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(void *ignore, 679 struct request_queue *q, struct request *rq) 680 { 681 blk_add_trace_rq(q, rq, BLK_TA_ABORT); 682 } 683 684 static void blk_add_trace_rq_insert(void *ignore, 685 struct request_queue *q, struct request *rq) 686 { 687 blk_add_trace_rq(q, rq, BLK_TA_INSERT); 688 } 689 690 static void blk_add_trace_rq_issue(void *ignore, 691 struct request_queue *q, struct request *rq) 692 { 693 blk_add_trace_rq(q, rq, BLK_TA_ISSUE); 694 } 695 696 static void blk_add_trace_rq_requeue(void *ignore, 697 struct request_queue *q, 698 struct request *rq) 699 { 700 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); 701 } 702 703 static void blk_add_trace_rq_complete(void *ignore, 704 struct request_queue *q, 705 struct request *rq) 706 { 707 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE); 708 } 709 710 /** 711 * blk_add_trace_bio - Add a trace for a bio oriented action 712 * @q: queue the io is for 713 * @bio: the source bio 714 * @what: the action 715 * 716 * Description: 717 * Records an action against a bio. Will log the bio offset + size. 718 * 719 **/ 720 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 721 u32 what) 722 { 723 struct blk_trace *bt = q->blk_trace; 724 725 if (likely(!bt)) 726 return; 727 728 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, 729 !bio_flagged(bio, BIO_UPTODATE), 0, NULL); 730 } 731 732 static void blk_add_trace_bio_bounce(void *ignore, 733 struct request_queue *q, struct bio *bio) 734 { 735 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE); 736 } 737 738 static void blk_add_trace_bio_complete(void *ignore, 739 struct request_queue *q, struct bio *bio) 740 { 741 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE); 742 } 743 744 static void blk_add_trace_bio_backmerge(void *ignore, 745 struct request_queue *q, 746 struct bio *bio) 747 { 748 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE); 749 } 750 751 static void blk_add_trace_bio_frontmerge(void *ignore, 752 struct request_queue *q, 753 struct bio *bio) 754 { 755 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE); 756 } 757 758 static void blk_add_trace_bio_queue(void *ignore, 759 struct request_queue *q, struct bio *bio) 760 { 761 blk_add_trace_bio(q, bio, BLK_TA_QUEUE); 762 } 763 764 static void blk_add_trace_getrq(void *ignore, 765 struct request_queue *q, 766 struct bio *bio, int rw) 767 { 768 if (bio) 769 blk_add_trace_bio(q, bio, BLK_TA_GETRQ); 770 else { 771 struct blk_trace *bt = q->blk_trace; 772 773 if (bt) 774 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); 775 } 776 } 777 778 779 static void blk_add_trace_sleeprq(void *ignore, 780 struct request_queue *q, 781 struct bio *bio, int rw) 782 { 783 if (bio) 784 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ); 785 else { 786 struct blk_trace *bt = q->blk_trace; 787 788 if (bt) 789 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 790 0, 0, NULL); 791 } 792 } 793 794 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 795 { 796 struct blk_trace *bt = q->blk_trace; 797 798 if (bt) 799 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 800 } 801 802 static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q) 803 { 804 struct blk_trace *bt = q->blk_trace; 805 806 if (bt) { 807 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 808 __be64 rpdu = cpu_to_be64(pdu); 809 810 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0, 811 sizeof(rpdu), &rpdu); 812 } 813 } 814 815 static void blk_add_trace_unplug_timer(void *ignore, struct request_queue *q) 816 { 817 struct blk_trace *bt = q->blk_trace; 818 819 if (bt) { 820 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 821 __be64 rpdu = cpu_to_be64(pdu); 822 823 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0, 824 sizeof(rpdu), &rpdu); 825 } 826 } 827 828 static void blk_add_trace_split(void *ignore, 829 struct request_queue *q, struct bio *bio, 830 unsigned int pdu) 831 { 832 struct blk_trace *bt = q->blk_trace; 833 834 if (bt) { 835 __be64 rpdu = cpu_to_be64(pdu); 836 837 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 838 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE), 839 sizeof(rpdu), &rpdu); 840 } 841 } 842 843 /** 844 * blk_add_trace_remap - Add a trace for a remap operation 845 * @q: queue the io is for 846 * @bio: the source bio 847 * @dev: target device 848 * @from: source sector 849 * 850 * Description: 851 * Device mapper or raid target sometimes need to split a bio because 852 * it spans a stripe (or similar). Add a trace for that action. 853 * 854 **/ 855 static void blk_add_trace_remap(void *ignore, 856 struct request_queue *q, struct bio *bio, 857 dev_t dev, sector_t from) 858 { 859 struct blk_trace *bt = q->blk_trace; 860 struct blk_io_trace_remap r; 861 862 if (likely(!bt)) 863 return; 864 865 r.device_from = cpu_to_be32(dev); 866 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 867 r.sector_from = cpu_to_be64(from); 868 869 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 870 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), 871 sizeof(r), &r); 872 } 873 874 /** 875 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 876 * @q: queue the io is for 877 * @rq: the source request 878 * @dev: target device 879 * @from: source sector 880 * 881 * Description: 882 * Device mapper remaps request to other devices. 883 * Add a trace for that action. 884 * 885 **/ 886 static void blk_add_trace_rq_remap(void *ignore, 887 struct request_queue *q, 888 struct request *rq, dev_t dev, 889 sector_t from) 890 { 891 struct blk_trace *bt = q->blk_trace; 892 struct blk_io_trace_remap r; 893 894 if (likely(!bt)) 895 return; 896 897 r.device_from = cpu_to_be32(dev); 898 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 899 r.sector_from = cpu_to_be64(from); 900 901 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 902 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors, 903 sizeof(r), &r); 904 } 905 906 /** 907 * blk_add_driver_data - Add binary message with driver-specific data 908 * @q: queue the io is for 909 * @rq: io request 910 * @data: driver-specific data 911 * @len: length of driver-specific data 912 * 913 * Description: 914 * Some drivers might want to write driver-specific data per request. 915 * 916 **/ 917 void blk_add_driver_data(struct request_queue *q, 918 struct request *rq, 919 void *data, size_t len) 920 { 921 struct blk_trace *bt = q->blk_trace; 922 923 if (likely(!bt)) 924 return; 925 926 if (blk_pc_request(rq)) 927 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 928 BLK_TA_DRV_DATA, rq->errors, len, data); 929 else 930 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 931 BLK_TA_DRV_DATA, rq->errors, len, data); 932 } 933 EXPORT_SYMBOL_GPL(blk_add_driver_data); 934 935 static void blk_register_tracepoints(void) 936 { 937 int ret; 938 939 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 940 WARN_ON(ret); 941 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 942 WARN_ON(ret); 943 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 944 WARN_ON(ret); 945 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 946 WARN_ON(ret); 947 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 948 WARN_ON(ret); 949 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 950 WARN_ON(ret); 951 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 952 WARN_ON(ret); 953 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 954 WARN_ON(ret); 955 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 956 WARN_ON(ret); 957 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 958 WARN_ON(ret); 959 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 960 WARN_ON(ret); 961 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 962 WARN_ON(ret); 963 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 964 WARN_ON(ret); 965 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL); 966 WARN_ON(ret); 967 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); 968 WARN_ON(ret); 969 ret = register_trace_block_split(blk_add_trace_split, NULL); 970 WARN_ON(ret); 971 ret = register_trace_block_remap(blk_add_trace_remap, NULL); 972 WARN_ON(ret); 973 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 974 WARN_ON(ret); 975 } 976 977 static void blk_unregister_tracepoints(void) 978 { 979 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 980 unregister_trace_block_remap(blk_add_trace_remap, NULL); 981 unregister_trace_block_split(blk_add_trace_split, NULL); 982 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); 983 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL); 984 unregister_trace_block_plug(blk_add_trace_plug, NULL); 985 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 986 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 987 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 988 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 989 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 990 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 991 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 992 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 993 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 994 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 995 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 996 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 997 998 tracepoint_synchronize_unregister(); 999 } 1000 1001 /* 1002 * struct blk_io_tracer formatting routines 1003 */ 1004 1005 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1006 { 1007 int i = 0; 1008 int tc = t->action >> BLK_TC_SHIFT; 1009 1010 if (t->action == BLK_TN_MESSAGE) { 1011 rwbs[i++] = 'N'; 1012 goto out; 1013 } 1014 1015 if (tc & BLK_TC_DISCARD) 1016 rwbs[i++] = 'D'; 1017 else if (tc & BLK_TC_WRITE) 1018 rwbs[i++] = 'W'; 1019 else if (t->bytes) 1020 rwbs[i++] = 'R'; 1021 else 1022 rwbs[i++] = 'N'; 1023 1024 if (tc & BLK_TC_AHEAD) 1025 rwbs[i++] = 'A'; 1026 if (tc & BLK_TC_BARRIER) 1027 rwbs[i++] = 'B'; 1028 if (tc & BLK_TC_SYNC) 1029 rwbs[i++] = 'S'; 1030 if (tc & BLK_TC_META) 1031 rwbs[i++] = 'M'; 1032 out: 1033 rwbs[i] = '\0'; 1034 } 1035 1036 static inline 1037 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1038 { 1039 return (const struct blk_io_trace *)ent; 1040 } 1041 1042 static inline const void *pdu_start(const struct trace_entry *ent) 1043 { 1044 return te_blk_io_trace(ent) + 1; 1045 } 1046 1047 static inline u32 t_action(const struct trace_entry *ent) 1048 { 1049 return te_blk_io_trace(ent)->action; 1050 } 1051 1052 static inline u32 t_bytes(const struct trace_entry *ent) 1053 { 1054 return te_blk_io_trace(ent)->bytes; 1055 } 1056 1057 static inline u32 t_sec(const struct trace_entry *ent) 1058 { 1059 return te_blk_io_trace(ent)->bytes >> 9; 1060 } 1061 1062 static inline unsigned long long t_sector(const struct trace_entry *ent) 1063 { 1064 return te_blk_io_trace(ent)->sector; 1065 } 1066 1067 static inline __u16 t_error(const struct trace_entry *ent) 1068 { 1069 return te_blk_io_trace(ent)->error; 1070 } 1071 1072 static __u64 get_pdu_int(const struct trace_entry *ent) 1073 { 1074 const __u64 *val = pdu_start(ent); 1075 return be64_to_cpu(*val); 1076 } 1077 1078 static void get_pdu_remap(const struct trace_entry *ent, 1079 struct blk_io_trace_remap *r) 1080 { 1081 const struct blk_io_trace_remap *__r = pdu_start(ent); 1082 __u64 sector_from = __r->sector_from; 1083 1084 r->device_from = be32_to_cpu(__r->device_from); 1085 r->device_to = be32_to_cpu(__r->device_to); 1086 r->sector_from = be64_to_cpu(sector_from); 1087 } 1088 1089 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1090 1091 static int blk_log_action_classic(struct trace_iterator *iter, const char *act) 1092 { 1093 char rwbs[6]; 1094 unsigned long long ts = iter->ts; 1095 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1096 unsigned secs = (unsigned long)ts; 1097 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1098 1099 fill_rwbs(rwbs, t); 1100 1101 return trace_seq_printf(&iter->seq, 1102 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1103 MAJOR(t->device), MINOR(t->device), iter->cpu, 1104 secs, nsec_rem, iter->ent->pid, act, rwbs); 1105 } 1106 1107 static int blk_log_action(struct trace_iterator *iter, const char *act) 1108 { 1109 char rwbs[6]; 1110 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1111 1112 fill_rwbs(rwbs, t); 1113 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1114 MAJOR(t->device), MINOR(t->device), act, rwbs); 1115 } 1116 1117 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1118 { 1119 const unsigned char *pdu_buf; 1120 int pdu_len; 1121 int i, end, ret; 1122 1123 pdu_buf = pdu_start(ent); 1124 pdu_len = te_blk_io_trace(ent)->pdu_len; 1125 1126 if (!pdu_len) 1127 return 1; 1128 1129 /* find the last zero that needs to be printed */ 1130 for (end = pdu_len - 1; end >= 0; end--) 1131 if (pdu_buf[end]) 1132 break; 1133 end++; 1134 1135 if (!trace_seq_putc(s, '(')) 1136 return 0; 1137 1138 for (i = 0; i < pdu_len; i++) { 1139 1140 ret = trace_seq_printf(s, "%s%02x", 1141 i == 0 ? "" : " ", pdu_buf[i]); 1142 if (!ret) 1143 return ret; 1144 1145 /* 1146 * stop when the rest is just zeroes and indicate so 1147 * with a ".." appended 1148 */ 1149 if (i == end && end != pdu_len - 1) 1150 return trace_seq_puts(s, " ..) "); 1151 } 1152 1153 return trace_seq_puts(s, ") "); 1154 } 1155 1156 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1157 { 1158 char cmd[TASK_COMM_LEN]; 1159 1160 trace_find_cmdline(ent->pid, cmd); 1161 1162 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1163 int ret; 1164 1165 ret = trace_seq_printf(s, "%u ", t_bytes(ent)); 1166 if (!ret) 1167 return 0; 1168 ret = blk_log_dump_pdu(s, ent); 1169 if (!ret) 1170 return 0; 1171 return trace_seq_printf(s, "[%s]\n", cmd); 1172 } else { 1173 if (t_sec(ent)) 1174 return trace_seq_printf(s, "%llu + %u [%s]\n", 1175 t_sector(ent), t_sec(ent), cmd); 1176 return trace_seq_printf(s, "[%s]\n", cmd); 1177 } 1178 } 1179 1180 static int blk_log_with_error(struct trace_seq *s, 1181 const struct trace_entry *ent) 1182 { 1183 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1184 int ret; 1185 1186 ret = blk_log_dump_pdu(s, ent); 1187 if (ret) 1188 return trace_seq_printf(s, "[%d]\n", t_error(ent)); 1189 return 0; 1190 } else { 1191 if (t_sec(ent)) 1192 return trace_seq_printf(s, "%llu + %u [%d]\n", 1193 t_sector(ent), 1194 t_sec(ent), t_error(ent)); 1195 return trace_seq_printf(s, "%llu [%d]\n", 1196 t_sector(ent), t_error(ent)); 1197 } 1198 } 1199 1200 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1201 { 1202 struct blk_io_trace_remap r = { .device_from = 0, }; 1203 1204 get_pdu_remap(ent, &r); 1205 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1206 t_sector(ent), t_sec(ent), 1207 MAJOR(r.device_from), MINOR(r.device_from), 1208 (unsigned long long)r.sector_from); 1209 } 1210 1211 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1212 { 1213 char cmd[TASK_COMM_LEN]; 1214 1215 trace_find_cmdline(ent->pid, cmd); 1216 1217 return trace_seq_printf(s, "[%s]\n", cmd); 1218 } 1219 1220 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1221 { 1222 char cmd[TASK_COMM_LEN]; 1223 1224 trace_find_cmdline(ent->pid, cmd); 1225 1226 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1227 } 1228 1229 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1230 { 1231 char cmd[TASK_COMM_LEN]; 1232 1233 trace_find_cmdline(ent->pid, cmd); 1234 1235 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1236 get_pdu_int(ent), cmd); 1237 } 1238 1239 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1240 { 1241 int ret; 1242 const struct blk_io_trace *t = te_blk_io_trace(ent); 1243 1244 ret = trace_seq_putmem(s, t + 1, t->pdu_len); 1245 if (ret) 1246 return trace_seq_putc(s, '\n'); 1247 return ret; 1248 } 1249 1250 /* 1251 * struct tracer operations 1252 */ 1253 1254 static void blk_tracer_print_header(struct seq_file *m) 1255 { 1256 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1257 return; 1258 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1259 "# | | | | | |\n"); 1260 } 1261 1262 static void blk_tracer_start(struct trace_array *tr) 1263 { 1264 blk_tracer_enabled = true; 1265 } 1266 1267 static int blk_tracer_init(struct trace_array *tr) 1268 { 1269 blk_tr = tr; 1270 blk_tracer_start(tr); 1271 return 0; 1272 } 1273 1274 static void blk_tracer_stop(struct trace_array *tr) 1275 { 1276 blk_tracer_enabled = false; 1277 } 1278 1279 static void blk_tracer_reset(struct trace_array *tr) 1280 { 1281 blk_tracer_stop(tr); 1282 } 1283 1284 static const struct { 1285 const char *act[2]; 1286 int (*print)(struct trace_seq *s, const struct trace_entry *ent); 1287 } what2act[] = { 1288 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1289 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1290 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1291 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1292 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1293 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1294 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1295 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1296 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1297 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1298 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1299 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1300 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1301 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1302 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1303 }; 1304 1305 static enum print_line_t print_one_line(struct trace_iterator *iter, 1306 bool classic) 1307 { 1308 struct trace_seq *s = &iter->seq; 1309 const struct blk_io_trace *t; 1310 u16 what; 1311 int ret; 1312 bool long_act; 1313 blk_log_action_t *log_action; 1314 1315 t = te_blk_io_trace(iter->ent); 1316 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1317 long_act = !!(trace_flags & TRACE_ITER_VERBOSE); 1318 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1319 1320 if (t->action == BLK_TN_MESSAGE) { 1321 ret = log_action(iter, long_act ? "message" : "m"); 1322 if (ret) 1323 ret = blk_log_msg(s, iter->ent); 1324 goto out; 1325 } 1326 1327 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1328 ret = trace_seq_printf(s, "Unknown action %x\n", what); 1329 else { 1330 ret = log_action(iter, what2act[what].act[long_act]); 1331 if (ret) 1332 ret = what2act[what].print(s, iter->ent); 1333 } 1334 out: 1335 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1336 } 1337 1338 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1339 int flags, struct trace_event *event) 1340 { 1341 return print_one_line(iter, false); 1342 } 1343 1344 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1345 { 1346 struct trace_seq *s = &iter->seq; 1347 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1348 const int offset = offsetof(struct blk_io_trace, sector); 1349 struct blk_io_trace old = { 1350 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1351 .time = iter->ts, 1352 }; 1353 1354 if (!trace_seq_putmem(s, &old, offset)) 1355 return 0; 1356 return trace_seq_putmem(s, &t->sector, 1357 sizeof(old) - offset + t->pdu_len); 1358 } 1359 1360 static enum print_line_t 1361 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1362 struct trace_event *event) 1363 { 1364 return blk_trace_synthesize_old_trace(iter) ? 1365 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1366 } 1367 1368 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1369 { 1370 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1371 return TRACE_TYPE_UNHANDLED; 1372 1373 return print_one_line(iter, true); 1374 } 1375 1376 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set) 1377 { 1378 /* don't output context-info for blk_classic output */ 1379 if (bit == TRACE_BLK_OPT_CLASSIC) { 1380 if (set) 1381 trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1382 else 1383 trace_flags |= TRACE_ITER_CONTEXT_INFO; 1384 } 1385 return 0; 1386 } 1387 1388 static struct tracer blk_tracer __read_mostly = { 1389 .name = "blk", 1390 .init = blk_tracer_init, 1391 .reset = blk_tracer_reset, 1392 .start = blk_tracer_start, 1393 .stop = blk_tracer_stop, 1394 .print_header = blk_tracer_print_header, 1395 .print_line = blk_tracer_print_line, 1396 .flags = &blk_tracer_flags, 1397 .set_flag = blk_tracer_set_flag, 1398 }; 1399 1400 static struct trace_event_functions trace_blk_event_funcs = { 1401 .trace = blk_trace_event_print, 1402 .binary = blk_trace_event_print_binary, 1403 }; 1404 1405 static struct trace_event trace_blk_event = { 1406 .type = TRACE_BLK, 1407 .funcs = &trace_blk_event_funcs, 1408 }; 1409 1410 static int __init init_blk_tracer(void) 1411 { 1412 if (!register_ftrace_event(&trace_blk_event)) { 1413 pr_warning("Warning: could not register block events\n"); 1414 return 1; 1415 } 1416 1417 if (register_tracer(&blk_tracer) != 0) { 1418 pr_warning("Warning: could not register the block tracer\n"); 1419 unregister_ftrace_event(&trace_blk_event); 1420 return 1; 1421 } 1422 1423 return 0; 1424 } 1425 1426 device_initcall(init_blk_tracer); 1427 1428 static int blk_trace_remove_queue(struct request_queue *q) 1429 { 1430 struct blk_trace *bt; 1431 1432 bt = xchg(&q->blk_trace, NULL); 1433 if (bt == NULL) 1434 return -EINVAL; 1435 1436 if (atomic_dec_and_test(&blk_probes_ref)) 1437 blk_unregister_tracepoints(); 1438 1439 blk_trace_free(bt); 1440 return 0; 1441 } 1442 1443 /* 1444 * Setup everything required to start tracing 1445 */ 1446 static int blk_trace_setup_queue(struct request_queue *q, 1447 struct block_device *bdev) 1448 { 1449 struct blk_trace *old_bt, *bt = NULL; 1450 int ret = -ENOMEM; 1451 1452 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1453 if (!bt) 1454 return -ENOMEM; 1455 1456 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1457 if (!bt->msg_data) 1458 goto free_bt; 1459 1460 bt->dev = bdev->bd_dev; 1461 bt->act_mask = (u16)-1; 1462 1463 blk_trace_setup_lba(bt, bdev); 1464 1465 old_bt = xchg(&q->blk_trace, bt); 1466 if (old_bt != NULL) { 1467 (void)xchg(&q->blk_trace, old_bt); 1468 ret = -EBUSY; 1469 goto free_bt; 1470 } 1471 1472 if (atomic_inc_return(&blk_probes_ref) == 1) 1473 blk_register_tracepoints(); 1474 return 0; 1475 1476 free_bt: 1477 blk_trace_free(bt); 1478 return ret; 1479 } 1480 1481 /* 1482 * sysfs interface to enable and configure tracing 1483 */ 1484 1485 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1486 struct device_attribute *attr, 1487 char *buf); 1488 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1489 struct device_attribute *attr, 1490 const char *buf, size_t count); 1491 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1492 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1493 sysfs_blk_trace_attr_show, \ 1494 sysfs_blk_trace_attr_store) 1495 1496 static BLK_TRACE_DEVICE_ATTR(enable); 1497 static BLK_TRACE_DEVICE_ATTR(act_mask); 1498 static BLK_TRACE_DEVICE_ATTR(pid); 1499 static BLK_TRACE_DEVICE_ATTR(start_lba); 1500 static BLK_TRACE_DEVICE_ATTR(end_lba); 1501 1502 static struct attribute *blk_trace_attrs[] = { 1503 &dev_attr_enable.attr, 1504 &dev_attr_act_mask.attr, 1505 &dev_attr_pid.attr, 1506 &dev_attr_start_lba.attr, 1507 &dev_attr_end_lba.attr, 1508 NULL 1509 }; 1510 1511 struct attribute_group blk_trace_attr_group = { 1512 .name = "trace", 1513 .attrs = blk_trace_attrs, 1514 }; 1515 1516 static const struct { 1517 int mask; 1518 const char *str; 1519 } mask_maps[] = { 1520 { BLK_TC_READ, "read" }, 1521 { BLK_TC_WRITE, "write" }, 1522 { BLK_TC_BARRIER, "barrier" }, 1523 { BLK_TC_SYNC, "sync" }, 1524 { BLK_TC_QUEUE, "queue" }, 1525 { BLK_TC_REQUEUE, "requeue" }, 1526 { BLK_TC_ISSUE, "issue" }, 1527 { BLK_TC_COMPLETE, "complete" }, 1528 { BLK_TC_FS, "fs" }, 1529 { BLK_TC_PC, "pc" }, 1530 { BLK_TC_AHEAD, "ahead" }, 1531 { BLK_TC_META, "meta" }, 1532 { BLK_TC_DISCARD, "discard" }, 1533 { BLK_TC_DRV_DATA, "drv_data" }, 1534 }; 1535 1536 static int blk_trace_str2mask(const char *str) 1537 { 1538 int i; 1539 int mask = 0; 1540 char *buf, *s, *token; 1541 1542 buf = kstrdup(str, GFP_KERNEL); 1543 if (buf == NULL) 1544 return -ENOMEM; 1545 s = strstrip(buf); 1546 1547 while (1) { 1548 token = strsep(&s, ","); 1549 if (token == NULL) 1550 break; 1551 1552 if (*token == '\0') 1553 continue; 1554 1555 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1556 if (strcasecmp(token, mask_maps[i].str) == 0) { 1557 mask |= mask_maps[i].mask; 1558 break; 1559 } 1560 } 1561 if (i == ARRAY_SIZE(mask_maps)) { 1562 mask = -EINVAL; 1563 break; 1564 } 1565 } 1566 kfree(buf); 1567 1568 return mask; 1569 } 1570 1571 static ssize_t blk_trace_mask2str(char *buf, int mask) 1572 { 1573 int i; 1574 char *p = buf; 1575 1576 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1577 if (mask & mask_maps[i].mask) { 1578 p += sprintf(p, "%s%s", 1579 (p == buf) ? "" : ",", mask_maps[i].str); 1580 } 1581 } 1582 *p++ = '\n'; 1583 1584 return p - buf; 1585 } 1586 1587 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1588 { 1589 if (bdev->bd_disk == NULL) 1590 return NULL; 1591 1592 return bdev_get_queue(bdev); 1593 } 1594 1595 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1596 struct device_attribute *attr, 1597 char *buf) 1598 { 1599 struct hd_struct *p = dev_to_part(dev); 1600 struct request_queue *q; 1601 struct block_device *bdev; 1602 ssize_t ret = -ENXIO; 1603 1604 lock_kernel(); 1605 bdev = bdget(part_devt(p)); 1606 if (bdev == NULL) 1607 goto out_unlock_kernel; 1608 1609 q = blk_trace_get_queue(bdev); 1610 if (q == NULL) 1611 goto out_bdput; 1612 1613 mutex_lock(&bdev->bd_mutex); 1614 1615 if (attr == &dev_attr_enable) { 1616 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1617 goto out_unlock_bdev; 1618 } 1619 1620 if (q->blk_trace == NULL) 1621 ret = sprintf(buf, "disabled\n"); 1622 else if (attr == &dev_attr_act_mask) 1623 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1624 else if (attr == &dev_attr_pid) 1625 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1626 else if (attr == &dev_attr_start_lba) 1627 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1628 else if (attr == &dev_attr_end_lba) 1629 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1630 1631 out_unlock_bdev: 1632 mutex_unlock(&bdev->bd_mutex); 1633 out_bdput: 1634 bdput(bdev); 1635 out_unlock_kernel: 1636 unlock_kernel(); 1637 return ret; 1638 } 1639 1640 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1641 struct device_attribute *attr, 1642 const char *buf, size_t count) 1643 { 1644 struct block_device *bdev; 1645 struct request_queue *q; 1646 struct hd_struct *p; 1647 u64 value; 1648 ssize_t ret = -EINVAL; 1649 1650 if (count == 0) 1651 goto out; 1652 1653 if (attr == &dev_attr_act_mask) { 1654 if (sscanf(buf, "%llx", &value) != 1) { 1655 /* Assume it is a list of trace category names */ 1656 ret = blk_trace_str2mask(buf); 1657 if (ret < 0) 1658 goto out; 1659 value = ret; 1660 } 1661 } else if (sscanf(buf, "%llu", &value) != 1) 1662 goto out; 1663 1664 ret = -ENXIO; 1665 1666 lock_kernel(); 1667 p = dev_to_part(dev); 1668 bdev = bdget(part_devt(p)); 1669 if (bdev == NULL) 1670 goto out_unlock_kernel; 1671 1672 q = blk_trace_get_queue(bdev); 1673 if (q == NULL) 1674 goto out_bdput; 1675 1676 mutex_lock(&bdev->bd_mutex); 1677 1678 if (attr == &dev_attr_enable) { 1679 if (value) 1680 ret = blk_trace_setup_queue(q, bdev); 1681 else 1682 ret = blk_trace_remove_queue(q); 1683 goto out_unlock_bdev; 1684 } 1685 1686 ret = 0; 1687 if (q->blk_trace == NULL) 1688 ret = blk_trace_setup_queue(q, bdev); 1689 1690 if (ret == 0) { 1691 if (attr == &dev_attr_act_mask) 1692 q->blk_trace->act_mask = value; 1693 else if (attr == &dev_attr_pid) 1694 q->blk_trace->pid = value; 1695 else if (attr == &dev_attr_start_lba) 1696 q->blk_trace->start_lba = value; 1697 else if (attr == &dev_attr_end_lba) 1698 q->blk_trace->end_lba = value; 1699 } 1700 1701 out_unlock_bdev: 1702 mutex_unlock(&bdev->bd_mutex); 1703 out_bdput: 1704 bdput(bdev); 1705 out_unlock_kernel: 1706 unlock_kernel(); 1707 out: 1708 return ret ? ret : count; 1709 } 1710 1711 int blk_trace_init_sysfs(struct device *dev) 1712 { 1713 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1714 } 1715 1716 void blk_trace_remove_sysfs(struct device *dev) 1717 { 1718 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1719 } 1720 1721 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1722 1723 #ifdef CONFIG_EVENT_TRACING 1724 1725 void blk_dump_cmd(char *buf, struct request *rq) 1726 { 1727 int i, end; 1728 int len = rq->cmd_len; 1729 unsigned char *cmd = rq->cmd; 1730 1731 if (!blk_pc_request(rq)) { 1732 buf[0] = '\0'; 1733 return; 1734 } 1735 1736 for (end = len - 1; end >= 0; end--) 1737 if (cmd[end]) 1738 break; 1739 end++; 1740 1741 for (i = 0; i < len; i++) { 1742 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1743 if (i == end && end != len - 1) { 1744 sprintf(buf, " .."); 1745 break; 1746 } 1747 } 1748 } 1749 1750 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) 1751 { 1752 int i = 0; 1753 1754 if (rw & WRITE) 1755 rwbs[i++] = 'W'; 1756 else if (rw & 1 << BIO_RW_DISCARD) 1757 rwbs[i++] = 'D'; 1758 else if (bytes) 1759 rwbs[i++] = 'R'; 1760 else 1761 rwbs[i++] = 'N'; 1762 1763 if (rw & 1 << BIO_RW_AHEAD) 1764 rwbs[i++] = 'A'; 1765 if (rw & 1 << BIO_RW_BARRIER) 1766 rwbs[i++] = 'B'; 1767 if (rw & 1 << BIO_RW_SYNCIO) 1768 rwbs[i++] = 'S'; 1769 if (rw & 1 << BIO_RW_META) 1770 rwbs[i++] = 'M'; 1771 1772 rwbs[i] = '\0'; 1773 } 1774 1775 void blk_fill_rwbs_rq(char *rwbs, struct request *rq) 1776 { 1777 int rw = rq->cmd_flags & 0x03; 1778 int bytes; 1779 1780 if (blk_discard_rq(rq)) 1781 rw |= (1 << BIO_RW_DISCARD); 1782 1783 bytes = blk_rq_bytes(rq); 1784 1785 blk_fill_rwbs(rwbs, rw, bytes); 1786 } 1787 1788 #endif /* CONFIG_EVENT_TRACING */ 1789 1790