linux/drivers/tty/n_null.c
Jiri Slaby f81ee8b8b8 tty: make tty_ldisc_ops a param in tty_unregister_ldisc
Make tty_unregister_ldisc symmetric to tty_register_ldisc by accepting
struct tty_ldisc_ops as a parameter instead of ldisc number. This avoids
checking of the ldisc number bounds in tty_unregister_ldisc.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: William Hubbs <w.d.hubbs@gmail.com>
Cc: Chris Brannon <chris@the-brannons.com>
Cc: Kirk Reiser <kirk@reisers.ca>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Andreas Koensgen <ajk@comnets.uni-bremen.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rodolfo Giometti <giometti@enneenne.com>
Cc: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Link: https://lore.kernel.org/r/20210505091928.22010-17-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-13 16:57:16 +02:00

70 lines
1.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/module.h>
/*
* n_null.c - Null line discipline used in the failure path
*
* Copyright (C) Intel 2017
*/
static int n_null_open(struct tty_struct *tty)
{
return 0;
}
static void n_null_close(struct tty_struct *tty)
{
}
static ssize_t n_null_read(struct tty_struct *tty, struct file *file,
unsigned char *buf, size_t nr,
void **cookie, unsigned long offset)
{
return -EOPNOTSUPP;
}
static ssize_t n_null_write(struct tty_struct *tty, struct file *file,
const unsigned char *buf, size_t nr)
{
return -EOPNOTSUPP;
}
static void n_null_receivebuf(struct tty_struct *tty,
const unsigned char *cp, const char *fp,
int cnt)
{
}
static struct tty_ldisc_ops null_ldisc = {
.owner = THIS_MODULE,
.num = N_NULL,
.name = "n_null",
.open = n_null_open,
.close = n_null_close,
.read = n_null_read,
.write = n_null_write,
.receive_buf = n_null_receivebuf
};
static int __init n_null_init(void)
{
BUG_ON(tty_register_ldisc(&null_ldisc));
return 0;
}
static void __exit n_null_exit(void)
{
tty_unregister_ldisc(&null_ldisc);
}
module_init(n_null_init);
module_exit(n_null_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alan Cox");
MODULE_ALIAS_LDISC(N_NULL);
MODULE_DESCRIPTION("Null ldisc driver");