Export prep_compound_page to the hugetlb allocator

hugetlb will need to get compound pages from bootmem to handle
the case of them being larger than MAX_ORDER. Export
the constructor function needed for this.

Signed-off-by: Andi Kleen <ak@suse.de>

---
 mm/internal.h   |    2 ++
 mm/page_alloc.c |    2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

Index: linux/mm/internal.h
===================================================================
--- linux.orig/mm/internal.h
+++ linux/mm/internal.h
@@ -13,6 +13,8 @@
 
 #include <linux/mm.h>
 
+extern void prep_compound_page(struct page *page, unsigned long order);
+
 static inline void set_page_count(struct page *page, int v)
 {
 	atomic_set(&page->_count, v);
Index: linux/mm/page_alloc.c
===================================================================
--- linux.orig/mm/page_alloc.c
+++ linux/mm/page_alloc.c
@@ -272,7 +272,7 @@ static void free_compound_page(struct pa
 	__free_pages_ok(page, compound_order(page));
 }
 
-static void prep_compound_page(struct page *page, unsigned long order)
+void prep_compound_page(struct page *page, unsigned long order)
 {
 	int i;
 	int nr_pages = 1 << order;