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mm owner: fix race between swapoff and exit
[linux-2.6/next.git] / net / core / netpoll.c
blob6c7af390be0a515cfb1d09d2db79f16776e0dbe4
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/netdevice.h>
13 #include <linux/etherdevice.h>
14 #include <linux/string.h>
15 #include <linux/if_arp.h>
16 #include <linux/inetdevice.h>
17 #include <linux/inet.h>
18 #include <linux/interrupt.h>
19 #include <linux/netpoll.h>
20 #include <linux/sched.h>
21 #include <linux/delay.h>
22 #include <linux/rcupdate.h>
23 #include <linux/workqueue.h>
24 #include <net/tcp.h>
25 #include <net/udp.h>
26 #include <asm/unaligned.h>
27
28 /*
29 * We maintain a small pool of fully-sized skbs, to make sure the
30 * message gets out even in extreme OOM situations.
31 */
32
33 #define MAX_UDP_CHUNK 1460
34 #define MAX_SKBS 32
35 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
36
37 static struct sk_buff_head skb_pool;
38
39 static atomic_t trapped;
40
41 #define USEC_PER_POLL 50
42 #define NETPOLL_RX_ENABLED 1
43 #define NETPOLL_RX_DROP 2
44
45 #define MAX_SKB_SIZE \
46 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
47 sizeof(struct iphdr) + sizeof(struct ethhdr))
48
49 static void zap_completion_queue(void);
50 static void arp_reply(struct sk_buff *skb);
51
52 static void queue_process(struct work_struct *work)
53 {
54 struct netpoll_info *npinfo =
55 container_of(work, struct netpoll_info, tx_work.work);
56 struct sk_buff *skb;
57 unsigned long flags;
58
59 while ((skb = skb_dequeue(&npinfo->txq))) {
60 struct net_device *dev = skb->dev;
61 struct netdev_queue *txq;
62
63 if (!netif_device_present(dev) || !netif_running(dev)) {
64 __kfree_skb(skb);
65 continue;
66 }
67
68 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
69
70 local_irq_save(flags);
71 __netif_tx_lock(txq, smp_processor_id());
72 if (netif_tx_queue_stopped(txq) ||
73 netif_tx_queue_frozen(txq) ||
74 dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
75 skb_queue_head(&npinfo->txq, skb);
76 __netif_tx_unlock(txq);
77 local_irq_restore(flags);
78
79 schedule_delayed_work(&npinfo->tx_work, HZ/10);
80 return;
81 }
82 __netif_tx_unlock(txq);
83 local_irq_restore(flags);
84 }
85 }
86
87 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
88 unsigned short ulen, __be32 saddr, __be32 daddr)
89 {
90 __wsum psum;
91
92 if (uh->check == 0 || skb_csum_unnecessary(skb))
93 return 0;
94
95 psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
96
97 if (skb->ip_summed == CHECKSUM_COMPLETE &&
98 !csum_fold(csum_add(psum, skb->csum)))
99 return 0;
100
101 skb->csum = psum;
102
103 return __skb_checksum_complete(skb);
104 }
105
106 /*
107 * Check whether delayed processing was scheduled for our NIC. If so,
108 * we attempt to grab the poll lock and use ->poll() to pump the card.
109 * If this fails, either we've recursed in ->poll() or it's already
110 * running on another CPU.
111 *
112 * Note: we don't mask interrupts with this lock because we're using
113 * trylock here and interrupts are already disabled in the softirq
114 * case. Further, we test the poll_owner to avoid recursion on UP
115 * systems where the lock doesn't exist.
116 *
117 * In cases where there is bi-directional communications, reading only
118 * one message at a time can lead to packets being dropped by the
119 * network adapter, forcing superfluous retries and possibly timeouts.
120 * Thus, we set our budget to greater than 1.
121 */
122 static int poll_one_napi(struct netpoll_info *npinfo,
123 struct napi_struct *napi, int budget)
124 {
125 int work;
126
127 /* net_rx_action's ->poll() invocations and our's are
128 * synchronized by this test which is only made while
129 * holding the napi->poll_lock.
130 */
131 if (!test_bit(NAPI_STATE_SCHED, &napi->state))
132 return budget;
133
134 npinfo->rx_flags |= NETPOLL_RX_DROP;
135 atomic_inc(&trapped);
136
137 work = napi->poll(napi, budget);
138
139 atomic_dec(&trapped);
140 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
141
142 return budget - work;
143 }
144
145 static void poll_napi(struct net_device *dev)
146 {
147 struct napi_struct *napi;
148 int budget = 16;
149
150 list_for_each_entry(napi, &dev->napi_list, dev_list) {
151 if (napi->poll_owner != smp_processor_id() &&
152 spin_trylock(&napi->poll_lock)) {
153 budget = poll_one_napi(dev->npinfo, napi, budget);
154 spin_unlock(&napi->poll_lock);
155
156 if (!budget)
157 break;
158 }
159 }
160 }
161
162 static void service_arp_queue(struct netpoll_info *npi)
163 {
164 if (npi) {
165 struct sk_buff *skb;
166
167 while ((skb = skb_dequeue(&npi->arp_tx)))
168 arp_reply(skb);
169 }
170 }
171
172 void netpoll_poll(struct netpoll *np)
173 {
174 struct net_device *dev = np->dev;
175
176 if (!dev || !netif_running(dev) || !dev->poll_controller)
177 return;
178
179 /* Process pending work on NIC */
180 dev->poll_controller(dev);
181
182 poll_napi(dev);
183
184 service_arp_queue(dev->npinfo);
185
186 zap_completion_queue();
187 }
188
189 static void refill_skbs(void)
190 {
191 struct sk_buff *skb;
192 unsigned long flags;
193
194 spin_lock_irqsave(&skb_pool.lock, flags);
195 while (skb_pool.qlen < MAX_SKBS) {
196 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
197 if (!skb)
198 break;
199
200 __skb_queue_tail(&skb_pool, skb);
201 }
202 spin_unlock_irqrestore(&skb_pool.lock, flags);
203 }
204
205 static void zap_completion_queue(void)
206 {
207 unsigned long flags;
208 struct softnet_data *sd = &get_cpu_var(softnet_data);
209
210 if (sd->completion_queue) {
211 struct sk_buff *clist;
212
213 local_irq_save(flags);
214 clist = sd->completion_queue;
215 sd->completion_queue = NULL;
216 local_irq_restore(flags);
217
218 while (clist != NULL) {
219 struct sk_buff *skb = clist;
220 clist = clist->next;
221 if (skb->destructor) {
222 atomic_inc(&skb->users);
223 dev_kfree_skb_any(skb); /* put this one back */
224 } else {
225 __kfree_skb(skb);
226 }
227 }
228 }
229
230 put_cpu_var(softnet_data);
231 }
232
233 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
234 {
235 int count = 0;
236 struct sk_buff *skb;
237
238 zap_completion_queue();
239 refill_skbs();
240 repeat:
241
242 skb = alloc_skb(len, GFP_ATOMIC);
243 if (!skb)
244 skb = skb_dequeue(&skb_pool);
245
246 if (!skb) {
247 if (++count < 10) {
248 netpoll_poll(np);
249 goto repeat;
250 }
251 return NULL;
252 }
253
254 atomic_set(&skb->users, 1);
255 skb_reserve(skb, reserve);
256 return skb;
257 }
258
259 static int netpoll_owner_active(struct net_device *dev)
260 {
261 struct napi_struct *napi;
262
263 list_for_each_entry(napi, &dev->napi_list, dev_list) {
264 if (napi->poll_owner == smp_processor_id())
265 return 1;
266 }
267 return 0;
268 }
269
270 static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
271 {
272 int status = NETDEV_TX_BUSY;
273 unsigned long tries;
274 struct net_device *dev = np->dev;
275 struct netpoll_info *npinfo = np->dev->npinfo;
276
277 if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
278 __kfree_skb(skb);
279 return;
280 }
281
282 /* don't get messages out of order, and no recursion */
283 if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
284 struct netdev_queue *txq;
285 unsigned long flags;
286
287 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
288
289 local_irq_save(flags);
290 /* try until next clock tick */
291 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
292 tries > 0; --tries) {
293 if (__netif_tx_trylock(txq)) {
294 if (!netif_tx_queue_stopped(txq))
295 status = dev->hard_start_xmit(skb, dev);
296 __netif_tx_unlock(txq);
297
298 if (status == NETDEV_TX_OK)
299 break;
300
301 }
302
303 /* tickle device maybe there is some cleanup */
304 netpoll_poll(np);
305
306 udelay(USEC_PER_POLL);
307 }
308 local_irq_restore(flags);
309 }
310
311 if (status != NETDEV_TX_OK) {
312 skb_queue_tail(&npinfo->txq, skb);
313 schedule_delayed_work(&npinfo->tx_work,0);
314 }
315 }
316
317 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
318 {
319 int total_len, eth_len, ip_len, udp_len;
320 struct sk_buff *skb;
321 struct udphdr *udph;
322 struct iphdr *iph;
323 struct ethhdr *eth;
324
325 udp_len = len + sizeof(*udph);
326 ip_len = eth_len = udp_len + sizeof(*iph);
327 total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
328
329 skb = find_skb(np, total_len, total_len - len);
330 if (!skb)
331 return;
332
333 skb_copy_to_linear_data(skb, msg, len);
334 skb->len += len;
335
336 skb_push(skb, sizeof(*udph));
337 skb_reset_transport_header(skb);
338 udph = udp_hdr(skb);
339 udph->source = htons(np->local_port);
340 udph->dest = htons(np->remote_port);
341 udph->len = htons(udp_len);
342 udph->check = 0;
343 udph->check = csum_tcpudp_magic(htonl(np->local_ip),
344 htonl(np->remote_ip),
345 udp_len, IPPROTO_UDP,
346 csum_partial((unsigned char *)udph, udp_len, 0));
347 if (udph->check == 0)
348 udph->check = CSUM_MANGLED_0;
349
350 skb_push(skb, sizeof(*iph));
351 skb_reset_network_header(skb);
352 iph = ip_hdr(skb);
353
354 /* iph->version = 4; iph->ihl = 5; */
355 put_unaligned(0x45, (unsigned char *)iph);
356 iph->tos = 0;
357 put_unaligned(htons(ip_len), &(iph->tot_len));
358 iph->id = 0;
359 iph->frag_off = 0;
360 iph->ttl = 64;
361 iph->protocol = IPPROTO_UDP;
362 iph->check = 0;
363 put_unaligned(htonl(np->local_ip), &(iph->saddr));
364 put_unaligned(htonl(np->remote_ip), &(iph->daddr));
365 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
366
367 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
368 skb_reset_mac_header(skb);
369 skb->protocol = eth->h_proto = htons(ETH_P_IP);
370 memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
371 memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
372
373 skb->dev = np->dev;
374
375 netpoll_send_skb(np, skb);
376 }
377
378 static void arp_reply(struct sk_buff *skb)
379 {
380 struct netpoll_info *npinfo = skb->dev->npinfo;
381 struct arphdr *arp;
382 unsigned char *arp_ptr;
383 int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
384 __be32 sip, tip;
385 unsigned char *sha;
386 struct sk_buff *send_skb;
387 struct netpoll *np = NULL;
388
389 if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
390 np = npinfo->rx_np;
391 if (!np)
392 return;
393
394 /* No arp on this interface */
395 if (skb->dev->flags & IFF_NOARP)
396 return;
397
398 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
399 return;
400
401 skb_reset_network_header(skb);
402 skb_reset_transport_header(skb);
403 arp = arp_hdr(skb);
404
405 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
406 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
407 arp->ar_pro != htons(ETH_P_IP) ||
408 arp->ar_op != htons(ARPOP_REQUEST))
409 return;
410
411 arp_ptr = (unsigned char *)(arp+1);
412 /* save the location of the src hw addr */
413 sha = arp_ptr;
414 arp_ptr += skb->dev->addr_len;
415 memcpy(&sip, arp_ptr, 4);
416 arp_ptr += 4;
417 /* if we actually cared about dst hw addr, it would get copied here */
418 arp_ptr += skb->dev->addr_len;
419 memcpy(&tip, arp_ptr, 4);
420
421 /* Should we ignore arp? */
422 if (tip != htonl(np->local_ip) ||
423 ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
424 return;
425
426 size = arp_hdr_len(skb->dev);
427 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
428 LL_RESERVED_SPACE(np->dev));
429
430 if (!send_skb)
431 return;
432
433 skb_reset_network_header(send_skb);
434 arp = (struct arphdr *) skb_put(send_skb, size);
435 send_skb->dev = skb->dev;
436 send_skb->protocol = htons(ETH_P_ARP);
437
438 /* Fill the device header for the ARP frame */
439 if (dev_hard_header(send_skb, skb->dev, ptype,
440 sha, np->dev->dev_addr,
441 send_skb->len) < 0) {
442 kfree_skb(send_skb);
443 return;
444 }
445
446 /*
447 * Fill out the arp protocol part.
448 *
449 * we only support ethernet device type,
450 * which (according to RFC 1390) should always equal 1 (Ethernet).
451 */
452
453 arp->ar_hrd = htons(np->dev->type);
454 arp->ar_pro = htons(ETH_P_IP);
455 arp->ar_hln = np->dev->addr_len;
456 arp->ar_pln = 4;
457 arp->ar_op = htons(type);
458
459 arp_ptr=(unsigned char *)(arp + 1);
460 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
461 arp_ptr += np->dev->addr_len;
462 memcpy(arp_ptr, &tip, 4);
463 arp_ptr += 4;
464 memcpy(arp_ptr, sha, np->dev->addr_len);
465 arp_ptr += np->dev->addr_len;
466 memcpy(arp_ptr, &sip, 4);
467
468 netpoll_send_skb(np, send_skb);
469 }
470
471 int __netpoll_rx(struct sk_buff *skb)
472 {
473 int proto, len, ulen;
474 struct iphdr *iph;
475 struct udphdr *uh;
476 struct netpoll_info *npi = skb->dev->npinfo;
477 struct netpoll *np = npi->rx_np;
478
479 if (!np)
480 goto out;
481 if (skb->dev->type != ARPHRD_ETHER)
482 goto out;
483
484 /* check if netpoll clients need ARP */
485 if (skb->protocol == htons(ETH_P_ARP) &&
486 atomic_read(&trapped)) {
487 skb_queue_tail(&npi->arp_tx, skb);
488 return 1;
489 }
490
491 proto = ntohs(eth_hdr(skb)->h_proto);
492 if (proto != ETH_P_IP)
493 goto out;
494 if (skb->pkt_type == PACKET_OTHERHOST)
495 goto out;
496 if (skb_shared(skb))
497 goto out;
498
499 iph = (struct iphdr *)skb->data;
500 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
501 goto out;
502 if (iph->ihl < 5 || iph->version != 4)
503 goto out;
504 if (!pskb_may_pull(skb, iph->ihl*4))
505 goto out;
506 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
507 goto out;
508
509 len = ntohs(iph->tot_len);
510 if (skb->len < len || len < iph->ihl*4)
511 goto out;
512
513 /*
514 * Our transport medium may have padded the buffer out.
515 * Now We trim to the true length of the frame.
516 */
517 if (pskb_trim_rcsum(skb, len))
518 goto out;
519
520 if (iph->protocol != IPPROTO_UDP)
521 goto out;
522
523 len -= iph->ihl*4;
524 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
525 ulen = ntohs(uh->len);
526
527 if (ulen != len)
528 goto out;
529 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
530 goto out;
531 if (np->local_ip && np->local_ip != ntohl(iph->daddr))
532 goto out;
533 if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
534 goto out;
535 if (np->local_port && np->local_port != ntohs(uh->dest))
536 goto out;
537
538 np->rx_hook(np, ntohs(uh->source),
539 (char *)(uh+1),
540 ulen - sizeof(struct udphdr));
541
542 kfree_skb(skb);
543 return 1;
544
545 out:
546 if (atomic_read(&trapped)) {
547 kfree_skb(skb);
548 return 1;
549 }
550
551 return 0;
552 }
553
554 void netpoll_print_options(struct netpoll *np)
555 {
556 DECLARE_MAC_BUF(mac);
557 printk(KERN_INFO "%s: local port %d\n",
558 np->name, np->local_port);
559 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
560 np->name, HIPQUAD(np->local_ip));
561 printk(KERN_INFO "%s: interface %s\n",
562 np->name, np->dev_name);
563 printk(KERN_INFO "%s: remote port %d\n",
564 np->name, np->remote_port);
565 printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
566 np->name, HIPQUAD(np->remote_ip));
567 printk(KERN_INFO "%s: remote ethernet address %s\n",
568 np->name, print_mac(mac, np->remote_mac));
569 }
570
571 int netpoll_parse_options(struct netpoll *np, char *opt)
572 {
573 char *cur=opt, *delim;
574
575 if (*cur != '@') {
576 if ((delim = strchr(cur, '@')) == NULL)
577 goto parse_failed;
578 *delim = 0;
579 np->local_port = simple_strtol(cur, NULL, 10);
580 cur = delim;
581 }
582 cur++;
583
584 if (*cur != '/') {
585 if ((delim = strchr(cur, '/')) == NULL)
586 goto parse_failed;
587 *delim = 0;
588 np->local_ip = ntohl(in_aton(cur));
589 cur = delim;
590 }
591 cur++;
592
593 if (*cur != ',') {
594 /* parse out dev name */
595 if ((delim = strchr(cur, ',')) == NULL)
596 goto parse_failed;
597 *delim = 0;
598 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
599 cur = delim;
600 }
601 cur++;
602
603 if (*cur != '@') {
604 /* dst port */
605 if ((delim = strchr(cur, '@')) == NULL)
606 goto parse_failed;
607 *delim = 0;
608 np->remote_port = simple_strtol(cur, NULL, 10);
609 cur = delim;
610 }
611 cur++;
612
613 /* dst ip */
614 if ((delim = strchr(cur, '/')) == NULL)
615 goto parse_failed;
616 *delim = 0;
617 np->remote_ip = ntohl(in_aton(cur));
618 cur = delim + 1;
619
620 if (*cur != 0) {
621 /* MAC address */
622 if ((delim = strchr(cur, ':')) == NULL)
623 goto parse_failed;
624 *delim = 0;
625 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
626 cur = delim + 1;
627 if ((delim = strchr(cur, ':')) == NULL)
628 goto parse_failed;
629 *delim = 0;
630 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
631 cur = delim + 1;
632 if ((delim = strchr(cur, ':')) == NULL)
633 goto parse_failed;
634 *delim = 0;
635 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
636 cur = delim + 1;
637 if ((delim = strchr(cur, ':')) == NULL)
638 goto parse_failed;
639 *delim = 0;
640 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
641 cur = delim + 1;
642 if ((delim = strchr(cur, ':')) == NULL)
643 goto parse_failed;
644 *delim = 0;
645 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
646 cur = delim + 1;
647 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
648 }
649
650 netpoll_print_options(np);
651
652 return 0;
653
654 parse_failed:
655 printk(KERN_INFO "%s: couldn't parse config at %s!\n",
656 np->name, cur);
657 return -1;
658 }
659
660 int netpoll_setup(struct netpoll *np)
661 {
662 struct net_device *ndev = NULL;
663 struct in_device *in_dev;
664 struct netpoll_info *npinfo;
665 unsigned long flags;
666 int err;
667
668 if (np->dev_name)
669 ndev = dev_get_by_name(&init_net, np->dev_name);
670 if (!ndev) {
671 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
672 np->name, np->dev_name);
673 return -ENODEV;
674 }
675
676 np->dev = ndev;
677 if (!ndev->npinfo) {
678 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
679 if (!npinfo) {
680 err = -ENOMEM;
681 goto release;
682 }
683
684 npinfo->rx_flags = 0;
685 npinfo->rx_np = NULL;
686
687 spin_lock_init(&npinfo->rx_lock);
688 skb_queue_head_init(&npinfo->arp_tx);
689 skb_queue_head_init(&npinfo->txq);
690 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
691
692 atomic_set(&npinfo->refcnt, 1);
693 } else {
694 npinfo = ndev->npinfo;
695 atomic_inc(&npinfo->refcnt);
696 }
697
698 if (!ndev->poll_controller) {
699 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
700 np->name, np->dev_name);
701 err = -ENOTSUPP;
702 goto release;
703 }
704
705 if (!netif_running(ndev)) {
706 unsigned long atmost, atleast;
707
708 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
709 np->name, np->dev_name);
710
711 rtnl_lock();
712 err = dev_open(ndev);
713 rtnl_unlock();
714
715 if (err) {
716 printk(KERN_ERR "%s: failed to open %s\n",
717 np->name, ndev->name);
718 goto release;
719 }
720
721 atleast = jiffies + HZ/10;
722 atmost = jiffies + 4*HZ;
723 while (!netif_carrier_ok(ndev)) {
724 if (time_after(jiffies, atmost)) {
725 printk(KERN_NOTICE
726 "%s: timeout waiting for carrier\n",
727 np->name);
728 break;
729 }
730 cond_resched();
731 }
732
733 /* If carrier appears to come up instantly, we don't
734 * trust it and pause so that we don't pump all our
735 * queued console messages into the bitbucket.
736 */
737
738 if (time_before(jiffies, atleast)) {
739 printk(KERN_NOTICE "%s: carrier detect appears"
740 " untrustworthy, waiting 4 seconds\n",
741 np->name);
742 msleep(4000);
743 }
744 }
745
746 if (!np->local_ip) {
747 rcu_read_lock();
748 in_dev = __in_dev_get_rcu(ndev);
749
750 if (!in_dev || !in_dev->ifa_list) {
751 rcu_read_unlock();
752 printk(KERN_ERR "%s: no IP address for %s, aborting\n",
753 np->name, np->dev_name);
754 err = -EDESTADDRREQ;
755 goto release;
756 }
757
758 np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
759 rcu_read_unlock();
760 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
761 np->name, HIPQUAD(np->local_ip));
762 }
763
764 if (np->rx_hook) {
765 spin_lock_irqsave(&npinfo->rx_lock, flags);
766 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
767 npinfo->rx_np = np;
768 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
769 }
770
771 /* fill up the skb queue */
772 refill_skbs();
773
774 /* last thing to do is link it to the net device structure */
775 ndev->npinfo = npinfo;
776
777 /* avoid racing with NAPI reading npinfo */
778 synchronize_rcu();
779
780 return 0;
781
782 release:
783 if (!ndev->npinfo)
784 kfree(npinfo);
785 np->dev = NULL;
786 dev_put(ndev);
787 return err;
788 }
789
790 static int __init netpoll_init(void)
791 {
792 skb_queue_head_init(&skb_pool);
793 return 0;
794 }
795 core_initcall(netpoll_init);
796
797 void netpoll_cleanup(struct netpoll *np)
798 {
799 struct netpoll_info *npinfo;
800 unsigned long flags;
801
802 if (np->dev) {
803 npinfo = np->dev->npinfo;
804 if (npinfo) {
805 if (npinfo->rx_np == np) {
806 spin_lock_irqsave(&npinfo->rx_lock, flags);
807 npinfo->rx_np = NULL;
808 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
809 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
810 }
811
812 if (atomic_dec_and_test(&npinfo->refcnt)) {
813 skb_queue_purge(&npinfo->arp_tx);
814 skb_queue_purge(&npinfo->txq);
815 cancel_rearming_delayed_work(&npinfo->tx_work);
816
817 /* clean after last, unfinished work */
818 __skb_queue_purge(&npinfo->txq);
819 kfree(npinfo);
820 np->dev->npinfo = NULL;
821 }
822 }
823
824 dev_put(np->dev);
825 }
826
827 np->dev = NULL;
828 }
829
830 int netpoll_trap(void)
831 {
832 return atomic_read(&trapped);
833 }
834
835 void netpoll_set_trap(int trap)
836 {
837 if (trap)
838 atomic_inc(&trapped);
839 else
840 atomic_dec(&trapped);
841 }
842
843 EXPORT_SYMBOL(netpoll_set_trap);
844 EXPORT_SYMBOL(netpoll_trap);
845 EXPORT_SYMBOL(netpoll_print_options);
846 EXPORT_SYMBOL(netpoll_parse_options);
847 EXPORT_SYMBOL(netpoll_setup);
848 EXPORT_SYMBOL(netpoll_cleanup);
849 EXPORT_SYMBOL(netpoll_send_udp);
850 EXPORT_SYMBOL(netpoll_poll);
linux-next