tty: Remove chars_in_buffer() line discipline method
The chars_in_buffer() line discipline method serves no functional
purpose, other than as a (dubious) debugging aid for mostly bit-rotting
drivers. Despite being documented as an optional method, every caller
is unconditionally executed (although conditionally compiled).
Furthermore, direct tty->ldisc access without an ldisc ref is unsafe.
Lastly, N_TTY's chars_in_buffer() has warned of removal since 3.12.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c
index 2caaf5a..6ba5681 100644
--- a/drivers/tty/amiserial.c
+++ b/drivers/tty/amiserial.c
@@ -965,8 +965,7 @@
struct serial_state *info = tty->driver_data;
unsigned long flags;
#ifdef SERIAL_DEBUG_THROTTLE
- printk("throttle %s: %d....\n", tty_name(tty),
- tty->ldisc.chars_in_buffer(tty));
+ printk("throttle %s ....\n", tty_name(tty));
#endif
if (serial_paranoia_check(info, tty->name, "rs_throttle"))
@@ -988,8 +987,7 @@
struct serial_state *info = tty->driver_data;
unsigned long flags;
#ifdef SERIAL_DEBUG_THROTTLE
- printk("unthrottle %s: %d....\n", tty_name(tty),
- tty->ldisc.chars_in_buffer(tty));
+ printk("unthrottle %s ....\n", tty_name(tty));
#endif
if (serial_paranoia_check(info, tty->name, "rs_unthrottle"))