[PATCH 21/67] dma-mapping: warn when there is no coherent_dma_mask

[Christoph Hellwig <hch@lst.de>]

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@lst.de>
---
 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 e77e2dec4723..2779d544485c 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -520,6 +520,7 @@ 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