From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 12/21] dma-iommu: factor atomic pool allocations into helpers Date: Fri, 19 Apr 2019 11:07:59 +0200 Message-ID: <20190419090759.GA22885@lst.de> References: <20190327080448.5500-1-hch@lst.de> <20190327080448.5500-13-hch@lst.de> <20190410061157.GA5278@lst.de> <20190417063358.GA24139@lst.de> <83615173-a8b4-e0eb-bac3-1a58d61ea4ef@arm.com> <20190418163512.GA25347@lst.de> <433dec64-ef15-b31d-ace4-4c72b81d2942@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <433dec64-ef15-b31d-ace4-4c72b81d2942@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Robin Murphy Cc: Tom Lendacky , Catalin Marinas , Joerg Roedel , Will Deacon , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Christoph Hellwig , linux-arm-kernel@lists.infradead.org List-Id: iommu@lists.linux-foundation.org On Thu, Apr 18, 2019 at 05:41:00PM +0100, Robin Murphy wrote: >> From a very high level POV this looks ok, but sometimes a bit to >> convoluted to me. The major issue why I went with the version I posted >> is that I can cleanly ifdef out the remap code in just a few sections. >> In this version it is spread out a lot more, and the use of IS_ENABLED >> means that we'd need a lot more stubs for functionality that won't >> ever be called but needs to be compilable. > > What functionality do you have planned in that regard? I did do a quick > build test of my arm64 config with DMA_DIRECT_REMAP hacked out, and > dma-iommu.o appeared to link OK (although other bits of arm64 and > dma-direct didn't, as expected). I will try x86 with IOMMU_DMA to make > sure, though. Yeah, this seems to actually work, there just is a huge chunk of remapping that is hopefully discarded by the compiler even without the ifdefs. 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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 9D416C282DA for ; Fri, 19 Apr 2019 09:08:28 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 775EE218CD for ; Fri, 19 Apr 2019 09:08:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 775EE218CD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 5F4C8230D; Fri, 19 Apr 2019 09:08:28 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 771AD2308 for ; Fri, 19 Apr 2019 09:08:15 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from newverein.lst.de (verein.lst.de [213.95.11.211]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 14BF5466 for ; Fri, 19 Apr 2019 09:08:15 +0000 (UTC) Received: by newverein.lst.de (Postfix, from userid 2407) id 3141F68B20; Fri, 19 Apr 2019 11:08:00 +0200 (CEST) Date: Fri, 19 Apr 2019 11:07:59 +0200 From: Christoph Hellwig To: Robin Murphy Subject: Re: [PATCH 12/21] dma-iommu: factor atomic pool allocations into helpers Message-ID: <20190419090759.GA22885@lst.de> References: <20190327080448.5500-1-hch@lst.de> <20190327080448.5500-13-hch@lst.de> <20190410061157.GA5278@lst.de> <20190417063358.GA24139@lst.de> <83615173-a8b4-e0eb-bac3-1a58d61ea4ef@arm.com> <20190418163512.GA25347@lst.de> <433dec64-ef15-b31d-ace4-4c72b81d2942@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <433dec64-ef15-b31d-ace4-4c72b81d2942@arm.com> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: Tom Lendacky , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Christoph Hellwig , linux-arm-kernel@lists.infradead.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org Message-ID: <20190419090759.zIhB1ExvANz2cyx84p64Px8E_vdfUOuMHbCzjTcG87M@z> On Thu, Apr 18, 2019 at 05:41:00PM +0100, Robin Murphy wrote: >> From a very high level POV this looks ok, but sometimes a bit to >> convoluted to me. The major issue why I went with the version I posted >> is that I can cleanly ifdef out the remap code in just a few sections. >> In this version it is spread out a lot more, and the use of IS_ENABLED >> means that we'd need a lot more stubs for functionality that won't >> ever be called but needs to be compilable. > > What functionality do you have planned in that regard? I did do a quick > build test of my arm64 config with DMA_DIRECT_REMAP hacked out, and > dma-iommu.o appeared to link OK (although other bits of arm64 and > dma-direct didn't, as expected). I will try x86 with IOMMU_DMA to make > sure, though. Yeah, this seems to actually work, there just is a huge chunk of remapping that is hopefully discarded by the compiler even without the ifdefs. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu