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