libust/tracer.c

   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 //ust// static void async_wakeup(unsigned long data);
  44 //ust//
  45 //ust// static DEFINE_TIMER(ltt_async_wakeup_timer, async_wakeup, 0, 0);
  46
  47 /* Default callbacks for modules */
  48 notrace int ltt_filter_control_default(enum ltt_filter_control_msg msg,
  49                 struct ust_trace *trace)
  50 {
  51         return 0;
  52 }
  53
  54 int ltt_statedump_default(struct ust_trace *trace)
  55 {
  56         return 0;
  57 }
  58
  59 /* Callbacks for registered modules */
  60
  61 int (*ltt_filter_control_functor)
  62         (enum ltt_filter_control_msg msg, struct ust_trace *trace) =
  63                                         ltt_filter_control_default;
  64 struct module *ltt_filter_control_owner;
  65
  66 /* These function pointers are protected by a trace activation check */
  67 struct module *ltt_run_filter_owner;
  68 int (*ltt_statedump_functor)(struct ust_trace *trace) =
  69                                         ltt_statedump_default;
  70 struct module *ltt_statedump_owner;
  71
  72 struct chan_info_struct chan_infos[] = {
  73         [LTT_CHANNEL_METADATA] = {
  74                 LTT_METADATA_CHANNEL,
  75                 LTT_DEFAULT_SUBBUF_SIZE_LOW,
  76                 LTT_DEFAULT_N_SUBBUFS_LOW,
  77         },
  78         [LTT_CHANNEL_UST] = {
  79                 LTT_UST_CHANNEL,
  80                 LTT_DEFAULT_SUBBUF_SIZE_HIGH,
  81                 LTT_DEFAULT_N_SUBBUFS_HIGH,
  82         },
  83 };
  84
  85 static enum ltt_channels get_channel_type_from_name(const char *name)
  86 {
  87         int i;
  88
  89         if (!name)
  90                 return LTT_CHANNEL_UST;
  91
  92         for (i = 0; i < ARRAY_SIZE(chan_infos); i++)
  93                 if (chan_infos[i].name && !strcmp(name, chan_infos[i].name))
  94                         return (enum ltt_channels)i;
  95
  96         return LTT_CHANNEL_UST;
  97 }
  98
  99 /**
 100  * ltt_module_register - LTT module registration
 101  * @name: module type
 102  * @function: callback to register
 103  * @owner: module which owns the callback
 104  *
 105  * The module calling this registration function must ensure that no
 106  * trap-inducing code will be executed by "function". E.g. vmalloc_sync_all()
 107  * must be called between a vmalloc and the moment the memory is made visible to
 108  * "function". This registration acts as a vmalloc_sync_all. Therefore, only if
 109  * the module allocates virtual memory after its registration must it
 110  * synchronize the TLBs.
 111  */
 112 //ust// int ltt_module_register(enum ltt_module_function name, void *function,
 113 //ust//                 struct module *owner)
 114 //ust// {
 115 //ust//         int ret = 0;
 116 //ust//
 117 //ust//         /*
 118 //ust//          * Make sure no page fault can be triggered by the module about to be
 119 //ust//          * registered. We deal with this here so we don't have to call
 120 //ust//          * vmalloc_sync_all() in each module's init.
 121 //ust//          */
 122 //ust//         vmalloc_sync_all();
 123 //ust//
 124 //ust//         switch (name) {
 125 //ust//         case LTT_FUNCTION_RUN_FILTER:
 126 //ust//                 if (ltt_run_filter_owner != NULL) {
 127 //ust//                         ret = -EEXIST;
 128 //ust//                         goto end;
 129 //ust//                 }
 130 //ust//                 ltt_filter_register((ltt_run_filter_functor)function);
 131 //ust//                 ltt_run_filter_owner = owner;
 132 //ust//                 break;
 133 //ust//         case LTT_FUNCTION_FILTER_CONTROL:
 134 //ust//                 if (ltt_filter_control_owner != NULL) {
 135 //ust//                         ret = -EEXIST;
 136 //ust//                         goto end;
 137 //ust//                 }
 138 //ust//                 ltt_filter_control_functor =
 139 //ust//                         (int (*)(enum ltt_filter_control_msg,
 140 //ust//                         struct ust_trace *))function;
 141 //ust//                 ltt_filter_control_owner = owner;
 142 //ust//                 break;
 143 //ust//         case LTT_FUNCTION_STATEDUMP:
 144 //ust//                 if (ltt_statedump_owner != NULL) {
 145 //ust//                         ret = -EEXIST;
 146 //ust//                         goto end;
 147 //ust//                 }
 148 //ust//                 ltt_statedump_functor =
 149 //ust//                         (int (*)(struct ust_trace *))function;
 150 //ust//                 ltt_statedump_owner = owner;
 151 //ust//                 break;
 152 //ust//         }
 153 //ust//
 154 //ust// end:
 155 //ust//
 156 //ust//         return ret;
 157 //ust// }
 158
 159 /**
 160  * ltt_module_unregister - LTT module unregistration
 161  * @name: module type
 162  */
 163 //ust// void ltt_module_unregister(enum ltt_module_function name)
 164 //ust// {
 165 //ust//         switch (name) {
 166 //ust//         case LTT_FUNCTION_RUN_FILTER:
 167 //ust//                 ltt_filter_unregister();
 168 //ust//                 ltt_run_filter_owner = NULL;
 169 //ust//                 /* Wait for preempt sections to finish */
 170 //ust//                 synchronize_sched();
 171 //ust//                 break;
 172 //ust//         case LTT_FUNCTION_FILTER_CONTROL:
 173 //ust//                 ltt_filter_control_functor = ltt_filter_control_default;
 174 //ust//                 ltt_filter_control_owner = NULL;
 175 //ust//                 break;
 176 //ust//         case LTT_FUNCTION_STATEDUMP:
 177 //ust//                 ltt_statedump_functor = ltt_statedump_default;
 178 //ust//                 ltt_statedump_owner = NULL;
 179 //ust//                 break;
 180 //ust//         }
 181 //ust//
 182 //ust// }
 183
 184 static CDS_LIST_HEAD(ltt_transport_list);
 185
 186 /**
 187  * ltt_transport_register - LTT transport registration
 188  * @transport: transport structure
 189  *
 190  * Registers a transport which can be used as output to extract the data out of
 191  * LTTng. The module calling this registration function must ensure that no
 192  * trap-inducing code will be executed by the transport functions. E.g.
 193  * vmalloc_sync_all() must be called between a vmalloc and the moment the memory
 194  * is made visible to the transport function. This registration acts as a
 195  * vmalloc_sync_all. Therefore, only if the module allocates virtual memory
 196  * after its registration must it synchronize the TLBs.
 197  */
 198 void ltt_transport_register(struct ltt_transport *transport)
 199 {
 200         /*
 201          * Make sure no page fault can be triggered by the module about to be
 202          * registered. We deal with this here so we don't have to call
 203          * vmalloc_sync_all() in each module's init.
 204          */
 205 //ust// vmalloc_sync_all();
 206
 207         ltt_lock_traces();
 208         cds_list_add_tail(&transport->node, &ltt_transport_list);
 209         ltt_unlock_traces();
 210 }
 211
 212 /**
 213  * ltt_transport_unregister - LTT transport unregistration
 214  * @transport: transport structure
 215  */
 216 void ltt_transport_unregister(struct ltt_transport *transport)
 217 {
 218         ltt_lock_traces();
 219         cds_list_del(&transport->node);
 220         ltt_unlock_traces();
 221 }
 222
 223 static inline int is_channel_overwrite(enum ltt_channels chan,
 224         enum trace_mode mode)
 225 {
 226         switch (mode) {
 227         case LTT_TRACE_NORMAL:
 228                 return 0;
 229         case LTT_TRACE_FLIGHT:
 230                 switch (chan) {
 231                 case LTT_CHANNEL_METADATA:
 232                         return 0;
 233                 default:
 234                         return 1;
 235                 }
 236         case LTT_TRACE_HYBRID:
 237                 switch (chan) {
 238                 case LTT_CHANNEL_METADATA:
 239                         return 0;
 240                 default:
 241                         return 1;
 242                 }
 243         default:
 244                 return 0;
 245         }
 246 }
 247
 248 static void trace_async_wakeup(struct ust_trace *trace)
 249 {
 250         int i;
 251         struct ust_channel *chan;
 252
 253         /* Must check each channel for pending read wakeup */
 254         for (i = 0; i < trace->nr_channels; i++) {
 255                 chan = &trace->channels[i];
 256                 if (chan->active)
 257                         trace->ops->wakeup_channel(chan);
 258         }
 259 }
 260
 261 //ust// /* Timer to send async wakeups to the readers */
 262 //ust// static void async_wakeup(unsigned long data)
 263 //ust// {
 264 //ust//         struct ust_trace *trace;
 265 //ust//
 266 //ust//         /*
 267 //ust//          * PREEMPT_RT does not allow spinlocks to be taken within preempt
 268 //ust//          * disable sections (spinlock taken in wake_up). However, mainline won't
 269 //ust//          * allow mutex to be taken in interrupt context. Ugly.
 270 //ust//          * A proper way to do this would be to turn the timer into a
 271 //ust//          * periodically woken up thread, but it adds to the footprint.
 272 //ust//          */
 273 //ust// #ifndef CONFIG_PREEMPT_RT
 274 //ust//         rcu_read_lock_sched();
 275 //ust// #else
 276 //ust//         ltt_lock_traces();
 277 //ust// #endif
 278 //ust//         cds_list_for_each_entry_rcu(trace, &ltt_traces.head, list) {
 279 //ust//                 trace_async_wakeup(trace);
 280 //ust//         }
 281 //ust// #ifndef CONFIG_PREEMPT_RT
 282 //ust//         rcu_read_unlock_sched();
 283 //ust// #else
 284 //ust//         ltt_unlock_traces();
 285 //ust// #endif
 286 //ust//
 287 //ust//         mod_timer(&ltt_async_wakeup_timer, jiffies + LTT_PERCPU_TIMER_INTERVAL);
 288 //ust// }
 289
 290 /**
 291  * _ltt_trace_find - find a trace by given name.
 292  * trace_name: trace name
 293  *
 294  * Returns a pointer to the trace structure, NULL if not found.
 295  */
 296 struct ust_trace *_ltt_trace_find(const char *trace_name)
 297 {
 298         struct ust_trace *trace;
 299
 300         cds_list_for_each_entry(trace, &ltt_traces.head, list)
 301                 if (!strncmp(trace->trace_name, trace_name, NAME_MAX))
 302                         return trace;
 303
 304         return NULL;
 305 }
 306
 307 /* _ltt_trace_find_setup :
 308  * find a trace in setup list by given name.
 309  *
 310  * Returns a pointer to the trace structure, NULL if not found.
 311  */
 312 struct ust_trace *_ltt_trace_find_setup(const char *trace_name)
 313 {
 314         struct ust_trace *trace;
 315
 316         cds_list_for_each_entry(trace, &ltt_traces.setup_head, list)
 317                 if (!strncmp(trace->trace_name, trace_name, NAME_MAX))
 318                         return trace;
 319
 320         return NULL;
 321 }
 322
 323 /**
 324  * ltt_release_transport - Release an LTT transport
 325  * @kref : reference count on the transport
 326  */
 327 void ltt_release_transport(struct kref *kref)
 328 {
 329 //ust//         struct ust_trace *trace = container_of(kref,
 330 //ust//                         struct ust_trace, ltt_transport_kref);
 331 //ust//         trace->ops->remove_dirs(trace);
 332 }
 333
 334 /**
 335  * ltt_release_trace - Release a LTT trace
 336  * @kref : reference count on the trace
 337  */
 338 void ltt_release_trace(struct kref *kref)
 339 {
 340         struct ust_trace *trace = _ust_container_of(kref,
 341                         struct ust_trace, kref);
 342         ltt_channels_trace_free(trace->channels);
 343         free(trace);
 344 }
 345
 346 static inline void prepare_chan_size_num(unsigned int *subbuf_size,
 347                                          unsigned int *n_subbufs)
 348 {
 349         /* Make sure the subbuffer size is larger than a page */
 350         *subbuf_size = max_t(unsigned int, *subbuf_size, PAGE_SIZE);
 351
 352         /* round to next power of 2 */
 353         *subbuf_size = 1 << get_count_order(*subbuf_size);
 354         *n_subbufs = 1 << get_count_order(*n_subbufs);
 355
 356         /* Subbuf size and number must both be power of two */
 357         WARN_ON(hweight32(*subbuf_size) != 1);
 358         WARN_ON(hweight32(*n_subbufs) != 1);
 359 }
 360
 361 int _ltt_trace_setup(const char *trace_name)
 362 {
 363         int err = 0;
 364         struct ust_trace *new_trace = NULL;
 365         int metadata_index;
 366         unsigned int chan;
 367         enum ltt_channels chantype;
 368
 369         if (_ltt_trace_find_setup(trace_name)) {
 370                 ERR("Trace name %s already used", trace_name);
 371                 err = -EEXIST;
 372                 goto traces_error;
 373         }
 374
 375         if (_ltt_trace_find(trace_name)) {
 376                 ERR("Trace name %s already used", trace_name);
 377                 err = -EEXIST;
 378                 goto traces_error;
 379         }
 380
 381         new_trace = zmalloc(sizeof(struct ust_trace));
 382         if (!new_trace) {
 383                 ERR("Unable to allocate memory for trace %s", trace_name);
 384                 err = -ENOMEM;
 385                 goto traces_error;
 386         }
 387         strncpy(new_trace->trace_name, trace_name, NAME_MAX);
 388         new_trace->channels = ltt_channels_trace_alloc(&new_trace->nr_channels,
 389                                 ust_channels_overwrite_by_default,
 390                                 ust_channels_request_collection_by_default, 1);
 391         if (!new_trace->channels) {
 392                 ERR("Unable to allocate memory for chaninfo  %s\n", trace_name);
 393                 err = -ENOMEM;
 394                 goto trace_free;
 395         }
 396
 397         /*
 398          * Force metadata channel to active, no overwrite.
 399          */
 400         metadata_index = ltt_channels_get_index_from_name("metadata");
 401         WARN_ON(metadata_index < 0);
 402         new_trace->channels[metadata_index].overwrite = 0;
 403         new_trace->channels[metadata_index].active = 1;
 404
 405         /*
 406          * Set hardcoded tracer defaults for some channels
 407          */
 408         for (chan = 0; chan < new_trace->nr_channels; chan++) {
 409                 if (!(new_trace->channels[chan].active))
 410                         continue;
 411
 412                 chantype = get_channel_type_from_name(
 413                         ltt_channels_get_name_from_index(chan));
 414                 new_trace->channels[chan].subbuf_size =
 415                         chan_infos[chantype].def_subbufsize;
 416                 new_trace->channels[chan].subbuf_cnt =
 417                         chan_infos[chantype].def_subbufcount;
 418         }
 419
 420         cds_list_add(&new_trace->list, &ltt_traces.setup_head);
 421         return 0;
 422
 423 trace_free:
 424         free(new_trace);
 425 traces_error:
 426         return err;
 427 }
 428
 429
 430 int ltt_trace_setup(const char *trace_name)
 431 {
 432         int ret;
 433         ltt_lock_traces();
 434         ret = _ltt_trace_setup(trace_name);
 435         ltt_unlock_traces();
 436         return ret;
 437 }
 438
 439 /* must be called from within a traces lock. */
 440 static void _ltt_trace_free(struct ust_trace *trace)
 441 {
 442         cds_list_del(&trace->list);
 443         free(trace);
 444 }
 445
 446 int ltt_trace_set_type(const char *trace_name, const char *trace_type)
 447 {
 448         int err = 0;
 449         struct ust_trace *trace;
 450         struct ltt_transport *tran_iter, *transport = NULL;
 451
 452         ltt_lock_traces();
 453
 454         trace = _ltt_trace_find_setup(trace_name);
 455         if (!trace) {
 456                 ERR("Trace not found %s", trace_name);
 457                 err = -ENOENT;
 458                 goto traces_error;
 459         }
 460
 461         cds_list_for_each_entry(tran_iter, &ltt_transport_list, node) {
 462                 if (!strcmp(tran_iter->name, trace_type)) {
 463                         transport = tran_iter;
 464                         break;
 465                 }
 466         }
 467         if (!transport) {
 468                 ERR("Transport %s is not present", trace_type);
 469                 err = -EINVAL;
 470                 goto traces_error;
 471         }
 472
 473         trace->transport = transport;
 474
 475 traces_error:
 476         ltt_unlock_traces();
 477         return err;
 478 }
 479
 480 int ltt_trace_set_channel_subbufsize(const char *trace_name,
 481                 const char *channel_name, unsigned int size)
 482 {
 483         int err = 0;
 484         struct ust_trace *trace;
 485         int index;
 486
 487         ltt_lock_traces();
 488
 489         trace = _ltt_trace_find_setup(trace_name);
 490         if (!trace) {
 491                 ERR("Trace not found %s", trace_name);
 492                 err = -ENOENT;
 493                 goto traces_error;
 494         }
 495
 496         index = ltt_channels_get_index_from_name(channel_name);
 497         if (index < 0) {
 498                 ERR("Channel %s not found", channel_name);
 499                 err = -ENOENT;
 500                 goto traces_error;
 501         }
 502         trace->channels[index].subbuf_size = size;
 503
 504 traces_error:
 505         ltt_unlock_traces();
 506         return err;
 507 }
 508
 509 int ltt_trace_set_channel_subbufcount(const char *trace_name,
 510                 const char *channel_name, unsigned int cnt)
 511 {
 512         int err = 0;
 513         struct ust_trace *trace;
 514         int index;
 515
 516         ltt_lock_traces();
 517
 518         trace = _ltt_trace_find_setup(trace_name);
 519         if (!trace) {
 520                 ERR("Trace not found %s", trace_name);
 521                 err = -ENOENT;
 522                 goto traces_error;
 523         }
 524
 525         index = ltt_channels_get_index_from_name(channel_name);
 526         if (index < 0) {
 527                 ERR("Channel %s not found", channel_name);
 528                 err = -ENOENT;
 529                 goto traces_error;
 530         }
 531         trace->channels[index].subbuf_cnt = cnt;
 532
 533 traces_error:
 534         ltt_unlock_traces();
 535         return err;
 536 }
 537
 538 int ltt_trace_set_channel_enable(const char *trace_name,
 539                 const char *channel_name, unsigned int enable)
 540 {
 541         int err = 0;
 542         struct ust_trace *trace;
 543         int index;
 544
 545         ltt_lock_traces();
 546
 547         trace = _ltt_trace_find_setup(trace_name);
 548         if (!trace) {
 549                 ERR("Trace not found %s", trace_name);
 550                 err = -ENOENT;
 551                 goto traces_error;
 552         }
 553
 554         /*
 555          * Datas in metadata channel(marker info) is necessary to be able to
 556          * read the trace, we always enable this channel.
 557          */
 558         if (!enable && !strcmp(channel_name, "metadata")) {
 559                 ERR("Trying to disable metadata channel");
 560                 err = -EINVAL;
 561                 goto traces_error;
 562         }
 563
 564         index = ltt_channels_get_index_from_name(channel_name);
 565         if (index < 0) {
 566                 ERR("Channel %s not found", channel_name);
 567                 err = -ENOENT;
 568                 goto traces_error;
 569         }
 570
 571         trace->channels[index].active = enable;
 572
 573 traces_error:
 574         ltt_unlock_traces();
 575         return err;
 576 }
 577
 578 int ltt_trace_set_channel_overwrite(const char *trace_name,
 579                 const char *channel_name, unsigned int overwrite)
 580 {
 581         int err = 0;
 582         struct ust_trace *trace;
 583         int index;
 584
 585         ltt_lock_traces();
 586
 587         trace = _ltt_trace_find_setup(trace_name);
 588         if (!trace) {
 589                 ERR("Trace not found %s", trace_name);
 590                 err = -ENOENT;
 591                 goto traces_error;
 592         }
 593
 594         /*
 595          * Always put the metadata channel in non-overwrite mode :
 596          * This is a very low traffic channel and it can't afford to have its
 597          * data overwritten : this data (marker info) is necessary to be
 598          * able to read the trace.
 599          */
 600         if (overwrite && !strcmp(channel_name, "metadata")) {
 601                 ERR("Trying to set metadata channel to overwrite mode");
 602                 err = -EINVAL;
 603                 goto traces_error;
 604         }
 605
 606         index = ltt_channels_get_index_from_name(channel_name);
 607         if (index < 0) {
 608                 ERR("Channel %s not found", channel_name);
 609                 err = -ENOENT;
 610                 goto traces_error;
 611         }
 612
 613         trace->channels[index].overwrite = overwrite;
 614
 615 traces_error:
 616         ltt_unlock_traces();
 617         return err;
 618 }
 619
 620 int ltt_trace_alloc(const char *trace_name)
 621 {
 622         int err = 0;
 623         struct ust_trace *trace;
 624         unsigned int subbuf_size, subbuf_cnt;
 625 //ust// unsigned long flags;
 626         int chan;
 627         const char *channel_name;
 628
 629         ltt_lock_traces();
 630
 631         if (_ltt_trace_find(trace_name)) { /* Trace already allocated */
 632                 err = 1;
 633                 goto traces_error;
 634         }
 635
 636         trace = _ltt_trace_find_setup(trace_name);
 637         if (!trace) {
 638                 ERR("Trace not found %s", trace_name);
 639                 err = -ENOENT;
 640                 goto traces_error;
 641         }
 642
 643         kref_init(&trace->kref);
 644         kref_init(&trace->ltt_transport_kref);
 645 //ust// init_waitqueue_head(&trace->kref_wq);
 646         trace->active = 0;
 647 //ust// get_trace_clock();
 648         trace->freq_scale = trace_clock_freq_scale();
 649
 650         if (!trace->transport) {
 651                 ERR("Transport is not set");
 652                 err = -EINVAL;
 653                 goto transport_error;
 654         }
 655 //ust// if (!try_module_get(trace->transport->owner)) {
 656 //ust//         ERR("Can't lock transport module");
 657 //ust//         err = -ENODEV;
 658 //ust//         goto transport_error;
 659 //ust// }
 660         trace->ops = &trace->transport->ops;
 661
 662 //ust// err = trace->ops->create_dirs(trace);
 663 //ust// if (err) {
 664 //ust//         ERR("Can't create dir for trace %s", trace_name);
 665 //ust//         goto dirs_error;
 666 //ust// }
 667
 668 //ust// local_irq_save(flags);
 669         trace->start_freq = trace_clock_frequency();
 670         trace->start_tsc = trace_clock_read64();
 671         gettimeofday(&trace->start_time, NULL); //ust// changed /* FIXME: is this ok? */
 672 //ust// local_irq_restore(flags);
 673
 674         for (chan = 0; chan < trace->nr_channels; chan++) {
 675                 if (!(trace->channels[chan].active))
 676                         continue;
 677
 678                 channel_name = ltt_channels_get_name_from_index(chan);
 679                 WARN_ON(!channel_name);
 680                 subbuf_size = trace->channels[chan].subbuf_size;
 681                 subbuf_cnt = trace->channels[chan].subbuf_cnt;
 682                 prepare_chan_size_num(&subbuf_size, &subbuf_cnt);
 683                 err = trace->ops->create_channel(trace_name, trace,
 684                                 channel_name,
 685                                 &trace->channels[chan],
 686                                 subbuf_size,
 687                                 subbuf_cnt,
 688                                 trace->channels[chan].overwrite);
 689                 if (err != 0) {
 690                         ERR("Cannot create channel %s", channel_name);
 691                         goto create_channel_error;
 692                 }
 693         }
 694
 695         cds_list_del(&trace->list);
 696 //ust// if (cds_list_empty(&ltt_traces.head)) {
 697 //ust//         mod_timer(&ltt_async_wakeup_timer,
 698 //ust//                         jiffies + LTT_PERCPU_TIMER_INTERVAL);
 699 //ust//         set_kernel_trace_flag_all_tasks();
 700 //ust// }
 701         cds_list_add_rcu(&trace->list, &ltt_traces.head);
 702 //ust// synchronize_sched();
 703
 704         ltt_unlock_traces();
 705
 706         return 0;
 707
 708 create_channel_error:
 709         for (chan--; chan >= 0; chan--)
 710                 if (trace->channels[chan].active)
 711                         trace->ops->remove_channel(&trace->channels[chan]);
 712
 713 //ust// dirs_error:
 714 //ust// module_put(trace->transport->owner);
 715 transport_error:
 716 //ust// put_trace_clock();
 717 traces_error:
 718         ltt_unlock_traces();
 719         return err;
 720 }
 721
 722 /*
 723  * It is worked as a wrapper for current version of ltt_control.ko.
 724  * We will make a new ltt_control based on debugfs, and control each channel's
 725  * buffer.
 726  */
 727 //ust// static int ltt_trace_create(const char *trace_name, const char *trace_type,
 728 //ust//                 enum trace_mode mode,
 729 //ust//                 unsigned int subbuf_size_low, unsigned int n_subbufs_low,
 730 //ust//                 unsigned int subbuf_size_med, unsigned int n_subbufs_med,
 731 //ust//                 unsigned int subbuf_size_high, unsigned int n_subbufs_high)
 732 //ust// {
 733 //ust//         int err = 0;
 734 //ust//
 735 //ust//         err = ltt_trace_setup(trace_name);
 736 //ust//         if (IS_ERR_VALUE(err))
 737 //ust//                 return err;
 738 //ust//
 739 //ust//         err = ltt_trace_set_type(trace_name, trace_type);
 740 //ust//         if (IS_ERR_VALUE(err))
 741 //ust//                 return err;
 742 //ust//
 743 //ust//         err = ltt_trace_alloc(trace_name);
 744 //ust//         if (IS_ERR_VALUE(err))
 745 //ust//                 return err;
 746 //ust//
 747 //ust//         return err;
 748 //ust// }
 749
 750 /* Must be called while sure that trace is in the list. */
 751 static int _ltt_trace_destroy(struct ust_trace *trace)
 752 {
 753         int err = -EPERM;
 754
 755         if (trace == NULL) {
 756                 err = -ENOENT;
 757                 goto traces_error;
 758         }
 759         if (trace->active) {
 760                 ERR("Can't destroy trace %s : tracer is active", trace->trace_name);
 761                 err = -EBUSY;
 762                 goto active_error;
 763         }
 764         /* Everything went fine */
 765         cds_list_del_rcu(&trace->list);
 766         synchronize_rcu();
 767         if (cds_list_empty(&ltt_traces.head)) {
 768 //ust//         clear_kernel_trace_flag_all_tasks();
 769                 /*
 770                  * We stop the asynchronous delivery of reader wakeup, but
 771                  * we must make one last check for reader wakeups pending
 772                  * later in __ltt_trace_destroy.
 773                  */
 774 //ust//         del_timer_sync(&ltt_async_wakeup_timer);
 775         }
 776         return 0;
 777
 778         /* error handling */
 779 active_error:
 780 traces_error:
 781         return err;
 782 }
 783
 784 /* Sleepable part of the destroy */
 785 static void __ltt_trace_destroy(struct ust_trace *trace, int drop)
 786 {
 787         int i;
 788         struct ust_channel *chan;
 789
 790         if(!drop) {
 791                 for (i = 0; i < trace->nr_channels; i++) {
 792                         chan = &trace->channels[i];
 793                         if (chan->active)
 794                                 trace->ops->finish_channel(chan);
 795                 }
 796         }
 797
 798         return; /* FIXME: temporary for ust */
 799 //ust// flush_scheduled_work();
 800
 801         /*
 802          * The currently destroyed trace is not in the trace list anymore,
 803          * so it's safe to call the async wakeup ourself. It will deliver
 804          * the last subbuffers.
 805          */
 806         trace_async_wakeup(trace);
 807
 808         for (i = 0; i < trace->nr_channels; i++) {
 809                 chan = &trace->channels[i];
 810                 if (chan->active)
 811                         trace->ops->remove_channel(chan);
 812         }
 813
 814         kref_put(&trace->ltt_transport_kref, ltt_release_transport);
 815
 816 //ust// module_put(trace->transport->owner);
 817
 818         /*
 819          * Wait for lttd readers to release the files, therefore making sure
 820          * the last subbuffers have been read.
 821          */
 822 //ust// if (atomic_read(&trace->kref.refcount) > 1) {
 823 //ust//         int ret = 0;
 824 //ust//         __wait_event_interruptible(trace->kref_wq,
 825 //ust//                 (atomic_read(&trace->kref.refcount) == 1), ret);
 826 //ust// }
 827         kref_put(&trace->kref, ltt_release_trace);
 828 }
 829
 830 int ltt_trace_destroy(const char *trace_name, int drop)
 831 {
 832         int err = 0;
 833         struct ust_trace *trace;
 834
 835         ltt_lock_traces();
 836
 837         trace = _ltt_trace_find(trace_name);
 838         if (trace) {
 839                 err = _ltt_trace_destroy(trace);
 840                 if (err)
 841                         goto error;
 842
 843                 ltt_unlock_traces();
 844
 845                 __ltt_trace_destroy(trace, drop);
 846 //ust//         put_trace_clock();
 847
 848                 return 0;
 849         }
 850
 851         trace = _ltt_trace_find_setup(trace_name);
 852         if (trace) {
 853                 _ltt_trace_free(trace);
 854                 ltt_unlock_traces();
 855                 return 0;
 856         }
 857
 858         err = -ENOENT;
 859
 860         /* Error handling */
 861 error:
 862         ltt_unlock_traces();
 863         return err;
 864 }
 865
 866 /* must be called from within a traces lock. */
 867 static int _ltt_trace_start(struct ust_trace *trace)
 868 {
 869         int err = 0;
 870
 871         if (trace == NULL) {
 872                 err = -ENOENT;
 873                 goto traces_error;
 874         }
 875         if (trace->active)
 876                 DBG("Tracing already active for trace %s", trace->trace_name);
 877 //ust// if (!try_module_get(ltt_run_filter_owner)) {
 878 //ust//         err = -ENODEV;
 879 //ust//         ERR("Cannot lock filter module");
 880 //ust//         goto get_ltt_run_filter_error;
 881 //ust// }
 882         trace->active = 1;
 883         /* Read by trace points without protection : be careful */
 884         ltt_traces.num_active_traces++;
 885         return err;
 886
 887         /* error handling */
 888 //ust// get_ltt_run_filter_error:
 889 traces_error:
 890         return err;
 891 }
 892
 893 int ltt_trace_start(const char *trace_name)
 894 {
 895         int err = 0;
 896         struct ust_trace *trace;
 897
 898         ltt_lock_traces();
 899
 900         trace = _ltt_trace_find(trace_name);
 901         err = _ltt_trace_start(trace);
 902         if (err)
 903                 goto no_trace;
 904
 905         ltt_unlock_traces();
 906
 907         /*
 908          * Call the kernel state dump.
 909          * Events will be mixed with real kernel events, it's ok.
 910          * Notice that there is no protection on the trace : that's exactly
 911          * why we iterate on the list and check for trace equality instead of
 912          * directly using this trace handle inside the logging function.
 913          */
 914
 915         ltt_dump_marker_state(trace);
 916
 917 //ust// if (!try_module_get(ltt_statedump_owner)) {
 918 //ust//         err = -ENODEV;
 919 //ust//         ERR("Cannot lock state dump module");
 920 //ust// } else {
 921                 ltt_statedump_functor(trace);
 922 //ust//         module_put(ltt_statedump_owner);
 923 //ust// }
 924
 925         return err;
 926
 927         /* Error handling */
 928 no_trace:
 929         ltt_unlock_traces();
 930         return err;
 931 }
 932
 933 /* must be called from within traces lock */
 934 static int _ltt_trace_stop(struct ust_trace *trace)
 935 {
 936         int err = -EPERM;
 937
 938         if (trace == NULL) {
 939                 err = -ENOENT;
 940                 goto traces_error;
 941         }
 942         if (!trace->active)
 943                 DBG("LTT : Tracing not active for trace %s", trace->trace_name);
 944         if (trace->active) {
 945                 trace->active = 0;
 946                 ltt_traces.num_active_traces--;
 947 //ust//         synchronize_sched(); /* Wait for each tracing to be finished */
 948         }
 949 //ust// module_put(ltt_run_filter_owner);
 950         /* Everything went fine */
 951         return 0;
 952
 953         /* Error handling */
 954 traces_error:
 955         return err;
 956 }
 957
 958 int ltt_trace_stop(const char *trace_name)
 959 {
 960         int err = 0;
 961         struct ust_trace *trace;
 962
 963         ltt_lock_traces();
 964         trace = _ltt_trace_find(trace_name);
 965         err = _ltt_trace_stop(trace);
 966         ltt_unlock_traces();
 967         return err;
 968 }
 969
 970 /**
 971  * ltt_filter_control - Trace filter control in-kernel API
 972  * @msg: Action to perform on the filter
 973  * @trace_name: Trace on which the action must be done
 974  */
 975 int ltt_filter_control(enum ltt_filter_control_msg msg, const char *trace_name)
 976 {
 977         int err;
 978         struct ust_trace *trace;
 979
 980         DBG("ltt_filter_control : trace %s", trace_name);
 981         ltt_lock_traces();
 982         trace = _ltt_trace_find(trace_name);
 983         if (trace == NULL) {
 984                 ERR("Trace does not exist. Cannot proxy control request");
 985                 err = -ENOENT;
 986                 goto trace_error;
 987         }
 988 //ust// if (!try_module_get(ltt_filter_control_owner)) {
 989 //ust//         err = -ENODEV;
 990 //ust//         goto get_module_error;
 991 //ust// }
 992         switch (msg) {
 993         case LTT_FILTER_DEFAULT_ACCEPT:
 994                 DBG("Proxy filter default accept %s", trace_name);
 995                 err = (*ltt_filter_control_functor)(msg, trace);
 996                 break;
 997         case LTT_FILTER_DEFAULT_REJECT:
 998                 DBG("Proxy filter default reject %s", trace_name);
 999                 err = (*ltt_filter_control_functor)(msg, trace);
1000                 break;
1001         default:
1002                 err = -EPERM;
1003         }
1004 //ust// module_put(ltt_filter_control_owner);
1005
1006 //ust// get_module_error:
1007 trace_error:
1008         ltt_unlock_traces();
1009         return err;
1010 }