linux-kernel - [PATCH v3 08/19] tty: Reset c_line from driver's init

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Date:	Sun, 10 Jan 2016 22:40:57 -0800
From:	Peter Hurley <peter@...leysoftware.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Jiri Slaby <jslaby@...e.cz>, linux-kernel@...r.kernel.org,
	Peter Hurley <peter@...leysoftware.com>
Subject: [PATCH v3 08/19] tty: Reset c_line from driver's init_termios

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@...leysoftware.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 a054d03..d5104b0 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -745,9 +745,6 @@ 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);
 }
 
 /**
-- 
2.7.0