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    Subject[PATCH 01/21] arm64/iommu: handle non-remapped addresses in ->mmap and ->get_sgtable
    Date
    DMA allocations that can't sleep may return non-remapped addresses, but
    we do not properly handle them in the mmap and get_sgtable methods.
    Resolve non-vmalloc addresses using virt_to_page to handle this corner
    case.

    Signed-off-by: Christoph Hellwig <hch@lst.de>
    ---
    arch/arm64/mm/dma-mapping.c | 12 +++++++++++-
    1 file changed, 11 insertions(+), 1 deletion(-)

    diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
    index 78c0a72f822c..be88beb2e377 100644
    --- a/arch/arm64/mm/dma-mapping.c
    +++ b/arch/arm64/mm/dma-mapping.c
    @@ -249,6 +249,11 @@ static int __iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
    if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
    return ret;

    + if (!is_vmalloc_addr(cpu_addr)) {
    + unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
    + return __swiotlb_mmap_pfn(vma, pfn, size);
    + }
    +
    if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
    /*
    * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
    @@ -272,10 +277,15 @@ static int __iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
    unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
    struct vm_struct *area = find_vm_area(cpu_addr);

    + if (!is_vmalloc_addr(cpu_addr)) {
    + struct page *page = virt_to_page(cpu_addr);
    + return __swiotlb_get_sgtable_page(sgt, page, size);
    + }
    +
    if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
    /*
    * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
    - * hence in the vmalloc space.
    + * hence in the vmalloc space.
    */
    struct page *page = vmalloc_to_page(cpu_addr);
    return __swiotlb_get_sgtable_page(sgt, page, size);
    --
    2.20.1
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