2 files changed, 44 insertions, 5 deletions

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 0b73c536afd2..9e51f77d44ca 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -44,6 +44,7 @@ int hugetlb_reserve_pages(struct inode *inode, long from, long to,
                                                 int acctflags);
 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed);
 void __isolate_hwpoisoned_huge_page(struct page *page);
+void copy_huge_page(struct page *dst, struct page *src);
 
 extern unsigned long hugepages_treat_as_movable;
 extern const unsigned long hugetlb_zero, hugetlb_infinity;
@@ -102,6 +103,9 @@ static inline void hugetlb_report_meminfo(struct seq_file *m)
 #define hugetlb_fault(mm, vma, addr, flags)     ({ BUG(); 0; })
 #define huge_pte_offset(mm, address)    0
 #define __isolate_hwpoisoned_huge_page(page)    0
+static inline void copy_huge_page(struct page *dst, struct page *src)
+{
+}
 
 #define hugetlb_change_protection(vma, address, end, newprot)
 
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 83fa0c3b6e2b..a73dbdcb89eb 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -423,14 +423,14 @@ static void clear_huge_page(struct page *page,
         }
 }
 
-static void copy_gigantic_page(struct page *dst, struct page *src,
+static void copy_user_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);
@@ -440,14 +440,15 @@ static void copy_gigantic_page(struct page *dst, struct page *src,
                 src = mem_map_next(src, src_base, i);
         }
 }
-static void copy_huge_page(struct page *dst, struct page *src,
+
+static void copy_user_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)) {
-                copy_gigantic_page(dst, src, addr, vma);
+                copy_user_gigantic_page(dst, src, addr, vma);
                 return;
         }
 
@@ -458,6 +459,40 @@ static void copy_huge_page(struct page *dst, struct page *src,
         }
 }
 
+static void copy_gigantic_page(struct page *dst, struct page *src)
+{
+        int i;
+        struct hstate *h = page_hstate(src);
+        struct page *dst_base = dst;
+        struct page *src_base = src;
+
+        for (i = 0; i < pages_per_huge_page(h); ) {
+                cond_resched();
+                copy_highpage(dst, src);
+
+                i++;
+                dst = mem_map_next(dst, dst_base, i);
+                src = mem_map_next(src, src_base, i);
+        }
+}
+
+void copy_huge_page(struct page *dst, struct page *src)
+{
+        int i;
+        struct hstate *h = page_hstate(src);
+
+        if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
+                copy_gigantic_page(dst, src);
+                return;
+        }
+
+        might_sleep();
+        for (i = 0; i < pages_per_huge_page(h); i++) {
+                cond_resched();
+                copy_highpage(dst + i, src + i);
+        }
+}
+
 static void enqueue_huge_page(struct hstate *h, struct page *page)
 {
         int nid = page_to_nid(page);
@@ -2412,7 +2447,7 @@ retry_avoidcopy:
         if (unlikely(anon_vma_prepare(vma)))
                 return VM_FAULT_OOM;
 
-        copy_huge_page(new_page, old_page, address, vma);
+        copy_user_huge_page(new_page, old_page, address, vma);
         __SetPageUptodate(new_page);
 
         /*