Merge branch 'x86/cpufeature' into irq/numa
[sfrench/cifs-2.6.git] / drivers / usb / serial / usb-serial.c
index 2a70563bbee1003008a20a0f48b880a4503db9ab..f331e2bde88acbb0c2b4e36fee01eff68ffc9b5c 100644 (file)
@@ -137,22 +137,10 @@ static void destroy_serial(struct kref *kref)
 
        dbg("%s - %s", __func__, serial->type->description);
 
-       serial->type->shutdown(serial);
-
        /* return the minor range that this device had */
        if (serial->minor != SERIAL_TTY_NO_MINOR)
                return_serial(serial);
 
-       for (i = 0; i < serial->num_ports; ++i)
-               serial->port[i]->port.count = 0;
-
-       /* the ports are cleaned up and released in port_release() */
-       for (i = 0; i < serial->num_ports; ++i)
-               if (serial->port[i]->dev.parent != NULL) {
-                       device_unregister(&serial->port[i]->dev);
-                       serial->port[i] = NULL;
-               }
-
        /* If this is a "fake" port, we have to clean it up here, as it will
         * not get cleaned up in port_release() as it was never registered with
         * the driver core */
@@ -187,7 +175,7 @@ static int serial_open (struct tty_struct *tty, struct file *filp)
        struct usb_serial *serial;
        struct usb_serial_port *port;
        unsigned int portNumber;
-       int retval;
+       int retval = 0;
 
        dbg("%s", __func__);
 
@@ -198,21 +186,24 @@ static int serial_open (struct tty_struct *tty, struct file *filp)
                return -ENODEV;
        }
 
+       mutex_lock(&serial->disc_mutex);
        portNumber = tty->index - serial->minor;
        port = serial->port[portNumber];
-       if (!port) {
-               retval = -ENODEV;
-               goto bailout_kref_put;
-       }
-
-       if (port->serial->disconnected) {
+       if (!port || serial->disconnected)
                retval = -ENODEV;
-               goto bailout_kref_put;
-       }
+       else
+               get_device(&port->dev);
+       /*
+        * Note: Our locking order requirement does not allow port->mutex
+        * to be acquired while serial->disc_mutex is held.
+        */
+       mutex_unlock(&serial->disc_mutex);
+       if (retval)
+               goto bailout_serial_put;
 
        if (mutex_lock_interruptible(&port->mutex)) {
                retval = -ERESTARTSYS;
-               goto bailout_kref_put;
+               goto bailout_port_put;
        }
 
        ++port->port.count;
@@ -232,14 +223,20 @@ static int serial_open (struct tty_struct *tty, struct file *filp)
                        goto bailout_mutex_unlock;
                }
 
-               retval = usb_autopm_get_interface(serial->interface);
+               mutex_lock(&serial->disc_mutex);
+               if (serial->disconnected)
+                       retval = -ENODEV;
+               else
+                       retval = usb_autopm_get_interface(serial->interface);
                if (retval)
                        goto bailout_module_put;
+
                /* only call the device specific open if this
                 * is the first time the port is opened */
                retval = serial->type->open(tty, port, filp);
                if (retval)
                        goto bailout_interface_put;
+               mutex_unlock(&serial->disc_mutex);
        }
 
        mutex_unlock(&port->mutex);
@@ -248,13 +245,16 @@ static int serial_open (struct tty_struct *tty, struct file *filp)
 bailout_interface_put:
        usb_autopm_put_interface(serial->interface);
 bailout_module_put:
+       mutex_unlock(&serial->disc_mutex);
        module_put(serial->type->driver.owner);
 bailout_mutex_unlock:
        port->port.count = 0;
        tty->driver_data = NULL;
        tty_port_tty_set(&port->port, NULL);
        mutex_unlock(&port->mutex);
-bailout_kref_put:
+bailout_port_put:
+       put_device(&port->dev);
+bailout_serial_put:
        usb_serial_put(serial);
        return retval;
 }
@@ -262,6 +262,9 @@ bailout_kref_put:
 static void serial_close(struct tty_struct *tty, struct file *filp)
 {
        struct usb_serial_port *port = tty->driver_data;
+       struct usb_serial *serial;
+       struct module *owner;
+       int count;
 
        if (!port)
                return;
@@ -269,6 +272,8 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
        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);
@@ -281,7 +286,7 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
                 * this before we drop the port count. The call is protected
                 * by the port mutex
                 */
-               port->serial->type->close(tty, port, filp);
+               serial->type->close(tty, port, filp);
 
        if (port->port.count == (port->console ? 2 : 1)) {
                struct tty_struct *tty = tty_port_tty_get(&port->port);
@@ -295,17 +300,23 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
                }
        }
 
-       if (port->port.count == 1) {
-               mutex_lock(&port->serial->disc_mutex);
-               if (!port->serial->disconnected)
-                       usb_autopm_put_interface(port->serial->interface);
-               mutex_unlock(&port->serial->disc_mutex);
-               module_put(port->serial->type->driver.owner);
-       }
        --port->port.count;
-
+       count = port->port.count;
        mutex_unlock(&port->mutex);
-       usb_serial_put(port->serial);
+       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);
+       }
+       usb_serial_put(serial);
+
+       /* Mustn't dereference serial any more */
+       if (count == 0)
+               module_put(owner);
 }
 
 static int serial_write(struct tty_struct *tty, const unsigned char *buf,
@@ -549,7 +560,13 @@ static void kill_traffic(struct usb_serial_port *port)
 
 static void port_free(struct usb_serial_port *port)
 {
+       /*
+        * Stop all the traffic before cancelling the work, so that
+        * nobody will restart it by calling usb_serial_port_softint.
+        */
        kill_traffic(port);
+       cancel_work_sync(&port->work);
+
        usb_free_urb(port->read_urb);
        usb_free_urb(port->write_urb);
        usb_free_urb(port->interrupt_in_urb);
@@ -558,7 +575,6 @@ static void port_free(struct usb_serial_port *port)
        kfree(port->bulk_out_buffer);
        kfree(port->interrupt_in_buffer);
        kfree(port->interrupt_out_buffer);
-       flush_scheduled_work();         /* port->work */
        kfree(port);
 }
 
@@ -958,6 +974,7 @@ int usb_serial_probe(struct usb_interface *interface,
                if (retval > 0) {
                        /* quietly accept this device, but don't bind to a
                           serial port as it's about to disappear */
+                       serial->num_ports = 0;
                        goto exit;
                }
        }
@@ -1043,6 +1060,12 @@ void usb_serial_disconnect(struct usb_interface *interface)
        usb_set_intfdata(interface, NULL);
        /* must set a flag, to signal subdrivers */
        serial->disconnected = 1;
+       mutex_unlock(&serial->disc_mutex);
+
+       /* Unfortunately, many of the sub-drivers expect the port structures
+        * to exist when their shutdown method is called, so we have to go
+        * through this awkward two-step unregistration procedure.
+        */
        for (i = 0; i < serial->num_ports; ++i) {
                port = serial->port[i];
                if (port) {
@@ -1052,11 +1075,21 @@ void usb_serial_disconnect(struct usb_interface *interface)
                                tty_kref_put(tty);
                        }
                        kill_traffic(port);
+                       cancel_work_sync(&port->work);
+                       device_del(&port->dev);
+               }
+       }
+       serial->type->shutdown(serial);
+       for (i = 0; i < serial->num_ports; ++i) {
+               port = serial->port[i];
+               if (port) {
+                       put_device(&port->dev);
+                       serial->port[i] = NULL;
                }
        }
+
        /* let the last holder of this object
         * cause it to be cleaned up */
-       mutex_unlock(&serial->disc_mutex);
        usb_serial_put(serial);
        dev_info(dev, "device disconnected\n");
 }