From: Hugh Dickins <hugh@veritas.com>

My recent mm patch to give pte_ERROR in do_file_page unless VM_NONLINEAR
was incorrect.  I was forgetting Oleg's patch to the populate functions,
which forces install_file_pte when MAP_POPULATE + MAP_NONBLOCK but page
not in cache (in case an existing nonlinear entry needs removing).  But
that's only necessary in the VM_NONLINEAR case: let's keep the strict
check in do_file_page, and adjust filemap_populate and shmem_populate.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Index: linux-2.6/mm/filemap.c
===================================================================
--- linux-2.6.orig/mm/filemap.c
+++ linux-2.6/mm/filemap.c
@@ -1520,7 +1520,7 @@ repeat:
 			page_cache_release(page);
 			return err;
 		}
-	} else {
+	} else if (vma->vm_flags & VM_NONLINEAR) {
 		/* No page was found just because we can't read it in now (being
 		 * here implies nonblock != 0), but the page may exist, so set
 		 * the PTE to fault it in later. */
Index: linux-2.6/mm/shmem.c
===================================================================
--- linux-2.6.orig/mm/shmem.c
+++ linux-2.6/mm/shmem.c
@@ -1201,7 +1201,7 @@ static int shmem_populate(struct vm_area
 				page_cache_release(page);
 				return err;
 			}
-		} else {
+		} else if (vma->vm_flags & VM_NONLINEAR) {
 			/* No page was found just because we can't read it in
 			 * now (being here implies nonblock != 0), but the page
 			 * may exist, so set the PTE to fault it in later. */