notify.c 1.7 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * All the USB notify logic
  4. *
  5. * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
  6. *
  7. * notifier functions originally based on those in kernel/sys.c
  8. * but fixed up to not be so broken.
  9. *
  10. * Released under the GPLv2 only.
  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. static BLOCKING_NOTIFIER_HEAD(usb_notifier_list);
  19. /**
  20. * usb_register_notify - register a notifier callback whenever a usb change happens
  21. * @nb: pointer to the notifier block for the callback events.
  22. *
  23. * These changes are either USB devices or busses being added or removed.
  24. */
  25. void usb_register_notify(struct notifier_block *nb)
  26. {
  27. blocking_notifier_chain_register(&usb_notifier_list, nb);
  28. }
  29. EXPORT_SYMBOL_GPL(usb_register_notify);
  30. /**
  31. * usb_unregister_notify - unregister a notifier callback
  32. * @nb: pointer to the notifier block for the callback events.
  33. *
  34. * usb_register_notify() must have been previously called for this function
  35. * to work properly.
  36. */
  37. void usb_unregister_notify(struct notifier_block *nb)
  38. {
  39. blocking_notifier_chain_unregister(&usb_notifier_list, nb);
  40. }
  41. EXPORT_SYMBOL_GPL(usb_unregister_notify);
  42. void usb_notify_add_device(struct usb_device *udev)
  43. {
  44. blocking_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
  45. }
  46. void usb_notify_remove_device(struct usb_device *udev)
  47. {
  48. blocking_notifier_call_chain(&usb_notifier_list,
  49. USB_DEVICE_REMOVE, udev);
  50. }
  51. void usb_notify_add_bus(struct usb_bus *ubus)
  52. {
  53. blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
  54. }
  55. void usb_notify_remove_bus(struct usb_bus *ubus)
  56. {
  57. blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
  58. }