linux-kernel - Re: [PATCH] s390/mm: Simplify gap clamping in mmap

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Message-ID: <Z68h0B6vFdfCbNpb@li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com>
Date: Fri, 14 Feb 2025 11:58:24 +0100
From: Alexander Gordeev <agordeev@...ux.ibm.com>
To: Qasim Ijaz <qasdev00@...il.com>
Cc: gerald.schaefer@...ux.ibm.com, hca@...ux.ibm.com, gor@...ux.ibm.com,
        borntraeger@...ux.ibm.com, svens@...ux.ibm.com,
        linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] s390/mm: Simplify gap clamping in mmap_base() using
 clamp()

On Tue, Feb 04, 2025 at 04:25:08PM +0000, Qasim Ijaz wrote:
> mmap_base() has logic to ensure that the variable "gap" stays within the 
> range defined by "gap_min" and "gap_max". Replace this with the clamp() 
> macro to shorten and simplify code.
> 
> Signed-off-by: Qasim Ijaz <qasdev00@...il.com>
> ---
>  arch/s390/mm/mmap.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
> index 76f376876e0d..a3d3e09a2828 100644
> --- a/arch/s390/mm/mmap.c
> +++ b/arch/s390/mm/mmap.c
> @@ -63,11 +63,7 @@ static inline unsigned long mmap_base(unsigned long rnd,
>  	 */
>  	gap_min = SZ_128M;
>  	gap_max = (STACK_TOP / 6) * 5;
> -
> -	if (gap < gap_min)
> -		gap = gap_min;
> -	else if (gap > gap_max)
> -		gap = gap_max;
> +	gap = clamp(gap, gap_min, gap_max);
>  
>  	return PAGE_ALIGN(STACK_TOP - gap - rnd);
>  }

Whenever possible I personally prefer branches over ternary operators.
But if one wants to clump it in one line, then gap_min and gap_max
are also redundant.

Thanks!