mm: remove rest of ACCESS_ONCE() usages

We converted some of the usages of ACCESS_ONCE to READ_ONCE in the mm/
tree since it doesn't work reliably on non-scalar types.

This patch removes the rest of the usages of ACCESS_ONCE, and use the new
READ_ONCE API for the read accesses.  This makes things cleaner, instead
of using separate/multiple sets of APIs.

Signed-off-by: Jason Low <jason.low2@hp.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index c161a14b6a8f..24dd3f9fee27 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -456,7 +456,7 @@ struct anon_vma *page_get_anon_vma(struct page *page)
         unsigned long anon_mapping;
 
         rcu_read_lock();
-        anon_mapping = (unsigned long) ACCESS_ONCE(page->mapping);
+        anon_mapping = (unsigned long)READ_ONCE(page->mapping);
         if ((anon_mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
                 goto out;
         if (!page_mapped(page))
@@ -500,14 +500,14 @@ struct anon_vma *page_lock_anon_vma_read(struct page *page)
         unsigned long anon_mapping;
 
         rcu_read_lock();
-        anon_mapping = (unsigned long) ACCESS_ONCE(page->mapping);
+        anon_mapping = (unsigned long)READ_ONCE(page->mapping);
         if ((anon_mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
                 goto out;
         if (!page_mapped(page))
                 goto out;
 
         anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON);
-        root_anon_vma = ACCESS_ONCE(anon_vma->root);
+        root_anon_vma = READ_ONCE(anon_vma->root);
         if (down_read_trylock(&root_anon_vma->rwsem)) {
                 /*
                  * If the page is still mapped, then this anon_vma is still