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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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
This commit is contained in:
Christoph Hellwig 2018-09-22 20:47:26 +02:00
parent b18814e767
commit 704f2c20ea
1 changed files with 12 additions and 0 deletions
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12
kernel/dma/direct.c
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@ -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));