Re: [PATCH 1/6] platform/x86: firmware_attributes_class: Move include linux/device/class.h

[Armin Wolf <W_Armin@gmx.de>]

Am 04.01.25 um 08:20 schrieb Armin Wolf:

> Am 04.01.25 um 08:06 schrieb Thomas Weißschuh:
>
>> Hi,
>>
>> On 2025-01-04 07:55:15+0100, Armin Wolf wrote:
>>> Am 04.01.25 um 00:05 schrieb Thomas Weißschuh:
>>>
>>>> The header firmware_attributes_class.h uses 'struct class'. It should
>>>> also include the necessary dependency header.
>>> i like this patch series, but i would prefer that we do not expose
>>> the raw class through the header.
>>>
>>> Looking at the callers of fw_attributes_class_get(), everywhere the
>>> class value is used only to call:
>>>
>>>     device_create(fw_attr_class, NULL, MKDEV(0, 0), NULL, "%s",
>>> <driver name>);
>>>
>>> I suggest that we introduce two new functions for that:
>>>
>>>     struct device *firmware_attributes_device_register(struct device
>>> *parent, const char *name);
>>>
>>>     void firmware_attributes_device_unregister(struct device *dev);
>>>
>>> This would have three major benefits:
>>>
>>> - the raw class can be made internal
>>> - reduced code size
>>> - drivers would stop copying the flawed use of device_destroy()
>>>
>>> Regarding the use of device_destroy(): this is actually an error
>>> since device_destroy() cannot be
>>> reliably used when devt is not unique. Since all those drivers are
>>> setting devt to MKDEV(0, 0) this
>>> could result in a kernel panic should multiple firmware-attribute
>>> class devices exist at the same time.
>>>
>>> What do you think?
>> Completely agree. This is exactly what the "further improvements"
>> mentioned in the cover letter do.
>> And also add devm_firmware_attributes_device_register() and a custom
>> sysfs attribute type that makes the driver code much simplerr.
>>
>> But this will be some more work. Also the conversions of the drivers
>> will be harder and take longer, so we can't drop the raw exposed class
>> as easily and have to keep the "legacy" interface for a bit.
>
> Fair point. In this case the current approach should be fine.
>
>>> Thanks,
>>> Armin Wolf
>>>
>>>> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
>>>> ---
>>>>    drivers/platform/x86/firmware_attributes_class.c | 1 -
>>>>    drivers/platform/x86/firmware_attributes_class.h | 2 ++
>>>>    2 files changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/platform/x86/firmware_attributes_class.c
>>>> b/drivers/platform/x86/firmware_attributes_class.c
>>>> index
>>>> 182a07d8ae3dfa8925bb5b71a43d0219c3cf0fa0..cbc56e5db59283ba99ac0b915ac5fb2432afbdc9
>>>> 100644
>>>> --- a/drivers/platform/x86/firmware_attributes_class.c
>>>> +++ b/drivers/platform/x86/firmware_attributes_class.c
>>>> @@ -3,7 +3,6 @@
>>>>    /* Firmware attributes class helper module */
>>>>
>>>>    #include <linux/mutex.h>
>>>> -#include <linux/device/class.h>
>>>>    #include <linux/module.h>
>>>>    #include "firmware_attributes_class.h"
>>>>
>>>> diff --git a/drivers/platform/x86/firmware_attributes_class.h
>>>> b/drivers/platform/x86/firmware_attributes_class.h
>>>> index
>>>> 363c75f1ac1b89df879a8689b070e6b11d3bb7fd..8e0f47cfdf92eb4dc8722b7d8371916af0d84efa
>>>> 100644
>>>> --- a/drivers/platform/x86/firmware_attributes_class.h
>>>> +++ b/drivers/platform/x86/firmware_attributes_class.h
>>>> @@ -5,6 +5,8 @@
>>>>    #ifndef FW_ATTR_CLASS_H
>>>>    #define FW_ATTR_CLASS_H
>>>>
>>>> +#include <linux/device/class.h>
>
> I think it would make more sense to not include the complete class
> header and instead only
> define "struct class;" inside firmware_attributes_class.h.
>
> Thanks,
> Armin Wolf

Forget what i just said, we still need the header once we expose the class.

For the whole series:

Reviewed-by: Armin Wolf <W_Armin@gmx.de>

>
>>>> +
>>>>    int fw_attributes_class_get(const struct class **fw_attr_class);
>>>>    int fw_attributes_class_put(void);
>>>>
>>>>
>