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/time.h> 27 #include <linux/uaccess.h> 28 29 #include <trace/events/block.h> 30 31 #include "trace_output.h" 32 33 #ifdef CONFIG_BLK_DEV_IO_TRACE 34 35 static unsigned int blktrace_seq __read_mostly = 1; 36 37 static struct trace_array *blk_tr; 38 static bool blk_tracer_enabled __read_mostly; 39 40 /* Select an alternative, minimalistic output than the original one */ 41 #define TRACE_BLK_OPT_CLASSIC 0x1 42 43 static struct tracer_opt blk_tracer_opts[] = { 44 /* Default disable the minimalistic output */ 45 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 46 { } 47 }; 48 49 static struct tracer_flags blk_tracer_flags = { 50 .val = 0, 51 .opts = blk_tracer_opts, 52 }; 53 54 /* Global reference count of probes */ 55 static atomic_t blk_probes_ref = ATOMIC_INIT(0); 56 57 static void blk_register_tracepoints(void); 58 static void blk_unregister_tracepoints(void); 59 60 /* 61 * Send out a notify message. 62 */ 63 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 64 const void *data, size_t len) 65 { 66 struct blk_io_trace *t; 67 struct ring_buffer_event *event = NULL; 68 struct ring_buffer *buffer = NULL; 69 int pc = 0; 70 int cpu = smp_processor_id(); 71 bool blk_tracer = blk_tracer_enabled; 72 73 if (blk_tracer) { 74 buffer = blk_tr->buffer; 75 pc = preempt_count(); 76 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 77 sizeof(*t) + len, 78 0, pc); 79 if (!event) 80 return; 81 t = ring_buffer_event_data(event); 82 goto record_it; 83 } 84 85 if (!bt->rchan) 86 return; 87 88 t = relay_reserve(bt->rchan, sizeof(*t) + len); 89 if (t) { 90 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 91 t->time = ktime_to_ns(ktime_get()); 92 record_it: 93 t->device = bt->dev; 94 t->action = action; 95 t->pid = pid; 96 t->cpu = cpu; 97 t->pdu_len = len; 98 memcpy((void *) t + sizeof(*t), data, len); 99 100 if (blk_tracer) 101 trace_buffer_unlock_commit(buffer, event, 0, pc); 102 } 103 } 104 105 /* 106 * Send out a notify for this process, if we haven't done so since a trace 107 * started 108 */ 109 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) 110 { 111 tsk->btrace_seq = blktrace_seq; 112 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm)); 113 } 114 115 static void trace_note_time(struct blk_trace *bt) 116 { 117 struct timespec now; 118 unsigned long flags; 119 u32 words[2]; 120 121 getnstimeofday(&now); 122 words[0] = now.tv_sec; 123 words[1] = now.tv_nsec; 124 125 local_irq_save(flags); 126 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); 127 local_irq_restore(flags); 128 } 129 130 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 131 { 132 int n; 133 va_list args; 134 unsigned long flags; 135 char *buf; 136 137 if (unlikely(bt->trace_state != Blktrace_running && 138 !blk_tracer_enabled)) 139 return; 140 141 local_irq_save(flags); 142 buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); 143 va_start(args, fmt); 144 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 145 va_end(args); 146 147 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); 148 local_irq_restore(flags); 149 } 150 EXPORT_SYMBOL_GPL(__trace_note_message); 151 152 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 153 pid_t pid) 154 { 155 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 156 return 1; 157 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 158 return 1; 159 if (bt->pid && pid != bt->pid) 160 return 1; 161 162 return 0; 163 } 164 165 /* 166 * Data direction bit lookup 167 */ 168 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 169 BLK_TC_ACT(BLK_TC_WRITE) }; 170 171 #define BLK_TC_RAHEAD BLK_TC_AHEAD 172 173 /* The ilog2() calls fall out because they're constant */ 174 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \ 175 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name)) 176 177 /* 178 * The worker for the various blk_add_trace*() types. Fills out a 179 * blk_io_trace structure and places it in a per-cpu subbuffer. 180 */ 181 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 182 int rw, u32 what, int error, int pdu_len, void *pdu_data) 183 { 184 struct task_struct *tsk = current; 185 struct ring_buffer_event *event = NULL; 186 struct ring_buffer *buffer = NULL; 187 struct blk_io_trace *t; 188 unsigned long flags = 0; 189 unsigned long *sequence; 190 pid_t pid; 191 int cpu, pc = 0; 192 bool blk_tracer = blk_tracer_enabled; 193 194 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 195 return; 196 197 what |= ddir_act[rw & WRITE]; 198 what |= MASK_TC_BIT(rw, SYNC); 199 what |= MASK_TC_BIT(rw, RAHEAD); 200 what |= MASK_TC_BIT(rw, META); 201 what |= MASK_TC_BIT(rw, DISCARD); 202 203 pid = tsk->pid; 204 if (act_log_check(bt, what, sector, pid)) 205 return; 206 cpu = raw_smp_processor_id(); 207 208 if (blk_tracer) { 209 tracing_record_cmdline(current); 210 211 buffer = blk_tr->buffer; 212 pc = preempt_count(); 213 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 214 sizeof(*t) + pdu_len, 215 0, pc); 216 if (!event) 217 return; 218 t = ring_buffer_event_data(event); 219 goto record_it; 220 } 221 222 /* 223 * A word about the locking here - we disable interrupts to reserve 224 * some space in the relay per-cpu buffer, to prevent an irq 225 * from coming in and stepping on our toes. 226 */ 227 local_irq_save(flags); 228 229 if (unlikely(tsk->btrace_seq != blktrace_seq)) 230 trace_note_tsk(bt, tsk); 231 232 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 233 if (t) { 234 sequence = per_cpu_ptr(bt->sequence, cpu); 235 236 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 237 t->sequence = ++(*sequence); 238 t->time = ktime_to_ns(ktime_get()); 239 record_it: 240 /* 241 * These two are not needed in ftrace as they are in the 242 * generic trace_entry, filled by tracing_generic_entry_update, 243 * but for the trace_event->bin() synthesizer benefit we do it 244 * here too. 245 */ 246 t->cpu = cpu; 247 t->pid = pid; 248 249 t->sector = sector; 250 t->bytes = bytes; 251 t->action = what; 252 t->device = bt->dev; 253 t->error = error; 254 t->pdu_len = pdu_len; 255 256 if (pdu_len) 257 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 258 259 if (blk_tracer) { 260 trace_buffer_unlock_commit(buffer, event, 0, pc); 261 return; 262 } 263 } 264 265 local_irq_restore(flags); 266 } 267 268 static struct dentry *blk_tree_root; 269 static DEFINE_MUTEX(blk_tree_mutex); 270 271 static void blk_trace_free(struct blk_trace *bt) 272 { 273 debugfs_remove(bt->msg_file); 274 debugfs_remove(bt->dropped_file); 275 relay_close(bt->rchan); 276 debugfs_remove(bt->dir); 277 free_percpu(bt->sequence); 278 free_percpu(bt->msg_data); 279 kfree(bt); 280 } 281 282 static void blk_trace_cleanup(struct blk_trace *bt) 283 { 284 blk_trace_free(bt); 285 if (atomic_dec_and_test(&blk_probes_ref)) 286 blk_unregister_tracepoints(); 287 } 288 289 int blk_trace_remove(struct request_queue *q) 290 { 291 struct blk_trace *bt; 292 293 bt = xchg(&q->blk_trace, NULL); 294 if (!bt) 295 return -EINVAL; 296 297 if (bt->trace_state != Blktrace_running) 298 blk_trace_cleanup(bt); 299 300 return 0; 301 } 302 EXPORT_SYMBOL_GPL(blk_trace_remove); 303 304 static int blk_dropped_open(struct inode *inode, struct file *filp) 305 { 306 filp->private_data = inode->i_private; 307 308 return 0; 309 } 310 311 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 312 size_t count, loff_t *ppos) 313 { 314 struct blk_trace *bt = filp->private_data; 315 char buf[16]; 316 317 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 318 319 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 320 } 321 322 static const struct file_operations blk_dropped_fops = { 323 .owner = THIS_MODULE, 324 .open = blk_dropped_open, 325 .read = blk_dropped_read, 326 .llseek = default_llseek, 327 }; 328 329 static int blk_msg_open(struct inode *inode, struct file *filp) 330 { 331 filp->private_data = inode->i_private; 332 333 return 0; 334 } 335 336 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 337 size_t count, loff_t *ppos) 338 { 339 char *msg; 340 struct blk_trace *bt; 341 342 if (count >= BLK_TN_MAX_MSG) 343 return -EINVAL; 344 345 msg = kmalloc(count + 1, GFP_KERNEL); 346 if (msg == NULL) 347 return -ENOMEM; 348 349 if (copy_from_user(msg, buffer, count)) { 350 kfree(msg); 351 return -EFAULT; 352 } 353 354 msg[count] = '\0'; 355 bt = filp->private_data; 356 __trace_note_message(bt, "%s", msg); 357 kfree(msg); 358 359 return count; 360 } 361 362 static const struct file_operations blk_msg_fops = { 363 .owner = THIS_MODULE, 364 .open = blk_msg_open, 365 .write = blk_msg_write, 366 .llseek = noop_llseek, 367 }; 368 369 /* 370 * Keep track of how many times we encountered a full subbuffer, to aid 371 * the user space app in telling how many lost events there were. 372 */ 373 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 374 void *prev_subbuf, size_t prev_padding) 375 { 376 struct blk_trace *bt; 377 378 if (!relay_buf_full(buf)) 379 return 1; 380 381 bt = buf->chan->private_data; 382 atomic_inc(&bt->dropped); 383 return 0; 384 } 385 386 static int blk_remove_buf_file_callback(struct dentry *dentry) 387 { 388 debugfs_remove(dentry); 389 390 return 0; 391 } 392 393 static struct dentry *blk_create_buf_file_callback(const char *filename, 394 struct dentry *parent, 395 int mode, 396 struct rchan_buf *buf, 397 int *is_global) 398 { 399 return debugfs_create_file(filename, mode, parent, buf, 400 &relay_file_operations); 401 } 402 403 static struct rchan_callbacks blk_relay_callbacks = { 404 .subbuf_start = blk_subbuf_start_callback, 405 .create_buf_file = blk_create_buf_file_callback, 406 .remove_buf_file = blk_remove_buf_file_callback, 407 }; 408 409 static void blk_trace_setup_lba(struct blk_trace *bt, 410 struct block_device *bdev) 411 { 412 struct hd_struct *part = NULL; 413 414 if (bdev) 415 part = bdev->bd_part; 416 417 if (part) { 418 bt->start_lba = part->start_sect; 419 bt->end_lba = part->start_sect + part->nr_sects; 420 } else { 421 bt->start_lba = 0; 422 bt->end_lba = -1ULL; 423 } 424 } 425 426 /* 427 * Setup everything required to start tracing 428 */ 429 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 430 struct block_device *bdev, 431 struct blk_user_trace_setup *buts) 432 { 433 struct blk_trace *old_bt, *bt = NULL; 434 struct dentry *dir = NULL; 435 int ret, i; 436 437 if (!buts->buf_size || !buts->buf_nr) 438 return -EINVAL; 439 440 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 441 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 442 443 /* 444 * some device names have larger paths - convert the slashes 445 * to underscores for this to work as expected 446 */ 447 for (i = 0; i < strlen(buts->name); i++) 448 if (buts->name[i] == '/') 449 buts->name[i] = '_'; 450 451 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 452 if (!bt) 453 return -ENOMEM; 454 455 ret = -ENOMEM; 456 bt->sequence = alloc_percpu(unsigned long); 457 if (!bt->sequence) 458 goto err; 459 460 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 461 if (!bt->msg_data) 462 goto err; 463 464 ret = -ENOENT; 465 466 mutex_lock(&blk_tree_mutex); 467 if (!blk_tree_root) { 468 blk_tree_root = debugfs_create_dir("block", NULL); 469 if (!blk_tree_root) { 470 mutex_unlock(&blk_tree_mutex); 471 goto err; 472 } 473 } 474 mutex_unlock(&blk_tree_mutex); 475 476 dir = debugfs_create_dir(buts->name, blk_tree_root); 477 478 if (!dir) 479 goto err; 480 481 bt->dir = dir; 482 bt->dev = dev; 483 atomic_set(&bt->dropped, 0); 484 485 ret = -EIO; 486 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 487 &blk_dropped_fops); 488 if (!bt->dropped_file) 489 goto err; 490 491 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 492 if (!bt->msg_file) 493 goto err; 494 495 bt->rchan = relay_open("trace", dir, buts->buf_size, 496 buts->buf_nr, &blk_relay_callbacks, bt); 497 if (!bt->rchan) 498 goto err; 499 500 bt->act_mask = buts->act_mask; 501 if (!bt->act_mask) 502 bt->act_mask = (u16) -1; 503 504 blk_trace_setup_lba(bt, bdev); 505 506 /* overwrite with user settings */ 507 if (buts->start_lba) 508 bt->start_lba = buts->start_lba; 509 if (buts->end_lba) 510 bt->end_lba = buts->end_lba; 511 512 bt->pid = buts->pid; 513 bt->trace_state = Blktrace_setup; 514 515 ret = -EBUSY; 516 old_bt = xchg(&q->blk_trace, bt); 517 if (old_bt) { 518 (void) xchg(&q->blk_trace, old_bt); 519 goto err; 520 } 521 522 if (atomic_inc_return(&blk_probes_ref) == 1) 523 blk_register_tracepoints(); 524 525 return 0; 526 err: 527 blk_trace_free(bt); 528 return ret; 529 } 530 531 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 532 struct block_device *bdev, 533 char __user *arg) 534 { 535 struct blk_user_trace_setup buts; 536 int ret; 537 538 ret = copy_from_user(&buts, arg, sizeof(buts)); 539 if (ret) 540 return -EFAULT; 541 542 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 543 if (ret) 544 return ret; 545 546 if (copy_to_user(arg, &buts, sizeof(buts))) { 547 blk_trace_remove(q); 548 return -EFAULT; 549 } 550 return 0; 551 } 552 EXPORT_SYMBOL_GPL(blk_trace_setup); 553 554 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 555 static int compat_blk_trace_setup(struct request_queue *q, char *name, 556 dev_t dev, struct block_device *bdev, 557 char __user *arg) 558 { 559 struct blk_user_trace_setup buts; 560 struct compat_blk_user_trace_setup cbuts; 561 int ret; 562 563 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 564 return -EFAULT; 565 566 buts = (struct blk_user_trace_setup) { 567 .act_mask = cbuts.act_mask, 568 .buf_size = cbuts.buf_size, 569 .buf_nr = cbuts.buf_nr, 570 .start_lba = cbuts.start_lba, 571 .end_lba = cbuts.end_lba, 572 .pid = cbuts.pid, 573 }; 574 memcpy(&buts.name, &cbuts.name, 32); 575 576 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 577 if (ret) 578 return ret; 579 580 if (copy_to_user(arg, &buts.name, 32)) { 581 blk_trace_remove(q); 582 return -EFAULT; 583 } 584 585 return 0; 586 } 587 #endif 588 589 int blk_trace_startstop(struct request_queue *q, int start) 590 { 591 int ret; 592 struct blk_trace *bt = q->blk_trace; 593 594 if (bt == NULL) 595 return -EINVAL; 596 597 /* 598 * For starting a trace, we can transition from a setup or stopped 599 * trace. For stopping a trace, the state must be running 600 */ 601 ret = -EINVAL; 602 if (start) { 603 if (bt->trace_state == Blktrace_setup || 604 bt->trace_state == Blktrace_stopped) { 605 blktrace_seq++; 606 smp_mb(); 607 bt->trace_state = Blktrace_running; 608 609 trace_note_time(bt); 610 ret = 0; 611 } 612 } else { 613 if (bt->trace_state == Blktrace_running) { 614 bt->trace_state = Blktrace_stopped; 615 relay_flush(bt->rchan); 616 ret = 0; 617 } 618 } 619 620 return ret; 621 } 622 EXPORT_SYMBOL_GPL(blk_trace_startstop); 623 624 /** 625 * blk_trace_ioctl: - handle the ioctls associated with tracing 626 * @bdev: the block device 627 * @cmd: the ioctl cmd 628 * @arg: the argument data, if any 629 * 630 **/ 631 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 632 { 633 struct request_queue *q; 634 int ret, start = 0; 635 char b[BDEVNAME_SIZE]; 636 637 q = bdev_get_queue(bdev); 638 if (!q) 639 return -ENXIO; 640 641 mutex_lock(&bdev->bd_mutex); 642 643 switch (cmd) { 644 case BLKTRACESETUP: 645 bdevname(bdev, b); 646 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 647 break; 648 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 649 case BLKTRACESETUP32: 650 bdevname(bdev, b); 651 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 652 break; 653 #endif 654 case BLKTRACESTART: 655 start = 1; 656 case BLKTRACESTOP: 657 ret = blk_trace_startstop(q, start); 658 break; 659 case BLKTRACETEARDOWN: 660 ret = blk_trace_remove(q); 661 break; 662 default: 663 ret = -ENOTTY; 664 break; 665 } 666 667 mutex_unlock(&bdev->bd_mutex); 668 return ret; 669 } 670 671 /** 672 * blk_trace_shutdown: - stop and cleanup trace structures 673 * @q: the request queue associated with the device 674 * 675 **/ 676 void blk_trace_shutdown(struct request_queue *q) 677 { 678 if (q->blk_trace) { 679 blk_trace_startstop(q, 0); 680 blk_trace_remove(q); 681 } 682 } 683 684 /* 685 * blktrace probes 686 */ 687 688 /** 689 * blk_add_trace_rq - Add a trace for a request oriented action 690 * @q: queue the io is for 691 * @rq: the source request 692 * @what: the action 693 * 694 * Description: 695 * Records an action against a request. Will log the bio offset + size. 696 * 697 **/ 698 static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 699 u32 what) 700 { 701 struct blk_trace *bt = q->blk_trace; 702 int rw = rq->cmd_flags & 0x03; 703 704 if (likely(!bt)) 705 return; 706 707 if (rq->cmd_flags & REQ_DISCARD) 708 rw |= REQ_DISCARD; 709 710 if (rq->cmd_flags & REQ_SECURE) 711 rw |= REQ_SECURE; 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 * @error: error, if any 762 * 763 * Description: 764 * Records an action against a bio. Will log the bio offset + size. 765 * 766 **/ 767 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 768 u32 what, int error) 769 { 770 struct blk_trace *bt = q->blk_trace; 771 772 if (likely(!bt)) 773 return; 774 775 if (!error && !bio_flagged(bio, BIO_UPTODATE)) 776 error = EIO; 777 778 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, 779 error, 0, NULL); 780 } 781 782 static void blk_add_trace_bio_bounce(void *ignore, 783 struct request_queue *q, struct bio *bio) 784 { 785 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0); 786 } 787 788 static void blk_add_trace_bio_complete(void *ignore, 789 struct request_queue *q, struct bio *bio, 790 int error) 791 { 792 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error); 793 } 794 795 static void blk_add_trace_bio_backmerge(void *ignore, 796 struct request_queue *q, 797 struct bio *bio) 798 { 799 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0); 800 } 801 802 static void blk_add_trace_bio_frontmerge(void *ignore, 803 struct request_queue *q, 804 struct bio *bio) 805 { 806 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0); 807 } 808 809 static void blk_add_trace_bio_queue(void *ignore, 810 struct request_queue *q, struct bio *bio) 811 { 812 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0); 813 } 814 815 static void blk_add_trace_getrq(void *ignore, 816 struct request_queue *q, 817 struct bio *bio, int rw) 818 { 819 if (bio) 820 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0); 821 else { 822 struct blk_trace *bt = q->blk_trace; 823 824 if (bt) 825 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); 826 } 827 } 828 829 830 static void blk_add_trace_sleeprq(void *ignore, 831 struct request_queue *q, 832 struct bio *bio, int rw) 833 { 834 if (bio) 835 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0); 836 else { 837 struct blk_trace *bt = q->blk_trace; 838 839 if (bt) 840 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 841 0, 0, NULL); 842 } 843 } 844 845 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 846 { 847 struct blk_trace *bt = q->blk_trace; 848 849 if (bt) 850 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 851 } 852 853 static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q) 854 { 855 struct blk_trace *bt = q->blk_trace; 856 857 if (bt) { 858 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 859 __be64 rpdu = cpu_to_be64(pdu); 860 861 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0, 862 sizeof(rpdu), &rpdu); 863 } 864 } 865 866 static void blk_add_trace_unplug_timer(void *ignore, struct request_queue *q) 867 { 868 struct blk_trace *bt = q->blk_trace; 869 870 if (bt) { 871 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 872 __be64 rpdu = cpu_to_be64(pdu); 873 874 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0, 875 sizeof(rpdu), &rpdu); 876 } 877 } 878 879 static void blk_add_trace_split(void *ignore, 880 struct request_queue *q, struct bio *bio, 881 unsigned int pdu) 882 { 883 struct blk_trace *bt = q->blk_trace; 884 885 if (bt) { 886 __be64 rpdu = cpu_to_be64(pdu); 887 888 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 889 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE), 890 sizeof(rpdu), &rpdu); 891 } 892 } 893 894 /** 895 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation 896 * @ignore: trace callback data parameter (not used) 897 * @q: queue the io is for 898 * @bio: the source bio 899 * @dev: target device 900 * @from: source sector 901 * 902 * Description: 903 * Device mapper or raid target sometimes need to split a bio because 904 * it spans a stripe (or similar). Add a trace for that action. 905 * 906 **/ 907 static void blk_add_trace_bio_remap(void *ignore, 908 struct request_queue *q, struct bio *bio, 909 dev_t dev, sector_t from) 910 { 911 struct blk_trace *bt = q->blk_trace; 912 struct blk_io_trace_remap r; 913 914 if (likely(!bt)) 915 return; 916 917 r.device_from = cpu_to_be32(dev); 918 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 919 r.sector_from = cpu_to_be64(from); 920 921 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 922 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), 923 sizeof(r), &r); 924 } 925 926 /** 927 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 928 * @ignore: trace callback data parameter (not used) 929 * @q: queue the io is for 930 * @rq: the source request 931 * @dev: target device 932 * @from: source sector 933 * 934 * Description: 935 * Device mapper remaps request to other devices. 936 * Add a trace for that action. 937 * 938 **/ 939 static void blk_add_trace_rq_remap(void *ignore, 940 struct request_queue *q, 941 struct request *rq, dev_t dev, 942 sector_t from) 943 { 944 struct blk_trace *bt = q->blk_trace; 945 struct blk_io_trace_remap r; 946 947 if (likely(!bt)) 948 return; 949 950 r.device_from = cpu_to_be32(dev); 951 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 952 r.sector_from = cpu_to_be64(from); 953 954 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 955 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors, 956 sizeof(r), &r); 957 } 958 959 /** 960 * blk_add_driver_data - Add binary message with driver-specific data 961 * @q: queue the io is for 962 * @rq: io request 963 * @data: driver-specific data 964 * @len: length of driver-specific data 965 * 966 * Description: 967 * Some drivers might want to write driver-specific data per request. 968 * 969 **/ 970 void blk_add_driver_data(struct request_queue *q, 971 struct request *rq, 972 void *data, size_t len) 973 { 974 struct blk_trace *bt = q->blk_trace; 975 976 if (likely(!bt)) 977 return; 978 979 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) 980 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 981 BLK_TA_DRV_DATA, rq->errors, len, data); 982 else 983 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 984 BLK_TA_DRV_DATA, rq->errors, len, data); 985 } 986 EXPORT_SYMBOL_GPL(blk_add_driver_data); 987 988 static void blk_register_tracepoints(void) 989 { 990 int ret; 991 992 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 993 WARN_ON(ret); 994 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 995 WARN_ON(ret); 996 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 997 WARN_ON(ret); 998 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 999 WARN_ON(ret); 1000 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1001 WARN_ON(ret); 1002 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1003 WARN_ON(ret); 1004 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1005 WARN_ON(ret); 1006 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1007 WARN_ON(ret); 1008 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1009 WARN_ON(ret); 1010 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1011 WARN_ON(ret); 1012 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 1013 WARN_ON(ret); 1014 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1015 WARN_ON(ret); 1016 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 1017 WARN_ON(ret); 1018 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL); 1019 WARN_ON(ret); 1020 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); 1021 WARN_ON(ret); 1022 ret = register_trace_block_split(blk_add_trace_split, NULL); 1023 WARN_ON(ret); 1024 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1025 WARN_ON(ret); 1026 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1027 WARN_ON(ret); 1028 } 1029 1030 static void blk_unregister_tracepoints(void) 1031 { 1032 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1033 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1034 unregister_trace_block_split(blk_add_trace_split, NULL); 1035 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); 1036 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL); 1037 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1038 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1039 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1040 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1041 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1042 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1043 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1044 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1045 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1046 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1047 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1048 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1049 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 1050 1051 tracepoint_synchronize_unregister(); 1052 } 1053 1054 /* 1055 * struct blk_io_tracer formatting routines 1056 */ 1057 1058 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1059 { 1060 int i = 0; 1061 int tc = t->action >> BLK_TC_SHIFT; 1062 1063 if (t->action == BLK_TN_MESSAGE) { 1064 rwbs[i++] = 'N'; 1065 goto out; 1066 } 1067 1068 if (tc & BLK_TC_DISCARD) 1069 rwbs[i++] = 'D'; 1070 else if (tc & BLK_TC_WRITE) 1071 rwbs[i++] = 'W'; 1072 else if (t->bytes) 1073 rwbs[i++] = 'R'; 1074 else 1075 rwbs[i++] = 'N'; 1076 1077 if (tc & BLK_TC_AHEAD) 1078 rwbs[i++] = 'A'; 1079 if (tc & BLK_TC_BARRIER) 1080 rwbs[i++] = 'B'; 1081 if (tc & BLK_TC_SYNC) 1082 rwbs[i++] = 'S'; 1083 if (tc & BLK_TC_META) 1084 rwbs[i++] = 'M'; 1085 out: 1086 rwbs[i] = '\0'; 1087 } 1088 1089 static inline 1090 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1091 { 1092 return (const struct blk_io_trace *)ent; 1093 } 1094 1095 static inline const void *pdu_start(const struct trace_entry *ent) 1096 { 1097 return te_blk_io_trace(ent) + 1; 1098 } 1099 1100 static inline u32 t_action(const struct trace_entry *ent) 1101 { 1102 return te_blk_io_trace(ent)->action; 1103 } 1104 1105 static inline u32 t_bytes(const struct trace_entry *ent) 1106 { 1107 return te_blk_io_trace(ent)->bytes; 1108 } 1109 1110 static inline u32 t_sec(const struct trace_entry *ent) 1111 { 1112 return te_blk_io_trace(ent)->bytes >> 9; 1113 } 1114 1115 static inline unsigned long long t_sector(const struct trace_entry *ent) 1116 { 1117 return te_blk_io_trace(ent)->sector; 1118 } 1119 1120 static inline __u16 t_error(const struct trace_entry *ent) 1121 { 1122 return te_blk_io_trace(ent)->error; 1123 } 1124 1125 static __u64 get_pdu_int(const struct trace_entry *ent) 1126 { 1127 const __u64 *val = pdu_start(ent); 1128 return be64_to_cpu(*val); 1129 } 1130 1131 static void get_pdu_remap(const struct trace_entry *ent, 1132 struct blk_io_trace_remap *r) 1133 { 1134 const struct blk_io_trace_remap *__r = pdu_start(ent); 1135 __u64 sector_from = __r->sector_from; 1136 1137 r->device_from = be32_to_cpu(__r->device_from); 1138 r->device_to = be32_to_cpu(__r->device_to); 1139 r->sector_from = be64_to_cpu(sector_from); 1140 } 1141 1142 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1143 1144 static int blk_log_action_classic(struct trace_iterator *iter, const char *act) 1145 { 1146 char rwbs[6]; 1147 unsigned long long ts = iter->ts; 1148 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1149 unsigned secs = (unsigned long)ts; 1150 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1151 1152 fill_rwbs(rwbs, t); 1153 1154 return trace_seq_printf(&iter->seq, 1155 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1156 MAJOR(t->device), MINOR(t->device), iter->cpu, 1157 secs, nsec_rem, iter->ent->pid, act, rwbs); 1158 } 1159 1160 static int blk_log_action(struct trace_iterator *iter, const char *act) 1161 { 1162 char rwbs[6]; 1163 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1164 1165 fill_rwbs(rwbs, t); 1166 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1167 MAJOR(t->device), MINOR(t->device), act, rwbs); 1168 } 1169 1170 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1171 { 1172 const unsigned char *pdu_buf; 1173 int pdu_len; 1174 int i, end, ret; 1175 1176 pdu_buf = pdu_start(ent); 1177 pdu_len = te_blk_io_trace(ent)->pdu_len; 1178 1179 if (!pdu_len) 1180 return 1; 1181 1182 /* find the last zero that needs to be printed */ 1183 for (end = pdu_len - 1; end >= 0; end--) 1184 if (pdu_buf[end]) 1185 break; 1186 end++; 1187 1188 if (!trace_seq_putc(s, '(')) 1189 return 0; 1190 1191 for (i = 0; i < pdu_len; i++) { 1192 1193 ret = trace_seq_printf(s, "%s%02x", 1194 i == 0 ? "" : " ", pdu_buf[i]); 1195 if (!ret) 1196 return ret; 1197 1198 /* 1199 * stop when the rest is just zeroes and indicate so 1200 * with a ".." appended 1201 */ 1202 if (i == end && end != pdu_len - 1) 1203 return trace_seq_puts(s, " ..) "); 1204 } 1205 1206 return trace_seq_puts(s, ") "); 1207 } 1208 1209 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1210 { 1211 char cmd[TASK_COMM_LEN]; 1212 1213 trace_find_cmdline(ent->pid, cmd); 1214 1215 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1216 int ret; 1217 1218 ret = trace_seq_printf(s, "%u ", t_bytes(ent)); 1219 if (!ret) 1220 return 0; 1221 ret = blk_log_dump_pdu(s, ent); 1222 if (!ret) 1223 return 0; 1224 return trace_seq_printf(s, "[%s]\n", cmd); 1225 } else { 1226 if (t_sec(ent)) 1227 return trace_seq_printf(s, "%llu + %u [%s]\n", 1228 t_sector(ent), t_sec(ent), cmd); 1229 return trace_seq_printf(s, "[%s]\n", cmd); 1230 } 1231 } 1232 1233 static int blk_log_with_error(struct trace_seq *s, 1234 const struct trace_entry *ent) 1235 { 1236 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1237 int ret; 1238 1239 ret = blk_log_dump_pdu(s, ent); 1240 if (ret) 1241 return trace_seq_printf(s, "[%d]\n", t_error(ent)); 1242 return 0; 1243 } else { 1244 if (t_sec(ent)) 1245 return trace_seq_printf(s, "%llu + %u [%d]\n", 1246 t_sector(ent), 1247 t_sec(ent), t_error(ent)); 1248 return trace_seq_printf(s, "%llu [%d]\n", 1249 t_sector(ent), t_error(ent)); 1250 } 1251 } 1252 1253 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1254 { 1255 struct blk_io_trace_remap r = { .device_from = 0, }; 1256 1257 get_pdu_remap(ent, &r); 1258 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1259 t_sector(ent), t_sec(ent), 1260 MAJOR(r.device_from), MINOR(r.device_from), 1261 (unsigned long long)r.sector_from); 1262 } 1263 1264 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1265 { 1266 char cmd[TASK_COMM_LEN]; 1267 1268 trace_find_cmdline(ent->pid, cmd); 1269 1270 return trace_seq_printf(s, "[%s]\n", cmd); 1271 } 1272 1273 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1274 { 1275 char cmd[TASK_COMM_LEN]; 1276 1277 trace_find_cmdline(ent->pid, cmd); 1278 1279 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1280 } 1281 1282 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1283 { 1284 char cmd[TASK_COMM_LEN]; 1285 1286 trace_find_cmdline(ent->pid, cmd); 1287 1288 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1289 get_pdu_int(ent), cmd); 1290 } 1291 1292 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1293 { 1294 int ret; 1295 const struct blk_io_trace *t = te_blk_io_trace(ent); 1296 1297 ret = trace_seq_putmem(s, t + 1, t->pdu_len); 1298 if (ret) 1299 return trace_seq_putc(s, '\n'); 1300 return ret; 1301 } 1302 1303 /* 1304 * struct tracer operations 1305 */ 1306 1307 static void blk_tracer_print_header(struct seq_file *m) 1308 { 1309 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1310 return; 1311 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1312 "# | | | | | |\n"); 1313 } 1314 1315 static void blk_tracer_start(struct trace_array *tr) 1316 { 1317 blk_tracer_enabled = true; 1318 } 1319 1320 static int blk_tracer_init(struct trace_array *tr) 1321 { 1322 blk_tr = tr; 1323 blk_tracer_start(tr); 1324 return 0; 1325 } 1326 1327 static void blk_tracer_stop(struct trace_array *tr) 1328 { 1329 blk_tracer_enabled = false; 1330 } 1331 1332 static void blk_tracer_reset(struct trace_array *tr) 1333 { 1334 blk_tracer_stop(tr); 1335 } 1336 1337 static const struct { 1338 const char *act[2]; 1339 int (*print)(struct trace_seq *s, const struct trace_entry *ent); 1340 } what2act[] = { 1341 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1342 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1343 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1344 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1345 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1346 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1347 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1348 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1349 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1350 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1351 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1352 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1353 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1354 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1355 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1356 }; 1357 1358 static enum print_line_t print_one_line(struct trace_iterator *iter, 1359 bool classic) 1360 { 1361 struct trace_seq *s = &iter->seq; 1362 const struct blk_io_trace *t; 1363 u16 what; 1364 int ret; 1365 bool long_act; 1366 blk_log_action_t *log_action; 1367 1368 t = te_blk_io_trace(iter->ent); 1369 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1370 long_act = !!(trace_flags & TRACE_ITER_VERBOSE); 1371 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1372 1373 if (t->action == BLK_TN_MESSAGE) { 1374 ret = log_action(iter, long_act ? "message" : "m"); 1375 if (ret) 1376 ret = blk_log_msg(s, iter->ent); 1377 goto out; 1378 } 1379 1380 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1381 ret = trace_seq_printf(s, "Unknown action %x\n", what); 1382 else { 1383 ret = log_action(iter, what2act[what].act[long_act]); 1384 if (ret) 1385 ret = what2act[what].print(s, iter->ent); 1386 } 1387 out: 1388 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1389 } 1390 1391 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1392 int flags, struct trace_event *event) 1393 { 1394 return print_one_line(iter, false); 1395 } 1396 1397 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1398 { 1399 struct trace_seq *s = &iter->seq; 1400 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1401 const int offset = offsetof(struct blk_io_trace, sector); 1402 struct blk_io_trace old = { 1403 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1404 .time = iter->ts, 1405 }; 1406 1407 if (!trace_seq_putmem(s, &old, offset)) 1408 return 0; 1409 return trace_seq_putmem(s, &t->sector, 1410 sizeof(old) - offset + t->pdu_len); 1411 } 1412 1413 static enum print_line_t 1414 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1415 struct trace_event *event) 1416 { 1417 return blk_trace_synthesize_old_trace(iter) ? 1418 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1419 } 1420 1421 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1422 { 1423 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1424 return TRACE_TYPE_UNHANDLED; 1425 1426 return print_one_line(iter, true); 1427 } 1428 1429 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set) 1430 { 1431 /* don't output context-info for blk_classic output */ 1432 if (bit == TRACE_BLK_OPT_CLASSIC) { 1433 if (set) 1434 trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1435 else 1436 trace_flags |= TRACE_ITER_CONTEXT_INFO; 1437 } 1438 return 0; 1439 } 1440 1441 static struct tracer blk_tracer __read_mostly = { 1442 .name = "blk", 1443 .init = blk_tracer_init, 1444 .reset = blk_tracer_reset, 1445 .start = blk_tracer_start, 1446 .stop = blk_tracer_stop, 1447 .print_header = blk_tracer_print_header, 1448 .print_line = blk_tracer_print_line, 1449 .flags = &blk_tracer_flags, 1450 .set_flag = blk_tracer_set_flag, 1451 }; 1452 1453 static struct trace_event_functions trace_blk_event_funcs = { 1454 .trace = blk_trace_event_print, 1455 .binary = blk_trace_event_print_binary, 1456 }; 1457 1458 static struct trace_event trace_blk_event = { 1459 .type = TRACE_BLK, 1460 .funcs = &trace_blk_event_funcs, 1461 }; 1462 1463 static int __init init_blk_tracer(void) 1464 { 1465 if (!register_ftrace_event(&trace_blk_event)) { 1466 pr_warning("Warning: could not register block events\n"); 1467 return 1; 1468 } 1469 1470 if (register_tracer(&blk_tracer) != 0) { 1471 pr_warning("Warning: could not register the block tracer\n"); 1472 unregister_ftrace_event(&trace_blk_event); 1473 return 1; 1474 } 1475 1476 return 0; 1477 } 1478 1479 device_initcall(init_blk_tracer); 1480 1481 static int blk_trace_remove_queue(struct request_queue *q) 1482 { 1483 struct blk_trace *bt; 1484 1485 bt = xchg(&q->blk_trace, NULL); 1486 if (bt == NULL) 1487 return -EINVAL; 1488 1489 if (atomic_dec_and_test(&blk_probes_ref)) 1490 blk_unregister_tracepoints(); 1491 1492 blk_trace_free(bt); 1493 return 0; 1494 } 1495 1496 /* 1497 * Setup everything required to start tracing 1498 */ 1499 static int blk_trace_setup_queue(struct request_queue *q, 1500 struct block_device *bdev) 1501 { 1502 struct blk_trace *old_bt, *bt = NULL; 1503 int ret = -ENOMEM; 1504 1505 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1506 if (!bt) 1507 return -ENOMEM; 1508 1509 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1510 if (!bt->msg_data) 1511 goto free_bt; 1512 1513 bt->dev = bdev->bd_dev; 1514 bt->act_mask = (u16)-1; 1515 1516 blk_trace_setup_lba(bt, bdev); 1517 1518 old_bt = xchg(&q->blk_trace, bt); 1519 if (old_bt != NULL) { 1520 (void)xchg(&q->blk_trace, old_bt); 1521 ret = -EBUSY; 1522 goto free_bt; 1523 } 1524 1525 if (atomic_inc_return(&blk_probes_ref) == 1) 1526 blk_register_tracepoints(); 1527 return 0; 1528 1529 free_bt: 1530 blk_trace_free(bt); 1531 return ret; 1532 } 1533 1534 /* 1535 * sysfs interface to enable and configure tracing 1536 */ 1537 1538 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1539 struct device_attribute *attr, 1540 char *buf); 1541 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1542 struct device_attribute *attr, 1543 const char *buf, size_t count); 1544 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1545 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1546 sysfs_blk_trace_attr_show, \ 1547 sysfs_blk_trace_attr_store) 1548 1549 static BLK_TRACE_DEVICE_ATTR(enable); 1550 static BLK_TRACE_DEVICE_ATTR(act_mask); 1551 static BLK_TRACE_DEVICE_ATTR(pid); 1552 static BLK_TRACE_DEVICE_ATTR(start_lba); 1553 static BLK_TRACE_DEVICE_ATTR(end_lba); 1554 1555 static struct attribute *blk_trace_attrs[] = { 1556 &dev_attr_enable.attr, 1557 &dev_attr_act_mask.attr, 1558 &dev_attr_pid.attr, 1559 &dev_attr_start_lba.attr, 1560 &dev_attr_end_lba.attr, 1561 NULL 1562 }; 1563 1564 struct attribute_group blk_trace_attr_group = { 1565 .name = "trace", 1566 .attrs = blk_trace_attrs, 1567 }; 1568 1569 static const struct { 1570 int mask; 1571 const char *str; 1572 } mask_maps[] = { 1573 { BLK_TC_READ, "read" }, 1574 { BLK_TC_WRITE, "write" }, 1575 { BLK_TC_BARRIER, "barrier" }, 1576 { BLK_TC_SYNC, "sync" }, 1577 { BLK_TC_QUEUE, "queue" }, 1578 { BLK_TC_REQUEUE, "requeue" }, 1579 { BLK_TC_ISSUE, "issue" }, 1580 { BLK_TC_COMPLETE, "complete" }, 1581 { BLK_TC_FS, "fs" }, 1582 { BLK_TC_PC, "pc" }, 1583 { BLK_TC_AHEAD, "ahead" }, 1584 { BLK_TC_META, "meta" }, 1585 { BLK_TC_DISCARD, "discard" }, 1586 { BLK_TC_DRV_DATA, "drv_data" }, 1587 }; 1588 1589 static int blk_trace_str2mask(const char *str) 1590 { 1591 int i; 1592 int mask = 0; 1593 char *buf, *s, *token; 1594 1595 buf = kstrdup(str, GFP_KERNEL); 1596 if (buf == NULL) 1597 return -ENOMEM; 1598 s = strstrip(buf); 1599 1600 while (1) { 1601 token = strsep(&s, ","); 1602 if (token == NULL) 1603 break; 1604 1605 if (*token == '\0') 1606 continue; 1607 1608 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1609 if (strcasecmp(token, mask_maps[i].str) == 0) { 1610 mask |= mask_maps[i].mask; 1611 break; 1612 } 1613 } 1614 if (i == ARRAY_SIZE(mask_maps)) { 1615 mask = -EINVAL; 1616 break; 1617 } 1618 } 1619 kfree(buf); 1620 1621 return mask; 1622 } 1623 1624 static ssize_t blk_trace_mask2str(char *buf, int mask) 1625 { 1626 int i; 1627 char *p = buf; 1628 1629 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1630 if (mask & mask_maps[i].mask) { 1631 p += sprintf(p, "%s%s", 1632 (p == buf) ? "" : ",", mask_maps[i].str); 1633 } 1634 } 1635 *p++ = '\n'; 1636 1637 return p - buf; 1638 } 1639 1640 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1641 { 1642 if (bdev->bd_disk == NULL) 1643 return NULL; 1644 1645 return bdev_get_queue(bdev); 1646 } 1647 1648 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1649 struct device_attribute *attr, 1650 char *buf) 1651 { 1652 struct hd_struct *p = dev_to_part(dev); 1653 struct request_queue *q; 1654 struct block_device *bdev; 1655 ssize_t ret = -ENXIO; 1656 1657 bdev = bdget(part_devt(p)); 1658 if (bdev == NULL) 1659 goto out; 1660 1661 q = blk_trace_get_queue(bdev); 1662 if (q == NULL) 1663 goto out_bdput; 1664 1665 mutex_lock(&bdev->bd_mutex); 1666 1667 if (attr == &dev_attr_enable) { 1668 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1669 goto out_unlock_bdev; 1670 } 1671 1672 if (q->blk_trace == NULL) 1673 ret = sprintf(buf, "disabled\n"); 1674 else if (attr == &dev_attr_act_mask) 1675 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1676 else if (attr == &dev_attr_pid) 1677 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1678 else if (attr == &dev_attr_start_lba) 1679 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1680 else if (attr == &dev_attr_end_lba) 1681 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1682 1683 out_unlock_bdev: 1684 mutex_unlock(&bdev->bd_mutex); 1685 out_bdput: 1686 bdput(bdev); 1687 out: 1688 return ret; 1689 } 1690 1691 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1692 struct device_attribute *attr, 1693 const char *buf, size_t count) 1694 { 1695 struct block_device *bdev; 1696 struct request_queue *q; 1697 struct hd_struct *p; 1698 u64 value; 1699 ssize_t ret = -EINVAL; 1700 1701 if (count == 0) 1702 goto out; 1703 1704 if (attr == &dev_attr_act_mask) { 1705 if (sscanf(buf, "%llx", &value) != 1) { 1706 /* Assume it is a list of trace category names */ 1707 ret = blk_trace_str2mask(buf); 1708 if (ret < 0) 1709 goto out; 1710 value = ret; 1711 } 1712 } else if (sscanf(buf, "%llu", &value) != 1) 1713 goto out; 1714 1715 ret = -ENXIO; 1716 1717 p = dev_to_part(dev); 1718 bdev = bdget(part_devt(p)); 1719 if (bdev == NULL) 1720 goto out; 1721 1722 q = blk_trace_get_queue(bdev); 1723 if (q == NULL) 1724 goto out_bdput; 1725 1726 mutex_lock(&bdev->bd_mutex); 1727 1728 if (attr == &dev_attr_enable) { 1729 if (value) 1730 ret = blk_trace_setup_queue(q, bdev); 1731 else 1732 ret = blk_trace_remove_queue(q); 1733 goto out_unlock_bdev; 1734 } 1735 1736 ret = 0; 1737 if (q->blk_trace == NULL) 1738 ret = blk_trace_setup_queue(q, bdev); 1739 1740 if (ret == 0) { 1741 if (attr == &dev_attr_act_mask) 1742 q->blk_trace->act_mask = value; 1743 else if (attr == &dev_attr_pid) 1744 q->blk_trace->pid = value; 1745 else if (attr == &dev_attr_start_lba) 1746 q->blk_trace->start_lba = value; 1747 else if (attr == &dev_attr_end_lba) 1748 q->blk_trace->end_lba = value; 1749 } 1750 1751 out_unlock_bdev: 1752 mutex_unlock(&bdev->bd_mutex); 1753 out_bdput: 1754 bdput(bdev); 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_SYNC) 1814 rwbs[i++] = 'S'; 1815 if (rw & REQ_META) 1816 rwbs[i++] = 'M'; 1817 if (rw & REQ_SECURE) 1818 rwbs[i++] = 'E'; 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 if (rq->cmd_flags & REQ_SECURE) 1832 rw |= REQ_SECURE; 1833 1834 bytes = blk_rq_bytes(rq); 1835 1836 blk_fill_rwbs(rwbs, rw, bytes); 1837 } 1838 1839 #endif /* CONFIG_EVENT_TRACING */ 1840 1841