1 files changed, 29 insertions, 0 deletions

diff --git a/mm/internal.h b/mm/internal.h
index e4e728bdf324..13333bc2eb68 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -17,6 +17,7 @@ void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
                 unsigned long floor, unsigned long ceiling);
 
 extern void prep_compound_page(struct page *page, unsigned long order);
+extern void prep_compound_gigantic_page(struct page *page, unsigned long order);
 
 static inline void set_page_count(struct page *page, int v)
 {
@@ -176,6 +177,34 @@ 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
  * in those cases. SPARSEMEM, however, allows for memory hotplug,