[-next] gpiolib: acpi: Use LIST_HEAD() to initialize the list_head

Use LIST_HEAD() to initialize the list_head instead of open-coding it.

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
---
 drivers/gpio/gpiolib-acpi.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

On Sat, Aug 12, 2023 at 9:14 AM Ruan Jinjie <ruanjinjie@huawei.com> wrote:
>
> Use LIST_HEAD() to initialize the list_head instead of open-coding it.
>
> Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
> ---
>  drivers/gpio/gpiolib-acpi.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
> index fbda452fb4d6..db8e8e967bda 100644
> --- a/drivers/gpio/gpiolib-acpi.c
> +++ b/drivers/gpio/gpiolib-acpi.c
> @@ -809,11 +809,9 @@ static int acpi_gpio_resource_lookup(struct acpi_gpio_lookup *lookup,
>                                      struct acpi_gpio_info *info)
>  {
>         struct acpi_device *adev = lookup->info.adev;
> -       struct list_head res_list;
> +       LIST_HEAD(res_list);
>         int ret;
>
> -       INIT_LIST_HEAD(&res_list);
> -
>         ret = acpi_dev_get_resources(adev, &res_list,
>                                      acpi_populate_gpio_lookup,
>                                      lookup);
> @@ -1472,13 +1470,12 @@ int acpi_gpio_count(struct device *dev, const char *con_id)
>
>         /* Then from plain _CRS GPIOs */
>         if (count < 0) {
> -               struct list_head resource_list;
> +               LIST_HEAD(resource_list);
>                 unsigned int crs_count = 0;
>
>                 if (!acpi_can_fallback_to_crs(adev, con_id))
>                         return count;
>
> -               INIT_LIST_HEAD(&resource_list);
>                 acpi_dev_get_resources(adev, &resource_list,
>                                        acpi_find_gpio_count, &crs_count);
>                 acpi_dev_free_resource_list(&resource_list);
> --
> 2.34.1
>

My opinion: this is actually less readable than what is there now and
I doubt the compiler would generate less code. With this change I now
need to check what LIST_HEAD() actually does, while defining a temp
variable of a clear type and then using a macro to initialize it is
much more obvious.

I'll let Andy decide as ACPI is his domain but for me it's a NAK.

Bart

On Sun, Aug 13, 2023 at 08:49:28PM +0200, Bartosz Golaszewski wrote:
> On Sat, Aug 12, 2023 at 9:14 AM Ruan Jinjie <ruanjinjie@huawei.com> wrote:
> >
> > Use LIST_HEAD() to initialize the list_head instead of open-coding it.

...

> My opinion: this is actually less readable than what is there now and
> I doubt the compiler would generate less code. With this change I now
> need to check what LIST_HEAD() actually does, while defining a temp
> variable of a clear type and then using a macro to initialize it is
> much more obvious.
> 
> I'll let Andy decide as ACPI is his domain but for me it's a NAK.

The code is identical, I have no strong opinion (I'm fine with the either),
since you already have an opinion, let it be NAK then.