Re: [PATCH v2] staging: bcm2835-audio: Release resources on module_exit()

[Kirill Marinushkin]

On 03/21/18 16:03, Andy Shevchenko wrote:
> On Thu, Mar 15, 2018 at 7:57 AM, Kirill Marinushkin
> <k.marinushkin@xxxxxxxxx> wrote:
>> On 03/13/18 22:23, Andy Shevchenko wrote:
>>> On Tue, Mar 13, 2018 at 9:34 PM, Kirill Marinushkin
>>> <k.marinushkin@xxxxxxxxx> wrote:
>>>> In the current implementation, `rmmod snd_bcm2835` does not release
>>>> resources properly. It causes an oops when trying to list sound devices.
>>>>
>>>> This commit fixes it.
>>> Nice catch!
>>>
>>> See my comments below.
>>>
>>>>  static void snd_devm_unregister_child(struct device *dev, void *res)
>>>>  {
>>>>         struct device *childdev = *(struct device **)res;
>>>> +       struct bcm2835_chip *chip = dev_get_drvdata(childdev);
>>>> +       struct snd_card *card = chip->card;
>>>> +
>>>> +       snd_card_free(card);
>>>> +       dev_set_drvdata(childdev, NULL);
>>> AFAIU this is done by device core.
>> Maybe you are right. But I don't know, which function in the device core does it.
>> It is safe to have this line. So, I suggest to keep it.
> Please, remove.
> If you don't know, perhaps you need to spend more time on doing homework?

You are right, I actually should pay more attention to this detail.
I will remove this line and send as a patch v3

> % git grep -n -w dev_set_drvdata -- drivers/base/dd.c
> drivers/base/dd.c:469:          dev_set_drvdata(dev, NULL);
> drivers/base/dd.c:499:  dev_set_drvdata(dev, NULL);
> drivers/base/dd.c:902:          dev_set_drvdata(dev, NULL);
>
> Last one is the point of your interest.
>