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 DEFINE_STATIC_SRCU(netpoll_srcu);
  50
  51 #define USEC_PER_POLL   50
  52
  53 #define MAX_SKB_SIZE                                                    \
  54         (sizeof(struct ethhdr) +                                        \
  55          sizeof(struct iphdr) +                                         \
  56          sizeof(struct udphdr) +                                        \
  57          MAX_UDP_CHUNK)
  58
  59 static void zap_completion_queue(void);
  60 static void netpoll_async_cleanup(struct work_struct *work);
  61
  62 static unsigned int carrier_timeout = 4;
  63 module_param(carrier_timeout, uint, 0644);
  64
  65 #define np_info(np, fmt, ...)                           \
  66         pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
  67 #define np_err(np, fmt, ...)                            \
  68         pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
  69 #define np_notice(np, fmt, ...)                         \
  70         pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
  71
  72 static void queue_process(struct work_struct *work)
  73 {
  74         struct netpoll_info *npinfo =
  75                 container_of(work, struct netpoll_info, tx_work.work);
  76         struct sk_buff *skb;
  77         unsigned long flags;
  78
  79         while ((skb = skb_dequeue(&npinfo->txq))) {
  80                 struct net_device *dev = skb->dev;
  81                 const struct net_device_ops *ops = dev->netdev_ops;
  82                 struct netdev_queue *txq;
  83
  84                 if (!netif_device_present(dev) || !netif_running(dev)) {
  85                         __kfree_skb(skb);
  86                         continue;
  87                 }
  88
  89                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
  90
  91                 local_irq_save(flags);
  92                 __netif_tx_lock(txq, smp_processor_id());
  93                 if (netif_xmit_frozen_or_stopped(txq) ||
  94                     ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
  95                         skb_queue_head(&npinfo->txq, skb);
  96                         __netif_tx_unlock(txq);
  97                         local_irq_restore(flags);
  98
  99                         schedule_delayed_work(&npinfo->tx_work, HZ/10);
 100                         return;
 101                 }
 102                 __netif_tx_unlock(txq);
 103                 local_irq_restore(flags);
 104         }
 105 }
 106
 107 /*
 108  * Check whether delayed processing was scheduled for our NIC. If so,
 109  * we attempt to grab the poll lock and use ->poll() to pump the card.
 110  * If this fails, either we've recursed in ->poll() or it's already
 111  * running on another CPU.
 112  *
 113  * Note: we don't mask interrupts with this lock because we're using
 114  * trylock here and interrupts are already disabled in the softirq
 115  * case. Further, we test the poll_owner to avoid recursion on UP
 116  * systems where the lock doesn't exist.
 117  */
 118 static int poll_one_napi(struct napi_struct *napi, int budget)
 119 {
 120         int work;
 121
 122         /* net_rx_action's ->poll() invocations and our's are
 123          * synchronized by this test which is only made while
 124          * holding the napi->poll_lock.
 125          */
 126         if (!test_bit(NAPI_STATE_SCHED, &napi->state))
 127                 return budget;
 128
 129         set_bit(NAPI_STATE_NPSVC, &napi->state);
 130
 131         work = napi->poll(napi, budget);
 132         WARN_ONCE(work > budget, "%pF exceeded budget in poll\n", napi->poll);
 133         trace_napi_poll(napi);
 134
 135         clear_bit(NAPI_STATE_NPSVC, &napi->state);
 136
 137         return budget - work;
 138 }
 139
 140 static void poll_napi(struct net_device *dev, int budget)
 141 {
 142         struct napi_struct *napi;
 143
 144         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 145                 if (napi->poll_owner != smp_processor_id() &&
 146                     spin_trylock(&napi->poll_lock)) {
 147                         budget = poll_one_napi(napi, budget);
 148                         spin_unlock(&napi->poll_lock);
 149                 }
 150         }
 151 }
 152
 153 static void netpoll_poll_dev(struct net_device *dev)
 154 {
 155         const struct net_device_ops *ops;
 156         struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
 157         int budget = 0;
 158
 159         /* Don't do any rx activity if the dev_lock mutex is held
 160          * the dev_open/close paths use this to block netpoll activity
 161          * while changing device state
 162          */
 163         if (down_trylock(&ni->dev_lock))
 164                 return;
 165
 166         if (!netif_running(dev)) {
 167                 up(&ni->dev_lock);
 168                 return;
 169         }
 170
 171         ops = dev->netdev_ops;
 172         if (!ops->ndo_poll_controller) {
 173                 up(&ni->dev_lock);
 174                 return;
 175         }
 176
 177         /* Process pending work on NIC */
 178         ops->ndo_poll_controller(dev);
 179
 180         poll_napi(dev, budget);
 181
 182         up(&ni->dev_lock);
 183
 184         zap_completion_queue();
 185 }
 186
 187 void netpoll_rx_disable(struct net_device *dev)
 188 {
 189         struct netpoll_info *ni;
 190         int idx;
 191         might_sleep();
 192         idx = srcu_read_lock(&netpoll_srcu);
 193         ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
 194         if (ni)
 195                 down(&ni->dev_lock);
 196         srcu_read_unlock(&netpoll_srcu, idx);
 197 }
 198 EXPORT_SYMBOL(netpoll_rx_disable);
 199
 200 void netpoll_rx_enable(struct net_device *dev)
 201 {
 202         struct netpoll_info *ni;
 203         rcu_read_lock();
 204         ni = rcu_dereference(dev->npinfo);
 205         if (ni)
 206                 up(&ni->dev_lock);
 207         rcu_read_unlock();
 208 }
 209 EXPORT_SYMBOL(netpoll_rx_enable);
 210
 211 static void refill_skbs(void)
 212 {
 213         struct sk_buff *skb;
 214         unsigned long flags;
 215
 216         spin_lock_irqsave(&skb_pool.lock, flags);
 217         while (skb_pool.qlen < MAX_SKBS) {
 218                 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 219                 if (!skb)
 220                         break;
 221
 222                 __skb_queue_tail(&skb_pool, skb);
 223         }
 224         spin_unlock_irqrestore(&skb_pool.lock, flags);
 225 }
 226
 227 static void zap_completion_queue(void)
 228 {
 229         unsigned long flags;
 230         struct softnet_data *sd = &get_cpu_var(softnet_data);
 231
 232         if (sd->completion_queue) {
 233                 struct sk_buff *clist;
 234
 235                 local_irq_save(flags);
 236                 clist = sd->completion_queue;
 237                 sd->completion_queue = NULL;
 238                 local_irq_restore(flags);
 239
 240                 while (clist != NULL) {
 241                         struct sk_buff *skb = clist;
 242                         clist = clist->next;
 243                         if (skb->destructor) {
 244                                 atomic_inc(&skb->users);
 245                                 dev_kfree_skb_any(skb); /* put this one back */
 246                         } else {
 247                                 __kfree_skb(skb);
 248                         }
 249                 }
 250         }
 251
 252         put_cpu_var(softnet_data);
 253 }
 254
 255 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 256 {
 257         int count = 0;
 258         struct sk_buff *skb;
 259
 260         zap_completion_queue();
 261         refill_skbs();
 262 repeat:
 263
 264         skb = alloc_skb(len, GFP_ATOMIC);
 265         if (!skb)
 266                 skb = skb_dequeue(&skb_pool);
 267
 268         if (!skb) {
 269                 if (++count < 10) {
 270                         netpoll_poll_dev(np->dev);
 271                         goto repeat;
 272                 }
 273                 return NULL;
 274         }
 275
 276         atomic_set(&skb->users, 1);
 277         skb_reserve(skb, reserve);
 278         return skb;
 279 }
 280
 281 static int netpoll_owner_active(struct net_device *dev)
 282 {
 283         struct napi_struct *napi;
 284
 285         list_for_each_entry(napi, &dev->napi_list, dev_list) {
 286                 if (napi->poll_owner == smp_processor_id())
 287                         return 1;
 288         }
 289         return 0;
 290 }
 291
 292 /* call with IRQ disabled */
 293 void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 294                              struct net_device *dev)
 295 {
 296         int status = NETDEV_TX_BUSY;
 297         unsigned long tries;
 298         const struct net_device_ops *ops = dev->netdev_ops;
 299         /* It is up to the caller to keep npinfo alive. */
 300         struct netpoll_info *npinfo;
 301
 302         WARN_ON_ONCE(!irqs_disabled());
 303
 304         npinfo = rcu_dereference_bh(np->dev->npinfo);
 305         if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 306                 __kfree_skb(skb);
 307                 return;
 308         }
 309
 310         /* don't get messages out of order, and no recursion */
 311         if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
 312                 struct netdev_queue *txq;
 313
 314                 txq = netdev_pick_tx(dev, skb, NULL);
 315
 316                 /* try until next clock tick */
 317                 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
 318                      tries > 0; --tries) {
 319                         if (__netif_tx_trylock(txq)) {
 320                                 if (!netif_xmit_stopped(txq)) {
 321                                         if (vlan_tx_tag_present(skb) &&
 322                                             !vlan_hw_offload_capable(netif_skb_features(skb),
 323                                                                      skb->vlan_proto)) {
 324                                                 skb = __vlan_put_tag(skb, skb->vlan_proto, vlan_tx_tag_get(skb));
 325                                                 if (unlikely(!skb)) {
 326                                                         /* This is actually a packet drop, but we
 327                                                          * don't want the code at the end of this
 328                                                          * function to try and re-queue a NULL skb.
 329                                                          */
 330                                                         status = NETDEV_TX_OK;
 331                                                         goto unlock_txq;
 332                                                 }
 333                                                 skb->vlan_tci = 0;
 334                                         }
 335
 336                                         status = ops->ndo_start_xmit(skb, dev);
 337                                         if (status == NETDEV_TX_OK)
 338                                                 txq_trans_update(txq);
 339                                 }
 340                         unlock_txq:
 341                                 __netif_tx_unlock(txq);
 342
 343                                 if (status == NETDEV_TX_OK)
 344                                         break;
 345
 346                         }
 347
 348                         /* tickle device maybe there is some cleanup */
 349                         netpoll_poll_dev(np->dev);
 350
 351                         udelay(USEC_PER_POLL);
 352                 }
 353
 354                 WARN_ONCE(!irqs_disabled(),
 355                         "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
 356                         dev->name, ops->ndo_start_xmit);
 357
 358         }
 359
 360         if (status != NETDEV_TX_OK) {
 361                 skb_queue_tail(&npinfo->txq, skb);
 362                 schedule_delayed_work(&npinfo->tx_work,0);
 363         }
 364 }
 365 EXPORT_SYMBOL(netpoll_send_skb_on_dev);
 366
 367 void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 368 {
 369         int total_len, ip_len, udp_len;
 370         struct sk_buff *skb;
 371         struct udphdr *udph;
 372         struct iphdr *iph;
 373         struct ethhdr *eth;
 374         static atomic_t ip_ident;
 375         struct ipv6hdr *ip6h;
 376
 377         udp_len = len + sizeof(*udph);
 378         if (np->ipv6)
 379                 ip_len = udp_len + sizeof(*ip6h);
 380         else
 381                 ip_len = udp_len + sizeof(*iph);
 382
 383         total_len = ip_len + LL_RESERVED_SPACE(np->dev);
 384
 385         skb = find_skb(np, total_len + np->dev->needed_tailroom,
 386                        total_len - len);
 387         if (!skb)
 388                 return;
 389
 390         skb_copy_to_linear_data(skb, msg, len);
 391         skb_put(skb, len);
 392
 393         skb_push(skb, sizeof(*udph));
 394         skb_reset_transport_header(skb);
 395         udph = udp_hdr(skb);
 396         udph->source = htons(np->local_port);
 397         udph->dest = htons(np->remote_port);
 398         udph->len = htons(udp_len);
 399
 400         if (np->ipv6) {
 401                 udph->check = 0;
 402                 udph->check = csum_ipv6_magic(&np->local_ip.in6,
 403                                               &np->remote_ip.in6,
 404                                               udp_len, IPPROTO_UDP,
 405                                               csum_partial(udph, udp_len, 0));
 406                 if (udph->check == 0)
 407                         udph->check = CSUM_MANGLED_0;
 408
 409                 skb_push(skb, sizeof(*ip6h));
 410                 skb_reset_network_header(skb);
 411                 ip6h = ipv6_hdr(skb);
 412
 413                 /* ip6h->version = 6; ip6h->priority = 0; */
 414                 put_unaligned(0x60, (unsigned char *)ip6h);
 415                 ip6h->flow_lbl[0] = 0;
 416                 ip6h->flow_lbl[1] = 0;
 417                 ip6h->flow_lbl[2] = 0;
 418
 419                 ip6h->payload_len = htons(sizeof(struct udphdr) + len);
 420                 ip6h->nexthdr = IPPROTO_UDP;
 421                 ip6h->hop_limit = 32;
 422                 ip6h->saddr = np->local_ip.in6;
 423                 ip6h->daddr = np->remote_ip.in6;
 424
 425                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 426                 skb_reset_mac_header(skb);
 427                 skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
 428         } else {
 429                 udph->check = 0;
 430                 udph->check = csum_tcpudp_magic(np->local_ip.ip,
 431                                                 np->remote_ip.ip,
 432                                                 udp_len, IPPROTO_UDP,
 433                                                 csum_partial(udph, udp_len, 0));
 434                 if (udph->check == 0)
 435                         udph->check = CSUM_MANGLED_0;
 436
 437                 skb_push(skb, sizeof(*iph));
 438                 skb_reset_network_header(skb);
 439                 iph = ip_hdr(skb);
 440
 441                 /* iph->version = 4; iph->ihl = 5; */
 442                 put_unaligned(0x45, (unsigned char *)iph);
 443                 iph->tos      = 0;
 444                 put_unaligned(htons(ip_len), &(iph->tot_len));
 445                 iph->id       = htons(atomic_inc_return(&ip_ident));
 446                 iph->frag_off = 0;
 447                 iph->ttl      = 64;
 448                 iph->protocol = IPPROTO_UDP;
 449                 iph->check    = 0;
 450                 put_unaligned(np->local_ip.ip, &(iph->saddr));
 451                 put_unaligned(np->remote_ip.ip, &(iph->daddr));
 452                 iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 453
 454                 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
 455                 skb_reset_mac_header(skb);
 456                 skb->protocol = eth->h_proto = htons(ETH_P_IP);
 457         }
 458
 459         ether_addr_copy(eth->h_source, np->dev->dev_addr);
 460         ether_addr_copy(eth->h_dest, np->remote_mac);
 461
 462         skb->dev = np->dev;
 463
 464         netpoll_send_skb(np, skb);
 465 }
 466 EXPORT_SYMBOL(netpoll_send_udp);
 467
 468 void netpoll_print_options(struct netpoll *np)
 469 {
 470         np_info(np, "local port %d\n", np->local_port);
 471         if (np->ipv6)
 472                 np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
 473         else
 474                 np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
 475         np_info(np, "interface '%s'\n", np->dev_name);
 476         np_info(np, "remote port %d\n", np->remote_port);
 477         if (np->ipv6)
 478                 np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
 479         else
 480                 np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
 481         np_info(np, "remote ethernet address %pM\n", np->remote_mac);
 482 }
 483 EXPORT_SYMBOL(netpoll_print_options);
 484
 485 static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 486 {
 487         const char *end;
 488
 489         if (!strchr(str, ':') &&
 490             in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
 491                 if (!*end)
 492                         return 0;
 493         }
 494         if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
 495 #if IS_ENABLED(CONFIG_IPV6)
 496                 if (!*end)
 497                         return 1;
 498 #else
 499                 return -1;
 500 #endif
 501         }
 502         return -1;
 503 }
 504
 505 int netpoll_parse_options(struct netpoll *np, char *opt)
 506 {
 507         char *cur=opt, *delim;
 508         int ipv6;
 509         bool ipversion_set = false;
 510
 511         if (*cur != '@') {
 512                 if ((delim = strchr(cur, '@')) == NULL)
 513                         goto parse_failed;
 514                 *delim = 0;
 515                 if (kstrtou16(cur, 10, &np->local_port))
 516                         goto parse_failed;
 517                 cur = delim;
 518         }
 519         cur++;
 520
 521         if (*cur != '/') {
 522                 ipversion_set = true;
 523                 if ((delim = strchr(cur, '/')) == NULL)
 524                         goto parse_failed;
 525                 *delim = 0;
 526                 ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
 527                 if (ipv6 < 0)
 528                         goto parse_failed;
 529                 else
 530                         np->ipv6 = (bool)ipv6;
 531                 cur = delim;
 532         }
 533         cur++;
 534
 535         if (*cur != ',') {
 536                 /* parse out dev name */
 537                 if ((delim = strchr(cur, ',')) == NULL)
 538                         goto parse_failed;
 539                 *delim = 0;
 540                 strlcpy(np->dev_name, cur, sizeof(np->dev_name));
 541                 cur = delim;
 542         }
 543         cur++;
 544
 545         if (*cur != '@') {
 546                 /* dst port */
 547                 if ((delim = strchr(cur, '@')) == NULL)
 548                         goto parse_failed;
 549                 *delim = 0;
 550                 if (*cur == ' ' || *cur == '\t')
 551                         np_info(np, "warning: whitespace is not allowed\n");
 552                 if (kstrtou16(cur, 10, &np->remote_port))
 553                         goto parse_failed;
 554                 cur = delim;
 555         }
 556         cur++;
 557
 558         /* dst ip */
 559         if ((delim = strchr(cur, '/')) == NULL)
 560                 goto parse_failed;
 561         *delim = 0;
 562         ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
 563         if (ipv6 < 0)
 564                 goto parse_failed;
 565         else if (ipversion_set && np->ipv6 != (bool)ipv6)
 566                 goto parse_failed;
 567         else
 568                 np->ipv6 = (bool)ipv6;
 569         cur = delim + 1;
 570
 571         if (*cur != 0) {
 572                 /* MAC address */
 573                 if (!mac_pton(cur, np->remote_mac))
 574                         goto parse_failed;
 575         }
 576
 577         netpoll_print_options(np);
 578
 579         return 0;
 580
 581  parse_failed:
 582         np_info(np, "couldn't parse config at '%s'!\n", cur);
 583         return -1;
 584 }
 585 EXPORT_SYMBOL(netpoll_parse_options);
 586
 587 int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
 588 {
 589         struct netpoll_info *npinfo;
 590         const struct net_device_ops *ops;
 591         int err;
 592
 593         np->dev = ndev;
 594         strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
 595         INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
 596
 597         if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
 598             !ndev->netdev_ops->ndo_poll_controller) {
 599                 np_err(np, "%s doesn't support polling, aborting\n",
 600                        np->dev_name);
 601                 err = -ENOTSUPP;
 602                 goto out;
 603         }
 604
 605         if (!ndev->npinfo) {
 606                 npinfo = kmalloc(sizeof(*npinfo), gfp);
 607                 if (!npinfo) {
 608                         err = -ENOMEM;
 609                         goto out;
 610                 }
 611
 612                 sema_init(&npinfo->dev_lock, 1);
 613                 skb_queue_head_init(&npinfo->txq);
 614                 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
 615
 616                 atomic_set(&npinfo->refcnt, 1);
 617
 618                 ops = np->dev->netdev_ops;
 619                 if (ops->ndo_netpoll_setup) {
 620                         err = ops->ndo_netpoll_setup(ndev, npinfo, gfp);
 621                         if (err)
 622                                 goto free_npinfo;
 623                 }
 624         } else {
 625                 npinfo = rtnl_dereference(ndev->npinfo);
 626                 atomic_inc(&npinfo->refcnt);
 627         }
 628
 629         npinfo->netpoll = np;
 630
 631         /* last thing to do is link it to the net device structure */
 632         rcu_assign_pointer(ndev->npinfo, npinfo);
 633
 634         return 0;
 635
 636 free_npinfo:
 637         kfree(npinfo);
 638 out:
 639         return err;
 640 }
 641 EXPORT_SYMBOL_GPL(__netpoll_setup);
 642
 643 int netpoll_setup(struct netpoll *np)
 644 {
 645         struct net_device *ndev = NULL;
 646         struct in_device *in_dev;
 647         int err;
 648
 649         rtnl_lock();
 650         if (np->dev_name) {
 651                 struct net *net = current->nsproxy->net_ns;
 652                 ndev = __dev_get_by_name(net, np->dev_name);
 653         }
 654         if (!ndev) {
 655                 np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
 656                 err = -ENODEV;
 657                 goto unlock;
 658         }
 659         dev_hold(ndev);
 660
 661         if (netdev_master_upper_dev_get(ndev)) {
 662                 np_err(np, "%s is a slave device, aborting\n", np->dev_name);
 663                 err = -EBUSY;
 664                 goto put;
 665         }
 666
 667         if (!netif_running(ndev)) {
 668                 unsigned long atmost, atleast;
 669
 670                 np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
 671
 672                 err = dev_open(ndev);
 673
 674                 if (err) {
 675                         np_err(np, "failed to open %s\n", ndev->name);
 676                         goto put;
 677                 }
 678
 679                 rtnl_unlock();
 680                 atleast = jiffies + HZ/10;
 681                 atmost = jiffies + carrier_timeout * HZ;
 682                 while (!netif_carrier_ok(ndev)) {
 683                         if (time_after(jiffies, atmost)) {
 684                                 np_notice(np, "timeout waiting for carrier\n");
 685                                 break;
 686                         }
 687                         msleep(1);
 688                 }
 689
 690                 /* If carrier appears to come up instantly, we don't
 691                  * trust it and pause so that we don't pump all our
 692                  * queued console messages into the bitbucket.
 693                  */
 694
 695                 if (time_before(jiffies, atleast)) {
 696                         np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
 697                         msleep(4000);
 698                 }
 699                 rtnl_lock();
 700         }
 701
 702         if (!np->local_ip.ip) {
 703                 if (!np->ipv6) {
 704                         in_dev = __in_dev_get_rtnl(ndev);
 705
 706                         if (!in_dev || !in_dev->ifa_list) {
 707                                 np_err(np, "no IP address for %s, aborting\n",
 708                                        np->dev_name);
 709                                 err = -EDESTADDRREQ;
 710                                 goto put;
 711                         }
 712
 713                         np->local_ip.ip = in_dev->ifa_list->ifa_local;
 714                         np_info(np, "local IP %pI4\n", &np->local_ip.ip);
 715                 } else {
 716 #if IS_ENABLED(CONFIG_IPV6)
 717                         struct inet6_dev *idev;
 718
 719                         err = -EDESTADDRREQ;
 720                         idev = __in6_dev_get(ndev);
 721                         if (idev) {
 722                                 struct inet6_ifaddr *ifp;
 723
 724                                 read_lock_bh(&idev->lock);
 725                                 list_for_each_entry(ifp, &idev->addr_list, if_list) {
 726                                         if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
 727                                                 continue;
 728                                         np->local_ip.in6 = ifp->addr;
 729                                         err = 0;
 730                                         break;
 731                                 }
 732                                 read_unlock_bh(&idev->lock);
 733                         }
 734                         if (err) {
 735                                 np_err(np, "no IPv6 address for %s, aborting\n",
 736                                        np->dev_name);
 737                                 goto put;
 738                         } else
 739                                 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
 740 #else
 741                         np_err(np, "IPv6 is not supported %s, aborting\n",
 742                                np->dev_name);
 743                         err = -EINVAL;
 744                         goto put;
 745 #endif
 746                 }
 747         }
 748
 749         /* fill up the skb queue */
 750         refill_skbs();
 751
 752         err = __netpoll_setup(np, ndev, GFP_KERNEL);
 753         if (err)
 754                 goto put;
 755
 756         rtnl_unlock();
 757         return 0;
 758
 759 put:
 760         dev_put(ndev);
 761 unlock:
 762         rtnl_unlock();
 763         return err;
 764 }
 765 EXPORT_SYMBOL(netpoll_setup);
 766
 767 static int __init netpoll_init(void)
 768 {
 769         skb_queue_head_init(&skb_pool);
 770         return 0;
 771 }
 772 core_initcall(netpoll_init);
 773
 774 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 775 {
 776         struct netpoll_info *npinfo =
 777                         container_of(rcu_head, struct netpoll_info, rcu);
 778
 779         skb_queue_purge(&npinfo->txq);
 780
 781         /* we can't call cancel_delayed_work_sync here, as we are in softirq */
 782         cancel_delayed_work(&npinfo->tx_work);
 783
 784         /* clean after last, unfinished work */
 785         __skb_queue_purge(&npinfo->txq);
 786         /* now cancel it again */
 787         cancel_delayed_work(&npinfo->tx_work);
 788         kfree(npinfo);
 789 }
 790
 791 void __netpoll_cleanup(struct netpoll *np)
 792 {
 793         struct netpoll_info *npinfo;
 794
 795         /* rtnl_dereference would be preferable here but
 796          * rcu_cleanup_netpoll path can put us in here safely without
 797          * holding the rtnl, so plain rcu_dereference it is
 798          */
 799         npinfo = rtnl_dereference(np->dev->npinfo);
 800         if (!npinfo)
 801                 return;
 802
 803         synchronize_srcu(&netpoll_srcu);
 804
 805         if (atomic_dec_and_test(&npinfo->refcnt)) {
 806                 const struct net_device_ops *ops;
 807
 808                 ops = np->dev->netdev_ops;
 809                 if (ops->ndo_netpoll_cleanup)
 810                         ops->ndo_netpoll_cleanup(np->dev);
 811
 812                 rcu_assign_pointer(np->dev->npinfo, NULL);
 813                 call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
 814         }
 815 }
 816 EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 817
 818 static void netpoll_async_cleanup(struct work_struct *work)
 819 {
 820         struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
 821
 822         rtnl_lock();
 823         __netpoll_cleanup(np);
 824         rtnl_unlock();
 825         kfree(np);
 826 }
 827
 828 void __netpoll_free_async(struct netpoll *np)
 829 {
 830         schedule_work(&np->cleanup_work);
 831 }
 832 EXPORT_SYMBOL_GPL(__netpoll_free_async);
 833
 834 void netpoll_cleanup(struct netpoll *np)
 835 {
 836         rtnl_lock();
 837         if (!np->dev)
 838                 goto out;
 839         __netpoll_cleanup(np);
 840         dev_put(np->dev);
 841         np->dev = NULL;
 842 out:
 843         rtnl_unlock();
 844 }
 845 EXPORT_SYMBOL(netpoll_cleanup);