Pileus Git - ~andy/linux/blob - 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/moduleparam.h>
  15 #include <linux/kernel.h>
  16 #include <linux/netdevice.h>
  17 #include <linux/etherdevice.h>
  18 #include <linux/string.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/inetdevice.h>
  21 #include <linux/inet.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/netpoll.h>
  24 #include <linux/sched.h>
  25 #include <linux/delay.h>
  26 #include <linux/rcupdate.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/slab.h>
  29 #include <linux/export.h>
  30 #include <linux/if_vlan.h>
  31 #include <net/tcp.h>
  32 #include <net/udp.h>
  33 #include <net/addrconf.h>
  34 #include <net/ndisc.h>
  35 #include <net/ip6_checksum.h>
  36 #include <asm/unaligned.h>
  37 #include <trace/events/napi.h>
  38
  39 /*
  40  * We maintain a small pool of fully-sized skbs, to make sure the
  41  * message gets out even in extreme OOM situations.
  42  */
  43
  44 #define MAX_UDP_CHUNK 1460
  45 #define MAX_SKBS 32
  46
  47 static struct sk_buff_head skb_pool;
  48
  49 static atomic_t trapped;
  50
  51 DEFINE_STATIC_SRCU(netpoll_srcu);
  52
  53 #define USEC_PER_POLL   50
  54 #define NETPOLL_RX_ENABLED  1
  55 #define NETPOLL_RX_DROP     2
  56
  57 #define MAX_SKB_SIZE                                                    \
  58         (sizeof(struct ethhdr) +                                        \
  59          sizeof(struct iphdr) +                                         \
  60          sizeof(struct udphdr) +                                        \
  61          MAX_UDP_CHUNK)
  62
  63 static void zap_completion_queue(void);
  64 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo);
  65 static void netpoll_async_cleanup(struct work_struct *work);
  66
  67 static unsigned int carrier_timeout = 4;
  68 module_param(carrier_timeout, uint, 0644);
  69
  70 #define np_info(np, fmt, ...)                           \
  71         pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
  72 #define np_err(np, fmt, ...)                            \
  73         pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
  74 #define np_notice(np, fmt, ...)                         \
  75         pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
  76
  77 static void queue_process(struct work_struct *work)
  78 {
  79         struct netpoll_info *npinfo =
  80                 container_of(work, struct netpoll_info, tx_work.work);
  81         struct sk_buff *skb;
  82         unsigned long flags;
  83
  84         while ((skb = skb_dequeue(&npinfo->txq))) {
  85                 struct net_device *dev = skb->dev;
  86                 const struct net_device_ops *ops = dev->netdev_ops;
  87                 struct netdev_queue *txq;
  88
  89                 if (!netif_device_present(dev) || !netif_running(dev)) {
  90                         __kfree_skb(skb);
  91                         continue;
  92                 }
  93
  94                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  95
  96                 local_irq_save(flags);
  97                 __netif_tx_lock(txq, smp_processor_id());
  98                 if (netif_xmit_frozen_or_stopped(txq) ||
  99                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
 100                         skb_queue_head(&npinfo->txq, skb);
 101                         __netif_tx_unlock(txq);
 102                         local_irq_restore(flags);
 103
 104                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
 105                         return;
 106                 }
 107                 __netif_tx_unlock(txq);
 108                 local_irq_restore(flags);
 109         }
 110 }
 111
 112 static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
 113                             unsigned short ulen, __be32 saddr, __be32 daddr)
 114 {
 115         __wsum psum;
 116
 117         if (uh->check == 0 || skb_csum_unnecessary(skb))
 118                 return 0;
 119
 120         psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
 121
 122         if (skb->ip_summed == CHECKSUM_COMPLETE &&
 123             !csum_fold(csum_add(psum, skb->csum)))
 124                 return 0;
 125
 126         skb->csum = psum;
 127
 128         return __skb_checksum_complete(skb);
 129 }
 130
 131 /*
 132  * Check whether delayed processing was scheduled for our NIC. If so,
 133  * we attempt to grab the poll lock and use ->poll() to pump the card.
 134  * If this fails, either we've recursed in ->poll() or it's already
 135  * running on another CPU.
 136  *
 137  * Note: we don't mask interrupts with this lock because we're using
 138  * trylock here and interrupts are already disabled in the softirq
 139  * case. Further, we test the poll_owner to avoid recursion on UP
 140  * systems where the lock doesn't exist.
 141  *
 142  * In cases where there is bi-directional communications, reading only
 143  * one message at a time can lead to packets being dropped by the
 144  * network adapter, forcing superfluous retries and possibly timeouts.
 145  * Thus, we set our budget to greater than 1.
 146  */
 147 static int poll_one_napi(struct netpoll_info *npinfo,
 148                          struct napi_struct *napi, int budget)
 149 {
 150         int work;
 151
 152         /* net_rx_action's ->poll() invocations and our's are
 153          * synchronized by this test which is only made while
 154          * holding the napi->poll_lock.
 155          */
 156         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 157                 return budget;
 158
 159         npinfo->rx_flags |= NETPOLL_RX_DROP;
 160         atomic_inc(&trapped);
 161         set_bit(NAPI_STATE_NPSVC, &napi->state);
 162
 163         work = napi->poll(napi, budget);
 164         trace_napi_poll(napi);
 165
 166         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 167         atomic_dec(&trapped);
 168         npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 169
 170         return budget - work;
 171 }
 172
 173 static void poll_napi(struct net_device *dev)
 174 {
 175         struct napi_struct *napi;
 176         int budget = 16;
 177
 178         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 179                 if (napi->poll_owner != smp_processor_id() &&
 180                     spin_trylock(&napi->poll_lock)) {
 181                         budget = poll_one_napi(rcu_dereference_bh(dev->npinfo),
 182                                                napi, budget);
 183                         spin_unlock(&napi->poll_lock);
 184
 185                         if (!budget)
 186                                 break;
 187                 }
 188         }
 189 }
 190
 191 static void service_neigh_queue(struct netpoll_info *npi)
 192 {
 193         if (npi) {
 194                 struct sk_buff *skb;
 195
 196                 while ((skb = skb_dequeue(&npi->neigh_tx)))
 197                         netpoll_neigh_reply(skb, npi);
 198         }
 199 }
 200
 201 static void netpoll_poll_dev(struct net_device *dev)
 202 {
 203         const struct net_device_ops *ops;
 204         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 205
 206         /* Don't do any rx activity if the dev_lock mutex is held
 207          * the dev_open/close paths use this to block netpoll activity
 208          * while changing device state
 209          */
 210         if (down_trylock(&ni->dev_lock))
 211                 return;
 212
 213         if (!netif_running(dev)) {
 214                 up(&ni->dev_lock);
 215                 return;
 216         }
 217
 218         ops = dev->netdev_ops;
 219         if (!ops->ndo_poll_controller) {
 220                 up(&ni->dev_lock);
 221                 return;
 222         }
 223
 224         /* Process pending work on NIC */
 225         ops->ndo_poll_controller(dev);
 226
 227         poll_napi(dev);
 228
 229         up(&ni->dev_lock);
 230
 231         if (dev->flags & IFF_SLAVE) {
 232                 if (ni) {
 233                         struct net_device *bond_dev;
 234                         struct sk_buff *skb;
 235                         struct netpoll_info *bond_ni;
 236
 237                         bond_dev = netdev_master_upper_dev_get_rcu(dev);
 238                         bond_ni = rcu_dereference_bh(bond_dev->npinfo);
 239                         while ((skb = skb_dequeue(&ni->neigh_tx))) {
 240                                 skb->dev = bond_dev;
 241                                 skb_queue_tail(&bond_ni->neigh_tx, skb);
 242                         }
 243                 }
 244         }
 245
 246         service_neigh_queue(ni);
 247
 248         zap_completion_queue();
 249 }
 250
 251 void netpoll_rx_disable(struct net_device *dev)
 252 {
 253         struct netpoll_info *ni;
 254         int idx;
 255         might_sleep();
 256         idx = srcu_read_lock(&netpoll_srcu);
 257         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 258         if (ni)
 259                 down(&ni->dev_lock);
 260         srcu_read_unlock(&netpoll_srcu, idx);
 261 }
 262 EXPORT_SYMBOL(netpoll_rx_disable);
 263
 264 void netpoll_rx_enable(struct net_device *dev)
 265 {
 266         struct netpoll_info *ni;
 267         rcu_read_lock();
 268         ni = rcu_dereference(dev->npinfo);
 269         if (ni)
 270                 up(&ni->dev_lock);
 271         rcu_read_unlock();
 272 }
 273 EXPORT_SYMBOL(netpoll_rx_enable);
 274
 275 static void refill_skbs(void)
 276 {
 277         struct sk_buff *skb;
 278         unsigned long flags;
 279
 280         spin_lock_irqsave(&skb_pool.lock, flags);
 281         while (skb_pool.qlen < MAX_SKBS) {
 282                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 283                 if (!skb)
 284                         break;
 285
 286                 __skb_queue_tail(&skb_pool, skb);
 287         }
 288         spin_unlock_irqrestore(&skb_pool.lock, flags);
 289 }
 290
 291 static void zap_completion_queue(void)
 292 {
 293         unsigned long flags;
 294         struct softnet_data *sd = &get_cpu_var(softnet_data);
 295
 296         if (sd->completion_queue) {
 297                 struct sk_buff *clist;
 298
 299                 local_irq_save(flags);
 300                 clist = sd->completion_queue;
 301                 sd->completion_queue = NULL;
 302                 local_irq_restore(flags);
 303
 304                 while (clist != NULL) {
 305                         struct sk_buff *skb = clist;
 306                         clist = clist->next;
 307                         if (skb->destructor) {
 308                                 atomic_inc(&skb->users);
 309                                 dev_kfree_skb_any(skb); /* put this one back */
 310                         } else {
 311                                 __kfree_skb(skb);
 312                         }
 313                 }
 314         }
 315
 316         put_cpu_var(softnet_data);
 317 }
 318
 319 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 320 {
 321         int count = 0;
 322         struct sk_buff *skb;
 323
 324         zap_completion_queue();
 325         refill_skbs();
 326 repeat:
 327
 328         skb = alloc_skb(len, GFP_ATOMIC);
 329         if (!skb)
 330                 skb = skb_dequeue(&skb_pool);
 331
 332         if (!skb) {
 333                 if (++count < 10) {
 334                         netpoll_poll_dev(np->dev);
 335                         goto repeat;
 336                 }
 337                 return NULL;
 338         }
 339
 340         atomic_set(&skb->users, 1);
 341         skb_reserve(skb, reserve);
 342         return skb;
 343 }
 344
 345 static int netpoll_owner_active(struct net_device *dev)
 346 {
 347         struct napi_struct *napi;
 348
 349         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 350                 if (napi->poll_owner == smp_processor_id())
 351                         return 1;
 352         }
 353         return 0;
 354 }
 355
 356 /* call with IRQ disabled */
 357 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 358                              struct net_device *dev)
 359 {
 360         int status = NETDEV_TX_BUSY;
 361         unsigned long tries;
 362         const struct net_device_ops *ops = dev->netdev_ops;
 363         /* It is up to the caller to keep npinfo alive. */
 364         struct netpoll_info *npinfo;
 365
 366         WARN_ON_ONCE(!irqs_disabled());
 367
 368         npinfo = rcu_dereference_bh(np->dev->npinfo);
 369         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 370                 __kfree_skb(skb);
 371                 return;
 372         }
 373
 374         /* don't get messages out of order, and no recursion */
 375         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 376                 struct netdev_queue *txq;
 377
 378                 txq = netdev_pick_tx(dev, skb, NULL);
 379
 380                 /* try until next clock tick */
 381                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 382                      tries > 0; --tries) {
 383                         if (__netif_tx_trylock(txq)) {
 384                                 if (!netif_xmit_stopped(txq)) {
 385                                         if (vlan_tx_tag_present(skb) &&
 386                                             !vlan_hw_offload_capable(netif_skb_features(skb),
 387                                                                      skb->vlan_proto)) {
 388                                                 skb = __vlan_put_tag(skb, skb->vlan_proto, vlan_tx_tag_get(skb));
 389                                                 if (unlikely(!skb)) {
 390                                                         /* This is actually a packet drop, but we
 391                                                          * don't want the code at the end of this
 392                                                          * function to try and re-queue a NULL skb.
 393                                                          */
 394                                                         status = NETDEV_TX_OK;
 395                                                         goto unlock_txq;
 396                                                 }
 397                                                 skb->vlan_tci = 0;
 398                                         }
 399
 400                                         status = ops->ndo_start_xmit(skb, dev);
 401                                         if (status == NETDEV_TX_OK)
 402                                                 txq_trans_update(txq);
 403                                 }
 404                         unlock_txq:
 405                                 __netif_tx_unlock(txq);
 406
 407                                 if (status == NETDEV_TX_OK)
 408                                         break;
 409
 410                         }
 411
 412                         /* tickle device maybe there is some cleanup */
 413                         netpoll_poll_dev(np->dev);
 414
 415                         udelay(USEC_PER_POLL);
 416                 }
 417
 418                 WARN_ONCE(!irqs_disabled(),
 419                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 420                         dev->name, ops->ndo_start_xmit);
 421
 422         }
 423
 424         if (status != NETDEV_TX_OK) {
 425                 skb_queue_tail(&npinfo->txq, skb);
 426                 schedule_delayed_work(&npinfo->tx_work,0);
 427         }
 428 }
 429 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 430
 431 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 432 {
 433         int total_len, ip_len, udp_len;
 434         struct sk_buff *skb;
 435         struct udphdr *udph;
 436         struct iphdr *iph;
 437         struct ethhdr *eth;
 438         static atomic_t ip_ident;
 439         struct ipv6hdr *ip6h;
 440
 441         udp_len = len + sizeof(*udph);
 442         if (np->ipv6)
 443                 ip_len = udp_len + sizeof(*ip6h);
 444         else
 445                 ip_len = udp_len + sizeof(*iph);
 446
 447         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 448
 449         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 450                        total_len - len);
 451         if (!skb)
 452                 return;
 453
 454         skb_copy_to_linear_data(skb, msg, len);
 455         skb_put(skb, len);
 456
 457         skb_push(skb, sizeof(*udph));
 458         skb_reset_transport_header(skb);
 459         udph = udp_hdr(skb);
 460         udph->source = htons(np->local_port);
 461         udph->dest = htons(np->remote_port);
 462         udph->len = htons(udp_len);
 463
 464         if (np->ipv6) {
 465                 udph->check = 0;
 466                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 467                                               &np->remote_ip.in6,
 468                                               udp_len, IPPROTO_UDP,
 469                                               csum_partial(udph, udp_len, 0));
 470                 if (udph->check == 0)
 471                         udph->check = CSUM_MANGLED_0;
 472
 473                 skb_push(skb, sizeof(*ip6h));
 474                 skb_reset_network_header(skb);
 475                 ip6h = ipv6_hdr(skb);
 476
 477                 /* ip6h->version = 6; ip6h->priority = 0; */
 478                 put_unaligned(0x60, (unsigned char *)ip6h);
 479                 ip6h->flow_lbl[0] = 0;
 480                 ip6h->flow_lbl[1] = 0;
 481                 ip6h->flow_lbl[2] = 0;
 482
 483                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 484                 ip6h->nexthdr = IPPROTO_UDP;
 485                 ip6h->hop_limit = 32;
 486                 ip6h->saddr = np->local_ip.in6;
 487                 ip6h->daddr = np->remote_ip.in6;
 488
 489                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 490                 skb_reset_mac_header(skb);
 491                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 492         } else {
 493                 udph->check = 0;
 494                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 495                                                 np->remote_ip.ip,
 496                                                 udp_len, IPPROTO_UDP,
 497                                                 csum_partial(udph, udp_len, 0));
 498                 if (udph->check == 0)
 499                         udph->check = CSUM_MANGLED_0;
 500
 501                 skb_push(skb, sizeof(*iph));
 502                 skb_reset_network_header(skb);
 503                 iph = ip_hdr(skb);
 504
 505                 /* iph->version = 4; iph->ihl = 5; */
 506                 put_unaligned(0x45, (unsigned char *)iph);
 507                 iph->tos      = 0;
 508                 put_unaligned(htons(ip_len), &(iph->tot_len));
 509                 iph->id       = htons(atomic_inc_return(&ip_ident));
 510                 iph->frag_off = 0;
 511                 iph->ttl      = 64;
 512                 iph->protocol = IPPROTO_UDP;
 513                 iph->check    = 0;
 514                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 515                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 516                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 517
 518                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 519                 skb_reset_mac_header(skb);
 520                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 521         }
 522
 523         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 524         ether_addr_copy(eth->h_dest, np->remote_mac);
 525
 526         skb->dev = np->dev;
 527
 528         netpoll_send_skb(np, skb);
 529 }
 530 EXPORT_SYMBOL(netpoll_send_udp);
 531
 532 static void netpoll_neigh_reply(struct sk_buff *skb, struct netpoll_info *npinfo)
 533 {
 534         int size, type = ARPOP_REPLY;
 535         __be32 sip, tip;
 536         unsigned char *sha;
 537         struct sk_buff *send_skb;
 538         struct netpoll *np, *tmp;
 539         unsigned long flags;
 540         int hlen, tlen;
 541         int hits = 0, proto;
 542
 543         if (list_empty(&npinfo->rx_np))
 544                 return;
 545
 546         /* Before checking the packet, we do some early
 547            inspection whether this is interesting at all */
 548         spin_lock_irqsave(&npinfo->rx_lock, flags);
 549         list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 550                 if (np->dev == skb->dev)
 551                         hits++;
 552         }
 553         spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 554
 555         /* No netpoll struct is using this dev */
 556         if (!hits)
 557                 return;
 558
 559         proto = ntohs(eth_hdr(skb)->h_proto);
 560         if (proto == ETH_P_ARP) {
 561                 struct arphdr *arp;
 562                 unsigned char *arp_ptr;
 563                 /* No arp on this interface */
 564                 if (skb->dev->flags & IFF_NOARP)
 565                         return;
 566
 567                 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 568                         return;
 569
 570                 skb_reset_network_header(skb);
 571                 skb_reset_transport_header(skb);
 572                 arp = arp_hdr(skb);
 573
 574                 if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
 575                      arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
 576                     arp->ar_pro != htons(ETH_P_IP) ||
 577                     arp->ar_op != htons(ARPOP_REQUEST))
 578                         return;
 579
 580                 arp_ptr = (unsigned char *)(arp+1);
 581                 /* save the location of the src hw addr */
 582                 sha = arp_ptr;
 583                 arp_ptr += skb->dev->addr_len;
 584                 memcpy(&sip, arp_ptr, 4);
 585                 arp_ptr += 4;
 586                 /* If we actually cared about dst hw addr,
 587                    it would get copied here */
 588                 arp_ptr += skb->dev->addr_len;
 589                 memcpy(&tip, arp_ptr, 4);
 590
 591                 /* Should we ignore arp? */
 592                 if (ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
 593                         return;
 594
 595                 size = arp_hdr_len(skb->dev);
 596
 597                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 598                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 599                         if (tip != np->local_ip.ip)
 600                                 continue;
 601
 602                         hlen = LL_RESERVED_SPACE(np->dev);
 603                         tlen = np->dev->needed_tailroom;
 604                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 605                         if (!send_skb)
 606                                 continue;
 607
 608                         skb_reset_network_header(send_skb);
 609                         arp = (struct arphdr *) skb_put(send_skb, size);
 610                         send_skb->dev = skb->dev;
 611                         send_skb->protocol = htons(ETH_P_ARP);
 612
 613                         /* Fill the device header for the ARP frame */
 614                         if (dev_hard_header(send_skb, skb->dev, ETH_P_ARP,
 615                                             sha, np->dev->dev_addr,
 616                                             send_skb->len) < 0) {
 617                                 kfree_skb(send_skb);
 618                                 continue;
 619                         }
 620
 621                         /*
 622                          * Fill out the arp protocol part.
 623                          *
 624                          * we only support ethernet device type,
 625                          * which (according to RFC 1390) should
 626                          * always equal 1 (Ethernet).
 627                          */
 628
 629                         arp->ar_hrd = htons(np->dev->type);
 630                         arp->ar_pro = htons(ETH_P_IP);
 631                         arp->ar_hln = np->dev->addr_len;
 632                         arp->ar_pln = 4;
 633                         arp->ar_op = htons(type);
 634
 635                         arp_ptr = (unsigned char *)(arp + 1);
 636                         memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
 637                         arp_ptr += np->dev->addr_len;
 638                         memcpy(arp_ptr, &tip, 4);
 639                         arp_ptr += 4;
 640                         memcpy(arp_ptr, sha, np->dev->addr_len);
 641                         arp_ptr += np->dev->addr_len;
 642                         memcpy(arp_ptr, &sip, 4);
 643
 644                         netpoll_send_skb(np, send_skb);
 645
 646                         /* If there are several rx_skb_hooks for the same
 647                          * address we're fine by sending a single reply
 648                          */
 649                         break;
 650                 }
 651                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 652         } else if( proto == ETH_P_IPV6) {
 653 #if IS_ENABLED(CONFIG_IPV6)
 654                 struct nd_msg *msg;
 655                 u8 *lladdr = NULL;
 656                 struct ipv6hdr *hdr;
 657                 struct icmp6hdr *icmp6h;
 658                 const struct in6_addr *saddr;
 659                 const struct in6_addr *daddr;
 660                 struct inet6_dev *in6_dev = NULL;
 661                 struct in6_addr *target;
 662
 663                 in6_dev = in6_dev_get(skb->dev);
 664                 if (!in6_dev || !in6_dev->cnf.accept_ra)
 665                         return;
 666
 667                 if (!pskb_may_pull(skb, skb->len))
 668                         return;
 669
 670                 msg = (struct nd_msg *)skb_transport_header(skb);
 671
 672                 __skb_push(skb, skb->data - skb_transport_header(skb));
 673
 674                 if (ipv6_hdr(skb)->hop_limit != 255)
 675                         return;
 676                 if (msg->icmph.icmp6_code != 0)
 677                         return;
 678                 if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 679                         return;
 680
 681                 saddr = &ipv6_hdr(skb)->saddr;
 682                 daddr = &ipv6_hdr(skb)->daddr;
 683
 684                 size = sizeof(struct icmp6hdr) + sizeof(struct in6_addr);
 685
 686                 spin_lock_irqsave(&npinfo->rx_lock, flags);
 687                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 688                         if (!ipv6_addr_equal(daddr, &np->local_ip.in6))
 689                                 continue;
 690
 691                         hlen = LL_RESERVED_SPACE(np->dev);
 692                         tlen = np->dev->needed_tailroom;
 693                         send_skb = find_skb(np, size + hlen + tlen, hlen);
 694                         if (!send_skb)
 695                                 continue;
 696
 697                         send_skb->protocol = htons(ETH_P_IPV6);
 698                         send_skb->dev = skb->dev;
 699
 700                         skb_reset_network_header(send_skb);
 701                         hdr = (struct ipv6hdr *) skb_put(send_skb, sizeof(struct ipv6hdr));
 702                         *(__be32*)hdr = htonl(0x60000000);
 703                         hdr->payload_len = htons(size);
 704                         hdr->nexthdr = IPPROTO_ICMPV6;
 705                         hdr->hop_limit = 255;
 706                         hdr->saddr = *saddr;
 707                         hdr->daddr = *daddr;
 708
 709                         icmp6h = (struct icmp6hdr *) skb_put(send_skb, sizeof(struct icmp6hdr));
 710                         icmp6h->icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
 711                         icmp6h->icmp6_router = 0;
 712                         icmp6h->icmp6_solicited = 1;
 713
 714                         target = (struct in6_addr *) skb_put(send_skb, sizeof(struct in6_addr));
 715                         *target = msg->target;
 716                         icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, size,
 717                                                               IPPROTO_ICMPV6,
 718                                                               csum_partial(icmp6h,
 719                                                                            size, 0));
 720
 721                         if (dev_hard_header(send_skb, skb->dev, ETH_P_IPV6,
 722                                             lladdr, np->dev->dev_addr,
 723                                             send_skb->len) < 0) {
 724                                 kfree_skb(send_skb);
 725                                 continue;
 726                         }
 727
 728                         netpoll_send_skb(np, send_skb);
 729
 730                         /* If there are several rx_skb_hooks for the same
 731                          * address, we're fine by sending a single reply
 732                          */
 733                         break;
 734                 }
 735                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 736 #endif
 737         }
 738 }
 739
 740 static bool pkt_is_ns(struct sk_buff *skb)
 741 {
 742         struct nd_msg *msg;
 743         struct ipv6hdr *hdr;
 744
 745         if (skb->protocol != htons(ETH_P_ARP))
 746                 return false;
 747         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + sizeof(struct nd_msg)))
 748                 return false;
 749
 750         msg = (struct nd_msg *)skb_transport_header(skb);
 751         __skb_push(skb, skb->data - skb_transport_header(skb));
 752         hdr = ipv6_hdr(skb);
 753
 754         if (hdr->nexthdr != IPPROTO_ICMPV6)
 755                 return false;
 756         if (hdr->hop_limit != 255)
 757                 return false;
 758         if (msg->icmph.icmp6_code != 0)
 759                 return false;
 760         if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
 761                 return false;
 762
 763         return true;
 764 }
 765
 766 int __netpoll_rx(struct sk_buff *skb, struct netpoll_info *npinfo)
 767 {
 768         int proto, len, ulen, data_len;
 769         int hits = 0, offset;
 770         const struct iphdr *iph;
 771         struct udphdr *uh;
 772         struct netpoll *np, *tmp;
 773         uint16_t source;
 774
 775         if (list_empty(&npinfo->rx_np))
 776                 goto out;
 777
 778         if (skb->dev->type != ARPHRD_ETHER)
 779                 goto out;
 780
 781         /* check if netpoll clients need ARP */
 782         if (skb->protocol == htons(ETH_P_ARP) && atomic_read(&trapped)) {
 783                 skb_queue_tail(&npinfo->neigh_tx, skb);
 784                 return 1;
 785         } else if (pkt_is_ns(skb) && atomic_read(&trapped)) {
 786                 skb_queue_tail(&npinfo->neigh_tx, skb);
 787                 return 1;
 788         }
 789
 790         if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
 791                 skb = vlan_untag(skb);
 792                 if (unlikely(!skb))
 793                         goto out;
 794         }
 795
 796         proto = ntohs(eth_hdr(skb)->h_proto);
 797         if (proto != ETH_P_IP && proto != ETH_P_IPV6)
 798                 goto out;
 799         if (skb->pkt_type == PACKET_OTHERHOST)
 800                 goto out;
 801         if (skb_shared(skb))
 802                 goto out;
 803
 804         if (proto == ETH_P_IP) {
 805                 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 806                         goto out;
 807                 iph = (struct iphdr *)skb->data;
 808                 if (iph->ihl < 5 || iph->version != 4)
 809                         goto out;
 810                 if (!pskb_may_pull(skb, iph->ihl*4))
 811                         goto out;
 812                 iph = (struct iphdr *)skb->data;
 813                 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
 814                         goto out;
 815
 816                 len = ntohs(iph->tot_len);
 817                 if (skb->len < len || len < iph->ihl*4)
 818                         goto out;
 819
 820                 /*
 821                  * Our transport medium may have padded the buffer out.
 822                  * Now We trim to the true length of the frame.
 823                  */
 824                 if (pskb_trim_rcsum(skb, len))
 825                         goto out;
 826
 827                 iph = (struct iphdr *)skb->data;
 828                 if (iph->protocol != IPPROTO_UDP)
 829                         goto out;
 830
 831                 len -= iph->ihl*4;
 832                 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
 833                 offset = (unsigned char *)(uh + 1) - skb->data;
 834                 ulen = ntohs(uh->len);
 835                 data_len = skb->len - offset;
 836                 source = ntohs(uh->source);
 837
 838                 if (ulen != len)
 839                         goto out;
 840                 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
 841                         goto out;
 842                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 843                         if (np->local_ip.ip && np->local_ip.ip != iph->daddr)
 844                                 continue;
 845                         if (np->remote_ip.ip && np->remote_ip.ip != iph->saddr)
 846                                 continue;
 847                         if (np->local_port && np->local_port != ntohs(uh->dest))
 848                                 continue;
 849
 850                         np->rx_skb_hook(np, source, skb, offset, data_len);
 851                         hits++;
 852                 }
 853         } else {
 854 #if IS_ENABLED(CONFIG_IPV6)
 855                 const struct ipv6hdr *ip6h;
 856
 857                 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 858                         goto out;
 859                 ip6h = (struct ipv6hdr *)skb->data;
 860                 if (ip6h->version != 6)
 861                         goto out;
 862                 len = ntohs(ip6h->payload_len);
 863                 if (!len)
 864                         goto out;
 865                 if (len + sizeof(struct ipv6hdr) > skb->len)
 866                         goto out;
 867                 if (pskb_trim_rcsum(skb, len + sizeof(struct ipv6hdr)))
 868                         goto out;
 869                 ip6h = ipv6_hdr(skb);
 870                 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 871                         goto out;
 872                 uh = udp_hdr(skb);
 873                 offset = (unsigned char *)(uh + 1) - skb->data;
 874                 ulen = ntohs(uh->len);
 875                 data_len = skb->len - offset;
 876                 source = ntohs(uh->source);
 877                 if (ulen != skb->len)
 878                         goto out;
 879                 if (udp6_csum_init(skb, uh, IPPROTO_UDP))
 880                         goto out;
 881                 list_for_each_entry_safe(np, tmp, &npinfo->rx_np, rx) {
 882                         if (!ipv6_addr_equal(&np->local_ip.in6, &ip6h->daddr))
 883                                 continue;
 884                         if (!ipv6_addr_equal(&np->remote_ip.in6, &ip6h->saddr))
 885                                 continue;
 886                         if (np->local_port && np->local_port != ntohs(uh->dest))
 887                                 continue;
 888
 889                         np->rx_skb_hook(np, source, skb, offset, data_len);
 890                         hits++;
 891                 }
 892 #endif
 893         }
 894
 895         if (!hits)
 896                 goto out;
 897
 898         kfree_skb(skb);
 899         return 1;
 900
 901 out:
 902         if (atomic_read(&trapped)) {
 903                 kfree_skb(skb);
 904                 return 1;
 905         }
 906
 907         return 0;
 908 }
 909
 910 void netpoll_print_options(struct netpoll *np)
 911 {
 912         np_info(np, "local port %d\n", np->local_port);
 913         if (np->ipv6)
 914                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 915         else
 916                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 917         np_info(np, "interface '%s'\n", np->dev_name);
 918         np_info(np, "remote port %d\n", np->remote_port);
 919         if (np->ipv6)
 920                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 921         else
 922                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 923         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 924 }
 925 EXPORT_SYMBOL(netpoll_print_options);
 926
 927 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 928 {
 929         const char *end;
 930
 931         if (!strchr(str, ':') &&
 932             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 933                 if (!*end)
 934                         return 0;
 935         }
 936         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 937 #if IS_ENABLED(CONFIG_IPV6)
 938                 if (!*end)
 939                         return 1;
 940 #else
 941                 return -1;
 942 #endif
 943         }
 944         return -1;
 945 }
 946
 947 int netpoll_parse_options(struct netpoll *np, char *opt)
 948 {
 949         char *cur=opt, *delim;
 950         int ipv6;
 951
 952         if (*cur != '@') {
 953                 if ((delim = strchr(cur, '@')) == NULL)
 954                         goto parse_failed;
 955                 *delim = 0;
 956                 if (kstrtou16(cur, 10, &np->local_port))
 957                         goto parse_failed;
 958                 cur = delim;
 959         }
 960         cur++;
 961
 962         if (*cur != '/') {
 963                 if ((delim = strchr(cur, '/')) == NULL)
 964                         goto parse_failed;
 965                 *delim = 0;
 966                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 967                 if (ipv6 < 0)
 968                         goto parse_failed;
 969                 else
 970                         np->ipv6 = (bool)ipv6;
 971                 cur = delim;
 972         }
 973         cur++;
 974
 975         if (*cur != ',') {
 976                 /* parse out dev name */
 977                 if ((delim = strchr(cur, ',')) == NULL)
 978                         goto parse_failed;
 979                 *delim = 0;
 980                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 981                 cur = delim;
 982         }
 983         cur++;
 984
 985         if (*cur != '@') {
 986                 /* dst port */
 987                 if ((delim = strchr(cur, '@')) == NULL)
 988                         goto parse_failed;
 989                 *delim = 0;
 990                 if (*cur == ' ' || *cur == '\t')
 991                         np_info(np, "warning: whitespace is not allowed\n");
 992                 if (kstrtou16(cur, 10, &np->remote_port))
 993                         goto parse_failed;
 994                 cur = delim;
 995         }
 996         cur++;
 997
 998         /* dst ip */
 999         if ((delim = strchr(cur, '/')) == NULL)
1000                 goto parse_failed;
1001         *delim = 0;
1002         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
1003         if (ipv6 < 0)
1004                 goto parse_failed;
1005         else if (np->ipv6 != (bool)ipv6)
1006                 goto parse_failed;
1007         else
1008                 np->ipv6 = (bool)ipv6;
1009         cur = delim + 1;
1010
1011         if (*cur != 0) {
1012                 /* MAC address */
1013                 if (!mac_pton(cur, np->remote_mac))
1014                         goto parse_failed;
1015         }
1016
1017         netpoll_print_options(np);
1018
1019         return 0;
1020
1021  parse_failed:
1022         np_info(np, "couldn't parse config at '%s'!\n", cur);
1023         return -1;
1024 }
1025 EXPORT_SYMBOL(netpoll_parse_options);
1026
1027 int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
1028 {
1029         struct netpoll_info *npinfo;
1030         const struct net_device_ops *ops;
1031         unsigned long flags;
1032         int err;
1033
1034         np->dev = ndev;
1035         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
1036         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
1037
1038         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
1039             !ndev->netdev_ops->ndo_poll_controller) {
1040                 np_err(np, "%s doesn't support polling, aborting\n",
1041                        np->dev_name);
1042                 err = -ENOTSUPP;
1043                 goto out;
1044         }
1045
1046         if (!ndev->npinfo) {
1047                 npinfo = kmalloc(sizeof(*npinfo), gfp);
1048                 if (!npinfo) {
1049                         err = -ENOMEM;
1050                         goto out;
1051                 }
1052
1053                 npinfo->rx_flags = 0;
1054                 INIT_LIST_HEAD(&npinfo->rx_np);
1055
1056                 spin_lock_init(&npinfo->rx_lock);
1057                 sema_init(&npinfo->dev_lock, 1);
1058                 skb_queue_head_init(&npinfo->neigh_tx);
1059                 skb_queue_head_init(&npinfo->txq);
1060                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
1061
1062                 atomic_set(&npinfo->refcnt, 1);
1063
1064                 ops = np->dev->netdev_ops;
1065                 if (ops->ndo_netpoll_setup) {
1066                         err = ops->ndo_netpoll_setup(ndev, npinfo, gfp);
1067                         if (err)
1068                                 goto free_npinfo;
1069                 }
1070         } else {
1071                 npinfo = rtnl_dereference(ndev->npinfo);
1072                 atomic_inc(&npinfo->refcnt);
1073         }
1074
1075         npinfo->netpoll = np;
1076
1077         if (np->rx_skb_hook) {
1078                 spin_lock_irqsave(&npinfo->rx_lock, flags);
1079                 npinfo->rx_flags |= NETPOLL_RX_ENABLED;
1080                 list_add_tail(&np->rx, &npinfo->rx_np);
1081                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1082         }
1083
1084         /* last thing to do is link it to the net device structure */
1085         rcu_assign_pointer(ndev->npinfo, npinfo);
1086
1087         return 0;
1088
1089 free_npinfo:
1090         kfree(npinfo);
1091 out:
1092         return err;
1093 }
1094 EXPORT_SYMBOL_GPL(__netpoll_setup);
1095
1096 int netpoll_setup(struct netpoll *np)
1097 {
1098         struct net_device *ndev = NULL;
1099         struct in_device *in_dev;
1100         int err;
1101
1102         rtnl_lock();
1103         if (np->dev_name) {
1104                 struct net *net = current->nsproxy->net_ns;
1105                 ndev = __dev_get_by_name(net, np->dev_name);
1106         }
1107         if (!ndev) {
1108                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
1109                 err = -ENODEV;
1110                 goto unlock;
1111         }
1112         dev_hold(ndev);
1113
1114         if (netdev_master_upper_dev_get(ndev)) {
1115                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
1116                 err = -EBUSY;
1117                 goto put;
1118         }
1119
1120         if (!netif_running(ndev)) {
1121                 unsigned long atmost, atleast;
1122
1123                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
1124
1125                 err = dev_open(ndev);
1126
1127                 if (err) {
1128                         np_err(np, "failed to open %s\n", ndev->name);
1129                         goto put;
1130                 }
1131
1132                 rtnl_unlock();
1133                 atleast = jiffies + HZ/10;
1134                 atmost = jiffies + carrier_timeout * HZ;
1135                 while (!netif_carrier_ok(ndev)) {
1136                         if (time_after(jiffies, atmost)) {
1137                                 np_notice(np, "timeout waiting for carrier\n");
1138                                 break;
1139                         }
1140                         msleep(1);
1141                 }
1142
1143                 /* If carrier appears to come up instantly, we don't
1144                  * trust it and pause so that we don't pump all our
1145                  * queued console messages into the bitbucket.
1146                  */
1147
1148                 if (time_before(jiffies, atleast)) {
1149                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
1150                         msleep(4000);
1151                 }
1152                 rtnl_lock();
1153         }
1154
1155         if (!np->local_ip.ip) {
1156                 if (!np->ipv6) {
1157                         in_dev = __in_dev_get_rtnl(ndev);
1158
1159                         if (!in_dev || !in_dev->ifa_list) {
1160                                 np_err(np, "no IP address for %s, aborting\n",
1161                                        np->dev_name);
1162                                 err = -EDESTADDRREQ;
1163                                 goto put;
1164                         }
1165
1166                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
1167                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
1168                 } else {
1169 #if IS_ENABLED(CONFIG_IPV6)
1170                         struct inet6_dev *idev;
1171
1172                         err = -EDESTADDRREQ;
1173                         idev = __in6_dev_get(ndev);
1174                         if (idev) {
1175                                 struct inet6_ifaddr *ifp;
1176
1177                                 read_lock_bh(&idev->lock);
1178                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
1179                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
1180                                                 continue;
1181                                         np->local_ip.in6 = ifp->addr;
1182                                         err = 0;
1183                                         break;
1184                                 }
1185                                 read_unlock_bh(&idev->lock);
1186                         }
1187                         if (err) {
1188                                 np_err(np, "no IPv6 address for %s, aborting\n",
1189                                        np->dev_name);
1190                                 goto put;
1191                         } else
1192                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
1193 #else
1194                         np_err(np, "IPv6 is not supported %s, aborting\n",
1195                                np->dev_name);
1196                         err = -EINVAL;
1197                         goto put;
1198 #endif
1199                 }
1200         }
1201
1202         /* fill up the skb queue */
1203         refill_skbs();
1204
1205         err = __netpoll_setup(np, ndev, GFP_KERNEL);
1206         if (err)
1207                 goto put;
1208
1209         rtnl_unlock();
1210         return 0;
1211
1212 put:
1213         dev_put(ndev);
1214 unlock:
1215         rtnl_unlock();
1216         return err;
1217 }
1218 EXPORT_SYMBOL(netpoll_setup);
1219
1220 static int __init netpoll_init(void)
1221 {
1222         skb_queue_head_init(&skb_pool);
1223         return 0;
1224 }
1225 core_initcall(netpoll_init);
1226
1227 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
1228 {
1229         struct netpoll_info *npinfo =
1230                         container_of(rcu_head, struct netpoll_info, rcu);
1231
1232         skb_queue_purge(&npinfo->neigh_tx);
1233         skb_queue_purge(&npinfo->txq);
1234
1235         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
1236         cancel_delayed_work(&npinfo->tx_work);
1237
1238         /* clean after last, unfinished work */
1239         __skb_queue_purge(&npinfo->txq);
1240         /* now cancel it again */
1241         cancel_delayed_work(&npinfo->tx_work);
1242         kfree(npinfo);
1243 }
1244
1245 void __netpoll_cleanup(struct netpoll *np)
1246 {
1247         struct netpoll_info *npinfo;
1248         unsigned long flags;
1249
1250         /* rtnl_dereference would be preferable here but
1251          * rcu_cleanup_netpoll path can put us in here safely without
1252          * holding the rtnl, so plain rcu_dereference it is
1253          */
1254         npinfo = rtnl_dereference(np->dev->npinfo);
1255         if (!npinfo)
1256                 return;
1257
1258         if (!list_empty(&npinfo->rx_np)) {
1259                 spin_lock_irqsave(&npinfo->rx_lock, flags);
1260                 list_del(&np->rx);
1261                 if (list_empty(&npinfo->rx_np))
1262                         npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
1263                 spin_unlock_irqrestore(&npinfo->rx_lock, flags);
1264         }
1265
1266         synchronize_srcu(&netpoll_srcu);
1267
1268         if (atomic_dec_and_test(&npinfo->refcnt)) {
1269                 const struct net_device_ops *ops;
1270
1271                 ops = np->dev->netdev_ops;
1272                 if (ops->ndo_netpoll_cleanup)
1273                         ops->ndo_netpoll_cleanup(np->dev);
1274
1275                 rcu_assign_pointer(np->dev->npinfo, NULL);
1276                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
1277         }
1278 }
1279 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
1280
1281 static void netpoll_async_cleanup(struct work_struct *work)
1282 {
1283         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
1284
1285         rtnl_lock();
1286         __netpoll_cleanup(np);
1287         rtnl_unlock();
1288         kfree(np);
1289 }
1290
1291 void __netpoll_free_async(struct netpoll *np)
1292 {
1293         schedule_work(&np->cleanup_work);
1294 }
1295 EXPORT_SYMBOL_GPL(__netpoll_free_async);
1296
1297 void netpoll_cleanup(struct netpoll *np)
1298 {
1299         rtnl_lock();
1300         if (!np->dev)
1301                 goto out;
1302         __netpoll_cleanup(np);
1303         dev_put(np->dev);
1304         np->dev = NULL;
1305 out:
1306         rtnl_unlock();
1307 }
1308 EXPORT_SYMBOL(netpoll_cleanup);
1309
1310 int netpoll_trap(void)
1311 {
1312         return atomic_read(&trapped);
1313 }
1314 EXPORT_SYMBOL(netpoll_trap);
1315
1316 void netpoll_set_trap(int trap)
1317 {
1318         if (trap)
1319                 atomic_inc(&trapped);
1320         else
1321                 atomic_dec(&trapped);
1322 }
1323 EXPORT_SYMBOL(netpoll_set_trap);