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kernel/linux-rt-4.4.41/drivers/usb/core/notify.c 1.76 KB
5113f6f70   김현기   kernel add
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  /*
   * All the USB notify logic
   *
   * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
   *
   * notifier functions originally based on those in kernel/sys.c
   * but fixed up to not be so broken.
   *
   */
  
  
  #include <linux/kernel.h>
  #include <linux/export.h>
  #include <linux/notifier.h>
  #include <linux/usb.h>
  #include <linux/mutex.h>
  #include "usb.h"
  
  static BLOCKING_NOTIFIER_HEAD(usb_notifier_list);
  
  /**
   * usb_register_notify - register a notifier callback whenever a usb change happens
   * @nb: pointer to the notifier block for the callback events.
   *
   * These changes are either USB devices or busses being added or removed.
   */
  void usb_register_notify(struct notifier_block *nb)
  {
  	blocking_notifier_chain_register(&usb_notifier_list, nb);
  }
  EXPORT_SYMBOL_GPL(usb_register_notify);
  
  /**
   * usb_unregister_notify - unregister a notifier callback
   * @nb: pointer to the notifier block for the callback events.
   *
   * usb_register_notify() must have been previously called for this function
   * to work properly.
   */
  void usb_unregister_notify(struct notifier_block *nb)
  {
  	blocking_notifier_chain_unregister(&usb_notifier_list, nb);
  }
  EXPORT_SYMBOL_GPL(usb_unregister_notify);
  
  
  void usb_notify_add_device(struct usb_device *udev)
  {
  	blocking_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
  }
  
  void usb_notify_remove_device(struct usb_device *udev)
  {
  	/* Protect against simultaneous usbfs open */
  	mutex_lock(&usbfs_mutex);
  	blocking_notifier_call_chain(&usb_notifier_list,
  			USB_DEVICE_REMOVE, udev);
  	mutex_unlock(&usbfs_mutex);
  }
  
  void usb_notify_add_bus(struct usb_bus *ubus)
  {
  	blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
  }
  
  void usb_notify_remove_bus(struct usb_bus *ubus)
  {
  	blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
  }