Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262007AbVBJBms (ORCPT ); Wed, 9 Feb 2005 20:42:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262008AbVBJBms (ORCPT ); Wed, 9 Feb 2005 20:42:48 -0500 Received: from mx1.redhat.com ([66.187.233.31]:44762 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S262007AbVBJBmq (ORCPT ); Wed, 9 Feb 2005 20:42:46 -0500 Date: Wed, 9 Feb 2005 20:42:37 -0500 (EST) From: James Morris X-X-Sender: jmorris@thoron.boston.redhat.com To: Fruhwirth Clemens cc: Andrew Morton , , , "David S. Miller" , "Adam J. Richter" Subject: Re: [PATCH 01/04] Adding cipher mode context information to crypto_tfm In-Reply-To: <1107997358.7645.24.camel@ghanima> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1034 Lines: 31 On Thu, 10 Feb 2005, Fruhwirth Clemens wrote: > Because a tweak is different from an IV. There can be an arbitrary > number of tweaks. For instance, EME takes 1 tweak per 512 bytes. If you > have a 4k page to encrypt, you have to process 8 tweaks of whatever > size. > Therefore, you need 3 scatterlists: src, dst and the running along > tweak. The purpose of the scatterlists is to be able to process discontigous data at the page level. The tweak, as I understand it, is something which you generate, and it is not inherently likely to be page-level clumps of data. It does not ever need to be kmapped. What you really need to do is use an array for the tweak (or possibly a structure which maintains state about it if needed). - James -- James Morris - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/