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