Commit cb216b84 authored Nov 21, 2018 by Robin Murphy Committed by Christoph Hellwig Nov 21, 2018

swiotlb: Skip cache maintenance on map error



If swiotlb_bounce_page() failed, calling arch_sync_dma_for_device() may
lead to such delights as performing cache maintenance on whatever
address phys_to_virt(SWIOTLB_MAP_ERROR) looks like, which is typically
outside the kernel memory map and goes about as well as expected.

Don't do that.

Fixes: a4a4330d ("swiotlb: add support for non-coherent DMA")
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

parent b3408715

kernel/dma/swiotlb.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -679,7 +679,8 @@ dma_addr_t swiotlb_map_page(struct device dev, struct page page,
		}

		if (!dev_is_dma_coherent(dev) &&
		(attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
		(attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0 &&
		dev_addr != DIRECT_MAPPING_ERROR)
		arch_sync_dma_for_device(dev, phys, size, dir);

		return dev_addr;

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