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Commit 704f2c20 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-direct: reject highmem pages from dma_alloc_from_contiguous 



dma_alloc_from_contiguous can return highmem pages depending on the
setup, which a plain non-remapping DMA allocator can't handle.  Detect
this case and fail the allocation.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarRobin Murphy <robin.murphy@arm.com>
parent b18814e7

kernel/dma/direct.c

+12 −0
Original line number Diff line number Diff line
@@ -162,6 +162,18 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, 
	if (!page)

		return NULL;



	if (PageHighMem(page)) {

		/*

		 * Depending on the cma= arguments and per-arch setup

		 * dma_alloc_from_contiguous could return highmem pages.

		 * Without remapping there is no way to return them here,

		 * so log an error and fail.

		 */

		dev_info(dev, "Rejecting highmem page from CMA.\n");

		__dma_direct_free_pages(dev, size, page);

		return NULL;

	}



	ret = page_address(page);

	if (force_dma_unencrypted()) {

		set_memory_decrypted((unsigned long)ret, 1 << get_order(size));