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

/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
 *
 * lttng-ring-buffer-trigger-client.h
 *
 * LTTng lib ring buffer trigger client template.
 *
 * Copyright (C) 2010-2020 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#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 trigger_packet_header {
	uint32_t magic;			/* 0x75D11D57 */
	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 trigger_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 trigger_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 trigger_packet_header *header =
		(struct trigger_packet_header *)
			lib_ring_buffer_offset_address(&buf->backend,
				subbuf_idx * chan->backend.subbuf_size);

	header->magic = TSDL_MAGIC_NUMBER;
	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 trigger_packet_header *header =
		(struct trigger_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 trigger
	 * 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 void client_record_get(const struct lib_ring_buffer_config *config,
	struct channel *chan, struct lib_ring_buffer *buf,
	size_t offset, size_t *header_len,
	size_t *payload_len, u64 *timestamp)
{
	struct trigger_record_header header;
	int ret;

	ret = lib_ring_buffer_read(&buf->backend, offset, &header,
			offsetof(struct trigger_record_header, header_end));
	CHAN_WARN_ON(chan, ret != offsetof(struct trigger_record_header, header_end));
	*header_len = offsetof(struct trigger_record_header, header_end);
	/*
	 * Currently, only 64-bit trigger ID.
	 */
	*payload_len = sizeof(uint64_t);
	*timestamp = 0;
}

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,
	.cb.record_get = client_record_get,

	.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_NO_IPI_BARRIER,
	.wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
};

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_trigger_group *trigger_group = priv;
	struct channel *chan;

	chan = channel_create(&client_config, name,
			      trigger_group, 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 trigger_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_trigger_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_trigger_client_init);

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

module_exit(lttng_ring_buffer_trigger_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
63629d86 FD	1	/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
	2	*
	3	* lttng-ring-buffer-trigger-client.h
	4	*
	5	* LTTng lib ring buffer trigger client template.
	6	*
	7	* Copyright (C) 2010-2020 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_all() */
	13	#include <lttng-events.h>
	14	#include <lttng-tracer.h>
	15
	16	static struct lttng_transport lttng_relay_transport;
	17
	18	struct trigger_packet_header {
	19	uint32_t magic; /* 0x75D11D57 */
	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 trigger_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 trigger_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 trigger_packet_header *header =
87	(struct trigger_packet_header *)
88	lib_ring_buffer_offset_address(&buf->backend,
89	subbuf_idx * chan->backend.subbuf_size);
90
91	header->magic = TSDL_MAGIC_NUMBER;
92	header->checksum = 0; /* 0 if unused */
93	header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
94	header->packet_size = 0xFFFFFFFF; /* in bits, for debugging */
95	header->compression_scheme = 0; /* 0 if unused */
96	header->encryption_scheme = 0; /* 0 if unused */
97	header->checksum_scheme = 0; /* 0 if unused */
98	header->major = CTF_SPEC_MAJOR;
99	header->minor = CTF_SPEC_MINOR;
100	}
101
102	/*
103	* offset is assumed to never be 0 here : never deliver a completely empty
104	* subbuffer. data_size is between 1 and subbuf_size.
105	*/
106	static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
107	unsigned int subbuf_idx, unsigned long data_size)
108	{
109	struct channel *chan = buf->backend.chan;
110	struct trigger_packet_header *header =
111	(struct trigger_packet_header *)
112	lib_ring_buffer_offset_address(&buf->backend,
113	subbuf_idx * chan->backend.subbuf_size);
114	unsigned long records_lost = 0;
115
116	header->content_size = data_size * CHAR_BIT; /* in bits */
117	header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
118	/*
119	* We do not care about the records lost count, because the trigger
120	* channel waits and retry.
121	*/
122	(void) lib_ring_buffer_get_records_lost_full(&client_config, buf);
123	records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
124	records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
125	WARN_ON_ONCE(records_lost != 0);
126	}
127
128	static int client_buffer_create(struct lib_ring_buffer buf, void priv,
129	int cpu, const char *name)
130	{
131	return 0;
132	}
133
134	static void client_buffer_finalize(struct lib_ring_buffer buf, void priv, int cpu)
135	{
136	}
137
138	static int client_timestamp_begin(const struct lib_ring_buffer_config *config,
139	struct lib_ring_buffer buf, uint64_t timestamp_begin)
140	{
141	return -ENOSYS;
142	}
143
144	static int client_timestamp_end(const struct lib_ring_buffer_config *config,
145	struct lib_ring_buffer *bufb,
146	uint64_t *timestamp_end)
147	{
148	return -ENOSYS;
149	}
150
151	static int client_events_discarded(const struct lib_ring_buffer_config *config,
152	struct lib_ring_buffer *bufb,
153	uint64_t *events_discarded)
154	{
155	return -ENOSYS;
156	}
157
158	static int client_current_timestamp(const struct lib_ring_buffer_config *config,
159	struct lib_ring_buffer *bufb,
160	uint64_t *ts)
161	{
162	return -ENOSYS;
163	}
164
165	static int client_content_size(const struct lib_ring_buffer_config *config,
166	struct lib_ring_buffer *bufb,
167	uint64_t *content_size)
168	{
169	return -ENOSYS;
170	}
171
172	static int client_packet_size(const struct lib_ring_buffer_config *config,
173	struct lib_ring_buffer *bufb,
174	uint64_t *packet_size)
175	{
176	return -ENOSYS;
177	}
178
179	static int client_stream_id(const struct lib_ring_buffer_config *config,
180	struct lib_ring_buffer *bufb,
181	uint64_t *stream_id)
182	{
183	return -ENOSYS;
184	}
185
186	static int client_sequence_number(const struct lib_ring_buffer_config *config,
187	struct lib_ring_buffer *bufb,
188	uint64_t *seq)
189	{
190	return -ENOSYS;
191	}
192
193	static
194	int client_instance_id(const struct lib_ring_buffer_config *config,
195	struct lib_ring_buffer *bufb,
196	uint64_t *id)
197	{
198	return -ENOSYS;
199	}
200
201	static void client_record_get(const struct lib_ring_buffer_config *config,
202	struct channel chan, struct lib_ring_buffer buf,
203	size_t offset, size_t *header_len,
204	size_t payload_len, u64 timestamp)
205	{
206	struct trigger_record_header header;
207	int ret;
208
209	ret = lib_ring_buffer_read(&buf->backend, offset, &header,
210	offsetof(struct trigger_record_header, header_end));
211	CHAN_WARN_ON(chan, ret != offsetof(struct trigger_record_header, header_end));
212	*header_len = offsetof(struct trigger_record_header, header_end);
213	/*
214	* Currently, only 64-bit trigger ID.
215	*/
216	*payload_len = sizeof(uint64_t);
217	*timestamp = 0;
218	}
219
220	static const struct lib_ring_buffer_config client_config = {
221	.cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
222	.cb.record_header_size = client_record_header_size,
223	.cb.subbuffer_header_size = client_packet_header_size,
224	.cb.buffer_begin = client_buffer_begin,
225	.cb.buffer_end = client_buffer_end,
226	.cb.buffer_create = client_buffer_create,
227	.cb.buffer_finalize = client_buffer_finalize,
228	.cb.record_get = client_record_get,
229
230	.tsc_bits = 0,
231	.alloc = RING_BUFFER_ALLOC_GLOBAL,
232	.sync = RING_BUFFER_SYNC_GLOBAL,
233	.mode = RING_BUFFER_MODE_TEMPLATE,
234	.backend = RING_BUFFER_PAGE,
235	.output = RING_BUFFER_OUTPUT_TEMPLATE,
236	.oops = RING_BUFFER_OOPS_CONSISTENCY,
237	.ipi = RING_BUFFER_NO_IPI_BARRIER,
238	.wakeup = RING_BUFFER_WAKEUP_BY_WRITER,
239	};
240
241	static
242	void release_priv_ops(void *priv_ops)
243	{
244	module_put(THIS_MODULE);
245	}
246
247	static
248	void lttng_channel_destroy(struct channel *chan)
249	{
250	channel_destroy(chan);
251	}
252
253	static
254	struct channel _channel_create(const char name,
255	void priv, void buf_addr,
256	size_t subbuf_size, size_t num_subbuf,
257	unsigned int switch_timer_interval,
258	unsigned int read_timer_interval)
259	{
260	struct lttng_trigger_group *trigger_group = priv;
261	struct channel *chan;
262
263	chan = channel_create(&client_config, name,
264	trigger_group, buf_addr,
265	subbuf_size, num_subbuf, switch_timer_interval,
266	read_timer_interval);
267	if (chan) {
268	/*
269	* Ensure this module is not unloaded before we finish
270	* using lttng_relay_transport.ops.
271	*/
272	if (!try_module_get(THIS_MODULE)) {
273	printk(KERN_WARNING "LTT : Can't lock transport module.\n");
274	goto error;
275	}
276	chan->backend.priv_ops = &lttng_relay_transport.ops;
277	chan->backend.release_priv_ops = release_priv_ops;
278	}
279	return chan;
280
281	error:
282	lttng_channel_destroy(chan);
283	return NULL;
284	}
285
286	static
287	struct lib_ring_buffer lttng_buffer_read_open(struct channel chan)
288	{
289	struct lib_ring_buffer *buf;
290
291	buf = channel_get_ring_buffer(&client_config, chan, 0);
292	if (!lib_ring_buffer_open_read(buf))
293	return buf;
294	return NULL;
295	}
296
297	static
298	int lttng_buffer_has_read_closed_stream(struct channel *chan)
299	{
300	struct lib_ring_buffer *buf;
301	int cpu;
302
303	for_each_channel_cpu(cpu, chan) {
304	buf = channel_get_ring_buffer(&client_config, chan, cpu);
305	if (!atomic_long_read(&buf->active_readers))
306	return 1;
307	}
308	return 0;
309	}
310
311	static
312	void lttng_buffer_read_close(struct lib_ring_buffer *buf)
313	{
314	lib_ring_buffer_release_read(buf);
315	}
316
317	static
318	int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
319	{
320	int ret;
321
322	ret = lib_ring_buffer_reserve(&client_config, ctx, NULL);
323	if (ret)
324	return ret;
325	lib_ring_buffer_backend_get_pages(&client_config, ctx,
326	&ctx->backend_pages);
327	return 0;
328	}
329
330	static
331	void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
332	{
333	lib_ring_buffer_commit(&client_config, ctx);
334	}
335
336	static
337	void lttng_event_write(struct lib_ring_buffer_ctx ctx, const void src,
338	size_t len)
339	{
340	lib_ring_buffer_write(&client_config, ctx, src, len);
341	}
342
343	static
344	void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
345	const void __user *src, size_t len)
346	{
347	lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
348	}
349
350	static
351	void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
352	int c, size_t len)
353	{
354	lib_ring_buffer_memset(&client_config, ctx, c, len);
355	}
356
357	static
358	void lttng_event_strcpy(struct lib_ring_buffer_ctx ctx, const char src,
359	size_t len)
360	{
361	lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
362	}
363
364	static
365	size_t lttng_packet_avail_size(struct channel *chan)
366	{
367	unsigned long o_begin;
368	struct lib_ring_buffer *buf;
369
370	buf = chan->backend.buf; /* Only for global buffer ! */
371	o_begin = v_read(&client_config, &buf->offset);
372	if (subbuf_offset(o_begin, chan) != 0) {
373	return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
374	} else {
375	return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
376	- sizeof(struct trigger_packet_header);
377	}
378	}
379
380	static
381	wait_queue_head_t lttng_get_writer_buf_wait_queue(struct channel chan, int cpu)
382	{
383	struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
384	chan, cpu);
385	return &buf->write_wait;
386	}
387
388	static
389	wait_queue_head_t lttng_get_hp_wait_queue(struct channel chan)
390	{
391	return &chan->hp_wait;
392	}
393
394	static
395	int lttng_is_finalized(struct channel *chan)
396	{
397	return lib_ring_buffer_channel_is_finalized(chan);
398	}
399
400	static
401	int lttng_is_disabled(struct channel *chan)
402	{
403	return lib_ring_buffer_channel_is_disabled(chan);
404	}
405
406	static struct lttng_transport lttng_relay_transport = {
407	.name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
408	.owner = THIS_MODULE,
409	.ops = {
410	.channel_create = _channel_create,
411	.channel_destroy = lttng_channel_destroy,
412	.buffer_read_open = lttng_buffer_read_open,
413	.buffer_has_read_closed_stream =
414	lttng_buffer_has_read_closed_stream,
415	.buffer_read_close = lttng_buffer_read_close,
416	.event_reserve = lttng_event_reserve,
417	.event_commit = lttng_event_commit,
418	.event_write_from_user = lttng_event_write_from_user,
419	.event_memset = lttng_event_memset,
420	.event_write = lttng_event_write,
421	.event_strcpy = lttng_event_strcpy,
422	.packet_avail_size = lttng_packet_avail_size,
423	.get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
424	.get_hp_wait_queue = lttng_get_hp_wait_queue,
425	.is_finalized = lttng_is_finalized,
426	.is_disabled = lttng_is_disabled,
427	.timestamp_begin = client_timestamp_begin,
428	.timestamp_end = client_timestamp_end,
429	.events_discarded = client_events_discarded,
430	.content_size = client_content_size,
431	.packet_size = client_packet_size,
432	.stream_id = client_stream_id,
433	.current_timestamp = client_current_timestamp,
434	.sequence_number = client_sequence_number,
435	.instance_id = client_instance_id,
436	},
437	};
438
439	static int __init lttng_ring_buffer_trigger_client_init(void)
440	{
441	/*
442	* This vmalloc sync all also takes care of the lib ring buffer
443	* vmalloc'd module pages when it is built as a module into LTTng.
444	*/
445	wrapper_vmalloc_sync_all();
446	lttng_transport_register(&lttng_relay_transport);
447	return 0;
448	}
449
450	module_init(lttng_ring_buffer_trigger_client_init);
451
452	static void __exit lttng_ring_buffer_trigger_client_exit(void)
453	{
454	lttng_transport_unregister(&lttng_relay_transport);
455	}
456
457	module_exit(lttng_ring_buffer_trigger_client_exit);
458
459	MODULE_LICENSE("GPL and additional rights");
460	MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
461	MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
462	" client");
463	MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
464	__stringify(LTTNG_MODULES_MINOR_VERSION) "."
465	__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
466	LTTNG_MODULES_EXTRAVERSION);