Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932227AbVJCLHv (ORCPT ); Mon, 3 Oct 2005 07:07:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932228AbVJCLHv (ORCPT ); Mon, 3 Oct 2005 07:07:51 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:51081 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S932227AbVJCLHu (ORCPT ); Mon, 3 Oct 2005 07:07:50 -0400 Subject: Re: [RFC][PATCH] SPI subsystem From: Arjan van de Ven To: Mark Underwood Cc: David Brownell , linux-kernel@vger.kernel.org, dpervushin@ru.mvista.com In-Reply-To: <20051003105748.213.qmail@web33014.mail.mud.yahoo.com> References: <20051003105748.213.qmail@web33014.mail.mud.yahoo.com> Content-Type: text/plain Date: Mon, 03 Oct 2005 13:07:36 +0200 Message-Id: <1128337656.17024.10.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-Spam-Score: 2.9 (++) X-Spam-Report: SpamAssassin version 3.0.4 on pentafluge.infradead.org summary: Content analysis details: (2.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.1 RCVD_IN_SORBS_DUL RBL: SORBS: sent directly from dynamic IP address [80.57.133.107 listed in dnsbl.sorbs.net] 2.8 RCVD_IN_DSBL RBL: Received via a relay in list.dsbl.org [] X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 913 Lines: 24 On Mon, 2005-10-03 at 11:57 +0100, Mark Underwood wrote: > > > > > Hmm, using local variables for messages, so DMA adapter drivers have > > > > > to check if this is non-kmalloc'ed space (how?) > > > > > > > > They can't check that. It turns out that most current Linuxes > > > > have no issues DMAing a few bytes from the stack. > > > > > > Will the DMA remapping calls work with data from the stack? > > > > On "most current Linuxes" yes. All I know about, in fact. > > But it's not guaranteed. > > OK. Thanks please NEVER EVER do dma from or to a stack variable. It's not allowed on all architectures and it is really really bad practice in general anyway. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/