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-rw-r--r--drivers/tty/pty.c17
-rw-r--r--drivers/tty/tty_io.c3
-rw-r--r--include/linux/tty.h2
-rw-r--r--include/linux/tty_driver.h3
4 files changed, 21 insertions, 4 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 98b6e3bdb000..e809e9d4683c 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -446,8 +446,19 @@ static inline void legacy_pty_init(void) { }
 int pty_limit = NR_UNIX98_PTY_DEFAULT;
 static int pty_limit_min;
 static int pty_limit_max = NR_UNIX98_PTY_MAX;
+static int tty_count;
 static int pty_count;
 
+static inline void pty_inc_count(void)
+{
+	pty_count = (++tty_count) / 2;
+}
+
+static inline void pty_dec_count(void)
+{
+	pty_count = (--tty_count) / 2;
+}
+
 static struct cdev ptmx_cdev;
 
 static struct ctl_table pty_table[] = {
@@ -542,6 +553,7 @@ static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
 
 static void pty_unix98_shutdown(struct tty_struct *tty)
 {
+	tty_driver_remove_tty(tty->driver, tty);
 	/* We have our own method as we don't use the tty index */
 	kfree(tty->termios);
 }
@@ -588,7 +600,8 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
 	 */
 	tty_driver_kref_get(driver);
 	tty->count++;
-	pty_count++;
+	pty_inc_count(); /* tty */
+	pty_inc_count(); /* tty->link */
 	return 0;
 err_free_mem:
 	deinitialize_tty_struct(o_tty);
@@ -602,7 +615,7 @@ err_free_tty:
 
 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 {
-	pty_count--;
+	pty_dec_count();
 }
 
 static const struct tty_operations ptm_unix98_ops = {
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 150e4f747c7d..4f1fc81112e6 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1295,8 +1295,7 @@ static int tty_driver_install_tty(struct tty_driver *driver,
  *
  *	Locking: tty_mutex for now
  */
-static void tty_driver_remove_tty(struct tty_driver *driver,
-						struct tty_struct *tty)
+void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
 {
 	if (driver->ops->remove)
 		driver->ops->remove(driver, tty);
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 44bc0c5617e1..5f2ede82b3d6 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -421,6 +421,8 @@ extern void tty_driver_flush_buffer(struct tty_struct *tty);
 extern void tty_throttle(struct tty_struct *tty);
 extern void tty_unthrottle(struct tty_struct *tty);
 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
+extern void tty_driver_remove_tty(struct tty_driver *driver,
+				  struct tty_struct *tty);
 extern void tty_shutdown(struct tty_struct *tty);
 extern void tty_free_termios(struct tty_struct *tty);
 extern int is_current_pgrp_orphaned(void);
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 9deeac855240..ecdaeb98b293 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -47,6 +47,9 @@
  *
  * 	This routine is called synchronously when a particular tty device
  *	is closed for the last time freeing up the resources.
+ *	Note that tty_shutdown() is not called if ops->shutdown is defined.
+ *	This means one is responsible to take care of calling ops->remove (e.g.
+ *	via tty_driver_remove_tty) and releasing tty->termios.
  *
  *
  * void (*cleanup)(struct tty_struct * tty);