1 /* 2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 16 * 17 */ 18 #include <linux/kernel.h> 19 #include <linux/blkdev.h> 20 #include <linux/blktrace_api.h> 21 #include <linux/percpu.h> 22 #include <linux/init.h> 23 #include <linux/mutex.h> 24 #include <linux/slab.h> 25 #include <linux/debugfs.h> 26 #include <linux/smp_lock.h> 27 #include <linux/time.h> 28 #include <linux/uaccess.h> 29 30 #include <trace/events/block.h> 31 32 #include "trace_output.h" 33 34 #ifdef CONFIG_BLK_DEV_IO_TRACE 35 36 static unsigned int blktrace_seq __read_mostly = 1; 37 38 static struct trace_array *blk_tr; 39 static bool blk_tracer_enabled __read_mostly; 40 41 /* Select an alternative, minimalistic output than the original one */ 42 #define TRACE_BLK_OPT_CLASSIC 0x1 43 44 static struct tracer_opt blk_tracer_opts[] = { 45 /* Default disable the minimalistic output */ 46 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 47 { } 48 }; 49 50 static struct tracer_flags blk_tracer_flags = { 51 .val = 0, 52 .opts = blk_tracer_opts, 53 }; 54 55 /* Global reference count of probes */ 56 static atomic_t blk_probes_ref = ATOMIC_INIT(0); 57 58 static void blk_register_tracepoints(void); 59 static void blk_unregister_tracepoints(void); 60 61 /* 62 * Send out a notify message. 63 */ 64 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 65 const void *data, size_t len) 66 { 67 struct blk_io_trace *t; 68 struct ring_buffer_event *event = NULL; 69 struct ring_buffer *buffer = NULL; 70 int pc = 0; 71 int cpu = smp_processor_id(); 72 bool blk_tracer = blk_tracer_enabled; 73 74 if (blk_tracer) { 75 buffer = blk_tr->buffer; 76 pc = preempt_count(); 77 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 78 sizeof(*t) + len, 79 0, pc); 80 if (!event) 81 return; 82 t = ring_buffer_event_data(event); 83 goto record_it; 84 } 85 86 if (!bt->rchan) 87 return; 88 89 t = relay_reserve(bt->rchan, sizeof(*t) + len); 90 if (t) { 91 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 92 t->time = ktime_to_ns(ktime_get()); 93 record_it: 94 t->device = bt->dev; 95 t->action = action; 96 t->pid = pid; 97 t->cpu = cpu; 98 t->pdu_len = len; 99 memcpy((void *) t + sizeof(*t), data, len); 100 101 if (blk_tracer) 102 trace_buffer_unlock_commit(buffer, event, 0, pc); 103 } 104 } 105 106 /* 107 * Send out a notify for this process, if we haven't done so since a trace 108 * started 109 */ 110 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) 111 { 112 tsk->btrace_seq = blktrace_seq; 113 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm)); 114 } 115 116 static void trace_note_time(struct blk_trace *bt) 117 { 118 struct timespec now; 119 unsigned long flags; 120 u32 words[2]; 121 122 getnstimeofday(&now); 123 words[0] = now.tv_sec; 124 words[1] = now.tv_nsec; 125 126 local_irq_save(flags); 127 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); 128 local_irq_restore(flags); 129 } 130 131 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 132 { 133 int n; 134 va_list args; 135 unsigned long flags; 136 char *buf; 137 138 if (unlikely(bt->trace_state != Blktrace_running && 139 !blk_tracer_enabled)) 140 return; 141 142 local_irq_save(flags); 143 buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); 144 va_start(args, fmt); 145 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 146 va_end(args); 147 148 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); 149 local_irq_restore(flags); 150 } 151 EXPORT_SYMBOL_GPL(__trace_note_message); 152 153 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 154 pid_t pid) 155 { 156 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 157 return 1; 158 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 159 return 1; 160 if (bt->pid && pid != bt->pid) 161 return 1; 162 163 return 0; 164 } 165 166 /* 167 * Data direction bit lookup 168 */ 169 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 170 BLK_TC_ACT(BLK_TC_WRITE) }; 171 172 #define BLK_TC_HARDBARRIER BLK_TC_BARRIER 173 #define BLK_TC_RAHEAD BLK_TC_AHEAD 174 175 /* The ilog2() calls fall out because they're constant */ 176 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \ 177 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name)) 178 179 /* 180 * The worker for the various blk_add_trace*() types. Fills out a 181 * blk_io_trace structure and places it in a per-cpu subbuffer. 182 */ 183 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 184 int rw, u32 what, int error, int pdu_len, void *pdu_data) 185 { 186 struct task_struct *tsk = current; 187 struct ring_buffer_event *event = NULL; 188 struct ring_buffer *buffer = NULL; 189 struct blk_io_trace *t; 190 unsigned long flags = 0; 191 unsigned long *sequence; 192 pid_t pid; 193 int cpu, pc = 0; 194 bool blk_tracer = blk_tracer_enabled; 195 196 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 197 return; 198 199 what |= ddir_act[rw & WRITE]; 200 what |= MASK_TC_BIT(rw, HARDBARRIER); 201 what |= MASK_TC_BIT(rw, SYNC); 202 what |= MASK_TC_BIT(rw, RAHEAD); 203 what |= MASK_TC_BIT(rw, META); 204 what |= MASK_TC_BIT(rw, DISCARD); 205 206 pid = tsk->pid; 207 if (act_log_check(bt, what, sector, pid)) 208 return; 209 cpu = raw_smp_processor_id(); 210 211 if (blk_tracer) { 212 tracing_record_cmdline(current); 213 214 buffer = blk_tr->buffer; 215 pc = preempt_count(); 216 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 217 sizeof(*t) + pdu_len, 218 0, pc); 219 if (!event) 220 return; 221 t = ring_buffer_event_data(event); 222 goto record_it; 223 } 224 225 /* 226 * A word about the locking here - we disable interrupts to reserve 227 * some space in the relay per-cpu buffer, to prevent an irq 228 * from coming in and stepping on our toes. 229 */ 230 local_irq_save(flags); 231 232 if (unlikely(tsk->btrace_seq != blktrace_seq)) 233 trace_note_tsk(bt, tsk); 234 235 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 236 if (t) { 237 sequence = per_cpu_ptr(bt->sequence, cpu); 238 239 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 240 t->sequence = ++(*sequence); 241 t->time = ktime_to_ns(ktime_get()); 242 record_it: 243 /* 244 * These two are not needed in ftrace as they are in the 245 * generic trace_entry, filled by tracing_generic_entry_update, 246 * but for the trace_event->bin() synthesizer benefit we do it 247 * here too. 248 */ 249 t->cpu = cpu; 250 t->pid = pid; 251 252 t->sector = sector; 253 t->bytes = bytes; 254 t->action = what; 255 t->device = bt->dev; 256 t->error = error; 257 t->pdu_len = pdu_len; 258 259 if (pdu_len) 260 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 261 262 if (blk_tracer) { 263 trace_buffer_unlock_commit(buffer, event, 0, pc); 264 return; 265 } 266 } 267 268 local_irq_restore(flags); 269 } 270 271 static struct dentry *blk_tree_root; 272 static DEFINE_MUTEX(blk_tree_mutex); 273 274 static void blk_trace_free(struct blk_trace *bt) 275 { 276 debugfs_remove(bt->msg_file); 277 debugfs_remove(bt->dropped_file); 278 relay_close(bt->rchan); 279 debugfs_remove(bt->dir); 280 free_percpu(bt->sequence); 281 free_percpu(bt->msg_data); 282 kfree(bt); 283 } 284 285 static void blk_trace_cleanup(struct blk_trace *bt) 286 { 287 blk_trace_free(bt); 288 if (atomic_dec_and_test(&blk_probes_ref)) 289 blk_unregister_tracepoints(); 290 } 291 292 int blk_trace_remove(struct request_queue *q) 293 { 294 struct blk_trace *bt; 295 296 bt = xchg(&q->blk_trace, NULL); 297 if (!bt) 298 return -EINVAL; 299 300 if (bt->trace_state != Blktrace_running) 301 blk_trace_cleanup(bt); 302 303 return 0; 304 } 305 EXPORT_SYMBOL_GPL(blk_trace_remove); 306 307 static int blk_dropped_open(struct inode *inode, struct file *filp) 308 { 309 filp->private_data = inode->i_private; 310 311 return 0; 312 } 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 = blk_dropped_open, 328 .read = blk_dropped_read, 329 }; 330 331 static int blk_msg_open(struct inode *inode, struct file *filp) 332 { 333 filp->private_data = inode->i_private; 334 335 return 0; 336 } 337 338 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 339 size_t count, loff_t *ppos) 340 { 341 char *msg; 342 struct blk_trace *bt; 343 344 if (count >= BLK_TN_MAX_MSG) 345 return -EINVAL; 346 347 msg = kmalloc(count + 1, GFP_KERNEL); 348 if (msg == NULL) 349 return -ENOMEM; 350 351 if (copy_from_user(msg, buffer, count)) { 352 kfree(msg); 353 return -EFAULT; 354 } 355 356 msg[count] = '\0'; 357 bt = filp->private_data; 358 __trace_note_message(bt, "%s", msg); 359 kfree(msg); 360 361 return count; 362 } 363 364 static const struct file_operations blk_msg_fops = { 365 .owner = THIS_MODULE, 366 .open = blk_msg_open, 367 .write = blk_msg_write, 368 }; 369 370 /* 371 * Keep track of how many times we encountered a full subbuffer, to aid 372 * the user space app in telling how many lost events there were. 373 */ 374 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 375 void *prev_subbuf, size_t prev_padding) 376 { 377 struct blk_trace *bt; 378 379 if (!relay_buf_full(buf)) 380 return 1; 381 382 bt = buf->chan->private_data; 383 atomic_inc(&bt->dropped); 384 return 0; 385 } 386 387 static int blk_remove_buf_file_callback(struct dentry *dentry) 388 { 389 debugfs_remove(dentry); 390 391 return 0; 392 } 393 394 static struct dentry *blk_create_buf_file_callback(const char *filename, 395 struct dentry *parent, 396 int mode, 397 struct rchan_buf *buf, 398 int *is_global) 399 { 400 return debugfs_create_file(filename, mode, parent, buf, 401 &relay_file_operations); 402 } 403 404 static struct rchan_callbacks blk_relay_callbacks = { 405 .subbuf_start = blk_subbuf_start_callback, 406 .create_buf_file = blk_create_buf_file_callback, 407 .remove_buf_file = blk_remove_buf_file_callback, 408 }; 409 410 static void blk_trace_setup_lba(struct blk_trace *bt, 411 struct block_device *bdev) 412 { 413 struct hd_struct *part = NULL; 414 415 if (bdev) 416 part = bdev->bd_part; 417 418 if (part) { 419 bt->start_lba = part->start_sect; 420 bt->end_lba = part->start_sect + part->nr_sects; 421 } else { 422 bt->start_lba = 0; 423 bt->end_lba = -1ULL; 424 } 425 } 426 427 /* 428 * Setup everything required to start tracing 429 */ 430 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 431 struct block_device *bdev, 432 struct blk_user_trace_setup *buts) 433 { 434 struct blk_trace *old_bt, *bt = NULL; 435 struct dentry *dir = NULL; 436 int ret, i; 437 438 if (!buts->buf_size || !buts->buf_nr) 439 return -EINVAL; 440 441 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 442 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 443 444 /* 445 * some device names have larger paths - convert the slashes 446 * to underscores for this to work as expected 447 */ 448 for (i = 0; i < strlen(buts->name); i++) 449 if (buts->name[i] == '/') 450 buts->name[i] = '_'; 451 452 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 453 if (!bt) 454 return -ENOMEM; 455 456 ret = -ENOMEM; 457 bt->sequence = alloc_percpu(unsigned long); 458 if (!bt->sequence) 459 goto err; 460 461 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 462 if (!bt->msg_data) 463 goto err; 464 465 ret = -ENOENT; 466 467 mutex_lock(&blk_tree_mutex); 468 if (!blk_tree_root) { 469 blk_tree_root = debugfs_create_dir("block", NULL); 470 if (!blk_tree_root) { 471 mutex_unlock(&blk_tree_mutex); 472 goto err; 473 } 474 } 475 mutex_unlock(&blk_tree_mutex); 476 477 dir = debugfs_create_dir(buts->name, blk_tree_root); 478 479 if (!dir) 480 goto err; 481 482 bt->dir = dir; 483 bt->dev = dev; 484 atomic_set(&bt->dropped, 0); 485 486 ret = -EIO; 487 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 488 &blk_dropped_fops); 489 if (!bt->dropped_file) 490 goto err; 491 492 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 493 if (!bt->msg_file) 494 goto err; 495 496 bt->rchan = relay_open("trace", dir, buts->buf_size, 497 buts->buf_nr, &blk_relay_callbacks, bt); 498 if (!bt->rchan) 499 goto err; 500 501 bt->act_mask = buts->act_mask; 502 if (!bt->act_mask) 503 bt->act_mask = (u16) -1; 504 505 blk_trace_setup_lba(bt, bdev); 506 507 /* overwrite with user settings */ 508 if (buts->start_lba) 509 bt->start_lba = buts->start_lba; 510 if (buts->end_lba) 511 bt->end_lba = buts->end_lba; 512 513 bt->pid = buts->pid; 514 bt->trace_state = Blktrace_setup; 515 516 ret = -EBUSY; 517 old_bt = xchg(&q->blk_trace, bt); 518 if (old_bt) { 519 (void) xchg(&q->blk_trace, old_bt); 520 goto err; 521 } 522 523 if (atomic_inc_return(&blk_probes_ref) == 1) 524 blk_register_tracepoints(); 525 526 return 0; 527 err: 528 blk_trace_free(bt); 529 return ret; 530 } 531 532 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 533 struct block_device *bdev, 534 char __user *arg) 535 { 536 struct blk_user_trace_setup buts; 537 int ret; 538 539 ret = copy_from_user(&buts, arg, sizeof(buts)); 540 if (ret) 541 return -EFAULT; 542 543 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 544 if (ret) 545 return ret; 546 547 if (copy_to_user(arg, &buts, sizeof(buts))) { 548 blk_trace_remove(q); 549 return -EFAULT; 550 } 551 return 0; 552 } 553 EXPORT_SYMBOL_GPL(blk_trace_setup); 554 555 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 556 static int compat_blk_trace_setup(struct request_queue *q, char *name, 557 dev_t dev, struct block_device *bdev, 558 char __user *arg) 559 { 560 struct blk_user_trace_setup buts; 561 struct compat_blk_user_trace_setup cbuts; 562 int ret; 563 564 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 565 return -EFAULT; 566 567 buts = (struct blk_user_trace_setup) { 568 .act_mask = cbuts.act_mask, 569 .buf_size = cbuts.buf_size, 570 .buf_nr = cbuts.buf_nr, 571 .start_lba = cbuts.start_lba, 572 .end_lba = cbuts.end_lba, 573 .pid = cbuts.pid, 574 }; 575 memcpy(&buts.name, &cbuts.name, 32); 576 577 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 578 if (ret) 579 return ret; 580 581 if (copy_to_user(arg, &buts.name, 32)) { 582 blk_trace_remove(q); 583 return -EFAULT; 584 } 585 586 return 0; 587 } 588 #endif 589 590 int blk_trace_startstop(struct request_queue *q, int start) 591 { 592 int ret; 593 struct blk_trace *bt = q->blk_trace; 594 595 if (bt == NULL) 596 return -EINVAL; 597 598 /* 599 * For starting a trace, we can transition from a setup or stopped 600 * trace. For stopping a trace, the state must be running 601 */ 602 ret = -EINVAL; 603 if (start) { 604 if (bt->trace_state == Blktrace_setup || 605 bt->trace_state == Blktrace_stopped) { 606 blktrace_seq++; 607 smp_mb(); 608 bt->trace_state = Blktrace_running; 609 610 trace_note_time(bt); 611 ret = 0; 612 } 613 } else { 614 if (bt->trace_state == Blktrace_running) { 615 bt->trace_state = Blktrace_stopped; 616 relay_flush(bt->rchan); 617 ret = 0; 618 } 619 } 620 621 return ret; 622 } 623 EXPORT_SYMBOL_GPL(blk_trace_startstop); 624 625 /** 626 * blk_trace_ioctl: - handle the ioctls associated with tracing 627 * @bdev: the block device 628 * @cmd: the ioctl cmd 629 * @arg: the argument data, if any 630 * 631 **/ 632 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 633 { 634 struct request_queue *q; 635 int ret, start = 0; 636 char b[BDEVNAME_SIZE]; 637 638 q = bdev_get_queue(bdev); 639 if (!q) 640 return -ENXIO; 641 642 lock_kernel(); 643 mutex_lock(&bdev->bd_mutex); 644 645 switch (cmd) { 646 case BLKTRACESETUP: 647 bdevname(bdev, b); 648 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 649 break; 650 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 651 case BLKTRACESETUP32: 652 bdevname(bdev, b); 653 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 654 break; 655 #endif 656 case BLKTRACESTART: 657 start = 1; 658 case BLKTRACESTOP: 659 ret = blk_trace_startstop(q, start); 660 break; 661 case BLKTRACETEARDOWN: 662 ret = blk_trace_remove(q); 663 break; 664 default: 665 ret = -ENOTTY; 666 break; 667 } 668 669 mutex_unlock(&bdev->bd_mutex); 670 unlock_kernel(); 671 return ret; 672 } 673 674 /** 675 * blk_trace_shutdown: - stop and cleanup trace structures 676 * @q: the request queue associated with the device 677 * 678 **/ 679 void blk_trace_shutdown(struct request_queue *q) 680 { 681 if (q->blk_trace) { 682 blk_trace_startstop(q, 0); 683 blk_trace_remove(q); 684 } 685 } 686 687 /* 688 * blktrace probes 689 */ 690 691 /** 692 * blk_add_trace_rq - Add a trace for a request oriented action 693 * @q: queue the io is for 694 * @rq: the source request 695 * @what: the action 696 * 697 * Description: 698 * Records an action against a request. Will log the bio offset + size. 699 * 700 **/ 701 static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 702 u32 what) 703 { 704 struct blk_trace *bt = q->blk_trace; 705 int rw = rq->cmd_flags & 0x03; 706 707 if (likely(!bt)) 708 return; 709 710 if (rq->cmd_flags & REQ_DISCARD) 711 rw |= REQ_DISCARD; 712 713 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { 714 what |= BLK_TC_ACT(BLK_TC_PC); 715 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw, 716 what, rq->errors, rq->cmd_len, rq->cmd); 717 } else { 718 what |= BLK_TC_ACT(BLK_TC_FS); 719 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw, 720 what, rq->errors, 0, NULL); 721 } 722 } 723 724 static void blk_add_trace_rq_abort(void *ignore, 725 struct request_queue *q, struct request *rq) 726 { 727 blk_add_trace_rq(q, rq, BLK_TA_ABORT); 728 } 729 730 static void blk_add_trace_rq_insert(void *ignore, 731 struct request_queue *q, struct request *rq) 732 { 733 blk_add_trace_rq(q, rq, BLK_TA_INSERT); 734 } 735 736 static void blk_add_trace_rq_issue(void *ignore, 737 struct request_queue *q, struct request *rq) 738 { 739 blk_add_trace_rq(q, rq, BLK_TA_ISSUE); 740 } 741 742 static void blk_add_trace_rq_requeue(void *ignore, 743 struct request_queue *q, 744 struct request *rq) 745 { 746 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); 747 } 748 749 static void blk_add_trace_rq_complete(void *ignore, 750 struct request_queue *q, 751 struct request *rq) 752 { 753 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE); 754 } 755 756 /** 757 * blk_add_trace_bio - Add a trace for a bio oriented action 758 * @q: queue the io is for 759 * @bio: the source bio 760 * @what: the action 761 * 762 * Description: 763 * Records an action against a bio. Will log the bio offset + size. 764 * 765 **/ 766 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 767 u32 what) 768 { 769 struct blk_trace *bt = q->blk_trace; 770 771 if (likely(!bt)) 772 return; 773 774 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, 775 !bio_flagged(bio, BIO_UPTODATE), 0, NULL); 776 } 777 778 static void blk_add_trace_bio_bounce(void *ignore, 779 struct request_queue *q, struct bio *bio) 780 { 781 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE); 782 } 783 784 static void blk_add_trace_bio_complete(void *ignore, 785 struct request_queue *q, struct bio *bio) 786 { 787 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE); 788 } 789 790 static void blk_add_trace_bio_backmerge(void *ignore, 791 struct request_queue *q, 792 struct bio *bio) 793 { 794 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE); 795 } 796 797 static void blk_add_trace_bio_frontmerge(void *ignore, 798 struct request_queue *q, 799 struct bio *bio) 800 { 801 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE); 802 } 803 804 static void blk_add_trace_bio_queue(void *ignore, 805 struct request_queue *q, struct bio *bio) 806 { 807 blk_add_trace_bio(q, bio, BLK_TA_QUEUE); 808 } 809 810 static void blk_add_trace_getrq(void *ignore, 811 struct request_queue *q, 812 struct bio *bio, int rw) 813 { 814 if (bio) 815 blk_add_trace_bio(q, bio, BLK_TA_GETRQ); 816 else { 817 struct blk_trace *bt = q->blk_trace; 818 819 if (bt) 820 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); 821 } 822 } 823 824 825 static void blk_add_trace_sleeprq(void *ignore, 826 struct request_queue *q, 827 struct bio *bio, int rw) 828 { 829 if (bio) 830 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ); 831 else { 832 struct blk_trace *bt = q->blk_trace; 833 834 if (bt) 835 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 836 0, 0, NULL); 837 } 838 } 839 840 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 841 { 842 struct blk_trace *bt = q->blk_trace; 843 844 if (bt) 845 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 846 } 847 848 static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q) 849 { 850 struct blk_trace *bt = q->blk_trace; 851 852 if (bt) { 853 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 854 __be64 rpdu = cpu_to_be64(pdu); 855 856 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0, 857 sizeof(rpdu), &rpdu); 858 } 859 } 860 861 static void blk_add_trace_unplug_timer(void *ignore, struct request_queue *q) 862 { 863 struct blk_trace *bt = q->blk_trace; 864 865 if (bt) { 866 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 867 __be64 rpdu = cpu_to_be64(pdu); 868 869 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0, 870 sizeof(rpdu), &rpdu); 871 } 872 } 873 874 static void blk_add_trace_split(void *ignore, 875 struct request_queue *q, struct bio *bio, 876 unsigned int pdu) 877 { 878 struct blk_trace *bt = q->blk_trace; 879 880 if (bt) { 881 __be64 rpdu = cpu_to_be64(pdu); 882 883 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 884 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE), 885 sizeof(rpdu), &rpdu); 886 } 887 } 888 889 /** 890 * blk_add_trace_remap - Add a trace for a remap operation 891 * @ignore: trace callback data parameter (not used) 892 * @q: queue the io is for 893 * @bio: the source bio 894 * @dev: target device 895 * @from: source sector 896 * 897 * Description: 898 * Device mapper or raid target sometimes need to split a bio because 899 * it spans a stripe (or similar). Add a trace for that action. 900 * 901 **/ 902 static void blk_add_trace_remap(void *ignore, 903 struct request_queue *q, struct bio *bio, 904 dev_t dev, sector_t from) 905 { 906 struct blk_trace *bt = q->blk_trace; 907 struct blk_io_trace_remap r; 908 909 if (likely(!bt)) 910 return; 911 912 r.device_from = cpu_to_be32(dev); 913 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 914 r.sector_from = cpu_to_be64(from); 915 916 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 917 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), 918 sizeof(r), &r); 919 } 920 921 /** 922 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 923 * @ignore: trace callback data parameter (not used) 924 * @q: queue the io is for 925 * @rq: the source request 926 * @dev: target device 927 * @from: source sector 928 * 929 * Description: 930 * Device mapper remaps request to other devices. 931 * Add a trace for that action. 932 * 933 **/ 934 static void blk_add_trace_rq_remap(void *ignore, 935 struct request_queue *q, 936 struct request *rq, dev_t dev, 937 sector_t from) 938 { 939 struct blk_trace *bt = q->blk_trace; 940 struct blk_io_trace_remap r; 941 942 if (likely(!bt)) 943 return; 944 945 r.device_from = cpu_to_be32(dev); 946 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 947 r.sector_from = cpu_to_be64(from); 948 949 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 950 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors, 951 sizeof(r), &r); 952 } 953 954 /** 955 * blk_add_driver_data - Add binary message with driver-specific data 956 * @q: queue the io is for 957 * @rq: io request 958 * @data: driver-specific data 959 * @len: length of driver-specific data 960 * 961 * Description: 962 * Some drivers might want to write driver-specific data per request. 963 * 964 **/ 965 void blk_add_driver_data(struct request_queue *q, 966 struct request *rq, 967 void *data, size_t len) 968 { 969 struct blk_trace *bt = q->blk_trace; 970 971 if (likely(!bt)) 972 return; 973 974 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) 975 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 976 BLK_TA_DRV_DATA, rq->errors, len, data); 977 else 978 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 979 BLK_TA_DRV_DATA, rq->errors, len, data); 980 } 981 EXPORT_SYMBOL_GPL(blk_add_driver_data); 982 983 static void blk_register_tracepoints(void) 984 { 985 int ret; 986 987 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 988 WARN_ON(ret); 989 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 990 WARN_ON(ret); 991 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 992 WARN_ON(ret); 993 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 994 WARN_ON(ret); 995 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 996 WARN_ON(ret); 997 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 998 WARN_ON(ret); 999 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1000 WARN_ON(ret); 1001 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1002 WARN_ON(ret); 1003 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1004 WARN_ON(ret); 1005 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1006 WARN_ON(ret); 1007 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 1008 WARN_ON(ret); 1009 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1010 WARN_ON(ret); 1011 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 1012 WARN_ON(ret); 1013 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL); 1014 WARN_ON(ret); 1015 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, 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_remap(blk_add_trace_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_remap(blk_add_trace_remap, NULL); 1029 unregister_trace_block_split(blk_add_trace_split, NULL); 1030 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); 1031 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL); 1032 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1033 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1034 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1035 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1036 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1037 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1038 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1039 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1040 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1041 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1042 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1043 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1044 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 1045 1046 tracepoint_synchronize_unregister(); 1047 } 1048 1049 /* 1050 * struct blk_io_tracer formatting routines 1051 */ 1052 1053 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1054 { 1055 int i = 0; 1056 int tc = t->action >> BLK_TC_SHIFT; 1057 1058 if (t->action == BLK_TN_MESSAGE) { 1059 rwbs[i++] = 'N'; 1060 goto out; 1061 } 1062 1063 if (tc & BLK_TC_DISCARD) 1064 rwbs[i++] = 'D'; 1065 else if (tc & BLK_TC_WRITE) 1066 rwbs[i++] = 'W'; 1067 else if (t->bytes) 1068 rwbs[i++] = 'R'; 1069 else 1070 rwbs[i++] = 'N'; 1071 1072 if (tc & BLK_TC_AHEAD) 1073 rwbs[i++] = 'A'; 1074 if (tc & BLK_TC_BARRIER) 1075 rwbs[i++] = 'B'; 1076 if (tc & BLK_TC_SYNC) 1077 rwbs[i++] = 'S'; 1078 if (tc & BLK_TC_META) 1079 rwbs[i++] = 'M'; 1080 out: 1081 rwbs[i] = '\0'; 1082 } 1083 1084 static inline 1085 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1086 { 1087 return (const struct blk_io_trace *)ent; 1088 } 1089 1090 static inline const void *pdu_start(const struct trace_entry *ent) 1091 { 1092 return te_blk_io_trace(ent) + 1; 1093 } 1094 1095 static inline u32 t_action(const struct trace_entry *ent) 1096 { 1097 return te_blk_io_trace(ent)->action; 1098 } 1099 1100 static inline u32 t_bytes(const struct trace_entry *ent) 1101 { 1102 return te_blk_io_trace(ent)->bytes; 1103 } 1104 1105 static inline u32 t_sec(const struct trace_entry *ent) 1106 { 1107 return te_blk_io_trace(ent)->bytes >> 9; 1108 } 1109 1110 static inline unsigned long long t_sector(const struct trace_entry *ent) 1111 { 1112 return te_blk_io_trace(ent)->sector; 1113 } 1114 1115 static inline __u16 t_error(const struct trace_entry *ent) 1116 { 1117 return te_blk_io_trace(ent)->error; 1118 } 1119 1120 static __u64 get_pdu_int(const struct trace_entry *ent) 1121 { 1122 const __u64 *val = pdu_start(ent); 1123 return be64_to_cpu(*val); 1124 } 1125 1126 static void get_pdu_remap(const struct trace_entry *ent, 1127 struct blk_io_trace_remap *r) 1128 { 1129 const struct blk_io_trace_remap *__r = pdu_start(ent); 1130 __u64 sector_from = __r->sector_from; 1131 1132 r->device_from = be32_to_cpu(__r->device_from); 1133 r->device_to = be32_to_cpu(__r->device_to); 1134 r->sector_from = be64_to_cpu(sector_from); 1135 } 1136 1137 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1138 1139 static int blk_log_action_classic(struct trace_iterator *iter, const char *act) 1140 { 1141 char rwbs[6]; 1142 unsigned long long ts = iter->ts; 1143 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1144 unsigned secs = (unsigned long)ts; 1145 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1146 1147 fill_rwbs(rwbs, t); 1148 1149 return trace_seq_printf(&iter->seq, 1150 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1151 MAJOR(t->device), MINOR(t->device), iter->cpu, 1152 secs, nsec_rem, iter->ent->pid, act, rwbs); 1153 } 1154 1155 static int blk_log_action(struct trace_iterator *iter, const char *act) 1156 { 1157 char rwbs[6]; 1158 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1159 1160 fill_rwbs(rwbs, t); 1161 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1162 MAJOR(t->device), MINOR(t->device), act, rwbs); 1163 } 1164 1165 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1166 { 1167 const unsigned char *pdu_buf; 1168 int pdu_len; 1169 int i, end, ret; 1170 1171 pdu_buf = pdu_start(ent); 1172 pdu_len = te_blk_io_trace(ent)->pdu_len; 1173 1174 if (!pdu_len) 1175 return 1; 1176 1177 /* find the last zero that needs to be printed */ 1178 for (end = pdu_len - 1; end >= 0; end--) 1179 if (pdu_buf[end]) 1180 break; 1181 end++; 1182 1183 if (!trace_seq_putc(s, '(')) 1184 return 0; 1185 1186 for (i = 0; i < pdu_len; i++) { 1187 1188 ret = trace_seq_printf(s, "%s%02x", 1189 i == 0 ? "" : " ", pdu_buf[i]); 1190 if (!ret) 1191 return ret; 1192 1193 /* 1194 * stop when the rest is just zeroes and indicate so 1195 * with a ".." appended 1196 */ 1197 if (i == end && end != pdu_len - 1) 1198 return trace_seq_puts(s, " ..) "); 1199 } 1200 1201 return trace_seq_puts(s, ") "); 1202 } 1203 1204 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1205 { 1206 char cmd[TASK_COMM_LEN]; 1207 1208 trace_find_cmdline(ent->pid, cmd); 1209 1210 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1211 int ret; 1212 1213 ret = trace_seq_printf(s, "%u ", t_bytes(ent)); 1214 if (!ret) 1215 return 0; 1216 ret = blk_log_dump_pdu(s, ent); 1217 if (!ret) 1218 return 0; 1219 return trace_seq_printf(s, "[%s]\n", cmd); 1220 } else { 1221 if (t_sec(ent)) 1222 return trace_seq_printf(s, "%llu + %u [%s]\n", 1223 t_sector(ent), t_sec(ent), cmd); 1224 return trace_seq_printf(s, "[%s]\n", cmd); 1225 } 1226 } 1227 1228 static int blk_log_with_error(struct trace_seq *s, 1229 const struct trace_entry *ent) 1230 { 1231 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1232 int ret; 1233 1234 ret = blk_log_dump_pdu(s, ent); 1235 if (ret) 1236 return trace_seq_printf(s, "[%d]\n", t_error(ent)); 1237 return 0; 1238 } else { 1239 if (t_sec(ent)) 1240 return trace_seq_printf(s, "%llu + %u [%d]\n", 1241 t_sector(ent), 1242 t_sec(ent), t_error(ent)); 1243 return trace_seq_printf(s, "%llu [%d]\n", 1244 t_sector(ent), t_error(ent)); 1245 } 1246 } 1247 1248 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1249 { 1250 struct blk_io_trace_remap r = { .device_from = 0, }; 1251 1252 get_pdu_remap(ent, &r); 1253 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1254 t_sector(ent), t_sec(ent), 1255 MAJOR(r.device_from), MINOR(r.device_from), 1256 (unsigned long long)r.sector_from); 1257 } 1258 1259 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1260 { 1261 char cmd[TASK_COMM_LEN]; 1262 1263 trace_find_cmdline(ent->pid, cmd); 1264 1265 return trace_seq_printf(s, "[%s]\n", cmd); 1266 } 1267 1268 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1269 { 1270 char cmd[TASK_COMM_LEN]; 1271 1272 trace_find_cmdline(ent->pid, cmd); 1273 1274 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1275 } 1276 1277 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1278 { 1279 char cmd[TASK_COMM_LEN]; 1280 1281 trace_find_cmdline(ent->pid, cmd); 1282 1283 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1284 get_pdu_int(ent), cmd); 1285 } 1286 1287 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1288 { 1289 int ret; 1290 const struct blk_io_trace *t = te_blk_io_trace(ent); 1291 1292 ret = trace_seq_putmem(s, t + 1, t->pdu_len); 1293 if (ret) 1294 return trace_seq_putc(s, '\n'); 1295 return ret; 1296 } 1297 1298 /* 1299 * struct tracer operations 1300 */ 1301 1302 static void blk_tracer_print_header(struct seq_file *m) 1303 { 1304 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1305 return; 1306 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1307 "# | | | | | |\n"); 1308 } 1309 1310 static void blk_tracer_start(struct trace_array *tr) 1311 { 1312 blk_tracer_enabled = true; 1313 } 1314 1315 static int blk_tracer_init(struct trace_array *tr) 1316 { 1317 blk_tr = tr; 1318 blk_tracer_start(tr); 1319 return 0; 1320 } 1321 1322 static void blk_tracer_stop(struct trace_array *tr) 1323 { 1324 blk_tracer_enabled = false; 1325 } 1326 1327 static void blk_tracer_reset(struct trace_array *tr) 1328 { 1329 blk_tracer_stop(tr); 1330 } 1331 1332 static const struct { 1333 const char *act[2]; 1334 int (*print)(struct trace_seq *s, const struct trace_entry *ent); 1335 } what2act[] = { 1336 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1337 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1338 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1339 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1340 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1341 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1342 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1343 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1344 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1345 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1346 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1347 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1348 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1349 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1350 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1351 }; 1352 1353 static enum print_line_t print_one_line(struct trace_iterator *iter, 1354 bool classic) 1355 { 1356 struct trace_seq *s = &iter->seq; 1357 const struct blk_io_trace *t; 1358 u16 what; 1359 int ret; 1360 bool long_act; 1361 blk_log_action_t *log_action; 1362 1363 t = te_blk_io_trace(iter->ent); 1364 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1365 long_act = !!(trace_flags & TRACE_ITER_VERBOSE); 1366 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1367 1368 if (t->action == BLK_TN_MESSAGE) { 1369 ret = log_action(iter, long_act ? "message" : "m"); 1370 if (ret) 1371 ret = blk_log_msg(s, iter->ent); 1372 goto out; 1373 } 1374 1375 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1376 ret = trace_seq_printf(s, "Unknown action %x\n", what); 1377 else { 1378 ret = log_action(iter, what2act[what].act[long_act]); 1379 if (ret) 1380 ret = what2act[what].print(s, iter->ent); 1381 } 1382 out: 1383 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1384 } 1385 1386 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1387 int flags, struct trace_event *event) 1388 { 1389 return print_one_line(iter, false); 1390 } 1391 1392 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1393 { 1394 struct trace_seq *s = &iter->seq; 1395 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1396 const int offset = offsetof(struct blk_io_trace, sector); 1397 struct blk_io_trace old = { 1398 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1399 .time = iter->ts, 1400 }; 1401 1402 if (!trace_seq_putmem(s, &old, offset)) 1403 return 0; 1404 return trace_seq_putmem(s, &t->sector, 1405 sizeof(old) - offset + t->pdu_len); 1406 } 1407 1408 static enum print_line_t 1409 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1410 struct trace_event *event) 1411 { 1412 return blk_trace_synthesize_old_trace(iter) ? 1413 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1414 } 1415 1416 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1417 { 1418 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1419 return TRACE_TYPE_UNHANDLED; 1420 1421 return print_one_line(iter, true); 1422 } 1423 1424 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set) 1425 { 1426 /* don't output context-info for blk_classic output */ 1427 if (bit == TRACE_BLK_OPT_CLASSIC) { 1428 if (set) 1429 trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1430 else 1431 trace_flags |= TRACE_ITER_CONTEXT_INFO; 1432 } 1433 return 0; 1434 } 1435 1436 static struct tracer blk_tracer __read_mostly = { 1437 .name = "blk", 1438 .init = blk_tracer_init, 1439 .reset = blk_tracer_reset, 1440 .start = blk_tracer_start, 1441 .stop = blk_tracer_stop, 1442 .print_header = blk_tracer_print_header, 1443 .print_line = blk_tracer_print_line, 1444 .flags = &blk_tracer_flags, 1445 .set_flag = blk_tracer_set_flag, 1446 }; 1447 1448 static struct trace_event_functions trace_blk_event_funcs = { 1449 .trace = blk_trace_event_print, 1450 .binary = blk_trace_event_print_binary, 1451 }; 1452 1453 static struct trace_event trace_blk_event = { 1454 .type = TRACE_BLK, 1455 .funcs = &trace_blk_event_funcs, 1456 }; 1457 1458 static int __init init_blk_tracer(void) 1459 { 1460 if (!register_ftrace_event(&trace_blk_event)) { 1461 pr_warning("Warning: could not register block events\n"); 1462 return 1; 1463 } 1464 1465 if (register_tracer(&blk_tracer) != 0) { 1466 pr_warning("Warning: could not register the block tracer\n"); 1467 unregister_ftrace_event(&trace_blk_event); 1468 return 1; 1469 } 1470 1471 return 0; 1472 } 1473 1474 device_initcall(init_blk_tracer); 1475 1476 static int blk_trace_remove_queue(struct request_queue *q) 1477 { 1478 struct blk_trace *bt; 1479 1480 bt = xchg(&q->blk_trace, NULL); 1481 if (bt == NULL) 1482 return -EINVAL; 1483 1484 if (atomic_dec_and_test(&blk_probes_ref)) 1485 blk_unregister_tracepoints(); 1486 1487 blk_trace_free(bt); 1488 return 0; 1489 } 1490 1491 /* 1492 * Setup everything required to start tracing 1493 */ 1494 static int blk_trace_setup_queue(struct request_queue *q, 1495 struct block_device *bdev) 1496 { 1497 struct blk_trace *old_bt, *bt = NULL; 1498 int ret = -ENOMEM; 1499 1500 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1501 if (!bt) 1502 return -ENOMEM; 1503 1504 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1505 if (!bt->msg_data) 1506 goto free_bt; 1507 1508 bt->dev = bdev->bd_dev; 1509 bt->act_mask = (u16)-1; 1510 1511 blk_trace_setup_lba(bt, bdev); 1512 1513 old_bt = xchg(&q->blk_trace, bt); 1514 if (old_bt != NULL) { 1515 (void)xchg(&q->blk_trace, old_bt); 1516 ret = -EBUSY; 1517 goto free_bt; 1518 } 1519 1520 if (atomic_inc_return(&blk_probes_ref) == 1) 1521 blk_register_tracepoints(); 1522 return 0; 1523 1524 free_bt: 1525 blk_trace_free(bt); 1526 return ret; 1527 } 1528 1529 /* 1530 * sysfs interface to enable and configure tracing 1531 */ 1532 1533 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1534 struct device_attribute *attr, 1535 char *buf); 1536 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1537 struct device_attribute *attr, 1538 const char *buf, size_t count); 1539 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1540 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1541 sysfs_blk_trace_attr_show, \ 1542 sysfs_blk_trace_attr_store) 1543 1544 static BLK_TRACE_DEVICE_ATTR(enable); 1545 static BLK_TRACE_DEVICE_ATTR(act_mask); 1546 static BLK_TRACE_DEVICE_ATTR(pid); 1547 static BLK_TRACE_DEVICE_ATTR(start_lba); 1548 static BLK_TRACE_DEVICE_ATTR(end_lba); 1549 1550 static struct attribute *blk_trace_attrs[] = { 1551 &dev_attr_enable.attr, 1552 &dev_attr_act_mask.attr, 1553 &dev_attr_pid.attr, 1554 &dev_attr_start_lba.attr, 1555 &dev_attr_end_lba.attr, 1556 NULL 1557 }; 1558 1559 struct attribute_group blk_trace_attr_group = { 1560 .name = "trace", 1561 .attrs = blk_trace_attrs, 1562 }; 1563 1564 static const struct { 1565 int mask; 1566 const char *str; 1567 } mask_maps[] = { 1568 { BLK_TC_READ, "read" }, 1569 { BLK_TC_WRITE, "write" }, 1570 { BLK_TC_BARRIER, "barrier" }, 1571 { BLK_TC_SYNC, "sync" }, 1572 { BLK_TC_QUEUE, "queue" }, 1573 { BLK_TC_REQUEUE, "requeue" }, 1574 { BLK_TC_ISSUE, "issue" }, 1575 { BLK_TC_COMPLETE, "complete" }, 1576 { BLK_TC_FS, "fs" }, 1577 { BLK_TC_PC, "pc" }, 1578 { BLK_TC_AHEAD, "ahead" }, 1579 { BLK_TC_META, "meta" }, 1580 { BLK_TC_DISCARD, "discard" }, 1581 { BLK_TC_DRV_DATA, "drv_data" }, 1582 }; 1583 1584 static int blk_trace_str2mask(const char *str) 1585 { 1586 int i; 1587 int mask = 0; 1588 char *buf, *s, *token; 1589 1590 buf = kstrdup(str, GFP_KERNEL); 1591 if (buf == NULL) 1592 return -ENOMEM; 1593 s = strstrip(buf); 1594 1595 while (1) { 1596 token = strsep(&s, ","); 1597 if (token == NULL) 1598 break; 1599 1600 if (*token == '\0') 1601 continue; 1602 1603 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1604 if (strcasecmp(token, mask_maps[i].str) == 0) { 1605 mask |= mask_maps[i].mask; 1606 break; 1607 } 1608 } 1609 if (i == ARRAY_SIZE(mask_maps)) { 1610 mask = -EINVAL; 1611 break; 1612 } 1613 } 1614 kfree(buf); 1615 1616 return mask; 1617 } 1618 1619 static ssize_t blk_trace_mask2str(char *buf, int mask) 1620 { 1621 int i; 1622 char *p = buf; 1623 1624 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1625 if (mask & mask_maps[i].mask) { 1626 p += sprintf(p, "%s%s", 1627 (p == buf) ? "" : ",", mask_maps[i].str); 1628 } 1629 } 1630 *p++ = '\n'; 1631 1632 return p - buf; 1633 } 1634 1635 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1636 { 1637 if (bdev->bd_disk == NULL) 1638 return NULL; 1639 1640 return bdev_get_queue(bdev); 1641 } 1642 1643 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1644 struct device_attribute *attr, 1645 char *buf) 1646 { 1647 struct hd_struct *p = dev_to_part(dev); 1648 struct request_queue *q; 1649 struct block_device *bdev; 1650 ssize_t ret = -ENXIO; 1651 1652 lock_kernel(); 1653 bdev = bdget(part_devt(p)); 1654 if (bdev == NULL) 1655 goto out_unlock_kernel; 1656 1657 q = blk_trace_get_queue(bdev); 1658 if (q == NULL) 1659 goto out_bdput; 1660 1661 mutex_lock(&bdev->bd_mutex); 1662 1663 if (attr == &dev_attr_enable) { 1664 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1665 goto out_unlock_bdev; 1666 } 1667 1668 if (q->blk_trace == NULL) 1669 ret = sprintf(buf, "disabled\n"); 1670 else if (attr == &dev_attr_act_mask) 1671 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1672 else if (attr == &dev_attr_pid) 1673 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1674 else if (attr == &dev_attr_start_lba) 1675 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1676 else if (attr == &dev_attr_end_lba) 1677 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1678 1679 out_unlock_bdev: 1680 mutex_unlock(&bdev->bd_mutex); 1681 out_bdput: 1682 bdput(bdev); 1683 out_unlock_kernel: 1684 unlock_kernel(); 1685 return ret; 1686 } 1687 1688 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1689 struct device_attribute *attr, 1690 const char *buf, size_t count) 1691 { 1692 struct block_device *bdev; 1693 struct request_queue *q; 1694 struct hd_struct *p; 1695 u64 value; 1696 ssize_t ret = -EINVAL; 1697 1698 if (count == 0) 1699 goto out; 1700 1701 if (attr == &dev_attr_act_mask) { 1702 if (sscanf(buf, "%llx", &value) != 1) { 1703 /* Assume it is a list of trace category names */ 1704 ret = blk_trace_str2mask(buf); 1705 if (ret < 0) 1706 goto out; 1707 value = ret; 1708 } 1709 } else if (sscanf(buf, "%llu", &value) != 1) 1710 goto out; 1711 1712 ret = -ENXIO; 1713 1714 lock_kernel(); 1715 p = dev_to_part(dev); 1716 bdev = bdget(part_devt(p)); 1717 if (bdev == NULL) 1718 goto out_unlock_kernel; 1719 1720 q = blk_trace_get_queue(bdev); 1721 if (q == NULL) 1722 goto out_bdput; 1723 1724 mutex_lock(&bdev->bd_mutex); 1725 1726 if (attr == &dev_attr_enable) { 1727 if (value) 1728 ret = blk_trace_setup_queue(q, bdev); 1729 else 1730 ret = blk_trace_remove_queue(q); 1731 goto out_unlock_bdev; 1732 } 1733 1734 ret = 0; 1735 if (q->blk_trace == NULL) 1736 ret = blk_trace_setup_queue(q, bdev); 1737 1738 if (ret == 0) { 1739 if (attr == &dev_attr_act_mask) 1740 q->blk_trace->act_mask = value; 1741 else if (attr == &dev_attr_pid) 1742 q->blk_trace->pid = value; 1743 else if (attr == &dev_attr_start_lba) 1744 q->blk_trace->start_lba = value; 1745 else if (attr == &dev_attr_end_lba) 1746 q->blk_trace->end_lba = value; 1747 } 1748 1749 out_unlock_bdev: 1750 mutex_unlock(&bdev->bd_mutex); 1751 out_bdput: 1752 bdput(bdev); 1753 out_unlock_kernel: 1754 unlock_kernel(); 1755 out: 1756 return ret ? ret : count; 1757 } 1758 1759 int blk_trace_init_sysfs(struct device *dev) 1760 { 1761 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1762 } 1763 1764 void blk_trace_remove_sysfs(struct device *dev) 1765 { 1766 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1767 } 1768 1769 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1770 1771 #ifdef CONFIG_EVENT_TRACING 1772 1773 void blk_dump_cmd(char *buf, struct request *rq) 1774 { 1775 int i, end; 1776 int len = rq->cmd_len; 1777 unsigned char *cmd = rq->cmd; 1778 1779 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) { 1780 buf[0] = '\0'; 1781 return; 1782 } 1783 1784 for (end = len - 1; end >= 0; end--) 1785 if (cmd[end]) 1786 break; 1787 end++; 1788 1789 for (i = 0; i < len; i++) { 1790 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1791 if (i == end && end != len - 1) { 1792 sprintf(buf, " .."); 1793 break; 1794 } 1795 } 1796 } 1797 1798 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) 1799 { 1800 int i = 0; 1801 1802 if (rw & WRITE) 1803 rwbs[i++] = 'W'; 1804 else if (rw & REQ_DISCARD) 1805 rwbs[i++] = 'D'; 1806 else if (bytes) 1807 rwbs[i++] = 'R'; 1808 else 1809 rwbs[i++] = 'N'; 1810 1811 if (rw & REQ_RAHEAD) 1812 rwbs[i++] = 'A'; 1813 if (rw & REQ_HARDBARRIER) 1814 rwbs[i++] = 'B'; 1815 if (rw & REQ_SYNC) 1816 rwbs[i++] = 'S'; 1817 if (rw & REQ_META) 1818 rwbs[i++] = 'M'; 1819 1820 rwbs[i] = '\0'; 1821 } 1822 1823 void blk_fill_rwbs_rq(char *rwbs, struct request *rq) 1824 { 1825 int rw = rq->cmd_flags & 0x03; 1826 int bytes; 1827 1828 if (rq->cmd_flags & REQ_DISCARD) 1829 rw |= REQ_DISCARD; 1830 1831 bytes = blk_rq_bytes(rq); 1832 1833 blk_fill_rwbs(rwbs, rw, bytes); 1834 } 1835 1836 #endif /* CONFIG_EVENT_TRACING */ 1837 1838