futex: Take hugepages into account when generating futex_key

[linux-2.6-block.git] / mm / hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index f8feeeca6686543713a1dada46759b60b2eae240..aea87ced4268edde3973c0f47394c345c8f997ab 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -690,6 +690,23 @@ int PageHuge(struct page *page)
 }
 EXPORT_SYMBOL_GPL(PageHuge);
 
+pgoff_t __basepage_index(struct page *page)
+{
+       struct page *page_head = compound_head(page);
+       pgoff_t index = page_index(page_head);
+       unsigned long compound_idx;
+
+       if (!PageHuge(page_head))
+               return page_index(page);
+
+       if (compound_order(page_head) >= MAX_ORDER)
+               compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
+       else
+               compound_idx = page - page_head;
+
+       return (index << compound_order(page_head)) + compound_idx;
+}
+
 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
 {
        struct page *page;