tty: remove TTY_LDISC_MAGIC

First, it is never checked. Second, use of it as a debugging aid is
at least questionable. With the current tools, I don't think anyone used
this kind of thing for debugging purposes for years.

On the top of that, e.g. serdev does not set this field of tty_ldisc_ops
at all.

So get rid of this legacy.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210302062214.29627-8-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/process/magic-number.rst

@@ -88,7 +88,6 @@ TTY_MAGIC             0x5401           tty_struct               ``include/linux/
 MGSL_MAGIC            0x5401           mgsl_info                ``drivers/char/synclink.c``
 TTY_DRIVER_MAGIC      0x5402           tty_driver               ``include/linux/tty_driver.h``
 MGSLPC_MAGIC          0x5402           mgslpc_info              ``drivers/char/pcmcia/synclink_cs.c``
-TTY_LDISC_MAGIC       0x5403           tty_ldisc                ``include/linux/tty_ldisc.h``
 USB_SERIAL_MAGIC      0x6702           usb_serial               ``drivers/usb/serial/usb-serial.h``
 FULL_DUPLEX_MAGIC     0x6969                                    ``drivers/net/ethernet/dec/tulip/de2104x.c``
 USB_BLUETOOTH_MAGIC   0x6d02           usb_bluetooth            ``drivers/usb/class/bluetty.c``

Documentation/translations/it_IT/process/magic-number.rst

@@ -94,7 +94,6 @@ TTY_MAGIC             0x5401           tty_struct               ``include/linux/
 MGSL_MAGIC            0x5401           mgsl_info                ``drivers/char/synclink.c``
 TTY_DRIVER_MAGIC      0x5402           tty_driver               ``include/linux/tty_driver.h``
 MGSLPC_MAGIC          0x5402           mgslpc_info              ``drivers/char/pcmcia/synclink_cs.c``
-TTY_LDISC_MAGIC       0x5403           tty_ldisc                ``include/linux/tty_ldisc.h``
 USB_SERIAL_MAGIC      0x6702           usb_serial               ``drivers/usb/serial/usb-serial.h``
 FULL_DUPLEX_MAGIC     0x6969                                    ``drivers/net/ethernet/dec/tulip/de2104x.c``
 USB_BLUETOOTH_MAGIC   0x6d02           usb_bluetooth            ``drivers/usb/class/bluetty.c``

Documentation/translations/zh_CN/process/magic-number.rst

@@ -77,7 +77,6 @@ TTY_MAGIC             0x5401           tty_struct               ``include/linux/
 MGSL_MAGIC            0x5401           mgsl_info                ``drivers/char/synclink.c``
 TTY_DRIVER_MAGIC      0x5402           tty_driver               ``include/linux/tty_driver.h``
 MGSLPC_MAGIC          0x5402           mgslpc_info              ``drivers/char/pcmcia/synclink_cs.c``
-TTY_LDISC_MAGIC       0x5403           tty_ldisc                ``include/linux/tty_ldisc.h``
 USB_SERIAL_MAGIC      0x6702           usb_serial               ``drivers/usb/serial/usb-serial.h``
 FULL_DUPLEX_MAGIC     0x6969                                    ``drivers/net/ethernet/dec/tulip/de2104x.c``
 USB_BLUETOOTH_MAGIC   0x6d02           usb_bluetooth            ``drivers/usb/class/bluetty.c``

drivers/accessibility/speakup/spk_ttyio.c

@@ -104,7 +104,6 @@ static int spk_ttyio_receive_buf2(struct tty_struct *tty,
 
 static struct tty_ldisc_ops spk_ttyio_ldisc_ops = {
 	.owner          = THIS_MODULE,
-	.magic          = TTY_LDISC_MAGIC,
 	.name           = "speakup_ldisc",
 	.open           = spk_ttyio_ldisc_open,
 	.close          = spk_ttyio_ldisc_close,

drivers/bluetooth/hci_ldisc.c

@@ -821,7 +821,6 @@ static __poll_t hci_uart_tty_poll(struct tty_struct *tty,
 
 static struct tty_ldisc_ops hci_uart_ldisc = {
 	.owner		= THIS_MODULE,
-	.magic		= TTY_LDISC_MAGIC,
 	.name		= "n_hci",
 	.open		= hci_uart_tty_open,
 	.close		= hci_uart_tty_close,

drivers/misc/ti-st/st_core.c

@@ -845,7 +845,6 @@ static void st_tty_flush_buffer(struct tty_struct *tty)
 }
 
 static struct tty_ldisc_ops st_ldisc_ops = {
-	.magic = TTY_LDISC_MAGIC,
 	.name = "n_st",
 	.open = st_tty_open,
 	.close = st_tty_close,

drivers/net/caif/caif_serial.c

@@ -382,7 +382,6 @@ static void ldisc_close(struct tty_struct *tty)
 /* The line discipline structure. */
 static struct tty_ldisc_ops caif_ldisc = {
 	.owner =	THIS_MODULE,
-	.magic =	TTY_LDISC_MAGIC,
 	.name =		"n_caif",
 	.open =		ldisc_open,
 	.close =	ldisc_close,

drivers/net/can/slcan.c

@@ -697,7 +697,6 @@ static int slcan_ioctl(struct tty_struct *tty, struct file *file,
 
 static struct tty_ldisc_ops slc_ldisc = {
 	.owner		= THIS_MODULE,
-	.magic		= TTY_LDISC_MAGIC,
 	.name		= "slcan",
 	.open		= slcan_open,
 	.close		= slcan_close,

drivers/net/hamradio/6pack.c

@@ -749,7 +749,6 @@ static int sixpack_ioctl(struct tty_struct *tty, struct file *file,
 
 static struct tty_ldisc_ops sp_ldisc = {
 	.owner		= THIS_MODULE,
-	.magic		= TTY_LDISC_MAGIC,
 	.name		= "6pack",
 	.open		= sixpack_open,
 	.close		= sixpack_close,

drivers/net/hamradio/mkiss.c

@@ -933,7 +933,6 @@ static void mkiss_write_wakeup(struct tty_struct *tty)
 
 static struct tty_ldisc_ops ax_ldisc = {
 	.owner		= THIS_MODULE,
-	.magic		= TTY_LDISC_MAGIC,
 	.name		= "mkiss",
 	.open		= mkiss_open,
 	.close		= mkiss_close,

drivers/net/ppp/ppp_async.c

@@ -372,7 +372,6 @@ ppp_asynctty_wakeup(struct tty_struct *tty)
 
 static struct tty_ldisc_ops ppp_ldisc = {
 	.owner  = THIS_MODULE,
-	.magic	= TTY_LDISC_MAGIC,
 	.name	= "ppp",
 	.open	= ppp_asynctty_open,
 	.close	= ppp_asynctty_close,

drivers/net/ppp/ppp_synctty.c

@@ -365,7 +365,6 @@ ppp_sync_wakeup(struct tty_struct *tty)
 
 static struct tty_ldisc_ops ppp_sync_ldisc = {
 	.owner	= THIS_MODULE,
-	.magic	= TTY_LDISC_MAGIC,
 	.name	= "pppsync",
 	.open	= ppp_sync_open,
 	.close	= ppp_sync_close,

drivers/net/slip/slip.c

@@ -1263,7 +1263,6 @@ static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 
 static struct tty_ldisc_ops sl_ldisc = {
 	.owner 		= THIS_MODULE,
-	.magic 		= TTY_LDISC_MAGIC,
 	.name 		= "slip",
 	.open 		= slip_open,
 	.close	 	= slip_close,

drivers/pps/clients/pps-ldisc.c

@@ -13,8 +13,6 @@
 #include <linux/pps_kernel.h>
 #include <linux/bug.h>
 
-#define PPS_TTY_MAGIC		0x0001
-
 static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status)
 {
 	struct pps_device *pps;
@@ -114,7 +112,6 @@ static int __init pps_tty_init(void)
 
 	/* Init PPS_TTY data */
 	pps_ldisc_ops.owner = THIS_MODULE;
-	pps_ldisc_ops.magic = PPS_TTY_MAGIC;
 	pps_ldisc_ops.name = "pps_tty";
 	pps_ldisc_ops.dcd_change = pps_tty_dcd_change;
 	pps_ldisc_ops.open = pps_tty_open;

drivers/tty/n_gsm.c

@@ -2849,7 +2849,6 @@ static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
 /* Line discipline for real tty */
 static struct tty_ldisc_ops tty_ldisc_packet = {
 	.owner		 = THIS_MODULE,
-	.magic           = TTY_LDISC_MAGIC,
 	.name            = "n_gsm",
 	.open            = gsmld_open,
 	.close           = gsmld_close,

drivers/tty/n_hdlc.c

@@ -787,7 +787,6 @@ static struct n_hdlc_buf *n_hdlc_buf_get(struct n_hdlc_buf_list *buf_list)
 
 static struct tty_ldisc_ops n_hdlc_ldisc = {
 	.owner		= THIS_MODULE,
-	.magic		= TTY_LDISC_MAGIC,
 	.name		= "hdlc",
 	.open		= n_hdlc_tty_open,
 	.close		= n_hdlc_tty_close,

drivers/tty/n_null.c

@@ -40,7 +40,6 @@ static void n_null_receivebuf(struct tty_struct *tty,
 
 static struct tty_ldisc_ops null_ldisc = {
 	.owner		=	THIS_MODULE,
-	.magic		=	TTY_LDISC_MAGIC,
 	.name		=	"n_null",
 	.open		=	n_null_open,
 	.close		=	n_null_close,

drivers/tty/n_r3964.c

@@ -146,7 +146,6 @@ static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 
 static struct tty_ldisc_ops tty_ldisc_N_R3964 = {
 	.owner = THIS_MODULE,
-	.magic = TTY_LDISC_MAGIC,
 	.name = "R3964",
 	.open = r3964_open,
 	.close = r3964_close,

drivers/tty/n_tty.c

@@ -2488,7 +2488,6 @@ static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
 }
 
 static struct tty_ldisc_ops n_tty_ops = {
-	.magic           = TTY_LDISC_MAGIC,
 	.name            = "n_tty",
 	.open            = n_tty_open,
 	.close           = n_tty_close,

include/linux/tty_ldisc.h

@@ -173,7 +173,6 @@ extern int ldsem_down_write_nested(struct ld_semaphore *sem, int subclass,
 
 
 struct tty_ldisc_ops {
-	int	magic;
 	char	*name;
 	int	num;
 	int	flags;
@@ -218,8 +217,6 @@ struct tty_ldisc {
 	struct tty_struct *tty;
 };
 
-#define TTY_LDISC_MAGIC	0x5403
-
 #define LDISC_FLAG_DEFINED	0x00000001
 
 #define MODULE_ALIAS_LDISC(ldisc) \

net/nfc/nci/uart.c

@@ -453,7 +453,6 @@ void nci_uart_set_config(struct nci_uart *nu, int baudrate, int flow_ctrl)
 EXPORT_SYMBOL_GPL(nci_uart_set_config);
 
 static struct tty_ldisc_ops nci_uart_ldisc = {
-	.magic		= TTY_LDISC_MAGIC,
 	.owner		= THIS_MODULE,
 	.name		= "n_nci",
 	.open		= nci_uart_tty_open,

sound/soc/codecs/cx20442.c

@@ -285,7 +285,6 @@ static void v253_wakeup(struct tty_struct *tty)
 }
 
 struct tty_ldisc_ops v253_ops = {
-	.magic = TTY_LDISC_MAGIC,
 	.name = "cx20442",
 	.owner = THIS_MODULE,
 	.open = v253_open,

sound/soc/ti/ams-delta.c

@@ -395,7 +395,6 @@ static void cx81801_wakeup(struct tty_struct *tty)
 }
 
 static struct tty_ldisc_ops cx81801_ops = {
-	.magic = TTY_LDISC_MAGIC,
 	.name = "cx81801",
 	.owner = THIS_MODULE,
 	.open = cx81801_open,