linux-kernel - Re: [PATCH 5/8] ACPI: platform_profile: Use guard(mutex) for register/unregister

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Message-Id: <bac1b29b-91db-409a-b07a-55a183b6d686@app.fastmail.com>
Date: Mon, 28 Oct 2024 06:10:29 -0400
From: "Mark Pearson" <mpearson-lenovo@...ebb.ca>
To: "Limonciello, Mario" <mario.limonciello@....com>,
 "Hans de Goede" <hdegoede@...hat.com>,
 Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: "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>,
 "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
 "platform-driver-x86@...r.kernel.org" <platform-driver-x86@...r.kernel.org>,
 "open list:THINKPAD ACPI EXTRAS DRIVER" <ibm-acpi-devel@...ts.sourceforge.net>,
 "Matthew Schwartz" <matthew.schwartz@...ux.dev>
Subject: Re: [PATCH 5/8] ACPI: platform_profile: Use guard(mutex) for
 register/unregister

On Fri, Oct 25, 2024, at 3:30 PM, Mario Limonciello wrote:
> guard(mutex) can be used to automatically release mutexes when going
> out of scope.
>
> Tested-by: Matthew Schwartz <matthew.schwartz@...ux.dev>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
>  drivers/acpi/platform_profile.c | 19 ++++++-------------
>  1 file changed, 6 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/acpi/platform_profile.c 
> b/drivers/acpi/platform_profile.c
> index 0c60fc970b6e8..81928adccfade 100644
> --- a/drivers/acpi/platform_profile.c
> +++ b/drivers/acpi/platform_profile.c
> @@ -180,41 +180,34 @@ int platform_profile_register(struct 
> platform_profile_handler *pprof)
>  {
>  	int err;
> 
> -	mutex_lock(&profile_lock);
> +	guard(mutex)(&profile_lock);
>  	/* We can only have one active profile */
> -	if (cur_profile) {
> -		mutex_unlock(&profile_lock);
> +	if (cur_profile)
>  		return -EEXIST;
> -	}
> 
>  	/* Sanity check the profile handler field are set */
>  	if (!pprof || bitmap_empty(pprof->choices, PLATFORM_PROFILE_LAST) ||
> -		!pprof->profile_set || !pprof->profile_get) {
> -		mutex_unlock(&profile_lock);
> +		!pprof->profile_set || !pprof->profile_get)
>  		return -EINVAL;
> -	}
> 
>  	err = sysfs_create_group(acpi_kobj, &platform_profile_group);
> -	if (err) {
> -		mutex_unlock(&profile_lock);
> +	if (err)
>  		return err;
> -	}
>  	list_add_tail(&pprof->list, &platform_profile_handler_list);
> 
>  	cur_profile = pprof;
> -	mutex_unlock(&profile_lock);
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(platform_profile_register);
> 
>  int platform_profile_remove(struct platform_profile_handler *pprof)
>  {
> +	guard(mutex)(&profile_lock);
> +
>  	list_del(&pprof->list);
> 
>  	sysfs_remove_group(acpi_kobj, &platform_profile_group);
> -	mutex_lock(&profile_lock);
>  	cur_profile = NULL;
> -	mutex_unlock(&profile_lock);
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(platform_profile_remove);
> -- 
> 2.43.0

Looks good to me.
Reviewed-by: Mark Pearson <mpearson-lenovo@...ebb.ca>

Mark