dma-mapping: move dma_common_{mmap,get_sgtable} out of mapping.c (545d2927) · Commits · 戴 / test

kernel/dma/Makefile

+1 −0

Original line number	Diff line number	Diff line
		# SPDX-License-Identifier: GPL-2.0

		obj-$(CONFIG_HAS_DMA) += mapping.o direct.o
		obj-$(CONFIG_DMA_OPS) += ops_helpers.o
		obj-$(CONFIG_DMA_OPS) += dummy.o
		obj-$(CONFIG_DMA_CMA) += contiguous.o
		obj-$(CONFIG_DMA_DECLARE_COHERENT) += coherent.o

kernel/dma/mapping.c

+1 −46

Original line number	Diff line number	Diff line
		@@ -8,7 +8,7 @@
		#include <linux/memblock.h> /* for max_pfn */
		#include <linux/acpi.h>
		#include <linux/dma-direct.h>
		#include <linux/dma-noncoherent.h>
		#include <linux/dma-mapping.h>
		#include <linux/export.h>
		#include <linux/gfp.h>
		#include <linux/of_device.h>
		@@ -295,22 +295,6 @@ void dma_sync_sg_for_device(struct device dev, struct scatterlist sg,
		}
		EXPORT_SYMBOL(dma_sync_sg_for_device);

		/*
		* Create scatter-list for the already allocated DMA buffer.
		*/
		int dma_common_get_sgtable(struct device dev, struct sg_table sgt,
		void *cpu_addr, dma_addr_t dma_addr, size_t size,
		unsigned long attrs)
		{
		struct page *page = virt_to_page(cpu_addr);
		int ret;

		ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
		if (!ret)
		sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
		return ret;
		}

		/*
		* The whole dma_get_sgtable() idea is fundamentally unsafe - it seems
		* that the intention is to allow exporting memory allocated via the
		@@ -358,35 +342,6 @@ pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs)
		}
		#endif /* CONFIG_MMU */

		/*
		* Create userspace mapping for the DMA-coherent memory.
		*/
		int dma_common_mmap(struct device dev, struct vm_area_struct vma,
		void *cpu_addr, dma_addr_t dma_addr, size_t size,
		unsigned long attrs)
		{
		#ifdef CONFIG_MMU
		unsigned long user_count = vma_pages(vma);
		unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
		unsigned long off = vma->vm_pgoff;
		int ret = -ENXIO;

		vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);

		if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
		return ret;

		if (off >= count \|\| user_count > count - off)
		return -ENXIO;

		return remap_pfn_range(vma, vma->vm_start,
		page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
		user_count << PAGE_SHIFT, vma->vm_page_prot);
		#else
		return -ENXIO;
		#endif /* CONFIG_MMU */
		}

		/**
		* dma_can_mmap - check if a given device supports dma_mmap_*
		* @dev: device to check

kernel/dma/ops_helpers.c

0 → 100644

+51 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		/*
		* Helpers for DMA ops implementations. These generally rely on the fact that
		* the allocated memory contains normal pages in the direct kernel mapping.
		*/
		#include <linux/dma-noncoherent.h>

		/*
		* Create scatter-list for the already allocated DMA buffer.
		*/
		int dma_common_get_sgtable(struct device dev, struct sg_table sgt,
		void *cpu_addr, dma_addr_t dma_addr, size_t size,
		unsigned long attrs)
		{
		struct page *page = virt_to_page(cpu_addr);
		int ret;

		ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
		if (!ret)
		sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
		return ret;
		}

		/*
		* Create userspace mapping for the DMA-coherent memory.
		*/
		int dma_common_mmap(struct device dev, struct vm_area_struct vma,
		void *cpu_addr, dma_addr_t dma_addr, size_t size,
		unsigned long attrs)
		{
		#ifdef CONFIG_MMU
		unsigned long user_count = vma_pages(vma);
		unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
		unsigned long off = vma->vm_pgoff;
		int ret = -ENXIO;

		vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);

		if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
		return ret;

		if (off >= count \|\| user_count > count - off)
		return -ENXIO;

		return remap_pfn_range(vma, vma->vm_start,
		page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
		user_count << PAGE_SHIFT, vma->vm_page_prot);
		#else
		return -ENXIO;
		#endif /* CONFIG_MMU */
		}

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