1 files changed, 68 insertions, 50 deletions

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 7c4447a5c0f4..e72ee629cead 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -47,10 +47,13 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
 	set_bit(TTY_IO_ERROR, &tty->flags);
 	wake_up_interruptible(&tty->read_wait);
 	wake_up_interruptible(&tty->write_wait);
+	spin_lock_irq(&tty->ctrl_lock);
 	tty->packet = 0;
+	spin_unlock_irq(&tty->ctrl_lock);
 	/* Review - krefs on tty_link ?? */
 	if (!tty->link)
 		return;
+	tty_flush_to_ldisc(tty->link);
 	set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
 	wake_up_interruptible(&tty->link->read_wait);
 	wake_up_interruptible(&tty->link->write_wait);
@@ -64,9 +67,7 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
 			mutex_unlock(&devpts_mutex);
 		}
 #endif
-		tty_unlock(tty);
 		tty_vhangup(tty->link);
-		tty_lock(tty);
 	}
 }
 
@@ -87,19 +88,6 @@ static void pty_unthrottle(struct tty_struct *tty)
 }
 
 /**
- *	pty_space	-	report space left for writing
- *	@to: tty we are writing into
- *
- *	Limit the buffer space used by ptys to 8k.
- */
-
-static int pty_space(struct tty_struct *to)
-{
-	int n = tty_buffer_space_avail(to->port);
-	return min(n, 8192);
-}
-
-/**
  *	pty_write		-	write to a pty
  *	@tty: the tty we write from
  *	@buf: kernel buffer of data
@@ -140,7 +128,7 @@ static int pty_write_room(struct tty_struct *tty)
 {
 	if (tty->stopped)
 		return 0;
-	return pty_space(tty->link);
+	return tty_buffer_space_avail(tty->link->port);
 }
 
 /**
@@ -178,21 +166,21 @@ static int pty_get_lock(struct tty_struct *tty, int __user *arg)
 /* Set the packet mode on a pty */
 static int pty_set_pktmode(struct tty_struct *tty, int __user *arg)
 {
-	unsigned long flags;
 	int pktmode;
 
 	if (get_user(pktmode, arg))
 		return -EFAULT;
 
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
+	spin_lock_irq(&tty->ctrl_lock);
 	if (pktmode) {
 		if (!tty->packet) {
-			tty->packet = 1;
 			tty->link->ctrl_status = 0;
+			smp_mb();
+			tty->packet = 1;
 		}
 	} else
 		tty->packet = 0;
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+	spin_unlock_irq(&tty->ctrl_lock);
 
 	return 0;
 }
@@ -207,15 +195,15 @@ static int pty_get_pktmode(struct tty_struct *tty, int __user *arg)
 /* Send a signal to the slave */
 static int pty_signal(struct tty_struct *tty, int sig)
 {
-	unsigned long flags;
 	struct pid *pgrp;
 
-	if (tty->link) {
-		spin_lock_irqsave(&tty->link->ctrl_lock, flags);
-		pgrp = get_pid(tty->link->pgrp);
-		spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
+	if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP)
+		return -EINVAL;
 
-		kill_pgrp(pgrp, sig, 1);
+	if (tty->link) {
+		pgrp = tty_get_pgrp(tty->link);
+		if (pgrp)
+			kill_pgrp(pgrp, sig, 1);
 		put_pid(pgrp);
 	}
 	return 0;
@@ -224,16 +212,21 @@ static int pty_signal(struct tty_struct *tty, int sig)
 static void pty_flush_buffer(struct tty_struct *tty)
 {
 	struct tty_struct *to = tty->link;
-	unsigned long flags;
+	struct tty_ldisc *ld;
 
 	if (!to)
 		return;
-	/* tty_buffer_flush(to); FIXME */
+
+	ld = tty_ldisc_ref(to);
+	tty_buffer_flush(to, ld);
+	if (ld)
+		tty_ldisc_deref(ld);
+
 	if (to->packet) {
-		spin_lock_irqsave(&tty->ctrl_lock, flags);
+		spin_lock_irq(&tty->ctrl_lock);
 		tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
 		wake_up_interruptible(&to->read_wait);
-		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+		spin_unlock_irq(&tty->ctrl_lock);
 	}
 }
 
@@ -262,6 +255,32 @@ out:
 static void pty_set_termios(struct tty_struct *tty,
 					struct ktermios *old_termios)
 {
+	/* See if packet mode change of state. */
+	if (tty->link && tty->link->packet) {
+		int extproc = (old_termios->c_lflag & EXTPROC) |
+				(tty->termios.c_lflag & EXTPROC);
+		int old_flow = ((old_termios->c_iflag & IXON) &&
+				(old_termios->c_cc[VSTOP] == '\023') &&
+				(old_termios->c_cc[VSTART] == '\021'));
+		int new_flow = (I_IXON(tty) &&
+				STOP_CHAR(tty) == '\023' &&
+				START_CHAR(tty) == '\021');
+		if ((old_flow != new_flow) || extproc) {
+			spin_lock_irq(&tty->ctrl_lock);
+			if (old_flow != new_flow) {
+				tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);
+				if (new_flow)
+					tty->ctrl_status |= TIOCPKT_DOSTOP;
+				else
+					tty->ctrl_status |= TIOCPKT_NOSTOP;
+			}
+			if (extproc)
+				tty->ctrl_status |= TIOCPKT_IOCTL;
+			spin_unlock_irq(&tty->ctrl_lock);
+			wake_up_interruptible(&tty->link->read_wait);
+		}
+	}
+
 	tty->termios.c_cflag &= ~(CSIZE | PARENB);
 	tty->termios.c_cflag |= (CS8 | CREAD);
 }
@@ -278,7 +297,6 @@ static void pty_set_termios(struct tty_struct *tty,
 static int pty_resize(struct tty_struct *tty,  struct winsize *ws)
 {
 	struct pid *pgrp, *rpgrp;
-	unsigned long flags;
 	struct tty_struct *pty = tty->link;
 
 	/* For a PTY we need to lock the tty side */
@@ -286,17 +304,9 @@ static int pty_resize(struct tty_struct *tty,  struct winsize *ws)
 	if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
 		goto done;
 
-	/* Get the PID values and reference them so we can
-	   avoid holding the tty ctrl lock while sending signals.
-	   We need to lock these individually however. */
-
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
-	pgrp = get_pid(tty->pgrp);
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-
-	spin_lock_irqsave(&pty->ctrl_lock, flags);
-	rpgrp = get_pid(pty->pgrp);
-	spin_unlock_irqrestore(&pty->ctrl_lock, flags);
+	/* Signal the foreground process group of both ptys */
+	pgrp = tty_get_pgrp(tty);
+	rpgrp = tty_get_pgrp(pty);
 
 	if (pgrp)
 		kill_pgrp(pgrp, SIGWINCH, 1);
@@ -327,26 +337,26 @@ static void pty_start(struct tty_struct *tty)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
 	if (tty->link && tty->link->packet) {
+		spin_lock_irqsave(&tty->ctrl_lock, flags);
 		tty->ctrl_status &= ~TIOCPKT_STOP;
 		tty->ctrl_status |= TIOCPKT_START;
+		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 		wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
 	}
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 }
 
 static void pty_stop(struct tty_struct *tty)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
 	if (tty->link && tty->link->packet) {
+		spin_lock_irqsave(&tty->ctrl_lock, flags);
 		tty->ctrl_status &= ~TIOCPKT_START;
 		tty->ctrl_status |= TIOCPKT_STOP;
+		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 		wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
 	}
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 }
 
 /**
@@ -368,6 +378,10 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
 	int idx = tty->index;
 	int retval = -ENOMEM;
 
+	/* Opening the slave first has always returned -EIO */
+	if (driver->subtype != PTY_TYPE_MASTER)
+		return -EIO;
+
 	ports[0] = kmalloc(sizeof **ports, GFP_KERNEL);
 	ports[1] = kmalloc(sizeof **ports, GFP_KERNEL);
 	if (!ports[0] || !ports[1])
@@ -380,6 +394,9 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
 	if (!o_tty)
 		goto err_put_module;
 
+	tty_set_lock_subclass(o_tty);
+	lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE);
+
 	if (legacy) {
 		/* We always use new tty termios data so we can do this
 		   the easy way .. */
@@ -404,19 +421,22 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
 	 * Everything allocated ... set up the o_tty structure.
 	 */
 	tty_driver_kref_get(driver->other);
-	if (driver->subtype == PTY_TYPE_MASTER)
-		o_tty->count++;
 	/* Establish the links in both directions */
 	tty->link   = o_tty;
 	o_tty->link = tty;
 	tty_port_init(ports[0]);
 	tty_port_init(ports[1]);
+	tty_buffer_set_limit(ports[0], 8192);
+	tty_buffer_set_limit(ports[1], 8192);
 	o_tty->port = ports[0];
 	tty->port = ports[1];
 	o_tty->port->itty = o_tty;
 
+	tty_buffer_set_lock_subclass(o_tty->port);
+
 	tty_driver_kref_get(driver);
 	tty->count++;
+	o_tty->count++;
 	return 0;
 err_free_termios:
 	if (legacy)
@@ -489,7 +509,6 @@ static const struct tty_operations master_pty_ops_bsd = {
 	.flush_buffer = pty_flush_buffer,
 	.chars_in_buffer = pty_chars_in_buffer,
 	.unthrottle = pty_unthrottle,
-	.set_termios = pty_set_termios,
 	.ioctl = pty_bsd_ioctl,
 	.cleanup = pty_cleanup,
 	.resize = pty_resize,
@@ -666,7 +685,6 @@ static const struct tty_operations ptm_unix98_ops = {
 	.flush_buffer = pty_flush_buffer,
 	.chars_in_buffer = pty_chars_in_buffer,
 	.unthrottle = pty_unthrottle,
-	.set_termios = pty_set_termios,
 	.ioctl = pty_unix98_ioctl,
 	.resize = pty_resize,
 	.shutdown = pty_unix98_shutdown,