Re: [PATCH] 9p: disconnect channel when PCI device is removed

[Sasha Levin <levinsasha928@gmail.com>]

On Sun, Apr 15, 2012 at 2:27 PM, Aneesh Kumar K.V
<aneesh.kumar@linux.vnet.ibm.com> wrote:
> Sasha Levin <levinsasha928@gmail.com> writes:
>
>> When a virtio_9p pci device is being removed, we should close down any
>> active channels and free up resources, we're not supposed to BUG() if there's
>> still an open channel since it's a valid case when removing the PCI device.
>>
>> Otherwise, removing the PCI device with an open channel would cause the
>> following BUG():
>>
> ...
>
>> diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
>> index 3d43206..5af18d1 100644
>> --- a/net/9p/trans_virtio.c
>> +++ b/net/9p/trans_virtio.c
>> @@ -615,7 +615,8 @@ static void p9_virtio_remove(struct virtio_device *vdev)
>>  {
>>       struct virtio_chan *chan = vdev->priv;
>>
>> -     BUG_ON(chan->inuse);
>> +     if (chan->inuse)
>> +             p9_virtio_close(chan->client);
>>       vdev->config->del_vqs(vdev);
>>
>>       mutex_lock(&virtio_9p_lock);
>
> But an umount should have resulted in p9_virtio_close ? How are you
> removing the device ? Are you removing the device with file system
> mounted  ?. In that case may be we should return EBUSY ?

I signal the underlying PCI device to remove (echo 1 >
/sys/devices/pci0000\:00/[...]/remove), we can't really prevent that
thing so we must clean up ourselves.