Merge tag 'locking-core-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6-microblaze.git] / mm / rmap.c

diff --git a/mm/rmap.c b/mm/rmap.c
index 31b2932..08c56aa 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -28,12 +28,12 @@
  *           hugetlb_fault_mutex (hugetlbfs specific page fault mutex)
  *           anon_vma->rwsem
  *             mm->page_table_lock or pte_lock
- *               pgdat->lru_lock (in mark_page_accessed, isolate_lru_page)
  *               swap_lock (in swap_duplicate, swap_info_get)
  *                 mmlist_lock (in mmput, drain_mmlist and others)
  *                 mapping->private_lock (in __set_page_dirty_buffers)
- *                   mem_cgroup_{begin,end}_page_stat (memcg->move_lock)
+ *                   lock_page_memcg move_lock (in __set_page_dirty_buffers)
  *                     i_pages lock (widely used)
+ *                       lruvec->lru_lock (in lock_page_lruvec_irq)
  *                 inode->i_lock (in set_page_dirty's __mark_inode_dirty)
  *                 bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty)
  *                   sb_lock (within inode_lock in fs/fs-writeback.c)
@@ -1054,8 +1054,14 @@ static void __page_set_anon_rmap(struct page *page,
        if (!exclusive)
                anon_vma = anon_vma->root;
 
+       /*
+        * page_idle does a lockless/optimistic rmap scan on page->mapping.
+        * Make sure the compiler doesn't split the stores of anon_vma and
+        * the PAGE_MAPPING_ANON type identifier, otherwise the rmap code
+        * could mistake the mapping for a struct address_space and crash.
+        */
        anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
-       page->mapping = (struct address_space *) anon_vma;
+       WRITE_ONCE(page->mapping, (struct address_space *) anon_vma);
        page->index = linear_page_index(vma, address);
 }
 
@@ -1533,15 +1539,6 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
                        goto discard;
                }
 
-               if (!(flags & TTU_IGNORE_ACCESS)) {
-                       if (ptep_clear_flush_young_notify(vma, address,
-                                               pvmw.pte)) {
-                               ret = false;
-                               page_vma_mapped_walk_done(&pvmw);
-                               break;
-                       }
-               }
-
                /* Nuke the page table entry. */
                flush_cache_page(vma, address, pte_pfn(*pvmw.pte));
                if (should_defer_flush(mm, flags)) {