Root/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/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]");
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, "%pI4\n", &nt->np.local_ip);
298}
299
300static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
301{
302    return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
303}
304
305static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
306{
307    struct net_device *dev = nt->np.dev;
308    static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
309
310    return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
311}
312
313static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
314{
315    return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac);
316}
317
318/*
319 * This one is special -- targets created through the configfs interface
320 * are not enabled (and the corresponding netpoll activated) by default.
321 * The user is expected to set the desired parameters first (which
322 * would enable him to dynamically add new netpoll targets for new
323 * network interfaces as and when they come up).
324 */
325static ssize_t store_enabled(struct netconsole_target *nt,
326                 const char *buf,
327                 size_t count)
328{
329    int err;
330    long enabled;
331
332    enabled = strtol10_check_range(buf, 0, 1);
333    if (enabled < 0)
334        return enabled;
335
336    if (enabled) { /* 1 */
337
338        /*
339         * Skip netpoll_parse_options() -- all the attributes are
340         * already configured via configfs. Just print them out.
341         */
342        netpoll_print_options(&nt->np);
343
344        err = netpoll_setup(&nt->np);
345        if (err)
346            return err;
347
348        printk(KERN_INFO "netconsole: network logging started\n");
349
350    } else { /* 0 */
351        netpoll_cleanup(&nt->np);
352    }
353
354    nt->enabled = enabled;
355
356    return strnlen(buf, count);
357}
358
359static ssize_t store_dev_name(struct netconsole_target *nt,
360                  const char *buf,
361                  size_t count)
362{
363    size_t len;
364
365    if (nt->enabled) {
366        printk(KERN_ERR "netconsole: target (%s) is enabled, "
367                "disable to update parameters\n",
368                config_item_name(&nt->item));
369        return -EINVAL;
370    }
371
372    strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
373
374    /* Get rid of possible trailing newline from echo(1) */
375    len = strnlen(nt->np.dev_name, IFNAMSIZ);
376    if (nt->np.dev_name[len - 1] == '\n')
377        nt->np.dev_name[len - 1] = '\0';
378
379    return strnlen(buf, count);
380}
381
382static ssize_t store_local_port(struct netconsole_target *nt,
383                const char *buf,
384                size_t count)
385{
386    long local_port;
387#define __U16_MAX ((__u16) ~0U)
388
389    if (nt->enabled) {
390        printk(KERN_ERR "netconsole: target (%s) is enabled, "
391                "disable to update parameters\n",
392                config_item_name(&nt->item));
393        return -EINVAL;
394    }
395
396    local_port = strtol10_check_range(buf, 0, __U16_MAX);
397    if (local_port < 0)
398        return local_port;
399
400    nt->np.local_port = local_port;
401
402    return strnlen(buf, count);
403}
404
405static ssize_t store_remote_port(struct netconsole_target *nt,
406                 const char *buf,
407                 size_t count)
408{
409    long remote_port;
410#define __U16_MAX ((__u16) ~0U)
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    remote_port = strtol10_check_range(buf, 0, __U16_MAX);
420    if (remote_port < 0)
421        return remote_port;
422
423    nt->np.remote_port = remote_port;
424
425    return strnlen(buf, count);
426}
427
428static ssize_t store_local_ip(struct netconsole_target *nt,
429                  const char *buf,
430                  size_t count)
431{
432    if (nt->enabled) {
433        printk(KERN_ERR "netconsole: target (%s) is enabled, "
434                "disable to update parameters\n",
435                config_item_name(&nt->item));
436        return -EINVAL;
437    }
438
439    nt->np.local_ip = in_aton(buf);
440
441    return strnlen(buf, count);
442}
443
444static ssize_t store_remote_ip(struct netconsole_target *nt,
445                   const char *buf,
446                   size_t count)
447{
448    if (nt->enabled) {
449        printk(KERN_ERR "netconsole: target (%s) is enabled, "
450                "disable to update parameters\n",
451                config_item_name(&nt->item));
452        return -EINVAL;
453    }
454
455    nt->np.remote_ip = in_aton(buf);
456
457    return strnlen(buf, count);
458}
459
460static ssize_t store_remote_mac(struct netconsole_target *nt,
461                const char *buf,
462                size_t count)
463{
464    u8 remote_mac[ETH_ALEN];
465    char *p = (char *) buf;
466    int i;
467
468    if (nt->enabled) {
469        printk(KERN_ERR "netconsole: target (%s) is enabled, "
470                "disable to update parameters\n",
471                config_item_name(&nt->item));
472        return -EINVAL;
473    }
474
475    for (i = 0; i < ETH_ALEN - 1; i++) {
476        remote_mac[i] = simple_strtoul(p, &p, 16);
477        if (*p != ':')
478            goto invalid;
479        p++;
480    }
481    remote_mac[ETH_ALEN - 1] = simple_strtoul(p, &p, 16);
482    if (*p && (*p != '\n'))
483        goto invalid;
484
485    memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
486
487    return strnlen(buf, count);
488
489invalid:
490    printk(KERN_ERR "netconsole: invalid input\n");
491    return -EINVAL;
492}
493
494/*
495 * Attribute definitions for netconsole_target.
496 */
497
498#define NETCONSOLE_TARGET_ATTR_RO(_name) \
499static struct netconsole_target_attr netconsole_target_##_name = \
500    __CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
501
502#define NETCONSOLE_TARGET_ATTR_RW(_name) \
503static struct netconsole_target_attr netconsole_target_##_name = \
504    __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
505
506NETCONSOLE_TARGET_ATTR_RW(enabled);
507NETCONSOLE_TARGET_ATTR_RW(dev_name);
508NETCONSOLE_TARGET_ATTR_RW(local_port);
509NETCONSOLE_TARGET_ATTR_RW(remote_port);
510NETCONSOLE_TARGET_ATTR_RW(local_ip);
511NETCONSOLE_TARGET_ATTR_RW(remote_ip);
512NETCONSOLE_TARGET_ATTR_RO(local_mac);
513NETCONSOLE_TARGET_ATTR_RW(remote_mac);
514
515static struct configfs_attribute *netconsole_target_attrs[] = {
516    &netconsole_target_enabled.attr,
517    &netconsole_target_dev_name.attr,
518    &netconsole_target_local_port.attr,
519    &netconsole_target_remote_port.attr,
520    &netconsole_target_local_ip.attr,
521    &netconsole_target_remote_ip.attr,
522    &netconsole_target_local_mac.attr,
523    &netconsole_target_remote_mac.attr,
524    NULL,
525};
526
527/*
528 * Item operations and type for netconsole_target.
529 */
530
531static void netconsole_target_release(struct config_item *item)
532{
533    kfree(to_target(item));
534}
535
536static ssize_t netconsole_target_attr_show(struct config_item *item,
537                       struct configfs_attribute *attr,
538                       char *buf)
539{
540    ssize_t ret = -EINVAL;
541    struct netconsole_target *nt = to_target(item);
542    struct netconsole_target_attr *na =
543        container_of(attr, struct netconsole_target_attr, attr);
544
545    if (na->show)
546        ret = na->show(nt, buf);
547
548    return ret;
549}
550
551static ssize_t netconsole_target_attr_store(struct config_item *item,
552                        struct configfs_attribute *attr,
553                        const char *buf,
554                        size_t count)
555{
556    ssize_t ret = -EINVAL;
557    struct netconsole_target *nt = to_target(item);
558    struct netconsole_target_attr *na =
559        container_of(attr, struct netconsole_target_attr, attr);
560
561    if (na->store)
562        ret = na->store(nt, buf, count);
563
564    return ret;
565}
566
567static struct configfs_item_operations netconsole_target_item_ops = {
568    .release = netconsole_target_release,
569    .show_attribute = netconsole_target_attr_show,
570    .store_attribute = netconsole_target_attr_store,
571};
572
573static struct config_item_type netconsole_target_type = {
574    .ct_attrs = netconsole_target_attrs,
575    .ct_item_ops = &netconsole_target_item_ops,
576    .ct_owner = THIS_MODULE,
577};
578
579/*
580 * Group operations and type for netconsole_subsys.
581 */
582
583static struct config_item *make_netconsole_target(struct config_group *group,
584                          const char *name)
585{
586    unsigned long flags;
587    struct netconsole_target *nt;
588
589    /*
590     * Allocate and initialize with defaults.
591     * Target is disabled at creation (enabled == 0).
592     */
593    nt = kzalloc(sizeof(*nt), GFP_KERNEL);
594    if (!nt) {
595        printk(KERN_ERR "netconsole: failed to allocate memory\n");
596        return ERR_PTR(-ENOMEM);
597    }
598
599    nt->np.name = "netconsole";
600    strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
601    nt->np.local_port = 6665;
602    nt->np.remote_port = 6666;
603    memset(nt->np.remote_mac, 0xff, ETH_ALEN);
604
605    /* Initialize the config_item member */
606    config_item_init_type_name(&nt->item, name, &netconsole_target_type);
607
608    /* Adding, but it is disabled */
609    spin_lock_irqsave(&target_list_lock, flags);
610    list_add(&nt->list, &target_list);
611    spin_unlock_irqrestore(&target_list_lock, flags);
612
613    return &nt->item;
614}
615
616static void drop_netconsole_target(struct config_group *group,
617                   struct config_item *item)
618{
619    unsigned long flags;
620    struct netconsole_target *nt = to_target(item);
621
622    spin_lock_irqsave(&target_list_lock, flags);
623    list_del(&nt->list);
624    spin_unlock_irqrestore(&target_list_lock, flags);
625
626    /*
627     * The target may have never been enabled, or was manually disabled
628     * before being removed so netpoll may have already been cleaned up.
629     */
630    if (nt->enabled)
631        netpoll_cleanup(&nt->np);
632
633    config_item_put(&nt->item);
634}
635
636static struct configfs_group_operations netconsole_subsys_group_ops = {
637    .make_item = make_netconsole_target,
638    .drop_item = drop_netconsole_target,
639};
640
641static struct config_item_type netconsole_subsys_type = {
642    .ct_group_ops = &netconsole_subsys_group_ops,
643    .ct_owner = THIS_MODULE,
644};
645
646/* The netconsole configfs subsystem */
647static struct configfs_subsystem netconsole_subsys = {
648    .su_group = {
649        .cg_item = {
650            .ci_namebuf = "netconsole",
651            .ci_type = &netconsole_subsys_type,
652        },
653    },
654};
655
656#endif /* CONFIG_NETCONSOLE_DYNAMIC */
657
658/* Handle network interface device notifications */
659static int netconsole_netdev_event(struct notifier_block *this,
660                   unsigned long event,
661                   void *ptr)
662{
663    unsigned long flags;
664    struct netconsole_target *nt;
665    struct net_device *dev = ptr;
666
667    if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER))
668        goto done;
669
670    spin_lock_irqsave(&target_list_lock, flags);
671    list_for_each_entry(nt, &target_list, list) {
672        netconsole_target_get(nt);
673        if (nt->np.dev == dev) {
674            switch (event) {
675            case NETDEV_CHANGENAME:
676                strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
677                break;
678            case NETDEV_UNREGISTER:
679                if (!nt->enabled)
680                    break;
681                netpoll_cleanup(&nt->np);
682                nt->enabled = 0;
683                printk(KERN_INFO "netconsole: network logging stopped"
684                    ", interface %s unregistered\n",
685                    dev->name);
686                break;
687            }
688        }
689        netconsole_target_put(nt);
690    }
691    spin_unlock_irqrestore(&target_list_lock, flags);
692
693done:
694    return NOTIFY_DONE;
695}
696
697static struct notifier_block netconsole_netdev_notifier = {
698    .notifier_call = netconsole_netdev_event,
699};
700
701static void write_msg(struct console *con, const char *msg, unsigned int len)
702{
703    int frag, left;
704    unsigned long flags;
705    struct netconsole_target *nt;
706    const char *tmp;
707
708    /* Avoid taking lock and disabling interrupts unnecessarily */
709    if (list_empty(&target_list))
710        return;
711
712    spin_lock_irqsave(&target_list_lock, flags);
713    list_for_each_entry(nt, &target_list, list) {
714        netconsole_target_get(nt);
715        if (nt->enabled && netif_running(nt->np.dev)) {
716            /*
717             * We nest this inside the for-each-target loop above
718             * so that we're able to get as much logging out to
719             * at least one target if we die inside here, instead
720             * of unnecessarily keeping all targets in lock-step.
721             */
722            tmp = msg;
723            for (left = len; left;) {
724                frag = min(left, MAX_PRINT_CHUNK);
725                netpoll_send_udp(&nt->np, tmp, frag);
726                tmp += frag;
727                left -= frag;
728            }
729        }
730        netconsole_target_put(nt);
731    }
732    spin_unlock_irqrestore(&target_list_lock, flags);
733}
734
735static struct console netconsole = {
736    .name = "netcon",
737    .flags = CON_ENABLED,
738    .write = write_msg,
739};
740
741static int __init init_netconsole(void)
742{
743    int err;
744    struct netconsole_target *nt, *tmp;
745    unsigned long flags;
746    char *target_config;
747    char *input = config;
748
749    if (strnlen(input, MAX_PARAM_LENGTH)) {
750        while ((target_config = strsep(&input, ";"))) {
751            nt = alloc_param_target(target_config);
752            if (IS_ERR(nt)) {
753                err = PTR_ERR(nt);
754                goto fail;
755            }
756            /* Dump existing printks when we register */
757            netconsole.flags |= CON_PRINTBUFFER;
758
759            spin_lock_irqsave(&target_list_lock, flags);
760            list_add(&nt->list, &target_list);
761            spin_unlock_irqrestore(&target_list_lock, flags);
762        }
763    }
764
765    err = register_netdevice_notifier(&netconsole_netdev_notifier);
766    if (err)
767        goto fail;
768
769    err = dynamic_netconsole_init();
770    if (err)
771        goto undonotifier;
772
773    register_console(&netconsole);
774    printk(KERN_INFO "netconsole: network logging started\n");
775
776    return err;
777
778undonotifier:
779    unregister_netdevice_notifier(&netconsole_netdev_notifier);
780
781fail:
782    printk(KERN_ERR "netconsole: cleaning up\n");
783
784    /*
785     * Remove all targets and destroy them (only targets created
786     * from the boot/module option exist here). Skipping the list
787     * lock is safe here, and netpoll_cleanup() will sleep.
788     */
789    list_for_each_entry_safe(nt, tmp, &target_list, list) {
790        list_del(&nt->list);
791        free_param_target(nt);
792    }
793
794    return err;
795}
796
797static void __exit cleanup_netconsole(void)
798{
799    struct netconsole_target *nt, *tmp;
800
801    unregister_console(&netconsole);
802    dynamic_netconsole_exit();
803    unregister_netdevice_notifier(&netconsole_netdev_notifier);
804
805    /*
806     * Targets created via configfs pin references on our module
807     * and would first be rmdir(2)'ed from userspace. We reach
808     * here only when they are already destroyed, and only those
809     * created from the boot/module option are left, so remove and
810     * destroy them. Skipping the list lock is safe here, and
811     * netpoll_cleanup() will sleep.
812     */
813    list_for_each_entry_safe(nt, tmp, &target_list, list) {
814        list_del(&nt->list);
815        free_param_target(nt);
816    }
817}
818
819module_init(init_netconsole);
820module_exit(cleanup_netconsole);
821

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