netpoll.c revision 6756ae4b4e97aba48c042b4aa6b77a18f507d2cb
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); 57 58static void queue_process(void *p) 59{ 60 unsigned long flags; 61 struct sk_buff *skb; 62 63 while (queue_head) { 64 spin_lock_irqsave(&queue_lock, flags); 65 66 skb = queue_head; 67 queue_head = skb->next; 68 if (skb == queue_tail) 69 queue_head = NULL; 70 71 queue_depth--; 72 73 spin_unlock_irqrestore(&queue_lock, flags); 74 75 dev_queue_xmit(skb); 76 } 77} 78 79static DECLARE_WORK(send_queue, queue_process, NULL); 80 81void netpoll_queue(struct sk_buff *skb) 82{ 83 unsigned long flags; 84 85 if (queue_depth == MAX_QUEUE_DEPTH) { 86 __kfree_skb(skb); 87 return; 88 } 89 90 spin_lock_irqsave(&queue_lock, flags); 91 if (!queue_head) 92 queue_head = skb; 93 else 94 queue_tail->next = skb; 95 queue_tail = skb; 96 queue_depth++; 97 spin_unlock_irqrestore(&queue_lock, flags); 98 99 schedule_work(&send_queue); 100} 101 102static int checksum_udp(struct sk_buff *skb, struct udphdr *uh, 103 unsigned short ulen, u32 saddr, u32 daddr) 104{ 105 unsigned int psum; 106 107 if (uh->check == 0 || skb->ip_summed == CHECKSUM_UNNECESSARY) 108 return 0; 109 110 psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0); 111 112 if (skb->ip_summed == CHECKSUM_HW && 113 !(u16)csum_fold(csum_add(psum, skb->csum))) 114 return 0; 115 116 skb->csum = psum; 117 118 return __skb_checksum_complete(skb); 119} 120 121/* 122 * Check whether delayed processing was scheduled for our NIC. If so, 123 * we attempt to grab the poll lock and use ->poll() to pump the card. 124 * If this fails, either we've recursed in ->poll() or it's already 125 * running on another CPU. 126 * 127 * Note: we don't mask interrupts with this lock because we're using 128 * trylock here and interrupts are already disabled in the softirq 129 * case. Further, we test the poll_owner to avoid recursion on UP 130 * systems where the lock doesn't exist. 131 * 132 * In cases where there is bi-directional communications, reading only 133 * one message at a time can lead to packets being dropped by the 134 * network adapter, forcing superfluous retries and possibly timeouts. 135 * Thus, we set our budget to greater than 1. 136 */ 137static void poll_napi(struct netpoll *np) 138{ 139 struct netpoll_info *npinfo = np->dev->npinfo; 140 int budget = 16; 141 142 if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) && 143 npinfo->poll_owner != smp_processor_id() && 144 spin_trylock(&npinfo->poll_lock)) { 145 npinfo->rx_flags |= NETPOLL_RX_DROP; 146 atomic_inc(&trapped); 147 148 np->dev->poll(np->dev, &budget); 149 150 atomic_dec(&trapped); 151 npinfo->rx_flags &= ~NETPOLL_RX_DROP; 152 spin_unlock(&npinfo->poll_lock); 153 } 154} 155 156void netpoll_poll(struct netpoll *np) 157{ 158 if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller) 159 return; 160 161 /* Process pending work on NIC */ 162 np->dev->poll_controller(np->dev); 163 if (np->dev->poll) 164 poll_napi(np); 165 166 zap_completion_queue(); 167} 168 169static void refill_skbs(void) 170{ 171 struct sk_buff *skb; 172 unsigned long flags; 173 174 spin_lock_irqsave(&skb_list_lock, flags); 175 while (nr_skbs < MAX_SKBS) { 176 skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC); 177 if (!skb) 178 break; 179 180 skb->next = skbs; 181 skbs = skb; 182 nr_skbs++; 183 } 184 spin_unlock_irqrestore(&skb_list_lock, flags); 185} 186 187static void zap_completion_queue(void) 188{ 189 unsigned long flags; 190 struct softnet_data *sd = &get_cpu_var(softnet_data); 191 192 if (sd->completion_queue) { 193 struct sk_buff *clist; 194 195 local_irq_save(flags); 196 clist = sd->completion_queue; 197 sd->completion_queue = NULL; 198 local_irq_restore(flags); 199 200 while (clist != NULL) { 201 struct sk_buff *skb = clist; 202 clist = clist->next; 203 if(skb->destructor) 204 dev_kfree_skb_any(skb); /* put this one back */ 205 else 206 __kfree_skb(skb); 207 } 208 } 209 210 put_cpu_var(softnet_data); 211} 212 213static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve) 214{ 215 int once = 1, count = 0; 216 unsigned long flags; 217 struct sk_buff *skb = NULL; 218 219 zap_completion_queue(); 220repeat: 221 if (nr_skbs < MAX_SKBS) 222 refill_skbs(); 223 224 skb = alloc_skb(len, GFP_ATOMIC); 225 226 if (!skb) { 227 spin_lock_irqsave(&skb_list_lock, flags); 228 skb = skbs; 229 if (skb) { 230 skbs = skb->next; 231 skb->next = NULL; 232 nr_skbs--; 233 } 234 spin_unlock_irqrestore(&skb_list_lock, flags); 235 } 236 237 if(!skb) { 238 count++; 239 if (once && (count == 1000000)) { 240 printk("out of netpoll skbs!\n"); 241 once = 0; 242 } 243 netpoll_poll(np); 244 goto repeat; 245 } 246 247 atomic_set(&skb->users, 1); 248 skb_reserve(skb, reserve); 249 return skb; 250} 251 252static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) 253{ 254 int status; 255 struct netpoll_info *npinfo; 256 257 if (!np || !np->dev || !netif_running(np->dev)) { 258 __kfree_skb(skb); 259 return; 260 } 261 262 npinfo = np->dev->npinfo; 263 264 /* avoid recursion */ 265 if (npinfo->poll_owner == smp_processor_id() || 266 np->dev->xmit_lock_owner == smp_processor_id()) { 267 if (np->drop) 268 np->drop(skb); 269 else 270 __kfree_skb(skb); 271 return; 272 } 273 274 do { 275 npinfo->tries--; 276 spin_lock(&np->dev->xmit_lock); 277 np->dev->xmit_lock_owner = smp_processor_id(); 278 279 /* 280 * network drivers do not expect to be called if the queue is 281 * stopped. 282 */ 283 if (netif_queue_stopped(np->dev)) { 284 np->dev->xmit_lock_owner = -1; 285 spin_unlock(&np->dev->xmit_lock); 286 netpoll_poll(np); 287 udelay(50); 288 continue; 289 } 290 291 status = np->dev->hard_start_xmit(skb, np->dev); 292 np->dev->xmit_lock_owner = -1; 293 spin_unlock(&np->dev->xmit_lock); 294 295 /* success */ 296 if(!status) { 297 npinfo->tries = MAX_RETRIES; /* reset */ 298 return; 299 } 300 301 /* transmit busy */ 302 netpoll_poll(np); 303 udelay(50); 304 } while (npinfo->tries > 0); 305} 306 307void netpoll_send_udp(struct netpoll *np, const char *msg, int len) 308{ 309 int total_len, eth_len, ip_len, udp_len; 310 struct sk_buff *skb; 311 struct udphdr *udph; 312 struct iphdr *iph; 313 struct ethhdr *eth; 314 315 udp_len = len + sizeof(*udph); 316 ip_len = eth_len = udp_len + sizeof(*iph); 317 total_len = eth_len + ETH_HLEN + NET_IP_ALIGN; 318 319 skb = find_skb(np, total_len, total_len - len); 320 if (!skb) 321 return; 322 323 memcpy(skb->data, msg, len); 324 skb->len += len; 325 326 udph = (struct udphdr *) skb_push(skb, sizeof(*udph)); 327 udph->source = htons(np->local_port); 328 udph->dest = htons(np->remote_port); 329 udph->len = htons(udp_len); 330 udph->check = 0; 331 332 iph = (struct iphdr *)skb_push(skb, sizeof(*iph)); 333 334 /* iph->version = 4; iph->ihl = 5; */ 335 put_unaligned(0x45, (unsigned char *)iph); 336 iph->tos = 0; 337 put_unaligned(htons(ip_len), &(iph->tot_len)); 338 iph->id = 0; 339 iph->frag_off = 0; 340 iph->ttl = 64; 341 iph->protocol = IPPROTO_UDP; 342 iph->check = 0; 343 put_unaligned(htonl(np->local_ip), &(iph->saddr)); 344 put_unaligned(htonl(np->remote_ip), &(iph->daddr)); 345 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); 346 347 eth = (struct ethhdr *) skb_push(skb, ETH_HLEN); 348 349 eth->h_proto = htons(ETH_P_IP); 350 memcpy(eth->h_source, np->local_mac, 6); 351 memcpy(eth->h_dest, np->remote_mac, 6); 352 353 skb->dev = np->dev; 354 355 netpoll_send_skb(np, skb); 356} 357 358static void arp_reply(struct sk_buff *skb) 359{ 360 struct netpoll_info *npinfo = skb->dev->npinfo; 361 struct arphdr *arp; 362 unsigned char *arp_ptr; 363 int size, type = ARPOP_REPLY, ptype = ETH_P_ARP; 364 u32 sip, tip; 365 struct sk_buff *send_skb; 366 struct netpoll *np = NULL; 367 368 if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev) 369 np = npinfo->rx_np; 370 if (!np) 371 return; 372 373 /* No arp on this interface */ 374 if (skb->dev->flags & IFF_NOARP) 375 return; 376 377 if (!pskb_may_pull(skb, (sizeof(struct arphdr) + 378 (2 * skb->dev->addr_len) + 379 (2 * sizeof(u32))))) 380 return; 381 382 skb->h.raw = skb->nh.raw = skb->data; 383 arp = skb->nh.arph; 384 385 if ((arp->ar_hrd != htons(ARPHRD_ETHER) && 386 arp->ar_hrd != htons(ARPHRD_IEEE802)) || 387 arp->ar_pro != htons(ETH_P_IP) || 388 arp->ar_op != htons(ARPOP_REQUEST)) 389 return; 390 391 arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len; 392 memcpy(&sip, arp_ptr, 4); 393 arp_ptr += 4 + skb->dev->addr_len; 394 memcpy(&tip, arp_ptr, 4); 395 396 /* Should we ignore arp? */ 397 if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip)) 398 return; 399 400 size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4); 401 send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev), 402 LL_RESERVED_SPACE(np->dev)); 403 404 if (!send_skb) 405 return; 406 407 send_skb->nh.raw = send_skb->data; 408 arp = (struct arphdr *) skb_put(send_skb, size); 409 send_skb->dev = skb->dev; 410 send_skb->protocol = htons(ETH_P_ARP); 411 412 /* Fill the device header for the ARP frame */ 413 414 if (np->dev->hard_header && 415 np->dev->hard_header(send_skb, skb->dev, ptype, 416 np->remote_mac, np->local_mac, 417 send_skb->len) < 0) { 418 kfree_skb(send_skb); 419 return; 420 } 421 422 /* 423 * Fill out the arp protocol part. 424 * 425 * we only support ethernet device type, 426 * which (according to RFC 1390) should always equal 1 (Ethernet). 427 */ 428 429 arp->ar_hrd = htons(np->dev->type); 430 arp->ar_pro = htons(ETH_P_IP); 431 arp->ar_hln = np->dev->addr_len; 432 arp->ar_pln = 4; 433 arp->ar_op = htons(type); 434 435 arp_ptr=(unsigned char *)(arp + 1); 436 memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len); 437 arp_ptr += np->dev->addr_len; 438 memcpy(arp_ptr, &tip, 4); 439 arp_ptr += 4; 440 memcpy(arp_ptr, np->remote_mac, np->dev->addr_len); 441 arp_ptr += np->dev->addr_len; 442 memcpy(arp_ptr, &sip, 4); 443 444 netpoll_send_skb(np, send_skb); 445} 446 447int __netpoll_rx(struct sk_buff *skb) 448{ 449 int proto, len, ulen; 450 struct iphdr *iph; 451 struct udphdr *uh; 452 struct netpoll *np = skb->dev->npinfo->rx_np; 453 454 if (!np) 455 goto out; 456 if (skb->dev->type != ARPHRD_ETHER) 457 goto out; 458 459 /* check if netpoll clients need ARP */ 460 if (skb->protocol == __constant_htons(ETH_P_ARP) && 461 atomic_read(&trapped)) { 462 arp_reply(skb); 463 return 1; 464 } 465 466 proto = ntohs(eth_hdr(skb)->h_proto); 467 if (proto != ETH_P_IP) 468 goto out; 469 if (skb->pkt_type == PACKET_OTHERHOST) 470 goto out; 471 if (skb_shared(skb)) 472 goto out; 473 474 iph = (struct iphdr *)skb->data; 475 if (!pskb_may_pull(skb, sizeof(struct iphdr))) 476 goto out; 477 if (iph->ihl < 5 || iph->version != 4) 478 goto out; 479 if (!pskb_may_pull(skb, iph->ihl*4)) 480 goto out; 481 if (ip_fast_csum((u8 *)iph, iph->ihl) != 0) 482 goto out; 483 484 len = ntohs(iph->tot_len); 485 if (skb->len < len || len < iph->ihl*4) 486 goto out; 487 488 if (iph->protocol != IPPROTO_UDP) 489 goto out; 490 491 len -= iph->ihl*4; 492 uh = (struct udphdr *)(((char *)iph) + iph->ihl*4); 493 ulen = ntohs(uh->len); 494 495 if (ulen != len) 496 goto out; 497 if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr)) 498 goto out; 499 if (np->local_ip && np->local_ip != ntohl(iph->daddr)) 500 goto out; 501 if (np->remote_ip && np->remote_ip != ntohl(iph->saddr)) 502 goto out; 503 if (np->local_port && np->local_port != ntohs(uh->dest)) 504 goto out; 505 506 np->rx_hook(np, ntohs(uh->source), 507 (char *)(uh+1), 508 ulen - sizeof(struct udphdr)); 509 510 kfree_skb(skb); 511 return 1; 512 513out: 514 if (atomic_read(&trapped)) { 515 kfree_skb(skb); 516 return 1; 517 } 518 519 return 0; 520} 521 522int netpoll_parse_options(struct netpoll *np, char *opt) 523{ 524 char *cur=opt, *delim; 525 526 if(*cur != '@') { 527 if ((delim = strchr(cur, '@')) == NULL) 528 goto parse_failed; 529 *delim=0; 530 np->local_port=simple_strtol(cur, NULL, 10); 531 cur=delim; 532 } 533 cur++; 534 printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port); 535 536 if(*cur != '/') { 537 if ((delim = strchr(cur, '/')) == NULL) 538 goto parse_failed; 539 *delim=0; 540 np->local_ip=ntohl(in_aton(cur)); 541 cur=delim; 542 543 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n", 544 np->name, HIPQUAD(np->local_ip)); 545 } 546 cur++; 547 548 if ( *cur != ',') { 549 /* parse out dev name */ 550 if ((delim = strchr(cur, ',')) == NULL) 551 goto parse_failed; 552 *delim=0; 553 strlcpy(np->dev_name, cur, sizeof(np->dev_name)); 554 cur=delim; 555 } 556 cur++; 557 558 printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name); 559 560 if ( *cur != '@' ) { 561 /* dst port */ 562 if ((delim = strchr(cur, '@')) == NULL) 563 goto parse_failed; 564 *delim=0; 565 np->remote_port=simple_strtol(cur, NULL, 10); 566 cur=delim; 567 } 568 cur++; 569 printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port); 570 571 /* dst ip */ 572 if ((delim = strchr(cur, '/')) == NULL) 573 goto parse_failed; 574 *delim=0; 575 np->remote_ip=ntohl(in_aton(cur)); 576 cur=delim+1; 577 578 printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n", 579 np->name, HIPQUAD(np->remote_ip)); 580 581 if( *cur != 0 ) 582 { 583 /* MAC address */ 584 if ((delim = strchr(cur, ':')) == NULL) 585 goto parse_failed; 586 *delim=0; 587 np->remote_mac[0]=simple_strtol(cur, NULL, 16); 588 cur=delim+1; 589 if ((delim = strchr(cur, ':')) == NULL) 590 goto parse_failed; 591 *delim=0; 592 np->remote_mac[1]=simple_strtol(cur, NULL, 16); 593 cur=delim+1; 594 if ((delim = strchr(cur, ':')) == NULL) 595 goto parse_failed; 596 *delim=0; 597 np->remote_mac[2]=simple_strtol(cur, NULL, 16); 598 cur=delim+1; 599 if ((delim = strchr(cur, ':')) == NULL) 600 goto parse_failed; 601 *delim=0; 602 np->remote_mac[3]=simple_strtol(cur, NULL, 16); 603 cur=delim+1; 604 if ((delim = strchr(cur, ':')) == NULL) 605 goto parse_failed; 606 *delim=0; 607 np->remote_mac[4]=simple_strtol(cur, NULL, 16); 608 cur=delim+1; 609 np->remote_mac[5]=simple_strtol(cur, NULL, 16); 610 } 611 612 printk(KERN_INFO "%s: remote ethernet address " 613 "%02x:%02x:%02x:%02x:%02x:%02x\n", 614 np->name, 615 np->remote_mac[0], 616 np->remote_mac[1], 617 np->remote_mac[2], 618 np->remote_mac[3], 619 np->remote_mac[4], 620 np->remote_mac[5]); 621 622 return 0; 623 624 parse_failed: 625 printk(KERN_INFO "%s: couldn't parse config at %s!\n", 626 np->name, cur); 627 return -1; 628} 629 630int netpoll_setup(struct netpoll *np) 631{ 632 struct net_device *ndev = NULL; 633 struct in_device *in_dev; 634 struct netpoll_info *npinfo; 635 unsigned long flags; 636 637 if (np->dev_name) 638 ndev = dev_get_by_name(np->dev_name); 639 if (!ndev) { 640 printk(KERN_ERR "%s: %s doesn't exist, aborting.\n", 641 np->name, np->dev_name); 642 return -1; 643 } 644 645 np->dev = ndev; 646 if (!ndev->npinfo) { 647 npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL); 648 if (!npinfo) 649 goto release; 650 651 npinfo->rx_flags = 0; 652 npinfo->rx_np = NULL; 653 spin_lock_init(&npinfo->poll_lock); 654 npinfo->poll_owner = -1; 655 npinfo->tries = MAX_RETRIES; 656 spin_lock_init(&npinfo->rx_lock); 657 } else 658 npinfo = ndev->npinfo; 659 660 if (!ndev->poll_controller) { 661 printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n", 662 np->name, np->dev_name); 663 goto release; 664 } 665 666 if (!netif_running(ndev)) { 667 unsigned long atmost, atleast; 668 669 printk(KERN_INFO "%s: device %s not up yet, forcing it\n", 670 np->name, np->dev_name); 671 672 rtnl_lock(); 673 if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) { 674 printk(KERN_ERR "%s: failed to open %s\n", 675 np->name, np->dev_name); 676 rtnl_unlock(); 677 goto release; 678 } 679 rtnl_unlock(); 680 681 atleast = jiffies + HZ/10; 682 atmost = jiffies + 4*HZ; 683 while (!netif_carrier_ok(ndev)) { 684 if (time_after(jiffies, atmost)) { 685 printk(KERN_NOTICE 686 "%s: timeout waiting for carrier\n", 687 np->name); 688 break; 689 } 690 cond_resched(); 691 } 692 693 /* If carrier appears to come up instantly, we don't 694 * trust it and pause so that we don't pump all our 695 * queued console messages into the bitbucket. 696 */ 697 698 if (time_before(jiffies, atleast)) { 699 printk(KERN_NOTICE "%s: carrier detect appears" 700 " untrustworthy, waiting 4 seconds\n", 701 np->name); 702 msleep(4000); 703 } 704 } 705 706 if (is_zero_ether_addr(np->local_mac) && ndev->dev_addr) 707 memcpy(np->local_mac, ndev->dev_addr, 6); 708 709 if (!np->local_ip) { 710 rcu_read_lock(); 711 in_dev = __in_dev_get_rcu(ndev); 712 713 if (!in_dev || !in_dev->ifa_list) { 714 rcu_read_unlock(); 715 printk(KERN_ERR "%s: no IP address for %s, aborting\n", 716 np->name, np->dev_name); 717 goto release; 718 } 719 720 np->local_ip = ntohl(in_dev->ifa_list->ifa_local); 721 rcu_read_unlock(); 722 printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n", 723 np->name, HIPQUAD(np->local_ip)); 724 } 725 726 if (np->rx_hook) { 727 spin_lock_irqsave(&npinfo->rx_lock, flags); 728 npinfo->rx_flags |= NETPOLL_RX_ENABLED; 729 npinfo->rx_np = np; 730 spin_unlock_irqrestore(&npinfo->rx_lock, flags); 731 } 732 733 /* fill up the skb queue */ 734 refill_skbs(); 735 736 /* last thing to do is link it to the net device structure */ 737 ndev->npinfo = npinfo; 738 739 /* avoid racing with NAPI reading npinfo */ 740 synchronize_rcu(); 741 742 return 0; 743 744 release: 745 if (!ndev->npinfo) 746 kfree(npinfo); 747 np->dev = NULL; 748 dev_put(ndev); 749 return -1; 750} 751 752void netpoll_cleanup(struct netpoll *np) 753{ 754 struct netpoll_info *npinfo; 755 unsigned long flags; 756 757 if (np->dev) { 758 npinfo = np->dev->npinfo; 759 if (npinfo && npinfo->rx_np == np) { 760 spin_lock_irqsave(&npinfo->rx_lock, flags); 761 npinfo->rx_np = NULL; 762 npinfo->rx_flags &= ~NETPOLL_RX_ENABLED; 763 spin_unlock_irqrestore(&npinfo->rx_lock, flags); 764 } 765 dev_put(np->dev); 766 } 767 768 np->dev = NULL; 769} 770 771int netpoll_trap(void) 772{ 773 return atomic_read(&trapped); 774} 775 776void netpoll_set_trap(int trap) 777{ 778 if (trap) 779 atomic_inc(&trapped); 780 else 781 atomic_dec(&trapped); 782} 783 784EXPORT_SYMBOL(netpoll_set_trap); 785EXPORT_SYMBOL(netpoll_trap); 786EXPORT_SYMBOL(netpoll_parse_options); 787EXPORT_SYMBOL(netpoll_setup); 788EXPORT_SYMBOL(netpoll_cleanup); 789EXPORT_SYMBOL(netpoll_send_udp); 790EXPORT_SYMBOL(netpoll_poll); 791EXPORT_SYMBOL(netpoll_queue); 792