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a16c46c240
dma_common_contiguous_remap() is used to remap an "allocated contiguous region". Within a single allocation, there is no need to use nth_page() anymore. Neither the buddy, nor hugetlb, nor CMA will hand out problematic page ranges. Link: https://lkml.kernel.org/r/20250901150359.867252-24-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
73 lines
1.7 KiB
C
73 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2014 The Linux Foundation
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*/
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#include <linux/dma-map-ops.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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struct page **dma_common_find_pages(void *cpu_addr)
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{
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struct vm_struct *area = find_vm_area(cpu_addr);
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if (!area || !(area->flags & VM_DMA_COHERENT))
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return NULL;
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WARN(area->flags != VM_DMA_COHERENT,
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"unexpected flags in area: %p\n", cpu_addr);
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return area->pages;
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}
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/*
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* Remaps an array of PAGE_SIZE pages into another vm_area.
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* Cannot be used in non-sleeping contexts
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*/
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void *dma_common_pages_remap(struct page **pages, size_t size,
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pgprot_t prot, const void *caller)
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{
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void *vaddr;
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vaddr = vmap(pages, PAGE_ALIGN(size) >> PAGE_SHIFT,
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VM_DMA_COHERENT, prot);
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if (vaddr)
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find_vm_area(vaddr)->pages = pages;
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return vaddr;
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}
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/*
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* Remaps an allocated contiguous region into another vm_area.
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* Cannot be used in non-sleeping contexts
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*/
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void *dma_common_contiguous_remap(struct page *page, size_t size,
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pgprot_t prot, const void *caller)
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{
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int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
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struct page **pages;
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void *vaddr;
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int i;
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pages = kvmalloc_array(count, sizeof(struct page *), GFP_KERNEL);
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if (!pages)
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return NULL;
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for (i = 0; i < count; i++)
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pages[i] = page++;
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vaddr = vmap(pages, count, VM_DMA_COHERENT, prot);
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kvfree(pages);
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return vaddr;
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}
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/*
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* Unmaps a range previously mapped by dma_common_*_remap
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*/
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void dma_common_free_remap(void *cpu_addr, size_t size)
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{
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struct vm_struct *area = find_vm_area(cpu_addr);
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if (!area || !(area->flags & VM_DMA_COHERENT)) {
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WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
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return;
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}
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vunmap(cpu_addr);
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}
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