Re: [PATCH v5] staging: greybus: Constify gb_audio_module_type

From: Fabio M. De Francesco
Date: Sat Mar 16 2024 - 14:45:32 EST


On Saturday, 16 March 2024 19:24:21 CET Ayush Tiwari wrote:
> Constify static struct kobj_type gb_audio_module_type to prevent
> modification

I'm not yet convinced that being or not being const has much to do with
sharing data.

And next time please wait for other people to comment your versions. Wait a
day or two and then please delete everything from here...

> of data shared across many instances(instances here
> refer to multiple kobject instances being created, since this same
> gb_audio_module_type structure is used as a template for all audio
> manager module kobjs, it is effectively 'shared' across all these
> instances),

to here.

Thanks,

Fabio

> ensuring that the structure's usage is consistent and
> predictable throughout the driver and allowing the compiler to place
> it in read-only memory. The gb_audio_module_type structure is used
> when initializing and adding kobj instances to the kernel's object
> hierarchy. After adding const, any attempt to alter
> gb_audio_module_type in the code would raise a compile-time error.
> This enforcement ensures that the sysfs interface and operations for
> audio modules remain stable.
>
> Signed-off-by: Ayush Tiwari <ayushtiw0110@xxxxxxxxx>
>
> ---
> Changes in v5: added more details as per feedback.
>
> Changes in v4: added more details verifying the change.
>
> Changes in v3: added the message that verifies the change,
> as suggested by Julia
>
> Changes in v2: incorporated changes in commit message
> as suggested by Alison
> ---
> drivers/staging/greybus/audio_manager_module.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/greybus/audio_manager_module.c
> b/drivers/staging/greybus/audio_manager_module.c index
> 5f9dcbdbc191..4a4dfb42f50f 100644
> --- a/drivers/staging/greybus/audio_manager_module.c
> +++ b/drivers/staging/greybus/audio_manager_module.c
> @@ -144,7 +144,7 @@ static struct attribute
> *gb_audio_module_default_attrs[] = { };
> ATTRIBUTE_GROUPS(gb_audio_module_default);
>
> -static struct kobj_type gb_audio_module_type = {
> +static const struct kobj_type gb_audio_module_type = {
> .sysfs_ops = &gb_audio_module_sysfs_ops,
> .release = gb_audio_module_release,
> .default_groups = gb_audio_module_default_groups,