[PATCH] touchscreen: Introduce the use of the managed version of kzalloc

[PATCH] touchscreen: Introduce the use of the managed version of kzalloc

[Himangi Saraogi]

This patch moves data allocated using kzalloc to managed data allocated
using devm_kzalloc and cleans now unnecessary kfrees in probe and remove
functions. Also data allocated using input_allocate_device is moved to
devm_input_allocate_device and unnecessary labels are removed.

The following Coccinelle semantic patch was used for making the change:

@platform@
identifier p, probefn, removefn;
@@
struct platform_driver p = {
  .probe = probefn,
  .remove = removefn,
};

@prb@
identifier platform.probefn, pdev;
expression e, e1, e2;
@@
probefn(struct platform_device *pdev, ...) {
  <+...
- e = kzalloc(e1, e2)
+ e = devm_kzalloc(&pdev->dev, e1, e2)
  ...
?-kfree(e);
  ...+>
}

@rem depends on prb@
identifier platform.removefn;
expression e;
@@
removefn(...) {
  <...
- kfree(e);
  ...>
}

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
---
 drivers/input/touchscreen/da9034-ts.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/drivers/input/touchscreen/da9034-ts.c b/drivers/input/touchscreen/da9034-ts.c
index 8ccf7bb..ed85744 100644
--- a/drivers/input/touchscreen/da9034-ts.c
+++ b/drivers/input/touchscreen/da9034-ts.c
@@ -303,7 +303,8 @@ static int da9034_touch_probe(struct platform_device *pdev)
 	struct input_dev *input_dev;
 	int ret;
 
-	touch = kzalloc(sizeof(struct da9034_touch), GFP_KERNEL);
+	touch = devm_kzalloc(&pdev->dev, sizeof(struct da9034_touch),
+			     GFP_KERNEL);
 	if (touch == NULL) {
 		dev_err(&pdev->dev, "failed to allocate driver data\n");
 		return -ENOMEM;
@@ -322,11 +323,10 @@ static int da9034_touch_probe(struct platform_device *pdev)
 	INIT_DELAYED_WORK(&touch->tsi_work, da9034_tsi_work);
 	touch->notifier.notifier_call = da9034_touch_notifier;
 
-	input_dev = input_allocate_device();
+	input_dev = devm_input_allocate_device(&pdev->dev);
 	if (!input_dev) {
 		dev_err(&pdev->dev, "failed to allocate input device\n");
-		ret = -ENOMEM;
-		goto err_free_touch;
+		return -ENOMEM;
 	}
 
 	input_dev->name		= pdev->name;
@@ -348,16 +348,10 @@ static int da9034_touch_probe(struct platform_device *pdev)
 
 	ret = input_register_device(input_dev);
 	if (ret)
-		goto err_free_input;
+		return ret;
 
 	platform_set_drvdata(pdev, touch);
 	return 0;
-
-err_free_input:
-	input_free_device(input_dev);
-err_free_touch:
-	kfree(touch);
-	return ret;
 }
 
 static int da9034_touch_remove(struct platform_device *pdev)
@@ -365,7 +359,6 @@ static int da9034_touch_remove(struct platform_device *pdev)
 	struct da9034_touch *touch = platform_get_drvdata(pdev);
 
 	input_unregister_device(touch->input_dev);
-	kfree(touch);
 
 	return 0;
 }
-- 
1.9.1

Re: [PATCH] touchscreen: Introduce the use of the managed version of kzalloc

[Dmitry Torokhov]

Hi Himangi,

On Wed, May 21, 2014 at 08:44:05PM +0530, Himangi Saraogi wrote:
> -	input_dev = input_allocate_device();
> +	input_dev = devm_input_allocate_device(&pdev->dev);

...

> @@ -365,7 +359,6 @@ static int da9034_touch_remove(struct platform_device *pdev)
>  	struct da9034_touch *touch = platform_get_drvdata(pdev);
>  
>  	input_unregister_device(touch->input_dev);

When using managed input devices calling input_unregister_device() is
unnecessary. Whole da9034_touch_remove() can be removed. I fixed it up
locally and applied your patch.

Thanks!

> -	kfree(touch);
>  
>  	return 0;
>  }
> -- 
> 1.9.1
> 

-- 
Dmitry