diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index c4eb4ae..8e575fb 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1159,6 +1159,7 @@
 {
 	sdev->use_10_for_rw = 1;
 	sdev->use_10_for_ms = 1;
+	sdev->no_write_same = 1;
 
 	/* Schedule policy is determined by ->qc_defer() callback and
 	 * it needs to see every deferred qc.  Set dev_blocked to 1 to
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index efc48bf..823e938 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -4090,7 +4090,20 @@
 
 	/* allocate host */
 	if (pdev->dev.of_node) {
-		of_property_read_u32(pdev->dev.of_node, "nr-ports", &n_ports);
+		rc = of_property_read_u32(pdev->dev.of_node, "nr-ports",
+					   &n_ports);
+		if (rc) {
+			dev_err(&pdev->dev,
+				"error parsing nr-ports property: %d\n", rc);
+			return rc;
+		}
+
+		if (n_ports <= 0) {
+			dev_err(&pdev->dev, "nr-ports must be positive: %d\n",
+				n_ports);
+			return -EINVAL;
+		}
+
 		irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
 	} else {
 		mv_platform_data = dev_get_platdata(&pdev->dev);