Re: [PATCH v9 06/10] mm/vmalloc: extract vmap_set_ptes() to consolidate PTE mapping logic

[Uladzislau Rezki]

On Thu, Oct 01, 2026 at 03:58:21PM +0800, Wen Jiang wrote:
> On Wed, 30 Sept 2026 at 22:39, Uladzislau Rezki <urezki@xxxxxxxxx> wrote:
> >
> > On Wed, Sep 23, 2026 at 02:28:28PM +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.
> > >
> > > No functional change.
> > >
> > > Signed-off-by: Wen Jiang <jiangwen6@xxxxxxxxxx>
> > > Tested-by: Xueyuan Chen <xueyuan.chen21@xxxxxxxxx>
> > > Tested-by: Leo Yan <leo.yan@xxxxxxx>
> > > ---
> > >  mm/vmalloc.c | 36 +++++++++++++++++++++++++++---------
> > >  1 file changed, 27 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> > > index fb757d95bde25..d475e52110e4a 100644
> > > --- a/mm/vmalloc.c
> > > +++ b/mm/vmalloc.c
> > > @@ -92,6 +92,29 @@ struct vfree_deferred {
> > >  static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred);
> > >
> > >  /*** Page table manipulation functions ***/
> > > +
> > > +/*
> > > + * Try contiguous mappings at the PTE level for arches which support them, and if
> > > + * requested by the caller. Fall back to PAGE_SIZE mappings otherwise.
> > > + *
> > > + * Return: mapping size.
> > > + */
> > > +static __always_inline unsigned long vmap_set_ptes(pte_t *ptep,
> > > +             unsigned long addr, unsigned long end, u64 pfn,
> > > +             pgprot_t prot, unsigned int max_page_shift)
> > > +{
> > > +     unsigned long size;
> > > +
> > > +     size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift);
> > > +     if (size != PAGE_SIZE) {
> > > +             pte_set_huge(ptep, addr, PFN_PHYS(pfn), prot, size);
> > > +             return size;
> > > +     }
> > > +
> > > +     set_pte_at(&init_mm, addr, ptep, 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)
> > > @@ -100,6 +123,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
> > >       u64 pfn;
> > >       struct page *page;
> > >       unsigned long size;
> > > +     unsigned int steps;
> > >
> > >       if (WARN_ON_ONCE(!PAGE_ALIGNED(end - addr)))
> > >               return -EINVAL;
> > > @@ -120,15 +144,9 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
> > >                       BUG();
> > >               }
> > >
> > > -             size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift);
> > > -             if (size != PAGE_SIZE) {
> > > -                     pte_set_huge(pte, addr, PFN_PHYS(pfn), prot, size);
> > > -                     pfn += PFN_DOWN(size);
> > > -                     continue;
> > > -             }
> > > -             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);
> > >
> > #define PFN_DOWN(x)     ((x) >> PAGE_SHIFT) - how many pages covers the size.
> > Replace steps by nr_pages or nr_ptes?
> >
> 
> Agreed, I'll use nr_pages. Since vmap_pages_pte_range() in the next patch has
> the same "step = PFN_DOWN(size)" pattern, I'll rename it there too.
> 
Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>

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Uladzislau Rezki