netconsole.c revision f89ab8619e5320cc9c2576f5f8dcbaf6c0ba3950 
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/console.h>
41#include <linux/moduleparam.h>
42#include <linux/string.h>
43#include <linux/netpoll.h>
44#include <linux/inet.h>
45#include <linux/configfs.h>
46
47MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
48MODULE_DESCRIPTION("Console driver for network interfaces");
49MODULE_LICENSE("GPL");
50
51#define MAX_PARAM_LENGTH	256
52#define MAX_PRINT_CHUNK		1000
53
54static char config[MAX_PARAM_LENGTH];
55module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
56MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]\n");
57
58#ifndef	MODULE
59static int __init option_setup(char *opt)
60{
61	strlcpy(config, opt, MAX_PARAM_LENGTH);
62	return 1;
63}
64__setup("netconsole=", option_setup);
65#endif	/* MODULE */
66
67/* Linked list of all configured targets */
68static LIST_HEAD(target_list);
69
70/* This needs to be a spinlock because write_msg() cannot sleep */
71static DEFINE_SPINLOCK(target_list_lock);
72
73/**
74 * struct netconsole_target - Represents a configured netconsole target.
75 * @list:	Links this target into the target_list.
76 * @item:	Links us into the configfs subsystem hierarchy.
77 * @enabled:	On / off knob to enable / disable target.
78 *		Visible from userspace (read-write).
79 *		We maintain a strict 1:1 correspondence between this and
80 *		whether the corresponding netpoll is active or inactive.
81 *		Also, other parameters of a target may be modified at
82 *		runtime only when it is disabled (enabled == 0).
83 * @np:		The netpoll structure for this target.
84 *		Contains the other userspace visible parameters:
85 *		dev_name	(read-write)
86 *		local_port	(read-write)
87 *		remote_port	(read-write)
88 *		local_ip	(read-write)
89 *		remote_ip	(read-write)
90 *		local_mac	(read-only)
91 *		remote_mac	(read-write)
92 */
93struct netconsole_target {
94	struct list_head	list;
95#ifdef	CONFIG_NETCONSOLE_DYNAMIC
96	struct config_item	item;
97#endif
98	int			enabled;
99	struct netpoll		np;
100};
101
102#ifdef	CONFIG_NETCONSOLE_DYNAMIC
103
104static struct configfs_subsystem netconsole_subsys;
105
106static int __init dynamic_netconsole_init(void)
107{
108	config_group_init(&netconsole_subsys.su_group);
109	mutex_init(&netconsole_subsys.su_mutex);
110	return configfs_register_subsystem(&netconsole_subsys);
111}
112
113static void __exit dynamic_netconsole_exit(void)
114{
115	configfs_unregister_subsystem(&netconsole_subsys);
116}
117
118/*
119 * Targets that were created by parsing the boot/module option string
120 * do not exist in the configfs hierarchy (and have NULL names) and will
121 * never go away, so make these a no-op for them.
122 */
123static void netconsole_target_get(struct netconsole_target *nt)
124{
125	if (config_item_name(&nt->item))
126		config_item_get(&nt->item);
127}
128
129static void netconsole_target_put(struct netconsole_target *nt)
130{
131	if (config_item_name(&nt->item))
132		config_item_put(&nt->item);
133}
134
135#else	/* !CONFIG_NETCONSOLE_DYNAMIC */
136
137static int __init dynamic_netconsole_init(void)
138{
139	return 0;
140}
141
142static void __exit dynamic_netconsole_exit(void)
143{
144}
145
146/*
147 * No danger of targets going away from under us when dynamic
148 * reconfigurability is off.
149 */
150static void netconsole_target_get(struct netconsole_target *nt)
151{
152}
153
154static void netconsole_target_put(struct netconsole_target *nt)
155{
156}
157
158#endif	/* CONFIG_NETCONSOLE_DYNAMIC */
159
160/* Allocate new target (from boot/module param) and setup netpoll for it */
161static struct netconsole_target *alloc_param_target(char *target_config)
162{
163	int err = -ENOMEM;
164	struct netconsole_target *nt;
165
166	/*
167	 * Allocate and initialize with defaults.
168	 * Note that these targets get their config_item fields zeroed-out.
169	 */
170	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
171	if (!nt) {
172		printk(KERN_ERR "netconsole: failed to allocate memory\n");
173		goto fail;
174	}
175
176	nt->np.name = "netconsole";
177	strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
178	nt->np.local_port = 6665;
179	nt->np.remote_port = 6666;
180	memset(nt->np.remote_mac, 0xff, ETH_ALEN);
181
182	/* Parse parameters and setup netpoll */
183	err = netpoll_parse_options(&nt->np, target_config);
184	if (err)
185		goto fail;
186
187	err = netpoll_setup(&nt->np);
188	if (err)
189		goto fail;
190
191	nt->enabled = 1;
192
193	return nt;
194
195fail:
196	kfree(nt);
197	return ERR_PTR(err);
198}
199
200/* Cleanup netpoll for given target (from boot/module param) and free it */
201static void free_param_target(struct netconsole_target *nt)
202{
203	netpoll_cleanup(&nt->np);
204	kfree(nt);
205}
206
207#ifdef	CONFIG_NETCONSOLE_DYNAMIC
208
209/*
210 * Our subsystem hierarchy is:
211 *
212 * /sys/kernel/config/netconsole/
213 *				|
214 *				<target>/
215 *				|	enabled
216 *				|	dev_name
217 *				|	local_port
218 *				|	remote_port
219 *				|	local_ip
220 *				|	remote_ip
221 *				|	local_mac
222 *				|	remote_mac
223 *				|
224 *				<target>/...
225 */
226
227struct netconsole_target_attr {
228	struct configfs_attribute	attr;
229	ssize_t				(*show)(struct netconsole_target *nt,
230						char *buf);
231	ssize_t				(*store)(struct netconsole_target *nt,
232						 const char *buf,
233						 size_t count);
234};
235
236static struct netconsole_target *to_target(struct config_item *item)
237{
238	return item ?
239		container_of(item, struct netconsole_target, item) :
240		NULL;
241}
242
243/*
244 * Wrapper over simple_strtol (base 10) with sanity and range checking.
245 * We return (signed) long only because we may want to return errors.
246 * Do not use this to convert numbers that are allowed to be negative.
247 */
248static long strtol10_check_range(const char *cp, long min, long max)
249{
250	long ret;
251	char *p = (char *) cp;
252
253	WARN_ON(min < 0);
254	WARN_ON(max < min);
255
256	ret = simple_strtol(p, &p, 10);
257
258	if (*p && (*p != '\n')) {
259		printk(KERN_ERR "netconsole: invalid input\n");
260		return -EINVAL;
261	}
262	if ((ret < min) || (ret > max)) {
263		printk(KERN_ERR "netconsole: input %ld must be between "
264				"%ld and %ld\n", ret, min, max);
265		return -EINVAL;
266	}
267
268	return ret;
269}
270
271/*
272 * Attribute operations for netconsole_target.
273 */
274
275static ssize_t show_enabled(struct netconsole_target *nt, char *buf)
276{
277	return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled);
278}
279
280static ssize_t show_dev_name(struct netconsole_target *nt, char *buf)
281{
282	return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name);
283}
284
285static ssize_t show_local_port(struct netconsole_target *nt, char *buf)
286{
287	return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.local_port);
288}
289
290static ssize_t show_remote_port(struct netconsole_target *nt, char *buf)
291{
292	return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.remote_port);
293}
294
295static ssize_t show_local_ip(struct netconsole_target *nt, char *buf)
296{
297	return snprintf(buf, PAGE_SIZE, "%d.%d.%d.%d\n",
298			HIPQUAD(nt->np.local_ip));
299}
300
301static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
302{
303	return snprintf(buf, PAGE_SIZE, "%d.%d.%d.%d\n",
304			HIPQUAD(nt->np.remote_ip));
305}
306
307static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
308{
309	struct net_device *dev = nt->np.dev;
310
311	DECLARE_MAC_BUF(mac);
312	return snprintf(buf, PAGE_SIZE, "%s\n", dev ?
313			print_mac(mac, dev->dev_addr) : "ff:ff:ff:ff:ff:ff");
314}
315
316static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
317{
318	DECLARE_MAC_BUF(mac);
319	return snprintf(buf, PAGE_SIZE, "%s\n",
320			print_mac(mac, nt->np.remote_mac));
321}
322
323/*
324 * This one is special -- targets created through the configfs interface
325 * are not enabled (and the corresponding netpoll activated) by default.
326 * The user is expected to set the desired parameters first (which
327 * would enable him to dynamically add new netpoll targets for new
328 * network interfaces as and when they come up).
329 */
330static ssize_t store_enabled(struct netconsole_target *nt,
331			     const char *buf,
332			     size_t count)
333{
334	int err;
335	long enabled;
336
337	enabled = strtol10_check_range(buf, 0, 1);
338	if (enabled < 0)
339		return enabled;
340
341	if (enabled) {	/* 1 */
342
343		/*
344		 * Skip netpoll_parse_options() -- all the attributes are
345		 * already configured via configfs. Just print them out.
346		 */
347		netpoll_print_options(&nt->np);
348
349		err = netpoll_setup(&nt->np);
350		if (err)
351			return err;
352
353		printk(KERN_INFO "netconsole: network logging started\n");
354
355	} else {	/* 0 */
356		netpoll_cleanup(&nt->np);
357	}
358
359	nt->enabled = enabled;
360
361	return strnlen(buf, count);
362}
363
364static ssize_t store_dev_name(struct netconsole_target *nt,
365			      const char *buf,
366			      size_t count)
367{
368	size_t len;
369
370	if (nt->enabled) {
371		printk(KERN_ERR "netconsole: target (%s) is enabled, "
372				"disable to update parameters\n",
373				config_item_name(&nt->item));
374		return -EINVAL;
375	}
376
377	strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
378
379	/* Get rid of possible trailing newline from echo(1) */
380	len = strnlen(nt->np.dev_name, IFNAMSIZ);
381	if (nt->np.dev_name[len - 1] == '\n')
382		nt->np.dev_name[len - 1] = '\0';
383
384	return strnlen(buf, count);
385}
386
387static ssize_t store_local_port(struct netconsole_target *nt,
388				const char *buf,
389				size_t count)
390{
391	long local_port;
392#define __U16_MAX	((__u16) ~0U)
393
394	if (nt->enabled) {
395		printk(KERN_ERR "netconsole: target (%s) is enabled, "
396				"disable to update parameters\n",
397				config_item_name(&nt->item));
398		return -EINVAL;
399	}
400
401	local_port = strtol10_check_range(buf, 0, __U16_MAX);
402	if (local_port < 0)
403		return local_port;
404
405	nt->np.local_port = local_port;
406
407	return strnlen(buf, count);
408}
409
410static ssize_t store_remote_port(struct netconsole_target *nt,
411				 const char *buf,
412				 size_t count)
413{
414	long remote_port;
415#define __U16_MAX	((__u16) ~0U)
416
417	if (nt->enabled) {
418		printk(KERN_ERR "netconsole: target (%s) is enabled, "
419				"disable to update parameters\n",
420				config_item_name(&nt->item));
421		return -EINVAL;
422	}
423
424	remote_port = strtol10_check_range(buf, 0, __U16_MAX);
425	if (remote_port < 0)
426		return remote_port;
427
428	nt->np.remote_port = remote_port;
429
430	return strnlen(buf, count);
431}
432
433static ssize_t store_local_ip(struct netconsole_target *nt,
434			      const char *buf,
435			      size_t count)
436{
437	if (nt->enabled) {
438		printk(KERN_ERR "netconsole: target (%s) is enabled, "
439				"disable to update parameters\n",
440				config_item_name(&nt->item));
441		return -EINVAL;
442	}
443
444	nt->np.local_ip = ntohl(in_aton(buf));
445
446	return strnlen(buf, count);
447}
448
449static ssize_t store_remote_ip(struct netconsole_target *nt,
450			       const char *buf,
451			       size_t count)
452{
453	if (nt->enabled) {
454		printk(KERN_ERR "netconsole: target (%s) is enabled, "
455				"disable to update parameters\n",
456				config_item_name(&nt->item));
457		return -EINVAL;
458	}
459
460	nt->np.remote_ip = ntohl(in_aton(buf));
461
462	return strnlen(buf, count);
463}
464
465static ssize_t store_remote_mac(struct netconsole_target *nt,
466				const char *buf,
467				size_t count)
468{
469	u8 remote_mac[ETH_ALEN];
470	char *p = (char *) buf;
471	int i;
472
473	if (nt->enabled) {
474		printk(KERN_ERR "netconsole: target (%s) is enabled, "
475				"disable to update parameters\n",
476				config_item_name(&nt->item));
477		return -EINVAL;
478	}
479
480	for (i = 0; i < ETH_ALEN - 1; i++) {
481		remote_mac[i] = simple_strtoul(p, &p, 16);
482		if (*p != ':')
483			goto invalid;
484		p++;
485	}
486	remote_mac[ETH_ALEN - 1] = simple_strtoul(p, &p, 16);
487	if (*p && (*p != '\n'))
488		goto invalid;
489
490	memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
491
492	return strnlen(buf, count);
493
494invalid:
495	printk(KERN_ERR "netconsole: invalid input\n");
496	return -EINVAL;
497}
498
499/*
500 * Attribute definitions for netconsole_target.
501 */
502
503#define NETCONSOLE_TARGET_ATTR_RO(_name)				\
504static struct netconsole_target_attr netconsole_target_##_name =	\
505	__CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
506
507#define NETCONSOLE_TARGET_ATTR_RW(_name)				\
508static struct netconsole_target_attr netconsole_target_##_name =	\
509	__CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
510
511NETCONSOLE_TARGET_ATTR_RW(enabled);
512NETCONSOLE_TARGET_ATTR_RW(dev_name);
513NETCONSOLE_TARGET_ATTR_RW(local_port);
514NETCONSOLE_TARGET_ATTR_RW(remote_port);
515NETCONSOLE_TARGET_ATTR_RW(local_ip);
516NETCONSOLE_TARGET_ATTR_RW(remote_ip);
517NETCONSOLE_TARGET_ATTR_RO(local_mac);
518NETCONSOLE_TARGET_ATTR_RW(remote_mac);
519
520static struct configfs_attribute *netconsole_target_attrs[] = {
521	&netconsole_target_enabled.attr,
522	&netconsole_target_dev_name.attr,
523	&netconsole_target_local_port.attr,
524	&netconsole_target_remote_port.attr,
525	&netconsole_target_local_ip.attr,
526	&netconsole_target_remote_ip.attr,
527	&netconsole_target_local_mac.attr,
528	&netconsole_target_remote_mac.attr,
529	NULL,
530};
531
532/*
533 * Item operations and type for netconsole_target.
534 */
535
536static void netconsole_target_release(struct config_item *item)
537{
538	kfree(to_target(item));
539}
540
541static ssize_t netconsole_target_attr_show(struct config_item *item,
542					   struct configfs_attribute *attr,
543					   char *buf)
544{
545	ssize_t ret = -EINVAL;
546	struct netconsole_target *nt = to_target(item);
547	struct netconsole_target_attr *na =
548		container_of(attr, struct netconsole_target_attr, attr);
549
550	if (na->show)
551		ret = na->show(nt, buf);
552
553	return ret;
554}
555
556static ssize_t netconsole_target_attr_store(struct config_item *item,
557					    struct configfs_attribute *attr,
558					    const char *buf,
559					    size_t count)
560{
561	ssize_t ret = -EINVAL;
562	struct netconsole_target *nt = to_target(item);
563	struct netconsole_target_attr *na =
564		container_of(attr, struct netconsole_target_attr, attr);
565
566	if (na->store)
567		ret = na->store(nt, buf, count);
568
569	return ret;
570}
571
572static struct configfs_item_operations netconsole_target_item_ops = {
573	.release		= netconsole_target_release,
574	.show_attribute		= netconsole_target_attr_show,
575	.store_attribute	= netconsole_target_attr_store,
576};
577
578static struct config_item_type netconsole_target_type = {
579	.ct_attrs		= netconsole_target_attrs,
580	.ct_item_ops		= &netconsole_target_item_ops,
581	.ct_owner		= THIS_MODULE,
582};
583
584/*
585 * Group operations and type for netconsole_subsys.
586 */
587
588static struct config_item *make_netconsole_target(struct config_group *group,
589						  const char *name)
590{
591	unsigned long flags;
592	struct netconsole_target *nt;
593
594	/*
595	 * Allocate and initialize with defaults.
596	 * Target is disabled at creation (enabled == 0).
597	 */
598	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
599	if (!nt) {
600		printk(KERN_ERR "netconsole: failed to allocate memory\n");
601		return NULL;
602	}
603
604	nt->np.name = "netconsole";
605	strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
606	nt->np.local_port = 6665;
607	nt->np.remote_port = 6666;
608	memset(nt->np.remote_mac, 0xff, ETH_ALEN);
609
610	/* Initialize the config_item member */
611	config_item_init_type_name(&nt->item, name, &netconsole_target_type);
612
613	/* Adding, but it is disabled */
614	spin_lock_irqsave(&target_list_lock, flags);
615	list_add(&nt->list, &target_list);
616	spin_unlock_irqrestore(&target_list_lock, flags);
617
618	return &nt->item;
619}
620
621static void drop_netconsole_target(struct config_group *group,
622				   struct config_item *item)
623{
624	unsigned long flags;
625	struct netconsole_target *nt = to_target(item);
626
627	spin_lock_irqsave(&target_list_lock, flags);
628	list_del(&nt->list);
629	spin_unlock_irqrestore(&target_list_lock, flags);
630
631	/*
632	 * The target may have never been enabled, or was manually disabled
633	 * before being removed so netpoll may have already been cleaned up.
634	 */
635	if (nt->enabled)
636		netpoll_cleanup(&nt->np);
637
638	config_item_put(&nt->item);
639}
640
641static struct configfs_group_operations netconsole_subsys_group_ops = {
642	.make_item	= make_netconsole_target,
643	.drop_item	= drop_netconsole_target,
644};
645
646static struct config_item_type netconsole_subsys_type = {
647	.ct_group_ops	= &netconsole_subsys_group_ops,
648	.ct_owner	= THIS_MODULE,
649};
650
651/* The netconsole configfs subsystem */
652static struct configfs_subsystem netconsole_subsys = {
653	.su_group	= {
654		.cg_item	= {
655			.ci_namebuf	= "netconsole",
656			.ci_type	= &netconsole_subsys_type,
657		},
658	},
659};
660
661#endif	/* CONFIG_NETCONSOLE_DYNAMIC */
662
663/* Handle network interface device notifications */
664static int netconsole_netdev_event(struct notifier_block *this,
665				   unsigned long event,
666				   void *ptr)
667{
668	unsigned long flags;
669	struct netconsole_target *nt;
670	struct net_device *dev = ptr;
671
672	if (!(event == NETDEV_CHANGENAME))
673		goto done;
674
675	spin_lock_irqsave(&target_list_lock, flags);
676	list_for_each_entry(nt, &target_list, list) {
677		netconsole_target_get(nt);
678		if (nt->np.dev == dev) {
679			switch (event) {
680			case NETDEV_CHANGENAME:
681				strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
682				break;
683			}
684		}
685		netconsole_target_put(nt);
686	}
687	spin_unlock_irqrestore(&target_list_lock, flags);
688
689done:
690	return NOTIFY_DONE;
691}
692
693static struct notifier_block netconsole_netdev_notifier = {
694	.notifier_call  = netconsole_netdev_event,
695};
696
697static void write_msg(struct console *con, const char *msg, unsigned int len)
698{
699	int frag, left;
700	unsigned long flags;
701	struct netconsole_target *nt;
702	const char *tmp;
703
704	/* Avoid taking lock and disabling interrupts unnecessarily */
705	if (list_empty(&target_list))
706		return;
707
708	spin_lock_irqsave(&target_list_lock, flags);
709	list_for_each_entry(nt, &target_list, list) {
710		netconsole_target_get(nt);
711		if (nt->enabled && netif_running(nt->np.dev)) {
712			/*
713			 * We nest this inside the for-each-target loop above
714			 * so that we're able to get as much logging out to
715			 * at least one target if we die inside here, instead
716			 * of unnecessarily keeping all targets in lock-step.
717			 */
718			tmp = msg;
719			for (left = len; left;) {
720				frag = min(left, MAX_PRINT_CHUNK);
721				netpoll_send_udp(&nt->np, tmp, frag);
722				tmp += frag;
723				left -= frag;
724			}
725		}
726		netconsole_target_put(nt);
727	}
728	spin_unlock_irqrestore(&target_list_lock, flags);
729}
730
731static struct console netconsole = {
732	.name	= "netcon",
733	.flags	= CON_ENABLED,
734	.write	= write_msg,
735};
736
737static int __init init_netconsole(void)
738{
739	int err;
740	struct netconsole_target *nt, *tmp;
741	unsigned long flags;
742	char *target_config;
743	char *input = config;
744
745	if (strnlen(input, MAX_PARAM_LENGTH)) {
746		while ((target_config = strsep(&input, ";"))) {
747			nt = alloc_param_target(target_config);
748			if (IS_ERR(nt)) {
749				err = PTR_ERR(nt);
750				goto fail;
751			}
752			/* Dump existing printks when we register */
753			netconsole.flags |= CON_PRINTBUFFER;
754
755			spin_lock_irqsave(&target_list_lock, flags);
756			list_add(&nt->list, &target_list);
757			spin_unlock_irqrestore(&target_list_lock, flags);
758		}
759	}
760
761	err = register_netdevice_notifier(&netconsole_netdev_notifier);
762	if (err)
763		goto fail;
764
765	err = dynamic_netconsole_init();
766	if (err)
767		goto undonotifier;
768
769	register_console(&netconsole);
770	printk(KERN_INFO "netconsole: network logging started\n");
771
772	return err;
773
774undonotifier:
775	unregister_netdevice_notifier(&netconsole_netdev_notifier);
776
777fail:
778	printk(KERN_ERR "netconsole: cleaning up\n");
779
780	/*
781	 * Remove all targets and destroy them (only targets created
782	 * from the boot/module option exist here). Skipping the list
783	 * lock is safe here, and netpoll_cleanup() will sleep.
784	 */
785	list_for_each_entry_safe(nt, tmp, &target_list, list) {
786		list_del(&nt->list);
787		free_param_target(nt);
788	}
789
790	return err;
791}
792
793static void __exit cleanup_netconsole(void)
794{
795	struct netconsole_target *nt, *tmp;
796
797	unregister_console(&netconsole);
798	dynamic_netconsole_exit();
799	unregister_netdevice_notifier(&netconsole_netdev_notifier);
800
801	/*
802	 * Targets created via configfs pin references on our module
803	 * and would first be rmdir(2)'ed from userspace. We reach
804	 * here only when they are already destroyed, and only those
805	 * created from the boot/module option are left, so remove and
806	 * destroy them. Skipping the list lock is safe here, and
807	 * 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
815module_init(init_netconsole);
816module_exit(cleanup_netconsole);
817