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>
This commit is contained in:
Peter Hurley
2016-01-10 22:40:54 -08:00
committed by Greg Kroah-Hartman
parent 582e20a03b
commit fdfb719e93
8 changed files with 13 additions and 68 deletions

View File

@@ -965,8 +965,7 @@ static void rs_throttle(struct tty_struct * tty)
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 @@ static void rs_unthrottle(struct tty_struct * tty)
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"))