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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,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 AB9EEC43219 for ; Mon, 29 Apr 2019 19:16:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 76E7420675 for ; Mon, 29 Apr 2019 19:16:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729272AbfD2TQl (ORCPT ); Mon, 29 Apr 2019 15:16:41 -0400 Received: from verein.lst.de ([213.95.11.211]:40656 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728928AbfD2TQl (ORCPT ); Mon, 29 Apr 2019 15:16:41 -0400 Received: by newverein.lst.de (Postfix, from userid 2407) id 00C1768AFE; Mon, 29 Apr 2019 21:16:22 +0200 (CEST) Date: Mon, 29 Apr 2019 21:16:22 +0200 From: Christoph Hellwig 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 Subject: Re: [PATCH 14/26] iommu/dma: Refactor iommu_dma_free Message-ID: <20190429191622.GD5637@lst.de> References: <20190422175942.18788-1-hch@lst.de> <20190422175942.18788-15-hch@lst.de> <8321a363-f448-3e48-48f6-58d2b44a2900@arm.com> <20190429190348.GB5637@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190429190348.GB5637@lst.de> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 29, 2019 at 09:03:48PM +0200, Christoph Hellwig wrote: > On Mon, Apr 29, 2019 at 02:59:43PM +0100, Robin Murphy wrote: > > Hmm, I do still prefer my original flow with the dma_common_free_remap() > > call right out of the way at the end rather than being a special case in > > the middle of all the page-freeing (which is the kind of existing > > complexity I was trying to eliminate). I guess you've done this to avoid > > having "if (!dma_release_from_contiguous(...))..." twice like I ended up > > with, which is fair enough I suppose - once we manage to solve the new > > dma_{alloc,free}_contiguous() interface that may tip the balance so I can > > always revisit this then. > > Ok, I'll try to accomodate that with a minor rework. Does this look reasonable? diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 5b2a2bf44078..f884d22b1388 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -921,7 +921,7 @@ static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr, { size_t alloc_size = PAGE_ALIGN(size); int count = alloc_size >> PAGE_SHIFT; - struct page *page = NULL; + struct page *page = NULL, **pages = NULL; __iommu_dma_unmap(dev, handle, size); @@ -934,19 +934,17 @@ static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr, * If it the address is remapped, then it's either non-coherent * or highmem CMA, or an iommu_dma_alloc_remap() construction. */ - struct page **pages = __iommu_dma_get_pages(cpu_addr); - - if (pages) - __iommu_dma_free_pages(pages, count); - else + pages = __iommu_dma_get_pages(cpu_addr); + if (!pages) page = vmalloc_to_page(cpu_addr); - dma_common_free_remap(cpu_addr, alloc_size, VM_USERMAP); } else { /* Lowmem means a coherent atomic or CMA allocation */ page = virt_to_page(cpu_addr); } + if (pages) + __iommu_dma_free_pages(pages, count); if (page && !dma_release_from_contiguous(dev, page, count)) __free_pages(page, get_order(alloc_size)); }