1 /* 2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 16 * 17 */ 18 #include <linux/kernel.h> 19 #include <linux/blkdev.h> 20 #include <linux/blktrace_api.h> 21 #include <linux/percpu.h> 22 #include <linux/init.h> 23 #include <linux/mutex.h> 24 #include <linux/slab.h> 25 #include <linux/debugfs.h> 26 #include <linux/smp_lock.h> 27 #include <linux/time.h> 28 #include <linux/uaccess.h> 29 30 #include <trace/events/block.h> 31 32 #include "trace_output.h" 33 34 #ifdef CONFIG_BLK_DEV_IO_TRACE 35 36 static unsigned int blktrace_seq __read_mostly = 1; 37 38 static struct trace_array *blk_tr; 39 static bool blk_tracer_enabled __read_mostly; 40 41 /* Select an alternative, minimalistic output than the original one */ 42 #define TRACE_BLK_OPT_CLASSIC 0x1 43 44 static struct tracer_opt blk_tracer_opts[] = { 45 /* Default disable the minimalistic output */ 46 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 47 { } 48 }; 49 50 static struct tracer_flags blk_tracer_flags = { 51 .val = 0, 52 .opts = blk_tracer_opts, 53 }; 54 55 /* Global reference count of probes */ 56 static atomic_t blk_probes_ref = ATOMIC_INIT(0); 57 58 static void blk_register_tracepoints(void); 59 static void blk_unregister_tracepoints(void); 60 61 /* 62 * Send out a notify message. 63 */ 64 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 65 const void *data, size_t len) 66 { 67 struct blk_io_trace *t; 68 struct ring_buffer_event *event = NULL; 69 struct ring_buffer *buffer = NULL; 70 int pc = 0; 71 int cpu = smp_processor_id(); 72 bool blk_tracer = blk_tracer_enabled; 73 74 if (blk_tracer) { 75 buffer = blk_tr->buffer; 76 pc = preempt_count(); 77 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 78 sizeof(*t) + len, 79 0, pc); 80 if (!event) 81 return; 82 t = ring_buffer_event_data(event); 83 goto record_it; 84 } 85 86 if (!bt->rchan) 87 return; 88 89 t = relay_reserve(bt->rchan, sizeof(*t) + len); 90 if (t) { 91 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 92 t->time = ktime_to_ns(ktime_get()); 93 record_it: 94 t->device = bt->dev; 95 t->action = action; 96 t->pid = pid; 97 t->cpu = cpu; 98 t->pdu_len = len; 99 memcpy((void *) t + sizeof(*t), data, len); 100 101 if (blk_tracer) 102 trace_buffer_unlock_commit(buffer, event, 0, pc); 103 } 104 } 105 106 /* 107 * Send out a notify for this process, if we haven't done so since a trace 108 * started 109 */ 110 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) 111 { 112 tsk->btrace_seq = blktrace_seq; 113 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm)); 114 } 115 116 static void trace_note_time(struct blk_trace *bt) 117 { 118 struct timespec now; 119 unsigned long flags; 120 u32 words[2]; 121 122 getnstimeofday(&now); 123 words[0] = now.tv_sec; 124 words[1] = now.tv_nsec; 125 126 local_irq_save(flags); 127 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); 128 local_irq_restore(flags); 129 } 130 131 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 132 { 133 int n; 134 va_list args; 135 unsigned long flags; 136 char *buf; 137 138 if (unlikely(bt->trace_state != Blktrace_running && 139 !blk_tracer_enabled)) 140 return; 141 142 local_irq_save(flags); 143 buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); 144 va_start(args, fmt); 145 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 146 va_end(args); 147 148 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); 149 local_irq_restore(flags); 150 } 151 EXPORT_SYMBOL_GPL(__trace_note_message); 152 153 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 154 pid_t pid) 155 { 156 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 157 return 1; 158 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 159 return 1; 160 if (bt->pid && pid != bt->pid) 161 return 1; 162 163 return 0; 164 } 165 166 /* 167 * Data direction bit lookup 168 */ 169 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 170 BLK_TC_ACT(BLK_TC_WRITE) }; 171 172 #define BLK_TC_HARDBARRIER BLK_TC_BARRIER 173 #define BLK_TC_RAHEAD BLK_TC_AHEAD 174 175 /* The ilog2() calls fall out because they're constant */ 176 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \ 177 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name)) 178 179 /* 180 * The worker for the various blk_add_trace*() types. Fills out a 181 * blk_io_trace structure and places it in a per-cpu subbuffer. 182 */ 183 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 184 int rw, u32 what, int error, int pdu_len, void *pdu_data) 185 { 186 struct task_struct *tsk = current; 187 struct ring_buffer_event *event = NULL; 188 struct ring_buffer *buffer = NULL; 189 struct blk_io_trace *t; 190 unsigned long flags = 0; 191 unsigned long *sequence; 192 pid_t pid; 193 int cpu, pc = 0; 194 bool blk_tracer = blk_tracer_enabled; 195 196 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 197 return; 198 199 what |= ddir_act[rw & WRITE]; 200 what |= MASK_TC_BIT(rw, HARDBARRIER); 201 what |= MASK_TC_BIT(rw, SYNC); 202 what |= MASK_TC_BIT(rw, RAHEAD); 203 what |= MASK_TC_BIT(rw, META); 204 what |= MASK_TC_BIT(rw, DISCARD); 205 206 pid = tsk->pid; 207 if (act_log_check(bt, what, sector, pid)) 208 return; 209 cpu = raw_smp_processor_id(); 210 211 if (blk_tracer) { 212 tracing_record_cmdline(current); 213 214 buffer = blk_tr->buffer; 215 pc = preempt_count(); 216 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 217 sizeof(*t) + pdu_len, 218 0, pc); 219 if (!event) 220 return; 221 t = ring_buffer_event_data(event); 222 goto record_it; 223 } 224 225 /* 226 * A word about the locking here - we disable interrupts to reserve 227 * some space in the relay per-cpu buffer, to prevent an irq 228 * from coming in and stepping on our toes. 229 */ 230 local_irq_save(flags); 231 232 if (unlikely(tsk->btrace_seq != blktrace_seq)) 233 trace_note_tsk(bt, tsk); 234 235 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 236 if (t) { 237 sequence = per_cpu_ptr(bt->sequence, cpu); 238 239 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 240 t->sequence = ++(*sequence); 241 t->time = ktime_to_ns(ktime_get()); 242 record_it: 243 /* 244 * These two are not needed in ftrace as they are in the 245 * generic trace_entry, filled by tracing_generic_entry_update, 246 * but for the trace_event->bin() synthesizer benefit we do it 247 * here too. 248 */ 249 t->cpu = cpu; 250 t->pid = pid; 251 252 t->sector = sector; 253 t->bytes = bytes; 254 t->action = what; 255 t->device = bt->dev; 256 t->error = error; 257 t->pdu_len = pdu_len; 258 259 if (pdu_len) 260 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 261 262 if (blk_tracer) { 263 trace_buffer_unlock_commit(buffer, event, 0, pc); 264 return; 265 } 266 } 267 268 local_irq_restore(flags); 269 } 270 271 static struct dentry *blk_tree_root; 272 static DEFINE_MUTEX(blk_tree_mutex); 273 274 static void blk_trace_free(struct blk_trace *bt) 275 { 276 debugfs_remove(bt->msg_file); 277 debugfs_remove(bt->dropped_file); 278 relay_close(bt->rchan); 279 debugfs_remove(bt->dir); 280 free_percpu(bt->sequence); 281 free_percpu(bt->msg_data); 282 kfree(bt); 283 } 284 285 static void blk_trace_cleanup(struct blk_trace *bt) 286 { 287 blk_trace_free(bt); 288 if (atomic_dec_and_test(&blk_probes_ref)) 289 blk_unregister_tracepoints(); 290 } 291 292 int blk_trace_remove(struct request_queue *q) 293 { 294 struct blk_trace *bt; 295 296 bt = xchg(&q->blk_trace, NULL); 297 if (!bt) 298 return -EINVAL; 299 300 if (bt->trace_state != Blktrace_running) 301 blk_trace_cleanup(bt); 302 303 return 0; 304 } 305 EXPORT_SYMBOL_GPL(blk_trace_remove); 306 307 static int blk_dropped_open(struct inode *inode, struct file *filp) 308 { 309 filp->private_data = inode->i_private; 310 311 return 0; 312 } 313 314 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 315 size_t count, loff_t *ppos) 316 { 317 struct blk_trace *bt = filp->private_data; 318 char buf[16]; 319 320 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 321 322 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 323 } 324 325 static const struct file_operations blk_dropped_fops = { 326 .owner = THIS_MODULE, 327 .open = blk_dropped_open, 328 .read = blk_dropped_read, 329 }; 330 331 static int blk_msg_open(struct inode *inode, struct file *filp) 332 { 333 filp->private_data = inode->i_private; 334 335 return 0; 336 } 337 338 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 339 size_t count, loff_t *ppos) 340 { 341 char *msg; 342 struct blk_trace *bt; 343 344 if (count >= BLK_TN_MAX_MSG) 345 return -EINVAL; 346 347 msg = kmalloc(count + 1, GFP_KERNEL); 348 if (msg == NULL) 349 return -ENOMEM; 350 351 if (copy_from_user(msg, buffer, count)) { 352 kfree(msg); 353 return -EFAULT; 354 } 355 356 msg[count] = '\0'; 357 bt = filp->private_data; 358 __trace_note_message(bt, "%s", msg); 359 kfree(msg); 360 361 return count; 362 } 363 364 static const struct file_operations blk_msg_fops = { 365 .owner = THIS_MODULE, 366 .open = blk_msg_open, 367 .write = blk_msg_write, 368 }; 369 370 /* 371 * Keep track of how many times we encountered a full subbuffer, to aid 372 * the user space app in telling how many lost events there were. 373 */ 374 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 375 void *prev_subbuf, size_t prev_padding) 376 { 377 struct blk_trace *bt; 378 379 if (!relay_buf_full(buf)) 380 return 1; 381 382 bt = buf->chan->private_data; 383 atomic_inc(&bt->dropped); 384 return 0; 385 } 386 387 static int blk_remove_buf_file_callback(struct dentry *dentry) 388 { 389 debugfs_remove(dentry); 390 391 return 0; 392 } 393 394 static struct dentry *blk_create_buf_file_callback(const char *filename, 395 struct dentry *parent, 396 int mode, 397 struct rchan_buf *buf, 398 int *is_global) 399 { 400 return debugfs_create_file(filename, mode, parent, buf, 401 &relay_file_operations); 402 } 403 404 static struct rchan_callbacks blk_relay_callbacks = { 405 .subbuf_start = blk_subbuf_start_callback, 406 .create_buf_file = blk_create_buf_file_callback, 407 .remove_buf_file = blk_remove_buf_file_callback, 408 }; 409 410 static void blk_trace_setup_lba(struct blk_trace *bt, 411 struct block_device *bdev) 412 { 413 struct hd_struct *part = NULL; 414 415 if (bdev) 416 part = bdev->bd_part; 417 418 if (part) { 419 bt->start_lba = part->start_sect; 420 bt->end_lba = part->start_sect + part->nr_sects; 421 } else { 422 bt->start_lba = 0; 423 bt->end_lba = -1ULL; 424 } 425 } 426 427 /* 428 * Setup everything required to start tracing 429 */ 430 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 431 struct block_device *bdev, 432 struct blk_user_trace_setup *buts) 433 { 434 struct blk_trace *old_bt, *bt = NULL; 435 struct dentry *dir = NULL; 436 int ret, i; 437 438 if (!buts->buf_size || !buts->buf_nr) 439 return -EINVAL; 440 441 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 442 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 443 444 /* 445 * some device names have larger paths - convert the slashes 446 * to underscores for this to work as expected 447 */ 448 for (i = 0; i < strlen(buts->name); i++) 449 if (buts->name[i] == '/') 450 buts->name[i] = '_'; 451 452 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 453 if (!bt) 454 return -ENOMEM; 455 456 ret = -ENOMEM; 457 bt->sequence = alloc_percpu(unsigned long); 458 if (!bt->sequence) 459 goto err; 460 461 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 462 if (!bt->msg_data) 463 goto err; 464 465 ret = -ENOENT; 466 467 mutex_lock(&blk_tree_mutex); 468 if (!blk_tree_root) { 469 blk_tree_root = debugfs_create_dir("block", NULL); 470 if (!blk_tree_root) { 471 mutex_unlock(&blk_tree_mutex); 472 goto err; 473 } 474 } 475 mutex_unlock(&blk_tree_mutex); 476 477 dir = debugfs_create_dir(buts->name, blk_tree_root); 478 479 if (!dir) 480 goto err; 481 482 bt->dir = dir; 483 bt->dev = dev; 484 atomic_set(&bt->dropped, 0); 485 486 ret = -EIO; 487 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 488 &blk_dropped_fops); 489 if (!bt->dropped_file) 490 goto err; 491 492 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 493 if (!bt->msg_file) 494 goto err; 495 496 bt->rchan = relay_open("trace", dir, buts->buf_size, 497 buts->buf_nr, &blk_relay_callbacks, bt); 498 if (!bt->rchan) 499 goto err; 500 501 bt->act_mask = buts->act_mask; 502 if (!bt->act_mask) 503 bt->act_mask = (u16) -1; 504 505 blk_trace_setup_lba(bt, bdev); 506 507 /* overwrite with user settings */ 508 if (buts->start_lba) 509 bt->start_lba = buts->start_lba; 510 if (buts->end_lba) 511 bt->end_lba = buts->end_lba; 512 513 bt->pid = buts->pid; 514 bt->trace_state = Blktrace_setup; 515 516 ret = -EBUSY; 517 old_bt = xchg(&q->blk_trace, bt); 518 if (old_bt) { 519 (void) xchg(&q->blk_trace, old_bt); 520 goto err; 521 } 522 523 if (atomic_inc_return(&blk_probes_ref) == 1) 524 blk_register_tracepoints(); 525 526 return 0; 527 err: 528 blk_trace_free(bt); 529 return ret; 530 } 531 532 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 533 struct block_device *bdev, 534 char __user *arg) 535 { 536 struct blk_user_trace_setup buts; 537 int ret; 538 539 ret = copy_from_user(&buts, arg, sizeof(buts)); 540 if (ret) 541 return -EFAULT; 542 543 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 544 if (ret) 545 return ret; 546 547 if (copy_to_user(arg, &buts, sizeof(buts))) { 548 blk_trace_remove(q); 549 return -EFAULT; 550 } 551 return 0; 552 } 553 EXPORT_SYMBOL_GPL(blk_trace_setup); 554 555 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 556 static int compat_blk_trace_setup(struct request_queue *q, char *name, 557 dev_t dev, struct block_device *bdev, 558 char __user *arg) 559 { 560 struct blk_user_trace_setup buts; 561 struct compat_blk_user_trace_setup cbuts; 562 int ret; 563 564 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 565 return -EFAULT; 566 567 buts = (struct blk_user_trace_setup) { 568 .act_mask = cbuts.act_mask, 569 .buf_size = cbuts.buf_size, 570 .buf_nr = cbuts.buf_nr, 571 .start_lba = cbuts.start_lba, 572 .end_lba = cbuts.end_lba, 573 .pid = cbuts.pid, 574 }; 575 memcpy(&buts.name, &cbuts.name, 32); 576 577 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 578 if (ret) 579 return ret; 580 581 if (copy_to_user(arg, &buts.name, 32)) { 582 blk_trace_remove(q); 583 return -EFAULT; 584 } 585 586 return 0; 587 } 588 #endif 589 590 int blk_trace_startstop(struct request_queue *q, int start) 591 { 592 int ret; 593 struct blk_trace *bt = q->blk_trace; 594 595 if (bt == NULL) 596 return -EINVAL; 597 598 /* 599 * For starting a trace, we can transition from a setup or stopped 600 * trace. For stopping a trace, the state must be running 601 */ 602 ret = -EINVAL; 603 if (start) { 604 if (bt->trace_state == Blktrace_setup || 605 bt->trace_state == Blktrace_stopped) { 606 blktrace_seq++; 607 smp_mb(); 608 bt->trace_state = Blktrace_running; 609 610 trace_note_time(bt); 611 ret = 0; 612 } 613 } else { 614 if (bt->trace_state == Blktrace_running) { 615 bt->trace_state = Blktrace_stopped; 616 relay_flush(bt->rchan); 617 ret = 0; 618 } 619 } 620 621 return ret; 622 } 623 EXPORT_SYMBOL_GPL(blk_trace_startstop); 624 625 /** 626 * blk_trace_ioctl: - handle the ioctls associated with tracing 627 * @bdev: the block device 628 * @cmd: the ioctl cmd 629 * @arg: the argument data, if any 630 * 631 **/ 632 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 633 { 634 struct request_queue *q; 635 int ret, start = 0; 636 char b[BDEVNAME_SIZE]; 637 638 q = bdev_get_queue(bdev); 639 if (!q) 640 return -ENXIO; 641 642 lock_kernel(); 643 mutex_lock(&bdev->bd_mutex); 644 645 switch (cmd) { 646 case BLKTRACESETUP: 647 bdevname(bdev, b); 648 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 649 break; 650 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 651 case BLKTRACESETUP32: 652 bdevname(bdev, b); 653 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 654 break; 655 #endif 656 case BLKTRACESTART: 657 start = 1; 658 case BLKTRACESTOP: 659 ret = blk_trace_startstop(q, start); 660 break; 661 case BLKTRACETEARDOWN: 662 ret = blk_trace_remove(q); 663 break; 664 default: 665 ret = -ENOTTY; 666 break; 667 } 668 669 mutex_unlock(&bdev->bd_mutex); 670 unlock_kernel(); 671 return ret; 672 } 673 674 /** 675 * blk_trace_shutdown: - stop and cleanup trace structures 676 * @q: the request queue associated with the device 677 * 678 **/ 679 void blk_trace_shutdown(struct request_queue *q) 680 { 681 if (q->blk_trace) { 682 blk_trace_startstop(q, 0); 683 blk_trace_remove(q); 684 } 685 } 686 687 /* 688 * blktrace probes 689 */ 690 691 /** 692 * blk_add_trace_rq - Add a trace for a request oriented action 693 * @q: queue the io is for 694 * @rq: the source request 695 * @what: the action 696 * 697 * Description: 698 * Records an action against a request. Will log the bio offset + size. 699 * 700 **/ 701 static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 702 u32 what) 703 { 704 struct blk_trace *bt = q->blk_trace; 705 int rw = rq->cmd_flags & 0x03; 706 707 if (likely(!bt)) 708 return; 709 710 if (rq->cmd_flags & REQ_DISCARD) 711 rw |= REQ_DISCARD; 712 713 if (rq->cmd_flags & REQ_SECURE) 714 rw |= REQ_SECURE; 715 716 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { 717 what |= BLK_TC_ACT(BLK_TC_PC); 718 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw, 719 what, rq->errors, rq->cmd_len, rq->cmd); 720 } else { 721 what |= BLK_TC_ACT(BLK_TC_FS); 722 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw, 723 what, rq->errors, 0, NULL); 724 } 725 } 726 727 static void blk_add_trace_rq_abort(void *ignore, 728 struct request_queue *q, struct request *rq) 729 { 730 blk_add_trace_rq(q, rq, BLK_TA_ABORT); 731 } 732 733 static void blk_add_trace_rq_insert(void *ignore, 734 struct request_queue *q, struct request *rq) 735 { 736 blk_add_trace_rq(q, rq, BLK_TA_INSERT); 737 } 738 739 static void blk_add_trace_rq_issue(void *ignore, 740 struct request_queue *q, struct request *rq) 741 { 742 blk_add_trace_rq(q, rq, BLK_TA_ISSUE); 743 } 744 745 static void blk_add_trace_rq_requeue(void *ignore, 746 struct request_queue *q, 747 struct request *rq) 748 { 749 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); 750 } 751 752 static void blk_add_trace_rq_complete(void *ignore, 753 struct request_queue *q, 754 struct request *rq) 755 { 756 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE); 757 } 758 759 /** 760 * blk_add_trace_bio - Add a trace for a bio oriented action 761 * @q: queue the io is for 762 * @bio: the source bio 763 * @what: the action 764 * 765 * Description: 766 * Records an action against a bio. Will log the bio offset + size. 767 * 768 **/ 769 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 770 u32 what) 771 { 772 struct blk_trace *bt = q->blk_trace; 773 774 if (likely(!bt)) 775 return; 776 777 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, 778 !bio_flagged(bio, BIO_UPTODATE), 0, NULL); 779 } 780 781 static void blk_add_trace_bio_bounce(void *ignore, 782 struct request_queue *q, struct bio *bio) 783 { 784 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE); 785 } 786 787 static void blk_add_trace_bio_complete(void *ignore, 788 struct request_queue *q, struct bio *bio) 789 { 790 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE); 791 } 792 793 static void blk_add_trace_bio_backmerge(void *ignore, 794 struct request_queue *q, 795 struct bio *bio) 796 { 797 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE); 798 } 799 800 static void blk_add_trace_bio_frontmerge(void *ignore, 801 struct request_queue *q, 802 struct bio *bio) 803 { 804 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE); 805 } 806 807 static void blk_add_trace_bio_queue(void *ignore, 808 struct request_queue *q, struct bio *bio) 809 { 810 blk_add_trace_bio(q, bio, BLK_TA_QUEUE); 811 } 812 813 static void blk_add_trace_getrq(void *ignore, 814 struct request_queue *q, 815 struct bio *bio, int rw) 816 { 817 if (bio) 818 blk_add_trace_bio(q, bio, BLK_TA_GETRQ); 819 else { 820 struct blk_trace *bt = q->blk_trace; 821 822 if (bt) 823 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); 824 } 825 } 826 827 828 static void blk_add_trace_sleeprq(void *ignore, 829 struct request_queue *q, 830 struct bio *bio, int rw) 831 { 832 if (bio) 833 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ); 834 else { 835 struct blk_trace *bt = q->blk_trace; 836 837 if (bt) 838 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 839 0, 0, NULL); 840 } 841 } 842 843 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 844 { 845 struct blk_trace *bt = q->blk_trace; 846 847 if (bt) 848 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 849 } 850 851 static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q) 852 { 853 struct blk_trace *bt = q->blk_trace; 854 855 if (bt) { 856 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 857 __be64 rpdu = cpu_to_be64(pdu); 858 859 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0, 860 sizeof(rpdu), &rpdu); 861 } 862 } 863 864 static void blk_add_trace_unplug_timer(void *ignore, struct request_queue *q) 865 { 866 struct blk_trace *bt = q->blk_trace; 867 868 if (bt) { 869 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; 870 __be64 rpdu = cpu_to_be64(pdu); 871 872 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0, 873 sizeof(rpdu), &rpdu); 874 } 875 } 876 877 static void blk_add_trace_split(void *ignore, 878 struct request_queue *q, struct bio *bio, 879 unsigned int pdu) 880 { 881 struct blk_trace *bt = q->blk_trace; 882 883 if (bt) { 884 __be64 rpdu = cpu_to_be64(pdu); 885 886 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 887 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE), 888 sizeof(rpdu), &rpdu); 889 } 890 } 891 892 /** 893 * blk_add_trace_remap - Add a trace for a remap operation 894 * @ignore: trace callback data parameter (not used) 895 * @q: queue the io is for 896 * @bio: the source bio 897 * @dev: target device 898 * @from: source sector 899 * 900 * Description: 901 * Device mapper or raid target sometimes need to split a bio because 902 * it spans a stripe (or similar). Add a trace for that action. 903 * 904 **/ 905 static void blk_add_trace_remap(void *ignore, 906 struct request_queue *q, struct bio *bio, 907 dev_t dev, sector_t from) 908 { 909 struct blk_trace *bt = q->blk_trace; 910 struct blk_io_trace_remap r; 911 912 if (likely(!bt)) 913 return; 914 915 r.device_from = cpu_to_be32(dev); 916 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 917 r.sector_from = cpu_to_be64(from); 918 919 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, 920 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), 921 sizeof(r), &r); 922 } 923 924 /** 925 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 926 * @ignore: trace callback data parameter (not used) 927 * @q: queue the io is for 928 * @rq: the source request 929 * @dev: target device 930 * @from: source sector 931 * 932 * Description: 933 * Device mapper remaps request to other devices. 934 * Add a trace for that action. 935 * 936 **/ 937 static void blk_add_trace_rq_remap(void *ignore, 938 struct request_queue *q, 939 struct request *rq, dev_t dev, 940 sector_t from) 941 { 942 struct blk_trace *bt = q->blk_trace; 943 struct blk_io_trace_remap r; 944 945 if (likely(!bt)) 946 return; 947 948 r.device_from = cpu_to_be32(dev); 949 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 950 r.sector_from = cpu_to_be64(from); 951 952 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 953 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors, 954 sizeof(r), &r); 955 } 956 957 /** 958 * blk_add_driver_data - Add binary message with driver-specific data 959 * @q: queue the io is for 960 * @rq: io request 961 * @data: driver-specific data 962 * @len: length of driver-specific data 963 * 964 * Description: 965 * Some drivers might want to write driver-specific data per request. 966 * 967 **/ 968 void blk_add_driver_data(struct request_queue *q, 969 struct request *rq, 970 void *data, size_t len) 971 { 972 struct blk_trace *bt = q->blk_trace; 973 974 if (likely(!bt)) 975 return; 976 977 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) 978 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 979 BLK_TA_DRV_DATA, rq->errors, len, data); 980 else 981 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 982 BLK_TA_DRV_DATA, rq->errors, len, data); 983 } 984 EXPORT_SYMBOL_GPL(blk_add_driver_data); 985 986 static void blk_register_tracepoints(void) 987 { 988 int ret; 989 990 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 991 WARN_ON(ret); 992 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 993 WARN_ON(ret); 994 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 995 WARN_ON(ret); 996 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 997 WARN_ON(ret); 998 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 999 WARN_ON(ret); 1000 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1001 WARN_ON(ret); 1002 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1003 WARN_ON(ret); 1004 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1005 WARN_ON(ret); 1006 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1007 WARN_ON(ret); 1008 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1009 WARN_ON(ret); 1010 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 1011 WARN_ON(ret); 1012 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1013 WARN_ON(ret); 1014 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 1015 WARN_ON(ret); 1016 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL); 1017 WARN_ON(ret); 1018 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, 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_remap(blk_add_trace_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_remap(blk_add_trace_remap, NULL); 1032 unregister_trace_block_split(blk_add_trace_split, NULL); 1033 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); 1034 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL); 1035 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1036 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1037 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1038 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1039 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1040 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1041 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1042 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1043 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1044 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1045 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1046 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1047 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 1048 1049 tracepoint_synchronize_unregister(); 1050 } 1051 1052 /* 1053 * struct blk_io_tracer formatting routines 1054 */ 1055 1056 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1057 { 1058 int i = 0; 1059 int tc = t->action >> BLK_TC_SHIFT; 1060 1061 if (t->action == BLK_TN_MESSAGE) { 1062 rwbs[i++] = 'N'; 1063 goto out; 1064 } 1065 1066 if (tc & BLK_TC_DISCARD) 1067 rwbs[i++] = 'D'; 1068 else if (tc & BLK_TC_WRITE) 1069 rwbs[i++] = 'W'; 1070 else if (t->bytes) 1071 rwbs[i++] = 'R'; 1072 else 1073 rwbs[i++] = 'N'; 1074 1075 if (tc & BLK_TC_AHEAD) 1076 rwbs[i++] = 'A'; 1077 if (tc & BLK_TC_BARRIER) 1078 rwbs[i++] = 'B'; 1079 if (tc & BLK_TC_SYNC) 1080 rwbs[i++] = 'S'; 1081 if (tc & BLK_TC_META) 1082 rwbs[i++] = 'M'; 1083 out: 1084 rwbs[i] = '\0'; 1085 } 1086 1087 static inline 1088 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1089 { 1090 return (const struct blk_io_trace *)ent; 1091 } 1092 1093 static inline const void *pdu_start(const struct trace_entry *ent) 1094 { 1095 return te_blk_io_trace(ent) + 1; 1096 } 1097 1098 static inline u32 t_action(const struct trace_entry *ent) 1099 { 1100 return te_blk_io_trace(ent)->action; 1101 } 1102 1103 static inline u32 t_bytes(const struct trace_entry *ent) 1104 { 1105 return te_blk_io_trace(ent)->bytes; 1106 } 1107 1108 static inline u32 t_sec(const struct trace_entry *ent) 1109 { 1110 return te_blk_io_trace(ent)->bytes >> 9; 1111 } 1112 1113 static inline unsigned long long t_sector(const struct trace_entry *ent) 1114 { 1115 return te_blk_io_trace(ent)->sector; 1116 } 1117 1118 static inline __u16 t_error(const struct trace_entry *ent) 1119 { 1120 return te_blk_io_trace(ent)->error; 1121 } 1122 1123 static __u64 get_pdu_int(const struct trace_entry *ent) 1124 { 1125 const __u64 *val = pdu_start(ent); 1126 return be64_to_cpu(*val); 1127 } 1128 1129 static void get_pdu_remap(const struct trace_entry *ent, 1130 struct blk_io_trace_remap *r) 1131 { 1132 const struct blk_io_trace_remap *__r = pdu_start(ent); 1133 __u64 sector_from = __r->sector_from; 1134 1135 r->device_from = be32_to_cpu(__r->device_from); 1136 r->device_to = be32_to_cpu(__r->device_to); 1137 r->sector_from = be64_to_cpu(sector_from); 1138 } 1139 1140 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1141 1142 static int blk_log_action_classic(struct trace_iterator *iter, const char *act) 1143 { 1144 char rwbs[6]; 1145 unsigned long long ts = iter->ts; 1146 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1147 unsigned secs = (unsigned long)ts; 1148 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1149 1150 fill_rwbs(rwbs, t); 1151 1152 return trace_seq_printf(&iter->seq, 1153 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1154 MAJOR(t->device), MINOR(t->device), iter->cpu, 1155 secs, nsec_rem, iter->ent->pid, act, rwbs); 1156 } 1157 1158 static int blk_log_action(struct trace_iterator *iter, const char *act) 1159 { 1160 char rwbs[6]; 1161 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1162 1163 fill_rwbs(rwbs, t); 1164 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1165 MAJOR(t->device), MINOR(t->device), act, rwbs); 1166 } 1167 1168 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1169 { 1170 const unsigned char *pdu_buf; 1171 int pdu_len; 1172 int i, end, ret; 1173 1174 pdu_buf = pdu_start(ent); 1175 pdu_len = te_blk_io_trace(ent)->pdu_len; 1176 1177 if (!pdu_len) 1178 return 1; 1179 1180 /* find the last zero that needs to be printed */ 1181 for (end = pdu_len - 1; end >= 0; end--) 1182 if (pdu_buf[end]) 1183 break; 1184 end++; 1185 1186 if (!trace_seq_putc(s, '(')) 1187 return 0; 1188 1189 for (i = 0; i < pdu_len; i++) { 1190 1191 ret = trace_seq_printf(s, "%s%02x", 1192 i == 0 ? "" : " ", pdu_buf[i]); 1193 if (!ret) 1194 return ret; 1195 1196 /* 1197 * stop when the rest is just zeroes and indicate so 1198 * with a ".." appended 1199 */ 1200 if (i == end && end != pdu_len - 1) 1201 return trace_seq_puts(s, " ..) "); 1202 } 1203 1204 return trace_seq_puts(s, ") "); 1205 } 1206 1207 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1208 { 1209 char cmd[TASK_COMM_LEN]; 1210 1211 trace_find_cmdline(ent->pid, cmd); 1212 1213 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1214 int ret; 1215 1216 ret = trace_seq_printf(s, "%u ", t_bytes(ent)); 1217 if (!ret) 1218 return 0; 1219 ret = blk_log_dump_pdu(s, ent); 1220 if (!ret) 1221 return 0; 1222 return trace_seq_printf(s, "[%s]\n", cmd); 1223 } else { 1224 if (t_sec(ent)) 1225 return trace_seq_printf(s, "%llu + %u [%s]\n", 1226 t_sector(ent), t_sec(ent), cmd); 1227 return trace_seq_printf(s, "[%s]\n", cmd); 1228 } 1229 } 1230 1231 static int blk_log_with_error(struct trace_seq *s, 1232 const struct trace_entry *ent) 1233 { 1234 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1235 int ret; 1236 1237 ret = blk_log_dump_pdu(s, ent); 1238 if (ret) 1239 return trace_seq_printf(s, "[%d]\n", t_error(ent)); 1240 return 0; 1241 } else { 1242 if (t_sec(ent)) 1243 return trace_seq_printf(s, "%llu + %u [%d]\n", 1244 t_sector(ent), 1245 t_sec(ent), t_error(ent)); 1246 return trace_seq_printf(s, "%llu [%d]\n", 1247 t_sector(ent), t_error(ent)); 1248 } 1249 } 1250 1251 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1252 { 1253 struct blk_io_trace_remap r = { .device_from = 0, }; 1254 1255 get_pdu_remap(ent, &r); 1256 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1257 t_sector(ent), t_sec(ent), 1258 MAJOR(r.device_from), MINOR(r.device_from), 1259 (unsigned long long)r.sector_from); 1260 } 1261 1262 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1263 { 1264 char cmd[TASK_COMM_LEN]; 1265 1266 trace_find_cmdline(ent->pid, cmd); 1267 1268 return trace_seq_printf(s, "[%s]\n", cmd); 1269 } 1270 1271 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1272 { 1273 char cmd[TASK_COMM_LEN]; 1274 1275 trace_find_cmdline(ent->pid, cmd); 1276 1277 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1278 } 1279 1280 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1281 { 1282 char cmd[TASK_COMM_LEN]; 1283 1284 trace_find_cmdline(ent->pid, cmd); 1285 1286 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1287 get_pdu_int(ent), cmd); 1288 } 1289 1290 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1291 { 1292 int ret; 1293 const struct blk_io_trace *t = te_blk_io_trace(ent); 1294 1295 ret = trace_seq_putmem(s, t + 1, t->pdu_len); 1296 if (ret) 1297 return trace_seq_putc(s, '\n'); 1298 return ret; 1299 } 1300 1301 /* 1302 * struct tracer operations 1303 */ 1304 1305 static void blk_tracer_print_header(struct seq_file *m) 1306 { 1307 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1308 return; 1309 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1310 "# | | | | | |\n"); 1311 } 1312 1313 static void blk_tracer_start(struct trace_array *tr) 1314 { 1315 blk_tracer_enabled = true; 1316 } 1317 1318 static int blk_tracer_init(struct trace_array *tr) 1319 { 1320 blk_tr = tr; 1321 blk_tracer_start(tr); 1322 return 0; 1323 } 1324 1325 static void blk_tracer_stop(struct trace_array *tr) 1326 { 1327 blk_tracer_enabled = false; 1328 } 1329 1330 static void blk_tracer_reset(struct trace_array *tr) 1331 { 1332 blk_tracer_stop(tr); 1333 } 1334 1335 static const struct { 1336 const char *act[2]; 1337 int (*print)(struct trace_seq *s, const struct trace_entry *ent); 1338 } what2act[] = { 1339 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1340 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1341 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1342 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1343 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1344 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1345 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1346 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1347 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1348 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1349 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1350 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1351 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1352 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1353 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1354 }; 1355 1356 static enum print_line_t print_one_line(struct trace_iterator *iter, 1357 bool classic) 1358 { 1359 struct trace_seq *s = &iter->seq; 1360 const struct blk_io_trace *t; 1361 u16 what; 1362 int ret; 1363 bool long_act; 1364 blk_log_action_t *log_action; 1365 1366 t = te_blk_io_trace(iter->ent); 1367 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1368 long_act = !!(trace_flags & TRACE_ITER_VERBOSE); 1369 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1370 1371 if (t->action == BLK_TN_MESSAGE) { 1372 ret = log_action(iter, long_act ? "message" : "m"); 1373 if (ret) 1374 ret = blk_log_msg(s, iter->ent); 1375 goto out; 1376 } 1377 1378 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1379 ret = trace_seq_printf(s, "Unknown action %x\n", what); 1380 else { 1381 ret = log_action(iter, what2act[what].act[long_act]); 1382 if (ret) 1383 ret = what2act[what].print(s, iter->ent); 1384 } 1385 out: 1386 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1387 } 1388 1389 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1390 int flags, struct trace_event *event) 1391 { 1392 return print_one_line(iter, false); 1393 } 1394 1395 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1396 { 1397 struct trace_seq *s = &iter->seq; 1398 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1399 const int offset = offsetof(struct blk_io_trace, sector); 1400 struct blk_io_trace old = { 1401 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1402 .time = iter->ts, 1403 }; 1404 1405 if (!trace_seq_putmem(s, &old, offset)) 1406 return 0; 1407 return trace_seq_putmem(s, &t->sector, 1408 sizeof(old) - offset + t->pdu_len); 1409 } 1410 1411 static enum print_line_t 1412 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1413 struct trace_event *event) 1414 { 1415 return blk_trace_synthesize_old_trace(iter) ? 1416 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; 1417 } 1418 1419 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1420 { 1421 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1422 return TRACE_TYPE_UNHANDLED; 1423 1424 return print_one_line(iter, true); 1425 } 1426 1427 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set) 1428 { 1429 /* don't output context-info for blk_classic output */ 1430 if (bit == TRACE_BLK_OPT_CLASSIC) { 1431 if (set) 1432 trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1433 else 1434 trace_flags |= TRACE_ITER_CONTEXT_INFO; 1435 } 1436 return 0; 1437 } 1438 1439 static struct tracer blk_tracer __read_mostly = { 1440 .name = "blk", 1441 .init = blk_tracer_init, 1442 .reset = blk_tracer_reset, 1443 .start = blk_tracer_start, 1444 .stop = blk_tracer_stop, 1445 .print_header = blk_tracer_print_header, 1446 .print_line = blk_tracer_print_line, 1447 .flags = &blk_tracer_flags, 1448 .set_flag = blk_tracer_set_flag, 1449 }; 1450 1451 static struct trace_event_functions trace_blk_event_funcs = { 1452 .trace = blk_trace_event_print, 1453 .binary = blk_trace_event_print_binary, 1454 }; 1455 1456 static struct trace_event trace_blk_event = { 1457 .type = TRACE_BLK, 1458 .funcs = &trace_blk_event_funcs, 1459 }; 1460 1461 static int __init init_blk_tracer(void) 1462 { 1463 if (!register_ftrace_event(&trace_blk_event)) { 1464 pr_warning("Warning: could not register block events\n"); 1465 return 1; 1466 } 1467 1468 if (register_tracer(&blk_tracer) != 0) { 1469 pr_warning("Warning: could not register the block tracer\n"); 1470 unregister_ftrace_event(&trace_blk_event); 1471 return 1; 1472 } 1473 1474 return 0; 1475 } 1476 1477 device_initcall(init_blk_tracer); 1478 1479 static int blk_trace_remove_queue(struct request_queue *q) 1480 { 1481 struct blk_trace *bt; 1482 1483 bt = xchg(&q->blk_trace, NULL); 1484 if (bt == NULL) 1485 return -EINVAL; 1486 1487 if (atomic_dec_and_test(&blk_probes_ref)) 1488 blk_unregister_tracepoints(); 1489 1490 blk_trace_free(bt); 1491 return 0; 1492 } 1493 1494 /* 1495 * Setup everything required to start tracing 1496 */ 1497 static int blk_trace_setup_queue(struct request_queue *q, 1498 struct block_device *bdev) 1499 { 1500 struct blk_trace *old_bt, *bt = NULL; 1501 int ret = -ENOMEM; 1502 1503 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1504 if (!bt) 1505 return -ENOMEM; 1506 1507 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1508 if (!bt->msg_data) 1509 goto free_bt; 1510 1511 bt->dev = bdev->bd_dev; 1512 bt->act_mask = (u16)-1; 1513 1514 blk_trace_setup_lba(bt, bdev); 1515 1516 old_bt = xchg(&q->blk_trace, bt); 1517 if (old_bt != NULL) { 1518 (void)xchg(&q->blk_trace, old_bt); 1519 ret = -EBUSY; 1520 goto free_bt; 1521 } 1522 1523 if (atomic_inc_return(&blk_probes_ref) == 1) 1524 blk_register_tracepoints(); 1525 return 0; 1526 1527 free_bt: 1528 blk_trace_free(bt); 1529 return ret; 1530 } 1531 1532 /* 1533 * sysfs interface to enable and configure tracing 1534 */ 1535 1536 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1537 struct device_attribute *attr, 1538 char *buf); 1539 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1540 struct device_attribute *attr, 1541 const char *buf, size_t count); 1542 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1543 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1544 sysfs_blk_trace_attr_show, \ 1545 sysfs_blk_trace_attr_store) 1546 1547 static BLK_TRACE_DEVICE_ATTR(enable); 1548 static BLK_TRACE_DEVICE_ATTR(act_mask); 1549 static BLK_TRACE_DEVICE_ATTR(pid); 1550 static BLK_TRACE_DEVICE_ATTR(start_lba); 1551 static BLK_TRACE_DEVICE_ATTR(end_lba); 1552 1553 static struct attribute *blk_trace_attrs[] = { 1554 &dev_attr_enable.attr, 1555 &dev_attr_act_mask.attr, 1556 &dev_attr_pid.attr, 1557 &dev_attr_start_lba.attr, 1558 &dev_attr_end_lba.attr, 1559 NULL 1560 }; 1561 1562 struct attribute_group blk_trace_attr_group = { 1563 .name = "trace", 1564 .attrs = blk_trace_attrs, 1565 }; 1566 1567 static const struct { 1568 int mask; 1569 const char *str; 1570 } mask_maps[] = { 1571 { BLK_TC_READ, "read" }, 1572 { BLK_TC_WRITE, "write" }, 1573 { BLK_TC_BARRIER, "barrier" }, 1574 { BLK_TC_SYNC, "sync" }, 1575 { BLK_TC_QUEUE, "queue" }, 1576 { BLK_TC_REQUEUE, "requeue" }, 1577 { BLK_TC_ISSUE, "issue" }, 1578 { BLK_TC_COMPLETE, "complete" }, 1579 { BLK_TC_FS, "fs" }, 1580 { BLK_TC_PC, "pc" }, 1581 { BLK_TC_AHEAD, "ahead" }, 1582 { BLK_TC_META, "meta" }, 1583 { BLK_TC_DISCARD, "discard" }, 1584 { BLK_TC_DRV_DATA, "drv_data" }, 1585 }; 1586 1587 static int blk_trace_str2mask(const char *str) 1588 { 1589 int i; 1590 int mask = 0; 1591 char *buf, *s, *token; 1592 1593 buf = kstrdup(str, GFP_KERNEL); 1594 if (buf == NULL) 1595 return -ENOMEM; 1596 s = strstrip(buf); 1597 1598 while (1) { 1599 token = strsep(&s, ","); 1600 if (token == NULL) 1601 break; 1602 1603 if (*token == '\0') 1604 continue; 1605 1606 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1607 if (strcasecmp(token, mask_maps[i].str) == 0) { 1608 mask |= mask_maps[i].mask; 1609 break; 1610 } 1611 } 1612 if (i == ARRAY_SIZE(mask_maps)) { 1613 mask = -EINVAL; 1614 break; 1615 } 1616 } 1617 kfree(buf); 1618 1619 return mask; 1620 } 1621 1622 static ssize_t blk_trace_mask2str(char *buf, int mask) 1623 { 1624 int i; 1625 char *p = buf; 1626 1627 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1628 if (mask & mask_maps[i].mask) { 1629 p += sprintf(p, "%s%s", 1630 (p == buf) ? "" : ",", mask_maps[i].str); 1631 } 1632 } 1633 *p++ = '\n'; 1634 1635 return p - buf; 1636 } 1637 1638 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1639 { 1640 if (bdev->bd_disk == NULL) 1641 return NULL; 1642 1643 return bdev_get_queue(bdev); 1644 } 1645 1646 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1647 struct device_attribute *attr, 1648 char *buf) 1649 { 1650 struct hd_struct *p = dev_to_part(dev); 1651 struct request_queue *q; 1652 struct block_device *bdev; 1653 ssize_t ret = -ENXIO; 1654 1655 lock_kernel(); 1656 bdev = bdget(part_devt(p)); 1657 if (bdev == NULL) 1658 goto out_unlock_kernel; 1659 1660 q = blk_trace_get_queue(bdev); 1661 if (q == NULL) 1662 goto out_bdput; 1663 1664 mutex_lock(&bdev->bd_mutex); 1665 1666 if (attr == &dev_attr_enable) { 1667 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1668 goto out_unlock_bdev; 1669 } 1670 1671 if (q->blk_trace == NULL) 1672 ret = sprintf(buf, "disabled\n"); 1673 else if (attr == &dev_attr_act_mask) 1674 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1675 else if (attr == &dev_attr_pid) 1676 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1677 else if (attr == &dev_attr_start_lba) 1678 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1679 else if (attr == &dev_attr_end_lba) 1680 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1681 1682 out_unlock_bdev: 1683 mutex_unlock(&bdev->bd_mutex); 1684 out_bdput: 1685 bdput(bdev); 1686 out_unlock_kernel: 1687 unlock_kernel(); 1688 return ret; 1689 } 1690 1691 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1692 struct device_attribute *attr, 1693 const char *buf, size_t count) 1694 { 1695 struct block_device *bdev; 1696 struct request_queue *q; 1697 struct hd_struct *p; 1698 u64 value; 1699 ssize_t ret = -EINVAL; 1700 1701 if (count == 0) 1702 goto out; 1703 1704 if (attr == &dev_attr_act_mask) { 1705 if (sscanf(buf, "%llx", &value) != 1) { 1706 /* Assume it is a list of trace category names */ 1707 ret = blk_trace_str2mask(buf); 1708 if (ret < 0) 1709 goto out; 1710 value = ret; 1711 } 1712 } else if (sscanf(buf, "%llu", &value) != 1) 1713 goto out; 1714 1715 ret = -ENXIO; 1716 1717 lock_kernel(); 1718 p = dev_to_part(dev); 1719 bdev = bdget(part_devt(p)); 1720 if (bdev == NULL) 1721 goto out_unlock_kernel; 1722 1723 q = blk_trace_get_queue(bdev); 1724 if (q == NULL) 1725 goto out_bdput; 1726 1727 mutex_lock(&bdev->bd_mutex); 1728 1729 if (attr == &dev_attr_enable) { 1730 if (value) 1731 ret = blk_trace_setup_queue(q, bdev); 1732 else 1733 ret = blk_trace_remove_queue(q); 1734 goto out_unlock_bdev; 1735 } 1736 1737 ret = 0; 1738 if (q->blk_trace == NULL) 1739 ret = blk_trace_setup_queue(q, bdev); 1740 1741 if (ret == 0) { 1742 if (attr == &dev_attr_act_mask) 1743 q->blk_trace->act_mask = value; 1744 else if (attr == &dev_attr_pid) 1745 q->blk_trace->pid = value; 1746 else if (attr == &dev_attr_start_lba) 1747 q->blk_trace->start_lba = value; 1748 else if (attr == &dev_attr_end_lba) 1749 q->blk_trace->end_lba = value; 1750 } 1751 1752 out_unlock_bdev: 1753 mutex_unlock(&bdev->bd_mutex); 1754 out_bdput: 1755 bdput(bdev); 1756 out_unlock_kernel: 1757 unlock_kernel(); 1758 out: 1759 return ret ? ret : count; 1760 } 1761 1762 int blk_trace_init_sysfs(struct device *dev) 1763 { 1764 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1765 } 1766 1767 void blk_trace_remove_sysfs(struct device *dev) 1768 { 1769 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1770 } 1771 1772 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1773 1774 #ifdef CONFIG_EVENT_TRACING 1775 1776 void blk_dump_cmd(char *buf, struct request *rq) 1777 { 1778 int i, end; 1779 int len = rq->cmd_len; 1780 unsigned char *cmd = rq->cmd; 1781 1782 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) { 1783 buf[0] = '\0'; 1784 return; 1785 } 1786 1787 for (end = len - 1; end >= 0; end--) 1788 if (cmd[end]) 1789 break; 1790 end++; 1791 1792 for (i = 0; i < len; i++) { 1793 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1794 if (i == end && end != len - 1) { 1795 sprintf(buf, " .."); 1796 break; 1797 } 1798 } 1799 } 1800 1801 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes) 1802 { 1803 int i = 0; 1804 1805 if (rw & WRITE) 1806 rwbs[i++] = 'W'; 1807 else if (rw & REQ_DISCARD) 1808 rwbs[i++] = 'D'; 1809 else if (bytes) 1810 rwbs[i++] = 'R'; 1811 else 1812 rwbs[i++] = 'N'; 1813 1814 if (rw & REQ_RAHEAD) 1815 rwbs[i++] = 'A'; 1816 if (rw & REQ_HARDBARRIER) 1817 rwbs[i++] = 'B'; 1818 if (rw & REQ_SYNC) 1819 rwbs[i++] = 'S'; 1820 if (rw & REQ_META) 1821 rwbs[i++] = 'M'; 1822 if (rw & REQ_SECURE) 1823 rwbs[i++] = 'E'; 1824 1825 rwbs[i] = '\0'; 1826 } 1827 1828 void blk_fill_rwbs_rq(char *rwbs, struct request *rq) 1829 { 1830 int rw = rq->cmd_flags & 0x03; 1831 int bytes; 1832 1833 if (rq->cmd_flags & REQ_DISCARD) 1834 rw |= REQ_DISCARD; 1835 1836 if (rq->cmd_flags & REQ_SECURE) 1837 rw |= REQ_SECURE; 1838 1839 bytes = blk_rq_bytes(rq); 1840 1841 blk_fill_rwbs(rwbs, rw, bytes); 1842 } 1843 1844 #endif /* CONFIG_EVENT_TRACING */ 1845 1846