linux-kernel - Re: [PATCH v2 10/15] ACPI: platform_profile: Only show profiles common for all handlers

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Message-ID: <031cacd1-02a5-b411-7ecf-287d45883192@linux.intel.com>
Date: Tue, 29 Oct 2024 12:19:13 +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 v2 10/15] ACPI: platform_profile: Only show profiles
 common for all handlers

On Sun, 27 Oct 2024, Mario Limonciello wrote:

> If multiple platform profile handlers have been registered, don't allow
> switching to profiles unique to only one handler.
> 
> Tested-by: Matthew Schwartz <matthew.schwartz@...ux.dev>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
>  drivers/acpi/platform_profile.c | 35 ++++++++++++++++++++++-----------
>  1 file changed, 24 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
> index 5fee467614eac..a83842f05022b 100644
> --- a/drivers/acpi/platform_profile.c
> +++ b/drivers/acpi/platform_profile.c
> @@ -33,30 +33,43 @@ static bool platform_profile_is_registered(void)
>  	return count > 0;
>  }
>  
> +/* expected to be called under mutex */
> +static unsigned long platform_profile_get_choices(void)
> +{
> +	struct platform_profile_handler *handler;
> +	unsigned long seen = 0;
> +	int i;
> +
> +	list_for_each_entry(handler, &platform_profile_handler_list, list) {
> +		for_each_set_bit(i, handler->choices, PLATFORM_PROFILE_LAST) {
> +			if (seen & BIT(i))
> +				continue;
> +			seen |= BIT(i);

The condition+continue part seems unnecessary if all this function does is 
accumulate bits into seen.

-- 
 i.

> +		}
> +	}
> +
> +	return seen;
> +}
> +
>  static ssize_t platform_profile_choices_show(struct device *dev,
>  					struct device_attribute *attr,
>  					char *buf)
>  {
> +	unsigned long choices;
>  	int len = 0;
> -	int err, i;
> -
> -	err = mutex_lock_interruptible(&profile_lock);
> -	if (err)
> -		return err;
> +	int i;
>  
> -	if (!cur_profile) {
> -		mutex_unlock(&profile_lock);
> -		return -ENODEV;
> -	}
> +	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock)
> +		choices = platform_profile_get_choices();
> -	for_each_set_bit(i, cur_profile->choices, PLATFORM_PROFILE_LAST) {
> +	for_each_set_bit(i, &choices, PLATFORM_PROFILE_LAST) {
>  		if (len == 0)
>  			len += sysfs_emit_at(buf, len, "%s", profile_names[i]);
>  		else
>  			len += sysfs_emit_at(buf, len, " %s", profile_names[i]);
>  	}
> +
>  	len += sysfs_emit_at(buf, len, "\n");
> -	mutex_unlock(&profile_lock);
>  	return len;
>  }
>  
>