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);