Messages in this thread Patch in this message | | | From | Ricardo Ribalda Delgado <> | Subject | [PATCH 2/2] include/dma-mapping: Clarify output of dma_map_sg | Date | Wed, 11 Feb 2015 13:53:15 +0100 |
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Although dma_map_sg returns 0 on error and it cannot return a value < 0, the function returns a signed integer.
Most of the time, this function is used with a scatterlist structure. This structure uses an unsigned integer for the number of memory.
A dma developer that has not read in detail DMA-API.txt, can wrongly return a value < 0 on error.
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> --- include/linux/dma-mapping.h | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index c3007cb..ac07ff0 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -34,6 +34,10 @@ struct dma_map_ops { void (*unmap_page)(struct device *dev, dma_addr_t dma_handle, size_t size, enum dma_data_direction dir, struct dma_attrs *attrs); + /* + * map_sg returns 0 on error and a value > 0 on success. + * It should never return a value < 0. + */ int (*map_sg)(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, struct dma_attrs *attrs); -- 2.1.4
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