USB: usb-serial: call port_probe and port_remove at the right times

This patch (as1253) prevents the usb-serial core from calling a
driver's port_probe and port_remove methods more than once per port.
It also removes some unnecessary try_module_get() calls and adds a
missing port_remove method call in a failure path.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 33 insertions, 18 deletions

diff --git a/drivers/usb/serial/bus.c b/drivers/usb/serial/bus.c
index 83bbb5bca2ef..ba555c528cc6 100644
--- a/drivers/usb/serial/bus.c
+++ b/drivers/usb/serial/bus.c
@@ -59,23 +59,22 @@ static int usb_serial_device_probe(struct device *dev)
                 retval = -ENODEV;
                 goto exit;
         }
+        if (port->dev_state != PORT_REGISTERING)
+                goto exit;
 
         driver = port->serial->type;
         if (driver->port_probe) {
-                if (!try_module_get(driver->driver.owner)) {
-                        dev_err(dev, "module get failed, exiting\n");
-                        retval = -EIO;
-                        goto exit;
-                }
                 retval = driver->port_probe(port);
-                module_put(driver->driver.owner);
                 if (retval)
                         goto exit;
         }
 
         retval = device_create_file(dev, &dev_attr_port_number);
-        if (retval)
+        if (retval) {
+                if (driver->port_remove)
+                        retval = driver->port_remove(port);
                 goto exit;
+        }
 
         minor = port->number;
         tty_register_device(usb_serial_tty_driver, minor, dev);
@@ -98,19 +97,15 @@ static int usb_serial_device_remove(struct device *dev)
         if (!port)
                 return -ENODEV;
 
+        if (port->dev_state != PORT_UNREGISTERING)
+                return retval;
+
         device_remove_file(&port->dev, &dev_attr_port_number);
 
         driver = port->serial->type;
-        if (driver->port_remove) {
-                if (!try_module_get(driver->driver.owner)) {
-                        dev_err(dev, "module get failed, exiting\n");
-                        retval = -EIO;
-                        goto exit;
-                }
+        if (driver->port_remove)
                 retval = driver->port_remove(port);
-                module_put(driver->driver.owner);
-        }
-exit:
+
         minor = port->number;
         tty_unregister_device(usb_serial_tty_driver, minor);
         dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 1967a7edc10c..da890f030fac 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1046,10 +1046,15 @@ int usb_serial_probe(struct usb_interface *interface,
 
                 dev_set_name(&port->dev, "ttyUSB%d", port->number);
                 dbg ("%s - registering %s", __func__, dev_name(&port->dev));
+                port->dev_state = PORT_REGISTERING;
                 retval = device_register(&port->dev);
-                if (retval)
+                if (retval) {
                         dev_err(&port->dev, "Error registering port device, "
                                 "continuing\n");
+                        port->dev_state = PORT_UNREGISTERED;
+                } else {
+                        port->dev_state = PORT_REGISTERED;
+                }
         }
 
         usb_serial_console_init(debug, minor);
@@ -1130,7 +1135,22 @@ void usb_serial_disconnect(struct usb_interface *interface)
                         }
                         kill_traffic(port);
                         cancel_work_sync(&port->work);
-                        device_del(&port->dev);
+                        if (port->dev_state == PORT_REGISTERED) {
+
+                                /* Make sure the port is bound so that the
+                                 * driver's port_remove method is called.
+                                 */
+                                if (!port->dev.driver) {
+                                        int rc;
+
+                                        port->dev.driver =
+                                                        &serial->type->driver;
+                                        rc = device_bind_driver(&port->dev);
+                                }
+                                port->dev_state = PORT_UNREGISTERING;
+                                device_del(&port->dev);
+                                port->dev_state = PORT_UNREGISTERED;
+                        }
                 }
         }
         serial->type->shutdown(serial);