Re:Re: Re: [PATCH] gpio: gpiolib-of: Fix refcount bugs in of_mm_gpiochip_add_data()

["Liang He" <windhl@xxxxxxx>]

At 2022-07-06 19:52:44, "Andy Shevchenko" <andy.shevchenko@xxxxxxxxx> wrote:
>On Wed, Jul 6, 2022 at 3:49 AM Liang He <windhl@xxxxxxx> wrote:
>> At 2022-07-05 23:40:12, "Bartosz Golaszewski" <brgl@xxxxxxxx> wrote:
>> >On Mon, Jul 4, 2022 at 11:13 AM Liang He <windhl@xxxxxxx> wrote:
>
>...
>
>> This patch is based on the fact that there is a call site in function 'qe_add_gpiochips()'
>> of src file 'drivers\soc\fsl\qe\gpio.c'.
>>
>> In that function, of_mm_gpiochip_add_data() is contained in a iteration of for_each_compatible_node(),
>> which will automatically increase and decrease the refcount.
>
>"and decrease"
>
>
>> As there is a new reference escaped into the mm_gc->gc.of_node, we should increase the
>> refcount, otherwise, there may be a premature free as we do not know the existence of
>> the reference in 'mm_gc->gc.of_node'.
>>
>> If my understanding is wrong, please correct me.
>
>Yes, see above.
>
>-- 
>With Best Regards,
>Andy Shevchenko

Hi，Andy,

I think you did not get my point.

The for_each_xxx OF api has decreased the refcount, but 
there is a reference |ESCAPE| out of the local area, so we
need additional refcounting, right?

Thanks,

Liang