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/debugfs.h> 25 #include <linux/smp_lock.h> 26 #include <linux/time.h> 27 #include <linux/uaccess.h> 28 29 #include <trace/events/block.h> 30 31 #include "trace_output.h" 32 33 #ifdef CONFIG_BLK_DEV_IO_TRACE 34 35 static unsigned int blktrace_seq __read_mostly = 1; 36 37 static struct trace_array *blk_tr; 38 static bool blk_tracer_enabled __read_mostly; 39 40 /* Select an alternative, minimalistic output than the original one */ 41 #define TRACE_BLK_OPT_CLASSIC 0x1 42 43 static struct tracer_opt blk_tracer_opts[] = { 44 /* Default disable the minimalistic output */ 45 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 46 { } 47 }; 48 49 static struct tracer_flags blk_tracer_flags = { 50 .val = 0, 51 .opts = blk_tracer_opts, 52 }; 53 54 /* Global reference count of probes */ 55 static atomic_t blk_probes_ref = ATOMIC_INIT(0); 56 57 static void blk_register_tracepoints(void); 58 static void blk_unregister_tracepoints(void); 59 60 /* 61 * Send out a notify message. 62 */ 63 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 64 const void *data, size_t len) 65 { 66 struct blk_io_trace *t; 67 struct ring_buffer_event *event = NULL; 68 struct ring_buffer *buffer = NULL; 69 int pc = 0; 70 int cpu = smp_processor_id(); 71 bool blk_tracer = blk_tracer_enabled; 72 73 if (blk_tracer) { 74 buffer = blk_tr->buffer; 75 pc = preempt_count(); 76 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 77 sizeof(*t) + len, 78 0, pc); 79 if (!event) 80 return; 81 t = ring_buffer_event_data(event); 82 goto record_it; 83 } 84 85 if (!bt->rchan) 86 return; 87 88 t = relay_reserve(bt->rchan, sizeof(*t) + len); 89 if (t) { 90 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 91 t->time = ktime_to_ns(ktime_get()); 92 record_it: 93 t->device = bt->dev; 94 t->action = action; 95 t->pid = pid; 96 t->cpu = cpu; 97 t->pdu_len = len; 98 memcpy((void *) t + sizeof(*t), data, len); 99 100 if (blk_tracer) 101 trace_buffer_unlock_commit(buffer, event, 0, pc); 102 } 103 } 104 105 /* 106 * Send out a notify for this process, if we haven't done so since a trace 107 * started 108 */ 109 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) 110 { 111 tsk->btrace_seq = blktrace_seq; 112 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm)); 113 } 114 115 static void trace_note_time(struct blk_trace *bt) 116 { 117 struct timespec now; 118 unsigned long flags; 119 u32 words[2]; 120 121 getnstimeofday(&now); 122 words[0] = now.tv_sec; 123 words[1] = now.tv_nsec; 124 125 local_irq_save(flags); 126 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); 127 local_irq_restore(flags); 128 } 129 130 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 131 { 132 int n; 133 va_list args; 134 unsigned long flags; 135 char *buf; 136 137 if (unlikely(bt->trace_state != Blktrace_running && 138 !blk_tracer_enabled)) 139 return; 140 141 local_irq_save(flags); 142 buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); 143 va_start(args, fmt); 144 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 145 va_end(args); 146 147 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); 148 local_irq_restore(flags); 149 } 150 EXPORT_SYMBOL_GPL(__trace_note_message); 151 152 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 153 pid_t pid) 154 { 155 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 156 return 1; 157 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 158 return 1; 159 if (bt->pid && pid != bt->pid) 160 return 1; 161 162 return 0; 163 } 164 165 /* 166 * Data direction bit lookup 167 */ 168 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 169 BLK_TC_ACT(BLK_TC_WRITE) }; 170 171 /* The ilog2() calls fall out because they're constant */ 172 #define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \ 173 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name)) 174 175 /* 176 * The worker for the various blk_add_trace*() types. Fills out a 177 * blk_io_trace structure and places it in a per-cpu subbuffer. 178 */ 179 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 180 int rw, u32 what, int error, int pdu_len, void *pdu_data) 181 { 182 struct task_struct *tsk = current; 183 struct ring_buffer_event *event = NULL; 184 struct ring_buffer *buffer = NULL; 185 struct blk_io_trace *t; 186 unsigned long flags = 0; 187 unsigned long *sequence; 188 pid_t pid; 189 int cpu, pc = 0; 190 bool blk_tracer = blk_tracer_enabled; 191 192 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 193 return; 194 195 what |= ddir_act[rw & WRITE]; 196 what |= MASK_TC_BIT(rw, BARRIER); 197 what |= MASK_TC_BIT(rw, SYNCIO); 198 what |= MASK_TC_BIT(rw, AHEAD); 199 what |= MASK_TC_BIT(rw, META); 200 what |= MASK_TC_BIT(rw, DISCARD); 201 202 pid = tsk->pid; 203 if (act_log_check(bt, what, sector, pid)) 204 return; 205 cpu = raw_smp_processor_id(); 206 207 if (blk_tracer) { 208 tracing_record_cmdline(current); 209 210 buffer = blk_tr->buffer; 211 pc = preempt_count(); 212 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 213 sizeof(*t) + pdu_len, 214 0, pc); 215 if (!event) 216 return; 217 t = ring_buffer_event_data(event); 218 goto record_it; 219 } 220 221 /* 222 * A word about the locking here - we disable interrupts to reserve 223 * some space in the relay per-cpu buffer, to prevent an irq 224 * from coming in and stepping on our toes. 225 */ 226 local_irq_save(flags); 227 228 if (unlikely(tsk->btrace_seq != blktrace_seq)) 229 trace_note_tsk(bt, tsk); 230 231 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 232 if (t) { 233 sequence = per_cpu_ptr(bt->sequence, cpu); 234 235 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 236 t->sequence = ++(*sequence); 237 t->time = ktime_to_ns(ktime_get()); 238 record_it: 239 /* 240 * These two are not needed in ftrace as they are in the 241 * generic trace_entry, filled by tracing_generic_entry_update, 242 * but for the trace_event->bin() synthesizer benefit we do it 243 * here too. 244 */ 245 t->cpu = cpu; 246 t->pid = pid; 247 248 t->sector = sector; 249 t->bytes = bytes; 250 t->action = what; 251 t->device = bt->dev; 252 t->error = error; 253 t->pdu_len = pdu_len; 254 255 if (pdu_len) 256 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 257 258 if (blk_tracer) { 259 trace_buffer_unlock_commit(buffer, event, 0, pc); 260 return; 261 } 262 } 263 264 local_irq_restore(flags); 265 } 266 267 static struct dentry *blk_tree_root; 268 static DEFINE_MUTEX(blk_tree_mutex); 269 270 static void blk_trace_free(struct blk_trace *bt) 271 { 272 debugfs_remove(bt->msg_file); 273 debugfs_remove(bt->dropped_file); 274 relay_close(bt->rchan); 275 debugfs_remove(bt->dir); 276 free_percpu(bt->sequence); 277 free_percpu(bt->msg_data); 278 kfree(bt); 279 } 280 281 static void blk_trace_cleanup(struct blk_trace *bt) 282 { 283 blk_trace_free(bt); 284 if (atomic_dec_and_test(&blk_probes_ref)) 285 blk_unregister_tracepoints(); 286 } 287 288 int blk_trace_remove(struct request_queue *q) 289 { 290 struct blk_trace *bt; 291 292 bt = xchg(&q->blk_trace, NULL); 293 if (!bt) 294 return -EINVAL; 295 296 if (bt->trace_state != Blktrace_running) 297 blk_trace_cleanup(bt); 298 299 return 0; 300 } 301 EXPORT_SYMBOL_GPL(blk_trace_remove); 302 303 static int blk_dropped_open(struct inode *inode, struct file *filp) 304 { 305 filp->private_data = inode->i_private; 306 307 return 0; 308 } 309 310 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 311 size_t count, loff_t *ppos) 312 { 313 struct blk_trace *bt = filp->private_data; 314 char buf[16]; 315 316 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 317 318 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 319 } 320 321 static const struct file_operations blk_dropped_fops = { 322 .owner = THIS_MODULE, 323 .open = blk_dropped_open, 324 .read = blk_dropped_read, 325 }; 326 327 static int blk_msg_open(struct inode *inode, struct file *filp) 328 { 329 filp->private_data = inode->i_private; 330 331 return 0; 332 } 333 334 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 335 size_t count, loff_t *ppos) 336 { 337 char *msg; 338 struct blk_trace *bt; 339 340 if (count >= BLK_TN_MAX_MSG) 341 return -EINVAL; 342 343 msg = kmalloc(count + 1, GFP_KERNEL); 344 if (msg == NULL) 345 return -ENOMEM; 346 347 if (copy_from_user(msg, buffer, count)) { 348 kfree(msg); 349 return -EFAULT; 350 } 351 352 msg[count] = '\0'; 353 bt = filp->private_data; 354 __trace_note_message(bt, "%s", msg); 355 kfree(msg); 356 357 return count; 358 } 359 360 static const struct file_operations blk_msg_fops = { 361 .owner = THIS_MODULE, 362 .open = blk_msg_open, 363 .write = blk_msg_write, 364 }; 365 366 /* 367 * Keep track of how many times we encountered a full subbuffer, to aid 368 * the user space app in telling how many lost events there were. 369 */ 370 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 371 void *prev_subbuf, size_t prev_padding) 372 { 373 struct blk_trace *bt; 374 375 if (!relay_buf_full(buf)) 376 return 1; 377 378 bt = buf->chan->private_data; 379 atomic_inc(&bt->dropped); 380 return 0; 381 } 382 383 static int blk_remove_buf_file_callback(struct dentry *dentry) 384 { 385 debugfs_remove(dentry); 386 387 return 0; 388 } 389 390 static struct dentry *blk_create_buf_file_callback(const char *filename, 391 struct dentry *parent, 392 int mode, 393 struct rchan_buf *buf, 394 int *is_global) 395 { 396 return debugfs_create_file(filename, mode, parent, buf, 397 &relay_file_operations); 398 } 399 400 static struct rchan_callbacks blk_relay_callbacks = { 401 .subbuf_start = blk_subbuf_start_callback, 402 .create_buf_file = blk_create_buf_file_callback, 403 .remove_buf_file = blk_remove_buf_file_callback, 404 }; 405 406 static void blk_trace_setup_lba(struct blk_trace *bt, 407 struct block_device *bdev) 408 { 409 struct hd_struct *part = NULL; 410 411 if (bdev) 412 part = bdev->bd_part; 413 414 if (part) { 415 bt->start_lba = part->start_sect; 416 bt->end_lba = part->start_sect + part->nr_sects; 417 } else { 418 bt->start_lba = 0; 419 bt->end_lba = -1ULL; 420 } 421 } 422 423 /* 424 * Setup everything required to start tracing 425 */ 426 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 427 struct block_device *bdev, 428 struct blk_user_trace_setup *buts) 429 { 430 struct blk_trace *old_bt, *bt = NULL; 431 struct dentry *dir = NULL; 432 int ret, i; 433 434 if (!buts->buf_size || !buts->buf_nr) 435 return -EINVAL; 436 437 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 438 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 439 440 /* 441 * some device names have larger paths - convert the slashes 442 * to underscores for this to work as expected 443 */ 444 for (i = 0; i < strlen(buts->name); i++) 445 if (buts->name[i] == '/') 446 buts->name[i] = '_'; 447 448 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 449 if (!bt) 450 return -ENOMEM; 451 452 ret = -ENOMEM; 453 bt->sequence = alloc_percpu(unsigned long); 454 if (!bt->sequence) 455 goto err; 456 457 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 458 if (!bt->msg_data) 459 goto err; 460 461 ret = -ENOENT; 462 463 mutex_lock(&blk_tree_mutex); 464 if (!blk_tree_root) { 465 blk_tree_root = debugfs_create_dir("block", NULL); 466 if (!blk_tree_root) { 467 mutex_unlock(&blk_tree_mutex); 468 goto err; 469 } 470 } 471 mutex_unlock(&blk_tree_mutex); 472 473 dir = debugfs_create_dir(buts->name, blk_tree_root); 474 475 if (!dir) 476 goto err; 477 478 bt->dir = dir; 479 bt->dev = dev; 480 atomic_set(&bt->dropped, 0); 481 482 ret = -EIO; 483 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 484 &blk_dropped_fops); 485 if (!bt->dropped_file) 486 goto err; 487 488 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 489 if (!bt->msg_file) 490 goto err; 491 492 bt->rchan = relay_open("trace", dir, buts->buf_size, 493 buts->buf_nr, &blk_relay_callbacks, bt); 494 if (!bt->rchan) 495 goto err; 496 497 bt->act_mask = buts->act_mask; 498 if (!bt->act_mask) 499 bt->act_mask = (u16) -1; 500 501 blk_trace_setup_lba(bt, bdev); 502 503 /* overwrite with user settings */ 504 if (buts->start_lba) 505 bt->start_lba = buts->start_lba; 506 if (buts->end_lba) 507 bt->end_lba = buts->end_lba; 508 509 bt->pid = buts->pid; 510 bt->trace_state = Blktrace_setup; 511 512 ret = -EBUSY; 513 old_bt = xchg(&q->blk_trace, bt); 514 if (old_bt) { 515 (void) xchg(&q->blk_trace, old_bt); 516 goto err; 517 } 518 519 if (atomic_inc_return(&blk_probes_ref) == 1) 520 blk_register_tracepoints(); 521 522 return 0; 523 err: 524 blk_trace_free(bt); 525 return ret; 526 } 527 528 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 529 struct block_device *bdev, 530 char __user *arg) 531 { 532 struct blk_user_trace_setup buts; 533 int ret; 534 535 ret = copy_from_user(&buts, arg, sizeof(buts)); 536 if (ret) 537 return -EFAULT; 538 539 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 540 if (ret) 541 return ret; 542 543 if (copy_to_user(arg, &buts, sizeof(buts))) 544 return -EFAULT; 545 546 return 0; 547 } 548 EXPORT_SYMBOL_GPL(blk_trace_setup); 549 550 int blk_trace_startstop(struct request_queue *q, int start) 551 { 552 int ret; 553 struct blk_trace *bt = q->blk_trace; 554 555 if (bt == NULL) 556 return -EINVAL; 557 558 /* 559 * For starting a trace, we can transition from a setup or stopped 560 * trace. For stopping a trace, the state must be running 561 */ 562 ret = -EINVAL; 563 if (start) { 564 if (bt->trace_state == Blktrace_setup || 565 bt->trace_state == Blktrace_stopped) { 566 blktrace_seq++; 567 smp_mb(); 568 bt->trace_state = Blktrace_running; 569 570 trace_note_time(bt); 571 ret = 0; 572 } 573 } else { 574 if (bt->trace_state == Blktrace_running) { 575 bt->trace_state = Blktrace_stopped; 576 relay_flush(bt->rchan); 577 ret = 0; 578 } 579 } 580 581 return ret; 582 } 583 EXPORT_SYMBOL_GPL(blk_trace_startstop); 584 585 /** 586 * blk_trace_ioctl: - handle the ioctls associated with tracing 587 * @bdev: the block device 588 * @cmd: the ioctl cmd 589 * @arg: the argument data, if any 590 * 591 **/ 592 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 593 { 594 struct request_queue *q; 595 int ret, start = 0; 596 char b[BDEVNAME_SIZE]; 597 598 q = bdev_get_queue(bdev); 599 if (!q) 600 return -ENXIO; 601 602 mutex_lock(&bdev->bd_mutex); 603 604 switch (cmd) { 605 case BLKTRACESETUP: 606 bdevname(bdev, b); 607 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 608 break; 609 case BLKTRACESTART: 610 start = 1; 611 case BLKTRACESTOP: 612 ret = blk_trace_startstop(q, start); 613 break; 614 case BLKTRACETEARDOWN: 615 ret = blk_trace_remove(q); 616 break; 617 default: 618 ret = -ENOTTY; 619 break; 620 } 621 622 mutex_unlock(&bdev->bd_mutex); 623 return ret; 624 } 625 626 /** 627 * blk_trace_shutdown: - stop and cleanup trace structures 628 * @q: the request queue associated with the device 629 * 630 **/ 631 void blk_trace_shutdown(struct request_queue *q) 632 { 633 if (q->blk_trace) { 634 blk_trace_startstop(q, 0); 635 blk_trace_remove(q); 636 } 637 } 638 639 /* 640 * blktrace probes 641 */ 642 643 /** 644 * blk_add_trace_rq - Add a trace for a request oriented action 645 * @q: queue the io is for 646 * @rq: the source request 647 * @what: the action 648 * 649 * Description: 650 * Records an action against a request. Will log the bio offset + size. 651 * 652 **/ 653 static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 654 u32 what) 655 { 656 struct blk_trace *bt = q->blk_trace; 657 int rw = rq->cmd_flags & 0x03; 658 659 if (likely(!bt)) 660 return; 661 662 if (blk_discard_rq(rq)) 663 rw |= (1 << BIO_RW_DISCARD); 664 665 if (blk_pc_request(rq)) { 666 what |= BLK_TC_ACT(BLK_TC_PC); 667 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw, 668 what, rq->errors, rq->cmd_len, rq->cmd); 669 } else { 670 what |= BLK_TC_ACT(BLK_TC_FS); 671 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw, 672 what, rq->errors, 0, NULL); 673 } 674 } 675 676 static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq) 677 { 678 blk_add_trace_rq(q, rq, BLK_TA_ABORT); 679 } 680 681 static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq) 682 { 683 blk_add_trace_rq(q, rq, BLK_TA_INSERT); 684 } 685 686 static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq) 687 { 688 blk_add_trace_rq(q, rq, BLK_TA_ISSUE); 689 } 690 691 static void blk_add_trace_rq_requeue(struct request_queue *q, 692 struct request *rq) 693 { 694 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); 695 } 696 697 static void blk_add_trace_rq_complete(struct request_queue *q, 698 struct request *rq) 699 { 700 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE); 701 } 702 703 /** 704 * blk_add_trace_bio - Add a trace for a bio oriented action 705 * @q: queue the io is for 706 * @bio: the source bio 707 * @what: the action 708 * 709 * Description: 710 * Records an action against a bio. Will log the bio offset + size. 711 * 712 **/ 713 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 714 u32 what) 715 { 716 struct blk_trace *bt = q->blk_trace; 717 718 if (likely(!bt)) 719 return; 720 721 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, 722 !bio_flagged(bio, BIO_UPTODATE), 0, NULL); 723 } 724 725 static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio) 726 { 727 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE); 728 } 729 730 static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio) 731 { 732 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE); 733 } 734 735 static void blk_add_trace_bio_backmerge(struct request_queue *q, 736 struct bio *bio) 737 { 738 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE); 739 } 740 741 static void blk_add_trace_bio_frontmerge(struct request_queue *q, 742 struct bio *bio) 743 { 744 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE); 745 } 746 747 static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio) 748 { 749 blk_add_trace_bio(q, bio, BLK_TA_QUEUE); 750 } 751 752 static void blk_add_trace_getrq(struct request_queue *q, 753 struct bio *bio, int rw) 754 { 755 if (bio) 756 blk_add_trace_bio(q, bio, BLK_TA_GETRQ); 757 else { 758 struct blk_trace *bt = q->blk_trace; 759 760 if (bt) 761 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); 762 } 763 } 764 765 766 static void blk_add_trace_sleeprq(struct request_queue *q, 767 struct bio *bio, int rw) 768 { 769 if (bio) 770 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ); 771 else { 772 struct blk_trace *bt = q->blk_trace; 773 774 if (bt) 775 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 776 0, 0, NULL); 777 } 778 } 779 780 static void blk_add_trace_plug(struct request_queue *q) 781 { 782 struct blk_trace *bt = q->blk_trace; 783 784 if (bt) 785 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 786 } 787 788 static void blk_add_trace_unplug_io(struct request_queue *q) 789 { 790 struct blk_trace *bt = q->blk_trace; 791 792 if (bt) { 793 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 794 __be64 rpdu = cpu_to_be64(pdu); 795 796 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0, 797 sizeof(rpdu), &rpdu); 798 } 799 } 800 801 static void blk_add_trace_unplug_timer(struct request_queue *q) 802 { 803 struct blk_trace *bt = q->blk_trace; 804 805 if (bt) { 806 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 807 __be64 rpdu = cpu_to_be64(pdu); 808 809 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0, 810 sizeof(rpdu), &rpdu); 811 } 812 } 813 814 static void blk_add_trace_split(struct request_queue *q, struct bio *bio, 815 unsigned int pdu) 816 { 817 struct blk_trace *bt = q->blk_trace; 818 819 if (bt) { 820 __be64 rpdu = cpu_to_be64(pdu); 821 822 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 823 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE), 824 sizeof(rpdu), &rpdu); 825 } 826 } 827 828 /** 829 * blk_add_trace_remap - Add a trace for a remap operation 830 * @q: queue the io is for 831 * @bio: the source bio 832 * @dev: target device 833 * @from: source sector 834 * 835 * Description: 836 * Device mapper or raid target sometimes need to split a bio because 837 * it spans a stripe (or similar). Add a trace for that action. 838 * 839 **/ 840 static void blk_add_trace_remap(struct request_queue *q, struct bio *bio, 841 dev_t dev, sector_t from) 842 { 843 struct blk_trace *bt = q->blk_trace; 844 struct blk_io_trace_remap r; 845 846 if (likely(!bt)) 847 return; 848 849 r.device_from = cpu_to_be32(dev); 850 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 851 r.sector_from = cpu_to_be64(from); 852 853 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 854 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), 855 sizeof(r), &r); 856 } 857 858 /** 859 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 860 * @q: queue the io is for 861 * @rq: the source request 862 * @dev: target device 863 * @from: source sector 864 * 865 * Description: 866 * Device mapper remaps request to other devices. 867 * Add a trace for that action. 868 * 869 **/ 870 static void blk_add_trace_rq_remap(struct request_queue *q, 871 struct request *rq, dev_t dev, 872 sector_t from) 873 { 874 struct blk_trace *bt = q->blk_trace; 875 struct blk_io_trace_remap r; 876 877 if (likely(!bt)) 878 return; 879 880 r.device_from = cpu_to_be32(dev); 881 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 882 r.sector_from = cpu_to_be64(from); 883 884 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 885 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors, 886 sizeof(r), &r); 887 } 888 889 /** 890 * blk_add_driver_data - Add binary message with driver-specific data 891 * @q: queue the io is for 892 * @rq: io request 893 * @data: driver-specific data 894 * @len: length of driver-specific data 895 * 896 * Description: 897 * Some drivers might want to write driver-specific data per request. 898 * 899 **/ 900 void blk_add_driver_data(struct request_queue *q, 901 struct request *rq, 902 void *data, size_t len) 903 { 904 struct blk_trace *bt = q->blk_trace; 905 906 if (likely(!bt)) 907 return; 908 909 if (blk_pc_request(rq)) 910 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 911 BLK_TA_DRV_DATA, rq->errors, len, data); 912 else 913 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 914 BLK_TA_DRV_DATA, rq->errors, len, data); 915 } 916 EXPORT_SYMBOL_GPL(blk_add_driver_data); 917 918 static void blk_register_tracepoints(void) 919 { 920 int ret; 921 922 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort); 923 WARN_ON(ret); 924 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert); 925 WARN_ON(ret); 926 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue); 927 WARN_ON(ret); 928 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue); 929 WARN_ON(ret); 930 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete); 931 WARN_ON(ret); 932 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce); 933 WARN_ON(ret); 934 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete); 935 WARN_ON(ret); 936 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge); 937 WARN_ON(ret); 938 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge); 939 WARN_ON(ret); 940 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue); 941 WARN_ON(ret); 942 ret = register_trace_block_getrq(blk_add_trace_getrq); 943 WARN_ON(ret); 944 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq); 945 WARN_ON(ret); 946 ret = register_trace_block_plug(blk_add_trace_plug); 947 WARN_ON(ret); 948 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer); 949 WARN_ON(ret); 950 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io); 951 WARN_ON(ret); 952 ret = register_trace_block_split(blk_add_trace_split); 953 WARN_ON(ret); 954 ret = register_trace_block_remap(blk_add_trace_remap); 955 WARN_ON(ret); 956 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap); 957 WARN_ON(ret); 958 } 959 960 static void blk_unregister_tracepoints(void) 961 { 962 unregister_trace_block_rq_remap(blk_add_trace_rq_remap); 963 unregister_trace_block_remap(blk_add_trace_remap); 964 unregister_trace_block_split(blk_add_trace_split); 965 unregister_trace_block_unplug_io(blk_add_trace_unplug_io); 966 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer); 967 unregister_trace_block_plug(blk_add_trace_plug); 968 unregister_trace_block_sleeprq(blk_add_trace_sleeprq); 969 unregister_trace_block_getrq(blk_add_trace_getrq); 970 unregister_trace_block_bio_queue(blk_add_trace_bio_queue); 971 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge); 972 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge); 973 unregister_trace_block_bio_complete(blk_add_trace_bio_complete); 974 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce); 975 unregister_trace_block_rq_complete(blk_add_trace_rq_complete); 976 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue); 977 unregister_trace_block_rq_issue(blk_add_trace_rq_issue); 978 unregister_trace_block_rq_insert(blk_add_trace_rq_insert); 979 unregister_trace_block_rq_abort(blk_add_trace_rq_abort); 980 981 tracepoint_synchronize_unregister(); 982 } 983 984 /* 985 * struct blk_io_tracer formatting routines 986 */ 987 988 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 989 { 990 int i = 0; 991 int tc = t->action >> BLK_TC_SHIFT; 992 993 if (t->action == BLK_TN_MESSAGE) { 994 rwbs[i++] = 'N'; 995 goto out; 996 } 997 998 if (tc & BLK_TC_DISCARD) 999 rwbs[i++] = 'D'; 1000 else if (tc & BLK_TC_WRITE) 1001 rwbs[i++] = 'W'; 1002 else if (t->bytes) 1003 rwbs[i++] = 'R'; 1004 else 1005 rwbs[i++] = 'N'; 1006 1007 if (tc & BLK_TC_AHEAD) 1008 rwbs[i++] = 'A'; 1009 if (tc & BLK_TC_BARRIER) 1010 rwbs[i++] = 'B'; 1011 if (tc & BLK_TC_SYNC) 1012 rwbs[i++] = 'S'; 1013 if (tc & BLK_TC_META) 1014 rwbs[i++] = 'M'; 1015 out: 1016 rwbs[i] = '\0'; 1017 } 1018 1019 static inline 1020 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1021 { 1022 return (const struct blk_io_trace *)ent; 1023 } 1024 1025 static inline const void *pdu_start(const struct trace_entry *ent) 1026 { 1027 return te_blk_io_trace(ent) + 1; 1028 } 1029 1030 static inline u32 t_action(const struct trace_entry *ent) 1031 { 1032 return te_blk_io_trace(ent)->action; 1033 } 1034 1035 static inline u32 t_bytes(const struct trace_entry *ent) 1036 { 1037 return te_blk_io_trace(ent)->bytes; 1038 } 1039 1040 static inline u32 t_sec(const struct trace_entry *ent) 1041 { 1042 return te_blk_io_trace(ent)->bytes >> 9; 1043 } 1044 1045 static inline unsigned long long t_sector(const struct trace_entry *ent) 1046 { 1047 return te_blk_io_trace(ent)->sector; 1048 } 1049 1050 static inline __u16 t_error(const struct trace_entry *ent) 1051 { 1052 return te_blk_io_trace(ent)->error; 1053 } 1054 1055 static __u64 get_pdu_int(const struct trace_entry *ent) 1056 { 1057 const __u64 *val = pdu_start(ent); 1058 return be64_to_cpu(*val); 1059 } 1060 1061 static void get_pdu_remap(const struct trace_entry *ent, 1062 struct blk_io_trace_remap *r) 1063 { 1064 const struct blk_io_trace_remap *__r = pdu_start(ent); 1065 __u64 sector_from = __r->sector_from; 1066 1067 r->device_from = be32_to_cpu(__r->device_from); 1068 r->device_to = be32_to_cpu(__r->device_to); 1069 r->sector_from = be64_to_cpu(sector_from); 1070 } 1071 1072 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1073 1074 static int blk_log_action_classic(struct trace_iterator *iter, const char *act) 1075 { 1076 char rwbs[6]; 1077 unsigned long long ts = iter->ts; 1078 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1079 unsigned secs = (unsigned long)ts; 1080 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1081 1082 fill_rwbs(rwbs, t); 1083 1084 return trace_seq_printf(&iter->seq, 1085 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1086 MAJOR(t->device), MINOR(t->device), iter->cpu, 1087 secs, nsec_rem, iter->ent->pid, act, rwbs); 1088 } 1089 1090 static int blk_log_action(struct trace_iterator *iter, const char *act) 1091 { 1092 char rwbs[6]; 1093 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1094 1095 fill_rwbs(rwbs, t); 1096 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1097 MAJOR(t->device), MINOR(t->device), act, rwbs); 1098 } 1099 1100 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1101 { 1102 const unsigned char *pdu_buf; 1103 int pdu_len; 1104 int i, end, ret; 1105 1106 pdu_buf = pdu_start(ent); 1107 pdu_len = te_blk_io_trace(ent)->pdu_len; 1108 1109 if (!pdu_len) 1110 return 1; 1111 1112 /* find the last zero that needs to be printed */ 1113 for (end = pdu_len - 1; end >= 0; end--) 1114 if (pdu_buf[end]) 1115 break; 1116 end++; 1117 1118 if (!trace_seq_putc(s, '(')) 1119 return 0; 1120 1121 for (i = 0; i < pdu_len; i++) { 1122 1123 ret = trace_seq_printf(s, "%s%02x", 1124 i == 0 ? "" : " ", pdu_buf[i]); 1125 if (!ret) 1126 return ret; 1127 1128 /* 1129 * stop when the rest is just zeroes and indicate so 1130 * with a ".." appended 1131 */ 1132 if (i == end && end != pdu_len - 1) 1133 return trace_seq_puts(s, " ..) "); 1134 } 1135 1136 return trace_seq_puts(s, ") "); 1137 } 1138 1139 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1140 { 1141 char cmd[TASK_COMM_LEN]; 1142 1143 trace_find_cmdline(ent->pid, cmd); 1144 1145 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1146 int ret; 1147 1148 ret = trace_seq_printf(s, "%u ", t_bytes(ent)); 1149 if (!ret) 1150 return 0; 1151 ret = blk_log_dump_pdu(s, ent); 1152 if (!ret) 1153 return 0; 1154 return trace_seq_printf(s, "[%s]\n", cmd); 1155 } else { 1156 if (t_sec(ent)) 1157 return trace_seq_printf(s, "%llu + %u [%s]\n", 1158 t_sector(ent), t_sec(ent), cmd); 1159 return trace_seq_printf(s, "[%s]\n", cmd); 1160 } 1161 } 1162 1163 static int blk_log_with_error(struct trace_seq *s, 1164 const struct trace_entry *ent) 1165 { 1166 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1167 int ret; 1168 1169 ret = blk_log_dump_pdu(s, ent); 1170 if (ret) 1171 return trace_seq_printf(s, "[%d]\n", t_error(ent)); 1172 return 0; 1173 } else { 1174 if (t_sec(ent)) 1175 return trace_seq_printf(s, "%llu + %u [%d]\n", 1176 t_sector(ent), 1177 t_sec(ent), t_error(ent)); 1178 return trace_seq_printf(s, "%llu [%d]\n", 1179 t_sector(ent), t_error(ent)); 1180 } 1181 } 1182 1183 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1184 { 1185 struct blk_io_trace_remap r = { .device_from = 0, }; 1186 1187 get_pdu_remap(ent, &r); 1188 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1189 t_sector(ent), t_sec(ent), 1190 MAJOR(r.device_from), MINOR(r.device_from), 1191 (unsigned long long)r.sector_from); 1192 } 1193 1194 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1195 { 1196 char cmd[TASK_COMM_LEN]; 1197 1198 trace_find_cmdline(ent->pid, cmd); 1199 1200 return trace_seq_printf(s, "[%s]\n", cmd); 1201 } 1202 1203 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1204 { 1205 char cmd[TASK_COMM_LEN]; 1206 1207 trace_find_cmdline(ent->pid, cmd); 1208 1209 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1210 } 1211 1212 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1213 { 1214 char cmd[TASK_COMM_LEN]; 1215 1216 trace_find_cmdline(ent->pid, cmd); 1217 1218 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1219 get_pdu_int(ent), cmd); 1220 } 1221 1222 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1223 { 1224 int ret; 1225 const struct blk_io_trace *t = te_blk_io_trace(ent); 1226 1227 ret = trace_seq_putmem(s, t + 1, t->pdu_len); 1228 if (ret) 1229 return trace_seq_putc(s, '\n'); 1230 return ret; 1231 } 1232 1233 /* 1234 * struct tracer operations 1235 */ 1236 1237 static void blk_tracer_print_header(struct seq_file *m) 1238 { 1239 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1240 return; 1241 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1242 "# | | | | | |\n"); 1243 } 1244 1245 static void blk_tracer_start(struct trace_array *tr) 1246 { 1247 blk_tracer_enabled = true; 1248 } 1249 1250 static int blk_tracer_init(struct trace_array *tr) 1251 { 1252 blk_tr = tr; 1253 blk_tracer_start(tr); 1254 return 0; 1255 } 1256 1257 static void blk_tracer_stop(struct trace_array *tr) 1258 { 1259 blk_tracer_enabled = false; 1260 } 1261 1262 static void blk_tracer_reset(struct trace_array *tr) 1263 { 1264 blk_tracer_stop(tr); 1265 } 1266 1267 static const struct { 1268 const char *act[2]; 1269 int (*print)(struct trace_seq *s, const struct trace_entry *ent); 1270 } what2act[] = { 1271 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1272 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1273 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1274 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1275 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1276 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1277 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1278 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1279 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1280 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1281 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1282 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1283 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1284 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1285 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1286 }; 1287 1288 static enum print_line_t print_one_line(struct trace_iterator *iter, 1289 bool classic) 1290 { 1291 struct trace_seq *s = &iter->seq; 1292 const struct blk_io_trace *t; 1293 u16 what; 1294 int ret; 1295 bool long_act; 1296 blk_log_action_t *log_action; 1297 1298 t = te_blk_io_trace(iter->ent); 1299 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1300 long_act = !!(trace_flags & TRACE_ITER_VERBOSE); 1301 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1302 1303 if (t->action == BLK_TN_MESSAGE) { 1304 ret = log_action(iter, long_act ? "message" : "m"); 1305 if (ret) 1306 ret = blk_log_msg(s, iter->ent); 1307 goto out; 1308 } 1309 1310 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1311 ret = trace_seq_printf(s, "Unknown action %x\n", what); 1312 else { 1313 ret = log_action(iter, what2act[what].act[long_act]); 1314 if (ret) 1315 ret = what2act[what].print(s, iter->ent); 1316 } 1317 out: 1318 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1319 } 1320 1321 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1322 int flags) 1323 { 1324 return print_one_line(iter, false); 1325 } 1326 1327 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1328 { 1329 struct trace_seq *s = &iter->seq; 1330 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1331 const int offset = offsetof(struct blk_io_trace, sector); 1332 struct blk_io_trace old = { 1333 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1334 .time = iter->ts, 1335 }; 1336 1337 if (!trace_seq_putmem(s, &old, offset)) 1338 return 0; 1339 return trace_seq_putmem(s, &t->sector, 1340 sizeof(old) - offset + t->pdu_len); 1341 } 1342 1343 static enum print_line_t 1344 blk_trace_event_print_binary(struct trace_iterator *iter, int flags) 1345 { 1346 return blk_trace_synthesize_old_trace(iter) ? 1347 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1348 } 1349 1350 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1351 { 1352 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1353 return TRACE_TYPE_UNHANDLED; 1354 1355 return print_one_line(iter, true); 1356 } 1357 1358 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set) 1359 { 1360 /* don't output context-info for blk_classic output */ 1361 if (bit == TRACE_BLK_OPT_CLASSIC) { 1362 if (set) 1363 trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1364 else 1365 trace_flags |= TRACE_ITER_CONTEXT_INFO; 1366 } 1367 return 0; 1368 } 1369 1370 static struct tracer blk_tracer __read_mostly = { 1371 .name = "blk", 1372 .init = blk_tracer_init, 1373 .reset = blk_tracer_reset, 1374 .start = blk_tracer_start, 1375 .stop = blk_tracer_stop, 1376 .print_header = blk_tracer_print_header, 1377 .print_line = blk_tracer_print_line, 1378 .flags = &blk_tracer_flags, 1379 .set_flag = blk_tracer_set_flag, 1380 }; 1381 1382 static struct trace_event trace_blk_event = { 1383 .type = TRACE_BLK, 1384 .trace = blk_trace_event_print, 1385 .binary = blk_trace_event_print_binary, 1386 }; 1387 1388 static int __init init_blk_tracer(void) 1389 { 1390 if (!register_ftrace_event(&trace_blk_event)) { 1391 pr_warning("Warning: could not register block events\n"); 1392 return 1; 1393 } 1394 1395 if (register_tracer(&blk_tracer) != 0) { 1396 pr_warning("Warning: could not register the block tracer\n"); 1397 unregister_ftrace_event(&trace_blk_event); 1398 return 1; 1399 } 1400 1401 return 0; 1402 } 1403 1404 device_initcall(init_blk_tracer); 1405 1406 static int blk_trace_remove_queue(struct request_queue *q) 1407 { 1408 struct blk_trace *bt; 1409 1410 bt = xchg(&q->blk_trace, NULL); 1411 if (bt == NULL) 1412 return -EINVAL; 1413 1414 if (atomic_dec_and_test(&blk_probes_ref)) 1415 blk_unregister_tracepoints(); 1416 1417 blk_trace_free(bt); 1418 return 0; 1419 } 1420 1421 /* 1422 * Setup everything required to start tracing 1423 */ 1424 static int blk_trace_setup_queue(struct request_queue *q, 1425 struct block_device *bdev) 1426 { 1427 struct blk_trace *old_bt, *bt = NULL; 1428 int ret = -ENOMEM; 1429 1430 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1431 if (!bt) 1432 return -ENOMEM; 1433 1434 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1435 if (!bt->msg_data) 1436 goto free_bt; 1437 1438 bt->dev = bdev->bd_dev; 1439 bt->act_mask = (u16)-1; 1440 1441 blk_trace_setup_lba(bt, bdev); 1442 1443 old_bt = xchg(&q->blk_trace, bt); 1444 if (old_bt != NULL) { 1445 (void)xchg(&q->blk_trace, old_bt); 1446 ret = -EBUSY; 1447 goto free_bt; 1448 } 1449 1450 if (atomic_inc_return(&blk_probes_ref) == 1) 1451 blk_register_tracepoints(); 1452 return 0; 1453 1454 free_bt: 1455 blk_trace_free(bt); 1456 return ret; 1457 } 1458 1459 /* 1460 * sysfs interface to enable and configure tracing 1461 */ 1462 1463 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1464 struct device_attribute *attr, 1465 char *buf); 1466 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1467 struct device_attribute *attr, 1468 const char *buf, size_t count); 1469 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1470 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1471 sysfs_blk_trace_attr_show, \ 1472 sysfs_blk_trace_attr_store) 1473 1474 static BLK_TRACE_DEVICE_ATTR(enable); 1475 static BLK_TRACE_DEVICE_ATTR(act_mask); 1476 static BLK_TRACE_DEVICE_ATTR(pid); 1477 static BLK_TRACE_DEVICE_ATTR(start_lba); 1478 static BLK_TRACE_DEVICE_ATTR(end_lba); 1479 1480 static struct attribute *blk_trace_attrs[] = { 1481 &dev_attr_enable.attr, 1482 &dev_attr_act_mask.attr, 1483 &dev_attr_pid.attr, 1484 &dev_attr_start_lba.attr, 1485 &dev_attr_end_lba.attr, 1486 NULL 1487 }; 1488 1489 struct attribute_group blk_trace_attr_group = { 1490 .name = "trace", 1491 .attrs = blk_trace_attrs, 1492 }; 1493 1494 static const struct { 1495 int mask; 1496 const char *str; 1497 } mask_maps[] = { 1498 { BLK_TC_READ, "read" }, 1499 { BLK_TC_WRITE, "write" }, 1500 { BLK_TC_BARRIER, "barrier" }, 1501 { BLK_TC_SYNC, "sync" }, 1502 { BLK_TC_QUEUE, "queue" }, 1503 { BLK_TC_REQUEUE, "requeue" }, 1504 { BLK_TC_ISSUE, "issue" }, 1505 { BLK_TC_COMPLETE, "complete" }, 1506 { BLK_TC_FS, "fs" }, 1507 { BLK_TC_PC, "pc" }, 1508 { BLK_TC_AHEAD, "ahead" }, 1509 { BLK_TC_META, "meta" }, 1510 { BLK_TC_DISCARD, "discard" }, 1511 { BLK_TC_DRV_DATA, "drv_data" }, 1512 }; 1513 1514 static int blk_trace_str2mask(const char *str) 1515 { 1516 int i; 1517 int mask = 0; 1518 char *buf, *s, *token; 1519 1520 buf = kstrdup(str, GFP_KERNEL); 1521 if (buf == NULL) 1522 return -ENOMEM; 1523 s = strstrip(buf); 1524 1525 while (1) { 1526 token = strsep(&s, ","); 1527 if (token == NULL) 1528 break; 1529 1530 if (*token == '\0') 1531 continue; 1532 1533 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1534 if (strcasecmp(token, mask_maps[i].str) == 0) { 1535 mask |= mask_maps[i].mask; 1536 break; 1537 } 1538 } 1539 if (i == ARRAY_SIZE(mask_maps)) { 1540 mask = -EINVAL; 1541 break; 1542 } 1543 } 1544 kfree(buf); 1545 1546 return mask; 1547 } 1548 1549 static ssize_t blk_trace_mask2str(char *buf, int mask) 1550 { 1551 int i; 1552 char *p = buf; 1553 1554 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1555 if (mask & mask_maps[i].mask) { 1556 p += sprintf(p, "%s%s", 1557 (p == buf) ? "" : ",", mask_maps[i].str); 1558 } 1559 } 1560 *p++ = '\n'; 1561 1562 return p - buf; 1563 } 1564 1565 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1566 { 1567 if (bdev->bd_disk == NULL) 1568 return NULL; 1569 1570 return bdev_get_queue(bdev); 1571 } 1572 1573 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1574 struct device_attribute *attr, 1575 char *buf) 1576 { 1577 struct hd_struct *p = dev_to_part(dev); 1578 struct request_queue *q; 1579 struct block_device *bdev; 1580 ssize_t ret = -ENXIO; 1581 1582 lock_kernel(); 1583 bdev = bdget(part_devt(p)); 1584 if (bdev == NULL) 1585 goto out_unlock_kernel; 1586 1587 q = blk_trace_get_queue(bdev); 1588 if (q == NULL) 1589 goto out_bdput; 1590 1591 mutex_lock(&bdev->bd_mutex); 1592 1593 if (attr == &dev_attr_enable) { 1594 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1595 goto out_unlock_bdev; 1596 } 1597 1598 if (q->blk_trace == NULL) 1599 ret = sprintf(buf, "disabled\n"); 1600 else if (attr == &dev_attr_act_mask) 1601 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1602 else if (attr == &dev_attr_pid) 1603 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1604 else if (attr == &dev_attr_start_lba) 1605 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1606 else if (attr == &dev_attr_end_lba) 1607 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1608 1609 out_unlock_bdev: 1610 mutex_unlock(&bdev->bd_mutex); 1611 out_bdput: 1612 bdput(bdev); 1613 out_unlock_kernel: 1614 unlock_kernel(); 1615 return ret; 1616 } 1617 1618 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1619 struct device_attribute *attr, 1620 const char *buf, size_t count) 1621 { 1622 struct block_device *bdev; 1623 struct request_queue *q; 1624 struct hd_struct *p; 1625 u64 value; 1626 ssize_t ret = -EINVAL; 1627 1628 if (count == 0) 1629 goto out; 1630 1631 if (attr == &dev_attr_act_mask) { 1632 if (sscanf(buf, "%llx", &value) != 1) { 1633 /* Assume it is a list of trace category names */ 1634 ret = blk_trace_str2mask(buf); 1635 if (ret < 0) 1636 goto out; 1637 value = ret; 1638 } 1639 } else if (sscanf(buf, "%llu", &value) != 1) 1640 goto out; 1641 1642 ret = -ENXIO; 1643 1644 lock_kernel(); 1645 p = dev_to_part(dev); 1646 bdev = bdget(part_devt(p)); 1647 if (bdev == NULL) 1648 goto out_unlock_kernel; 1649 1650 q = blk_trace_get_queue(bdev); 1651 if (q == NULL) 1652 goto out_bdput; 1653 1654 mutex_lock(&bdev->bd_mutex); 1655 1656 if (attr == &dev_attr_enable) { 1657 if (value) 1658 ret = blk_trace_setup_queue(q, bdev); 1659 else 1660 ret = blk_trace_remove_queue(q); 1661 goto out_unlock_bdev; 1662 } 1663 1664 ret = 0; 1665 if (q->blk_trace == NULL) 1666 ret = blk_trace_setup_queue(q, bdev); 1667 1668 if (ret == 0) { 1669 if (attr == &dev_attr_act_mask) 1670 q->blk_trace->act_mask = value; 1671 else if (attr == &dev_attr_pid) 1672 q->blk_trace->pid = value; 1673 else if (attr == &dev_attr_start_lba) 1674 q->blk_trace->start_lba = value; 1675 else if (attr == &dev_attr_end_lba) 1676 q->blk_trace->end_lba = value; 1677 } 1678 1679 out_unlock_bdev: 1680 mutex_unlock(&bdev->bd_mutex); 1681 out_bdput: 1682 bdput(bdev); 1683 out_unlock_kernel: 1684 unlock_kernel(); 1685 out: 1686 return ret ? ret : count; 1687 } 1688 1689 int blk_trace_init_sysfs(struct device *dev) 1690 { 1691 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1692 } 1693 1694 void blk_trace_remove_sysfs(struct device *dev) 1695 { 1696 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1697 } 1698 1699 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1700 1701 #ifdef CONFIG_EVENT_TRACING 1702 1703 void blk_dump_cmd(char *buf, struct request *rq) 1704 { 1705 int i, end; 1706 int len = rq->cmd_len; 1707 unsigned char *cmd = rq->cmd; 1708 1709 if (!blk_pc_request(rq)) { 1710 buf[0] = '\0'; 1711 return; 1712 } 1713 1714 for (end = len - 1; end >= 0; end--) 1715 if (cmd[end]) 1716 break; 1717 end++; 1718 1719 for (i = 0; i < len; i++) { 1720 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1721 if (i == end && end != len - 1) { 1722 sprintf(buf, " .."); 1723 break; 1724 } 1725 } 1726 } 1727 1728 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) 1729 { 1730 int i = 0; 1731 1732 if (rw & WRITE) 1733 rwbs[i++] = 'W'; 1734 else if (rw & 1 << BIO_RW_DISCARD) 1735 rwbs[i++] = 'D'; 1736 else if (bytes) 1737 rwbs[i++] = 'R'; 1738 else 1739 rwbs[i++] = 'N'; 1740 1741 if (rw & 1 << BIO_RW_AHEAD) 1742 rwbs[i++] = 'A'; 1743 if (rw & 1 << BIO_RW_BARRIER) 1744 rwbs[i++] = 'B'; 1745 if (rw & 1 << BIO_RW_SYNCIO) 1746 rwbs[i++] = 'S'; 1747 if (rw & 1 << BIO_RW_META) 1748 rwbs[i++] = 'M'; 1749 1750 rwbs[i] = '\0'; 1751 } 1752 1753 void blk_fill_rwbs_rq(char *rwbs, struct request *rq) 1754 { 1755 int rw = rq->cmd_flags & 0x03; 1756 int bytes; 1757 1758 if (blk_discard_rq(rq)) 1759 rw |= (1 << BIO_RW_DISCARD); 1760 1761 bytes = blk_rq_bytes(rq); 1762 1763 blk_fill_rwbs(rwbs, rw, bytes); 1764 } 1765 1766 #endif /* CONFIG_EVENT_TRACING */ 1767 1768