linux-kernel - Re: [PATCH v3 1/6] ACPI: AC: Remove unnecessary checks

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Message-ID: <CAJZ5v0gGi5joPQ2dCUs_oPZgPqT_=Y-z7epXE2mfYdmp7DOwQQ@mail.gmail.com>
Date:   Fri, 13 Oct 2023 19:33:08 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Michal Wilczynski <michal.wilczynski@...el.com>
Cc:     linux-acpi@...r.kernel.org, rafael@...nel.org,
        dan.j.williams@...el.com, vishal.l.verma@...el.com,
        lenb@...nel.org, dave.jiang@...el.com, ira.weiny@...el.com,
        rui.zhang@...el.com, linux-kernel@...r.kernel.org,
        nvdimm@...ts.linux.dev
Subject: Re: [PATCH v3 1/6] ACPI: AC: Remove unnecessary checks

On Wed, Oct 11, 2023 at 10:34 AM Michal Wilczynski
<michal.wilczynski@...el.com> wrote:
>
> Remove unnecessary checks for NULL for variables that can't be NULL at
> the point they're checked for it. Defensive programming is discouraged
> in the kernel.
>
> Signed-off-by: Michal Wilczynski <michal.wilczynski@...el.com>
> ---
>  drivers/acpi/ac.c | 27 ++++-----------------------
>  1 file changed, 4 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/acpi/ac.c b/drivers/acpi/ac.c
> index aac3e561790c..83d45c681121 100644
> --- a/drivers/acpi/ac.c
> +++ b/drivers/acpi/ac.c
> @@ -131,9 +131,6 @@ static void acpi_ac_notify(acpi_handle handle, u32 event, void *data)
>         struct acpi_device *device = data;
>         struct acpi_ac *ac = acpi_driver_data(device);
>
> -       if (!ac)
> -               return;
> -
>         switch (event) {
>         default:
>                 acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
> @@ -216,12 +213,8 @@ static const struct dmi_system_id ac_dmi_table[]  __initconst = {
>  static int acpi_ac_add(struct acpi_device *device)
>  {
>         struct power_supply_config psy_cfg = {};
> -       int result = 0;
> -       struct acpi_ac *ac = NULL;
> -
> -
> -       if (!device)
> -               return -EINVAL;
> +       struct acpi_ac *ac;
> +       int result;
>
>         ac = kzalloc(sizeof(struct acpi_ac), GFP_KERNEL);
>         if (!ac)
> @@ -275,16 +268,9 @@ static int acpi_ac_add(struct acpi_device *device)
>  #ifdef CONFIG_PM_SLEEP
>  static int acpi_ac_resume(struct device *dev)
>  {
> -       struct acpi_ac *ac;
> +       struct acpi_ac *ac = acpi_driver_data(to_acpi_device(dev));
>         unsigned int old_state;
>
> -       if (!dev)
> -               return -EINVAL;
> -
> -       ac = acpi_driver_data(to_acpi_device(dev));
> -       if (!ac)
> -               return -EINVAL;
> -
>         old_state = ac->state;
>         if (acpi_ac_get_state(ac))
>                 return 0;
> @@ -299,12 +285,7 @@ static int acpi_ac_resume(struct device *dev)
>
>  static void acpi_ac_remove(struct acpi_device *device)
>  {
> -       struct acpi_ac *ac = NULL;
> -
> -       if (!device || !acpi_driver_data(device))
> -               return;
> -
> -       ac = acpi_driver_data(device);
> +       struct acpi_ac *ac = acpi_driver_data(device);
>
>         acpi_dev_remove_notify_handler(device, ACPI_ALL_NOTIFY,
>                                        acpi_ac_notify);
> --

Applied as 6.7 material with edits in the subject and changelog, thanks!