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_HARDBARRIER BLK_TC_BARRIER 172 #define BLK_TC_RAHEAD BLK_TC_AHEAD 173 174 /* The ilog2() calls fall out because they're constant */ 175 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \ 176 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name)) 177 178 /* 179 * The worker for the various blk_add_trace*() types. Fills out a 180 * blk_io_trace structure and places it in a per-cpu subbuffer. 181 */ 182 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 183 int rw, u32 what, int error, int pdu_len, void *pdu_data) 184 { 185 struct task_struct *tsk = current; 186 struct ring_buffer_event *event = NULL; 187 struct ring_buffer *buffer = NULL; 188 struct blk_io_trace *t; 189 unsigned long flags = 0; 190 unsigned long *sequence; 191 pid_t pid; 192 int cpu, pc = 0; 193 bool blk_tracer = blk_tracer_enabled; 194 195 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 196 return; 197 198 what |= ddir_act[rw & WRITE]; 199 what |= MASK_TC_BIT(rw, HARDBARRIER); 200 what |= MASK_TC_BIT(rw, SYNC); 201 what |= MASK_TC_BIT(rw, RAHEAD); 202 what |= MASK_TC_BIT(rw, META); 203 what |= MASK_TC_BIT(rw, DISCARD); 204 205 pid = tsk->pid; 206 if (act_log_check(bt, what, sector, pid)) 207 return; 208 cpu = raw_smp_processor_id(); 209 210 if (blk_tracer) { 211 tracing_record_cmdline(current); 212 213 buffer = blk_tr->buffer; 214 pc = preempt_count(); 215 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 216 sizeof(*t) + pdu_len, 217 0, pc); 218 if (!event) 219 return; 220 t = ring_buffer_event_data(event); 221 goto record_it; 222 } 223 224 /* 225 * A word about the locking here - we disable interrupts to reserve 226 * some space in the relay per-cpu buffer, to prevent an irq 227 * from coming in and stepping on our toes. 228 */ 229 local_irq_save(flags); 230 231 if (unlikely(tsk->btrace_seq != blktrace_seq)) 232 trace_note_tsk(bt, tsk); 233 234 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 235 if (t) { 236 sequence = per_cpu_ptr(bt->sequence, cpu); 237 238 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 239 t->sequence = ++(*sequence); 240 t->time = ktime_to_ns(ktime_get()); 241 record_it: 242 /* 243 * These two are not needed in ftrace as they are in the 244 * generic trace_entry, filled by tracing_generic_entry_update, 245 * but for the trace_event->bin() synthesizer benefit we do it 246 * here too. 247 */ 248 t->cpu = cpu; 249 t->pid = pid; 250 251 t->sector = sector; 252 t->bytes = bytes; 253 t->action = what; 254 t->device = bt->dev; 255 t->error = error; 256 t->pdu_len = pdu_len; 257 258 if (pdu_len) 259 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 260 261 if (blk_tracer) { 262 trace_buffer_unlock_commit(buffer, event, 0, pc); 263 return; 264 } 265 } 266 267 local_irq_restore(flags); 268 } 269 270 static struct dentry *blk_tree_root; 271 static DEFINE_MUTEX(blk_tree_mutex); 272 273 static void blk_trace_free(struct blk_trace *bt) 274 { 275 debugfs_remove(bt->msg_file); 276 debugfs_remove(bt->dropped_file); 277 relay_close(bt->rchan); 278 debugfs_remove(bt->dir); 279 free_percpu(bt->sequence); 280 free_percpu(bt->msg_data); 281 kfree(bt); 282 } 283 284 static void blk_trace_cleanup(struct blk_trace *bt) 285 { 286 blk_trace_free(bt); 287 if (atomic_dec_and_test(&blk_probes_ref)) 288 blk_unregister_tracepoints(); 289 } 290 291 int blk_trace_remove(struct request_queue *q) 292 { 293 struct blk_trace *bt; 294 295 bt = xchg(&q->blk_trace, NULL); 296 if (!bt) 297 return -EINVAL; 298 299 if (bt->trace_state != Blktrace_running) 300 blk_trace_cleanup(bt); 301 302 return 0; 303 } 304 EXPORT_SYMBOL_GPL(blk_trace_remove); 305 306 static int blk_dropped_open(struct inode *inode, struct file *filp) 307 { 308 filp->private_data = inode->i_private; 309 310 return 0; 311 } 312 313 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 314 size_t count, loff_t *ppos) 315 { 316 struct blk_trace *bt = filp->private_data; 317 char buf[16]; 318 319 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 320 321 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 322 } 323 324 static const struct file_operations blk_dropped_fops = { 325 .owner = THIS_MODULE, 326 .open = blk_dropped_open, 327 .read = blk_dropped_read, 328 .llseek = default_llseek, 329 }; 330 331 static int blk_msg_open(struct inode *inode, struct file *filp) 332 { 333 filp->private_data = inode->i_private; 334 335 return 0; 336 } 337 338 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 339 size_t count, loff_t *ppos) 340 { 341 char *msg; 342 struct blk_trace *bt; 343 344 if (count >= BLK_TN_MAX_MSG) 345 return -EINVAL; 346 347 msg = kmalloc(count + 1, GFP_KERNEL); 348 if (msg == NULL) 349 return -ENOMEM; 350 351 if (copy_from_user(msg, buffer, count)) { 352 kfree(msg); 353 return -EFAULT; 354 } 355 356 msg[count] = '\0'; 357 bt = filp->private_data; 358 __trace_note_message(bt, "%s", msg); 359 kfree(msg); 360 361 return count; 362 } 363 364 static const struct file_operations blk_msg_fops = { 365 .owner = THIS_MODULE, 366 .open = blk_msg_open, 367 .write = blk_msg_write, 368 .llseek = noop_llseek, 369 }; 370 371 /* 372 * Keep track of how many times we encountered a full subbuffer, to aid 373 * the user space app in telling how many lost events there were. 374 */ 375 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 376 void *prev_subbuf, size_t prev_padding) 377 { 378 struct blk_trace *bt; 379 380 if (!relay_buf_full(buf)) 381 return 1; 382 383 bt = buf->chan->private_data; 384 atomic_inc(&bt->dropped); 385 return 0; 386 } 387 388 static int blk_remove_buf_file_callback(struct dentry *dentry) 389 { 390 debugfs_remove(dentry); 391 392 return 0; 393 } 394 395 static struct dentry *blk_create_buf_file_callback(const char *filename, 396 struct dentry *parent, 397 int mode, 398 struct rchan_buf *buf, 399 int *is_global) 400 { 401 return debugfs_create_file(filename, mode, parent, buf, 402 &relay_file_operations); 403 } 404 405 static struct rchan_callbacks blk_relay_callbacks = { 406 .subbuf_start = blk_subbuf_start_callback, 407 .create_buf_file = blk_create_buf_file_callback, 408 .remove_buf_file = blk_remove_buf_file_callback, 409 }; 410 411 static void blk_trace_setup_lba(struct blk_trace *bt, 412 struct block_device *bdev) 413 { 414 struct hd_struct *part = NULL; 415 416 if (bdev) 417 part = bdev->bd_part; 418 419 if (part) { 420 bt->start_lba = part->start_sect; 421 bt->end_lba = part->start_sect + part->nr_sects; 422 } else { 423 bt->start_lba = 0; 424 bt->end_lba = -1ULL; 425 } 426 } 427 428 /* 429 * Setup everything required to start tracing 430 */ 431 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 432 struct block_device *bdev, 433 struct blk_user_trace_setup *buts) 434 { 435 struct blk_trace *old_bt, *bt = NULL; 436 struct dentry *dir = NULL; 437 int ret, i; 438 439 if (!buts->buf_size || !buts->buf_nr) 440 return -EINVAL; 441 442 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 443 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 444 445 /* 446 * some device names have larger paths - convert the slashes 447 * to underscores for this to work as expected 448 */ 449 for (i = 0; i < strlen(buts->name); i++) 450 if (buts->name[i] == '/') 451 buts->name[i] = '_'; 452 453 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 454 if (!bt) 455 return -ENOMEM; 456 457 ret = -ENOMEM; 458 bt->sequence = alloc_percpu(unsigned long); 459 if (!bt->sequence) 460 goto err; 461 462 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 463 if (!bt->msg_data) 464 goto err; 465 466 ret = -ENOENT; 467 468 mutex_lock(&blk_tree_mutex); 469 if (!blk_tree_root) { 470 blk_tree_root = debugfs_create_dir("block", NULL); 471 if (!blk_tree_root) { 472 mutex_unlock(&blk_tree_mutex); 473 goto err; 474 } 475 } 476 mutex_unlock(&blk_tree_mutex); 477 478 dir = debugfs_create_dir(buts->name, blk_tree_root); 479 480 if (!dir) 481 goto err; 482 483 bt->dir = dir; 484 bt->dev = dev; 485 atomic_set(&bt->dropped, 0); 486 487 ret = -EIO; 488 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 489 &blk_dropped_fops); 490 if (!bt->dropped_file) 491 goto err; 492 493 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 494 if (!bt->msg_file) 495 goto err; 496 497 bt->rchan = relay_open("trace", dir, buts->buf_size, 498 buts->buf_nr, &blk_relay_callbacks, bt); 499 if (!bt->rchan) 500 goto err; 501 502 bt->act_mask = buts->act_mask; 503 if (!bt->act_mask) 504 bt->act_mask = (u16) -1; 505 506 blk_trace_setup_lba(bt, bdev); 507 508 /* overwrite with user settings */ 509 if (buts->start_lba) 510 bt->start_lba = buts->start_lba; 511 if (buts->end_lba) 512 bt->end_lba = buts->end_lba; 513 514 bt->pid = buts->pid; 515 bt->trace_state = Blktrace_setup; 516 517 ret = -EBUSY; 518 old_bt = xchg(&q->blk_trace, bt); 519 if (old_bt) { 520 (void) xchg(&q->blk_trace, old_bt); 521 goto err; 522 } 523 524 if (atomic_inc_return(&blk_probes_ref) == 1) 525 blk_register_tracepoints(); 526 527 return 0; 528 err: 529 blk_trace_free(bt); 530 return ret; 531 } 532 533 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 534 struct block_device *bdev, 535 char __user *arg) 536 { 537 struct blk_user_trace_setup buts; 538 int ret; 539 540 ret = copy_from_user(&buts, arg, sizeof(buts)); 541 if (ret) 542 return -EFAULT; 543 544 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 545 if (ret) 546 return ret; 547 548 if (copy_to_user(arg, &buts, sizeof(buts))) { 549 blk_trace_remove(q); 550 return -EFAULT; 551 } 552 return 0; 553 } 554 EXPORT_SYMBOL_GPL(blk_trace_setup); 555 556 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 557 static int compat_blk_trace_setup(struct request_queue *q, char *name, 558 dev_t dev, struct block_device *bdev, 559 char __user *arg) 560 { 561 struct blk_user_trace_setup buts; 562 struct compat_blk_user_trace_setup cbuts; 563 int ret; 564 565 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 566 return -EFAULT; 567 568 buts = (struct blk_user_trace_setup) { 569 .act_mask = cbuts.act_mask, 570 .buf_size = cbuts.buf_size, 571 .buf_nr = cbuts.buf_nr, 572 .start_lba = cbuts.start_lba, 573 .end_lba = cbuts.end_lba, 574 .pid = cbuts.pid, 575 }; 576 memcpy(&buts.name, &cbuts.name, 32); 577 578 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 579 if (ret) 580 return ret; 581 582 if (copy_to_user(arg, &buts.name, 32)) { 583 blk_trace_remove(q); 584 return -EFAULT; 585 } 586 587 return 0; 588 } 589 #endif 590 591 int blk_trace_startstop(struct request_queue *q, int start) 592 { 593 int ret; 594 struct blk_trace *bt = q->blk_trace; 595 596 if (bt == NULL) 597 return -EINVAL; 598 599 /* 600 * For starting a trace, we can transition from a setup or stopped 601 * trace. For stopping a trace, the state must be running 602 */ 603 ret = -EINVAL; 604 if (start) { 605 if (bt->trace_state == Blktrace_setup || 606 bt->trace_state == Blktrace_stopped) { 607 blktrace_seq++; 608 smp_mb(); 609 bt->trace_state = Blktrace_running; 610 611 trace_note_time(bt); 612 ret = 0; 613 } 614 } else { 615 if (bt->trace_state == Blktrace_running) { 616 bt->trace_state = Blktrace_stopped; 617 relay_flush(bt->rchan); 618 ret = 0; 619 } 620 } 621 622 return ret; 623 } 624 EXPORT_SYMBOL_GPL(blk_trace_startstop); 625 626 /** 627 * blk_trace_ioctl: - handle the ioctls associated with tracing 628 * @bdev: the block device 629 * @cmd: the ioctl cmd 630 * @arg: the argument data, if any 631 * 632 **/ 633 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 634 { 635 struct request_queue *q; 636 int ret, start = 0; 637 char b[BDEVNAME_SIZE]; 638 639 q = bdev_get_queue(bdev); 640 if (!q) 641 return -ENXIO; 642 643 mutex_lock(&bdev->bd_mutex); 644 645 switch (cmd) { 646 case BLKTRACESETUP: 647 bdevname(bdev, b); 648 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 649 break; 650 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 651 case BLKTRACESETUP32: 652 bdevname(bdev, b); 653 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 654 break; 655 #endif 656 case BLKTRACESTART: 657 start = 1; 658 case BLKTRACESTOP: 659 ret = blk_trace_startstop(q, start); 660 break; 661 case BLKTRACETEARDOWN: 662 ret = blk_trace_remove(q); 663 break; 664 default: 665 ret = -ENOTTY; 666 break; 667 } 668 669 mutex_unlock(&bdev->bd_mutex); 670 return ret; 671 } 672 673 /** 674 * blk_trace_shutdown: - stop and cleanup trace structures 675 * @q: the request queue associated with the device 676 * 677 **/ 678 void blk_trace_shutdown(struct request_queue *q) 679 { 680 if (q->blk_trace) { 681 blk_trace_startstop(q, 0); 682 blk_trace_remove(q); 683 } 684 } 685 686 /* 687 * blktrace probes 688 */ 689 690 /** 691 * blk_add_trace_rq - Add a trace for a request oriented action 692 * @q: queue the io is for 693 * @rq: the source request 694 * @what: the action 695 * 696 * Description: 697 * Records an action against a request. Will log the bio offset + size. 698 * 699 **/ 700 static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 701 u32 what) 702 { 703 struct blk_trace *bt = q->blk_trace; 704 int rw = rq->cmd_flags & 0x03; 705 706 if (likely(!bt)) 707 return; 708 709 if (rq->cmd_flags & REQ_DISCARD) 710 rw |= REQ_DISCARD; 711 712 if (rq->cmd_flags & REQ_SECURE) 713 rw |= REQ_SECURE; 714 715 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { 716 what |= BLK_TC_ACT(BLK_TC_PC); 717 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw, 718 what, rq->errors, rq->cmd_len, rq->cmd); 719 } else { 720 what |= BLK_TC_ACT(BLK_TC_FS); 721 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw, 722 what, rq->errors, 0, NULL); 723 } 724 } 725 726 static void blk_add_trace_rq_abort(void *ignore, 727 struct request_queue *q, struct request *rq) 728 { 729 blk_add_trace_rq(q, rq, BLK_TA_ABORT); 730 } 731 732 static void blk_add_trace_rq_insert(void *ignore, 733 struct request_queue *q, struct request *rq) 734 { 735 blk_add_trace_rq(q, rq, BLK_TA_INSERT); 736 } 737 738 static void blk_add_trace_rq_issue(void *ignore, 739 struct request_queue *q, struct request *rq) 740 { 741 blk_add_trace_rq(q, rq, BLK_TA_ISSUE); 742 } 743 744 static void blk_add_trace_rq_requeue(void *ignore, 745 struct request_queue *q, 746 struct request *rq) 747 { 748 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); 749 } 750 751 static void blk_add_trace_rq_complete(void *ignore, 752 struct request_queue *q, 753 struct request *rq) 754 { 755 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE); 756 } 757 758 /** 759 * blk_add_trace_bio - Add a trace for a bio oriented action 760 * @q: queue the io is for 761 * @bio: the source bio 762 * @what: the action 763 * 764 * Description: 765 * Records an action against a bio. Will log the bio offset + size. 766 * 767 **/ 768 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 769 u32 what) 770 { 771 struct blk_trace *bt = q->blk_trace; 772 773 if (likely(!bt)) 774 return; 775 776 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, 777 !bio_flagged(bio, BIO_UPTODATE), 0, NULL); 778 } 779 780 static void blk_add_trace_bio_bounce(void *ignore, 781 struct request_queue *q, struct bio *bio) 782 { 783 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE); 784 } 785 786 static void blk_add_trace_bio_complete(void *ignore, 787 struct request_queue *q, struct bio *bio) 788 { 789 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE); 790 } 791 792 static void blk_add_trace_bio_backmerge(void *ignore, 793 struct request_queue *q, 794 struct bio *bio) 795 { 796 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE); 797 } 798 799 static void blk_add_trace_bio_frontmerge(void *ignore, 800 struct request_queue *q, 801 struct bio *bio) 802 { 803 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE); 804 } 805 806 static void blk_add_trace_bio_queue(void *ignore, 807 struct request_queue *q, struct bio *bio) 808 { 809 blk_add_trace_bio(q, bio, BLK_TA_QUEUE); 810 } 811 812 static void blk_add_trace_getrq(void *ignore, 813 struct request_queue *q, 814 struct bio *bio, int rw) 815 { 816 if (bio) 817 blk_add_trace_bio(q, bio, BLK_TA_GETRQ); 818 else { 819 struct blk_trace *bt = q->blk_trace; 820 821 if (bt) 822 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); 823 } 824 } 825 826 827 static void blk_add_trace_sleeprq(void *ignore, 828 struct request_queue *q, 829 struct bio *bio, int rw) 830 { 831 if (bio) 832 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ); 833 else { 834 struct blk_trace *bt = q->blk_trace; 835 836 if (bt) 837 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 838 0, 0, NULL); 839 } 840 } 841 842 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 843 { 844 struct blk_trace *bt = q->blk_trace; 845 846 if (bt) 847 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 848 } 849 850 static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q) 851 { 852 struct blk_trace *bt = q->blk_trace; 853 854 if (bt) { 855 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 856 __be64 rpdu = cpu_to_be64(pdu); 857 858 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0, 859 sizeof(rpdu), &rpdu); 860 } 861 } 862 863 static void blk_add_trace_unplug_timer(void *ignore, struct request_queue *q) 864 { 865 struct blk_trace *bt = q->blk_trace; 866 867 if (bt) { 868 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 869 __be64 rpdu = cpu_to_be64(pdu); 870 871 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0, 872 sizeof(rpdu), &rpdu); 873 } 874 } 875 876 static void blk_add_trace_split(void *ignore, 877 struct request_queue *q, struct bio *bio, 878 unsigned int pdu) 879 { 880 struct blk_trace *bt = q->blk_trace; 881 882 if (bt) { 883 __be64 rpdu = cpu_to_be64(pdu); 884 885 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 886 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE), 887 sizeof(rpdu), &rpdu); 888 } 889 } 890 891 /** 892 * blk_add_trace_remap - Add a trace for a remap operation 893 * @ignore: trace callback data parameter (not used) 894 * @q: queue the io is for 895 * @bio: the source bio 896 * @dev: target device 897 * @from: source sector 898 * 899 * Description: 900 * Device mapper or raid target sometimes need to split a bio because 901 * it spans a stripe (or similar). Add a trace for that action. 902 * 903 **/ 904 static void blk_add_trace_remap(void *ignore, 905 struct request_queue *q, struct bio *bio, 906 dev_t dev, sector_t from) 907 { 908 struct blk_trace *bt = q->blk_trace; 909 struct blk_io_trace_remap r; 910 911 if (likely(!bt)) 912 return; 913 914 r.device_from = cpu_to_be32(dev); 915 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 916 r.sector_from = cpu_to_be64(from); 917 918 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 919 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), 920 sizeof(r), &r); 921 } 922 923 /** 924 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 925 * @ignore: trace callback data parameter (not used) 926 * @q: queue the io is for 927 * @rq: the source request 928 * @dev: target device 929 * @from: source sector 930 * 931 * Description: 932 * Device mapper remaps request to other devices. 933 * Add a trace for that action. 934 * 935 **/ 936 static void blk_add_trace_rq_remap(void *ignore, 937 struct request_queue *q, 938 struct request *rq, dev_t dev, 939 sector_t from) 940 { 941 struct blk_trace *bt = q->blk_trace; 942 struct blk_io_trace_remap r; 943 944 if (likely(!bt)) 945 return; 946 947 r.device_from = cpu_to_be32(dev); 948 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 949 r.sector_from = cpu_to_be64(from); 950 951 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 952 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors, 953 sizeof(r), &r); 954 } 955 956 /** 957 * blk_add_driver_data - Add binary message with driver-specific data 958 * @q: queue the io is for 959 * @rq: io request 960 * @data: driver-specific data 961 * @len: length of driver-specific data 962 * 963 * Description: 964 * Some drivers might want to write driver-specific data per request. 965 * 966 **/ 967 void blk_add_driver_data(struct request_queue *q, 968 struct request *rq, 969 void *data, size_t len) 970 { 971 struct blk_trace *bt = q->blk_trace; 972 973 if (likely(!bt)) 974 return; 975 976 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) 977 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 978 BLK_TA_DRV_DATA, rq->errors, len, data); 979 else 980 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 981 BLK_TA_DRV_DATA, rq->errors, len, data); 982 } 983 EXPORT_SYMBOL_GPL(blk_add_driver_data); 984 985 static void blk_register_tracepoints(void) 986 { 987 int ret; 988 989 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 990 WARN_ON(ret); 991 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 992 WARN_ON(ret); 993 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 994 WARN_ON(ret); 995 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 996 WARN_ON(ret); 997 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 998 WARN_ON(ret); 999 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1000 WARN_ON(ret); 1001 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1002 WARN_ON(ret); 1003 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1004 WARN_ON(ret); 1005 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1006 WARN_ON(ret); 1007 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1008 WARN_ON(ret); 1009 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 1010 WARN_ON(ret); 1011 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1012 WARN_ON(ret); 1013 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 1014 WARN_ON(ret); 1015 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL); 1016 WARN_ON(ret); 1017 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); 1018 WARN_ON(ret); 1019 ret = register_trace_block_split(blk_add_trace_split, NULL); 1020 WARN_ON(ret); 1021 ret = register_trace_block_remap(blk_add_trace_remap, NULL); 1022 WARN_ON(ret); 1023 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1024 WARN_ON(ret); 1025 } 1026 1027 static void blk_unregister_tracepoints(void) 1028 { 1029 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1030 unregister_trace_block_remap(blk_add_trace_remap, NULL); 1031 unregister_trace_block_split(blk_add_trace_split, NULL); 1032 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); 1033 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, 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_DISCARD) 1066 rwbs[i++] = 'D'; 1067 else if (tc & BLK_TC_WRITE) 1068 rwbs[i++] = 'W'; 1069 else if (t->bytes) 1070 rwbs[i++] = 'R'; 1071 else 1072 rwbs[i++] = 'N'; 1073 1074 if (tc & BLK_TC_AHEAD) 1075 rwbs[i++] = 'A'; 1076 if (tc & BLK_TC_BARRIER) 1077 rwbs[i++] = 'B'; 1078 if (tc & BLK_TC_SYNC) 1079 rwbs[i++] = 'S'; 1080 if (tc & BLK_TC_META) 1081 rwbs[i++] = 'M'; 1082 out: 1083 rwbs[i] = '\0'; 1084 } 1085 1086 static inline 1087 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1088 { 1089 return (const struct blk_io_trace *)ent; 1090 } 1091 1092 static inline const void *pdu_start(const struct trace_entry *ent) 1093 { 1094 return te_blk_io_trace(ent) + 1; 1095 } 1096 1097 static inline u32 t_action(const struct trace_entry *ent) 1098 { 1099 return te_blk_io_trace(ent)->action; 1100 } 1101 1102 static inline u32 t_bytes(const struct trace_entry *ent) 1103 { 1104 return te_blk_io_trace(ent)->bytes; 1105 } 1106 1107 static inline u32 t_sec(const struct trace_entry *ent) 1108 { 1109 return te_blk_io_trace(ent)->bytes >> 9; 1110 } 1111 1112 static inline unsigned long long t_sector(const struct trace_entry *ent) 1113 { 1114 return te_blk_io_trace(ent)->sector; 1115 } 1116 1117 static inline __u16 t_error(const struct trace_entry *ent) 1118 { 1119 return te_blk_io_trace(ent)->error; 1120 } 1121 1122 static __u64 get_pdu_int(const struct trace_entry *ent) 1123 { 1124 const __u64 *val = pdu_start(ent); 1125 return be64_to_cpu(*val); 1126 } 1127 1128 static void get_pdu_remap(const struct trace_entry *ent, 1129 struct blk_io_trace_remap *r) 1130 { 1131 const struct blk_io_trace_remap *__r = pdu_start(ent); 1132 __u64 sector_from = __r->sector_from; 1133 1134 r->device_from = be32_to_cpu(__r->device_from); 1135 r->device_to = be32_to_cpu(__r->device_to); 1136 r->sector_from = be64_to_cpu(sector_from); 1137 } 1138 1139 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1140 1141 static int blk_log_action_classic(struct trace_iterator *iter, const char *act) 1142 { 1143 char rwbs[6]; 1144 unsigned long long ts = iter->ts; 1145 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1146 unsigned secs = (unsigned long)ts; 1147 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1148 1149 fill_rwbs(rwbs, t); 1150 1151 return trace_seq_printf(&iter->seq, 1152 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1153 MAJOR(t->device), MINOR(t->device), iter->cpu, 1154 secs, nsec_rem, iter->ent->pid, act, rwbs); 1155 } 1156 1157 static int blk_log_action(struct trace_iterator *iter, const char *act) 1158 { 1159 char rwbs[6]; 1160 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1161 1162 fill_rwbs(rwbs, t); 1163 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1164 MAJOR(t->device), MINOR(t->device), act, rwbs); 1165 } 1166 1167 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1168 { 1169 const unsigned char *pdu_buf; 1170 int pdu_len; 1171 int i, end, ret; 1172 1173 pdu_buf = pdu_start(ent); 1174 pdu_len = te_blk_io_trace(ent)->pdu_len; 1175 1176 if (!pdu_len) 1177 return 1; 1178 1179 /* find the last zero that needs to be printed */ 1180 for (end = pdu_len - 1; end >= 0; end--) 1181 if (pdu_buf[end]) 1182 break; 1183 end++; 1184 1185 if (!trace_seq_putc(s, '(')) 1186 return 0; 1187 1188 for (i = 0; i < pdu_len; i++) { 1189 1190 ret = trace_seq_printf(s, "%s%02x", 1191 i == 0 ? "" : " ", pdu_buf[i]); 1192 if (!ret) 1193 return ret; 1194 1195 /* 1196 * stop when the rest is just zeroes and indicate so 1197 * with a ".." appended 1198 */ 1199 if (i == end && end != pdu_len - 1) 1200 return trace_seq_puts(s, " ..) "); 1201 } 1202 1203 return trace_seq_puts(s, ") "); 1204 } 1205 1206 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1207 { 1208 char cmd[TASK_COMM_LEN]; 1209 1210 trace_find_cmdline(ent->pid, cmd); 1211 1212 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1213 int ret; 1214 1215 ret = trace_seq_printf(s, "%u ", t_bytes(ent)); 1216 if (!ret) 1217 return 0; 1218 ret = blk_log_dump_pdu(s, ent); 1219 if (!ret) 1220 return 0; 1221 return trace_seq_printf(s, "[%s]\n", cmd); 1222 } else { 1223 if (t_sec(ent)) 1224 return trace_seq_printf(s, "%llu + %u [%s]\n", 1225 t_sector(ent), t_sec(ent), cmd); 1226 return trace_seq_printf(s, "[%s]\n", cmd); 1227 } 1228 } 1229 1230 static int blk_log_with_error(struct trace_seq *s, 1231 const struct trace_entry *ent) 1232 { 1233 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1234 int ret; 1235 1236 ret = blk_log_dump_pdu(s, ent); 1237 if (ret) 1238 return trace_seq_printf(s, "[%d]\n", t_error(ent)); 1239 return 0; 1240 } else { 1241 if (t_sec(ent)) 1242 return trace_seq_printf(s, "%llu + %u [%d]\n", 1243 t_sector(ent), 1244 t_sec(ent), t_error(ent)); 1245 return trace_seq_printf(s, "%llu [%d]\n", 1246 t_sector(ent), t_error(ent)); 1247 } 1248 } 1249 1250 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1251 { 1252 struct blk_io_trace_remap r = { .device_from = 0, }; 1253 1254 get_pdu_remap(ent, &r); 1255 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1256 t_sector(ent), t_sec(ent), 1257 MAJOR(r.device_from), MINOR(r.device_from), 1258 (unsigned long long)r.sector_from); 1259 } 1260 1261 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1262 { 1263 char cmd[TASK_COMM_LEN]; 1264 1265 trace_find_cmdline(ent->pid, cmd); 1266 1267 return trace_seq_printf(s, "[%s]\n", cmd); 1268 } 1269 1270 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1271 { 1272 char cmd[TASK_COMM_LEN]; 1273 1274 trace_find_cmdline(ent->pid, cmd); 1275 1276 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1277 } 1278 1279 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1280 { 1281 char cmd[TASK_COMM_LEN]; 1282 1283 trace_find_cmdline(ent->pid, cmd); 1284 1285 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1286 get_pdu_int(ent), cmd); 1287 } 1288 1289 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1290 { 1291 int ret; 1292 const struct blk_io_trace *t = te_blk_io_trace(ent); 1293 1294 ret = trace_seq_putmem(s, t + 1, t->pdu_len); 1295 if (ret) 1296 return trace_seq_putc(s, '\n'); 1297 return ret; 1298 } 1299 1300 /* 1301 * struct tracer operations 1302 */ 1303 1304 static void blk_tracer_print_header(struct seq_file *m) 1305 { 1306 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1307 return; 1308 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1309 "# | | | | | |\n"); 1310 } 1311 1312 static void blk_tracer_start(struct trace_array *tr) 1313 { 1314 blk_tracer_enabled = true; 1315 } 1316 1317 static int blk_tracer_init(struct trace_array *tr) 1318 { 1319 blk_tr = tr; 1320 blk_tracer_start(tr); 1321 return 0; 1322 } 1323 1324 static void blk_tracer_stop(struct trace_array *tr) 1325 { 1326 blk_tracer_enabled = false; 1327 } 1328 1329 static void blk_tracer_reset(struct trace_array *tr) 1330 { 1331 blk_tracer_stop(tr); 1332 } 1333 1334 static const struct { 1335 const char *act[2]; 1336 int (*print)(struct trace_seq *s, const struct trace_entry *ent); 1337 } what2act[] = { 1338 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1339 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1340 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1341 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1342 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1343 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1344 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1345 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1346 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1347 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1348 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1349 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1350 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1351 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1352 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1353 }; 1354 1355 static enum print_line_t print_one_line(struct trace_iterator *iter, 1356 bool classic) 1357 { 1358 struct trace_seq *s = &iter->seq; 1359 const struct blk_io_trace *t; 1360 u16 what; 1361 int ret; 1362 bool long_act; 1363 blk_log_action_t *log_action; 1364 1365 t = te_blk_io_trace(iter->ent); 1366 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1367 long_act = !!(trace_flags & TRACE_ITER_VERBOSE); 1368 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1369 1370 if (t->action == BLK_TN_MESSAGE) { 1371 ret = log_action(iter, long_act ? "message" : "m"); 1372 if (ret) 1373 ret = blk_log_msg(s, iter->ent); 1374 goto out; 1375 } 1376 1377 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1378 ret = trace_seq_printf(s, "Unknown action %x\n", what); 1379 else { 1380 ret = log_action(iter, what2act[what].act[long_act]); 1381 if (ret) 1382 ret = what2act[what].print(s, iter->ent); 1383 } 1384 out: 1385 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1386 } 1387 1388 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1389 int flags, struct trace_event *event) 1390 { 1391 return print_one_line(iter, false); 1392 } 1393 1394 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1395 { 1396 struct trace_seq *s = &iter->seq; 1397 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1398 const int offset = offsetof(struct blk_io_trace, sector); 1399 struct blk_io_trace old = { 1400 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1401 .time = iter->ts, 1402 }; 1403 1404 if (!trace_seq_putmem(s, &old, offset)) 1405 return 0; 1406 return trace_seq_putmem(s, &t->sector, 1407 sizeof(old) - offset + t->pdu_len); 1408 } 1409 1410 static enum print_line_t 1411 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1412 struct trace_event *event) 1413 { 1414 return blk_trace_synthesize_old_trace(iter) ? 1415 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1416 } 1417 1418 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1419 { 1420 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1421 return TRACE_TYPE_UNHANDLED; 1422 1423 return print_one_line(iter, true); 1424 } 1425 1426 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set) 1427 { 1428 /* don't output context-info for blk_classic output */ 1429 if (bit == TRACE_BLK_OPT_CLASSIC) { 1430 if (set) 1431 trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1432 else 1433 trace_flags |= TRACE_ITER_CONTEXT_INFO; 1434 } 1435 return 0; 1436 } 1437 1438 static struct tracer blk_tracer __read_mostly = { 1439 .name = "blk", 1440 .init = blk_tracer_init, 1441 .reset = blk_tracer_reset, 1442 .start = blk_tracer_start, 1443 .stop = blk_tracer_stop, 1444 .print_header = blk_tracer_print_header, 1445 .print_line = blk_tracer_print_line, 1446 .flags = &blk_tracer_flags, 1447 .set_flag = blk_tracer_set_flag, 1448 }; 1449 1450 static struct trace_event_functions trace_blk_event_funcs = { 1451 .trace = blk_trace_event_print, 1452 .binary = blk_trace_event_print_binary, 1453 }; 1454 1455 static struct trace_event trace_blk_event = { 1456 .type = TRACE_BLK, 1457 .funcs = &trace_blk_event_funcs, 1458 }; 1459 1460 static int __init init_blk_tracer(void) 1461 { 1462 if (!register_ftrace_event(&trace_blk_event)) { 1463 pr_warning("Warning: could not register block events\n"); 1464 return 1; 1465 } 1466 1467 if (register_tracer(&blk_tracer) != 0) { 1468 pr_warning("Warning: could not register the block tracer\n"); 1469 unregister_ftrace_event(&trace_blk_event); 1470 return 1; 1471 } 1472 1473 return 0; 1474 } 1475 1476 device_initcall(init_blk_tracer); 1477 1478 static int blk_trace_remove_queue(struct request_queue *q) 1479 { 1480 struct blk_trace *bt; 1481 1482 bt = xchg(&q->blk_trace, NULL); 1483 if (bt == NULL) 1484 return -EINVAL; 1485 1486 if (atomic_dec_and_test(&blk_probes_ref)) 1487 blk_unregister_tracepoints(); 1488 1489 blk_trace_free(bt); 1490 return 0; 1491 } 1492 1493 /* 1494 * Setup everything required to start tracing 1495 */ 1496 static int blk_trace_setup_queue(struct request_queue *q, 1497 struct block_device *bdev) 1498 { 1499 struct blk_trace *old_bt, *bt = NULL; 1500 int ret = -ENOMEM; 1501 1502 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1503 if (!bt) 1504 return -ENOMEM; 1505 1506 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1507 if (!bt->msg_data) 1508 goto free_bt; 1509 1510 bt->dev = bdev->bd_dev; 1511 bt->act_mask = (u16)-1; 1512 1513 blk_trace_setup_lba(bt, bdev); 1514 1515 old_bt = xchg(&q->blk_trace, bt); 1516 if (old_bt != NULL) { 1517 (void)xchg(&q->blk_trace, old_bt); 1518 ret = -EBUSY; 1519 goto free_bt; 1520 } 1521 1522 if (atomic_inc_return(&blk_probes_ref) == 1) 1523 blk_register_tracepoints(); 1524 return 0; 1525 1526 free_bt: 1527 blk_trace_free(bt); 1528 return ret; 1529 } 1530 1531 /* 1532 * sysfs interface to enable and configure tracing 1533 */ 1534 1535 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1536 struct device_attribute *attr, 1537 char *buf); 1538 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1539 struct device_attribute *attr, 1540 const char *buf, size_t count); 1541 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1542 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1543 sysfs_blk_trace_attr_show, \ 1544 sysfs_blk_trace_attr_store) 1545 1546 static BLK_TRACE_DEVICE_ATTR(enable); 1547 static BLK_TRACE_DEVICE_ATTR(act_mask); 1548 static BLK_TRACE_DEVICE_ATTR(pid); 1549 static BLK_TRACE_DEVICE_ATTR(start_lba); 1550 static BLK_TRACE_DEVICE_ATTR(end_lba); 1551 1552 static struct attribute *blk_trace_attrs[] = { 1553 &dev_attr_enable.attr, 1554 &dev_attr_act_mask.attr, 1555 &dev_attr_pid.attr, 1556 &dev_attr_start_lba.attr, 1557 &dev_attr_end_lba.attr, 1558 NULL 1559 }; 1560 1561 struct attribute_group blk_trace_attr_group = { 1562 .name = "trace", 1563 .attrs = blk_trace_attrs, 1564 }; 1565 1566 static const struct { 1567 int mask; 1568 const char *str; 1569 } mask_maps[] = { 1570 { BLK_TC_READ, "read" }, 1571 { BLK_TC_WRITE, "write" }, 1572 { BLK_TC_BARRIER, "barrier" }, 1573 { BLK_TC_SYNC, "sync" }, 1574 { BLK_TC_QUEUE, "queue" }, 1575 { BLK_TC_REQUEUE, "requeue" }, 1576 { BLK_TC_ISSUE, "issue" }, 1577 { BLK_TC_COMPLETE, "complete" }, 1578 { BLK_TC_FS, "fs" }, 1579 { BLK_TC_PC, "pc" }, 1580 { BLK_TC_AHEAD, "ahead" }, 1581 { BLK_TC_META, "meta" }, 1582 { BLK_TC_DISCARD, "discard" }, 1583 { BLK_TC_DRV_DATA, "drv_data" }, 1584 }; 1585 1586 static int blk_trace_str2mask(const char *str) 1587 { 1588 int i; 1589 int mask = 0; 1590 char *buf, *s, *token; 1591 1592 buf = kstrdup(str, GFP_KERNEL); 1593 if (buf == NULL) 1594 return -ENOMEM; 1595 s = strstrip(buf); 1596 1597 while (1) { 1598 token = strsep(&s, ","); 1599 if (token == NULL) 1600 break; 1601 1602 if (*token == '\0') 1603 continue; 1604 1605 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1606 if (strcasecmp(token, mask_maps[i].str) == 0) { 1607 mask |= mask_maps[i].mask; 1608 break; 1609 } 1610 } 1611 if (i == ARRAY_SIZE(mask_maps)) { 1612 mask = -EINVAL; 1613 break; 1614 } 1615 } 1616 kfree(buf); 1617 1618 return mask; 1619 } 1620 1621 static ssize_t blk_trace_mask2str(char *buf, int mask) 1622 { 1623 int i; 1624 char *p = buf; 1625 1626 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1627 if (mask & mask_maps[i].mask) { 1628 p += sprintf(p, "%s%s", 1629 (p == buf) ? "" : ",", mask_maps[i].str); 1630 } 1631 } 1632 *p++ = '\n'; 1633 1634 return p - buf; 1635 } 1636 1637 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1638 { 1639 if (bdev->bd_disk == NULL) 1640 return NULL; 1641 1642 return bdev_get_queue(bdev); 1643 } 1644 1645 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1646 struct device_attribute *attr, 1647 char *buf) 1648 { 1649 struct hd_struct *p = dev_to_part(dev); 1650 struct request_queue *q; 1651 struct block_device *bdev; 1652 ssize_t ret = -ENXIO; 1653 1654 bdev = bdget(part_devt(p)); 1655 if (bdev == NULL) 1656 goto out; 1657 1658 q = blk_trace_get_queue(bdev); 1659 if (q == NULL) 1660 goto out_bdput; 1661 1662 mutex_lock(&bdev->bd_mutex); 1663 1664 if (attr == &dev_attr_enable) { 1665 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1666 goto out_unlock_bdev; 1667 } 1668 1669 if (q->blk_trace == NULL) 1670 ret = sprintf(buf, "disabled\n"); 1671 else if (attr == &dev_attr_act_mask) 1672 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1673 else if (attr == &dev_attr_pid) 1674 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1675 else if (attr == &dev_attr_start_lba) 1676 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1677 else if (attr == &dev_attr_end_lba) 1678 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1679 1680 out_unlock_bdev: 1681 mutex_unlock(&bdev->bd_mutex); 1682 out_bdput: 1683 bdput(bdev); 1684 out: 1685 return ret; 1686 } 1687 1688 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1689 struct device_attribute *attr, 1690 const char *buf, size_t count) 1691 { 1692 struct block_device *bdev; 1693 struct request_queue *q; 1694 struct hd_struct *p; 1695 u64 value; 1696 ssize_t ret = -EINVAL; 1697 1698 if (count == 0) 1699 goto out; 1700 1701 if (attr == &dev_attr_act_mask) { 1702 if (sscanf(buf, "%llx", &value) != 1) { 1703 /* Assume it is a list of trace category names */ 1704 ret = blk_trace_str2mask(buf); 1705 if (ret < 0) 1706 goto out; 1707 value = ret; 1708 } 1709 } else if (sscanf(buf, "%llu", &value) != 1) 1710 goto out; 1711 1712 ret = -ENXIO; 1713 1714 p = dev_to_part(dev); 1715 bdev = bdget(part_devt(p)); 1716 if (bdev == NULL) 1717 goto out; 1718 1719 q = blk_trace_get_queue(bdev); 1720 if (q == NULL) 1721 goto out_bdput; 1722 1723 mutex_lock(&bdev->bd_mutex); 1724 1725 if (attr == &dev_attr_enable) { 1726 if (value) 1727 ret = blk_trace_setup_queue(q, bdev); 1728 else 1729 ret = blk_trace_remove_queue(q); 1730 goto out_unlock_bdev; 1731 } 1732 1733 ret = 0; 1734 if (q->blk_trace == NULL) 1735 ret = blk_trace_setup_queue(q, bdev); 1736 1737 if (ret == 0) { 1738 if (attr == &dev_attr_act_mask) 1739 q->blk_trace->act_mask = value; 1740 else if (attr == &dev_attr_pid) 1741 q->blk_trace->pid = value; 1742 else if (attr == &dev_attr_start_lba) 1743 q->blk_trace->start_lba = value; 1744 else if (attr == &dev_attr_end_lba) 1745 q->blk_trace->end_lba = value; 1746 } 1747 1748 out_unlock_bdev: 1749 mutex_unlock(&bdev->bd_mutex); 1750 out_bdput: 1751 bdput(bdev); 1752 out: 1753 return ret ? ret : count; 1754 } 1755 1756 int blk_trace_init_sysfs(struct device *dev) 1757 { 1758 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1759 } 1760 1761 void blk_trace_remove_sysfs(struct device *dev) 1762 { 1763 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1764 } 1765 1766 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1767 1768 #ifdef CONFIG_EVENT_TRACING 1769 1770 void blk_dump_cmd(char *buf, struct request *rq) 1771 { 1772 int i, end; 1773 int len = rq->cmd_len; 1774 unsigned char *cmd = rq->cmd; 1775 1776 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) { 1777 buf[0] = '\0'; 1778 return; 1779 } 1780 1781 for (end = len - 1; end >= 0; end--) 1782 if (cmd[end]) 1783 break; 1784 end++; 1785 1786 for (i = 0; i < len; i++) { 1787 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1788 if (i == end && end != len - 1) { 1789 sprintf(buf, " .."); 1790 break; 1791 } 1792 } 1793 } 1794 1795 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) 1796 { 1797 int i = 0; 1798 1799 if (rw & WRITE) 1800 rwbs[i++] = 'W'; 1801 else if (rw & REQ_DISCARD) 1802 rwbs[i++] = 'D'; 1803 else if (bytes) 1804 rwbs[i++] = 'R'; 1805 else 1806 rwbs[i++] = 'N'; 1807 1808 if (rw & REQ_RAHEAD) 1809 rwbs[i++] = 'A'; 1810 if (rw & REQ_HARDBARRIER) 1811 rwbs[i++] = 'B'; 1812 if (rw & REQ_SYNC) 1813 rwbs[i++] = 'S'; 1814 if (rw & REQ_META) 1815 rwbs[i++] = 'M'; 1816 if (rw & REQ_SECURE) 1817 rwbs[i++] = 'E'; 1818 1819 rwbs[i] = '\0'; 1820 } 1821 1822 void blk_fill_rwbs_rq(char *rwbs, struct request *rq) 1823 { 1824 int rw = rq->cmd_flags & 0x03; 1825 int bytes; 1826 1827 if (rq->cmd_flags & REQ_DISCARD) 1828 rw |= REQ_DISCARD; 1829 1830 if (rq->cmd_flags & REQ_SECURE) 1831 rw |= REQ_SECURE; 1832 1833 bytes = blk_rq_bytes(rq); 1834 1835 blk_fill_rwbs(rwbs, rw, bytes); 1836 } 1837 1838 #endif /* CONFIG_EVENT_TRACING */ 1839 1840