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