From: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date: Wed, 11 Feb 2015 23:24:46 +0000 (-0800)
Subject: mm: add fields for compound destructor and order into struct page
X-Git-Tag: fixes-v4.0-rc1~131^2~82
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e4b294c2d8f73af4cd41ff30638ad0e4769dc56a;p=pandora-kernel.git

mm: add fields for compound destructor and order into struct page

Currently, we use lru.next/lru.prev plus cast to access or set
destructor and order of compound page.

Let's replace it with explicit fields in struct page.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 65db4aee738a..8dd4fde9d2e5 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -627,29 +627,28 @@ int split_free_page(struct page *page);
  * prototype for that function and accessor functions.
  * These are _only_ valid on the head of a PG_compound page.
  */
-typedef void compound_page_dtor(struct page *);
 
 static inline void set_compound_page_dtor(struct page *page,
 						compound_page_dtor *dtor)
 {
-	page[1].lru.next = (void *)dtor;
+	page[1].compound_dtor = dtor;
 }
 
 static inline compound_page_dtor *get_compound_page_dtor(struct page *page)
 {
-	return (compound_page_dtor *)page[1].lru.next;
+	return page[1].compound_dtor;
 }
 
 static inline int compound_order(struct page *page)
 {
 	if (!PageHead(page))
 		return 0;
-	return (unsigned long)page[1].lru.prev;
+	return page[1].compound_order;
 }
 
 static inline void set_compound_order(struct page *page, unsigned long order)
 {
-	page[1].lru.prev = (void *)order;
+	page[1].compound_order = order;
 }
 
 #ifdef CONFIG_MMU
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