linux-kernel - Re: [PATCH] Input: touchscreen : Introduce the use of the managed version of kzalloc

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Message-ID: <20140529071510.GF11817@core.coreip.homeip.net>
Date:	Thu, 29 May 2014 00:15:10 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Himangi Saraogi <himangi774@...il.com>
Cc:	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	julia.lawall@...6.fr
Subject: Re: [PATCH] Input: touchscreen : Introduce the use of the managed
 version of kzalloc

On Wed, May 28, 2014 at 11:32:14PM +0530, Himangi Saraogi wrote:
> This patch moves most data allocated in the probe function from
> unmanaged interfaces to managed interfaces. The kfrees and error
> handling code is done away with. Also, the unnecesary labels are
> removed and the function mrstouch_remove is removed as it becomes
> empty after removing the no longer required function calls. Also,
> linux/device.h include is added to make sure the devm_*() routine
> declarations are unambiguously available.
> 
> The following Coccinelle semantic patch was used for making a part of
> 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@...il.com>
> Acked-by: Julia Lawall <julia.lawall@...6.fr>
> ---
>  drivers/input/touchscreen/intel-mid-touch.c | 39 ++++++++---------------------
>  1 file changed, 11 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/intel-mid-touch.c b/drivers/input/touchscreen/intel-mid-touch.c
> index 4f6b156..b1b1e8b 100644
> --- a/drivers/input/touchscreen/intel-mid-touch.c
> +++ b/drivers/input/touchscreen/intel-mid-touch.c
> @@ -36,6 +36,7 @@
>  #include <linux/irq.h>
>  #include <linux/delay.h>
>  #include <asm/intel_scu_ipc.h>
> +#include <linux/device.h>
>  
>  /* PMIC Interrupt registers */
>  #define PMIC_REG_ID1		0x00 /* PMIC ID1 register */
> @@ -580,12 +581,12 @@ static int mrstouch_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>  
> -	tsdev = kzalloc(sizeof(struct mrstouch_dev), GFP_KERNEL);
> -	input = input_allocate_device();
> +	tsdev = devm_kzalloc(&pdev->dev, sizeof(struct mrstouch_dev),
> +			     GFP_KERNEL);
> +	input = devm_input_allocate_device(&pdev->dev);
>  	if (!tsdev || !input) {
>  		dev_err(&pdev->dev, "unable to allocate memory\n");
> -		err = -ENOMEM;
> -		goto err_free_mem;
> +		return -ENOMEM;
>  	}
>  
>  	tsdev->dev = &pdev->dev;
> @@ -598,7 +599,7 @@ static int mrstouch_probe(struct platform_device *pdev)
>  	err = mrstouch_adc_init(tsdev);
>  	if (err) {
>  		dev_err(&pdev->dev, "ADC initialization failed\n");
> -		goto err_free_mem;
> +		return -ENOMEM;
>  	}
>  
>  	input->name = "mrst_touchscreen";
> @@ -618,39 +619,22 @@ static int mrstouch_probe(struct platform_device *pdev)
>  	input_set_abs_params(tsdev->input, ABS_PRESSURE,
>  			     MRST_PRESSURE_MIN, MRST_PRESSURE_MAX, 0, 0);
>  
> -	err = request_threaded_irq(tsdev->irq, NULL, mrstouch_pendet_irq,
> -				   IRQF_ONESHOT, "mrstouch", tsdev);
> +	err = devm_request_threaded_irq(&pdev->dev, tsdev->irq, NULL,
> +					mrstouch_pendet_irq, IRQF_ONESHOT,
> +					"mrstouch", tsdev);
>  	if (err) {
>  		dev_err(tsdev->dev, "unable to allocate irq\n");
> -		goto err_free_mem;
> +		return -ENOMEM;

This is bad conversion. We used to report 'err' returned by
request_threaded_irq, but now we always report -ENOMEM. I fixed it up
here and in other places and applied.

>  	}
>  
>  	err = input_register_device(tsdev->input);
>  	if (err) {
>  		dev_err(tsdev->dev, "unable to register input device\n");
> -		goto err_free_irq;
> +		return -ENOMEM;
>  	}
>  
>  	platform_set_drvdata(pdev, tsdev);
>  	return 0;
> -
> -err_free_irq:
> -	free_irq(tsdev->irq, tsdev);
> -err_free_mem:
> -	input_free_device(input);
> -	kfree(tsdev);
> -	return err;
> -}
> -
> -static int mrstouch_remove(struct platform_device *pdev)
> -{
> -	struct mrstouch_dev *tsdev = platform_get_drvdata(pdev);
> -
> -	free_irq(tsdev->irq, tsdev);
> -	input_unregister_device(tsdev->input);
> -	kfree(tsdev);
> -
> -	return 0;
>  }
>  
>  static struct platform_driver mrstouch_driver = {
> @@ -659,7 +643,6 @@ static struct platform_driver mrstouch_driver = {
>  		.owner	= THIS_MODULE,
>  	},
>  	.probe		= mrstouch_probe,
> -	.remove		= mrstouch_remove,
>  };
>  module_platform_driver(mrstouch_driver);
>  
> -- 
> 1.9.1
> 

-- 
Dmitry
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