1 /* 2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 16 * 17 */ 18 #include <linux/kernel.h> 19 #include <linux/blkdev.h> 20 #include <linux/blktrace_api.h> 21 #include <linux/percpu.h> 22 #include <linux/init.h> 23 #include <linux/mutex.h> 24 #include <linux/slab.h> 25 #include <linux/debugfs.h> 26 #include <linux/smp_lock.h> 27 #include <linux/time.h> 28 #include <linux/uaccess.h> 29 30 #include <trace/events/block.h> 31 32 #include "trace_output.h" 33 34 #ifdef CONFIG_BLK_DEV_IO_TRACE 35 36 static unsigned int blktrace_seq __read_mostly = 1; 37 38 static struct trace_array *blk_tr; 39 static bool blk_tracer_enabled __read_mostly; 40 41 /* Select an alternative, minimalistic output than the original one */ 42 #define TRACE_BLK_OPT_CLASSIC 0x1 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 { } 48 }; 49 50 static struct tracer_flags blk_tracer_flags = { 51 .val = 0, 52 .opts = blk_tracer_opts, 53 }; 54 55 /* Global reference count of probes */ 56 static atomic_t blk_probes_ref = ATOMIC_INIT(0); 57 58 static void blk_register_tracepoints(void); 59 static void blk_unregister_tracepoints(void); 60 61 /* 62 * Send out a notify message. 63 */ 64 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 65 const void *data, size_t len) 66 { 67 struct blk_io_trace *t; 68 struct ring_buffer_event *event = NULL; 69 struct ring_buffer *buffer = NULL; 70 int pc = 0; 71 int cpu = smp_processor_id(); 72 bool blk_tracer = blk_tracer_enabled; 73 74 if (blk_tracer) { 75 buffer = blk_tr->buffer; 76 pc = preempt_count(); 77 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 78 sizeof(*t) + len, 79 0, pc); 80 if (!event) 81 return; 82 t = ring_buffer_event_data(event); 83 goto record_it; 84 } 85 86 if (!bt->rchan) 87 return; 88 89 t = relay_reserve(bt->rchan, sizeof(*t) + len); 90 if (t) { 91 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 92 t->time = ktime_to_ns(ktime_get()); 93 record_it: 94 t->device = bt->dev; 95 t->action = action; 96 t->pid = pid; 97 t->cpu = cpu; 98 t->pdu_len = len; 99 memcpy((void *) t + sizeof(*t), data, len); 100 101 if (blk_tracer) 102 trace_buffer_unlock_commit(buffer, event, 0, pc); 103 } 104 } 105 106 /* 107 * Send out a notify for this process, if we haven't done so since a trace 108 * started 109 */ 110 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) 111 { 112 tsk->btrace_seq = blktrace_seq; 113 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm)); 114 } 115 116 static void trace_note_time(struct blk_trace *bt) 117 { 118 struct timespec now; 119 unsigned long flags; 120 u32 words[2]; 121 122 getnstimeofday(&now); 123 words[0] = now.tv_sec; 124 words[1] = now.tv_nsec; 125 126 local_irq_save(flags); 127 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); 128 local_irq_restore(flags); 129 } 130 131 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 132 { 133 int n; 134 va_list args; 135 unsigned long flags; 136 char *buf; 137 138 if (unlikely(bt->trace_state != Blktrace_running && 139 !blk_tracer_enabled)) 140 return; 141 142 local_irq_save(flags); 143 buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); 144 va_start(args, fmt); 145 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 146 va_end(args); 147 148 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); 149 local_irq_restore(flags); 150 } 151 EXPORT_SYMBOL_GPL(__trace_note_message); 152 153 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 154 pid_t pid) 155 { 156 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 157 return 1; 158 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 159 return 1; 160 if (bt->pid && pid != bt->pid) 161 return 1; 162 163 return 0; 164 } 165 166 /* 167 * Data direction bit lookup 168 */ 169 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 170 BLK_TC_ACT(BLK_TC_WRITE) }; 171 172 /* The ilog2() calls fall out because they're constant */ 173 #define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \ 174 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name)) 175 176 /* 177 * The worker for the various blk_add_trace*() types. Fills out a 178 * blk_io_trace structure and places it in a per-cpu subbuffer. 179 */ 180 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 181 int rw, u32 what, int error, int pdu_len, void *pdu_data) 182 { 183 struct task_struct *tsk = current; 184 struct ring_buffer_event *event = NULL; 185 struct ring_buffer *buffer = NULL; 186 struct blk_io_trace *t; 187 unsigned long flags = 0; 188 unsigned long *sequence; 189 pid_t pid; 190 int cpu, pc = 0; 191 bool blk_tracer = blk_tracer_enabled; 192 193 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 194 return; 195 196 what |= ddir_act[rw & WRITE]; 197 what |= MASK_TC_BIT(rw, BARRIER); 198 what |= MASK_TC_BIT(rw, SYNCIO); 199 what |= MASK_TC_BIT(rw, AHEAD); 200 what |= MASK_TC_BIT(rw, META); 201 what |= MASK_TC_BIT(rw, DISCARD); 202 203 pid = tsk->pid; 204 if (act_log_check(bt, what, sector, pid)) 205 return; 206 cpu = raw_smp_processor_id(); 207 208 if (blk_tracer) { 209 tracing_record_cmdline(current); 210 211 buffer = blk_tr->buffer; 212 pc = preempt_count(); 213 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 214 sizeof(*t) + pdu_len, 215 0, pc); 216 if (!event) 217 return; 218 t = ring_buffer_event_data(event); 219 goto record_it; 220 } 221 222 /* 223 * A word about the locking here - we disable interrupts to reserve 224 * some space in the relay per-cpu buffer, to prevent an irq 225 * from coming in and stepping on our toes. 226 */ 227 local_irq_save(flags); 228 229 if (unlikely(tsk->btrace_seq != blktrace_seq)) 230 trace_note_tsk(bt, tsk); 231 232 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 233 if (t) { 234 sequence = per_cpu_ptr(bt->sequence, cpu); 235 236 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 237 t->sequence = ++(*sequence); 238 t->time = ktime_to_ns(ktime_get()); 239 record_it: 240 /* 241 * These two are not needed in ftrace as they are in the 242 * generic trace_entry, filled by tracing_generic_entry_update, 243 * but for the trace_event->bin() synthesizer benefit we do it 244 * here too. 245 */ 246 t->cpu = cpu; 247 t->pid = pid; 248 249 t->sector = sector; 250 t->bytes = bytes; 251 t->action = what; 252 t->device = bt->dev; 253 t->error = error; 254 t->pdu_len = pdu_len; 255 256 if (pdu_len) 257 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 258 259 if (blk_tracer) { 260 trace_buffer_unlock_commit(buffer, event, 0, pc); 261 return; 262 } 263 } 264 265 local_irq_restore(flags); 266 } 267 268 static struct dentry *blk_tree_root; 269 static DEFINE_MUTEX(blk_tree_mutex); 270 271 static void blk_trace_free(struct blk_trace *bt) 272 { 273 debugfs_remove(bt->msg_file); 274 debugfs_remove(bt->dropped_file); 275 relay_close(bt->rchan); 276 debugfs_remove(bt->dir); 277 free_percpu(bt->sequence); 278 free_percpu(bt->msg_data); 279 kfree(bt); 280 } 281 282 static void blk_trace_cleanup(struct blk_trace *bt) 283 { 284 blk_trace_free(bt); 285 if (atomic_dec_and_test(&blk_probes_ref)) 286 blk_unregister_tracepoints(); 287 } 288 289 int blk_trace_remove(struct request_queue *q) 290 { 291 struct blk_trace *bt; 292 293 bt = xchg(&q->blk_trace, NULL); 294 if (!bt) 295 return -EINVAL; 296 297 if (bt->trace_state != Blktrace_running) 298 blk_trace_cleanup(bt); 299 300 return 0; 301 } 302 EXPORT_SYMBOL_GPL(blk_trace_remove); 303 304 static int blk_dropped_open(struct inode *inode, struct file *filp) 305 { 306 filp->private_data = inode->i_private; 307 308 return 0; 309 } 310 311 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 312 size_t count, loff_t *ppos) 313 { 314 struct blk_trace *bt = filp->private_data; 315 char buf[16]; 316 317 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 318 319 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 320 } 321 322 static const struct file_operations blk_dropped_fops = { 323 .owner = THIS_MODULE, 324 .open = blk_dropped_open, 325 .read = blk_dropped_read, 326 }; 327 328 static int blk_msg_open(struct inode *inode, struct file *filp) 329 { 330 filp->private_data = inode->i_private; 331 332 return 0; 333 } 334 335 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 336 size_t count, loff_t *ppos) 337 { 338 char *msg; 339 struct blk_trace *bt; 340 341 if (count >= BLK_TN_MAX_MSG) 342 return -EINVAL; 343 344 msg = kmalloc(count + 1, GFP_KERNEL); 345 if (msg == NULL) 346 return -ENOMEM; 347 348 if (copy_from_user(msg, buffer, count)) { 349 kfree(msg); 350 return -EFAULT; 351 } 352 353 msg[count] = '\0'; 354 bt = filp->private_data; 355 __trace_note_message(bt, "%s", msg); 356 kfree(msg); 357 358 return count; 359 } 360 361 static const struct file_operations blk_msg_fops = { 362 .owner = THIS_MODULE, 363 .open = blk_msg_open, 364 .write = blk_msg_write, 365 }; 366 367 /* 368 * Keep track of how many times we encountered a full subbuffer, to aid 369 * the user space app in telling how many lost events there were. 370 */ 371 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 372 void *prev_subbuf, size_t prev_padding) 373 { 374 struct blk_trace *bt; 375 376 if (!relay_buf_full(buf)) 377 return 1; 378 379 bt = buf->chan->private_data; 380 atomic_inc(&bt->dropped); 381 return 0; 382 } 383 384 static int blk_remove_buf_file_callback(struct dentry *dentry) 385 { 386 debugfs_remove(dentry); 387 388 return 0; 389 } 390 391 static struct dentry *blk_create_buf_file_callback(const char *filename, 392 struct dentry *parent, 393 int mode, 394 struct rchan_buf *buf, 395 int *is_global) 396 { 397 return debugfs_create_file(filename, mode, parent, buf, 398 &relay_file_operations); 399 } 400 401 static struct rchan_callbacks blk_relay_callbacks = { 402 .subbuf_start = blk_subbuf_start_callback, 403 .create_buf_file = blk_create_buf_file_callback, 404 .remove_buf_file = blk_remove_buf_file_callback, 405 }; 406 407 static void blk_trace_setup_lba(struct blk_trace *bt, 408 struct block_device *bdev) 409 { 410 struct hd_struct *part = NULL; 411 412 if (bdev) 413 part = bdev->bd_part; 414 415 if (part) { 416 bt->start_lba = part->start_sect; 417 bt->end_lba = part->start_sect + part->nr_sects; 418 } else { 419 bt->start_lba = 0; 420 bt->end_lba = -1ULL; 421 } 422 } 423 424 /* 425 * Setup everything required to start tracing 426 */ 427 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 428 struct block_device *bdev, 429 struct blk_user_trace_setup *buts) 430 { 431 struct blk_trace *old_bt, *bt = NULL; 432 struct dentry *dir = NULL; 433 int ret, i; 434 435 if (!buts->buf_size || !buts->buf_nr) 436 return -EINVAL; 437 438 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 439 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 440 441 /* 442 * some device names have larger paths - convert the slashes 443 * to underscores for this to work as expected 444 */ 445 for (i = 0; i < strlen(buts->name); i++) 446 if (buts->name[i] == '/') 447 buts->name[i] = '_'; 448 449 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 450 if (!bt) 451 return -ENOMEM; 452 453 ret = -ENOMEM; 454 bt->sequence = alloc_percpu(unsigned long); 455 if (!bt->sequence) 456 goto err; 457 458 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 459 if (!bt->msg_data) 460 goto err; 461 462 ret = -ENOENT; 463 464 mutex_lock(&blk_tree_mutex); 465 if (!blk_tree_root) { 466 blk_tree_root = debugfs_create_dir("block", NULL); 467 if (!blk_tree_root) { 468 mutex_unlock(&blk_tree_mutex); 469 goto err; 470 } 471 } 472 mutex_unlock(&blk_tree_mutex); 473 474 dir = debugfs_create_dir(buts->name, blk_tree_root); 475 476 if (!dir) 477 goto err; 478 479 bt->dir = dir; 480 bt->dev = dev; 481 atomic_set(&bt->dropped, 0); 482 483 ret = -EIO; 484 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 485 &blk_dropped_fops); 486 if (!bt->dropped_file) 487 goto err; 488 489 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 490 if (!bt->msg_file) 491 goto err; 492 493 bt->rchan = relay_open("trace", dir, buts->buf_size, 494 buts->buf_nr, &blk_relay_callbacks, bt); 495 if (!bt->rchan) 496 goto err; 497 498 bt->act_mask = buts->act_mask; 499 if (!bt->act_mask) 500 bt->act_mask = (u16) -1; 501 502 blk_trace_setup_lba(bt, bdev); 503 504 /* overwrite with user settings */ 505 if (buts->start_lba) 506 bt->start_lba = buts->start_lba; 507 if (buts->end_lba) 508 bt->end_lba = buts->end_lba; 509 510 bt->pid = buts->pid; 511 bt->trace_state = Blktrace_setup; 512 513 ret = -EBUSY; 514 old_bt = xchg(&q->blk_trace, bt); 515 if (old_bt) { 516 (void) xchg(&q->blk_trace, old_bt); 517 goto err; 518 } 519 520 if (atomic_inc_return(&blk_probes_ref) == 1) 521 blk_register_tracepoints(); 522 523 return 0; 524 err: 525 blk_trace_free(bt); 526 return ret; 527 } 528 529 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 530 struct block_device *bdev, 531 char __user *arg) 532 { 533 struct blk_user_trace_setup buts; 534 int ret; 535 536 ret = copy_from_user(&buts, arg, sizeof(buts)); 537 if (ret) 538 return -EFAULT; 539 540 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 541 if (ret) 542 return ret; 543 544 if (copy_to_user(arg, &buts, sizeof(buts))) { 545 blk_trace_remove(q); 546 return -EFAULT; 547 } 548 return 0; 549 } 550 EXPORT_SYMBOL_GPL(blk_trace_setup); 551 552 int blk_trace_startstop(struct request_queue *q, int start) 553 { 554 int ret; 555 struct blk_trace *bt = q->blk_trace; 556 557 if (bt == NULL) 558 return -EINVAL; 559 560 /* 561 * For starting a trace, we can transition from a setup or stopped 562 * trace. For stopping a trace, the state must be running 563 */ 564 ret = -EINVAL; 565 if (start) { 566 if (bt->trace_state == Blktrace_setup || 567 bt->trace_state == Blktrace_stopped) { 568 blktrace_seq++; 569 smp_mb(); 570 bt->trace_state = Blktrace_running; 571 572 trace_note_time(bt); 573 ret = 0; 574 } 575 } else { 576 if (bt->trace_state == Blktrace_running) { 577 bt->trace_state = Blktrace_stopped; 578 relay_flush(bt->rchan); 579 ret = 0; 580 } 581 } 582 583 return ret; 584 } 585 EXPORT_SYMBOL_GPL(blk_trace_startstop); 586 587 /** 588 * blk_trace_ioctl: - handle the ioctls associated with tracing 589 * @bdev: the block device 590 * @cmd: the ioctl cmd 591 * @arg: the argument data, if any 592 * 593 **/ 594 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 595 { 596 struct request_queue *q; 597 int ret, start = 0; 598 char b[BDEVNAME_SIZE]; 599 600 q = bdev_get_queue(bdev); 601 if (!q) 602 return -ENXIO; 603 604 mutex_lock(&bdev->bd_mutex); 605 606 switch (cmd) { 607 case BLKTRACESETUP: 608 bdevname(bdev, b); 609 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 610 break; 611 case BLKTRACESTART: 612 start = 1; 613 case BLKTRACESTOP: 614 ret = blk_trace_startstop(q, start); 615 break; 616 case BLKTRACETEARDOWN: 617 ret = blk_trace_remove(q); 618 break; 619 default: 620 ret = -ENOTTY; 621 break; 622 } 623 624 mutex_unlock(&bdev->bd_mutex); 625 return ret; 626 } 627 628 /** 629 * blk_trace_shutdown: - stop and cleanup trace structures 630 * @q: the request queue associated with the device 631 * 632 **/ 633 void blk_trace_shutdown(struct request_queue *q) 634 { 635 if (q->blk_trace) { 636 blk_trace_startstop(q, 0); 637 blk_trace_remove(q); 638 } 639 } 640 641 /* 642 * blktrace probes 643 */ 644 645 /** 646 * blk_add_trace_rq - Add a trace for a request oriented action 647 * @q: queue the io is for 648 * @rq: the source request 649 * @what: the action 650 * 651 * Description: 652 * Records an action against a request. Will log the bio offset + size. 653 * 654 **/ 655 static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 656 u32 what) 657 { 658 struct blk_trace *bt = q->blk_trace; 659 int rw = rq->cmd_flags & 0x03; 660 661 if (likely(!bt)) 662 return; 663 664 if (blk_discard_rq(rq)) 665 rw |= (1 << BIO_RW_DISCARD); 666 667 if (blk_pc_request(rq)) { 668 what |= BLK_TC_ACT(BLK_TC_PC); 669 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw, 670 what, rq->errors, rq->cmd_len, rq->cmd); 671 } else { 672 what |= BLK_TC_ACT(BLK_TC_FS); 673 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw, 674 what, rq->errors, 0, NULL); 675 } 676 } 677 678 static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq) 679 { 680 blk_add_trace_rq(q, rq, BLK_TA_ABORT); 681 } 682 683 static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq) 684 { 685 blk_add_trace_rq(q, rq, BLK_TA_INSERT); 686 } 687 688 static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq) 689 { 690 blk_add_trace_rq(q, rq, BLK_TA_ISSUE); 691 } 692 693 static void blk_add_trace_rq_requeue(struct request_queue *q, 694 struct request *rq) 695 { 696 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); 697 } 698 699 static void blk_add_trace_rq_complete(struct request_queue *q, 700 struct request *rq) 701 { 702 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE); 703 } 704 705 /** 706 * blk_add_trace_bio - Add a trace for a bio oriented action 707 * @q: queue the io is for 708 * @bio: the source bio 709 * @what: the action 710 * 711 * Description: 712 * Records an action against a bio. Will log the bio offset + size. 713 * 714 **/ 715 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 716 u32 what) 717 { 718 struct blk_trace *bt = q->blk_trace; 719 720 if (likely(!bt)) 721 return; 722 723 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, 724 !bio_flagged(bio, BIO_UPTODATE), 0, NULL); 725 } 726 727 static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio) 728 { 729 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE); 730 } 731 732 static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio) 733 { 734 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE); 735 } 736 737 static void blk_add_trace_bio_backmerge(struct request_queue *q, 738 struct bio *bio) 739 { 740 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE); 741 } 742 743 static void blk_add_trace_bio_frontmerge(struct request_queue *q, 744 struct bio *bio) 745 { 746 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE); 747 } 748 749 static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio) 750 { 751 blk_add_trace_bio(q, bio, BLK_TA_QUEUE); 752 } 753 754 static void blk_add_trace_getrq(struct request_queue *q, 755 struct bio *bio, int rw) 756 { 757 if (bio) 758 blk_add_trace_bio(q, bio, BLK_TA_GETRQ); 759 else { 760 struct blk_trace *bt = q->blk_trace; 761 762 if (bt) 763 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); 764 } 765 } 766 767 768 static void blk_add_trace_sleeprq(struct request_queue *q, 769 struct bio *bio, int rw) 770 { 771 if (bio) 772 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ); 773 else { 774 struct blk_trace *bt = q->blk_trace; 775 776 if (bt) 777 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 778 0, 0, NULL); 779 } 780 } 781 782 static void blk_add_trace_plug(struct request_queue *q) 783 { 784 struct blk_trace *bt = q->blk_trace; 785 786 if (bt) 787 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 788 } 789 790 static void blk_add_trace_unplug_io(struct request_queue *q) 791 { 792 struct blk_trace *bt = q->blk_trace; 793 794 if (bt) { 795 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 796 __be64 rpdu = cpu_to_be64(pdu); 797 798 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0, 799 sizeof(rpdu), &rpdu); 800 } 801 } 802 803 static void blk_add_trace_unplug_timer(struct request_queue *q) 804 { 805 struct blk_trace *bt = q->blk_trace; 806 807 if (bt) { 808 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 809 __be64 rpdu = cpu_to_be64(pdu); 810 811 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0, 812 sizeof(rpdu), &rpdu); 813 } 814 } 815 816 static void blk_add_trace_split(struct request_queue *q, struct bio *bio, 817 unsigned int pdu) 818 { 819 struct blk_trace *bt = q->blk_trace; 820 821 if (bt) { 822 __be64 rpdu = cpu_to_be64(pdu); 823 824 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 825 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE), 826 sizeof(rpdu), &rpdu); 827 } 828 } 829 830 /** 831 * blk_add_trace_remap - Add a trace for a remap operation 832 * @q: queue the io is for 833 * @bio: the source bio 834 * @dev: target device 835 * @from: source sector 836 * 837 * Description: 838 * Device mapper or raid target sometimes need to split a bio because 839 * it spans a stripe (or similar). Add a trace for that action. 840 * 841 **/ 842 static void blk_add_trace_remap(struct request_queue *q, struct bio *bio, 843 dev_t dev, sector_t from) 844 { 845 struct blk_trace *bt = q->blk_trace; 846 struct blk_io_trace_remap r; 847 848 if (likely(!bt)) 849 return; 850 851 r.device_from = cpu_to_be32(dev); 852 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 853 r.sector_from = cpu_to_be64(from); 854 855 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 856 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), 857 sizeof(r), &r); 858 } 859 860 /** 861 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 862 * @q: queue the io is for 863 * @rq: the source request 864 * @dev: target device 865 * @from: source sector 866 * 867 * Description: 868 * Device mapper remaps request to other devices. 869 * Add a trace for that action. 870 * 871 **/ 872 static void blk_add_trace_rq_remap(struct request_queue *q, 873 struct request *rq, dev_t dev, 874 sector_t from) 875 { 876 struct blk_trace *bt = q->blk_trace; 877 struct blk_io_trace_remap r; 878 879 if (likely(!bt)) 880 return; 881 882 r.device_from = cpu_to_be32(dev); 883 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 884 r.sector_from = cpu_to_be64(from); 885 886 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 887 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors, 888 sizeof(r), &r); 889 } 890 891 /** 892 * blk_add_driver_data - Add binary message with driver-specific data 893 * @q: queue the io is for 894 * @rq: io request 895 * @data: driver-specific data 896 * @len: length of driver-specific data 897 * 898 * Description: 899 * Some drivers might want to write driver-specific data per request. 900 * 901 **/ 902 void blk_add_driver_data(struct request_queue *q, 903 struct request *rq, 904 void *data, size_t len) 905 { 906 struct blk_trace *bt = q->blk_trace; 907 908 if (likely(!bt)) 909 return; 910 911 if (blk_pc_request(rq)) 912 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 913 BLK_TA_DRV_DATA, rq->errors, len, data); 914 else 915 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 916 BLK_TA_DRV_DATA, rq->errors, len, data); 917 } 918 EXPORT_SYMBOL_GPL(blk_add_driver_data); 919 920 static void blk_register_tracepoints(void) 921 { 922 int ret; 923 924 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort); 925 WARN_ON(ret); 926 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert); 927 WARN_ON(ret); 928 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue); 929 WARN_ON(ret); 930 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue); 931 WARN_ON(ret); 932 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete); 933 WARN_ON(ret); 934 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce); 935 WARN_ON(ret); 936 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete); 937 WARN_ON(ret); 938 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge); 939 WARN_ON(ret); 940 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge); 941 WARN_ON(ret); 942 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue); 943 WARN_ON(ret); 944 ret = register_trace_block_getrq(blk_add_trace_getrq); 945 WARN_ON(ret); 946 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq); 947 WARN_ON(ret); 948 ret = register_trace_block_plug(blk_add_trace_plug); 949 WARN_ON(ret); 950 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer); 951 WARN_ON(ret); 952 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io); 953 WARN_ON(ret); 954 ret = register_trace_block_split(blk_add_trace_split); 955 WARN_ON(ret); 956 ret = register_trace_block_remap(blk_add_trace_remap); 957 WARN_ON(ret); 958 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap); 959 WARN_ON(ret); 960 } 961 962 static void blk_unregister_tracepoints(void) 963 { 964 unregister_trace_block_rq_remap(blk_add_trace_rq_remap); 965 unregister_trace_block_remap(blk_add_trace_remap); 966 unregister_trace_block_split(blk_add_trace_split); 967 unregister_trace_block_unplug_io(blk_add_trace_unplug_io); 968 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer); 969 unregister_trace_block_plug(blk_add_trace_plug); 970 unregister_trace_block_sleeprq(blk_add_trace_sleeprq); 971 unregister_trace_block_getrq(blk_add_trace_getrq); 972 unregister_trace_block_bio_queue(blk_add_trace_bio_queue); 973 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge); 974 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge); 975 unregister_trace_block_bio_complete(blk_add_trace_bio_complete); 976 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce); 977 unregister_trace_block_rq_complete(blk_add_trace_rq_complete); 978 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue); 979 unregister_trace_block_rq_issue(blk_add_trace_rq_issue); 980 unregister_trace_block_rq_insert(blk_add_trace_rq_insert); 981 unregister_trace_block_rq_abort(blk_add_trace_rq_abort); 982 983 tracepoint_synchronize_unregister(); 984 } 985 986 /* 987 * struct blk_io_tracer formatting routines 988 */ 989 990 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 991 { 992 int i = 0; 993 int tc = t->action >> BLK_TC_SHIFT; 994 995 if (t->action == BLK_TN_MESSAGE) { 996 rwbs[i++] = 'N'; 997 goto out; 998 } 999 1000 if (tc & BLK_TC_DISCARD) 1001 rwbs[i++] = 'D'; 1002 else if (tc & BLK_TC_WRITE) 1003 rwbs[i++] = 'W'; 1004 else if (t->bytes) 1005 rwbs[i++] = 'R'; 1006 else 1007 rwbs[i++] = 'N'; 1008 1009 if (tc & BLK_TC_AHEAD) 1010 rwbs[i++] = 'A'; 1011 if (tc & BLK_TC_BARRIER) 1012 rwbs[i++] = 'B'; 1013 if (tc & BLK_TC_SYNC) 1014 rwbs[i++] = 'S'; 1015 if (tc & BLK_TC_META) 1016 rwbs[i++] = 'M'; 1017 out: 1018 rwbs[i] = '\0'; 1019 } 1020 1021 static inline 1022 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1023 { 1024 return (const struct blk_io_trace *)ent; 1025 } 1026 1027 static inline const void *pdu_start(const struct trace_entry *ent) 1028 { 1029 return te_blk_io_trace(ent) + 1; 1030 } 1031 1032 static inline u32 t_action(const struct trace_entry *ent) 1033 { 1034 return te_blk_io_trace(ent)->action; 1035 } 1036 1037 static inline u32 t_bytes(const struct trace_entry *ent) 1038 { 1039 return te_blk_io_trace(ent)->bytes; 1040 } 1041 1042 static inline u32 t_sec(const struct trace_entry *ent) 1043 { 1044 return te_blk_io_trace(ent)->bytes >> 9; 1045 } 1046 1047 static inline unsigned long long t_sector(const struct trace_entry *ent) 1048 { 1049 return te_blk_io_trace(ent)->sector; 1050 } 1051 1052 static inline __u16 t_error(const struct trace_entry *ent) 1053 { 1054 return te_blk_io_trace(ent)->error; 1055 } 1056 1057 static __u64 get_pdu_int(const struct trace_entry *ent) 1058 { 1059 const __u64 *val = pdu_start(ent); 1060 return be64_to_cpu(*val); 1061 } 1062 1063 static void get_pdu_remap(const struct trace_entry *ent, 1064 struct blk_io_trace_remap *r) 1065 { 1066 const struct blk_io_trace_remap *__r = pdu_start(ent); 1067 __u64 sector_from = __r->sector_from; 1068 1069 r->device_from = be32_to_cpu(__r->device_from); 1070 r->device_to = be32_to_cpu(__r->device_to); 1071 r->sector_from = be64_to_cpu(sector_from); 1072 } 1073 1074 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1075 1076 static int blk_log_action_classic(struct trace_iterator *iter, const char *act) 1077 { 1078 char rwbs[6]; 1079 unsigned long long ts = iter->ts; 1080 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1081 unsigned secs = (unsigned long)ts; 1082 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1083 1084 fill_rwbs(rwbs, t); 1085 1086 return trace_seq_printf(&iter->seq, 1087 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1088 MAJOR(t->device), MINOR(t->device), iter->cpu, 1089 secs, nsec_rem, iter->ent->pid, act, rwbs); 1090 } 1091 1092 static int blk_log_action(struct trace_iterator *iter, const char *act) 1093 { 1094 char rwbs[6]; 1095 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1096 1097 fill_rwbs(rwbs, t); 1098 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1099 MAJOR(t->device), MINOR(t->device), act, rwbs); 1100 } 1101 1102 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1103 { 1104 const unsigned char *pdu_buf; 1105 int pdu_len; 1106 int i, end, ret; 1107 1108 pdu_buf = pdu_start(ent); 1109 pdu_len = te_blk_io_trace(ent)->pdu_len; 1110 1111 if (!pdu_len) 1112 return 1; 1113 1114 /* find the last zero that needs to be printed */ 1115 for (end = pdu_len - 1; end >= 0; end--) 1116 if (pdu_buf[end]) 1117 break; 1118 end++; 1119 1120 if (!trace_seq_putc(s, '(')) 1121 return 0; 1122 1123 for (i = 0; i < pdu_len; i++) { 1124 1125 ret = trace_seq_printf(s, "%s%02x", 1126 i == 0 ? "" : " ", pdu_buf[i]); 1127 if (!ret) 1128 return ret; 1129 1130 /* 1131 * stop when the rest is just zeroes and indicate so 1132 * with a ".." appended 1133 */ 1134 if (i == end && end != pdu_len - 1) 1135 return trace_seq_puts(s, " ..) "); 1136 } 1137 1138 return trace_seq_puts(s, ") "); 1139 } 1140 1141 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1142 { 1143 char cmd[TASK_COMM_LEN]; 1144 1145 trace_find_cmdline(ent->pid, cmd); 1146 1147 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1148 int ret; 1149 1150 ret = trace_seq_printf(s, "%u ", t_bytes(ent)); 1151 if (!ret) 1152 return 0; 1153 ret = blk_log_dump_pdu(s, ent); 1154 if (!ret) 1155 return 0; 1156 return trace_seq_printf(s, "[%s]\n", cmd); 1157 } else { 1158 if (t_sec(ent)) 1159 return trace_seq_printf(s, "%llu + %u [%s]\n", 1160 t_sector(ent), t_sec(ent), cmd); 1161 return trace_seq_printf(s, "[%s]\n", cmd); 1162 } 1163 } 1164 1165 static int blk_log_with_error(struct trace_seq *s, 1166 const struct trace_entry *ent) 1167 { 1168 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1169 int ret; 1170 1171 ret = blk_log_dump_pdu(s, ent); 1172 if (ret) 1173 return trace_seq_printf(s, "[%d]\n", t_error(ent)); 1174 return 0; 1175 } else { 1176 if (t_sec(ent)) 1177 return trace_seq_printf(s, "%llu + %u [%d]\n", 1178 t_sector(ent), 1179 t_sec(ent), t_error(ent)); 1180 return trace_seq_printf(s, "%llu [%d]\n", 1181 t_sector(ent), t_error(ent)); 1182 } 1183 } 1184 1185 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1186 { 1187 struct blk_io_trace_remap r = { .device_from = 0, }; 1188 1189 get_pdu_remap(ent, &r); 1190 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1191 t_sector(ent), t_sec(ent), 1192 MAJOR(r.device_from), MINOR(r.device_from), 1193 (unsigned long long)r.sector_from); 1194 } 1195 1196 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1197 { 1198 char cmd[TASK_COMM_LEN]; 1199 1200 trace_find_cmdline(ent->pid, cmd); 1201 1202 return trace_seq_printf(s, "[%s]\n", cmd); 1203 } 1204 1205 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1206 { 1207 char cmd[TASK_COMM_LEN]; 1208 1209 trace_find_cmdline(ent->pid, cmd); 1210 1211 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1212 } 1213 1214 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1215 { 1216 char cmd[TASK_COMM_LEN]; 1217 1218 trace_find_cmdline(ent->pid, cmd); 1219 1220 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1221 get_pdu_int(ent), cmd); 1222 } 1223 1224 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1225 { 1226 int ret; 1227 const struct blk_io_trace *t = te_blk_io_trace(ent); 1228 1229 ret = trace_seq_putmem(s, t + 1, t->pdu_len); 1230 if (ret) 1231 return trace_seq_putc(s, '\n'); 1232 return ret; 1233 } 1234 1235 /* 1236 * struct tracer operations 1237 */ 1238 1239 static void blk_tracer_print_header(struct seq_file *m) 1240 { 1241 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1242 return; 1243 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1244 "# | | | | | |\n"); 1245 } 1246 1247 static void blk_tracer_start(struct trace_array *tr) 1248 { 1249 blk_tracer_enabled = true; 1250 } 1251 1252 static int blk_tracer_init(struct trace_array *tr) 1253 { 1254 blk_tr = tr; 1255 blk_tracer_start(tr); 1256 return 0; 1257 } 1258 1259 static void blk_tracer_stop(struct trace_array *tr) 1260 { 1261 blk_tracer_enabled = false; 1262 } 1263 1264 static void blk_tracer_reset(struct trace_array *tr) 1265 { 1266 blk_tracer_stop(tr); 1267 } 1268 1269 static const struct { 1270 const char *act[2]; 1271 int (*print)(struct trace_seq *s, const struct trace_entry *ent); 1272 } what2act[] = { 1273 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1274 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1275 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1276 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1277 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1278 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1279 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1280 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1281 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1282 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1283 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1284 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1285 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1286 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1287 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1288 }; 1289 1290 static enum print_line_t print_one_line(struct trace_iterator *iter, 1291 bool classic) 1292 { 1293 struct trace_seq *s = &iter->seq; 1294 const struct blk_io_trace *t; 1295 u16 what; 1296 int ret; 1297 bool long_act; 1298 blk_log_action_t *log_action; 1299 1300 t = te_blk_io_trace(iter->ent); 1301 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1302 long_act = !!(trace_flags & TRACE_ITER_VERBOSE); 1303 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1304 1305 if (t->action == BLK_TN_MESSAGE) { 1306 ret = log_action(iter, long_act ? "message" : "m"); 1307 if (ret) 1308 ret = blk_log_msg(s, iter->ent); 1309 goto out; 1310 } 1311 1312 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1313 ret = trace_seq_printf(s, "Unknown action %x\n", what); 1314 else { 1315 ret = log_action(iter, what2act[what].act[long_act]); 1316 if (ret) 1317 ret = what2act[what].print(s, iter->ent); 1318 } 1319 out: 1320 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1321 } 1322 1323 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1324 int flags) 1325 { 1326 return print_one_line(iter, false); 1327 } 1328 1329 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1330 { 1331 struct trace_seq *s = &iter->seq; 1332 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1333 const int offset = offsetof(struct blk_io_trace, sector); 1334 struct blk_io_trace old = { 1335 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1336 .time = iter->ts, 1337 }; 1338 1339 if (!trace_seq_putmem(s, &old, offset)) 1340 return 0; 1341 return trace_seq_putmem(s, &t->sector, 1342 sizeof(old) - offset + t->pdu_len); 1343 } 1344 1345 static enum print_line_t 1346 blk_trace_event_print_binary(struct trace_iterator *iter, int flags) 1347 { 1348 return blk_trace_synthesize_old_trace(iter) ? 1349 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1350 } 1351 1352 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1353 { 1354 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1355 return TRACE_TYPE_UNHANDLED; 1356 1357 return print_one_line(iter, true); 1358 } 1359 1360 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set) 1361 { 1362 /* don't output context-info for blk_classic output */ 1363 if (bit == TRACE_BLK_OPT_CLASSIC) { 1364 if (set) 1365 trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1366 else 1367 trace_flags |= TRACE_ITER_CONTEXT_INFO; 1368 } 1369 return 0; 1370 } 1371 1372 static struct tracer blk_tracer __read_mostly = { 1373 .name = "blk", 1374 .init = blk_tracer_init, 1375 .reset = blk_tracer_reset, 1376 .start = blk_tracer_start, 1377 .stop = blk_tracer_stop, 1378 .print_header = blk_tracer_print_header, 1379 .print_line = blk_tracer_print_line, 1380 .flags = &blk_tracer_flags, 1381 .set_flag = blk_tracer_set_flag, 1382 }; 1383 1384 static struct trace_event trace_blk_event = { 1385 .type = TRACE_BLK, 1386 .trace = blk_trace_event_print, 1387 .binary = blk_trace_event_print_binary, 1388 }; 1389 1390 static int __init init_blk_tracer(void) 1391 { 1392 if (!register_ftrace_event(&trace_blk_event)) { 1393 pr_warning("Warning: could not register block events\n"); 1394 return 1; 1395 } 1396 1397 if (register_tracer(&blk_tracer) != 0) { 1398 pr_warning("Warning: could not register the block tracer\n"); 1399 unregister_ftrace_event(&trace_blk_event); 1400 return 1; 1401 } 1402 1403 return 0; 1404 } 1405 1406 device_initcall(init_blk_tracer); 1407 1408 static int blk_trace_remove_queue(struct request_queue *q) 1409 { 1410 struct blk_trace *bt; 1411 1412 bt = xchg(&q->blk_trace, NULL); 1413 if (bt == NULL) 1414 return -EINVAL; 1415 1416 if (atomic_dec_and_test(&blk_probes_ref)) 1417 blk_unregister_tracepoints(); 1418 1419 blk_trace_free(bt); 1420 return 0; 1421 } 1422 1423 /* 1424 * Setup everything required to start tracing 1425 */ 1426 static int blk_trace_setup_queue(struct request_queue *q, 1427 struct block_device *bdev) 1428 { 1429 struct blk_trace *old_bt, *bt = NULL; 1430 int ret = -ENOMEM; 1431 1432 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1433 if (!bt) 1434 return -ENOMEM; 1435 1436 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1437 if (!bt->msg_data) 1438 goto free_bt; 1439 1440 bt->dev = bdev->bd_dev; 1441 bt->act_mask = (u16)-1; 1442 1443 blk_trace_setup_lba(bt, bdev); 1444 1445 old_bt = xchg(&q->blk_trace, bt); 1446 if (old_bt != NULL) { 1447 (void)xchg(&q->blk_trace, old_bt); 1448 ret = -EBUSY; 1449 goto free_bt; 1450 } 1451 1452 if (atomic_inc_return(&blk_probes_ref) == 1) 1453 blk_register_tracepoints(); 1454 return 0; 1455 1456 free_bt: 1457 blk_trace_free(bt); 1458 return ret; 1459 } 1460 1461 /* 1462 * sysfs interface to enable and configure tracing 1463 */ 1464 1465 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1466 struct device_attribute *attr, 1467 char *buf); 1468 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1469 struct device_attribute *attr, 1470 const char *buf, size_t count); 1471 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1472 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1473 sysfs_blk_trace_attr_show, \ 1474 sysfs_blk_trace_attr_store) 1475 1476 static BLK_TRACE_DEVICE_ATTR(enable); 1477 static BLK_TRACE_DEVICE_ATTR(act_mask); 1478 static BLK_TRACE_DEVICE_ATTR(pid); 1479 static BLK_TRACE_DEVICE_ATTR(start_lba); 1480 static BLK_TRACE_DEVICE_ATTR(end_lba); 1481 1482 static struct attribute *blk_trace_attrs[] = { 1483 &dev_attr_enable.attr, 1484 &dev_attr_act_mask.attr, 1485 &dev_attr_pid.attr, 1486 &dev_attr_start_lba.attr, 1487 &dev_attr_end_lba.attr, 1488 NULL 1489 }; 1490 1491 struct attribute_group blk_trace_attr_group = { 1492 .name = "trace", 1493 .attrs = blk_trace_attrs, 1494 }; 1495 1496 static const struct { 1497 int mask; 1498 const char *str; 1499 } mask_maps[] = { 1500 { BLK_TC_READ, "read" }, 1501 { BLK_TC_WRITE, "write" }, 1502 { BLK_TC_BARRIER, "barrier" }, 1503 { BLK_TC_SYNC, "sync" }, 1504 { BLK_TC_QUEUE, "queue" }, 1505 { BLK_TC_REQUEUE, "requeue" }, 1506 { BLK_TC_ISSUE, "issue" }, 1507 { BLK_TC_COMPLETE, "complete" }, 1508 { BLK_TC_FS, "fs" }, 1509 { BLK_TC_PC, "pc" }, 1510 { BLK_TC_AHEAD, "ahead" }, 1511 { BLK_TC_META, "meta" }, 1512 { BLK_TC_DISCARD, "discard" }, 1513 { BLK_TC_DRV_DATA, "drv_data" }, 1514 }; 1515 1516 static int blk_trace_str2mask(const char *str) 1517 { 1518 int i; 1519 int mask = 0; 1520 char *buf, *s, *token; 1521 1522 buf = kstrdup(str, GFP_KERNEL); 1523 if (buf == NULL) 1524 return -ENOMEM; 1525 s = strstrip(buf); 1526 1527 while (1) { 1528 token = strsep(&s, ","); 1529 if (token == NULL) 1530 break; 1531 1532 if (*token == '\0') 1533 continue; 1534 1535 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1536 if (strcasecmp(token, mask_maps[i].str) == 0) { 1537 mask |= mask_maps[i].mask; 1538 break; 1539 } 1540 } 1541 if (i == ARRAY_SIZE(mask_maps)) { 1542 mask = -EINVAL; 1543 break; 1544 } 1545 } 1546 kfree(buf); 1547 1548 return mask; 1549 } 1550 1551 static ssize_t blk_trace_mask2str(char *buf, int mask) 1552 { 1553 int i; 1554 char *p = buf; 1555 1556 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1557 if (mask & mask_maps[i].mask) { 1558 p += sprintf(p, "%s%s", 1559 (p == buf) ? "" : ",", mask_maps[i].str); 1560 } 1561 } 1562 *p++ = '\n'; 1563 1564 return p - buf; 1565 } 1566 1567 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1568 { 1569 if (bdev->bd_disk == NULL) 1570 return NULL; 1571 1572 return bdev_get_queue(bdev); 1573 } 1574 1575 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1576 struct device_attribute *attr, 1577 char *buf) 1578 { 1579 struct hd_struct *p = dev_to_part(dev); 1580 struct request_queue *q; 1581 struct block_device *bdev; 1582 ssize_t ret = -ENXIO; 1583 1584 lock_kernel(); 1585 bdev = bdget(part_devt(p)); 1586 if (bdev == NULL) 1587 goto out_unlock_kernel; 1588 1589 q = blk_trace_get_queue(bdev); 1590 if (q == NULL) 1591 goto out_bdput; 1592 1593 mutex_lock(&bdev->bd_mutex); 1594 1595 if (attr == &dev_attr_enable) { 1596 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1597 goto out_unlock_bdev; 1598 } 1599 1600 if (q->blk_trace == NULL) 1601 ret = sprintf(buf, "disabled\n"); 1602 else if (attr == &dev_attr_act_mask) 1603 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1604 else if (attr == &dev_attr_pid) 1605 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1606 else if (attr == &dev_attr_start_lba) 1607 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1608 else if (attr == &dev_attr_end_lba) 1609 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1610 1611 out_unlock_bdev: 1612 mutex_unlock(&bdev->bd_mutex); 1613 out_bdput: 1614 bdput(bdev); 1615 out_unlock_kernel: 1616 unlock_kernel(); 1617 return ret; 1618 } 1619 1620 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1621 struct device_attribute *attr, 1622 const char *buf, size_t count) 1623 { 1624 struct block_device *bdev; 1625 struct request_queue *q; 1626 struct hd_struct *p; 1627 u64 value; 1628 ssize_t ret = -EINVAL; 1629 1630 if (count == 0) 1631 goto out; 1632 1633 if (attr == &dev_attr_act_mask) { 1634 if (sscanf(buf, "%llx", &value) != 1) { 1635 /* Assume it is a list of trace category names */ 1636 ret = blk_trace_str2mask(buf); 1637 if (ret < 0) 1638 goto out; 1639 value = ret; 1640 } 1641 } else if (sscanf(buf, "%llu", &value) != 1) 1642 goto out; 1643 1644 ret = -ENXIO; 1645 1646 lock_kernel(); 1647 p = dev_to_part(dev); 1648 bdev = bdget(part_devt(p)); 1649 if (bdev == NULL) 1650 goto out_unlock_kernel; 1651 1652 q = blk_trace_get_queue(bdev); 1653 if (q == NULL) 1654 goto out_bdput; 1655 1656 mutex_lock(&bdev->bd_mutex); 1657 1658 if (attr == &dev_attr_enable) { 1659 if (value) 1660 ret = blk_trace_setup_queue(q, bdev); 1661 else 1662 ret = blk_trace_remove_queue(q); 1663 goto out_unlock_bdev; 1664 } 1665 1666 ret = 0; 1667 if (q->blk_trace == NULL) 1668 ret = blk_trace_setup_queue(q, bdev); 1669 1670 if (ret == 0) { 1671 if (attr == &dev_attr_act_mask) 1672 q->blk_trace->act_mask = value; 1673 else if (attr == &dev_attr_pid) 1674 q->blk_trace->pid = value; 1675 else if (attr == &dev_attr_start_lba) 1676 q->blk_trace->start_lba = value; 1677 else if (attr == &dev_attr_end_lba) 1678 q->blk_trace->end_lba = value; 1679 } 1680 1681 out_unlock_bdev: 1682 mutex_unlock(&bdev->bd_mutex); 1683 out_bdput: 1684 bdput(bdev); 1685 out_unlock_kernel: 1686 unlock_kernel(); 1687 out: 1688 return ret ? ret : count; 1689 } 1690 1691 int blk_trace_init_sysfs(struct device *dev) 1692 { 1693 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1694 } 1695 1696 void blk_trace_remove_sysfs(struct device *dev) 1697 { 1698 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1699 } 1700 1701 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1702 1703 #ifdef CONFIG_EVENT_TRACING 1704 1705 void blk_dump_cmd(char *buf, struct request *rq) 1706 { 1707 int i, end; 1708 int len = rq->cmd_len; 1709 unsigned char *cmd = rq->cmd; 1710 1711 if (!blk_pc_request(rq)) { 1712 buf[0] = '\0'; 1713 return; 1714 } 1715 1716 for (end = len - 1; end >= 0; end--) 1717 if (cmd[end]) 1718 break; 1719 end++; 1720 1721 for (i = 0; i < len; i++) { 1722 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1723 if (i == end && end != len - 1) { 1724 sprintf(buf, " .."); 1725 break; 1726 } 1727 } 1728 } 1729 1730 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) 1731 { 1732 int i = 0; 1733 1734 if (rw & WRITE) 1735 rwbs[i++] = 'W'; 1736 else if (rw & 1 << BIO_RW_DISCARD) 1737 rwbs[i++] = 'D'; 1738 else if (bytes) 1739 rwbs[i++] = 'R'; 1740 else 1741 rwbs[i++] = 'N'; 1742 1743 if (rw & 1 << BIO_RW_AHEAD) 1744 rwbs[i++] = 'A'; 1745 if (rw & 1 << BIO_RW_BARRIER) 1746 rwbs[i++] = 'B'; 1747 if (rw & 1 << BIO_RW_SYNCIO) 1748 rwbs[i++] = 'S'; 1749 if (rw & 1 << BIO_RW_META) 1750 rwbs[i++] = 'M'; 1751 1752 rwbs[i] = '\0'; 1753 } 1754 1755 void blk_fill_rwbs_rq(char *rwbs, struct request *rq) 1756 { 1757 int rw = rq->cmd_flags & 0x03; 1758 int bytes; 1759 1760 if (blk_discard_rq(rq)) 1761 rw |= (1 << BIO_RW_DISCARD); 1762 1763 bytes = blk_rq_bytes(rq); 1764 1765 blk_fill_rwbs(rwbs, rw, bytes); 1766 } 1767 1768 #endif /* CONFIG_EVENT_TRACING */ 1769 1770