Re: [PATCH 1/3] iio: core: implement devm_iio_device_alloc/devm_iio_device_free

[Lars-Peter Clausen]

On 07/18/2013 12:19 PM, Oleksandr Kravchenko wrote:
> From: Grygorii Strashko <grygorii.strashko@xxxxxx>
>
> Add a resource managed devm_iio_device_alloc()/devm_iio_device_free()
> to automatically clean up any allocations made by IIO drivers,
> thus leading to simplified IIO drivers code.
>
> In addition, this will allow IIO drivers to use other devm_*() API
> (like devm_request_irq) and don't care about the race between
> iio_device_free() and the release of resources by Device core
> during driver removing.
>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
> [o.v.kravchenko@xxxxxxxxxxxxxxx: fix return value ib devm_iio_device_alloc
> in case if devres_alloc failed, remove unused variable "rc"]
> Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@xxxxxxxxxxxxxxx>
> Tested-by: Oleksandr Kravchenko <o.v.kravchenko@xxxxxxxxxxxxxxx>

Very nice, thanks for taking care of this.

Reviewed-by: Lars-Peter Clausen <lars@xxxxxxxxxx>


> ---
>   drivers/iio/industrialio-core.c |   47 +++++++++++++++++++++++++++++++++++++++
>   include/linux/iio/iio.h         |   25 +++++++++++++++++++++
>   2 files changed, 72 insertions(+)
>
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index e145931..d56d122 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -912,6 +912,53 @@ void iio_device_free(struct iio_dev *dev)
>   }
>   EXPORT_SYMBOL(iio_device_free);
>
> +static void devm_iio_device_release(struct device *dev, void *res)
> +{
> +	iio_device_free(*(struct iio_dev **)res);
> +}
> +
> +static int devm_iio_device_match(struct device *dev, void *res, void *data)
> +{
> +	struct iio_dev **r = res;
> +	if (!r || !*r) {
> +		WARN_ON(!r || !*r);
> +		return 0;
> +	}
> +	return *r == data;
> +}
> +
> +struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
> +{
> +	struct iio_dev **ptr, *iio_dev;
> +
> +	ptr = devres_alloc(devm_iio_device_release, sizeof(*ptr),
> +			   GFP_KERNEL);
> +	if (!ptr)
> +		return NULL;
> +
> +	/* use raw alloc_dr for kmalloc caller tracing */
> +	iio_dev = iio_device_alloc(sizeof_priv);
> +	if (iio_dev) {
> +		*ptr = iio_dev;
> +		devres_add(dev, ptr);
> +	} else {
> +		devres_free(ptr);
> +	}
> +
> +	return iio_dev;
> +}
> +EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
> +
> +void devm_iio_device_free(struct device *dev, struct iio_dev *iio_dev)
> +{
> +	int rc;
> +
> +	rc = devres_release(dev, devm_iio_device_release,
> +			    devm_iio_device_match, iio_dev);
> +	WARN_ON(rc);
> +}
> +EXPORT_SYMBOL_GPL(devm_iio_device_free);
> +
>   /**
>    * iio_chrdev_open() - chrdev file open for buffer access and ioctls
>    **/
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index 8d171f4..f1d99f6 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -532,6 +532,31 @@ static inline struct iio_dev *iio_priv_to_dev(void *priv)
>   void iio_device_free(struct iio_dev *indio_dev);
>
>   /**
> + * devm_iio_device_alloc - Resource-managed iio_device_alloc()
> + * @dev: 		Device to allocate iio_dev for
> + * @sizeof_priv: 	Space to allocate for private structure.
> + *
> + * Managed iio_device_alloc.  iio_dev allocated with this function is
> + * automatically freed on driver detach.
> + *
> + * If an iio_dev allocated with this function needs to be freed separately,
> + * devm_iio_device_free() must be used.
> + *
> + * RETURNS:
> + * Pointer to allocated iio_dev on success, NULL on failure.
> + */
> +struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv);
> +
> +/**
> + * devm_iio_device_free - Resource-managed iio_device_free()
> + * @dev:		Device this iio_dev belongs to
> + * @indio_dev: 		the iio_dev associated with the device
> + *
> + * Free indio_dev allocated with devm_iio_device_alloc().
> + */
> +void devm_iio_device_free(struct device *dev, struct iio_dev *iio_dev);
> +
> +/**
>    * iio_buffer_enabled() - helper function to test if the buffer is enabled
>    * @indio_dev:		IIO device structure for device
>    **/

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