[lttng-ust.git] / liblttng-ust / ltt-probes.c

/*
 * ltt-probes.c
 *
 * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Holds LTTng probes registry.
 *
 * Dual LGPL v2.1/GPL v2 license.
 */

#include <string.h>
#include <errno.h>
#include <urcu/list.h>
#include <urcu/hlist.h>
#include <lttng/ust-events.h>
#include <assert.h>
#include <helper.h>

#include "ltt-tracer-core.h"
#include "jhash.h"
#include "error.h"

/*
 * probe list is protected by ust_lock()/ust_unlock().
 */
static CDS_LIST_HEAD(probe_list);

/*
 * Loglevel hash table, containing the active loglevels.
 * Protected by ust lock.
 */
#define LOGLEVEL_HASH_BITS 6
#define LOGLEVEL_TABLE_SIZE (1 << LOGLEVEL_HASH_BITS)
static struct cds_hlist_head loglevel_table[LOGLEVEL_TABLE_SIZE];

static
const struct lttng_probe_desc *find_provider(const char *provider)
{
	struct lttng_probe_desc *iter;

	cds_list_for_each_entry(iter, &probe_list, head) {
		if (!strcmp(iter->provider, provider))
			return iter;
	}
	return NULL;
}

static
const struct lttng_event_desc *find_event(const char *name)
{
	struct lttng_probe_desc *probe_desc;
	int i;

	cds_list_for_each_entry(probe_desc, &probe_list, head) {
		for (i = 0; i < probe_desc->nr_events; i++) {
			if (!strcmp(probe_desc->event_desc[i]->name, name))
				return probe_desc->event_desc[i];
		}
	}
	return NULL;
}

int ltt_probe_register(struct lttng_probe_desc *desc)
{
	struct lttng_probe_desc *iter;
	int ret = 0;
	int i;

	ust_lock();
	if (find_provider(desc->provider)) {
		ret = -EEXIST;
		goto end;
	}
	/*
	 * TODO: This is O(N^2). Turn into a hash table when probe registration
	 * overhead becomes an issue.
	 */
	for (i = 0; i < desc->nr_events; i++) {
		if (find_event(desc->event_desc[i]->name)) {
			ret = -EEXIST;
			goto end;
		}
	}

	/*
	 * We sort the providers by struct lttng_probe_desc pointer
	 * address.
	 */
	cds_list_for_each_entry_reverse(iter, &probe_list, head) {
		BUG_ON(iter == desc); /* Should never be in the list twice */
		if (iter < desc) {
			/* We belong to the location right after iter. */
			cds_list_add(&desc->head, &iter->head);
			goto desc_added;
		}
	}
	/* We should be added at the head of the list */
	cds_list_add(&desc->head, &probe_list);
desc_added:

	/*
	 * fix the events awaiting probe load.
	 */
	for (i = 0; i < desc->nr_events; i++) {
		ret = pending_probe_fix_events(desc->event_desc[i]);
		assert(!ret);
	}
end:
	ust_unlock();
	return ret;
}

void ltt_probe_unregister(struct lttng_probe_desc *desc)
{
	ust_lock();
	cds_list_del(&desc->head);
	ust_unlock();
}

/*
 * called with UST lock held.
 */
const struct lttng_event_desc *ltt_event_get(const char *name)
{
	const struct lttng_event_desc *event;

	event = find_event(name);
	if (!event)
		return NULL;
	return event;
}

void ltt_event_put(const struct lttng_event_desc *event)
{
}

void ltt_probes_prune_event_list(struct lttng_ust_tracepoint_list *list)
{
	struct tp_list_entry *list_entry, *tmp;

	cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) {
		cds_list_del(&list_entry->head);
		free(list_entry);
	}
}

/*
 * called with UST lock held.
 */
int ltt_probes_get_event_list(struct lttng_ust_tracepoint_list *list)
{
	struct lttng_probe_desc *probe_desc;
	int i;

	CDS_INIT_LIST_HEAD(&list->head);
	cds_list_for_each_entry(probe_desc, &probe_list, head) {
		for (i = 0; i < probe_desc->nr_events; i++) {
			struct tp_list_entry *list_entry;

			list_entry = zmalloc(sizeof(*list_entry));
			if (!list_entry)
				goto err_nomem;
			cds_list_add(&list_entry->head, &list->head);
			strncpy(list_entry->tp.name,
				probe_desc->event_desc[i]->name,
				LTTNG_UST_SYM_NAME_LEN);
			list_entry->tp.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
			if (!probe_desc->event_desc[i]->loglevel) {
				list_entry->tp.loglevel[0] = '\0';
				list_entry->tp.loglevel_value = 0;
			} else {
				strncpy(list_entry->tp.loglevel,
					(*probe_desc->event_desc[i]->loglevel)->identifier,
					LTTNG_UST_SYM_NAME_LEN);
				list_entry->tp.loglevel[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
				list_entry->tp.loglevel_value =
					(*probe_desc->event_desc[i]->loglevel)->value;
			}
		}
	}
	if (cds_list_empty(&list->head))
		list->iter = NULL;
	else
		list->iter =
			cds_list_first_entry(&list->head, struct tp_list_entry, head);
	return 0;

err_nomem:
	ltt_probes_prune_event_list(list);
	return -ENOMEM;
}

/*
 * Return current iteration position, advance internal iterator to next.
 * Return NULL if end of list.
 */
struct lttng_ust_tracepoint_iter *
	lttng_ust_tracepoint_list_get_iter_next(struct lttng_ust_tracepoint_list *list)
{
	struct tp_list_entry *entry;

	if (!list->iter)
		return NULL;
	entry = list->iter;
	if (entry->head.next == &list->head)
		list->iter = NULL;
	else
		list->iter = cds_list_entry(entry->head.next,
				struct tp_list_entry, head);
	return &entry->tp;
}

/*
 * Get loglevel if the loglevel is present in the loglevel hash table.
 * Must be called with ust lock held.
 * Returns NULL if not present.
 */
struct loglevel_entry *get_loglevel(const char *name)
{
	struct cds_hlist_head *head;
	struct cds_hlist_node *node;
	struct loglevel_entry *e;
	uint32_t hash = jhash(name, strlen(name), 0);

	head = &loglevel_table[hash & (LOGLEVEL_TABLE_SIZE - 1)];
	cds_hlist_for_each_entry(e, node, head, hlist) {
		if (!strcmp(name, e->name))
			return e;
	}
	return NULL;
}

/*
 * marshall all probes/all events and create those that fit the
 * loglevel. Add them to the events list as created.
 */
static
void _probes_create_loglevel_events(struct loglevel_entry *entry,
				struct session_loglevel *loglevel)
{
	struct lttng_probe_desc *probe_desc;
	struct lttng_ust_event event_param;
	int i;

	cds_list_for_each_entry(probe_desc, &probe_list, head) {
		for (i = 0; i < probe_desc->nr_events; i++) {
			const struct tracepoint_loglevel_entry *ev_ll;
			const struct lttng_event_desc *event_desc;

			event_desc = probe_desc->event_desc[i];
			if (!(event_desc->loglevel))
				continue;
			ev_ll = *event_desc->loglevel;
			if (!strcmp(ev_ll->identifier, entry->name)) {
				struct ltt_event *ev;
				int ret;

				memcpy(&event_param, &loglevel->event_param,
						sizeof(event_param));
				memcpy(event_param.name,
					event_desc->name,
					sizeof(event_param.name));
				/* create event */
				ret = ltt_event_create(loglevel->chan,
					&event_param, NULL,
					&ev);
				if (ret) {
					DBG("Error creating event");
					continue;
				}
				cds_list_add(&ev->loglevel_list,
					&loglevel->events);
			}
		}
	}
}

/*
 * Add the loglevel to the loglevel hash table. Must be called with
 * ust lock held.
 */
struct session_loglevel *add_loglevel(const char *name,
	struct ltt_channel *chan,
	struct lttng_ust_event *event_param)
{
	struct cds_hlist_head *head;
	struct cds_hlist_node *node;
	struct loglevel_entry *e;
	struct session_loglevel *sl;
	size_t name_len = strlen(name) + 1;
	uint32_t hash = jhash(name, name_len-1, 0);
	int found = 0;

	/* loglevel entry */
	head = &loglevel_table[hash & (LOGLEVEL_TABLE_SIZE - 1)];
	cds_hlist_for_each_entry(e, node, head, hlist) {
		if (!strcmp(name, e->name)) {
			found = 1;
			break;
		}
	}

	if (!found) {
		/*
		 * Using zmalloc here to allocate a variable length element. Could
		 * cause some memory fragmentation if overused.
		 */
		e = zmalloc(sizeof(struct loglevel_entry) + name_len);
		if (!e)
			return ERR_PTR(-ENOMEM);
		memcpy(&e->name[0], name, name_len);
		cds_hlist_add_head(&e->hlist, head);
		CDS_INIT_LIST_HEAD(&e->session_list);
	}

	/* session loglevel */
	cds_list_for_each_entry(sl, &e->session_list, session_list) {
		if (chan == sl->chan) {
			DBG("loglevel %s busy for this channel", name);
			return ERR_PTR(-EEXIST);	/* Already there */
		}
	}
	sl = zmalloc(sizeof(struct session_loglevel));
	if (!sl)
		return ERR_PTR(-ENOMEM);
	sl->chan = chan;
	sl->enabled = 1;
	memcpy(&sl->event_param, event_param, sizeof(sl->event_param));
	sl->event_param.instrumentation = LTTNG_UST_TRACEPOINT;
	CDS_INIT_LIST_HEAD(&sl->events);
	cds_list_add(&sl->list, &chan->session->loglevels);
	cds_list_add(&sl->session_list, &e->session_list);
	sl->entry = e;
	_probes_create_loglevel_events(e, sl);
	return sl;
}

/*
 * Remove the loglevel from the loglevel hash table. Must be called with
 * ust_lock held. Only called at session teardown.
 */
void _remove_loglevel(struct session_loglevel *loglevel)
{
	struct ltt_event *ev, *tmp;

	/*
	 * Just remove the events owned (for enable/disable) by this
	 * loglevel from the list. The session teardown will take care
	 * of freeing the event memory.
	 */
	cds_list_for_each_entry_safe(ev, tmp, &loglevel->events, list) {
		cds_list_del(&ev->list);
	}
	cds_list_del(&loglevel->session_list);
	cds_list_del(&loglevel->list);
	if (cds_list_empty(&loglevel->entry->session_list)) {
		cds_hlist_del(&loglevel->entry->hlist);
		free(loglevel->entry);
	}
	free(loglevel);
}

int ltt_loglevel_enable(struct session_loglevel *loglevel)
{
	struct ltt_event *ev;
	int ret;

	if (loglevel->enabled)
		return -EEXIST;
	cds_list_for_each_entry(ev, &loglevel->events, list) {
		ret = ltt_event_enable(ev);
		if (ret) {
			DBG("Error: enable error.\n");
			return ret;
		}
	}
	loglevel->enabled = 1;
	return 0;
}

int ltt_loglevel_disable(struct session_loglevel *loglevel)
{
	struct ltt_event *ev;
	int ret;

	if (!loglevel->enabled)
		return -EEXIST;
	cds_list_for_each_entry(ev, &loglevel->events, list) {
		ret = ltt_event_disable(ev);
		if (ret) {
			DBG("Error: disable error.\n");
			return ret;
		}
	}
	loglevel->enabled = 0;
	return 0;
}
Commit	Line	Data
ce5aef0b MD	1	/*
	2	* ltt-probes.c
	3	*
	4	* Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	*
	6	* Holds LTTng probes registry.
	7	*
	8	* Dual LGPL v2.1/GPL v2 license.
	9	*/
	10
8d8a24c8 MD	11	#include <string.h>
	12	#include <errno.h>
	13	#include <urcu/list.h>
1f18504e	14	#include <urcu/hlist.h>
4318ae1b	15	#include <lttng/ust-events.h>
a3bb4b27	16	#include <assert.h>
c8fcf224	17	#include <helper.h>
ce5aef0b	18
8165c8da	19	#include "ltt-tracer-core.h"
1f18504e MD	20	#include "jhash.h"
1f18504e MD	21	#include "error.h"
8165c8da MD	22
8165c8da MD	23	/*
17dfb34b	24	* probe list is protected by ust_lock()/ust_unlock().
8165c8da	25	*/
8d8a24c8	26	static CDS_LIST_HEAD(probe_list);
ce5aef0b	27
1f18504e MD	28	/*
	29	* Loglevel hash table, containing the active loglevels.
	30	* Protected by ust lock.
	31	*/
	32	#define LOGLEVEL_HASH_BITS 6
	33	#define LOGLEVEL_TABLE_SIZE (1 << LOGLEVEL_HASH_BITS)
	34	static struct cds_hlist_head loglevel_table[LOGLEVEL_TABLE_SIZE];
	35
df854e41 MD	36	static
	37	const struct lttng_probe_desc find_provider(const char provider)
	38	{
	39	struct lttng_probe_desc *iter;
	40
	41	cds_list_for_each_entry(iter, &probe_list, head) {
	42	if (!strcmp(iter->provider, provider))
	43	return iter;
	44	}
	45	return NULL;
	46	}
	47
ce5aef0b MD	48	static
	49	const struct lttng_event_desc find_event(const char name)
	50	{
	51	struct lttng_probe_desc *probe_desc;
	52	int i;
	53
8d8a24c8	54	cds_list_for_each_entry(probe_desc, &probe_list, head) {
ce5aef0b	55	for (i = 0; i < probe_desc->nr_events; i++) {
df854e41 MD	56	if (!strcmp(probe_desc->event_desc[i]->name, name))
df854e41 MD	57	return probe_desc->event_desc[i];
ce5aef0b MD	58	}
	59	}
	60	return NULL;
	61	}
	62
	63	int ltt_probe_register(struct lttng_probe_desc *desc)
	64	{
df854e41	65	struct lttng_probe_desc *iter;
ce5aef0b MD	66	int ret = 0;
	67	int i;
	68
17dfb34b	69	ust_lock();
df854e41 MD	70	if (find_provider(desc->provider)) {
	71	ret = -EEXIST;
	72	goto end;
	73	}
ce5aef0b MD	74	/*
	75	* TODO: This is O(N^2). Turn into a hash table when probe registration
	76	* overhead becomes an issue.
	77	*/
	78	for (i = 0; i < desc->nr_events; i++) {
df854e41	79	if (find_event(desc->event_desc[i]->name)) {
ce5aef0b MD	80	ret = -EEXIST;
	81	goto end;
	82	}
	83	}
df854e41 MD	84
	85	/*
	86	* We sort the providers by struct lttng_probe_desc pointer
	87	* address.
	88	*/
	89	cds_list_for_each_entry_reverse(iter, &probe_list, head) {
	90	BUG_ON(iter == desc); /* Should never be in the list twice */
	91	if (iter < desc) {
	92	/* We belong to the location right after iter. */
	93	cds_list_add(&desc->head, &iter->head);
	94	goto desc_added;
	95	}
	96	}
	97	/* We should be added at the head of the list */
8d8a24c8	98	cds_list_add(&desc->head, &probe_list);
df854e41	99	desc_added:
8165c8da MD	100
	101	/*
	102	* fix the events awaiting probe load.
	103	*/
	104	for (i = 0; i < desc->nr_events; i++) {
df854e41	105	ret = pending_probe_fix_events(desc->event_desc[i]);
8165c8da MD	106	assert(!ret);
8165c8da MD	107	}
ce5aef0b	108	end:
17dfb34b	109	ust_unlock();
ce5aef0b MD	110	return ret;
ce5aef0b MD	111	}
ce5aef0b MD	112
	113	void ltt_probe_unregister(struct lttng_probe_desc *desc)
	114	{
17dfb34b	115	ust_lock();
8d8a24c8	116	cds_list_del(&desc->head);
17dfb34b	117	ust_unlock();
ce5aef0b	118	}
ce5aef0b	119
8165c8da MD	120	/*
	121	* called with UST lock held.
	122	*/
ce5aef0b MD	123	const struct lttng_event_desc ltt_event_get(const char name)
	124	{
	125	const struct lttng_event_desc *event;
ce5aef0b	126
ce5aef0b	127	event = find_event(name);
ce5aef0b MD	128	if (!event)
ce5aef0b MD	129	return NULL;
ce5aef0b MD	130	return event;
ce5aef0b MD	131	}
ce5aef0b MD	132
	133	void ltt_event_put(const struct lttng_event_desc *event)
	134	{
ce5aef0b	135	}
c8fcf224 MD	136
	137	void ltt_probes_prune_event_list(struct lttng_ust_tracepoint_list *list)
	138	{
	139	struct tp_list_entry list_entry, tmp;
	140
	141	cds_list_for_each_entry_safe(list_entry, tmp, &list->head, head) {
	142	cds_list_del(&list_entry->head);
	143	free(list_entry);
	144	}
	145	}
	146
	147	/*
	148	* called with UST lock held.
	149	*/
	150	int ltt_probes_get_event_list(struct lttng_ust_tracepoint_list *list)
	151	{
	152	struct lttng_probe_desc *probe_desc;
	153	int i;
	154
	155	CDS_INIT_LIST_HEAD(&list->head);
	156	cds_list_for_each_entry(probe_desc, &probe_list, head) {
	157	for (i = 0; i < probe_desc->nr_events; i++) {
	158	struct tp_list_entry *list_entry;
	159
	160	list_entry = zmalloc(sizeof(*list_entry));
	161	if (!list_entry)
	162	goto err_nomem;
	163	cds_list_add(&list_entry->head, &list->head);
	164	strncpy(list_entry->tp.name,
	165	probe_desc->event_desc[i]->name,
	166	LTTNG_UST_SYM_NAME_LEN);
	167	list_entry->tp.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
	168	if (!probe_desc->event_desc[i]->loglevel) {
	169	list_entry->tp.loglevel[0] = '\0';
	170	list_entry->tp.loglevel_value = 0;
	171	} else {
	172	strncpy(list_entry->tp.loglevel,
	173	(*probe_desc->event_desc[i]->loglevel)->identifier,
	174	LTTNG_UST_SYM_NAME_LEN);
	175	list_entry->tp.loglevel[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
	176	list_entry->tp.loglevel_value =
	177	(*probe_desc->event_desc[i]->loglevel)->value;
	178	}
	179	}
	180	}
	181	if (cds_list_empty(&list->head))
	182	list->iter = NULL;
	183	else
	184	list->iter =
	185	cds_list_first_entry(&list->head, struct tp_list_entry, head);
	186	return 0;
	187
	188	err_nomem:
	189	ltt_probes_prune_event_list(list);
	190	return -ENOMEM;
	191	}
	192
	193	/*
	194	* Return current iteration position, advance internal iterator to next.
	195	* Return NULL if end of list.
	196	*/
	197	struct lttng_ust_tracepoint_iter *
	198	lttng_ust_tracepoint_list_get_iter_next(struct lttng_ust_tracepoint_list *list)
	199	{
200	struct tp_list_entry *entry;
201
202	if (!list->iter)
203	return NULL;
204	entry = list->iter;
205	if (entry->head.next == &list->head)
206	list->iter = NULL;
207	else
208	list->iter = cds_list_entry(entry->head.next,
209	struct tp_list_entry, head);
210	return &entry->tp;
211	}
1f18504e MD	212
	213	/*
	214	* Get loglevel if the loglevel is present in the loglevel hash table.
	215	* Must be called with ust lock held.
	216	* Returns NULL if not present.
	217	*/
	218	struct loglevel_entry get_loglevel(const char name)
	219	{
	220	struct cds_hlist_head *head;
	221	struct cds_hlist_node *node;
	222	struct loglevel_entry *e;
	223	uint32_t hash = jhash(name, strlen(name), 0);
	224
	225	head = &loglevel_table[hash & (LOGLEVEL_TABLE_SIZE - 1)];
	226	cds_hlist_for_each_entry(e, node, head, hlist) {
	227	if (!strcmp(name, e->name))
	228	return e;
	229	}
	230	return NULL;
	231	}
	232
	233	/*
	234	* marshall all probes/all events and create those that fit the
	235	* loglevel. Add them to the events list as created.
	236	*/
	237	static
574a6217 MD	238	void _probes_create_loglevel_events(struct loglevel_entry *entry,
574a6217 MD	239	struct session_loglevel *loglevel)
1f18504e MD	240	{
1f18504e MD	241	struct lttng_probe_desc *probe_desc;
7ee3cc56	242	struct lttng_ust_event event_param;
1f18504e MD	243	int i;
	244
	245	cds_list_for_each_entry(probe_desc, &probe_list, head) {
	246	for (i = 0; i < probe_desc->nr_events; i++) {
	247	const struct tracepoint_loglevel_entry *ev_ll;
7ee3cc56	248	const struct lttng_event_desc *event_desc;
1f18504e	249
7ee3cc56 MD	250	event_desc = probe_desc->event_desc[i];
7ee3cc56 MD	251	if (!(event_desc->loglevel))
1f18504e	252	continue;
7ee3cc56	253	ev_ll = *event_desc->loglevel;
574a6217	254	if (!strcmp(ev_ll->identifier, entry->name)) {
1f18504e MD	255	struct ltt_event *ev;
	256	int ret;
	257
7ee3cc56 MD	258	memcpy(&event_param, &loglevel->event_param,
	259	sizeof(event_param));
	260	memcpy(event_param.name,
	261	event_desc->name,
	262	sizeof(event_param.name));
1f18504e MD	263	/* create event */
1f18504e MD	264	ret = ltt_event_create(loglevel->chan,
7ee3cc56	265	&event_param, NULL,
1f18504e	266	&ev);
7ee3cc56 MD	267	if (ret) {
7ee3cc56 MD	268	DBG("Error creating event");
1f18504e	269	continue;
7ee3cc56	270	}
1f18504e MD	271	cds_list_add(&ev->loglevel_list,
	272	&loglevel->events);
	273	}
1f18504e MD	274	}
	275	}
	276	}
	277
	278	/*
	279	* Add the loglevel to the loglevel hash table. Must be called with
	280	* ust lock held.
	281	*/
574a6217	282	struct session_loglevel add_loglevel(const char name,
1f18504e MD	283	struct ltt_channel *chan,
	284	struct lttng_ust_event *event_param)
	285	{
	286	struct cds_hlist_head *head;
	287	struct cds_hlist_node *node;
	288	struct loglevel_entry *e;
574a6217	289	struct session_loglevel *sl;
1f18504e MD	290	size_t name_len = strlen(name) + 1;
1f18504e MD	291	uint32_t hash = jhash(name, name_len-1, 0);
574a6217	292	int found = 0;
1f18504e	293
574a6217	294	/* loglevel entry */
1f18504e MD	295	head = &loglevel_table[hash & (LOGLEVEL_TABLE_SIZE - 1)];
	296	cds_hlist_for_each_entry(e, node, head, hlist) {
	297	if (!strcmp(name, e->name)) {
574a6217 MD	298	found = 1;
	299	break;
	300	}
	301	}
	302
	303	if (!found) {
	304	/*
	305	* Using zmalloc here to allocate a variable length element. Could
	306	* cause some memory fragmentation if overused.
	307	*/
	308	e = zmalloc(sizeof(struct loglevel_entry) + name_len);
	309	if (!e)
	310	return ERR_PTR(-ENOMEM);
	311	memcpy(&e->name[0], name, name_len);
	312	cds_hlist_add_head(&e->hlist, head);
d5201d38	313	CDS_INIT_LIST_HEAD(&e->session_list);
574a6217 MD	314	}
	315
	316	/* session loglevel */
	317	cds_list_for_each_entry(sl, &e->session_list, session_list) {
	318	if (chan == sl->chan) {
	319	DBG("loglevel %s busy for this channel", name);
1f18504e MD	320	return ERR_PTR(-EEXIST); /* Already there */
	321	}
	322	}
574a6217 MD	323	sl = zmalloc(sizeof(struct session_loglevel));
574a6217 MD	324	if (!sl)
1f18504e	325	return ERR_PTR(-ENOMEM);
574a6217 MD	326	sl->chan = chan;
	327	sl->enabled = 1;
	328	memcpy(&sl->event_param, event_param, sizeof(sl->event_param));
d5201d38	329	sl->event_param.instrumentation = LTTNG_UST_TRACEPOINT;
574a6217 MD	330	CDS_INIT_LIST_HEAD(&sl->events);
	331	cds_list_add(&sl->list, &chan->session->loglevels);
	332	cds_list_add(&sl->session_list, &e->session_list);
2981744d	333	sl->entry = e;
574a6217 MD	334	_probes_create_loglevel_events(e, sl);
574a6217 MD	335	return sl;
1f18504e MD	336	}
	337
	338	/*
	339	* Remove the loglevel from the loglevel hash table. Must be called with
	340	* ust_lock held. Only called at session teardown.
	341	*/
574a6217	342	void _remove_loglevel(struct session_loglevel *loglevel)
1f18504e MD	343	{
	344	struct ltt_event ev, tmp;
	345
	346	/*
	347	* Just remove the events owned (for enable/disable) by this
	348	* loglevel from the list. The session teardown will take care
	349	* of freeing the event memory.
	350	*/
	351	cds_list_for_each_entry_safe(ev, tmp, &loglevel->events, list) {
	352	cds_list_del(&ev->list);
	353	}
574a6217	354	cds_list_del(&loglevel->session_list);
1f18504e	355	cds_list_del(&loglevel->list);
574a6217 MD	356	if (cds_list_empty(&loglevel->entry->session_list)) {
	357	cds_hlist_del(&loglevel->entry->hlist);
	358	free(loglevel->entry);
	359	}
1f18504e MD	360	free(loglevel);
	361	}
	362
574a6217	363	int ltt_loglevel_enable(struct session_loglevel *loglevel)
1f18504e MD	364	{
	365	struct ltt_event *ev;
	366	int ret;
	367
	368	if (loglevel->enabled)
	369	return -EEXIST;
	370	cds_list_for_each_entry(ev, &loglevel->events, list) {
	371	ret = ltt_event_enable(ev);
	372	if (ret) {
	373	DBG("Error: enable error.\n");
	374	return ret;
	375	}
	376	}
	377	loglevel->enabled = 1;
	378	return 0;
	379	}
	380
574a6217	381	int ltt_loglevel_disable(struct session_loglevel *loglevel)
1f18504e MD	382	{
	383	struct ltt_event *ev;
	384	int ret;
	385
	386	if (!loglevel->enabled)
	387	return -EEXIST;
	388	cds_list_for_each_entry(ev, &loglevel->events, list) {
	389	ret = ltt_event_disable(ev);
	390	if (ret) {
	391	DBG("Error: disable error.\n");
	392	return ret;
	393	}
	394	}
	395	loglevel->enabled = 0;
	396	return 0;
	397	}