caif: check write operations

write is optional for a tty device. Check that we have a write op rather
than calling NULL.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alan Cox 2010-04-07 16:49:31 -07:00 committed by David S. Miller
parent 298b9e44be
commit c93f094021

View file

@ -312,6 +312,10 @@ static int ldisc_open(struct tty_struct *tty)
char name[64];
int result;
/* No write no play */
if (tty->ops->write == NULL)
return -EOPNOTSUPP;
sprintf(name, "cf%s", tty->name);
dev = alloc_netdev(sizeof(*ser), name, caifdev_setup);
ser = netdev_priv(dev);