[RFC][PATCH] overwride page->mapping [1/3] cleanup

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

Clean up: Gather all page->mapping handling functions to page-cache.h

no functional changes. (will be merged to "add page->mapping interface function"
patch.)

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

---
 include/linux/mm.h         |   47 --------------------------------------------
 include/linux/page-cache.h |   48 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 47 deletions(-)

Index: test-2.6.23-rc4-mm1/include/linux/mm.h
===================================================================
--- test-2.6.23-rc4-mm1.orig/include/linux/mm.h
+++ test-2.6.23-rc4-mm1/include/linux/mm.h
@@ -550,53 +550,6 @@ void page_address_init(void);
 #endif
 
 /*
- * On an anonymous page mapped into a user virtual memory area,
- * page->mapping points to its anon_vma, not to a struct address_space;
- * with the PAGE_MAPPING_ANON bit set to distinguish it.
- *
- * Please note that, confusingly, "page_mapping" refers to the inode
- * address_space which maps the page from disk; whereas "page_mapped"
- * refers to user virtual address space into which the page is mapped.
- */
-#define PAGE_MAPPING_ANON	1
-
-extern struct address_space swapper_space;
-static inline struct address_space *page_mapping(struct page *page)
-{
-	struct address_space *mapping = (struct address_space *)page->mapping;
-
-	VM_BUG_ON(PageSlab(page));
-	if (unlikely(PageSwapCache(page)))
-		mapping = &swapper_space;
-#ifdef CONFIG_SLUB
-	else if (unlikely(PageSlab(page)))
-		mapping = NULL;
-#endif
-	else if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))
-		mapping = NULL;
-	return mapping;
-}
-
-static inline int PageAnon(struct page *page)
-{
-	return (page->mapping & PAGE_MAPPING_ANON) != 0;
-}
-
-static inline struct anon_vma *page_mapping_anon(struct page *page)
-{
-	if (PageAnon(page))
-		return (struct anon_vma *)(page->mapping - PAGE_MAPPING_ANON);
-	return NULL;
-}
-
-static inline struct address_space *page_mapping_cache(struct page *page)
-{
-	if (PageAnon(page))
-		return NULL;
-	return (struct address_space *) page->mapping;
-}
-
-/*
  * Return the pagecache index of the passed page.  Regular pagecache pages
  * use ->index whereas swapcache pages use ->private
  */
Index: test-2.6.23-rc4-mm1/include/linux/page-cache.h
===================================================================
--- test-2.6.23-rc4-mm1.orig/include/linux/page-cache.h
+++ test-2.6.23-rc4-mm1/include/linux/page-cache.h
@@ -7,8 +7,56 @@
 #define _LINUX_PAGECACHE_H
 
 #include <linux/mm.h>
+#include <linux/rmap.h>
 /* page_mapping_xxx() function is defined in mm.h */
 
+/*
+ * On an anonymous page mapped into a user virtual memory area,
+ * page->mapping points to its anon_vma, not to a struct address_space;
+ * with the PAGE_MAPPING_ANON bit set to distinguish it.
+ *
+ * Please note that, confusingly, "page_mapping" refers to the inode
+ * address_space which maps the page from disk; whereas "page_mapped"
+ * refers to user virtual address space into which the page is mapped.
+ */
+#define PAGE_MAPPING_ANON	1
+
+static inline int PageAnon(struct page *page)
+{
+	return (page->mapping & PAGE_MAPPING_ANON) != 0;
+}
+
+extern struct address_space swapper_space;
+static inline struct address_space *page_mapping(struct page *page)
+{
+	struct address_space *mapping = (struct address_space *)page->mapping;
+
+	VM_BUG_ON(PageSlab(page));
+	if (unlikely(PageSwapCache(page)))
+		mapping = &swapper_space;
+#ifdef CONFIG_SLUB
+	else if (unlikely(PageSlab(page)))
+		mapping = NULL;
+#endif
+	else if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))
+		mapping = NULL;
+	return mapping;
+}
+
+static inline struct anon_vma *page_mapping_anon(struct page *page)
+{
+	if (!page->mapping || !PageAnon(page))
+		return NULL;
+	return (struct anon_vma *)(page->mapping - PAGE_MAPPING_ANON);
+}
+
+static inline struct address_space *page_mapping_cache(struct page *page)
+{
+	if (!page->mapping || PageAnon(page))
+		return NULL;
+	return (struct address_space *)page->mapping;
+}
+
 static inline int page_is_pagecache(struct page *page)
 {
 	if (!page->mapping || (page->mapping & PAGE_MAPPING_ANON))

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