LXR linux/drivers/usb/core/notify.c

   1/*
   2 * All the USB notify logic
   3 *
   4 * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
   5 *
   6 * notifier functions originally based on those in kernel/sys.c
   7 * but fixed up to not be so broken.
   8 *
   9 */
  10
  11
  12#include <linux/kernel.h>
  13#include <linux/export.h>
  14#include <linux/notifier.h>
  15#include <linux/usb.h>
  16#include <linux/mutex.h>
  17#include "usb.h"
  18
  19static BLOCKING_NOTIFIER_HEAD(usb_notifier_list);
  20
  21/**
  22 * usb_register_notify - register a notifier callback whenever a usb change happens
  23 * @nb: pointer to the notifier block for the callback events.
  24 *
  25 * These changes are either USB devices or busses being added or removed.
  26 */
  27void usb_register_notify(struct notifier_block *nb)
  28{
  29        blocking_notifier_chain_register(&usb_notifier_list, nb);
  30}
  31EXPORT_SYMBOL_GPL(usb_register_notify);
  32
  33/**
  34 * usb_unregister_notify - unregister a notifier callback
  35 * @nb: pointer to the notifier block for the callback events.
  36 *
  37 * usb_register_notify() must have been previously called for this function
  38 * to work properly.
  39 */
  40void usb_unregister_notify(struct notifier_block *nb)
  41{
  42        blocking_notifier_chain_unregister(&usb_notifier_list, nb);
  43}
  44EXPORT_SYMBOL_GPL(usb_unregister_notify);
  45
  46
  47void usb_notify_add_device(struct usb_device *udev)
  48{
  49        blocking_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
  50}
  51
  52void usb_notify_remove_device(struct usb_device *udev)
  53{
  54        /* Protect against simultaneous usbfs open */
  55        mutex_lock(&usbfs_mutex);
  56        blocking_notifier_call_chain(&usb_notifier_list,
  57                        USB_DEVICE_REMOVE, udev);
  58        mutex_unlock(&usbfs_mutex);
  59}
  60
  61void usb_notify_add_bus(struct usb_bus *ubus)
  62{
  63        blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
  64}
  65
  66void usb_notify_remove_bus(struct usb_bus *ubus)
  67{
  68        blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
  69}
  70