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