diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 836947da5b14de4f7e75859d2e500cb2001b31a4..7cc5a4a910a43fa48adc032ae44aae09c1ff73af 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -372,7 +372,7 @@ struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev,
 		if (cmd->use_sg) {
 			qc->__sg = (struct scatterlist *) cmd->request_buffer;
 			qc->n_elem = cmd->use_sg;
-		} else {
+		} else if (cmd->request_bufflen) {
 			qc->__sg = &qc->sgent;
 			qc->n_elem = 1;
 		}
diff --git a/include/linux/libata.h b/include/linux/libata.h
index e53a13ba7f7833275b54005a237153ac541ee288..65d318746ac61321f38bbb883da319bef54ad090 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1149,6 +1149,7 @@ static inline void ata_qc_reinit(struct ata_queued_cmd *qc)
 	qc->cursect = qc->cursg = qc->cursg_ofs = 0;
 	qc->nsect = 0;
 	qc->nbytes = qc->curbytes = 0;
+	qc->n_elem = 0;
 	qc->err_mask = 0;
 
 	ata_tf_init(qc->dev, &qc->tf);