[lttng-modules.git] / lttng-ring-buffer-metadata-client.h

/*
 * lttng-ring-buffer-client.h
 *
 * LTTng lib ring buffer client template.
 *
 * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; only
 * version 2.1 of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <linux/module.h>
#include <linux/types.h>
#include <wrapper/vmalloc.h>	/* for wrapper_vmalloc_sync_all() */
#include <lttng-events.h>
#include <lttng-tracer.h>

static struct lttng_transport lttng_relay_transport;

struct metadata_packet_header {
	uint32_t magic;			/* 0x75D11D57 */
	uint8_t  uuid[16];		/* Unique Universal Identifier */
	uint32_t checksum;		/* 0 if unused */
	uint32_t content_size;		/* in bits */
	uint32_t packet_size;		/* in bits */
	uint8_t  compression_scheme;	/* 0 if unused */
	uint8_t  encryption_scheme;	/* 0 if unused */
	uint8_t  checksum_scheme;	/* 0 if unused */
	uint8_t  major;			/* CTF spec major version number */
	uint8_t  minor;			/* CTF spec minor version number */
	uint8_t  header_end[0];
};

struct metadata_record_header {
	uint8_t header_end[0];		/* End of header */
};

static const struct lib_ring_buffer_config client_config;

static inline
u64 lib_ring_buffer_clock_read(struct channel *chan)
{
	return 0;
}

static inline
size_t record_header_size(const struct lib_ring_buffer_config *config,
				 struct channel *chan, size_t offset,
				 size_t *pre_header_padding,
				 struct lib_ring_buffer_ctx *ctx,
				 void *client_ctx)
{
	return 0;
}

#include <wrapper/ringbuffer/api.h>

static u64 client_ring_buffer_clock_read(struct channel *chan)
{
	return 0;
}

static
size_t client_record_header_size(const struct lib_ring_buffer_config *config,
				 struct channel *chan, size_t offset,
				 size_t *pre_header_padding,
				 struct lib_ring_buffer_ctx *ctx,
				 void *client_ctx)
{
	return 0;
}

/**
 * client_packet_header_size - called on buffer-switch to a new sub-buffer
 *
 * Return header size without padding after the structure. Don't use packed
 * structure because gcc generates inefficient code on some architectures
 * (powerpc, mips..)
 */
static size_t client_packet_header_size(void)
{
	return offsetof(struct metadata_packet_header, header_end);
}

static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
				unsigned int subbuf_idx)
{
	struct channel *chan = buf->backend.chan;
	struct metadata_packet_header *header =
		(struct metadata_packet_header *)
			lib_ring_buffer_offset_address(&buf->backend,
				subbuf_idx * chan->backend.subbuf_size);
	struct lttng_metadata_cache *metadata_cache =
		channel_get_private(chan);

	header->magic = TSDL_MAGIC_NUMBER;
	memcpy(header->uuid, metadata_cache->uuid.b,
		sizeof(metadata_cache->uuid));
	header->checksum = 0;		/* 0 if unused */
	header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
	header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
	header->compression_scheme = 0;	/* 0 if unused */
	header->encryption_scheme = 0;	/* 0 if unused */
	header->checksum_scheme = 0;	/* 0 if unused */
	header->major = CTF_SPEC_MAJOR;
	header->minor = CTF_SPEC_MINOR;
}

/*
 * offset is assumed to never be 0 here : never deliver a completely empty
 * subbuffer. data_size is between 1 and subbuf_size.
 */
static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
			      unsigned int subbuf_idx, unsigned long data_size)
{
	struct channel *chan = buf->backend.chan;
	struct metadata_packet_header *header =
		(struct metadata_packet_header *)
			lib_ring_buffer_offset_address(&buf->backend,
				subbuf_idx * chan->backend.subbuf_size);
	unsigned long records_lost = 0;

	header->content_size = data_size * CHAR_BIT;		/* in bits */
	header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
	/*
	 * We do not care about the records lost count, because the metadata
	 * channel waits and retry.
	 */
	(void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
	records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
	records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
	WARN_ON_ONCE(records_lost != 0);
}

static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
				int cpu, const char *name)
{
	return 0;
}

static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
{
}

static int client_timestamp_begin(const struct lib_ring_buffer_config *config,
		struct lib_ring_buffer *buf, uint64_t *timestamp_begin)
{
	return -ENOSYS;
}

static int client_timestamp_end(const struct lib_ring_buffer_config *config,
			struct lib_ring_buffer *bufb,
			uint64_t *timestamp_end)
{
	return -ENOSYS;
}

static int client_events_discarded(const struct lib_ring_buffer_config *config,
			struct lib_ring_buffer *bufb,
			uint64_t *events_discarded)
{
	return -ENOSYS;
}

static int client_current_timestamp(const struct lib_ring_buffer_config *config,
		struct lib_ring_buffer *bufb,
		uint64_t *ts)
{
	return -ENOSYS;
}

static int client_content_size(const struct lib_ring_buffer_config *config,
			struct lib_ring_buffer *bufb,
			uint64_t *content_size)
{
	return -ENOSYS;
}

static int client_packet_size(const struct lib_ring_buffer_config *config,
			struct lib_ring_buffer *bufb,
			uint64_t *packet_size)
{
	return -ENOSYS;
}

static int client_stream_id(const struct lib_ring_buffer_config *config,
			struct lib_ring_buffer *bufb,
			uint64_t *stream_id)
{
	return -ENOSYS;
}

static int client_sequence_number(const struct lib_ring_buffer_config *config,
			struct lib_ring_buffer *bufb,
			uint64_t *seq)
{
	return -ENOSYS;
}

static
int client_instance_id(const struct lib_ring_buffer_config *config,
		struct lib_ring_buffer *bufb,
		uint64_t *id)
{
	return -ENOSYS;
}

static const struct lib_ring_buffer_config client_config = {
	.cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
	.cb.record_header_size = client_record_header_size,
	.cb.subbuffer_header_size = client_packet_header_size,
	.cb.buffer_begin = client_buffer_begin,
	.cb.buffer_end = client_buffer_end,
	.cb.buffer_create = client_buffer_create,
	.cb.buffer_finalize = client_buffer_finalize,

	.tsc_bits = 0,
	.alloc = RING_BUFFER_ALLOC_GLOBAL,
	.sync = RING_BUFFER_SYNC_GLOBAL,
	.mode = RING_BUFFER_MODE_TEMPLATE,
	.backend = RING_BUFFER_PAGE,
	.output = RING_BUFFER_OUTPUT_TEMPLATE,
	.oops = RING_BUFFER_OOPS_CONSISTENCY,
	.ipi = RING_BUFFER_IPI_BARRIER,
	.wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
};

static
void release_priv_ops(void *priv_ops)
{
	module_put(THIS_MODULE);
}

static
void lttng_channel_destroy(struct channel *chan)
{
	channel_destroy(chan);
}

static
struct channel *_channel_create(const char *name,
				struct lttng_channel *lttng_chan, void *buf_addr,
				size_t subbuf_size, size_t num_subbuf,
				unsigned int switch_timer_interval,
				unsigned int read_timer_interval)
{
	struct channel *chan;

	chan = channel_create(&client_config, name,
			      lttng_chan->session->metadata_cache, buf_addr,
			      subbuf_size, num_subbuf, switch_timer_interval,
			      read_timer_interval);
	if (chan) {
		/*
		 * Ensure this module is not unloaded before we finish
		 * using lttng_relay_transport.ops.
		 */
		if (!try_module_get(THIS_MODULE)) {
			printk(KERN_WARNING "LTT : Can't lock transport module.\n");
			goto error;
		}
		chan->backend.priv_ops = &lttng_relay_transport.ops;
		chan->backend.release_priv_ops = release_priv_ops;
	}
	return chan;

error:
	lttng_channel_destroy(chan);
	return NULL;
}

static
struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
{
	struct lib_ring_buffer *buf;

	buf = channel_get_ring_buffer(&client_config, chan, 0);
	if (!lib_ring_buffer_open_read(buf))
		return buf;
	return NULL;
}

static
int lttng_buffer_has_read_closed_stream(struct channel *chan)
{
	struct lib_ring_buffer *buf;
	int cpu;

	for_each_channel_cpu(cpu, chan) {
		buf = channel_get_ring_buffer(&client_config, chan, cpu);
		if (!atomic_long_read(&buf->active_readers))
			return 1;
	}
	return 0;
}

static
void lttng_buffer_read_close(struct lib_ring_buffer *buf)
{
	lib_ring_buffer_release_read(buf);
}

static
int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
{
	int ret;

	ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
	if (ret)
		return ret;
	lib_ring_buffer_backend_get_pages(&client_config, ctx,
			&ctx->backend_pages);
	return 0;

}

static
void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
{
	lib_ring_buffer_commit(&client_config, ctx);
}

static
void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
		     size_t len)
{
	lib_ring_buffer_write(&client_config, ctx, src, len);
}

static
void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
			       const void __user *src, size_t len)
{
	lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
}

static
void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
		int c, size_t len)
{
	lib_ring_buffer_memset(&client_config, ctx, c, len);
}

static
void lttng_event_strcpy(struct lib_ring_buffer_ctx *ctx, const char *src,
		size_t len)
{
	lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
}

static
size_t lttng_packet_avail_size(struct channel *chan)
			     
{
	unsigned long o_begin;
	struct lib_ring_buffer *buf;

	buf = chan->backend.buf;	/* Only for global buffer ! */
	o_begin = v_read(&client_config, &buf->offset);
	if (subbuf_offset(o_begin, chan) != 0) {
		return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
	} else {
		return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
			- sizeof(struct metadata_packet_header);
	}
}

static
wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
{
	struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
					chan, cpu);
	return &buf->write_wait;
}

static
wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
{
	return &chan->hp_wait;
}

static
int lttng_is_finalized(struct channel *chan)
{
	return lib_ring_buffer_channel_is_finalized(chan);
}

static
int lttng_is_disabled(struct channel *chan)
{
	return lib_ring_buffer_channel_is_disabled(chan);
}

static struct lttng_transport lttng_relay_transport = {
	.name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
	.owner = THIS_MODULE,
	.ops = {
		.channel_create = _channel_create,
		.channel_destroy = lttng_channel_destroy,
		.buffer_read_open = lttng_buffer_read_open,
		.buffer_has_read_closed_stream =
			lttng_buffer_has_read_closed_stream,
		.buffer_read_close = lttng_buffer_read_close,
		.event_reserve = lttng_event_reserve,
		.event_commit = lttng_event_commit,
		.event_write_from_user = lttng_event_write_from_user,
		.event_memset = lttng_event_memset,
		.event_write = lttng_event_write,
		.event_strcpy = lttng_event_strcpy,
		.packet_avail_size = lttng_packet_avail_size,
		.get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
		.get_hp_wait_queue = lttng_get_hp_wait_queue,
		.is_finalized = lttng_is_finalized,
		.is_disabled = lttng_is_disabled,
		.timestamp_begin = client_timestamp_begin,
		.timestamp_end = client_timestamp_end,
		.events_discarded = client_events_discarded,
		.content_size = client_content_size,
		.packet_size = client_packet_size,
		.stream_id = client_stream_id,
		.current_timestamp = client_current_timestamp,
		.sequence_number = client_sequence_number,
		.instance_id = client_instance_id,
	},
};

static int __init lttng_ring_buffer_client_init(void)
{
	/*
	 * This vmalloc sync all also takes care of the lib ring buffer
	 * vmalloc'd module pages when it is built as a module into LTTng.
	 */
	wrapper_vmalloc_sync_all();
	lttng_transport_register(&lttng_relay_transport);
	return 0;
}

module_init(lttng_ring_buffer_client_init);

static void __exit lttng_ring_buffer_client_exit(void)
{
	lttng_transport_unregister(&lttng_relay_transport);
}

module_exit(lttng_ring_buffer_client_exit);

MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
		   " client");
Commit	Line	Data
	1	/*
	2	* lttng-ring-buffer-client.h
	3	*
	4	* LTTng lib ring buffer client template.
	5	*
	6	* Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	7	*
	8	* This library is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; only
	11	* version 2.1 of the License.
	12	*
	13	* This library is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with this library; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	21	*/
	22
	23	#include <linux/module.h>
	24	#include <linux/types.h>
	25	#include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_all() */
	26	#include <lttng-events.h>
	27	#include <lttng-tracer.h>
	28
	29	static struct lttng_transport lttng_relay_transport;
	30
	31	struct metadata_packet_header {
	32	uint32_t magic; /* 0x75D11D57 */
	33	uint8_t uuid[16]; /* Unique Universal Identifier */
	34	uint32_t checksum; /* 0 if unused */
	35	uint32_t content_size; /* in bits */
	36	uint32_t packet_size; /* in bits */
	37	uint8_t compression_scheme; /* 0 if unused */
	38	uint8_t encryption_scheme; /* 0 if unused */
	39	uint8_t checksum_scheme; /* 0 if unused */
	40	uint8_t major; /* CTF spec major version number */
	41	uint8_t minor; /* CTF spec minor version number */
	42	uint8_t header_end[0];
	43	};
	44
	45	struct metadata_record_header {
	46	uint8_t header_end[0]; /* End of header */
	47	};
	48
	49	static const struct lib_ring_buffer_config client_config;
	50
	51	static inline
	52	u64 lib_ring_buffer_clock_read(struct channel *chan)
	53	{
	54	return 0;
	55	}
	56
	57	static inline
	58	size_t record_header_size(const struct lib_ring_buffer_config *config,
	59	struct channel *chan, size_t offset,
	60	size_t *pre_header_padding,
	61	struct lib_ring_buffer_ctx *ctx,
	62	void *client_ctx)
	63	{
	64	return 0;
	65	}
	66
	67	#include <wrapper/ringbuffer/api.h>
	68
	69	static u64 client_ring_buffer_clock_read(struct channel *chan)
	70	{
	71	return 0;
	72	}
	73
	74	static
	75	size_t client_record_header_size(const struct lib_ring_buffer_config *config,
	76	struct channel *chan, size_t offset,
	77	size_t *pre_header_padding,
	78	struct lib_ring_buffer_ctx *ctx,
	79	void *client_ctx)
	80	{
	81	return 0;
	82	}
	83
	84	/**
	85	* client_packet_header_size - called on buffer-switch to a new sub-buffer
	86	*
	87	* Return header size without padding after the structure. Don't use packed
	88	* structure because gcc generates inefficient code on some architectures
	89	* (powerpc, mips..)
	90	*/
	91	static size_t client_packet_header_size(void)
	92	{
	93	return offsetof(struct metadata_packet_header, header_end);
	94	}
	95
	96	static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
	97	unsigned int subbuf_idx)
	98	{
	99	struct channel *chan = buf->backend.chan;
	100	struct metadata_packet_header *header =
	101	(struct metadata_packet_header *)
	102	lib_ring_buffer_offset_address(&buf->backend,
	103	subbuf_idx * chan->backend.subbuf_size);
	104	struct lttng_metadata_cache *metadata_cache =
	105	channel_get_private(chan);
	106
	107	header->magic = TSDL_MAGIC_NUMBER;
	108	memcpy(header->uuid, metadata_cache->uuid.b,
	109	sizeof(metadata_cache->uuid));
	110	header->checksum = 0; /* 0 if unused */
	111	header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
	112	header->packet_size = 0xFFFFFFFF; /* in bits, for debugging */
	113	header->compression_scheme = 0; /* 0 if unused */
	114	header->encryption_scheme = 0; /* 0 if unused */
	115	header->checksum_scheme = 0; /* 0 if unused */
	116	header->major = CTF_SPEC_MAJOR;
	117	header->minor = CTF_SPEC_MINOR;
	118	}
	119
	120	/*
	121	* offset is assumed to never be 0 here : never deliver a completely empty
	122	* subbuffer. data_size is between 1 and subbuf_size.
	123	*/
	124	static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
	125	unsigned int subbuf_idx, unsigned long data_size)
	126	{
	127	struct channel *chan = buf->backend.chan;
	128	struct metadata_packet_header *header =
	129	(struct metadata_packet_header *)
	130	lib_ring_buffer_offset_address(&buf->backend,
	131	subbuf_idx * chan->backend.subbuf_size);
	132	unsigned long records_lost = 0;
	133
	134	header->content_size = data_size * CHAR_BIT; /* in bits */
	135	header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
	136	/*
	137	* We do not care about the records lost count, because the metadata
	138	* channel waits and retry.
	139	*/
	140	(void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
	141	records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
	142	records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
	143	WARN_ON_ONCE(records_lost != 0);
	144	}
	145
	146	static int client_buffer_create(struct lib_ring_buffer buf, void priv,
	147	int cpu, const char *name)
	148	{
	149	return 0;
	150	}
	151
	152	static void client_buffer_finalize(struct lib_ring_buffer buf, void priv, int cpu)
	153	{
	154	}
	155
	156	static int client_timestamp_begin(const struct lib_ring_buffer_config *config,
	157	struct lib_ring_buffer buf, uint64_t timestamp_begin)
	158	{
	159	return -ENOSYS;
	160	}
	161
	162	static int client_timestamp_end(const struct lib_ring_buffer_config *config,
	163	struct lib_ring_buffer *bufb,
	164	uint64_t *timestamp_end)
	165	{
	166	return -ENOSYS;
	167	}
	168
	169	static int client_events_discarded(const struct lib_ring_buffer_config *config,
	170	struct lib_ring_buffer *bufb,
	171	uint64_t *events_discarded)
	172	{
	173	return -ENOSYS;
	174	}
	175
	176	static int client_current_timestamp(const struct lib_ring_buffer_config *config,
	177	struct lib_ring_buffer *bufb,
	178	uint64_t *ts)
	179	{
	180	return -ENOSYS;
	181	}
	182
	183	static int client_content_size(const struct lib_ring_buffer_config *config,
	184	struct lib_ring_buffer *bufb,
	185	uint64_t *content_size)
	186	{
	187	return -ENOSYS;
	188	}
	189
	190	static int client_packet_size(const struct lib_ring_buffer_config *config,
	191	struct lib_ring_buffer *bufb,
	192	uint64_t *packet_size)
	193	{
	194	return -ENOSYS;
	195	}
	196
	197	static int client_stream_id(const struct lib_ring_buffer_config *config,
	198	struct lib_ring_buffer *bufb,
	199	uint64_t *stream_id)
	200	{
	201	return -ENOSYS;
	202	}
	203
	204	static int client_sequence_number(const struct lib_ring_buffer_config *config,
	205	struct lib_ring_buffer *bufb,
	206	uint64_t *seq)
	207	{
	208	return -ENOSYS;
	209	}
	210
	211	static
	212	int client_instance_id(const struct lib_ring_buffer_config *config,
	213	struct lib_ring_buffer *bufb,
	214	uint64_t *id)
	215	{
	216	return -ENOSYS;
	217	}
	218
	219	static const struct lib_ring_buffer_config client_config = {
	220	.cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
	221	.cb.record_header_size = client_record_header_size,
	222	.cb.subbuffer_header_size = client_packet_header_size,
	223	.cb.buffer_begin = client_buffer_begin,
	224	.cb.buffer_end = client_buffer_end,
	225	.cb.buffer_create = client_buffer_create,
	226	.cb.buffer_finalize = client_buffer_finalize,
	227
	228	.tsc_bits = 0,
	229	.alloc = RING_BUFFER_ALLOC_GLOBAL,
	230	.sync = RING_BUFFER_SYNC_GLOBAL,
	231	.mode = RING_BUFFER_MODE_TEMPLATE,
	232	.backend = RING_BUFFER_PAGE,
	233	.output = RING_BUFFER_OUTPUT_TEMPLATE,
	234	.oops = RING_BUFFER_OOPS_CONSISTENCY,
	235	.ipi = RING_BUFFER_IPI_BARRIER,
	236	.wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
	237	};
	238
	239	static
	240	void release_priv_ops(void *priv_ops)
	241	{
	242	module_put(THIS_MODULE);
	243	}
	244
	245	static
	246	void lttng_channel_destroy(struct channel *chan)
	247	{
	248	channel_destroy(chan);
	249	}
	250
	251	static
	252	struct channel _channel_create(const char name,
	253	struct lttng_channel lttng_chan, void buf_addr,
	254	size_t subbuf_size, size_t num_subbuf,
	255	unsigned int switch_timer_interval,
	256	unsigned int read_timer_interval)
	257	{
	258	struct channel *chan;
	259
	260	chan = channel_create(&client_config, name,
	261	lttng_chan->session->metadata_cache, buf_addr,
	262	subbuf_size, num_subbuf, switch_timer_interval,
	263	read_timer_interval);
	264	if (chan) {
	265	/*
	266	* Ensure this module is not unloaded before we finish
	267	* using lttng_relay_transport.ops.
	268	*/
	269	if (!try_module_get(THIS_MODULE)) {
	270	printk(KERN_WARNING "LTT : Can't lock transport module.\n");
	271	goto error;
	272	}
	273	chan->backend.priv_ops = &lttng_relay_transport.ops;
	274	chan->backend.release_priv_ops = release_priv_ops;
	275	}
	276	return chan;
	277
	278	error:
	279	lttng_channel_destroy(chan);
	280	return NULL;
	281	}
	282
	283	static
	284	struct lib_ring_buffer lttng_buffer_read_open(struct channel chan)
	285	{
	286	struct lib_ring_buffer *buf;
	287
	288	buf = channel_get_ring_buffer(&client_config, chan, 0);
	289	if (!lib_ring_buffer_open_read(buf))
	290	return buf;
	291	return NULL;
	292	}
	293
	294	static
	295	int lttng_buffer_has_read_closed_stream(struct channel *chan)
	296	{
	297	struct lib_ring_buffer *buf;
	298	int cpu;
	299
	300	for_each_channel_cpu(cpu, chan) {
	301	buf = channel_get_ring_buffer(&client_config, chan, cpu);
	302	if (!atomic_long_read(&buf->active_readers))
	303	return 1;
	304	}
	305	return 0;
	306	}
	307
	308	static
	309	void lttng_buffer_read_close(struct lib_ring_buffer *buf)
	310	{
	311	lib_ring_buffer_release_read(buf);
	312	}
	313
	314	static
	315	int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
	316	{
	317	int ret;
	318
	319	ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
	320	if (ret)
	321	return ret;
	322	lib_ring_buffer_backend_get_pages(&client_config, ctx,
	323	&ctx->backend_pages);
	324	return 0;
	325
	326	}
	327
	328	static
	329	void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
	330	{
	331	lib_ring_buffer_commit(&client_config, ctx);
	332	}
	333
	334	static
	335	void lttng_event_write(struct lib_ring_buffer_ctx ctx, const void src,
	336	size_t len)
	337	{
	338	lib_ring_buffer_write(&client_config, ctx, src, len);
	339	}
	340
	341	static
	342	void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
	343	const void __user *src, size_t len)
	344	{
	345	lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
	346	}
	347
	348	static
	349	void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
	350	int c, size_t len)
	351	{
	352	lib_ring_buffer_memset(&client_config, ctx, c, len);
	353	}
	354
	355	static
	356	void lttng_event_strcpy(struct lib_ring_buffer_ctx ctx, const char src,
	357	size_t len)
	358	{
	359	lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
	360	}
	361
	362	static
	363	size_t lttng_packet_avail_size(struct channel *chan)
	364
	365	{
	366	unsigned long o_begin;
	367	struct lib_ring_buffer *buf;
	368
	369	buf = chan->backend.buf; /* Only for global buffer ! */
	370	o_begin = v_read(&client_config, &buf->offset);
	371	if (subbuf_offset(o_begin, chan) != 0) {
	372	return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
	373	} else {
	374	return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
	375	- sizeof(struct metadata_packet_header);
	376	}
	377	}
	378
	379	static
	380	wait_queue_head_t lttng_get_writer_buf_wait_queue(struct channel chan, int cpu)
	381	{
	382	struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
	383	chan, cpu);
	384	return &buf->write_wait;
	385	}
	386
	387	static
	388	wait_queue_head_t lttng_get_hp_wait_queue(struct channel chan)
	389	{
	390	return &chan->hp_wait;
	391	}
	392
	393	static
	394	int lttng_is_finalized(struct channel *chan)
	395	{
	396	return lib_ring_buffer_channel_is_finalized(chan);
	397	}
	398
	399	static
	400	int lttng_is_disabled(struct channel *chan)
	401	{
	402	return lib_ring_buffer_channel_is_disabled(chan);
	403	}
	404
	405	static struct lttng_transport lttng_relay_transport = {
	406	.name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
	407	.owner = THIS_MODULE,
	408	.ops = {
	409	.channel_create = _channel_create,
	410	.channel_destroy = lttng_channel_destroy,
	411	.buffer_read_open = lttng_buffer_read_open,
	412	.buffer_has_read_closed_stream =
	413	lttng_buffer_has_read_closed_stream,
	414	.buffer_read_close = lttng_buffer_read_close,
	415	.event_reserve = lttng_event_reserve,
	416	.event_commit = lttng_event_commit,
	417	.event_write_from_user = lttng_event_write_from_user,
	418	.event_memset = lttng_event_memset,
	419	.event_write = lttng_event_write,
	420	.event_strcpy = lttng_event_strcpy,
	421	.packet_avail_size = lttng_packet_avail_size,
	422	.get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
	423	.get_hp_wait_queue = lttng_get_hp_wait_queue,
	424	.is_finalized = lttng_is_finalized,
	425	.is_disabled = lttng_is_disabled,
	426	.timestamp_begin = client_timestamp_begin,
	427	.timestamp_end = client_timestamp_end,
	428	.events_discarded = client_events_discarded,
	429	.content_size = client_content_size,
	430	.packet_size = client_packet_size,
	431	.stream_id = client_stream_id,
	432	.current_timestamp = client_current_timestamp,
	433	.sequence_number = client_sequence_number,
	434	.instance_id = client_instance_id,
	435	},
	436	};
	437
	438	static int __init lttng_ring_buffer_client_init(void)
	439	{
	440	/*
	441	* This vmalloc sync all also takes care of the lib ring buffer
	442	* vmalloc'd module pages when it is built as a module into LTTng.
	443	*/
	444	wrapper_vmalloc_sync_all();
	445	lttng_transport_register(&lttng_relay_transport);
	446	return 0;
	447	}
	448
	449	module_init(lttng_ring_buffer_client_init);
	450
	451	static void __exit lttng_ring_buffer_client_exit(void)
	452	{
	453	lttng_transport_unregister(&lttng_relay_transport);
	454	}
	455
	456	module_exit(lttng_ring_buffer_client_exit);
	457
	458	MODULE_LICENSE("GPL and additional rights");
	459	MODULE_AUTHOR("Mathieu Desnoyers");
	460	MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
	461	" client");