Some DMA regions, for example those created by dma_declare_coherent_memory,
might not be possible to be represented by struct page pointers. Getting
scatterlist for the buffer allocated from such region is not possible.
This patch adds a simple check in arm_dma_get_sgtable() function if the
exported struct page pointer is valid.
Fixes: dc2832e1e7db3 ("ARM: dma-mapping: add support for dma_get_sgtable()")
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
arch/arm/mm/dma-mapping.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index fc4a4eaa9934..4b2cf82fbca6 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -942,6 +942,10 @@ int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
struct page *page = pfn_to_page(dma_to_pfn(dev, handle));
int ret;
+ /* Check if DMA handle has been properly translated to page. */
+ if (pfn_to_dma(dev, page_to_pfn(page)) != handle)
+ return -ENXIO;
+
ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
if (unlikely(ret))
return ret;
--
1.9.1