct notifier_block
>>>> *unused, unsigned long event,
>>>> return NOTIFY_DONE;
>>>>
>>>> if (event == NETDEV_UNREGISTER) {
>>>> + /* rx_handler_unregister and upper_dev_unlink immediately
>>>> */
>>>> + if (dev->reg_state == NETREG_UNREGISTERING)
>>>> + ovs_netdev_unlink_dev(vport);
>>>> +
>>>
>>> Rather than doing vport destroy here, we can just unlink upper device
>>> and let workq do rest of work.
>>
>> isn't it what it's doing?
>
> I meant just call netdev_upper_dev_unlink() here in event handler and
> rest of vport destroy can be done in workq.
netdev_upper_dev_unlink() without netdev_rx_handler_unregister() ?!
that's dangerous.
If that is acceptable, then there was no reason to link them in the first place.
notifier asks to unregister. imo the only acceptable deferred task
here is to delay dev_put,
since ovs structures are still referring to it.
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