hugetlbfs: handle pages higher order than MAX_ORDER

[linux-2.6-omap-h63xx.git] / mm / internal.h

diff --git a/mm/internal.h b/mm/internal.h
index e4e728bdf324fc62a24ba0c951869989ab081ea1..f482460de3e69b1f25c2e6fb97d15c1553516005 100644 (file)
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -175,6 +175,34 @@ static inline void free_page_mlock(struct page *page) { }
 
 #endif /* CONFIG_UNEVICTABLE_LRU */
 
+/*
+ * Return the mem_map entry representing the 'offset' subpage within
+ * the maximally aligned gigantic page 'base'.  Handle any discontiguity
+ * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
+ */
+static inline struct page *mem_map_offset(struct page *base, int offset)
+{
+       if (unlikely(offset >= MAX_ORDER_NR_PAGES))
+               return pfn_to_page(page_to_pfn(base) + offset);
+       return base + offset;
+}
+
+/*
+ * Iterator over all subpages withing the maximally aligned gigantic
+ * page 'base'.  Handle any discontiguity in the mem_map.
+ */
+static inline struct page *mem_map_next(struct page *iter,
+                                               struct page *base, int offset)
+{
+       if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
+               unsigned long pfn = page_to_pfn(base) + offset;
+               if (!pfn_valid(pfn))
+                       return NULL;
+               return pfn_to_page(pfn);
+       }
+       return iter + 1;
+}
+
 /*
  * FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
  * so all functions starting at paging_init should be marked __init