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dma-mapping: Convert NO_DMA get_dma_ops() into a real dummy

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If NO_DMA=y, get_dma_ops() returns a reference to the
non-existing symbol bad_dma_ops, thus causing a link failure if it is
ever used.

Make get_dma_ops() return NULL instead, to avoid the link failure.
This allows to improve compile-testing, and limits the need to keep on
sprinkling dependencies on HAS_DMA all over the place.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Geert Uytterhoeven 2018-03-16 14:25:40 +01:00 committed by Christoph Hellwig
parent 0c8efd610b
commit f29ab49b53
1 changed files with 5 additions and 5 deletions
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10
include/linux/dma-mapping.h
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@ -212,14 +212,14 @@ static inline void set_dma_ops(struct device *dev,
}
#else
/*
* Define the dma api to allow compilation but not linking of
* dma dependent code. Code that depends on the dma-mapping
* API needs to set 'depends on HAS_DMA' in its Kconfig
* Define the dma api to allow compilation of dma dependent code.
* Code that depends on the dma-mapping API needs to set 'depends on HAS_DMA'
* in its Kconfig, unless it already depends on <something> || COMPILE_TEST,
* where <something> guarantuees the availability of the dma-mapping API.
*/
extern const struct dma_map_ops bad_dma_ops;
static inline const struct dma_map_ops *get_dma_ops(struct device *dev)
{
return &bad_dma_ops;
return NULL;
}
#endif