ltt-debugfs-abi.c

   1 /*
   2  * ltt-debugfs-abi.c
   3  *
   4  * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng debugfs ABI
   7  *
   8  * Mimic system calls for:
   9  * - session creation, returns a file descriptor or failure.
  10  *   - channel creation, returns a file descriptor or failure.
  11  *     - Operates on a session file descriptor
  12  *     - Takes all channel options as parameters.
  13  *   - stream get, returns a file descriptor or failure.
  14  *     - Operates on a channel file descriptor.
  15  *   - stream notifier get, returns a file descriptor or failure.
  16  *     - Operates on a channel file descriptor.
  17  *   - event creation, returns a file descriptor or failure.
  18  *     - Operates on a channel file descriptor
  19  *     - Takes an event name as parameter
  20  *     - Takes an instrumentation source as parameter
  21  *       - e.g. tracepoints, dynamic_probes...
  22  *     - Takes instrumentation source specific arguments.
  23  *
  24  * Dual LGPL v2.1/GPL v2 license.
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/debugfs.h>
  29 #include <linux/anon_inodes.h>
  30 #include <linux/file.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/slab.h>
  33 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  34 #include "wrapper/ringbuffer/vfs.h"
  35 #include "wrapper/poll.h"
  36 #include "ltt-debugfs-abi.h"
  37 #include "ltt-events.h"
  38 #include "ltt-tracer.h"
  39
  40 /*
  41  * This is LTTng's own personal way to create a system call as an external
  42  * module. We use ioctl() on /sys/kernel/debug/lttng.
  43  */
  44
  45 static struct dentry *lttng_dentry;
  46 static const struct file_operations lttng_fops;
  47 static const struct file_operations lttng_session_fops;
  48 static const struct file_operations lttng_channel_fops;
  49 static const struct file_operations lttng_metadata_fops;
  50 static const struct file_operations lttng_event_fops;
  51
  52 enum channel_type {
  53         PER_CPU_CHANNEL,
  54         METADATA_CHANNEL,
  55 };
  56
  57 static
  58 int lttng_abi_create_session(void)
  59 {
  60         struct ltt_session *session;
  61         struct file *session_file;
  62         int session_fd, ret;
  63
  64         session = ltt_session_create();
  65         if (!session)
  66                 return -ENOMEM;
  67         session_fd = get_unused_fd();
  68         if (session_fd < 0) {
  69                 ret = session_fd;
  70                 goto fd_error;
  71         }
  72         session_file = anon_inode_getfile("[lttng_session]",
  73                                           &lttng_session_fops,
  74                                           session, O_RDWR);
  75         if (IS_ERR(session_file)) {
  76                 ret = PTR_ERR(session_file);
  77                 goto file_error;
  78         }
  79         session->file = session_file;
  80         fd_install(session_fd, session_file);
  81         return session_fd;
  82
  83 file_error:
  84         put_unused_fd(session_fd);
  85 fd_error:
  86         ltt_session_destroy(session);
  87         return ret;
  88 }
  89
  90 static
  91 int lttng_abi_tracepoint_list(void)
  92 {
  93         struct file *tracepoint_list_file;
  94         int file_fd, ret;
  95
  96         file_fd = get_unused_fd();
  97         if (file_fd < 0) {
  98                 ret = file_fd;
  99                 goto fd_error;
 100         }
 101
 102         tracepoint_list_file = anon_inode_getfile("[lttng_session]",
 103                                           &lttng_tracepoint_list_fops,
 104                                           NULL, O_RDWR);
 105         if (IS_ERR(tracepoint_list_file)) {
 106                 ret = PTR_ERR(tracepoint_list_file);
 107                 goto file_error;
 108         }
 109         ret = lttng_tracepoint_list_fops.open(NULL, tracepoint_list_file);
 110         if (ret < 0)
 111                 goto open_error;
 112         fd_install(file_fd, tracepoint_list_file);
 113         if (file_fd < 0) {
 114                 ret = file_fd;
 115                 goto fd_error;
 116         }
 117         return file_fd;
 118
 119 open_error:
 120         fput(tracepoint_list_file);
 121 file_error:
 122         put_unused_fd(file_fd);
 123 fd_error:
 124         return ret;
 125 }
 126
 127 static
 128 long lttng_abi_tracer_version(struct file *file,
 129         struct lttng_kernel_tracer_version __user *uversion_param)
 130 {
 131         struct lttng_kernel_tracer_version v;
 132
 133         v.version = LTTNG_VERSION;
 134         v.patchlevel = LTTNG_PATCHLEVEL;
 135         v.sublevel = LTTNG_SUBLEVEL;
 136
 137         if (copy_to_user(uversion_param, &v, sizeof(v)))
 138                 return -EFAULT;
 139         return 0;
 140 }
 141
 142 static
 143 long lttng_abi_add_context(struct file *file,
 144         struct lttng_kernel_context __user *ucontext_param,
 145         struct lttng_ctx **ctx, struct ltt_session *session)
 146 {
 147         struct lttng_kernel_context context_param;
 148
 149         if (session->been_active)
 150                 return -EPERM;
 151
 152         if (copy_from_user(&context_param, ucontext_param, sizeof(context_param)))
 153                 return -EFAULT;
 154
 155         switch (context_param.ctx) {
 156         case LTTNG_KERNEL_CONTEXT_PID:
 157                 return lttng_add_pid_to_ctx(ctx);
 158         case LTTNG_KERNEL_CONTEXT_PRIO:
 159                 return lttng_add_prio_to_ctx(ctx);
 160         case LTTNG_KERNEL_CONTEXT_NICE:
 161                 return lttng_add_nice_to_ctx(ctx);
 162         case LTTNG_KERNEL_CONTEXT_VPID:
 163                 return lttng_add_vpid_to_ctx(ctx);
 164         case LTTNG_KERNEL_CONTEXT_TID:
 165                 return lttng_add_tid_to_ctx(ctx);
 166         case LTTNG_KERNEL_CONTEXT_VTID:
 167                 return lttng_add_vtid_to_ctx(ctx);
 168         case LTTNG_KERNEL_CONTEXT_PPID:
 169                 return lttng_add_ppid_to_ctx(ctx);
 170         case LTTNG_KERNEL_CONTEXT_VPPID:
 171                 return lttng_add_vppid_to_ctx(ctx);
 172         case LTTNG_KERNEL_CONTEXT_PERF_COUNTER:
 173                 context_param.u.perf_counter.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
 174                 return lttng_add_perf_counter_to_ctx(context_param.u.perf_counter.type,
 175                                 context_param.u.perf_counter.config,
 176                                 context_param.u.perf_counter.name,
 177                                 ctx);
 178         case LTTNG_KERNEL_CONTEXT_COMM:
 179                 return lttng_add_comm_to_ctx(ctx);
 180         default:
 181                 return -EINVAL;
 182         }
 183 }
 184
 185 /**
 186  *      lttng_ioctl - lttng syscall through ioctl
 187  *
 188  *      @file: the file
 189  *      @cmd: the command
 190  *      @arg: command arg
 191  *
 192  *      This ioctl implements lttng commands:
 193  *      LTTNG_KERNEL_SESSION
 194  *              Returns a LTTng trace session file descriptor
 195  *      LTTNG_KERNEL_TRACER_VERSION
 196  *              Returns the LTTng kernel tracer version
 197  *      LTTNG_KERNEL_TRACEPOINT_LIST
 198  *              Returns a file descriptor listing available tracepoints
 199  *      LTTNG_KERNEL_WAIT_QUIESCENT
 200  *              Returns after all previously running probes have completed
 201  *
 202  * The returned session will be deleted when its file descriptor is closed.
 203  */
 204 static
 205 long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 206 {
 207         switch (cmd) {
 208         case LTTNG_KERNEL_SESSION:
 209                 return lttng_abi_create_session();
 210         case LTTNG_KERNEL_TRACER_VERSION:
 211                 return lttng_abi_tracer_version(file,
 212                                 (struct lttng_kernel_tracer_version __user *) arg);
 213         case LTTNG_KERNEL_TRACEPOINT_LIST:
 214                 return lttng_abi_tracepoint_list();
 215         default:
 216                 return -ENOIOCTLCMD;
 217         }
 218 }
 219
 220 static const struct file_operations lttng_fops = {
 221         .unlocked_ioctl = lttng_ioctl,
 222 #ifdef CONFIG_COMPAT
 223         .compat_ioctl = lttng_ioctl,
 224 #endif
 225 };
 226
 227 /*
 228  * We tolerate no failure in this function (if one happens, we print a dmesg
 229  * error, but cannot return any error, because the channel information is
 230  * invariant.
 231  */
 232 static
 233 void lttng_metadata_create_events(struct file *channel_file)
 234 {
 235         struct ltt_channel *channel = channel_file->private_data;
 236         static struct lttng_kernel_event metadata_params = {
 237                 .instrumentation = LTTNG_KERNEL_TRACEPOINT,
 238                 .name = "lttng_metadata",
 239         };
 240         struct ltt_event *event;
 241         int ret;
 242
 243         /*
 244          * We tolerate no failure path after event creation. It will stay
 245          * invariant for the rest of the session.
 246          */
 247         event = ltt_event_create(channel, &metadata_params, NULL);
 248         if (!event) {
 249                 ret = -EINVAL;
 250                 goto create_error;
 251         }
 252         return;
 253
 254 create_error:
 255         WARN_ON(1);
 256         return;         /* not allowed to return error */
 257 }
 258
 259 static
 260 int lttng_abi_create_channel(struct file *session_file,
 261                              struct lttng_kernel_channel __user *uchan_param,
 262                              enum channel_type channel_type)
 263 {
 264         struct ltt_session *session = session_file->private_data;
 265         const struct file_operations *fops;
 266         const char *transport_name;
 267         struct ltt_channel *chan;
 268         struct file *chan_file;
 269         struct lttng_kernel_channel chan_param;
 270         int chan_fd;
 271         int ret = 0;
 272
 273         if (copy_from_user(&chan_param, uchan_param, sizeof(chan_param)))
 274                 return -EFAULT;
 275         chan_fd = get_unused_fd();
 276         if (chan_fd < 0) {
 277                 ret = chan_fd;
 278                 goto fd_error;
 279         }
 280         chan_file = anon_inode_getfile("[lttng_channel]",
 281                                        &lttng_channel_fops,
 282                                        NULL, O_RDWR);
 283         if (IS_ERR(chan_file)) {
 284                 ret = PTR_ERR(chan_file);
 285                 goto file_error;
 286         }
 287         switch (channel_type) {
 288         case PER_CPU_CHANNEL:
 289                 transport_name = chan_param.overwrite ?
 290                         "relay-overwrite" : "relay-discard";
 291                 fops = &lttng_channel_fops;
 292                 break;
 293         case METADATA_CHANNEL:
 294                 transport_name = "relay-metadata";
 295                 fops = &lttng_metadata_fops;
 296                 break;
 297         default:
 298                 transport_name = "<unknown>";
 299                 break;
 300         }
 301         /*
 302          * We tolerate no failure path after channel creation. It will stay
 303          * invariant for the rest of the session.
 304          */
 305         chan = ltt_channel_create(session, transport_name, NULL,
 306                                   chan_param.subbuf_size,
 307                                   chan_param.num_subbuf,
 308                                   chan_param.switch_timer_interval,
 309                                   chan_param.read_timer_interval);
 310         if (!chan) {
 311                 ret = -EINVAL;
 312                 goto chan_error;
 313         }
 314         chan->file = chan_file;
 315         chan_file->private_data = chan;
 316         fd_install(chan_fd, chan_file);
 317         if (channel_type == METADATA_CHANNEL) {
 318                 session->metadata = chan;
 319                 lttng_metadata_create_events(chan_file);
 320         }
 321
 322         /* The channel created holds a reference on the session */
 323         atomic_long_inc(&session_file->f_count);
 324
 325         return chan_fd;
 326
 327 chan_error:
 328         fput(chan_file);
 329 file_error:
 330         put_unused_fd(chan_fd);
 331 fd_error:
 332         return ret;
 333 }
 334
 335 /**
 336  *      lttng_session_ioctl - lttng session fd ioctl
 337  *
 338  *      @file: the file
 339  *      @cmd: the command
 340  *      @arg: command arg
 341  *
 342  *      This ioctl implements lttng commands:
 343  *      LTTNG_KERNEL_CHANNEL
 344  *              Returns a LTTng channel file descriptor
 345  *      LTTNG_KERNEL_ENABLE
 346  *              Enables tracing for a session (weak enable)
 347  *      LTTNG_KERNEL_DISABLE
 348  *              Disables tracing for a session (strong disable)
 349  *      LTTNG_KERNEL_METADATA
 350  *              Returns a LTTng metadata file descriptor
 351  *
 352  * The returned channel will be deleted when its file descriptor is closed.
 353  */
 354 static
 355 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 356 {
 357         struct ltt_session *session = file->private_data;
 358
 359         switch (cmd) {
 360         case LTTNG_KERNEL_CHANNEL:
 361                 return lttng_abi_create_channel(file,
 362                                 (struct lttng_kernel_channel __user *) arg,
 363                                 PER_CPU_CHANNEL);
 364         case LTTNG_KERNEL_SESSION_START:
 365         case LTTNG_KERNEL_ENABLE:
 366                 return ltt_session_enable(session);
 367         case LTTNG_KERNEL_SESSION_STOP:
 368         case LTTNG_KERNEL_DISABLE:
 369                 return ltt_session_disable(session);
 370         case LTTNG_KERNEL_METADATA:
 371                 return lttng_abi_create_channel(file,
 372                                 (struct lttng_kernel_channel __user *) arg,
 373                                 METADATA_CHANNEL);
 374         default:
 375                 return -ENOIOCTLCMD;
 376         }
 377 }
 378
 379 /*
 380  * Called when the last file reference is dropped.
 381  *
 382  * Big fat note: channels and events are invariant for the whole session after
 383  * their creation. So this session destruction also destroys all channel and
 384  * event structures specific to this session (they are not destroyed when their
 385  * individual file is released).
 386  */
 387 static
 388 int lttng_session_release(struct inode *inode, struct file *file)
 389 {
 390         struct ltt_session *session = file->private_data;
 391
 392         if (session)
 393                 ltt_session_destroy(session);
 394         return 0;
 395 }
 396
 397 static const struct file_operations lttng_session_fops = {
 398         .release = lttng_session_release,
 399         .unlocked_ioctl = lttng_session_ioctl,
 400 #ifdef CONFIG_COMPAT
 401         .compat_ioctl = lttng_session_ioctl,
 402 #endif
 403 };
 404
 405 static
 406 int lttng_abi_open_stream(struct file *channel_file)
 407 {
 408         struct ltt_channel *channel = channel_file->private_data;
 409         struct lib_ring_buffer *buf;
 410         int stream_fd, ret;
 411         struct file *stream_file;
 412
 413         buf = channel->ops->buffer_read_open(channel->chan);
 414         if (!buf)
 415                 return -ENOENT;
 416
 417         stream_fd = get_unused_fd();
 418         if (stream_fd < 0) {
 419                 ret = stream_fd;
 420                 goto fd_error;
 421         }
 422         stream_file = anon_inode_getfile("[lttng_stream]",
 423                                          &lib_ring_buffer_file_operations,
 424                                          buf, O_RDWR);
 425         if (IS_ERR(stream_file)) {
 426                 ret = PTR_ERR(stream_file);
 427                 goto file_error;
 428         }
 429         /*
 430          * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
 431          * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
 432          * file descriptor, so we set FMODE_PREAD here.
 433          */
 434         stream_file->f_mode |= FMODE_PREAD;
 435         fd_install(stream_fd, stream_file);
 436         /*
 437          * The stream holds a reference to the channel within the generic ring
 438          * buffer library, so no need to hold a refcount on the channel and
 439          * session files here.
 440          */
 441         return stream_fd;
 442
 443 file_error:
 444         put_unused_fd(stream_fd);
 445 fd_error:
 446         channel->ops->buffer_read_close(buf);
 447         return ret;
 448 }
 449
 450 static
 451 int lttng_abi_create_event(struct file *channel_file,
 452                            struct lttng_kernel_event __user *uevent_param)
 453 {
 454         struct ltt_channel *channel = channel_file->private_data;
 455         struct ltt_event *event;
 456         struct lttng_kernel_event event_param;
 457         int event_fd, ret;
 458         struct file *event_file;
 459
 460         if (copy_from_user(&event_param, uevent_param, sizeof(event_param)))
 461                 return -EFAULT;
 462         event_param.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
 463         switch (event_param.instrumentation) {
 464         case LTTNG_KERNEL_KPROBE:
 465                 event_param.u.kprobe.symbol_name[LTTNG_SYM_NAME_LEN - 1] = '\0';
 466                 break;
 467         case LTTNG_KERNEL_FUNCTION:
 468                 event_param.u.ftrace.symbol_name[LTTNG_SYM_NAME_LEN - 1] = '\0';
 469                 break;
 470         default:
 471                 break;
 472         }
 473         event_fd = get_unused_fd();
 474         if (event_fd < 0) {
 475                 ret = event_fd;
 476                 goto fd_error;
 477         }
 478         event_file = anon_inode_getfile("[lttng_event]",
 479                                         &lttng_event_fops,
 480                                         NULL, O_RDWR);
 481         if (IS_ERR(event_file)) {
 482                 ret = PTR_ERR(event_file);
 483                 goto file_error;
 484         }
 485         /*
 486          * We tolerate no failure path after event creation. It will stay
 487          * invariant for the rest of the session.
 488          */
 489         event = ltt_event_create(channel, &event_param, NULL);
 490         if (!event) {
 491                 ret = -EINVAL;
 492                 goto event_error;
 493         }
 494         event_file->private_data = event;
 495         fd_install(event_fd, event_file);
 496         /* The event holds a reference on the channel */
 497         atomic_long_inc(&channel_file->f_count);
 498         return event_fd;
 499
 500 event_error:
 501         fput(event_file);
 502 file_error:
 503         put_unused_fd(event_fd);
 504 fd_error:
 505         return ret;
 506 }
 507
 508 /**
 509  *      lttng_channel_ioctl - lttng syscall through ioctl
 510  *
 511  *      @file: the file
 512  *      @cmd: the command
 513  *      @arg: command arg
 514  *
 515  *      This ioctl implements lttng commands:
 516  *      LTTNG_KERNEL_STREAM
 517  *              Returns an event stream file descriptor or failure.
 518  *              (typically, one event stream records events from one CPU)
 519  *      LTTNG_KERNEL_EVENT
 520  *              Returns an event file descriptor or failure.
 521  *      LTTNG_KERNEL_CONTEXT
 522  *              Prepend a context field to each event in the channel
 523  *      LTTNG_KERNEL_ENABLE
 524  *              Enable recording for events in this channel (weak enable)
 525  *      LTTNG_KERNEL_DISABLE
 526  *              Disable recording for events in this channel (strong disable)
 527  *
 528  * Channel and event file descriptors also hold a reference on the session.
 529  */
 530 static
 531 long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 532 {
 533         struct ltt_channel *channel = file->private_data;
 534
 535         switch (cmd) {
 536         case LTTNG_KERNEL_STREAM:
 537                 return lttng_abi_open_stream(file);
 538         case LTTNG_KERNEL_EVENT:
 539                 return lttng_abi_create_event(file, (struct lttng_kernel_event __user *) arg);
 540         case LTTNG_KERNEL_CONTEXT:
 541                 return lttng_abi_add_context(file,
 542                                 (struct lttng_kernel_context __user *) arg,
 543                                 &channel->ctx, channel->session);
 544         case LTTNG_KERNEL_ENABLE:
 545                 return ltt_channel_enable(channel);
 546         case LTTNG_KERNEL_DISABLE:
 547                 return ltt_channel_disable(channel);
 548         default:
 549                 return -ENOIOCTLCMD;
 550         }
 551 }
 552
 553 /**
 554  *      lttng_metadata_ioctl - lttng syscall through ioctl
 555  *
 556  *      @file: the file
 557  *      @cmd: the command
 558  *      @arg: command arg
 559  *
 560  *      This ioctl implements lttng commands:
 561  *      LTTNG_KERNEL_STREAM
 562  *              Returns an event stream file descriptor or failure.
 563  *
 564  * Channel and event file descriptors also hold a reference on the session.
 565  */
 566 static
 567 long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 568 {
 569         switch (cmd) {
 570         case LTTNG_KERNEL_STREAM:
 571                 return lttng_abi_open_stream(file);
 572         default:
 573                 return -ENOIOCTLCMD;
 574         }
 575 }
 576
 577 /**
 578  *      lttng_channel_poll - lttng stream addition/removal monitoring
 579  *
 580  *      @file: the file
 581  *      @wait: poll table
 582  */
 583 unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
 584 {
 585         struct ltt_channel *channel = file->private_data;
 586         unsigned int mask = 0;
 587
 588         if (file->f_mode & FMODE_READ) {
 589                 poll_wait_set_exclusive(wait);
 590                 poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
 591                           wait);
 592
 593                 if (channel->ops->is_disabled(channel->chan))
 594                         return POLLERR;
 595                 if (channel->ops->is_finalized(channel->chan))
 596                         return POLLHUP;
 597                 else
 598                         return POLLIN | POLLRDNORM;
 599         }
 600         return mask;
 601
 602 }
 603
 604 static
 605 int lttng_channel_release(struct inode *inode, struct file *file)
 606 {
 607         struct ltt_channel *channel = file->private_data;
 608
 609         if (channel)
 610                 fput(channel->session->file);
 611         return 0;
 612 }
 613
 614 static const struct file_operations lttng_channel_fops = {
 615         .release = lttng_channel_release,
 616         .poll = lttng_channel_poll,
 617         .unlocked_ioctl = lttng_channel_ioctl,
 618 #ifdef CONFIG_COMPAT
 619         .compat_ioctl = lttng_channel_ioctl,
 620 #endif
 621 };
 622
 623 static const struct file_operations lttng_metadata_fops = {
 624         .release = lttng_channel_release,
 625         .unlocked_ioctl = lttng_metadata_ioctl,
 626 #ifdef CONFIG_COMPAT
 627         .compat_ioctl = lttng_metadata_ioctl,
 628 #endif
 629 };
 630
 631 /**
 632  *      lttng_event_ioctl - lttng syscall through ioctl
 633  *
 634  *      @file: the file
 635  *      @cmd: the command
 636  *      @arg: command arg
 637  *
 638  *      This ioctl implements lttng commands:
 639  *      LTTNG_KERNEL_CONTEXT
 640  *              Prepend a context field to each record of this event
 641  *      LTTNG_KERNEL_ENABLE
 642  *              Enable recording for this event (weak enable)
 643  *      LTTNG_KERNEL_DISABLE
 644  *              Disable recording for this event (strong disable)
 645  */
 646 static
 647 long lttng_event_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 648 {
 649         struct ltt_event *event = file->private_data;
 650
 651         switch (cmd) {
 652         case LTTNG_KERNEL_CONTEXT:
 653                 return lttng_abi_add_context(file,
 654                                 (struct lttng_kernel_context __user *) arg,
 655                                 &event->ctx, event->chan->session);
 656         case LTTNG_KERNEL_ENABLE:
 657                 return ltt_event_enable(event);
 658         case LTTNG_KERNEL_DISABLE:
 659                 return ltt_event_disable(event);
 660         default:
 661                 return -ENOIOCTLCMD;
 662         }
 663 }
 664
 665 static
 666 int lttng_event_release(struct inode *inode, struct file *file)
 667 {
 668         struct ltt_event *event = file->private_data;
 669
 670         if (event)
 671                 fput(event->chan->file);
 672         return 0;
 673 }
 674
 675 /* TODO: filter control ioctl */
 676 static const struct file_operations lttng_event_fops = {
 677         .release = lttng_event_release,
 678         .unlocked_ioctl = lttng_event_ioctl,
 679 #ifdef CONFIG_COMPAT
 680         .compat_ioctl = lttng_event_ioctl,
 681 #endif
 682 };
 683
 684 int __init ltt_debugfs_abi_init(void)
 685 {
 686         int ret = 0;
 687
 688         wrapper_vmalloc_sync_all();
 689         lttng_dentry = debugfs_create_file("lttng", S_IWUSR, NULL, NULL,
 690                                            &lttng_fops);
 691         if (IS_ERR(lttng_dentry) || !lttng_dentry) {
 692                 printk(KERN_ERR "Error creating LTTng control file\n");
 693                 ret = -ENOMEM;
 694                 goto error;
 695         }
 696 error:
 697         return ret;
 698 }
 699
 700 void __exit ltt_debugfs_abi_exit(void)
 701 {
 702         debugfs_remove(lttng_dentry);
 703 }