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@xxxxxxxxxxxxxxx>
---
include/linux/page-flags.h | 41 +++++++++++++++++++++--------------------
1 file changed, 21 insertions(+), 20 deletions(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 815246a80e2d..713d3f2c2468 100644
--- 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)
{
--
2.5.1
--
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