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_notify() 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 } 69