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

Lorenzo Stoakes
2025-07-17T15:43:32Z

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@suse.de>
> Reviewed-by: Alistair Popple <apopple@nvidia.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>

LGTM:

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

> ---
> 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
>