alloc_file(): switch to passing O_... flags instead of FMODE_... mode

... so that it could set both ->f_flags and ->f_mode, without callers
having to set ->f_flags manually.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/aio.c b/fs/aio.c
index e1d2012..9eea538 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -234,13 +234,9 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
 	path.mnt = mntget(aio_mnt);
 
 	d_instantiate(path.dentry, inode);
-	file = alloc_file(&path, FMODE_READ | FMODE_WRITE, &aio_ring_fops);
-	if (IS_ERR(file)) {
+	file = alloc_file(&path, O_RDWR, &aio_ring_fops);
+	if (IS_ERR(file))
 		path_put(&path);
-		return file;
-	}
-
-	file->f_flags = O_RDWR;
 	return file;
 }