[PATCH 2/7] arm64: hugetlb: Cleanup setup_hugepagesz

[mark.rutland@arm.com (Mark Rutland)]

On Tue, Mar 21, 2017 at 06:04:16PM +0000, Punit Agrawal wrote:
> From: Steve Capper <steve.capper@arm.com>
> 
> Replace a lot of if statements with switch and case labels to make it
> much clearer which huge page sizes are supported.
> 
> Also, we prevent PUD_SIZE from being used on systems not running with
> 4KB PAGE_SIZE. Before if one supplied PUD_SIZE in these circumstances,
> then unusuable huge page sizes would be in use.
> 
> Fixes: 084bd29810a5 ("ARM64: mm: HugeTLB support.")
> Cc: David Woods <dwoods@mellanox.com>
> Signed-off-by: Steve Capper <steve.capper@arm.com>
> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>

Reviewed-by: Mark Rutland <mark.rutland@arm.com>

I assume this'll get a cc stable to ensure backport.

Thanks,
Mark.

> ---
>  arch/arm64/mm/hugetlbpage.c | 26 +++++++++++++-------------
>  1 file changed, 13 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
> index a686f8705ef3..aacbe18e6640 100644
> --- a/arch/arm64/mm/hugetlbpage.c
> +++ b/arch/arm64/mm/hugetlbpage.c
> @@ -296,20 +296,20 @@ static __init int setup_hugepagesz(char *opt)
>  {
>  	unsigned long ps = memparse(opt, &opt);
>  
> -	if (ps == PMD_SIZE) {
> -		hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
> -	} else if (ps == PUD_SIZE) {
> -		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
> -	} else if (ps == (PAGE_SIZE * CONT_PTES)) {
> -		hugetlb_add_hstate(CONT_PTE_SHIFT);
> -	} else if (ps == (PMD_SIZE * CONT_PMDS)) {
> -		hugetlb_add_hstate((PMD_SHIFT + CONT_PMD_SHIFT) - PAGE_SHIFT);
> -	} else {
> -		hugetlb_bad_size();
> -		pr_err("hugepagesz: Unsupported page size %lu K\n", ps >> 10);
> -		return 0;
> +	switch (ps) {
> +#ifdef CONFIG_ARM64_4K_PAGES
> +	case PUD_SIZE:
> +#endif
> +	case PMD_SIZE * CONT_PMDS:
> +	case PMD_SIZE:
> +	case PAGE_SIZE * CONT_PTES:
> +		hugetlb_add_hstate(ilog2(ps) - PAGE_SHIFT);
> +		return 1;
>  	}
> -	return 1;
> +
> +	hugetlb_bad_size();
> +	pr_err("hugepagesz: Unsupported page size %lu K\n", ps >> 10);
> +	return 0;
>  }
>  __setup("hugepagesz=", setup_hugepagesz);
>  
> -- 
> 2.11.0
>