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