netpoll.c revision 068c6e98bc7ec4419299b38cd40be26ebf4bdeda
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/if_arp.h> 17#include <linux/inetdevice.h> 18#include <linux/inet.h> 19#include <linux/interrupt.h> 20#include <linux/netpoll.h> 21#include <linux/sched.h> 22#include <linux/delay.h> 23#include <linux/rcupdate.h> 24#include <linux/workqueue.h> 25#include <net/tcp.h> 26#include <net/udp.h> 27#include <asm/unaligned.h> 28 29/* 30 * We maintain a small pool of fully-sized skbs, to make sure the 31 * message gets out even in extreme OOM situations. 32 */ 33 34#define MAX_UDP_CHUNK 1460 35#define MAX_SKBS 32 36#define MAX_QUEUE_DEPTH (MAX_SKBS / 2) 37#define MAX_RETRIES 20000 38 39static DEFINE_SPINLOCK(skb_list_lock); 40static int nr_skbs; 41static struct sk_buff *skbs; 42 43static DEFINE_SPINLOCK(queue_lock); 44static int queue_depth; 45static struct sk_buff *queue_head, *queue_tail; 46 47static atomic_t trapped; 48 49#define NETPOLL_RX_ENABLED 1 50#define NETPOLL_RX_DROP 2 51 52#define MAX_SKB_SIZE \ 53 (MAX_UDP_CHUNK + sizeof(struct udphdr) + \ 54 sizeof(struct iphdr) + sizeof(struct ethhdr)) 55 56static void zap_completion_queue(void); 57static void arp_reply(struct sk_buff *skb); 58 59static void queue_process(void *p) 60{ 61 unsigned long flags; 62 struct sk_buff *skb; 63 64 while (queue_head) { 65 spin_lock_irqsave(&queue_lock, flags); 66 67 skb = queue_head; 68 queue_head = skb->next; 69 if (skb == queue_tail) 70 queue_head = NULL; 71 72 queue_depth--; 73 74 spin_unlock_irqrestore(&queue_lock, flags); 75 76 dev_queue_xmit(skb); 77 } 78} 79 80static DECLARE_WORK(send_queue, queue_process, NULL); 81 82void netpoll_queue(struct sk_buff *skb) 83{ 84 unsigned long flags; 85 86 if (queue_depth == MAX_QUEUE_DEPTH) { 87 __kfree_skb(skb); 88 return; 89 } 90 91 spin_lock_irqsave(&queue_lock, flags); 92 if (!queue_head) 93 queue_head = skb; 94 else 95 queue_tail->next = skb; 96 queue_tail = skb; 97 queue_depth++; 98 spin_unlock_irqrestore(&queue_lock, flags); 99 100 schedule_work(&send_queue); 101} 102 103static int checksum_udp(struct sk_buff *skb, struct udphdr *uh, 104 unsigned short ulen, u32 saddr, u32 daddr) 105{ 106 unsigned int psum; 107 108 if (uh->check == 0 || skb->ip_summed == CHECKSUM_UNNECESSARY) 109 return 0; 110 111 psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0); 112 113 if (skb->ip_summed == CHECKSUM_HW && 114 !(u16)csum_fold(csum_add(psum, skb->csum))) 115 return 0; 116 117 skb->csum = psum; 118 119 return __skb_checksum_complete(skb); 120} 121 122/* 123 * Check whether delayed processing was scheduled for our NIC. If so, 124 * we attempt to grab the poll lock and use ->poll() to pump the card. 125 * If this fails, either we've recursed in ->poll() or it's already 126 * running on another CPU. 127 * 128 * Note: we don't mask interrupts with this lock because we're using 129 * trylock here and interrupts are already disabled in the softirq 130 * case. Further, we test the poll_owner to avoid recursion on UP 131 * systems where the lock doesn't exist. 132 * 133 * In cases where there is bi-directional communications, reading only 134 * one message at a time can lead to packets being dropped by the 135 * network adapter, forcing superfluous retries and possibly timeouts. 136 * Thus, we set our budget to greater than 1. 137 */ 138static void poll_napi(struct netpoll *np) 139{ 140 struct netpoll_info *npinfo = np->dev->npinfo; 141 int budget = 16; 142 143 if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) && 144 npinfo->poll_owner != smp_processor_id() && 145 spin_trylock(&npinfo->poll_lock)) { 146 npinfo->rx_flags |= NETPOLL_RX_DROP; 147 atomic_inc(&trapped); 148 149 np->dev->poll(np->dev, &budget); 150 151 atomic_dec(&trapped); 152 npinfo->rx_flags &= ~NETPOLL_RX_DROP; 153 spin_unlock(&npinfo->poll_lock); 154 } 155} 156 157static void service_arp_queue(struct netpoll_info *npi) 158{ 159 struct sk_buff *skb; 160 161 if (unlikely(!npi)) 162 return; 163 164 skb = skb_dequeue(&npi->arp_tx); 165 166 while (skb != NULL) { 167 arp_reply(skb); 168 skb = skb_dequeue(&npi->arp_tx); 169 } 170 return; 171} 172 173void netpoll_poll(struct netpoll *np) 174{ 175 if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller) 176 return; 177 178 /* Process pending work on NIC */ 179 np->dev->poll_controller(np->dev); 180 if (np->dev->poll) 181 poll_napi(np); 182 183 service_arp_queue(np->dev->npinfo); 184 185 zap_completion_queue(); 186} 187 188static void refill_skbs(void) 189{ 190 struct sk_buff *skb; 191 unsigned long flags; 192 193 spin_lock_irqsave(&skb_list_lock, flags); 194 while (nr_skbs < MAX_SKBS) { 195 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC); 196 if (!skb) 197 break; 198 199 skb->next = skbs; 200 skbs = skb; 201 nr_skbs++; 202 } 203 spin_unlock_irqrestore(&skb_list_lock, flags); 204} 205 206static void zap_completion_queue(void) 207{ 208 unsigned long flags; 209 struct softnet_data *sd = &get_cpu_var(softnet_data); 210 211 if (sd->completion_queue) { 212 struct sk_buff *clist; 213 214 local_irq_save(flags); 215 clist = sd->completion_queue; 216 sd->completion_queue = NULL; 217 local_irq_restore(flags); 218 219 while (clist != NULL) { 220 struct sk_buff *skb = clist; 221 clist = clist->next; 222 if(skb->destructor) 223 dev_kfree_skb_any(skb); /* put this one back */ 224 else 225 __kfree_skb(skb); 226 } 227 } 228 229 put_cpu_var(softnet_data); 230} 231 232static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve) 233{ 234 int once = 1, count = 0; 235 unsigned long flags; 236 struct sk_buff *skb = NULL; 237 238 zap_completion_queue(); 239repeat: 240 if (nr_skbs < MAX_SKBS) 241 refill_skbs(); 242 243 skb = alloc_skb(len, GFP_ATOMIC); 244 245 if (!skb) { 246 spin_lock_irqsave(&skb_list_lock, flags); 247 skb = skbs; 248 if (skb) { 249 skbs = skb->next; 250 skb->next = NULL; 251 nr_skbs--; 252 } 253 spin_unlock_irqrestore(&skb_list_lock, flags); 254 } 255 256 if(!skb) { 257 count++; 258 if (once && (count == 1000000)) { 259 printk("out of netpoll skbs!\n"); 260 once = 0; 261 } 262 netpoll_poll(np); 263 goto repeat; 264 } 265 266 atomic_set(&skb->users, 1); 267 skb_reserve(skb, reserve); 268 return skb; 269} 270 271static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) 272{ 273 int status; 274 struct netpoll_info *npinfo; 275 276 if (!np || !np->dev || !netif_running(np->dev)) { 277 __kfree_skb(skb); 278 return; 279 } 280 281 npinfo = np->dev->npinfo; 282 283 /* avoid recursion */ 284 if (npinfo->poll_owner == smp_processor_id() || 285 np->dev->xmit_lock_owner == smp_processor_id()) { 286 if (np->drop) 287 np->drop(skb); 288 else 289 __kfree_skb(skb); 290 return; 291 } 292 293 do { 294 npinfo->tries--; 295 netif_tx_lock(np->dev); 296 297 /* 298 * network drivers do not expect to be called if the queue is 299 * stopped. 300 */ 301 status = NETDEV_TX_BUSY; 302 if (!netif_queue_stopped(np->dev)) 303 status = np->dev->hard_start_xmit(skb, np->dev); 304 305 netif_tx_unlock(np->dev); 306 307 /* success */ 308 if(!status) { 309 npinfo->tries = MAX_RETRIES; /* reset */ 310 return; 311 } 312 313 /* transmit busy */ 314 netpoll_poll(np); 315 udelay(50); 316 } while (npinfo->tries > 0); 317} 318 319void netpoll_send_udp(struct netpoll *np, const char *msg, int len) 320{ 321 int total_len, eth_len, ip_len, udp_len; 322 struct sk_buff *skb; 323 struct udphdr *udph; 324 struct iphdr *iph; 325 struct ethhdr *eth; 326 327 udp_len = len + sizeof(*udph); 328 ip_len = eth_len = udp_len + sizeof(*iph); 329 total_len = eth_len + ETH_HLEN + NET_IP_ALIGN; 330 331 skb = find_skb(np, total_len, total_len - len); 332 if (!skb) 333 return; 334 335 memcpy(skb->data, msg, len); 336 skb->len += len; 337 338 udph = (struct udphdr *) skb_push(skb, sizeof(*udph)); 339 udph->source = htons(np->local_port); 340 udph->dest = htons(np->remote_port); 341 udph->len = htons(udp_len); 342 udph->check = 0; 343 344 iph = (struct iphdr *)skb_push(skb, sizeof(*iph)); 345 346 /* iph->version = 4; iph->ihl = 5; */ 347 put_unaligned(0x45, (unsigned char *)iph); 348 iph->tos = 0; 349 put_unaligned(htons(ip_len), &(iph->tot_len)); 350 iph->id = 0; 351 iph->frag_off = 0; 352 iph->ttl = 64; 353 iph->protocol = IPPROTO_UDP; 354 iph->check = 0; 355 put_unaligned(htonl(np->local_ip), &(iph->saddr)); 356 put_unaligned(htonl(np->remote_ip), &(iph->daddr)); 357 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); 358 359 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN); 360 361 eth->h_proto = htons(ETH_P_IP); 362 memcpy(eth->h_source, np->local_mac, 6); 363 memcpy(eth->h_dest, np->remote_mac, 6); 364 365 skb->dev = np->dev; 366 367 netpoll_send_skb(np, skb); 368} 369 370static void arp_reply(struct sk_buff *skb) 371{ 372 struct netpoll_info *npinfo = skb->dev->npinfo; 373 struct arphdr *arp; 374 unsigned char *arp_ptr; 375 int size, type = ARPOP_REPLY, ptype = ETH_P_ARP; 376 u32 sip, tip; 377 struct sk_buff *send_skb; 378 struct netpoll *np = NULL; 379 380 if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev) 381 np = npinfo->rx_np; 382 if (!np) 383 return; 384 385 /* No arp on this interface */ 386 if (skb->dev->flags & IFF_NOARP) 387 return; 388 389 if (!pskb_may_pull(skb, (sizeof(struct arphdr) + 390 (2 * skb->dev->addr_len) + 391 (2 * sizeof(u32))))) 392 return; 393 394 skb->h.raw = skb->nh.raw = skb->data; 395 arp = skb->nh.arph; 396 397 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 398 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 399 arp->ar_pro != htons(ETH_P_IP) || 400 arp->ar_op != htons(ARPOP_REQUEST)) 401 return; 402 403 arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len; 404 memcpy(&sip, arp_ptr, 4); 405 arp_ptr += 4 + skb->dev->addr_len; 406 memcpy(&tip, arp_ptr, 4); 407 408 /* Should we ignore arp? */ 409 if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip)) 410 return; 411 412 size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4); 413 send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev), 414 LL_RESERVED_SPACE(np->dev)); 415 416 if (!send_skb) 417 return; 418 419 send_skb->nh.raw = send_skb->data; 420 arp = (struct arphdr *) skb_put(send_skb, size); 421 send_skb->dev = skb->dev; 422 send_skb->protocol = htons(ETH_P_ARP); 423 424 /* Fill the device header for the ARP frame */ 425 426 if (np->dev->hard_header && 427 np->dev->hard_header(send_skb, skb->dev, ptype, 428 np->remote_mac, np->local_mac, 429 send_skb->len) < 0) { 430 kfree_skb(send_skb); 431 return; 432 } 433 434 /* 435 * Fill out the arp protocol part. 436 * 437 * we only support ethernet device type, 438 * which (according to RFC 1390) should always equal 1 (Ethernet). 439 */ 440 441 arp->ar_hrd = htons(np->dev->type); 442 arp->ar_pro = htons(ETH_P_IP); 443 arp->ar_hln = np->dev->addr_len; 444 arp->ar_pln = 4; 445 arp->ar_op = htons(type); 446 447 arp_ptr=(unsigned char *)(arp + 1); 448 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len); 449 arp_ptr += np->dev->addr_len; 450 memcpy(arp_ptr, &tip, 4); 451 arp_ptr += 4; 452 memcpy(arp_ptr, np->remote_mac, np->dev->addr_len); 453 arp_ptr += np->dev->addr_len; 454 memcpy(arp_ptr, &sip, 4); 455 456 netpoll_send_skb(np, send_skb); 457} 458 459int __netpoll_rx(struct sk_buff *skb) 460{ 461 int proto, len, ulen; 462 struct iphdr *iph; 463 struct udphdr *uh; 464 struct netpoll_info *npi = skb->dev->npinfo; 465 struct netpoll *np = npi->rx_np; 466 467 468 if (!np) 469 goto out; 470 if (skb->dev->type != ARPHRD_ETHER) 471 goto out; 472 473 /* check if netpoll clients need ARP */ 474 if (skb->protocol == __constant_htons(ETH_P_ARP) && 475 atomic_read(&trapped)) { 476 skb_queue_tail(&npi->arp_tx, skb); 477 return 1; 478 } 479 480 proto = ntohs(eth_hdr(skb)->h_proto); 481 if (proto != ETH_P_IP) 482 goto out; 483 if (skb->pkt_type == PACKET_OTHERHOST) 484 goto out; 485 if (skb_shared(skb)) 486 goto out; 487 488 iph = (struct iphdr *)skb->data; 489 if (!pskb_may_pull(skb, sizeof(struct iphdr))) 490 goto out; 491 if (iph->ihl < 5 || iph->version != 4) 492 goto out; 493 if (!pskb_may_pull(skb, iph->ihl*4)) 494 goto out; 495 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0) 496 goto out; 497 498 len = ntohs(iph->tot_len); 499 if (skb->len < len || len < iph->ihl*4) 500 goto out; 501 502 if (iph->protocol != IPPROTO_UDP) 503 goto out; 504 505 len -= iph->ihl*4; 506 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4); 507 ulen = ntohs(uh->len); 508 509 if (ulen != len) 510 goto out; 511 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr)) 512 goto out; 513 if (np->local_ip && np->local_ip != ntohl(iph->daddr)) 514 goto out; 515 if (np->remote_ip && np->remote_ip != ntohl(iph->saddr)) 516 goto out; 517 if (np->local_port && np->local_port != ntohs(uh->dest)) 518 goto out; 519 520 np->rx_hook(np, ntohs(uh->source), 521 (char *)(uh+1), 522 ulen - sizeof(struct udphdr)); 523 524 kfree_skb(skb); 525 return 1; 526 527out: 528 if (atomic_read(&trapped)) { 529 kfree_skb(skb); 530 return 1; 531 } 532 533 return 0; 534} 535 536int netpoll_parse_options(struct netpoll *np, char *opt) 537{ 538 char *cur=opt, *delim; 539 540 if(*cur != '@') { 541 if ((delim = strchr(cur, '@')) == NULL) 542 goto parse_failed; 543 *delim=0; 544 np->local_port=simple_strtol(cur, NULL, 10); 545 cur=delim; 546 } 547 cur++; 548 printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port); 549 550 if(*cur != '/') { 551 if ((delim = strchr(cur, '/')) == NULL) 552 goto parse_failed; 553 *delim=0; 554 np->local_ip=ntohl(in_aton(cur)); 555 cur=delim; 556 557 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n", 558 np->name, HIPQUAD(np->local_ip)); 559 } 560 cur++; 561 562 if ( *cur != ',') { 563 /* parse out dev name */ 564 if ((delim = strchr(cur, ',')) == NULL) 565 goto parse_failed; 566 *delim=0; 567 strlcpy(np->dev_name, cur, sizeof(np->dev_name)); 568 cur=delim; 569 } 570 cur++; 571 572 printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name); 573 574 if ( *cur != '@' ) { 575 /* dst port */ 576 if ((delim = strchr(cur, '@')) == NULL) 577 goto parse_failed; 578 *delim=0; 579 np->remote_port=simple_strtol(cur, NULL, 10); 580 cur=delim; 581 } 582 cur++; 583 printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port); 584 585 /* dst ip */ 586 if ((delim = strchr(cur, '/')) == NULL) 587 goto parse_failed; 588 *delim=0; 589 np->remote_ip=ntohl(in_aton(cur)); 590 cur=delim+1; 591 592 printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n", 593 np->name, HIPQUAD(np->remote_ip)); 594 595 if( *cur != 0 ) 596 { 597 /* MAC address */ 598 if ((delim = strchr(cur, ':')) == NULL) 599 goto parse_failed; 600 *delim=0; 601 np->remote_mac[0]=simple_strtol(cur, NULL, 16); 602 cur=delim+1; 603 if ((delim = strchr(cur, ':')) == NULL) 604 goto parse_failed; 605 *delim=0; 606 np->remote_mac[1]=simple_strtol(cur, NULL, 16); 607 cur=delim+1; 608 if ((delim = strchr(cur, ':')) == NULL) 609 goto parse_failed; 610 *delim=0; 611 np->remote_mac[2]=simple_strtol(cur, NULL, 16); 612 cur=delim+1; 613 if ((delim = strchr(cur, ':')) == NULL) 614 goto parse_failed; 615 *delim=0; 616 np->remote_mac[3]=simple_strtol(cur, NULL, 16); 617 cur=delim+1; 618 if ((delim = strchr(cur, ':')) == NULL) 619 goto parse_failed; 620 *delim=0; 621 np->remote_mac[4]=simple_strtol(cur, NULL, 16); 622 cur=delim+1; 623 np->remote_mac[5]=simple_strtol(cur, NULL, 16); 624 } 625 626 printk(KERN_INFO "%s: remote ethernet address " 627 "%02x:%02x:%02x:%02x:%02x:%02x\n", 628 np->name, 629 np->remote_mac[0], 630 np->remote_mac[1], 631 np->remote_mac[2], 632 np->remote_mac[3], 633 np->remote_mac[4], 634 np->remote_mac[5]); 635 636 return 0; 637 638 parse_failed: 639 printk(KERN_INFO "%s: couldn't parse config at %s!\n", 640 np->name, cur); 641 return -1; 642} 643 644int netpoll_setup(struct netpoll *np) 645{ 646 struct net_device *ndev = NULL; 647 struct in_device *in_dev; 648 struct netpoll_info *npinfo; 649 unsigned long flags; 650 651 if (np->dev_name) 652 ndev = dev_get_by_name(np->dev_name); 653 if (!ndev) { 654 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n", 655 np->name, np->dev_name); 656 return -1; 657 } 658 659 np->dev = ndev; 660 if (!ndev->npinfo) { 661 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL); 662 if (!npinfo) 663 goto release; 664 665 npinfo->rx_flags = 0; 666 npinfo->rx_np = NULL; 667 spin_lock_init(&npinfo->poll_lock); 668 npinfo->poll_owner = -1; 669 npinfo->tries = MAX_RETRIES; 670 spin_lock_init(&npinfo->rx_lock); 671 skb_queue_head_init(&npinfo->arp_tx); 672 } else 673 npinfo = ndev->npinfo; 674 675 if (!ndev->poll_controller) { 676 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n", 677 np->name, np->dev_name); 678 goto release; 679 } 680 681 if (!netif_running(ndev)) { 682 unsigned long atmost, atleast; 683 684 printk(KERN_INFO "%s: device %s not up yet, forcing it\n", 685 np->name, np->dev_name); 686 687 rtnl_lock(); 688 if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) { 689 printk(KERN_ERR "%s: failed to open %s\n", 690 np->name, np->dev_name); 691 rtnl_unlock(); 692 goto release; 693 } 694 rtnl_unlock(); 695 696 atleast = jiffies + HZ/10; 697 atmost = jiffies + 4*HZ; 698 while (!netif_carrier_ok(ndev)) { 699 if (time_after(jiffies, atmost)) { 700 printk(KERN_NOTICE 701 "%s: timeout waiting for carrier\n", 702 np->name); 703 break; 704 } 705 cond_resched(); 706 } 707 708 /* If carrier appears to come up instantly, we don't 709 * trust it and pause so that we don't pump all our 710 * queued console messages into the bitbucket. 711 */ 712 713 if (time_before(jiffies, atleast)) { 714 printk(KERN_NOTICE "%s: carrier detect appears" 715 " untrustworthy, waiting 4 seconds\n", 716 np->name); 717 msleep(4000); 718 } 719 } 720 721 if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr) 722 memcpy(np->local_mac, ndev->dev_addr, 6); 723 724 if (!np->local_ip) { 725 rcu_read_lock(); 726 in_dev = __in_dev_get_rcu(ndev); 727 728 if (!in_dev || !in_dev->ifa_list) { 729 rcu_read_unlock(); 730 printk(KERN_ERR "%s: no IP address for %s, aborting\n", 731 np->name, np->dev_name); 732 goto release; 733 } 734 735 np->local_ip = ntohl(in_dev->ifa_list->ifa_local); 736 rcu_read_unlock(); 737 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n", 738 np->name, HIPQUAD(np->local_ip)); 739 } 740 741 if (np->rx_hook) { 742 spin_lock_irqsave(&npinfo->rx_lock, flags); 743 npinfo->rx_flags |= NETPOLL_RX_ENABLED; 744 npinfo->rx_np = np; 745 spin_unlock_irqrestore(&npinfo->rx_lock, flags); 746 } 747 748 /* fill up the skb queue */ 749 refill_skbs(); 750 751 /* last thing to do is link it to the net device structure */ 752 ndev->npinfo = npinfo; 753 754 /* avoid racing with NAPI reading npinfo */ 755 synchronize_rcu(); 756 757 return 0; 758 759 release: 760 if (!ndev->npinfo) 761 kfree(npinfo); 762 np->dev = NULL; 763 dev_put(ndev); 764 return -1; 765} 766 767void netpoll_cleanup(struct netpoll *np) 768{ 769 struct netpoll_info *npinfo; 770 unsigned long flags; 771 772 if (np->dev) { 773 npinfo = np->dev->npinfo; 774 if (npinfo && npinfo->rx_np == np) { 775 spin_lock_irqsave(&npinfo->rx_lock, flags); 776 npinfo->rx_np = NULL; 777 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED; 778 spin_unlock_irqrestore(&npinfo->rx_lock, flags); 779 } 780 dev_put(np->dev); 781 } 782 783 np->dev = NULL; 784} 785 786int netpoll_trap(void) 787{ 788 return atomic_read(&trapped); 789} 790 791void netpoll_set_trap(int trap) 792{ 793 if (trap) 794 atomic_inc(&trapped); 795 else 796 atomic_dec(&trapped); 797} 798 799EXPORT_SYMBOL(netpoll_set_trap); 800EXPORT_SYMBOL(netpoll_trap); 801EXPORT_SYMBOL(netpoll_parse_options); 802EXPORT_SYMBOL(netpoll_setup); 803EXPORT_SYMBOL(netpoll_cleanup); 804EXPORT_SYMBOL(netpoll_send_udp); 805EXPORT_SYMBOL(netpoll_poll); 806EXPORT_SYMBOL(netpoll_queue); 807