Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030318Ab2EQQyL (ORCPT ); Thu, 17 May 2012 12:54:11 -0400 Received: from mailout4.w1.samsung.com ([210.118.77.14]:26780 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760366Ab2EQQx2 (ORCPT ); Thu, 17 May 2012 12:53:28 -0400 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: TEXT/PLAIN Date: Thu, 17 May 2012 18:53:05 +0200 From: Marek Szyprowski Subject: [PATCH 2/3] ARM: dma-mapping: add support for DMA_ATTR_NO_KERNEL_MAPPING attribute In-reply-to: <1337273586-11089-1-git-send-email-m.szyprowski@samsung.com> To: linux-arm-kernel@lists.infradead.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Marek Szyprowski , Kyungmin Park , Arnd Bergmann , Russell King - ARM Linux , Chunsang Jeong , Krishna Reddy , Benjamin Herrenschmidt , Konrad Rzeszutek Wilk , Hiroshi Doyu , Subash Patel , Sumit Semwal , Abhinav Kochhar , Tomasz Stanislawski Message-id: <1337273586-11089-3-git-send-email-m.szyprowski@samsung.com> X-Mailer: git-send-email 1.7.10.1 References: <1337273586-11089-1-git-send-email-m.szyprowski@samsung.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2875 Lines: 82 This patch adds support for DMA_ATTR_NO_KERNEL_MAPPING attribute for IOMMU allocations, what let drivers to save precious kernel virtual address space for large buffers that are intended to be accessed only from userspace. This patch is heavily based on initial work kindly provided by Abhinav Kochhar . Signed-off-by: Marek Szyprowski --- arch/arm/mm/dma-mapping.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 2e98403..23d0ace 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -940,9 +940,13 @@ static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova, size_t si return 0; } -static struct page **__iommu_get_pages(void *cpu_addr) +static struct page **__iommu_get_pages(void *cpu_addr, struct dma_attrs *attrs) { struct vm_struct *area; + + if (dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) + return cpu_addr; + read_lock(&vmlist_lock); area = find_vm_area(cpu_addr); read_unlock(&vmlist_lock); @@ -969,6 +973,9 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size, if (*handle == DMA_ERROR_CODE) goto err_buffer; + if (dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) + return pages; + addr = __iommu_alloc_remap(pages, size, gfp, prot, __builtin_return_address(0)); if (!addr) @@ -989,7 +996,7 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma, { unsigned long uaddr = vma->vm_start; unsigned long usize = vma->vm_end - vma->vm_start; - struct page **pages = __iommu_get_pages(cpu_addr); + struct page **pages = __iommu_get_pages(cpu_addr, attrs); vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot); @@ -1016,7 +1023,7 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle, struct dma_attrs *attrs) { - struct page **pages = __iommu_get_pages(cpu_addr); + struct page **pages = __iommu_get_pages(cpu_addr, attrs); size = PAGE_ALIGN(size); if (!pages) { @@ -1026,8 +1033,11 @@ void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr, return; } - unmap_kernel_range((unsigned long)cpu_addr, size); - vunmap(cpu_addr); + if (!dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) { + unmap_kernel_range((unsigned long)cpu_addr, size); + vunmap(cpu_addr); + } + __iommu_remove_mapping(dev, handle, size); __iommu_free_buffer(dev, pages, size); } -- 1.7.10.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/