Re: [PATCH] iio: core: return -EINVAL when no ioctl handler has been run

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 17 Nov 2020 11:51:54 +0200
Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:

> It seems that when this was tested the happy case was more tested. A few of
> the userspace apps rely on this returning negative error codes in case an
> ioctl() is not available.
> 
> When running multiple ioctl() handlers or when calling an ioctl() that
> doesn't exist, IIO_IOCTL_UNHANDLED is returned. In that case -EINVAL should
> be returned.
> 
> Fixes: 8dedcc3eee3a ("iio: core: centralize ioctl() calls to the main chardev")
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Applied.

Thanks,

Jonathan

> ---
> 
> Apologies for not noticing this earlier.
> This came up when trying to write more IIO buffer code.
> 
> From my side either is fine: whether it be applied as a fix or whether
> it's squashed into the original patch.
> 
>  drivers/iio/industrialio-core.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index e53c771d66eb..419d6f8acc13 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -1743,6 +1743,9 @@ static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  			break;
>  	}
>  
> +	if (ret == IIO_IOCTL_UNHANDLED)
> +		ret = -EINVAL;
> +
>  out_unlock:
>  	mutex_unlock(&indio_dev->info_exist_lock);
>