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
  19 static 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  */
  27 void usb_register_notify(struct notifier_block *nb)
  28 {
  29         blocking_notifier_chain_register(&usb_notifier_list, nb);
  30 }
  31 EXPORT_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  */
  40 void usb_unregister_notify(struct notifier_block *nb)
  41 {
  42         blocking_notifier_chain_unregister(&usb_notifier_list, nb);
  43 }
  44 EXPORT_SYMBOL_GPL(usb_unregister_notify);
  45
  46
  47 void usb_notify_add_device(struct usb_device *udev)
  48 {
  49         blocking_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
  50 }
  51
  52 void 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
  61 void usb_notify_add_bus(struct usb_bus *ubus)
  62 {
  63         blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
  64 }
  65
  66 void usb_notify_remove_bus(struct usb_bus *ubus)
  67 {
  68         blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
  69 }