[PATCH] sata: fix sata_sx4 dma_prep to not use sg->length

 sata_sx4 directly references sg->length to calculate total_len in
pdc20621_dma_prep().  This is incorrect as dma_map_sg() could have
merged multiple sg's into one and, in such case, sg->length doesn't
reflect true size of the entry.  This patch makes it use
sg_dma_len(sg).
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>

drivers/scsi/sata_sx4.c

@@ -468,7 +468,7 @@ static void pdc20621_dma_prep(struct ata_queued_cmd *qc)
 	for (i = 0; i < last; i++) {
 		buf[idx++] = cpu_to_le32(sg_dma_address(&sg[i]));
 		buf[idx++] = cpu_to_le32(sg_dma_len(&sg[i]));
-		total_len += sg[i].length;
+		total_len += sg_dma_len(&sg[i]);
 	}
 	buf[idx - 1] |= cpu_to_le32(ATA_PRD_EOT);
 	sgt_len = idx * 4;