From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756995Ab0LIT7k (ORCPT ); Thu, 9 Dec 2010 14:59:40 -0500 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:37228 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756632Ab0LIT7j (ORCPT ); Thu, 9 Dec 2010 14:59:39 -0500 Date: Thu, 09 Dec 2010 12:00:06 -0800 (PST) Message-Id: <20101209.120006.189701386.davem@davemloft.net> To: nicolas.ferre@atmel.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [RFC PATCH] scatterlist: Initialize the dma_address field with invalid dma address From: David Miller In-Reply-To: <1291900514-7290-1-git-send-email-nicolas.ferre@atmel.com> References: <1291900514-7290-1-git-send-email-nicolas.ferre@atmel.com> X-Mailer: Mew version 6.3 on Emacs 23.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nicolas Ferre Date: Thu, 9 Dec 2010 14:15:14 +0100 > Initialize the the dma_address field so that it will be possible to test > its value while using scatterlists. This field will be compatible with > testing by dma_mapping_error(). > > Signed-off-by: Nicolas Ferre Please don't do this, it's unjustified and it's going to kill performance. Even if it were a good change, you should have used the invalid DMA address definition defined by various architectures instead of a constant. You should be aware of whether entries in a scatterlist have been setup by your code path.