structscatterlist{structpage*page;/* Location for highmem page, if any */unsignedintoffset;/* for highmem, page offset */dma_addr_tdma_address;unsignedintlength;};#define ISA_DMA_THRESHOLD (0x1fffffff)
/* These macros should be used after a pci_map_sg call has been done * to get bus addresses of each of the SG entries and their lengths. * You should only work with the number of sg entries pci_map_sg * returns, or alternatively stop on the first sg_dma_len(sg) which * is 0. */#define sg_dma_address(sg) ((sg)->dma_address)#define sg_dma_len(sg) ((sg)->length)