[PATCH 19/33] dma-mapping: warn when there is no coherent_dma_mask

Christoph Hellwig
2018-01-10T08:00:13Z

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 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