[patch] netiucv: silence an underflow warning

[Dan Carpenter]

I haven't looked at the implications but we accidentally allow bs1 to
be negative.  It makes my static checker complain.

Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

diff --git a/drivers/s390/net/netiucv.c b/drivers/s390/net/netiucv.c
index b0e8ffd..85a5744 100644
--- a/drivers/s390/net/netiucv.c
+++ b/drivers/s390/net/netiucv.c
@@ -1578,7 +1578,7 @@ static ssize_t buffer_write (struct device *dev, struct device_attribute *attr,
 			*e);
 		return -EINVAL;
 	}
-	if (bs1 > NETIUCV_BUFSIZE_MAX) {
+	if (bs1 < 0 || bs1 > NETIUCV_BUFSIZE_MAX) {
 		IUCV_DBF_TEXT_(setup, 2,
 			"buffer_write: buffer size %d too large\n",
 			bs1);