Commit dd65a941 authored by Marek Szyprowski's avatar Marek Szyprowski Committed by Catalin Marinas

arm64: dma-mapping: clear buffers allocated with FORCE_CONTIGUOUS flag

dma_alloc_*() buffers might be exposed to userspace via mmap() call, so
they should be cleared on allocation. In case of IOMMU-based dma-mapping
implementation such buffer clearing was missing in the code path for
DMA_ATTR_FORCE_CONTIGUOUS flag handling, because dma_alloc_from_contiguous()
doesn't honor __GFP_ZERO flag. This patch fixes this issue. For more
information on clearing buffers allocated by dma_alloc_* functions,
see commit 6829e274 ("arm64: dma-mapping: always clear allocated

Fixes: 44176bb3 ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU")
Signed-off-by: default avatarMarek Szyprowski <>
Signed-off-by: default avatarCatalin Marinas <>
parent ce397d21
......@@ -583,13 +583,14 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size,
size >> PAGE_SHIFT);
return NULL;
if (!coherent)
__dma_flush_area(page_to_virt(page), iosize);
addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
if (!addr) {
if (addr) {
memset(addr, 0, size);
if (!coherent)
__dma_flush_area(page_to_virt(page), iosize);
} else {
iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs);
dma_release_from_contiguous(dev, page,
size >> PAGE_SHIFT);
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment