From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10D12C282C2 for ; Wed, 6 Feb 2019 15:08:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DBA822175B for ; Wed, 6 Feb 2019 15:08:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731076AbfBFPIa (ORCPT ); Wed, 6 Feb 2019 10:08:30 -0500 Received: from foss.arm.com ([217.140.101.70]:54170 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730230AbfBFPI3 (ORCPT ); Wed, 6 Feb 2019 10:08:29 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5D29280D; Wed, 6 Feb 2019 07:08:29 -0800 (PST) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 04B8A3F675; Wed, 6 Feb 2019 07:08:27 -0800 (PST) Subject: Re: [PATCH 02/19] dma-iommu: cleanup dma-iommu.h To: Christoph Hellwig Cc: Joerg Roedel , Catalin Marinas , Will Deacon , Tom Lendacky , iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20190114094159.27326-1-hch@lst.de> <20190114094159.27326-3-hch@lst.de> <3f78b779-4360-1204-e942-39a8a81759c7@arm.com> <20190201161305.GI6532@lst.de> From: Robin Murphy Message-ID: <5bf081c2-2b8c-d3d1-c93e-468c8f3cef67@arm.com> Date: Wed, 6 Feb 2019 15:08:26 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190201161305.GI6532@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/02/2019 16:13, Christoph Hellwig wrote: > On Fri, Feb 01, 2019 at 02:47:17PM +0000, Robin Murphy wrote: >> On 14/01/2019 09:41, Christoph Hellwig wrote: >>> No need for a __KERNEL__ guard outside uapi, make sure we pull in the >>> includes unconditionally so users can rely on it, and add a missing >>> comment describing the #else cpp statement. Last but not least include >>> instead of the asm version, which is frowned upon. >> >> I think the __KERNEL__ and asm/errno.h slip-ups are things I cargo-culted >> from the arch code as a fresh-faced noob yet to learn the finer details, so >> ack for those parts. The forward-declarations, though, were a deliberate >> effort to minimise header dependencies and compilation bloat for includers >> who absolutely wouldn't care, and specifically to try to avoid setting >> transitive include expectations since they always seem to end up breaking >> someone's config somewhere down the line. Admittedly this little backwater >> is hardly comparable to the likes of the sched.h business, but I'm still >> somewhat on the fence about that change :/ > > As far as I can tell almost all users of linux/dma-iommu.h require > CONFIG_DMA_IOMMU to be enabled anyway.. Other than dma-iommu.c itself, none of them *require* it - only arch/arm64 selects it (the one from MTK_IOMMU is just bogus), and a lot of the drivers also build for at least one other architecture (and/or arm64 with !IOMMU_API). Either way, I have no vehement objection to the change, I just don't see any positive value in it. Robin.