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 * @ignore: trace callback data parameter (not used) 846 * @q: queue the io is for 847 * @bio: the source bio 848 * @dev: target device 849 * @from: source sector 850 * 851 * Description: 852 * Device mapper or raid target sometimes need to split a bio because 853 * it spans a stripe (or similar). Add a trace for that action. 854 * 855 **/ 856 static void blk_add_trace_remap(void *ignore, 857 struct request_queue *q, struct bio *bio, 858 dev_t dev, sector_t from) 859 { 860 struct blk_trace *bt = q->blk_trace; 861 struct blk_io_trace_remap r; 862 863 if (likely(!bt)) 864 return; 865 866 r.device_from = cpu_to_be32(dev); 867 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 868 r.sector_from = cpu_to_be64(from); 869 870 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 871 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), 872 sizeof(r), &r); 873 } 874 875 /** 876 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 877 * @ignore: trace callback data parameter (not used) 878 * @q: queue the io is for 879 * @rq: the source request 880 * @dev: target device 881 * @from: source sector 882 * 883 * Description: 884 * Device mapper remaps request to other devices. 885 * Add a trace for that action. 886 * 887 **/ 888 static void blk_add_trace_rq_remap(void *ignore, 889 struct request_queue *q, 890 struct request *rq, dev_t dev, 891 sector_t from) 892 { 893 struct blk_trace *bt = q->blk_trace; 894 struct blk_io_trace_remap r; 895 896 if (likely(!bt)) 897 return; 898 899 r.device_from = cpu_to_be32(dev); 900 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 901 r.sector_from = cpu_to_be64(from); 902 903 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 904 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors, 905 sizeof(r), &r); 906 } 907 908 /** 909 * blk_add_driver_data - Add binary message with driver-specific data 910 * @q: queue the io is for 911 * @rq: io request 912 * @data: driver-specific data 913 * @len: length of driver-specific data 914 * 915 * Description: 916 * Some drivers might want to write driver-specific data per request. 917 * 918 **/ 919 void blk_add_driver_data(struct request_queue *q, 920 struct request *rq, 921 void *data, size_t len) 922 { 923 struct blk_trace *bt = q->blk_trace; 924 925 if (likely(!bt)) 926 return; 927 928 if (blk_pc_request(rq)) 929 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 930 BLK_TA_DRV_DATA, rq->errors, len, data); 931 else 932 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 933 BLK_TA_DRV_DATA, rq->errors, len, data); 934 } 935 EXPORT_SYMBOL_GPL(blk_add_driver_data); 936 937 static void blk_register_tracepoints(void) 938 { 939 int ret; 940 941 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 942 WARN_ON(ret); 943 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 944 WARN_ON(ret); 945 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 946 WARN_ON(ret); 947 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 948 WARN_ON(ret); 949 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 950 WARN_ON(ret); 951 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 952 WARN_ON(ret); 953 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 954 WARN_ON(ret); 955 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 956 WARN_ON(ret); 957 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 958 WARN_ON(ret); 959 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 960 WARN_ON(ret); 961 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 962 WARN_ON(ret); 963 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 964 WARN_ON(ret); 965 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 966 WARN_ON(ret); 967 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL); 968 WARN_ON(ret); 969 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); 970 WARN_ON(ret); 971 ret = register_trace_block_split(blk_add_trace_split, NULL); 972 WARN_ON(ret); 973 ret = register_trace_block_remap(blk_add_trace_remap, NULL); 974 WARN_ON(ret); 975 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 976 WARN_ON(ret); 977 } 978 979 static void blk_unregister_tracepoints(void) 980 { 981 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 982 unregister_trace_block_remap(blk_add_trace_remap, NULL); 983 unregister_trace_block_split(blk_add_trace_split, NULL); 984 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); 985 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL); 986 unregister_trace_block_plug(blk_add_trace_plug, NULL); 987 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 988 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 989 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 990 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 991 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 992 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 993 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 994 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 995 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 996 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 997 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 998 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 999 1000 tracepoint_synchronize_unregister(); 1001 } 1002 1003 /* 1004 * struct blk_io_tracer formatting routines 1005 */ 1006 1007 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1008 { 1009 int i = 0; 1010 int tc = t->action >> BLK_TC_SHIFT; 1011 1012 if (t->action == BLK_TN_MESSAGE) { 1013 rwbs[i++] = 'N'; 1014 goto out; 1015 } 1016 1017 if (tc & BLK_TC_DISCARD) 1018 rwbs[i++] = 'D'; 1019 else if (tc & BLK_TC_WRITE) 1020 rwbs[i++] = 'W'; 1021 else if (t->bytes) 1022 rwbs[i++] = 'R'; 1023 else 1024 rwbs[i++] = 'N'; 1025 1026 if (tc & BLK_TC_AHEAD) 1027 rwbs[i++] = 'A'; 1028 if (tc & BLK_TC_BARRIER) 1029 rwbs[i++] = 'B'; 1030 if (tc & BLK_TC_SYNC) 1031 rwbs[i++] = 'S'; 1032 if (tc & BLK_TC_META) 1033 rwbs[i++] = 'M'; 1034 out: 1035 rwbs[i] = '\0'; 1036 } 1037 1038 static inline 1039 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1040 { 1041 return (const struct blk_io_trace *)ent; 1042 } 1043 1044 static inline const void *pdu_start(const struct trace_entry *ent) 1045 { 1046 return te_blk_io_trace(ent) + 1; 1047 } 1048 1049 static inline u32 t_action(const struct trace_entry *ent) 1050 { 1051 return te_blk_io_trace(ent)->action; 1052 } 1053 1054 static inline u32 t_bytes(const struct trace_entry *ent) 1055 { 1056 return te_blk_io_trace(ent)->bytes; 1057 } 1058 1059 static inline u32 t_sec(const struct trace_entry *ent) 1060 { 1061 return te_blk_io_trace(ent)->bytes >> 9; 1062 } 1063 1064 static inline unsigned long long t_sector(const struct trace_entry *ent) 1065 { 1066 return te_blk_io_trace(ent)->sector; 1067 } 1068 1069 static inline __u16 t_error(const struct trace_entry *ent) 1070 { 1071 return te_blk_io_trace(ent)->error; 1072 } 1073 1074 static __u64 get_pdu_int(const struct trace_entry *ent) 1075 { 1076 const __u64 *val = pdu_start(ent); 1077 return be64_to_cpu(*val); 1078 } 1079 1080 static void get_pdu_remap(const struct trace_entry *ent, 1081 struct blk_io_trace_remap *r) 1082 { 1083 const struct blk_io_trace_remap *__r = pdu_start(ent); 1084 __u64 sector_from = __r->sector_from; 1085 1086 r->device_from = be32_to_cpu(__r->device_from); 1087 r->device_to = be32_to_cpu(__r->device_to); 1088 r->sector_from = be64_to_cpu(sector_from); 1089 } 1090 1091 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1092 1093 static int blk_log_action_classic(struct trace_iterator *iter, const char *act) 1094 { 1095 char rwbs[6]; 1096 unsigned long long ts = iter->ts; 1097 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1098 unsigned secs = (unsigned long)ts; 1099 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1100 1101 fill_rwbs(rwbs, t); 1102 1103 return trace_seq_printf(&iter->seq, 1104 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1105 MAJOR(t->device), MINOR(t->device), iter->cpu, 1106 secs, nsec_rem, iter->ent->pid, act, rwbs); 1107 } 1108 1109 static int blk_log_action(struct trace_iterator *iter, const char *act) 1110 { 1111 char rwbs[6]; 1112 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1113 1114 fill_rwbs(rwbs, t); 1115 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1116 MAJOR(t->device), MINOR(t->device), act, rwbs); 1117 } 1118 1119 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1120 { 1121 const unsigned char *pdu_buf; 1122 int pdu_len; 1123 int i, end, ret; 1124 1125 pdu_buf = pdu_start(ent); 1126 pdu_len = te_blk_io_trace(ent)->pdu_len; 1127 1128 if (!pdu_len) 1129 return 1; 1130 1131 /* find the last zero that needs to be printed */ 1132 for (end = pdu_len - 1; end >= 0; end--) 1133 if (pdu_buf[end]) 1134 break; 1135 end++; 1136 1137 if (!trace_seq_putc(s, '(')) 1138 return 0; 1139 1140 for (i = 0; i < pdu_len; i++) { 1141 1142 ret = trace_seq_printf(s, "%s%02x", 1143 i == 0 ? "" : " ", pdu_buf[i]); 1144 if (!ret) 1145 return ret; 1146 1147 /* 1148 * stop when the rest is just zeroes and indicate so 1149 * with a ".." appended 1150 */ 1151 if (i == end && end != pdu_len - 1) 1152 return trace_seq_puts(s, " ..) "); 1153 } 1154 1155 return trace_seq_puts(s, ") "); 1156 } 1157 1158 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1159 { 1160 char cmd[TASK_COMM_LEN]; 1161 1162 trace_find_cmdline(ent->pid, cmd); 1163 1164 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1165 int ret; 1166 1167 ret = trace_seq_printf(s, "%u ", t_bytes(ent)); 1168 if (!ret) 1169 return 0; 1170 ret = blk_log_dump_pdu(s, ent); 1171 if (!ret) 1172 return 0; 1173 return trace_seq_printf(s, "[%s]\n", cmd); 1174 } else { 1175 if (t_sec(ent)) 1176 return trace_seq_printf(s, "%llu + %u [%s]\n", 1177 t_sector(ent), t_sec(ent), cmd); 1178 return trace_seq_printf(s, "[%s]\n", cmd); 1179 } 1180 } 1181 1182 static int blk_log_with_error(struct trace_seq *s, 1183 const struct trace_entry *ent) 1184 { 1185 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1186 int ret; 1187 1188 ret = blk_log_dump_pdu(s, ent); 1189 if (ret) 1190 return trace_seq_printf(s, "[%d]\n", t_error(ent)); 1191 return 0; 1192 } else { 1193 if (t_sec(ent)) 1194 return trace_seq_printf(s, "%llu + %u [%d]\n", 1195 t_sector(ent), 1196 t_sec(ent), t_error(ent)); 1197 return trace_seq_printf(s, "%llu [%d]\n", 1198 t_sector(ent), t_error(ent)); 1199 } 1200 } 1201 1202 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1203 { 1204 struct blk_io_trace_remap r = { .device_from = 0, }; 1205 1206 get_pdu_remap(ent, &r); 1207 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1208 t_sector(ent), t_sec(ent), 1209 MAJOR(r.device_from), MINOR(r.device_from), 1210 (unsigned long long)r.sector_from); 1211 } 1212 1213 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1214 { 1215 char cmd[TASK_COMM_LEN]; 1216 1217 trace_find_cmdline(ent->pid, cmd); 1218 1219 return trace_seq_printf(s, "[%s]\n", cmd); 1220 } 1221 1222 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1223 { 1224 char cmd[TASK_COMM_LEN]; 1225 1226 trace_find_cmdline(ent->pid, cmd); 1227 1228 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1229 } 1230 1231 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1232 { 1233 char cmd[TASK_COMM_LEN]; 1234 1235 trace_find_cmdline(ent->pid, cmd); 1236 1237 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1238 get_pdu_int(ent), cmd); 1239 } 1240 1241 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1242 { 1243 int ret; 1244 const struct blk_io_trace *t = te_blk_io_trace(ent); 1245 1246 ret = trace_seq_putmem(s, t + 1, t->pdu_len); 1247 if (ret) 1248 return trace_seq_putc(s, '\n'); 1249 return ret; 1250 } 1251 1252 /* 1253 * struct tracer operations 1254 */ 1255 1256 static void blk_tracer_print_header(struct seq_file *m) 1257 { 1258 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1259 return; 1260 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1261 "# | | | | | |\n"); 1262 } 1263 1264 static void blk_tracer_start(struct trace_array *tr) 1265 { 1266 blk_tracer_enabled = true; 1267 } 1268 1269 static int blk_tracer_init(struct trace_array *tr) 1270 { 1271 blk_tr = tr; 1272 blk_tracer_start(tr); 1273 return 0; 1274 } 1275 1276 static void blk_tracer_stop(struct trace_array *tr) 1277 { 1278 blk_tracer_enabled = false; 1279 } 1280 1281 static void blk_tracer_reset(struct trace_array *tr) 1282 { 1283 blk_tracer_stop(tr); 1284 } 1285 1286 static const struct { 1287 const char *act[2]; 1288 int (*print)(struct trace_seq *s, const struct trace_entry *ent); 1289 } what2act[] = { 1290 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1291 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1292 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1293 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1294 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1295 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1296 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1297 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1298 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1299 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1300 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1301 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1302 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1303 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1304 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1305 }; 1306 1307 static enum print_line_t print_one_line(struct trace_iterator *iter, 1308 bool classic) 1309 { 1310 struct trace_seq *s = &iter->seq; 1311 const struct blk_io_trace *t; 1312 u16 what; 1313 int ret; 1314 bool long_act; 1315 blk_log_action_t *log_action; 1316 1317 t = te_blk_io_trace(iter->ent); 1318 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1319 long_act = !!(trace_flags & TRACE_ITER_VERBOSE); 1320 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1321 1322 if (t->action == BLK_TN_MESSAGE) { 1323 ret = log_action(iter, long_act ? "message" : "m"); 1324 if (ret) 1325 ret = blk_log_msg(s, iter->ent); 1326 goto out; 1327 } 1328 1329 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1330 ret = trace_seq_printf(s, "Unknown action %x\n", what); 1331 else { 1332 ret = log_action(iter, what2act[what].act[long_act]); 1333 if (ret) 1334 ret = what2act[what].print(s, iter->ent); 1335 } 1336 out: 1337 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1338 } 1339 1340 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1341 int flags, struct trace_event *event) 1342 { 1343 return print_one_line(iter, false); 1344 } 1345 1346 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1347 { 1348 struct trace_seq *s = &iter->seq; 1349 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1350 const int offset = offsetof(struct blk_io_trace, sector); 1351 struct blk_io_trace old = { 1352 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1353 .time = iter->ts, 1354 }; 1355 1356 if (!trace_seq_putmem(s, &old, offset)) 1357 return 0; 1358 return trace_seq_putmem(s, &t->sector, 1359 sizeof(old) - offset + t->pdu_len); 1360 } 1361 1362 static enum print_line_t 1363 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1364 struct trace_event *event) 1365 { 1366 return blk_trace_synthesize_old_trace(iter) ? 1367 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1368 } 1369 1370 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1371 { 1372 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1373 return TRACE_TYPE_UNHANDLED; 1374 1375 return print_one_line(iter, true); 1376 } 1377 1378 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set) 1379 { 1380 /* don't output context-info for blk_classic output */ 1381 if (bit == TRACE_BLK_OPT_CLASSIC) { 1382 if (set) 1383 trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1384 else 1385 trace_flags |= TRACE_ITER_CONTEXT_INFO; 1386 } 1387 return 0; 1388 } 1389 1390 static struct tracer blk_tracer __read_mostly = { 1391 .name = "blk", 1392 .init = blk_tracer_init, 1393 .reset = blk_tracer_reset, 1394 .start = blk_tracer_start, 1395 .stop = blk_tracer_stop, 1396 .print_header = blk_tracer_print_header, 1397 .print_line = blk_tracer_print_line, 1398 .flags = &blk_tracer_flags, 1399 .set_flag = blk_tracer_set_flag, 1400 }; 1401 1402 static struct trace_event_functions trace_blk_event_funcs = { 1403 .trace = blk_trace_event_print, 1404 .binary = blk_trace_event_print_binary, 1405 }; 1406 1407 static struct trace_event trace_blk_event = { 1408 .type = TRACE_BLK, 1409 .funcs = &trace_blk_event_funcs, 1410 }; 1411 1412 static int __init init_blk_tracer(void) 1413 { 1414 if (!register_ftrace_event(&trace_blk_event)) { 1415 pr_warning("Warning: could not register block events\n"); 1416 return 1; 1417 } 1418 1419 if (register_tracer(&blk_tracer) != 0) { 1420 pr_warning("Warning: could not register the block tracer\n"); 1421 unregister_ftrace_event(&trace_blk_event); 1422 return 1; 1423 } 1424 1425 return 0; 1426 } 1427 1428 device_initcall(init_blk_tracer); 1429 1430 static int blk_trace_remove_queue(struct request_queue *q) 1431 { 1432 struct blk_trace *bt; 1433 1434 bt = xchg(&q->blk_trace, NULL); 1435 if (bt == NULL) 1436 return -EINVAL; 1437 1438 if (atomic_dec_and_test(&blk_probes_ref)) 1439 blk_unregister_tracepoints(); 1440 1441 blk_trace_free(bt); 1442 return 0; 1443 } 1444 1445 /* 1446 * Setup everything required to start tracing 1447 */ 1448 static int blk_trace_setup_queue(struct request_queue *q, 1449 struct block_device *bdev) 1450 { 1451 struct blk_trace *old_bt, *bt = NULL; 1452 int ret = -ENOMEM; 1453 1454 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1455 if (!bt) 1456 return -ENOMEM; 1457 1458 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1459 if (!bt->msg_data) 1460 goto free_bt; 1461 1462 bt->dev = bdev->bd_dev; 1463 bt->act_mask = (u16)-1; 1464 1465 blk_trace_setup_lba(bt, bdev); 1466 1467 old_bt = xchg(&q->blk_trace, bt); 1468 if (old_bt != NULL) { 1469 (void)xchg(&q->blk_trace, old_bt); 1470 ret = -EBUSY; 1471 goto free_bt; 1472 } 1473 1474 if (atomic_inc_return(&blk_probes_ref) == 1) 1475 blk_register_tracepoints(); 1476 return 0; 1477 1478 free_bt: 1479 blk_trace_free(bt); 1480 return ret; 1481 } 1482 1483 /* 1484 * sysfs interface to enable and configure tracing 1485 */ 1486 1487 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1488 struct device_attribute *attr, 1489 char *buf); 1490 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1491 struct device_attribute *attr, 1492 const char *buf, size_t count); 1493 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1494 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1495 sysfs_blk_trace_attr_show, \ 1496 sysfs_blk_trace_attr_store) 1497 1498 static BLK_TRACE_DEVICE_ATTR(enable); 1499 static BLK_TRACE_DEVICE_ATTR(act_mask); 1500 static BLK_TRACE_DEVICE_ATTR(pid); 1501 static BLK_TRACE_DEVICE_ATTR(start_lba); 1502 static BLK_TRACE_DEVICE_ATTR(end_lba); 1503 1504 static struct attribute *blk_trace_attrs[] = { 1505 &dev_attr_enable.attr, 1506 &dev_attr_act_mask.attr, 1507 &dev_attr_pid.attr, 1508 &dev_attr_start_lba.attr, 1509 &dev_attr_end_lba.attr, 1510 NULL 1511 }; 1512 1513 struct attribute_group blk_trace_attr_group = { 1514 .name = "trace", 1515 .attrs = blk_trace_attrs, 1516 }; 1517 1518 static const struct { 1519 int mask; 1520 const char *str; 1521 } mask_maps[] = { 1522 { BLK_TC_READ, "read" }, 1523 { BLK_TC_WRITE, "write" }, 1524 { BLK_TC_BARRIER, "barrier" }, 1525 { BLK_TC_SYNC, "sync" }, 1526 { BLK_TC_QUEUE, "queue" }, 1527 { BLK_TC_REQUEUE, "requeue" }, 1528 { BLK_TC_ISSUE, "issue" }, 1529 { BLK_TC_COMPLETE, "complete" }, 1530 { BLK_TC_FS, "fs" }, 1531 { BLK_TC_PC, "pc" }, 1532 { BLK_TC_AHEAD, "ahead" }, 1533 { BLK_TC_META, "meta" }, 1534 { BLK_TC_DISCARD, "discard" }, 1535 { BLK_TC_DRV_DATA, "drv_data" }, 1536 }; 1537 1538 static int blk_trace_str2mask(const char *str) 1539 { 1540 int i; 1541 int mask = 0; 1542 char *buf, *s, *token; 1543 1544 buf = kstrdup(str, GFP_KERNEL); 1545 if (buf == NULL) 1546 return -ENOMEM; 1547 s = strstrip(buf); 1548 1549 while (1) { 1550 token = strsep(&s, ","); 1551 if (token == NULL) 1552 break; 1553 1554 if (*token == '\0') 1555 continue; 1556 1557 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1558 if (strcasecmp(token, mask_maps[i].str) == 0) { 1559 mask |= mask_maps[i].mask; 1560 break; 1561 } 1562 } 1563 if (i == ARRAY_SIZE(mask_maps)) { 1564 mask = -EINVAL; 1565 break; 1566 } 1567 } 1568 kfree(buf); 1569 1570 return mask; 1571 } 1572 1573 static ssize_t blk_trace_mask2str(char *buf, int mask) 1574 { 1575 int i; 1576 char *p = buf; 1577 1578 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1579 if (mask & mask_maps[i].mask) { 1580 p += sprintf(p, "%s%s", 1581 (p == buf) ? "" : ",", mask_maps[i].str); 1582 } 1583 } 1584 *p++ = '\n'; 1585 1586 return p - buf; 1587 } 1588 1589 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1590 { 1591 if (bdev->bd_disk == NULL) 1592 return NULL; 1593 1594 return bdev_get_queue(bdev); 1595 } 1596 1597 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1598 struct device_attribute *attr, 1599 char *buf) 1600 { 1601 struct hd_struct *p = dev_to_part(dev); 1602 struct request_queue *q; 1603 struct block_device *bdev; 1604 ssize_t ret = -ENXIO; 1605 1606 lock_kernel(); 1607 bdev = bdget(part_devt(p)); 1608 if (bdev == NULL) 1609 goto out_unlock_kernel; 1610 1611 q = blk_trace_get_queue(bdev); 1612 if (q == NULL) 1613 goto out_bdput; 1614 1615 mutex_lock(&bdev->bd_mutex); 1616 1617 if (attr == &dev_attr_enable) { 1618 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1619 goto out_unlock_bdev; 1620 } 1621 1622 if (q->blk_trace == NULL) 1623 ret = sprintf(buf, "disabled\n"); 1624 else if (attr == &dev_attr_act_mask) 1625 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1626 else if (attr == &dev_attr_pid) 1627 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1628 else if (attr == &dev_attr_start_lba) 1629 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1630 else if (attr == &dev_attr_end_lba) 1631 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1632 1633 out_unlock_bdev: 1634 mutex_unlock(&bdev->bd_mutex); 1635 out_bdput: 1636 bdput(bdev); 1637 out_unlock_kernel: 1638 unlock_kernel(); 1639 return ret; 1640 } 1641 1642 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1643 struct device_attribute *attr, 1644 const char *buf, size_t count) 1645 { 1646 struct block_device *bdev; 1647 struct request_queue *q; 1648 struct hd_struct *p; 1649 u64 value; 1650 ssize_t ret = -EINVAL; 1651 1652 if (count == 0) 1653 goto out; 1654 1655 if (attr == &dev_attr_act_mask) { 1656 if (sscanf(buf, "%llx", &value) != 1) { 1657 /* Assume it is a list of trace category names */ 1658 ret = blk_trace_str2mask(buf); 1659 if (ret < 0) 1660 goto out; 1661 value = ret; 1662 } 1663 } else if (sscanf(buf, "%llu", &value) != 1) 1664 goto out; 1665 1666 ret = -ENXIO; 1667 1668 lock_kernel(); 1669 p = dev_to_part(dev); 1670 bdev = bdget(part_devt(p)); 1671 if (bdev == NULL) 1672 goto out_unlock_kernel; 1673 1674 q = blk_trace_get_queue(bdev); 1675 if (q == NULL) 1676 goto out_bdput; 1677 1678 mutex_lock(&bdev->bd_mutex); 1679 1680 if (attr == &dev_attr_enable) { 1681 if (value) 1682 ret = blk_trace_setup_queue(q, bdev); 1683 else 1684 ret = blk_trace_remove_queue(q); 1685 goto out_unlock_bdev; 1686 } 1687 1688 ret = 0; 1689 if (q->blk_trace == NULL) 1690 ret = blk_trace_setup_queue(q, bdev); 1691 1692 if (ret == 0) { 1693 if (attr == &dev_attr_act_mask) 1694 q->blk_trace->act_mask = value; 1695 else if (attr == &dev_attr_pid) 1696 q->blk_trace->pid = value; 1697 else if (attr == &dev_attr_start_lba) 1698 q->blk_trace->start_lba = value; 1699 else if (attr == &dev_attr_end_lba) 1700 q->blk_trace->end_lba = value; 1701 } 1702 1703 out_unlock_bdev: 1704 mutex_unlock(&bdev->bd_mutex); 1705 out_bdput: 1706 bdput(bdev); 1707 out_unlock_kernel: 1708 unlock_kernel(); 1709 out: 1710 return ret ? ret : count; 1711 } 1712 1713 int blk_trace_init_sysfs(struct device *dev) 1714 { 1715 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1716 } 1717 1718 void blk_trace_remove_sysfs(struct device *dev) 1719 { 1720 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1721 } 1722 1723 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1724 1725 #ifdef CONFIG_EVENT_TRACING 1726 1727 void blk_dump_cmd(char *buf, struct request *rq) 1728 { 1729 int i, end; 1730 int len = rq->cmd_len; 1731 unsigned char *cmd = rq->cmd; 1732 1733 if (!blk_pc_request(rq)) { 1734 buf[0] = '\0'; 1735 return; 1736 } 1737 1738 for (end = len - 1; end >= 0; end--) 1739 if (cmd[end]) 1740 break; 1741 end++; 1742 1743 for (i = 0; i < len; i++) { 1744 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1745 if (i == end && end != len - 1) { 1746 sprintf(buf, " .."); 1747 break; 1748 } 1749 } 1750 } 1751 1752 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) 1753 { 1754 int i = 0; 1755 1756 if (rw & WRITE) 1757 rwbs[i++] = 'W'; 1758 else if (rw & 1 << BIO_RW_DISCARD) 1759 rwbs[i++] = 'D'; 1760 else if (bytes) 1761 rwbs[i++] = 'R'; 1762 else 1763 rwbs[i++] = 'N'; 1764 1765 if (rw & 1 << BIO_RW_AHEAD) 1766 rwbs[i++] = 'A'; 1767 if (rw & 1 << BIO_RW_BARRIER) 1768 rwbs[i++] = 'B'; 1769 if (rw & 1 << BIO_RW_SYNCIO) 1770 rwbs[i++] = 'S'; 1771 if (rw & 1 << BIO_RW_META) 1772 rwbs[i++] = 'M'; 1773 1774 rwbs[i] = '\0'; 1775 } 1776 1777 void blk_fill_rwbs_rq(char *rwbs, struct request *rq) 1778 { 1779 int rw = rq->cmd_flags & 0x03; 1780 int bytes; 1781 1782 if (blk_discard_rq(rq)) 1783 rw |= (1 << BIO_RW_DISCARD); 1784 1785 bytes = blk_rq_bytes(rq); 1786 1787 blk_fill_rwbs(rwbs, rw, bytes); 1788 } 1789 1790 #endif /* CONFIG_EVENT_TRACING */ 1791 1792