On Mon, Feb 3, 2025 at 8:47 PM Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>
> While analysing code for software and OF node for the corner case when
> caller asks to read zero items in the supposed to be an array of values
> I found that ACPI behaves differently to what OF does, i.e.
>
> 1. It returns -EINVAL when caller asks to read zero items from integer
> array, while OF returns 0, if no other errors happened.
>
> 2. It returns -EINVAL when caller asks to read zero items from string
> array, while OF returns -ENODATA, if no other errors happened.
>
> Amend ACPI implementation to follow what OF does.
>
> Fixes: b31384fa5de3 ("Driver core: Unified device properties interface for platform firmware")
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
> drivers/acpi/property.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> index 1144c2368d89..7d7f4974c5b1 100644
> --- a/drivers/acpi/property.c
> +++ b/drivers/acpi/property.c
> @@ -1189,8 +1189,6 @@ static int acpi_data_prop_read(const struct acpi_device_data *data,
> return -EOVERFLOW;
> break;
> }
> - if (nval == 0)
> - return -EINVAL;
>
> if (obj->type == ACPI_TYPE_BUFFER) {
> if (proptype != DEV_PROP_U8)
> @@ -1214,9 +1212,10 @@ static int acpi_data_prop_read(const struct acpi_device_data *data,
> ret = acpi_copy_property_array_uint(items, (u64 *)val, nval);
> break;
> case DEV_PROP_STRING:
> - ret = acpi_copy_property_array_string(
> - items, (char **)val,
> - min_t(u32, nval, obj->package.count));
> + nval = min_t(u32, nval, obj->package.count);
> + if (nval == 0)
> + return -ENODATA;
> + ret = acpi_copy_property_array_string(items, (char **)val, nval);
> break;
> default:
> ret = -EINVAL;
> --
Applied as 6.14-rc material, thanks!
