gpio: gpio-stmpe: fully use convert probe to device-managed
diff mbox series

Message ID 20210516061425.8757-1-aardelean@deviqon.com
State Accepted
Commit 2a9a2ccaab99d6f8bbe92f01839dfd1cd4a33ddf
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Series
  • gpio: gpio-stmpe: fully use convert probe to device-managed
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Commit Message

Alexandru Ardelean May 16, 2021, 6:14 a.m. UTC
The driver doesn't look like it can be built as a kmod, so leaks cannot
happen via a rmmod mechanism.
The remove hook was removed via commit 3b52bb960ec6 ("gpio: stmpe: make
it explicitly non-modular").

The IRQ is registered via devm_request_threaded_irq(), making the driver
only partially device-managed.

In any case all resources should be made device-managed, mostly as a good
practice. That way at least the unwinding on error is happening in reverse
order (as the probe).

This change also removes platform_set_drvdata() since the information is
never retrieved to be used in the driver.

Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
---

I'm not sure if this should be marked with a Fixes tag.
But if so, it should probably be for commit 3b52bb960ec6 (also mentioned in
the comment above).

 drivers/gpio/gpio-stmpe.c | 32 +++++++++++++-------------------
 1 file changed, 13 insertions(+), 19 deletions(-)

Comments

Linus Walleij May 19, 2021, 11:55 p.m. UTC | #1
On Sun, May 16, 2021 at 8:14 AM Alexandru Ardelean
<aardelean@deviqon.com> wrote:

> The driver doesn't look like it can be built as a kmod, so leaks cannot
> happen via a rmmod mechanism.
> The remove hook was removed via commit 3b52bb960ec6 ("gpio: stmpe: make
> it explicitly non-modular").
>
> The IRQ is registered via devm_request_threaded_irq(), making the driver
> only partially device-managed.
>
> In any case all resources should be made device-managed, mostly as a good
> practice. That way at least the unwinding on error is happening in reverse
> order (as the probe).
>
> This change also removes platform_set_drvdata() since the information is
> never retrieved to be used in the driver.
>
> Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>

Nice!
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij
Alexandru Ardelean May 20, 2021, 10:06 a.m. UTC | #2
On Thu, 20 May 2021 at 09:40, Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
>
>
>
> On Sunday, May 16, 2021, Alexandru Ardelean <aardelean@deviqon.com> wrote:
>>
>> The driver doesn't look like it can be built as a kmod, so leaks cannot
>> happen via a rmmod mechanism.
>> The remove hook was removed via commit 3b52bb960ec6 ("gpio: stmpe: make
>> it explicitly non-modular").
>>
>> The IRQ is registered via devm_request_threaded_irq(), making the driver
>> only partially device-managed.
>>
>> In any case all resources should be made device-managed, mostly as a good
>> practice. That way at least the unwinding on error is happening in reverse
>> order (as the probe).
>>
>> This change also removes platform_set_drvdata() since the information is
>> never retrieved to be used in the driver.
>
>
> Any driver can be unbind from device thru sysfs. The exception is when they (device drivers) specifically disable that.

Oh, I see.
Thanks for the info :)

>
>>
>> Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
>> ---
>>
>> I'm not sure if this should be marked with a Fixes tag.
>> But if so, it should probably be for commit 3b52bb960ec6 (also mentioned in
>> the comment above).
>>
>>  drivers/gpio/gpio-stmpe.c | 32 +++++++++++++-------------------
>>  1 file changed, 13 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
>> index b94ef8181428..dd4d58b4ae49 100644
>> --- a/drivers/gpio/gpio-stmpe.c
>> +++ b/drivers/gpio/gpio-stmpe.c
>> @@ -449,6 +449,11 @@ static void stmpe_init_irq_valid_mask(struct gpio_chip *gc,
>>         }
>>  }
>>
>> +static void stmpe_gpio_disable(void *stmpe)
>> +{
>> +       stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
>> +}
>> +
>>  static int stmpe_gpio_probe(struct platform_device *pdev)
>>  {
>>         struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
>> @@ -461,7 +466,7 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
>>                 return -EINVAL;
>>         }
>>
>> -       stmpe_gpio = kzalloc(sizeof(*stmpe_gpio), GFP_KERNEL);
>> +       stmpe_gpio = devm_kzalloc(&pdev->dev, sizeof(*stmpe_gpio), GFP_KERNEL);
>>         if (!stmpe_gpio)
>>                 return -ENOMEM;
>>
>> @@ -489,7 +494,11 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
>>
>>         ret = stmpe_enable(stmpe, STMPE_BLOCK_GPIO);
>>         if (ret)
>> -               goto out_free;
>> +               return ret;
>> +
>> +       ret = devm_add_action_or_reset(&pdev->dev, stmpe_gpio_disable, stmpe);
>> +       if (ret)
>> +               return ret;
>>
>>         if (irq > 0) {
>>                 struct gpio_irq_chip *girq;
>> @@ -499,7 +508,7 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
>>                                 "stmpe-gpio", stmpe_gpio);
>>                 if (ret) {
>>                         dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
>> -                       goto out_disable;
>> +                       return ret;
>>                 }
>>
>>                 girq = &stmpe_gpio->chip.irq;
>> @@ -514,22 +523,7 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
>>                 girq->init_valid_mask = stmpe_init_irq_valid_mask;
>>         }
>>
>> -       ret = gpiochip_add_data(&stmpe_gpio->chip, stmpe_gpio);
>> -       if (ret) {
>> -               dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
>> -               goto out_disable;
>> -       }
>> -
>> -       platform_set_drvdata(pdev, stmpe_gpio);
>> -
>> -       return 0;
>> -
>> -out_disable:
>> -       stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
>> -       gpiochip_remove(&stmpe_gpio->chip);
>> -out_free:
>> -       kfree(stmpe_gpio);
>> -       return ret;
>> +       return devm_gpiochip_add_data(&pdev->dev, &stmpe_gpio->chip, stmpe_gpio);
>>  }
>>
>>  static struct platform_driver stmpe_gpio_driver = {
>> --
>> 2.31.1
>>
>
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
Bartosz Golaszewski May 21, 2021, 12:42 p.m. UTC | #3
On Sun, May 16, 2021 at 8:14 AM Alexandru Ardelean
<aardelean@deviqon.com> wrote:
>
> The driver doesn't look like it can be built as a kmod, so leaks cannot
> happen via a rmmod mechanism.
> The remove hook was removed via commit 3b52bb960ec6 ("gpio: stmpe: make
> it explicitly non-modular").
>
> The IRQ is registered via devm_request_threaded_irq(), making the driver
> only partially device-managed.
>
> In any case all resources should be made device-managed, mostly as a good
> practice. That way at least the unwinding on error is happening in reverse
> order (as the probe).
>
> This change also removes platform_set_drvdata() since the information is
> never retrieved to be used in the driver.
>
> Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>

I applied the patch and tweaked the commit message because as Andy
pointed out - this driver can be unbound over sysfs.

Bart

Patch
diff mbox series

diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
index b94ef8181428..dd4d58b4ae49 100644
--- a/drivers/gpio/gpio-stmpe.c
+++ b/drivers/gpio/gpio-stmpe.c
@@ -449,6 +449,11 @@  static void stmpe_init_irq_valid_mask(struct gpio_chip *gc,
 	}
 }
 
+static void stmpe_gpio_disable(void *stmpe)
+{
+	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
+}
+
 static int stmpe_gpio_probe(struct platform_device *pdev)
 {
 	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
@@ -461,7 +466,7 @@  static int stmpe_gpio_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	stmpe_gpio = kzalloc(sizeof(*stmpe_gpio), GFP_KERNEL);
+	stmpe_gpio = devm_kzalloc(&pdev->dev, sizeof(*stmpe_gpio), GFP_KERNEL);
 	if (!stmpe_gpio)
 		return -ENOMEM;
 
@@ -489,7 +494,11 @@  static int stmpe_gpio_probe(struct platform_device *pdev)
 
 	ret = stmpe_enable(stmpe, STMPE_BLOCK_GPIO);
 	if (ret)
-		goto out_free;
+		return ret;
+
+	ret = devm_add_action_or_reset(&pdev->dev, stmpe_gpio_disable, stmpe);
+	if (ret)
+		return ret;
 
 	if (irq > 0) {
 		struct gpio_irq_chip *girq;
@@ -499,7 +508,7 @@  static int stmpe_gpio_probe(struct platform_device *pdev)
 				"stmpe-gpio", stmpe_gpio);
 		if (ret) {
 			dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
-			goto out_disable;
+			return ret;
 		}
 
 		girq = &stmpe_gpio->chip.irq;
@@ -514,22 +523,7 @@  static int stmpe_gpio_probe(struct platform_device *pdev)
 		girq->init_valid_mask = stmpe_init_irq_valid_mask;
 	}
 
-	ret = gpiochip_add_data(&stmpe_gpio->chip, stmpe_gpio);
-	if (ret) {
-		dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
-		goto out_disable;
-	}
-
-	platform_set_drvdata(pdev, stmpe_gpio);
-
-	return 0;
-
-out_disable:
-	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
-	gpiochip_remove(&stmpe_gpio->chip);
-out_free:
-	kfree(stmpe_gpio);
-	return ret;
+	return devm_gpiochip_add_data(&pdev->dev, &stmpe_gpio->chip, stmpe_gpio);
 }
 
 static struct platform_driver stmpe_gpio_driver = {