From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 14/26] iommu/dma: Refactor iommu_dma_free Date: Mon, 29 Apr 2019 21:16:22 +0200 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 Return-path: Content-Disposition: inline In-Reply-To: <20190429190348.GB5637@lst.de> 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 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)); } 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,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 C1884C04AA6 for ; Mon, 29 Apr 2019 19:16:42 +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 8510421655 for ; Mon, 29 Apr 2019 19:16:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8510421655 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 3D618DD9; Mon, 29 Apr 2019 19:16:42 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id E2C7FDA6 for ; Mon, 29 Apr 2019 19:16:40 +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 6D2CB875 for ; Mon, 29 Apr 2019 19:16:40 +0000 (UTC) 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 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-Disposition: inline In-Reply-To: <20190429190348.GB5637@lst.de> 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: <20190429191622.lgyDBaWtmmkmJAFJqS6VPueIAbfPXDnM9SAaLwZcPA8@z> 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)); } _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu