1 files changed, 100 insertions, 44 deletions

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index f331e2bde88a..1967a7edc10c 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -238,9 +238,11 @@ static int serial_open (struct tty_struct *tty, struct file *filp)
                         goto bailout_interface_put;
                 mutex_unlock(&serial->disc_mutex);
         }
-
         mutex_unlock(&port->mutex);
-        return 0;
+        /* Now do the correct tty layer semantics */
+        retval = tty_port_block_til_ready(&port->port, tty, filp);
+        if (retval == 0)
+                return 0;
 
 bailout_interface_put:
         usb_autopm_put_interface(serial->interface);
@@ -259,64 +261,89 @@ bailout_serial_put:
         return retval;
 }
 
-static void serial_close(struct tty_struct *tty, struct file *filp)
+/**
+ *      serial_do_down          -       shut down hardware
+ *      @port: port to shut down
+ *
+ *      Shut down a USB port unless it is the console. We never shut down the
+ *      console hardware as it will always be in use.
+ *
+ *      Don't free any resources at this point
+ */
+static void serial_do_down(struct usb_serial_port *port)
 {
-        struct usb_serial_port *port = tty->driver_data;
+        struct usb_serial_driver *drv = port->serial->type;
         struct usb_serial *serial;
         struct module *owner;
-        int count;
 
-        if (!port)
+        /* The console is magical, do not hang up the console hardware
+           or there will be tears */
+        if (port->console)
                 return;
 
-        dbg("%s - port %d", __func__, port->number);
-
         mutex_lock(&port->mutex);
         serial = port->serial;
         owner = serial->type->driver.owner;
 
-        if (port->port.count == 0) {
-                mutex_unlock(&port->mutex);
-                return;
-        }
-
-        if (port->port.count == 1)
-                /* only call the device specific close if this
-                 * port is being closed by the last owner. Ensure we do
-                 * this before we drop the port count. The call is protected
-                 * by the port mutex
-                 */
-                serial->type->close(tty, port, filp);
-
-        if (port->port.count == (port->console ? 2 : 1)) {
-                struct tty_struct *tty = tty_port_tty_get(&port->port);
-                if (tty) {
-                        /* We must do this before we drop the port count to
-                           zero. */
-                        if (tty->driver_data)
-                                tty->driver_data = NULL;
-                        tty_port_tty_set(&port->port, NULL);
-                        tty_kref_put(tty);
-                }
-        }
+        if (drv->close)
+                drv->close(port);
 
-        --port->port.count;
-        count = port->port.count;
         mutex_unlock(&port->mutex);
-        put_device(&port->dev);
+}
+
+/**
+ *      serial_do_free          -       free resources post close/hangup
+ *      @port: port to free up
+ *
+ *      Do the resource freeing and refcount dropping for the port. We must
+ *      be careful about ordering and we must avoid freeing up the console.
+ */
 
+static void serial_do_free(struct usb_serial_port *port)
+{
+        struct usb_serial *serial;
+        struct module *owner;
+
+        /* The console is magical, do not hang up the console hardware
+           or there will be tears */
+        if (port->console)
+                return;
+
+        serial = port->serial;
+        owner = serial->type->driver.owner;
+        put_device(&port->dev);
         /* Mustn't dereference port any more */
-        if (count == 0) {
-                mutex_lock(&serial->disc_mutex);
-                if (!serial->disconnected)
-                        usb_autopm_put_interface(serial->interface);
-                mutex_unlock(&serial->disc_mutex);
-        }
+        mutex_lock(&serial->disc_mutex);
+        if (!serial->disconnected)
+                usb_autopm_put_interface(serial->interface);
+        mutex_unlock(&serial->disc_mutex);
         usb_serial_put(serial);
-
         /* Mustn't dereference serial any more */
-        if (count == 0)
-                module_put(owner);
+        module_put(owner);
+}
+
+static void serial_close(struct tty_struct *tty, struct file *filp)
+{
+        struct usb_serial_port *port = tty->driver_data;
+
+        dbg("%s - port %d", __func__, port->number);
+
+
+        if (tty_port_close_start(&port->port, tty, filp) == 0)
+                return;
+
+        serial_do_down(port);           
+        tty_port_close_end(&port->port, tty);
+        tty_port_tty_set(&port->port, NULL);
+        serial_do_free(port);
+}
+
+static void serial_hangup(struct tty_struct *tty)
+{
+        struct usb_serial_port *port = tty->driver_data;
+        serial_do_down(port);
+        tty_port_hangup(&port->port);
+        serial_do_free(port);
 }
 
 static int serial_write(struct tty_struct *tty, const unsigned char *buf,
@@ -648,6 +675,29 @@ static struct usb_serial_driver *search_serial_device(
         return NULL;
 }
 
+static int serial_carrier_raised(struct tty_port *port)
+{
+        struct usb_serial_port *p = container_of(port, struct usb_serial_port, port);
+        struct usb_serial_driver *drv = p->serial->type;
+        if (drv->carrier_raised)
+                return drv->carrier_raised(p);
+        /* No carrier control - don't block */
+        return 1;       
+}
+
+static void serial_dtr_rts(struct tty_port *port, int on)
+{
+        struct usb_serial_port *p = container_of(port, struct usb_serial_port, port);
+        struct usb_serial_driver *drv = p->serial->type;
+        if (drv->dtr_rts)
+                drv->dtr_rts(p, on);
+}
+
+static const struct tty_port_operations serial_port_ops = {
+        .carrier_raised = serial_carrier_raised,
+        .dtr_rts = serial_dtr_rts,
+};
+
 int usb_serial_probe(struct usb_interface *interface,
                                const struct usb_device_id *id)
 {
@@ -841,6 +891,7 @@ int usb_serial_probe(struct usb_interface *interface,
                 if (!port)
                         goto probe_error;
                 tty_port_init(&port->port);
+                port->port.ops = &serial_port_ops;
                 port->serial = serial;
                 spin_lock_init(&port->lock);
                 mutex_init(&port->mutex);
@@ -1071,6 +1122,9 @@ void usb_serial_disconnect(struct usb_interface *interface)
                 if (port) {
                         struct tty_struct *tty = tty_port_tty_get(&port->port);
                         if (tty) {
+                                /* The hangup will occur asynchronously but
+                                   the object refcounts will sort out all the
+                                   cleanup */
                                 tty_hangup(tty);
                                 tty_kref_put(tty);
                         }
@@ -1135,6 +1189,7 @@ static const struct tty_operations serial_ops = {
         .open =                 serial_open,
         .close =                serial_close,
         .write =                serial_write,
+        .hangup =               serial_hangup,
         .write_room =           serial_write_room,
         .ioctl =                serial_ioctl,
         .set_termios =          serial_set_termios,
@@ -1147,6 +1202,7 @@ static const struct tty_operations serial_ops = {
         .proc_fops =            &serial_proc_fops,
 };
 
+
 struct tty_driver *usb_serial_tty_driver;
 
 static int __init usb_serial_init(void)