1 files changed, 18 insertions, 4 deletions

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index a3afa0c387cd..05f443c47bbe 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1184,6 +1184,7 @@ int tty_init_termios(struct tty_struct *tty)
         tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
         return 0;
 }
+EXPORT_SYMBOL_GPL(tty_init_termios);
 
 /**
  *      tty_driver_install_tty() - install a tty entry in the driver
@@ -1386,10 +1387,14 @@ EXPORT_SYMBOL(tty_shutdown);
  *              tty_mutex - sometimes only
  *              takes the file list lock internally when working on the list
  *      of ttys that the driver keeps.
+ *
+ *      This method gets called from a work queue so that the driver private
+ *      shutdown ops can sleep (needed for USB at least)
  */
-static void release_one_tty(struct kref *kref)
+static void release_one_tty(struct work_struct *work)
 {
-        struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
+        struct tty_struct *tty =
+                container_of(work, struct tty_struct, hangup_work);
         struct tty_driver *driver = tty->driver;
 
         if (tty->ops->shutdown)
@@ -1407,6 +1412,15 @@ static void release_one_tty(struct kref *kref)
         free_tty_struct(tty);
 }
 
+static void queue_release_one_tty(struct kref *kref)
+{
+        struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
+        /* The hangup queue is now free so we can reuse it rather than
+           waste a chunk of memory for each port */
+        INIT_WORK(&tty->hangup_work, release_one_tty);
+        schedule_work(&tty->hangup_work);
+}
+
 /**
  *      tty_kref_put            -       release a tty kref
  *      @tty: tty device
@@ -1418,7 +1432,7 @@ static void release_one_tty(struct kref *kref)
 void tty_kref_put(struct tty_struct *tty)
 {
         if (tty)
-                kref_put(&tty->kref, release_one_tty);
+                kref_put(&tty->kref, queue_release_one_tty);
 }
 EXPORT_SYMBOL(tty_kref_put);
 
@@ -2085,7 +2099,7 @@ static int tioccons(struct file *file)
  *      the generic functionality existed. This piece of history is preserved
  *      in the expected tty API of posix OS's.
  *
- *      Locking: none, the open fle handle ensures it won't go away.
+ *      Locking: none, the open file handle ensures it won't go away.
  */
 
 static int fionbio(struct file *file, int __user *p)