mm: uninline page_mapped()

It's huge.  Uninlining it saves 206 bytes per callsite.  Shaves 4924 bytes
from the x86_64 allmodconfig vmlinux.

Cc: Steve Capper <steve.capper@arm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/mm.h

@@ -1019,26 +1019,7 @@ static inline pgoff_t page_file_index(struct page *page)
 	return page->index;
 }
 
-/*
- * Return true if this page is mapped into pagetables.
- * For compound page it returns true if any subpage of compound page is mapped.
- */
-static inline bool page_mapped(struct page *page)
-{
-	int i;
-	if (likely(!PageCompound(page)))
-		return atomic_read(&page->_mapcount) >= 0;
-	page = compound_head(page);
-	if (atomic_read(compound_mapcount_ptr(page)) >= 0)
-		return true;
-	if (PageHuge(page))
-		return false;
-	for (i = 0; i < hpage_nr_pages(page); i++) {
-		if (atomic_read(&page[i]._mapcount) >= 0)
-			return true;
-	}
-	return false;
-}
+bool page_mapped(struct page *page);
 
 /*
  * Return true only if the page has been allocated with

mm/util.c

@@ -346,6 +346,28 @@ void *page_rmapping(struct page *page)
 	return __page_rmapping(page);
 }
 
+/*
+ * Return true if this page is mapped into pagetables.
+ * For compound page it returns true if any subpage of compound page is mapped.
+ */
+bool page_mapped(struct page *page)
+{
+	int i;
+	if (likely(!PageCompound(page)))
+		return atomic_read(&page->_mapcount) >= 0;
+	page = compound_head(page);
+	if (atomic_read(compound_mapcount_ptr(page)) >= 0)
+		return true;
+	if (PageHuge(page))
+		return false;
+	for (i = 0; i < hpage_nr_pages(page); i++) {
+		if (atomic_read(&page[i]._mapcount) >= 0)
+			return true;
+	}
+	return false;
+}
+EXPORT_SYMBOL(page_mapped);
+
 struct anon_vma *page_anon_vma(struct page *page)
 {
 	unsigned long mapping;