Re: [PATCH] [media] v4l2-async: Always unregister the subdev on failure

Hans Verkuil
2016-07-01T11:56:08Z

On 05/11/2016 06:32 PM, Alban Bedel wrote:
> On Wed, 11 May 2016 12:22:44 -0400
> Javier Martinez Canillas <javier@osg.samsung.com> wrote:
>
>> Hello Alban,
>>
>> On 05/11/2016 11:40 AM, Alban Bedel wrote:
>>> In v4l2_async_test_notify() if the registered_async callback or the
>>> complete notifier returns an error the subdev is not unregistered.
>>> This leave paths where v4l2_async_register_subdev() can fail but
>>> leave the subdev still registered.
>>>
>>> Add the required calls to v4l2_device_unregister_subdev() to plug
>>> these holes.
>>>
>>> Signed-off-by: Alban Bedel <alban.bedel@avionic-design.de>
>>> ---
>>> drivers/media/v4l2-core/v4l2-async.c | 10 ++++++++--
>>> 1 file changed, 8 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
>>> index ceb28d4..43393f8 100644
>>> --- a/drivers/media/v4l2-core/v4l2-async.c
>>> +++ b/drivers/media/v4l2-core/v4l2-async.c
>>> @@ -121,13 +121,19 @@ static int v4l2_async_test_notify(struct v4l2_async_notifier *notifier,
>>>
>>> ret = v4l2_subdev_call(sd, core, registered_async);
>>> if (ret < 0 && ret != -ENOIOCTLCMD) {
>>> + v4l2_device_unregister_subdev(sd);
>>> if (notifier->unbind)
>>> notifier->unbind(notifier, sd, asd);
>>> return ret;
>>> }
>>>
>>> - if (list_empty(&notifier->waiting) && notifier->complete)
>>> - return notifier->complete(notifier);
>>> + if (list_empty(&notifier->waiting) && notifier->complete) {
>>> + ret = notifier->complete(notifier);
>>> + if (ret < 0) {
>>> + v4l2_device_unregister_subdev(sd);
>>
>> Isn't a call to notifier->unbind() missing here as well?
>>
>> Also, I think the error path is becoming too duplicated and complex, so
>> maybe we can have a single error path and use goto labels as is common
>> in Linux? For example something like the following (not tested) can be
>> squashed on top of your change:
>
> Yes, that look better. I'll test it and report tomorrow.

I haven't heard anything back about this. Did you manage to test it?

Regards,

Hans