linux-kernel - Re: [PATCH] regulator: core: fix error path of regulator_ena_gpio

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Message-ID: <56CD71DF.8020509@nvidia.com>
Date:	Wed, 24 Feb 2016 09:03:27 +0000
From:	Jon Hunter <jonathanh@...dia.com>
To:	Krzysztof Adamski <krzysztof.adamski@...to.com>
CC:	Mark Brown <broonie@...nel.org>,
	"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] regulator: core: fix error path of
 regulator_ena_gpio_free


On 24/02/16 08:26, Krzysztof Adamski wrote:
> On Tue, Feb 23, 2016 at 03:18:59PM +0000, Jon Hunter wrote:
>>
>> On 23/02/16 14:47, Krzysztof Adamski wrote:
>>> Signed-off-by: Krzysztof Adamski <krzysztof.adamski@...to.com>
>>> Reported-by: Jon Hunter <jonathanh@...dia.com>
>>
>> Nit ... I think that order of the above should be reversed.
>>
> 
> Couldn't find any reference stating proper order of those tags and
> briefly looking at other commit messages shows this order as quite common.
> 
>>> ---
>>>  drivers/regulator/core.c | 8 +++-----
>>>  1 file changed, 3 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
>>> index 6ee9ba4..d1e7859 100644
>>> --- a/drivers/regulator/core.c
>>> +++ b/drivers/regulator/core.c
>>> @@ -3919,7 +3919,7 @@ regulator_register(const struct regulator_desc
>>> *regulator_desc,
>>>          if (ret != 0) {
>>>              rdev_err(rdev, "Failed to request enable GPIO%d: %d\n",
>>>                   config->ena_gpio, ret);
>>> -            goto wash;
>>> +            goto clean;
>>>          }
>>>      }
>>>
>>> @@ -3942,7 +3942,7 @@ regulator_register(const struct regulator_desc
>>> *regulator_desc,
>>>
>>>      ret = set_machine_constraints(rdev, constraints);
>>>      if (ret < 0)
>>> -        goto scrub;
>>> +        goto wash;
>>>
>>>      if (init_data && init_data->supply_regulator)
>>>          rdev->supply_name = init_data->supply_regulator;
>>> @@ -3972,10 +3972,8 @@ out:
>>>  unset_supplies:
>>>      unset_regulator_supplies(rdev);
>>>
>>> -scrub:
>>> -    regulator_ena_gpio_free(rdev);
>>> -
>>>  wash:
>>> +    regulator_ena_gpio_free(rdev);
>>>      device_unregister(&rdev->dev);
>>>      /* device core frees rdev */
>>>      rdev = ERR_PTR(ret);
>>
>> What about the case where device_register() fails? I think you still
>> call clean and so you will leak the gpio?
>>
>> Jon
>>
> True. I couldn't find anything more clever than calling
> regulator_ena_gpio_free() in two paths like in an upcomming v2. Putting
> it inside of regulator_dev_release() won't entirely fix the problem
> either as this won't be called in this particular case
> (device_register() fail). I personally still prefer calling
> regulator_ena_gpio_free() inside of regulator_register insted of
> deffering it to regulator_dev_release() as it seems to be clearer to me.

Yes if you were to put regulator_ena_gpio_free() inside the
regulator_dev_release(), you would still need to call
regulator_ena_gpio_free() if the device_register fails. I see the way
you have it now there are two places you call regulator_ena_gpio_free()
in the error path. It is not a big deal, really either way.

Jon