tty: n_null: remove optional ldops

Only tty_ldisc_ops::read() and ::write() of n_null behave differently than
the default ldops implementations. They return %EOPNOTSUPP instead of
%EIO. So keep only those two and remove the rest ldops as they are
superfluous.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230810091510.13006-5-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/n_null.c b/drivers/tty/n_null.c
index f913b665af725d699b2a9d7ad8cd335905e6ecf1..4a0d8bb2fb4c2ea5a807549862866f5a9313102f 100644 (file)
--- a/drivers/tty/n_null.c
+++ b/drivers/tty/n_null.c
@@ -10,15 +10,6 @@
  *  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)
@@ -32,21 +23,12 @@ static ssize_t n_null_write(struct tty_struct *tty, struct file *file,
        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)