lttng-ring-buffer-client.h

   1 /*
   2  * lttng-ring-buffer-client.h
   3  *
   4  * LTTng lib ring buffer client template.
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/types.h>
  25 #include "lib/bitfield.h"
  26 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  27 #include "wrapper/trace-clock.h"
  28 #include "lttng-events.h"
  29 #include "lttng-tracer.h"
  30 #include "wrapper/ringbuffer/frontend_types.h"
  31
  32 #define LTTNG_COMPACT_EVENT_BITS        5
  33 #define LTTNG_COMPACT_TSC_BITS          27
  34
  35 static struct lttng_transport lttng_relay_transport;
  36
  37 /*
  38  * Keep the natural field alignment for _each field_ within this structure if
  39  * you ever add/remove a field from this header. Packed attribute is not used
  40  * because gcc generates poor code on at least powerpc and mips. Don't ever
  41  * let gcc add padding between the structure elements.
  42  *
  43  * The guarantee we have with timestamps is that all the events in a
  44  * packet are included (inclusive) within the begin/end timestamps of
  45  * the packet. Another guarantee we have is that the "timestamp begin",
  46  * as well as the event timestamps, are monotonically increasing (never
  47  * decrease) when moving forward in a stream (physically). But this
  48  * guarantee does not apply to "timestamp end", because it is sampled at
  49  * commit time, which is not ordered with respect to space reservation.
  50  */
  51
  52 struct packet_header {
  53         /* Trace packet header */
  54         uint32_t magic;                 /*
  55                                          * Trace magic number.
  56                                          * contains endianness information.
  57                                          */
  58         uint8_t uuid[16];
  59         uint32_t stream_id;
  60
  61         struct {
  62                 /* Stream packet context */
  63                 uint64_t timestamp_begin;       /* Cycle count at subbuffer start */
  64                 uint64_t timestamp_end;         /* Cycle count at subbuffer end */
  65                 uint64_t content_size;          /* Size of data in subbuffer */
  66                 uint64_t packet_size;           /* Subbuffer size (include padding) */
  67                 uint64_t packet_seq_num;        /* Packet sequence number */
  68                 unsigned long events_discarded; /*
  69                                                  * Events lost in this subbuffer since
  70                                                  * the beginning of the trace.
  71                                                  * (may overflow)
  72                                                  */
  73                 uint32_t cpu_id;                /* CPU id associated with stream */
  74                 uint8_t header_end;             /* End of header */
  75         } ctx;
  76 };
  77
  78
  79 static inline notrace u64 lib_ring_buffer_clock_read(struct channel *chan)
  80 {
  81         return trace_clock_read64();
  82 }
  83
  84 static inline
  85 size_t ctx_get_size(size_t offset, struct lttng_ctx *ctx)
  86 {
  87         int i;
  88         size_t orig_offset = offset;
  89
  90         if (likely(!ctx))
  91                 return 0;
  92         offset += lib_ring_buffer_align(offset, ctx->largest_align);
  93         for (i = 0; i < ctx->nr_fields; i++)
  94                 offset += ctx->fields[i].get_size(offset);
  95         return offset - orig_offset;
  96 }
  97
  98 static inline
  99 void ctx_record(struct lib_ring_buffer_ctx *bufctx,
 100                 struct lttng_channel *chan,
 101                 struct lttng_ctx *ctx)
 102 {
 103         int i;
 104
 105         if (likely(!ctx))
 106                 return;
 107         lib_ring_buffer_align_ctx(bufctx, ctx->largest_align);
 108         for (i = 0; i < ctx->nr_fields; i++)
 109                 ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
 110 }
 111
 112 /*
 113  * record_header_size - Calculate the header size and padding necessary.
 114  * @config: ring buffer instance configuration
 115  * @chan: channel
 116  * @offset: offset in the write buffer
 117  * @pre_header_padding: padding to add before the header (output)
 118  * @ctx: reservation context
 119  *
 120  * Returns the event header size (including padding).
 121  *
 122  * The payload must itself determine its own alignment from the biggest type it
 123  * contains.
 124  */
 125 static __inline__
 126 unsigned char record_header_size(const struct lib_ring_buffer_config *config,
 127                                  struct channel *chan, size_t offset,
 128                                  size_t *pre_header_padding,
 129                                  struct lib_ring_buffer_ctx *ctx)
 130 {
 131         struct lttng_channel *lttng_chan = channel_get_private(chan);
 132         struct lttng_event *event = ctx->priv;
 133         size_t orig_offset = offset;
 134         size_t padding;
 135
 136         switch (lttng_chan->header_type) {
 137         case 1: /* compact */
 138                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 139                 offset += padding;
 140                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 141                         offset += sizeof(uint32_t);     /* id and timestamp */
 142                 } else {
 143                         /* Minimum space taken by LTTNG_COMPACT_EVENT_BITS id */
 144                         offset += (LTTNG_COMPACT_EVENT_BITS + CHAR_BIT - 1) / CHAR_BIT;
 145                         /* Align extended struct on largest member */
 146                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 147                         offset += sizeof(uint32_t);     /* id */
 148                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 149                         offset += sizeof(uint64_t);     /* timestamp */
 150                 }
 151                 break;
 152         case 2: /* large */
 153                 padding = lib_ring_buffer_align(offset, lttng_alignof(uint16_t));
 154                 offset += padding;
 155                 offset += sizeof(uint16_t);
 156                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 157                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint32_t));
 158                         offset += sizeof(uint32_t);     /* timestamp */
 159                 } else {
 160                         /* Align extended struct on largest member */
 161                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 162                         offset += sizeof(uint32_t);     /* id */
 163                         offset += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
 164                         offset += sizeof(uint64_t);     /* timestamp */
 165                 }
 166                 break;
 167         default:
 168                 padding = 0;
 169                 WARN_ON_ONCE(1);
 170         }
 171         offset += ctx_get_size(offset, event->ctx);
 172         offset += ctx_get_size(offset, lttng_chan->ctx);
 173
 174         *pre_header_padding = padding;
 175         return offset - orig_offset;
 176 }
 177
 178 #include "wrapper/ringbuffer/api.h"
 179
 180 static
 181 void lttng_write_event_header_slow(const struct lib_ring_buffer_config *config,
 182                                  struct lib_ring_buffer_ctx *ctx,
 183                                  uint32_t event_id);
 184
 185 /*
 186  * lttng_write_event_header
 187  *
 188  * Writes the event header to the offset (already aligned on 32-bits).
 189  *
 190  * @config: ring buffer instance configuration
 191  * @ctx: reservation context
 192  * @event_id: event ID
 193  */
 194 static __inline__
 195 void lttng_write_event_header(const struct lib_ring_buffer_config *config,
 196                             struct lib_ring_buffer_ctx *ctx,
 197                             uint32_t event_id)
 198 {
 199         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 200         struct lttng_event *event = ctx->priv;
 201
 202         if (unlikely(ctx->rflags))
 203                 goto slow_path;
 204
 205         switch (lttng_chan->header_type) {
 206         case 1: /* compact */
 207         {
 208                 uint32_t id_time = 0;
 209
 210                 bt_bitfield_write(&id_time, uint32_t,
 211                                 0,
 212                                 LTTNG_COMPACT_EVENT_BITS,
 213                                 event_id);
 214                 bt_bitfield_write(&id_time, uint32_t,
 215                                 LTTNG_COMPACT_EVENT_BITS,
 216                                 LTTNG_COMPACT_TSC_BITS,
 217                                 ctx->tsc);
 218                 lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 219                 break;
 220         }
 221         case 2: /* large */
 222         {
 223                 uint32_t timestamp = (uint32_t) ctx->tsc;
 224                 uint16_t id = event_id;
 225
 226                 lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 227                 lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 228                 lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 229                 break;
 230         }
 231         default:
 232                 WARN_ON_ONCE(1);
 233         }
 234
 235         ctx_record(ctx, lttng_chan, lttng_chan->ctx);
 236         ctx_record(ctx, lttng_chan, event->ctx);
 237         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 238
 239         return;
 240
 241 slow_path:
 242         lttng_write_event_header_slow(config, ctx, event_id);
 243 }
 244
 245 static
 246 void lttng_write_event_header_slow(const struct lib_ring_buffer_config *config,
 247                                  struct lib_ring_buffer_ctx *ctx,
 248                                  uint32_t event_id)
 249 {
 250         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 251         struct lttng_event *event = ctx->priv;
 252
 253         switch (lttng_chan->header_type) {
 254         case 1: /* compact */
 255                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 256                         uint32_t id_time = 0;
 257
 258                         bt_bitfield_write(&id_time, uint32_t,
 259                                         0,
 260                                         LTTNG_COMPACT_EVENT_BITS,
 261                                         event_id);
 262                         bt_bitfield_write(&id_time, uint32_t,
 263                                         LTTNG_COMPACT_EVENT_BITS,
 264                                         LTTNG_COMPACT_TSC_BITS, ctx->tsc);
 265                         lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
 266                 } else {
 267                         uint8_t id = 0;
 268                         uint64_t timestamp = ctx->tsc;
 269
 270                         bt_bitfield_write(&id, uint8_t,
 271                                         0,
 272                                         LTTNG_COMPACT_EVENT_BITS,
 273                                         31);
 274                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 275                         /* Align extended struct on largest member */
 276                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 277                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 278                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 279                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 280                 }
 281                 break;
 282         case 2: /* large */
 283         {
 284                 if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTTNG_RFLAG_EXTENDED))) {
 285                         uint32_t timestamp = (uint32_t) ctx->tsc;
 286                         uint16_t id = event_id;
 287
 288                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 289                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint32_t));
 290                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 291                 } else {
 292                         uint16_t id = 65535;
 293                         uint64_t timestamp = ctx->tsc;
 294
 295                         lib_ring_buffer_write(config, ctx, &id, sizeof(id));
 296                         /* Align extended struct on largest member */
 297                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 298                         lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
 299                         lib_ring_buffer_align_ctx(ctx, lttng_alignof(uint64_t));
 300                         lib_ring_buffer_write(config, ctx, &timestamp, sizeof(timestamp));
 301                 }
 302                 break;
 303         }
 304         default:
 305                 WARN_ON_ONCE(1);
 306         }
 307         ctx_record(ctx, lttng_chan, lttng_chan->ctx);
 308         ctx_record(ctx, lttng_chan, event->ctx);
 309         lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 310 }
 311
 312 static const struct lib_ring_buffer_config client_config;
 313
 314 static u64 client_ring_buffer_clock_read(struct channel *chan)
 315 {
 316         return lib_ring_buffer_clock_read(chan);
 317 }
 318
 319 static
 320 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
 321                                  struct channel *chan, size_t offset,
 322                                  size_t *pre_header_padding,
 323                                  struct lib_ring_buffer_ctx *ctx)
 324 {
 325         return record_header_size(config, chan, offset,
 326                                   pre_header_padding, ctx);
 327 }
 328
 329 /**
 330  * client_packet_header_size - called on buffer-switch to a new sub-buffer
 331  *
 332  * Return header size without padding after the structure. Don't use packed
 333  * structure because gcc generates inefficient code on some architectures
 334  * (powerpc, mips..)
 335  */
 336 static size_t client_packet_header_size(void)
 337 {
 338         return offsetof(struct packet_header, ctx.header_end);
 339 }
 340
 341 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
 342                                 unsigned int subbuf_idx)
 343 {
 344         struct channel *chan = buf->backend.chan;
 345         struct packet_header *header =
 346                 (struct packet_header *)
 347                         lib_ring_buffer_offset_address(&buf->backend,
 348                                 subbuf_idx * chan->backend.subbuf_size);
 349         struct lttng_channel *lttng_chan = channel_get_private(chan);
 350         struct lttng_session *session = lttng_chan->session;
 351
 352         header->magic = CTF_MAGIC_NUMBER;
 353         memcpy(header->uuid, session->uuid.b, sizeof(session->uuid));
 354         header->stream_id = lttng_chan->id;
 355         header->ctx.timestamp_begin = tsc;
 356         header->ctx.timestamp_end = 0;
 357         header->ctx.content_size = ~0ULL; /* for debugging */
 358         header->ctx.packet_size = ~0ULL;
 359         header->ctx.packet_seq_num = chan->backend.num_subbuf * \
 360                                      buf->backend.buf_cnt[subbuf_idx].seq_cnt + \
 361                                      subbuf_idx;
 362         header->ctx.events_discarded = 0;
 363         header->ctx.cpu_id = buf->backend.cpu;
 364 }
 365
 366 /*
 367  * offset is assumed to never be 0 here : never deliver a completely empty
 368  * subbuffer. data_size is between 1 and subbuf_size.
 369  */
 370 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 371                               unsigned int subbuf_idx, unsigned long data_size)
 372 {
 373         struct channel *chan = buf->backend.chan;
 374         struct packet_header *header =
 375                 (struct packet_header *)
 376                         lib_ring_buffer_offset_address(&buf->backend,
 377                                 subbuf_idx * chan->backend.subbuf_size);
 378         unsigned long records_lost = 0;
 379
 380         header->ctx.timestamp_end = tsc;
 381         header->ctx.content_size =
 382                 (uint64_t) data_size * CHAR_BIT;                /* in bits */
 383         header->ctx.packet_size =
 384                 (uint64_t) PAGE_ALIGN(data_size) * CHAR_BIT;    /* in bits */
 385         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 386         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 387         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 388         header->ctx.events_discarded = records_lost;
 389 }
 390
 391 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 392                                 int cpu, const char *name)
 393 {
 394         return 0;
 395 }
 396
 397 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
 398 {
 399 }
 400
 401 static struct packet_header *client_packet_header(
 402                 const struct lib_ring_buffer_config *config,
 403                 struct lib_ring_buffer *buf)
 404 {
 405         return lib_ring_buffer_read_offset_address(&buf->backend, 0);
 406 }
 407
 408 static int client_timestamp_begin(const struct lib_ring_buffer_config *config,
 409                 struct lib_ring_buffer *buf,
 410                 uint64_t *timestamp_begin)
 411 {
 412         struct packet_header *header = client_packet_header(config, buf);
 413         *timestamp_begin = header->ctx.timestamp_begin;
 414
 415         return 0;
 416 }
 417
 418 static int client_timestamp_end(const struct lib_ring_buffer_config *config,
 419                         struct lib_ring_buffer *buf,
 420                         uint64_t *timestamp_end)
 421 {
 422         struct packet_header *header = client_packet_header(config, buf);
 423         *timestamp_end = header->ctx.timestamp_end;
 424
 425         return 0;
 426 }
 427
 428 static int client_events_discarded(const struct lib_ring_buffer_config *config,
 429                         struct lib_ring_buffer *buf,
 430                         uint64_t *events_discarded)
 431 {
 432         struct packet_header *header = client_packet_header(config, buf);
 433         *events_discarded = header->ctx.events_discarded;
 434
 435         return 0;
 436 }
 437
 438 static int client_content_size(const struct lib_ring_buffer_config *config,
 439                         struct lib_ring_buffer *buf,
 440                         uint64_t *content_size)
 441 {
 442         struct packet_header *header = client_packet_header(config, buf);
 443         *content_size = header->ctx.content_size;
 444
 445         return 0;
 446 }
 447
 448 static int client_packet_size(const struct lib_ring_buffer_config *config,
 449                         struct lib_ring_buffer *buf,
 450                         uint64_t *packet_size)
 451 {
 452         struct packet_header *header = client_packet_header(config, buf);
 453         *packet_size = header->ctx.packet_size;
 454
 455         return 0;
 456 }
 457
 458 static int client_stream_id(const struct lib_ring_buffer_config *config,
 459                         struct lib_ring_buffer *buf,
 460                         uint64_t *stream_id)
 461 {
 462         struct packet_header *header = client_packet_header(config, buf);
 463         *stream_id = header->stream_id;
 464
 465         return 0;
 466 }
 467
 468 static int client_current_timestamp(const struct lib_ring_buffer_config *config,
 469                 struct lib_ring_buffer *bufb,
 470                 uint64_t *ts)
 471 {
 472         *ts = config->cb.ring_buffer_clock_read(bufb->backend.chan);
 473
 474         return 0;
 475 }
 476
 477 static int client_sequence_number(const struct lib_ring_buffer_config *config,
 478                         struct lib_ring_buffer *buf,
 479                         uint64_t *seq)
 480 {
 481         struct packet_header *header = client_packet_header(config, buf);
 482
 483         *seq = header->ctx.packet_seq_num;
 484
 485         return 0;
 486 }
 487
 488 static const struct lib_ring_buffer_config client_config = {
 489         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 490         .cb.record_header_size = client_record_header_size,
 491         .cb.subbuffer_header_size = client_packet_header_size,
 492         .cb.buffer_begin = client_buffer_begin,
 493         .cb.buffer_end = client_buffer_end,
 494         .cb.buffer_create = client_buffer_create,
 495         .cb.buffer_finalize = client_buffer_finalize,
 496
 497         .tsc_bits = LTTNG_COMPACT_TSC_BITS,
 498         .alloc = RING_BUFFER_ALLOC_PER_CPU,
 499         .sync = RING_BUFFER_SYNC_PER_CPU,
 500         .mode = RING_BUFFER_MODE_TEMPLATE,
 501         .backend = RING_BUFFER_PAGE,
 502         .output = RING_BUFFER_OUTPUT_TEMPLATE,
 503         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 504         .ipi = RING_BUFFER_IPI_BARRIER,
 505         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 506 };
 507
 508 static
 509 void release_priv_ops(void *priv_ops)
 510 {
 511         module_put(THIS_MODULE);
 512 }
 513
 514 static
 515 void lttng_channel_destroy(struct channel *chan)
 516 {
 517         channel_destroy(chan);
 518 }
 519
 520 static
 521 struct channel *_channel_create(const char *name,
 522                                 struct lttng_channel *lttng_chan, void *buf_addr,
 523                                 size_t subbuf_size, size_t num_subbuf,
 524                                 unsigned int switch_timer_interval,
 525                                 unsigned int read_timer_interval)
 526 {
 527         struct channel *chan;
 528
 529         chan = channel_create(&client_config, name, lttng_chan, buf_addr,
 530                               subbuf_size, num_subbuf, switch_timer_interval,
 531                               read_timer_interval);
 532         if (chan) {
 533                 /*
 534                  * Ensure this module is not unloaded before we finish
 535                  * using lttng_relay_transport.ops.
 536                  */
 537                 if (!try_module_get(THIS_MODULE)) {
 538                         printk(KERN_WARNING "LTT : Can't lock transport module.\n");
 539                         goto error;
 540                 }
 541                 chan->backend.priv_ops = &lttng_relay_transport.ops;
 542                 chan->backend.release_priv_ops = release_priv_ops;
 543         }
 544         return chan;
 545
 546 error:
 547         lttng_channel_destroy(chan);
 548         return NULL;
 549 }
 550
 551 static
 552 struct lib_ring_buffer *lttng_buffer_read_open(struct channel *chan)
 553 {
 554         struct lib_ring_buffer *buf;
 555         int cpu;
 556
 557         for_each_channel_cpu(cpu, chan) {
 558                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 559                 if (!lib_ring_buffer_open_read(buf))
 560                         return buf;
 561         }
 562         return NULL;
 563 }
 564
 565 static
 566 int lttng_buffer_has_read_closed_stream(struct channel *chan)
 567 {
 568         struct lib_ring_buffer *buf;
 569         int cpu;
 570
 571         for_each_channel_cpu(cpu, chan) {
 572                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 573                 if (!atomic_long_read(&buf->active_readers))
 574                         return 1;
 575         }
 576         return 0;
 577 }
 578
 579 static
 580 void lttng_buffer_read_close(struct lib_ring_buffer *buf)
 581 {
 582         lib_ring_buffer_release_read(buf);
 583 }
 584
 585 static
 586 int lttng_event_reserve(struct lib_ring_buffer_ctx *ctx,
 587                       uint32_t event_id)
 588 {
 589         struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
 590         int ret, cpu;
 591
 592         cpu = lib_ring_buffer_get_cpu(&client_config);
 593         if (cpu < 0)
 594                 return -EPERM;
 595         ctx->cpu = cpu;
 596
 597         switch (lttng_chan->header_type) {
 598         case 1: /* compact */
 599                 if (event_id > 30)
 600                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 601                 break;
 602         case 2: /* large */
 603                 if (event_id > 65534)
 604                         ctx->rflags |= LTTNG_RFLAG_EXTENDED;
 605                 break;
 606         default:
 607                 WARN_ON_ONCE(1);
 608         }
 609
 610         ret = lib_ring_buffer_reserve(&client_config, ctx);
 611         if (ret)
 612                 goto put;
 613         lttng_write_event_header(&client_config, ctx, event_id);
 614         return 0;
 615 put:
 616         lib_ring_buffer_put_cpu(&client_config);
 617         return ret;
 618 }
 619
 620 static
 621 void lttng_event_commit(struct lib_ring_buffer_ctx *ctx)
 622 {
 623         lib_ring_buffer_commit(&client_config, ctx);
 624         lib_ring_buffer_put_cpu(&client_config);
 625 }
 626
 627 static
 628 void lttng_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 629                      size_t len)
 630 {
 631         lib_ring_buffer_write(&client_config, ctx, src, len);
 632 }
 633
 634 static
 635 void lttng_event_write_from_user(struct lib_ring_buffer_ctx *ctx,
 636                                const void __user *src, size_t len)
 637 {
 638         lib_ring_buffer_copy_from_user_inatomic(&client_config, ctx, src, len);
 639 }
 640
 641 static
 642 void lttng_event_memset(struct lib_ring_buffer_ctx *ctx,
 643                 int c, size_t len)
 644 {
 645         lib_ring_buffer_memset(&client_config, ctx, c, len);
 646 }
 647
 648 static
 649 void lttng_event_strcpy(struct lib_ring_buffer_ctx *ctx, const char *src,
 650                 size_t len)
 651 {
 652         lib_ring_buffer_strcpy(&client_config, ctx, src, len, '#');
 653 }
 654
 655 static
 656 void lttng_event_strcpy_from_user(struct lib_ring_buffer_ctx *ctx,
 657                 const char __user *src, size_t len)
 658 {
 659         lib_ring_buffer_strcpy_from_user_inatomic(&client_config, ctx, src,
 660                         len, '#');
 661 }
 662
 663 static
 664 wait_queue_head_t *lttng_get_writer_buf_wait_queue(struct channel *chan, int cpu)
 665 {
 666         struct lib_ring_buffer *buf = channel_get_ring_buffer(&client_config,
 667                                         chan, cpu);
 668         return &buf->write_wait;
 669 }
 670
 671 static
 672 wait_queue_head_t *lttng_get_hp_wait_queue(struct channel *chan)
 673 {
 674         return &chan->hp_wait;
 675 }
 676
 677 static
 678 int lttng_is_finalized(struct channel *chan)
 679 {
 680         return lib_ring_buffer_channel_is_finalized(chan);
 681 }
 682
 683 static
 684 int lttng_is_disabled(struct channel *chan)
 685 {
 686         return lib_ring_buffer_channel_is_disabled(chan);
 687 }
 688
 689 static struct lttng_transport lttng_relay_transport = {
 690         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 691         .owner = THIS_MODULE,
 692         .ops = {
 693                 .channel_create = _channel_create,
 694                 .channel_destroy = lttng_channel_destroy,
 695                 .buffer_read_open = lttng_buffer_read_open,
 696                 .buffer_has_read_closed_stream =
 697                         lttng_buffer_has_read_closed_stream,
 698                 .buffer_read_close = lttng_buffer_read_close,
 699                 .event_reserve = lttng_event_reserve,
 700                 .event_commit = lttng_event_commit,
 701                 .event_write = lttng_event_write,
 702                 .event_write_from_user = lttng_event_write_from_user,
 703                 .event_memset = lttng_event_memset,
 704                 .event_strcpy = lttng_event_strcpy,
 705                 .event_strcpy_from_user = lttng_event_strcpy_from_user,
 706                 .packet_avail_size = NULL,      /* Would be racy anyway */
 707                 .get_writer_buf_wait_queue = lttng_get_writer_buf_wait_queue,
 708                 .get_hp_wait_queue = lttng_get_hp_wait_queue,
 709                 .is_finalized = lttng_is_finalized,
 710                 .is_disabled = lttng_is_disabled,
 711                 .timestamp_begin = client_timestamp_begin,
 712                 .timestamp_end = client_timestamp_end,
 713                 .events_discarded = client_events_discarded,
 714                 .content_size = client_content_size,
 715                 .packet_size = client_packet_size,
 716                 .stream_id = client_stream_id,
 717                 .current_timestamp = client_current_timestamp,
 718                 .sequence_number = client_sequence_number,
 719         },
 720 };
 721
 722 static int __init lttng_ring_buffer_client_init(void)
 723 {
 724         /*
 725          * This vmalloc sync all also takes care of the lib ring buffer
 726          * vmalloc'd module pages when it is built as a module into LTTng.
 727          */
 728         wrapper_vmalloc_sync_all();
 729         lttng_transport_register(&lttng_relay_transport);
 730         return 0;
 731 }
 732
 733 module_init(lttng_ring_buffer_client_init);
 734
 735 static void __exit lttng_ring_buffer_client_exit(void)
 736 {
 737         lttng_transport_unregister(&lttng_relay_transport);
 738 }
 739
 740 module_exit(lttng_ring_buffer_client_exit);
 741
 742 MODULE_LICENSE("GPL and additional rights");
 743 MODULE_AUTHOR("Mathieu Desnoyers");
 744 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 745                    " client");