1 /* 2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 16 * 17 */ 18 #include <linux/kernel.h> 19 #include <linux/blkdev.h> 20 #include <linux/blktrace_api.h> 21 #include <linux/percpu.h> 22 #include <linux/init.h> 23 #include <linux/mutex.h> 24 #include <linux/slab.h> 25 #include <linux/debugfs.h> 26 #include <linux/export.h> 27 #include <linux/time.h> 28 #include <linux/uaccess.h> 29 30 #include <trace/events/block.h> 31 32 #include "trace_output.h" 33 34 #ifdef CONFIG_BLK_DEV_IO_TRACE 35 36 static unsigned int blktrace_seq __read_mostly = 1; 37 38 static struct trace_array *blk_tr; 39 static bool blk_tracer_enabled __read_mostly; 40 41 /* Select an alternative, minimalistic output than the original one */ 42 #define TRACE_BLK_OPT_CLASSIC 0x1 43 44 static struct tracer_opt blk_tracer_opts[] = { 45 /* Default disable the minimalistic output */ 46 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 47 { } 48 }; 49 50 static struct tracer_flags blk_tracer_flags = { 51 .val = 0, 52 .opts = blk_tracer_opts, 53 }; 54 55 /* Global reference count of probes */ 56 static atomic_t blk_probes_ref = ATOMIC_INIT(0); 57 58 static void blk_register_tracepoints(void); 59 static void blk_unregister_tracepoints(void); 60 61 /* 62 * Send out a notify message. 63 */ 64 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 65 const void *data, size_t len) 66 { 67 struct blk_io_trace *t; 68 struct ring_buffer_event *event = NULL; 69 struct ring_buffer *buffer = NULL; 70 int pc = 0; 71 int cpu = smp_processor_id(); 72 bool blk_tracer = blk_tracer_enabled; 73 74 if (blk_tracer) { 75 buffer = blk_tr->buffer; 76 pc = preempt_count(); 77 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 78 sizeof(*t) + len, 79 0, pc); 80 if (!event) 81 return; 82 t = ring_buffer_event_data(event); 83 goto record_it; 84 } 85 86 if (!bt->rchan) 87 return; 88 89 t = relay_reserve(bt->rchan, sizeof(*t) + len); 90 if (t) { 91 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 92 t->time = ktime_to_ns(ktime_get()); 93 record_it: 94 t->device = bt->dev; 95 t->action = action; 96 t->pid = pid; 97 t->cpu = cpu; 98 t->pdu_len = len; 99 memcpy((void *) t + sizeof(*t), data, len); 100 101 if (blk_tracer) 102 trace_buffer_unlock_commit(buffer, event, 0, pc); 103 } 104 } 105 106 /* 107 * Send out a notify for this process, if we haven't done so since a trace 108 * started 109 */ 110 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) 111 { 112 tsk->btrace_seq = blktrace_seq; 113 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm)); 114 } 115 116 static void trace_note_time(struct blk_trace *bt) 117 { 118 struct timespec now; 119 unsigned long flags; 120 u32 words[2]; 121 122 getnstimeofday(&now); 123 words[0] = now.tv_sec; 124 words[1] = now.tv_nsec; 125 126 local_irq_save(flags); 127 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); 128 local_irq_restore(flags); 129 } 130 131 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 132 { 133 int n; 134 va_list args; 135 unsigned long flags; 136 char *buf; 137 138 if (unlikely(bt->trace_state != Blktrace_running && 139 !blk_tracer_enabled)) 140 return; 141 142 /* 143 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note 144 * message to the trace. 145 */ 146 if (!(bt->act_mask & BLK_TC_NOTIFY)) 147 return; 148 149 local_irq_save(flags); 150 buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); 151 va_start(args, fmt); 152 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 153 va_end(args); 154 155 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); 156 local_irq_restore(flags); 157 } 158 EXPORT_SYMBOL_GPL(__trace_note_message); 159 160 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 161 pid_t pid) 162 { 163 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 164 return 1; 165 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 166 return 1; 167 if (bt->pid && pid != bt->pid) 168 return 1; 169 170 return 0; 171 } 172 173 /* 174 * Data direction bit lookup 175 */ 176 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 177 BLK_TC_ACT(BLK_TC_WRITE) }; 178 179 #define BLK_TC_RAHEAD BLK_TC_AHEAD 180 181 /* The ilog2() calls fall out because they're constant */ 182 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \ 183 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name)) 184 185 /* 186 * The worker for the various blk_add_trace*() types. Fills out a 187 * blk_io_trace structure and places it in a per-cpu subbuffer. 188 */ 189 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 190 int rw, u32 what, int error, int pdu_len, void *pdu_data) 191 { 192 struct task_struct *tsk = current; 193 struct ring_buffer_event *event = NULL; 194 struct ring_buffer *buffer = NULL; 195 struct blk_io_trace *t; 196 unsigned long flags = 0; 197 unsigned long *sequence; 198 pid_t pid; 199 int cpu, pc = 0; 200 bool blk_tracer = blk_tracer_enabled; 201 202 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 203 return; 204 205 what |= ddir_act[rw & WRITE]; 206 what |= MASK_TC_BIT(rw, SYNC); 207 what |= MASK_TC_BIT(rw, RAHEAD); 208 what |= MASK_TC_BIT(rw, META); 209 what |= MASK_TC_BIT(rw, DISCARD); 210 what |= MASK_TC_BIT(rw, FLUSH); 211 what |= MASK_TC_BIT(rw, FUA); 212 213 pid = tsk->pid; 214 if (act_log_check(bt, what, sector, pid)) 215 return; 216 cpu = raw_smp_processor_id(); 217 218 if (blk_tracer) { 219 tracing_record_cmdline(current); 220 221 buffer = blk_tr->buffer; 222 pc = preempt_count(); 223 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 224 sizeof(*t) + pdu_len, 225 0, pc); 226 if (!event) 227 return; 228 t = ring_buffer_event_data(event); 229 goto record_it; 230 } 231 232 /* 233 * A word about the locking here - we disable interrupts to reserve 234 * some space in the relay per-cpu buffer, to prevent an irq 235 * from coming in and stepping on our toes. 236 */ 237 local_irq_save(flags); 238 239 if (unlikely(tsk->btrace_seq != blktrace_seq)) 240 trace_note_tsk(bt, tsk); 241 242 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 243 if (t) { 244 sequence = per_cpu_ptr(bt->sequence, cpu); 245 246 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 247 t->sequence = ++(*sequence); 248 t->time = ktime_to_ns(ktime_get()); 249 record_it: 250 /* 251 * These two are not needed in ftrace as they are in the 252 * generic trace_entry, filled by tracing_generic_entry_update, 253 * but for the trace_event->bin() synthesizer benefit we do it 254 * here too. 255 */ 256 t->cpu = cpu; 257 t->pid = pid; 258 259 t->sector = sector; 260 t->bytes = bytes; 261 t->action = what; 262 t->device = bt->dev; 263 t->error = error; 264 t->pdu_len = pdu_len; 265 266 if (pdu_len) 267 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 268 269 if (blk_tracer) { 270 trace_buffer_unlock_commit(buffer, event, 0, pc); 271 return; 272 } 273 } 274 275 local_irq_restore(flags); 276 } 277 278 static struct dentry *blk_tree_root; 279 static DEFINE_MUTEX(blk_tree_mutex); 280 281 static void blk_trace_free(struct blk_trace *bt) 282 { 283 debugfs_remove(bt->msg_file); 284 debugfs_remove(bt->dropped_file); 285 relay_close(bt->rchan); 286 debugfs_remove(bt->dir); 287 free_percpu(bt->sequence); 288 free_percpu(bt->msg_data); 289 kfree(bt); 290 } 291 292 static void blk_trace_cleanup(struct blk_trace *bt) 293 { 294 blk_trace_free(bt); 295 if (atomic_dec_and_test(&blk_probes_ref)) 296 blk_unregister_tracepoints(); 297 } 298 299 int blk_trace_remove(struct request_queue *q) 300 { 301 struct blk_trace *bt; 302 303 bt = xchg(&q->blk_trace, NULL); 304 if (!bt) 305 return -EINVAL; 306 307 if (bt->trace_state != Blktrace_running) 308 blk_trace_cleanup(bt); 309 310 return 0; 311 } 312 EXPORT_SYMBOL_GPL(blk_trace_remove); 313 314 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 315 size_t count, loff_t *ppos) 316 { 317 struct blk_trace *bt = filp->private_data; 318 char buf[16]; 319 320 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 321 322 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 323 } 324 325 static const struct file_operations blk_dropped_fops = { 326 .owner = THIS_MODULE, 327 .open = simple_open, 328 .read = blk_dropped_read, 329 .llseek = default_llseek, 330 }; 331 332 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 333 size_t count, loff_t *ppos) 334 { 335 char *msg; 336 struct blk_trace *bt; 337 338 if (count >= BLK_TN_MAX_MSG) 339 return -EINVAL; 340 341 msg = kmalloc(count + 1, GFP_KERNEL); 342 if (msg == NULL) 343 return -ENOMEM; 344 345 if (copy_from_user(msg, buffer, count)) { 346 kfree(msg); 347 return -EFAULT; 348 } 349 350 msg[count] = '\0'; 351 bt = filp->private_data; 352 __trace_note_message(bt, "%s", msg); 353 kfree(msg); 354 355 return count; 356 } 357 358 static const struct file_operations blk_msg_fops = { 359 .owner = THIS_MODULE, 360 .open = simple_open, 361 .write = blk_msg_write, 362 .llseek = noop_llseek, 363 }; 364 365 /* 366 * Keep track of how many times we encountered a full subbuffer, to aid 367 * the user space app in telling how many lost events there were. 368 */ 369 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 370 void *prev_subbuf, size_t prev_padding) 371 { 372 struct blk_trace *bt; 373 374 if (!relay_buf_full(buf)) 375 return 1; 376 377 bt = buf->chan->private_data; 378 atomic_inc(&bt->dropped); 379 return 0; 380 } 381 382 static int blk_remove_buf_file_callback(struct dentry *dentry) 383 { 384 debugfs_remove(dentry); 385 386 return 0; 387 } 388 389 static struct dentry *blk_create_buf_file_callback(const char *filename, 390 struct dentry *parent, 391 umode_t mode, 392 struct rchan_buf *buf, 393 int *is_global) 394 { 395 return debugfs_create_file(filename, mode, parent, buf, 396 &relay_file_operations); 397 } 398 399 static struct rchan_callbacks blk_relay_callbacks = { 400 .subbuf_start = blk_subbuf_start_callback, 401 .create_buf_file = blk_create_buf_file_callback, 402 .remove_buf_file = blk_remove_buf_file_callback, 403 }; 404 405 static void blk_trace_setup_lba(struct blk_trace *bt, 406 struct block_device *bdev) 407 { 408 struct hd_struct *part = NULL; 409 410 if (bdev) 411 part = bdev->bd_part; 412 413 if (part) { 414 bt->start_lba = part->start_sect; 415 bt->end_lba = part->start_sect + part->nr_sects; 416 } else { 417 bt->start_lba = 0; 418 bt->end_lba = -1ULL; 419 } 420 } 421 422 /* 423 * Setup everything required to start tracing 424 */ 425 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 426 struct block_device *bdev, 427 struct blk_user_trace_setup *buts) 428 { 429 struct blk_trace *old_bt, *bt = NULL; 430 struct dentry *dir = NULL; 431 int ret, i; 432 433 if (!buts->buf_size || !buts->buf_nr) 434 return -EINVAL; 435 436 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 437 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 438 439 /* 440 * some device names have larger paths - convert the slashes 441 * to underscores for this to work as expected 442 */ 443 for (i = 0; i < strlen(buts->name); i++) 444 if (buts->name[i] == '/') 445 buts->name[i] = '_'; 446 447 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 448 if (!bt) 449 return -ENOMEM; 450 451 ret = -ENOMEM; 452 bt->sequence = alloc_percpu(unsigned long); 453 if (!bt->sequence) 454 goto err; 455 456 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 457 if (!bt->msg_data) 458 goto err; 459 460 ret = -ENOENT; 461 462 mutex_lock(&blk_tree_mutex); 463 if (!blk_tree_root) { 464 blk_tree_root = debugfs_create_dir("block", NULL); 465 if (!blk_tree_root) { 466 mutex_unlock(&blk_tree_mutex); 467 goto err; 468 } 469 } 470 mutex_unlock(&blk_tree_mutex); 471 472 dir = debugfs_create_dir(buts->name, blk_tree_root); 473 474 if (!dir) 475 goto err; 476 477 bt->dir = dir; 478 bt->dev = dev; 479 atomic_set(&bt->dropped, 0); 480 481 ret = -EIO; 482 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 483 &blk_dropped_fops); 484 if (!bt->dropped_file) 485 goto err; 486 487 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 488 if (!bt->msg_file) 489 goto err; 490 491 bt->rchan = relay_open("trace", dir, buts->buf_size, 492 buts->buf_nr, &blk_relay_callbacks, bt); 493 if (!bt->rchan) 494 goto err; 495 496 bt->act_mask = buts->act_mask; 497 if (!bt->act_mask) 498 bt->act_mask = (u16) -1; 499 500 blk_trace_setup_lba(bt, bdev); 501 502 /* overwrite with user settings */ 503 if (buts->start_lba) 504 bt->start_lba = buts->start_lba; 505 if (buts->end_lba) 506 bt->end_lba = buts->end_lba; 507 508 bt->pid = buts->pid; 509 bt->trace_state = Blktrace_setup; 510 511 ret = -EBUSY; 512 old_bt = xchg(&q->blk_trace, bt); 513 if (old_bt) { 514 (void) xchg(&q->blk_trace, old_bt); 515 goto err; 516 } 517 518 if (atomic_inc_return(&blk_probes_ref) == 1) 519 blk_register_tracepoints(); 520 521 return 0; 522 err: 523 blk_trace_free(bt); 524 return ret; 525 } 526 527 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 528 struct block_device *bdev, 529 char __user *arg) 530 { 531 struct blk_user_trace_setup buts; 532 int ret; 533 534 ret = copy_from_user(&buts, arg, sizeof(buts)); 535 if (ret) 536 return -EFAULT; 537 538 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 539 if (ret) 540 return ret; 541 542 if (copy_to_user(arg, &buts, sizeof(buts))) { 543 blk_trace_remove(q); 544 return -EFAULT; 545 } 546 return 0; 547 } 548 EXPORT_SYMBOL_GPL(blk_trace_setup); 549 550 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 551 static int compat_blk_trace_setup(struct request_queue *q, char *name, 552 dev_t dev, struct block_device *bdev, 553 char __user *arg) 554 { 555 struct blk_user_trace_setup buts; 556 struct compat_blk_user_trace_setup cbuts; 557 int ret; 558 559 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 560 return -EFAULT; 561 562 buts = (struct blk_user_trace_setup) { 563 .act_mask = cbuts.act_mask, 564 .buf_size = cbuts.buf_size, 565 .buf_nr = cbuts.buf_nr, 566 .start_lba = cbuts.start_lba, 567 .end_lba = cbuts.end_lba, 568 .pid = cbuts.pid, 569 }; 570 memcpy(&buts.name, &cbuts.name, 32); 571 572 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 573 if (ret) 574 return ret; 575 576 if (copy_to_user(arg, &buts.name, 32)) { 577 blk_trace_remove(q); 578 return -EFAULT; 579 } 580 581 return 0; 582 } 583 #endif 584 585 int blk_trace_startstop(struct request_queue *q, int start) 586 { 587 int ret; 588 struct blk_trace *bt = q->blk_trace; 589 590 if (bt == NULL) 591 return -EINVAL; 592 593 /* 594 * For starting a trace, we can transition from a setup or stopped 595 * trace. For stopping a trace, the state must be running 596 */ 597 ret = -EINVAL; 598 if (start) { 599 if (bt->trace_state == Blktrace_setup || 600 bt->trace_state == Blktrace_stopped) { 601 blktrace_seq++; 602 smp_mb(); 603 bt->trace_state = Blktrace_running; 604 605 trace_note_time(bt); 606 ret = 0; 607 } 608 } else { 609 if (bt->trace_state == Blktrace_running) { 610 bt->trace_state = Blktrace_stopped; 611 relay_flush(bt->rchan); 612 ret = 0; 613 } 614 } 615 616 return ret; 617 } 618 EXPORT_SYMBOL_GPL(blk_trace_startstop); 619 620 /** 621 * blk_trace_ioctl: - handle the ioctls associated with tracing 622 * @bdev: the block device 623 * @cmd: the ioctl cmd 624 * @arg: the argument data, if any 625 * 626 **/ 627 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 628 { 629 struct request_queue *q; 630 int ret, start = 0; 631 char b[BDEVNAME_SIZE]; 632 633 q = bdev_get_queue(bdev); 634 if (!q) 635 return -ENXIO; 636 637 mutex_lock(&bdev->bd_mutex); 638 639 switch (cmd) { 640 case BLKTRACESETUP: 641 bdevname(bdev, b); 642 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 643 break; 644 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 645 case BLKTRACESETUP32: 646 bdevname(bdev, b); 647 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 648 break; 649 #endif 650 case BLKTRACESTART: 651 start = 1; 652 case BLKTRACESTOP: 653 ret = blk_trace_startstop(q, start); 654 break; 655 case BLKTRACETEARDOWN: 656 ret = blk_trace_remove(q); 657 break; 658 default: 659 ret = -ENOTTY; 660 break; 661 } 662 663 mutex_unlock(&bdev->bd_mutex); 664 return ret; 665 } 666 667 /** 668 * blk_trace_shutdown: - stop and cleanup trace structures 669 * @q: the request queue associated with the device 670 * 671 **/ 672 void blk_trace_shutdown(struct request_queue *q) 673 { 674 if (q->blk_trace) { 675 blk_trace_startstop(q, 0); 676 blk_trace_remove(q); 677 } 678 } 679 680 /* 681 * blktrace probes 682 */ 683 684 /** 685 * blk_add_trace_rq - Add a trace for a request oriented action 686 * @q: queue the io is for 687 * @rq: the source request 688 * @what: the action 689 * 690 * Description: 691 * Records an action against a request. Will log the bio offset + size. 692 * 693 **/ 694 static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 695 u32 what) 696 { 697 struct blk_trace *bt = q->blk_trace; 698 699 if (likely(!bt)) 700 return; 701 702 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { 703 what |= BLK_TC_ACT(BLK_TC_PC); 704 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags, 705 what, rq->errors, rq->cmd_len, rq->cmd); 706 } else { 707 what |= BLK_TC_ACT(BLK_TC_FS); 708 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 709 rq->cmd_flags, what, rq->errors, 0, NULL); 710 } 711 } 712 713 static void blk_add_trace_rq_abort(void *ignore, 714 struct request_queue *q, struct request *rq) 715 { 716 blk_add_trace_rq(q, rq, BLK_TA_ABORT); 717 } 718 719 static void blk_add_trace_rq_insert(void *ignore, 720 struct request_queue *q, struct request *rq) 721 { 722 blk_add_trace_rq(q, rq, BLK_TA_INSERT); 723 } 724 725 static void blk_add_trace_rq_issue(void *ignore, 726 struct request_queue *q, struct request *rq) 727 { 728 blk_add_trace_rq(q, rq, BLK_TA_ISSUE); 729 } 730 731 static void blk_add_trace_rq_requeue(void *ignore, 732 struct request_queue *q, 733 struct request *rq) 734 { 735 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); 736 } 737 738 static void blk_add_trace_rq_complete(void *ignore, 739 struct request_queue *q, 740 struct request *rq) 741 { 742 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE); 743 } 744 745 /** 746 * blk_add_trace_bio - Add a trace for a bio oriented action 747 * @q: queue the io is for 748 * @bio: the source bio 749 * @what: the action 750 * @error: error, if any 751 * 752 * Description: 753 * Records an action against a bio. Will log the bio offset + size. 754 * 755 **/ 756 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 757 u32 what, int error) 758 { 759 struct blk_trace *bt = q->blk_trace; 760 761 if (likely(!bt)) 762 return; 763 764 if (!error && !bio_flagged(bio, BIO_UPTODATE)) 765 error = EIO; 766 767 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, 768 error, 0, NULL); 769 } 770 771 static void blk_add_trace_bio_bounce(void *ignore, 772 struct request_queue *q, struct bio *bio) 773 { 774 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0); 775 } 776 777 static void blk_add_trace_bio_complete(void *ignore, 778 struct request_queue *q, struct bio *bio, 779 int error) 780 { 781 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error); 782 } 783 784 static void blk_add_trace_bio_backmerge(void *ignore, 785 struct request_queue *q, 786 struct bio *bio) 787 { 788 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0); 789 } 790 791 static void blk_add_trace_bio_frontmerge(void *ignore, 792 struct request_queue *q, 793 struct bio *bio) 794 { 795 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0); 796 } 797 798 static void blk_add_trace_bio_queue(void *ignore, 799 struct request_queue *q, struct bio *bio) 800 { 801 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0); 802 } 803 804 static void blk_add_trace_getrq(void *ignore, 805 struct request_queue *q, 806 struct bio *bio, int rw) 807 { 808 if (bio) 809 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0); 810 else { 811 struct blk_trace *bt = q->blk_trace; 812 813 if (bt) 814 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); 815 } 816 } 817 818 819 static void blk_add_trace_sleeprq(void *ignore, 820 struct request_queue *q, 821 struct bio *bio, int rw) 822 { 823 if (bio) 824 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0); 825 else { 826 struct blk_trace *bt = q->blk_trace; 827 828 if (bt) 829 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 830 0, 0, NULL); 831 } 832 } 833 834 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 835 { 836 struct blk_trace *bt = q->blk_trace; 837 838 if (bt) 839 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 840 } 841 842 static void blk_add_trace_unplug(void *ignore, struct request_queue *q, 843 unsigned int depth, bool explicit) 844 { 845 struct blk_trace *bt = q->blk_trace; 846 847 if (bt) { 848 __be64 rpdu = cpu_to_be64(depth); 849 u32 what; 850 851 if (explicit) 852 what = BLK_TA_UNPLUG_IO; 853 else 854 what = BLK_TA_UNPLUG_TIMER; 855 856 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu); 857 } 858 } 859 860 static void blk_add_trace_split(void *ignore, 861 struct request_queue *q, struct bio *bio, 862 unsigned int pdu) 863 { 864 struct blk_trace *bt = q->blk_trace; 865 866 if (bt) { 867 __be64 rpdu = cpu_to_be64(pdu); 868 869 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 870 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE), 871 sizeof(rpdu), &rpdu); 872 } 873 } 874 875 /** 876 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation 877 * @ignore: trace callback data parameter (not used) 878 * @q: queue the io is for 879 * @bio: the source bio 880 * @dev: target device 881 * @from: source sector 882 * 883 * Description: 884 * Device mapper or raid target sometimes need to split a bio because 885 * it spans a stripe (or similar). Add a trace for that action. 886 * 887 **/ 888 static void blk_add_trace_bio_remap(void *ignore, 889 struct request_queue *q, struct bio *bio, 890 dev_t dev, sector_t from) 891 { 892 struct blk_trace *bt = q->blk_trace; 893 struct blk_io_trace_remap r; 894 895 if (likely(!bt)) 896 return; 897 898 r.device_from = cpu_to_be32(dev); 899 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 900 r.sector_from = cpu_to_be64(from); 901 902 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 903 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), 904 sizeof(r), &r); 905 } 906 907 /** 908 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 909 * @ignore: trace callback data parameter (not used) 910 * @q: queue the io is for 911 * @rq: the source request 912 * @dev: target device 913 * @from: source sector 914 * 915 * Description: 916 * Device mapper remaps request to other devices. 917 * Add a trace for that action. 918 * 919 **/ 920 static void blk_add_trace_rq_remap(void *ignore, 921 struct request_queue *q, 922 struct request *rq, dev_t dev, 923 sector_t from) 924 { 925 struct blk_trace *bt = q->blk_trace; 926 struct blk_io_trace_remap r; 927 928 if (likely(!bt)) 929 return; 930 931 r.device_from = cpu_to_be32(dev); 932 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 933 r.sector_from = cpu_to_be64(from); 934 935 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 936 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors, 937 sizeof(r), &r); 938 } 939 940 /** 941 * blk_add_driver_data - Add binary message with driver-specific data 942 * @q: queue the io is for 943 * @rq: io request 944 * @data: driver-specific data 945 * @len: length of driver-specific data 946 * 947 * Description: 948 * Some drivers might want to write driver-specific data per request. 949 * 950 **/ 951 void blk_add_driver_data(struct request_queue *q, 952 struct request *rq, 953 void *data, size_t len) 954 { 955 struct blk_trace *bt = q->blk_trace; 956 957 if (likely(!bt)) 958 return; 959 960 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) 961 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 962 BLK_TA_DRV_DATA, rq->errors, len, data); 963 else 964 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 965 BLK_TA_DRV_DATA, rq->errors, len, data); 966 } 967 EXPORT_SYMBOL_GPL(blk_add_driver_data); 968 969 static void blk_register_tracepoints(void) 970 { 971 int ret; 972 973 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 974 WARN_ON(ret); 975 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 976 WARN_ON(ret); 977 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 978 WARN_ON(ret); 979 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 980 WARN_ON(ret); 981 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 982 WARN_ON(ret); 983 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 984 WARN_ON(ret); 985 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 986 WARN_ON(ret); 987 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 988 WARN_ON(ret); 989 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 990 WARN_ON(ret); 991 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 992 WARN_ON(ret); 993 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 994 WARN_ON(ret); 995 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 996 WARN_ON(ret); 997 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 998 WARN_ON(ret); 999 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL); 1000 WARN_ON(ret); 1001 ret = register_trace_block_split(blk_add_trace_split, NULL); 1002 WARN_ON(ret); 1003 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1004 WARN_ON(ret); 1005 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1006 WARN_ON(ret); 1007 } 1008 1009 static void blk_unregister_tracepoints(void) 1010 { 1011 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1012 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1013 unregister_trace_block_split(blk_add_trace_split, NULL); 1014 unregister_trace_block_unplug(blk_add_trace_unplug, NULL); 1015 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1016 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1017 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1018 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1019 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1020 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1021 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1022 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1023 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1024 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1025 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1026 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1027 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 1028 1029 tracepoint_synchronize_unregister(); 1030 } 1031 1032 /* 1033 * struct blk_io_tracer formatting routines 1034 */ 1035 1036 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1037 { 1038 int i = 0; 1039 int tc = t->action >> BLK_TC_SHIFT; 1040 1041 if (t->action == BLK_TN_MESSAGE) { 1042 rwbs[i++] = 'N'; 1043 goto out; 1044 } 1045 1046 if (tc & BLK_TC_FLUSH) 1047 rwbs[i++] = 'F'; 1048 1049 if (tc & BLK_TC_DISCARD) 1050 rwbs[i++] = 'D'; 1051 else if (tc & BLK_TC_WRITE) 1052 rwbs[i++] = 'W'; 1053 else if (t->bytes) 1054 rwbs[i++] = 'R'; 1055 else 1056 rwbs[i++] = 'N'; 1057 1058 if (tc & BLK_TC_FUA) 1059 rwbs[i++] = 'F'; 1060 if (tc & BLK_TC_AHEAD) 1061 rwbs[i++] = 'A'; 1062 if (tc & BLK_TC_SYNC) 1063 rwbs[i++] = 'S'; 1064 if (tc & BLK_TC_META) 1065 rwbs[i++] = 'M'; 1066 out: 1067 rwbs[i] = '\0'; 1068 } 1069 1070 static inline 1071 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1072 { 1073 return (const struct blk_io_trace *)ent; 1074 } 1075 1076 static inline const void *pdu_start(const struct trace_entry *ent) 1077 { 1078 return te_blk_io_trace(ent) + 1; 1079 } 1080 1081 static inline u32 t_action(const struct trace_entry *ent) 1082 { 1083 return te_blk_io_trace(ent)->action; 1084 } 1085 1086 static inline u32 t_bytes(const struct trace_entry *ent) 1087 { 1088 return te_blk_io_trace(ent)->bytes; 1089 } 1090 1091 static inline u32 t_sec(const struct trace_entry *ent) 1092 { 1093 return te_blk_io_trace(ent)->bytes >> 9; 1094 } 1095 1096 static inline unsigned long long t_sector(const struct trace_entry *ent) 1097 { 1098 return te_blk_io_trace(ent)->sector; 1099 } 1100 1101 static inline __u16 t_error(const struct trace_entry *ent) 1102 { 1103 return te_blk_io_trace(ent)->error; 1104 } 1105 1106 static __u64 get_pdu_int(const struct trace_entry *ent) 1107 { 1108 const __u64 *val = pdu_start(ent); 1109 return be64_to_cpu(*val); 1110 } 1111 1112 static void get_pdu_remap(const struct trace_entry *ent, 1113 struct blk_io_trace_remap *r) 1114 { 1115 const struct blk_io_trace_remap *__r = pdu_start(ent); 1116 __u64 sector_from = __r->sector_from; 1117 1118 r->device_from = be32_to_cpu(__r->device_from); 1119 r->device_to = be32_to_cpu(__r->device_to); 1120 r->sector_from = be64_to_cpu(sector_from); 1121 } 1122 1123 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1124 1125 static int blk_log_action_classic(struct trace_iterator *iter, const char *act) 1126 { 1127 char rwbs[RWBS_LEN]; 1128 unsigned long long ts = iter->ts; 1129 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1130 unsigned secs = (unsigned long)ts; 1131 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1132 1133 fill_rwbs(rwbs, t); 1134 1135 return trace_seq_printf(&iter->seq, 1136 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1137 MAJOR(t->device), MINOR(t->device), iter->cpu, 1138 secs, nsec_rem, iter->ent->pid, act, rwbs); 1139 } 1140 1141 static int blk_log_action(struct trace_iterator *iter, const char *act) 1142 { 1143 char rwbs[RWBS_LEN]; 1144 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1145 1146 fill_rwbs(rwbs, t); 1147 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1148 MAJOR(t->device), MINOR(t->device), act, rwbs); 1149 } 1150 1151 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1152 { 1153 const unsigned char *pdu_buf; 1154 int pdu_len; 1155 int i, end, ret; 1156 1157 pdu_buf = pdu_start(ent); 1158 pdu_len = te_blk_io_trace(ent)->pdu_len; 1159 1160 if (!pdu_len) 1161 return 1; 1162 1163 /* find the last zero that needs to be printed */ 1164 for (end = pdu_len - 1; end >= 0; end--) 1165 if (pdu_buf[end]) 1166 break; 1167 end++; 1168 1169 if (!trace_seq_putc(s, '(')) 1170 return 0; 1171 1172 for (i = 0; i < pdu_len; i++) { 1173 1174 ret = trace_seq_printf(s, "%s%02x", 1175 i == 0 ? "" : " ", pdu_buf[i]); 1176 if (!ret) 1177 return ret; 1178 1179 /* 1180 * stop when the rest is just zeroes and indicate so 1181 * with a ".." appended 1182 */ 1183 if (i == end && end != pdu_len - 1) 1184 return trace_seq_puts(s, " ..) "); 1185 } 1186 1187 return trace_seq_puts(s, ") "); 1188 } 1189 1190 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1191 { 1192 char cmd[TASK_COMM_LEN]; 1193 1194 trace_find_cmdline(ent->pid, cmd); 1195 1196 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1197 int ret; 1198 1199 ret = trace_seq_printf(s, "%u ", t_bytes(ent)); 1200 if (!ret) 1201 return 0; 1202 ret = blk_log_dump_pdu(s, ent); 1203 if (!ret) 1204 return 0; 1205 return trace_seq_printf(s, "[%s]\n", cmd); 1206 } else { 1207 if (t_sec(ent)) 1208 return trace_seq_printf(s, "%llu + %u [%s]\n", 1209 t_sector(ent), t_sec(ent), cmd); 1210 return trace_seq_printf(s, "[%s]\n", cmd); 1211 } 1212 } 1213 1214 static int blk_log_with_error(struct trace_seq *s, 1215 const struct trace_entry *ent) 1216 { 1217 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1218 int ret; 1219 1220 ret = blk_log_dump_pdu(s, ent); 1221 if (ret) 1222 return trace_seq_printf(s, "[%d]\n", t_error(ent)); 1223 return 0; 1224 } else { 1225 if (t_sec(ent)) 1226 return trace_seq_printf(s, "%llu + %u [%d]\n", 1227 t_sector(ent), 1228 t_sec(ent), t_error(ent)); 1229 return trace_seq_printf(s, "%llu [%d]\n", 1230 t_sector(ent), t_error(ent)); 1231 } 1232 } 1233 1234 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1235 { 1236 struct blk_io_trace_remap r = { .device_from = 0, }; 1237 1238 get_pdu_remap(ent, &r); 1239 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1240 t_sector(ent), t_sec(ent), 1241 MAJOR(r.device_from), MINOR(r.device_from), 1242 (unsigned long long)r.sector_from); 1243 } 1244 1245 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1246 { 1247 char cmd[TASK_COMM_LEN]; 1248 1249 trace_find_cmdline(ent->pid, cmd); 1250 1251 return trace_seq_printf(s, "[%s]\n", cmd); 1252 } 1253 1254 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1255 { 1256 char cmd[TASK_COMM_LEN]; 1257 1258 trace_find_cmdline(ent->pid, cmd); 1259 1260 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1261 } 1262 1263 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1264 { 1265 char cmd[TASK_COMM_LEN]; 1266 1267 trace_find_cmdline(ent->pid, cmd); 1268 1269 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1270 get_pdu_int(ent), cmd); 1271 } 1272 1273 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1274 { 1275 int ret; 1276 const struct blk_io_trace *t = te_blk_io_trace(ent); 1277 1278 ret = trace_seq_putmem(s, t + 1, t->pdu_len); 1279 if (ret) 1280 return trace_seq_putc(s, '\n'); 1281 return ret; 1282 } 1283 1284 /* 1285 * struct tracer operations 1286 */ 1287 1288 static void blk_tracer_print_header(struct seq_file *m) 1289 { 1290 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1291 return; 1292 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1293 "# | | | | | |\n"); 1294 } 1295 1296 static void blk_tracer_start(struct trace_array *tr) 1297 { 1298 blk_tracer_enabled = true; 1299 } 1300 1301 static int blk_tracer_init(struct trace_array *tr) 1302 { 1303 blk_tr = tr; 1304 blk_tracer_start(tr); 1305 return 0; 1306 } 1307 1308 static void blk_tracer_stop(struct trace_array *tr) 1309 { 1310 blk_tracer_enabled = false; 1311 } 1312 1313 static void blk_tracer_reset(struct trace_array *tr) 1314 { 1315 blk_tracer_stop(tr); 1316 } 1317 1318 static const struct { 1319 const char *act[2]; 1320 int (*print)(struct trace_seq *s, const struct trace_entry *ent); 1321 } what2act[] = { 1322 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1323 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1324 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1325 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1326 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1327 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1328 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1329 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1330 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1331 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1332 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1333 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1334 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1335 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1336 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1337 }; 1338 1339 static enum print_line_t print_one_line(struct trace_iterator *iter, 1340 bool classic) 1341 { 1342 struct trace_seq *s = &iter->seq; 1343 const struct blk_io_trace *t; 1344 u16 what; 1345 int ret; 1346 bool long_act; 1347 blk_log_action_t *log_action; 1348 1349 t = te_blk_io_trace(iter->ent); 1350 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1351 long_act = !!(trace_flags & TRACE_ITER_VERBOSE); 1352 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1353 1354 if (t->action == BLK_TN_MESSAGE) { 1355 ret = log_action(iter, long_act ? "message" : "m"); 1356 if (ret) 1357 ret = blk_log_msg(s, iter->ent); 1358 goto out; 1359 } 1360 1361 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1362 ret = trace_seq_printf(s, "Unknown action %x\n", what); 1363 else { 1364 ret = log_action(iter, what2act[what].act[long_act]); 1365 if (ret) 1366 ret = what2act[what].print(s, iter->ent); 1367 } 1368 out: 1369 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1370 } 1371 1372 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1373 int flags, struct trace_event *event) 1374 { 1375 return print_one_line(iter, false); 1376 } 1377 1378 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1379 { 1380 struct trace_seq *s = &iter->seq; 1381 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1382 const int offset = offsetof(struct blk_io_trace, sector); 1383 struct blk_io_trace old = { 1384 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1385 .time = iter->ts, 1386 }; 1387 1388 if (!trace_seq_putmem(s, &old, offset)) 1389 return 0; 1390 return trace_seq_putmem(s, &t->sector, 1391 sizeof(old) - offset + t->pdu_len); 1392 } 1393 1394 static enum print_line_t 1395 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1396 struct trace_event *event) 1397 { 1398 return blk_trace_synthesize_old_trace(iter) ? 1399 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1400 } 1401 1402 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1403 { 1404 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1405 return TRACE_TYPE_UNHANDLED; 1406 1407 return print_one_line(iter, true); 1408 } 1409 1410 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set) 1411 { 1412 /* don't output context-info for blk_classic output */ 1413 if (bit == TRACE_BLK_OPT_CLASSIC) { 1414 if (set) 1415 trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1416 else 1417 trace_flags |= TRACE_ITER_CONTEXT_INFO; 1418 } 1419 return 0; 1420 } 1421 1422 static struct tracer blk_tracer __read_mostly = { 1423 .name = "blk", 1424 .init = blk_tracer_init, 1425 .reset = blk_tracer_reset, 1426 .start = blk_tracer_start, 1427 .stop = blk_tracer_stop, 1428 .print_header = blk_tracer_print_header, 1429 .print_line = blk_tracer_print_line, 1430 .flags = &blk_tracer_flags, 1431 .set_flag = blk_tracer_set_flag, 1432 }; 1433 1434 static struct trace_event_functions trace_blk_event_funcs = { 1435 .trace = blk_trace_event_print, 1436 .binary = blk_trace_event_print_binary, 1437 }; 1438 1439 static struct trace_event trace_blk_event = { 1440 .type = TRACE_BLK, 1441 .funcs = &trace_blk_event_funcs, 1442 }; 1443 1444 static int __init init_blk_tracer(void) 1445 { 1446 if (!register_ftrace_event(&trace_blk_event)) { 1447 pr_warning("Warning: could not register block events\n"); 1448 return 1; 1449 } 1450 1451 if (register_tracer(&blk_tracer) != 0) { 1452 pr_warning("Warning: could not register the block tracer\n"); 1453 unregister_ftrace_event(&trace_blk_event); 1454 return 1; 1455 } 1456 1457 return 0; 1458 } 1459 1460 device_initcall(init_blk_tracer); 1461 1462 static int blk_trace_remove_queue(struct request_queue *q) 1463 { 1464 struct blk_trace *bt; 1465 1466 bt = xchg(&q->blk_trace, NULL); 1467 if (bt == NULL) 1468 return -EINVAL; 1469 1470 if (atomic_dec_and_test(&blk_probes_ref)) 1471 blk_unregister_tracepoints(); 1472 1473 blk_trace_free(bt); 1474 return 0; 1475 } 1476 1477 /* 1478 * Setup everything required to start tracing 1479 */ 1480 static int blk_trace_setup_queue(struct request_queue *q, 1481 struct block_device *bdev) 1482 { 1483 struct blk_trace *old_bt, *bt = NULL; 1484 int ret = -ENOMEM; 1485 1486 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1487 if (!bt) 1488 return -ENOMEM; 1489 1490 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1491 if (!bt->msg_data) 1492 goto free_bt; 1493 1494 bt->dev = bdev->bd_dev; 1495 bt->act_mask = (u16)-1; 1496 1497 blk_trace_setup_lba(bt, bdev); 1498 1499 old_bt = xchg(&q->blk_trace, bt); 1500 if (old_bt != NULL) { 1501 (void)xchg(&q->blk_trace, old_bt); 1502 ret = -EBUSY; 1503 goto free_bt; 1504 } 1505 1506 if (atomic_inc_return(&blk_probes_ref) == 1) 1507 blk_register_tracepoints(); 1508 return 0; 1509 1510 free_bt: 1511 blk_trace_free(bt); 1512 return ret; 1513 } 1514 1515 /* 1516 * sysfs interface to enable and configure tracing 1517 */ 1518 1519 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1520 struct device_attribute *attr, 1521 char *buf); 1522 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1523 struct device_attribute *attr, 1524 const char *buf, size_t count); 1525 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1526 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1527 sysfs_blk_trace_attr_show, \ 1528 sysfs_blk_trace_attr_store) 1529 1530 static BLK_TRACE_DEVICE_ATTR(enable); 1531 static BLK_TRACE_DEVICE_ATTR(act_mask); 1532 static BLK_TRACE_DEVICE_ATTR(pid); 1533 static BLK_TRACE_DEVICE_ATTR(start_lba); 1534 static BLK_TRACE_DEVICE_ATTR(end_lba); 1535 1536 static struct attribute *blk_trace_attrs[] = { 1537 &dev_attr_enable.attr, 1538 &dev_attr_act_mask.attr, 1539 &dev_attr_pid.attr, 1540 &dev_attr_start_lba.attr, 1541 &dev_attr_end_lba.attr, 1542 NULL 1543 }; 1544 1545 struct attribute_group blk_trace_attr_group = { 1546 .name = "trace", 1547 .attrs = blk_trace_attrs, 1548 }; 1549 1550 static const struct { 1551 int mask; 1552 const char *str; 1553 } mask_maps[] = { 1554 { BLK_TC_READ, "read" }, 1555 { BLK_TC_WRITE, "write" }, 1556 { BLK_TC_FLUSH, "flush" }, 1557 { BLK_TC_SYNC, "sync" }, 1558 { BLK_TC_QUEUE, "queue" }, 1559 { BLK_TC_REQUEUE, "requeue" }, 1560 { BLK_TC_ISSUE, "issue" }, 1561 { BLK_TC_COMPLETE, "complete" }, 1562 { BLK_TC_FS, "fs" }, 1563 { BLK_TC_PC, "pc" }, 1564 { BLK_TC_AHEAD, "ahead" }, 1565 { BLK_TC_META, "meta" }, 1566 { BLK_TC_DISCARD, "discard" }, 1567 { BLK_TC_DRV_DATA, "drv_data" }, 1568 { BLK_TC_FUA, "fua" }, 1569 }; 1570 1571 static int blk_trace_str2mask(const char *str) 1572 { 1573 int i; 1574 int mask = 0; 1575 char *buf, *s, *token; 1576 1577 buf = kstrdup(str, GFP_KERNEL); 1578 if (buf == NULL) 1579 return -ENOMEM; 1580 s = strstrip(buf); 1581 1582 while (1) { 1583 token = strsep(&s, ","); 1584 if (token == NULL) 1585 break; 1586 1587 if (*token == '\0') 1588 continue; 1589 1590 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1591 if (strcasecmp(token, mask_maps[i].str) == 0) { 1592 mask |= mask_maps[i].mask; 1593 break; 1594 } 1595 } 1596 if (i == ARRAY_SIZE(mask_maps)) { 1597 mask = -EINVAL; 1598 break; 1599 } 1600 } 1601 kfree(buf); 1602 1603 return mask; 1604 } 1605 1606 static ssize_t blk_trace_mask2str(char *buf, int mask) 1607 { 1608 int i; 1609 char *p = buf; 1610 1611 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1612 if (mask & mask_maps[i].mask) { 1613 p += sprintf(p, "%s%s", 1614 (p == buf) ? "" : ",", mask_maps[i].str); 1615 } 1616 } 1617 *p++ = '\n'; 1618 1619 return p - buf; 1620 } 1621 1622 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1623 { 1624 if (bdev->bd_disk == NULL) 1625 return NULL; 1626 1627 return bdev_get_queue(bdev); 1628 } 1629 1630 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1631 struct device_attribute *attr, 1632 char *buf) 1633 { 1634 struct hd_struct *p = dev_to_part(dev); 1635 struct request_queue *q; 1636 struct block_device *bdev; 1637 ssize_t ret = -ENXIO; 1638 1639 bdev = bdget(part_devt(p)); 1640 if (bdev == NULL) 1641 goto out; 1642 1643 q = blk_trace_get_queue(bdev); 1644 if (q == NULL) 1645 goto out_bdput; 1646 1647 mutex_lock(&bdev->bd_mutex); 1648 1649 if (attr == &dev_attr_enable) { 1650 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1651 goto out_unlock_bdev; 1652 } 1653 1654 if (q->blk_trace == NULL) 1655 ret = sprintf(buf, "disabled\n"); 1656 else if (attr == &dev_attr_act_mask) 1657 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1658 else if (attr == &dev_attr_pid) 1659 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1660 else if (attr == &dev_attr_start_lba) 1661 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1662 else if (attr == &dev_attr_end_lba) 1663 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1664 1665 out_unlock_bdev: 1666 mutex_unlock(&bdev->bd_mutex); 1667 out_bdput: 1668 bdput(bdev); 1669 out: 1670 return ret; 1671 } 1672 1673 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1674 struct device_attribute *attr, 1675 const char *buf, size_t count) 1676 { 1677 struct block_device *bdev; 1678 struct request_queue *q; 1679 struct hd_struct *p; 1680 u64 value; 1681 ssize_t ret = -EINVAL; 1682 1683 if (count == 0) 1684 goto out; 1685 1686 if (attr == &dev_attr_act_mask) { 1687 if (sscanf(buf, "%llx", &value) != 1) { 1688 /* Assume it is a list of trace category names */ 1689 ret = blk_trace_str2mask(buf); 1690 if (ret < 0) 1691 goto out; 1692 value = ret; 1693 } 1694 } else if (sscanf(buf, "%llu", &value) != 1) 1695 goto out; 1696 1697 ret = -ENXIO; 1698 1699 p = dev_to_part(dev); 1700 bdev = bdget(part_devt(p)); 1701 if (bdev == NULL) 1702 goto out; 1703 1704 q = blk_trace_get_queue(bdev); 1705 if (q == NULL) 1706 goto out_bdput; 1707 1708 mutex_lock(&bdev->bd_mutex); 1709 1710 if (attr == &dev_attr_enable) { 1711 if (value) 1712 ret = blk_trace_setup_queue(q, bdev); 1713 else 1714 ret = blk_trace_remove_queue(q); 1715 goto out_unlock_bdev; 1716 } 1717 1718 ret = 0; 1719 if (q->blk_trace == NULL) 1720 ret = blk_trace_setup_queue(q, bdev); 1721 1722 if (ret == 0) { 1723 if (attr == &dev_attr_act_mask) 1724 q->blk_trace->act_mask = value; 1725 else if (attr == &dev_attr_pid) 1726 q->blk_trace->pid = value; 1727 else if (attr == &dev_attr_start_lba) 1728 q->blk_trace->start_lba = value; 1729 else if (attr == &dev_attr_end_lba) 1730 q->blk_trace->end_lba = value; 1731 } 1732 1733 out_unlock_bdev: 1734 mutex_unlock(&bdev->bd_mutex); 1735 out_bdput: 1736 bdput(bdev); 1737 out: 1738 return ret ? ret : count; 1739 } 1740 1741 int blk_trace_init_sysfs(struct device *dev) 1742 { 1743 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1744 } 1745 1746 void blk_trace_remove_sysfs(struct device *dev) 1747 { 1748 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1749 } 1750 1751 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1752 1753 #ifdef CONFIG_EVENT_TRACING 1754 1755 void blk_dump_cmd(char *buf, struct request *rq) 1756 { 1757 int i, end; 1758 int len = rq->cmd_len; 1759 unsigned char *cmd = rq->cmd; 1760 1761 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) { 1762 buf[0] = '\0'; 1763 return; 1764 } 1765 1766 for (end = len - 1; end >= 0; end--) 1767 if (cmd[end]) 1768 break; 1769 end++; 1770 1771 for (i = 0; i < len; i++) { 1772 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1773 if (i == end && end != len - 1) { 1774 sprintf(buf, " .."); 1775 break; 1776 } 1777 } 1778 } 1779 1780 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) 1781 { 1782 int i = 0; 1783 1784 if (rw & REQ_FLUSH) 1785 rwbs[i++] = 'F'; 1786 1787 if (rw & WRITE) 1788 rwbs[i++] = 'W'; 1789 else if (rw & REQ_DISCARD) 1790 rwbs[i++] = 'D'; 1791 else if (bytes) 1792 rwbs[i++] = 'R'; 1793 else 1794 rwbs[i++] = 'N'; 1795 1796 if (rw & REQ_FUA) 1797 rwbs[i++] = 'F'; 1798 if (rw & REQ_RAHEAD) 1799 rwbs[i++] = 'A'; 1800 if (rw & REQ_SYNC) 1801 rwbs[i++] = 'S'; 1802 if (rw & REQ_META) 1803 rwbs[i++] = 'M'; 1804 if (rw & REQ_SECURE) 1805 rwbs[i++] = 'E'; 1806 1807 rwbs[i] = '\0'; 1808 } 1809 1810 #endif /* CONFIG_EVENT_TRACING */ 1811 1812