tty: Use 'disc' for line discipline index name

BugLink: http://bugs.launchpad.net/bugs/1709126

tty->ldisc is a ptr to struct tty_ldisc, but unfortunately 'ldisc' is
also used as a parameter or local name to refer to the line discipline
index value (ie, N_TTY, N_GSM, etc.); instead prefer the name used
by the line discipline registration/ref counting functions.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit c12da96f)
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Marcelo Cerri <marcelo.cerri@canonical.com>
Acked-by: Benjamin M Romer <benjamin.romer@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/tty/tty_io.c

@@ -2651,13 +2651,13 @@ static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t _
 
 static int tiocsetd(struct tty_struct *tty, int __user *p)
 {
-	int ldisc;
+	int disc;
 	int ret;
 
-	if (get_user(ldisc, p))
+	if (get_user(disc, p))
 		return -EFAULT;
 
-	ret = tty_set_ldisc(tty, ldisc);
+	ret = tty_set_ldisc(tty, disc);
 
 	return ret;
 }

drivers/tty/tty_ldisc.c

@@ -412,7 +412,7 @@ EXPORT_SYMBOL_GPL(tty_ldisc_flush);
 /**
  *	tty_set_termios_ldisc		-	set ldisc field
  *	@tty: tty structure
- *	@num: line discipline number
+ *	@disc: line discipline number
  *
  *	This is probably overkill for real world processors but
  *	they are not on hot paths so a little discipline won't do
@@ -425,10 +425,10 @@ EXPORT_SYMBOL_GPL(tty_ldisc_flush);
  *	Locking: takes termios_rwsem
  */
 
-static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
+static void tty_set_termios_ldisc(struct tty_struct *tty, int disc)
 {
 	down_write(&tty->termios_rwsem);
-	tty->termios.c_line = num;
+	tty->termios.c_line = disc;
 	up_write(&tty->termios_rwsem);
 
 	tty->disc_data = NULL;
@@ -526,12 +526,12 @@ static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)
  *	the close of one side of a tty/pty pair, and eventually hangup.
  */
 
-int tty_set_ldisc(struct tty_struct *tty, int ldisc)
+int tty_set_ldisc(struct tty_struct *tty, int disc)
 {
 	int retval;
 	struct tty_ldisc *old_ldisc, *new_ldisc;
 
-	new_ldisc = tty_ldisc_get(tty, ldisc);
+	new_ldisc = tty_ldisc_get(tty, disc);
 	if (IS_ERR(new_ldisc))
 		return PTR_ERR(new_ldisc);
 
@@ -546,7 +546,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 	}
 
 	/* Check the no-op case */
-	if (tty->ldisc->ops->num == ldisc)
+	if (tty->ldisc->ops->num == disc)
 		goto out;
 
 	if (test_bit(TTY_HUPPED, &tty->flags)) {
@@ -562,7 +562,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 
 	/* Now set up the new line discipline. */
 	tty->ldisc = new_ldisc;
-	tty_set_termios_ldisc(tty, ldisc);
+	tty_set_termios_ldisc(tty, disc);
 
 	retval = tty_ldisc_open(tty, new_ldisc);
 	if (retval < 0) {
@@ -634,15 +634,15 @@ static void tty_reset_termios(struct tty_struct *tty)
 /**
  *	tty_ldisc_reinit	-	reinitialise the tty ldisc
  *	@tty: tty to reinit
- *	@ldisc: line discipline to reinitialize
+ *	@disc: line discipline to reinitialize
  *
  *	Switch the tty to a line discipline and leave the ldisc
  *	state closed
  */
 
-static int tty_ldisc_reinit(struct tty_struct *tty, int ldisc)
+static int tty_ldisc_reinit(struct tty_struct *tty, int disc)
 {
-	struct tty_ldisc *ld = tty_ldisc_get(tty, ldisc);
+	struct tty_ldisc *ld = tty_ldisc_get(tty, disc);
 
 	if (IS_ERR(ld))
 		return -1;
@@ -653,7 +653,7 @@ static int tty_ldisc_reinit(struct tty_struct *tty, int ldisc)
 	 *	Switch the line discipline back
 	 */
 	tty->ldisc = ld;
-	tty_set_termios_ldisc(tty, ldisc);
+	tty_set_termios_ldisc(tty, disc);
 
 	return 0;
 }

include/linux/tty.h

@@ -580,7 +580,7 @@ static inline int tty_port_users(struct tty_port *port)
 
 extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
 extern int tty_unregister_ldisc(int disc);
-extern int tty_set_ldisc(struct tty_struct *tty, int ldisc);
+extern int tty_set_ldisc(struct tty_struct *tty, int disc);
 extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty);
 extern void tty_ldisc_release(struct tty_struct *tty);
 extern void tty_ldisc_init(struct tty_struct *tty);