Re: [PATCH v1 4/5] s390/uv: update PG_arch_1 comment

[Claudio Imbrenda]

On Thu,  4 Apr 2024 18:36:41 +0200
David Hildenbrand <david@xxxxxxxxxx> wrote:

> We removed the usage of PG_arch_1 for page tables in commit
> a51324c430db ("s390/cmma: rework no-dat handling").
> 
> Let's update the comment in UV to reflect that.
> 
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>

Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>

> ---
>  arch/s390/kernel/uv.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
> index 9c0113b26735..76fc61333fae 100644
> --- a/arch/s390/kernel/uv.c
> +++ b/arch/s390/kernel/uv.c
> @@ -471,13 +471,12 @@ int arch_make_page_accessible(struct page *page)
>  		return 0;
>  
>  	/*
> -	 * PG_arch_1 is used in 3 places:
> -	 * 1. for kernel page tables during early boot
> -	 * 2. for storage keys of huge pages and KVM
> -	 * 3. As an indication that this small folio might be secure. This can
> +	 * PG_arch_1 is used in 2 places:
> +	 * 1. for storage keys of hugetlb folios and KVM
> +	 * 2. As an indication that this small folio might be secure. This can
>  	 *    overindicate, e.g. we set the bit before calling
>  	 *    convert_to_secure.
> -	 * As secure pages are never huge, all 3 variants can co-exists.
> +	 * As secure pages are never large folios, both variants can co-exists.
>  	 */
>  	if (!test_bit(PG_arch_1, &folio->flags))
>  		return 0;