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>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/tty/cyclades.c b/drivers/tty/cyclades.c
index abbed201dc74..a48e7e66b970 100644
--- a/drivers/tty/cyclades.c
+++ b/drivers/tty/cyclades.c
@@ -2852,8 +2852,8 @@ static void cy_throttle(struct tty_struct *tty)
         unsigned long flags;
 
 #ifdef CY_DEBUG_THROTTLE
-        printk(KERN_DEBUG "cyc:throttle %s: %ld...ttyC%d\n", tty_name(tty),
-                        tty->ldisc.chars_in_buffer(tty), info->line);
+        printk(KERN_DEBUG "cyc:throttle %s ...ttyC%d\n", tty_name(tty),
+                         info->line);
 #endif
 
         if (serial_paranoia_check(info, tty->name, "cy_throttle"))
@@ -2891,8 +2891,8 @@ static void cy_unthrottle(struct tty_struct *tty)
         unsigned long flags;
 
 #ifdef CY_DEBUG_THROTTLE
-        printk(KERN_DEBUG "cyc:unthrottle %s: %ld...ttyC%d\n",
-                tty_name(tty), tty_chars_in_buffer(tty), info->line);
+        printk(KERN_DEBUG "cyc:unthrottle %s ...ttyC%d\n",
+                tty_name(tty), info->line);
 #endif
 
         if (serial_paranoia_check(info, tty->name, "cy_unthrottle"))