linux-kernel - Re: [PATCH v2] ACPI: platform_profile: Improve platform_profile

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Message-Id: <bc0a60ef-bdf7-4f48-8215-891cb1efbdf5@app.fastmail.com>
Date: Wed, 12 Feb 2025 15:41:44 -0500
From: "Mark Pearson" <mpearson-lenovo@...ebb.ca>
To: "Kurt Borja" <kuurtb@...il.com>, "Rafael J. Wysocki" <rafael@...nel.org>
Cc: "Len Brown" <lenb@...nel.org>,
 "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
 linux-kernel@...r.kernel.org,
 Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
 "Limonciello, Mario" <mario.limonciello@....com>,
 "platform-driver-x86@...r.kernel.org" <platform-driver-x86@...r.kernel.org>
Subject: Re: [PATCH v2] ACPI: platform_profile: Improve platform_profile_unregister

Hi Kurt

On Wed, Feb 12, 2025, at 2:03 PM, Kurt Borja wrote:
> Drivers usually call this method on error/exit paths and do not check
> for it's return value, which is always 0 anyway, so make it void. This
> is safe to do as currently all drivers use
> devm_platform_profile_register().
>
I was worried I had mucked that up with the revert done in thinkpad_acpi? But it's not checking the return there so I think it's fine

> While at it improve the style and make the function safer by checking
> for IS_ERR_OR_NULL before dereferencing the device pointer.
>
> Signed-off-by: Kurt Borja <kuurtb@...il.com>
> ---
> Hi all,
>
> I made a little modification that I forgot in the last version.
>
> Rafael, please tell me if you prefer different commits for this. Also
> should we WARN_ON(IS_ERR_OR_NULL)?
>
> Based on the acpi branch of the linux-pm tree.
>
> ~ Kurt
>
> Changes in v2:
>   - Get reference to pprof after checking for IS_ERR_OR_NULL(dev)
>   - CC Mark Pearson (sorry!)
>
>  drivers/acpi/platform_profile.c  | 19 +++++++++----------
>  include/linux/platform_profile.h |  2 +-
>  2 files changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
> index fc92e43d0fe9..ed9c0cc9ea9c 100644
> --- a/drivers/acpi/platform_profile.c
> +++ b/drivers/acpi/platform_profile.c
> @@ -569,24 +569,23 @@ EXPORT_SYMBOL_GPL(platform_profile_register);
>  /**
>   * platform_profile_remove - Unregisters a platform profile class device
>   * @dev: Class device
> - *
> - * Return: 0
>   */
> -int platform_profile_remove(struct device *dev)
> +void platform_profile_remove(struct device *dev)
>  {
> -	struct platform_profile_handler *pprof = to_pprof_handler(dev);
> -	int id;
> +	struct platform_profile_handler *pprof;
> +
> +	if (IS_ERR_OR_NULL(dev))
> +		return;
> +
> +	pprof = to_pprof_handler(dev);
> +
>  	guard(mutex)(&profile_lock);
> 
> -	id = pprof->minor;
> +	ida_free(&platform_profile_ida, pprof->minor);
>  	device_unregister(&pprof->dev);
> -	ida_free(&platform_profile_ida, id);
> 
>  	sysfs_notify(acpi_kobj, NULL, "platform_profile");
> -
>  	sysfs_update_group(acpi_kobj, &platform_profile_group);
> -
> -	return 0;
>  }
>  EXPORT_SYMBOL_GPL(platform_profile_remove);
> 
> diff --git a/include/linux/platform_profile.h 
> b/include/linux/platform_profile.h
> index 8ab5b0e8eb2c..d5499eca9e1d 100644
> --- a/include/linux/platform_profile.h
> +++ b/include/linux/platform_profile.h
> @@ -47,7 +47,7 @@ struct platform_profile_ops {
>  struct device *platform_profile_register(struct device *dev, const 
> char *name,
>  					 void *drvdata,
>  					 const struct platform_profile_ops *ops);
> -int platform_profile_remove(struct device *dev);
> +void platform_profile_remove(struct device *dev);
>  struct device *devm_platform_profile_register(struct device *dev, 
> const char *name,
>  					      void *drvdata,
>  					      const struct platform_profile_ops *ops);
>
> base-commit: 3e3e377dd1f300bbdd230533686ce9c9f4f8a90d
> -- 
> 2.48.1
Looks good to me
Reviewed-by: Mark Pearson <mpearson-lenovo@...ebb.ca>

Mark