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: a4a4330 ("swiotlb: add support for non-coherent DMA") Tested-by: John Stultz <[email protected]> Signed-off-by: Robin Murphy <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]>
torvalds · Nov 21, 2018 · cb216b8 · cb216b8
1 parent b340871
commit cb216b8
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
@@ -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;