Re: [PATCH v2] iio: ssp_sensors: simplify cleanup using __free

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 11 Mar 2026 23:11:51 +0530
Sanjay Chitroda <sanjayembeddedse@gmail.com> wrote:

> From: Sanjay Chitroda <sanjayembeddedse@gmail.com>
> 
> Replace manual cleanup logic with __free attribute from cleanup.h. This
> removes explicit kfree() calls and simplifies the error handling paths.
> 
> No functional change intended for kmalloc().
> 
> Signed-off-by: Sanjay Chitroda <sanjayembeddedse@gmail.com
>
I think it is worth noting this is an ancient driver.  I don't mind
clear improvements but I would suggest perhaps looking for more
recent code to see if this sort of cleanup applies.

Jonathan

> ---
> Changes in v2:
> - split series to individual patch
> - address review comment from Andy Shevchenko
> - Link to v1 https://lore.kernel.org/all/20260310200513.2162018-3-sanjayembedded@gmail.com/
> ---
>  drivers/iio/common/ssp_sensors/ssp_spi.c | 14 +++-----------
>  1 file changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/iio/common/ssp_sensors/ssp_spi.c b/drivers/iio/common/ssp_sensors/ssp_spi.c
> index 6c81c0385fb5..4320061475e0 100644
> --- a/drivers/iio/common/ssp_sensors/ssp_spi.c
> +++ b/drivers/iio/common/ssp_sensors/ssp_spi.c
> @@ -331,7 +331,6 @@ static int ssp_parse_dataframe(struct ssp_data *data, char *dataframe, int len)
>  /* threaded irq */
>  int ssp_irq_msg(struct ssp_data *data)
>  {
> -	char *buffer;
>  	u8 msg_type;
>  	int ret;
>  	u16 length, msg_options;
> @@ -375,7 +374,7 @@ int ssp_irq_msg(struct ssp_data *data)
>  			 * but the slave should not send such ones - it is to
>  			 * check but let's handle this
>  			 */
> -			buffer = kmalloc(length, GFP_KERNEL | GFP_DMA);
> +			char *buffer __free(kfree) = kmalloc(length, GFP_KERNEL | GFP_DMA);
>  			if (!buffer) {
>  				ret = -ENOMEM;
>  				goto _unlock;
Read the documentation in cleanup.h and make sure you follow it.

> @@ -386,8 +385,6 @@ int ssp_irq_msg(struct ssp_data *data)
>  			if (ret >= 0)
>  				ret = -EPROTO;
>  
> -			kfree(buffer);
> -
>  			dev_err(SSP_DEV, "No match error %x\n",
>  				msg_options);
>  
> @@ -420,22 +417,17 @@ int ssp_irq_msg(struct ssp_data *data)
>  		mutex_unlock(&data->pending_lock);
>  		break;
>  	case SSP_HUB2AP_WRITE:
> -		buffer = kzalloc(length, GFP_KERNEL | GFP_DMA);
> +		char *buffer __free(kfree) = kzalloc(length, GFP_KERNEL | GFP_DMA);

What scope is this cleaning up at the end of?

>  		if (!buffer)
>  			return -ENOMEM;
>  
>  		ret = spi_read(data->spi, buffer, length);
>  		if (ret < 0) {
>  			dev_err(SSP_DEV, "spi read fail\n");
> -			kfree(buffer);
>  			break;
>  		}
>  
> -		ret = ssp_parse_dataframe(data, buffer, length);
> -
> -		kfree(buffer);
> -		break;
> -
> +		return ssp_parse_dataframe(data, buffer, length);
>  	default:
>  		dev_err(SSP_DEV, "unknown msg type\n");
>  		return -EPROTO;