> - struct page *page = migration_entry_to_page(entry);
> + struct page *page = pfn_to_page(swp_offset(entry));
I wonder if keeping a single special_entry_to_page() helper would still
me a useful. But I'm not entirely sure. There are also two more open
coded copies of this in the THP migration code.
> -#define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
> -#define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
> +#define free_swap_and_cache(e) is_special_entry(e)
> +#define swapcache_prepare(e) is_special_entry(e)
Staring at this I'm really, really confused at what this is doing.
Looking a little closer these are the !CONFIG_SWAP stubs, but it could
probably use a comment or two.
> } else if (is_migration_entry(entry)) {
> - page = migration_entry_to_page(entry);
> + page = pfn_to_page(swp_offset(entry));
>
> rss[mm_counter(page)]++;
>
> @@ -737,7 +737,7 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
> set_pte_at(src_mm, addr, src_pte, pte);
> }
> } else if (is_device_private_entry(entry)) {
> - page = device_private_entry_to_page(entry);
> + page = pfn_to_page(swp_offset(entry));
>
> /*
> * Update rss count even for unaddressable pages, as
> @@ -1274,7 +1274,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
>
> entry = pte_to_swp_entry(ptent);
> if (is_device_private_entry(entry)) {
> - struct page *page = device_private_entry_to_page(entry);
> + struct page *page = pfn_to_page(swp_offset(entry));
>
> if (unlikely(details && details->check_mapping)) {
> /*
> @@ -1303,7 +1303,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
> else if (is_migration_entry(entry)) {
> struct page *page;
>
> - page = migration_entry_to_page(entry);
> + page = pfn_to_page(swp_offset(entry));
> rss[mm_counter(page)]--;
> }
> if (unlikely(!free_swap_and_cache(entry)))
> @@ -3271,7 +3271,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> migration_entry_wait(vma->vm_mm, vmf->pmd,
> vmf->address);
> } else if (is_device_private_entry(entry)) {
> - vmf->page = device_private_entry_to_page(entry);
> + vmf->page = pfn_to_page(swp_offset(entry));
> ret = vmf->page->pgmap->ops->migrate_to_ram(vmf);
> } else if (is_hwpoison_entry(entry)) {
> ret = VM_FAULT_HWPOISON;
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 20ca887ea769..72adcc3d8f5b 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -321,7 +321,7 @@ void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
> if (!is_migration_entry(entry))
> goto out;
>
> - page = migration_entry_to_page(entry);
> + page = pfn_to_page(swp_offset(entry));
>
> /*
> * Once page cache replacement of page migration started, page_count
> @@ -361,7 +361,7 @@ void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd)
> ptl = pmd_lock(mm, pmd);
> if (!is_pmd_migration_entry(*pmd))
> goto unlock;
> - page = migration_entry_to_page(pmd_to_swp_entry(*pmd));
> + page = pfn_to_page(swp_offset(pmd_to_swp_entry(*pmd)));
> if (!get_page_unless_zero(page))
> goto unlock;
> spin_unlock(ptl);
> @@ -2437,7 +2437,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
> if (!is_device_private_entry(entry))
> goto next;
>
> - page = device_private_entry_to_page(entry);
> + page = pfn_to_page(swp_offset(entry));
> if (!(migrate->flags &
> MIGRATE_VMA_SELECT_DEVICE_PRIVATE) ||
> page->pgmap->owner != migrate->pgmap_owner)
> diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
> index 86e3a3688d59..34230d08556a 100644
> --- a/mm/page_vma_mapped.c
> +++ b/mm/page_vma_mapped.c
> @@ -96,7 +96,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw)
> if (!is_migration_entry(entry))
> return false;
>
> - pfn = migration_entry_to_pfn(entry);
> + pfn = swp_offset(entry);
> } else if (is_swap_pte(*pvmw->pte)) {
> swp_entry_t entry;
>
> @@ -105,7 +105,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw)
> if (!is_device_private_entry(entry))
> return false;
>
> - pfn = device_private_entry_to_pfn(entry);
> + pfn = swp_offset(entry);
> } else {
> if (!pte_present(*pvmw->pte))
> return false;
> @@ -200,7 +200,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
> if (is_migration_entry(pmd_to_swp_entry(*pvmw->pmd))) {
> swp_entry_t entry = pmd_to_swp_entry(*pvmw->pmd);
>
> - if (migration_entry_to_page(entry) != page)
> + if (pfn_to_page(swp_offset(entry)) != page)
> return not_found(pvmw);
> return true;
> }
> --
> 2.20.1
>
---end quoted text---
