diff options
Diffstat (limited to 'drivers/net/slip.c')
| -rw-r--r-- | drivers/net/slip.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/net/slip.c b/drivers/net/slip.c index 5a55ede352f4..9d138bf021a6 100644 --- a/drivers/net/slip.c +++ b/drivers/net/slip.c @@ -460,10 +460,14 @@ static void sl_tx_timeout(struct net_device *dev) /* 20 sec timeout not reached */ goto out; } - printk(KERN_WARNING "%s: transmit timed out, %s?\n", - dev->name, - (sl->tty->driver->chars_in_buffer(sl->tty) || sl->xleft) ? - "bad line quality" : "driver error"); + { + int cib = 0; + if (sl->tty->driver->chars_in_buffer) + cib = sl->tty->driver->chars_in_buffer(sl->tty); + printk(KERN_WARNING "%s: transmit timed out, %s?\n", + dev->name, (cib || sl->xleft) ? + "bad line quality" : "driver error"); + } sl->xleft = 0; sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP); sl_unlock(sl); @@ -829,6 +833,8 @@ static int slip_open(struct tty_struct *tty) if (!capable(CAP_NET_ADMIN)) return -EPERM; + if (!tty->driver->write) + return -EOPNOTSUPP; /* RTnetlink lock is misused here to serialize concurrent opens of slip channels. There are better ways, but it is |