On Fri, 15 Apr 2022 09:20:37 +0800
Haowen Bai <baihaowen@xxxxxxxxx> wrote:
> function gp2ap020a00f_get_thresh_reg() is unsigned but returning -EINVAL
> errcode, and thresh_reg_l is unsigned but receiving -EINVAL errcode. so
> we have to change u8 -> int.
>
> Signed-off-by: Haowen Bai <baihaowen@xxxxxxxxx>
Hi,
The return value is not checked in *read_event_val(), so if we actually got
-EINVAL (in reality we can't because the switch in *_get_thresh_reg*) always
matches) then we'd use it to index an array (after performing some maths on
the value). So please also add a check that the return value is not
negative in read_event_val()
Same is true or write_event_val.
Note that the bug here is probably the fact we return -EINVAL in the
first place. We could just stop doing that but it would be non obvious
when looking at the code that we couldn't get a failure to match in
the switch statement - so fixing as you have done (plus the extra
check I'm requesting) is probably the neatest solution.
Thanks,
Jonathan
> ---
> V1->V2: s8 is not enough to hold an (arbitrary) error code. To be on the safe
> side we need to use int
>
> drivers/iio/light/gp2ap020a00f.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/light/gp2ap020a00f.c b/drivers/iio/light/gp2ap020a00f.c
> index b820041159f7..b0e62d3c6fa0 100644
> --- a/drivers/iio/light/gp2ap020a00f.c
> +++ b/drivers/iio/light/gp2ap020a00f.c
> @@ -994,7 +994,7 @@ static irqreturn_t gp2ap020a00f_trigger_handler(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> -static u8 gp2ap020a00f_get_thresh_reg(const struct iio_chan_spec *chan,
> +static int gp2ap020a00f_get_thresh_reg(const struct iio_chan_spec *chan,
> enum iio_event_direction event_dir)
> {
> switch (chan->type) {
> @@ -1025,7 +1025,7 @@ static int gp2ap020a00f_write_event_val(struct iio_dev *indio_dev,
> struct gp2ap020a00f_data *data = iio_priv(indio_dev);
> bool event_en = false;
> u8 thresh_val_id;
> - u8 thresh_reg_l;
> + int thresh_reg_l;
> int err = 0;
>
> mutex_lock(&data->lock);
> @@ -1082,7 +1082,7 @@ static int gp2ap020a00f_read_event_val(struct iio_dev *indio_dev,
> int *val, int *val2)
> {
> struct gp2ap020a00f_data *data = iio_priv(indio_dev);
> - u8 thresh_reg_l;
> + int thresh_reg_l;
> int err = IIO_VAL_INT;
>
> mutex_lock(&data->lock);
