mm: page_counter: let page_counter_try_charge() return bool

page_counter_try_charge() currently returns 0 on success and -ENOMEM on
failure, which is surprising behavior given the function name.

Make it follow the expected pattern of try_stuff() functions that return a
boolean true to indicate success, or false for failure.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_counter.c b/mm/page_counter.c
index 11b4bed..7c6a63d 100644
--- a/mm/page_counter.c
+++ b/mm/page_counter.c
@@ -56,12 +56,12 @@
  * @nr_pages: number of pages to charge
  * @fail: points first counter to hit its limit, if any
  *
- * Returns 0 on success, or -ENOMEM and @fail if the counter or one of
- * its ancestors has hit its configured limit.
+ * Returns %true on success, or %false and @fail if the counter or one
+ * of its ancestors has hit its configured limit.
  */
-int page_counter_try_charge(struct page_counter *counter,
-			    unsigned long nr_pages,
-			    struct page_counter **fail)
+bool page_counter_try_charge(struct page_counter *counter,
+			     unsigned long nr_pages,
+			     struct page_counter **fail)
 {
 	struct page_counter *c;
 
@@ -99,13 +99,13 @@
 		if (new > c->watermark)
 			c->watermark = new;
 	}
-	return 0;
+	return true;
 
 failed:
 	for (c = counter; c != *fail; c = c->parent)
 		page_counter_cancel(c, nr_pages);
 
-	return -ENOMEM;
+	return false;
 }
 
 /**