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.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 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``
 
 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``
 
 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``
 
 
 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,
 
 
 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,
 
 }
 
 static struct tty_ldisc_ops st_ldisc_ops = {
-       .magic = TTY_LDISC_MAGIC,
        .name = "n_st",
        .open = st_tty_open,
        .close = st_tty_close,
 
 /* 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,
 
 
 static struct tty_ldisc_ops slc_ldisc = {
        .owner          = THIS_MODULE,
-       .magic          = TTY_LDISC_MAGIC,
        .name           = "slcan",
        .open           = slcan_open,
        .close          = slcan_close,
 
 
 static struct tty_ldisc_ops sp_ldisc = {
        .owner          = THIS_MODULE,
-       .magic          = TTY_LDISC_MAGIC,
        .name           = "6pack",
        .open           = sixpack_open,
        .close          = sixpack_close,
 
 
 static struct tty_ldisc_ops ax_ldisc = {
        .owner          = THIS_MODULE,
-       .magic          = TTY_LDISC_MAGIC,
        .name           = "mkiss",
        .open           = mkiss_open,
        .close          = mkiss_close,
 
 
 static struct tty_ldisc_ops ppp_ldisc = {
        .owner  = THIS_MODULE,
-       .magic  = TTY_LDISC_MAGIC,
        .name   = "ppp",
        .open   = ppp_asynctty_open,
        .close  = ppp_asynctty_close,
 
 
 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,
 
 
 static struct tty_ldisc_ops sl_ldisc = {
        .owner          = THIS_MODULE,
-       .magic          = TTY_LDISC_MAGIC,
        .name           = "slip",
        .open           = slip_open,
        .close          = slip_close,
 
 #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;
 
        /* 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;
 
 /* 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,
 
 
 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,
 
 
 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,
 
 
 static struct tty_ldisc_ops tty_ldisc_N_R3964 = {
        .owner = THIS_MODULE,
-       .magic = TTY_LDISC_MAGIC,
        .name = "R3964",
        .open = r3964_open,
        .close = r3964_close,
 
 }
 
 static struct tty_ldisc_ops n_tty_ops = {
-       .magic           = TTY_LDISC_MAGIC,
        .name            = "n_tty",
        .open            = n_tty_open,
        .close           = n_tty_close,
 
 
 
 struct tty_ldisc_ops {
-       int     magic;
        char    *name;
        int     num;
        int     flags;
        struct tty_struct *tty;
 };
 
-#define TTY_LDISC_MAGIC        0x5403
-
 #define LDISC_FLAG_DEFINED     0x00000001
 
 #define MODULE_ALIAS_LDISC(ldisc) \
 
 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,
 
 }
 
 struct tty_ldisc_ops v253_ops = {
-       .magic = TTY_LDISC_MAGIC,
        .name = "cx20442",
        .owner = THIS_MODULE,
        .open = v253_open,
 
 }
 
 static struct tty_ldisc_ops cx81801_ops = {
-       .magic = TTY_LDISC_MAGIC,
        .name = "cx81801",
        .owner = THIS_MODULE,
        .open = cx81801_open,