Re: [PATCH] iio: humidity: ens210: remove compiler warning workaround

[Maxwell Doose]

Hi David,

On Thu, May 21, 2026 at 8:26 PM David Lechner <dlechner@xxxxxxxxxxxx> wrote:
>
> Rewrite IIO_CHAN_INFO_RAW case to avoid needing to add unreachable code
> to work around a compiler warning.
>
> When scoped_guard() was first introduced, compilers could not see when
> it returned unconditionally from inside the hidden for loop. This has
> since been fixed in the macro definition. So removing the `return
> -EINVAL` should be enough. Still, we can improve readability, decrease
> indentation and avoid the hidden for loop by rewriting the case without
> scoped_guard().
>
> Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx>
> ---
>  drivers/iio/humidity/ens210.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/iio/humidity/ens210.c b/drivers/iio/humidity/ens210.c
> index 22ad208e6aa6..49543fc389bf 100644
> --- a/drivers/iio/humidity/ens210.c
> +++ b/drivers/iio/humidity/ens210.c
> @@ -149,15 +149,16 @@ static int ens210_read_raw(struct iio_dev *indio_dev,
>         int ret;
>
>         switch (mask) {
> -       case IIO_CHAN_INFO_RAW:
> -               scoped_guard(mutex, &data->lock) {
> -                       ret = ens210_get_measurement(
> -                               indio_dev, channel->type == IIO_TEMP, val);
> -                       if (ret)
> -                               return ret;
> -                       return IIO_VAL_INT;
> -               }
> -               return -EINVAL; /* compiler warning workaround */
> +       case IIO_CHAN_INFO_RAW: {
> +               guard(mutex)(&data->lock);
> +
> +               ret = ens210_get_measurement(indio_dev, channel->type == IIO_TEMP,
> +                                            val);
> +               if (ret)
> +                       return ret;
> +
> +               return IIO_VAL_INT;
> +       }
>         case IIO_CHAN_INFO_SCALE:
>                 if (channel->type == IIO_TEMP) {
>                         *val = 15;
>

I'm questioning how that initial commit got merged at all, they
could've just used guard()() with {} (the kind of thing to make me
want to take a look at this file even further!). Visually looks good
to me but will follow-up later with rb if it all checks out.

best regards,
max


> ---
> base-commit: e1a29334a9c043defe7a9363fa76d399d3fdfbec
> change-id: 20260521-iio-humidity-ens210-remove-hack-7c5a6496547c
>
> Best regards,
> --
> David Lechner <dlechner@xxxxxxxxxxxx>
>
>