mm: fix page_freeze_refs and page_unfreeze_refs in comments

page_freeze_refs/page_unfreeze_refs have already been relplaced by
page_ref_freeze/page_ref_unfreeze , but they are not modified in the
comments.

Link: http://lkml.kernel.org/r/1532590226-106038-1-git-send-email-jiang.biao2@zte.com.cn
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/ksm.c

@@ -703,7 +703,7 @@ again:
 	 * We cannot do anything with the page while its refcount is 0.
 	 * Usually 0 means free, or tail of a higher-order page: in which
 	 * case this node is no longer referenced, and should be freed;
-	 * however, it might mean that the page is under page_freeze_refs().
+	 * however, it might mean that the page is under page_ref_freeze().
 	 * The __remove_mapping() case is easy, again the node is now stale;
 	 * but if page is swapcache in migrate_page_move_mapping(), it might
 	 * still be our page, in which case it's essential to keep the node.
@@ -714,7 +714,7 @@ again:
 		 * work here too.  We have chosen the !PageSwapCache test to
 		 * optimize the common case, when the page is or is about to
 		 * be freed: PageSwapCache is cleared (under spin_lock_irq)
-		 * in the freeze_refs section of __remove_mapping(); but Anon
+		 * in the ref_freeze section of __remove_mapping(); but Anon
 		 * page->mapping reset to NULL later, in free_pages_prepare().
 		 */
 		if (!PageSwapCache(page))

mm/memory-failure.c

@@ -1167,7 +1167,7 @@ int memory_failure(unsigned long pfn, int flags)
 	 *    R/W the page; let's pray that the page has been
 	 *    used and will be freed some time later.
 	 * In fact it's dangerous to directly bump up page count from 0,
-	 * that may make page_freeze_refs()/page_unfreeze_refs() mismatch.
+	 * that may make page_ref_freeze()/page_ref_unfreeze() mismatch.
 	 */
 	if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) {
 		if (is_free_buddy_page(p)) {

mm/vmscan.c

@@ -903,7 +903,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
 		refcount = 2;
 	if (!page_ref_freeze(page, refcount))
 		goto cannot_free;
-	/* note: atomic_cmpxchg in page_freeze_refs provides the smp_rmb */
+	/* note: atomic_cmpxchg in page_ref_freeze provides the smp_rmb */
 	if (unlikely(PageDirty(page))) {
 		page_ref_unfreeze(page, refcount);
 		goto cannot_free;