diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 011c0a8a2dcc..0d51d13b16bf 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1332,7 +1332,7 @@ unsigned ata_exec_internal_sg(struct ata_device *dev,
 }
 
 /**
- *	ata_exec_internal_sg - execute libata internal command
+ *	ata_exec_internal - execute libata internal command
  *	@dev: Device to which the command is sent
  *	@tf: Taskfile registers for the command and the result
  *	@cdb: CDB for packet command
@@ -1353,11 +1353,17 @@ unsigned ata_exec_internal(struct ata_device *dev,
 			   struct ata_taskfile *tf, const u8 *cdb,
 			   int dma_dir, void *buf, unsigned int buflen)
 {
-	struct scatterlist sg;
+	struct scatterlist *psg = NULL, sg;
+	unsigned int n_elem = 0;
 
-	sg_init_one(&sg, buf, buflen);
+	if (dma_dir != DMA_NONE) {
+		WARN_ON(!buf);
+		sg_init_one(&sg, buf, buflen);
+		psg = &sg;
+		n_elem++;
+	}
 
-	return ata_exec_internal_sg(dev, tf, cdb, dma_dir, &sg, 1);
+	return ata_exec_internal_sg(dev, tf, cdb, dma_dir, psg, n_elem);
 }
 
 /**