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![Alan Stern](/assets/img/avatar_default.png)
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>
183 lines
4.1 KiB
C
183 lines
4.1 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/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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if (port->dev_state != PORT_REGISTERING)
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goto exit;
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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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if (port->dev_state != PORT_UNREGISTERING)
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return retval;
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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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