In case of DMA_ATTR_FORCE_CONTIGUOUS allocations vm_area->pages
is invalid. __iommu_mmap_attrs and __iommu_get_sgtable cannot use
it. In first case temporary pages array is passed to iommu_dma_mmap,
in 2nd case single entry sg table is created directly instead
of calling helper.
Fixes: 44176bb ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU")
Signed-off-by: Andrzej Hajda <[email protected]>
---
Hi,
I am not familiar with this framework so please don't be too cruel ;)
Alternative solution I see is to always create vm_area->pages,
I do not know which approach is preferred.
Regards
Andrzej
---
arch/arm64/mm/dma-mapping.c | 40 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 38 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index f7b5401..bba2bc8 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -704,7 +704,30 @@ static int __iommu_mmap_attrs(struct device *dev, struct
vm_area_struct *vma,
return ret;
area = find_vm_area(cpu_addr);
- if (WARN_ON(!area || !area->pages))
+ if (WARN_ON(!area))
+ return -ENXIO;
+
+ if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+ struct page *page = vmalloc_to_page(cpu_addr);
+ unsigned int count = size >> PAGE_SHIFT;
+ struct page **pages;
+ unsigned long pfn;
+ int i;
+
+ pages = kmalloc_array(count, sizeof(*pages), GFP_KERNEL);
+ if (!pages)
+ return -ENOMEM;
+
+ for (i = 0, pfn = page_to_pfn(page); i < count; i++)
+ pages[i] = pfn_to_page(pfn + i);
+
+ ret = iommu_dma_mmap(pages, size, vma);
+ kfree(pages);
+
+ return ret;
+ }
+
+ if (WARN_ON(!area->pages))
return -ENXIO;
return iommu_dma_mmap(area->pages, size, vma);
@@ -717,7 +740,20 @@ 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 (WARN_ON(!area || !area->pages))
+ if (WARN_ON(!area))
+ return -ENXIO;
+
+ 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;
+ }
+
+ if (WARN_ON(!area->pages))
return -ENXIO;
return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size,
--
2.7.4
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