From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030612Ab2HWP6W (ORCPT ); Thu, 23 Aug 2012 11:58:22 -0400 Received: from smtp.ctxuk.citrix.com ([62.200.22.115]:54850 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932715Ab2HWP6T (ORCPT ); Thu, 23 Aug 2012 11:58:19 -0400 X-IronPort-AV: E=Sophos;i="4.80,300,1344211200"; d="scan'208";a="14151319" Message-ID: <50364FE5.1070608@citrix.com> Date: Thu, 23 Aug 2012 16:44:37 +0100 From: Attilio Rao User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.16) Gecko/20111110 Icedove/3.0.11 MIME-Version: 1.0 To: Thomas Gleixner CC: "linux-kernel@vger.kernel.org" , "mingo@redhat.com" , "hpa@zytor.com" , "x86@kernel.org" , Stefano Stabellini , "konrad.wilk@oracle.com" Subject: Re: [PATCH v4 1/2] XEN/X86: Improve semantic support for x86_init.mapping.pagetable_reserve References: <1345648122-11935-1-git-send-email-attilio.rao@citrix.com> <1345648122-11935-2-git-send-email-attilio.rao@citrix.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/08/12 16:46, Thomas Gleixner wrote: > On Wed, 22 Aug 2012, Attilio Rao wrote: > > >> - Allow xen_mapping_pagetable_reserve() to handle a start different from >> pgt_buf_start, but still bigger than it. >> > What's the purpose of this and how is this going to be used and how is > it useful at all? > (Just replying here as all the other your comments are derivative) Looks like you are missing the whole point of the patch. What the patch is supposed to do is just to "enforce a correct semantic for the setup function" and not fix an actual problem found in the code. This means that after the patch you know exactly what expect in terms of semantic by the function and the callers will work following it. Otherwise, what could happen is that if one day for a reason or another begin start being different from pgt_buf_start this function will just break silently, reintroducing the original problem in a different form. I think this was clarified by the 0/2 but evidently you completely missed it. Attilio