> +/*
> + * TTY operations open function.
> + */
> +static int tpk_open(struct tty_struct *tty, struct file *filp)
> +{
> + struct ttyprintk_port *port = &tpk_port;
You can replace the rest with
return tty_port_open(port, tty, filp);
}
> + * TTY operations close function.
> + */
> +static void tpk_close(struct tty_struct *tty, struct file *filp)
> +{
> + struct ttyprintk_port *port = tty->driver_data;
and
tty_port_close(port, tty, filp);
> +}
which saves a lot of work
> +
> +/*
> + * TTY operations write function.
> + */
> +int tpk_write(struct tty_struct *tty,
> + const unsigned char *buf, int count)
> +{
> + struct ttyprintk_port *port;
> + int ret;
> +
> + port = tty->driver_data;
> +
> + if (!port)
> + return 0;
> +
> + if (!(port->port.flags & ASYNC_INITIALIZED))
> + return 0;
These two can't happen if you use tty_port_* so it is better to blow up.
If you think you may be seeing it occur then use WARN_ON() or similar
> +
> + /* exclusive use of tpk_printk within this tty */
> + mutex_lock(&port->port_write_mutex);
> + ret = tpk_printk(buf, count);
> + mutex_unlock(&port->port_write_mutex);
And this is serialized by the caller (not that having your own lock is
any harm)
> +#define TPKRLEV (('e'<<8) | 0) /* Wait for ttyprintk ratelimiting event*/
> +static int tpk_ioctl(struct tty_struct *tty, struct file *file,
> + unsigned int cmd, unsigned long arg)
> +{
> + struct ttyprintk_port *port;
> +
> + port = tty->driver_data;
> +
> + if (!port)
> + return -EINVAL;
> +
> + switch (cmd) {
> + case TPKRLEV:
> + wait_event_interruptible(ttyprintk_ratelimit_wq,
> + (ttyprintk_ratelimit_event != 0));
Ok that wasn't quite what I had in mind.
What I was thinking was needed was this
/* Stop TIOCCONS */
case TIOCCONS:
return -EOPNOTSUPP;
only it won't work that way. I'll sort that out in tty_io.c once the
driver is happy. That way anything trying to mis-redirect the console
will get stopped early which is probably more reliable than a ratelimit ?
> + memset(&tpk_port, 0, sizeof(tpk_port));
It's static so that isn't needed
> + tty_port_init(&tpk_port.port);
> + spin_lock_init(&tpk_port.lock);
The one other bit you will need to use the helpers is
struct tty_port_operations null_ops = { };
tpk_port.port->ops = &null_ops;
Alan
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