gpio: gpio-stmpe: fully use convert probe to device-managed

Message ID 20210516061425.8757-1-aardelean@deviqon.com
State New
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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.
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. | #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. | #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. | #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 --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 = {