Re: [PATCH v5 16/20] ACPI: platform_profile: Make sure all profile handlers agree on profile

[Armin Wolf <W_Armin@gmx.de>]

Am 07.11.24 um 07:02 schrieb Mario Limonciello:

> If for any reason multiple profile handlers don't agree on the profile
> return the custom profile.
>
> Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
> Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
> v5:
>   * Notify class profile of change to legacy interface
>   * Don't show warning when writing custom string, document in last patch
>     instead.
>   * Adjust mutex use
> ---
>   drivers/acpi/platform_profile.c | 101 ++++++++++++++++++++++++--------
>   1 file changed, 76 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
> index b6f3388b4eef9..7f302ac4d3779 100644
> --- a/drivers/acpi/platform_profile.c
> +++ b/drivers/acpi/platform_profile.c
> @@ -94,6 +94,22 @@ static int _store_class_profile(struct device *dev, void *data)
>   	return err ? err : 0;
>   }
>
> +/**
> + * _notify_class_profile - Notify the class device of a profile change
> + * @dev: The class device
> + * @data: Unused
> + */
> +static int _notify_class_profile(struct device *dev, void *data)
> +{
> +	struct platform_profile_handler *handler = dev_get_drvdata(dev);
> +
> +	lockdep_assert_held(&profile_lock);
> +	sysfs_notify(&handler->class_dev->kobj, NULL, "platform_profile");
> +	kobject_uevent(&handler->class_dev->kobj, KOBJ_CHANGE);
> +
> +	return 0;
> +}
> +
>   /**
>    * get_class_profile - Show the current profile for a class device
>    * @dev: The class device
> @@ -284,54 +300,89 @@ static ssize_t platform_profile_choices_show(struct device *dev,
>   	return _commmon_choices_show(aggregate, buf);
>   }
>
> +/**
> + * _aggregate_profiles - Aggregate the profiles for legacy sysfs interface
> + * @dev: The device
> + * @data: The profile to return
> + * Return: 0 on success, -errno on failure
> + */
> +static int _aggregate_profiles(struct device *dev, void *data)
> +{
> +	enum platform_profile_option *profile = data;
> +	enum platform_profile_option val;
> +	int err;
> +
> +	err = get_class_profile(dev, &val);
> +	if (err)
> +		return err;
> +
> +	if (*profile != PLATFORM_PROFILE_LAST && *profile != val)
> +		*profile = PLATFORM_PROFILE_CUSTOM;
> +	else
> +		*profile = val;
> +
> +	return 0;
> +}
> +
> +/**
> + * platform_profile_show - Show the current profile for legacy sysfs interface
> + * @dev: The device
> + * @attr: The attribute
> + * @buf: The buffer to write to
> + * Return: The number of bytes written
> + */
>   static ssize_t platform_profile_show(struct device *dev,
> -					struct device_attribute *attr,
> -					char *buf)
> +				     struct device_attribute *attr,
> +				     char *buf)
>   {
> -	enum platform_profile_option profile = PLATFORM_PROFILE_BALANCED;
> +	enum platform_profile_option profile = PLATFORM_PROFILE_LAST;
>   	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 = class_for_each_device(&platform_profile_class, NULL,
> +					    &profile, _aggregate_profiles);
>   		if (err)
>   			return err;
>   	}
>
> -	/* Check that profile is valid index */
> -	if (WARN_ON((profile < 0) || (profile >= ARRAY_SIZE(profile_names))))
> -		return -EIO;
> +	/* no profile handler registered any more */
> +	if (profile == PLATFORM_PROFILE_LAST)
> +		return -EINVAL;
>
>   	return sysfs_emit(buf, "%s\n", profile_names[profile]);
>   }
>
> +/**
> + * platform_profile_store - Set the profile for legacy sysfs interface
> + * @dev: The device
> + * @attr: The attribute
> + * @buf: The buffer to read from
> + * @count: The number of bytes to read
> + * Return: The number of bytes read
> + */
>   static ssize_t platform_profile_store(struct device *dev,
> -			    struct device_attribute *attr,
> -			    const char *buf, size_t count)
> +				      struct device_attribute *attr,
> +				      const char *buf, size_t count)
>   {
> -	int err, i;
> +	int ret;
> +	int i;
>
>   	/* Scan for a matching profile */
>   	i = sysfs_match_string(profile_names, buf);
> -	if (i < 0)
> +	if (i < 0 || PLATFORM_PROFILE_CUSTOM)

This condition looks a bit weird.

>   		return -EINVAL;
>
>   	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
> -		if (!cur_profile)
> -			return -ENODEV;
> -
> -		/* Check that platform supports this profile choice */
> -		if (!test_bit(i, cur_profile->choices))
> -			return -EOPNOTSUPP;
> -
> -		err = cur_profile->profile_set(cur_profile, i);
> -		if (err)
> -			return err;
> +		ret = class_for_each_device(&platform_profile_class, NULL, &i,
> +					    _store_class_profile);
> +		if (ret)
> +			return ret;
> +		ret = class_for_each_device(&platform_profile_class, NULL, NULL,
> +					    _notify_class_profile);

Please rework _store_class_profile()  and _notify_class_profile() into:

- platform_profile_store(struct platform_profile_handler,enumplatform_profile_option option),
   which is called by profile_store() while holding profile_lock.

- platform_profile_class_store(struct device *dev, void *data), which is used with class_for_each_device()
   and internally calls platform_profile_store() and issues an notification on the "profile" (not "platform_profile"!)
   class attribute and an uevent.

This allows you to avoid having to iterate through all platform profile handlers twice.

Thanks,
Armin Wolf

> +		if (ret)
> +			return ret;
>   	}
>
> -	sysfs_notify(acpi_kobj, NULL, "platform_profile");
>   	return count;
>   }
>