From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753229AbbHMR6U (ORCPT ); Thu, 13 Aug 2015 13:58:20 -0400 Received: from verein.lst.de ([213.95.11.211]:49541 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751862AbbHMR6R (ORCPT ); Thu, 13 Aug 2015 13:58:17 -0400 Date: Thu, 13 Aug 2015 19:58:14 +0200 From: Christoph Hellwig To: Russell King - ARM Linux Cc: Christoph Hellwig , akpm@linux-foundation.org, arnd@arndb.de, catalin.marinas@arm.com, will.deacon@arm.com, ysato@users.sourceforge.jp, monstr@monstr.eu, jonas@southpole.se, cmetcalf@ezchip.com, gxt@mprc.pku.edu.cn, x86@kernel.org, linux-alpha@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-mips@linux-mips.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/5] dma-mapping: consolidate dma_set_mask Message-ID: <20150813175814.GB21103@lst.de> References: <1439478248-15183-1-git-send-email-hch@lst.de> <1439478248-15183-6-git-send-email-hch@lst.de> <20150813152505.GR7557@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150813152505.GR7557@n2100.arm.linux.org.uk> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 13, 2015 at 04:25:05PM +0100, Russell King - ARM Linux wrote: > On Thu, Aug 13, 2015 at 05:04:08PM +0200, Christoph Hellwig wrote: > > diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c > > index 1143c4d..260f52a 100644 > > --- a/arch/arm/common/dmabounce.c > > +++ b/arch/arm/common/dmabounce.c > > @@ -440,14 +440,6 @@ static void dmabounce_sync_for_device(struct device *dev, > > arm_dma_ops.sync_single_for_device(dev, handle, size, dir); > > } > > > > -static int dmabounce_set_mask(struct device *dev, u64 dma_mask) > > -{ > > - if (dev->archdata.dmabounce) > > - return 0; > > - > > - return arm_dma_ops.set_dma_mask(dev, dma_mask); > > Are you sure about this? A user of dmabounce gets to request any mask > with the original code (even though it was never written back... which > is a separate bug.) After this, it seems that this will get limited > by the dma_supported() check. As this old code is about bouncing any > buffer into DMA-able memory, it doesn't care about the DMA mask. I think you're right. With the default dma_supported implementation it would be fine, but ARM uses a custom one. I'll keep the arm specific dma_set_mask implementation for the next round.