---
 include/linux/mm.h |   61 +++++++++++++++++++++++++++++++++--------------------
 mm/vmalloc.c       |    9 +++++++
 2 files changed, 48 insertions(+), 22 deletions(-)

Index: linux-2.6/include/linux/mm.h
===================================================================
--- linux-2.6.orig/include/linux/mm.h	2007-09-20 19:07:19.000000000 -0700
+++ linux-2.6/include/linux/mm.h	2007-09-20 19:08:28.000000000 -0700
@@ -294,6 +294,10 @@ static inline int get_page_unless_zero(s
 	return atomic_inc_not_zero(&page->_count);
 }
 
+/*
+ * compound_head() works on virtual compound pages since
+ * they also have the first_page pointer.
+ */
 static inline struct page *compound_head(struct page *page)
 {
 	if (unlikely(PageTail(page)))
@@ -313,12 +317,6 @@ static inline void get_page(struct page 
 	atomic_inc(&page->_count);
 }
 
-static inline struct page *virt_to_head_page(const void *x)
-{
-	struct page *page = virt_to_page(x);
-	return compound_head(page);
-}
-
 /*
  * Setup the page count before being freed into the page allocator for
  * the first time (boot or memory hotplug)
@@ -334,33 +332,50 @@ void put_pages_list(struct list_head *pa
 void split_page(struct page *page, unsigned int order);
 
 /*
- * Compound pages have a destructor function.  Provide a
- * prototype for that function and accessor functions.
+ * Compound pages have a destructor function (but not virtual compounds!).
+ * Provide a prototype for that function and accessor functions.
  * These are _only_ valid on the head of a PG_compound page.
+ *
+ * And these functions referencing page[1] will not work on a virtual
+ * compound page since the second page may not follow the first one
+ * directly.
  */
 typedef void compound_page_dtor(struct page *);
 
+struct page *vmalloc_to_page(const void *);
+void *vmalloc_address(struct page *);
+
+static inline struct page *compound_part(struct page *page, int n)
+{
+	extern struct page *vmalloc_part(struct page *page, int n);
+
+	if (likely(!PageVcompound(page)))
+		return page + n;
+	return vmalloc_part(page, n);
+}
+
 static inline void set_compound_page_dtor(struct page *page,
 						compound_page_dtor *dtor)
 {
-	page[1].lru.next = (void *)dtor;
+	compound_part(page, 1)->lru.next = (void *)dtor;
 }
 
 static inline compound_page_dtor *get_compound_page_dtor(struct page *page)
 {
-	return (compound_page_dtor *)page[1].lru.next;
+	return (compound_page_dtor *)compound_part(page, 1)->lru.next;
 }
 
-static inline int compound_order(struct page *page)
+static inline void set_compound_order(struct page *page, unsigned long order)
 {
-	if (!PageHead(page))
-		return 0;
-	return (unsigned long)page[1].lru.prev;
+	compound_part(page, 1)->lru.prev = (void *)order;
 }
 
-static inline void set_compound_order(struct page *page, unsigned long order)
+/* This is working on a compound page */
+static inline int compound_order(struct page *page)
 {
-	page[1].lru.prev = (void *)order;
+	if (likely(!PageHead(page)))
+		return 0;
+	return (unsigned long)compound_part(page, 1)->lru.prev;
 }
 
 /*
@@ -1166,24 +1181,26 @@ static inline int is_vmalloc_addr(const 
 	return addr >= VMALLOC_START && addr < VMALLOC_END;
 }
 
-static inline void *to_address(struct page *page)
+static inline void *page_to_addr(struct page *page)
 {
-	extern void *vmalloc_address(struct page *);
-
 	if (unlikely(PageVcompound(page)))
 		return vmalloc_address(page);
 	return page_address(page);
 }
 
-static inline struct page *to_page(void *x)
+static inline struct page *addr_to_page(const void *x)
 {
-	extern struct page *vmalloc_to_page(const void *);
-
 	if (unlikely(is_vmalloc_addr(x)))
 		return vmalloc_to_page(x);
 	return virt_to_page(x);
 }
 
+static inline struct page *virt_to_head_page(const void *x)
+{
+	struct page *page = addr_to_page(x);
+	return compound_head(page);
+}
+
 pgprot_t vm_get_page_prot(unsigned long vm_flags);
 struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr);
 int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
Index: linux-2.6/mm/vmalloc.c
===================================================================
--- linux-2.6.orig/mm/vmalloc.c	2007-09-20 19:07:19.000000000 -0700
+++ linux-2.6/mm/vmalloc.c	2007-09-20 19:08:28.000000000 -0700
@@ -656,6 +656,15 @@ void *vmalloc(unsigned long size)
 }
 EXPORT_SYMBOL(vmalloc);
 
+/*
+ * Given a pointer to the first page struct:
+ * Determine a pointer to the nth page.
+ */
+struct page *vmalloc_part(struct page *page, int n)
+{
+	return vmalloc_to_page(vmalloc_address(page) + n * PAGE_SIZE);
+}
+
 /**
  * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
  * @size: allocation size