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/kernelcompat.h>
  38 #include "tracercore.h"
  39 #include "tracer.h"
  40 #include "usterr.h"
  41
  42 //ust// static void async_wakeup(unsigned long data);
  43 //ust//
  44 //ust// static DEFINE_TIMER(ltt_async_wakeup_timer, async_wakeup, 0, 0);
  45
  46 /* Default callbacks for modules */
  47 notrace int ltt_filter_control_default(enum ltt_filter_control_msg msg,
  48                 struct ust_trace *trace)
  49 {
  50         return 0;
  51 }
  52
  53 int ltt_statedump_default(struct ust_trace *trace)
  54 {
  55         return 0;
  56 }
  57
  58 /* Callbacks for registered modules */
  59
  60 int (*ltt_filter_control_functor)
  61         (enum ltt_filter_control_msg msg, struct ust_trace *trace) =
  62                                         ltt_filter_control_default;
  63 struct module *ltt_filter_control_owner;
  64
  65 /* These function pointers are protected by a trace activation check */
  66 struct module *ltt_run_filter_owner;
  67 int (*ltt_statedump_functor)(struct ust_trace *trace) =
  68                                         ltt_statedump_default;
  69 struct module *ltt_statedump_owner;
  70
  71 struct chan_info_struct {
  72         const char *name;
  73         unsigned int def_subbufsize;
  74         unsigned int def_subbufcount;
  75 } chan_infos[] = {
  76         [LTT_CHANNEL_METADATA] = {
  77                 LTT_METADATA_CHANNEL,
  78                 LTT_DEFAULT_SUBBUF_SIZE_LOW,
  79                 LTT_DEFAULT_N_SUBBUFS_LOW,
  80         },
  81         [LTT_CHANNEL_UST] = {
  82                 LTT_UST_CHANNEL,
  83                 LTT_DEFAULT_SUBBUF_SIZE_HIGH,
  84                 LTT_DEFAULT_N_SUBBUFS_HIGH,
  85         },
  86 };
  87
  88 static enum ltt_channels get_channel_type_from_name(const char *name)
  89 {
  90         int i;
  91
  92         if (!name)
  93                 return LTT_CHANNEL_UST;
  94
  95         for (i = 0; i < ARRAY_SIZE(chan_infos); i++)
  96                 if (chan_infos[i].name && !strcmp(name, chan_infos[i].name))
  97                         return (enum ltt_channels)i;
  98
  99         return LTT_CHANNEL_UST;
 100 }
 101
 102 /**
 103  * ltt_module_register - LTT module registration
 104  * @name: module type
 105  * @function: callback to register
 106  * @owner: module which owns the callback
 107  *
 108  * The module calling this registration function must ensure that no
 109  * trap-inducing code will be executed by "function". E.g. vmalloc_sync_all()
 110  * must be called between a vmalloc and the moment the memory is made visible to
 111  * "function". This registration acts as a vmalloc_sync_all. Therefore, only if
 112  * the module allocates virtual memory after its registration must it
 113  * synchronize the TLBs.
 114  */
 115 //ust// int ltt_module_register(enum ltt_module_function name, void *function,
 116 //ust//                 struct module *owner)
 117 //ust// {
 118 //ust//         int ret = 0;
 119 //ust//
 120 //ust//         /*
 121 //ust//          * Make sure no page fault can be triggered by the module about to be
 122 //ust//          * registered. We deal with this here so we don't have to call
 123 //ust//          * vmalloc_sync_all() in each module's init.
 124 //ust//          */
 125 //ust//         vmalloc_sync_all();
 126 //ust//
 127 //ust//         switch (name) {
 128 //ust//         case LTT_FUNCTION_RUN_FILTER:
 129 //ust//                 if (ltt_run_filter_owner != NULL) {
 130 //ust//                         ret = -EEXIST;
 131 //ust//                         goto end;
 132 //ust//                 }
 133 //ust//                 ltt_filter_register((ltt_run_filter_functor)function);
 134 //ust//                 ltt_run_filter_owner = owner;
 135 //ust//                 break;
 136 //ust//         case LTT_FUNCTION_FILTER_CONTROL:
 137 //ust//                 if (ltt_filter_control_owner != NULL) {
 138 //ust//                         ret = -EEXIST;
 139 //ust//                         goto end;
 140 //ust//                 }
 141 //ust//                 ltt_filter_control_functor =
 142 //ust//                         (int (*)(enum ltt_filter_control_msg,
 143 //ust//                         struct ust_trace *))function;
 144 //ust//                 ltt_filter_control_owner = owner;
 145 //ust//                 break;
 146 //ust//         case LTT_FUNCTION_STATEDUMP:
 147 //ust//                 if (ltt_statedump_owner != NULL) {
 148 //ust//                         ret = -EEXIST;
 149 //ust//                         goto end;
 150 //ust//                 }
 151 //ust//                 ltt_statedump_functor =
 152 //ust//                         (int (*)(struct ust_trace *))function;
 153 //ust//                 ltt_statedump_owner = owner;
 154 //ust//                 break;
 155 //ust//         }
 156 //ust//
 157 //ust// end:
 158 //ust//
 159 //ust//         return ret;
 160 //ust// }
 161
 162 /**
 163  * ltt_module_unregister - LTT module unregistration
 164  * @name: module type
 165  */
 166 //ust// void ltt_module_unregister(enum ltt_module_function name)
 167 //ust// {
 168 //ust//         switch (name) {
 169 //ust//         case LTT_FUNCTION_RUN_FILTER:
 170 //ust//                 ltt_filter_unregister();
 171 //ust//                 ltt_run_filter_owner = NULL;
 172 //ust//                 /* Wait for preempt sections to finish */
 173 //ust//                 synchronize_sched();
 174 //ust//                 break;
 175 //ust//         case LTT_FUNCTION_FILTER_CONTROL:
 176 //ust//                 ltt_filter_control_functor = ltt_filter_control_default;
 177 //ust//                 ltt_filter_control_owner = NULL;
 178 //ust//                 break;
 179 //ust//         case LTT_FUNCTION_STATEDUMP:
 180 //ust//                 ltt_statedump_functor = ltt_statedump_default;
 181 //ust//                 ltt_statedump_owner = NULL;
 182 //ust//                 break;
 183 //ust//         }
 184 //ust//
 185 //ust// }
 186
 187 static LIST_HEAD(ltt_transport_list);
 188
 189 /**
 190  * ltt_transport_register - LTT transport registration
 191  * @transport: transport structure
 192  *
 193  * Registers a transport which can be used as output to extract the data out of
 194  * LTTng. The module calling this registration function must ensure that no
 195  * trap-inducing code will be executed by the transport functions. E.g.
 196  * vmalloc_sync_all() must be called between a vmalloc and the moment the memory
 197  * is made visible to the transport function. This registration acts as a
 198  * vmalloc_sync_all. Therefore, only if the module allocates virtual memory
 199  * after its registration must it synchronize the TLBs.
 200  */
 201 void ltt_transport_register(struct ltt_transport *transport)
 202 {
 203         /*
 204          * Make sure no page fault can be triggered by the module about to be
 205          * registered. We deal with this here so we don't have to call
 206          * vmalloc_sync_all() in each module's init.
 207          */
 208 //ust// vmalloc_sync_all();
 209
 210         ltt_lock_traces();
 211         list_add_tail(&transport->node, &ltt_transport_list);
 212         ltt_unlock_traces();
 213 }
 214
 215 /**
 216  * ltt_transport_unregister - LTT transport unregistration
 217  * @transport: transport structure
 218  */
 219 void ltt_transport_unregister(struct ltt_transport *transport)
 220 {
 221         ltt_lock_traces();
 222         list_del(&transport->node);
 223         ltt_unlock_traces();
 224 }
 225
 226 static inline int is_channel_overwrite(enum ltt_channels chan,
 227         enum trace_mode mode)
 228 {
 229         switch (mode) {
 230         case LTT_TRACE_NORMAL:
 231                 return 0;
 232         case LTT_TRACE_FLIGHT:
 233                 switch (chan) {
 234                 case LTT_CHANNEL_METADATA:
 235                         return 0;
 236                 default:
 237                         return 1;
 238                 }
 239         case LTT_TRACE_HYBRID:
 240                 switch (chan) {
 241                 case LTT_CHANNEL_METADATA:
 242                         return 0;
 243                 default:
 244                         return 1;
 245                 }
 246         default:
 247                 return 0;
 248         }
 249 }
 250
 251 static void trace_async_wakeup(struct ust_trace *trace)
 252 {
 253         int i;
 254         struct ust_channel *chan;
 255
 256         /* Must check each channel for pending read wakeup */
 257         for (i = 0; i < trace->nr_channels; i++) {
 258                 chan = &trace->channels[i];
 259                 if (chan->active)
 260                         trace->ops->wakeup_channel(chan);
 261         }
 262 }
 263
 264 //ust// /* Timer to send async wakeups to the readers */
 265 //ust// static void async_wakeup(unsigned long data)
 266 //ust// {
 267 //ust//         struct ust_trace *trace;
 268 //ust//
 269 //ust//         /*
 270 //ust//          * PREEMPT_RT does not allow spinlocks to be taken within preempt
 271 //ust//          * disable sections (spinlock taken in wake_up). However, mainline won't
 272 //ust//          * allow mutex to be taken in interrupt context. Ugly.
 273 //ust//          * A proper way to do this would be to turn the timer into a
 274 //ust//          * periodically woken up thread, but it adds to the footprint.
 275 //ust//          */
 276 //ust// #ifndef CONFIG_PREEMPT_RT
 277 //ust//         rcu_read_lock_sched();
 278 //ust// #else
 279 //ust//         ltt_lock_traces();
 280 //ust// #endif
 281 //ust//         list_for_each_entry_rcu(trace, &ltt_traces.head, list) {
 282 //ust//                 trace_async_wakeup(trace);
 283 //ust//         }
 284 //ust// #ifndef CONFIG_PREEMPT_RT
 285 //ust//         rcu_read_unlock_sched();
 286 //ust// #else
 287 //ust//         ltt_unlock_traces();
 288 //ust// #endif
 289 //ust//
 290 //ust//         mod_timer(&ltt_async_wakeup_timer, jiffies + LTT_PERCPU_TIMER_INTERVAL);
 291 //ust// }
 292
 293 /**
 294  * _ltt_trace_find - find a trace by given name.
 295  * trace_name: trace name
 296  *
 297  * Returns a pointer to the trace structure, NULL if not found.
 298  */
 299 struct ust_trace *_ltt_trace_find(const char *trace_name)
 300 {
 301         struct ust_trace *trace;
 302
 303         list_for_each_entry(trace, &ltt_traces.head, list)
 304                 if (!strncmp(trace->trace_name, trace_name, NAME_MAX))
 305                         return trace;
 306
 307         return NULL;
 308 }
 309
 310 /* _ltt_trace_find_setup :
 311  * find a trace in setup list by given name.
 312  *
 313  * Returns a pointer to the trace structure, NULL if not found.
 314  */
 315 struct ust_trace *_ltt_trace_find_setup(const char *trace_name)
 316 {
 317         struct ust_trace *trace;
 318
 319         list_for_each_entry(trace, &ltt_traces.setup_head, list)
 320                 if (!strncmp(trace->trace_name, trace_name, NAME_MAX))
 321                         return trace;
 322
 323         return NULL;
 324 }
 325
 326 /**
 327  * ltt_release_transport - Release an LTT transport
 328  * @kref : reference count on the transport
 329  */
 330 void ltt_release_transport(struct kref *kref)
 331 {
 332 //ust//         struct ust_trace *trace = container_of(kref,
 333 //ust//                         struct ust_trace, ltt_transport_kref);
 334 //ust//         trace->ops->remove_dirs(trace);
 335 }
 336
 337 /**
 338  * ltt_release_trace - Release a LTT trace
 339  * @kref : reference count on the trace
 340  */
 341 void ltt_release_trace(struct kref *kref)
 342 {
 343         struct ust_trace *trace = container_of(kref,
 344                         struct ust_trace, kref);
 345         ltt_channels_trace_free(trace->channels);
 346         kfree(trace);
 347 }
 348
 349 static inline void prepare_chan_size_num(unsigned int *subbuf_size,
 350                                          unsigned int *n_subbufs)
 351 {
 352         /* Make sure the subbuffer size is larger than a page */
 353         *subbuf_size = max_t(unsigned int, *subbuf_size, PAGE_SIZE);
 354
 355         /* round to next power of 2 */
 356         *subbuf_size = 1 << get_count_order(*subbuf_size);
 357         *n_subbufs = 1 << get_count_order(*n_subbufs);
 358
 359         /* Subbuf size and number must both be power of two */
 360         WARN_ON(hweight32(*subbuf_size) != 1);
 361         WARN_ON(hweight32(*n_subbufs) != 1);
 362 }
 363
 364 int _ltt_trace_setup(const char *trace_name)
 365 {
 366         int err = 0;
 367         struct ust_trace *new_trace = NULL;
 368         int metadata_index;
 369         unsigned int chan;
 370         enum ltt_channels chantype;
 371
 372         if (_ltt_trace_find_setup(trace_name)) {
 373                 ERR("Trace name %s already used", trace_name);
 374                 err = -EEXIST;
 375                 goto traces_error;
 376         }
 377
 378         if (_ltt_trace_find(trace_name)) {
 379                 ERR("Trace name %s already used", trace_name);
 380                 err = -EEXIST;
 381                 goto traces_error;
 382         }
 383
 384         new_trace = kzalloc(sizeof(struct ust_trace), GFP_KERNEL);
 385         if (!new_trace) {
 386                 ERR("Unable to allocate memory for trace %s", trace_name);
 387                 err = -ENOMEM;
 388                 goto traces_error;
 389         }
 390         strncpy(new_trace->trace_name, trace_name, NAME_MAX);
 391         new_trace->channels = ltt_channels_trace_alloc(&new_trace->nr_channels,
 392                                                        0, 1);
 393         if (!new_trace->channels) {
 394                 ERR("Unable to allocate memory for chaninfo  %s\n", trace_name);
 395                 err = -ENOMEM;
 396                 goto trace_free;
 397         }
 398
 399         /*
 400          * Force metadata channel to active, no overwrite.
 401          */
 402         metadata_index = ltt_channels_get_index_from_name("metadata");
 403         WARN_ON(metadata_index < 0);
 404         new_trace->channels[metadata_index].overwrite = 0;
 405         new_trace->channels[metadata_index].active = 1;
 406
 407         /*
 408          * Set hardcoded tracer defaults for some channels
 409          */
 410         for (chan = 0; chan < new_trace->nr_channels; chan++) {
 411                 if (!(new_trace->channels[chan].active))
 412                         continue;
 413
 414                 chantype = get_channel_type_from_name(
 415                         ltt_channels_get_name_from_index(chan));
 416                 new_trace->channels[chan].subbuf_size =
 417                         chan_infos[chantype].def_subbufsize;
 418                 new_trace->channels[chan].subbuf_cnt =
 419                         chan_infos[chantype].def_subbufcount;
 420         }
 421
 422         list_add(&new_trace->list, &ltt_traces.setup_head);
 423         return 0;
 424
 425 trace_free:
 426         kfree(new_trace);
 427 traces_error:
 428         return err;
 429 }
 430
 431
 432 int ltt_trace_setup(const char *trace_name)
 433 {
 434         int ret;
 435         ltt_lock_traces();
 436         ret = _ltt_trace_setup(trace_name);
 437         ltt_unlock_traces();
 438         return ret;
 439 }
 440
 441 /* must be called from within a traces lock. */
 442 static void _ltt_trace_free(struct ust_trace *trace)
 443 {
 444         list_del(&trace->list);
 445         kfree(trace);
 446 }
 447
 448 int ltt_trace_set_type(const char *trace_name, const char *trace_type)
 449 {
 450         int err = 0;
 451         struct ust_trace *trace;
 452         struct ltt_transport *tran_iter, *transport = NULL;
 453
 454         ltt_lock_traces();
 455
 456         trace = _ltt_trace_find_setup(trace_name);
 457         if (!trace) {
 458                 ERR("Trace not found %s", trace_name);
 459                 err = -ENOENT;
 460                 goto traces_error;
 461         }
 462
 463         list_for_each_entry(tran_iter, &ltt_transport_list, node) {
 464                 if (!strcmp(tran_iter->name, trace_type)) {
 465                         transport = tran_iter;
 466                         break;
 467                 }
 468         }
 469         if (!transport) {
 470                 ERR("Transport %s is not present", trace_type);
 471                 err = -EINVAL;
 472                 goto traces_error;
 473         }
 474
 475         trace->transport = transport;
 476
 477 traces_error:
 478         ltt_unlock_traces();
 479         return err;
 480 }
 481
 482 int ltt_trace_set_channel_subbufsize(const char *trace_name,
 483                 const char *channel_name, unsigned int size)
 484 {
 485         int err = 0;
 486         struct ust_trace *trace;
 487         int index;
 488
 489         ltt_lock_traces();
 490
 491         trace = _ltt_trace_find_setup(trace_name);
 492         if (!trace) {
 493                 ERR("Trace not found %s", trace_name);
 494                 err = -ENOENT;
 495                 goto traces_error;
 496         }
 497
 498         index = ltt_channels_get_index_from_name(channel_name);
 499         if (index < 0) {
 500                 ERR("Channel %s not found", channel_name);
 501                 err = -ENOENT;
 502                 goto traces_error;
 503         }
 504         trace->channels[index].subbuf_size = size;
 505
 506 traces_error:
 507         ltt_unlock_traces();
 508         return err;
 509 }
 510
 511 int ltt_trace_set_channel_subbufcount(const char *trace_name,
 512                 const char *channel_name, unsigned int cnt)
 513 {
 514         int err = 0;
 515         struct ust_trace *trace;
 516         int index;
 517
 518         ltt_lock_traces();
 519
 520         trace = _ltt_trace_find_setup(trace_name);
 521         if (!trace) {
 522                 ERR("Trace not found %s", trace_name);
 523                 err = -ENOENT;
 524                 goto traces_error;
 525         }
 526
 527         index = ltt_channels_get_index_from_name(channel_name);
 528         if (index < 0) {
 529                 ERR("Channel %s not found", channel_name);
 530                 err = -ENOENT;
 531                 goto traces_error;
 532         }
 533         trace->channels[index].subbuf_cnt = cnt;
 534
 535 traces_error:
 536         ltt_unlock_traces();
 537         return err;
 538 }
 539
 540 int ltt_trace_set_channel_enable(const char *trace_name,
 541                 const char *channel_name, unsigned int enable)
 542 {
 543         int err = 0;
 544         struct ust_trace *trace;
 545         int index;
 546
 547         ltt_lock_traces();
 548
 549         trace = _ltt_trace_find_setup(trace_name);
 550         if (!trace) {
 551                 ERR("Trace not found %s", trace_name);
 552                 err = -ENOENT;
 553                 goto traces_error;
 554         }
 555
 556         /*
 557          * Datas in metadata channel(marker info) is necessary to be able to
 558          * read the trace, we always enable this channel.
 559          */
 560         if (!enable && !strcmp(channel_name, "metadata")) {
 561                 ERR("Trying to disable metadata channel");
 562                 err = -EINVAL;
 563                 goto traces_error;
 564         }
 565
 566         index = ltt_channels_get_index_from_name(channel_name);
 567         if (index < 0) {
 568                 ERR("Channel %s not found", channel_name);
 569                 err = -ENOENT;
 570                 goto traces_error;
 571         }
 572
 573         trace->channels[index].active = enable;
 574
 575 traces_error:
 576         ltt_unlock_traces();
 577         return err;
 578 }
 579
 580 int ltt_trace_set_channel_overwrite(const char *trace_name,
 581                 const char *channel_name, unsigned int overwrite)
 582 {
 583         int err = 0;
 584         struct ust_trace *trace;
 585         int index;
 586
 587         ltt_lock_traces();
 588
 589         trace = _ltt_trace_find_setup(trace_name);
 590         if (!trace) {
 591                 ERR("Trace not found %s", trace_name);
 592                 err = -ENOENT;
 593                 goto traces_error;
 594         }
 595
 596         /*
 597          * Always put the metadata channel in non-overwrite mode :
 598          * This is a very low traffic channel and it can't afford to have its
 599          * data overwritten : this data (marker info) is necessary to be
 600          * able to read the trace.
 601          */
 602         if (overwrite && !strcmp(channel_name, "metadata")) {
 603                 ERR("Trying to set metadata channel to overwrite mode");
 604                 err = -EINVAL;
 605                 goto traces_error;
 606         }
 607
 608         index = ltt_channels_get_index_from_name(channel_name);
 609         if (index < 0) {
 610                 ERR("Channel %s not found", channel_name);
 611                 err = -ENOENT;
 612                 goto traces_error;
 613         }
 614
 615         trace->channels[index].overwrite = overwrite;
 616
 617 traces_error:
 618         ltt_unlock_traces();
 619         return err;
 620 }
 621
 622 int ltt_trace_alloc(const char *trace_name)
 623 {
 624         int err = 0;
 625         struct ust_trace *trace;
 626         unsigned int subbuf_size, subbuf_cnt;
 627 //ust// unsigned long flags;
 628         int chan;
 629         const char *channel_name;
 630
 631         ltt_lock_traces();
 632
 633         if (_ltt_trace_find(trace_name)) { /* Trace already allocated */
 634                 err = 1;
 635                 goto traces_error;
 636         }
 637
 638         trace = _ltt_trace_find_setup(trace_name);
 639         if (!trace) {
 640                 ERR("Trace not found %s", trace_name);
 641                 err = -ENOENT;
 642                 goto traces_error;
 643         }
 644
 645         kref_init(&trace->kref);
 646         kref_init(&trace->ltt_transport_kref);
 647 //ust// init_waitqueue_head(&trace->kref_wq);
 648         trace->active = 0;
 649 //ust// get_trace_clock();
 650         trace->freq_scale = trace_clock_freq_scale();
 651
 652         if (!trace->transport) {
 653                 ERR("Transport is not set");
 654                 err = -EINVAL;
 655                 goto transport_error;
 656         }
 657 //ust// if (!try_module_get(trace->transport->owner)) {
 658 //ust//         ERR("Can't lock transport module");
 659 //ust//         err = -ENODEV;
 660 //ust//         goto transport_error;
 661 //ust// }
 662         trace->ops = &trace->transport->ops;
 663
 664 //ust// err = trace->ops->create_dirs(trace);
 665 //ust// if (err) {
 666 //ust//         ERR("Can't create dir for trace %s", trace_name);
 667 //ust//         goto dirs_error;
 668 //ust// }
 669
 670 //ust// local_irq_save(flags);
 671         trace->start_freq = trace_clock_frequency();
 672         trace->start_tsc = trace_clock_read64();
 673         gettimeofday(&trace->start_time, NULL); //ust// changed /* FIXME: is this ok? */
 674 //ust// local_irq_restore(flags);
 675
 676         for (chan = 0; chan < trace->nr_channels; chan++) {
 677                 if (!(trace->channels[chan].active))
 678                         continue;
 679
 680                 channel_name = ltt_channels_get_name_from_index(chan);
 681                 WARN_ON(!channel_name);
 682                 subbuf_size = trace->channels[chan].subbuf_size;
 683                 subbuf_cnt = trace->channels[chan].subbuf_cnt;
 684                 prepare_chan_size_num(&subbuf_size, &subbuf_cnt);
 685                 err = trace->ops->create_channel(trace_name, trace,
 686                                 channel_name,
 687                                 &trace->channels[chan],
 688                                 subbuf_size,
 689                                 subbuf_cnt,
 690                                 trace->channels[chan].overwrite);
 691                 if (err != 0) {
 692                         ERR("Cannot create channel %s", channel_name);
 693                         goto create_channel_error;
 694                 }
 695         }
 696
 697         list_del(&trace->list);
 698 //ust// if (list_empty(&ltt_traces.head)) {
 699 //ust//         mod_timer(&ltt_async_wakeup_timer,
 700 //ust//                         jiffies + LTT_PERCPU_TIMER_INTERVAL);
 701 //ust//         set_kernel_trace_flag_all_tasks();
 702 //ust// }
 703         list_add_rcu(&trace->list, &ltt_traces.head);
 704 //ust// synchronize_sched();
 705
 706         ltt_unlock_traces();
 707
 708         return 0;
 709
 710 create_channel_error:
 711         for (chan--; chan >= 0; chan--)
 712                 if (trace->channels[chan].active)
 713                         trace->ops->remove_channel(&trace->channels[chan]);
 714
 715 //ust// dirs_error:
 716 //ust// module_put(trace->transport->owner);
 717 transport_error:
 718 //ust// put_trace_clock();
 719 traces_error:
 720         ltt_unlock_traces();
 721         return err;
 722 }
 723
 724 /*
 725  * It is worked as a wrapper for current version of ltt_control.ko.
 726  * We will make a new ltt_control based on debugfs, and control each channel's
 727  * buffer.
 728  */
 729 //ust// static int ltt_trace_create(const char *trace_name, const char *trace_type,
 730 //ust//                 enum trace_mode mode,
 731 //ust//                 unsigned int subbuf_size_low, unsigned int n_subbufs_low,
 732 //ust//                 unsigned int subbuf_size_med, unsigned int n_subbufs_med,
 733 //ust//                 unsigned int subbuf_size_high, unsigned int n_subbufs_high)
 734 //ust// {
 735 //ust//         int err = 0;
 736 //ust//
 737 //ust//         err = ltt_trace_setup(trace_name);
 738 //ust//         if (IS_ERR_VALUE(err))
 739 //ust//                 return err;
 740 //ust//
 741 //ust//         err = ltt_trace_set_type(trace_name, trace_type);
 742 //ust//         if (IS_ERR_VALUE(err))
 743 //ust//                 return err;
 744 //ust//
 745 //ust//         err = ltt_trace_alloc(trace_name);
 746 //ust//         if (IS_ERR_VALUE(err))
 747 //ust//                 return err;
 748 //ust//
 749 //ust//         return err;
 750 //ust// }
 751
 752 /* Must be called while sure that trace is in the list. */
 753 static int _ltt_trace_destroy(struct ust_trace *trace)
 754 {
 755         int err = -EPERM;
 756
 757         if (trace == NULL) {
 758                 err = -ENOENT;
 759                 goto traces_error;
 760         }
 761         if (trace->active) {
 762                 ERR("Can't destroy trace %s : tracer is active", trace->trace_name);
 763                 err = -EBUSY;
 764                 goto active_error;
 765         }
 766         /* Everything went fine */
 767         list_del_rcu(&trace->list);
 768         synchronize_rcu();
 769         if (list_empty(&ltt_traces.head)) {
 770 //ust//         clear_kernel_trace_flag_all_tasks();
 771                 /*
 772                  * We stop the asynchronous delivery of reader wakeup, but
 773                  * we must make one last check for reader wakeups pending
 774                  * later in __ltt_trace_destroy.
 775                  */
 776 //ust//         del_timer_sync(&ltt_async_wakeup_timer);
 777         }
 778         return 0;
 779
 780         /* error handling */
 781 active_error:
 782 traces_error:
 783         return err;
 784 }
 785
 786 /* Sleepable part of the destroy */
 787 static void __ltt_trace_destroy(struct ust_trace *trace, int drop)
 788 {
 789         int i;
 790         struct ust_channel *chan;
 791
 792         if(!drop) {
 793                 for (i = 0; i < trace->nr_channels; i++) {
 794                         chan = &trace->channels[i];
 795                         if (chan->active)
 796                                 trace->ops->finish_channel(chan);
 797                 }
 798         }
 799
 800         return; /* FIXME: temporary for ust */
 801 //ust// flush_scheduled_work();
 802
 803         /*
 804          * The currently destroyed trace is not in the trace list anymore,
 805          * so it's safe to call the async wakeup ourself. It will deliver
 806          * the last subbuffers.
 807          */
 808         trace_async_wakeup(trace);
 809
 810         for (i = 0; i < trace->nr_channels; i++) {
 811                 chan = &trace->channels[i];
 812                 if (chan->active)
 813                         trace->ops->remove_channel(chan);
 814         }
 815
 816         kref_put(&trace->ltt_transport_kref, ltt_release_transport);
 817
 818 //ust// module_put(trace->transport->owner);
 819
 820         /*
 821          * Wait for lttd readers to release the files, therefore making sure
 822          * the last subbuffers have been read.
 823          */
 824 //ust// if (atomic_read(&trace->kref.refcount) > 1) {
 825 //ust//         int ret = 0;
 826 //ust//         __wait_event_interruptible(trace->kref_wq,
 827 //ust//                 (atomic_read(&trace->kref.refcount) == 1), ret);
 828 //ust// }
 829         kref_put(&trace->kref, ltt_release_trace);
 830 }
 831
 832 int ltt_trace_destroy(const char *trace_name, int drop)
 833 {
 834         int err = 0;
 835         struct ust_trace *trace;
 836
 837         ltt_lock_traces();
 838
 839         trace = _ltt_trace_find(trace_name);
 840         if (trace) {
 841                 err = _ltt_trace_destroy(trace);
 842                 if (err)
 843                         goto error;
 844
 845                 ltt_unlock_traces();
 846
 847                 __ltt_trace_destroy(trace, drop);
 848 //ust//         put_trace_clock();
 849
 850                 return 0;
 851         }
 852
 853         trace = _ltt_trace_find_setup(trace_name);
 854         if (trace) {
 855                 _ltt_trace_free(trace);
 856                 ltt_unlock_traces();
 857                 return 0;
 858         }
 859
 860         err = -ENOENT;
 861
 862         /* Error handling */
 863 error:
 864         ltt_unlock_traces();
 865         return err;
 866 }
 867
 868 /* must be called from within a traces lock. */
 869 static int _ltt_trace_start(struct ust_trace *trace)
 870 {
 871         int err = 0;
 872
 873         if (trace == NULL) {
 874                 err = -ENOENT;
 875                 goto traces_error;
 876         }
 877         if (trace->active)
 878                 DBG("Tracing already active for trace %s", trace->trace_name);
 879 //ust// if (!try_module_get(ltt_run_filter_owner)) {
 880 //ust//         err = -ENODEV;
 881 //ust//         ERR("Cannot lock filter module");
 882 //ust//         goto get_ltt_run_filter_error;
 883 //ust// }
 884         trace->active = 1;
 885         /* Read by trace points without protection : be careful */
 886         ltt_traces.num_active_traces++;
 887         return err;
 888
 889         /* error handling */
 890 //ust// get_ltt_run_filter_error:
 891 traces_error:
 892         return err;
 893 }
 894
 895 int ltt_trace_start(const char *trace_name)
 896 {
 897         int err = 0;
 898         struct ust_trace *trace;
 899
 900         ltt_lock_traces();
 901
 902         trace = _ltt_trace_find(trace_name);
 903         err = _ltt_trace_start(trace);
 904         if (err)
 905                 goto no_trace;
 906
 907         ltt_unlock_traces();
 908
 909         /*
 910          * Call the kernel state dump.
 911          * Events will be mixed with real kernel events, it's ok.
 912          * Notice that there is no protection on the trace : that's exactly
 913          * why we iterate on the list and check for trace equality instead of
 914          * directly using this trace handle inside the logging function.
 915          */
 916
 917         ltt_dump_marker_state(trace);
 918
 919 //ust// if (!try_module_get(ltt_statedump_owner)) {
 920 //ust//         err = -ENODEV;
 921 //ust//         ERR("Cannot lock state dump module");
 922 //ust// } else {
 923                 ltt_statedump_functor(trace);
 924 //ust//         module_put(ltt_statedump_owner);
 925 //ust// }
 926
 927         return err;
 928
 929         /* Error handling */
 930 no_trace:
 931         ltt_unlock_traces();
 932         return err;
 933 }
 934
 935 /* must be called from within traces lock */
 936 static int _ltt_trace_stop(struct ust_trace *trace)
 937 {
 938         int err = -EPERM;
 939
 940         if (trace == NULL) {
 941                 err = -ENOENT;
 942                 goto traces_error;
 943         }
 944         if (!trace->active)
 945                 DBG("LTT : Tracing not active for trace %s", trace->trace_name);
 946         if (trace->active) {
 947                 trace->active = 0;
 948                 ltt_traces.num_active_traces--;
 949 //ust//         synchronize_sched(); /* Wait for each tracing to be finished */
 950         }
 951 //ust// module_put(ltt_run_filter_owner);
 952         /* Everything went fine */
 953         return 0;
 954
 955         /* Error handling */
 956 traces_error:
 957         return err;
 958 }
 959
 960 int ltt_trace_stop(const char *trace_name)
 961 {
 962         int err = 0;
 963         struct ust_trace *trace;
 964
 965         ltt_lock_traces();
 966         trace = _ltt_trace_find(trace_name);
 967         err = _ltt_trace_stop(trace);
 968         ltt_unlock_traces();
 969         return err;
 970 }
 971
 972 /**
 973  * ltt_filter_control - Trace filter control in-kernel API
 974  * @msg: Action to perform on the filter
 975  * @trace_name: Trace on which the action must be done
 976  */
 977 int ltt_filter_control(enum ltt_filter_control_msg msg, const char *trace_name)
 978 {
 979         int err;
 980         struct ust_trace *trace;
 981
 982         DBG("ltt_filter_control : trace %s", trace_name);
 983         ltt_lock_traces();
 984         trace = _ltt_trace_find(trace_name);
 985         if (trace == NULL) {
 986                 ERR("Trace does not exist. Cannot proxy control request");
 987                 err = -ENOENT;
 988                 goto trace_error;
 989         }
 990 //ust// if (!try_module_get(ltt_filter_control_owner)) {
 991 //ust//         err = -ENODEV;
 992 //ust//         goto get_module_error;
 993 //ust// }
 994         switch (msg) {
 995         case LTT_FILTER_DEFAULT_ACCEPT:
 996                 DBG("Proxy filter default accept %s", trace_name);
 997                 err = (*ltt_filter_control_functor)(msg, trace);
 998                 break;
 999         case LTT_FILTER_DEFAULT_REJECT:
1000                 DBG("Proxy filter default reject %s", trace_name);
1001                 err = (*ltt_filter_control_functor)(msg, trace);
1002                 break;
1003         default:
1004                 err = -EPERM;
1005         }
1006 //ust// module_put(ltt_filter_control_owner);
1007
1008 //ust// get_module_error:
1009 trace_error:
1010         ltt_unlock_traces();
1011         return err;
1012 }