1 files changed, 36 insertions, 1 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 421aee99b84a..e6afe527bd09 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -354,11 +354,26 @@ static int vma_has_reserves(struct vm_area_struct *vma)
         return 0;
 }
 
+static void clear_gigantic_page(struct page *page,
+                        unsigned long addr, unsigned long sz)
+{
+        int i;
+        struct page *p = page;
+
+        might_sleep();
+        for (i = 0; i < sz/PAGE_SIZE; i++, p = mem_map_next(p, page, i)) {
+                cond_resched();
+                clear_user_highpage(p, addr + i * PAGE_SIZE);
+        }
+}
 static void clear_huge_page(struct page *page,
                         unsigned long addr, unsigned long sz)
 {
         int i;
 
+        if (unlikely(sz > MAX_ORDER_NR_PAGES))
+                return clear_gigantic_page(page, addr, sz);
+
         might_sleep();
         for (i = 0; i < sz/PAGE_SIZE; i++) {
                 cond_resched();
@@ -366,12 +381,32 @@ static void clear_huge_page(struct page *page,
         }
 }
 
+static void copy_gigantic_page(struct page *dst, struct page *src,
+                           unsigned long addr, struct vm_area_struct *vma)
+{
+        int i;
+        struct hstate *h = hstate_vma(vma);
+        struct page *dst_base = dst;
+        struct page *src_base = src;
+        might_sleep();
+        for (i = 0; i < pages_per_huge_page(h); ) {
+                cond_resched();
+                copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
+
+                i++;
+                dst = mem_map_next(dst, dst_base, i);
+                src = mem_map_next(src, src_base, i);
+        }
+}
 static void copy_huge_page(struct page *dst, struct page *src,
                            unsigned long addr, struct vm_area_struct *vma)
 {
         int i;
         struct hstate *h = hstate_vma(vma);
 
+        if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES))
+                return copy_gigantic_page(dst, src, addr, vma);
+
         might_sleep();
         for (i = 0; i < pages_per_huge_page(h); i++) {
                 cond_resched();
@@ -2130,7 +2165,7 @@ same_page:
                         if (zeropage_ok)
                                 pages[i] = ZERO_PAGE(0);
                         else
-                                pages[i] = page + pfn_offset;
+                                pages[i] = mem_map_offset(page, pfn_offset);
                         get_page(pages[i]);
                 }