Re: [PATCH v3 01/11] mm/huge_memory: move more common code into insert_pmd()

[Lance Yang <lance.yang@xxxxxxxxx>]

On 2025/8/11 19:26, 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>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
> Reviewed-by: Wei Yang <richard.weiyang@xxxxxxxxx>
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Nice. Feel free to add:

Reviewed-by: Lance Yang <lance.yang@xxxxxxxxx>

Thanks,
Lance

> ---
>   mm/huge_memory.c | 72 ++++++++++++++++--------------------------------
>   1 file changed, 24 insertions(+), 48 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 2b4ea5a2ce7d2..5314a89d676f1 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1379,15 +1379,25 @@ struct folio_or_pfn {
>         bool is_folio;
>   };
>   
> -static int insert_pmd(struct vm_area_struct *vma, unsigned long addr,
> +static vm_fault_t insert_pmd(struct vm_area_struct *vma, unsigned long addr,
>                 pmd_t *pmd, struct folio_or_pfn fop, pgprot_t prot,
> -               bool write, pgtable_t pgtable)
> +               bool write)
>   {
>         struct mm_struct *mm = vma->vm_mm;
> +       pgtable_t pgtable = NULL;
> +       spinlock_t *ptl;
>         pmd_t entry;
>   
> -	lockdep_assert_held(pmd_lockptr(mm, pmd));
> +       if (addr < vma->vm_start || addr >= vma->vm_end)
> +               return VM_FAULT_SIGBUS;
>   
> +	if (arch_needs_pgtable_deposit()) {
> +               pgtable = pte_alloc_one(vma->vm_mm);
> +               if (!pgtable)
> +                       return VM_FAULT_OOM;
> +       }
> +
> +       ptl = pmd_lock(mm, pmd);
>         if (!pmd_none(*pmd)) {
>                 const unsigned long pfn = fop.is_folio ? folio_pfn(fop.folio) :
>                                           fop.pfn;
> @@ -1395,15 +1405,14 @@ static int insert_pmd(struct vm_area_struct *vma, 
> unsigned long addr,
>                 if (write) {
>                         if (pmd_pfn(*pmd) != pfn) {
>                                 WARN_ON_ONCE(!is_huge_zero_pmd(*pmd));
> -                               return -EEXIST;
> +                               goto out_unlock;
>                         }
>                         entry = pmd_mkyoung(*pmd);
>                         entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
>                         if (pmdp_set_access_flags(vma, addr, pmd, entry, 1))
>                                 update_mmu_cache_pmd(vma, addr, pmd);
>                 }
> -
> -               return -EEXIST;
> +               goto out_unlock;
>         }
>   
>   	if (fop.is_folio) {
> @@ -1424,11 +1433,17 @@ static int insert_pmd(struct vm_area_struct *vma, 
> unsigned long addr,
>         if (pgtable) {
>                 pgtable_trans_huge_deposit(mm, pmd, pgtable);
>                 mm_inc_nr_ptes(mm);
> +               pgtable = NULL;
>         }
>   
>   	set_pmd_at(mm, addr, pmd, entry);
>         update_mmu_cache_pmd(vma, addr, pmd);
> -       return 0;
> +
> +out_unlock:
> +       spin_unlock(ptl);
> +       if (pgtable)
> +               pte_free(mm, pgtable);
> +       return VM_FAULT_NOPAGE;
>   }
>   
>   /**
> @@ -1450,9 +1465,6 @@ vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, 
> unsigned long pfn,
>         struct folio_or_pfn fop = {
>                 .pfn = pfn,
>         };
> -       pgtable_t pgtable = NULL;
> -       spinlock_t *ptl;
> -       int error;
>   
>   	/*
>          * If we had pmd_special, we could avoid all these restrictions,
> @@ -1464,25 +1476,9 @@ vm_fault_t vmf_insert_pfn_pmd(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;
> -
> -       if (arch_needs_pgtable_deposit()) {
> -               pgtable = pte_alloc_one(vma->vm_mm);
> -               if (!pgtable)
> -                       return VM_FAULT_OOM;
> -       }
> -
>         pfnmap_setup_cachemode_pfn(pfn, &pgprot);
>   
> -	ptl = pmd_lock(vma->vm_mm, vmf->pmd);
> -       error = insert_pmd(vma, addr, vmf->pmd, fop, pgprot, write,
> -                          pgtable);
> -       spin_unlock(ptl);
> -       if (error && pgtable)
> -               pte_free(vma->vm_mm, pgtable);
> -
> -       return VM_FAULT_NOPAGE;
> +       return insert_pmd(vma, addr, vmf->pmd, fop, pgprot, write);
>   }
>   EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd);
>   
> @@ -1491,35 +1487,15 @@ vm_fault_t vmf_insert_folio_pmd(struct vm_fault *vmf, struct folio *folio,
>   {
>         struct vm_area_struct *vma = vmf->vma;
>         unsigned long addr = vmf->address & PMD_MASK;
> -       struct mm_struct *mm = vma->vm_mm;
>         struct folio_or_pfn fop = {
>                 .folio = folio,
>                 .is_folio = true,
>         };
> -       spinlock_t *ptl;
> -       pgtable_t pgtable = NULL;
> -       int error;
> -
> -       if (addr < vma->vm_start || addr >= vma->vm_end)
> -               return VM_FAULT_SIGBUS;
>   
>   	if (WARN_ON_ONCE(folio_order(folio) != PMD_ORDER))
>                 return VM_FAULT_SIGBUS;
>   
> -	if (arch_needs_pgtable_deposit()) {
> -               pgtable = pte_alloc_one(vma->vm_mm);
> -               if (!pgtable)
> -                       return VM_FAULT_OOM;
> -       }
> -
> -       ptl = pmd_lock(mm, vmf->pmd);
> -       error = insert_pmd(vma, addr, vmf->pmd, fop, vma->vm_page_prot,
> -                          write, pgtable);
> -       spin_unlock(ptl);
> -       if (error && pgtable)
> -               pte_free(mm, pgtable);
> -
> -       return VM_FAULT_NOPAGE;
> +       return insert_pmd(vma, addr, vmf->pmd, fop, vma->vm_page_prot, write);
>   }
>   EXPORT_SYMBOL_GPL(vmf_insert_folio_pmd);
>