USB: usb-serial: replace shutdown with disconnect, release

This patch (as1254) splits up the shutdown method of usb_serial_driver
into a disconnect and a release method.

The problem is that the usb-serial core was calling shutdown during
disconnect handling, but drivers didn't expect it to be called until
after all the open file references had been closed.  The result was an
oops when the close method tried to use memory that had been
deallocated by shutdown.

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

1 files changed, 13 insertions, 16 deletions

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index da890f030fa..d595aa5586a 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -141,6 +141,14 @@ static void destroy_serial(struct kref *kref)
 	if (serial->minor != SERIAL_TTY_NO_MINOR)
 		return_serial(serial);
 
+	serial->type->release(serial);
+
+	for (i = 0; i < serial->num_ports; ++i) {
+		port = serial->port[i];
+		if (port)
+			put_device(&port->dev);
+	}
+
 	/* 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 */
@@ -148,9 +156,8 @@ static void destroy_serial(struct kref *kref)
 		for (i = serial->num_ports;
 					i < serial->num_port_pointers; ++i) {
 			port = serial->port[i];
-			if (!port)
-				continue;
-			port_free(port);
+			if (port)
+				port_free(port);
 		}
 	}
 
@@ -1118,10 +1125,6 @@ void usb_serial_disconnect(struct usb_interface *interface)
 	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) {
@@ -1153,14 +1156,7 @@ void usb_serial_disconnect(struct usb_interface *interface)
 			}
 		}
 	}
-	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;
-		}
-	}
+	serial->type->disconnect(serial);
 
 	/* let the last holder of this object
 	 * cause it to be cleaned up */
@@ -1338,7 +1334,8 @@ static void fixup_generic(struct usb_serial_driver *device)
 	set_to_generic_if_null(device, chars_in_buffer);
 	set_to_generic_if_null(device, read_bulk_callback);
 	set_to_generic_if_null(device, write_bulk_callback);
-	set_to_generic_if_null(device, shutdown);
+	set_to_generic_if_null(device, disconnect);
+	set_to_generic_if_null(device, release);
 }
 
 int usb_serial_register(struct usb_serial_driver *driver)