Re: [PATCH] mm: Use strtobool for param parsing

[Andrew Morton <akpm@linux-foundation.org>]

On Sun, 27 Feb 2022 18:10:39 +0000 "Dr. David Alan Gilbert" <linux@treblig.org> wrote:

> Use strtobool rather than open coding "on" and "off" parsing in
> mm/hugetlb_vmemmap.c and mm/page_table_check.c.
> 
> Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
> ---
>  mm/hugetlb_vmemmap.c  | 12 +-----------
>  mm/page_table_check.c | 10 +---------
>  2 files changed, 2 insertions(+), 20 deletions(-)
> 
> diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
> index c540c21e26f5b..919411386e547 100644
> --- a/mm/hugetlb_vmemmap.c
> +++ b/mm/hugetlb_vmemmap.c
> @@ -192,17 +192,7 @@ static int __init early_hugetlb_free_vmemmap_param(char *buf)
>  		return 0;
>  	}
>  
> -	if (!buf)
> -		return -EINVAL;
> -
> -	if (!strcmp(buf, "on"))
> -		hugetlb_free_vmemmap_enabled = true;
> -	else if (!strcmp(buf, "off"))
> -		hugetlb_free_vmemmap_enabled = false;
> -	else
> -		return -EINVAL;
> -
> -	return 0;
> +	return strtobool(buf, &hugetlb_free_vmemmap_enabled);
>  }
>  early_param("hugetlb_free_vmemmap", early_hugetlb_free_vmemmap_param);

This part falls afoul of the changes in
https://lkml.kernel.org/r/20211101031651.75851-3-songmuchun@bytedance.com

> diff --git a/mm/page_table_check.c b/mm/page_table_check.c
> index 3763bd077861a..2458281bff893 100644
> --- a/mm/page_table_check.c
> +++ b/mm/page_table_check.c
> @@ -23,15 +23,7 @@ EXPORT_SYMBOL(page_table_check_disabled);
>  
>  static int __init early_page_table_check_param(char *buf)
>  {
> -	if (!buf)
> -		return -EINVAL;
> -
> -	if (strcmp(buf, "on") == 0)
> -		__page_table_check_enabled = true;
> -	else if (strcmp(buf, "off") == 0)
> -		__page_table_check_enabled = false;
> -
> -	return 0;
> +	return strtobool(buf, &__page_table_check_enabled);
>  }

But this works OK.