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

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Message-ID: <38e4b736-b053-05e0-112b-550411ecb56c@xs4all.nl>
Date:	Fri, 1 Jul 2016 13:55:44 +0200
From:	Hans Verkuil <hverkuil@...all.nl>
To:	Alban Bedel <alban.bedel@...onic-design.de>,
	Javier Martinez Canillas <javier@....samsung.com>
Cc:	linux-media@...r.kernel.org,
	Mauro Carvalho Chehab <mchehab@....samsung.com>,
	Sakari Ailus <sakari.ailus@....fi>,
	Bryan Wu <cooloney@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [media] v4l2-async: Always unregister the subdev on
 failure

On 05/11/2016 06:32 PM, Alban Bedel wrote:
> On Wed, 11 May 2016 12:22:44 -0400
> Javier Martinez Canillas <javier@....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@...onic-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