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Commit e2275bf3 authored by Neeti Desai's avatar Neeti Desai Committed by Patrick Daly
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arm64: dma-mapping: Split large pages when allocating in atomic context 



In atomic context, gen_pool_alloc allocates a single page large
enough to accommodate the requested size. However __iommu_create_mapping
always maps pages assuming they are of size 4K. Thus only the first
4K of the buffer is mapped and a translation fault is generated
during an unmap.

Fix this by splitting the larger pages into 4K pages.

Change-Id: Ifcbe29477ad210204028486bd011470fe8b50852
Signed-off-by: default avatarNeeti Desai <neetid@codeaurora.org>
Signed-off-by: default avatarMitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
parent 040a288a

arch/arm64/mm/dma-mapping.c

+20 −2
Original line number Diff line number Diff line
@@ -1366,20 +1366,38 @@ static void *__iommu_alloc_atomic(struct device *dev, size_t size, 
				  dma_addr_t *handle, gfp_t gfp)

{

	struct page *page;

	struct page **pages;

	int count = size >> PAGE_SHIFT;

	int array_size = count * sizeof(struct page *);

	int i;

	void *addr;



	if (array_size <= PAGE_SIZE)

		pages = kzalloc(array_size, gfp);

	else

		pages = vzalloc(array_size);



	if (!pages)

		return NULL;



	addr = __alloc_from_pool(size, &page, gfp);

	if (!addr)

		return NULL;

		goto err_free;



	*handle = __iommu_create_mapping(dev, &page, size);

	for (i = 0; i < count ; i++)

		pages[i] = page + i;



	*handle = __iommu_create_mapping(dev, pages, size);

	if (*handle == DMA_ERROR_CODE)

		goto err_mapping;



	kvfree(pages);

	return addr;



err_mapping:

	__free_from_pool(addr, size);

err_free:

	kvfree(pages);

	return NULL;

}