1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
138 lines
3.1 KiB
C
138 lines
3.1 KiB
C
/*
|
|
* 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);
|