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

[Wen Jiang]

On Tue, 2 Jun 2026 at 01:34, Uladzislau Rezki <urezki at gmail.com> wrote:
>
> 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 <jiangwen6 at xiaomi.com>
> > Tested-by: Xueyuan Chen <xueyuan.chen21 at gmail.com>
> > ---
> >  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

Make sense, will split it, the steps/loops refactoring will move into patch 4.

Thanks,
Wen