Re: [PATCH v4 04/13] mm/debug_vm_pgtables/hugevmap: Use the arch helper to identify huge vmap support.

[Christophe Leroy <christophe.leroy@xxxxxxxxxx>]

Le 02/09/2020 à 13:42, Aneesh Kumar K.V a écrit :
> ppc64 supports huge vmap only with radix translation. Hence use arch helper
> to determine the huge vmap support.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
> ---
>   mm/debug_vm_pgtable.c | 14 ++++++++++++--
>   1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index 00649b47f6e0..4c73e63b4ceb 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -28,6 +28,7 @@
>   #include <linux/swapops.h>
>   #include <linux/start_kernel.h>
>   #include <linux/sched/mm.h>
> +#include <linux/io.h>
>   #include <asm/pgalloc.h>
>   #include <asm/tlbflush.h>
>   
> @@ -206,11 +207,12 @@ static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
>   	WARN_ON(!pmd_leaf(pmd));
>   }
>   
> +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
>   static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
>   {
>   	pmd_t pmd;
>   
> -	if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP))
> +	if (!arch_ioremap_pmd_supported())

What about moving ioremap_pmd_enabled() from mm/ioremap.c to some .h, 
and using it ?
As ioremap_pmd_enabled() is defined at all time, no need of #ifdef

>   		return;
>   
>   	pr_debug("Validating PMD huge\n");
> @@ -224,6 +226,9 @@ static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
>   	pmd = READ_ONCE(*pmdp);
>   	WARN_ON(!pmd_none(pmd));
>   }
> +#else /* CONFIG_HAVE_ARCH_HUGE_VMAP */
> +static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot) { }
> +#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
>   
>   static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
>   {
> @@ -320,11 +325,12 @@ static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot)
>   	WARN_ON(!pud_leaf(pud));
>   }
>   
> +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
>   static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
>   {
>   	pud_t pud;
>   
> -	if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP))
> +	if (!arch_ioremap_pud_supported())

What about moving ioremap_pud_enabled() from mm/ioremap.c to some .h, 
and using it ?
As ioremap_pud_enabled() is defined at all time, no need of #ifdef

>   		return;
>   
>   	pr_debug("Validating PUD huge\n");
> @@ -338,6 +344,10 @@ static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
>   	pud = READ_ONCE(*pudp);
>   	WARN_ON(!pud_none(pud));
>   }
> +#else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
> +static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot) { }
> +#endif /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
> +
>   #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
>   static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { }
>   static void __init pud_advanced_tests(struct mm_struct *mm,

Christophe