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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/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);
}
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