![Alan Stern](/assets/img/avatar_default.png)
This patch (as1536) fixes a bug in the USB serial core. Unloading and reloading a serial driver while a serial device is plugged in causes errors because of the code in usb_serial_disconnect() that tries to make sure the port_remove method is called. With the new order of driver registration introduced in the 3.4 kernel, this is definitely not the right thing to do (if indeed it ever was). The patch removes that whole section code, along with the mechanism for keeping track of each port's registration state, which is no longer needed. The driver core can handle all that stuff for us. Note: This has been tested only with one or two USB serial drivers. In theory, other drivers might still run into trouble. But if they do, it will be the fault of the drivers, not of this patch -- that is, the drivers will need to be fixed. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-and-tested-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
180 lines
4 KiB
C
180 lines
4 KiB
C
/*
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* USB Serial Converter Bus specific functions
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*
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* Copyright (C) 2002 Greg Kroah-Hartman (greg@kroah.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/tty.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/usb.h>
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#include <linux/usb/serial.h>
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static int usb_serial_device_match(struct device *dev,
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struct device_driver *drv)
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{
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struct usb_serial_driver *driver;
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const struct usb_serial_port *port;
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/*
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* drivers are already assigned to ports in serial_probe so it's
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* a simple check here.
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*/
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port = to_usb_serial_port(dev);
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if (!port)
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return 0;
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driver = to_usb_serial_driver(drv);
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if (driver == port->serial->type)
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return 1;
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return 0;
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}
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static ssize_t show_port_number(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct usb_serial_port *port = to_usb_serial_port(dev);
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return sprintf(buf, "%d\n", port->number - port->serial->minor);
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}
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static DEVICE_ATTR(port_number, S_IRUGO, show_port_number, NULL);
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static int usb_serial_device_probe(struct device *dev)
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{
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struct usb_serial_driver *driver;
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struct usb_serial_port *port;
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int retval = 0;
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int minor;
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port = to_usb_serial_port(dev);
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if (!port) {
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retval = -ENODEV;
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goto exit;
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}
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driver = port->serial->type;
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if (driver->port_probe) {
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retval = driver->port_probe(port);
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if (retval)
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goto exit;
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}
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retval = device_create_file(dev, &dev_attr_port_number);
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if (retval) {
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if (driver->port_remove)
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retval = driver->port_remove(port);
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goto exit;
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}
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minor = port->number;
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tty_register_device(usb_serial_tty_driver, minor, dev);
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dev_info(&port->serial->dev->dev,
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"%s converter now attached to ttyUSB%d\n",
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driver->description, minor);
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exit:
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return retval;
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}
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static int usb_serial_device_remove(struct device *dev)
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{
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struct usb_serial_driver *driver;
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struct usb_serial_port *port;
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int retval = 0;
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int minor;
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port = to_usb_serial_port(dev);
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if (!port)
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return -ENODEV;
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device_remove_file(&port->dev, &dev_attr_port_number);
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driver = port->serial->type;
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if (driver->port_remove)
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retval = driver->port_remove(port);
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minor = port->number;
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tty_unregister_device(usb_serial_tty_driver, minor);
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dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
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driver->description, minor);
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return retval;
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}
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#ifdef CONFIG_HOTPLUG
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static ssize_t store_new_id(struct device_driver *driver,
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const char *buf, size_t count)
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{
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struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
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ssize_t retval = usb_store_new_id(&usb_drv->dynids, driver, buf, count);
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if (retval >= 0 && usb_drv->usb_driver != NULL)
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retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
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&usb_drv->usb_driver->drvwrap.driver,
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buf, count);
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return retval;
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}
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static struct driver_attribute drv_attrs[] = {
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__ATTR(new_id, S_IWUSR, NULL, store_new_id),
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__ATTR_NULL,
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};
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static void free_dynids(struct usb_serial_driver *drv)
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{
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struct usb_dynid *dynid, *n;
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spin_lock(&drv->dynids.lock);
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list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
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list_del(&dynid->node);
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kfree(dynid);
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}
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spin_unlock(&drv->dynids.lock);
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}
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#else
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static struct driver_attribute drv_attrs[] = {
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__ATTR_NULL,
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};
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static inline void free_dynids(struct usb_serial_driver *drv)
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{
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}
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#endif
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struct bus_type usb_serial_bus_type = {
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.name = "usb-serial",
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.match = usb_serial_device_match,
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.probe = usb_serial_device_probe,
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.remove = usb_serial_device_remove,
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.drv_attrs = drv_attrs,
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};
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int usb_serial_bus_register(struct usb_serial_driver *driver)
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{
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int retval;
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driver->driver.bus = &usb_serial_bus_type;
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spin_lock_init(&driver->dynids.lock);
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INIT_LIST_HEAD(&driver->dynids.list);
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retval = driver_register(&driver->driver);
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return retval;
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}
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void usb_serial_bus_deregister(struct usb_serial_driver *driver)
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{
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free_dynids(driver);
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driver_unregister(&driver->driver);
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}
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