tty: Add a full port_close function

Now we are extracting out methods for shutdown and the like we can add a
proper tty_port_close method that knows all the innards of the tty closing
process and hides the lot from the caller.

At some point in the future this will be paired with a similar open()
helper and the drivers can stick to hardware management.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 27 insertions, 2 deletions

diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index 9769b1149f76..549bd0fa8bb6 100644
--- a/drivers/char/tty_port.c
+++ b/drivers/char/tty_port.c
@@ -96,6 +96,14 @@ void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
 }
 EXPORT_SYMBOL(tty_port_tty_set);
 
+static void tty_port_shutdown(struct tty_port *port)
+{
+        if (port->ops->shutdown &&
+                test_and_clear_bit(ASYNC_INITIALIZED, &port->flags))
+                        port->ops->shutdown(port);
+
+}
+
 /**
  *      tty_port_hangup         -       hangup helper
  *      @port: tty port
@@ -116,6 +124,7 @@ void tty_port_hangup(struct tty_port *port)
         port->tty = NULL;
         spin_unlock_irqrestore(&port->lock, flags);
         wake_up_interruptible(&port->open_wait);
+        tty_port_shutdown(port);
 }
 EXPORT_SYMBOL(tty_port_hangup);
 
@@ -296,15 +305,17 @@ int tty_port_close_start(struct tty_port *port, struct tty_struct *tty, struct f
 
         if (port->count) {
                 spin_unlock_irqrestore(&port->lock, flags);
+                if (port->ops->drop)
+                        port->ops->drop(port);
                 return 0;
         }
-        port->flags |= ASYNC_CLOSING;
+        set_bit(ASYNC_CLOSING, &port->flags);
         tty->closing = 1;
         spin_unlock_irqrestore(&port->lock, flags);
         /* Don't block on a stalled port, just pull the chain */
         if (tty->flow_stopped)
                 tty_driver_flush_buffer(tty);
-        if (port->flags & ASYNC_INITIALIZED &&
+        if (test_bit(ASYNCB_INITIALIZED, &port->flags) &&
                         port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
                 tty_wait_until_sent(tty, port->closing_wait);
         if (port->drain_delay) {
@@ -318,6 +329,9 @@ int tty_port_close_start(struct tty_port *port, struct tty_struct *tty, struct f
                         timeout = 2 * HZ;
                 schedule_timeout_interruptible(timeout);
         }
+        /* Don't call port->drop for the last reference. Callers will want
+           to drop the last active reference in ->shutdown() or the tty
+           shutdown path */
         return 1;
 }
 EXPORT_SYMBOL(tty_port_close_start);
@@ -348,3 +362,14 @@ void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
         spin_unlock_irqrestore(&port->lock, flags);
 }
 EXPORT_SYMBOL(tty_port_close_end);
+
+void tty_port_close(struct tty_port *port, struct tty_struct *tty,
+                                                        struct file *filp)
+{
+        if (tty_port_close_start(port, tty, filp) == 0)
+                return;
+        tty_port_shutdown(port);
+        tty_port_close_end(port, tty);
+        tty_port_tty_set(port, NULL);
+}
+EXPORT_SYMBOL(tty_port_close);