1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
/*
* Linux network device link state notification
*
* Author:
* Stefan Rompf <sux@loplof.de>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/if.h>
#include <net/sock.h>
#include <linux/rtnetlink.h>
#include <linux/jiffies.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/bitops.h>
#include <asm/types.h>
enum lw_bits {
LW_RUNNING = 0,
LW_SE_USED
};
static unsigned long linkwatch_flags;
static unsigned long linkwatch_nextevent;
static void linkwatch_event(void *dummy);
static DECLARE_WORK(linkwatch_work, linkwatch_event, NULL);
static LIST_HEAD(lweventlist);
static DEFINE_SPINLOCK(lweventlist_lock);
struct lw_event {
struct list_head list;
struct net_device *dev;
};
/* Avoid kmalloc() for most systems */
static struct lw_event singleevent;
/* Must be called with the rtnl semaphore held */
void linkwatch_run_queue(void)
{
LIST_HEAD(head);
struct list_head *n, *next;
spin_lock_irq(&lweventlist_lock);
list_splice_init(&lweventlist, &head);
spin_unlock_irq(&lweventlist_lock);
list_for_each_safe(n, next, &head) {
struct lw_event *event = list_entry(n, struct lw_event, list);
struct net_device *dev = event->dev;
if (event == &singleevent) {
clear_bit(LW_SE_USED, &linkwatch_flags);
} else {
kfree(event);
}
/* We are about to handle this device,
* so new events can be accepted
*/
clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
if (dev->flags & IFF_UP) {
netdev_state_change(dev);
}
dev_put(dev);
}
}
static void linkwatch_event(void *dummy)
{
/* Limit the number of linkwatch events to one
* per second so that a runaway driver does not
* cause a storm of messages on the netlink
* socket
*/
linkwatch_nextevent = jiffies + HZ;
clear_bit(LW_RUNNING, &linkwatch_flags);
rtnl_shlock();
linkwatch_run_queue();
rtnl_shunlock();
}
void linkwatch_fire_event(struct net_device *dev)
{
if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {
unsigned long flags;
struct lw_event *event;
if (test_and_set_bit(LW_SE_USED, &linkwatch_flags)) {
event = kmalloc(sizeof(struct lw_event), GFP_ATOMIC);
if (unlikely(event == NULL)) {
clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
return;
}
} else {
event = &singleevent;
}
dev_hold(dev);
event->dev = dev;
spin_lock_irqsave(&lweventlist_lock, flags);
list_add_tail(&event->list, &lweventlist);
spin_unlock_irqrestore(&lweventlist_lock, flags);
if (!test_and_set_bit(LW_RUNNING, &linkwatch_flags)) {
unsigned long thisevent = jiffies;
if (thisevent >= linkwatch_nextevent) {
schedule_work(&linkwatch_work);
} else {
schedule_delayed_work(&linkwatch_work, linkwatch_nextevent - thisevent);
}
}
}
}
EXPORT_SYMBOL(linkwatch_fire_event);
|
