net/core/netpoll.c

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