[PATCH 06/12] mm: convert page_mkclean_one() to page_check_walk()

[Kirill A. Shutemov]

For consistency, it worth converting all page_check_address() to
page_check_walk(), so we could drop the former.

PMD handling here is future-proofing, we don't have users yet. ext4 with
huge pages will be the first.

Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
---
 mm/rmap.c | 66 +++++++++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 43 insertions(+), 23 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index 3bbf83b32553..41874a6f6cf5 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1017,34 +1017,54 @@ int page_referenced(struct page *page,
 static int page_mkclean_one(struct page *page, struct vm_area_struct *vma,
                            unsigned long address, void *arg)
 {
-       struct mm_struct *mm = vma->vm_mm;
-       pte_t *pte;
-       spinlock_t *ptl;
-       int ret = 0;
+       struct page_check_walk pcw = {
+               .page = page,
+               .vma = vma,
+               .address = address,
+               .flags = PAGE_CHECK_WALK_SYNC,
+       };
        int *cleaned = arg;
 
-       pte = page_check_address(page, mm, address, &ptl, 1);
-       if (!pte)
-               goto out;
-
-       if (pte_dirty(*pte) || pte_write(*pte)) {
-               pte_t entry;
+       while (page_check_walk(&pcw)) {
+               int ret = 0;
+               address = pcw.address;
+               if (pcw.pte) {
+                       pte_t entry;
+                       pte_t *pte = pcw.pte;
+
+                       if (!pte_dirty(*pte) && !pte_write(*pte))
+                               continue;
+
+                       flush_cache_page(vma, address, pte_pfn(*pte));
+                       entry = ptep_clear_flush(vma, address, pte);
+                       entry = pte_wrprotect(entry);
+                       entry = pte_mkclean(entry);
+                       set_pte_at(vma->vm_mm, address, pte, entry);
+                       ret = 1;
+               } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) {
+                       pmd_t *pmd = pcw.pmd;
+                       pmd_t entry;
+
+                       if (!pmd_dirty(*pmd) && !pmd_write(*pmd))
+                               continue;
+
+                       flush_cache_page(vma, address, page_to_pfn(page));
+                       entry = pmdp_huge_clear_flush(vma, address, pmd);
+                       entry = pmd_wrprotect(entry);
+                       entry = pmd_mkclean(entry);
+                       set_pmd_at(vma->vm_mm, address, pmd, entry);
+                       ret = 1;
+               } else {
+                       /* unexpected pmd-mapped page? */
+                       WARN_ON_ONCE(1);
+               }
 
-               flush_cache_page(vma, address, pte_pfn(*pte));
-               entry = ptep_clear_flush(vma, address, pte);
-               entry = pte_wrprotect(entry);
-               entry = pte_mkclean(entry);
-               set_pte_at(mm, address, pte, entry);
-               ret = 1;
+               if (ret) {
+                       mmu_notifier_invalidate_page(vma->vm_mm, address);
+                       (*cleaned)++;
+               }
        }
 
-       pte_unmap_unlock(pte, ptl);
-
-       if (ret) {
-               mmu_notifier_invalidate_page(mm, address);
-               (*cleaned)++;
-       }
-out:
        return SWAP_AGAIN;
 }
 
-- 
2.11.0