Subject: Re: [PATCH v3 3/6] mm/vmalloc: Extract vmap_set_ptes() to consolidate PTE mapping logic

From: Uladzislau Rezki <[email-masked]>
Date: Mon, 1 Jun 2026 19:34:23 +0200

On Fri, May 22, 2026 at 01:31:43PM +0800, Wen Jiang wrote:
> Extract the common PTE mapping logic from vmap_pte_range() into a
> shared helper vmap_set_ptes(). This handles both CONT_PTE and regular
> PTE mappings in a single function, preparing for the next patch which
> will extend vmap_pages_pte_range() to also use this helper.
> 
> The #ifdef CONFIG_HUGETLB_PAGE guard is moved inside vmap_set_ptes(),
> so callers no longer need to handle the conditional compilation.
> 
> Signed-off-by: Wen Jiang <[email-masked]>
> Tested-by: Xueyuan Chen <[email-masked]>
> ---
>  mm/vmalloc.c | 49 ++++++++++++++++++++++++++++++++++---------------
>  1 file changed, 34 insertions(+), 15 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 2c2f74a07f396..53fd4ee460ea4 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -91,6 +91,35 @@ struct vfree_deferred {
>  static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred);
>  
>  /*** Page table manipulation functions ***/
> +
> +/*
> + * Set PTE mappings for the given PFN. Try CONT_PTE mappings first when
> + * supported, otherwise fall back to PAGE_SIZE mappings.
> + *
> + * Return: mapping size.
> + */
> +static __always_inline unsigned long vmap_set_ptes(pte_t *pte,
> +		unsigned long addr, unsigned long end, u64 pfn,
> +		pgprot_t prot, unsigned int max_page_shift)
> +{
> +#ifdef CONFIG_HUGETLB_PAGE
> +	if (max_page_shift > PAGE_SHIFT) {
> +		unsigned long size;
> +
> +		size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift);
> +		if (size != PAGE_SIZE) {
> +			pte_t entry = pfn_pte(pfn, prot);
> +
> +			entry = arch_make_huge_pte(entry, ilog2(size), 0);
> +			set_huge_pte_at(&init_mm, addr, pte, entry, size);
> +			return size;
> +		}
> +	}
> +#endif
> +	set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
> +	return PAGE_SIZE;
> +}
> +
>  static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
>  			phys_addr_t phys_addr, pgprot_t prot,
>  			unsigned int max_page_shift, pgtbl_mod_mask *mask)
> @@ -98,7 +127,8 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
>  	pte_t *pte;
>  	u64 pfn;
>  	struct page *page;
> -	unsigned long size = PAGE_SIZE;
> +	unsigned long size;
> +	unsigned int steps;
>  
>  	if (WARN_ON_ONCE(!PAGE_ALIGNED(end - addr)))
>  		return -EINVAL;
> @@ -119,20 +149,9 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
>  			BUG();
>  		}
>  
> -#ifdef CONFIG_HUGETLB_PAGE
> -		size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift);
> -		if (size != PAGE_SIZE) {
> -			pte_t entry = pfn_pte(pfn, prot);
> -
> -			entry = arch_make_huge_pte(entry, ilog2(size), 0);
> -			set_huge_pte_at(&init_mm, addr, pte, entry, size);
> -			pfn += PFN_DOWN(size);
> -			continue;
> -		}
> -#endif
> -		set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
> -		pfn++;
> -	} while (pte += PFN_DOWN(size), addr += size, addr != end);
> +		size = vmap_set_ptes(pte, addr, end, pfn, prot, max_page_shift);
> +		steps = PFN_DOWN(size);
> +	} while (pte += steps, pfn += steps, addr += size, addr != end);
>  
>  	lazy_mmu_mode_disable();
>  	*mask |= PGTBL_PTE_MODIFIED;
> -- 
> 2.34.1
> 
IMO, we should add just a helper with "no functional change" and second
patch will extend it.

Otherwise you added a helper which has already been slightly modified.

--
Uladzislau Rezki