Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755568AbcKJLmK (ORCPT ); Thu, 10 Nov 2016 06:42:10 -0500 Received: from 8bytes.org ([81.169.241.247]:58847 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755344AbcKJLmJ (ORCPT ); Thu, 10 Nov 2016 06:42:09 -0500 Date: Thu, 10 Nov 2016 12:42:06 +0100 From: Joerg Roedel To: Robin Murphy Cc: Magnus Damm , iommu@lists.linux-foundation.org, laurent.pinchart+renesas@ideasonboard.com, geert+renesas@glider.be, linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, horms+renesas@verge.net.au, m.szyprowski@samsung.com Subject: Re: [PATCH v6 05/07] iommu/ipmmu-vmsa: Add new IOMMU_DOMAIN_DMA ops Message-ID: <20161110114206.GC9996@8bytes.org> References: <20161019233533.10506.16810.sendpatchset@little-apple> <20161019233623.10506.49016.sendpatchset@little-apple> <941ff264-8f9f-e0e6-2b50-bdd3e19946e5@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <941ff264-8f9f-e0e6-2b50-bdd3e19946e5@arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 834 Lines: 23 On Fri, Oct 21, 2016 at 06:52:53PM +0100, Robin Murphy wrote: > > -static struct iommu_domain *ipmmu_domain_alloc(unsigned type) > > -{ > > - if (type != IOMMU_DOMAIN_UNMANAGED) > > - return NULL; > > I *think* that if we did the initial check thus: > > if (type != IOMMU_DOMAIN_UNMANAGED || > (IS_ENABLED(CONFIG_IOMMU_DMA) && type != IOMMU_DOMAIN_DMA)) > return NULL; > > it shouldn't be necessary to split the function at all - we then just > wrap the {get,put}_cookie() bits in "if (type == IOMMU_DOMAIN_DMA)" and > in the 32-bit ARM case they just don't run as that can never be true. This would be a good improvement. Magnus, Robin, can either of you send a follow-on patch to implement this suggestion? I have applied these patches to my arm/renesas branch (not pushed yet). The patch can be based on it. Joerg