1 /* 2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 16 * 17 */ 18 #include <linux/kernel.h> 19 #include <linux/blkdev.h> 20 #include <linux/blktrace_api.h> 21 #include <linux/percpu.h> 22 #include <linux/init.h> 23 #include <linux/mutex.h> 24 #include <linux/slab.h> 25 #include <linux/debugfs.h> 26 #include <linux/export.h> 27 #include <linux/time.h> 28 #include <linux/uaccess.h> 29 #include <linux/list.h> 30 31 #include <trace/events/block.h> 32 33 #include "trace_output.h" 34 35 #ifdef CONFIG_BLK_DEV_IO_TRACE 36 37 static unsigned int blktrace_seq __read_mostly = 1; 38 39 static struct trace_array *blk_tr; 40 static bool blk_tracer_enabled __read_mostly; 41 42 static LIST_HEAD(running_trace_list); 43 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock); 44 45 /* Select an alternative, minimalistic output than the original one */ 46 #define TRACE_BLK_OPT_CLASSIC 0x1 47 48 static struct tracer_opt blk_tracer_opts[] = { 49 /* Default disable the minimalistic output */ 50 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 51 { } 52 }; 53 54 static struct tracer_flags blk_tracer_flags = { 55 .val = 0, 56 .opts = blk_tracer_opts, 57 }; 58 59 /* Global reference count of probes */ 60 static atomic_t blk_probes_ref = ATOMIC_INIT(0); 61 62 static void blk_register_tracepoints(void); 63 static void blk_unregister_tracepoints(void); 64 65 /* 66 * Send out a notify message. 67 */ 68 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 69 const void *data, size_t len) 70 { 71 struct blk_io_trace *t; 72 struct ring_buffer_event *event = NULL; 73 struct ring_buffer *buffer = NULL; 74 int pc = 0; 75 int cpu = smp_processor_id(); 76 bool blk_tracer = blk_tracer_enabled; 77 78 if (blk_tracer) { 79 buffer = blk_tr->trace_buffer.buffer; 80 pc = preempt_count(); 81 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 82 sizeof(*t) + len, 83 0, pc); 84 if (!event) 85 return; 86 t = ring_buffer_event_data(event); 87 goto record_it; 88 } 89 90 if (!bt->rchan) 91 return; 92 93 t = relay_reserve(bt->rchan, sizeof(*t) + len); 94 if (t) { 95 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 96 t->time = ktime_to_ns(ktime_get()); 97 record_it: 98 t->device = bt->dev; 99 t->action = action; 100 t->pid = pid; 101 t->cpu = cpu; 102 t->pdu_len = len; 103 memcpy((void *) t + sizeof(*t), data, len); 104 105 if (blk_tracer) 106 trace_buffer_unlock_commit(buffer, event, 0, pc); 107 } 108 } 109 110 /* 111 * Send out a notify for this process, if we haven't done so since a trace 112 * started 113 */ 114 static void trace_note_tsk(struct task_struct *tsk) 115 { 116 unsigned long flags; 117 struct blk_trace *bt; 118 119 tsk->btrace_seq = blktrace_seq; 120 spin_lock_irqsave(&running_trace_lock, flags); 121 list_for_each_entry(bt, &running_trace_list, running_list) { 122 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, 123 sizeof(tsk->comm)); 124 } 125 spin_unlock_irqrestore(&running_trace_lock, flags); 126 } 127 128 static void trace_note_time(struct blk_trace *bt) 129 { 130 struct timespec now; 131 unsigned long flags; 132 u32 words[2]; 133 134 getnstimeofday(&now); 135 words[0] = now.tv_sec; 136 words[1] = now.tv_nsec; 137 138 local_irq_save(flags); 139 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); 140 local_irq_restore(flags); 141 } 142 143 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 144 { 145 int n; 146 va_list args; 147 unsigned long flags; 148 char *buf; 149 150 if (unlikely(bt->trace_state != Blktrace_running && 151 !blk_tracer_enabled)) 152 return; 153 154 /* 155 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note 156 * message to the trace. 157 */ 158 if (!(bt->act_mask & BLK_TC_NOTIFY)) 159 return; 160 161 local_irq_save(flags); 162 buf = this_cpu_ptr(bt->msg_data); 163 va_start(args, fmt); 164 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 165 va_end(args); 166 167 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); 168 local_irq_restore(flags); 169 } 170 EXPORT_SYMBOL_GPL(__trace_note_message); 171 172 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 173 pid_t pid) 174 { 175 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 176 return 1; 177 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 178 return 1; 179 if (bt->pid && pid != bt->pid) 180 return 1; 181 182 return 0; 183 } 184 185 /* 186 * Data direction bit lookup 187 */ 188 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 189 BLK_TC_ACT(BLK_TC_WRITE) }; 190 191 #define BLK_TC_RAHEAD BLK_TC_AHEAD 192 193 /* The ilog2() calls fall out because they're constant */ 194 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \ 195 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name)) 196 197 /* 198 * The worker for the various blk_add_trace*() types. Fills out a 199 * blk_io_trace structure and places it in a per-cpu subbuffer. 200 */ 201 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 202 int rw, u32 what, int error, int pdu_len, void *pdu_data) 203 { 204 struct task_struct *tsk = current; 205 struct ring_buffer_event *event = NULL; 206 struct ring_buffer *buffer = NULL; 207 struct blk_io_trace *t; 208 unsigned long flags = 0; 209 unsigned long *sequence; 210 pid_t pid; 211 int cpu, pc = 0; 212 bool blk_tracer = blk_tracer_enabled; 213 214 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 215 return; 216 217 what |= ddir_act[rw & WRITE]; 218 what |= MASK_TC_BIT(rw, SYNC); 219 what |= MASK_TC_BIT(rw, RAHEAD); 220 what |= MASK_TC_BIT(rw, META); 221 what |= MASK_TC_BIT(rw, DISCARD); 222 what |= MASK_TC_BIT(rw, FLUSH); 223 what |= MASK_TC_BIT(rw, FUA); 224 225 pid = tsk->pid; 226 if (act_log_check(bt, what, sector, pid)) 227 return; 228 cpu = raw_smp_processor_id(); 229 230 if (blk_tracer) { 231 tracing_record_cmdline(current); 232 233 buffer = blk_tr->trace_buffer.buffer; 234 pc = preempt_count(); 235 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 236 sizeof(*t) + pdu_len, 237 0, pc); 238 if (!event) 239 return; 240 t = ring_buffer_event_data(event); 241 goto record_it; 242 } 243 244 if (unlikely(tsk->btrace_seq != blktrace_seq)) 245 trace_note_tsk(tsk); 246 247 /* 248 * A word about the locking here - we disable interrupts to reserve 249 * some space in the relay per-cpu buffer, to prevent an irq 250 * from coming in and stepping on our toes. 251 */ 252 local_irq_save(flags); 253 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 254 if (t) { 255 sequence = per_cpu_ptr(bt->sequence, cpu); 256 257 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 258 t->sequence = ++(*sequence); 259 t->time = ktime_to_ns(ktime_get()); 260 record_it: 261 /* 262 * These two are not needed in ftrace as they are in the 263 * generic trace_entry, filled by tracing_generic_entry_update, 264 * but for the trace_event->bin() synthesizer benefit we do it 265 * here too. 266 */ 267 t->cpu = cpu; 268 t->pid = pid; 269 270 t->sector = sector; 271 t->bytes = bytes; 272 t->action = what; 273 t->device = bt->dev; 274 t->error = error; 275 t->pdu_len = pdu_len; 276 277 if (pdu_len) 278 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 279 280 if (blk_tracer) { 281 trace_buffer_unlock_commit(buffer, event, 0, pc); 282 return; 283 } 284 } 285 286 local_irq_restore(flags); 287 } 288 289 static struct dentry *blk_tree_root; 290 static DEFINE_MUTEX(blk_tree_mutex); 291 292 static void blk_trace_free(struct blk_trace *bt) 293 { 294 debugfs_remove(bt->msg_file); 295 debugfs_remove(bt->dropped_file); 296 relay_close(bt->rchan); 297 debugfs_remove(bt->dir); 298 free_percpu(bt->sequence); 299 free_percpu(bt->msg_data); 300 kfree(bt); 301 } 302 303 static void blk_trace_cleanup(struct blk_trace *bt) 304 { 305 blk_trace_free(bt); 306 if (atomic_dec_and_test(&blk_probes_ref)) 307 blk_unregister_tracepoints(); 308 } 309 310 int blk_trace_remove(struct request_queue *q) 311 { 312 struct blk_trace *bt; 313 314 bt = xchg(&q->blk_trace, NULL); 315 if (!bt) 316 return -EINVAL; 317 318 if (bt->trace_state != Blktrace_running) 319 blk_trace_cleanup(bt); 320 321 return 0; 322 } 323 EXPORT_SYMBOL_GPL(blk_trace_remove); 324 325 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 326 size_t count, loff_t *ppos) 327 { 328 struct blk_trace *bt = filp->private_data; 329 char buf[16]; 330 331 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 332 333 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 334 } 335 336 static const struct file_operations blk_dropped_fops = { 337 .owner = THIS_MODULE, 338 .open = simple_open, 339 .read = blk_dropped_read, 340 .llseek = default_llseek, 341 }; 342 343 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 344 size_t count, loff_t *ppos) 345 { 346 char *msg; 347 struct blk_trace *bt; 348 349 if (count >= BLK_TN_MAX_MSG) 350 return -EINVAL; 351 352 msg = kmalloc(count + 1, GFP_KERNEL); 353 if (msg == NULL) 354 return -ENOMEM; 355 356 if (copy_from_user(msg, buffer, count)) { 357 kfree(msg); 358 return -EFAULT; 359 } 360 361 msg[count] = '\0'; 362 bt = filp->private_data; 363 __trace_note_message(bt, "%s", msg); 364 kfree(msg); 365 366 return count; 367 } 368 369 static const struct file_operations blk_msg_fops = { 370 .owner = THIS_MODULE, 371 .open = simple_open, 372 .write = blk_msg_write, 373 .llseek = noop_llseek, 374 }; 375 376 /* 377 * Keep track of how many times we encountered a full subbuffer, to aid 378 * the user space app in telling how many lost events there were. 379 */ 380 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 381 void *prev_subbuf, size_t prev_padding) 382 { 383 struct blk_trace *bt; 384 385 if (!relay_buf_full(buf)) 386 return 1; 387 388 bt = buf->chan->private_data; 389 atomic_inc(&bt->dropped); 390 return 0; 391 } 392 393 static int blk_remove_buf_file_callback(struct dentry *dentry) 394 { 395 debugfs_remove(dentry); 396 397 return 0; 398 } 399 400 static struct dentry *blk_create_buf_file_callback(const char *filename, 401 struct dentry *parent, 402 umode_t mode, 403 struct rchan_buf *buf, 404 int *is_global) 405 { 406 return debugfs_create_file(filename, mode, parent, buf, 407 &relay_file_operations); 408 } 409 410 static struct rchan_callbacks blk_relay_callbacks = { 411 .subbuf_start = blk_subbuf_start_callback, 412 .create_buf_file = blk_create_buf_file_callback, 413 .remove_buf_file = blk_remove_buf_file_callback, 414 }; 415 416 static void blk_trace_setup_lba(struct blk_trace *bt, 417 struct block_device *bdev) 418 { 419 struct hd_struct *part = NULL; 420 421 if (bdev) 422 part = bdev->bd_part; 423 424 if (part) { 425 bt->start_lba = part->start_sect; 426 bt->end_lba = part->start_sect + part->nr_sects; 427 } else { 428 bt->start_lba = 0; 429 bt->end_lba = -1ULL; 430 } 431 } 432 433 /* 434 * Setup everything required to start tracing 435 */ 436 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 437 struct block_device *bdev, 438 struct blk_user_trace_setup *buts) 439 { 440 struct blk_trace *old_bt, *bt = NULL; 441 struct dentry *dir = NULL; 442 int ret, i; 443 444 if (!buts->buf_size || !buts->buf_nr) 445 return -EINVAL; 446 447 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 448 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 449 450 /* 451 * some device names have larger paths - convert the slashes 452 * to underscores for this to work as expected 453 */ 454 for (i = 0; i < strlen(buts->name); i++) 455 if (buts->name[i] == '/') 456 buts->name[i] = '_'; 457 458 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 459 if (!bt) 460 return -ENOMEM; 461 462 ret = -ENOMEM; 463 bt->sequence = alloc_percpu(unsigned long); 464 if (!bt->sequence) 465 goto err; 466 467 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 468 if (!bt->msg_data) 469 goto err; 470 471 ret = -ENOENT; 472 473 mutex_lock(&blk_tree_mutex); 474 if (!blk_tree_root) { 475 blk_tree_root = debugfs_create_dir("block", NULL); 476 if (!blk_tree_root) { 477 mutex_unlock(&blk_tree_mutex); 478 goto err; 479 } 480 } 481 mutex_unlock(&blk_tree_mutex); 482 483 dir = debugfs_create_dir(buts->name, blk_tree_root); 484 485 if (!dir) 486 goto err; 487 488 bt->dir = dir; 489 bt->dev = dev; 490 atomic_set(&bt->dropped, 0); 491 INIT_LIST_HEAD(&bt->running_list); 492 493 ret = -EIO; 494 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 495 &blk_dropped_fops); 496 if (!bt->dropped_file) 497 goto err; 498 499 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 500 if (!bt->msg_file) 501 goto err; 502 503 bt->rchan = relay_open("trace", dir, buts->buf_size, 504 buts->buf_nr, &blk_relay_callbacks, bt); 505 if (!bt->rchan) 506 goto err; 507 508 bt->act_mask = buts->act_mask; 509 if (!bt->act_mask) 510 bt->act_mask = (u16) -1; 511 512 blk_trace_setup_lba(bt, bdev); 513 514 /* overwrite with user settings */ 515 if (buts->start_lba) 516 bt->start_lba = buts->start_lba; 517 if (buts->end_lba) 518 bt->end_lba = buts->end_lba; 519 520 bt->pid = buts->pid; 521 bt->trace_state = Blktrace_setup; 522 523 ret = -EBUSY; 524 old_bt = xchg(&q->blk_trace, bt); 525 if (old_bt) { 526 (void) xchg(&q->blk_trace, old_bt); 527 goto err; 528 } 529 530 if (atomic_inc_return(&blk_probes_ref) == 1) 531 blk_register_tracepoints(); 532 533 return 0; 534 err: 535 blk_trace_free(bt); 536 return ret; 537 } 538 539 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 540 struct block_device *bdev, 541 char __user *arg) 542 { 543 struct blk_user_trace_setup buts; 544 int ret; 545 546 ret = copy_from_user(&buts, arg, sizeof(buts)); 547 if (ret) 548 return -EFAULT; 549 550 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 551 if (ret) 552 return ret; 553 554 if (copy_to_user(arg, &buts, sizeof(buts))) { 555 blk_trace_remove(q); 556 return -EFAULT; 557 } 558 return 0; 559 } 560 EXPORT_SYMBOL_GPL(blk_trace_setup); 561 562 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 563 static int compat_blk_trace_setup(struct request_queue *q, char *name, 564 dev_t dev, struct block_device *bdev, 565 char __user *arg) 566 { 567 struct blk_user_trace_setup buts; 568 struct compat_blk_user_trace_setup cbuts; 569 int ret; 570 571 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 572 return -EFAULT; 573 574 buts = (struct blk_user_trace_setup) { 575 .act_mask = cbuts.act_mask, 576 .buf_size = cbuts.buf_size, 577 .buf_nr = cbuts.buf_nr, 578 .start_lba = cbuts.start_lba, 579 .end_lba = cbuts.end_lba, 580 .pid = cbuts.pid, 581 }; 582 583 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 584 if (ret) 585 return ret; 586 587 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) { 588 blk_trace_remove(q); 589 return -EFAULT; 590 } 591 592 return 0; 593 } 594 #endif 595 596 int blk_trace_startstop(struct request_queue *q, int start) 597 { 598 int ret; 599 struct blk_trace *bt = q->blk_trace; 600 601 if (bt == NULL) 602 return -EINVAL; 603 604 /* 605 * For starting a trace, we can transition from a setup or stopped 606 * trace. For stopping a trace, the state must be running 607 */ 608 ret = -EINVAL; 609 if (start) { 610 if (bt->trace_state == Blktrace_setup || 611 bt->trace_state == Blktrace_stopped) { 612 blktrace_seq++; 613 smp_mb(); 614 bt->trace_state = Blktrace_running; 615 spin_lock_irq(&running_trace_lock); 616 list_add(&bt->running_list, &running_trace_list); 617 spin_unlock_irq(&running_trace_lock); 618 619 trace_note_time(bt); 620 ret = 0; 621 } 622 } else { 623 if (bt->trace_state == Blktrace_running) { 624 bt->trace_state = Blktrace_stopped; 625 spin_lock_irq(&running_trace_lock); 626 list_del_init(&bt->running_list); 627 spin_unlock_irq(&running_trace_lock); 628 relay_flush(bt->rchan); 629 ret = 0; 630 } 631 } 632 633 return ret; 634 } 635 EXPORT_SYMBOL_GPL(blk_trace_startstop); 636 637 /** 638 * blk_trace_ioctl: - handle the ioctls associated with tracing 639 * @bdev: the block device 640 * @cmd: the ioctl cmd 641 * @arg: the argument data, if any 642 * 643 **/ 644 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 645 { 646 struct request_queue *q; 647 int ret, start = 0; 648 char b[BDEVNAME_SIZE]; 649 650 q = bdev_get_queue(bdev); 651 if (!q) 652 return -ENXIO; 653 654 mutex_lock(&bdev->bd_mutex); 655 656 switch (cmd) { 657 case BLKTRACESETUP: 658 bdevname(bdev, b); 659 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 660 break; 661 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 662 case BLKTRACESETUP32: 663 bdevname(bdev, b); 664 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 665 break; 666 #endif 667 case BLKTRACESTART: 668 start = 1; 669 case BLKTRACESTOP: 670 ret = blk_trace_startstop(q, start); 671 break; 672 case BLKTRACETEARDOWN: 673 ret = blk_trace_remove(q); 674 break; 675 default: 676 ret = -ENOTTY; 677 break; 678 } 679 680 mutex_unlock(&bdev->bd_mutex); 681 return ret; 682 } 683 684 /** 685 * blk_trace_shutdown: - stop and cleanup trace structures 686 * @q: the request queue associated with the device 687 * 688 **/ 689 void blk_trace_shutdown(struct request_queue *q) 690 { 691 if (q->blk_trace) { 692 blk_trace_startstop(q, 0); 693 blk_trace_remove(q); 694 } 695 } 696 697 /* 698 * blktrace probes 699 */ 700 701 /** 702 * blk_add_trace_rq - Add a trace for a request oriented action 703 * @q: queue the io is for 704 * @rq: the source request 705 * @what: the action 706 * 707 * Description: 708 * Records an action against a request. Will log the bio offset + size. 709 * 710 **/ 711 static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 712 u32 what) 713 { 714 struct blk_trace *bt = q->blk_trace; 715 716 if (likely(!bt)) 717 return; 718 719 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { 720 what |= BLK_TC_ACT(BLK_TC_PC); 721 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags, 722 what, rq->errors, rq->cmd_len, rq->cmd); 723 } else { 724 what |= BLK_TC_ACT(BLK_TC_FS); 725 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 726 rq->cmd_flags, what, rq->errors, 0, NULL); 727 } 728 } 729 730 static void blk_add_trace_rq_abort(void *ignore, 731 struct request_queue *q, struct request *rq) 732 { 733 blk_add_trace_rq(q, rq, BLK_TA_ABORT); 734 } 735 736 static void blk_add_trace_rq_insert(void *ignore, 737 struct request_queue *q, struct request *rq) 738 { 739 blk_add_trace_rq(q, rq, BLK_TA_INSERT); 740 } 741 742 static void blk_add_trace_rq_issue(void *ignore, 743 struct request_queue *q, struct request *rq) 744 { 745 blk_add_trace_rq(q, rq, BLK_TA_ISSUE); 746 } 747 748 static void blk_add_trace_rq_requeue(void *ignore, 749 struct request_queue *q, 750 struct request *rq) 751 { 752 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); 753 } 754 755 static void blk_add_trace_rq_complete(void *ignore, 756 struct request_queue *q, 757 struct request *rq) 758 { 759 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE); 760 } 761 762 /** 763 * blk_add_trace_bio - Add a trace for a bio oriented action 764 * @q: queue the io is for 765 * @bio: the source bio 766 * @what: the action 767 * @error: error, if any 768 * 769 * Description: 770 * Records an action against a bio. Will log the bio offset + size. 771 * 772 **/ 773 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 774 u32 what, int error) 775 { 776 struct blk_trace *bt = q->blk_trace; 777 778 if (likely(!bt)) 779 return; 780 781 if (!error && !bio_flagged(bio, BIO_UPTODATE)) 782 error = EIO; 783 784 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, 785 error, 0, NULL); 786 } 787 788 static void blk_add_trace_bio_bounce(void *ignore, 789 struct request_queue *q, struct bio *bio) 790 { 791 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0); 792 } 793 794 static void blk_add_trace_bio_complete(void *ignore, 795 struct request_queue *q, struct bio *bio, 796 int error) 797 { 798 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error); 799 } 800 801 static void blk_add_trace_bio_backmerge(void *ignore, 802 struct request_queue *q, 803 struct request *rq, 804 struct bio *bio) 805 { 806 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0); 807 } 808 809 static void blk_add_trace_bio_frontmerge(void *ignore, 810 struct request_queue *q, 811 struct request *rq, 812 struct bio *bio) 813 { 814 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0); 815 } 816 817 static void blk_add_trace_bio_queue(void *ignore, 818 struct request_queue *q, struct bio *bio) 819 { 820 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0); 821 } 822 823 static void blk_add_trace_getrq(void *ignore, 824 struct request_queue *q, 825 struct bio *bio, int rw) 826 { 827 if (bio) 828 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0); 829 else { 830 struct blk_trace *bt = q->blk_trace; 831 832 if (bt) 833 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); 834 } 835 } 836 837 838 static void blk_add_trace_sleeprq(void *ignore, 839 struct request_queue *q, 840 struct bio *bio, int rw) 841 { 842 if (bio) 843 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0); 844 else { 845 struct blk_trace *bt = q->blk_trace; 846 847 if (bt) 848 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 849 0, 0, NULL); 850 } 851 } 852 853 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 854 { 855 struct blk_trace *bt = q->blk_trace; 856 857 if (bt) 858 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 859 } 860 861 static void blk_add_trace_unplug(void *ignore, struct request_queue *q, 862 unsigned int depth, bool explicit) 863 { 864 struct blk_trace *bt = q->blk_trace; 865 866 if (bt) { 867 __be64 rpdu = cpu_to_be64(depth); 868 u32 what; 869 870 if (explicit) 871 what = BLK_TA_UNPLUG_IO; 872 else 873 what = BLK_TA_UNPLUG_TIMER; 874 875 __blk_add_trace(bt, 0, 0, 0, what, 0, 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(blk_add_trace_unplug, NULL); 1019 WARN_ON(ret); 1020 ret = register_trace_block_split(blk_add_trace_split, NULL); 1021 WARN_ON(ret); 1022 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1023 WARN_ON(ret); 1024 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1025 WARN_ON(ret); 1026 } 1027 1028 static void blk_unregister_tracepoints(void) 1029 { 1030 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1031 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1032 unregister_trace_block_split(blk_add_trace_split, NULL); 1033 unregister_trace_block_unplug(blk_add_trace_unplug, NULL); 1034 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1035 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1036 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1037 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1038 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1039 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1040 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1041 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1042 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1043 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1044 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1045 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1046 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 1047 1048 tracepoint_synchronize_unregister(); 1049 } 1050 1051 /* 1052 * struct blk_io_tracer formatting routines 1053 */ 1054 1055 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1056 { 1057 int i = 0; 1058 int tc = t->action >> BLK_TC_SHIFT; 1059 1060 if (t->action == BLK_TN_MESSAGE) { 1061 rwbs[i++] = 'N'; 1062 goto out; 1063 } 1064 1065 if (tc & BLK_TC_FLUSH) 1066 rwbs[i++] = 'F'; 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_FUA) 1078 rwbs[i++] = 'F'; 1079 if (tc & BLK_TC_AHEAD) 1080 rwbs[i++] = 'A'; 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[RWBS_LEN]; 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[RWBS_LEN]; 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 spin_lock_irq(&running_trace_lock); 1493 list_del(&bt->running_list); 1494 spin_unlock_irq(&running_trace_lock); 1495 blk_trace_free(bt); 1496 return 0; 1497 } 1498 1499 /* 1500 * Setup everything required to start tracing 1501 */ 1502 static int blk_trace_setup_queue(struct request_queue *q, 1503 struct block_device *bdev) 1504 { 1505 struct blk_trace *old_bt, *bt = NULL; 1506 int ret = -ENOMEM; 1507 1508 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1509 if (!bt) 1510 return -ENOMEM; 1511 1512 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1513 if (!bt->msg_data) 1514 goto free_bt; 1515 1516 bt->dev = bdev->bd_dev; 1517 bt->act_mask = (u16)-1; 1518 1519 blk_trace_setup_lba(bt, bdev); 1520 1521 old_bt = xchg(&q->blk_trace, bt); 1522 if (old_bt != NULL) { 1523 (void)xchg(&q->blk_trace, old_bt); 1524 ret = -EBUSY; 1525 goto free_bt; 1526 } 1527 1528 if (atomic_inc_return(&blk_probes_ref) == 1) 1529 blk_register_tracepoints(); 1530 return 0; 1531 1532 free_bt: 1533 blk_trace_free(bt); 1534 return ret; 1535 } 1536 1537 /* 1538 * sysfs interface to enable and configure tracing 1539 */ 1540 1541 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1542 struct device_attribute *attr, 1543 char *buf); 1544 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1545 struct device_attribute *attr, 1546 const char *buf, size_t count); 1547 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1548 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1549 sysfs_blk_trace_attr_show, \ 1550 sysfs_blk_trace_attr_store) 1551 1552 static BLK_TRACE_DEVICE_ATTR(enable); 1553 static BLK_TRACE_DEVICE_ATTR(act_mask); 1554 static BLK_TRACE_DEVICE_ATTR(pid); 1555 static BLK_TRACE_DEVICE_ATTR(start_lba); 1556 static BLK_TRACE_DEVICE_ATTR(end_lba); 1557 1558 static struct attribute *blk_trace_attrs[] = { 1559 &dev_attr_enable.attr, 1560 &dev_attr_act_mask.attr, 1561 &dev_attr_pid.attr, 1562 &dev_attr_start_lba.attr, 1563 &dev_attr_end_lba.attr, 1564 NULL 1565 }; 1566 1567 struct attribute_group blk_trace_attr_group = { 1568 .name = "trace", 1569 .attrs = blk_trace_attrs, 1570 }; 1571 1572 static const struct { 1573 int mask; 1574 const char *str; 1575 } mask_maps[] = { 1576 { BLK_TC_READ, "read" }, 1577 { BLK_TC_WRITE, "write" }, 1578 { BLK_TC_FLUSH, "flush" }, 1579 { BLK_TC_SYNC, "sync" }, 1580 { BLK_TC_QUEUE, "queue" }, 1581 { BLK_TC_REQUEUE, "requeue" }, 1582 { BLK_TC_ISSUE, "issue" }, 1583 { BLK_TC_COMPLETE, "complete" }, 1584 { BLK_TC_FS, "fs" }, 1585 { BLK_TC_PC, "pc" }, 1586 { BLK_TC_AHEAD, "ahead" }, 1587 { BLK_TC_META, "meta" }, 1588 { BLK_TC_DISCARD, "discard" }, 1589 { BLK_TC_DRV_DATA, "drv_data" }, 1590 { BLK_TC_FUA, "fua" }, 1591 }; 1592 1593 static int blk_trace_str2mask(const char *str) 1594 { 1595 int i; 1596 int mask = 0; 1597 char *buf, *s, *token; 1598 1599 buf = kstrdup(str, GFP_KERNEL); 1600 if (buf == NULL) 1601 return -ENOMEM; 1602 s = strstrip(buf); 1603 1604 while (1) { 1605 token = strsep(&s, ","); 1606 if (token == NULL) 1607 break; 1608 1609 if (*token == '\0') 1610 continue; 1611 1612 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1613 if (strcasecmp(token, mask_maps[i].str) == 0) { 1614 mask |= mask_maps[i].mask; 1615 break; 1616 } 1617 } 1618 if (i == ARRAY_SIZE(mask_maps)) { 1619 mask = -EINVAL; 1620 break; 1621 } 1622 } 1623 kfree(buf); 1624 1625 return mask; 1626 } 1627 1628 static ssize_t blk_trace_mask2str(char *buf, int mask) 1629 { 1630 int i; 1631 char *p = buf; 1632 1633 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1634 if (mask & mask_maps[i].mask) { 1635 p += sprintf(p, "%s%s", 1636 (p == buf) ? "" : ",", mask_maps[i].str); 1637 } 1638 } 1639 *p++ = '\n'; 1640 1641 return p - buf; 1642 } 1643 1644 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1645 { 1646 if (bdev->bd_disk == NULL) 1647 return NULL; 1648 1649 return bdev_get_queue(bdev); 1650 } 1651 1652 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1653 struct device_attribute *attr, 1654 char *buf) 1655 { 1656 struct hd_struct *p = dev_to_part(dev); 1657 struct request_queue *q; 1658 struct block_device *bdev; 1659 ssize_t ret = -ENXIO; 1660 1661 bdev = bdget(part_devt(p)); 1662 if (bdev == NULL) 1663 goto out; 1664 1665 q = blk_trace_get_queue(bdev); 1666 if (q == NULL) 1667 goto out_bdput; 1668 1669 mutex_lock(&bdev->bd_mutex); 1670 1671 if (attr == &dev_attr_enable) { 1672 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1673 goto out_unlock_bdev; 1674 } 1675 1676 if (q->blk_trace == NULL) 1677 ret = sprintf(buf, "disabled\n"); 1678 else if (attr == &dev_attr_act_mask) 1679 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1680 else if (attr == &dev_attr_pid) 1681 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1682 else if (attr == &dev_attr_start_lba) 1683 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1684 else if (attr == &dev_attr_end_lba) 1685 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1686 1687 out_unlock_bdev: 1688 mutex_unlock(&bdev->bd_mutex); 1689 out_bdput: 1690 bdput(bdev); 1691 out: 1692 return ret; 1693 } 1694 1695 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1696 struct device_attribute *attr, 1697 const char *buf, size_t count) 1698 { 1699 struct block_device *bdev; 1700 struct request_queue *q; 1701 struct hd_struct *p; 1702 u64 value; 1703 ssize_t ret = -EINVAL; 1704 1705 if (count == 0) 1706 goto out; 1707 1708 if (attr == &dev_attr_act_mask) { 1709 if (sscanf(buf, "%llx", &value) != 1) { 1710 /* Assume it is a list of trace category names */ 1711 ret = blk_trace_str2mask(buf); 1712 if (ret < 0) 1713 goto out; 1714 value = ret; 1715 } 1716 } else if (sscanf(buf, "%llu", &value) != 1) 1717 goto out; 1718 1719 ret = -ENXIO; 1720 1721 p = dev_to_part(dev); 1722 bdev = bdget(part_devt(p)); 1723 if (bdev == NULL) 1724 goto out; 1725 1726 q = blk_trace_get_queue(bdev); 1727 if (q == NULL) 1728 goto out_bdput; 1729 1730 mutex_lock(&bdev->bd_mutex); 1731 1732 if (attr == &dev_attr_enable) { 1733 if (value) 1734 ret = blk_trace_setup_queue(q, bdev); 1735 else 1736 ret = blk_trace_remove_queue(q); 1737 goto out_unlock_bdev; 1738 } 1739 1740 ret = 0; 1741 if (q->blk_trace == NULL) 1742 ret = blk_trace_setup_queue(q, bdev); 1743 1744 if (ret == 0) { 1745 if (attr == &dev_attr_act_mask) 1746 q->blk_trace->act_mask = value; 1747 else if (attr == &dev_attr_pid) 1748 q->blk_trace->pid = value; 1749 else if (attr == &dev_attr_start_lba) 1750 q->blk_trace->start_lba = value; 1751 else if (attr == &dev_attr_end_lba) 1752 q->blk_trace->end_lba = value; 1753 } 1754 1755 out_unlock_bdev: 1756 mutex_unlock(&bdev->bd_mutex); 1757 out_bdput: 1758 bdput(bdev); 1759 out: 1760 return ret ? ret : count; 1761 } 1762 1763 int blk_trace_init_sysfs(struct device *dev) 1764 { 1765 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1766 } 1767 1768 void blk_trace_remove_sysfs(struct device *dev) 1769 { 1770 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1771 } 1772 1773 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1774 1775 #ifdef CONFIG_EVENT_TRACING 1776 1777 void blk_dump_cmd(char *buf, struct request *rq) 1778 { 1779 int i, end; 1780 int len = rq->cmd_len; 1781 unsigned char *cmd = rq->cmd; 1782 1783 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) { 1784 buf[0] = '\0'; 1785 return; 1786 } 1787 1788 for (end = len - 1; end >= 0; end--) 1789 if (cmd[end]) 1790 break; 1791 end++; 1792 1793 for (i = 0; i < len; i++) { 1794 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1795 if (i == end && end != len - 1) { 1796 sprintf(buf, " .."); 1797 break; 1798 } 1799 } 1800 } 1801 1802 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) 1803 { 1804 int i = 0; 1805 1806 if (rw & REQ_FLUSH) 1807 rwbs[i++] = 'F'; 1808 1809 if (rw & WRITE) 1810 rwbs[i++] = 'W'; 1811 else if (rw & REQ_DISCARD) 1812 rwbs[i++] = 'D'; 1813 else if (bytes) 1814 rwbs[i++] = 'R'; 1815 else 1816 rwbs[i++] = 'N'; 1817 1818 if (rw & REQ_FUA) 1819 rwbs[i++] = 'F'; 1820 if (rw & REQ_RAHEAD) 1821 rwbs[i++] = 'A'; 1822 if (rw & REQ_SYNC) 1823 rwbs[i++] = 'S'; 1824 if (rw & REQ_META) 1825 rwbs[i++] = 'M'; 1826 if (rw & REQ_SECURE) 1827 rwbs[i++] = 'E'; 1828 1829 rwbs[i] = '\0'; 1830 } 1831 EXPORT_SYMBOL_GPL(blk_fill_rwbs); 1832 1833 #endif /* CONFIG_EVENT_TRACING */ 1834 1835