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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 5AFB9C282CE for ; Tue, 9 Apr 2019 15:49:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 284F52133D for ; Tue, 9 Apr 2019 15:49:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726624AbfDIPte (ORCPT ); Tue, 9 Apr 2019 11:49:34 -0400 Received: from foss.arm.com ([217.140.101.70]:40194 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726415AbfDIPtd (ORCPT ); Tue, 9 Apr 2019 11:49:33 -0400 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 DDD3815AB; Tue, 9 Apr 2019 08:49:32 -0700 (PDT) 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 85F423F68F; Tue, 9 Apr 2019 08:49:31 -0700 (PDT) Subject: Re: [PATCH 09/21] dma-iommu: refactor iommu_dma_get_sgtable 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: <20190327080448.5500-1-hch@lst.de> <20190327080448.5500-10-hch@lst.de> From: Robin Murphy Message-ID: Date: Tue, 9 Apr 2019 16:49:30 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190327080448.5500-10-hch@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 27/03/2019 08:04, Christoph Hellwig wrote: > Move the vm_area handling into a new iommu_dma_get_sgtable_remap helper. > > Inline __iommu_dma_get_sgtable_page into the main function to simplify > the code flow a bit. > > Signed-off-by: Christoph Hellwig > --- > drivers/iommu/dma-iommu.c | 54 +++++++++++++++++---------------------- > 1 file changed, 24 insertions(+), 30 deletions(-) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index 43bd3c7e0f6b..57f2d8621112 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -625,6 +625,18 @@ static int iommu_dma_mmap_remap(void *cpu_addr, size_t size, > return ret; > } > > +static int iommu_dma_get_sgtable_remap(struct sg_table *sgt, void *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 :) 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? Robin. > static void iommu_dma_sync_single_for_cpu(struct device *dev, > dma_addr_t dma_handle, size_t size, enum dma_data_direction dir) > { > @@ -1084,42 +1096,24 @@ static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma, > vma_pages(vma) << PAGE_SHIFT, vma->vm_page_prot); > } > > -static int __iommu_dma_get_sgtable_page(struct sg_table *sgt, struct page *page, > - size_t size) > -{ > - int ret = sg_alloc_table(sgt, 1, GFP_KERNEL); > - > - if (!ret) > - sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0); > - return ret; > -} > - > static int iommu_dma_get_sgtable(struct device *dev, struct sg_table *sgt, > void *cpu_addr, dma_addr_t dma_addr, size_t size, > unsigned long attrs) > { > - unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; > - struct vm_struct *area = find_vm_area(cpu_addr); > - > - if (!is_vmalloc_addr(cpu_addr)) { > - struct page *page = virt_to_page(cpu_addr); > - return __iommu_dma_get_sgtable_page(sgt, page, size); > - } > - > - if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) { > - /* > - * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped, > - * hence in the vmalloc space. > - */ > - struct page *page = vmalloc_to_page(cpu_addr); > - return __iommu_dma_get_sgtable_page(sgt, page, size); > - } > + struct page *page; > + int ret; > > - if (WARN_ON(!area || !area->pages)) > - return -ENXIO; > + if (is_vmalloc_addr(cpu_addr)) { > + if (!(attrs & DMA_ATTR_FORCE_CONTIGUOUS)) > + return iommu_dma_get_sgtable_remap(sgt, cpu_addr, size); > + page = vmalloc_to_page(cpu_addr); > + } else > + page = virt_to_page(cpu_addr); > > - return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size, > - GFP_KERNEL); > + ret = sg_alloc_table(sgt, 1, GFP_KERNEL); > + if (!ret) > + sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0); > + return ret; > } > > static const struct dma_map_ops iommu_dma_ops = { >