In case of DMA_ATTR_FORCE_CONTIGUOUS allocations vm_area->pages
is invalid. __iommu_mmap_attrs and __iommu_get_sgtable should not
use it and take advantage of contiguous nature of the allocation.
Fixes: 44176bb ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU")
Signed-off-by: Andrzej Hajda <[email protected]>
---
Hi Robin, Geert,
In this version of the patch I have replaced temporal pages and
iommu_dma_mmap with remap_pfn_range or rather its simplified version
vm_iomap_memory.
Unfortunately I have not find nice helper for sgtable creation, so I
left sg allocation inside _iommu_mmap_attrs.
As the fixing of DMA_ATTR_FORCE_CONTIGUOUS related crashes has higher
priority I have focused only on it in this patch.
Regards
Andrzej
---
arch/arm64/mm/dma-mapping.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index f7b5401..41c7c36 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -703,6 +703,10 @@ static int __iommu_mmap_attrs(struct device *dev, struct
vm_area_struct *vma,
if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
return ret;
+ if (attrs & DMA_ATTR_FORCE_CONTIGUOUS)
+ return vm_iomap_memory(vma,
+ page_to_phys(vmalloc_to_page(cpu_addr)), size);
+
area = find_vm_area(cpu_addr);
if (WARN_ON(!area || !area->pages))
return -ENXIO;
@@ -715,8 +719,19 @@ static int __iommu_get_sgtable(struct device *dev, struct
sg_table *sgt,
size_t size, unsigned long attrs)
{
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
- struct vm_struct *area = find_vm_area(cpu_addr);
+ struct vm_struct *area;
+
+ if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+ int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+
+ if (!ret)
+ sg_set_page(sgt->sgl, vmalloc_to_page(cpu_addr),
+ PAGE_ALIGN(size), 0);
+ return ret;
+ }
+
+ area = find_vm_area(cpu_addr);
if (WARN_ON(!area || !area->pages))
return -ENXIO;
--
2.7.4
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