[lttng-modules.git] / ltt-events.c

/*
 * ltt-events.c
 *
 * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Holds LTTng per-session event registry.
 */

#include <linux/module.h>
#include "ltt-events.h"

static LIST_HEAD(sessions);
static DEFINE_MUTEX(sessions_mutex);
static struct kmem_cache *event_cache;

struct ltt_session *ltt_session_create(char *name)
{
	struct ltt_session *session;

	mutex_lock(&sessions_mutex);
	list_for_each_entry(session, &sessions, list)
		if (!strcmp(session->name, name))
			goto exist;
	session = kmalloc(sizeof(struct ltt_session) + strlen(name) + 1);
	if (!session)
		return NULL;
	strcpy(session->name, name);
	INIT_LIST_HEAD(&session->chan);
	list_add(&session->list, &sessions);
	mutex_unlock(&sessions_mutex);
	return session;

exist:
	mutex_unlock(&sessions_mutex);
	return NULL;
}

int ltt_session_destroy(struct ltt_session *session)
{
	struct ltt_channel *chan, *tmpchan;
	struct ltt_event *event, *tmpevent;

	mutex_lock(&sessions_mutex);
	list_for_each_entry_safe(event, tmpevent, &session->events, list)
		_ltt_event_destroy(event);
	list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
		_ltt_channel_destroy(chan);
	list_del(&session->list);
	mutex_unlock(&sessions_mutex);
	kfree(session);
}

struct ltt_channel *ltt_channel_create(struct ltt_session *session, char *name,
				       int overwrite, void *buf_addr,
				       size_t subbuf_size, size_t num_subbuf,
				       unsigned int switch_timer_interval,
				       unsigned int read_timer_interval)
{
	struct ltt_channel *chan;

	mutex_lock(&sessions_mutex);
	if (session->active)
		goto active;	/* Refuse to add channel to active session */
	list_for_each_entry(chan, &session->chan, list)
		if (!strcmp(chan->name, name))
			goto exist;
	chan = kmalloc(sizeof(struct ltt_channel) + strlen(name) + 1, GFP_KERNEL);
	if (!chan)
		return NULL;
	strcpy(chan->name, name);
	chan->session = session;

	/* TODO: create rb channel */
	list_add(&chan->list, &session->chan);
	mutex_unlock(&sessions_mutex);
	return chan;

exist:
active:
	mutex_unlock(&sessions_mutex);
	return NULL;
}

/*
 * Only used internally at session destruction.
 */
int _ltt_channel_destroy(struct ltt_channel *chan)
{
	list_del(&chan->list);
	kfree(chan);
}

/*
 * Supports event creation while tracing session is active.
 */
struct ltt_event *ltt_event_create(struct ltt_channel *chan, char *name,
				   void *filter)
{
	struct ltt_event *event;

	mutex_lock(&sessions_mutex);
	if (chan->free_event_id == -1UL)
		goto full;
	/*
	 * This is O(n^2) (for each event loop called at event creation).
	 * Might require a hash if we have lots of events.
	 */
	list_for_each_entry(event, &chan->session->events, list)
		if (!strcmp(event->name, name))
			goto exist;
	event = kmem_cache_zalloc(events_cache, GFP_KERNEL);
	if (!event)
		goto cache_error;
	event->name = kmalloc(strlen(name) + 1, GFP_KERNEL);
	if (!event->name)
		goto error;
	strcpy(event->name, name);
	event->chan = chan;
	event->filter = filter;
	event->id = chan->free_event_id++;
	mutex_unlock(&sessions_mutex);
	/* Populate ltt_event structure before tracepoint registration. */
	smp_wmb();
	/* TODO register to tracepoint */
	return event;

error:
	kmem_cache_free(event);
cache_error:
exist:
full:
	mutex_unlock(&sessions_mutex);
	return NULL;
}

/*
 * Only used internally at session destruction.
 */
int _ltt_event_destroy(struct ltt_event *event)
{
	/* TODO unregister from tracepoint */
	kfree(event->name);
	kmem_cache_free(event);
}

static int __init ltt_events_init(void)
{
	int ret;

	events_cache = KMEM_CACHE(ltt_event, 0);
	if (!events_cache)
		return -ENOMEM;

	/* TODO: show ABI to userspace */

	return 0;
}

static void __exit ltt_events_exit(void)
{
	struct ltt_session *session, *tmpsession;

	/* TODO: hide ABI from userspace, wait for callers to release refs. */

	list_for_each_entry_safe(session, tmpsession, &sessions, list)
		ltt_session_destroy(session);
	kmem_cache_destroy(events_cache);
}

MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
MODULE_DESCRIPTION("LTTng Events");
Commit	Line	Data
4e3c1b9b MD	1	/*
	2	* ltt-events.c
	3	*
	4	* Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	*
	6	* Holds LTTng per-session event registry.
	7	*/
	8
	9	#include <linux/module.h>
	10	#include "ltt-events.h"
	11
	12	static LIST_HEAD(sessions);
	13	static DEFINE_MUTEX(sessions_mutex);
	14	static struct kmem_cache *event_cache;
	15
	16	struct ltt_session ltt_session_create(char name)
	17	{
	18	struct ltt_session *session;
	19
	20	mutex_lock(&sessions_mutex);
	21	list_for_each_entry(session, &sessions, list)
	22	if (!strcmp(session->name, name))
	23	goto exist;
	24	session = kmalloc(sizeof(struct ltt_session) + strlen(name) + 1);
	25	if (!session)
	26	return NULL;
	27	strcpy(session->name, name);
	28	INIT_LIST_HEAD(&session->chan);
	29	list_add(&session->list, &sessions);
	30	mutex_unlock(&sessions_mutex);
	31	return session;
	32
	33	exist:
	34	mutex_unlock(&sessions_mutex);
	35	return NULL;
	36	}
	37
	38	int ltt_session_destroy(struct ltt_session *session)
	39	{
	40	struct ltt_channel chan, tmpchan;
	41	struct ltt_event event, tmpevent;
	42
	43	mutex_lock(&sessions_mutex);
	44	list_for_each_entry_safe(event, tmpevent, &session->events, list)
	45	_ltt_event_destroy(event);
	46	list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
	47	_ltt_channel_destroy(chan);
	48	list_del(&session->list);
	49	mutex_unlock(&sessions_mutex);
	50	kfree(session);
	51	}
	52
	53	struct ltt_channel ltt_channel_create(struct ltt_session session, char *name,
	54	int overwrite, void *buf_addr,
	55	size_t subbuf_size, size_t num_subbuf,
	56	unsigned int switch_timer_interval,
	57	unsigned int read_timer_interval)
	58	{
	59	struct ltt_channel *chan;
	60
	61	mutex_lock(&sessions_mutex);
e5382b6d MD	62	if (session->active)
e5382b6d MD	63	goto active; /* Refuse to add channel to active session */
4e3c1b9b MD	64	list_for_each_entry(chan, &session->chan, list)
	65	if (!strcmp(chan->name, name))
	66	goto exist;
	67	chan = kmalloc(sizeof(struct ltt_channel) + strlen(name) + 1, GFP_KERNEL);
	68	if (!chan)
	69	return NULL;
	70	strcpy(chan->name, name);
	71	chan->session = session;
	72
	73	/* TODO: create rb channel */
	74	list_add(&chan->list, &session->chan);
	75	mutex_unlock(&sessions_mutex);
	76	return chan;
	77
	78	exist:
e5382b6d	79	active:
4e3c1b9b MD	80	mutex_unlock(&sessions_mutex);
	81	return NULL;
	82	}
	83
	84	/*
	85	* Only used internally at session destruction.
	86	*/
	87	int _ltt_channel_destroy(struct ltt_channel *chan)
	88	{
	89	list_del(&chan->list);
	90	kfree(chan);
	91	}
	92
e5382b6d MD	93	/*
	94	* Supports event creation while tracing session is active.
	95	*/
4e3c1b9b MD	96	struct ltt_event ltt_event_create(struct ltt_channel chan, char *name,
	97	void *filter)
	98	{
	99	struct ltt_event *event;
	100
	101	mutex_lock(&sessions_mutex);
e5382b6d MD	102	if (chan->free_event_id == -1UL)
e5382b6d MD	103	goto full;
4e3c1b9b MD	104	/*
	105	* This is O(n^2) (for each event loop called at event creation).
	106	* Might require a hash if we have lots of events.
	107	*/
	108	list_for_each_entry(event, &chan->session->events, list)
	109	if (!strcmp(event->name, name))
	110	goto exist;
	111	event = kmem_cache_zalloc(events_cache, GFP_KERNEL);
	112	if (!event)
	113	goto cache_error;
	114	event->name = kmalloc(strlen(name) + 1, GFP_KERNEL);
	115	if (!event->name)
	116	goto error;
	117	strcpy(event->name, name);
	118	event->chan = chan;
	119	event->filter = filter;
e5382b6d	120	event->id = chan->free_event_id++;
4e3c1b9b	121	mutex_unlock(&sessions_mutex);
e5382b6d MD	122	/* Populate ltt_event structure before tracepoint registration. */
	123	smp_wmb();
	124	/* TODO register to tracepoint */
4e3c1b9b MD	125	return event;
	126
	127	error:
	128	kmem_cache_free(event);
	129	cache_error:
	130	exist:
e5382b6d	131	full:
4e3c1b9b MD	132	mutex_unlock(&sessions_mutex);
	133	return NULL;
	134	}
	135
	136	/*
	137	* Only used internally at session destruction.
	138	*/
	139	int _ltt_event_destroy(struct ltt_event *event)
	140	{
	141	/* TODO unregister from tracepoint */
	142	kfree(event->name);
	143	kmem_cache_free(event);
	144	}
	145
	146	static int __init ltt_events_init(void)
	147	{
	148	int ret;
	149
	150	events_cache = KMEM_CACHE(ltt_event, 0);
	151	if (!events_cache)
	152	return -ENOMEM;
92e94819 MD	153
	154	/* TODO: show ABI to userspace */
	155
4e3c1b9b MD	156	return 0;
	157	}
	158
	159	static void __exit ltt_events_exit(void)
	160	{
92e94819 MD	161	struct ltt_session session, tmpsession;
	162
	163	/* TODO: hide ABI from userspace, wait for callers to release refs. */
	164
	165	list_for_each_entry_safe(session, tmpsession, &sessions, list)
	166	ltt_session_destroy(session);
4e3c1b9b MD	167	kmem_cache_destroy(events_cache);
4e3c1b9b MD	168	}
92e94819 MD	169
	170	MODULE_LICENSE("GPL and additional rights");
	171	MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
	172	MODULE_DESCRIPTION("LTTng Events");