Linux kernel mirror (for testing)
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linux
1/* net/atm/ipcommon.c - Common items for all ways of doing IP over ATM */
2
3/* Written 1996-2000 by Werner Almesberger, EPFL LRC/ICA */
4
5
6#include <linux/module.h>
7#include <linux/string.h>
8#include <linux/skbuff.h>
9#include <linux/netdevice.h>
10#include <linux/in.h>
11#include <linux/atmdev.h>
12#include <linux/atmclip.h>
13
14#include "common.h"
15#include "ipcommon.h"
16
17
18#if 0
19#define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
20#else
21#define DPRINTK(format,args...)
22#endif
23
24
25/*
26 * skb_migrate appends the list at "from" to "to", emptying "from" in the
27 * process. skb_migrate is atomic with respect to all other skb operations on
28 * "from" and "to". Note that it locks both lists at the same time, so to deal
29 * with the lock ordering, the locks are taken in address order.
30 *
31 * This function should live in skbuff.c or skbuff.h.
32 */
33
34
35void skb_migrate(struct sk_buff_head *from, struct sk_buff_head *to)
36{
37 unsigned long flags;
38 struct sk_buff *skb_from = (struct sk_buff *) from;
39 struct sk_buff *skb_to = (struct sk_buff *) to;
40 struct sk_buff *prev;
41
42 if ((unsigned long) from < (unsigned long) to) {
43 spin_lock_irqsave(&from->lock, flags);
44 spin_lock_nested(&to->lock, SINGLE_DEPTH_NESTING);
45 } else {
46 spin_lock_irqsave(&to->lock, flags);
47 spin_lock_nested(&from->lock, SINGLE_DEPTH_NESTING);
48 }
49 prev = from->prev;
50 from->next->prev = to->prev;
51 prev->next = skb_to;
52 to->prev->next = from->next;
53 to->prev = from->prev;
54 to->qlen += from->qlen;
55 spin_unlock(&to->lock);
56 from->prev = skb_from;
57 from->next = skb_from;
58 from->qlen = 0;
59 spin_unlock_irqrestore(&from->lock, flags);
60}
61
62
63EXPORT_SYMBOL(skb_migrate);