drivers/net/netconsole.c

   1 /*
   2  *  linux/drivers/net/netconsole.c
   3  *
   4  *  Copyright (C) 2001  Ingo Molnar <[email protected]>
   5  *
   6  *  This file contains the implementation of an IRQ-safe, crash-safe
   7  *  kernel console implementation that outputs kernel messages to the
   8  *  network.
   9  *
  10  * Modification history:
  11  *
  12  * 2001-09-17    started by Ingo Molnar.
  13  * 2003-08-11    2.6 port by Matt Mackall
  14  *               simplified options
  15  *               generic card hooks
  16  *               works non-modular
  17  * 2003-09-07    rewritten with netpoll api
  18  */
  19
  20 /****************************************************************
  21  *      This program is free software; you can redistribute it and/or modify
  22  *      it under the terms of the GNU General Public License as published by
  23  *      the Free Software Foundation; either version 2, or (at your option)
  24  *      any later version.
  25  *
  26  *      This program is distributed in the hope that it will be useful,
  27  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29  *      GNU General Public License for more details.
  30  *
  31  *      You should have received a copy of the GNU General Public License
  32  *      along with this program; if not, write to the Free Software
  33  *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  34  *
  35  ****************************************************************/
  36
  37 #include <linux/mm.h>
  38 #include <linux/init.h>
  39 #include <linux/module.h>
  40 #include <linux/slab.h>
  41 #include <linux/console.h>
  42 #include <linux/moduleparam.h>
  43 #include <linux/string.h>
  44 #include <linux/netpoll.h>
  45 #include <linux/inet.h>
  46 #include <linux/configfs.h>
  47
  48 MODULE_AUTHOR("Maintainer: Matt Mackall <[email protected]>");
  49 MODULE_DESCRIPTION("Console driver for network interfaces");
  50 MODULE_LICENSE("GPL");
  51
  52 #define MAX_PARAM_LENGTH        256
  53 #define MAX_PRINT_CHUNK         1000
  54
  55 static char config[MAX_PARAM_LENGTH];
  56 module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
  57 MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
  58
  59 static bool oops_only = false;
  60 module_param(oops_only, bool, 0600);
  61 MODULE_PARM_DESC(oops_only, "Only log oops messages");
  62
  63 #ifndef MODULE
  64 static int __init option_setup(char *opt)
  65 {
  66         strlcpy(config, opt, MAX_PARAM_LENGTH);
  67         return 1;
  68 }
  69 __setup("netconsole=", option_setup);
  70 #endif  /* MODULE */
  71
  72 /* Linked list of all configured targets */
  73 static LIST_HEAD(target_list);
  74
  75 /* This needs to be a spinlock because write_msg() cannot sleep */
  76 static DEFINE_SPINLOCK(target_list_lock);
  77
  78 /**
  79  * struct netconsole_target - Represents a configured netconsole target.
  80  * @list:       Links this target into the target_list.
  81  * @item:       Links us into the configfs subsystem hierarchy.
  82  * @enabled:    On / off knob to enable / disable target.
  83  *              Visible from userspace (read-write).
  84  *              We maintain a strict 1:1 correspondence between this and
  85  *              whether the corresponding netpoll is active or inactive.
  86  *              Also, other parameters of a target may be modified at
  87  *              runtime only when it is disabled (enabled == 0).
  88  * @np:         The netpoll structure for this target.
  89  *              Contains the other userspace visible parameters:
  90  *              dev_name        (read-write)
  91  *              local_port      (read-write)
  92  *              remote_port     (read-write)
  93  *              local_ip        (read-write)
  94  *              remote_ip       (read-write)
  95  *              local_mac       (read-only)
  96  *              remote_mac      (read-write)
  97  */
  98 struct netconsole_target {
  99         struct list_head        list;
 100 #ifdef  CONFIG_NETCONSOLE_DYNAMIC
 101         struct config_item      item;
 102 #endif
 103         int                     enabled;
 104         struct netpoll          np;
 105 };
 106
 107 #ifdef  CONFIG_NETCONSOLE_DYNAMIC
 108
 109 static struct configfs_subsystem netconsole_subsys;
 110
 111 static int __init dynamic_netconsole_init(void)
 112 {
 113         config_group_init(&netconsole_subsys.su_group);
 114         mutex_init(&netconsole_subsys.su_mutex);
 115         return configfs_register_subsystem(&netconsole_subsys);
 116 }
 117
 118 static void __exit dynamic_netconsole_exit(void)
 119 {
 120         configfs_unregister_subsystem(&netconsole_subsys);
 121 }
 122
 123 /*
 124  * Targets that were created by parsing the boot/module option string
 125  * do not exist in the configfs hierarchy (and have NULL names) and will
 126  * never go away, so make these a no-op for them.
 127  */
 128 static void netconsole_target_get(struct netconsole_target *nt)
 129 {
 130         if (config_item_name(&nt->item))
 131                 config_item_get(&nt->item);
 132 }
 133
 134 static void netconsole_target_put(struct netconsole_target *nt)
 135 {
 136         if (config_item_name(&nt->item))
 137                 config_item_put(&nt->item);
 138 }
 139
 140 #else   /* !CONFIG_NETCONSOLE_DYNAMIC */
 141
 142 static int __init dynamic_netconsole_init(void)
 143 {
 144         return 0;
 145 }
 146
 147 static void __exit dynamic_netconsole_exit(void)
 148 {
 149 }
 150
 151 /*
 152  * No danger of targets going away from under us when dynamic
 153  * reconfigurability is off.
 154  */
 155 static void netconsole_target_get(struct netconsole_target *nt)
 156 {
 157 }
 158
 159 static void netconsole_target_put(struct netconsole_target *nt)
 160 {
 161 }
 162
 163 #endif  /* CONFIG_NETCONSOLE_DYNAMIC */
 164
 165 /* Allocate new target (from boot/module param) and setup netpoll for it */
 166 static struct netconsole_target *alloc_param_target(char *target_config)
 167 {
 168         int err = -ENOMEM;
 169         struct netconsole_target *nt;
 170
 171         /*
 172          * Allocate and initialize with defaults.
 173          * Note that these targets get their config_item fields zeroed-out.
 174          */
 175         nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 176         if (!nt)
 177                 goto fail;
 178
 179         nt->np.name = "netconsole";
 180         strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
 181         nt->np.local_port = 6665;
 182         nt->np.remote_port = 6666;
 183         memset(nt->np.remote_mac, 0xff, ETH_ALEN);
 184
 185         /* Parse parameters and setup netpoll */
 186         err = netpoll_parse_options(&nt->np, target_config);
 187         if (err)
 188                 goto fail;
 189
 190         err = netpoll_setup(&nt->np);
 191         if (err)
 192                 goto fail;
 193
 194         nt->enabled = 1;
 195
 196         return nt;
 197
 198 fail:
 199         kfree(nt);
 200         return ERR_PTR(err);
 201 }
 202
 203 /* Cleanup netpoll for given target (from boot/module param) and free it */
 204 static void free_param_target(struct netconsole_target *nt)
 205 {
 206         netpoll_cleanup(&nt->np);
 207         kfree(nt);
 208 }
 209
 210 #ifdef  CONFIG_NETCONSOLE_DYNAMIC
 211
 212 /*
 213  * Our subsystem hierarchy is:
 214  *
 215  * /sys/kernel/config/netconsole/
 216  *                              |
 217  *                              <target>/
 218  *                              |       enabled
 219  *                              |       dev_name
 220  *                              |       local_port
 221  *                              |       remote_port
 222  *                              |       local_ip
 223  *                              |       remote_ip
 224  *                              |       local_mac
 225  *                              |       remote_mac
 226  *                              |
 227  *                              <target>/...
 228  */
 229
 230 struct netconsole_target_attr {
 231         struct configfs_attribute       attr;
 232         ssize_t                         (*show)(struct netconsole_target *nt,
 233                                                 char *buf);
 234         ssize_t                         (*store)(struct netconsole_target *nt,
 235                                                  const char *buf,
 236                                                  size_t count);
 237 };
 238
 239 static struct netconsole_target *to_target(struct config_item *item)
 240 {
 241         return item ?
 242                 container_of(item, struct netconsole_target, item) :
 243                 NULL;
 244 }
 245
 246 /*
 247  * Attribute operations for netconsole_target.
 248  */
 249
 250 static ssize_t show_enabled(struct netconsole_target *nt, char *buf)
 251 {
 252         return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled);
 253 }
 254
 255 static ssize_t show_dev_name(struct netconsole_target *nt, char *buf)
 256 {
 257         return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name);
 258 }
 259
 260 static ssize_t show_local_port(struct netconsole_target *nt, char *buf)
 261 {
 262         return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.local_port);
 263 }
 264
 265 static ssize_t show_remote_port(struct netconsole_target *nt, char *buf)
 266 {
 267         return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.remote_port);
 268 }
 269
 270 static ssize_t show_local_ip(struct netconsole_target *nt, char *buf)
 271 {
 272         if (nt->np.ipv6)
 273                 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.local_ip.in6);
 274         else
 275                 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip);
 276 }
 277
 278 static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
 279 {
 280         if (nt->np.ipv6)
 281                 return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.remote_ip.in6);
 282         else
 283                 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
 284 }
 285
 286 static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
 287 {
 288         struct net_device *dev = nt->np.dev;
 289         static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 290
 291         return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
 292 }
 293
 294 static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
 295 {
 296         return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac);
 297 }
 298
 299 /*
 300  * This one is special -- targets created through the configfs interface
 301  * are not enabled (and the corresponding netpoll activated) by default.
 302  * The user is expected to set the desired parameters first (which
 303  * would enable him to dynamically add new netpoll targets for new
 304  * network interfaces as and when they come up).
 305  */
 306 static ssize_t store_enabled(struct netconsole_target *nt,
 307                              const char *buf,
 308                              size_t count)
 309 {
 310         int enabled;
 311         int err;
 312
 313         err = kstrtoint(buf, 10, &enabled);
 314         if (err < 0)
 315                 return err;
 316         if (enabled < 0 || enabled > 1)
 317                 return -EINVAL;
 318         if (enabled == nt->enabled) {
 319                 printk(KERN_INFO "netconsole: network logging has already %s\n",
 320                                 nt->enabled ? "started" : "stopped");
 321                 return -EINVAL;
 322         }
 323
 324         if (enabled) {  /* 1 */
 325
 326                 /*
 327                  * Skip netpoll_parse_options() -- all the attributes are
 328                  * already configured via configfs. Just print them out.
 329                  */
 330                 netpoll_print_options(&nt->np);
 331
 332                 err = netpoll_setup(&nt->np);
 333                 if (err)
 334                         return err;
 335
 336                 printk(KERN_INFO "netconsole: network logging started\n");
 337
 338         } else {        /* 0 */
 339                 netpoll_cleanup(&nt->np);
 340         }
 341
 342         nt->enabled = enabled;
 343
 344         return strnlen(buf, count);
 345 }
 346
 347 static ssize_t store_dev_name(struct netconsole_target *nt,
 348                               const char *buf,
 349                               size_t count)
 350 {
 351         size_t len;
 352
 353         if (nt->enabled) {
 354                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 355                                 "disable to update parameters\n",
 356                                 config_item_name(&nt->item));
 357                 return -EINVAL;
 358         }
 359
 360         strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
 361
 362         /* Get rid of possible trailing newline from echo(1) */
 363         len = strnlen(nt->np.dev_name, IFNAMSIZ);
 364         if (nt->np.dev_name[len - 1] == '\n')
 365                 nt->np.dev_name[len - 1] = '\0';
 366
 367         return strnlen(buf, count);
 368 }
 369
 370 static ssize_t store_local_port(struct netconsole_target *nt,
 371                                 const char *buf,
 372                                 size_t count)
 373 {
 374         int rv;
 375
 376         if (nt->enabled) {
 377                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 378                                 "disable to update parameters\n",
 379                                 config_item_name(&nt->item));
 380                 return -EINVAL;
 381         }
 382
 383         rv = kstrtou16(buf, 10, &nt->np.local_port);
 384         if (rv < 0)
 385                 return rv;
 386         return strnlen(buf, count);
 387 }
 388
 389 static ssize_t store_remote_port(struct netconsole_target *nt,
 390                                  const char *buf,
 391                                  size_t count)
 392 {
 393         int rv;
 394
 395         if (nt->enabled) {
 396                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 397                                 "disable to update parameters\n",
 398                                 config_item_name(&nt->item));
 399                 return -EINVAL;
 400         }
 401
 402         rv = kstrtou16(buf, 10, &nt->np.remote_port);
 403         if (rv < 0)
 404                 return rv;
 405         return strnlen(buf, count);
 406 }
 407
 408 static ssize_t store_local_ip(struct netconsole_target *nt,
 409                               const char *buf,
 410                               size_t count)
 411 {
 412         if (nt->enabled) {
 413                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 414                                 "disable to update parameters\n",
 415                                 config_item_name(&nt->item));
 416                 return -EINVAL;
 417         }
 418
 419         if (strnchr(buf, count, ':')) {
 420                 const char *end;
 421                 if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
 422                         if (*end && *end != '\n') {
 423                                 printk(KERN_ERR "netconsole: invalid IPv6 address at: <%c>\n", *end);
 424                                 return -EINVAL;
 425                         }
 426                         nt->np.ipv6 = true;
 427                 } else
 428                         return -EINVAL;
 429         } else {
 430                 if (!nt->np.ipv6) {
 431                         nt->np.local_ip.ip = in_aton(buf);
 432                 } else
 433                         return -EINVAL;
 434         }
 435
 436         return strnlen(buf, count);
 437 }
 438
 439 static ssize_t store_remote_ip(struct netconsole_target *nt,
 440                                const char *buf,
 441                                size_t count)
 442 {
 443         if (nt->enabled) {
 444                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 445                                 "disable to update parameters\n",
 446                                 config_item_name(&nt->item));
 447                 return -EINVAL;
 448         }
 449
 450         if (strnchr(buf, count, ':')) {
 451                 const char *end;
 452                 if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
 453                         if (*end && *end != '\n') {
 454                                 printk(KERN_ERR "netconsole: invalid IPv6 address at: <%c>\n", *end);
 455                                 return -EINVAL;
 456                         }
 457                         nt->np.ipv6 = true;
 458                 } else
 459                         return -EINVAL;
 460         } else {
 461                 if (!nt->np.ipv6) {
 462                         nt->np.remote_ip.ip = in_aton(buf);
 463                 } else
 464                         return -EINVAL;
 465         }
 466
 467         return strnlen(buf, count);
 468 }
 469
 470 static ssize_t store_remote_mac(struct netconsole_target *nt,
 471                                 const char *buf,
 472                                 size_t count)
 473 {
 474         u8 remote_mac[ETH_ALEN];
 475
 476         if (nt->enabled) {
 477                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 478                                 "disable to update parameters\n",
 479                                 config_item_name(&nt->item));
 480                 return -EINVAL;
 481         }
 482
 483         if (!mac_pton(buf, remote_mac))
 484                 return -EINVAL;
 485         if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
 486                 return -EINVAL;
 487         memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
 488
 489         return strnlen(buf, count);
 490 }
 491
 492 /*
 493  * Attribute definitions for netconsole_target.
 494  */
 495
 496 #define NETCONSOLE_TARGET_ATTR_RO(_name)                                \
 497 static struct netconsole_target_attr netconsole_target_##_name =        \
 498         __CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
 499
 500 #define NETCONSOLE_TARGET_ATTR_RW(_name)                                \
 501 static struct netconsole_target_attr netconsole_target_##_name =        \
 502         __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
 503
 504 NETCONSOLE_TARGET_ATTR_RW(enabled);
 505 NETCONSOLE_TARGET_ATTR_RW(dev_name);
 506 NETCONSOLE_TARGET_ATTR_RW(local_port);
 507 NETCONSOLE_TARGET_ATTR_RW(remote_port);
 508 NETCONSOLE_TARGET_ATTR_RW(local_ip);
 509 NETCONSOLE_TARGET_ATTR_RW(remote_ip);
 510 NETCONSOLE_TARGET_ATTR_RO(local_mac);
 511 NETCONSOLE_TARGET_ATTR_RW(remote_mac);
 512
 513 static struct configfs_attribute *netconsole_target_attrs[] = {
 514         &netconsole_target_enabled.attr,
 515         &netconsole_target_dev_name.attr,
 516         &netconsole_target_local_port.attr,
 517         &netconsole_target_remote_port.attr,
 518         &netconsole_target_local_ip.attr,
 519         &netconsole_target_remote_ip.attr,
 520         &netconsole_target_local_mac.attr,
 521         &netconsole_target_remote_mac.attr,
 522         NULL,
 523 };
 524
 525 /*
 526  * Item operations and type for netconsole_target.
 527  */
 528
 529 static void netconsole_target_release(struct config_item *item)
 530 {
 531         kfree(to_target(item));
 532 }
 533
 534 static ssize_t netconsole_target_attr_show(struct config_item *item,
 535                                            struct configfs_attribute *attr,
 536                                            char *buf)
 537 {
 538         ssize_t ret = -EINVAL;
 539         struct netconsole_target *nt = to_target(item);
 540         struct netconsole_target_attr *na =
 541                 container_of(attr, struct netconsole_target_attr, attr);
 542
 543         if (na->show)
 544                 ret = na->show(nt, buf);
 545
 546         return ret;
 547 }
 548
 549 static ssize_t netconsole_target_attr_store(struct config_item *item,
 550                                             struct configfs_attribute *attr,
 551                                             const char *buf,
 552                                             size_t count)
 553 {
 554         ssize_t ret = -EINVAL;
 555         struct netconsole_target *nt = to_target(item);
 556         struct netconsole_target_attr *na =
 557                 container_of(attr, struct netconsole_target_attr, attr);
 558
 559         if (na->store)
 560                 ret = na->store(nt, buf, count);
 561
 562         return ret;
 563 }
 564
 565 static struct configfs_item_operations netconsole_target_item_ops = {
 566         .release                = netconsole_target_release,
 567         .show_attribute         = netconsole_target_attr_show,
 568         .store_attribute        = netconsole_target_attr_store,
 569 };
 570
 571 static struct config_item_type netconsole_target_type = {
 572         .ct_attrs               = netconsole_target_attrs,
 573         .ct_item_ops            = &netconsole_target_item_ops,
 574         .ct_owner               = THIS_MODULE,
 575 };
 576
 577 /*
 578  * Group operations and type for netconsole_subsys.
 579  */
 580
 581 static struct config_item *make_netconsole_target(struct config_group *group,
 582                                                   const char *name)
 583 {
 584         unsigned long flags;
 585         struct netconsole_target *nt;
 586
 587         /*
 588          * Allocate and initialize with defaults.
 589          * Target is disabled at creation (enabled == 0).
 590          */
 591         nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 592         if (!nt)
 593                 return ERR_PTR(-ENOMEM);
 594
 595         nt->np.name = "netconsole";
 596         strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
 597         nt->np.local_port = 6665;
 598         nt->np.remote_port = 6666;
 599         memset(nt->np.remote_mac, 0xff, ETH_ALEN);
 600
 601         /* Initialize the config_item member */
 602         config_item_init_type_name(&nt->item, name, &netconsole_target_type);
 603
 604         /* Adding, but it is disabled */
 605         spin_lock_irqsave(&target_list_lock, flags);
 606         list_add(&nt->list, &target_list);
 607         spin_unlock_irqrestore(&target_list_lock, flags);
 608
 609         return &nt->item;
 610 }
 611
 612 static void drop_netconsole_target(struct config_group *group,
 613                                    struct config_item *item)
 614 {
 615         unsigned long flags;
 616         struct netconsole_target *nt = to_target(item);
 617
 618         spin_lock_irqsave(&target_list_lock, flags);
 619         list_del(&nt->list);
 620         spin_unlock_irqrestore(&target_list_lock, flags);
 621
 622         /*
 623          * The target may have never been enabled, or was manually disabled
 624          * before being removed so netpoll may have already been cleaned up.
 625          */
 626         if (nt->enabled)
 627                 netpoll_cleanup(&nt->np);
 628
 629         config_item_put(&nt->item);
 630 }
 631
 632 static struct configfs_group_operations netconsole_subsys_group_ops = {
 633         .make_item      = make_netconsole_target,
 634         .drop_item      = drop_netconsole_target,
 635 };
 636
 637 static struct config_item_type netconsole_subsys_type = {
 638         .ct_group_ops   = &netconsole_subsys_group_ops,
 639         .ct_owner       = THIS_MODULE,
 640 };
 641
 642 /* The netconsole configfs subsystem */
 643 static struct configfs_subsystem netconsole_subsys = {
 644         .su_group       = {
 645                 .cg_item        = {
 646                         .ci_namebuf     = "netconsole",
 647                         .ci_type        = &netconsole_subsys_type,
 648                 },
 649         },
 650 };
 651
 652 #endif  /* CONFIG_NETCONSOLE_DYNAMIC */
 653
 654 /* Handle network interface device notifications */
 655 static int netconsole_netdev_event(struct notifier_block *this,
 656                                    unsigned long event,
 657                                    void *ptr)
 658 {
 659         unsigned long flags;
 660         struct netconsole_target *nt;
 661         struct net_device *dev = ptr;
 662         bool stopped = false;
 663
 664         if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
 665               event == NETDEV_RELEASE || event == NETDEV_JOIN))
 666                 goto done;
 667
 668         spin_lock_irqsave(&target_list_lock, flags);
 669         list_for_each_entry(nt, &target_list, list) {
 670                 netconsole_target_get(nt);
 671                 if (nt->np.dev == dev) {
 672                         switch (event) {
 673                         case NETDEV_CHANGENAME:
 674                                 strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
 675                                 break;
 676                         case NETDEV_RELEASE:
 677                         case NETDEV_JOIN:
 678                         case NETDEV_UNREGISTER:
 679                                 /*
 680                                  * rtnl_lock already held
 681                                  */
 682                                 if (nt->np.dev) {
 683                                         __netpoll_cleanup(&nt->np);
 684                                         dev_put(nt->np.dev);
 685                                         nt->np.dev = NULL;
 686                                 }
 687                                 nt->enabled = 0;
 688                                 stopped = true;
 689                                 break;
 690                         }
 691                 }
 692                 netconsole_target_put(nt);
 693         }
 694         spin_unlock_irqrestore(&target_list_lock, flags);
 695         if (stopped) {
 696                 printk(KERN_INFO "netconsole: network logging stopped on "
 697                        "interface %s as it ", dev->name);
 698                 switch (event) {
 699                 case NETDEV_UNREGISTER:
 700                         printk(KERN_CONT "unregistered\n");
 701                         break;
 702                 case NETDEV_RELEASE:
 703                         printk(KERN_CONT "released slaves\n");
 704                         break;
 705                 case NETDEV_JOIN:
 706                         printk(KERN_CONT "is joining a master device\n");
 707                         break;
 708                 }
 709         }
 710
 711 done:
 712         return NOTIFY_DONE;
 713 }
 714
 715 static struct notifier_block netconsole_netdev_notifier = {
 716         .notifier_call  = netconsole_netdev_event,
 717 };
 718
 719 static void write_msg(struct console *con, const char *msg, unsigned int len)
 720 {
 721         int frag, left;
 722         unsigned long flags;
 723         struct netconsole_target *nt;
 724         const char *tmp;
 725
 726         if (oops_only && !oops_in_progress)
 727                 return;
 728         /* Avoid taking lock and disabling interrupts unnecessarily */
 729         if (list_empty(&target_list))
 730                 return;
 731
 732         spin_lock_irqsave(&target_list_lock, flags);
 733         list_for_each_entry(nt, &target_list, list) {
 734                 netconsole_target_get(nt);
 735                 if (nt->enabled && netif_running(nt->np.dev)) {
 736                         /*
 737                          * We nest this inside the for-each-target loop above
 738                          * so that we're able to get as much logging out to
 739                          * at least one target if we die inside here, instead
 740                          * of unnecessarily keeping all targets in lock-step.
 741                          */
 742                         tmp = msg;
 743                         for (left = len; left;) {
 744                                 frag = min(left, MAX_PRINT_CHUNK);
 745                                 netpoll_send_udp(&nt->np, tmp, frag);
 746                                 tmp += frag;
 747                                 left -= frag;
 748                         }
 749                 }
 750                 netconsole_target_put(nt);
 751         }
 752         spin_unlock_irqrestore(&target_list_lock, flags);
 753 }
 754
 755 static struct console netconsole = {
 756         .name   = "netcon",
 757         .flags  = CON_ENABLED,
 758         .write  = write_msg,
 759 };
 760
 761 static int __init init_netconsole(void)
 762 {
 763         int err;
 764         struct netconsole_target *nt, *tmp;
 765         unsigned long flags;
 766         char *target_config;
 767         char *input = config;
 768
 769         if (strnlen(input, MAX_PARAM_LENGTH)) {
 770                 while ((target_config = strsep(&input, ";"))) {
 771                         nt = alloc_param_target(target_config);
 772                         if (IS_ERR(nt)) {
 773                                 err = PTR_ERR(nt);
 774                                 goto fail;
 775                         }
 776                         /* Dump existing printks when we register */
 777                         netconsole.flags |= CON_PRINTBUFFER;
 778
 779                         spin_lock_irqsave(&target_list_lock, flags);
 780                         list_add(&nt->list, &target_list);
 781                         spin_unlock_irqrestore(&target_list_lock, flags);
 782                 }
 783         }
 784
 785         err = register_netdevice_notifier(&netconsole_netdev_notifier);
 786         if (err)
 787                 goto fail;
 788
 789         err = dynamic_netconsole_init();
 790         if (err)
 791                 goto undonotifier;
 792
 793         register_console(&netconsole);
 794         printk(KERN_INFO "netconsole: network logging started\n");
 795
 796         return err;
 797
 798 undonotifier:
 799         unregister_netdevice_notifier(&netconsole_netdev_notifier);
 800
 801 fail:
 802         printk(KERN_ERR "netconsole: cleaning up\n");
 803
 804         /*
 805          * Remove all targets and destroy them (only targets created
 806          * from the boot/module option exist here). Skipping the list
 807          * lock is safe here, and netpoll_cleanup() will sleep.
 808          */
 809         list_for_each_entry_safe(nt, tmp, &target_list, list) {
 810                 list_del(&nt->list);
 811                 free_param_target(nt);
 812         }
 813
 814         return err;
 815 }
 816
 817 static void __exit cleanup_netconsole(void)
 818 {
 819         struct netconsole_target *nt, *tmp;
 820
 821         unregister_console(&netconsole);
 822         dynamic_netconsole_exit();
 823         unregister_netdevice_notifier(&netconsole_netdev_notifier);
 824
 825         /*
 826          * Targets created via configfs pin references on our module
 827          * and would first be rmdir(2)'ed from userspace. We reach
 828          * here only when they are already destroyed, and only those
 829          * created from the boot/module option are left, so remove and
 830          * destroy them. Skipping the list lock is safe here, and
 831          * netpoll_cleanup() will sleep.
 832          */
 833         list_for_each_entry_safe(nt, tmp, &target_list, list) {
 834                 list_del(&nt->list);
 835                 free_param_target(nt);
 836         }
 837 }
 838
 839 /*
 840  * Use late_initcall to ensure netconsole is
 841  * initialized after network device driver if built-in.
 842  *
 843  * late_initcall() and module_init() are identical if built as module.
 844  */
 845 late_initcall(init_netconsole);
 846 module_exit(cleanup_netconsole);