usb-serial: new API for driver registration
This patch (as1522) adds two new routines to the usb-serial core, for
registering and unregistering serial drivers. Instead of registering
the usb_driver and usb_serial_drivers separately, with error checking
for each one, the drivers can all be registered and unregistered by a
single function call. This reduces duplicated code.
More importantly, the new core routines change the order in which the
drivers are registered. Currently the usb-serial drivers are all
registered first and the usb_driver is done last, which leaves a
window for problems. A udev script may quickly add a new dynamic-ID
for a usb-serial driver, causing the corresponding usb_driver to be
probed. If the usb_driver hasn't been registered yet then an oops
will occur.
The new routine prevents such problems by registering the usb_driver
first. To insure that it gets probed properly for already-attached
serial devices, we call driver_attach() after all the usb-serial
drivers have been registered.
Along with adding the new routines, the patch modifies the "generic"
serial driver to use them. Further patches will similarly modify all
the other in-tree USB serial drivers.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 2a2fa2d..664deb6 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -54,7 +54,6 @@
.probe = generic_probe,
.disconnect = usb_serial_disconnect,
.id_table = generic_serial_ids,
- .no_dynamic_id = 1,
};
/* All of the device info needed for the Generic Serial Converter */
@@ -64,7 +63,6 @@
.name = "generic",
},
.id_table = generic_device_ids,
- .usb_driver = &generic_driver,
.num_ports = 1,
.disconnect = usb_serial_generic_disconnect,
.release = usb_serial_generic_release,
@@ -73,6 +71,10 @@
.resume = usb_serial_generic_resume,
};
+static struct usb_serial_driver * const serial_drivers[] = {
+ &usb_serial_generic_device, NULL
+};
+
static int generic_probe(struct usb_interface *interface,
const struct usb_device_id *id)
{
@@ -97,13 +99,7 @@
USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
/* register our generic driver with ourselves */
- retval = usb_serial_register(&usb_serial_generic_device);
- if (retval)
- goto exit;
- retval = usb_register(&generic_driver);
- if (retval)
- usb_serial_deregister(&usb_serial_generic_device);
-exit:
+ retval = usb_serial_register_drivers(&generic_driver, serial_drivers);
#endif
return retval;
}
@@ -112,8 +108,7 @@
{
#ifdef CONFIG_USB_SERIAL_GENERIC
/* remove our generic driver */
- usb_deregister(&generic_driver);
- usb_serial_deregister(&usb_serial_generic_device);
+ usb_serial_deregister_drivers(&generic_driver, serial_drivers);
#endif
}