1 /* 2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 16 * 17 */ 18 #include <linux/kernel.h> 19 #include <linux/blkdev.h> 20 #include <linux/blktrace_api.h> 21 #include <linux/percpu.h> 22 #include <linux/init.h> 23 #include <linux/mutex.h> 24 #include <linux/slab.h> 25 #include <linux/debugfs.h> 26 #include <linux/export.h> 27 #include <linux/time.h> 28 #include <linux/uaccess.h> 29 #include <linux/list.h> 30 31 #include "../../block/blk.h" 32 33 #include <trace/events/block.h> 34 35 #include "trace_output.h" 36 37 #ifdef CONFIG_BLK_DEV_IO_TRACE 38 39 static unsigned int blktrace_seq __read_mostly = 1; 40 41 static struct trace_array *blk_tr; 42 static bool blk_tracer_enabled __read_mostly; 43 44 static LIST_HEAD(running_trace_list); 45 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock); 46 47 /* Select an alternative, minimalistic output than the original one */ 48 #define TRACE_BLK_OPT_CLASSIC 0x1 49 50 static struct tracer_opt blk_tracer_opts[] = { 51 /* Default disable the minimalistic output */ 52 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 53 { } 54 }; 55 56 static struct tracer_flags blk_tracer_flags = { 57 .val = 0, 58 .opts = blk_tracer_opts, 59 }; 60 61 /* Global reference count of probes */ 62 static atomic_t blk_probes_ref = ATOMIC_INIT(0); 63 64 static void blk_register_tracepoints(void); 65 static void blk_unregister_tracepoints(void); 66 67 /* 68 * Send out a notify message. 69 */ 70 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 71 const void *data, size_t len) 72 { 73 struct blk_io_trace *t; 74 struct ring_buffer_event *event = NULL; 75 struct ring_buffer *buffer = NULL; 76 int pc = 0; 77 int cpu = smp_processor_id(); 78 bool blk_tracer = blk_tracer_enabled; 79 80 if (blk_tracer) { 81 buffer = blk_tr->trace_buffer.buffer; 82 pc = preempt_count(); 83 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 84 sizeof(*t) + len, 85 0, pc); 86 if (!event) 87 return; 88 t = ring_buffer_event_data(event); 89 goto record_it; 90 } 91 92 if (!bt->rchan) 93 return; 94 95 t = relay_reserve(bt->rchan, sizeof(*t) + len); 96 if (t) { 97 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 98 t->time = ktime_to_ns(ktime_get()); 99 record_it: 100 t->device = bt->dev; 101 t->action = action; 102 t->pid = pid; 103 t->cpu = cpu; 104 t->pdu_len = len; 105 memcpy((void *) t + sizeof(*t), data, len); 106 107 if (blk_tracer) 108 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc); 109 } 110 } 111 112 /* 113 * Send out a notify for this process, if we haven't done so since a trace 114 * started 115 */ 116 static void trace_note_tsk(struct task_struct *tsk) 117 { 118 unsigned long flags; 119 struct blk_trace *bt; 120 121 tsk->btrace_seq = blktrace_seq; 122 spin_lock_irqsave(&running_trace_lock, flags); 123 list_for_each_entry(bt, &running_trace_list, running_list) { 124 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, 125 sizeof(tsk->comm)); 126 } 127 spin_unlock_irqrestore(&running_trace_lock, flags); 128 } 129 130 static void trace_note_time(struct blk_trace *bt) 131 { 132 struct timespec64 now; 133 unsigned long flags; 134 u32 words[2]; 135 136 /* need to check user space to see if this breaks in y2038 or y2106 */ 137 ktime_get_real_ts64(&now); 138 words[0] = (u32)now.tv_sec; 139 words[1] = now.tv_nsec; 140 141 local_irq_save(flags); 142 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); 143 local_irq_restore(flags); 144 } 145 146 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 147 { 148 int n; 149 va_list args; 150 unsigned long flags; 151 char *buf; 152 153 if (unlikely(bt->trace_state != Blktrace_running && 154 !blk_tracer_enabled)) 155 return; 156 157 /* 158 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note 159 * message to the trace. 160 */ 161 if (!(bt->act_mask & BLK_TC_NOTIFY)) 162 return; 163 164 local_irq_save(flags); 165 buf = this_cpu_ptr(bt->msg_data); 166 va_start(args, fmt); 167 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 168 va_end(args); 169 170 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); 171 local_irq_restore(flags); 172 } 173 EXPORT_SYMBOL_GPL(__trace_note_message); 174 175 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 176 pid_t pid) 177 { 178 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 179 return 1; 180 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 181 return 1; 182 if (bt->pid && pid != bt->pid) 183 return 1; 184 185 return 0; 186 } 187 188 /* 189 * Data direction bit lookup 190 */ 191 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 192 BLK_TC_ACT(BLK_TC_WRITE) }; 193 194 #define BLK_TC_RAHEAD BLK_TC_AHEAD 195 #define BLK_TC_PREFLUSH BLK_TC_FLUSH 196 197 /* The ilog2() calls fall out because they're constant */ 198 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \ 199 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name)) 200 201 /* 202 * The worker for the various blk_add_trace*() types. Fills out a 203 * blk_io_trace structure and places it in a per-cpu subbuffer. 204 */ 205 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 206 int op, int op_flags, u32 what, int error, int pdu_len, 207 void *pdu_data) 208 { 209 struct task_struct *tsk = current; 210 struct ring_buffer_event *event = NULL; 211 struct ring_buffer *buffer = NULL; 212 struct blk_io_trace *t; 213 unsigned long flags = 0; 214 unsigned long *sequence; 215 pid_t pid; 216 int cpu, pc = 0; 217 bool blk_tracer = blk_tracer_enabled; 218 219 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 220 return; 221 222 what |= ddir_act[op_is_write(op) ? WRITE : READ]; 223 what |= MASK_TC_BIT(op_flags, SYNC); 224 what |= MASK_TC_BIT(op_flags, RAHEAD); 225 what |= MASK_TC_BIT(op_flags, META); 226 what |= MASK_TC_BIT(op_flags, PREFLUSH); 227 what |= MASK_TC_BIT(op_flags, FUA); 228 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE) 229 what |= BLK_TC_ACT(BLK_TC_DISCARD); 230 if (op == REQ_OP_FLUSH) 231 what |= BLK_TC_ACT(BLK_TC_FLUSH); 232 233 pid = tsk->pid; 234 if (act_log_check(bt, what, sector, pid)) 235 return; 236 cpu = raw_smp_processor_id(); 237 238 if (blk_tracer) { 239 tracing_record_cmdline(current); 240 241 buffer = blk_tr->trace_buffer.buffer; 242 pc = preempt_count(); 243 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 244 sizeof(*t) + pdu_len, 245 0, pc); 246 if (!event) 247 return; 248 t = ring_buffer_event_data(event); 249 goto record_it; 250 } 251 252 if (unlikely(tsk->btrace_seq != blktrace_seq)) 253 trace_note_tsk(tsk); 254 255 /* 256 * A word about the locking here - we disable interrupts to reserve 257 * some space in the relay per-cpu buffer, to prevent an irq 258 * from coming in and stepping on our toes. 259 */ 260 local_irq_save(flags); 261 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 262 if (t) { 263 sequence = per_cpu_ptr(bt->sequence, cpu); 264 265 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 266 t->sequence = ++(*sequence); 267 t->time = ktime_to_ns(ktime_get()); 268 record_it: 269 /* 270 * These two are not needed in ftrace as they are in the 271 * generic trace_entry, filled by tracing_generic_entry_update, 272 * but for the trace_event->bin() synthesizer benefit we do it 273 * here too. 274 */ 275 t->cpu = cpu; 276 t->pid = pid; 277 278 t->sector = sector; 279 t->bytes = bytes; 280 t->action = what; 281 t->device = bt->dev; 282 t->error = error; 283 t->pdu_len = pdu_len; 284 285 if (pdu_len) 286 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 287 288 if (blk_tracer) { 289 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc); 290 return; 291 } 292 } 293 294 local_irq_restore(flags); 295 } 296 297 static void blk_trace_free(struct blk_trace *bt) 298 { 299 debugfs_remove(bt->msg_file); 300 debugfs_remove(bt->dropped_file); 301 relay_close(bt->rchan); 302 debugfs_remove(bt->dir); 303 free_percpu(bt->sequence); 304 free_percpu(bt->msg_data); 305 kfree(bt); 306 } 307 308 static void blk_trace_cleanup(struct blk_trace *bt) 309 { 310 blk_trace_free(bt); 311 if (atomic_dec_and_test(&blk_probes_ref)) 312 blk_unregister_tracepoints(); 313 } 314 315 int blk_trace_remove(struct request_queue *q) 316 { 317 struct blk_trace *bt; 318 319 bt = xchg(&q->blk_trace, NULL); 320 if (!bt) 321 return -EINVAL; 322 323 if (bt->trace_state != Blktrace_running) 324 blk_trace_cleanup(bt); 325 326 return 0; 327 } 328 EXPORT_SYMBOL_GPL(blk_trace_remove); 329 330 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 331 size_t count, loff_t *ppos) 332 { 333 struct blk_trace *bt = filp->private_data; 334 char buf[16]; 335 336 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 337 338 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 339 } 340 341 static const struct file_operations blk_dropped_fops = { 342 .owner = THIS_MODULE, 343 .open = simple_open, 344 .read = blk_dropped_read, 345 .llseek = default_llseek, 346 }; 347 348 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 349 size_t count, loff_t *ppos) 350 { 351 char *msg; 352 struct blk_trace *bt; 353 354 if (count >= BLK_TN_MAX_MSG) 355 return -EINVAL; 356 357 msg = memdup_user_nul(buffer, count); 358 if (IS_ERR(msg)) 359 return PTR_ERR(msg); 360 361 bt = filp->private_data; 362 __trace_note_message(bt, "%s", msg); 363 kfree(msg); 364 365 return count; 366 } 367 368 static const struct file_operations blk_msg_fops = { 369 .owner = THIS_MODULE, 370 .open = simple_open, 371 .write = blk_msg_write, 372 .llseek = noop_llseek, 373 }; 374 375 /* 376 * Keep track of how many times we encountered a full subbuffer, to aid 377 * the user space app in telling how many lost events there were. 378 */ 379 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 380 void *prev_subbuf, size_t prev_padding) 381 { 382 struct blk_trace *bt; 383 384 if (!relay_buf_full(buf)) 385 return 1; 386 387 bt = buf->chan->private_data; 388 atomic_inc(&bt->dropped); 389 return 0; 390 } 391 392 static int blk_remove_buf_file_callback(struct dentry *dentry) 393 { 394 debugfs_remove(dentry); 395 396 return 0; 397 } 398 399 static struct dentry *blk_create_buf_file_callback(const char *filename, 400 struct dentry *parent, 401 umode_t mode, 402 struct rchan_buf *buf, 403 int *is_global) 404 { 405 return debugfs_create_file(filename, mode, parent, buf, 406 &relay_file_operations); 407 } 408 409 static struct rchan_callbacks blk_relay_callbacks = { 410 .subbuf_start = blk_subbuf_start_callback, 411 .create_buf_file = blk_create_buf_file_callback, 412 .remove_buf_file = blk_remove_buf_file_callback, 413 }; 414 415 static void blk_trace_setup_lba(struct blk_trace *bt, 416 struct block_device *bdev) 417 { 418 struct hd_struct *part = NULL; 419 420 if (bdev) 421 part = bdev->bd_part; 422 423 if (part) { 424 bt->start_lba = part->start_sect; 425 bt->end_lba = part->start_sect + part->nr_sects; 426 } else { 427 bt->start_lba = 0; 428 bt->end_lba = -1ULL; 429 } 430 } 431 432 /* 433 * Setup everything required to start tracing 434 */ 435 static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 436 struct block_device *bdev, 437 struct blk_user_trace_setup *buts) 438 { 439 struct blk_trace *bt = NULL; 440 struct dentry *dir = NULL; 441 int ret; 442 443 if (!buts->buf_size || !buts->buf_nr) 444 return -EINVAL; 445 446 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 447 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 448 449 /* 450 * some device names have larger paths - convert the slashes 451 * to underscores for this to work as expected 452 */ 453 strreplace(buts->name, '/', '_'); 454 455 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 456 if (!bt) 457 return -ENOMEM; 458 459 ret = -ENOMEM; 460 bt->sequence = alloc_percpu(unsigned long); 461 if (!bt->sequence) 462 goto err; 463 464 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 465 if (!bt->msg_data) 466 goto err; 467 468 ret = -ENOENT; 469 470 if (!blk_debugfs_root) 471 goto err; 472 473 dir = debugfs_lookup(buts->name, blk_debugfs_root); 474 if (!dir) 475 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root); 476 if (!dir) 477 goto err; 478 479 bt->dev = dev; 480 atomic_set(&bt->dropped, 0); 481 INIT_LIST_HEAD(&bt->running_list); 482 483 ret = -EIO; 484 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 485 &blk_dropped_fops); 486 if (!bt->dropped_file) 487 goto err; 488 489 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 490 if (!bt->msg_file) 491 goto err; 492 493 bt->rchan = relay_open("trace", dir, buts->buf_size, 494 buts->buf_nr, &blk_relay_callbacks, bt); 495 if (!bt->rchan) 496 goto err; 497 498 bt->act_mask = buts->act_mask; 499 if (!bt->act_mask) 500 bt->act_mask = (u16) -1; 501 502 blk_trace_setup_lba(bt, bdev); 503 504 /* overwrite with user settings */ 505 if (buts->start_lba) 506 bt->start_lba = buts->start_lba; 507 if (buts->end_lba) 508 bt->end_lba = buts->end_lba; 509 510 bt->pid = buts->pid; 511 bt->trace_state = Blktrace_setup; 512 513 ret = -EBUSY; 514 if (cmpxchg(&q->blk_trace, NULL, bt)) 515 goto err; 516 517 if (atomic_inc_return(&blk_probes_ref) == 1) 518 blk_register_tracepoints(); 519 520 ret = 0; 521 err: 522 if (dir && !bt->dir) 523 dput(dir); 524 if (ret) 525 blk_trace_free(bt); 526 return ret; 527 } 528 529 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 530 struct block_device *bdev, 531 char __user *arg) 532 { 533 struct blk_user_trace_setup buts; 534 int ret; 535 536 ret = copy_from_user(&buts, arg, sizeof(buts)); 537 if (ret) 538 return -EFAULT; 539 540 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 541 if (ret) 542 return ret; 543 544 if (copy_to_user(arg, &buts, sizeof(buts))) { 545 blk_trace_remove(q); 546 return -EFAULT; 547 } 548 return 0; 549 } 550 EXPORT_SYMBOL_GPL(blk_trace_setup); 551 552 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 553 static int compat_blk_trace_setup(struct request_queue *q, char *name, 554 dev_t dev, struct block_device *bdev, 555 char __user *arg) 556 { 557 struct blk_user_trace_setup buts; 558 struct compat_blk_user_trace_setup cbuts; 559 int ret; 560 561 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 562 return -EFAULT; 563 564 buts = (struct blk_user_trace_setup) { 565 .act_mask = cbuts.act_mask, 566 .buf_size = cbuts.buf_size, 567 .buf_nr = cbuts.buf_nr, 568 .start_lba = cbuts.start_lba, 569 .end_lba = cbuts.end_lba, 570 .pid = cbuts.pid, 571 }; 572 573 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 574 if (ret) 575 return ret; 576 577 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) { 578 blk_trace_remove(q); 579 return -EFAULT; 580 } 581 582 return 0; 583 } 584 #endif 585 586 int blk_trace_startstop(struct request_queue *q, int start) 587 { 588 int ret; 589 struct blk_trace *bt = q->blk_trace; 590 591 if (bt == NULL) 592 return -EINVAL; 593 594 /* 595 * For starting a trace, we can transition from a setup or stopped 596 * trace. For stopping a trace, the state must be running 597 */ 598 ret = -EINVAL; 599 if (start) { 600 if (bt->trace_state == Blktrace_setup || 601 bt->trace_state == Blktrace_stopped) { 602 blktrace_seq++; 603 smp_mb(); 604 bt->trace_state = Blktrace_running; 605 spin_lock_irq(&running_trace_lock); 606 list_add(&bt->running_list, &running_trace_list); 607 spin_unlock_irq(&running_trace_lock); 608 609 trace_note_time(bt); 610 ret = 0; 611 } 612 } else { 613 if (bt->trace_state == Blktrace_running) { 614 bt->trace_state = Blktrace_stopped; 615 spin_lock_irq(&running_trace_lock); 616 list_del_init(&bt->running_list); 617 spin_unlock_irq(&running_trace_lock); 618 relay_flush(bt->rchan); 619 ret = 0; 620 } 621 } 622 623 return ret; 624 } 625 EXPORT_SYMBOL_GPL(blk_trace_startstop); 626 627 /** 628 * blk_trace_ioctl: - handle the ioctls associated with tracing 629 * @bdev: the block device 630 * @cmd: the ioctl cmd 631 * @arg: the argument data, if any 632 * 633 **/ 634 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 635 { 636 struct request_queue *q; 637 int ret, start = 0; 638 char b[BDEVNAME_SIZE]; 639 640 q = bdev_get_queue(bdev); 641 if (!q) 642 return -ENXIO; 643 644 mutex_lock(&bdev->bd_mutex); 645 646 switch (cmd) { 647 case BLKTRACESETUP: 648 bdevname(bdev, b); 649 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 650 break; 651 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 652 case BLKTRACESETUP32: 653 bdevname(bdev, b); 654 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 655 break; 656 #endif 657 case BLKTRACESTART: 658 start = 1; 659 case BLKTRACESTOP: 660 ret = blk_trace_startstop(q, start); 661 break; 662 case BLKTRACETEARDOWN: 663 ret = blk_trace_remove(q); 664 break; 665 default: 666 ret = -ENOTTY; 667 break; 668 } 669 670 mutex_unlock(&bdev->bd_mutex); 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 * @rq: the source request 694 * @error: return status to log 695 * @nr_bytes: number of completed bytes 696 * @what: the action 697 * 698 * Description: 699 * Records an action against a request. Will log the bio offset + size. 700 * 701 **/ 702 static void blk_add_trace_rq(struct request *rq, int error, 703 unsigned int nr_bytes, u32 what) 704 { 705 struct blk_trace *bt = rq->q->blk_trace; 706 707 if (likely(!bt)) 708 return; 709 710 if (blk_rq_is_passthrough(rq)) 711 what |= BLK_TC_ACT(BLK_TC_PC); 712 else 713 what |= BLK_TC_ACT(BLK_TC_FS); 714 715 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq), 716 rq->cmd_flags, what, error, 0, NULL); 717 } 718 719 static void blk_add_trace_rq_insert(void *ignore, 720 struct request_queue *q, struct request *rq) 721 { 722 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT); 723 } 724 725 static void blk_add_trace_rq_issue(void *ignore, 726 struct request_queue *q, struct request *rq) 727 { 728 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE); 729 } 730 731 static void blk_add_trace_rq_requeue(void *ignore, 732 struct request_queue *q, 733 struct request *rq) 734 { 735 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE); 736 } 737 738 static void blk_add_trace_rq_complete(void *ignore, struct request *rq, 739 int error, unsigned int nr_bytes) 740 { 741 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE); 742 } 743 744 /** 745 * blk_add_trace_bio - Add a trace for a bio oriented action 746 * @q: queue the io is for 747 * @bio: the source bio 748 * @what: the action 749 * @error: error, if any 750 * 751 * Description: 752 * Records an action against a bio. Will log the bio offset + size. 753 * 754 **/ 755 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 756 u32 what, int error) 757 { 758 struct blk_trace *bt = q->blk_trace; 759 760 if (likely(!bt)) 761 return; 762 763 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 764 bio_op(bio), bio->bi_opf, what, error, 0, NULL); 765 } 766 767 static void blk_add_trace_bio_bounce(void *ignore, 768 struct request_queue *q, struct bio *bio) 769 { 770 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0); 771 } 772 773 static void blk_add_trace_bio_complete(void *ignore, 774 struct request_queue *q, struct bio *bio, 775 int error) 776 { 777 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error); 778 } 779 780 static void blk_add_trace_bio_backmerge(void *ignore, 781 struct request_queue *q, 782 struct request *rq, 783 struct bio *bio) 784 { 785 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0); 786 } 787 788 static void blk_add_trace_bio_frontmerge(void *ignore, 789 struct request_queue *q, 790 struct request *rq, 791 struct bio *bio) 792 { 793 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0); 794 } 795 796 static void blk_add_trace_bio_queue(void *ignore, 797 struct request_queue *q, struct bio *bio) 798 { 799 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0); 800 } 801 802 static void blk_add_trace_getrq(void *ignore, 803 struct request_queue *q, 804 struct bio *bio, int rw) 805 { 806 if (bio) 807 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0); 808 else { 809 struct blk_trace *bt = q->blk_trace; 810 811 if (bt) 812 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0, 813 NULL); 814 } 815 } 816 817 818 static void blk_add_trace_sleeprq(void *ignore, 819 struct request_queue *q, 820 struct bio *bio, int rw) 821 { 822 if (bio) 823 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0); 824 else { 825 struct blk_trace *bt = q->blk_trace; 826 827 if (bt) 828 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ, 829 0, 0, NULL); 830 } 831 } 832 833 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 834 { 835 struct blk_trace *bt = q->blk_trace; 836 837 if (bt) 838 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 839 } 840 841 static void blk_add_trace_unplug(void *ignore, struct request_queue *q, 842 unsigned int depth, bool explicit) 843 { 844 struct blk_trace *bt = q->blk_trace; 845 846 if (bt) { 847 __be64 rpdu = cpu_to_be64(depth); 848 u32 what; 849 850 if (explicit) 851 what = BLK_TA_UNPLUG_IO; 852 else 853 what = BLK_TA_UNPLUG_TIMER; 854 855 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu); 856 } 857 } 858 859 static void blk_add_trace_split(void *ignore, 860 struct request_queue *q, struct bio *bio, 861 unsigned int pdu) 862 { 863 struct blk_trace *bt = q->blk_trace; 864 865 if (bt) { 866 __be64 rpdu = cpu_to_be64(pdu); 867 868 __blk_add_trace(bt, bio->bi_iter.bi_sector, 869 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf, 870 BLK_TA_SPLIT, bio->bi_error, sizeof(rpdu), 871 &rpdu); 872 } 873 } 874 875 /** 876 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation 877 * @ignore: trace callback data parameter (not used) 878 * @q: queue the io is for 879 * @bio: the source bio 880 * @dev: target device 881 * @from: source sector 882 * 883 * Description: 884 * Device mapper or raid target sometimes need to split a bio because 885 * it spans a stripe (or similar). Add a trace for that action. 886 * 887 **/ 888 static void blk_add_trace_bio_remap(void *ignore, 889 struct request_queue *q, struct bio *bio, 890 dev_t dev, sector_t from) 891 { 892 struct blk_trace *bt = q->blk_trace; 893 struct blk_io_trace_remap r; 894 895 if (likely(!bt)) 896 return; 897 898 r.device_from = cpu_to_be32(dev); 899 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 900 r.sector_from = cpu_to_be64(from); 901 902 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 903 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_error, 904 sizeof(r), &r); 905 } 906 907 /** 908 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 909 * @ignore: trace callback data parameter (not used) 910 * @q: queue the io is for 911 * @rq: the source request 912 * @dev: target device 913 * @from: source sector 914 * 915 * Description: 916 * Device mapper remaps request to other devices. 917 * Add a trace for that action. 918 * 919 **/ 920 static void blk_add_trace_rq_remap(void *ignore, 921 struct request_queue *q, 922 struct request *rq, dev_t dev, 923 sector_t from) 924 { 925 struct blk_trace *bt = q->blk_trace; 926 struct blk_io_trace_remap r; 927 928 if (likely(!bt)) 929 return; 930 931 r.device_from = cpu_to_be32(dev); 932 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 933 r.sector_from = cpu_to_be64(from); 934 935 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 936 rq_data_dir(rq), 0, BLK_TA_REMAP, 0, 937 sizeof(r), &r); 938 } 939 940 /** 941 * blk_add_driver_data - Add binary message with driver-specific data 942 * @q: queue the io is for 943 * @rq: io request 944 * @data: driver-specific data 945 * @len: length of driver-specific data 946 * 947 * Description: 948 * Some drivers might want to write driver-specific data per request. 949 * 950 **/ 951 void blk_add_driver_data(struct request_queue *q, 952 struct request *rq, 953 void *data, size_t len) 954 { 955 struct blk_trace *bt = q->blk_trace; 956 957 if (likely(!bt)) 958 return; 959 960 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0, 961 BLK_TA_DRV_DATA, 0, len, data); 962 } 963 EXPORT_SYMBOL_GPL(blk_add_driver_data); 964 965 static void blk_register_tracepoints(void) 966 { 967 int ret; 968 969 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 970 WARN_ON(ret); 971 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 972 WARN_ON(ret); 973 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 974 WARN_ON(ret); 975 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 976 WARN_ON(ret); 977 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 978 WARN_ON(ret); 979 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 980 WARN_ON(ret); 981 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 982 WARN_ON(ret); 983 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 984 WARN_ON(ret); 985 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 986 WARN_ON(ret); 987 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 988 WARN_ON(ret); 989 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 990 WARN_ON(ret); 991 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 992 WARN_ON(ret); 993 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL); 994 WARN_ON(ret); 995 ret = register_trace_block_split(blk_add_trace_split, NULL); 996 WARN_ON(ret); 997 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 998 WARN_ON(ret); 999 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1000 WARN_ON(ret); 1001 } 1002 1003 static void blk_unregister_tracepoints(void) 1004 { 1005 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1006 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1007 unregister_trace_block_split(blk_add_trace_split, NULL); 1008 unregister_trace_block_unplug(blk_add_trace_unplug, NULL); 1009 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1010 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1011 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1012 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1013 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1014 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1015 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1016 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1017 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1018 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1019 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1020 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1021 1022 tracepoint_synchronize_unregister(); 1023 } 1024 1025 /* 1026 * struct blk_io_tracer formatting routines 1027 */ 1028 1029 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1030 { 1031 int i = 0; 1032 int tc = t->action >> BLK_TC_SHIFT; 1033 1034 if (t->action == BLK_TN_MESSAGE) { 1035 rwbs[i++] = 'N'; 1036 goto out; 1037 } 1038 1039 if (tc & BLK_TC_FLUSH) 1040 rwbs[i++] = 'F'; 1041 1042 if (tc & BLK_TC_DISCARD) 1043 rwbs[i++] = 'D'; 1044 else if (tc & BLK_TC_WRITE) 1045 rwbs[i++] = 'W'; 1046 else if (t->bytes) 1047 rwbs[i++] = 'R'; 1048 else 1049 rwbs[i++] = 'N'; 1050 1051 if (tc & BLK_TC_FUA) 1052 rwbs[i++] = 'F'; 1053 if (tc & BLK_TC_AHEAD) 1054 rwbs[i++] = 'A'; 1055 if (tc & BLK_TC_SYNC) 1056 rwbs[i++] = 'S'; 1057 if (tc & BLK_TC_META) 1058 rwbs[i++] = 'M'; 1059 out: 1060 rwbs[i] = '\0'; 1061 } 1062 1063 static inline 1064 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1065 { 1066 return (const struct blk_io_trace *)ent; 1067 } 1068 1069 static inline const void *pdu_start(const struct trace_entry *ent) 1070 { 1071 return te_blk_io_trace(ent) + 1; 1072 } 1073 1074 static inline u32 t_action(const struct trace_entry *ent) 1075 { 1076 return te_blk_io_trace(ent)->action; 1077 } 1078 1079 static inline u32 t_bytes(const struct trace_entry *ent) 1080 { 1081 return te_blk_io_trace(ent)->bytes; 1082 } 1083 1084 static inline u32 t_sec(const struct trace_entry *ent) 1085 { 1086 return te_blk_io_trace(ent)->bytes >> 9; 1087 } 1088 1089 static inline unsigned long long t_sector(const struct trace_entry *ent) 1090 { 1091 return te_blk_io_trace(ent)->sector; 1092 } 1093 1094 static inline __u16 t_error(const struct trace_entry *ent) 1095 { 1096 return te_blk_io_trace(ent)->error; 1097 } 1098 1099 static __u64 get_pdu_int(const struct trace_entry *ent) 1100 { 1101 const __u64 *val = pdu_start(ent); 1102 return be64_to_cpu(*val); 1103 } 1104 1105 static void get_pdu_remap(const struct trace_entry *ent, 1106 struct blk_io_trace_remap *r) 1107 { 1108 const struct blk_io_trace_remap *__r = pdu_start(ent); 1109 __u64 sector_from = __r->sector_from; 1110 1111 r->device_from = be32_to_cpu(__r->device_from); 1112 r->device_to = be32_to_cpu(__r->device_to); 1113 r->sector_from = be64_to_cpu(sector_from); 1114 } 1115 1116 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1117 1118 static void blk_log_action_classic(struct trace_iterator *iter, const char *act) 1119 { 1120 char rwbs[RWBS_LEN]; 1121 unsigned long long ts = iter->ts; 1122 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1123 unsigned secs = (unsigned long)ts; 1124 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1125 1126 fill_rwbs(rwbs, t); 1127 1128 trace_seq_printf(&iter->seq, 1129 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1130 MAJOR(t->device), MINOR(t->device), iter->cpu, 1131 secs, nsec_rem, iter->ent->pid, act, rwbs); 1132 } 1133 1134 static void blk_log_action(struct trace_iterator *iter, const char *act) 1135 { 1136 char rwbs[RWBS_LEN]; 1137 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1138 1139 fill_rwbs(rwbs, t); 1140 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1141 MAJOR(t->device), MINOR(t->device), act, rwbs); 1142 } 1143 1144 static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1145 { 1146 const unsigned char *pdu_buf; 1147 int pdu_len; 1148 int i, end; 1149 1150 pdu_buf = pdu_start(ent); 1151 pdu_len = te_blk_io_trace(ent)->pdu_len; 1152 1153 if (!pdu_len) 1154 return; 1155 1156 /* find the last zero that needs to be printed */ 1157 for (end = pdu_len - 1; end >= 0; end--) 1158 if (pdu_buf[end]) 1159 break; 1160 end++; 1161 1162 trace_seq_putc(s, '('); 1163 1164 for (i = 0; i < pdu_len; i++) { 1165 1166 trace_seq_printf(s, "%s%02x", 1167 i == 0 ? "" : " ", pdu_buf[i]); 1168 1169 /* 1170 * stop when the rest is just zeroes and indicate so 1171 * with a ".." appended 1172 */ 1173 if (i == end && end != pdu_len - 1) { 1174 trace_seq_puts(s, " ..) "); 1175 return; 1176 } 1177 } 1178 1179 trace_seq_puts(s, ") "); 1180 } 1181 1182 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1183 { 1184 char cmd[TASK_COMM_LEN]; 1185 1186 trace_find_cmdline(ent->pid, cmd); 1187 1188 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1189 trace_seq_printf(s, "%u ", t_bytes(ent)); 1190 blk_log_dump_pdu(s, ent); 1191 trace_seq_printf(s, "[%s]\n", cmd); 1192 } else { 1193 if (t_sec(ent)) 1194 trace_seq_printf(s, "%llu + %u [%s]\n", 1195 t_sector(ent), t_sec(ent), cmd); 1196 else 1197 trace_seq_printf(s, "[%s]\n", cmd); 1198 } 1199 } 1200 1201 static void blk_log_with_error(struct trace_seq *s, 1202 const struct trace_entry *ent) 1203 { 1204 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1205 blk_log_dump_pdu(s, ent); 1206 trace_seq_printf(s, "[%d]\n", t_error(ent)); 1207 } else { 1208 if (t_sec(ent)) 1209 trace_seq_printf(s, "%llu + %u [%d]\n", 1210 t_sector(ent), 1211 t_sec(ent), t_error(ent)); 1212 else 1213 trace_seq_printf(s, "%llu [%d]\n", 1214 t_sector(ent), t_error(ent)); 1215 } 1216 } 1217 1218 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1219 { 1220 struct blk_io_trace_remap r = { .device_from = 0, }; 1221 1222 get_pdu_remap(ent, &r); 1223 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1224 t_sector(ent), t_sec(ent), 1225 MAJOR(r.device_from), MINOR(r.device_from), 1226 (unsigned long long)r.sector_from); 1227 } 1228 1229 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1230 { 1231 char cmd[TASK_COMM_LEN]; 1232 1233 trace_find_cmdline(ent->pid, cmd); 1234 1235 trace_seq_printf(s, "[%s]\n", cmd); 1236 } 1237 1238 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1239 { 1240 char cmd[TASK_COMM_LEN]; 1241 1242 trace_find_cmdline(ent->pid, cmd); 1243 1244 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1245 } 1246 1247 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1248 { 1249 char cmd[TASK_COMM_LEN]; 1250 1251 trace_find_cmdline(ent->pid, cmd); 1252 1253 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1254 get_pdu_int(ent), cmd); 1255 } 1256 1257 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1258 { 1259 const struct blk_io_trace *t = te_blk_io_trace(ent); 1260 1261 trace_seq_putmem(s, t + 1, t->pdu_len); 1262 trace_seq_putc(s, '\n'); 1263 } 1264 1265 /* 1266 * struct tracer operations 1267 */ 1268 1269 static void blk_tracer_print_header(struct seq_file *m) 1270 { 1271 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1272 return; 1273 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1274 "# | | | | | |\n"); 1275 } 1276 1277 static void blk_tracer_start(struct trace_array *tr) 1278 { 1279 blk_tracer_enabled = true; 1280 } 1281 1282 static int blk_tracer_init(struct trace_array *tr) 1283 { 1284 blk_tr = tr; 1285 blk_tracer_start(tr); 1286 return 0; 1287 } 1288 1289 static void blk_tracer_stop(struct trace_array *tr) 1290 { 1291 blk_tracer_enabled = false; 1292 } 1293 1294 static void blk_tracer_reset(struct trace_array *tr) 1295 { 1296 blk_tracer_stop(tr); 1297 } 1298 1299 static const struct { 1300 const char *act[2]; 1301 void (*print)(struct trace_seq *s, const struct trace_entry *ent); 1302 } what2act[] = { 1303 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1304 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1305 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1306 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1307 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1308 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1309 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1310 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1311 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1312 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1313 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1314 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1315 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1316 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1317 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1318 }; 1319 1320 static enum print_line_t print_one_line(struct trace_iterator *iter, 1321 bool classic) 1322 { 1323 struct trace_array *tr = iter->tr; 1324 struct trace_seq *s = &iter->seq; 1325 const struct blk_io_trace *t; 1326 u16 what; 1327 bool long_act; 1328 blk_log_action_t *log_action; 1329 1330 t = te_blk_io_trace(iter->ent); 1331 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1332 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE); 1333 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1334 1335 if (t->action == BLK_TN_MESSAGE) { 1336 log_action(iter, long_act ? "message" : "m"); 1337 blk_log_msg(s, iter->ent); 1338 return trace_handle_return(s); 1339 } 1340 1341 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1342 trace_seq_printf(s, "Unknown action %x\n", what); 1343 else { 1344 log_action(iter, what2act[what].act[long_act]); 1345 what2act[what].print(s, iter->ent); 1346 } 1347 1348 return trace_handle_return(s); 1349 } 1350 1351 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1352 int flags, struct trace_event *event) 1353 { 1354 return print_one_line(iter, false); 1355 } 1356 1357 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1358 { 1359 struct trace_seq *s = &iter->seq; 1360 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1361 const int offset = offsetof(struct blk_io_trace, sector); 1362 struct blk_io_trace old = { 1363 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1364 .time = iter->ts, 1365 }; 1366 1367 trace_seq_putmem(s, &old, offset); 1368 trace_seq_putmem(s, &t->sector, 1369 sizeof(old) - offset + t->pdu_len); 1370 } 1371 1372 static enum print_line_t 1373 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1374 struct trace_event *event) 1375 { 1376 blk_trace_synthesize_old_trace(iter); 1377 1378 return trace_handle_return(&iter->seq); 1379 } 1380 1381 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1382 { 1383 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1384 return TRACE_TYPE_UNHANDLED; 1385 1386 return print_one_line(iter, true); 1387 } 1388 1389 static int 1390 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) 1391 { 1392 /* don't output context-info for blk_classic output */ 1393 if (bit == TRACE_BLK_OPT_CLASSIC) { 1394 if (set) 1395 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1396 else 1397 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO; 1398 } 1399 return 0; 1400 } 1401 1402 static struct tracer blk_tracer __read_mostly = { 1403 .name = "blk", 1404 .init = blk_tracer_init, 1405 .reset = blk_tracer_reset, 1406 .start = blk_tracer_start, 1407 .stop = blk_tracer_stop, 1408 .print_header = blk_tracer_print_header, 1409 .print_line = blk_tracer_print_line, 1410 .flags = &blk_tracer_flags, 1411 .set_flag = blk_tracer_set_flag, 1412 }; 1413 1414 static struct trace_event_functions trace_blk_event_funcs = { 1415 .trace = blk_trace_event_print, 1416 .binary = blk_trace_event_print_binary, 1417 }; 1418 1419 static struct trace_event trace_blk_event = { 1420 .type = TRACE_BLK, 1421 .funcs = &trace_blk_event_funcs, 1422 }; 1423 1424 static int __init init_blk_tracer(void) 1425 { 1426 if (!register_trace_event(&trace_blk_event)) { 1427 pr_warn("Warning: could not register block events\n"); 1428 return 1; 1429 } 1430 1431 if (register_tracer(&blk_tracer) != 0) { 1432 pr_warn("Warning: could not register the block tracer\n"); 1433 unregister_trace_event(&trace_blk_event); 1434 return 1; 1435 } 1436 1437 return 0; 1438 } 1439 1440 device_initcall(init_blk_tracer); 1441 1442 static int blk_trace_remove_queue(struct request_queue *q) 1443 { 1444 struct blk_trace *bt; 1445 1446 bt = xchg(&q->blk_trace, NULL); 1447 if (bt == NULL) 1448 return -EINVAL; 1449 1450 if (atomic_dec_and_test(&blk_probes_ref)) 1451 blk_unregister_tracepoints(); 1452 1453 blk_trace_free(bt); 1454 return 0; 1455 } 1456 1457 /* 1458 * Setup everything required to start tracing 1459 */ 1460 static int blk_trace_setup_queue(struct request_queue *q, 1461 struct block_device *bdev) 1462 { 1463 struct blk_trace *bt = NULL; 1464 int ret = -ENOMEM; 1465 1466 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1467 if (!bt) 1468 return -ENOMEM; 1469 1470 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1471 if (!bt->msg_data) 1472 goto free_bt; 1473 1474 bt->dev = bdev->bd_dev; 1475 bt->act_mask = (u16)-1; 1476 1477 blk_trace_setup_lba(bt, bdev); 1478 1479 ret = -EBUSY; 1480 if (cmpxchg(&q->blk_trace, NULL, bt)) 1481 goto free_bt; 1482 1483 if (atomic_inc_return(&blk_probes_ref) == 1) 1484 blk_register_tracepoints(); 1485 return 0; 1486 1487 free_bt: 1488 blk_trace_free(bt); 1489 return ret; 1490 } 1491 1492 /* 1493 * sysfs interface to enable and configure tracing 1494 */ 1495 1496 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1497 struct device_attribute *attr, 1498 char *buf); 1499 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1500 struct device_attribute *attr, 1501 const char *buf, size_t count); 1502 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1503 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1504 sysfs_blk_trace_attr_show, \ 1505 sysfs_blk_trace_attr_store) 1506 1507 static BLK_TRACE_DEVICE_ATTR(enable); 1508 static BLK_TRACE_DEVICE_ATTR(act_mask); 1509 static BLK_TRACE_DEVICE_ATTR(pid); 1510 static BLK_TRACE_DEVICE_ATTR(start_lba); 1511 static BLK_TRACE_DEVICE_ATTR(end_lba); 1512 1513 static struct attribute *blk_trace_attrs[] = { 1514 &dev_attr_enable.attr, 1515 &dev_attr_act_mask.attr, 1516 &dev_attr_pid.attr, 1517 &dev_attr_start_lba.attr, 1518 &dev_attr_end_lba.attr, 1519 NULL 1520 }; 1521 1522 struct attribute_group blk_trace_attr_group = { 1523 .name = "trace", 1524 .attrs = blk_trace_attrs, 1525 }; 1526 1527 static const struct { 1528 int mask; 1529 const char *str; 1530 } mask_maps[] = { 1531 { BLK_TC_READ, "read" }, 1532 { BLK_TC_WRITE, "write" }, 1533 { BLK_TC_FLUSH, "flush" }, 1534 { BLK_TC_SYNC, "sync" }, 1535 { BLK_TC_QUEUE, "queue" }, 1536 { BLK_TC_REQUEUE, "requeue" }, 1537 { BLK_TC_ISSUE, "issue" }, 1538 { BLK_TC_COMPLETE, "complete" }, 1539 { BLK_TC_FS, "fs" }, 1540 { BLK_TC_PC, "pc" }, 1541 { BLK_TC_NOTIFY, "notify" }, 1542 { BLK_TC_AHEAD, "ahead" }, 1543 { BLK_TC_META, "meta" }, 1544 { BLK_TC_DISCARD, "discard" }, 1545 { BLK_TC_DRV_DATA, "drv_data" }, 1546 { BLK_TC_FUA, "fua" }, 1547 }; 1548 1549 static int blk_trace_str2mask(const char *str) 1550 { 1551 int i; 1552 int mask = 0; 1553 char *buf, *s, *token; 1554 1555 buf = kstrdup(str, GFP_KERNEL); 1556 if (buf == NULL) 1557 return -ENOMEM; 1558 s = strstrip(buf); 1559 1560 while (1) { 1561 token = strsep(&s, ","); 1562 if (token == NULL) 1563 break; 1564 1565 if (*token == '\0') 1566 continue; 1567 1568 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1569 if (strcasecmp(token, mask_maps[i].str) == 0) { 1570 mask |= mask_maps[i].mask; 1571 break; 1572 } 1573 } 1574 if (i == ARRAY_SIZE(mask_maps)) { 1575 mask = -EINVAL; 1576 break; 1577 } 1578 } 1579 kfree(buf); 1580 1581 return mask; 1582 } 1583 1584 static ssize_t blk_trace_mask2str(char *buf, int mask) 1585 { 1586 int i; 1587 char *p = buf; 1588 1589 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1590 if (mask & mask_maps[i].mask) { 1591 p += sprintf(p, "%s%s", 1592 (p == buf) ? "" : ",", mask_maps[i].str); 1593 } 1594 } 1595 *p++ = '\n'; 1596 1597 return p - buf; 1598 } 1599 1600 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1601 { 1602 if (bdev->bd_disk == NULL) 1603 return NULL; 1604 1605 return bdev_get_queue(bdev); 1606 } 1607 1608 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1609 struct device_attribute *attr, 1610 char *buf) 1611 { 1612 struct hd_struct *p = dev_to_part(dev); 1613 struct request_queue *q; 1614 struct block_device *bdev; 1615 ssize_t ret = -ENXIO; 1616 1617 bdev = bdget(part_devt(p)); 1618 if (bdev == NULL) 1619 goto out; 1620 1621 q = blk_trace_get_queue(bdev); 1622 if (q == NULL) 1623 goto out_bdput; 1624 1625 mutex_lock(&bdev->bd_mutex); 1626 1627 if (attr == &dev_attr_enable) { 1628 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1629 goto out_unlock_bdev; 1630 } 1631 1632 if (q->blk_trace == NULL) 1633 ret = sprintf(buf, "disabled\n"); 1634 else if (attr == &dev_attr_act_mask) 1635 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1636 else if (attr == &dev_attr_pid) 1637 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1638 else if (attr == &dev_attr_start_lba) 1639 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1640 else if (attr == &dev_attr_end_lba) 1641 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1642 1643 out_unlock_bdev: 1644 mutex_unlock(&bdev->bd_mutex); 1645 out_bdput: 1646 bdput(bdev); 1647 out: 1648 return ret; 1649 } 1650 1651 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1652 struct device_attribute *attr, 1653 const char *buf, size_t count) 1654 { 1655 struct block_device *bdev; 1656 struct request_queue *q; 1657 struct hd_struct *p; 1658 u64 value; 1659 ssize_t ret = -EINVAL; 1660 1661 if (count == 0) 1662 goto out; 1663 1664 if (attr == &dev_attr_act_mask) { 1665 if (sscanf(buf, "%llx", &value) != 1) { 1666 /* Assume it is a list of trace category names */ 1667 ret = blk_trace_str2mask(buf); 1668 if (ret < 0) 1669 goto out; 1670 value = ret; 1671 } 1672 } else if (sscanf(buf, "%llu", &value) != 1) 1673 goto out; 1674 1675 ret = -ENXIO; 1676 1677 p = dev_to_part(dev); 1678 bdev = bdget(part_devt(p)); 1679 if (bdev == NULL) 1680 goto out; 1681 1682 q = blk_trace_get_queue(bdev); 1683 if (q == NULL) 1684 goto out_bdput; 1685 1686 mutex_lock(&bdev->bd_mutex); 1687 1688 if (attr == &dev_attr_enable) { 1689 if (value) 1690 ret = blk_trace_setup_queue(q, bdev); 1691 else 1692 ret = blk_trace_remove_queue(q); 1693 goto out_unlock_bdev; 1694 } 1695 1696 ret = 0; 1697 if (q->blk_trace == NULL) 1698 ret = blk_trace_setup_queue(q, bdev); 1699 1700 if (ret == 0) { 1701 if (attr == &dev_attr_act_mask) 1702 q->blk_trace->act_mask = value; 1703 else if (attr == &dev_attr_pid) 1704 q->blk_trace->pid = value; 1705 else if (attr == &dev_attr_start_lba) 1706 q->blk_trace->start_lba = value; 1707 else if (attr == &dev_attr_end_lba) 1708 q->blk_trace->end_lba = value; 1709 } 1710 1711 out_unlock_bdev: 1712 mutex_unlock(&bdev->bd_mutex); 1713 out_bdput: 1714 bdput(bdev); 1715 out: 1716 return ret ? ret : count; 1717 } 1718 1719 int blk_trace_init_sysfs(struct device *dev) 1720 { 1721 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1722 } 1723 1724 void blk_trace_remove_sysfs(struct device *dev) 1725 { 1726 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1727 } 1728 1729 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1730 1731 #ifdef CONFIG_EVENT_TRACING 1732 1733 void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes) 1734 { 1735 int i = 0; 1736 1737 if (op & REQ_PREFLUSH) 1738 rwbs[i++] = 'F'; 1739 1740 switch (op & REQ_OP_MASK) { 1741 case REQ_OP_WRITE: 1742 case REQ_OP_WRITE_SAME: 1743 rwbs[i++] = 'W'; 1744 break; 1745 case REQ_OP_DISCARD: 1746 rwbs[i++] = 'D'; 1747 break; 1748 case REQ_OP_SECURE_ERASE: 1749 rwbs[i++] = 'D'; 1750 rwbs[i++] = 'E'; 1751 break; 1752 case REQ_OP_FLUSH: 1753 rwbs[i++] = 'F'; 1754 break; 1755 case REQ_OP_READ: 1756 rwbs[i++] = 'R'; 1757 break; 1758 default: 1759 rwbs[i++] = 'N'; 1760 } 1761 1762 if (op & REQ_FUA) 1763 rwbs[i++] = 'F'; 1764 if (op & REQ_RAHEAD) 1765 rwbs[i++] = 'A'; 1766 if (op & REQ_SYNC) 1767 rwbs[i++] = 'S'; 1768 if (op & REQ_META) 1769 rwbs[i++] = 'M'; 1770 1771 rwbs[i] = '\0'; 1772 } 1773 EXPORT_SYMBOL_GPL(blk_fill_rwbs); 1774 1775 #endif /* CONFIG_EVENT_TRACING */ 1776 1777