linux-kernel - Re: [PATCH v11 4/8] iio: buffer-dmaengine: add dev-managed calls for buffer alloc

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Date:   Sat, 21 Mar 2020 17:22:40 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Alexandru Ardelean <alexandru.ardelean@...log.com>
Cc:     <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <robh+dt@...nel.org>,
        <Laszlo.Nagy@...log.com>, <Andrei.Grozav@...log.com>,
        <Michael.Hennerich@...log.com>, <Istvan.Csomortani@...log.com>,
        <Adrian.Costina@...log.com>, <Dragos.Bogdan@...log.com>
Subject: Re: [PATCH v11 4/8] iio: buffer-dmaengine: add dev-managed calls
 for buffer alloc

On Sat, 21 Mar 2020 10:53:11 +0200
Alexandru Ardelean <alexandru.ardelean@...log.com> wrote:

> Currently, when using a 'iio_dmaengine_buffer_alloc()', an matching call to
> 'iio_dmaengine_buffer_free()' must be made.
> 
> With this change, this can be avoided by using
> 'devm_iio_dmaengine_buffer_alloc()'. The buffer will get free'd via the
> device's devres handling.
> 
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
Applied.

Thanks,

Jonathan

> ---
>  .../buffer/industrialio-buffer-dmaengine.c    | 39 +++++++++++++++++++
>  include/linux/iio/buffer-dmaengine.h          |  3 ++
>  2 files changed, 42 insertions(+)
> 
> diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
> index 94da3b1ca3a2..6dedf12b69a4 100644
> --- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c
> +++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
> @@ -229,6 +229,45 @@ void iio_dmaengine_buffer_free(struct iio_buffer *buffer)
>  }
>  EXPORT_SYMBOL_GPL(iio_dmaengine_buffer_free);
>  
> +static void __devm_iio_dmaengine_buffer_free(struct device *dev, void *res)
> +{
> +	iio_dmaengine_buffer_free(*(struct iio_buffer **)res);
> +}
> +
> +/**
> + * devm_iio_dmaengine_buffer_alloc() - Resource-managed iio_dmaengine_buffer_alloc()
> + * @dev: Parent device for the buffer
> + * @channel: DMA channel name, typically "rx".
> + *
> + * This allocates a new IIO buffer which internally uses the DMAengine framework
> + * to perform its transfers. The parent device will be used to request the DMA
> + * channel.
> + *
> + * The buffer will be automatically de-allocated once the device gets destroyed.
> + */
> +struct iio_buffer *devm_iio_dmaengine_buffer_alloc(struct device *dev,
> +	const char *channel)
> +{
> +	struct iio_buffer **bufferp, *buffer;
> +
> +	bufferp = devres_alloc(__devm_iio_dmaengine_buffer_free,
> +			       sizeof(*bufferp), GFP_KERNEL);
> +	if (!bufferp)
> +		return ERR_PTR(-ENOMEM);
> +
> +	buffer = iio_dmaengine_buffer_alloc(dev, channel);
> +	if (IS_ERR(buffer)) {
> +		devres_free(bufferp);
> +		return buffer;
> +	}
> +
> +	*bufferp = buffer;
> +	devres_add(dev, bufferp);
> +
> +	return buffer;
> +}
> +EXPORT_SYMBOL_GPL(devm_iio_dmaengine_buffer_alloc);
> +
>  MODULE_AUTHOR("Lars-Peter Clausen <lars@...afoo.de>");
>  MODULE_DESCRIPTION("DMA buffer for the IIO framework");
>  MODULE_LICENSE("GPL");
> diff --git a/include/linux/iio/buffer-dmaengine.h b/include/linux/iio/buffer-dmaengine.h
> index b3a57444a886..0e503db71289 100644
> --- a/include/linux/iio/buffer-dmaengine.h
> +++ b/include/linux/iio/buffer-dmaengine.h
> @@ -14,4 +14,7 @@ struct iio_buffer *iio_dmaengine_buffer_alloc(struct device *dev,
>  	const char *channel);
>  void iio_dmaengine_buffer_free(struct iio_buffer *buffer);
>  
> +struct iio_buffer *devm_iio_dmaengine_buffer_alloc(struct device *dev,
> +						   const char *channel);
> +
>  #endif