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 <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 45792d0..83161a2 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)
 {