Messages in this thread Patch in this message | | | From | Geert Uytterhoeven <> | Subject | [PATCH v2 1/5] dma-mapping: Convert NO_DMA get_dma_ops() into a real dummy | Date | Fri, 16 Mar 2018 14:25:40 +0100 |
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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> --- v2: - Add Reviewed-by, Acked-by, - Drop RFC state. --- include/linux/dma-mapping.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index eb9eab4ecd6d7a05..5ea7eec83c0fbb82 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -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 -- 2.7.4
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