Pileus Git - ~andy/linux/blob - drivers/net/netconsole.c

   1 /*
   2  *  linux/drivers/net/netconsole.c
   3  *
   4  *  Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
   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 <mpm@selenic.com>");
  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, "%pI4\n", &nt->np.local_ip);
 274 }
 275
 276 static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
 277 {
 278         if (!nt->np.ipv6)
 279                 return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
 280 }
 281
 282 static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
 283 {
 284         struct net_device *dev = nt->np.dev;
 285         static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 286
 287         return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
 288 }
 289
 290 static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
 291 {
 292         return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac);
 293 }
 294
 295 /*
 296  * This one is special -- targets created through the configfs interface
 297  * are not enabled (and the corresponding netpoll activated) by default.
 298  * The user is expected to set the desired parameters first (which
 299  * would enable him to dynamically add new netpoll targets for new
 300  * network interfaces as and when they come up).
 301  */
 302 static ssize_t store_enabled(struct netconsole_target *nt,
 303                              const char *buf,
 304                              size_t count)
 305 {
 306         int enabled;
 307         int err;
 308
 309         err = kstrtoint(buf, 10, &enabled);
 310         if (err < 0)
 311                 return err;
 312         if (enabled < 0 || enabled > 1)
 313                 return -EINVAL;
 314         if (enabled == nt->enabled) {
 315                 printk(KERN_INFO "netconsole: network logging has already %s\n",
 316                                 nt->enabled ? "started" : "stopped");
 317                 return -EINVAL;
 318         }
 319
 320         if (enabled) {  /* 1 */
 321
 322                 /*
 323                  * Skip netpoll_parse_options() -- all the attributes are
 324                  * already configured via configfs. Just print them out.
 325                  */
 326                 netpoll_print_options(&nt->np);
 327
 328                 err = netpoll_setup(&nt->np);
 329                 if (err)
 330                         return err;
 331
 332                 printk(KERN_INFO "netconsole: network logging started\n");
 333
 334         } else {        /* 0 */
 335                 netpoll_cleanup(&nt->np);
 336         }
 337
 338         nt->enabled = enabled;
 339
 340         return strnlen(buf, count);
 341 }
 342
 343 static ssize_t store_dev_name(struct netconsole_target *nt,
 344                               const char *buf,
 345                               size_t count)
 346 {
 347         size_t len;
 348
 349         if (nt->enabled) {
 350                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 351                                 "disable to update parameters\n",
 352                                 config_item_name(&nt->item));
 353                 return -EINVAL;
 354         }
 355
 356         strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
 357
 358         /* Get rid of possible trailing newline from echo(1) */
 359         len = strnlen(nt->np.dev_name, IFNAMSIZ);
 360         if (nt->np.dev_name[len - 1] == '\n')
 361                 nt->np.dev_name[len - 1] = '\0';
 362
 363         return strnlen(buf, count);
 364 }
 365
 366 static ssize_t store_local_port(struct netconsole_target *nt,
 367                                 const char *buf,
 368                                 size_t count)
 369 {
 370         int rv;
 371
 372         if (nt->enabled) {
 373                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 374                                 "disable to update parameters\n",
 375                                 config_item_name(&nt->item));
 376                 return -EINVAL;
 377         }
 378
 379         rv = kstrtou16(buf, 10, &nt->np.local_port);
 380         if (rv < 0)
 381                 return rv;
 382         return strnlen(buf, count);
 383 }
 384
 385 static ssize_t store_remote_port(struct netconsole_target *nt,
 386                                  const char *buf,
 387                                  size_t count)
 388 {
 389         int rv;
 390
 391         if (nt->enabled) {
 392                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 393                                 "disable to update parameters\n",
 394                                 config_item_name(&nt->item));
 395                 return -EINVAL;
 396         }
 397
 398         rv = kstrtou16(buf, 10, &nt->np.remote_port);
 399         if (rv < 0)
 400                 return rv;
 401         return strnlen(buf, count);
 402 }
 403
 404 static ssize_t store_local_ip(struct netconsole_target *nt,
 405                               const char *buf,
 406                               size_t count)
 407 {
 408         if (nt->enabled) {
 409                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 410                                 "disable to update parameters\n",
 411                                 config_item_name(&nt->item));
 412                 return -EINVAL;
 413         }
 414
 415         if (!strnchr(buf, count, ':'))
 416                 nt->np.local_ip.ip = in_aton(buf);
 417
 418         return strnlen(buf, count);
 419 }
 420
 421 static ssize_t store_remote_ip(struct netconsole_target *nt,
 422                                const char *buf,
 423                                size_t count)
 424 {
 425         if (nt->enabled) {
 426                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 427                                 "disable to update parameters\n",
 428                                 config_item_name(&nt->item));
 429                 return -EINVAL;
 430         }
 431
 432         if (!strnchr(buf, count, ':'))
 433                 nt->np.remote_ip.ip = in_aton(buf);
 434
 435         return strnlen(buf, count);
 436 }
 437
 438 static ssize_t store_remote_mac(struct netconsole_target *nt,
 439                                 const char *buf,
 440                                 size_t count)
 441 {
 442         u8 remote_mac[ETH_ALEN];
 443
 444         if (nt->enabled) {
 445                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
 446                                 "disable to update parameters\n",
 447                                 config_item_name(&nt->item));
 448                 return -EINVAL;
 449         }
 450
 451         if (!mac_pton(buf, remote_mac))
 452                 return -EINVAL;
 453         if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
 454                 return -EINVAL;
 455         memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
 456
 457         return strnlen(buf, count);
 458 }
 459
 460 /*
 461  * Attribute definitions for netconsole_target.
 462  */
 463
 464 #define NETCONSOLE_TARGET_ATTR_RO(_name)                                \
 465 static struct netconsole_target_attr netconsole_target_##_name =        \
 466         __CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
 467
 468 #define NETCONSOLE_TARGET_ATTR_RW(_name)                                \
 469 static struct netconsole_target_attr netconsole_target_##_name =        \
 470         __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
 471
 472 NETCONSOLE_TARGET_ATTR_RW(enabled);
 473 NETCONSOLE_TARGET_ATTR_RW(dev_name);
 474 NETCONSOLE_TARGET_ATTR_RW(local_port);
 475 NETCONSOLE_TARGET_ATTR_RW(remote_port);
 476 NETCONSOLE_TARGET_ATTR_RW(local_ip);
 477 NETCONSOLE_TARGET_ATTR_RW(remote_ip);
 478 NETCONSOLE_TARGET_ATTR_RO(local_mac);
 479 NETCONSOLE_TARGET_ATTR_RW(remote_mac);
 480
 481 static struct configfs_attribute *netconsole_target_attrs[] = {
 482         &netconsole_target_enabled.attr,
 483         &netconsole_target_dev_name.attr,
 484         &netconsole_target_local_port.attr,
 485         &netconsole_target_remote_port.attr,
 486         &netconsole_target_local_ip.attr,
 487         &netconsole_target_remote_ip.attr,
 488         &netconsole_target_local_mac.attr,
 489         &netconsole_target_remote_mac.attr,
 490         NULL,
 491 };
 492
 493 /*
 494  * Item operations and type for netconsole_target.
 495  */
 496
 497 static void netconsole_target_release(struct config_item *item)
 498 {
 499         kfree(to_target(item));
 500 }
 501
 502 static ssize_t netconsole_target_attr_show(struct config_item *item,
 503                                            struct configfs_attribute *attr,
 504                                            char *buf)
 505 {
 506         ssize_t ret = -EINVAL;
 507         struct netconsole_target *nt = to_target(item);
 508         struct netconsole_target_attr *na =
 509                 container_of(attr, struct netconsole_target_attr, attr);
 510
 511         if (na->show)
 512                 ret = na->show(nt, buf);
 513
 514         return ret;
 515 }
 516
 517 static ssize_t netconsole_target_attr_store(struct config_item *item,
 518                                             struct configfs_attribute *attr,
 519                                             const char *buf,
 520                                             size_t count)
 521 {
 522         ssize_t ret = -EINVAL;
 523         struct netconsole_target *nt = to_target(item);
 524         struct netconsole_target_attr *na =
 525                 container_of(attr, struct netconsole_target_attr, attr);
 526
 527         if (na->store)
 528                 ret = na->store(nt, buf, count);
 529
 530         return ret;
 531 }
 532
 533 static struct configfs_item_operations netconsole_target_item_ops = {
 534         .release                = netconsole_target_release,
 535         .show_attribute         = netconsole_target_attr_show,
 536         .store_attribute        = netconsole_target_attr_store,
 537 };
 538
 539 static struct config_item_type netconsole_target_type = {
 540         .ct_attrs               = netconsole_target_attrs,
 541         .ct_item_ops            = &netconsole_target_item_ops,
 542         .ct_owner               = THIS_MODULE,
 543 };
 544
 545 /*
 546  * Group operations and type for netconsole_subsys.
 547  */
 548
 549 static struct config_item *make_netconsole_target(struct config_group *group,
 550                                                   const char *name)
 551 {
 552         unsigned long flags;
 553         struct netconsole_target *nt;
 554
 555         /*
 556          * Allocate and initialize with defaults.
 557          * Target is disabled at creation (enabled == 0).
 558          */
 559         nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 560         if (!nt)
 561                 return ERR_PTR(-ENOMEM);
 562
 563         nt->np.name = "netconsole";
 564         strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
 565         nt->np.local_port = 6665;
 566         nt->np.remote_port = 6666;
 567         memset(nt->np.remote_mac, 0xff, ETH_ALEN);
 568
 569         /* Initialize the config_item member */
 570         config_item_init_type_name(&nt->item, name, &netconsole_target_type);
 571
 572         /* Adding, but it is disabled */
 573         spin_lock_irqsave(&target_list_lock, flags);
 574         list_add(&nt->list, &target_list);
 575         spin_unlock_irqrestore(&target_list_lock, flags);
 576
 577         return &nt->item;
 578 }
 579
 580 static void drop_netconsole_target(struct config_group *group,
 581                                    struct config_item *item)
 582 {
 583         unsigned long flags;
 584         struct netconsole_target *nt = to_target(item);
 585
 586         spin_lock_irqsave(&target_list_lock, flags);
 587         list_del(&nt->list);
 588         spin_unlock_irqrestore(&target_list_lock, flags);
 589
 590         /*
 591          * The target may have never been enabled, or was manually disabled
 592          * before being removed so netpoll may have already been cleaned up.
 593          */
 594         if (nt->enabled)
 595                 netpoll_cleanup(&nt->np);
 596
 597         config_item_put(&nt->item);
 598 }
 599
 600 static struct configfs_group_operations netconsole_subsys_group_ops = {
 601         .make_item      = make_netconsole_target,
 602         .drop_item      = drop_netconsole_target,
 603 };
 604
 605 static struct config_item_type netconsole_subsys_type = {
 606         .ct_group_ops   = &netconsole_subsys_group_ops,
 607         .ct_owner       = THIS_MODULE,
 608 };
 609
 610 /* The netconsole configfs subsystem */
 611 static struct configfs_subsystem netconsole_subsys = {
 612         .su_group       = {
 613                 .cg_item        = {
 614                         .ci_namebuf     = "netconsole",
 615                         .ci_type        = &netconsole_subsys_type,
 616                 },
 617         },
 618 };
 619
 620 #endif  /* CONFIG_NETCONSOLE_DYNAMIC */
 621
 622 /* Handle network interface device notifications */
 623 static int netconsole_netdev_event(struct notifier_block *this,
 624                                    unsigned long event,
 625                                    void *ptr)
 626 {
 627         unsigned long flags;
 628         struct netconsole_target *nt;
 629         struct net_device *dev = ptr;
 630         bool stopped = false;
 631
 632         if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
 633               event == NETDEV_RELEASE || event == NETDEV_JOIN))
 634                 goto done;
 635
 636         spin_lock_irqsave(&target_list_lock, flags);
 637         list_for_each_entry(nt, &target_list, list) {
 638                 netconsole_target_get(nt);
 639                 if (nt->np.dev == dev) {
 640                         switch (event) {
 641                         case NETDEV_CHANGENAME:
 642                                 strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
 643                                 break;
 644                         case NETDEV_RELEASE:
 645                         case NETDEV_JOIN:
 646                         case NETDEV_UNREGISTER:
 647                                 /*
 648                                  * rtnl_lock already held
 649                                  */
 650                                 if (nt->np.dev) {
 651                                         __netpoll_cleanup(&nt->np);
 652                                         dev_put(nt->np.dev);
 653                                         nt->np.dev = NULL;
 654                                 }
 655                                 nt->enabled = 0;
 656                                 stopped = true;
 657                                 break;
 658                         }
 659                 }
 660                 netconsole_target_put(nt);
 661         }
 662         spin_unlock_irqrestore(&target_list_lock, flags);
 663         if (stopped) {
 664                 printk(KERN_INFO "netconsole: network logging stopped on "
 665                        "interface %s as it ", dev->name);
 666                 switch (event) {
 667                 case NETDEV_UNREGISTER:
 668                         printk(KERN_CONT "unregistered\n");
 669                         break;
 670                 case NETDEV_RELEASE:
 671                         printk(KERN_CONT "released slaves\n");
 672                         break;
 673                 case NETDEV_JOIN:
 674                         printk(KERN_CONT "is joining a master device\n");
 675                         break;
 676                 }
 677         }
 678
 679 done:
 680         return NOTIFY_DONE;
 681 }
 682
 683 static struct notifier_block netconsole_netdev_notifier = {
 684         .notifier_call  = netconsole_netdev_event,
 685 };
 686
 687 static void write_msg(struct console *con, const char *msg, unsigned int len)
 688 {
 689         int frag, left;
 690         unsigned long flags;
 691         struct netconsole_target *nt;
 692         const char *tmp;
 693
 694         if (oops_only && !oops_in_progress)
 695                 return;
 696         /* Avoid taking lock and disabling interrupts unnecessarily */
 697         if (list_empty(&target_list))
 698                 return;
 699
 700         spin_lock_irqsave(&target_list_lock, flags);
 701         list_for_each_entry(nt, &target_list, list) {
 702                 netconsole_target_get(nt);
 703                 if (nt->enabled && netif_running(nt->np.dev)) {
 704                         /*
 705                          * We nest this inside the for-each-target loop above
 706                          * so that we're able to get as much logging out to
 707                          * at least one target if we die inside here, instead
 708                          * of unnecessarily keeping all targets in lock-step.
 709                          */
 710                         tmp = msg;
 711                         for (left = len; left;) {
 712                                 frag = min(left, MAX_PRINT_CHUNK);
 713                                 netpoll_send_udp(&nt->np, tmp, frag);
 714                                 tmp += frag;
 715                                 left -= frag;
 716                         }
 717                 }
 718                 netconsole_target_put(nt);
 719         }
 720         spin_unlock_irqrestore(&target_list_lock, flags);
 721 }
 722
 723 static struct console netconsole = {
 724         .name   = "netcon",
 725         .flags  = CON_ENABLED,
 726         .write  = write_msg,
 727 };
 728
 729 static int __init init_netconsole(void)
 730 {
 731         int err;
 732         struct netconsole_target *nt, *tmp;
 733         unsigned long flags;
 734         char *target_config;
 735         char *input = config;
 736
 737         if (strnlen(input, MAX_PARAM_LENGTH)) {
 738                 while ((target_config = strsep(&input, ";"))) {
 739                         nt = alloc_param_target(target_config);
 740                         if (IS_ERR(nt)) {
 741                                 err = PTR_ERR(nt);
 742                                 goto fail;
 743                         }
 744                         /* Dump existing printks when we register */
 745                         netconsole.flags |= CON_PRINTBUFFER;
 746
 747                         spin_lock_irqsave(&target_list_lock, flags);
 748                         list_add(&nt->list, &target_list);
 749                         spin_unlock_irqrestore(&target_list_lock, flags);
 750                 }
 751         }
 752
 753         err = register_netdevice_notifier(&netconsole_netdev_notifier);
 754         if (err)
 755                 goto fail;
 756
 757         err = dynamic_netconsole_init();
 758         if (err)
 759                 goto undonotifier;
 760
 761         register_console(&netconsole);
 762         printk(KERN_INFO "netconsole: network logging started\n");
 763
 764         return err;
 765
 766 undonotifier:
 767         unregister_netdevice_notifier(&netconsole_netdev_notifier);
 768
 769 fail:
 770         printk(KERN_ERR "netconsole: cleaning up\n");
 771
 772         /*
 773          * Remove all targets and destroy them (only targets created
 774          * from the boot/module option exist here). Skipping the list
 775          * lock is safe here, and netpoll_cleanup() will sleep.
 776          */
 777         list_for_each_entry_safe(nt, tmp, &target_list, list) {
 778                 list_del(&nt->list);
 779                 free_param_target(nt);
 780         }
 781
 782         return err;
 783 }
 784
 785 static void __exit cleanup_netconsole(void)
 786 {
 787         struct netconsole_target *nt, *tmp;
 788
 789         unregister_console(&netconsole);
 790         dynamic_netconsole_exit();
 791         unregister_netdevice_notifier(&netconsole_netdev_notifier);
 792
 793         /*
 794          * Targets created via configfs pin references on our module
 795          * and would first be rmdir(2)'ed from userspace. We reach
 796          * here only when they are already destroyed, and only those
 797          * created from the boot/module option are left, so remove and
 798          * destroy them. Skipping the list lock is safe here, and
 799          * netpoll_cleanup() will sleep.
 800          */
 801         list_for_each_entry_safe(nt, tmp, &target_list, list) {
 802                 list_del(&nt->list);
 803                 free_param_target(nt);
 804         }
 805 }
 806
 807 /*
 808  * Use late_initcall to ensure netconsole is
 809  * initialized after network device driver if built-in.
 810  *
 811  * late_initcall() and module_init() are identical if built as module.
 812  */
 813 late_initcall(init_netconsole);
 814 module_exit(cleanup_netconsole);