khugepaged: collapse_pte_mapped_thp() flush the right range

[mirror_ubuntu-focal-kernel.git] / mm / khugepaged.c

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 0a1b4b484ac5b4a0eed5e5148f04849d9e09607b..e98937c8bed05ba315c66f07ef22a4184bf4c88c 100644 (file)
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -876,6 +876,9 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
                return SCAN_ADDRESS_RANGE;
        if (!hugepage_vma_check(vma, vma->vm_flags))
                return SCAN_VMA_CHECK;
+       /* Anon VMA expected */
+       if (!vma->anon_vma || vma->vm_ops)
+               return SCAN_VMA_CHECK;
        return 0;
 }
 
@@ -1028,12 +1031,13 @@ static void collapse_huge_page(struct mm_struct *mm,
 
        anon_vma_lock_write(vma->anon_vma);
 
-       pte = pte_offset_map(pmd, address);
-       pte_ptl = pte_lockptr(mm, pmd);
-
        mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm,
                                address, address + HPAGE_PMD_SIZE);
        mmu_notifier_invalidate_range_start(&range);
+
+       pte = pte_offset_map(pmd, address);
+       pte_ptl = pte_lockptr(mm, pmd);
+
        pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */
        /*
         * After this gup_fast can't run anymore. This also removes
@@ -1380,7 +1384,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
 
        /* step 4: collapse pmd */
        ptl = pmd_lock(vma->vm_mm, pmd);
-       _pmd = pmdp_collapse_flush(vma, addr, pmd);
+       _pmd = pmdp_collapse_flush(vma, haddr, pmd);
        spin_unlock(ptl);
        mm_dec_nr_ptes(mm);
        pte_free(mm, pmd_pgtable(_pmd));
@@ -1601,17 +1605,6 @@ static void collapse_file(struct mm_struct *mm,
                                        result = SCAN_FAIL;
                                        goto xa_unlocked;
                                }
-                       } else if (!PageUptodate(page)) {
-                               xas_unlock_irq(&xas);
-                               wait_on_page_locked(page);
-                               if (!trylock_page(page)) {
-                                       result = SCAN_PAGE_LOCK;
-                                       goto xa_unlocked;
-                               }
-                               get_page(page);
-                       } else if (PageDirty(page)) {
-                               result = SCAN_FAIL;
-                               goto xa_locked;
                        } else if (trylock_page(page)) {
                                get_page(page);
                                xas_unlock_irq(&xas);
@@ -1626,7 +1619,12 @@ static void collapse_file(struct mm_struct *mm,
                 * without racing with truncate.
                 */
                VM_BUG_ON_PAGE(!PageLocked(page), page);
-               VM_BUG_ON_PAGE(!PageUptodate(page), page);
+
+               /* make sure the page is up to date */
+               if (unlikely(!PageUptodate(page))) {
+                       result = SCAN_FAIL;
+                       goto out_unlock;
+               }
 
                /*
                 * If file was truncated then extended, or hole-punched, before
@@ -1642,6 +1640,16 @@ static void collapse_file(struct mm_struct *mm,
                        goto out_unlock;
                }
 
+               if (!is_shmem && PageDirty(page)) {
+                       /*
+                        * khugepaged only works on read-only fd, so this
+                        * page is dirty because it hasn't been flushed
+                        * since first write.
+                        */
+                       result = SCAN_FAIL;
+                       goto out_unlock;
+               }
+
                if (isolate_lru_page(page)) {
                        result = SCAN_DEL_PAGE_LRU;
                        goto out_unlock;
@@ -1650,6 +1658,7 @@ static void collapse_file(struct mm_struct *mm,
                if (page_has_private(page) &&
                    !try_to_release_page(page, GFP_KERNEL)) {
                        result = SCAN_PAGE_HAS_PRIVATE;
+                       putback_lru_page(page);
                        goto out_unlock;
                }