[20/34] dma-mapping: warn when there is no coherent_dma_mask

Commit Message

Christoph Hellwig Jan. 12, 2018, 8:42 a.m. UTC

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 <[e-mail]>
Reviewed-by: Vladimir Murzin <[e-mail]>
---
 include/linux/dma-mapping.h | 1 +
 1 file changed, 1 insertion(+)

Patch

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;