| 1 | /* |
| 2 | * tracer.c |
| 3 | * |
| 4 | * (C) Copyright 2005-2008 - |
| 5 | * Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca) |
| 6 | * |
| 7 | * This library is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU Lesser General Public |
| 9 | * License as published by the Free Software Foundation; either |
| 10 | * version 2.1 of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * This library is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * Lesser General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Lesser General Public |
| 18 | * License along with this library; if not, write to the Free Software |
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 20 | * |
| 21 | * Inspired from LTT : |
| 22 | * Karim Yaghmour (karim@opersys.com) |
| 23 | * Tom Zanussi (zanussi@us.ibm.com) |
| 24 | * Bob Wisniewski (bob@watson.ibm.com) |
| 25 | * And from K42 : |
| 26 | * Bob Wisniewski (bob@watson.ibm.com) |
| 27 | * |
| 28 | * Changelog: |
| 29 | * 22/09/06, Move to the marker/probes mechanism. |
| 30 | * 19/10/05, Complete lockless mechanism. |
| 31 | * 27/05/05, Modular redesign and rewrite. |
| 32 | */ |
| 33 | |
| 34 | #include <urcu-bp.h> |
| 35 | #include <urcu/rculist.h> |
| 36 | |
| 37 | #include <ust/clock.h> |
| 38 | |
| 39 | #include "tracercore.h" |
| 40 | #include "tracer.h" |
| 41 | #include "usterr.h" |
| 42 | |
| 43 | struct chan_info_struct chan_infos[] = { |
| 44 | [LTT_CHANNEL_METADATA] = { |
| 45 | LTT_METADATA_CHANNEL, |
| 46 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 47 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 48 | }, |
| 49 | [LTT_CHANNEL_UST] = { |
| 50 | LTT_UST_CHANNEL, |
| 51 | LTT_DEFAULT_SUBBUF_SIZE_HIGH, |
| 52 | LTT_DEFAULT_N_SUBBUFS_HIGH, |
| 53 | }, |
| 54 | }; |
| 55 | |
| 56 | static enum ltt_channels get_channel_type_from_name(const char *name) |
| 57 | { |
| 58 | int i; |
| 59 | |
| 60 | if (!name) |
| 61 | return LTT_CHANNEL_UST; |
| 62 | |
| 63 | for (i = 0; i < ARRAY_SIZE(chan_infos); i++) |
| 64 | if (chan_infos[i].name && !strcmp(name, chan_infos[i].name)) |
| 65 | return (enum ltt_channels)i; |
| 66 | |
| 67 | return LTT_CHANNEL_UST; |
| 68 | } |
| 69 | |
| 70 | static CDS_LIST_HEAD(ltt_transport_list); |
| 71 | /* transport mutex, nests inside traces mutex (ltt_lock_traces) */ |
| 72 | static DEFINE_MUTEX(ltt_transport_mutex); |
| 73 | /** |
| 74 | * ltt_transport_register - LTT transport registration |
| 75 | * @transport: transport structure |
| 76 | * |
| 77 | * Registers a transport which can be used as output to extract the data out of |
| 78 | * LTTng. The module calling this registration function must ensure that no |
| 79 | * trap-inducing code will be executed by the transport functions. E.g. |
| 80 | * vmalloc_sync_all() must be called between a vmalloc and the moment the memory |
| 81 | * is made visible to the transport function. This registration acts as a |
| 82 | * vmalloc_sync_all. Therefore, only if the module allocates virtual memory |
| 83 | * after its registration must it synchronize the TLBs. |
| 84 | */ |
| 85 | void ltt_transport_register(struct ltt_transport *transport) |
| 86 | { |
| 87 | pthread_mutex_lock(<t_transport_mutex); |
| 88 | cds_list_add_tail(&transport->node, <t_transport_list); |
| 89 | pthread_mutex_unlock(<t_transport_mutex); |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * ltt_transport_unregister - LTT transport unregistration |
| 94 | * @transport: transport structure |
| 95 | */ |
| 96 | void ltt_transport_unregister(struct ltt_transport *transport) |
| 97 | { |
| 98 | pthread_mutex_lock(<t_transport_mutex); |
| 99 | cds_list_del(&transport->node); |
| 100 | pthread_mutex_unlock(<t_transport_mutex); |
| 101 | } |
| 102 | |
| 103 | static inline int is_channel_overwrite(enum ltt_channels chan, |
| 104 | enum trace_mode mode) |
| 105 | { |
| 106 | switch (mode) { |
| 107 | case LTT_TRACE_NORMAL: |
| 108 | return 0; |
| 109 | case LTT_TRACE_FLIGHT: |
| 110 | switch (chan) { |
| 111 | case LTT_CHANNEL_METADATA: |
| 112 | return 0; |
| 113 | default: |
| 114 | return 1; |
| 115 | } |
| 116 | case LTT_TRACE_HYBRID: |
| 117 | switch (chan) { |
| 118 | case LTT_CHANNEL_METADATA: |
| 119 | return 0; |
| 120 | default: |
| 121 | return 1; |
| 122 | } |
| 123 | default: |
| 124 | return 0; |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | static void trace_async_wakeup(struct ust_trace *trace) |
| 129 | { |
| 130 | int i; |
| 131 | struct ust_channel *chan; |
| 132 | |
| 133 | /* Must check each channel for pending read wakeup */ |
| 134 | for (i = 0; i < trace->nr_channels; i++) { |
| 135 | chan = &trace->channels[i]; |
| 136 | if (chan->active) |
| 137 | trace->ops->wakeup_channel(chan); |
| 138 | } |
| 139 | } |
| 140 | |
| 141 | /** |
| 142 | * _ltt_trace_find - find a trace by given name. |
| 143 | * trace_name: trace name |
| 144 | * |
| 145 | * Returns a pointer to the trace structure, NULL if not found. |
| 146 | */ |
| 147 | struct ust_trace *_ltt_trace_find(const char *trace_name) |
| 148 | { |
| 149 | struct ust_trace *trace; |
| 150 | |
| 151 | cds_list_for_each_entry(trace, <t_traces.head, list) |
| 152 | if (!strncmp(trace->trace_name, trace_name, NAME_MAX)) |
| 153 | return trace; |
| 154 | |
| 155 | return NULL; |
| 156 | } |
| 157 | |
| 158 | /* _ltt_trace_find_setup : |
| 159 | * find a trace in setup list by given name. |
| 160 | * |
| 161 | * Returns a pointer to the trace structure, NULL if not found. |
| 162 | */ |
| 163 | struct ust_trace *_ltt_trace_find_setup(const char *trace_name) |
| 164 | { |
| 165 | struct ust_trace *trace; |
| 166 | |
| 167 | cds_list_for_each_entry(trace, <t_traces.setup_head, list) |
| 168 | if (!strncmp(trace->trace_name, trace_name, NAME_MAX)) |
| 169 | return trace; |
| 170 | |
| 171 | return NULL; |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * ltt_release_transport - Release an LTT transport |
| 176 | * @kref : reference count on the transport |
| 177 | */ |
| 178 | void ltt_release_transport(struct urcu_ref *urcu_ref) |
| 179 | { |
| 180 | return; |
| 181 | } |
| 182 | |
| 183 | /** |
| 184 | * ltt_release_trace - Release a LTT trace |
| 185 | * @kref : reference count on the trace |
| 186 | */ |
| 187 | void ltt_release_trace(struct urcu_ref *urcu_ref) |
| 188 | { |
| 189 | struct ust_trace *trace = _ust_container_of(urcu_ref, |
| 190 | struct ust_trace, urcu_ref); |
| 191 | ltt_channels_trace_free(trace->channels); |
| 192 | free(trace); |
| 193 | } |
| 194 | |
| 195 | static inline void prepare_chan_size_num(unsigned int *subbuf_size, |
| 196 | unsigned int *n_subbufs) |
| 197 | { |
| 198 | /* Make sure the subbuffer size is larger than a page */ |
| 199 | *subbuf_size = max_t(unsigned int, *subbuf_size, PAGE_SIZE); |
| 200 | |
| 201 | /* round to next power of 2 */ |
| 202 | *subbuf_size = 1 << get_count_order(*subbuf_size); |
| 203 | *n_subbufs = 1 << get_count_order(*n_subbufs); |
| 204 | |
| 205 | /* Subbuf size and number must both be power of two */ |
| 206 | WARN_ON(hweight32(*subbuf_size) != 1); |
| 207 | WARN_ON(hweight32(*n_subbufs) != 1); |
| 208 | } |
| 209 | |
| 210 | int _ltt_trace_setup(const char *trace_name) |
| 211 | { |
| 212 | int err = 0; |
| 213 | struct ust_trace *new_trace = NULL; |
| 214 | int metadata_index; |
| 215 | unsigned int chan; |
| 216 | enum ltt_channels chantype; |
| 217 | |
| 218 | if (_ltt_trace_find_setup(trace_name)) { |
| 219 | ERR("Trace name %s already used", trace_name); |
| 220 | err = -EEXIST; |
| 221 | goto traces_error; |
| 222 | } |
| 223 | |
| 224 | if (_ltt_trace_find(trace_name)) { |
| 225 | ERR("Trace name %s already used", trace_name); |
| 226 | err = -EEXIST; |
| 227 | goto traces_error; |
| 228 | } |
| 229 | |
| 230 | new_trace = zmalloc(sizeof(struct ust_trace)); |
| 231 | if (!new_trace) { |
| 232 | ERR("Unable to allocate memory for trace %s", trace_name); |
| 233 | err = -ENOMEM; |
| 234 | goto traces_error; |
| 235 | } |
| 236 | strncpy(new_trace->trace_name, trace_name, NAME_MAX); |
| 237 | new_trace->channels = ltt_channels_trace_alloc(&new_trace->nr_channels, |
| 238 | ust_channels_overwrite_by_default, |
| 239 | ust_channels_request_collection_by_default, 1); |
| 240 | if (!new_trace->channels) { |
| 241 | ERR("Unable to allocate memory for chaninfo %s\n", trace_name); |
| 242 | err = -ENOMEM; |
| 243 | goto trace_free; |
| 244 | } |
| 245 | |
| 246 | /* |
| 247 | * Force metadata channel to active, no overwrite. |
| 248 | */ |
| 249 | metadata_index = ltt_channels_get_index_from_name("metadata"); |
| 250 | WARN_ON(metadata_index < 0); |
| 251 | new_trace->channels[metadata_index].overwrite = 0; |
| 252 | new_trace->channels[metadata_index].active = 1; |
| 253 | |
| 254 | /* |
| 255 | * Set hardcoded tracer defaults for some channels |
| 256 | */ |
| 257 | for (chan = 0; chan < new_trace->nr_channels; chan++) { |
| 258 | if (!(new_trace->channels[chan].active)) |
| 259 | continue; |
| 260 | |
| 261 | chantype = get_channel_type_from_name( |
| 262 | ltt_channels_get_name_from_index(chan)); |
| 263 | new_trace->channels[chan].subbuf_size = |
| 264 | chan_infos[chantype].def_subbufsize; |
| 265 | new_trace->channels[chan].subbuf_cnt = |
| 266 | chan_infos[chantype].def_subbufcount; |
| 267 | } |
| 268 | |
| 269 | cds_list_add(&new_trace->list, <t_traces.setup_head); |
| 270 | return 0; |
| 271 | |
| 272 | trace_free: |
| 273 | free(new_trace); |
| 274 | traces_error: |
| 275 | return err; |
| 276 | } |
| 277 | |
| 278 | |
| 279 | int ltt_trace_setup(const char *trace_name) |
| 280 | { |
| 281 | int ret; |
| 282 | ltt_lock_traces(); |
| 283 | ret = _ltt_trace_setup(trace_name); |
| 284 | ltt_unlock_traces(); |
| 285 | return ret; |
| 286 | } |
| 287 | |
| 288 | /* must be called from within a traces lock. */ |
| 289 | static void _ltt_trace_free(struct ust_trace *trace) |
| 290 | { |
| 291 | cds_list_del(&trace->list); |
| 292 | free(trace); |
| 293 | } |
| 294 | |
| 295 | int ltt_trace_set_type(const char *trace_name, const char *trace_type) |
| 296 | { |
| 297 | int err = 0; |
| 298 | struct ust_trace *trace; |
| 299 | struct ltt_transport *tran_iter, *transport = NULL; |
| 300 | |
| 301 | ltt_lock_traces(); |
| 302 | |
| 303 | trace = _ltt_trace_find_setup(trace_name); |
| 304 | if (!trace) { |
| 305 | ERR("Trace not found %s", trace_name); |
| 306 | err = -ENOENT; |
| 307 | goto traces_error; |
| 308 | } |
| 309 | |
| 310 | pthread_mutex_lock(<t_transport_mutex); |
| 311 | cds_list_for_each_entry(tran_iter, <t_transport_list, node) { |
| 312 | if (!strcmp(tran_iter->name, trace_type)) { |
| 313 | transport = tran_iter; |
| 314 | break; |
| 315 | } |
| 316 | } |
| 317 | pthread_mutex_unlock(<t_transport_mutex); |
| 318 | |
| 319 | if (!transport) { |
| 320 | ERR("Transport %s is not present", trace_type); |
| 321 | err = -EINVAL; |
| 322 | goto traces_error; |
| 323 | } |
| 324 | |
| 325 | trace->transport = transport; |
| 326 | |
| 327 | traces_error: |
| 328 | ltt_unlock_traces(); |
| 329 | return err; |
| 330 | } |
| 331 | |
| 332 | int ltt_trace_set_channel_subbufsize(const char *trace_name, |
| 333 | const char *channel_name, unsigned int size) |
| 334 | { |
| 335 | int err = 0; |
| 336 | struct ust_trace *trace; |
| 337 | int index; |
| 338 | |
| 339 | ltt_lock_traces(); |
| 340 | |
| 341 | trace = _ltt_trace_find_setup(trace_name); |
| 342 | if (!trace) { |
| 343 | ERR("Trace not found %s", trace_name); |
| 344 | err = -ENOENT; |
| 345 | goto traces_error; |
| 346 | } |
| 347 | |
| 348 | index = ltt_channels_get_index_from_name(channel_name); |
| 349 | if (index < 0) { |
| 350 | ERR("Channel %s not found", channel_name); |
| 351 | err = -ENOENT; |
| 352 | goto traces_error; |
| 353 | } |
| 354 | trace->channels[index].subbuf_size = size; |
| 355 | |
| 356 | traces_error: |
| 357 | ltt_unlock_traces(); |
| 358 | return err; |
| 359 | } |
| 360 | |
| 361 | int ltt_trace_set_channel_subbufcount(const char *trace_name, |
| 362 | const char *channel_name, unsigned int cnt) |
| 363 | { |
| 364 | int err = 0; |
| 365 | struct ust_trace *trace; |
| 366 | int index; |
| 367 | |
| 368 | ltt_lock_traces(); |
| 369 | |
| 370 | trace = _ltt_trace_find_setup(trace_name); |
| 371 | if (!trace) { |
| 372 | ERR("Trace not found %s", trace_name); |
| 373 | err = -ENOENT; |
| 374 | goto traces_error; |
| 375 | } |
| 376 | |
| 377 | index = ltt_channels_get_index_from_name(channel_name); |
| 378 | if (index < 0) { |
| 379 | ERR("Channel %s not found", channel_name); |
| 380 | err = -ENOENT; |
| 381 | goto traces_error; |
| 382 | } |
| 383 | trace->channels[index].subbuf_cnt = cnt; |
| 384 | |
| 385 | traces_error: |
| 386 | ltt_unlock_traces(); |
| 387 | return err; |
| 388 | } |
| 389 | |
| 390 | int ltt_trace_set_channel_enable(const char *trace_name, |
| 391 | const char *channel_name, unsigned int enable) |
| 392 | { |
| 393 | int err = 0; |
| 394 | struct ust_trace *trace; |
| 395 | int index; |
| 396 | |
| 397 | ltt_lock_traces(); |
| 398 | |
| 399 | trace = _ltt_trace_find_setup(trace_name); |
| 400 | if (!trace) { |
| 401 | ERR("Trace not found %s", trace_name); |
| 402 | err = -ENOENT; |
| 403 | goto traces_error; |
| 404 | } |
| 405 | |
| 406 | /* |
| 407 | * Datas in metadata channel(marker info) is necessary to be able to |
| 408 | * read the trace, we always enable this channel. |
| 409 | */ |
| 410 | if (!enable && !strcmp(channel_name, "metadata")) { |
| 411 | ERR("Trying to disable metadata channel"); |
| 412 | err = -EINVAL; |
| 413 | goto traces_error; |
| 414 | } |
| 415 | |
| 416 | index = ltt_channels_get_index_from_name(channel_name); |
| 417 | if (index < 0) { |
| 418 | ERR("Channel %s not found", channel_name); |
| 419 | err = -ENOENT; |
| 420 | goto traces_error; |
| 421 | } |
| 422 | |
| 423 | trace->channels[index].active = enable; |
| 424 | |
| 425 | traces_error: |
| 426 | ltt_unlock_traces(); |
| 427 | return err; |
| 428 | } |
| 429 | |
| 430 | int ltt_trace_set_channel_overwrite(const char *trace_name, |
| 431 | const char *channel_name, unsigned int overwrite) |
| 432 | { |
| 433 | int err = 0; |
| 434 | struct ust_trace *trace; |
| 435 | int index; |
| 436 | |
| 437 | ltt_lock_traces(); |
| 438 | |
| 439 | trace = _ltt_trace_find_setup(trace_name); |
| 440 | if (!trace) { |
| 441 | ERR("Trace not found %s", trace_name); |
| 442 | err = -ENOENT; |
| 443 | goto traces_error; |
| 444 | } |
| 445 | |
| 446 | /* |
| 447 | * Always put the metadata channel in non-overwrite mode : |
| 448 | * This is a very low traffic channel and it can't afford to have its |
| 449 | * data overwritten : this data (marker info) is necessary to be |
| 450 | * able to read the trace. |
| 451 | */ |
| 452 | if (overwrite && !strcmp(channel_name, "metadata")) { |
| 453 | ERR("Trying to set metadata channel to overwrite mode"); |
| 454 | err = -EINVAL; |
| 455 | goto traces_error; |
| 456 | } |
| 457 | |
| 458 | index = ltt_channels_get_index_from_name(channel_name); |
| 459 | if (index < 0) { |
| 460 | ERR("Channel %s not found", channel_name); |
| 461 | err = -ENOENT; |
| 462 | goto traces_error; |
| 463 | } |
| 464 | |
| 465 | trace->channels[index].overwrite = overwrite; |
| 466 | |
| 467 | traces_error: |
| 468 | ltt_unlock_traces(); |
| 469 | return err; |
| 470 | } |
| 471 | |
| 472 | int ltt_trace_alloc(const char *trace_name) |
| 473 | { |
| 474 | int err = 0; |
| 475 | struct ust_trace *trace; |
| 476 | unsigned int subbuf_size, subbuf_cnt; |
| 477 | int chan; |
| 478 | const char *channel_name; |
| 479 | |
| 480 | ltt_lock_traces(); |
| 481 | |
| 482 | if (_ltt_trace_find(trace_name)) { /* Trace already allocated */ |
| 483 | err = 1; |
| 484 | goto traces_error; |
| 485 | } |
| 486 | |
| 487 | trace = _ltt_trace_find_setup(trace_name); |
| 488 | if (!trace) { |
| 489 | ERR("Trace not found %s", trace_name); |
| 490 | err = -ENOENT; |
| 491 | goto traces_error; |
| 492 | } |
| 493 | |
| 494 | urcu_ref_init(&trace->urcu_ref); |
| 495 | urcu_ref_init(&trace->ltt_transport_urcu_ref); |
| 496 | trace->active = 0; |
| 497 | trace->freq_scale = trace_clock_freq_scale(); |
| 498 | |
| 499 | if (!trace->transport) { |
| 500 | ERR("Transport is not set"); |
| 501 | err = -EINVAL; |
| 502 | goto transport_error; |
| 503 | } |
| 504 | trace->ops = &trace->transport->ops; |
| 505 | |
| 506 | trace->start_freq = trace_clock_frequency(); |
| 507 | trace->start_tsc = trace_clock_read64(); |
| 508 | gettimeofday(&trace->start_time, NULL); //ust// changed /* FIXME: is this ok? */ |
| 509 | |
| 510 | for (chan = 0; chan < trace->nr_channels; chan++) { |
| 511 | if (!(trace->channels[chan].active)) |
| 512 | continue; |
| 513 | |
| 514 | channel_name = ltt_channels_get_name_from_index(chan); |
| 515 | WARN_ON(!channel_name); |
| 516 | subbuf_size = trace->channels[chan].subbuf_size; |
| 517 | subbuf_cnt = trace->channels[chan].subbuf_cnt; |
| 518 | prepare_chan_size_num(&subbuf_size, &subbuf_cnt); |
| 519 | err = trace->ops->create_channel(trace_name, trace, |
| 520 | channel_name, |
| 521 | &trace->channels[chan], |
| 522 | subbuf_size, |
| 523 | subbuf_cnt, |
| 524 | trace->channels[chan].overwrite); |
| 525 | if (err != 0) { |
| 526 | ERR("Cannot create channel %s", channel_name); |
| 527 | goto create_channel_error; |
| 528 | } |
| 529 | } |
| 530 | |
| 531 | cds_list_del(&trace->list); |
| 532 | cds_list_add_rcu(&trace->list, <t_traces.head); |
| 533 | |
| 534 | ltt_unlock_traces(); |
| 535 | |
| 536 | return 0; |
| 537 | |
| 538 | create_channel_error: |
| 539 | for (chan--; chan >= 0; chan--) |
| 540 | if (trace->channels[chan].active) |
| 541 | trace->ops->remove_channel(&trace->channels[chan]); |
| 542 | |
| 543 | transport_error: |
| 544 | traces_error: |
| 545 | ltt_unlock_traces(); |
| 546 | return err; |
| 547 | } |
| 548 | |
| 549 | /* Must be called while sure that trace is in the list. */ |
| 550 | static int _ltt_trace_destroy(struct ust_trace *trace) |
| 551 | { |
| 552 | int err = -EPERM; |
| 553 | |
| 554 | if (trace == NULL) { |
| 555 | err = -ENOENT; |
| 556 | goto traces_error; |
| 557 | } |
| 558 | if (trace->active) { |
| 559 | ERR("Can't destroy trace %s : tracer is active", trace->trace_name); |
| 560 | err = -EBUSY; |
| 561 | goto active_error; |
| 562 | } |
| 563 | |
| 564 | cds_list_del_rcu(&trace->list); |
| 565 | synchronize_rcu(); |
| 566 | |
| 567 | return 0; |
| 568 | |
| 569 | active_error: |
| 570 | traces_error: |
| 571 | return err; |
| 572 | } |
| 573 | |
| 574 | /* Sleepable part of the destroy */ |
| 575 | static void __ltt_trace_destroy(struct ust_trace *trace, int drop) |
| 576 | { |
| 577 | int i; |
| 578 | struct ust_channel *chan; |
| 579 | |
| 580 | if(!drop) { |
| 581 | for (i = 0; i < trace->nr_channels; i++) { |
| 582 | chan = &trace->channels[i]; |
| 583 | if (chan->active) |
| 584 | trace->ops->finish_channel(chan); |
| 585 | } |
| 586 | } |
| 587 | |
| 588 | /* |
| 589 | * The currently destroyed trace is not in the trace list anymore, |
| 590 | * so it's safe to call the async wakeup ourself. It will deliver |
| 591 | * the last subbuffers. |
| 592 | */ |
| 593 | trace_async_wakeup(trace); |
| 594 | |
| 595 | for (i = 0; i < trace->nr_channels; i++) { |
| 596 | chan = &trace->channels[i]; |
| 597 | if (chan->active) |
| 598 | trace->ops->remove_channel(chan); |
| 599 | } |
| 600 | |
| 601 | urcu_ref_put(&trace->ltt_transport_urcu_ref, ltt_release_transport); |
| 602 | |
| 603 | urcu_ref_put(&trace->urcu_ref, ltt_release_trace); |
| 604 | } |
| 605 | |
| 606 | int ltt_trace_destroy(const char *trace_name, int drop) |
| 607 | { |
| 608 | int err = 0; |
| 609 | struct ust_trace *trace; |
| 610 | |
| 611 | ltt_lock_traces(); |
| 612 | |
| 613 | trace = _ltt_trace_find(trace_name); |
| 614 | if (trace) { |
| 615 | err = _ltt_trace_destroy(trace); |
| 616 | if (err) |
| 617 | goto error; |
| 618 | |
| 619 | ltt_unlock_traces(); |
| 620 | |
| 621 | __ltt_trace_destroy(trace, drop); |
| 622 | |
| 623 | return 0; |
| 624 | } |
| 625 | |
| 626 | trace = _ltt_trace_find_setup(trace_name); |
| 627 | if (trace) { |
| 628 | _ltt_trace_free(trace); |
| 629 | ltt_unlock_traces(); |
| 630 | return 0; |
| 631 | } |
| 632 | |
| 633 | err = -ENOENT; |
| 634 | |
| 635 | error: |
| 636 | ltt_unlock_traces(); |
| 637 | return err; |
| 638 | } |
| 639 | |
| 640 | /* must be called from within a traces lock. */ |
| 641 | static int _ltt_trace_start(struct ust_trace *trace) |
| 642 | { |
| 643 | int err = 0; |
| 644 | |
| 645 | if (trace == NULL) { |
| 646 | err = -ENOENT; |
| 647 | goto traces_error; |
| 648 | } |
| 649 | if (trace->active) |
| 650 | DBG("Tracing already active for trace %s", trace->trace_name); |
| 651 | trace->active = 1; |
| 652 | /* Read by trace points without protection : be careful */ |
| 653 | ltt_traces.num_active_traces++; |
| 654 | return err; |
| 655 | |
| 656 | traces_error: |
| 657 | return err; |
| 658 | } |
| 659 | |
| 660 | int ltt_trace_start(const char *trace_name) |
| 661 | { |
| 662 | int err = 0; |
| 663 | struct ust_trace *trace; |
| 664 | |
| 665 | ltt_lock_traces(); |
| 666 | |
| 667 | trace = _ltt_trace_find(trace_name); |
| 668 | err = _ltt_trace_start(trace); |
| 669 | if (err) |
| 670 | goto no_trace; |
| 671 | |
| 672 | ltt_unlock_traces(); |
| 673 | |
| 674 | /* |
| 675 | * Call the process-wide state dump. |
| 676 | * Notice that there is no protection on the trace : that's exactly |
| 677 | * why we iterate on the list and check for trace equality instead of |
| 678 | * directly using this trace handle inside the logging function: we want |
| 679 | * to record events only in a single trace in the trace session list. |
| 680 | */ |
| 681 | |
| 682 | ltt_dump_marker_state(trace); |
| 683 | |
| 684 | return err; |
| 685 | |
| 686 | /* Error handling */ |
| 687 | no_trace: |
| 688 | ltt_unlock_traces(); |
| 689 | return err; |
| 690 | } |
| 691 | |
| 692 | /* must be called from within traces lock */ |
| 693 | static int _ltt_trace_stop(struct ust_trace *trace) |
| 694 | { |
| 695 | int err = -EPERM; |
| 696 | |
| 697 | if (trace == NULL) { |
| 698 | err = -ENOENT; |
| 699 | goto traces_error; |
| 700 | } |
| 701 | if (!trace->active) |
| 702 | DBG("LTT : Tracing not active for trace %s", trace->trace_name); |
| 703 | if (trace->active) { |
| 704 | trace->active = 0; |
| 705 | ltt_traces.num_active_traces--; |
| 706 | } |
| 707 | return 0; |
| 708 | |
| 709 | traces_error: |
| 710 | return err; |
| 711 | } |
| 712 | |
| 713 | int ltt_trace_stop(const char *trace_name) |
| 714 | { |
| 715 | int err = 0; |
| 716 | struct ust_trace *trace; |
| 717 | |
| 718 | ltt_lock_traces(); |
| 719 | trace = _ltt_trace_find(trace_name); |
| 720 | err = _ltt_trace_stop(trace); |
| 721 | ltt_unlock_traces(); |
| 722 | return err; |
| 723 | } |