mm: CONFIG_MMU for PG_mlocked

Remove three degrees of obfuscation, left over from when we had
CONFIG_UNEVICTABLE_LRU.  MLOCK_PAGES is CONFIG_HAVE_MLOCKED_PAGE_BIT is
CONFIG_HAVE_MLOCK is CONFIG_MMU.  rmap.o (and memory-failure.o) are only
built when CONFIG_MMU, so don't need such conditions at all.

Somehow, I feel no compulsion to remove the CONFIG_HAVE_MLOCK* lines from
169 defconfigs: leave those to evolve in due course.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/internal.h b/mm/internal.h
index 22ec8d2..cb7d92d 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -63,17 +63,6 @@
 	return page_private(page);
 }
 
-#ifdef CONFIG_HAVE_MLOCK
-extern long mlock_vma_pages_range(struct vm_area_struct *vma,
-			unsigned long start, unsigned long end);
-extern void munlock_vma_pages_range(struct vm_area_struct *vma,
-			unsigned long start, unsigned long end);
-static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
-{
-	munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
-}
-#endif
-
 /*
  * unevictable_migrate_page() called only from migrate_page_copy() to
  * migrate unevictable flag to new page.
@@ -86,7 +75,16 @@
 		SetPageUnevictable(new);
 }
 
-#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
+#ifdef CONFIG_MMU
+extern long mlock_vma_pages_range(struct vm_area_struct *vma,
+			unsigned long start, unsigned long end);
+extern void munlock_vma_pages_range(struct vm_area_struct *vma,
+			unsigned long start, unsigned long end);
+static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
+{
+	munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
+}
+
 /*
  * Called only in fault path via page_evictable() for a new page
  * to determine if it's being mapped into a LOCKED vma.
@@ -144,7 +142,7 @@
 	}
 }
 
-#else /* CONFIG_HAVE_MLOCKED_PAGE_BIT */
+#else /* !CONFIG_MMU */
 static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p)
 {
 	return 0;
@@ -153,7 +151,7 @@
 static inline void mlock_vma_page(struct page *page) { }
 static inline void mlock_migrate_page(struct page *new, struct page *old) { }
 
-#endif /* CONFIG_HAVE_MLOCKED_PAGE_BIT */
+#endif /* !CONFIG_MMU */
 
 /*
  * Return the mem_map entry representing the 'offset' subpage within