mm: return boolean from page_is_file_cache()

page_is_file_cache() has been used for both boolean checks and LRU
arithmetic, which was always a bit weird.

Now that page_lru_base_type() exists for LRU arithmetic, make
page_is_file_cache() a real predicate function and adjust the
boolean-using callsites to drop those pesky double negations.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 6 deletions

diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 99977ff45b8..8835b877b8d 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -5,7 +5,7 @@
  * page_is_file_cache - should the page be on a file LRU or anon LRU?
  * @page: the page to test
  *
- * Returns LRU_FILE if @page is page cache page backed by a regular filesystem,
+ * Returns 1 if @page is page cache page backed by a regular filesystem,
  * or 0 if @page is anonymous, tmpfs or otherwise ram or swap backed.
  * Used by functions that manipulate the LRU lists, to sort a page
  * onto the right LRU list.
@@ -16,11 +16,7 @@
  */
 static inline int page_is_file_cache(struct page *page)
 {
-        if (PageSwapBacked(page))
-                return 0;
-
-        /* The page is page cache backed by a normal filesystem. */
-        return LRU_FILE;
+        return !PageSwapBacked(page);
 }
 
 static inline void