tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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/config.h>
13#include <linux/kernel.h>
14#include <linux/notifier.h>
15#include <linux/usb.h>
16#include "usb.h"
17
18
19static struct notifier_block *usb_notifier_list;
20static DECLARE_MUTEX(usb_notifier_lock);
21
22static void usb_notifier_chain_register(struct notifier_block **list,
23 struct notifier_block *n)
24{
25 down(&usb_notifier_lock);
26 while (*list) {
27 if (n->priority > (*list)->priority)
28 break;
29 list = &((*list)->next);
30 }
31 n->next = *list;
32 *list = n;
33 up(&usb_notifier_lock);
34}
35
36static void usb_notifier_chain_unregister(struct notifier_block **nl,
37 struct notifier_block *n)
38{
39 down(&usb_notifier_lock);
40 while ((*nl)!=NULL) {
41 if ((*nl)==n) {
42 *nl = n->next;
43 goto exit;
44 }
45 nl=&((*nl)->next);
46 }
47exit:
48 up(&usb_notifier_lock);
49}
50
51static int usb_notifier_call_chain(struct notifier_block **n,
52 unsigned long val, void *v)
53{
54 int ret=NOTIFY_DONE;
55 struct notifier_block *nb = *n;
56
57 down(&usb_notifier_lock);
58 while (nb) {
59 ret = nb->notifier_call(nb,val,v);
60 if (ret&NOTIFY_STOP_MASK) {
61 goto exit;
62 }
63 nb = nb->next;
64 }
65exit:
66 up(&usb_notifier_lock);
67 return ret;
68}
69
70/**
71 * usb_register_notify - register a notifier callback whenever a usb change happens
72 * @nb: pointer to the notifier block for the callback events.
73 *
74 * These changes are either USB devices or busses being added or removed.
75 */
76void usb_register_notify(struct notifier_block *nb)
77{
78 usb_notifier_chain_register(&usb_notifier_list, nb);
79}
80EXPORT_SYMBOL_GPL(usb_register_notify);
81
82/**
83 * usb_unregister_notify - unregister a notifier callback
84 * @nb: pointer to the notifier block for the callback events.
85 *
86 * usb_register_notifier() must have been previously called for this function
87 * to work properly.
88 */
89void usb_unregister_notify(struct notifier_block *nb)
90{
91 usb_notifier_chain_unregister(&usb_notifier_list, nb);
92}
93EXPORT_SYMBOL_GPL(usb_unregister_notify);
94
95
96void usb_notify_add_device(struct usb_device *udev)
97{
98 usb_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
99}
100
101void usb_notify_remove_device(struct usb_device *udev)
102{
103 usb_notifier_call_chain(&usb_notifier_list, USB_DEVICE_REMOVE, udev);
104}
105
106void usb_notify_add_bus(struct usb_bus *ubus)
107{
108 usb_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
109}
110
111void usb_notify_remove_bus(struct usb_bus *ubus)
112{
113 usb_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
114}