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 #include <linux/list.h> 30 31 #include <trace/events/block.h> 32 33 #include "trace_output.h" 34 35 #ifdef CONFIG_BLK_DEV_IO_TRACE 36 37 static unsigned int blktrace_seq __read_mostly = 1; 38 39 static struct trace_array *blk_tr; 40 static bool blk_tracer_enabled __read_mostly; 41 42 static LIST_HEAD(running_trace_list); 43 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock); 44 45 /* Select an alternative, minimalistic output than the original one */ 46 #define TRACE_BLK_OPT_CLASSIC 0x1 47 48 static struct tracer_opt blk_tracer_opts[] = { 49 /* Default disable the minimalistic output */ 50 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 51 { } 52 }; 53 54 static struct tracer_flags blk_tracer_flags = { 55 .val = 0, 56 .opts = blk_tracer_opts, 57 }; 58 59 /* Global reference count of probes */ 60 static atomic_t blk_probes_ref = ATOMIC_INIT(0); 61 62 static void blk_register_tracepoints(void); 63 static void blk_unregister_tracepoints(void); 64 65 /* 66 * Send out a notify message. 67 */ 68 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 69 const void *data, size_t len) 70 { 71 struct blk_io_trace *t; 72 struct ring_buffer_event *event = NULL; 73 struct ring_buffer *buffer = NULL; 74 int pc = 0; 75 int cpu = smp_processor_id(); 76 bool blk_tracer = blk_tracer_enabled; 77 78 if (blk_tracer) { 79 buffer = blk_tr->trace_buffer.buffer; 80 pc = preempt_count(); 81 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 82 sizeof(*t) + len, 83 0, pc); 84 if (!event) 85 return; 86 t = ring_buffer_event_data(event); 87 goto record_it; 88 } 89 90 if (!bt->rchan) 91 return; 92 93 t = relay_reserve(bt->rchan, sizeof(*t) + len); 94 if (t) { 95 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 96 t->time = ktime_to_ns(ktime_get()); 97 record_it: 98 t->device = bt->dev; 99 t->action = action; 100 t->pid = pid; 101 t->cpu = cpu; 102 t->pdu_len = len; 103 memcpy((void *) t + sizeof(*t), data, len); 104 105 if (blk_tracer) 106 trace_buffer_unlock_commit(buffer, event, 0, pc); 107 } 108 } 109 110 /* 111 * Send out a notify for this process, if we haven't done so since a trace 112 * started 113 */ 114 static void trace_note_tsk(struct task_struct *tsk) 115 { 116 unsigned long flags; 117 struct blk_trace *bt; 118 119 tsk->btrace_seq = blktrace_seq; 120 spin_lock_irqsave(&running_trace_lock, flags); 121 list_for_each_entry(bt, &running_trace_list, running_list) { 122 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, 123 sizeof(tsk->comm)); 124 } 125 spin_unlock_irqrestore(&running_trace_lock, flags); 126 } 127 128 static void trace_note_time(struct blk_trace *bt) 129 { 130 struct timespec now; 131 unsigned long flags; 132 u32 words[2]; 133 134 getnstimeofday(&now); 135 words[0] = now.tv_sec; 136 words[1] = now.tv_nsec; 137 138 local_irq_save(flags); 139 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); 140 local_irq_restore(flags); 141 } 142 143 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 144 { 145 int n; 146 va_list args; 147 unsigned long flags; 148 char *buf; 149 150 if (unlikely(bt->trace_state != Blktrace_running && 151 !blk_tracer_enabled)) 152 return; 153 154 /* 155 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note 156 * message to the trace. 157 */ 158 if (!(bt->act_mask & BLK_TC_NOTIFY)) 159 return; 160 161 local_irq_save(flags); 162 buf = this_cpu_ptr(bt->msg_data); 163 va_start(args, fmt); 164 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 165 va_end(args); 166 167 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); 168 local_irq_restore(flags); 169 } 170 EXPORT_SYMBOL_GPL(__trace_note_message); 171 172 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 173 pid_t pid) 174 { 175 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 176 return 1; 177 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 178 return 1; 179 if (bt->pid && pid != bt->pid) 180 return 1; 181 182 return 0; 183 } 184 185 /* 186 * Data direction bit lookup 187 */ 188 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 189 BLK_TC_ACT(BLK_TC_WRITE) }; 190 191 #define BLK_TC_RAHEAD BLK_TC_AHEAD 192 193 /* The ilog2() calls fall out because they're constant */ 194 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \ 195 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name)) 196 197 /* 198 * The worker for the various blk_add_trace*() types. Fills out a 199 * blk_io_trace structure and places it in a per-cpu subbuffer. 200 */ 201 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 202 int rw, u32 what, int error, int pdu_len, void *pdu_data) 203 { 204 struct task_struct *tsk = current; 205 struct ring_buffer_event *event = NULL; 206 struct ring_buffer *buffer = NULL; 207 struct blk_io_trace *t; 208 unsigned long flags = 0; 209 unsigned long *sequence; 210 pid_t pid; 211 int cpu, pc = 0; 212 bool blk_tracer = blk_tracer_enabled; 213 214 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 215 return; 216 217 what |= ddir_act[rw & WRITE]; 218 what |= MASK_TC_BIT(rw, SYNC); 219 what |= MASK_TC_BIT(rw, RAHEAD); 220 what |= MASK_TC_BIT(rw, META); 221 what |= MASK_TC_BIT(rw, DISCARD); 222 what |= MASK_TC_BIT(rw, FLUSH); 223 what |= MASK_TC_BIT(rw, FUA); 224 225 pid = tsk->pid; 226 if (act_log_check(bt, what, sector, pid)) 227 return; 228 cpu = raw_smp_processor_id(); 229 230 if (blk_tracer) { 231 tracing_record_cmdline(current); 232 233 buffer = blk_tr->trace_buffer.buffer; 234 pc = preempt_count(); 235 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 236 sizeof(*t) + pdu_len, 237 0, pc); 238 if (!event) 239 return; 240 t = ring_buffer_event_data(event); 241 goto record_it; 242 } 243 244 if (unlikely(tsk->btrace_seq != blktrace_seq)) 245 trace_note_tsk(tsk); 246 247 /* 248 * A word about the locking here - we disable interrupts to reserve 249 * some space in the relay per-cpu buffer, to prevent an irq 250 * from coming in and stepping on our toes. 251 */ 252 local_irq_save(flags); 253 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 254 if (t) { 255 sequence = per_cpu_ptr(bt->sequence, cpu); 256 257 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 258 t->sequence = ++(*sequence); 259 t->time = ktime_to_ns(ktime_get()); 260 record_it: 261 /* 262 * These two are not needed in ftrace as they are in the 263 * generic trace_entry, filled by tracing_generic_entry_update, 264 * but for the trace_event->bin() synthesizer benefit we do it 265 * here too. 266 */ 267 t->cpu = cpu; 268 t->pid = pid; 269 270 t->sector = sector; 271 t->bytes = bytes; 272 t->action = what; 273 t->device = bt->dev; 274 t->error = error; 275 t->pdu_len = pdu_len; 276 277 if (pdu_len) 278 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 279 280 if (blk_tracer) { 281 trace_buffer_unlock_commit(buffer, event, 0, pc); 282 return; 283 } 284 } 285 286 local_irq_restore(flags); 287 } 288 289 static struct dentry *blk_tree_root; 290 static DEFINE_MUTEX(blk_tree_mutex); 291 292 static void blk_trace_free(struct blk_trace *bt) 293 { 294 debugfs_remove(bt->msg_file); 295 debugfs_remove(bt->dropped_file); 296 relay_close(bt->rchan); 297 debugfs_remove(bt->dir); 298 free_percpu(bt->sequence); 299 free_percpu(bt->msg_data); 300 kfree(bt); 301 } 302 303 static void blk_trace_cleanup(struct blk_trace *bt) 304 { 305 blk_trace_free(bt); 306 if (atomic_dec_and_test(&blk_probes_ref)) 307 blk_unregister_tracepoints(); 308 } 309 310 int blk_trace_remove(struct request_queue *q) 311 { 312 struct blk_trace *bt; 313 314 bt = xchg(&q->blk_trace, NULL); 315 if (!bt) 316 return -EINVAL; 317 318 if (bt->trace_state != Blktrace_running) 319 blk_trace_cleanup(bt); 320 321 return 0; 322 } 323 EXPORT_SYMBOL_GPL(blk_trace_remove); 324 325 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 326 size_t count, loff_t *ppos) 327 { 328 struct blk_trace *bt = filp->private_data; 329 char buf[16]; 330 331 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 332 333 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 334 } 335 336 static const struct file_operations blk_dropped_fops = { 337 .owner = THIS_MODULE, 338 .open = simple_open, 339 .read = blk_dropped_read, 340 .llseek = default_llseek, 341 }; 342 343 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 344 size_t count, loff_t *ppos) 345 { 346 char *msg; 347 struct blk_trace *bt; 348 349 if (count >= BLK_TN_MAX_MSG) 350 return -EINVAL; 351 352 msg = kmalloc(count + 1, GFP_KERNEL); 353 if (msg == NULL) 354 return -ENOMEM; 355 356 if (copy_from_user(msg, buffer, count)) { 357 kfree(msg); 358 return -EFAULT; 359 } 360 361 msg[count] = '\0'; 362 bt = filp->private_data; 363 __trace_note_message(bt, "%s", msg); 364 kfree(msg); 365 366 return count; 367 } 368 369 static const struct file_operations blk_msg_fops = { 370 .owner = THIS_MODULE, 371 .open = simple_open, 372 .write = blk_msg_write, 373 .llseek = noop_llseek, 374 }; 375 376 /* 377 * Keep track of how many times we encountered a full subbuffer, to aid 378 * the user space app in telling how many lost events there were. 379 */ 380 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 381 void *prev_subbuf, size_t prev_padding) 382 { 383 struct blk_trace *bt; 384 385 if (!relay_buf_full(buf)) 386 return 1; 387 388 bt = buf->chan->private_data; 389 atomic_inc(&bt->dropped); 390 return 0; 391 } 392 393 static int blk_remove_buf_file_callback(struct dentry *dentry) 394 { 395 debugfs_remove(dentry); 396 397 return 0; 398 } 399 400 static struct dentry *blk_create_buf_file_callback(const char *filename, 401 struct dentry *parent, 402 umode_t mode, 403 struct rchan_buf *buf, 404 int *is_global) 405 { 406 return debugfs_create_file(filename, mode, parent, buf, 407 &relay_file_operations); 408 } 409 410 static struct rchan_callbacks blk_relay_callbacks = { 411 .subbuf_start = blk_subbuf_start_callback, 412 .create_buf_file = blk_create_buf_file_callback, 413 .remove_buf_file = blk_remove_buf_file_callback, 414 }; 415 416 static void blk_trace_setup_lba(struct blk_trace *bt, 417 struct block_device *bdev) 418 { 419 struct hd_struct *part = NULL; 420 421 if (bdev) 422 part = bdev->bd_part; 423 424 if (part) { 425 bt->start_lba = part->start_sect; 426 bt->end_lba = part->start_sect + part->nr_sects; 427 } else { 428 bt->start_lba = 0; 429 bt->end_lba = -1ULL; 430 } 431 } 432 433 /* 434 * Setup everything required to start tracing 435 */ 436 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 437 struct block_device *bdev, 438 struct blk_user_trace_setup *buts) 439 { 440 struct blk_trace *old_bt, *bt = NULL; 441 struct dentry *dir = NULL; 442 int ret; 443 444 if (!buts->buf_size || !buts->buf_nr) 445 return -EINVAL; 446 447 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 448 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 449 450 /* 451 * some device names have larger paths - convert the slashes 452 * to underscores for this to work as expected 453 */ 454 strreplace(buts->name, '/', '_'); 455 456 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 457 if (!bt) 458 return -ENOMEM; 459 460 ret = -ENOMEM; 461 bt->sequence = alloc_percpu(unsigned long); 462 if (!bt->sequence) 463 goto err; 464 465 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 466 if (!bt->msg_data) 467 goto err; 468 469 ret = -ENOENT; 470 471 mutex_lock(&blk_tree_mutex); 472 if (!blk_tree_root) { 473 blk_tree_root = debugfs_create_dir("block", NULL); 474 if (!blk_tree_root) { 475 mutex_unlock(&blk_tree_mutex); 476 goto err; 477 } 478 } 479 mutex_unlock(&blk_tree_mutex); 480 481 dir = debugfs_create_dir(buts->name, blk_tree_root); 482 483 if (!dir) 484 goto err; 485 486 bt->dir = dir; 487 bt->dev = dev; 488 atomic_set(&bt->dropped, 0); 489 INIT_LIST_HEAD(&bt->running_list); 490 491 ret = -EIO; 492 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 493 &blk_dropped_fops); 494 if (!bt->dropped_file) 495 goto err; 496 497 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 498 if (!bt->msg_file) 499 goto err; 500 501 bt->rchan = relay_open("trace", dir, buts->buf_size, 502 buts->buf_nr, &blk_relay_callbacks, bt); 503 if (!bt->rchan) 504 goto err; 505 506 bt->act_mask = buts->act_mask; 507 if (!bt->act_mask) 508 bt->act_mask = (u16) -1; 509 510 blk_trace_setup_lba(bt, bdev); 511 512 /* overwrite with user settings */ 513 if (buts->start_lba) 514 bt->start_lba = buts->start_lba; 515 if (buts->end_lba) 516 bt->end_lba = buts->end_lba; 517 518 bt->pid = buts->pid; 519 bt->trace_state = Blktrace_setup; 520 521 ret = -EBUSY; 522 old_bt = xchg(&q->blk_trace, bt); 523 if (old_bt) { 524 (void) xchg(&q->blk_trace, old_bt); 525 goto err; 526 } 527 528 if (atomic_inc_return(&blk_probes_ref) == 1) 529 blk_register_tracepoints(); 530 531 return 0; 532 err: 533 blk_trace_free(bt); 534 return ret; 535 } 536 537 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 538 struct block_device *bdev, 539 char __user *arg) 540 { 541 struct blk_user_trace_setup buts; 542 int ret; 543 544 ret = copy_from_user(&buts, arg, sizeof(buts)); 545 if (ret) 546 return -EFAULT; 547 548 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 549 if (ret) 550 return ret; 551 552 if (copy_to_user(arg, &buts, sizeof(buts))) { 553 blk_trace_remove(q); 554 return -EFAULT; 555 } 556 return 0; 557 } 558 EXPORT_SYMBOL_GPL(blk_trace_setup); 559 560 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 561 static int compat_blk_trace_setup(struct request_queue *q, char *name, 562 dev_t dev, struct block_device *bdev, 563 char __user *arg) 564 { 565 struct blk_user_trace_setup buts; 566 struct compat_blk_user_trace_setup cbuts; 567 int ret; 568 569 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 570 return -EFAULT; 571 572 buts = (struct blk_user_trace_setup) { 573 .act_mask = cbuts.act_mask, 574 .buf_size = cbuts.buf_size, 575 .buf_nr = cbuts.buf_nr, 576 .start_lba = cbuts.start_lba, 577 .end_lba = cbuts.end_lba, 578 .pid = cbuts.pid, 579 }; 580 581 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 582 if (ret) 583 return ret; 584 585 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) { 586 blk_trace_remove(q); 587 return -EFAULT; 588 } 589 590 return 0; 591 } 592 #endif 593 594 int blk_trace_startstop(struct request_queue *q, int start) 595 { 596 int ret; 597 struct blk_trace *bt = q->blk_trace; 598 599 if (bt == NULL) 600 return -EINVAL; 601 602 /* 603 * For starting a trace, we can transition from a setup or stopped 604 * trace. For stopping a trace, the state must be running 605 */ 606 ret = -EINVAL; 607 if (start) { 608 if (bt->trace_state == Blktrace_setup || 609 bt->trace_state == Blktrace_stopped) { 610 blktrace_seq++; 611 smp_mb(); 612 bt->trace_state = Blktrace_running; 613 spin_lock_irq(&running_trace_lock); 614 list_add(&bt->running_list, &running_trace_list); 615 spin_unlock_irq(&running_trace_lock); 616 617 trace_note_time(bt); 618 ret = 0; 619 } 620 } else { 621 if (bt->trace_state == Blktrace_running) { 622 bt->trace_state = Blktrace_stopped; 623 spin_lock_irq(&running_trace_lock); 624 list_del_init(&bt->running_list); 625 spin_unlock_irq(&running_trace_lock); 626 relay_flush(bt->rchan); 627 ret = 0; 628 } 629 } 630 631 return ret; 632 } 633 EXPORT_SYMBOL_GPL(blk_trace_startstop); 634 635 /** 636 * blk_trace_ioctl: - handle the ioctls associated with tracing 637 * @bdev: the block device 638 * @cmd: the ioctl cmd 639 * @arg: the argument data, if any 640 * 641 **/ 642 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 643 { 644 struct request_queue *q; 645 int ret, start = 0; 646 char b[BDEVNAME_SIZE]; 647 648 q = bdev_get_queue(bdev); 649 if (!q) 650 return -ENXIO; 651 652 mutex_lock(&bdev->bd_mutex); 653 654 switch (cmd) { 655 case BLKTRACESETUP: 656 bdevname(bdev, b); 657 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 658 break; 659 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 660 case BLKTRACESETUP32: 661 bdevname(bdev, b); 662 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 663 break; 664 #endif 665 case BLKTRACESTART: 666 start = 1; 667 case BLKTRACESTOP: 668 ret = blk_trace_startstop(q, start); 669 break; 670 case BLKTRACETEARDOWN: 671 ret = blk_trace_remove(q); 672 break; 673 default: 674 ret = -ENOTTY; 675 break; 676 } 677 678 mutex_unlock(&bdev->bd_mutex); 679 return ret; 680 } 681 682 /** 683 * blk_trace_shutdown: - stop and cleanup trace structures 684 * @q: the request queue associated with the device 685 * 686 **/ 687 void blk_trace_shutdown(struct request_queue *q) 688 { 689 if (q->blk_trace) { 690 blk_trace_startstop(q, 0); 691 blk_trace_remove(q); 692 } 693 } 694 695 /* 696 * blktrace probes 697 */ 698 699 /** 700 * blk_add_trace_rq - Add a trace for a request oriented action 701 * @q: queue the io is for 702 * @rq: the source request 703 * @nr_bytes: number of completed bytes 704 * @what: the action 705 * 706 * Description: 707 * Records an action against a request. Will log the bio offset + size. 708 * 709 **/ 710 static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 711 unsigned int nr_bytes, u32 what) 712 { 713 struct blk_trace *bt = q->blk_trace; 714 715 if (likely(!bt)) 716 return; 717 718 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { 719 what |= BLK_TC_ACT(BLK_TC_PC); 720 __blk_add_trace(bt, 0, nr_bytes, rq->cmd_flags, 721 what, rq->errors, rq->cmd_len, rq->cmd); 722 } else { 723 what |= BLK_TC_ACT(BLK_TC_FS); 724 __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes, 725 rq->cmd_flags, what, rq->errors, 0, NULL); 726 } 727 } 728 729 static void blk_add_trace_rq_abort(void *ignore, 730 struct request_queue *q, struct request *rq) 731 { 732 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT); 733 } 734 735 static void blk_add_trace_rq_insert(void *ignore, 736 struct request_queue *q, struct request *rq) 737 { 738 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT); 739 } 740 741 static void blk_add_trace_rq_issue(void *ignore, 742 struct request_queue *q, struct request *rq) 743 { 744 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE); 745 } 746 747 static void blk_add_trace_rq_requeue(void *ignore, 748 struct request_queue *q, 749 struct request *rq) 750 { 751 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE); 752 } 753 754 static void blk_add_trace_rq_complete(void *ignore, 755 struct request_queue *q, 756 struct request *rq, 757 unsigned int nr_bytes) 758 { 759 blk_add_trace_rq(q, rq, nr_bytes, BLK_TA_COMPLETE); 760 } 761 762 /** 763 * blk_add_trace_bio - Add a trace for a bio oriented action 764 * @q: queue the io is for 765 * @bio: the source bio 766 * @what: the action 767 * @error: error, if any 768 * 769 * Description: 770 * Records an action against a bio. Will log the bio offset + size. 771 * 772 **/ 773 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 774 u32 what, int error) 775 { 776 struct blk_trace *bt = q->blk_trace; 777 778 if (likely(!bt)) 779 return; 780 781 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 782 bio->bi_rw, what, error, 0, NULL); 783 } 784 785 static void blk_add_trace_bio_bounce(void *ignore, 786 struct request_queue *q, struct bio *bio) 787 { 788 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0); 789 } 790 791 static void blk_add_trace_bio_complete(void *ignore, 792 struct request_queue *q, struct bio *bio, 793 int error) 794 { 795 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error); 796 } 797 798 static void blk_add_trace_bio_backmerge(void *ignore, 799 struct request_queue *q, 800 struct request *rq, 801 struct bio *bio) 802 { 803 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0); 804 } 805 806 static void blk_add_trace_bio_frontmerge(void *ignore, 807 struct request_queue *q, 808 struct request *rq, 809 struct bio *bio) 810 { 811 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0); 812 } 813 814 static void blk_add_trace_bio_queue(void *ignore, 815 struct request_queue *q, struct bio *bio) 816 { 817 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0); 818 } 819 820 static void blk_add_trace_getrq(void *ignore, 821 struct request_queue *q, 822 struct bio *bio, int rw) 823 { 824 if (bio) 825 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0); 826 else { 827 struct blk_trace *bt = q->blk_trace; 828 829 if (bt) 830 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); 831 } 832 } 833 834 835 static void blk_add_trace_sleeprq(void *ignore, 836 struct request_queue *q, 837 struct bio *bio, int rw) 838 { 839 if (bio) 840 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0); 841 else { 842 struct blk_trace *bt = q->blk_trace; 843 844 if (bt) 845 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 846 0, 0, NULL); 847 } 848 } 849 850 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 851 { 852 struct blk_trace *bt = q->blk_trace; 853 854 if (bt) 855 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 856 } 857 858 static void blk_add_trace_unplug(void *ignore, struct request_queue *q, 859 unsigned int depth, bool explicit) 860 { 861 struct blk_trace *bt = q->blk_trace; 862 863 if (bt) { 864 __be64 rpdu = cpu_to_be64(depth); 865 u32 what; 866 867 if (explicit) 868 what = BLK_TA_UNPLUG_IO; 869 else 870 what = BLK_TA_UNPLUG_TIMER; 871 872 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu); 873 } 874 } 875 876 static void blk_add_trace_split(void *ignore, 877 struct request_queue *q, struct bio *bio, 878 unsigned int pdu) 879 { 880 struct blk_trace *bt = q->blk_trace; 881 882 if (bt) { 883 __be64 rpdu = cpu_to_be64(pdu); 884 885 __blk_add_trace(bt, bio->bi_iter.bi_sector, 886 bio->bi_iter.bi_size, bio->bi_rw, BLK_TA_SPLIT, 887 bio->bi_error, sizeof(rpdu), &rpdu); 888 } 889 } 890 891 /** 892 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation 893 * @ignore: trace callback data parameter (not used) 894 * @q: queue the io is for 895 * @bio: the source bio 896 * @dev: target device 897 * @from: source sector 898 * 899 * Description: 900 * Device mapper or raid target sometimes need to split a bio because 901 * it spans a stripe (or similar). Add a trace for that action. 902 * 903 **/ 904 static void blk_add_trace_bio_remap(void *ignore, 905 struct request_queue *q, struct bio *bio, 906 dev_t dev, sector_t from) 907 { 908 struct blk_trace *bt = q->blk_trace; 909 struct blk_io_trace_remap r; 910 911 if (likely(!bt)) 912 return; 913 914 r.device_from = cpu_to_be32(dev); 915 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 916 r.sector_from = cpu_to_be64(from); 917 918 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 919 bio->bi_rw, BLK_TA_REMAP, bio->bi_error, 920 sizeof(r), &r); 921 } 922 923 /** 924 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 925 * @ignore: trace callback data parameter (not used) 926 * @q: queue the io is for 927 * @rq: the source request 928 * @dev: target device 929 * @from: source sector 930 * 931 * Description: 932 * Device mapper remaps request to other devices. 933 * Add a trace for that action. 934 * 935 **/ 936 static void blk_add_trace_rq_remap(void *ignore, 937 struct request_queue *q, 938 struct request *rq, dev_t dev, 939 sector_t from) 940 { 941 struct blk_trace *bt = q->blk_trace; 942 struct blk_io_trace_remap r; 943 944 if (likely(!bt)) 945 return; 946 947 r.device_from = cpu_to_be32(dev); 948 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 949 r.sector_from = cpu_to_be64(from); 950 951 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 952 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors, 953 sizeof(r), &r); 954 } 955 956 /** 957 * blk_add_driver_data - Add binary message with driver-specific data 958 * @q: queue the io is for 959 * @rq: io request 960 * @data: driver-specific data 961 * @len: length of driver-specific data 962 * 963 * Description: 964 * Some drivers might want to write driver-specific data per request. 965 * 966 **/ 967 void blk_add_driver_data(struct request_queue *q, 968 struct request *rq, 969 void *data, size_t len) 970 { 971 struct blk_trace *bt = q->blk_trace; 972 973 if (likely(!bt)) 974 return; 975 976 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) 977 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 978 BLK_TA_DRV_DATA, rq->errors, len, data); 979 else 980 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 981 BLK_TA_DRV_DATA, rq->errors, len, data); 982 } 983 EXPORT_SYMBOL_GPL(blk_add_driver_data); 984 985 static void blk_register_tracepoints(void) 986 { 987 int ret; 988 989 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 990 WARN_ON(ret); 991 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 992 WARN_ON(ret); 993 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 994 WARN_ON(ret); 995 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 996 WARN_ON(ret); 997 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 998 WARN_ON(ret); 999 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1000 WARN_ON(ret); 1001 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1002 WARN_ON(ret); 1003 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1004 WARN_ON(ret); 1005 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1006 WARN_ON(ret); 1007 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1008 WARN_ON(ret); 1009 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 1010 WARN_ON(ret); 1011 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1012 WARN_ON(ret); 1013 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 1014 WARN_ON(ret); 1015 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL); 1016 WARN_ON(ret); 1017 ret = register_trace_block_split(blk_add_trace_split, NULL); 1018 WARN_ON(ret); 1019 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1020 WARN_ON(ret); 1021 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1022 WARN_ON(ret); 1023 } 1024 1025 static void blk_unregister_tracepoints(void) 1026 { 1027 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1028 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1029 unregister_trace_block_split(blk_add_trace_split, NULL); 1030 unregister_trace_block_unplug(blk_add_trace_unplug, NULL); 1031 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1032 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1033 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1034 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1035 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1036 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1037 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1038 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1039 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1040 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1041 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1042 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1043 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 1044 1045 tracepoint_synchronize_unregister(); 1046 } 1047 1048 /* 1049 * struct blk_io_tracer formatting routines 1050 */ 1051 1052 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1053 { 1054 int i = 0; 1055 int tc = t->action >> BLK_TC_SHIFT; 1056 1057 if (t->action == BLK_TN_MESSAGE) { 1058 rwbs[i++] = 'N'; 1059 goto out; 1060 } 1061 1062 if (tc & BLK_TC_FLUSH) 1063 rwbs[i++] = 'F'; 1064 1065 if (tc & BLK_TC_DISCARD) 1066 rwbs[i++] = 'D'; 1067 else if (tc & BLK_TC_WRITE) 1068 rwbs[i++] = 'W'; 1069 else if (t->bytes) 1070 rwbs[i++] = 'R'; 1071 else 1072 rwbs[i++] = 'N'; 1073 1074 if (tc & BLK_TC_FUA) 1075 rwbs[i++] = 'F'; 1076 if (tc & BLK_TC_AHEAD) 1077 rwbs[i++] = 'A'; 1078 if (tc & BLK_TC_SYNC) 1079 rwbs[i++] = 'S'; 1080 if (tc & BLK_TC_META) 1081 rwbs[i++] = 'M'; 1082 out: 1083 rwbs[i] = '\0'; 1084 } 1085 1086 static inline 1087 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1088 { 1089 return (const struct blk_io_trace *)ent; 1090 } 1091 1092 static inline const void *pdu_start(const struct trace_entry *ent) 1093 { 1094 return te_blk_io_trace(ent) + 1; 1095 } 1096 1097 static inline u32 t_action(const struct trace_entry *ent) 1098 { 1099 return te_blk_io_trace(ent)->action; 1100 } 1101 1102 static inline u32 t_bytes(const struct trace_entry *ent) 1103 { 1104 return te_blk_io_trace(ent)->bytes; 1105 } 1106 1107 static inline u32 t_sec(const struct trace_entry *ent) 1108 { 1109 return te_blk_io_trace(ent)->bytes >> 9; 1110 } 1111 1112 static inline unsigned long long t_sector(const struct trace_entry *ent) 1113 { 1114 return te_blk_io_trace(ent)->sector; 1115 } 1116 1117 static inline __u16 t_error(const struct trace_entry *ent) 1118 { 1119 return te_blk_io_trace(ent)->error; 1120 } 1121 1122 static __u64 get_pdu_int(const struct trace_entry *ent) 1123 { 1124 const __u64 *val = pdu_start(ent); 1125 return be64_to_cpu(*val); 1126 } 1127 1128 static void get_pdu_remap(const struct trace_entry *ent, 1129 struct blk_io_trace_remap *r) 1130 { 1131 const struct blk_io_trace_remap *__r = pdu_start(ent); 1132 __u64 sector_from = __r->sector_from; 1133 1134 r->device_from = be32_to_cpu(__r->device_from); 1135 r->device_to = be32_to_cpu(__r->device_to); 1136 r->sector_from = be64_to_cpu(sector_from); 1137 } 1138 1139 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1140 1141 static void blk_log_action_classic(struct trace_iterator *iter, const char *act) 1142 { 1143 char rwbs[RWBS_LEN]; 1144 unsigned long long ts = iter->ts; 1145 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1146 unsigned secs = (unsigned long)ts; 1147 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1148 1149 fill_rwbs(rwbs, t); 1150 1151 trace_seq_printf(&iter->seq, 1152 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1153 MAJOR(t->device), MINOR(t->device), iter->cpu, 1154 secs, nsec_rem, iter->ent->pid, act, rwbs); 1155 } 1156 1157 static void blk_log_action(struct trace_iterator *iter, const char *act) 1158 { 1159 char rwbs[RWBS_LEN]; 1160 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1161 1162 fill_rwbs(rwbs, t); 1163 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1164 MAJOR(t->device), MINOR(t->device), act, rwbs); 1165 } 1166 1167 static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1168 { 1169 const unsigned char *pdu_buf; 1170 int pdu_len; 1171 int i, end; 1172 1173 pdu_buf = pdu_start(ent); 1174 pdu_len = te_blk_io_trace(ent)->pdu_len; 1175 1176 if (!pdu_len) 1177 return; 1178 1179 /* find the last zero that needs to be printed */ 1180 for (end = pdu_len - 1; end >= 0; end--) 1181 if (pdu_buf[end]) 1182 break; 1183 end++; 1184 1185 trace_seq_putc(s, '('); 1186 1187 for (i = 0; i < pdu_len; i++) { 1188 1189 trace_seq_printf(s, "%s%02x", 1190 i == 0 ? "" : " ", pdu_buf[i]); 1191 1192 /* 1193 * stop when the rest is just zeroes and indicate so 1194 * with a ".." appended 1195 */ 1196 if (i == end && end != pdu_len - 1) { 1197 trace_seq_puts(s, " ..) "); 1198 return; 1199 } 1200 } 1201 1202 trace_seq_puts(s, ") "); 1203 } 1204 1205 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1206 { 1207 char cmd[TASK_COMM_LEN]; 1208 1209 trace_find_cmdline(ent->pid, cmd); 1210 1211 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1212 trace_seq_printf(s, "%u ", t_bytes(ent)); 1213 blk_log_dump_pdu(s, ent); 1214 trace_seq_printf(s, "[%s]\n", cmd); 1215 } else { 1216 if (t_sec(ent)) 1217 trace_seq_printf(s, "%llu + %u [%s]\n", 1218 t_sector(ent), t_sec(ent), cmd); 1219 else 1220 trace_seq_printf(s, "[%s]\n", cmd); 1221 } 1222 } 1223 1224 static void blk_log_with_error(struct trace_seq *s, 1225 const struct trace_entry *ent) 1226 { 1227 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1228 blk_log_dump_pdu(s, ent); 1229 trace_seq_printf(s, "[%d]\n", t_error(ent)); 1230 } else { 1231 if (t_sec(ent)) 1232 trace_seq_printf(s, "%llu + %u [%d]\n", 1233 t_sector(ent), 1234 t_sec(ent), t_error(ent)); 1235 else 1236 trace_seq_printf(s, "%llu [%d]\n", 1237 t_sector(ent), t_error(ent)); 1238 } 1239 } 1240 1241 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1242 { 1243 struct blk_io_trace_remap r = { .device_from = 0, }; 1244 1245 get_pdu_remap(ent, &r); 1246 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1247 t_sector(ent), t_sec(ent), 1248 MAJOR(r.device_from), MINOR(r.device_from), 1249 (unsigned long long)r.sector_from); 1250 } 1251 1252 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1253 { 1254 char cmd[TASK_COMM_LEN]; 1255 1256 trace_find_cmdline(ent->pid, cmd); 1257 1258 trace_seq_printf(s, "[%s]\n", cmd); 1259 } 1260 1261 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1262 { 1263 char cmd[TASK_COMM_LEN]; 1264 1265 trace_find_cmdline(ent->pid, cmd); 1266 1267 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1268 } 1269 1270 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1271 { 1272 char cmd[TASK_COMM_LEN]; 1273 1274 trace_find_cmdline(ent->pid, cmd); 1275 1276 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1277 get_pdu_int(ent), cmd); 1278 } 1279 1280 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1281 { 1282 const struct blk_io_trace *t = te_blk_io_trace(ent); 1283 1284 trace_seq_putmem(s, t + 1, t->pdu_len); 1285 trace_seq_putc(s, '\n'); 1286 } 1287 1288 /* 1289 * struct tracer operations 1290 */ 1291 1292 static void blk_tracer_print_header(struct seq_file *m) 1293 { 1294 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1295 return; 1296 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1297 "# | | | | | |\n"); 1298 } 1299 1300 static void blk_tracer_start(struct trace_array *tr) 1301 { 1302 blk_tracer_enabled = true; 1303 } 1304 1305 static int blk_tracer_init(struct trace_array *tr) 1306 { 1307 blk_tr = tr; 1308 blk_tracer_start(tr); 1309 return 0; 1310 } 1311 1312 static void blk_tracer_stop(struct trace_array *tr) 1313 { 1314 blk_tracer_enabled = false; 1315 } 1316 1317 static void blk_tracer_reset(struct trace_array *tr) 1318 { 1319 blk_tracer_stop(tr); 1320 } 1321 1322 static const struct { 1323 const char *act[2]; 1324 void (*print)(struct trace_seq *s, const struct trace_entry *ent); 1325 } what2act[] = { 1326 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1327 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1328 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1329 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1330 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1331 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1332 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1333 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1334 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1335 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1336 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1337 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1338 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1339 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1340 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1341 }; 1342 1343 static enum print_line_t print_one_line(struct trace_iterator *iter, 1344 bool classic) 1345 { 1346 struct trace_seq *s = &iter->seq; 1347 const struct blk_io_trace *t; 1348 u16 what; 1349 bool long_act; 1350 blk_log_action_t *log_action; 1351 1352 t = te_blk_io_trace(iter->ent); 1353 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1354 long_act = !!(trace_flags & TRACE_ITER_VERBOSE); 1355 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1356 1357 if (t->action == BLK_TN_MESSAGE) { 1358 log_action(iter, long_act ? "message" : "m"); 1359 blk_log_msg(s, iter->ent); 1360 } 1361 1362 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1363 trace_seq_printf(s, "Unknown action %x\n", what); 1364 else { 1365 log_action(iter, what2act[what].act[long_act]); 1366 what2act[what].print(s, iter->ent); 1367 } 1368 1369 return trace_handle_return(s); 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 void 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 trace_seq_putmem(s, &old, offset); 1389 trace_seq_putmem(s, &t->sector, 1390 sizeof(old) - offset + t->pdu_len); 1391 } 1392 1393 static enum print_line_t 1394 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1395 struct trace_event *event) 1396 { 1397 blk_trace_synthesize_old_trace(iter); 1398 1399 return trace_handle_return(&iter->seq); 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 1411 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) 1412 { 1413 /* don't output context-info for blk_classic output */ 1414 if (bit == TRACE_BLK_OPT_CLASSIC) { 1415 if (set) 1416 trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1417 else 1418 trace_flags |= TRACE_ITER_CONTEXT_INFO; 1419 } 1420 return 0; 1421 } 1422 1423 static struct tracer blk_tracer __read_mostly = { 1424 .name = "blk", 1425 .init = blk_tracer_init, 1426 .reset = blk_tracer_reset, 1427 .start = blk_tracer_start, 1428 .stop = blk_tracer_stop, 1429 .print_header = blk_tracer_print_header, 1430 .print_line = blk_tracer_print_line, 1431 .flags = &blk_tracer_flags, 1432 .set_flag = blk_tracer_set_flag, 1433 }; 1434 1435 static struct trace_event_functions trace_blk_event_funcs = { 1436 .trace = blk_trace_event_print, 1437 .binary = blk_trace_event_print_binary, 1438 }; 1439 1440 static struct trace_event trace_blk_event = { 1441 .type = TRACE_BLK, 1442 .funcs = &trace_blk_event_funcs, 1443 }; 1444 1445 static int __init init_blk_tracer(void) 1446 { 1447 if (!register_trace_event(&trace_blk_event)) { 1448 pr_warning("Warning: could not register block events\n"); 1449 return 1; 1450 } 1451 1452 if (register_tracer(&blk_tracer) != 0) { 1453 pr_warning("Warning: could not register the block tracer\n"); 1454 unregister_trace_event(&trace_blk_event); 1455 return 1; 1456 } 1457 1458 return 0; 1459 } 1460 1461 device_initcall(init_blk_tracer); 1462 1463 static int blk_trace_remove_queue(struct request_queue *q) 1464 { 1465 struct blk_trace *bt; 1466 1467 bt = xchg(&q->blk_trace, NULL); 1468 if (bt == NULL) 1469 return -EINVAL; 1470 1471 if (atomic_dec_and_test(&blk_probes_ref)) 1472 blk_unregister_tracepoints(); 1473 1474 blk_trace_free(bt); 1475 return 0; 1476 } 1477 1478 /* 1479 * Setup everything required to start tracing 1480 */ 1481 static int blk_trace_setup_queue(struct request_queue *q, 1482 struct block_device *bdev) 1483 { 1484 struct blk_trace *old_bt, *bt = NULL; 1485 int ret = -ENOMEM; 1486 1487 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1488 if (!bt) 1489 return -ENOMEM; 1490 1491 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1492 if (!bt->msg_data) 1493 goto free_bt; 1494 1495 bt->dev = bdev->bd_dev; 1496 bt->act_mask = (u16)-1; 1497 1498 blk_trace_setup_lba(bt, bdev); 1499 1500 old_bt = xchg(&q->blk_trace, bt); 1501 if (old_bt != NULL) { 1502 (void)xchg(&q->blk_trace, old_bt); 1503 ret = -EBUSY; 1504 goto free_bt; 1505 } 1506 1507 if (atomic_inc_return(&blk_probes_ref) == 1) 1508 blk_register_tracepoints(); 1509 return 0; 1510 1511 free_bt: 1512 blk_trace_free(bt); 1513 return ret; 1514 } 1515 1516 /* 1517 * sysfs interface to enable and configure tracing 1518 */ 1519 1520 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1521 struct device_attribute *attr, 1522 char *buf); 1523 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1524 struct device_attribute *attr, 1525 const char *buf, size_t count); 1526 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1527 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1528 sysfs_blk_trace_attr_show, \ 1529 sysfs_blk_trace_attr_store) 1530 1531 static BLK_TRACE_DEVICE_ATTR(enable); 1532 static BLK_TRACE_DEVICE_ATTR(act_mask); 1533 static BLK_TRACE_DEVICE_ATTR(pid); 1534 static BLK_TRACE_DEVICE_ATTR(start_lba); 1535 static BLK_TRACE_DEVICE_ATTR(end_lba); 1536 1537 static struct attribute *blk_trace_attrs[] = { 1538 &dev_attr_enable.attr, 1539 &dev_attr_act_mask.attr, 1540 &dev_attr_pid.attr, 1541 &dev_attr_start_lba.attr, 1542 &dev_attr_end_lba.attr, 1543 NULL 1544 }; 1545 1546 struct attribute_group blk_trace_attr_group = { 1547 .name = "trace", 1548 .attrs = blk_trace_attrs, 1549 }; 1550 1551 static const struct { 1552 int mask; 1553 const char *str; 1554 } mask_maps[] = { 1555 { BLK_TC_READ, "read" }, 1556 { BLK_TC_WRITE, "write" }, 1557 { BLK_TC_FLUSH, "flush" }, 1558 { BLK_TC_SYNC, "sync" }, 1559 { BLK_TC_QUEUE, "queue" }, 1560 { BLK_TC_REQUEUE, "requeue" }, 1561 { BLK_TC_ISSUE, "issue" }, 1562 { BLK_TC_COMPLETE, "complete" }, 1563 { BLK_TC_FS, "fs" }, 1564 { BLK_TC_PC, "pc" }, 1565 { BLK_TC_AHEAD, "ahead" }, 1566 { BLK_TC_META, "meta" }, 1567 { BLK_TC_DISCARD, "discard" }, 1568 { BLK_TC_DRV_DATA, "drv_data" }, 1569 { BLK_TC_FUA, "fua" }, 1570 }; 1571 1572 static int blk_trace_str2mask(const char *str) 1573 { 1574 int i; 1575 int mask = 0; 1576 char *buf, *s, *token; 1577 1578 buf = kstrdup(str, GFP_KERNEL); 1579 if (buf == NULL) 1580 return -ENOMEM; 1581 s = strstrip(buf); 1582 1583 while (1) { 1584 token = strsep(&s, ","); 1585 if (token == NULL) 1586 break; 1587 1588 if (*token == '\0') 1589 continue; 1590 1591 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1592 if (strcasecmp(token, mask_maps[i].str) == 0) { 1593 mask |= mask_maps[i].mask; 1594 break; 1595 } 1596 } 1597 if (i == ARRAY_SIZE(mask_maps)) { 1598 mask = -EINVAL; 1599 break; 1600 } 1601 } 1602 kfree(buf); 1603 1604 return mask; 1605 } 1606 1607 static ssize_t blk_trace_mask2str(char *buf, int mask) 1608 { 1609 int i; 1610 char *p = buf; 1611 1612 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1613 if (mask & mask_maps[i].mask) { 1614 p += sprintf(p, "%s%s", 1615 (p == buf) ? "" : ",", mask_maps[i].str); 1616 } 1617 } 1618 *p++ = '\n'; 1619 1620 return p - buf; 1621 } 1622 1623 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1624 { 1625 if (bdev->bd_disk == NULL) 1626 return NULL; 1627 1628 return bdev_get_queue(bdev); 1629 } 1630 1631 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1632 struct device_attribute *attr, 1633 char *buf) 1634 { 1635 struct hd_struct *p = dev_to_part(dev); 1636 struct request_queue *q; 1637 struct block_device *bdev; 1638 ssize_t ret = -ENXIO; 1639 1640 bdev = bdget(part_devt(p)); 1641 if (bdev == NULL) 1642 goto out; 1643 1644 q = blk_trace_get_queue(bdev); 1645 if (q == NULL) 1646 goto out_bdput; 1647 1648 mutex_lock(&bdev->bd_mutex); 1649 1650 if (attr == &dev_attr_enable) { 1651 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1652 goto out_unlock_bdev; 1653 } 1654 1655 if (q->blk_trace == NULL) 1656 ret = sprintf(buf, "disabled\n"); 1657 else if (attr == &dev_attr_act_mask) 1658 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1659 else if (attr == &dev_attr_pid) 1660 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1661 else if (attr == &dev_attr_start_lba) 1662 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1663 else if (attr == &dev_attr_end_lba) 1664 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1665 1666 out_unlock_bdev: 1667 mutex_unlock(&bdev->bd_mutex); 1668 out_bdput: 1669 bdput(bdev); 1670 out: 1671 return ret; 1672 } 1673 1674 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1675 struct device_attribute *attr, 1676 const char *buf, size_t count) 1677 { 1678 struct block_device *bdev; 1679 struct request_queue *q; 1680 struct hd_struct *p; 1681 u64 value; 1682 ssize_t ret = -EINVAL; 1683 1684 if (count == 0) 1685 goto out; 1686 1687 if (attr == &dev_attr_act_mask) { 1688 if (sscanf(buf, "%llx", &value) != 1) { 1689 /* Assume it is a list of trace category names */ 1690 ret = blk_trace_str2mask(buf); 1691 if (ret < 0) 1692 goto out; 1693 value = ret; 1694 } 1695 } else if (sscanf(buf, "%llu", &value) != 1) 1696 goto out; 1697 1698 ret = -ENXIO; 1699 1700 p = dev_to_part(dev); 1701 bdev = bdget(part_devt(p)); 1702 if (bdev == NULL) 1703 goto out; 1704 1705 q = blk_trace_get_queue(bdev); 1706 if (q == NULL) 1707 goto out_bdput; 1708 1709 mutex_lock(&bdev->bd_mutex); 1710 1711 if (attr == &dev_attr_enable) { 1712 if (value) 1713 ret = blk_trace_setup_queue(q, bdev); 1714 else 1715 ret = blk_trace_remove_queue(q); 1716 goto out_unlock_bdev; 1717 } 1718 1719 ret = 0; 1720 if (q->blk_trace == NULL) 1721 ret = blk_trace_setup_queue(q, bdev); 1722 1723 if (ret == 0) { 1724 if (attr == &dev_attr_act_mask) 1725 q->blk_trace->act_mask = value; 1726 else if (attr == &dev_attr_pid) 1727 q->blk_trace->pid = value; 1728 else if (attr == &dev_attr_start_lba) 1729 q->blk_trace->start_lba = value; 1730 else if (attr == &dev_attr_end_lba) 1731 q->blk_trace->end_lba = value; 1732 } 1733 1734 out_unlock_bdev: 1735 mutex_unlock(&bdev->bd_mutex); 1736 out_bdput: 1737 bdput(bdev); 1738 out: 1739 return ret ? ret : count; 1740 } 1741 1742 int blk_trace_init_sysfs(struct device *dev) 1743 { 1744 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1745 } 1746 1747 void blk_trace_remove_sysfs(struct device *dev) 1748 { 1749 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1750 } 1751 1752 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1753 1754 #ifdef CONFIG_EVENT_TRACING 1755 1756 void blk_dump_cmd(char *buf, struct request *rq) 1757 { 1758 int i, end; 1759 int len = rq->cmd_len; 1760 unsigned char *cmd = rq->cmd; 1761 1762 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) { 1763 buf[0] = '\0'; 1764 return; 1765 } 1766 1767 for (end = len - 1; end >= 0; end--) 1768 if (cmd[end]) 1769 break; 1770 end++; 1771 1772 for (i = 0; i < len; i++) { 1773 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1774 if (i == end && end != len - 1) { 1775 sprintf(buf, " .."); 1776 break; 1777 } 1778 } 1779 } 1780 1781 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) 1782 { 1783 int i = 0; 1784 1785 if (rw & REQ_FLUSH) 1786 rwbs[i++] = 'F'; 1787 1788 if (rw & WRITE) 1789 rwbs[i++] = 'W'; 1790 else if (rw & REQ_DISCARD) 1791 rwbs[i++] = 'D'; 1792 else if (bytes) 1793 rwbs[i++] = 'R'; 1794 else 1795 rwbs[i++] = 'N'; 1796 1797 if (rw & REQ_FUA) 1798 rwbs[i++] = 'F'; 1799 if (rw & REQ_RAHEAD) 1800 rwbs[i++] = 'A'; 1801 if (rw & REQ_SYNC) 1802 rwbs[i++] = 'S'; 1803 if (rw & REQ_META) 1804 rwbs[i++] = 'M'; 1805 if (rw & REQ_SECURE) 1806 rwbs[i++] = 'E'; 1807 1808 rwbs[i] = '\0'; 1809 } 1810 EXPORT_SYMBOL_GPL(blk_fill_rwbs); 1811 1812 #endif /* CONFIG_EVENT_TRACING */ 1813 1814