From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760725Ab2D0QYm (ORCPT ); Fri, 27 Apr 2012 12:24:42 -0400 Received: from terminus.zytor.com ([198.137.202.10]:38411 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760704Ab2D0QYk (ORCPT ); Fri, 27 Apr 2012 12:24:40 -0400 Message-ID: <4F9AC806.60608@zytor.com> Date: Fri, 27 Apr 2012 09:23:34 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: Will Deacon CC: linux-kernel@vger.kernel.org, uclinux-dist-devel@blackfin.uclinux.org, Arnd Bergmann , Mike Frysinger Subject: Re: [PATCH 1/2] asm-generic: io: remove {read,write} string functions References: <1335523376-14695-1-git-send-email-will.deacon@arm.com> In-Reply-To: <1335523376-14695-1-git-send-email-will.deacon@arm.com> X-Enigmail-Version: 1.4.1 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 On 04/27/2012 03:42 AM, Will Deacon wrote: > The {read,write}s{b,w,l} functions are not defined across all > architectures and therefore shouldn't be used by portable drivers. We > should encourage driver writers to use the io{read,write}{8,16,32}_rep > functions instead. Why is that? ioread/write are great if the address space is undefined, but do we need the extra overhead in any other cases? -hpa