1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Common framework for low-level network console, dump, and debugger code 4 * 5 * Sep 8 2003 Matt Mackall <mpm@selenic.com> 6 * 7 * based on the netconsole code from: 8 * 9 * Copyright (C) 2001 Ingo Molnar <mingo@redhat.com> 10 * Copyright (C) 2002 Red Hat, Inc. 11 */ 12 13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 14 15 #include <linux/moduleparam.h> 16 #include <linux/kernel.h> 17 #include <linux/netdevice.h> 18 #include <linux/etherdevice.h> 19 #include <linux/string.h> 20 #include <linux/if_arp.h> 21 #include <linux/inetdevice.h> 22 #include <linux/inet.h> 23 #include <linux/interrupt.h> 24 #include <linux/netpoll.h> 25 #include <linux/sched.h> 26 #include <linux/delay.h> 27 #include <linux/rcupdate.h> 28 #include <linux/workqueue.h> 29 #include <linux/slab.h> 30 #include <linux/export.h> 31 #include <linux/if_vlan.h> 32 #include <net/tcp.h> 33 #include <net/udp.h> 34 #include <net/addrconf.h> 35 #include <net/ndisc.h> 36 #include <net/ip6_checksum.h> 37 #include <linux/unaligned.h> 38 #include <trace/events/napi.h> 39 #include <linux/kconfig.h> 40 41 /* 42 * We maintain a small pool of fully-sized skbs, to make sure the 43 * message gets out even in extreme OOM situations. 44 */ 45 46 #define MAX_UDP_CHUNK 1460 47 #define MAX_SKBS 32 48 #define USEC_PER_POLL 50 49 50 #define MAX_SKB_SIZE \ 51 (sizeof(struct ethhdr) + \ 52 sizeof(struct iphdr) + \ 53 sizeof(struct udphdr) + \ 54 MAX_UDP_CHUNK) 55 56 static void zap_completion_queue(void); 57 58 static unsigned int carrier_timeout = 4; 59 module_param(carrier_timeout, uint, 0644); 60 61 static netdev_tx_t netpoll_start_xmit(struct sk_buff *skb, 62 struct net_device *dev, 63 struct netdev_queue *txq) 64 { 65 netdev_tx_t status = NETDEV_TX_OK; 66 netdev_features_t features; 67 68 features = netif_skb_features(skb); 69 70 if (skb_vlan_tag_present(skb) && 71 !vlan_hw_offload_capable(features, skb->vlan_proto)) { 72 skb = __vlan_hwaccel_push_inside(skb); 73 if (unlikely(!skb)) { 74 /* This is actually a packet drop, but we 75 * don't want the code that calls this 76 * function to try and operate on a NULL skb. 77 */ 78 goto out; 79 } 80 } 81 82 status = netdev_start_xmit(skb, dev, txq, false); 83 84 out: 85 return status; 86 } 87 88 static void queue_process(struct work_struct *work) 89 { 90 struct netpoll_info *npinfo = 91 container_of(work, struct netpoll_info, tx_work.work); 92 struct sk_buff *skb; 93 unsigned long flags; 94 95 while ((skb = skb_dequeue(&npinfo->txq))) { 96 struct net_device *dev = skb->dev; 97 struct netdev_queue *txq; 98 unsigned int q_index; 99 100 if (!netif_device_present(dev) || !netif_running(dev)) { 101 kfree_skb(skb); 102 continue; 103 } 104 105 local_irq_save(flags); 106 /* check if skb->queue_mapping is still valid */ 107 q_index = skb_get_queue_mapping(skb); 108 if (unlikely(q_index >= dev->real_num_tx_queues)) { 109 q_index = q_index % dev->real_num_tx_queues; 110 skb_set_queue_mapping(skb, q_index); 111 } 112 txq = netdev_get_tx_queue(dev, q_index); 113 HARD_TX_LOCK(dev, txq, smp_processor_id()); 114 if (netif_xmit_frozen_or_stopped(txq) || 115 !dev_xmit_complete(netpoll_start_xmit(skb, dev, txq))) { 116 skb_queue_head(&npinfo->txq, skb); 117 HARD_TX_UNLOCK(dev, txq); 118 local_irq_restore(flags); 119 120 schedule_delayed_work(&npinfo->tx_work, HZ/10); 121 return; 122 } 123 HARD_TX_UNLOCK(dev, txq); 124 local_irq_restore(flags); 125 } 126 } 127 128 static int netif_local_xmit_active(struct net_device *dev) 129 { 130 int i; 131 132 for (i = 0; i < dev->num_tx_queues; i++) { 133 struct netdev_queue *txq = netdev_get_tx_queue(dev, i); 134 135 if (READ_ONCE(txq->xmit_lock_owner) == smp_processor_id()) 136 return 1; 137 } 138 139 return 0; 140 } 141 142 static void poll_one_napi(struct napi_struct *napi) 143 { 144 int work; 145 146 /* If we set this bit but see that it has already been set, 147 * that indicates that napi has been disabled and we need 148 * to abort this operation 149 */ 150 if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state)) 151 return; 152 153 /* We explicitly pass the polling call a budget of 0 to 154 * indicate that we are clearing the Tx path only. 155 */ 156 work = napi->poll(napi, 0); 157 WARN_ONCE(work, "%pS exceeded budget in poll\n", napi->poll); 158 trace_napi_poll(napi, work, 0); 159 160 clear_bit(NAPI_STATE_NPSVC, &napi->state); 161 } 162 163 static void poll_napi(struct net_device *dev) 164 { 165 struct napi_struct *napi; 166 int cpu = smp_processor_id(); 167 168 list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) { 169 if (cmpxchg(&napi->poll_owner, -1, cpu) == -1) { 170 poll_one_napi(napi); 171 smp_store_release(&napi->poll_owner, -1); 172 } 173 } 174 } 175 176 void netpoll_poll_dev(struct net_device *dev) 177 { 178 struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo); 179 const struct net_device_ops *ops; 180 181 /* Don't do any rx activity if the dev_lock mutex is held 182 * the dev_open/close paths use this to block netpoll activity 183 * while changing device state 184 */ 185 if (!ni || down_trylock(&ni->dev_lock)) 186 return; 187 188 /* Some drivers will take the same locks in poll and xmit, 189 * we can't poll if local CPU is already in xmit. 190 */ 191 if (!netif_running(dev) || netif_local_xmit_active(dev)) { 192 up(&ni->dev_lock); 193 return; 194 } 195 196 ops = dev->netdev_ops; 197 if (ops->ndo_poll_controller) 198 ops->ndo_poll_controller(dev); 199 200 poll_napi(dev); 201 202 up(&ni->dev_lock); 203 204 zap_completion_queue(); 205 } 206 EXPORT_SYMBOL(netpoll_poll_dev); 207 208 void netpoll_poll_disable(struct net_device *dev) 209 { 210 struct netpoll_info *ni; 211 212 might_sleep(); 213 ni = rtnl_dereference(dev->npinfo); 214 if (ni) 215 down(&ni->dev_lock); 216 } 217 218 void netpoll_poll_enable(struct net_device *dev) 219 { 220 struct netpoll_info *ni; 221 222 ni = rtnl_dereference(dev->npinfo); 223 if (ni) 224 up(&ni->dev_lock); 225 } 226 227 static void refill_skbs(struct netpoll *np) 228 { 229 struct sk_buff_head *skb_pool; 230 struct sk_buff *skb; 231 232 skb_pool = &np->skb_pool; 233 234 while (READ_ONCE(skb_pool->qlen) < MAX_SKBS) { 235 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC); 236 if (!skb) 237 break; 238 239 skb_queue_tail(skb_pool, skb); 240 } 241 } 242 243 static void zap_completion_queue(void) 244 { 245 unsigned long flags; 246 struct softnet_data *sd = &get_cpu_var(softnet_data); 247 248 if (sd->completion_queue) { 249 struct sk_buff *clist; 250 251 local_irq_save(flags); 252 clist = sd->completion_queue; 253 sd->completion_queue = NULL; 254 local_irq_restore(flags); 255 256 while (clist != NULL) { 257 struct sk_buff *skb = clist; 258 clist = clist->next; 259 if (!skb_irq_freeable(skb)) { 260 refcount_set(&skb->users, 1); 261 dev_kfree_skb_any(skb); /* put this one back */ 262 } else { 263 __kfree_skb(skb); 264 } 265 } 266 } 267 268 put_cpu_var(softnet_data); 269 } 270 271 static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve) 272 { 273 int count = 0; 274 struct sk_buff *skb; 275 276 zap_completion_queue(); 277 repeat: 278 279 skb = alloc_skb(len, GFP_ATOMIC); 280 if (!skb) { 281 skb = skb_dequeue(&np->skb_pool); 282 schedule_work(&np->refill_wq); 283 } 284 285 if (!skb) { 286 if (++count < 10) { 287 netpoll_poll_dev(np->dev); 288 goto repeat; 289 } 290 return NULL; 291 } 292 293 refcount_set(&skb->users, 1); 294 skb_reserve(skb, reserve); 295 return skb; 296 } 297 298 static int netpoll_owner_active(struct net_device *dev) 299 { 300 struct napi_struct *napi; 301 302 list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) { 303 if (READ_ONCE(napi->poll_owner) == smp_processor_id()) 304 return 1; 305 } 306 return 0; 307 } 308 309 /* call with IRQ disabled */ 310 static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) 311 { 312 netdev_tx_t status = NETDEV_TX_BUSY; 313 netdev_tx_t ret = NET_XMIT_DROP; 314 struct net_device *dev; 315 unsigned long tries; 316 /* It is up to the caller to keep npinfo alive. */ 317 struct netpoll_info *npinfo; 318 319 lockdep_assert_irqs_disabled(); 320 321 dev = np->dev; 322 rcu_read_lock(); 323 npinfo = rcu_dereference_bh(dev->npinfo); 324 325 if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) { 326 dev_kfree_skb_irq(skb); 327 goto out; 328 } 329 330 /* don't get messages out of order, and no recursion */ 331 if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) { 332 struct netdev_queue *txq; 333 334 txq = netdev_core_pick_tx(dev, skb, NULL); 335 336 /* try until next clock tick */ 337 for (tries = jiffies_to_usecs(1)/USEC_PER_POLL; 338 tries > 0; --tries) { 339 if (HARD_TX_TRYLOCK(dev, txq)) { 340 if (!netif_xmit_stopped(txq)) 341 status = netpoll_start_xmit(skb, dev, txq); 342 343 HARD_TX_UNLOCK(dev, txq); 344 345 if (dev_xmit_complete(status)) 346 break; 347 348 } 349 350 /* tickle device maybe there is some cleanup */ 351 netpoll_poll_dev(np->dev); 352 353 udelay(USEC_PER_POLL); 354 } 355 356 WARN_ONCE(!irqs_disabled(), 357 "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pS)\n", 358 dev->name, dev->netdev_ops->ndo_start_xmit); 359 360 } 361 362 if (!dev_xmit_complete(status)) { 363 skb_queue_tail(&npinfo->txq, skb); 364 schedule_delayed_work(&npinfo->tx_work,0); 365 } 366 ret = NETDEV_TX_OK; 367 out: 368 rcu_read_unlock(); 369 return ret; 370 } 371 372 static void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb, 373 int len) 374 { 375 struct udphdr *udph; 376 int udp_len; 377 378 udp_len = len + sizeof(struct udphdr); 379 udph = udp_hdr(skb); 380 381 /* check needs to be set, since it will be consumed in csum_partial */ 382 udph->check = 0; 383 if (np->ipv6) 384 udph->check = csum_ipv6_magic(&np->local_ip.in6, 385 &np->remote_ip.in6, 386 udp_len, IPPROTO_UDP, 387 csum_partial(udph, udp_len, 0)); 388 else 389 udph->check = csum_tcpudp_magic(np->local_ip.ip, 390 np->remote_ip.ip, 391 udp_len, IPPROTO_UDP, 392 csum_partial(udph, udp_len, 0)); 393 if (udph->check == 0) 394 udph->check = CSUM_MANGLED_0; 395 } 396 397 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) 398 { 399 unsigned long flags; 400 netdev_tx_t ret; 401 402 if (unlikely(!np)) { 403 dev_kfree_skb_irq(skb); 404 ret = NET_XMIT_DROP; 405 } else { 406 local_irq_save(flags); 407 ret = __netpoll_send_skb(np, skb); 408 local_irq_restore(flags); 409 } 410 return ret; 411 } 412 EXPORT_SYMBOL(netpoll_send_skb); 413 414 static void push_ipv6(struct netpoll *np, struct sk_buff *skb, int len) 415 { 416 struct ipv6hdr *ip6h; 417 418 skb_push(skb, sizeof(struct ipv6hdr)); 419 skb_reset_network_header(skb); 420 ip6h = ipv6_hdr(skb); 421 422 /* ip6h->version = 6; ip6h->priority = 0; */ 423 *(unsigned char *)ip6h = 0x60; 424 ip6h->flow_lbl[0] = 0; 425 ip6h->flow_lbl[1] = 0; 426 ip6h->flow_lbl[2] = 0; 427 428 ip6h->payload_len = htons(sizeof(struct udphdr) + len); 429 ip6h->nexthdr = IPPROTO_UDP; 430 ip6h->hop_limit = 32; 431 ip6h->saddr = np->local_ip.in6; 432 ip6h->daddr = np->remote_ip.in6; 433 434 skb->protocol = htons(ETH_P_IPV6); 435 } 436 437 static void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len) 438 { 439 static atomic_t ip_ident; 440 struct iphdr *iph; 441 int ip_len; 442 443 ip_len = len + sizeof(struct udphdr) + sizeof(struct iphdr); 444 445 skb_push(skb, sizeof(struct iphdr)); 446 skb_reset_network_header(skb); 447 iph = ip_hdr(skb); 448 449 /* iph->version = 4; iph->ihl = 5; */ 450 *(unsigned char *)iph = 0x45; 451 iph->tos = 0; 452 put_unaligned(htons(ip_len), &iph->tot_len); 453 iph->id = htons(atomic_inc_return(&ip_ident)); 454 iph->frag_off = 0; 455 iph->ttl = 64; 456 iph->protocol = IPPROTO_UDP; 457 iph->check = 0; 458 put_unaligned(np->local_ip.ip, &iph->saddr); 459 put_unaligned(np->remote_ip.ip, &iph->daddr); 460 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); 461 skb->protocol = htons(ETH_P_IP); 462 } 463 464 static void push_udp(struct netpoll *np, struct sk_buff *skb, int len) 465 { 466 struct udphdr *udph; 467 int udp_len; 468 469 udp_len = len + sizeof(struct udphdr); 470 471 skb_push(skb, sizeof(struct udphdr)); 472 skb_reset_transport_header(skb); 473 474 udph = udp_hdr(skb); 475 udph->source = htons(np->local_port); 476 udph->dest = htons(np->remote_port); 477 udph->len = htons(udp_len); 478 479 netpoll_udp_checksum(np, skb, len); 480 } 481 482 static void push_eth(struct netpoll *np, struct sk_buff *skb) 483 { 484 struct ethhdr *eth; 485 486 eth = skb_push(skb, ETH_HLEN); 487 skb_reset_mac_header(skb); 488 ether_addr_copy(eth->h_source, np->dev->dev_addr); 489 ether_addr_copy(eth->h_dest, np->remote_mac); 490 if (np->ipv6) 491 eth->h_proto = htons(ETH_P_IPV6); 492 else 493 eth->h_proto = htons(ETH_P_IP); 494 } 495 496 int netpoll_send_udp(struct netpoll *np, const char *msg, int len) 497 { 498 int total_len, ip_len, udp_len; 499 struct sk_buff *skb; 500 501 if (!IS_ENABLED(CONFIG_PREEMPT_RT)) 502 WARN_ON_ONCE(!irqs_disabled()); 503 504 udp_len = len + sizeof(struct udphdr); 505 if (np->ipv6) 506 ip_len = udp_len + sizeof(struct ipv6hdr); 507 else 508 ip_len = udp_len + sizeof(struct iphdr); 509 510 total_len = ip_len + LL_RESERVED_SPACE(np->dev); 511 512 skb = find_skb(np, total_len + np->dev->needed_tailroom, 513 total_len - len); 514 if (!skb) 515 return -ENOMEM; 516 517 skb_copy_to_linear_data(skb, msg, len); 518 skb_put(skb, len); 519 520 push_udp(np, skb, len); 521 if (np->ipv6) 522 push_ipv6(np, skb, len); 523 else 524 push_ipv4(np, skb, len); 525 push_eth(np, skb); 526 skb->dev = np->dev; 527 528 return (int)netpoll_send_skb(np, skb); 529 } 530 EXPORT_SYMBOL(netpoll_send_udp); 531 532 533 static void skb_pool_flush(struct netpoll *np) 534 { 535 struct sk_buff_head *skb_pool; 536 537 cancel_work_sync(&np->refill_wq); 538 skb_pool = &np->skb_pool; 539 skb_queue_purge_reason(skb_pool, SKB_CONSUMED); 540 } 541 542 static void refill_skbs_work_handler(struct work_struct *work) 543 { 544 struct netpoll *np = 545 container_of(work, struct netpoll, refill_wq); 546 547 refill_skbs(np); 548 } 549 550 int __netpoll_setup(struct netpoll *np, struct net_device *ndev) 551 { 552 struct netpoll_info *npinfo; 553 const struct net_device_ops *ops; 554 int err; 555 556 skb_queue_head_init(&np->skb_pool); 557 558 if (ndev->priv_flags & IFF_DISABLE_NETPOLL) { 559 np_err(np, "%s doesn't support polling, aborting\n", 560 ndev->name); 561 err = -ENOTSUPP; 562 goto out; 563 } 564 565 npinfo = rtnl_dereference(ndev->npinfo); 566 if (!npinfo) { 567 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL); 568 if (!npinfo) { 569 err = -ENOMEM; 570 goto out; 571 } 572 573 sema_init(&npinfo->dev_lock, 1); 574 skb_queue_head_init(&npinfo->txq); 575 INIT_DELAYED_WORK(&npinfo->tx_work, queue_process); 576 577 refcount_set(&npinfo->refcnt, 1); 578 579 ops = ndev->netdev_ops; 580 if (ops->ndo_netpoll_setup) { 581 err = ops->ndo_netpoll_setup(ndev); 582 if (err) 583 goto free_npinfo; 584 } 585 } else { 586 refcount_inc(&npinfo->refcnt); 587 } 588 589 np->dev = ndev; 590 strscpy(np->dev_name, ndev->name, IFNAMSIZ); 591 592 /* fill up the skb queue */ 593 refill_skbs(np); 594 INIT_WORK(&np->refill_wq, refill_skbs_work_handler); 595 596 /* last thing to do is link it to the net device structure */ 597 rcu_assign_pointer(ndev->npinfo, npinfo); 598 599 return 0; 600 601 free_npinfo: 602 kfree(npinfo); 603 out: 604 return err; 605 } 606 EXPORT_SYMBOL_GPL(__netpoll_setup); 607 608 /* 609 * Returns a pointer to a string representation of the identifier used 610 * to select the egress interface for the given netpoll instance. buf 611 * must be a buffer of length at least MAC_ADDR_STR_LEN + 1. 612 */ 613 static char *egress_dev(struct netpoll *np, char *buf) 614 { 615 if (np->dev_name[0]) 616 return np->dev_name; 617 618 snprintf(buf, MAC_ADDR_STR_LEN, "%pM", np->dev_mac); 619 return buf; 620 } 621 622 static void netpoll_wait_carrier(struct netpoll *np, struct net_device *ndev, 623 unsigned int timeout) 624 { 625 unsigned long atmost; 626 627 atmost = jiffies + timeout * HZ; 628 while (!netif_carrier_ok(ndev)) { 629 if (time_after(jiffies, atmost)) { 630 np_notice(np, "timeout waiting for carrier\n"); 631 break; 632 } 633 msleep(1); 634 } 635 } 636 637 /* 638 * Take the IPv6 from ndev and populate local_ip structure in netpoll 639 */ 640 static int netpoll_take_ipv6(struct netpoll *np, struct net_device *ndev) 641 { 642 char buf[MAC_ADDR_STR_LEN + 1]; 643 int err = -EDESTADDRREQ; 644 struct inet6_dev *idev; 645 646 if (!IS_ENABLED(CONFIG_IPV6)) { 647 np_err(np, "IPv6 is not supported %s, aborting\n", 648 egress_dev(np, buf)); 649 return -EINVAL; 650 } 651 652 idev = __in6_dev_get(ndev); 653 if (idev) { 654 struct inet6_ifaddr *ifp; 655 656 read_lock_bh(&idev->lock); 657 list_for_each_entry(ifp, &idev->addr_list, if_list) { 658 if (!!(ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL) != 659 !!(ipv6_addr_type(&np->remote_ip.in6) & IPV6_ADDR_LINKLOCAL)) 660 continue; 661 /* Got the IP, let's return */ 662 np->local_ip.in6 = ifp->addr; 663 err = 0; 664 break; 665 } 666 read_unlock_bh(&idev->lock); 667 } 668 if (err) { 669 np_err(np, "no IPv6 address for %s, aborting\n", 670 egress_dev(np, buf)); 671 return err; 672 } 673 674 np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6); 675 return 0; 676 } 677 678 /* 679 * Take the IPv4 from ndev and populate local_ip structure in netpoll 680 */ 681 static int netpoll_take_ipv4(struct netpoll *np, struct net_device *ndev) 682 { 683 char buf[MAC_ADDR_STR_LEN + 1]; 684 const struct in_ifaddr *ifa; 685 struct in_device *in_dev; 686 687 in_dev = __in_dev_get_rtnl(ndev); 688 if (!in_dev) { 689 np_err(np, "no IP address for %s, aborting\n", 690 egress_dev(np, buf)); 691 return -EDESTADDRREQ; 692 } 693 694 ifa = rtnl_dereference(in_dev->ifa_list); 695 if (!ifa) { 696 np_err(np, "no IP address for %s, aborting\n", 697 egress_dev(np, buf)); 698 return -EDESTADDRREQ; 699 } 700 701 np->local_ip.ip = ifa->ifa_local; 702 np_info(np, "local IP %pI4\n", &np->local_ip.ip); 703 704 return 0; 705 } 706 707 int netpoll_setup(struct netpoll *np) 708 { 709 struct net *net = current->nsproxy->net_ns; 710 char buf[MAC_ADDR_STR_LEN + 1]; 711 struct net_device *ndev = NULL; 712 bool ip_overwritten = false; 713 int err; 714 715 rtnl_lock(); 716 if (np->dev_name[0]) 717 ndev = __dev_get_by_name(net, np->dev_name); 718 else if (is_valid_ether_addr(np->dev_mac)) 719 ndev = dev_getbyhwaddr(net, ARPHRD_ETHER, np->dev_mac); 720 721 if (!ndev) { 722 np_err(np, "%s doesn't exist, aborting\n", egress_dev(np, buf)); 723 err = -ENODEV; 724 goto unlock; 725 } 726 netdev_hold(ndev, &np->dev_tracker, GFP_KERNEL); 727 728 if (netdev_master_upper_dev_get(ndev)) { 729 np_err(np, "%s is a slave device, aborting\n", 730 egress_dev(np, buf)); 731 err = -EBUSY; 732 goto put; 733 } 734 735 if (!netif_running(ndev)) { 736 np_info(np, "device %s not up yet, forcing it\n", 737 egress_dev(np, buf)); 738 739 err = dev_open(ndev, NULL); 740 if (err) { 741 np_err(np, "failed to open %s\n", ndev->name); 742 goto put; 743 } 744 745 rtnl_unlock(); 746 netpoll_wait_carrier(np, ndev, carrier_timeout); 747 rtnl_lock(); 748 } 749 750 if (!np->local_ip.ip) { 751 if (!np->ipv6) { 752 err = netpoll_take_ipv4(np, ndev); 753 if (err) 754 goto put; 755 } else { 756 err = netpoll_take_ipv6(np, ndev); 757 if (err) 758 goto put; 759 } 760 ip_overwritten = true; 761 } 762 763 err = __netpoll_setup(np, ndev); 764 if (err) 765 goto flush; 766 rtnl_unlock(); 767 768 /* Make sure all NAPI polls which started before dev->npinfo 769 * was visible have exited before we start calling NAPI poll. 770 * NAPI skips locking if dev->npinfo is NULL. 771 */ 772 synchronize_rcu(); 773 774 return 0; 775 776 flush: 777 skb_pool_flush(np); 778 put: 779 DEBUG_NET_WARN_ON_ONCE(np->dev); 780 if (ip_overwritten) 781 memset(&np->local_ip, 0, sizeof(np->local_ip)); 782 netdev_put(ndev, &np->dev_tracker); 783 unlock: 784 rtnl_unlock(); 785 return err; 786 } 787 EXPORT_SYMBOL(netpoll_setup); 788 789 static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head) 790 { 791 struct netpoll_info *npinfo = 792 container_of(rcu_head, struct netpoll_info, rcu); 793 794 skb_queue_purge(&npinfo->txq); 795 796 /* we can't call cancel_delayed_work_sync here, as we are in softirq */ 797 cancel_delayed_work(&npinfo->tx_work); 798 799 /* clean after last, unfinished work */ 800 __skb_queue_purge(&npinfo->txq); 801 /* now cancel it again */ 802 cancel_delayed_work(&npinfo->tx_work); 803 kfree(npinfo); 804 } 805 806 static void __netpoll_cleanup(struct netpoll *np) 807 { 808 struct netpoll_info *npinfo; 809 810 npinfo = rtnl_dereference(np->dev->npinfo); 811 if (!npinfo) 812 return; 813 814 if (refcount_dec_and_test(&npinfo->refcnt)) { 815 const struct net_device_ops *ops; 816 817 ops = np->dev->netdev_ops; 818 if (ops->ndo_netpoll_cleanup) 819 ops->ndo_netpoll_cleanup(np->dev); 820 821 RCU_INIT_POINTER(np->dev->npinfo, NULL); 822 call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info); 823 } else 824 RCU_INIT_POINTER(np->dev->npinfo, NULL); 825 826 skb_pool_flush(np); 827 } 828 829 void __netpoll_free(struct netpoll *np) 830 { 831 ASSERT_RTNL(); 832 833 /* Wait for transmitting packets to finish before freeing. */ 834 synchronize_net(); 835 __netpoll_cleanup(np); 836 kfree(np); 837 } 838 EXPORT_SYMBOL_GPL(__netpoll_free); 839 840 void do_netpoll_cleanup(struct netpoll *np) 841 { 842 __netpoll_cleanup(np); 843 netdev_put(np->dev, &np->dev_tracker); 844 np->dev = NULL; 845 } 846 EXPORT_SYMBOL(do_netpoll_cleanup); 847 848 void netpoll_cleanup(struct netpoll *np) 849 { 850 rtnl_lock(); 851 if (!np->dev) 852 goto out; 853 do_netpoll_cleanup(np); 854 out: 855 rtnl_unlock(); 856 } 857 EXPORT_SYMBOL(netpoll_cleanup); 858