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/notifier.h>
  14 #include <linux/usb.h>
  15 #include <linux/mutex.h>
  16 #include "usb.h"
  17
  18 static BLOCKING_NOTIFIER_HEAD(usb_notifier_list);
  19
  20 /**
  21  * usb_register_notify - register a notifier callback whenever a usb change happens
  22  * @nb: pointer to the notifier block for the callback events.
  23  *
  24  * These changes are either USB devices or busses being added or removed.
  25  */
  26 void usb_register_notify(struct notifier_block *nb)
  27 {
  28         blocking_notifier_chain_register(&usb_notifier_list, nb);
  29 }
  30 EXPORT_SYMBOL_GPL(usb_register_notify);
  31
  32 /**
  33  * usb_unregister_notify - unregister a notifier callback
  34  * @nb: pointer to the notifier block for the callback events.
  35  *
  36  * usb_register_notifier() must have been previously called for this function
  37  * to work properly.
  38  */
  39 void usb_unregister_notify(struct notifier_block *nb)
  40 {
  41         blocking_notifier_chain_unregister(&usb_notifier_list, nb);
  42 }
  43 EXPORT_SYMBOL_GPL(usb_unregister_notify);
  44
  45
  46 void usb_notify_add_device(struct usb_device *udev)
  47 {
  48         blocking_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
  49 }
  50
  51 void usb_notify_remove_device(struct usb_device *udev)
  52 {
  53         /* Protect against simultaneous usbfs open */
  54         mutex_lock(&usbfs_mutex);
  55         blocking_notifier_call_chain(&usb_notifier_list,
  56                         USB_DEVICE_REMOVE, udev);
  57         mutex_unlock(&usbfs_mutex);
  58 }
  59
  60 void usb_notify_add_bus(struct usb_bus *ubus)
  61 {
  62         blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
  63 }
  64
  65 void usb_notify_remove_bus(struct usb_bus *ubus)
  66 {
  67         blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
  68 }