page-flags: move code around

The preparation patch: we are going to use compound_head(), PageTail()
and PageCompound() to define page-flags helpers.

Let's define them before macros.

We cannot user PageHead() helper in PageCompound() as it's not yet
defined -- use test_bit(PG_head, &page->flags) instead.

Signed-off-by: Kirill A. Shutemov <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Steve Capper <[email protected]>
Cc: "Aneesh Kumar K.V" <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Jerome Marchand <[email protected]>
Cc: Jérôme Glisse <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 45792d01edea47f3f44bd464a4fd1f72503152a7..83161a22509ca5bc7d7fb27a7962c2373bf754c4 100644 (file)
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -133,6 +133,27 @@ enum pageflags {
 
 #ifndef __GENERATING_BOUNDS_H
 
+struct page;   /* forward declaration */
+
+static inline struct page *compound_head(struct page *page)
+{
+       unsigned long head = READ_ONCE(page->compound_head);
+
+       if (unlikely(head & 1))
+               return (struct page *) (head - 1);
+       return page;
+}
+
+static inline int PageTail(struct page *page)
+{
+       return READ_ONCE(page->compound_head) & 1;
+}
+
+static inline int PageCompound(struct page *page)
+{
+       return test_bit(PG_head, &page->flags) || PageTail(page);
+}
+
 /*
  * Macros to create function definitions for page flags
  */
@@ -204,7 +225,6 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; }
 #define TESTSCFLAG_FALSE(uname)                                                \
        TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
 
-struct page;   /* forward declaration */
 
 TESTPAGEFLAG(Locked, locked)
 PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error)
@@ -395,11 +415,6 @@ static inline void set_page_writeback_keepwrite(struct page *page)
 
 __PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head)
 
-static inline int PageTail(struct page *page)
-{
-       return READ_ONCE(page->compound_head) & 1;
-}
-
 static inline void set_compound_head(struct page *page, struct page *head)
 {
        WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
@@ -410,20 +425,6 @@ static inline void clear_compound_head(struct page *page)
        WRITE_ONCE(page->compound_head, 0);
 }
 
-static inline struct page *compound_head(struct page *page)
-{
-       unsigned long head = READ_ONCE(page->compound_head);
-
-       if (unlikely(head & 1))
-               return (struct page *) (head - 1);
-       return page;
-}
-
-static inline int PageCompound(struct page *page)
-{
-       return PageHead(page) || PageTail(page);
-
-}
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 static inline void ClearPageCompound(struct page *page)
 {