[mirror_ubuntu-zesty-kernel.git] / net / core / drop_monitor.c

/*
 * Monitoring code for network dropped packet alerts
 *
 * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com>
 */

#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/string.h>
#include <linux/if_arp.h>
#include <linux/inetdevice.h>
#include <linux/inet.h>
#include <linux/interrupt.h>
#include <linux/netpoll.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <linux/netlink.h>
#include <linux/net_dropmon.h>
#include <linux/percpu.h>
#include <linux/timer.h>
#include <linux/bitops.h>
#include <net/genetlink.h>
#include <net/netevent.h>

#include <trace/events/skb.h>
#include <trace/events/napi.h>

#include <asm/unaligned.h>

#define TRACE_ON 1
#define TRACE_OFF 0

static void send_dm_alert(struct work_struct *unused);


/*
 * Globals, our netlink socket pointer
 * and the work handle that will send up
 * netlink alerts
 */
static int trace_state = TRACE_OFF;
static spinlock_t trace_state_lock = SPIN_LOCK_UNLOCKED;

struct per_cpu_dm_data {
	struct work_struct dm_alert_work;
	struct sk_buff *skb;
	atomic_t dm_hit_count;
	struct timer_list send_timer;
};

struct dm_hw_stat_delta {
	struct net_device *dev;
	struct list_head list;
	struct rcu_head rcu;
	unsigned long last_drop_val;
};

static struct genl_family net_drop_monitor_family = {
	.id             = GENL_ID_GENERATE,
	.hdrsize        = 0,
	.name           = "NET_DM",
	.version        = 2,
	.maxattr        = NET_DM_CMD_MAX,
};

static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);

static int dm_hit_limit = 64;
static int dm_delay = 1;
static unsigned long dm_hw_check_delta = 2*HZ;
static LIST_HEAD(hw_stats_list);

static void reset_per_cpu_data(struct per_cpu_dm_data *data)
{
	size_t al;
	struct net_dm_alert_msg *msg;
	struct nlattr *nla;

	al = sizeof(struct net_dm_alert_msg);
	al += dm_hit_limit * sizeof(struct net_dm_drop_point);
	al += sizeof(struct nlattr);

	data->skb = genlmsg_new(al, GFP_KERNEL);
	genlmsg_put(data->skb, 0, 0, &net_drop_monitor_family,
			0, NET_DM_CMD_ALERT);
	nla = nla_reserve(data->skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg));
	msg = nla_data(nla);
	memset(msg, 0, al);
	atomic_set(&data->dm_hit_count, dm_hit_limit);
}

static void send_dm_alert(struct work_struct *unused)
{
	struct sk_buff *skb;
	struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);

	/*
	 * Grab the skb we're about to send
	 */
	skb = data->skb;

	/*
	 * Replace it with a new one
	 */
	reset_per_cpu_data(data);

	/*
	 * Ship it!
	 */
	genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);

}

/*
 * This is the timer function to delay the sending of an alert
 * in the event that more drops will arrive during the
 * hysteresis period.  Note that it operates under the timer interrupt
 * so we don't need to disable preemption here
 */
static void sched_send_work(unsigned long unused)
{
	struct per_cpu_dm_data *data =  &__get_cpu_var(dm_cpu_data);

	schedule_work(&data->dm_alert_work);
}

static void trace_drop_common(struct sk_buff *skb, void *location)
{
	struct net_dm_alert_msg *msg;
	struct nlmsghdr *nlh;
	struct nlattr *nla;
	int i;
	struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);


	if (!atomic_add_unless(&data->dm_hit_count, -1, 0)) {
		/*
		 * we're already at zero, discard this hit
		 */
		goto out;
	}

	nlh = (struct nlmsghdr *)data->skb->data;
	nla = genlmsg_data(nlmsg_data(nlh));
	msg = nla_data(nla);
	for (i = 0; i < msg->entries; i++) {
		if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) {
			msg->points[i].count++;
			goto out;
		}
	}

	/*
	 * We need to create a new entry
	 */
	__nla_reserve_nohdr(data->skb, sizeof(struct net_dm_drop_point));
	nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
	memcpy(msg->points[msg->entries].pc, &location, sizeof(void *));
	msg->points[msg->entries].count = 1;
	msg->entries++;

	if (!timer_pending(&data->send_timer)) {
		data->send_timer.expires = jiffies + dm_delay * HZ;
		add_timer_on(&data->send_timer, smp_processor_id());
	}

out:
	return;
}

static void trace_kfree_skb_hit(struct sk_buff *skb, void *location)
{
	trace_drop_common(skb, location);
}

static void trace_napi_poll_hit(struct napi_struct *napi)
{
	struct dm_hw_stat_delta *new_stat;

	/*
	 * Ratelimit our check time to dm_hw_check_delta jiffies
	 */
	if (!napi->dev ||
	    !time_after(jiffies, napi->dev->last_rx + dm_hw_check_delta))
		return;

	rcu_read_lock();
	list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
		if ((new_stat->dev == napi->dev)  &&
		    (napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
			trace_drop_common(NULL, NULL);
			new_stat->last_drop_val = napi->dev->stats.rx_dropped;
			break;
		}
	}
	rcu_read_unlock();
}


static void free_dm_hw_stat(struct rcu_head *head)
{
	struct dm_hw_stat_delta *n;
	n = container_of(head, struct dm_hw_stat_delta, rcu);
	kfree(n);
}

static int set_all_monitor_traces(int state)
{
	int rc = 0;
	struct dm_hw_stat_delta *new_stat = NULL;
	struct dm_hw_stat_delta *temp;

	spin_lock(&trace_state_lock);

	switch (state) {
	case TRACE_ON:
		rc |= register_trace_kfree_skb(trace_kfree_skb_hit);
		rc |= register_trace_napi_poll(trace_napi_poll_hit);
		break;
	case TRACE_OFF:
		rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit);
		rc |= unregister_trace_napi_poll(trace_napi_poll_hit);

		tracepoint_synchronize_unregister();

		/*
		 * Clean the device list
		 */
		list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
			if (new_stat->dev == NULL) {
				list_del_rcu(&new_stat->list);
				call_rcu(&new_stat->rcu, free_dm_hw_stat);
			}
		}
		break;
	default:
		rc = 1;
		break;
	}

	if (!rc)
		trace_state = state;

	spin_unlock(&trace_state_lock);

	if (rc)
		return -EINPROGRESS;
	return rc;
}


static int net_dm_cmd_config(struct sk_buff *skb,
			struct genl_info *info)
{
	return -ENOTSUPP;
}

static int net_dm_cmd_trace(struct sk_buff *skb,
			struct genl_info *info)
{
	switch (info->genlhdr->cmd) {
	case NET_DM_CMD_START:
		return set_all_monitor_traces(TRACE_ON);
		break;
	case NET_DM_CMD_STOP:
		return set_all_monitor_traces(TRACE_OFF);
		break;
	}

	return -ENOTSUPP;
}

static int dropmon_net_event(struct notifier_block *ev_block,
			unsigned long event, void *ptr)
{
	struct net_device *dev = ptr;
	struct dm_hw_stat_delta *new_stat = NULL;
	struct dm_hw_stat_delta *tmp;

	switch (event) {
	case NETDEV_REGISTER:
		new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);

		if (!new_stat)
			goto out;

		new_stat->dev = dev;
		INIT_RCU_HEAD(&new_stat->rcu);
		spin_lock(&trace_state_lock);
		list_add_rcu(&new_stat->list, &hw_stats_list);
		spin_unlock(&trace_state_lock);
		break;
	case NETDEV_UNREGISTER:
		spin_lock(&trace_state_lock);
		list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
			if (new_stat->dev == dev) {
				new_stat->dev = NULL;
				if (trace_state == TRACE_OFF) {
					list_del_rcu(&new_stat->list);
					call_rcu(&new_stat->rcu, free_dm_hw_stat);
					break;
				}
			}
		}
		spin_unlock(&trace_state_lock);
		break;
	}
out:
	return NOTIFY_DONE;
}

static struct genl_ops dropmon_ops[] = {
	{
		.cmd = NET_DM_CMD_CONFIG,
		.doit = net_dm_cmd_config,
	},
	{
		.cmd = NET_DM_CMD_START,
		.doit = net_dm_cmd_trace,
	},
	{
		.cmd = NET_DM_CMD_STOP,
		.doit = net_dm_cmd_trace,
	},
};

static struct notifier_block dropmon_net_notifier = {
	.notifier_call = dropmon_net_event
};

static int __init init_net_drop_monitor(void)
{
	int cpu;
	int rc, i, ret;
	struct per_cpu_dm_data *data;
	printk(KERN_INFO "Initalizing network drop monitor service\n");

	if (sizeof(void *) > 8) {
		printk(KERN_ERR "Unable to store program counters on this arch, Drop monitor failed\n");
		return -ENOSPC;
	}

	if (genl_register_family(&net_drop_monitor_family) < 0) {
		printk(KERN_ERR "Could not create drop monitor netlink family\n");
		return -EFAULT;
	}

	rc = -EFAULT;

	for (i = 0; i < ARRAY_SIZE(dropmon_ops); i++) {
		ret = genl_register_ops(&net_drop_monitor_family,
					&dropmon_ops[i]);
		if (ret) {
			printk(KERN_CRIT "Failed to register operation %d\n",
				dropmon_ops[i].cmd);
			goto out_unreg;
		}
	}

	rc = register_netdevice_notifier(&dropmon_net_notifier);
	if (rc < 0) {
		printk(KERN_CRIT "Failed to register netdevice notifier\n");
		goto out_unreg;
	}

	rc = 0;

	for_each_present_cpu(cpu) {
		data = &per_cpu(dm_cpu_data, cpu);
		reset_per_cpu_data(data);
		INIT_WORK(&data->dm_alert_work, send_dm_alert);
		init_timer(&data->send_timer);
		data->send_timer.data = cpu;
		data->send_timer.function = sched_send_work;
	}

	goto out;

out_unreg:
	genl_unregister_family(&net_drop_monitor_family);
out:
	return rc;
}

late_initcall(init_net_drop_monitor);
Commit	Line	Data
9a8afc8d NH	1	/*
	2	* Monitoring code for network dropped packet alerts
	3	*
	4	* Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com>
	5	*/
	6
	7	#include <linux/netdevice.h>
	8	#include <linux/etherdevice.h>
	9	#include <linux/string.h>
	10	#include <linux/if_arp.h>
	11	#include <linux/inetdevice.h>
	12	#include <linux/inet.h>
	13	#include <linux/interrupt.h>
	14	#include <linux/netpoll.h>
	15	#include <linux/sched.h>
	16	#include <linux/delay.h>
	17	#include <linux/types.h>
	18	#include <linux/workqueue.h>
	19	#include <linux/netlink.h>
	20	#include <linux/net_dropmon.h>
	21	#include <linux/percpu.h>
	22	#include <linux/timer.h>
	23	#include <linux/bitops.h>
	24	#include <net/genetlink.h>
4ea7e386	25	#include <net/netevent.h>
9a8afc8d	26
ad8d75ff	27	#include <trace/events/skb.h>
9cbc1cb8	28	#include <trace/events/napi.h>
9a8afc8d NH	29
	30	#include <asm/unaligned.h>
	31
	32	#define TRACE_ON 1
	33	#define TRACE_OFF 0
	34
	35	static void send_dm_alert(struct work_struct *unused);
	36
	37
	38	/*
	39	* Globals, our netlink socket pointer
	40	* and the work handle that will send up
	41	* netlink alerts
	42	*/
4ea7e386 NH	43	static int trace_state = TRACE_OFF;
4ea7e386 NH	44	static spinlock_t trace_state_lock = SPIN_LOCK_UNLOCKED;
9a8afc8d NH	45
	46	struct per_cpu_dm_data {
	47	struct work_struct dm_alert_work;
	48	struct sk_buff *skb;
	49	atomic_t dm_hit_count;
	50	struct timer_list send_timer;
	51	};
	52
4ea7e386 NH	53	struct dm_hw_stat_delta {
	54	struct net_device *dev;
	55	struct list_head list;
	56	struct rcu_head rcu;
	57	unsigned long last_drop_val;
	58	};
	59
9a8afc8d NH	60	static struct genl_family net_drop_monitor_family = {
	61	.id = GENL_ID_GENERATE,
	62	.hdrsize = 0,
	63	.name = "NET_DM",
683703a2	64	.version = 2,
9a8afc8d NH	65	.maxattr = NET_DM_CMD_MAX,
	66	};
	67
	68	static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
	69
	70	static int dm_hit_limit = 64;
	71	static int dm_delay = 1;
4ea7e386 NH	72	static unsigned long dm_hw_check_delta = 2*HZ;
4ea7e386 NH	73	static LIST_HEAD(hw_stats_list);
9a8afc8d NH	74
	75	static void reset_per_cpu_data(struct per_cpu_dm_data *data)
	76	{
	77	size_t al;
	78	struct net_dm_alert_msg *msg;
683703a2	79	struct nlattr *nla;
9a8afc8d NH	80
	81	al = sizeof(struct net_dm_alert_msg);
	82	al += dm_hit_limit * sizeof(struct net_dm_drop_point);
683703a2 NH	83	al += sizeof(struct nlattr);
683703a2 NH	84
9a8afc8d NH	85	data->skb = genlmsg_new(al, GFP_KERNEL);
	86	genlmsg_put(data->skb, 0, 0, &net_drop_monitor_family,
	87	0, NET_DM_CMD_ALERT);
683703a2 NH	88	nla = nla_reserve(data->skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg));
683703a2 NH	89	msg = nla_data(nla);
9a8afc8d NH	90	memset(msg, 0, al);
	91	atomic_set(&data->dm_hit_count, dm_hit_limit);
	92	}
	93
	94	static void send_dm_alert(struct work_struct *unused)
	95	{
	96	struct sk_buff *skb;
	97	struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
	98
	99	/*
	100	* Grab the skb we're about to send
	101	*/
	102	skb = data->skb;
	103
	104	/*
	105	* Replace it with a new one
	106	*/
	107	reset_per_cpu_data(data);
	108
	109	/*
	110	* Ship it!
	111	*/
	112	genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);
	113
	114	}
	115
	116	/*
	117	* This is the timer function to delay the sending of an alert
	118	* in the event that more drops will arrive during the
	119	* hysteresis period. Note that it operates under the timer interrupt
	120	* so we don't need to disable preemption here
	121	*/
	122	static void sched_send_work(unsigned long unused)
	123	{
	124	struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
	125
	126	schedule_work(&data->dm_alert_work);
	127	}
	128
4ea7e386	129	static void trace_drop_common(struct sk_buff skb, void location)
9a8afc8d NH	130	{
	131	struct net_dm_alert_msg *msg;
	132	struct nlmsghdr *nlh;
683703a2	133	struct nlattr *nla;
9a8afc8d NH	134	int i;
	135	struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
	136
	137
	138	if (!atomic_add_unless(&data->dm_hit_count, -1, 0)) {
	139	/*
	140	* we're already at zero, discard this hit
	141	*/
	142	goto out;
	143	}
	144
	145	nlh = (struct nlmsghdr *)data->skb->data;
683703a2 NH	146	nla = genlmsg_data(nlmsg_data(nlh));
683703a2 NH	147	msg = nla_data(nla);
9a8afc8d NH	148	for (i = 0; i < msg->entries; i++) {
	149	if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) {
	150	msg->points[i].count++;
	151	goto out;
	152	}
	153	}
	154
	155	/*
	156	* We need to create a new entry
	157	*/
	158	__nla_reserve_nohdr(data->skb, sizeof(struct net_dm_drop_point));
683703a2	159	nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
9a8afc8d NH	160	memcpy(msg->points[msg->entries].pc, &location, sizeof(void *));
	161	msg->points[msg->entries].count = 1;
	162	msg->entries++;
	163
	164	if (!timer_pending(&data->send_timer)) {
	165	data->send_timer.expires = jiffies + dm_delay * HZ;
	166	add_timer_on(&data->send_timer, smp_processor_id());
	167	}
	168
	169	out:
	170	return;
	171	}
	172
4ea7e386 NH	173	static void trace_kfree_skb_hit(struct sk_buff skb, void location)
	174	{
	175	trace_drop_common(skb, location);
	176	}
	177
	178	static void trace_napi_poll_hit(struct napi_struct *napi)
	179	{
	180	struct dm_hw_stat_delta *new_stat;
	181
	182	/*
	183	* Ratelimit our check time to dm_hw_check_delta jiffies
	184	*/
f2798eb4 XG	185	if (!napi->dev \|\|
f2798eb4 XG	186	!time_after(jiffies, napi->dev->last_rx + dm_hw_check_delta))
4ea7e386 NH	187	return;
	188
	189	rcu_read_lock();
	190	list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
	191	if ((new_stat->dev == napi->dev) &&
	192	(napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
	193	trace_drop_common(NULL, NULL);
	194	new_stat->last_drop_val = napi->dev->stats.rx_dropped;
	195	break;
	196	}
	197	}
	198	rcu_read_unlock();
	199	}
	200
	201
	202	static void free_dm_hw_stat(struct rcu_head *head)
	203	{
	204	struct dm_hw_stat_delta *n;
	205	n = container_of(head, struct dm_hw_stat_delta, rcu);
	206	kfree(n);
	207	}
	208
9a8afc8d NH	209	static int set_all_monitor_traces(int state)
	210	{
	211	int rc = 0;
4ea7e386 NH	212	struct dm_hw_stat_delta *new_stat = NULL;
	213	struct dm_hw_stat_delta *temp;
	214
	215	spin_lock(&trace_state_lock);
9a8afc8d NH	216
	217	switch (state) {
	218	case TRACE_ON:
	219	rc \|= register_trace_kfree_skb(trace_kfree_skb_hit);
4ea7e386	220	rc \|= register_trace_napi_poll(trace_napi_poll_hit);
9a8afc8d NH	221	break;
	222	case TRACE_OFF:
	223	rc \|= unregister_trace_kfree_skb(trace_kfree_skb_hit);
4ea7e386	224	rc \|= unregister_trace_napi_poll(trace_napi_poll_hit);
9a8afc8d NH	225
9a8afc8d NH	226	tracepoint_synchronize_unregister();
4ea7e386 NH	227
	228	/*
	229	* Clean the device list
	230	*/
	231	list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
	232	if (new_stat->dev == NULL) {
	233	list_del_rcu(&new_stat->list);
	234	call_rcu(&new_stat->rcu, free_dm_hw_stat);
	235	}
	236	}
9a8afc8d NH	237	break;
	238	default:
	239	rc = 1;
	240	break;
	241	}
	242
4ea7e386 NH	243	if (!rc)
	244	trace_state = state;
	245
	246	spin_unlock(&trace_state_lock);
	247
9a8afc8d NH	248	if (rc)
	249	return -EINPROGRESS;
	250	return rc;
	251	}
	252
	253
	254	static int net_dm_cmd_config(struct sk_buff *skb,
	255	struct genl_info *info)
	256	{
	257	return -ENOTSUPP;
	258	}
	259
	260	static int net_dm_cmd_trace(struct sk_buff *skb,
	261	struct genl_info *info)
	262	{
	263	switch (info->genlhdr->cmd) {
	264	case NET_DM_CMD_START:
	265	return set_all_monitor_traces(TRACE_ON);
	266	break;
	267	case NET_DM_CMD_STOP:
	268	return set_all_monitor_traces(TRACE_OFF);
	269	break;
	270	}
	271
	272	return -ENOTSUPP;
	273	}
	274
4ea7e386 NH	275	static int dropmon_net_event(struct notifier_block *ev_block,
	276	unsigned long event, void *ptr)
	277	{
	278	struct net_device *dev = ptr;
	279	struct dm_hw_stat_delta *new_stat = NULL;
	280	struct dm_hw_stat_delta *tmp;
	281
	282	switch (event) {
	283	case NETDEV_REGISTER:
	284	new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);
	285
	286	if (!new_stat)
	287	goto out;
	288
	289	new_stat->dev = dev;
	290	INIT_RCU_HEAD(&new_stat->rcu);
	291	spin_lock(&trace_state_lock);
	292	list_add_rcu(&new_stat->list, &hw_stats_list);
	293	spin_unlock(&trace_state_lock);
	294	break;
	295	case NETDEV_UNREGISTER:
	296	spin_lock(&trace_state_lock);
	297	list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
	298	if (new_stat->dev == dev) {
	299	new_stat->dev = NULL;
	300	if (trace_state == TRACE_OFF) {
	301	list_del_rcu(&new_stat->list);
	302	call_rcu(&new_stat->rcu, free_dm_hw_stat);
	303	break;
	304	}
	305	}
	306	}
	307	spin_unlock(&trace_state_lock);
	308	break;
	309	}
	310	out:
	311	return NOTIFY_DONE;
	312	}
9a8afc8d NH	313
	314	static struct genl_ops dropmon_ops[] = {
	315	{
	316	.cmd = NET_DM_CMD_CONFIG,
	317	.doit = net_dm_cmd_config,
	318	},
	319	{
	320	.cmd = NET_DM_CMD_START,
	321	.doit = net_dm_cmd_trace,
	322	},
	323	{
	324	.cmd = NET_DM_CMD_STOP,
	325	.doit = net_dm_cmd_trace,
	326	},
	327	};
	328
4ea7e386 NH	329	static struct notifier_block dropmon_net_notifier = {
	330	.notifier_call = dropmon_net_event
	331	};
	332
9a8afc8d NH	333	static int __init init_net_drop_monitor(void)
	334	{
	335	int cpu;
	336	int rc, i, ret;
	337	struct per_cpu_dm_data *data;
	338	printk(KERN_INFO "Initalizing network drop monitor service\n");
	339
	340	if (sizeof(void *) > 8) {
	341	printk(KERN_ERR "Unable to store program counters on this arch, Drop monitor failed\n");
	342	return -ENOSPC;
	343	}
	344
	345	if (genl_register_family(&net_drop_monitor_family) < 0) {
	346	printk(KERN_ERR "Could not create drop monitor netlink family\n");
	347	return -EFAULT;
	348	}
	349
	350	rc = -EFAULT;
	351
	352	for (i = 0; i < ARRAY_SIZE(dropmon_ops); i++) {
	353	ret = genl_register_ops(&net_drop_monitor_family,
	354	&dropmon_ops[i]);
	355	if (ret) {
4ea7e386	356	printk(KERN_CRIT "Failed to register operation %d\n",
9a8afc8d NH	357	dropmon_ops[i].cmd);
	358	goto out_unreg;
	359	}
	360	}
	361
4ea7e386 NH	362	rc = register_netdevice_notifier(&dropmon_net_notifier);
	363	if (rc < 0) {
	364	printk(KERN_CRIT "Failed to register netdevice notifier\n");
	365	goto out_unreg;
	366	}
	367
9a8afc8d NH	368	rc = 0;
	369
	370	for_each_present_cpu(cpu) {
	371	data = &per_cpu(dm_cpu_data, cpu);
	372	reset_per_cpu_data(data);
	373	INIT_WORK(&data->dm_alert_work, send_dm_alert);
	374	init_timer(&data->send_timer);
	375	data->send_timer.data = cpu;
	376	data->send_timer.function = sched_send_work;
	377	}
4ea7e386	378
9a8afc8d NH	379	goto out;
	380
	381	out_unreg:
	382	genl_unregister_family(&net_drop_monitor_family);
	383	out:
	384	return rc;
	385	}
	386
	387	late_initcall(init_net_drop_monitor);