Although dma_map_sg_attrs 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. The comment will help the driver developer, and the WARN_ON the dma developer. Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx> --- include/asm-generic/dma-mapping-common.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/asm-generic/dma-mapping-common.h b/include/asm-generic/dma-mapping-common.h index 3378dcf..940d5ec 100644 --- a/include/asm-generic/dma-mapping-common.h +++ b/include/asm-generic/dma-mapping-common.h @@ -39,6 +39,10 @@ static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr, debug_dma_unmap_page(dev, addr, size, dir, true); } +/* + * dma_maps_sg_attrs returns 0 on error and > 0 on success. + * It should never return a value < 0. + */ static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, struct dma_attrs *attrs) @@ -51,6 +55,7 @@ static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, kmemcheck_mark_initialized(sg_virt(s), s->length); BUG_ON(!valid_dma_direction(dir)); ents = ops->map_sg(dev, sg, nents, dir, attrs); + BUG_ON(ents < 0); debug_dma_map_sg(dev, sg, nents, ents, dir); return ents; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
