mm: fix handling PTE-mapped THPs in page_idle_clear_pte_refs()

For PTE-mapped THP page_check_address_transhuge() is not adequate: it
cannot find all relevant PTEs, only the first one.i

Let's switch it to page_vma_mapped_walk().

I don't think it's subject for stable@: it's not fatal.

Link: http://lkml.kernel.org/r/20170129173858.45174-5-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 17 deletions

diff --git a/mm/page_idle.c b/mm/page_idle.c
index ae11aa914e55..b0ee56c56b58 100644
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -54,27 +54,27 @@ static int page_idle_clear_pte_refs_one(struct page *page,
                                         struct vm_area_struct *vma,
                                         unsigned long addr, void *arg)
 {
-        struct mm_struct *mm = vma->vm_mm;
-        pmd_t *pmd;
-        pte_t *pte;
-        spinlock_t *ptl;
+        struct page_vma_mapped_walk pvmw = {
+                .page = page,
+                .vma = vma,
+                .address = addr,
+        };
         bool referenced = false;
 
-        if (!page_check_address_transhuge(page, mm, addr, &pmd, &pte, &ptl))
-                return SWAP_AGAIN;
-
-        if (pte) {
-                referenced = ptep_clear_young_notify(vma, addr, pte);
-                pte_unmap(pte);
-        } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
-                referenced = pmdp_clear_young_notify(vma, addr, pmd);
-        } else {
-                /* unexpected pmd-mapped page? */
-                WARN_ON_ONCE(1);
+        while (page_vma_mapped_walk(&pvmw)) {
+                addr = pvmw.address;
+                if (pvmw.pte) {
+                        referenced = ptep_clear_young_notify(vma, addr,
+                                        pvmw.pte);
+                } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
+                        referenced = pmdp_clear_young_notify(vma, addr,
+                                        pvmw.pmd);
+                } else {
+                        /* unexpected pmd-mapped page? */
+                        WARN_ON_ONCE(1);
+                }
         }
 
-        spin_unlock(ptl);
-
         if (referenced) {
                 clear_page_idle(page);
                 /*