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,URIBL_BLOCKED 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 310ADC04EB8 for ; Fri, 30 Nov 2018 19:05:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0137E20673 for ; Fri, 30 Nov 2018 19:05:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0137E20673 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727050AbeLAGP7 (ORCPT ); Sat, 1 Dec 2018 01:15:59 -0500 Received: from foss.arm.com ([217.140.101.70]:35196 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726554AbeLAGP7 (ORCPT ); Sat, 1 Dec 2018 01:15:59 -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 860A61684; Fri, 30 Nov 2018 11:05:43 -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 27EFC3F575; Fri, 30 Nov 2018 11:05:42 -0800 (PST) Subject: Re: [PATCH 6/9] dma-remap: support DMA_ATTR_NO_KERNEL_MAPPING To: Christoph Hellwig , iommu@lists.linux-foundation.org Cc: Catalin Marinas , Will Deacon , Guo Ren , Laura Abbott , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20181105121931.13481-1-hch@lst.de> <20181105121931.13481-7-hch@lst.de> From: Robin Murphy Message-ID: Date: Fri, 30 Nov 2018 19:05:40 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181105121931.13481-7-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 05/11/2018 12:19, Christoph Hellwig wrote: > Do not waste vmalloc space on allocations that do not require a mapping > into the kernel address space. > > Signed-off-by: Christoph Hellwig > --- > kernel/dma/remap.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c > index 8f1fca34b894..10a545126b0b 100644 > --- a/kernel/dma/remap.c > +++ b/kernel/dma/remap.c > @@ -200,7 +200,8 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, > > size = PAGE_ALIGN(size); > > - if (!gfpflags_allow_blocking(flags)) { > + if (!gfpflags_allow_blocking(flags) && > + !(attrs & DMA_ATTR_NO_KERNEL_MAPPING)) { > ret = dma_alloc_from_pool(size, &page, flags); > if (!ret) > return NULL; > @@ -215,6 +216,9 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, > /* remove any dirty cache lines on the kernel alias */ > arch_dma_prep_coherent(page, size); > > + if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) > + return page; /* opaqueue cookie */ Best to preempt the inevitable patch fixing that typo in 3 months' time. Otherwise, Reviewed-by: Robin Murphy > + > /* create a coherent mapping */ > ret = dma_common_contiguous_remap(page, size, VM_USERMAP, > arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs), > @@ -227,7 +231,10 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, > void arch_dma_free(struct device *dev, size_t size, void *vaddr, > dma_addr_t dma_handle, unsigned long attrs) > { > - if (!dma_free_from_pool(vaddr, PAGE_ALIGN(size))) { > + if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) { > + /* vaddr is a struct page cookie, not a kernel address */ > + __dma_direct_free_pages(dev, size, vaddr); > + } else if (!dma_free_from_pool(vaddr, PAGE_ALIGN(size))) { > phys_addr_t phys = dma_to_phys(dev, dma_handle); > struct page *page = pfn_to_page(__phys_to_pfn(phys)); > >