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

[Armin Wolf]

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.

Hi,

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?

Thanks,
Armin Wolf

> Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
> ---
>   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>
> +
>   int fw_attributes_class_get(const struct class **fw_attr_class);
>   int fw_attributes_class_put(void);