Re: [PATCH 2/2] iio: inkern: clean up error return code

From: Jonathan Cameron
Date: Sat Sep 22 2012 - 05:14:26 EST


On 09/18/2012 05:56 AM, Kim, Milo wrote:
> When the IIO consumer tries to get specific IIO channel,
> few error cases can be happened.
> (a) Memory allocation failure
> (b) No matched ADC channel error
> (c) Invalid input arguments
> This patch enables cleaning up error handling in case of (a) and (b).
>
> In error handling code,
> (a): the reference count of the IIO device should be decreased.
> (b): the allocated memory should be freed with restoring the reference count.
> Therefore iio_deivce_put() is called in both cases.
> This can be handled in the last error statement.
>
> Additionally, integer variable is used for stating each error case explicitly.
> Then, the error returns as ERR_PTR() with this value.
>
> Signed-off-by: Milo(Woogyom) Kim <milo.kim@xxxxxx>
Thanks,
added to togreg branch of iio.git
> ---
> drivers/iio/inkern.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
> index aff034b..656d4d4 100644
> --- a/drivers/iio/inkern.c
> +++ b/drivers/iio/inkern.c
> @@ -111,6 +111,7 @@ struct iio_channel *iio_channel_get(const char *name, const char *channel_name)
> {
> struct iio_map_internal *c_i = NULL, *c = NULL;
> struct iio_channel *channel;
> + int err;
>
> if (name == NULL && channel_name == NULL)
> return ERR_PTR(-ENODEV);
> @@ -131,8 +132,10 @@ struct iio_channel *iio_channel_get(const char *name, const char *channel_name)
> return ERR_PTR(-ENODEV);
>
> channel = kzalloc(sizeof(*channel), GFP_KERNEL);
> - if (channel == NULL)
> + if (channel == NULL) {
> + err = -ENOMEM;
> goto error_no_mem;
> + }
>
> channel->indio_dev = c->indio_dev;
>
> @@ -141,19 +144,19 @@ struct iio_channel *iio_channel_get(const char *name, const char *channel_name)
> iio_chan_spec_from_name(channel->indio_dev,
> c->map->adc_channel_label);
>
> - if (channel->channel == NULL)
> + if (channel->channel == NULL) {
> + err = -EINVAL;
> goto error_no_chan;
> + }
> }
>
> return channel;
>
> error_no_chan:
> - iio_device_put(c->indio_dev);
> kfree(channel);
> - return ERR_PTR(-EINVAL);
> error_no_mem:
> iio_device_put(c->indio_dev);
> - return ERR_PTR(-ENOMEM);
> + return ERR_PTR(err);
> }
> EXPORT_SYMBOL_GPL(iio_channel_get);
>
>
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