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>

4 files changed, 7 insertions, 11 deletions

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index cce2ef04caeb..db7d4a30af91 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -3280,13 +3280,13 @@ static int __init gsm_init(void)
 err_put_driver:
 	put_tty_driver(gsm_tty_driver);
 err_unreg_ldisc:
-	tty_unregister_ldisc(N_GSM0710);
+	tty_unregister_ldisc(&tty_ldisc_packet);
 	return status;
 }
 
 static void __exit gsm_exit(void)
 {
-	int status = tty_unregister_ldisc(N_GSM0710);
+	int status = tty_unregister_ldisc(&tty_ldisc_packet);
 	if (status != 0)
 		pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
 								status);
diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
index 2256039911f5..c2afbfe0a1d5 100644
--- a/drivers/tty/n_hdlc.c
+++ b/drivers/tty/n_hdlc.c
@@ -822,8 +822,7 @@ static int __init n_hdlc_init(void)
 
 static void __exit n_hdlc_exit(void)
 {
-	/* Release tty registration of line discipline */
-	int status = tty_unregister_ldisc(N_HDLC);
+	int status = tty_unregister_ldisc(&n_hdlc_ldisc);
 
 	if (status)
 		pr_err("N_HDLC: can't unregister line discipline (err = %d)\n",
diff --git a/drivers/tty/n_null.c b/drivers/tty/n_null.c
index ee229c812dce..f913b665af72 100644
--- a/drivers/tty/n_null.c
+++ b/drivers/tty/n_null.c
@@ -57,7 +57,7 @@ static int __init n_null_init(void)
 
 static void __exit n_null_exit(void)
 {
-	tty_unregister_ldisc(N_NULL);
+	tty_unregister_ldisc(&null_ldisc);
 }
 
 module_init(n_null_init);
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 9aff04bee4cd..d02deeb5e584 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -87,19 +87,16 @@ EXPORT_SYMBOL(tty_register_ldisc);
  *		takes tty_ldiscs_lock to guard against ldisc races
  */
 
-int tty_unregister_ldisc(int disc)
+int tty_unregister_ldisc(struct tty_ldisc_ops *ldisc)
 {
 	unsigned long flags;
 	int ret = 0;
 
-	if (disc < N_TTY || disc >= NR_LDISCS)
-		return -EINVAL;
-
 	raw_spin_lock_irqsave(&tty_ldiscs_lock, flags);
-	if (tty_ldiscs[disc]->refcount)
+	if (tty_ldiscs[ldisc->num]->refcount)
 		ret = -EBUSY;
 	else
-		tty_ldiscs[disc] = NULL;
+		tty_ldiscs[ldisc->num] = NULL;
 	raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags);
 
 	return ret;