From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756156Ab1LOPoE (ORCPT ); Thu, 15 Dec 2011 10:44:04 -0500 Received: from cavan.codon.org.uk ([93.93.128.6]:41828 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751477Ab1LOPoC (ORCPT ); Thu, 15 Dec 2011 10:44:02 -0500 Date: Thu, 15 Dec 2011 15:43:56 +0000 From: Matthew Garrett To: Mike Waychison Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com Subject: Re: [PATCH 3/4] EFI: Add support for variables longer than 1024 bytes Message-ID: <20111215154356.GA10486@srcf.ucam.org> References: <1323896791-10858-1-git-send-email-mjg@redhat.com> <1323896791-10858-4-git-send-email-mjg@redhat.com> <20111214223950.GA29264@srcf.ucam.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@cavan.codon.org.uk X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 14, 2011 at 02:57:51PM -0800, Mike Waychison wrote: > On Wed, Dec 14, 2011 at 2:39 PM, Matthew Garrett wrote: > > Hm. I think that'd only work if we expose a new interface. Writes would > > be easy enough to handle, but reads still need to work for old apps. > > Well,l we could *not* support returning all the data field for > datasize > 1024, and simply truncate the field. We are limited by > PAGE_SIZE by sysfs here anyway (so we don't really want to have a > variable size memcpy in efivar_show_raw). We'll pretty much definitely want to be able to read values > 1024 once people start shoving keys in there. The PAGE_SIZE limit is one that I'd forgotten about, though. -- Matthew Garrett | mjg59@srcf.ucam.org