From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264537AbTFTTnH (ORCPT ); Fri, 20 Jun 2003 15:43:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264538AbTFTTnH (ORCPT ); Fri, 20 Jun 2003 15:43:07 -0400 Received: from wohnheim.fh-wedel.de ([195.37.86.122]:29648 "EHLO wohnheim.fh-wedel.de") by vger.kernel.org with ESMTP id S264537AbTFTTnE (ORCPT ); Fri, 20 Jun 2003 15:43:04 -0400 Date: Fri, 20 Jun 2003 21:56:58 +0200 From: =?iso-8859-1?Q?J=F6rn?= Engel To: "David S. Miller" Cc: linux-kernel@vger.kernel.org, jmorris@intercode.com.au, dwmw2@infradead.org Subject: Re: [RFC] Breaking data compatibility with userspace bzlib Message-ID: <20030620195658.GB22732@wohnheim.fh-wedel.de> References: <20030620185915.GD28711@wohnheim.fh-wedel.de> <20030620.124510.28800472.davem@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20030620.124510.28800472.davem@redhat.com> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 20 June 2003 12:45:10 -0700, David S. Miller wrote: > From: Jörn Engel > Date: Fri, 20 Jun 2003 20:59:15 +0200 > > The whole interface of the bzlib was modelled after the zlib > interface. > > The zlib interface is actually problematic, it doesn't allow > handling of scatter-gather lists on input or output for example. > > Therefore we couldn't make the compress cryptolib interface > take scatterlists elements either, which is a huge problem. Is there a reason to use the zlib and nothing but the zlib for the cryptolib? RFCs 1950 - 1952? Or would any form of compression do, in principle at least? In the worst case, I consider it not too hard to add a wrapper interface to the zlib to do the scatter-gather handling. Actually going deeply into the guts of the zlib is not good for a kernel hackers sanity though. The massive use of macros with magic knowledge of the surrounding functions is - well - interesting. Jörn -- If you're willing to restrict the flexibility of your approach, you can almost always do something better. -- John Carmack