---
 include/linux/mm.h |    1 +
 mm/memory.c        |   13 +++++++++++++
 2 files changed, 14 insertions(+)

Index: linux-2.6/include/linux/mm.h
===================================================================
--- linux-2.6.orig/include/linux/mm.h	2008-02-14 18:59:12.000000000 -0800
+++ linux-2.6/include/linux/mm.h	2008-02-14 18:59:31.000000000 -0800
@@ -1147,6 +1147,7 @@ struct page *follow_page(struct vm_area_
 #define FOLL_TOUCH	0x02	/* mark page accessed */
 #define FOLL_GET	0x04	/* do get_page on page */
 #define FOLL_ANON	0x08	/* give ZERO_PAGE if no pgtable */
+#define FOLL_LOCK	0x08	/* attempt to lock the page */
 
 typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
 			void *data);
Index: linux-2.6/mm/memory.c
===================================================================
--- linux-2.6.orig/mm/memory.c	2008-02-14 18:59:12.000000000 -0800
+++ linux-2.6/mm/memory.c	2008-02-14 19:10:00.000000000 -0800
@@ -975,6 +975,15 @@ struct page *follow_page(struct vm_area_
 			set_page_dirty(page);
 		mark_page_accessed(page);
 	}
+
+	if (flags & FOLL_LOCK) {
+		if (TestSetPageLocked(page)) {
+			if (flags & FOLL_GET)
+				put_page(page);
+			page = NULL;
+		}
+	}
+
 unlock:
 	pte_unmap_unlock(ptep, ptl);
 out:
@@ -1068,6 +1077,10 @@ int get_user_pages(struct task_struct *t
 		foll_flags = FOLL_TOUCH;
 		if (pages)
 			foll_flags |= FOLL_GET;
+
+		if (lock)
+			foll_flags |= FOLL_LOCK;
+
 		if (!write && !(vma->vm_flags & VM_LOCKED) &&
 		    (!vma->vm_ops || (!vma->vm_ops->nopage &&
 					!vma->vm_ops->fault)))