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Message-ID: <b5b942fd-9c64-48a0-9c3d-64d841994299@gmx.de>
Date: Tue, 19 Nov 2024 13:35:00 +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 v6 10/22] ACPI: platform_profile: Create class for ACPI
platform profile
Am 17.11.24 um 20:11 schrieb Armin Wolf:
> Am 09.11.24 um 05:41 schrieb Mario Limonciello:
>
>> When registering a platform profile handler create a class device
>> that will allow changing a single platform profile handler.
>>
>> The class and sysfs group are no longer needed when the platform profile
>> core is a module and unloaded, so remove them at that time as well.
>>
>> Tested-by: Mark Pearson <mpearson-lenovo@...ebb.ca>
>> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
>> ---
>> v6:
>> * Catch failures in ida_alloc
>> * Use 4th argument of device_create instead of dev_set_drvdata()
>> * Squash unregister patch
>> * Add module init callback
>> * Move class creation to module init
>> * Update visibility based on group presence
>> * Add back parent device
>> v5:
>> * Use ida instead of idr
>> * Use device_unregister instead of device_destroy()
>> * MKDEV (0, 0)
>> ---
>> drivers/acpi/platform_profile.c | 88 ++++++++++++++++++++++++++++++--
>> include/linux/platform_profile.h | 2 +
>> 2 files changed, 85 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/acpi/platform_profile.c
>> b/drivers/acpi/platform_profile.c
>> index 32affb75e782d..ef6af2c655524 100644
>> --- a/drivers/acpi/platform_profile.c
>> +++ b/drivers/acpi/platform_profile.c
>> @@ -5,6 +5,7 @@
>> #include <linux/acpi.h>
>> #include <linux/bits.h>
>> #include <linux/init.h>
>> +#include <linux/kdev_t.h>
>> #include <linux/mutex.h>
>> #include <linux/platform_profile.h>
>> #include <linux/sysfs.h>
>> @@ -22,6 +23,12 @@ static const char * const profile_names[] = {
>> };
>> static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST);
>>
>> +static DEFINE_IDA(platform_profile_ida);
>> +
>> +static const struct class platform_profile_class = {
>> + .name = "platform-profile",
>> +};
>> +
>> static ssize_t platform_profile_choices_show(struct device *dev,
>> struct device_attribute *attr,
>> char *buf)
>> @@ -105,8 +112,25 @@ static struct attribute
>> *platform_profile_attrs[] = {
>> NULL
>> };
>>
>> +static int profile_class_registered(struct device *dev, const void
>> *data)
>> +{
>> + return 1;
>> +}
>> +
>> +static umode_t profile_class_is_visible(struct kobject *kobj, struct
>> attribute *attr, int idx)
>> +{
>> + if (!class_find_device(&platform_profile_class, NULL, NULL,
>> profile_class_registered))
>> + return 0;
>> + if (attr == &dev_attr_platform_profile_choices.attr)
>> + return 0444;
>> + if (attr == &dev_attr_platform_profile.attr)
>> + return 0644;
>> + return 0;
>> +}
>> +
>> static const struct attribute_group platform_profile_group = {
>> - .attrs = platform_profile_attrs
>> + .attrs = platform_profile_attrs,
>> + .is_visible = profile_class_is_visible,
>> };
>>
>> void platform_profile_notify(struct platform_profile_handler *pprof)
>> @@ -123,6 +147,9 @@ int platform_profile_cycle(void)
>> enum platform_profile_option next;
>> int err;
>>
>> + if (!class_is_registered(&platform_profile_class))
>> + return -ENODEV;
>
> This check is pointless since the platform profile class will always
> be registered during module initialization.
> Please remove it.
>
>> +
>> scoped_cond_guard(mutex_intr, return -ERESTARTSYS,
>> &profile_lock) {
>> if (!cur_profile)
>> return -ENODEV;
>> @@ -164,25 +191,76 @@ int platform_profile_register(struct
>> platform_profile_handler *pprof)
>> if (cur_profile)
>> return -EEXIST;
>>
>> - err = sysfs_create_group(acpi_kobj, &platform_profile_group);
>> - if (err)
>> - return err;
>> + /* create class interface for individual handler */
>> + pprof->minor = ida_alloc(&platform_profile_ida, GFP_KERNEL);
>> + if (pprof->minor < 0)
>> + return pprof->minor;
>> + pprof->class_dev = device_create(&platform_profile_class,
>> pprof->dev,
>> + MKDEV(0, 0), pprof, "platform-profile-%d",
>> + pprof->minor);
>> + if (IS_ERR(pprof->class_dev)) {
>> + err = PTR_ERR(pprof->class_dev);
>> + goto cleanup_ida;
>> + }
>>
>> cur_profile = pprof;
>> +
>> + err = sysfs_update_group(acpi_kobj, &platform_profile_group);
>> + if (err)
>> + goto cleanup_cur;
>> +
>> return 0;
>> +
>> +cleanup_cur:
>> + cur_profile = NULL;
>> + device_unregister(pprof->class_dev);
>> +
>> +cleanup_ida:
>> + ida_free(&platform_profile_ida, pprof->minor);
>> +
>> + return err;
>> }
>> EXPORT_SYMBOL_GPL(platform_profile_register);
>>
>> int platform_profile_remove(struct platform_profile_handler *pprof)
>> {
>> + int id;
>> guard(mutex)(&profile_lock);
>>
>> - sysfs_remove_group(acpi_kobj, &platform_profile_group);
>> + id = pprof->minor;
>> + device_unregister(pprof->class_dev);
>> + ida_free(&platform_profile_ida, id);
>> +
>> cur_profile = NULL;
>> +
>> + sysfs_update_group(acpi_kobj, &platform_profile_group);
>> +
>> return 0;
>> }
>> EXPORT_SYMBOL_GPL(platform_profile_remove);
>>
>> +static int __init platform_profile_init(void)
>> +{
>> + int err;
>> +
>> + err = class_register(&platform_profile_class);
>> + if (err)
>> + return err;
>> +
>> + err = sysfs_create_group(acpi_kobj, &platform_profile_group);
>> + if (err)
>> + class_unregister(&platform_profile_class);
>> +
>> + return err;
>> +}
>
> Please use a blank line after function/struct/union/enum declarations.
>
> Apart from those minor issues the patch looks quite nice, so with
> those issues being fixed:
>
> Reviewed-by: Armin Wolf <W_Armin@....de>
>
>> +static void __exit platform_profile_exit(void)
>> +{
>> + class_unregister(&platform_profile_class);
>> + sysfs_remove_group(acpi_kobj, &platform_profile_group);
I just noticed that the legacy sysfs group needs to be removed before the class, otherwise
there might be a short time window during module exit where the legacy sysfs interface might
try to use the already unregistered class.
Thanks,
Armin Wolf
>> +}
>> +module_init(platform_profile_init);
>> +module_exit(platform_profile_exit);
>> +
>> MODULE_AUTHOR("Mark Pearson <markpearson@...ovo.com>");
>> MODULE_DESCRIPTION("ACPI platform profile sysfs interface");
>> MODULE_LICENSE("GPL");
>> diff --git a/include/linux/platform_profile.h
>> b/include/linux/platform_profile.h
>> index 8ec0b8da56db5..a888fd085c513 100644
>> --- a/include/linux/platform_profile.h
>> +++ b/include/linux/platform_profile.h
>> @@ -29,6 +29,8 @@ enum platform_profile_option {
>> struct platform_profile_handler {
>> const char *name;
>> struct device *dev;
>> + struct device *class_dev;
>> + int minor;
>> unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
>> int (*profile_get)(struct platform_profile_handler *pprof,
>> enum platform_profile_option *profile);
>
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