Re: [PATCH v2 2/9] mm/huge_memory: move more common code into insert_pud()

[Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>]

On Thu, Jul 17, 2025 at 01:52:05PM +0200, David Hildenbrand wrote:
> Let's clean it all further up.
>
> No functional change intended.
>
> Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
> Reviewed-by: Alistair Popple <apopple@xxxxxxxxxx>
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>

LGTM:

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>

> ---
>  mm/huge_memory.c | 36 +++++++++++++-----------------------
>  1 file changed, 13 insertions(+), 23 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 1178760d2eda4..849feacaf8064 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1518,25 +1518,30 @@ static pud_t maybe_pud_mkwrite(pud_t pud, struct 
> vm_area_struct *vma)
>       return pud;
>  }
>
> -static void insert_pud(struct vm_area_struct *vma, unsigned long addr,
> +static vm_fault_t insert_pud(struct vm_area_struct *vma, unsigned long addr,
>               pud_t *pud, struct folio_or_pfn fop, pgprot_t prot, bool write)
>  {
>       struct mm_struct *mm = vma->vm_mm;
> +     spinlock_t *ptl;
>       pud_t entry;
>
> +     if (addr < vma->vm_start || addr >= vma->vm_end)
> +             return VM_FAULT_SIGBUS;
> +
> +     ptl = pud_lock(mm, pud);
>       if (!pud_none(*pud)) {
>               const unsigned long pfn = fop.is_folio ? folio_pfn(fop.folio) :
>                                         fop.pfn;
>
>               if (write) {
>                       if (WARN_ON_ONCE(pud_pfn(*pud) != pfn))
> -                             return;
> +                             goto out_unlock;
>                       entry = pud_mkyoung(*pud);
>                       entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma);
>                       if (pudp_set_access_flags(vma, addr, pud, entry, 1))
>                               update_mmu_cache_pud(vma, addr, pud);
>               }
> -             return;
> +             goto out_unlock;
>       }
>
>       if (fop.is_folio) {
> @@ -1555,6 +1560,9 @@ static void insert_pud(struct vm_area_struct *vma, 
> unsigned long addr,
>       }
>       set_pud_at(mm, addr, pud, entry);
>       update_mmu_cache_pud(vma, addr, pud);
> +out_unlock:
> +     spin_unlock(ptl);
> +     return VM_FAULT_NOPAGE;
>  }
>
>  /**
> @@ -1576,7 +1584,6 @@ vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, 
> unsigned long pfn,
>       struct folio_or_pfn fop = {
>               .pfn = pfn,
>       };
> -     spinlock_t *ptl;
>
>       /*
>        * If we had pud_special, we could avoid all these restrictions,
> @@ -1588,16 +1595,9 @@ vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, 
> unsigned long pfn,
>                                               (VM_PFNMAP|VM_MIXEDMAP));
>       BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
>
> -     if (addr < vma->vm_start || addr >= vma->vm_end)
> -             return VM_FAULT_SIGBUS;
> -
>       pfnmap_setup_cachemode_pfn(pfn, &pgprot);
>
> -     ptl = pud_lock(vma->vm_mm, vmf->pud);
> -     insert_pud(vma, addr, vmf->pud, fop, pgprot, write);
> -     spin_unlock(ptl);
> -
> -     return VM_FAULT_NOPAGE;
> +     return insert_pud(vma, addr, vmf->pud, fop, pgprot, write);
>  }
>  EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud);
>
> @@ -1614,25 +1614,15 @@ vm_fault_t vmf_insert_folio_pud(struct vm_fault *vmf, 
> struct folio *folio,
>  {
>       struct vm_area_struct *vma = vmf->vma;
>       unsigned long addr = vmf->address & PUD_MASK;
> -     pud_t *pud = vmf->pud;
> -     struct mm_struct *mm = vma->vm_mm;
>       struct folio_or_pfn fop = {
>               .folio = folio,
>               .is_folio = true,
>       };
> -     spinlock_t *ptl;
> -
> -     if (addr < vma->vm_start || addr >= vma->vm_end)
> -             return VM_FAULT_SIGBUS;
>
>       if (WARN_ON_ONCE(folio_order(folio) != PUD_ORDER))
>               return VM_FAULT_SIGBUS;
>
> -     ptl = pud_lock(mm, pud);
> -     insert_pud(vma, addr, vmf->pud, fop, vma->vm_page_prot, write);
> -     spin_unlock(ptl);
> -
> -     return VM_FAULT_NOPAGE;
> +     return insert_pud(vma, addr, vmf->pud, fop, vma->vm_page_prot, write);
>  }
>  EXPORT_SYMBOL_GPL(vmf_insert_folio_pud);
>  #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
> --
> 2.50.1
>