linux-kernel - Re: [PATCH v5 10/20] ACPI: platform_profile: Add name attribute to class interface

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Message-ID: <d4281684-9055-4106-b357-79a0f415e129@gmx.de>
Date: Thu, 7 Nov 2024 09:23:08 +0100
From: Armin Wolf <W_Armin@....de>
To: Mario Limonciello <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>,
 "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 v5 10/20] ACPI: platform_profile: Add name attribute to
 class interface

Am 07.11.24 um 07:02 schrieb Mario Limonciello:

> The name attribute shows the name of the associated platform profile
> handler.
>
> Tested-by: Mark Pearson <mpearson-lenovo@...ebb.ca>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
> v5:
>   * Drop newline
>   * Add mutex for sysfs access
> ---
>   drivers/acpi/platform_profile.c | 27 +++++++++++++++++++++++++++
>   1 file changed, 27 insertions(+)
>
> diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
> index 9caf070f77f6a..f605c2bd35c68 100644
> --- a/drivers/acpi/platform_profile.c
> +++ b/drivers/acpi/platform_profile.c
> @@ -25,8 +25,35 @@ static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST);
>
>   static DEFINE_IDA(platform_profile_ida);
>
> +/**
> + * name_show - Show the name of the profile handler
> + * @dev: The device
> + * @attr: The attribute
> + * @buf: The buffer to write to
> + * Return: The number of bytes written
> + */
> +static ssize_t name_show(struct device *dev,
> +			 struct device_attribute *attr,
> +			 char *buf)
> +{
> +	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
> +		struct platform_profile_handler *handler = dev_get_drvdata(dev);
> +
> +		return sysfs_emit(buf, "%s\n", handler->name);
> +	}
> +	return -ERESTARTSYS;

Is the mutex really necessary here? The name remains static across the lifetime of the platform profile.

Thanks,
Armin Wolf

> +}
> +
> +static DEVICE_ATTR_RO(name);
> +static struct attribute *profile_attrs[] = {
> +	&dev_attr_name.attr,
> +	NULL
> +};
> +ATTRIBUTE_GROUPS(profile);
> +
>   static const struct class platform_profile_class = {
>   	.name = "platform-profile",
> +	.dev_groups = profile_groups,
>   };
>
>   static ssize_t platform_profile_choices_show(struct device *dev,