tty: Fix race in tty release

[linux-2.6-block.git] / drivers / tty / pty.c

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 60c08ce83782c2514630bfb337d50779707d4a01..d6579a9064c480db17c29559d2318b2d137337fb 100644 (file)
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -282,6 +282,17 @@ done:
        return 0;
 }
 
+/**
+ *     pty_common_install              -       set up the pty pair
+ *     @driver: the pty driver
+ *     @tty: the tty being instantiated
+ *     @bool: legacy, true if this is BSD style
+ *
+ *     Perform the initial set up for the tty/pty pair. Called from the
+ *     tty layer when the port is first opened.
+ *
+ *     Locking: the caller must hold the tty_mutex
+ */
 static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
                bool legacy)
 {
@@ -364,6 +375,14 @@ static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
        return pty_common_install(driver, tty, true);
 }
 
+static void pty_remove(struct tty_driver *driver, struct tty_struct *tty)
+{
+       struct tty_struct *pair = tty->link;
+       driver->ttys[tty->index] = NULL;
+       if (pair)
+               pair->driver->ttys[pair->index] = NULL;
+}
+
 static int pty_bsd_ioctl(struct tty_struct *tty,
                         unsigned int cmd, unsigned long arg)
 {
@@ -395,7 +414,8 @@ static const struct tty_operations master_pty_ops_bsd = {
        .set_termios = pty_set_termios,
        .ioctl = pty_bsd_ioctl,
        .cleanup = pty_cleanup,
-       .resize = pty_resize
+       .resize = pty_resize,
+       .remove = pty_remove
 };
 
 static const struct tty_operations slave_pty_ops_bsd = {
@@ -409,7 +429,8 @@ static const struct tty_operations slave_pty_ops_bsd = {
        .unthrottle = pty_unthrottle,
        .set_termios = pty_set_termios,
        .cleanup = pty_cleanup,
-       .resize = pty_resize
+       .resize = pty_resize,
+       .remove = pty_remove
 };
 
 static void __init legacy_pty_init(void)