kernel/trace/blktrace.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
   4  *
   5  */
   6
   7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   8
   9 #include <linux/kernel.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/blktrace_api.h>
  12 #include <linux/percpu.h>
  13 #include <linux/init.h>
  14 #include <linux/mutex.h>
  15 #include <linux/slab.h>
  16 #include <linux/debugfs.h>
  17 #include <linux/export.h>
  18 #include <linux/time.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/list.h>
  21 #include <linux/blk-cgroup.h>
  22
  23 #include "../../block/blk.h"
  24
  25 #include <trace/events/block.h>
  26
  27 #include "trace_output.h"
  28
  29 #ifdef CONFIG_BLK_DEV_IO_TRACE
  30
  31 static unsigned int blktrace_seq __read_mostly = 1;
  32
  33 static struct trace_array *blk_tr;
  34 static bool blk_tracer_enabled __read_mostly;
  35
  36 static LIST_HEAD(running_trace_list);
  37 static __cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(running_trace_lock);
  38
  39 /* Select an alternative, minimalistic output than the original one */
  40 #define TRACE_BLK_OPT_CLASSIC   0x1
  41 #define TRACE_BLK_OPT_CGROUP    0x2
  42 #define TRACE_BLK_OPT_CGNAME    0x4
  43
  44 static struct tracer_opt blk_tracer_opts[] = {
  45         /* Default disable the minimalistic output */
  46         { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
  47 #ifdef CONFIG_BLK_CGROUP
  48         { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
  49         { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
  50 #endif
  51         { }
  52 };
  53
  54 static struct tracer_flags blk_tracer_flags = {
  55         .val  = 0,
  56         .opts = blk_tracer_opts,
  57 };
  58
  59 /* Global reference count of probes */
  60 static DEFINE_MUTEX(blk_probe_mutex);
  61 static int blk_probes_ref;
  62
  63 static void blk_register_tracepoints(void);
  64 static void blk_unregister_tracepoints(void);
  65
  66 /*
  67  * Send out a notify message.
  68  */
  69 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
  70                        const void *data, size_t len, u64 cgid)
  71 {
  72         struct blk_io_trace *t;
  73         struct ring_buffer_event *event = NULL;
  74         struct trace_buffer *buffer = NULL;
  75         unsigned int trace_ctx = 0;
  76         int cpu = smp_processor_id();
  77         bool blk_tracer = blk_tracer_enabled;
  78         ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
  79
  80         if (blk_tracer) {
  81                 buffer = blk_tr->array_buffer.buffer;
  82                 trace_ctx = tracing_gen_ctx_flags(0);
  83                 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
  84                                                   sizeof(*t) + len + cgid_len,
  85                                                   trace_ctx);
  86                 if (!event)
  87                         return;
  88                 t = ring_buffer_event_data(event);
  89                 goto record_it;
  90         }
  91
  92         if (!bt->rchan)
  93                 return;
  94
  95         t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len);
  96         if (t) {
  97                 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
  98                 t->time = ktime_to_ns(ktime_get());
  99 record_it:
 100                 t->device = bt->dev;
 101                 t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
 102                 t->pid = pid;
 103                 t->cpu = cpu;
 104                 t->pdu_len = len + cgid_len;
 105                 if (cgid_len)
 106                         memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
 107                 memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
 108
 109                 if (blk_tracer)
 110                         trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
 111         }
 112 }
 113
 114 /*
 115  * Send out a notify for this process, if we haven't done so since a trace
 116  * started
 117  */
 118 static void trace_note_tsk(struct task_struct *tsk)
 119 {
 120         unsigned long flags;
 121         struct blk_trace *bt;
 122
 123         tsk->btrace_seq = blktrace_seq;
 124         raw_spin_lock_irqsave(&running_trace_lock, flags);
 125         list_for_each_entry(bt, &running_trace_list, running_list) {
 126                 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
 127                            sizeof(tsk->comm), 0);
 128         }
 129         raw_spin_unlock_irqrestore(&running_trace_lock, flags);
 130 }
 131
 132 static void trace_note_time(struct blk_trace *bt)
 133 {
 134         struct timespec64 now;
 135         unsigned long flags;
 136         u32 words[2];
 137
 138         /* need to check user space to see if this breaks in y2038 or y2106 */
 139         ktime_get_real_ts64(&now);
 140         words[0] = (u32)now.tv_sec;
 141         words[1] = now.tv_nsec;
 142
 143         local_irq_save(flags);
 144         trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), 0);
 145         local_irq_restore(flags);
 146 }
 147
 148 void __blk_trace_note_message(struct blk_trace *bt,
 149                 struct cgroup_subsys_state *css, const char *fmt, ...)
 150 {
 151         int n;
 152         va_list args;
 153         unsigned long flags;
 154         char *buf;
 155         u64 cgid = 0;
 156
 157         if (unlikely(bt->trace_state != Blktrace_running &&
 158                      !blk_tracer_enabled))
 159                 return;
 160
 161         /*
 162          * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
 163          * message to the trace.
 164          */
 165         if (!(bt->act_mask & BLK_TC_NOTIFY))
 166                 return;
 167
 168         local_irq_save(flags);
 169         buf = this_cpu_ptr(bt->msg_data);
 170         va_start(args, fmt);
 171         n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
 172         va_end(args);
 173
 174 #ifdef CONFIG_BLK_CGROUP
 175         if (css && (blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
 176                 cgid = cgroup_id(css->cgroup);
 177         else
 178                 cgid = 1;
 179 #endif
 180         trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n, cgid);
 181         local_irq_restore(flags);
 182 }
 183 EXPORT_SYMBOL_GPL(__blk_trace_note_message);
 184
 185 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
 186                          pid_t pid)
 187 {
 188         if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
 189                 return 1;
 190         if (sector && (sector < bt->start_lba || sector > bt->end_lba))
 191                 return 1;
 192         if (bt->pid && pid != bt->pid)
 193                 return 1;
 194
 195         return 0;
 196 }
 197
 198 /*
 199  * Data direction bit lookup
 200  */
 201 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
 202                                  BLK_TC_ACT(BLK_TC_WRITE) };
 203
 204 #define BLK_TC_RAHEAD           BLK_TC_AHEAD
 205 #define BLK_TC_PREFLUSH         BLK_TC_FLUSH
 206
 207 /* The ilog2() calls fall out because they're constant */
 208 #define MASK_TC_BIT(rw, __name) ((__force u32)(rw & REQ_ ## __name) <<  \
 209           (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
 210
 211 /*
 212  * The worker for the various blk_add_trace*() types. Fills out a
 213  * blk_io_trace structure and places it in a per-cpu subbuffer.
 214  */
 215 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
 216                             const blk_opf_t opf, u32 what, int error,
 217                             int pdu_len, void *pdu_data, u64 cgid)
 218 {
 219         struct task_struct *tsk = current;
 220         struct ring_buffer_event *event = NULL;
 221         struct trace_buffer *buffer = NULL;
 222         struct blk_io_trace *t;
 223         unsigned long flags = 0;
 224         unsigned long *sequence;
 225         unsigned int trace_ctx = 0;
 226         pid_t pid;
 227         int cpu;
 228         bool blk_tracer = blk_tracer_enabled;
 229         ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
 230         const enum req_op op = opf & REQ_OP_MASK;
 231
 232         if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
 233                 return;
 234
 235         what |= ddir_act[op_is_write(op) ? WRITE : READ];
 236         what |= MASK_TC_BIT(opf, SYNC);
 237         what |= MASK_TC_BIT(opf, RAHEAD);
 238         what |= MASK_TC_BIT(opf, META);
 239         what |= MASK_TC_BIT(opf, PREFLUSH);
 240         what |= MASK_TC_BIT(opf, FUA);
 241         if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
 242                 what |= BLK_TC_ACT(BLK_TC_DISCARD);
 243         if (op == REQ_OP_FLUSH)
 244                 what |= BLK_TC_ACT(BLK_TC_FLUSH);
 245         if (cgid)
 246                 what |= __BLK_TA_CGROUP;
 247
 248         pid = tsk->pid;
 249         if (act_log_check(bt, what, sector, pid))
 250                 return;
 251         cpu = raw_smp_processor_id();
 252
 253         if (blk_tracer) {
 254                 tracing_record_cmdline(current);
 255
 256                 buffer = blk_tr->array_buffer.buffer;
 257                 trace_ctx = tracing_gen_ctx_flags(0);
 258                 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
 259                                                   sizeof(*t) + pdu_len + cgid_len,
 260                                                   trace_ctx);
 261                 if (!event)
 262                         return;
 263                 t = ring_buffer_event_data(event);
 264                 goto record_it;
 265         }
 266
 267         if (unlikely(tsk->btrace_seq != blktrace_seq))
 268                 trace_note_tsk(tsk);
 269
 270         /*
 271          * A word about the locking here - we disable interrupts to reserve
 272          * some space in the relay per-cpu buffer, to prevent an irq
 273          * from coming in and stepping on our toes.
 274          */
 275         local_irq_save(flags);
 276         t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
 277         if (t) {
 278                 sequence = per_cpu_ptr(bt->sequence, cpu);
 279
 280                 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
 281                 t->sequence = ++(*sequence);
 282                 t->time = ktime_to_ns(ktime_get());
 283 record_it:
 284                 /*
 285                  * These two are not needed in ftrace as they are in the
 286                  * generic trace_entry, filled by tracing_generic_entry_update,
 287                  * but for the trace_event->bin() synthesizer benefit we do it
 288                  * here too.
 289                  */
 290                 t->cpu = cpu;
 291                 t->pid = pid;
 292
 293                 t->sector = sector;
 294                 t->bytes = bytes;
 295                 t->action = what;
 296                 t->device = bt->dev;
 297                 t->error = error;
 298                 t->pdu_len = pdu_len + cgid_len;
 299
 300                 if (cgid_len)
 301                         memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
 302                 if (pdu_len)
 303                         memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
 304
 305                 if (blk_tracer) {
 306                         trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
 307                         return;
 308                 }
 309         }
 310
 311         local_irq_restore(flags);
 312 }
 313
 314 static void blk_trace_free(struct request_queue *q, struct blk_trace *bt)
 315 {
 316         relay_close(bt->rchan);
 317
 318         /*
 319          * If 'bt->dir' is not set, then both 'dropped' and 'msg' are created
 320          * under 'q->debugfs_dir', thus lookup and remove them.
 321          */
 322         if (!bt->dir) {
 323                 debugfs_lookup_and_remove("dropped", q->debugfs_dir);
 324                 debugfs_lookup_and_remove("msg", q->debugfs_dir);
 325         } else {
 326                 debugfs_remove(bt->dir);
 327         }
 328         free_percpu(bt->sequence);
 329         free_percpu(bt->msg_data);
 330         kfree(bt);
 331 }
 332
 333 static void get_probe_ref(void)
 334 {
 335         mutex_lock(&blk_probe_mutex);
 336         if (++blk_probes_ref == 1)
 337                 blk_register_tracepoints();
 338         mutex_unlock(&blk_probe_mutex);
 339 }
 340
 341 static void put_probe_ref(void)
 342 {
 343         mutex_lock(&blk_probe_mutex);
 344         if (!--blk_probes_ref)
 345                 blk_unregister_tracepoints();
 346         mutex_unlock(&blk_probe_mutex);
 347 }
 348
 349 static int blk_trace_start(struct blk_trace *bt)
 350 {
 351         if (bt->trace_state != Blktrace_setup &&
 352             bt->trace_state != Blktrace_stopped)
 353                 return -EINVAL;
 354
 355         blktrace_seq++;
 356         smp_mb();
 357         bt->trace_state = Blktrace_running;
 358         raw_spin_lock_irq(&running_trace_lock);
 359         list_add(&bt->running_list, &running_trace_list);
 360         raw_spin_unlock_irq(&running_trace_lock);
 361         trace_note_time(bt);
 362
 363         return 0;
 364 }
 365
 366 static int blk_trace_stop(struct blk_trace *bt)
 367 {
 368         if (bt->trace_state != Blktrace_running)
 369                 return -EINVAL;
 370
 371         bt->trace_state = Blktrace_stopped;
 372         raw_spin_lock_irq(&running_trace_lock);
 373         list_del_init(&bt->running_list);
 374         raw_spin_unlock_irq(&running_trace_lock);
 375         relay_flush(bt->rchan);
 376
 377         return 0;
 378 }
 379
 380 static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt)
 381 {
 382         blk_trace_stop(bt);
 383         synchronize_rcu();
 384         blk_trace_free(q, bt);
 385         put_probe_ref();
 386 }
 387
 388 static int __blk_trace_remove(struct request_queue *q)
 389 {
 390         struct blk_trace *bt;
 391
 392         bt = rcu_replace_pointer(q->blk_trace, NULL,
 393                                  lockdep_is_held(&q->debugfs_mutex));
 394         if (!bt)
 395                 return -EINVAL;
 396
 397         blk_trace_cleanup(q, bt);
 398
 399         return 0;
 400 }
 401
 402 int blk_trace_remove(struct request_queue *q)
 403 {
 404         int ret;
 405
 406         mutex_lock(&q->debugfs_mutex);
 407         ret = __blk_trace_remove(q);
 408         mutex_unlock(&q->debugfs_mutex);
 409
 410         return ret;
 411 }
 412 EXPORT_SYMBOL_GPL(blk_trace_remove);
 413
 414 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
 415                                 size_t count, loff_t *ppos)
 416 {
 417         struct blk_trace *bt = filp->private_data;
 418         char buf[16];
 419
 420         snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
 421
 422         return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
 423 }
 424
 425 static const struct file_operations blk_dropped_fops = {
 426         .owner =        THIS_MODULE,
 427         .open =         simple_open,
 428         .read =         blk_dropped_read,
 429         .llseek =       default_llseek,
 430 };
 431
 432 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
 433                                 size_t count, loff_t *ppos)
 434 {
 435         char *msg;
 436         struct blk_trace *bt;
 437
 438         if (count >= BLK_TN_MAX_MSG)
 439                 return -EINVAL;
 440
 441         msg = memdup_user_nul(buffer, count);
 442         if (IS_ERR(msg))
 443                 return PTR_ERR(msg);
 444
 445         bt = filp->private_data;
 446         __blk_trace_note_message(bt, NULL, "%s", msg);
 447         kfree(msg);
 448
 449         return count;
 450 }
 451
 452 static const struct file_operations blk_msg_fops = {
 453         .owner =        THIS_MODULE,
 454         .open =         simple_open,
 455         .write =        blk_msg_write,
 456         .llseek =       noop_llseek,
 457 };
 458
 459 /*
 460  * Keep track of how many times we encountered a full subbuffer, to aid
 461  * the user space app in telling how many lost events there were.
 462  */
 463 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
 464                                      void *prev_subbuf, size_t prev_padding)
 465 {
 466         struct blk_trace *bt;
 467
 468         if (!relay_buf_full(buf))
 469                 return 1;
 470
 471         bt = buf->chan->private_data;
 472         atomic_inc(&bt->dropped);
 473         return 0;
 474 }
 475
 476 static int blk_remove_buf_file_callback(struct dentry *dentry)
 477 {
 478         debugfs_remove(dentry);
 479
 480         return 0;
 481 }
 482
 483 static struct dentry *blk_create_buf_file_callback(const char *filename,
 484                                                    struct dentry *parent,
 485                                                    umode_t mode,
 486                                                    struct rchan_buf *buf,
 487                                                    int *is_global)
 488 {
 489         return debugfs_create_file(filename, mode, parent, buf,
 490                                         &relay_file_operations);
 491 }
 492
 493 static const struct rchan_callbacks blk_relay_callbacks = {
 494         .subbuf_start           = blk_subbuf_start_callback,
 495         .create_buf_file        = blk_create_buf_file_callback,
 496         .remove_buf_file        = blk_remove_buf_file_callback,
 497 };
 498
 499 static void blk_trace_setup_lba(struct blk_trace *bt,
 500                                 struct block_device *bdev)
 501 {
 502         if (bdev) {
 503                 bt->start_lba = bdev->bd_start_sect;
 504                 bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev);
 505         } else {
 506                 bt->start_lba = 0;
 507                 bt->end_lba = -1ULL;
 508         }
 509 }
 510
 511 /*
 512  * Setup everything required to start tracing
 513  */
 514 static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 515                               struct block_device *bdev,
 516                               struct blk_user_trace_setup *buts)
 517 {
 518         struct blk_trace *bt = NULL;
 519         struct dentry *dir = NULL;
 520         int ret;
 521
 522         lockdep_assert_held(&q->debugfs_mutex);
 523
 524         if (!buts->buf_size || !buts->buf_nr)
 525                 return -EINVAL;
 526
 527         strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
 528         buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
 529
 530         /*
 531          * some device names have larger paths - convert the slashes
 532          * to underscores for this to work as expected
 533          */
 534         strreplace(buts->name, '/', '_');
 535
 536         /*
 537          * bdev can be NULL, as with scsi-generic, this is a helpful as
 538          * we can be.
 539          */
 540         if (rcu_dereference_protected(q->blk_trace,
 541                                       lockdep_is_held(&q->debugfs_mutex))) {
 542                 pr_warn("Concurrent blktraces are not allowed on %s\n",
 543                         buts->name);
 544                 return -EBUSY;
 545         }
 546
 547         bt = kzalloc(sizeof(*bt), GFP_KERNEL);
 548         if (!bt)
 549                 return -ENOMEM;
 550
 551         ret = -ENOMEM;
 552         bt->sequence = alloc_percpu(unsigned long);
 553         if (!bt->sequence)
 554                 goto err;
 555
 556         bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
 557         if (!bt->msg_data)
 558                 goto err;
 559
 560         /*
 561          * When tracing the whole disk reuse the existing debugfs directory
 562          * created by the block layer on init. For partitions block devices,
 563          * and scsi-generic block devices we create a temporary new debugfs
 564          * directory that will be removed once the trace ends.
 565          */
 566         if (bdev && !bdev_is_partition(bdev))
 567                 dir = q->debugfs_dir;
 568         else
 569                 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
 570
 571         /*
 572          * As blktrace relies on debugfs for its interface the debugfs directory
 573          * is required, contrary to the usual mantra of not checking for debugfs
 574          * files or directories.
 575          */
 576         if (IS_ERR_OR_NULL(dir)) {
 577                 pr_warn("debugfs_dir not present for %s so skipping\n",
 578                         buts->name);
 579                 ret = -ENOENT;
 580                 goto err;
 581         }
 582
 583         bt->dev = dev;
 584         atomic_set(&bt->dropped, 0);
 585         INIT_LIST_HEAD(&bt->running_list);
 586
 587         ret = -EIO;
 588         debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
 589         debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
 590
 591         bt->rchan = relay_open("trace", dir, buts->buf_size,
 592                                 buts->buf_nr, &blk_relay_callbacks, bt);
 593         if (!bt->rchan)
 594                 goto err;
 595
 596         bt->act_mask = buts->act_mask;
 597         if (!bt->act_mask)
 598                 bt->act_mask = (u16) -1;
 599
 600         blk_trace_setup_lba(bt, bdev);
 601
 602         /* overwrite with user settings */
 603         if (buts->start_lba)
 604                 bt->start_lba = buts->start_lba;
 605         if (buts->end_lba)
 606                 bt->end_lba = buts->end_lba;
 607
 608         bt->pid = buts->pid;
 609         bt->trace_state = Blktrace_setup;
 610
 611         rcu_assign_pointer(q->blk_trace, bt);
 612         get_probe_ref();
 613
 614         ret = 0;
 615 err:
 616         if (ret)
 617                 blk_trace_free(q, bt);
 618         return ret;
 619 }
 620
 621 static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 622                              struct block_device *bdev, char __user *arg)
 623 {
 624         struct blk_user_trace_setup buts;
 625         int ret;
 626
 627         ret = copy_from_user(&buts, arg, sizeof(buts));
 628         if (ret)
 629                 return -EFAULT;
 630
 631         ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
 632         if (ret)
 633                 return ret;
 634
 635         if (copy_to_user(arg, &buts, sizeof(buts))) {
 636                 __blk_trace_remove(q);
 637                 return -EFAULT;
 638         }
 639         return 0;
 640 }
 641
 642 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 643                     struct block_device *bdev,
 644                     char __user *arg)
 645 {
 646         int ret;
 647
 648         mutex_lock(&q->debugfs_mutex);
 649         ret = __blk_trace_setup(q, name, dev, bdev, arg);
 650         mutex_unlock(&q->debugfs_mutex);
 651
 652         return ret;
 653 }
 654 EXPORT_SYMBOL_GPL(blk_trace_setup);
 655
 656 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
 657 static int compat_blk_trace_setup(struct request_queue *q, char *name,
 658                                   dev_t dev, struct block_device *bdev,
 659                                   char __user *arg)
 660 {
 661         struct blk_user_trace_setup buts;
 662         struct compat_blk_user_trace_setup cbuts;
 663         int ret;
 664
 665         if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
 666                 return -EFAULT;
 667
 668         buts = (struct blk_user_trace_setup) {
 669                 .act_mask = cbuts.act_mask,
 670                 .buf_size = cbuts.buf_size,
 671                 .buf_nr = cbuts.buf_nr,
 672                 .start_lba = cbuts.start_lba,
 673                 .end_lba = cbuts.end_lba,
 674                 .pid = cbuts.pid,
 675         };
 676
 677         ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
 678         if (ret)
 679                 return ret;
 680
 681         if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
 682                 __blk_trace_remove(q);
 683                 return -EFAULT;
 684         }
 685
 686         return 0;
 687 }
 688 #endif
 689
 690 static int __blk_trace_startstop(struct request_queue *q, int start)
 691 {
 692         struct blk_trace *bt;
 693
 694         bt = rcu_dereference_protected(q->blk_trace,
 695                                        lockdep_is_held(&q->debugfs_mutex));
 696         if (bt == NULL)
 697                 return -EINVAL;
 698
 699         if (start)
 700                 return blk_trace_start(bt);
 701         else
 702                 return blk_trace_stop(bt);
 703 }
 704
 705 int blk_trace_startstop(struct request_queue *q, int start)
 706 {
 707         int ret;
 708
 709         mutex_lock(&q->debugfs_mutex);
 710         ret = __blk_trace_startstop(q, start);
 711         mutex_unlock(&q->debugfs_mutex);
 712
 713         return ret;
 714 }
 715 EXPORT_SYMBOL_GPL(blk_trace_startstop);
 716
 717 /*
 718  * When reading or writing the blktrace sysfs files, the references to the
 719  * opened sysfs or device files should prevent the underlying block device
 720  * from being removed. So no further delete protection is really needed.
 721  */
 722
 723 /**
 724  * blk_trace_ioctl - handle the ioctls associated with tracing
 725  * @bdev:       the block device
 726  * @cmd:        the ioctl cmd
 727  * @arg:        the argument data, if any
 728  *
 729  **/
 730 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 731 {
 732         struct request_queue *q = bdev_get_queue(bdev);
 733         int ret, start = 0;
 734         char b[BDEVNAME_SIZE];
 735
 736         mutex_lock(&q->debugfs_mutex);
 737
 738         switch (cmd) {
 739         case BLKTRACESETUP:
 740                 snprintf(b, sizeof(b), "%pg", bdev);
 741                 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
 742                 break;
 743 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
 744         case BLKTRACESETUP32:
 745                 snprintf(b, sizeof(b), "%pg", bdev);
 746                 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
 747                 break;
 748 #endif
 749         case BLKTRACESTART:
 750                 start = 1;
 751                 fallthrough;
 752         case BLKTRACESTOP:
 753                 ret = __blk_trace_startstop(q, start);
 754                 break;
 755         case BLKTRACETEARDOWN:
 756                 ret = __blk_trace_remove(q);
 757                 break;
 758         default:
 759                 ret = -ENOTTY;
 760                 break;
 761         }
 762
 763         mutex_unlock(&q->debugfs_mutex);
 764         return ret;
 765 }
 766
 767 /**
 768  * blk_trace_shutdown - stop and cleanup trace structures
 769  * @q:    the request queue associated with the device
 770  *
 771  **/
 772 void blk_trace_shutdown(struct request_queue *q)
 773 {
 774         if (rcu_dereference_protected(q->blk_trace,
 775                                       lockdep_is_held(&q->debugfs_mutex)))
 776                 __blk_trace_remove(q);
 777 }
 778
 779 #ifdef CONFIG_BLK_CGROUP
 780 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
 781 {
 782         struct cgroup_subsys_state *blkcg_css;
 783         struct blk_trace *bt;
 784
 785         /* We don't use the 'bt' value here except as an optimization... */
 786         bt = rcu_dereference_protected(q->blk_trace, 1);
 787         if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
 788                 return 0;
 789
 790         blkcg_css = bio_blkcg_css(bio);
 791         if (!blkcg_css)
 792                 return 0;
 793         return cgroup_id(blkcg_css->cgroup);
 794 }
 795 #else
 796 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
 797 {
 798         return 0;
 799 }
 800 #endif
 801
 802 static u64
 803 blk_trace_request_get_cgid(struct request *rq)
 804 {
 805         if (!rq->bio)
 806                 return 0;
 807         /* Use the first bio */
 808         return blk_trace_bio_get_cgid(rq->q, rq->bio);
 809 }
 810
 811 /*
 812  * blktrace probes
 813  */
 814
 815 /**
 816  * blk_add_trace_rq - Add a trace for a request oriented action
 817  * @rq:         the source request
 818  * @error:      return status to log
 819  * @nr_bytes:   number of completed bytes
 820  * @what:       the action
 821  * @cgid:       the cgroup info
 822  *
 823  * Description:
 824  *     Records an action against a request. Will log the bio offset + size.
 825  *
 826  **/
 827 static void blk_add_trace_rq(struct request *rq, blk_status_t error,
 828                              unsigned int nr_bytes, u32 what, u64 cgid)
 829 {
 830         struct blk_trace *bt;
 831
 832         rcu_read_lock();
 833         bt = rcu_dereference(rq->q->blk_trace);
 834         if (likely(!bt)) {
 835                 rcu_read_unlock();
 836                 return;
 837         }
 838
 839         if (blk_rq_is_passthrough(rq))
 840                 what |= BLK_TC_ACT(BLK_TC_PC);
 841         else
 842                 what |= BLK_TC_ACT(BLK_TC_FS);
 843
 844         __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, rq->cmd_flags,
 845                         what, blk_status_to_errno(error), 0, NULL, cgid);
 846         rcu_read_unlock();
 847 }
 848
 849 static void blk_add_trace_rq_insert(void *ignore, struct request *rq)
 850 {
 851         blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
 852                          blk_trace_request_get_cgid(rq));
 853 }
 854
 855 static void blk_add_trace_rq_issue(void *ignore, struct request *rq)
 856 {
 857         blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
 858                          blk_trace_request_get_cgid(rq));
 859 }
 860
 861 static void blk_add_trace_rq_merge(void *ignore, struct request *rq)
 862 {
 863         blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
 864                          blk_trace_request_get_cgid(rq));
 865 }
 866
 867 static void blk_add_trace_rq_requeue(void *ignore, struct request *rq)
 868 {
 869         blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
 870                          blk_trace_request_get_cgid(rq));
 871 }
 872
 873 static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
 874                         blk_status_t error, unsigned int nr_bytes)
 875 {
 876         blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
 877                          blk_trace_request_get_cgid(rq));
 878 }
 879
 880 /**
 881  * blk_add_trace_bio - Add a trace for a bio oriented action
 882  * @q:          queue the io is for
 883  * @bio:        the source bio
 884  * @what:       the action
 885  * @error:      error, if any
 886  *
 887  * Description:
 888  *     Records an action against a bio. Will log the bio offset + size.
 889  *
 890  **/
 891 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
 892                               u32 what, int error)
 893 {
 894         struct blk_trace *bt;
 895
 896         rcu_read_lock();
 897         bt = rcu_dereference(q->blk_trace);
 898         if (likely(!bt)) {
 899                 rcu_read_unlock();
 900                 return;
 901         }
 902
 903         __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
 904                         bio->bi_opf, what, error, 0, NULL,
 905                         blk_trace_bio_get_cgid(q, bio));
 906         rcu_read_unlock();
 907 }
 908
 909 static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio)
 910 {
 911         blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0);
 912 }
 913
 914 static void blk_add_trace_bio_complete(void *ignore,
 915                                        struct request_queue *q, struct bio *bio)
 916 {
 917         blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
 918                           blk_status_to_errno(bio->bi_status));
 919 }
 920
 921 static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio)
 922 {
 923         blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE,
 924                         0);
 925 }
 926
 927 static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio)
 928 {
 929         blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE,
 930                         0);
 931 }
 932
 933 static void blk_add_trace_bio_queue(void *ignore, struct bio *bio)
 934 {
 935         blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0);
 936 }
 937
 938 static void blk_add_trace_getrq(void *ignore, struct bio *bio)
 939 {
 940         blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0);
 941 }
 942
 943 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
 944 {
 945         struct blk_trace *bt;
 946
 947         rcu_read_lock();
 948         bt = rcu_dereference(q->blk_trace);
 949         if (bt)
 950                 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
 951         rcu_read_unlock();
 952 }
 953
 954 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
 955                                     unsigned int depth, bool explicit)
 956 {
 957         struct blk_trace *bt;
 958
 959         rcu_read_lock();
 960         bt = rcu_dereference(q->blk_trace);
 961         if (bt) {
 962                 __be64 rpdu = cpu_to_be64(depth);
 963                 u32 what;
 964
 965                 if (explicit)
 966                         what = BLK_TA_UNPLUG_IO;
 967                 else
 968                         what = BLK_TA_UNPLUG_TIMER;
 969
 970                 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
 971         }
 972         rcu_read_unlock();
 973 }
 974
 975 static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
 976 {
 977         struct request_queue *q = bio->bi_bdev->bd_disk->queue;
 978         struct blk_trace *bt;
 979
 980         rcu_read_lock();
 981         bt = rcu_dereference(q->blk_trace);
 982         if (bt) {
 983                 __be64 rpdu = cpu_to_be64(pdu);
 984
 985                 __blk_add_trace(bt, bio->bi_iter.bi_sector,
 986                                 bio->bi_iter.bi_size, bio->bi_opf, BLK_TA_SPLIT,
 987                                 blk_status_to_errno(bio->bi_status),
 988                                 sizeof(rpdu), &rpdu,
 989                                 blk_trace_bio_get_cgid(q, bio));
 990         }
 991         rcu_read_unlock();
 992 }
 993
 994 /**
 995  * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
 996  * @ignore:     trace callback data parameter (not used)
 997  * @bio:        the source bio
 998  * @dev:        source device
 999  * @from:       source sector
1000  *
1001  * Called after a bio is remapped to a different device and/or sector.
1002  **/
1003 static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev,
1004                                     sector_t from)
1005 {
1006         struct request_queue *q = bio->bi_bdev->bd_disk->queue;
1007         struct blk_trace *bt;
1008         struct blk_io_trace_remap r;
1009
1010         rcu_read_lock();
1011         bt = rcu_dereference(q->blk_trace);
1012         if (likely(!bt)) {
1013                 rcu_read_unlock();
1014                 return;
1015         }
1016
1017         r.device_from = cpu_to_be32(dev);
1018         r.device_to   = cpu_to_be32(bio_dev(bio));
1019         r.sector_from = cpu_to_be64(from);
1020
1021         __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1022                         bio->bi_opf, BLK_TA_REMAP,
1023                         blk_status_to_errno(bio->bi_status),
1024                         sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1025         rcu_read_unlock();
1026 }
1027
1028 /**
1029  * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1030  * @ignore:     trace callback data parameter (not used)
1031  * @rq:         the source request
1032  * @dev:        target device
1033  * @from:       source sector
1034  *
1035  * Description:
1036  *     Device mapper remaps request to other devices.
1037  *     Add a trace for that action.
1038  *
1039  **/
1040 static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev,
1041                                    sector_t from)
1042 {
1043         struct blk_trace *bt;
1044         struct blk_io_trace_remap r;
1045
1046         rcu_read_lock();
1047         bt = rcu_dereference(rq->q->blk_trace);
1048         if (likely(!bt)) {
1049                 rcu_read_unlock();
1050                 return;
1051         }
1052
1053         r.device_from = cpu_to_be32(dev);
1054         r.device_to   = cpu_to_be32(disk_devt(rq->q->disk));
1055         r.sector_from = cpu_to_be64(from);
1056
1057         __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1058                         rq->cmd_flags, BLK_TA_REMAP, 0,
1059                         sizeof(r), &r, blk_trace_request_get_cgid(rq));
1060         rcu_read_unlock();
1061 }
1062
1063 /**
1064  * blk_add_driver_data - Add binary message with driver-specific data
1065  * @rq:         io request
1066  * @data:       driver-specific data
1067  * @len:        length of driver-specific data
1068  *
1069  * Description:
1070  *     Some drivers might want to write driver-specific data per request.
1071  *
1072  **/
1073 void blk_add_driver_data(struct request *rq, void *data, size_t len)
1074 {
1075         struct blk_trace *bt;
1076
1077         rcu_read_lock();
1078         bt = rcu_dereference(rq->q->blk_trace);
1079         if (likely(!bt)) {
1080                 rcu_read_unlock();
1081                 return;
1082         }
1083
1084         __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0,
1085                                 BLK_TA_DRV_DATA, 0, len, data,
1086                                 blk_trace_request_get_cgid(rq));
1087         rcu_read_unlock();
1088 }
1089 EXPORT_SYMBOL_GPL(blk_add_driver_data);
1090
1091 static void blk_register_tracepoints(void)
1092 {
1093         int ret;
1094
1095         ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1096         WARN_ON(ret);
1097         ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1098         WARN_ON(ret);
1099         ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1100         WARN_ON(ret);
1101         ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1102         WARN_ON(ret);
1103         ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1104         WARN_ON(ret);
1105         ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1106         WARN_ON(ret);
1107         ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1108         WARN_ON(ret);
1109         ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1110         WARN_ON(ret);
1111         ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1112         WARN_ON(ret);
1113         ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1114         WARN_ON(ret);
1115         ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1116         WARN_ON(ret);
1117         ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1118         WARN_ON(ret);
1119         ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1120         WARN_ON(ret);
1121         ret = register_trace_block_split(blk_add_trace_split, NULL);
1122         WARN_ON(ret);
1123         ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1124         WARN_ON(ret);
1125         ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1126         WARN_ON(ret);
1127 }
1128
1129 static void blk_unregister_tracepoints(void)
1130 {
1131         unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1132         unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1133         unregister_trace_block_split(blk_add_trace_split, NULL);
1134         unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1135         unregister_trace_block_plug(blk_add_trace_plug, NULL);
1136         unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1137         unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1138         unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1139         unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1140         unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1141         unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1142         unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1143         unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1144         unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1145         unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1146         unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1147
1148         tracepoint_synchronize_unregister();
1149 }
1150
1151 /*
1152  * struct blk_io_tracer formatting routines
1153  */
1154
1155 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1156 {
1157         int i = 0;
1158         int tc = t->action >> BLK_TC_SHIFT;
1159
1160         if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1161                 rwbs[i++] = 'N';
1162                 goto out;
1163         }
1164
1165         if (tc & BLK_TC_FLUSH)
1166                 rwbs[i++] = 'F';
1167
1168         if (tc & BLK_TC_DISCARD)
1169                 rwbs[i++] = 'D';
1170         else if (tc & BLK_TC_WRITE)
1171                 rwbs[i++] = 'W';
1172         else if (t->bytes)
1173                 rwbs[i++] = 'R';
1174         else
1175                 rwbs[i++] = 'N';
1176
1177         if (tc & BLK_TC_FUA)
1178                 rwbs[i++] = 'F';
1179         if (tc & BLK_TC_AHEAD)
1180                 rwbs[i++] = 'A';
1181         if (tc & BLK_TC_SYNC)
1182                 rwbs[i++] = 'S';
1183         if (tc & BLK_TC_META)
1184                 rwbs[i++] = 'M';
1185 out:
1186         rwbs[i] = '\0';
1187 }
1188
1189 static inline
1190 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1191 {
1192         return (const struct blk_io_trace *)ent;
1193 }
1194
1195 static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1196 {
1197         return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
1198 }
1199
1200 static inline u64 t_cgid(const struct trace_entry *ent)
1201 {
1202         return *(u64 *)(te_blk_io_trace(ent) + 1);
1203 }
1204
1205 static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1206 {
1207         return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
1208 }
1209
1210 static inline u32 t_action(const struct trace_entry *ent)
1211 {
1212         return te_blk_io_trace(ent)->action;
1213 }
1214
1215 static inline u32 t_bytes(const struct trace_entry *ent)
1216 {
1217         return te_blk_io_trace(ent)->bytes;
1218 }
1219
1220 static inline u32 t_sec(const struct trace_entry *ent)
1221 {
1222         return te_blk_io_trace(ent)->bytes >> 9;
1223 }
1224
1225 static inline unsigned long long t_sector(const struct trace_entry *ent)
1226 {
1227         return te_blk_io_trace(ent)->sector;
1228 }
1229
1230 static inline __u16 t_error(const struct trace_entry *ent)
1231 {
1232         return te_blk_io_trace(ent)->error;
1233 }
1234
1235 static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1236 {
1237         const __be64 *val = pdu_start(ent, has_cg);
1238         return be64_to_cpu(*val);
1239 }
1240
1241 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1242         bool has_cg);
1243
1244 static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1245         bool has_cg)
1246 {
1247         char rwbs[RWBS_LEN];
1248         unsigned long long ts  = iter->ts;
1249         unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1250         unsigned secs          = (unsigned long)ts;
1251         const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1252
1253         fill_rwbs(rwbs, t);
1254
1255         trace_seq_printf(&iter->seq,
1256                          "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1257                          MAJOR(t->device), MINOR(t->device), iter->cpu,
1258                          secs, nsec_rem, iter->ent->pid, act, rwbs);
1259 }
1260
1261 static void blk_log_action(struct trace_iterator *iter, const char *act,
1262         bool has_cg)
1263 {
1264         char rwbs[RWBS_LEN];
1265         const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1266
1267         fill_rwbs(rwbs, t);
1268         if (has_cg) {
1269                 u64 id = t_cgid(iter->ent);
1270
1271                 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1272                         char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1273
1274                         cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1275                                 sizeof(blkcg_name_buf));
1276                         trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1277                                  MAJOR(t->device), MINOR(t->device),
1278                                  blkcg_name_buf, act, rwbs);
1279                 } else {
1280                         /*
1281                          * The cgid portion used to be "INO,GEN".  Userland
1282                          * builds a FILEID_INO32_GEN fid out of them and
1283                          * opens the cgroup using open_by_handle_at(2).
1284                          * While 32bit ino setups are still the same, 64bit
1285                          * ones now use the 64bit ino as the whole ID and
1286                          * no longer use generation.
1287                          *
1288                          * Regardless of the content, always output
1289                          * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
1290                          * be mapped back to @id on both 64 and 32bit ino
1291                          * setups.  See __kernfs_fh_to_dentry().
1292                          */
1293                         trace_seq_printf(&iter->seq,
1294                                  "%3d,%-3d %llx,%-llx %2s %3s ",
1295                                  MAJOR(t->device), MINOR(t->device),
1296                                  id & U32_MAX, id >> 32, act, rwbs);
1297                 }
1298         } else
1299                 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1300                                  MAJOR(t->device), MINOR(t->device), act, rwbs);
1301 }
1302
1303 static void blk_log_dump_pdu(struct trace_seq *s,
1304         const struct trace_entry *ent, bool has_cg)
1305 {
1306         const unsigned char *pdu_buf;
1307         int pdu_len;
1308         int i, end;
1309
1310         pdu_buf = pdu_start(ent, has_cg);
1311         pdu_len = pdu_real_len(ent, has_cg);
1312
1313         if (!pdu_len)
1314                 return;
1315
1316         /* find the last zero that needs to be printed */
1317         for (end = pdu_len - 1; end >= 0; end--)
1318                 if (pdu_buf[end])
1319                         break;
1320         end++;
1321
1322         trace_seq_putc(s, '(');
1323
1324         for (i = 0; i < pdu_len; i++) {
1325
1326                 trace_seq_printf(s, "%s%02x",
1327                                  i == 0 ? "" : " ", pdu_buf[i]);
1328
1329                 /*
1330                  * stop when the rest is just zeros and indicate so
1331                  * with a ".." appended
1332                  */
1333                 if (i == end && end != pdu_len - 1) {
1334                         trace_seq_puts(s, " ..) ");
1335                         return;
1336                 }
1337         }
1338
1339         trace_seq_puts(s, ") ");
1340 }
1341
1342 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1343 {
1344         char cmd[TASK_COMM_LEN];
1345
1346         trace_find_cmdline(ent->pid, cmd);
1347
1348         if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1349                 trace_seq_printf(s, "%u ", t_bytes(ent));
1350                 blk_log_dump_pdu(s, ent, has_cg);
1351                 trace_seq_printf(s, "[%s]\n", cmd);
1352         } else {
1353                 if (t_sec(ent))
1354                         trace_seq_printf(s, "%llu + %u [%s]\n",
1355                                                 t_sector(ent), t_sec(ent), cmd);
1356                 else
1357                         trace_seq_printf(s, "[%s]\n", cmd);
1358         }
1359 }
1360
1361 static void blk_log_with_error(struct trace_seq *s,
1362                               const struct trace_entry *ent, bool has_cg)
1363 {
1364         if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1365                 blk_log_dump_pdu(s, ent, has_cg);
1366                 trace_seq_printf(s, "[%d]\n", t_error(ent));
1367         } else {
1368                 if (t_sec(ent))
1369                         trace_seq_printf(s, "%llu + %u [%d]\n",
1370                                          t_sector(ent),
1371                                          t_sec(ent), t_error(ent));
1372                 else
1373                         trace_seq_printf(s, "%llu [%d]\n",
1374                                          t_sector(ent), t_error(ent));
1375         }
1376 }
1377
1378 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1379 {
1380         const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1381
1382         trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1383                          t_sector(ent), t_sec(ent),
1384                          MAJOR(be32_to_cpu(__r->device_from)),
1385                          MINOR(be32_to_cpu(__r->device_from)),
1386                          be64_to_cpu(__r->sector_from));
1387 }
1388
1389 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1390 {
1391         char cmd[TASK_COMM_LEN];
1392
1393         trace_find_cmdline(ent->pid, cmd);
1394
1395         trace_seq_printf(s, "[%s]\n", cmd);
1396 }
1397
1398 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1399 {
1400         char cmd[TASK_COMM_LEN];
1401
1402         trace_find_cmdline(ent->pid, cmd);
1403
1404         trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1405 }
1406
1407 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1408 {
1409         char cmd[TASK_COMM_LEN];
1410
1411         trace_find_cmdline(ent->pid, cmd);
1412
1413         trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1414                          get_pdu_int(ent, has_cg), cmd);
1415 }
1416
1417 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1418                         bool has_cg)
1419 {
1420
1421         trace_seq_putmem(s, pdu_start(ent, has_cg),
1422                 pdu_real_len(ent, has_cg));
1423         trace_seq_putc(s, '\n');
1424 }
1425
1426 /*
1427  * struct tracer operations
1428  */
1429
1430 static void blk_tracer_print_header(struct seq_file *m)
1431 {
1432         if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1433                 return;
1434         seq_puts(m, "# DEV   CPU TIMESTAMP     PID ACT FLG\n"
1435                     "#  |     |     |           |   |   |\n");
1436 }
1437
1438 static void blk_tracer_start(struct trace_array *tr)
1439 {
1440         blk_tracer_enabled = true;
1441 }
1442
1443 static int blk_tracer_init(struct trace_array *tr)
1444 {
1445         blk_tr = tr;
1446         blk_tracer_start(tr);
1447         return 0;
1448 }
1449
1450 static void blk_tracer_stop(struct trace_array *tr)
1451 {
1452         blk_tracer_enabled = false;
1453 }
1454
1455 static void blk_tracer_reset(struct trace_array *tr)
1456 {
1457         blk_tracer_stop(tr);
1458 }
1459
1460 static const struct {
1461         const char *act[2];
1462         void       (*print)(struct trace_seq *s, const struct trace_entry *ent,
1463                             bool has_cg);
1464 } what2act[] = {
1465         [__BLK_TA_QUEUE]        = {{  "Q", "queue" },      blk_log_generic },
1466         [__BLK_TA_BACKMERGE]    = {{  "M", "backmerge" },  blk_log_generic },
1467         [__BLK_TA_FRONTMERGE]   = {{  "F", "frontmerge" }, blk_log_generic },
1468         [__BLK_TA_GETRQ]        = {{  "G", "getrq" },      blk_log_generic },
1469         [__BLK_TA_SLEEPRQ]      = {{  "S", "sleeprq" },    blk_log_generic },
1470         [__BLK_TA_REQUEUE]      = {{  "R", "requeue" },    blk_log_with_error },
1471         [__BLK_TA_ISSUE]        = {{  "D", "issue" },      blk_log_generic },
1472         [__BLK_TA_COMPLETE]     = {{  "C", "complete" },   blk_log_with_error },
1473         [__BLK_TA_PLUG]         = {{  "P", "plug" },       blk_log_plug },
1474         [__BLK_TA_UNPLUG_IO]    = {{  "U", "unplug_io" },  blk_log_unplug },
1475         [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1476         [__BLK_TA_INSERT]       = {{  "I", "insert" },     blk_log_generic },
1477         [__BLK_TA_SPLIT]        = {{  "X", "split" },      blk_log_split },
1478         [__BLK_TA_BOUNCE]       = {{  "B", "bounce" },     blk_log_generic },
1479         [__BLK_TA_REMAP]        = {{  "A", "remap" },      blk_log_remap },
1480 };
1481
1482 static enum print_line_t print_one_line(struct trace_iterator *iter,
1483                                         bool classic)
1484 {
1485         struct trace_array *tr = iter->tr;
1486         struct trace_seq *s = &iter->seq;
1487         const struct blk_io_trace *t;
1488         u16 what;
1489         bool long_act;
1490         blk_log_action_t *log_action;
1491         bool has_cg;
1492
1493         t          = te_blk_io_trace(iter->ent);
1494         what       = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1495         long_act   = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1496         log_action = classic ? &blk_log_action_classic : &blk_log_action;
1497         has_cg     = t->action & __BLK_TA_CGROUP;
1498
1499         if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1500                 log_action(iter, long_act ? "message" : "m", has_cg);
1501                 blk_log_msg(s, iter->ent, has_cg);
1502                 return trace_handle_return(s);
1503         }
1504
1505         if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1506                 trace_seq_printf(s, "Unknown action %x\n", what);
1507         else {
1508                 log_action(iter, what2act[what].act[long_act], has_cg);
1509                 what2act[what].print(s, iter->ent, has_cg);
1510         }
1511
1512         return trace_handle_return(s);
1513 }
1514
1515 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1516                                                int flags, struct trace_event *event)
1517 {
1518         return print_one_line(iter, false);
1519 }
1520
1521 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1522 {
1523         struct trace_seq *s = &iter->seq;
1524         struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1525         const int offset = offsetof(struct blk_io_trace, sector);
1526         struct blk_io_trace old = {
1527                 .magic    = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1528                 .time     = iter->ts,
1529         };
1530
1531         trace_seq_putmem(s, &old, offset);
1532         trace_seq_putmem(s, &t->sector,
1533                          sizeof(old) - offset + t->pdu_len);
1534 }
1535
1536 static enum print_line_t
1537 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1538                              struct trace_event *event)
1539 {
1540         blk_trace_synthesize_old_trace(iter);
1541
1542         return trace_handle_return(&iter->seq);
1543 }
1544
1545 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1546 {
1547         if ((iter->ent->type != TRACE_BLK) ||
1548             !(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1549                 return TRACE_TYPE_UNHANDLED;
1550
1551         return print_one_line(iter, true);
1552 }
1553
1554 static int
1555 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1556 {
1557         /* don't output context-info for blk_classic output */
1558         if (bit == TRACE_BLK_OPT_CLASSIC) {
1559                 if (set)
1560                         tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1561                 else
1562                         tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1563         }
1564         return 0;
1565 }
1566
1567 static struct tracer blk_tracer __read_mostly = {
1568         .name           = "blk",
1569         .init           = blk_tracer_init,
1570         .reset          = blk_tracer_reset,
1571         .start          = blk_tracer_start,
1572         .stop           = blk_tracer_stop,
1573         .print_header   = blk_tracer_print_header,
1574         .print_line     = blk_tracer_print_line,
1575         .flags          = &blk_tracer_flags,
1576         .set_flag       = blk_tracer_set_flag,
1577 };
1578
1579 static struct trace_event_functions trace_blk_event_funcs = {
1580         .trace          = blk_trace_event_print,
1581         .binary         = blk_trace_event_print_binary,
1582 };
1583
1584 static struct trace_event trace_blk_event = {
1585         .type           = TRACE_BLK,
1586         .funcs          = &trace_blk_event_funcs,
1587 };
1588
1589 static int __init init_blk_tracer(void)
1590 {
1591         if (!register_trace_event(&trace_blk_event)) {
1592                 pr_warn("Warning: could not register block events\n");
1593                 return 1;
1594         }
1595
1596         if (register_tracer(&blk_tracer) != 0) {
1597                 pr_warn("Warning: could not register the block tracer\n");
1598                 unregister_trace_event(&trace_blk_event);
1599                 return 1;
1600         }
1601
1602         return 0;
1603 }
1604
1605 device_initcall(init_blk_tracer);
1606
1607 static int blk_trace_remove_queue(struct request_queue *q)
1608 {
1609         struct blk_trace *bt;
1610
1611         bt = rcu_replace_pointer(q->blk_trace, NULL,
1612                                  lockdep_is_held(&q->debugfs_mutex));
1613         if (bt == NULL)
1614                 return -EINVAL;
1615
1616         blk_trace_stop(bt);
1617
1618         put_probe_ref();
1619         synchronize_rcu();
1620         blk_trace_free(q, bt);
1621         return 0;
1622 }
1623
1624 /*
1625  * Setup everything required to start tracing
1626  */
1627 static int blk_trace_setup_queue(struct request_queue *q,
1628                                  struct block_device *bdev)
1629 {
1630         struct blk_trace *bt = NULL;
1631         int ret = -ENOMEM;
1632
1633         bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1634         if (!bt)
1635                 return -ENOMEM;
1636
1637         bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1638         if (!bt->msg_data)
1639                 goto free_bt;
1640
1641         bt->dev = bdev->bd_dev;
1642         bt->act_mask = (u16)-1;
1643
1644         blk_trace_setup_lba(bt, bdev);
1645
1646         rcu_assign_pointer(q->blk_trace, bt);
1647         get_probe_ref();
1648         return 0;
1649
1650 free_bt:
1651         blk_trace_free(q, bt);
1652         return ret;
1653 }
1654
1655 /*
1656  * sysfs interface to enable and configure tracing
1657  */
1658
1659 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1660                                          struct device_attribute *attr,
1661                                          char *buf);
1662 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1663                                           struct device_attribute *attr,
1664                                           const char *buf, size_t count);
1665 #define BLK_TRACE_DEVICE_ATTR(_name) \
1666         DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1667                     sysfs_blk_trace_attr_show, \
1668                     sysfs_blk_trace_attr_store)
1669
1670 static BLK_TRACE_DEVICE_ATTR(enable);
1671 static BLK_TRACE_DEVICE_ATTR(act_mask);
1672 static BLK_TRACE_DEVICE_ATTR(pid);
1673 static BLK_TRACE_DEVICE_ATTR(start_lba);
1674 static BLK_TRACE_DEVICE_ATTR(end_lba);
1675
1676 static struct attribute *blk_trace_attrs[] = {
1677         &dev_attr_enable.attr,
1678         &dev_attr_act_mask.attr,
1679         &dev_attr_pid.attr,
1680         &dev_attr_start_lba.attr,
1681         &dev_attr_end_lba.attr,
1682         NULL
1683 };
1684
1685 struct attribute_group blk_trace_attr_group = {
1686         .name  = "trace",
1687         .attrs = blk_trace_attrs,
1688 };
1689
1690 static const struct {
1691         int mask;
1692         const char *str;
1693 } mask_maps[] = {
1694         { BLK_TC_READ,          "read"          },
1695         { BLK_TC_WRITE,         "write"         },
1696         { BLK_TC_FLUSH,         "flush"         },
1697         { BLK_TC_SYNC,          "sync"          },
1698         { BLK_TC_QUEUE,         "queue"         },
1699         { BLK_TC_REQUEUE,       "requeue"       },
1700         { BLK_TC_ISSUE,         "issue"         },
1701         { BLK_TC_COMPLETE,      "complete"      },
1702         { BLK_TC_FS,            "fs"            },
1703         { BLK_TC_PC,            "pc"            },
1704         { BLK_TC_NOTIFY,        "notify"        },
1705         { BLK_TC_AHEAD,         "ahead"         },
1706         { BLK_TC_META,          "meta"          },
1707         { BLK_TC_DISCARD,       "discard"       },
1708         { BLK_TC_DRV_DATA,      "drv_data"      },
1709         { BLK_TC_FUA,           "fua"           },
1710 };
1711
1712 static int blk_trace_str2mask(const char *str)
1713 {
1714         int i;
1715         int mask = 0;
1716         char *buf, *s, *token;
1717
1718         buf = kstrdup(str, GFP_KERNEL);
1719         if (buf == NULL)
1720                 return -ENOMEM;
1721         s = strstrip(buf);
1722
1723         while (1) {
1724                 token = strsep(&s, ",");
1725                 if (token == NULL)
1726                         break;
1727
1728                 if (*token == '\0')
1729                         continue;
1730
1731                 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1732                         if (strcasecmp(token, mask_maps[i].str) == 0) {
1733                                 mask |= mask_maps[i].mask;
1734                                 break;
1735                         }
1736                 }
1737                 if (i == ARRAY_SIZE(mask_maps)) {
1738                         mask = -EINVAL;
1739                         break;
1740                 }
1741         }
1742         kfree(buf);
1743
1744         return mask;
1745 }
1746
1747 static ssize_t blk_trace_mask2str(char *buf, int mask)
1748 {
1749         int i;
1750         char *p = buf;
1751
1752         for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1753                 if (mask & mask_maps[i].mask) {
1754                         p += sprintf(p, "%s%s",
1755                                     (p == buf) ? "" : ",", mask_maps[i].str);
1756                 }
1757         }
1758         *p++ = '\n';
1759
1760         return p - buf;
1761 }
1762
1763 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1764                                          struct device_attribute *attr,
1765                                          char *buf)
1766 {
1767         struct block_device *bdev = dev_to_bdev(dev);
1768         struct request_queue *q = bdev_get_queue(bdev);
1769         struct blk_trace *bt;
1770         ssize_t ret = -ENXIO;
1771
1772         mutex_lock(&q->debugfs_mutex);
1773
1774         bt = rcu_dereference_protected(q->blk_trace,
1775                                        lockdep_is_held(&q->debugfs_mutex));
1776         if (attr == &dev_attr_enable) {
1777                 ret = sprintf(buf, "%u\n", !!bt);
1778                 goto out_unlock_bdev;
1779         }
1780
1781         if (bt == NULL)
1782                 ret = sprintf(buf, "disabled\n");
1783         else if (attr == &dev_attr_act_mask)
1784                 ret = blk_trace_mask2str(buf, bt->act_mask);
1785         else if (attr == &dev_attr_pid)
1786                 ret = sprintf(buf, "%u\n", bt->pid);
1787         else if (attr == &dev_attr_start_lba)
1788                 ret = sprintf(buf, "%llu\n", bt->start_lba);
1789         else if (attr == &dev_attr_end_lba)
1790                 ret = sprintf(buf, "%llu\n", bt->end_lba);
1791
1792 out_unlock_bdev:
1793         mutex_unlock(&q->debugfs_mutex);
1794         return ret;
1795 }
1796
1797 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1798                                           struct device_attribute *attr,
1799                                           const char *buf, size_t count)
1800 {
1801         struct block_device *bdev = dev_to_bdev(dev);
1802         struct request_queue *q = bdev_get_queue(bdev);
1803         struct blk_trace *bt;
1804         u64 value;
1805         ssize_t ret = -EINVAL;
1806
1807         if (count == 0)
1808                 goto out;
1809
1810         if (attr == &dev_attr_act_mask) {
1811                 if (kstrtoull(buf, 0, &value)) {
1812                         /* Assume it is a list of trace category names */
1813                         ret = blk_trace_str2mask(buf);
1814                         if (ret < 0)
1815                                 goto out;
1816                         value = ret;
1817                 }
1818         } else {
1819                 if (kstrtoull(buf, 0, &value))
1820                         goto out;
1821         }
1822
1823         mutex_lock(&q->debugfs_mutex);
1824
1825         bt = rcu_dereference_protected(q->blk_trace,
1826                                        lockdep_is_held(&q->debugfs_mutex));
1827         if (attr == &dev_attr_enable) {
1828                 if (!!value == !!bt) {
1829                         ret = 0;
1830                         goto out_unlock_bdev;
1831                 }
1832                 if (value)
1833                         ret = blk_trace_setup_queue(q, bdev);
1834                 else
1835                         ret = blk_trace_remove_queue(q);
1836                 goto out_unlock_bdev;
1837         }
1838
1839         ret = 0;
1840         if (bt == NULL) {
1841                 ret = blk_trace_setup_queue(q, bdev);
1842                 bt = rcu_dereference_protected(q->blk_trace,
1843                                 lockdep_is_held(&q->debugfs_mutex));
1844         }
1845
1846         if (ret == 0) {
1847                 if (attr == &dev_attr_act_mask)
1848                         bt->act_mask = value;
1849                 else if (attr == &dev_attr_pid)
1850                         bt->pid = value;
1851                 else if (attr == &dev_attr_start_lba)
1852                         bt->start_lba = value;
1853                 else if (attr == &dev_attr_end_lba)
1854                         bt->end_lba = value;
1855         }
1856
1857 out_unlock_bdev:
1858         mutex_unlock(&q->debugfs_mutex);
1859 out:
1860         return ret ? ret : count;
1861 }
1862 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1863
1864 #ifdef CONFIG_EVENT_TRACING
1865
1866 /**
1867  * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string.
1868  * @rwbs:       buffer to be filled
1869  * @opf:        request operation type (REQ_OP_XXX) and flags for the tracepoint
1870  *
1871  * Description:
1872  *     Maps each request operation and flag to a single character and fills the
1873  *     buffer provided by the caller with resulting string.
1874  *
1875  **/
1876 void blk_fill_rwbs(char *rwbs, blk_opf_t opf)
1877 {
1878         int i = 0;
1879
1880         if (opf & REQ_PREFLUSH)
1881                 rwbs[i++] = 'F';
1882
1883         switch (opf & REQ_OP_MASK) {
1884         case REQ_OP_WRITE:
1885                 rwbs[i++] = 'W';
1886                 break;
1887         case REQ_OP_DISCARD:
1888                 rwbs[i++] = 'D';
1889                 break;
1890         case REQ_OP_SECURE_ERASE:
1891                 rwbs[i++] = 'D';
1892                 rwbs[i++] = 'E';
1893                 break;
1894         case REQ_OP_FLUSH:
1895                 rwbs[i++] = 'F';
1896                 break;
1897         case REQ_OP_READ:
1898                 rwbs[i++] = 'R';
1899                 break;
1900         default:
1901                 rwbs[i++] = 'N';
1902         }
1903
1904         if (opf & REQ_FUA)
1905                 rwbs[i++] = 'F';
1906         if (opf & REQ_RAHEAD)
1907                 rwbs[i++] = 'A';
1908         if (opf & REQ_SYNC)
1909                 rwbs[i++] = 'S';
1910         if (opf & REQ_META)
1911                 rwbs[i++] = 'M';
1912
1913         rwbs[i] = '\0';
1914 }
1915 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1916
1917 #endif /* CONFIG_EVENT_TRACING */
1918