[S390] cio: fix sanity checks in device_ops.

Some sanity checks in device_ops.c test the output of container_of
macros to be !NULL. Test the input parameters instead.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/device_ops.c

@@ -114,7 +114,7 @@ int ccw_device_clear(struct ccw_device *cdev, unsigned long intparm)
 	struct subchannel *sch;
 	int ret;
 
-	if (!cdev)
+	if (!cdev || !cdev->dev.parent)
 		return -ENODEV;
 	if (cdev->private->state == DEV_STATE_NOT_OPER)
 		return -ENODEV;
@@ -122,8 +122,6 @@ int ccw_device_clear(struct ccw_device *cdev, unsigned long intparm)
 	    cdev->private->state != DEV_STATE_W4SENSE)
 		return -EINVAL;
 	sch = to_subchannel(cdev->dev.parent);
-	if (!sch)
-		return -ENODEV;
 	ret = cio_clear(sch);
 	if (ret == 0)
 		cdev->private->intparm = intparm;
@@ -161,11 +159,9 @@ int ccw_device_start_key(struct ccw_device *cdev, struct ccw1 *cpa,
 	struct subchannel *sch;
 	int ret;
 
-	if (!cdev)
+	if (!cdev || !cdev->dev.parent)
 		return -ENODEV;
 	sch = to_subchannel(cdev->dev.parent);
-	if (!sch)
-		return -ENODEV;
 	if (cdev->private->state == DEV_STATE_NOT_OPER)
 		return -ENODEV;
 	if (cdev->private->state == DEV_STATE_VERIFY ||
@@ -339,7 +335,7 @@ int ccw_device_halt(struct ccw_device *cdev, unsigned long intparm)
 	struct subchannel *sch;
 	int ret;
 
-	if (!cdev)
+	if (!cdev || !cdev->dev.parent)
 		return -ENODEV;
 	if (cdev->private->state == DEV_STATE_NOT_OPER)
 		return -ENODEV;
@@ -347,8 +343,6 @@ int ccw_device_halt(struct ccw_device *cdev, unsigned long intparm)
 	    cdev->private->state != DEV_STATE_W4SENSE)
 		return -EINVAL;
 	sch = to_subchannel(cdev->dev.parent);
-	if (!sch)
-		return -ENODEV;
 	ret = cio_halt(sch);
 	if (ret == 0)
 		cdev->private->intparm = intparm;
@@ -372,11 +366,9 @@ int ccw_device_resume(struct ccw_device *cdev)
 {
 	struct subchannel *sch;
 
-	if (!cdev)
+	if (!cdev || !cdev->dev.parent)
 		return -ENODEV;
 	sch = to_subchannel(cdev->dev.parent);
-	if (!sch)
-		return -ENODEV;
 	if (cdev->private->state == DEV_STATE_NOT_OPER)
 		return -ENODEV;
 	if (cdev->private->state != DEV_STATE_ONLINE ||
@@ -471,10 +463,10 @@ __u8 ccw_device_get_path_mask(struct ccw_device *cdev)
 {
 	struct subchannel *sch;
 
-	sch = to_subchannel(cdev->dev.parent);
-	if (!sch)
+	if (!cdev->dev.parent)
 		return 0;
-	else
+
+	sch = to_subchannel(cdev->dev.parent);
 	return sch->lpm;
 }