struct scatterlist *sg = qc->sg;
struct scatterlist *sg = qc->__sg;
static int ata_sg_setup_one(struct ata_queued_cmd *qc){	struct ata_port *ap = qc->ap;	int dir = qc->dma_dir;	struct scatterlist *sg = qc->sg;	dma_addr_t dma_address;	dma_address = dma_map_single(ap->host_set->dev, qc->buf_virt,				     sg->length, dir);	if (dma_mapping_error(dma_address))		return -1;	sg_dma_address(sg) = dma_address;	sg_dma_len(sg) = sg->length;	DPRINTK("mapped buffer of %d bytes for %s\n", sg_dma_len(sg),		qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");	return 0;}