Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754287Ab0BZVFF (ORCPT ); Fri, 26 Feb 2010 16:05:05 -0500 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:58641 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753814Ab0BZVFC (ORCPT ); Fri, 26 Feb 2010 16:05:02 -0500 Date: Fri, 26 Feb 2010 21:00:30 +0000 From: Russell King - ARM Linux To: Catalin Marinas Cc: Benjamin Herrenschmidt , Matthew Dharm , linux-usb@vger.kernel.org, "Mankad,Maulik Ojas" , Sergei Shtylyov , Ming Lei , Sebastian Siewior , Oliver Neukum , linux-kernel , "Shilimkar,Santosh" , Pavel Machek , Greg KH , linux-arm-kernel , James Bottomley Subject: Re: USB mass storage and ARM cache coherency Message-ID: <20100226210030.GC23933@n2100.arm.linux.org.uk> References: <1266979632.23523.1668.camel@pasglop> <1267201521.14703.50.camel@e102109-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1267201521.14703.50.camel@e102109-lin.cambridge.arm.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 778 Lines: 14 On Fri, Feb 26, 2010 at 04:25:21PM +0000, Catalin Marinas wrote: > For mmap'ed pages (and present in the page cache), is it guaranteed that > the HCD driver won't write to it once it has been mapped into user > space? If that's the case, it may solve the problem by just reversing > the meaning of PG_arch_1 on ARM and assume that a newly allocated page > has dirty D-cache by default. I guess we could also set PG_arch_1 in the DMA API as well, to avoid the unnecessary D cache flushing when clean pages get mapped into userspace. -- 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/