[PATCH 1/2] iio: inkern: add error case in iio_channel_get()

[PATCH 1/2] iio: inkern: add error case in iio_channel_get()

[Kim, Milo]

 The datasheet name is defined in the IIO driver.
 On the other hand, the adc_channel_label is configured in
 the platform side.
 If the datasheet name is not matched with any adc_channel_label,
 the iio_channel_get() should be returned as error for preventing
 invalid channel data access.

 This can be handled either way.
 (a) checking null data when using it : in the xxx_read_raw()
 or
 (b) error returns when the channel is requested : this patch

 The IIO consumer can't use the channel with invalid channel spec.
 Therefore case (b) is more reasonable.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
---
 drivers/iio/inkern.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index 1faa240..13748c0 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -136,12 +136,21 @@ struct iio_channel *iio_channel_get(const char *name, const char *channel_name)
 
 	channel->indio_dev = c->indio_dev;
 
-	if (c->map->adc_channel_label)
+	if (c->map->adc_channel_label) {
 		channel->channel =
 			iio_chan_spec_from_name(channel->indio_dev,
 						c->map->adc_channel_label);
 
+		if (channel->channel == NULL)
+			goto error_no_chan;
+	}
+
 	return channel;
+
+error_no_chan:
+	iio_device_put(c->indio_dev);
+	kfree(channel);
+	return ERR_PTR(-EINVAL);
 }
 EXPORT_SYMBOL_GPL(iio_channel_get);
 
-- 
1.7.9.5


Best Regards,
Milo

Re: [PATCH 1/2] iio: inkern: add error case in iio_channel_get()

[Jonathan Cameron]

On 09/17/2012 09:44 AM, Kim, Milo wrote:
>  The datasheet name is defined in the IIO driver.
>  On the other hand, the adc_channel_label is configured in
>  the platform side.
>  If the datasheet name is not matched with any adc_channel_label,
>  the iio_channel_get() should be returned as error for preventing
>  invalid channel data access.
> 
>  This can be handled either way.
>  (a) checking null data when using it : in the xxx_read_raw()
>  or
>  (b) error returns when the channel is requested : this patch
> 
>  The IIO consumer can't use the channel with invalid channel spec.
>  Therefore case (b) is more reasonable.
> 
Nicely patch, thanks.

Merged to togreg branch of
git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git


> Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
> ---
>  drivers/iio/inkern.c |   11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
> index 1faa240..13748c0 100644
> --- a/drivers/iio/inkern.c
> +++ b/drivers/iio/inkern.c
> @@ -136,12 +136,21 @@ struct iio_channel *iio_channel_get(const char *name, const char *channel_name)
>  
>  	channel->indio_dev = c->indio_dev;
>  
> -	if (c->map->adc_channel_label)
> +	if (c->map->adc_channel_label) {
>  		channel->channel =
>  			iio_chan_spec_from_name(channel->indio_dev,
>  						c->map->adc_channel_label);
>  
> +		if (channel->channel == NULL)
> +			goto error_no_chan;
> +	}
> +
>  	return channel;
> +
> +error_no_chan:
> +	iio_device_put(c->indio_dev);
> +	kfree(channel);
> +	return ERR_PTR(-EINVAL);
>  }
>  EXPORT_SYMBOL_GPL(iio_channel_get);
>  
>