Re: [PATCH] xen/bitmap: Drop unused headers

[Julien Grall <julien@xxxxxxx>]

Hi Andrew,

On 10/05/2025 14:12, Andrew Cooper wrote:
> Nothing in bitmap.h uses lib.h.  Reduce to just macros.h and string.h.  Drop
> types.h while at it, as it comes in through bitops.h
>
> cpumask.h and nodemask.h only include kernel.h to get container_of().  Move it
> into macros.h where it belongs.
The wording implies that container_of() will be moved as-is (barring 
coding style). However...
[...]

> -/**
> - * container_of - cast a member of a structure out to the containing structure
> - *
> - * @ptr:       the pointer to the member.
> - * @type:      the type of the container struct this is embedded in.
> - * @member:    the name of the member within the struct.
> - *
> - */
> -#define container_of(ptr, type, member) ({                      \
> -        typeof_field(type, member) *__mptr = (ptr);             \
> -        (type *)( (char *)__mptr - offsetof(type,member) );})
> -
I see the cast was switch from "char *" to ...

>   /**
>    * __struct_group() - Create a mirrored named and anonyomous struct
>    *
> diff --git a/xen/include/xen/macros.h b/xen/include/xen/macros.h
> index cd528fbdb127..58affb1588c5 100644
> --- a/xen/include/xen/macros.h
> +++ b/xen/include/xen/macros.h
> @@ -102,6 +102,19 @@
>    */
>   #define sizeof_field(type, member) sizeof(((type *)NULL)->member)
>   
> +/**
> + * container_of - cast a member of a structure out to the containing structure
> + *
> + * @ptr:       the pointer to the member.
> + * @type:      the type of the container struct this is embedded in.
> + * @member:    the name of the member within the struct.
> + */
> +#define container_of(ptr, type, member)                         \
> +    ({                                                          \
> +        typeof_field(type, member) *__mptr = (ptr);             \
> +        (type *)((void *)__mptr - offsetof(type, member));      \
... "void *". AFAICT, this is doesn't change anything. However, I think 
it is worth mentioning in the commit message to show this was intended.
With that:

Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

--
Julien Grall