[PATCH] remove set_page_count() outside mm/

set_page_count usage outside mm/ is limited to setting the refcount to 1.
Remove set_page_count from outside mm/, and replace those users with
init_page_count() and set_page_refcounted().

This allows more debug checking, and tighter control on how code is allowed
to play around with page->_count.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 8 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e197818a7cf6..7f65b5a63bb3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -442,7 +442,7 @@ void fastcall __init __free_pages_bootmem(struct page *page, unsigned int order)
         if (order == 0) {
                 __ClearPageReserved(page);
                 set_page_count(page, 0);
-                set_page_refs(page, 0);
+                set_page_refcounted(page);
                 __free_page(page);
         } else {
                 int loop;
@@ -457,7 +457,7 @@ void fastcall __init __free_pages_bootmem(struct page *page, unsigned int order)
                         set_page_count(p, 0);
                 }
 
-                set_page_refs(page, order);
+                set_page_refcounted(page);
                 __free_pages(page, order);
         }
 }
@@ -525,7 +525,7 @@ static int prep_new_page(struct page *page, int order)
                         1 << PG_referenced | 1 << PG_arch_1 |
                         1 << PG_checked | 1 << PG_mappedtodisk);
         set_page_private(page, 0);
-        set_page_refs(page, order);
+        set_page_refcounted(page);
         kernel_map_pages(page, 1 << order, 1);
         return 0;
 }
@@ -755,10 +755,8 @@ void split_page(struct page *page, unsigned int order)
 
         BUG_ON(PageCompound(page));
         BUG_ON(!page_count(page));
-        for (i = 1; i < (1 << order); i++) {
-                BUG_ON(page_count(page + i));
-                set_page_count(page + i, 1);
-        }
+        for (i = 1; i < (1 << order); i++)
+                set_page_refcounted(page + i);
 }
 
 /*
@@ -1771,7 +1769,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
                         continue;
                 page = pfn_to_page(pfn);
                 set_page_links(page, zone, nid, pfn);
-                set_page_count(page, 1);
+                init_page_count(page);
                 reset_page_mapcount(page);
                 SetPageReserved(page);
                 INIT_LIST_HEAD(&page->lru);