From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 09/21] dma-iommu: refactor iommu_dma_get_sgtable Date: Tue, 9 Apr 2019 19:26:52 +0200 Message-ID: <20190409172652.GF14679@lst.de> References: <20190327080448.5500-1-hch@lst.de> <20190327080448.5500-10-hch@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Robin Murphy Cc: Christoph Hellwig , Joerg Roedel , Catalin Marinas , Will Deacon , Tom Lendacky , iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: iommu@lists.linux-foundation.org On Tue, Apr 09, 2019 at 04:49:30PM +0100, Robin Murphy wrote: >> *cpu_addr, >> + size_t size) >> +{ >> + unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; >> + struct vm_struct *area = find_vm_area(cpu_addr); >> + >> + if (WARN_ON(!area || !area->pages)) >> + return -ENXIO; >> + return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size, >> + GFP_KERNEL); >> +} >> + > > Is this complex enough to deserve being broken out? Really I'd prefer to > keep get_sgtable() as small and consolidated as possible so that it's that > much easier to delete in future :) Well, it is logically separate, and this keeps it tidy. But I agree with the long term goal of killing off this awkward API that should never have been added. > > I guess there is a certain symmetry with mmap(), so if that's the angle > you're dead set on, could we at least keep this guy down where > __iommu_dma_get_sgtable_page() was? It is up there so that we can reduce the number of ifdef blocks for dma remapping later on. 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,URIBL_BLOCKED,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 14319C10F0E for ; Tue, 9 Apr 2019 17:27:06 +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 E4A5D2133D for ; Tue, 9 Apr 2019 17:27:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E4A5D2133D 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 BCEAADDF; Tue, 9 Apr 2019 17:27:05 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 714E8DD2 for ; Tue, 9 Apr 2019 17:27:04 +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 113E276D for ; Tue, 9 Apr 2019 17:27:04 +0000 (UTC) Received: by newverein.lst.de (Postfix, from userid 2407) id 7CEBC68B02; Tue, 9 Apr 2019 19:26:52 +0200 (CEST) Date: Tue, 9 Apr 2019 19:26:52 +0200 From: Christoph Hellwig To: Robin Murphy Subject: Re: [PATCH 09/21] dma-iommu: refactor iommu_dma_get_sgtable Message-ID: <20190409172652.GF14679@lst.de> References: <20190327080448.5500-1-hch@lst.de> <20190327080448.5500-10-hch@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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: <20190409172652.bbiAKp0HYC7hmprYIUyc85LL53j0bFTjquJx7x7i4BQ@z> On Tue, Apr 09, 2019 at 04:49:30PM +0100, Robin Murphy wrote: >> *cpu_addr, >> + size_t size) >> +{ >> + unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; >> + struct vm_struct *area = find_vm_area(cpu_addr); >> + >> + if (WARN_ON(!area || !area->pages)) >> + return -ENXIO; >> + return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size, >> + GFP_KERNEL); >> +} >> + > > Is this complex enough to deserve being broken out? Really I'd prefer to > keep get_sgtable() as small and consolidated as possible so that it's that > much easier to delete in future :) Well, it is logically separate, and this keeps it tidy. But I agree with the long term goal of killing off this awkward API that should never have been added. > > I guess there is a certain symmetry with mmap(), so if that's the angle > you're dead set on, could we at least keep this guy down where > __iommu_dma_get_sgtable_page() was? It is up there so that we can reduce the number of ifdef blocks for dma remapping later on. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu