From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754479AbYIHTl6 (ORCPT ); Mon, 8 Sep 2008 15:41:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752999AbYIHTlt (ORCPT ); Mon, 8 Sep 2008 15:41:49 -0400 Received: from gw.goop.org ([64.81.55.164]:54154 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751254AbYIHTls (ORCPT ); Mon, 8 Sep 2008 15:41:48 -0400 Message-ID: <48C57FF8.9080802@goop.org> Date: Mon, 08 Sep 2008 12:41:44 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: Ingo Molnar CC: Andi Kleen , linux-kernel@vger.kernel.org, "H. Peter Anvin" , Xen Devel Subject: Re: [PATCH 6 of 7] x86: use early_ioremap in __acpi_map_table References: <944fe7ea3da7707eb90f.1220826078@localhost> <20080907234418.GB26079@one.firstfloor.org> <48C46BCB.2060209@goop.org> <20080908142619.GA10580@elte.hu> In-Reply-To: <20080908142619.GA10580@elte.hu> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > uhm, there's a nasty trap in that route: it can potentially cause a lot > of breakage. > > It's not robust to assume that the ACPI code is sane wrt. > mapping/unmapping, because it currently simply doesnt rely on robust > unmapping (in the linear range). > > I tried it in the past and i found tons of crappy ACPI code all around > that just never unmapped tables. Leaking ACPI maps are hard to find as > well, and it can occur anytime during bootup. > Yes, you're right, it's a mess. I put a unmap and warning in there, but there's lots of acpi code which doesn't unmap after using its table. It doesn't seem to intermix using two tables, fortunately, so the "unmap previous" behaviour of __acpi_map_table works OK, at least as far as I can see. J