thp: clear_copy_huge_page

Move the copy/clear_huge_page functions to common code to share between
hugetlb.c and huge_memory.c.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 71 insertions, 0 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 567bca80ea53..60e1c68d8218 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3645,3 +3645,74 @@ void might_fault(void)
 }
 EXPORT_SYMBOL(might_fault);
 #endif
+
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
+static void clear_gigantic_page(struct page *page,
+                                unsigned long addr,
+                                unsigned int pages_per_huge_page)
+{
+        int i;
+        struct page *p = page;
+
+        might_sleep();
+        for (i = 0; i < pages_per_huge_page;
+             i++, p = mem_map_next(p, page, i)) {
+                cond_resched();
+                clear_user_highpage(p, addr + i * PAGE_SIZE);
+        }
+}
+void clear_huge_page(struct page *page,
+                     unsigned long addr, unsigned int pages_per_huge_page)
+{
+        int i;
+
+        if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
+                clear_gigantic_page(page, addr, pages_per_huge_page);
+                return;
+        }
+
+        might_sleep();
+        for (i = 0; i < pages_per_huge_page; i++) {
+                cond_resched();
+                clear_user_highpage(page + i, addr + i * PAGE_SIZE);
+        }
+}
+
+static void copy_user_gigantic_page(struct page *dst, struct page *src,
+                                    unsigned long addr,
+                                    struct vm_area_struct *vma,
+                                    unsigned int pages_per_huge_page)
+{
+        int i;
+        struct page *dst_base = dst;
+        struct page *src_base = src;
+
+        for (i = 0; i < pages_per_huge_page; ) {
+                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);
+        }
+}
+
+void copy_user_huge_page(struct page *dst, struct page *src,
+                         unsigned long addr, struct vm_area_struct *vma,
+                         unsigned int pages_per_huge_page)
+{
+        int i;
+
+        if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
+                copy_user_gigantic_page(dst, src, addr, vma,
+                                        pages_per_huge_page);
+                return;
+        }
+
+        might_sleep();
+        for (i = 0; i < pages_per_huge_page; i++) {
+                cond_resched();
+                copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
+        }
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */