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writeback: split writeback_inodes_wb
[linux-2.6/next.git] / net / core / netpoll.c
blob94825b109551e81b1c22a09459b5e0262a97d5e4
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/moduleparam.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 <linux/slab.h>
26 #include <net/tcp.h>
27 #include <net/udp.h>
28 #include <asm/unaligned.h>
29 #include <trace/events/napi.h>
30
31 /*
32 * We maintain a small pool of fully-sized skbs, to make sure the
33 * message gets out even in extreme OOM situations.
34 */
35
36 #define MAX_UDP_CHUNK 1460
37 #define MAX_SKBS 32
38 #define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
39
40 static struct sk_buff_head skb_pool;
41
42 static atomic_t trapped;
43
44 #define USEC_PER_POLL 50
45 #define NETPOLL_RX_ENABLED 1
46 #define NETPOLL_RX_DROP 2
47
48 #define MAX_SKB_SIZE \
49 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \
50 sizeof(struct iphdr) + sizeof(struct ethhdr))
51
52 static void zap_completion_queue(void);
53 static void arp_reply(struct sk_buff *skb);
54
55 static unsigned int carrier_timeout = 4;
56 module_param(carrier_timeout, uint, 0644);
57
58 static void queue_process(struct work_struct *work)
59 {
60 struct netpoll_info *npinfo =
61 container_of(work, struct netpoll_info, tx_work.work);
62 struct sk_buff *skb;
63 unsigned long flags;
64
65 while ((skb = skb_dequeue(&npinfo->txq))) {
66 struct net_device *dev = skb->dev;
67 const struct net_device_ops *ops = dev->netdev_ops;
68 struct netdev_queue *txq;
69
70 if (!netif_device_present(dev) || !netif_running(dev)) {
71 __kfree_skb(skb);
72 continue;
73 }
74
75 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
76
77 local_irq_save(flags);
78 __netif_tx_lock(txq, smp_processor_id());
79 if (netif_tx_queue_stopped(txq) ||
80 netif_tx_queue_frozen(txq) ||
81 ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
82 skb_queue_head(&npinfo->txq, skb);
83 __netif_tx_unlock(txq);
84 local_irq_restore(flags);
85
86 schedule_delayed_work(&npinfo->tx_work, HZ/10);
87 return;
88 }
89 __netif_tx_unlock(txq);
90 local_irq_restore(flags);
91 }
92 }
93
94 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
95 unsigned short ulen, __be32 saddr, __be32 daddr)
96 {
97 __wsum psum;
98
99 if (uh->check == 0 || skb_csum_unnecessary(skb))
100 return 0;
101
102 psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
103
104 if (skb->ip_summed == CHECKSUM_COMPLETE &&
105 !csum_fold(csum_add(psum, skb->csum)))
106 return 0;
107
108 skb->csum = psum;
109
110 return __skb_checksum_complete(skb);
111 }
112
113 /*
114 * Check whether delayed processing was scheduled for our NIC. If so,
115 * we attempt to grab the poll lock and use ->poll() to pump the card.
116 * If this fails, either we've recursed in ->poll() or it's already
117 * running on another CPU.
118 *
119 * Note: we don't mask interrupts with this lock because we're using
120 * trylock here and interrupts are already disabled in the softirq
121 * case. Further, we test the poll_owner to avoid recursion on UP
122 * systems where the lock doesn't exist.
123 *
124 * In cases where there is bi-directional communications, reading only
125 * one message at a time can lead to packets being dropped by the
126 * network adapter, forcing superfluous retries and possibly timeouts.
127 * Thus, we set our budget to greater than 1.
128 */
129 static int poll_one_napi(struct netpoll_info *npinfo,
130 struct napi_struct *napi, int budget)
131 {
132 int work;
133
134 /* net_rx_action's ->poll() invocations and our's are
135 * synchronized by this test which is only made while
136 * holding the napi->poll_lock.
137 */
138 if (!test_bit(NAPI_STATE_SCHED, &napi->state))
139 return budget;
140
141 npinfo->rx_flags |= NETPOLL_RX_DROP;
142 atomic_inc(&trapped);
143 set_bit(NAPI_STATE_NPSVC, &napi->state);
144
145 work = napi->poll(napi, budget);
146 trace_napi_poll(napi);
147
148 clear_bit(NAPI_STATE_NPSVC, &napi->state);
149 atomic_dec(&trapped);
150 npinfo->rx_flags &= ~NETPOLL_RX_DROP;
151
152 return budget - work;
153 }
154
155 static void poll_napi(struct net_device *dev)
156 {
157 struct napi_struct *napi;
158 int budget = 16;
159
160 list_for_each_entry(napi, &dev->napi_list, dev_list) {
161 if (napi->poll_owner != smp_processor_id() &&
162 spin_trylock(&napi->poll_lock)) {
163 budget = poll_one_napi(dev->npinfo, napi, budget);
164 spin_unlock(&napi->poll_lock);
165
166 if (!budget)
167 break;
168 }
169 }
170 }
171
172 static void service_arp_queue(struct netpoll_info *npi)
173 {
174 if (npi) {
175 struct sk_buff *skb;
176
177 while ((skb = skb_dequeue(&npi->arp_tx)))
178 arp_reply(skb);
179 }
180 }
181
182 void netpoll_poll_dev(struct net_device *dev)
183 {
184 const struct net_device_ops *ops;
185
186 if (!dev || !netif_running(dev))
187 return;
188
189 ops = dev->netdev_ops;
190 if (!ops->ndo_poll_controller)
191 return;
192
193 /* Process pending work on NIC */
194 ops->ndo_poll_controller(dev);
195
196 poll_napi(dev);
197
198 service_arp_queue(dev->npinfo);
199
200 zap_completion_queue();
201 }
202
203 void netpoll_poll(struct netpoll *np)
204 {
205 netpoll_poll_dev(np->dev);
206 }
207
208 static void refill_skbs(void)
209 {
210 struct sk_buff *skb;
211 unsigned long flags;
212
213 spin_lock_irqsave(&skb_pool.lock, flags);
214 while (skb_pool.qlen < MAX_SKBS) {
215 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
216 if (!skb)
217 break;
218
219 __skb_queue_tail(&skb_pool, skb);
220 }
221 spin_unlock_irqrestore(&skb_pool.lock, flags);
222 }
223
224 static void zap_completion_queue(void)
225 {
226 unsigned long flags;
227 struct softnet_data *sd = &get_cpu_var(softnet_data);
228
229 if (sd->completion_queue) {
230 struct sk_buff *clist;
231
232 local_irq_save(flags);
233 clist = sd->completion_queue;
234 sd->completion_queue = NULL;
235 local_irq_restore(flags);
236
237 while (clist != NULL) {
238 struct sk_buff *skb = clist;
239 clist = clist->next;
240 if (skb->destructor) {
241 atomic_inc(&skb->users);
242 dev_kfree_skb_any(skb); /* put this one back */
243 } else {
244 __kfree_skb(skb);
245 }
246 }
247 }
248
249 put_cpu_var(softnet_data);
250 }
251
252 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
253 {
254 int count = 0;
255 struct sk_buff *skb;
256
257 zap_completion_queue();
258 refill_skbs();
259 repeat:
260
261 skb = alloc_skb(len, GFP_ATOMIC);
262 if (!skb)
263 skb = skb_dequeue(&skb_pool);
264
265 if (!skb) {
266 if (++count < 10) {
267 netpoll_poll(np);
268 goto repeat;
269 }
270 return NULL;
271 }
272
273 atomic_set(&skb->users, 1);
274 skb_reserve(skb, reserve);
275 return skb;
276 }
277
278 static int netpoll_owner_active(struct net_device *dev)
279 {
280 struct napi_struct *napi;
281
282 list_for_each_entry(napi, &dev->napi_list, dev_list) {
283 if (napi->poll_owner == smp_processor_id())
284 return 1;
285 }
286 return 0;
287 }
288
289 void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
290 {
291 int status = NETDEV_TX_BUSY;
292 unsigned long tries;
293 struct net_device *dev = np->dev;
294 const struct net_device_ops *ops = dev->netdev_ops;
295 struct netpoll_info *npinfo = np->dev->npinfo;
296
297 if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
298 __kfree_skb(skb);
299 return;
300 }
301
302 /* don't get messages out of order, and no recursion */
303 if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
304 struct netdev_queue *txq;
305 unsigned long flags;
306
307 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
308
309 local_irq_save(flags);
310 /* try until next clock tick */
311 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
312 tries > 0; --tries) {
313 if (__netif_tx_trylock(txq)) {
314 if (!netif_tx_queue_stopped(txq)) {
315 dev->priv_flags |= IFF_IN_NETPOLL;
316 status = ops->ndo_start_xmit(skb, dev);
317 dev->priv_flags &= ~IFF_IN_NETPOLL;
318 if (status == NETDEV_TX_OK)
319 txq_trans_update(txq);
320 }
321 __netif_tx_unlock(txq);
322
323 if (status == NETDEV_TX_OK)
324 break;
325
326 }
327
328 /* tickle device maybe there is some cleanup */
329 netpoll_poll(np);
330
331 udelay(USEC_PER_POLL);
332 }
333
334 WARN_ONCE(!irqs_disabled(),
335 "netpoll_send_skb(): %s enabled interrupts in poll (%pF)\n",
336 dev->name, ops->ndo_start_xmit);
337
338 local_irq_restore(flags);
339 }
340
341 if (status != NETDEV_TX_OK) {
342 skb_queue_tail(&npinfo->txq, skb);
343 schedule_delayed_work(&npinfo->tx_work,0);
344 }
345 }
346
347 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
348 {
349 int total_len, eth_len, ip_len, udp_len;
350 struct sk_buff *skb;
351 struct udphdr *udph;
352 struct iphdr *iph;
353 struct ethhdr *eth;
354
355 udp_len = len + sizeof(*udph);
356 ip_len = eth_len = udp_len + sizeof(*iph);
357 total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
358
359 skb = find_skb(np, total_len, total_len - len);
360 if (!skb)
361 return;
362
363 skb_copy_to_linear_data(skb, msg, len);
364 skb->len += len;
365
366 skb_push(skb, sizeof(*udph));
367 skb_reset_transport_header(skb);
368 udph = udp_hdr(skb);
369 udph->source = htons(np->local_port);
370 udph->dest = htons(np->remote_port);
371 udph->len = htons(udp_len);
372 udph->check = 0;
373 udph->check = csum_tcpudp_magic(np->local_ip,
374 np->remote_ip,
375 udp_len, IPPROTO_UDP,
376 csum_partial(udph, udp_len, 0));
377 if (udph->check == 0)
378 udph->check = CSUM_MANGLED_0;
379
380 skb_push(skb, sizeof(*iph));
381 skb_reset_network_header(skb);
382 iph = ip_hdr(skb);
383
384 /* iph->version = 4; iph->ihl = 5; */
385 put_unaligned(0x45, (unsigned char *)iph);
386 iph->tos = 0;
387 put_unaligned(htons(ip_len), &(iph->tot_len));
388 iph->id = 0;
389 iph->frag_off = 0;
390 iph->ttl = 64;
391 iph->protocol = IPPROTO_UDP;
392 iph->check = 0;
393 put_unaligned(np->local_ip, &(iph->saddr));
394 put_unaligned(np->remote_ip, &(iph->daddr));
395 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
396
397 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
398 skb_reset_mac_header(skb);
399 skb->protocol = eth->h_proto = htons(ETH_P_IP);
400 memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
401 memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
402
403 skb->dev = np->dev;
404
405 netpoll_send_skb(np, skb);
406 }
407
408 static void arp_reply(struct sk_buff *skb)
409 {
410 struct netpoll_info *npinfo = skb->dev->npinfo;
411 struct arphdr *arp;
412 unsigned char *arp_ptr;
413 int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
414 __be32 sip, tip;
415 unsigned char *sha;
416 struct sk_buff *send_skb;
417 struct netpoll *np, *tmp;
418 unsigned long flags;
419 int hits = 0;
420
421 if (list_empty(&npinfo->rx_np))
422 return;
423
424 /* Before checking the packet, we do some early
425 inspection whether this is interesting at all */
426 spin_lock_irqsave(&npinfo->rx_lock, flags);
427 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
428 if (np->dev == skb->dev)
429 hits++;
430 }
431 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
432
433 /* No netpoll struct is using this dev */
434 if (!hits)
435 return;
436
437 /* No arp on this interface */
438 if (skb->dev->flags & IFF_NOARP)
439 return;
440
441 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
442 return;
443
444 skb_reset_network_header(skb);
445 skb_reset_transport_header(skb);
446 arp = arp_hdr(skb);
447
448 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
449 arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
450 arp->ar_pro != htons(ETH_P_IP) ||
451 arp->ar_op != htons(ARPOP_REQUEST))
452 return;
453
454 arp_ptr = (unsigned char *)(arp+1);
455 /* save the location of the src hw addr */
456 sha = arp_ptr;
457 arp_ptr += skb->dev->addr_len;
458 memcpy(&sip, arp_ptr, 4);
459 arp_ptr += 4;
460 /* If we actually cared about dst hw addr,
461 it would get copied here */
462 arp_ptr += skb->dev->addr_len;
463 memcpy(&tip, arp_ptr, 4);
464
465 /* Should we ignore arp? */
466 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
467 return;
468
469 size = arp_hdr_len(skb->dev);
470
471 spin_lock_irqsave(&npinfo->rx_lock, flags);
472 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
473 if (tip != np->local_ip)
474 continue;
475
476 send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
477 LL_RESERVED_SPACE(np->dev));
478 if (!send_skb)
479 continue;
480
481 skb_reset_network_header(send_skb);
482 arp = (struct arphdr *) skb_put(send_skb, size);
483 send_skb->dev = skb->dev;
484 send_skb->protocol = htons(ETH_P_ARP);
485
486 /* Fill the device header for the ARP frame */
487 if (dev_hard_header(send_skb, skb->dev, ptype,
488 sha, np->dev->dev_addr,
489 send_skb->len) < 0) {
490 kfree_skb(send_skb);
491 continue;
492 }
493
494 /*
495 * Fill out the arp protocol part.
496 *
497 * we only support ethernet device type,
498 * which (according to RFC 1390) should
499 * always equal 1 (Ethernet).
500 */
501
502 arp->ar_hrd = htons(np->dev->type);
503 arp->ar_pro = htons(ETH_P_IP);
504 arp->ar_hln = np->dev->addr_len;
505 arp->ar_pln = 4;
506 arp->ar_op = htons(type);
507
508 arp_ptr = (unsigned char *)(arp + 1);
509 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
510 arp_ptr += np->dev->addr_len;
511 memcpy(arp_ptr, &tip, 4);
512 arp_ptr += 4;
513 memcpy(arp_ptr, sha, np->dev->addr_len);
514 arp_ptr += np->dev->addr_len;
515 memcpy(arp_ptr, &sip, 4);
516
517 netpoll_send_skb(np, send_skb);
518
519 /* If there are several rx_hooks for the same address,
520 we're fine by sending a single reply */
521 break;
522 }
523 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
524 }
525
526 int __netpoll_rx(struct sk_buff *skb)
527 {
528 int proto, len, ulen;
529 int hits = 0;
530 struct iphdr *iph;
531 struct udphdr *uh;
532 struct netpoll_info *npinfo = skb->dev->npinfo;
533 struct netpoll *np, *tmp;
534
535 if (list_empty(&npinfo->rx_np))
536 goto out;
537
538 if (skb->dev->type != ARPHRD_ETHER)
539 goto out;
540
541 /* check if netpoll clients need ARP */
542 if (skb->protocol == htons(ETH_P_ARP) &&
543 atomic_read(&trapped)) {
544 skb_queue_tail(&npinfo->arp_tx, skb);
545 return 1;
546 }
547
548 proto = ntohs(eth_hdr(skb)->h_proto);
549 if (proto != ETH_P_IP)
550 goto out;
551 if (skb->pkt_type == PACKET_OTHERHOST)
552 goto out;
553 if (skb_shared(skb))
554 goto out;
555
556 iph = (struct iphdr *)skb->data;
557 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
558 goto out;
559 if (iph->ihl < 5 || iph->version != 4)
560 goto out;
561 if (!pskb_may_pull(skb, iph->ihl*4))
562 goto out;
563 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
564 goto out;
565
566 len = ntohs(iph->tot_len);
567 if (skb->len < len || len < iph->ihl*4)
568 goto out;
569
570 /*
571 * Our transport medium may have padded the buffer out.
572 * Now We trim to the true length of the frame.
573 */
574 if (pskb_trim_rcsum(skb, len))
575 goto out;
576
577 if (iph->protocol != IPPROTO_UDP)
578 goto out;
579
580 len -= iph->ihl*4;
581 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
582 ulen = ntohs(uh->len);
583
584 if (ulen != len)
585 goto out;
586 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
587 goto out;
588
589 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
590 if (np->local_ip && np->local_ip != iph->daddr)
591 continue;
592 if (np->remote_ip && np->remote_ip != iph->saddr)
593 continue;
594 if (np->local_port && np->local_port != ntohs(uh->dest))
595 continue;
596
597 np->rx_hook(np, ntohs(uh->source),
598 (char *)(uh+1),
599 ulen - sizeof(struct udphdr));
600 hits++;
601 }
602
603 if (!hits)
604 goto out;
605
606 kfree_skb(skb);
607 return 1;
608
609 out:
610 if (atomic_read(&trapped)) {
611 kfree_skb(skb);
612 return 1;
613 }
614
615 return 0;
616 }
617
618 void netpoll_print_options(struct netpoll *np)
619 {
620 printk(KERN_INFO "%s: local port %d\n",
621 np->name, np->local_port);
622 printk(KERN_INFO "%s: local IP %pI4\n",
623 np->name, &np->local_ip);
624 printk(KERN_INFO "%s: interface '%s'\n",
625 np->name, np->dev_name);
626 printk(KERN_INFO "%s: remote port %d\n",
627 np->name, np->remote_port);
628 printk(KERN_INFO "%s: remote IP %pI4\n",
629 np->name, &np->remote_ip);
630 printk(KERN_INFO "%s: remote ethernet address %pM\n",
631 np->name, np->remote_mac);
632 }
633
634 int netpoll_parse_options(struct netpoll *np, char *opt)
635 {
636 char *cur=opt, *delim;
637
638 if (*cur != '@') {
639 if ((delim = strchr(cur, '@')) == NULL)
640 goto parse_failed;
641 *delim = 0;
642 np->local_port = simple_strtol(cur, NULL, 10);
643 cur = delim;
644 }
645 cur++;
646
647 if (*cur != '/') {
648 if ((delim = strchr(cur, '/')) == NULL)
649 goto parse_failed;
650 *delim = 0;
651 np->local_ip = in_aton(cur);
652 cur = delim;
653 }
654 cur++;
655
656 if (*cur != ',') {
657 /* parse out dev name */
658 if ((delim = strchr(cur, ',')) == NULL)
659 goto parse_failed;
660 *delim = 0;
661 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
662 cur = delim;
663 }
664 cur++;
665
666 if (*cur != '@') {
667 /* dst port */
668 if ((delim = strchr(cur, '@')) == NULL)
669 goto parse_failed;
670 *delim = 0;
671 if (*cur == ' ' || *cur == '\t')
672 printk(KERN_INFO "%s: warning: whitespace"
673 "is not allowed\n", np->name);
674 np->remote_port = simple_strtol(cur, NULL, 10);
675 cur = delim;
676 }
677 cur++;
678
679 /* dst ip */
680 if ((delim = strchr(cur, '/')) == NULL)
681 goto parse_failed;
682 *delim = 0;
683 np->remote_ip = in_aton(cur);
684 cur = delim + 1;
685
686 if (*cur != 0) {
687 /* MAC address */
688 if ((delim = strchr(cur, ':')) == NULL)
689 goto parse_failed;
690 *delim = 0;
691 np->remote_mac[0] = simple_strtol(cur, NULL, 16);
692 cur = delim + 1;
693 if ((delim = strchr(cur, ':')) == NULL)
694 goto parse_failed;
695 *delim = 0;
696 np->remote_mac[1] = simple_strtol(cur, NULL, 16);
697 cur = delim + 1;
698 if ((delim = strchr(cur, ':')) == NULL)
699 goto parse_failed;
700 *delim = 0;
701 np->remote_mac[2] = simple_strtol(cur, NULL, 16);
702 cur = delim + 1;
703 if ((delim = strchr(cur, ':')) == NULL)
704 goto parse_failed;
705 *delim = 0;
706 np->remote_mac[3] = simple_strtol(cur, NULL, 16);
707 cur = delim + 1;
708 if ((delim = strchr(cur, ':')) == NULL)
709 goto parse_failed;
710 *delim = 0;
711 np->remote_mac[4] = simple_strtol(cur, NULL, 16);
712 cur = delim + 1;
713 np->remote_mac[5] = simple_strtol(cur, NULL, 16);
714 }
715
716 netpoll_print_options(np);
717
718 return 0;
719
720 parse_failed:
721 printk(KERN_INFO "%s: couldn't parse config at '%s'!\n",
722 np->name, cur);
723 return -1;
724 }
725
726 int netpoll_setup(struct netpoll *np)
727 {
728 struct net_device *ndev = NULL;
729 struct in_device *in_dev;
730 struct netpoll_info *npinfo;
731 struct netpoll *npe, *tmp;
732 unsigned long flags;
733 int err;
734
735 if (np->dev_name)
736 ndev = dev_get_by_name(&init_net, np->dev_name);
737 if (!ndev) {
738 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
739 np->name, np->dev_name);
740 return -ENODEV;
741 }
742
743 np->dev = ndev;
744 if (!ndev->npinfo) {
745 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
746 if (!npinfo) {
747 err = -ENOMEM;
748 goto put;
749 }
750
751 npinfo->rx_flags = 0;
752 INIT_LIST_HEAD(&npinfo->rx_np);
753
754 spin_lock_init(&npinfo->rx_lock);
755 skb_queue_head_init(&npinfo->arp_tx);
756 skb_queue_head_init(&npinfo->txq);
757 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
758
759 atomic_set(&npinfo->refcnt, 1);
760 } else {
761 npinfo = ndev->npinfo;
762 atomic_inc(&npinfo->refcnt);
763 }
764
765 npinfo->netpoll = np;
766
767 if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
768 !ndev->netdev_ops->ndo_poll_controller) {
769 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
770 np->name, np->dev_name);
771 err = -ENOTSUPP;
772 goto release;
773 }
774
775 if (!netif_running(ndev)) {
776 unsigned long atmost, atleast;
777
778 printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
779 np->name, np->dev_name);
780
781 rtnl_lock();
782 err = dev_open(ndev);
783 rtnl_unlock();
784
785 if (err) {
786 printk(KERN_ERR "%s: failed to open %s\n",
787 np->name, ndev->name);
788 goto release;
789 }
790
791 atleast = jiffies + HZ/10;
792 atmost = jiffies + carrier_timeout * HZ;
793 while (!netif_carrier_ok(ndev)) {
794 if (time_after(jiffies, atmost)) {
795 printk(KERN_NOTICE
796 "%s: timeout waiting for carrier\n",
797 np->name);
798 break;
799 }
800 msleep(1);
801 }
802
803 /* If carrier appears to come up instantly, we don't
804 * trust it and pause so that we don't pump all our
805 * queued console messages into the bitbucket.
806 */
807
808 if (time_before(jiffies, atleast)) {
809 printk(KERN_NOTICE "%s: carrier detect appears"
810 " untrustworthy, waiting 4 seconds\n",
811 np->name);
812 msleep(4000);
813 }
814 }
815
816 if (!np->local_ip) {
817 rcu_read_lock();
818 in_dev = __in_dev_get_rcu(ndev);
819
820 if (!in_dev || !in_dev->ifa_list) {
821 rcu_read_unlock();
822 printk(KERN_ERR "%s: no IP address for %s, aborting\n",
823 np->name, np->dev_name);
824 err = -EDESTADDRREQ;
825 goto release;
826 }
827
828 np->local_ip = in_dev->ifa_list->ifa_local;
829 rcu_read_unlock();
830 printk(KERN_INFO "%s: local IP %pI4\n", np->name, &np->local_ip);
831 }
832
833 if (np->rx_hook) {
834 spin_lock_irqsave(&npinfo->rx_lock, flags);
835 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
836 list_add_tail(&np->rx, &npinfo->rx_np);
837 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
838 }
839
840 /* fill up the skb queue */
841 refill_skbs();
842
843 /* last thing to do is link it to the net device structure */
844 ndev->npinfo = npinfo;
845
846 /* avoid racing with NAPI reading npinfo */
847 synchronize_rcu();
848
849 return 0;
850
851 release:
852 if (!ndev->npinfo) {
853 spin_lock_irqsave(&npinfo->rx_lock, flags);
854 list_for_each_entry_safe(npe, tmp, &npinfo->rx_np, rx) {
855 npe->dev = NULL;
856 }
857 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
858
859 kfree(npinfo);
860 }
861 put:
862 dev_put(ndev);
863 return err;
864 }
865
866 static int __init netpoll_init(void)
867 {
868 skb_queue_head_init(&skb_pool);
869 return 0;
870 }
871 core_initcall(netpoll_init);
872
873 void netpoll_cleanup(struct netpoll *np)
874 {
875 struct netpoll_info *npinfo;
876 unsigned long flags;
877
878 if (np->dev) {
879 npinfo = np->dev->npinfo;
880 if (npinfo) {
881 if (!list_empty(&npinfo->rx_np)) {
882 spin_lock_irqsave(&npinfo->rx_lock, flags);
883 list_del(&np->rx);
884 if (list_empty(&npinfo->rx_np))
885 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
886 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
887 }
888
889 if (atomic_dec_and_test(&npinfo->refcnt)) {
890 const struct net_device_ops *ops;
891 skb_queue_purge(&npinfo->arp_tx);
892 skb_queue_purge(&npinfo->txq);
893 cancel_rearming_delayed_work(&npinfo->tx_work);
894
895 /* clean after last, unfinished work */
896 __skb_queue_purge(&npinfo->txq);
897 kfree(npinfo);
898 ops = np->dev->netdev_ops;
899 if (ops->ndo_netpoll_cleanup)
900 ops->ndo_netpoll_cleanup(np->dev);
901 else
902 np->dev->npinfo = NULL;
903 }
904 }
905
906 dev_put(np->dev);
907 }
908
909 np->dev = NULL;
910 }
911
912 int netpoll_trap(void)
913 {
914 return atomic_read(&trapped);
915 }
916
917 void netpoll_set_trap(int trap)
918 {
919 if (trap)
920 atomic_inc(&trapped);
921 else
922 atomic_dec(&trapped);
923 }
924
925 EXPORT_SYMBOL(netpoll_send_skb);
926 EXPORT_SYMBOL(netpoll_set_trap);
927 EXPORT_SYMBOL(netpoll_trap);
928 EXPORT_SYMBOL(netpoll_print_options);
929 EXPORT_SYMBOL(netpoll_parse_options);
930 EXPORT_SYMBOL(netpoll_setup);
931 EXPORT_SYMBOL(netpoll_cleanup);
932 EXPORT_SYMBOL(netpoll_send_udp);
933 EXPORT_SYMBOL(netpoll_poll_dev);
934 EXPORT_SYMBOL(netpoll_poll);
linux-next