From: David Brownell Subject: Re: [PATCH] jffs2 summary allocation Date: Fri, 4 Apr 2008 16:58:38 -0700 Message-ID: <200804041658.38499.david-b@pacbell.net> References: <713171.37644.qm@web26213.mail.ukl.yahoo.com> <200804041609.41092.david-b@pacbell.net> <1207351282.3224.79.camel@vader.jdub.homelinux.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Michael Trimarchi , spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Andrew Morton , dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, linux-arm-kernel-xIg/pKzrS19vn6HldHNs0ANdhmdF6hFW@public.gmane.org To: Josh Boyer Return-path: In-Reply-To: <1207351282.3224.79.camel-ao9So7SQ8LBXjJKHA5322XviChZXdy27@public.gmane.org> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.vger.kernel.org On Friday 04 April 2008, Josh Boyer wrote: > = > > =A0 ... This means specifically that you may _not_ use the > > =A0 memory/addresses returned from vmalloc() for DMA. =A0... > > = > > So I'm rather surprised to see *ANY* kernel code trying to do > > that. =A0That rule has been in effect for many, many years now. > = > I don't think it was intentional. =A0You're going through several layers > here: > = > JFFS2 -> mtd parts -> mtd dataflash -> atmel_spi. > = > Typically MTD drivers aren't doing DMAs to flash and JFFS2 has no idea > which particular chip driver is being used because it's abstracted by > MTD. That's true ... although I can imagine using DMA to avoid dcache trashing if its setup cost is low enough, with either NAND or NOR chips. Still: in this context vmalloc() is wrong. - Dave ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference = Register now and save $200. Hurry, offer ends at 11:59 p.m., = Monday, April 7! Use priority code J8TLD2. = http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/java= one