Merge branch 'rio.b19' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/bird
[linux-2.6] / net / core / netpoll.c
1 /*
2  * Common framework for low-level network console, dump, and debugger code
3  *
4  * Sep 8 2003  Matt Mackall <mpm@selenic.com>
5  *
6  * based on the netconsole code from:
7  *
8  * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
9  * Copyright (C) 2002  Red Hat, Inc.
10  */
11
12 #include <linux/smp_lock.h>
13 #include <linux/netdevice.h>
14 #include <linux/etherdevice.h>
15 #include <linux/string.h>
16 #include <linux/if_arp.h>
17 #include <linux/inetdevice.h>
18 #include <linux/inet.h>
19 #include <linux/interrupt.h>
20 #include <linux/netpoll.h>
21 #include <linux/sched.h>
22 #include <linux/delay.h>
23 #include <linux/rcupdate.h>
24 #include <linux/workqueue.h>
25 #include <net/tcp.h>
26 #include <net/udp.h>
27 #include <asm/unaligned.h>
28
29 /*
30  * We maintain a small pool of fully-sized skbs, to make sure the
31  * message gets out even in extreme OOM situations.
32  */
33
34 #define MAX_UDP_CHUNK 1460
35 #define MAX_SKBS 32
36 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
37 #define MAX_RETRIES 20000
38
39 static DEFINE_SPINLOCK(skb_list_lock);
40 static int nr_skbs;
41 static struct sk_buff *skbs;
42
43 static DEFINE_SPINLOCK(queue_lock);
44 static int queue_depth;
45 static struct sk_buff *queue_head, *queue_tail;
46
47 static atomic_t trapped;
48
49 #define NETPOLL_RX_ENABLED  1
50 #define NETPOLL_RX_DROP     2
51
52 #define MAX_SKB_SIZE \
53                 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
54                                 sizeof(struct iphdr) + sizeof(struct ethhdr))
55
56 static void zap_completion_queue(void);
57
58 static void queue_process(void *p)
59 {
60         unsigned long flags;
61         struct sk_buff *skb;
62
63         while (queue_head) {
64                 spin_lock_irqsave(&queue_lock, flags);
65
66                 skb = queue_head;
67                 queue_head = skb->next;
68                 if (skb == queue_tail)
69                         queue_head = NULL;
70
71                 queue_depth--;
72
73                 spin_unlock_irqrestore(&queue_lock, flags);
74
75                 dev_queue_xmit(skb);
76         }
77 }
78
79 static DECLARE_WORK(send_queue, queue_process, NULL);
80
81 void netpoll_queue(struct sk_buff *skb)
82 {
83         unsigned long flags;
84
85         if (queue_depth == MAX_QUEUE_DEPTH) {
86                 __kfree_skb(skb);
87                 return;
88         }
89
90         spin_lock_irqsave(&queue_lock, flags);
91         if (!queue_head)
92                 queue_head = skb;
93         else
94                 queue_tail->next = skb;
95         queue_tail = skb;
96         queue_depth++;
97         spin_unlock_irqrestore(&queue_lock, flags);
98
99         schedule_work(&send_queue);
100 }
101
102 static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
103                              unsigned short ulen, u32 saddr, u32 daddr)
104 {
105         unsigned int psum;
106
107         if (uh->check == 0 || skb->ip_summed == CHECKSUM_UNNECESSARY)
108                 return 0;
109
110         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
111
112         if (skb->ip_summed == CHECKSUM_HW &&
113             !(u16)csum_fold(csum_add(psum, skb->csum)))
114                 return 0;
115
116         skb->csum = psum;
117
118         return __skb_checksum_complete(skb);
119 }
120
121 /*
122  * Check whether delayed processing was scheduled for our NIC. If so,
123  * we attempt to grab the poll lock and use ->poll() to pump the card.
124  * If this fails, either we've recursed in ->poll() or it's already
125  * running on another CPU.
126  *
127  * Note: we don't mask interrupts with this lock because we're using
128  * trylock here and interrupts are already disabled in the softirq
129  * case. Further, we test the poll_owner to avoid recursion on UP
130  * systems where the lock doesn't exist.
131  *
132  * In cases where there is bi-directional communications, reading only
133  * one message at a time can lead to packets being dropped by the
134  * network adapter, forcing superfluous retries and possibly timeouts.
135  * Thus, we set our budget to greater than 1.
136  */
137 static void poll_napi(struct netpoll *np)
138 {
139         struct netpoll_info *npinfo = np->dev->npinfo;
140         int budget = 16;
141
142         if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
143             npinfo->poll_owner != smp_processor_id() &&
144             spin_trylock(&npinfo->poll_lock)) {
145                 npinfo->rx_flags |= NETPOLL_RX_DROP;
146                 atomic_inc(&trapped);
147
148                 np->dev->poll(np->dev, &budget);
149
150                 atomic_dec(&trapped);
151                 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
152                 spin_unlock(&npinfo->poll_lock);
153         }
154 }
155
156 void netpoll_poll(struct netpoll *np)
157 {
158         if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
159                 return;
160
161         /* Process pending work on NIC */
162         np->dev->poll_controller(np->dev);
163         if (np->dev->poll)
164                 poll_napi(np);
165
166         zap_completion_queue();
167 }
168
169 static void refill_skbs(void)
170 {
171         struct sk_buff *skb;
172         unsigned long flags;
173
174         spin_lock_irqsave(&skb_list_lock, flags);
175         while (nr_skbs < MAX_SKBS) {
176                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
177                 if (!skb)
178                         break;
179
180                 skb->next = skbs;
181                 skbs = skb;
182                 nr_skbs++;
183         }
184         spin_unlock_irqrestore(&skb_list_lock, flags);
185 }
186
187 static void zap_completion_queue(void)
188 {
189         unsigned long flags;
190         struct softnet_data *sd = &get_cpu_var(softnet_data);
191
192         if (sd->completion_queue) {
193                 struct sk_buff *clist;
194
195                 local_irq_save(flags);
196                 clist = sd->completion_queue;
197                 sd->completion_queue = NULL;
198                 local_irq_restore(flags);
199
200                 while (clist != NULL) {
201                         struct sk_buff *skb = clist;
202                         clist = clist->next;
203                         if(skb->destructor)
204                                 dev_kfree_skb_any(skb); /* put this one back */
205                         else
206                                 __kfree_skb(skb);
207                 }
208         }
209
210         put_cpu_var(softnet_data);
211 }
212
213 static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve)
214 {
215         int once = 1, count = 0;
216         unsigned long flags;
217         struct sk_buff *skb = NULL;
218
219         zap_completion_queue();
220 repeat:
221         if (nr_skbs < MAX_SKBS)
222                 refill_skbs();
223
224         skb = alloc_skb(len, GFP_ATOMIC);
225
226         if (!skb) {
227                 spin_lock_irqsave(&skb_list_lock, flags);
228                 skb = skbs;
229                 if (skb) {
230                         skbs = skb->next;
231                         skb->next = NULL;
232                         nr_skbs--;
233                 }
234                 spin_unlock_irqrestore(&skb_list_lock, flags);
235         }
236
237         if(!skb) {
238                 count++;
239                 if (once && (count == 1000000)) {
240                         printk("out of netpoll skbs!\n");
241                         once = 0;
242                 }
243                 netpoll_poll(np);
244                 goto repeat;
245         }
246
247         atomic_set(&skb->users, 1);
248         skb_reserve(skb, reserve);
249         return skb;
250 }
251
252 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
253 {
254         int status;
255         struct netpoll_info *npinfo;
256
257         if (!np || !np->dev || !netif_running(np->dev)) {
258                 __kfree_skb(skb);
259                 return;
260         }
261
262         npinfo = np->dev->npinfo;
263
264         /* avoid recursion */
265         if (npinfo->poll_owner == smp_processor_id() ||
266             np->dev->xmit_lock_owner == smp_processor_id()) {
267                 if (np->drop)
268                         np->drop(skb);
269                 else
270                         __kfree_skb(skb);
271                 return;
272         }
273
274         do {
275                 npinfo->tries--;
276                 netif_tx_lock(np->dev);
277
278                 /*
279                  * network drivers do not expect to be called if the queue is
280                  * stopped.
281                  */
282                 if (netif_queue_stopped(np->dev)) {
283                         netif_tx_unlock(np->dev);
284                         netpoll_poll(np);
285                         udelay(50);
286                         continue;
287                 }
288
289                 status = np->dev->hard_start_xmit(skb, np->dev);
290                 netif_tx_unlock(np->dev);
291
292                 /* success */
293                 if(!status) {
294                         npinfo->tries = MAX_RETRIES; /* reset */
295                         return;
296                 }
297
298                 /* transmit busy */
299                 netpoll_poll(np);
300                 udelay(50);
301         } while (npinfo->tries > 0);
302 }
303
304 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
305 {
306         int total_len, eth_len, ip_len, udp_len;
307         struct sk_buff *skb;
308         struct udphdr *udph;
309         struct iphdr *iph;
310         struct ethhdr *eth;
311
312         udp_len = len + sizeof(*udph);
313         ip_len = eth_len = udp_len + sizeof(*iph);
314         total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
315
316         skb = find_skb(np, total_len, total_len - len);
317         if (!skb)
318                 return;
319
320         memcpy(skb->data, msg, len);
321         skb->len += len;
322
323         udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
324         udph->source = htons(np->local_port);
325         udph->dest = htons(np->remote_port);
326         udph->len = htons(udp_len);
327         udph->check = 0;
328
329         iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
330
331         /* iph->version = 4; iph->ihl = 5; */
332         put_unaligned(0x45, (unsigned char *)iph);
333         iph->tos      = 0;
334         put_unaligned(htons(ip_len), &(iph->tot_len));
335         iph->id       = 0;
336         iph->frag_off = 0;
337         iph->ttl      = 64;
338         iph->protocol = IPPROTO_UDP;
339         iph->check    = 0;
340         put_unaligned(htonl(np->local_ip), &(iph->saddr));
341         put_unaligned(htonl(np->remote_ip), &(iph->daddr));
342         iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
343
344         eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
345
346         eth->h_proto = htons(ETH_P_IP);
347         memcpy(eth->h_source, np->local_mac, 6);
348         memcpy(eth->h_dest, np->remote_mac, 6);
349
350         skb->dev = np->dev;
351
352         netpoll_send_skb(np, skb);
353 }
354
355 static void arp_reply(struct sk_buff *skb)
356 {
357         struct netpoll_info *npinfo = skb->dev->npinfo;
358         struct arphdr *arp;
359         unsigned char *arp_ptr;
360         int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
361         u32 sip, tip;
362         struct sk_buff *send_skb;
363         struct netpoll *np = NULL;
364
365         if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
366                 np = npinfo->rx_np;
367         if (!np)
368                 return;
369
370         /* No arp on this interface */
371         if (skb->dev->flags & IFF_NOARP)
372                 return;
373
374         if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
375                                  (2 * skb->dev->addr_len) +
376                                  (2 * sizeof(u32)))))
377                 return;
378
379         skb->h.raw = skb->nh.raw = skb->data;
380         arp = skb->nh.arph;
381
382         if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
383              arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
384             arp->ar_pro != htons(ETH_P_IP) ||
385             arp->ar_op != htons(ARPOP_REQUEST))
386                 return;
387
388         arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
389         memcpy(&sip, arp_ptr, 4);
390         arp_ptr += 4 + skb->dev->addr_len;
391         memcpy(&tip, arp_ptr, 4);
392
393         /* Should we ignore arp? */
394         if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
395                 return;
396
397         size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
398         send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
399                             LL_RESERVED_SPACE(np->dev));
400
401         if (!send_skb)
402                 return;
403
404         send_skb->nh.raw = send_skb->data;
405         arp = (struct arphdr *) skb_put(send_skb, size);
406         send_skb->dev = skb->dev;
407         send_skb->protocol = htons(ETH_P_ARP);
408
409         /* Fill the device header for the ARP frame */
410
411         if (np->dev->hard_header &&
412             np->dev->hard_header(send_skb, skb->dev, ptype,
413                                        np->remote_mac, np->local_mac,
414                                        send_skb->len) < 0) {
415                 kfree_skb(send_skb);
416                 return;
417         }
418
419         /*
420          * Fill out the arp protocol part.
421          *
422          * we only support ethernet device type,
423          * which (according to RFC 1390) should always equal 1 (Ethernet).
424          */
425
426         arp->ar_hrd = htons(np->dev->type);
427         arp->ar_pro = htons(ETH_P_IP);
428         arp->ar_hln = np->dev->addr_len;
429         arp->ar_pln = 4;
430         arp->ar_op = htons(type);
431
432         arp_ptr=(unsigned char *)(arp + 1);
433         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
434         arp_ptr += np->dev->addr_len;
435         memcpy(arp_ptr, &tip, 4);
436         arp_ptr += 4;
437         memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
438         arp_ptr += np->dev->addr_len;
439         memcpy(arp_ptr, &sip, 4);
440
441         netpoll_send_skb(np, send_skb);
442 }
443
444 int __netpoll_rx(struct sk_buff *skb)
445 {
446         int proto, len, ulen;
447         struct iphdr *iph;
448         struct udphdr *uh;
449         struct netpoll *np = skb->dev->npinfo->rx_np;
450
451         if (!np)
452                 goto out;
453         if (skb->dev->type != ARPHRD_ETHER)
454                 goto out;
455
456         /* check if netpoll clients need ARP */
457         if (skb->protocol == __constant_htons(ETH_P_ARP) &&
458             atomic_read(&trapped)) {
459                 arp_reply(skb);
460                 return 1;
461         }
462
463         proto = ntohs(eth_hdr(skb)->h_proto);
464         if (proto != ETH_P_IP)
465                 goto out;
466         if (skb->pkt_type == PACKET_OTHERHOST)
467                 goto out;
468         if (skb_shared(skb))
469                 goto out;
470
471         iph = (struct iphdr *)skb->data;
472         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
473                 goto out;
474         if (iph->ihl < 5 || iph->version != 4)
475                 goto out;
476         if (!pskb_may_pull(skb, iph->ihl*4))
477                 goto out;
478         if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
479                 goto out;
480
481         len = ntohs(iph->tot_len);
482         if (skb->len < len || len < iph->ihl*4)
483                 goto out;
484
485         if (iph->protocol != IPPROTO_UDP)
486                 goto out;
487
488         len -= iph->ihl*4;
489         uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
490         ulen = ntohs(uh->len);
491
492         if (ulen != len)
493                 goto out;
494         if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
495                 goto out;
496         if (np->local_ip && np->local_ip != ntohl(iph->daddr))
497                 goto out;
498         if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
499                 goto out;
500         if (np->local_port && np->local_port != ntohs(uh->dest))
501                 goto out;
502
503         np->rx_hook(np, ntohs(uh->source),
504                     (char *)(uh+1),
505                     ulen - sizeof(struct udphdr));
506
507         kfree_skb(skb);
508         return 1;
509
510 out:
511         if (atomic_read(&trapped)) {
512                 kfree_skb(skb);
513                 return 1;
514         }
515
516         return 0;
517 }
518
519 int netpoll_parse_options(struct netpoll *np, char *opt)
520 {
521         char *cur=opt, *delim;
522
523         if(*cur != '@') {
524                 if ((delim = strchr(cur, '@')) == NULL)
525                         goto parse_failed;
526                 *delim=0;
527                 np->local_port=simple_strtol(cur, NULL, 10);
528                 cur=delim;
529         }
530         cur++;
531         printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
532
533         if(*cur != '/') {
534                 if ((delim = strchr(cur, '/')) == NULL)
535                         goto parse_failed;
536                 *delim=0;
537                 np->local_ip=ntohl(in_aton(cur));
538                 cur=delim;
539
540                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
541                        np->name, HIPQUAD(np->local_ip));
542         }
543         cur++;
544
545         if ( *cur != ',') {
546                 /* parse out dev name */
547                 if ((delim = strchr(cur, ',')) == NULL)
548                         goto parse_failed;
549                 *delim=0;
550                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
551                 cur=delim;
552         }
553         cur++;
554
555         printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
556
557         if ( *cur != '@' ) {
558                 /* dst port */
559                 if ((delim = strchr(cur, '@')) == NULL)
560                         goto parse_failed;
561                 *delim=0;
562                 np->remote_port=simple_strtol(cur, NULL, 10);
563                 cur=delim;
564         }
565         cur++;
566         printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
567
568         /* dst ip */
569         if ((delim = strchr(cur, '/')) == NULL)
570                 goto parse_failed;
571         *delim=0;
572         np->remote_ip=ntohl(in_aton(cur));
573         cur=delim+1;
574
575         printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
576                        np->name, HIPQUAD(np->remote_ip));
577
578         if( *cur != 0 )
579         {
580                 /* MAC address */
581                 if ((delim = strchr(cur, ':')) == NULL)
582                         goto parse_failed;
583                 *delim=0;
584                 np->remote_mac[0]=simple_strtol(cur, NULL, 16);
585                 cur=delim+1;
586                 if ((delim = strchr(cur, ':')) == NULL)
587                         goto parse_failed;
588                 *delim=0;
589                 np->remote_mac[1]=simple_strtol(cur, NULL, 16);
590                 cur=delim+1;
591                 if ((delim = strchr(cur, ':')) == NULL)
592                         goto parse_failed;
593                 *delim=0;
594                 np->remote_mac[2]=simple_strtol(cur, NULL, 16);
595                 cur=delim+1;
596                 if ((delim = strchr(cur, ':')) == NULL)
597                         goto parse_failed;
598                 *delim=0;
599                 np->remote_mac[3]=simple_strtol(cur, NULL, 16);
600                 cur=delim+1;
601                 if ((delim = strchr(cur, ':')) == NULL)
602                         goto parse_failed;
603                 *delim=0;
604                 np->remote_mac[4]=simple_strtol(cur, NULL, 16);
605                 cur=delim+1;
606                 np->remote_mac[5]=simple_strtol(cur, NULL, 16);
607         }
608
609         printk(KERN_INFO "%s: remote ethernet address "
610                "%02x:%02x:%02x:%02x:%02x:%02x\n",
611                np->name,
612                np->remote_mac[0],
613                np->remote_mac[1],
614                np->remote_mac[2],
615                np->remote_mac[3],
616                np->remote_mac[4],
617                np->remote_mac[5]);
618
619         return 0;
620
621  parse_failed:
622         printk(KERN_INFO "%s: couldn't parse config at %s!\n",
623                np->name, cur);
624         return -1;
625 }
626
627 int netpoll_setup(struct netpoll *np)
628 {
629         struct net_device *ndev = NULL;
630         struct in_device *in_dev;
631         struct netpoll_info *npinfo;
632         unsigned long flags;
633
634         if (np->dev_name)
635                 ndev = dev_get_by_name(np->dev_name);
636         if (!ndev) {
637                 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
638                        np->name, np->dev_name);
639                 return -1;
640         }
641
642         np->dev = ndev;
643         if (!ndev->npinfo) {
644                 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
645                 if (!npinfo)
646                         goto release;
647
648                 npinfo->rx_flags = 0;
649                 npinfo->rx_np = NULL;
650                 spin_lock_init(&npinfo->poll_lock);
651                 npinfo->poll_owner = -1;
652                 npinfo->tries = MAX_RETRIES;
653                 spin_lock_init(&npinfo->rx_lock);
654         } else
655                 npinfo = ndev->npinfo;
656
657         if (!ndev->poll_controller) {
658                 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
659                        np->name, np->dev_name);
660                 goto release;
661         }
662
663         if (!netif_running(ndev)) {
664                 unsigned long atmost, atleast;
665
666                 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
667                        np->name, np->dev_name);
668
669                 rtnl_lock();
670                 if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
671                         printk(KERN_ERR "%s: failed to open %s\n",
672                                np->name, np->dev_name);
673                         rtnl_unlock();
674                         goto release;
675                 }
676                 rtnl_unlock();
677
678                 atleast = jiffies + HZ/10;
679                 atmost = jiffies + 4*HZ;
680                 while (!netif_carrier_ok(ndev)) {
681                         if (time_after(jiffies, atmost)) {
682                                 printk(KERN_NOTICE
683                                        "%s: timeout waiting for carrier\n",
684                                        np->name);
685                                 break;
686                         }
687                         cond_resched();
688                 }
689
690                 /* If carrier appears to come up instantly, we don't
691                  * trust it and pause so that we don't pump all our
692                  * queued console messages into the bitbucket.
693                  */
694
695                 if (time_before(jiffies, atleast)) {
696                         printk(KERN_NOTICE "%s: carrier detect appears"
697                                " untrustworthy, waiting 4 seconds\n",
698                                np->name);
699                         msleep(4000);
700                 }
701         }
702
703         if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
704                 memcpy(np->local_mac, ndev->dev_addr, 6);
705
706         if (!np->local_ip) {
707                 rcu_read_lock();
708                 in_dev = __in_dev_get_rcu(ndev);
709
710                 if (!in_dev || !in_dev->ifa_list) {
711                         rcu_read_unlock();
712                         printk(KERN_ERR "%s: no IP address for %s, aborting\n",
713                                np->name, np->dev_name);
714                         goto release;
715                 }
716
717                 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
718                 rcu_read_unlock();
719                 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
720                        np->name, HIPQUAD(np->local_ip));
721         }
722
723         if (np->rx_hook) {
724                 spin_lock_irqsave(&npinfo->rx_lock, flags);
725                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
726                 npinfo->rx_np = np;
727                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
728         }
729
730         /* fill up the skb queue */
731         refill_skbs();
732
733         /* last thing to do is link it to the net device structure */
734         ndev->npinfo = npinfo;
735
736         /* avoid racing with NAPI reading npinfo */
737         synchronize_rcu();
738
739         return 0;
740
741  release:
742         if (!ndev->npinfo)
743                 kfree(npinfo);
744         np->dev = NULL;
745         dev_put(ndev);
746         return -1;
747 }
748
749 void netpoll_cleanup(struct netpoll *np)
750 {
751         struct netpoll_info *npinfo;
752         unsigned long flags;
753
754         if (np->dev) {
755                 npinfo = np->dev->npinfo;
756                 if (npinfo && npinfo->rx_np == np) {
757                         spin_lock_irqsave(&npinfo->rx_lock, flags);
758                         npinfo->rx_np = NULL;
759                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
760                         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
761                 }
762                 dev_put(np->dev);
763         }
764
765         np->dev = NULL;
766 }
767
768 int netpoll_trap(void)
769 {
770         return atomic_read(&trapped);
771 }
772
773 void netpoll_set_trap(int trap)
774 {
775         if (trap)
776                 atomic_inc(&trapped);
777         else
778                 atomic_dec(&trapped);
779 }
780
781 EXPORT_SYMBOL(netpoll_set_trap);
782 EXPORT_SYMBOL(netpoll_trap);
783 EXPORT_SYMBOL(netpoll_parse_options);
784 EXPORT_SYMBOL(netpoll_setup);
785 EXPORT_SYMBOL(netpoll_cleanup);
786 EXPORT_SYMBOL(netpoll_send_udp);
787 EXPORT_SYMBOL(netpoll_poll);
788 EXPORT_SYMBOL(netpoll_queue);