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

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 *
 * lttng-ring-buffer-client.h
 *
 * LTTng lib ring buffer client template.
 *
 * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <wrapper/vmalloc.h>	/* for wrapper_vmalloc_sync_mappings() */
#include <lttng/events.h>
#include <lttng/events-internal.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 lttng_kernel_ring_buffer_ctx *ctx,
				 void *client_ctx)
{
	return 0;
}

#include <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 lttng_kernel_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,
				void *priv, void *buf_addr,
				size_t subbuf_size, size_t num_subbuf,
				unsigned int switch_timer_interval,
				unsigned int read_timer_interval)
{
	struct lttng_channel *lttng_chan = priv;
	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 "LTTng: 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 lttng_kernel_ring_buffer_ctx *ctx)
{
	struct channel *chan = ctx->client_priv;
	int ret;

	memset(&ctx->priv, 0, sizeof(ctx->priv));
	ctx->priv.chan = chan;

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

}

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

static
void lttng_event_write(struct lttng_kernel_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 lttng_kernel_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 lttng_kernel_ring_buffer_ctx *ctx,
		int c, size_t len)
{
	lib_ring_buffer_memset(&client_config, ctx, c, len);
}

static
void lttng_event_strcpy(struct lttng_kernel_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 = {
		.priv = __LTTNG_COMPOUND_LITERAL(struct lttng_kernel_channel_buffer_ops_private, {
			.pub = &lttng_relay_transport.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,
			.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,
		}),
		.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,
	},
};

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_mappings();
	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 <mathieu.desnoyers@efficios.com>");
MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
		   " client");
MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
	__stringify(LTTNG_MODULES_MINOR_VERSION) "."
	__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
	LTTNG_MODULES_EXTRAVERSION);
Commit	Line	Data
	1	/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
	2	*
	3	* lttng-ring-buffer-client.h
	4	*
	5	* LTTng lib ring buffer client template.
	6	*
	7	* Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/types.h>
	12	#include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_mappings() */
	13	#include <lttng/events.h>
	14	#include <lttng/events-internal.h>
	15	#include <lttng/tracer.h>
	16
	17	static struct lttng_transport lttng_relay_transport;
	18
	19	struct metadata_packet_header {
	20	uint32_t magic; /* 0x75D11D57 */
	21	uint8_t uuid[16]; /* Unique Universal Identifier */
	22	uint32_t checksum; /* 0 if unused */
	23	uint32_t content_size; /* in bits */
	24	uint32_t packet_size; /* in bits */
	25	uint8_t compression_scheme; /* 0 if unused */
	26	uint8_t encryption_scheme; /* 0 if unused */
	27	uint8_t checksum_scheme; /* 0 if unused */
	28	uint8_t major; /* CTF spec major version number */
	29	uint8_t minor; /* CTF spec minor version number */
	30	uint8_t header_end[0];
	31	};
	32
	33	struct metadata_record_header {
	34	uint8_t header_end[0]; /* End of header */
	35	};
	36
	37	static const struct lib_ring_buffer_config client_config;
	38
	39	static inline
	40	u64 lib_ring_buffer_clock_read(struct channel *chan)
	41	{
	42	return 0;
	43	}
	44
	45	static inline
	46	size_t record_header_size(const struct lib_ring_buffer_config *config,
	47	struct channel *chan, size_t offset,
	48	size_t *pre_header_padding,
	49	struct lttng_kernel_ring_buffer_ctx *ctx,
	50	void *client_ctx)
	51	{
	52	return 0;
	53	}
	54
	55	#include <ringbuffer/api.h>
	56
	57	static u64 client_ring_buffer_clock_read(struct channel *chan)
	58	{
	59	return 0;
	60	}
	61
	62	static
	63	size_t client_record_header_size(const struct lib_ring_buffer_config *config,
	64	struct channel *chan, size_t offset,
	65	size_t *pre_header_padding,
	66	struct lttng_kernel_ring_buffer_ctx *ctx,
	67	void *client_ctx)
	68	{
	69	return 0;
	70	}
	71
	72	/**
	73	* client_packet_header_size - called on buffer-switch to a new sub-buffer
	74	*
	75	* Return header size without padding after the structure. Don't use packed
	76	* structure because gcc generates inefficient code on some architectures
	77	* (powerpc, mips..)
	78	*/
	79	static size_t client_packet_header_size(void)
	80	{
	81	return offsetof(struct metadata_packet_header, header_end);
	82	}
	83
	84	static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
	85	unsigned int subbuf_idx)
	86	{
	87	struct channel *chan = buf->backend.chan;
	88	struct metadata_packet_header *header =
	89	(struct metadata_packet_header *)
	90	lib_ring_buffer_offset_address(&buf->backend,
	91	subbuf_idx * chan->backend.subbuf_size);
	92	struct lttng_metadata_cache *metadata_cache =
	93	channel_get_private(chan);
	94
	95	header->magic = TSDL_MAGIC_NUMBER;
	96	memcpy(header->uuid, metadata_cache->uuid.b,
	97	sizeof(metadata_cache->uuid));
	98	header->checksum = 0; /* 0 if unused */
	99	header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
	100	header->packet_size = 0xFFFFFFFF; /* in bits, for debugging */
	101	header->compression_scheme = 0; /* 0 if unused */
	102	header->encryption_scheme = 0; /* 0 if unused */
	103	header->checksum_scheme = 0; /* 0 if unused */
	104	header->major = CTF_SPEC_MAJOR;
	105	header->minor = CTF_SPEC_MINOR;
	106	}
	107
	108	/*
	109	* offset is assumed to never be 0 here : never deliver a completely empty
	110	* subbuffer. data_size is between 1 and subbuf_size.
	111	*/
	112	static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
	113	unsigned int subbuf_idx, unsigned long data_size)
	114	{
	115	struct channel *chan = buf->backend.chan;
	116	struct metadata_packet_header *header =
	117	(struct metadata_packet_header *)
	118	lib_ring_buffer_offset_address(&buf->backend,
	119	subbuf_idx * chan->backend.subbuf_size);
	120	unsigned long records_lost = 0;
	121
	122	header->content_size = data_size * CHAR_BIT; /* in bits */
	123	header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
	124	/*
	125	* We do not care about the records lost count, because the metadata
	126	* channel waits and retry.
	127	*/
	128	(void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
	129	records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
	130	records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
	131	WARN_ON_ONCE(records_lost != 0);
	132	}
	133
	134	static int client_buffer_create(struct lib_ring_buffer buf, void priv,
	135	int cpu, const char *name)
	136	{
	137	return 0;
	138	}
	139
	140	static void client_buffer_finalize(struct lib_ring_buffer buf, void priv, int cpu)
	141	{
	142	}
	143
	144	static int client_timestamp_begin(const struct lib_ring_buffer_config *config,
	145	struct lib_ring_buffer buf, uint64_t timestamp_begin)
	146	{
	147	return -ENOSYS;
	148	}
	149
	150	static int client_timestamp_end(const struct lib_ring_buffer_config *config,
	151	struct lib_ring_buffer *bufb,
	152	uint64_t *timestamp_end)
	153	{
	154	return -ENOSYS;
	155	}
	156
	157	static int client_events_discarded(const struct lib_ring_buffer_config *config,
	158	struct lib_ring_buffer *bufb,
	159	uint64_t *events_discarded)
	160	{
	161	return -ENOSYS;
	162	}
	163
	164	static int client_current_timestamp(const struct lib_ring_buffer_config *config,
	165	struct lib_ring_buffer *bufb,
	166	uint64_t *ts)
	167	{
	168	return -ENOSYS;
	169	}
	170
	171	static int client_content_size(const struct lib_ring_buffer_config *config,
	172	struct lib_ring_buffer *bufb,
	173	uint64_t *content_size)
	174	{
	175	return -ENOSYS;
	176	}
	177
	178	static int client_packet_size(const struct lib_ring_buffer_config *config,
	179	struct lib_ring_buffer *bufb,
	180	uint64_t *packet_size)
	181	{
	182	return -ENOSYS;
	183	}
	184
	185	static int client_stream_id(const struct lib_ring_buffer_config *config,
	186	struct lib_ring_buffer *bufb,
	187	uint64_t *stream_id)
	188	{
	189	return -ENOSYS;
	190	}
	191
	192	static int client_sequence_number(const struct lib_ring_buffer_config *config,
	193	struct lib_ring_buffer *bufb,
	194	uint64_t *seq)
	195	{
	196	return -ENOSYS;
	197	}
	198
	199	static
	200	int client_instance_id(const struct lib_ring_buffer_config *config,
	201	struct lib_ring_buffer *bufb,
	202	uint64_t *id)
	203	{
	204	return -ENOSYS;
	205	}
	206
	207	static const struct lib_ring_buffer_config client_config = {
	208	.cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
	209	.cb.record_header_size = client_record_header_size,
	210	.cb.subbuffer_header_size = client_packet_header_size,
	211	.cb.buffer_begin = client_buffer_begin,
	212	.cb.buffer_end = client_buffer_end,
	213	.cb.buffer_create = client_buffer_create,
	214	.cb.buffer_finalize = client_buffer_finalize,
	215
	216	.tsc_bits = 0,
	217	.alloc = RING_BUFFER_ALLOC_GLOBAL,
	218	.sync = RING_BUFFER_SYNC_GLOBAL,
	219	.mode = RING_BUFFER_MODE_TEMPLATE,
	220	.backend = RING_BUFFER_PAGE,
	221	.output = RING_BUFFER_OUTPUT_TEMPLATE,
	222	.oops = RING_BUFFER_OOPS_CONSISTENCY,
	223	.ipi = RING_BUFFER_IPI_BARRIER,
	224	.wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
	225	};
	226
	227	static
	228	void release_priv_ops(void *priv_ops)
	229	{
	230	module_put(THIS_MODULE);
	231	}
	232
	233	static
	234	void lttng_channel_destroy(struct channel *chan)
	235	{
	236	channel_destroy(chan);
	237	}
	238
	239	static
	240	struct channel _channel_create(const char name,
	241	void priv, void buf_addr,
	242	size_t subbuf_size, size_t num_subbuf,
	243	unsigned int switch_timer_interval,
	244	unsigned int read_timer_interval)
	245	{
	246	struct lttng_channel *lttng_chan = priv;
	247	struct channel *chan;
	248
	249	chan = channel_create(&client_config, name,
	250	lttng_chan->session->metadata_cache, buf_addr,
	251	subbuf_size, num_subbuf, switch_timer_interval,
	252	read_timer_interval);
	253	if (chan) {
	254	/*
	255	* Ensure this module is not unloaded before we finish
	256	* using lttng_relay_transport.ops.
	257	*/
	258	if (!try_module_get(THIS_MODULE)) {
	259	printk(KERN_WARNING "LTTng: Can't lock transport module.\n");
	260	goto error;
	261	}
	262	chan->backend.priv_ops = &lttng_relay_transport.ops;
	263	chan->backend.release_priv_ops = release_priv_ops;
	264	}
	265	return chan;
	266
	267	error:
	268	lttng_channel_destroy(chan);
	269	return NULL;
	270	}
	271
	272	static
	273	struct lib_ring_buffer lttng_buffer_read_open(struct channel chan)
	274	{
	275	struct lib_ring_buffer *buf;
	276
	277	buf = channel_get_ring_buffer(&client_config, chan, 0);
	278	if (!lib_ring_buffer_open_read(buf))
	279	return buf;
	280	return NULL;
	281	}
	282
	283	static
	284	int lttng_buffer_has_read_closed_stream(struct channel *chan)
	285	{
	286	struct lib_ring_buffer *buf;
	287	int cpu;
	288
	289	for_each_channel_cpu(cpu, chan) {
	290	buf = channel_get_ring_buffer(&client_config, chan, cpu);
	291	if (!atomic_long_read(&buf->active_readers))
	292	return 1;
	293	}
	294	return 0;
	295	}
	296
	297	static
	298	void lttng_buffer_read_close(struct lib_ring_buffer *buf)
	299	{
	300	lib_ring_buffer_release_read(buf);
	301	}
	302
	303	static
	304	int lttng_event_reserve(struct lttng_kernel_ring_buffer_ctx *ctx)
	305	{
	306	struct channel *chan = ctx->client_priv;
	307	int ret;
	308
	309	memset(&ctx->priv, 0, sizeof(ctx->priv));
	310	ctx->priv.chan = chan;
	311
	312	ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
	313	if (ret)
	314	return ret;
	315	lib_ring_buffer_backend_get_pages(&client_config, ctx,
	316	&ctx->priv.backend_pages);
	317	return 0;
	318
	319	}
	320
	321	static
	322	void lttng_event_commit(struct lttng_kernel_ring_buffer_ctx *ctx)
	323	{
	324	lib_ring_buffer_commit(&client_config, ctx);
	325	}
	326
	327	static
	328	void lttng_event_write(struct lttng_kernel_ring_buffer_ctx ctx, const void src,
	329	size_t len)
	330	{
	331	lib_ring_buffer_write(&client_config, ctx, src, len);
	332	}
	333
	334	static
	335	void lttng_event_write_from_user(struct lttng_kernel_ring_buffer_ctx *ctx,
	336	const void __user *src, size_t len)
	337	{
	338	lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
	339	}
	340
	341	static
	342	void lttng_event_memset(struct lttng_kernel_ring_buffer_ctx *ctx,
	343	int c, size_t len)
	344	{
	345	lib_ring_buffer_memset(&client_config, ctx, c, len);
	346	}
	347
	348	static
	349	void lttng_event_strcpy(struct lttng_kernel_ring_buffer_ctx ctx, const char src,
	350	size_t len)
	351	{
	352	lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
	353	}
	354
	355	static
	356	size_t lttng_packet_avail_size(struct channel *chan)
	357	{
	358	unsigned long o_begin;
	359	struct lib_ring_buffer *buf;
	360
	361	buf = chan->backend.buf; /* Only for global buffer ! */
	362	o_begin = v_read(&client_config, &buf->offset);
	363	if (subbuf_offset(o_begin, chan) != 0) {
	364	return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
	365	} else {
	366	return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
	367	- sizeof(struct metadata_packet_header);
	368	}
	369	}
	370
	371	static
	372	wait_queue_head_t lttng_get_writer_buf_wait_queue(struct channel chan, int cpu)
	373	{
	374	struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
	375	chan, cpu);
	376	return &buf->write_wait;
	377	}
	378
	379	static
	380	wait_queue_head_t lttng_get_hp_wait_queue(struct channel chan)
	381	{
	382	return &chan->hp_wait;
	383	}
	384
	385	static
	386	int lttng_is_finalized(struct channel *chan)
	387	{
	388	return lib_ring_buffer_channel_is_finalized(chan);
	389	}
	390
	391	static
	392	int lttng_is_disabled(struct channel *chan)
	393	{
	394	return lib_ring_buffer_channel_is_disabled(chan);
	395	}
	396
	397	static struct lttng_transport lttng_relay_transport = {
	398	.name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
	399	.owner = THIS_MODULE,
	400	.ops = {
	401	.priv = __LTTNG_COMPOUND_LITERAL(struct lttng_kernel_channel_buffer_ops_private, {
	402	.pub = &lttng_relay_transport.ops,
	403	.channel_create = _channel_create,
	404	.channel_destroy = lttng_channel_destroy,
	405	.buffer_read_open = lttng_buffer_read_open,
	406	.buffer_has_read_closed_stream =
	407	lttng_buffer_has_read_closed_stream,
	408	.buffer_read_close = lttng_buffer_read_close,
	409	.packet_avail_size = lttng_packet_avail_size,
	410	.get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
	411	.get_hp_wait_queue = lttng_get_hp_wait_queue,
	412	.is_finalized = lttng_is_finalized,
	413	.is_disabled = lttng_is_disabled,
	414	.timestamp_begin = client_timestamp_begin,
	415	.timestamp_end = client_timestamp_end,
	416	.events_discarded = client_events_discarded,
	417	.content_size = client_content_size,
	418	.packet_size = client_packet_size,
	419	.stream_id = client_stream_id,
	420	.current_timestamp = client_current_timestamp,
	421	.sequence_number = client_sequence_number,
	422	.instance_id = client_instance_id,
	423	}),
	424	.event_reserve = lttng_event_reserve,
	425	.event_commit = lttng_event_commit,
	426	.event_write_from_user = lttng_event_write_from_user,
	427	.event_memset = lttng_event_memset,
	428	.event_write = lttng_event_write,
	429	.event_strcpy = lttng_event_strcpy,
	430	},
	431	};
	432
	433	static int __init lttng_ring_buffer_client_init(void)
	434	{
	435	/*
	436	* This vmalloc sync all also takes care of the lib ring buffer
	437	* vmalloc'd module pages when it is built as a module into LTTng.
	438	*/
	439	wrapper_vmalloc_sync_mappings();
	440	lttng_transport_register(&lttng_relay_transport);
	441	return 0;
	442	}
	443
	444	module_init(lttng_ring_buffer_client_init);
	445
	446	static void __exit lttng_ring_buffer_client_exit(void)
	447	{
	448	lttng_transport_unregister(&lttng_relay_transport);
	449	}
	450
	451	module_exit(lttng_ring_buffer_client_exit);
	452
	453	MODULE_LICENSE("GPL and additional rights");
	454	MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
	455	MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
	456	" client");
	457	MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
	458	__stringify(LTTNG_MODULES_MINOR_VERSION) "."
	459	__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
	460	LTTNG_MODULES_EXTRAVERSION);