Remove rw from {,__,do_}blockdev_direct_IO()

Most filesystems call through to these at some point, so we'll start
here.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index fe6634d..59983a1 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -1095,9 +1095,8 @@
 			truncate_inode_pages_range(mapping, lstart, end);
 	}
 
-	rv = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev,
-				  iter, offset,
-				  gfs2_get_block_direct, NULL, NULL, 0);
+	rv = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
+				  offset, gfs2_get_block_direct, NULL, NULL, 0);
 out:
 	gfs2_glock_dq(&gh);
 	gfs2_holder_uninit(&gh);