direct_IO: remove rw from a_ops->direct_IO()

Now that no one is using rw, remove it completely.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/page_io.c b/mm/page_io.c
index a96c856..6424869 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -277,9 +277,7 @@
 
 		set_page_writeback(page);
 		unlock_page(page);
-		ret = mapping->a_ops->direct_IO(ITER_BVEC | WRITE,
-						&kiocb, &from,
-						kiocb.ki_pos);
+		ret = mapping->a_ops->direct_IO(&kiocb, &from, kiocb.ki_pos);
 		if (ret == PAGE_SIZE) {
 			count_vm_event(PSWPOUT);
 			ret = 0;