Re: [PATCH v1 1/1] iio: core: Simplify IIO core managed APIs

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 16 Feb 2026 09:14:12 +0100
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> Use devm_add_action_or_reset() instead of devres_alloc() and
> devres_add(), which works the same. This will simplify the
> code. There is no functional changes.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Nice.  There was a mass sweep up of these cases a few years
back but I guess these instances slipped through the scripting
that was used to find those.

> ---
>  drivers/iio/buffer/kfifo_buf.c     | 29 +++++++++++++----------------
>  drivers/iio/industrialio-trigger.c | 24 ++++++++++--------------
>  2 files changed, 23 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/iio/buffer/kfifo_buf.c b/drivers/iio/buffer/kfifo_buf.c
> index 38034c8bcc04..a126cc05fb38 100644
> --- a/drivers/iio/buffer/kfifo_buf.c
> +++ b/drivers/iio/buffer/kfifo_buf.c
> @@ -234,23 +234,20 @@ static void devm_iio_kfifo_release(struct device *dev, void *res)
>   * @dev:		Device to allocate kfifo buffer for
>   *
>   * RETURNS:
> - * Pointer to allocated iio_buffer on success, NULL on failure.
> + * Pointer to allocated iio_buffer on success, error pointer on failure.

This had me briefly confused as I failed to notice it was static
(no idea why I gave such a simple internal function kernel-doc!)

However that brings the obvious follow up question.  Given your
simplification does having a helper make sense given only a single caller?

Let's just squash it and have the two calls inline + some resulting docs
updates to get rid of the references to this function.

Thanks,

Jonathan


>   */
>  static struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
>  {
> -	struct iio_buffer **ptr, *r;
> -
> -	ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
> -	if (!ptr)
> -		return NULL;
> +	struct iio_buffer *r;
> +	int ret;
>  
>  	r = iio_kfifo_allocate();
> -	if (r) {
> -		*ptr = r;
> -		devres_add(dev, ptr);
> -	} else {
> -		devres_free(ptr);
> -	}
> +	if (!r)
> +		return ERR_PTR(-ENOMEM);
> +
> +	ret = devm_add_action_or_reset(dev, devm_iio_kfifo_release, r);
> +	if (ret)
> +		return ERR_PTR(ret);
>  
>  	return r;
>  }
> @@ -275,8 +272,8 @@ int devm_iio_kfifo_buffer_setup_ext(struct device *dev,
>  	struct iio_buffer *buffer;
>  
>  	buffer = devm_iio_kfifo_allocate(dev);
> -	if (!buffer)
> -		return -ENOMEM;
> +	if (IS_ERR(buffer))
> +		return PTR_ERR(buffer);
>  
>  	indio_dev->modes |= INDIO_BUFFER_SOFTWARE;
>  	indio_dev->setup_ops = setup_ops;