/* * 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/config.h> #include <linux/kernel.h> #include <linux/notifier.h> #include <linux/usb.h> #include "usb.h" static struct notifier_block *usb_notifier_list; static DECLARE_MUTEX(usb_notifier_lock); static void usb_notifier_chain_register(struct notifier_block **list, struct notifier_block *n) { down(&usb_notifier_lock); while (*list) { if (n->priority > (*list)->priority) break; list = &((*list)->next); } n->next = *list; *list = n; up(&usb_notifier_lock); } static void usb_notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n) { down(&usb_notifier_lock); while ((*nl)!=NULL) { if ((*nl)==n) { *nl = n->next; goto exit; } nl=&((*nl)->next); } exit: up(&usb_notifier_lock); } static int usb_notifier_call_chain(struct notifier_block **n, unsigned long val, void *v) { int ret=NOTIFY_DONE; struct notifier_block *nb = *n; down(&usb_notifier_lock); while (nb) { ret = nb->notifier_call(nb,val,v); if (ret&NOTIFY_STOP_MASK) { goto exit; } nb = nb->next; } exit: up(&usb_notifier_lock); return ret; } /** * 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) { usb_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_notifier() must have been previously called for this function * to work properly. */ void usb_unregister_notify(struct notifier_block *nb) { usb_notifier_chain_unregister(&usb_notifier_list, nb); } EXPORT_SYMBOL_GPL(usb_unregister_notify); void usb_notify_add_device(struct usb_device *udev) { usb_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev); } void usb_notify_remove_device(struct usb_device *udev) { usb_notifier_call_chain(&usb_notifier_list, USB_DEVICE_REMOVE, udev); } void usb_notify_add_bus(struct usb_bus *ubus) { usb_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus); } void usb_notify_remove_bus(struct usb_bus *ubus) { usb_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus); }