[PATCH 08/19] tty: Reset c_line from driver's init_termios

From	Peter Hurley <peter@hurleysoftware.com>
Newsgroups	linux.kernel
Subject	[PATCH 08/19] tty: Reset c_line from driver's init_termios
Date	2015-11-27 22:50 +0100
Message-ID	<qzz3Y-8gp-19@gated-at.bofh.it> (permalink)
References	<qzyUh-8cQ-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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After the ldisc is released, but before the tty is destroyed, the termios
is saved (in tty_free_termios()); this termios is restored if a new
tty is created on next open(). However, the line discipline is always
reset, which is not obvious in the current method. Instead, reset
as part of the restore.

Restore the original line discipline, which may not have been N_TTY.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
---
 drivers/tty/tty_io.c    | 5 +++--
 drivers/tty/tty_ldisc.c | 3 ---
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 56d3a6b..0871d1e 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1388,9 +1388,10 @@ int tty_init_termios(struct tty_struct *tty)
 	else {
 		/* Check for lazy saved data */
 		tp = tty->driver->termios[idx];
-		if (tp != NULL)
+		if (tp != NULL) {
 			tty->termios = *tp;
-		else
+			tty->termios.c_line  = tty->driver->init_termios.c_line;
+		} else
 			tty->termios = tty->driver->init_termios;
 	}
 	/* Compatibility until drivers always set this */
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index c97f8e9..a9b2fd7 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -765,9 +765,6 @@ static void tty_ldisc_kill(struct tty_struct *tty)
 	tty_ldisc_put(tty->ldisc);
 	/* Force an oops if we mess this up */
 	tty->ldisc = NULL;
-
-	/* Ensure the next open requests the N_TTY ldisc */
-	tty_set_termios_ldisc(tty, N_TTY);
 }
 
 /**
-- 
2.6.3

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Thread

[PATCH 00/19] Fix driver crashes on hangup Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:40 +0100
  [PATCH 03/19] bluetooth: hci_ldisc: Remove dead code Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:40 +0100
  [PATCH 06/19] tty: Fix unsafe ldisc reference via ioctl(TIOCGETD) Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 12/19] tty: Prepare for destroying line discipline on hangup Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 19/19] tty: Touch up style issues in ldisc core Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 13/19] tty: Handle NULL tty->ldisc Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 09/19] staging/speakup: Use tty_ldisc_ref() for paste kworker Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 10/19] tty: Fix comments for tty_ldisc_get() Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 14/19] tty: Move tty_ldisc_kill() Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 11/19] tty: Fix comments for tty_ldisc_release() Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 08/19] tty: Reset c_line from driver's init_termios Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 02/19] serial: 68328: Remove bogus ldisc reset Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 17/19] tty: Destroy ldisc instance on hangup Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 01/19] staging: digi: Replace open-coded tty_wakeup() Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 15/19] tty: Use 'disc' for line discipline index name Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 18/19] tty: Document c_line == N_TTY initial condition Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 05/19] tty: Remove chars_in_buffer() line discipline method Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 16/19] tty: Refactor tty_ldisc_reinit() for reuse Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100
  [PATCH 07/19] n_tty: Fix unsafe reference to "other" ldisc Peter Hurley <peter@hurleysoftware.com> - 2015-11-27 22:50 +0100

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