These days all devices should have a DMA coherent mask, and most dma_ops implementations rely on that fact. But just to be sure add an assert to ring the warning bell if that is not the case. Signed-off-by: Christoph Hellwig <hch@xxxxxx> --- include/linux/dma-mapping.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index d84951865be7..9f28b2fa329e 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -513,6 +513,7 @@ static inline void *dma_alloc_attrs(struct device *dev, size_t size, void *cpu_addr; BUG_ON(!ops); + WARN_ON_ONCE(!dev->coherent_dma_mask); if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr)) return cpu_addr; -- 2.14.2