From mboxrd@z Thu Jan  1 00:00:00 1970
From: corbet@lwn.net (Jonathan Corbet)
Subject: Re: [PATCH 3/18] allow callers of seq_open do allocation themselves
Date: Tue, 08 Nov 2005 13:33:37 -0700
Message-ID: <20051108203337.15569.qmail@lwn.net>
References: <E1EZInj-0001Eh-9T@ZenIV.linux.org.uk>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Return-path: <linux-kernel-owner+glk-linux-kernel-3=40m.gmane.org-S964996AbVKHUdj@vger.kernel.org>
To: Al Viro <viro@ftp.linux.org.uk>
In-reply-to: Your message of "Tue, 08 Nov 2005 02:01:31 GMT."
             <E1EZInj-0001Eh-9T@ZenIV.linux.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: linux-fsdevel.vger.kernel.org

Al Viro <viro@ftp.linux.org.uk> wrote:

> Allows caller of seq_open() to kmalloc() seq_file + whatever else they want
> and set ->private_data to it.  seq_open() will then abstain from doing
> allocation itself.

It looks like seq_release() frees the structure regardless of where it
came from.  So the seq_file structure must be the first field in
whatever structure contains it, and one has to hope that won't change in
the future.  Is that really the way the interface was meant to work?

jon