linux-kernel - Re: [PATCH v3 19/22] ACPI: platform_profile: Check all profile handler to calculate next

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Message-ID: <86d94339-3651-c4ea-306c-05589bee0040@linux.intel.com>
Date: Thu, 31 Oct 2024 12:40:26 +0200 (EET)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Mario Limonciello <mario.limonciello@....com>
cc: Hans de Goede <hdegoede@...hat.com>, 
    "Rafael J . Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>, 
    Maximilian Luz <luzmaximilian@...il.com>, Lee Chun-Yi <jlee@...e.com>, 
    Shyam Sundar S K <Shyam-sundar.S-k@....com>, 
    Corentin Chary <corentin.chary@...il.com>, 
    "Luke D . Jones" <luke@...nes.dev>, Ike Panhc <ike.pan@...onical.com>, 
    Henrique de Moraes Holschuh <hmh@....eng.br>, 
    Alexis Belmonte <alexbelm48@...il.com>, 
    Uwe Kleine-König <u.kleine-koenig@...gutronix.de>, 
    Ai Chao <aichao@...inos.cn>, Gergo Koteles <soyer@....hu>, 
    open list <linux-kernel@...r.kernel.org>, 
    "open list:ACPI" <linux-acpi@...r.kernel.org>, 
    "open list:MICROSOFT SURFACE PLATFORM PROFILE DRIVER" <platform-driver-x86@...r.kernel.org>, 
    "open list:THINKPAD ACPI EXTRAS DRIVER" <ibm-acpi-devel@...ts.sourceforge.net>, 
    Mark Pearson <mpearson-lenovo@...ebb.ca>, 
    Matthew Schwartz <matthew.schwartz@...ux.dev>
Subject: Re: [PATCH v3 19/22] ACPI: platform_profile: Check all profile
 handler to calculate next

On Wed, 30 Oct 2024, Mario Limonciello wrote:

> As multiple platform profile handlers might not all support the same
> profile, cycling to the next profile could have a different result
> depending on what handler are registered.
> 
> Check what is active and supported by all handlers to decide what
> to do.
> 
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
>  drivers/acpi/platform_profile.c | 35 ++++++++++++++++++++++-----------
>  1 file changed, 23 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
> index 5baac1f9a9c0e..9b681884ae324 100644
> --- a/drivers/acpi/platform_profile.c
> +++ b/drivers/acpi/platform_profile.c
> @@ -187,30 +187,41 @@ EXPORT_SYMBOL_GPL(platform_profile_notify);
>  
>  int platform_profile_cycle(void)
>  {
> +	enum platform_profile_option next = PLATFORM_PROFILE_LAST;
> +	struct platform_profile_handler *handler;
>  	enum platform_profile_option profile;
> -	enum platform_profile_option next;
> +	unsigned long choices;
>  	int err;
>  
>  	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
> -		if (!cur_profile)
> -			return -ENODEV;
> -
> -		err = cur_profile->profile_get(cur_profile, &profile);
> +		err = platform_profile_get_active(&profile);

If platform_profile_cycle() is called without any profiles registered, 
platform_profile_get_active() will return success.

I suppose you'd want check first that there is one registered and return 
-EINVAL if none are, especially since this is an exported function.

>  		if (err)
>  			return err;
>  
> -		next = find_next_bit_wrap(cur_profile->choices, PLATFORM_PROFILE_LAST,
> -					  profile + 1);
> +		choices = platform_profile_get_choices();
>  
> -		if (WARN_ON(next == PLATFORM_PROFILE_LAST))
> -			return -EINVAL;
> +		next = find_next_bit_wrap(&choices,
> +					  PLATFORM_PROFILE_LAST,
> +					  profile + 1);
>  
> -		err = cur_profile->profile_set(cur_profile, next);
> -		if (err)
> -			return err;
> +		list_for_each_entry(handler, &platform_profile_handler_list, list) {
> +			err = handler->profile_set(handler, next);
> +			if (err) {
> +				pr_err("Failed to set profile for handler %s\n", handler->name);
> +				break;
> +			}
> +		}
> +		if (err) {

Same here, instead of break you could goto to a rollback label to 
deindent the rollback loop a lot and make the code flow more obvious too.

> +			list_for_each_entry_continue_reverse(handler, &platform_profile_handler_list, list) {
> +				err = handler->profile_set(handler, PLATFORM_PROFILE_BALANCED);
> +				if (err)
> +					pr_err("Failed to revert profile for handler %s\n", handler->name);
> +			}
> +		}
>  	}
>  
>  	sysfs_notify(acpi_kobj, NULL, "platform_profile");
> +
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(platform_profile_cycle);
> 

-- 
 i.