[NET]: cleanup extra semicolons
[linux-2.6.git] / net / core / link_watch.c
1 /*
2  * Linux network device link state notification
3  *
4  * Author:
5  *     Stefan Rompf <sux@loplof.de>
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License
9  * as published by the Free Software Foundation; either version
10  * 2 of the License, or (at your option) any later version.
11  *
12  */
13
14 #include <linux/module.h>
15 #include <linux/netdevice.h>
16 #include <linux/if.h>
17 #include <net/sock.h>
18 #include <net/pkt_sched.h>
19 #include <linux/rtnetlink.h>
20 #include <linux/jiffies.h>
21 #include <linux/spinlock.h>
22 #include <linux/list.h>
23 #include <linux/slab.h>
24 #include <linux/workqueue.h>
25 #include <linux/bitops.h>
26 #include <asm/types.h>
27
28
29 enum lw_bits {
30         LW_RUNNING = 0,
31         LW_SE_USED
32 };
33
34 static unsigned long linkwatch_flags;
35 static unsigned long linkwatch_nextevent;
36
37 static void linkwatch_event(struct work_struct *dummy);
38 static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event);
39
40 static LIST_HEAD(lweventlist);
41 static DEFINE_SPINLOCK(lweventlist_lock);
42
43 struct lw_event {
44         struct list_head list;
45         struct net_device *dev;
46 };
47
48 /* Avoid kmalloc() for most systems */
49 static struct lw_event singleevent;
50
51 static unsigned char default_operstate(const struct net_device *dev)
52 {
53         if (!netif_carrier_ok(dev))
54                 return (dev->ifindex != dev->iflink ?
55                         IF_OPER_LOWERLAYERDOWN : IF_OPER_DOWN);
56
57         if (netif_dormant(dev))
58                 return IF_OPER_DORMANT;
59
60         return IF_OPER_UP;
61 }
62
63
64 static void rfc2863_policy(struct net_device *dev)
65 {
66         unsigned char operstate = default_operstate(dev);
67
68         if (operstate == dev->operstate)
69                 return;
70
71         write_lock_bh(&dev_base_lock);
72
73         switch(dev->link_mode) {
74         case IF_LINK_MODE_DORMANT:
75                 if (operstate == IF_OPER_UP)
76                         operstate = IF_OPER_DORMANT;
77                 break;
78
79         case IF_LINK_MODE_DEFAULT:
80         default:
81                 break;
82         }
83
84         dev->operstate = operstate;
85
86         write_unlock_bh(&dev_base_lock);
87 }
88
89
90 /* Must be called with the rtnl semaphore held */
91 void linkwatch_run_queue(void)
92 {
93         struct list_head head, *n, *next;
94
95         spin_lock_irq(&lweventlist_lock);
96         list_replace_init(&lweventlist, &head);
97         spin_unlock_irq(&lweventlist_lock);
98
99         list_for_each_safe(n, next, &head) {
100                 struct lw_event *event = list_entry(n, struct lw_event, list);
101                 struct net_device *dev = event->dev;
102
103                 if (event == &singleevent) {
104                         clear_bit(LW_SE_USED, &linkwatch_flags);
105                 } else {
106                         kfree(event);
107                 }
108
109                 /* We are about to handle this device,
110                  * so new events can be accepted
111                  */
112                 clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
113
114                 rfc2863_policy(dev);
115                 if (dev->flags & IFF_UP) {
116                         if (netif_carrier_ok(dev)) {
117                                 WARN_ON(dev->qdisc_sleeping == &noop_qdisc);
118                                 dev_activate(dev);
119                         } else
120                                 dev_deactivate(dev);
121
122                         netdev_state_change(dev);
123                 }
124
125                 dev_put(dev);
126         }
127 }
128
129
130 static void linkwatch_event(struct work_struct *dummy)
131 {
132         /* Limit the number of linkwatch events to one
133          * per second so that a runaway driver does not
134          * cause a storm of messages on the netlink
135          * socket
136          */
137         linkwatch_nextevent = jiffies + HZ;
138         clear_bit(LW_RUNNING, &linkwatch_flags);
139
140         rtnl_lock();
141         linkwatch_run_queue();
142         rtnl_unlock();
143 }
144
145
146 void linkwatch_fire_event(struct net_device *dev)
147 {
148         if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {
149                 unsigned long flags;
150                 struct lw_event *event;
151
152                 if (test_and_set_bit(LW_SE_USED, &linkwatch_flags)) {
153                         event = kmalloc(sizeof(struct lw_event), GFP_ATOMIC);
154
155                         if (unlikely(event == NULL)) {
156                                 clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
157                                 return;
158                         }
159                 } else {
160                         event = &singleevent;
161                 }
162
163                 dev_hold(dev);
164                 event->dev = dev;
165
166                 spin_lock_irqsave(&lweventlist_lock, flags);
167                 list_add_tail(&event->list, &lweventlist);
168                 spin_unlock_irqrestore(&lweventlist_lock, flags);
169
170                 if (!test_and_set_bit(LW_RUNNING, &linkwatch_flags)) {
171                         unsigned long delay = linkwatch_nextevent - jiffies;
172
173                         /* If we wrap around we'll delay it by at most HZ. */
174                         if (delay > HZ)
175                                 delay = 0;
176                         schedule_delayed_work(&linkwatch_work, delay);
177                 }
178         }
179 }
180
181 EXPORT_SYMBOL(linkwatch_fire_event);