1 /* 2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 16 * 17 */ 18 #include <linux/kernel.h> 19 #include <linux/blkdev.h> 20 #include <linux/blktrace_api.h> 21 #include <linux/percpu.h> 22 #include <linux/init.h> 23 #include <linux/mutex.h> 24 #include <linux/slab.h> 25 #include <linux/debugfs.h> 26 #include <linux/export.h> 27 #include <linux/time.h> 28 #include <linux/uaccess.h> 29 #include <linux/list.h> 30 31 #include <trace/events/block.h> 32 33 #include "trace_output.h" 34 35 #ifdef CONFIG_BLK_DEV_IO_TRACE 36 37 static unsigned int blktrace_seq __read_mostly = 1; 38 39 static struct trace_array *blk_tr; 40 static bool blk_tracer_enabled __read_mostly; 41 42 static LIST_HEAD(running_trace_list); 43 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock); 44 45 /* Select an alternative, minimalistic output than the original one */ 46 #define TRACE_BLK_OPT_CLASSIC 0x1 47 48 static struct tracer_opt blk_tracer_opts[] = { 49 /* Default disable the minimalistic output */ 50 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 51 { } 52 }; 53 54 static struct tracer_flags blk_tracer_flags = { 55 .val = 0, 56 .opts = blk_tracer_opts, 57 }; 58 59 /* Global reference count of probes */ 60 static atomic_t blk_probes_ref = ATOMIC_INIT(0); 61 62 static void blk_register_tracepoints(void); 63 static void blk_unregister_tracepoints(void); 64 65 /* 66 * Send out a notify message. 67 */ 68 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 69 const void *data, size_t len) 70 { 71 struct blk_io_trace *t; 72 struct ring_buffer_event *event = NULL; 73 struct ring_buffer *buffer = NULL; 74 int pc = 0; 75 int cpu = smp_processor_id(); 76 bool blk_tracer = blk_tracer_enabled; 77 78 if (blk_tracer) { 79 buffer = blk_tr->trace_buffer.buffer; 80 pc = preempt_count(); 81 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 82 sizeof(*t) + len, 83 0, pc); 84 if (!event) 85 return; 86 t = ring_buffer_event_data(event); 87 goto record_it; 88 } 89 90 if (!bt->rchan) 91 return; 92 93 t = relay_reserve(bt->rchan, sizeof(*t) + len); 94 if (t) { 95 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 96 t->time = ktime_to_ns(ktime_get()); 97 record_it: 98 t->device = bt->dev; 99 t->action = action; 100 t->pid = pid; 101 t->cpu = cpu; 102 t->pdu_len = len; 103 memcpy((void *) t + sizeof(*t), data, len); 104 105 if (blk_tracer) 106 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc); 107 } 108 } 109 110 /* 111 * Send out a notify for this process, if we haven't done so since a trace 112 * started 113 */ 114 static void trace_note_tsk(struct task_struct *tsk) 115 { 116 unsigned long flags; 117 struct blk_trace *bt; 118 119 tsk->btrace_seq = blktrace_seq; 120 spin_lock_irqsave(&running_trace_lock, flags); 121 list_for_each_entry(bt, &running_trace_list, running_list) { 122 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, 123 sizeof(tsk->comm)); 124 } 125 spin_unlock_irqrestore(&running_trace_lock, flags); 126 } 127 128 static void trace_note_time(struct blk_trace *bt) 129 { 130 struct timespec64 now; 131 unsigned long flags; 132 u32 words[2]; 133 134 /* need to check user space to see if this breaks in y2038 or y2106 */ 135 ktime_get_real_ts64(&now); 136 words[0] = (u32)now.tv_sec; 137 words[1] = now.tv_nsec; 138 139 local_irq_save(flags); 140 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); 141 local_irq_restore(flags); 142 } 143 144 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 145 { 146 int n; 147 va_list args; 148 unsigned long flags; 149 char *buf; 150 151 if (unlikely(bt->trace_state != Blktrace_running && 152 !blk_tracer_enabled)) 153 return; 154 155 /* 156 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note 157 * message to the trace. 158 */ 159 if (!(bt->act_mask & BLK_TC_NOTIFY)) 160 return; 161 162 local_irq_save(flags); 163 buf = this_cpu_ptr(bt->msg_data); 164 va_start(args, fmt); 165 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 166 va_end(args); 167 168 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); 169 local_irq_restore(flags); 170 } 171 EXPORT_SYMBOL_GPL(__trace_note_message); 172 173 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 174 pid_t pid) 175 { 176 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 177 return 1; 178 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 179 return 1; 180 if (bt->pid && pid != bt->pid) 181 return 1; 182 183 return 0; 184 } 185 186 /* 187 * Data direction bit lookup 188 */ 189 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 190 BLK_TC_ACT(BLK_TC_WRITE) }; 191 192 #define BLK_TC_RAHEAD BLK_TC_AHEAD 193 #define BLK_TC_PREFLUSH BLK_TC_FLUSH 194 195 /* The ilog2() calls fall out because they're constant */ 196 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \ 197 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name)) 198 199 /* 200 * The worker for the various blk_add_trace*() types. Fills out a 201 * blk_io_trace structure and places it in a per-cpu subbuffer. 202 */ 203 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 204 int op, int op_flags, u32 what, int error, int pdu_len, 205 void *pdu_data) 206 { 207 struct task_struct *tsk = current; 208 struct ring_buffer_event *event = NULL; 209 struct ring_buffer *buffer = NULL; 210 struct blk_io_trace *t; 211 unsigned long flags = 0; 212 unsigned long *sequence; 213 pid_t pid; 214 int cpu, pc = 0; 215 bool blk_tracer = blk_tracer_enabled; 216 217 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 218 return; 219 220 what |= ddir_act[op_is_write(op) ? WRITE : READ]; 221 what |= MASK_TC_BIT(op_flags, SYNC); 222 what |= MASK_TC_BIT(op_flags, RAHEAD); 223 what |= MASK_TC_BIT(op_flags, META); 224 what |= MASK_TC_BIT(op_flags, PREFLUSH); 225 what |= MASK_TC_BIT(op_flags, FUA); 226 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE) 227 what |= BLK_TC_ACT(BLK_TC_DISCARD); 228 if (op == REQ_OP_FLUSH) 229 what |= BLK_TC_ACT(BLK_TC_FLUSH); 230 231 pid = tsk->pid; 232 if (act_log_check(bt, what, sector, pid)) 233 return; 234 cpu = raw_smp_processor_id(); 235 236 if (blk_tracer) { 237 tracing_record_cmdline(current); 238 239 buffer = blk_tr->trace_buffer.buffer; 240 pc = preempt_count(); 241 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 242 sizeof(*t) + pdu_len, 243 0, pc); 244 if (!event) 245 return; 246 t = ring_buffer_event_data(event); 247 goto record_it; 248 } 249 250 if (unlikely(tsk->btrace_seq != blktrace_seq)) 251 trace_note_tsk(tsk); 252 253 /* 254 * A word about the locking here - we disable interrupts to reserve 255 * some space in the relay per-cpu buffer, to prevent an irq 256 * from coming in and stepping on our toes. 257 */ 258 local_irq_save(flags); 259 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); 260 if (t) { 261 sequence = per_cpu_ptr(bt->sequence, cpu); 262 263 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 264 t->sequence = ++(*sequence); 265 t->time = ktime_to_ns(ktime_get()); 266 record_it: 267 /* 268 * These two are not needed in ftrace as they are in the 269 * generic trace_entry, filled by tracing_generic_entry_update, 270 * but for the trace_event->bin() synthesizer benefit we do it 271 * here too. 272 */ 273 t->cpu = cpu; 274 t->pid = pid; 275 276 t->sector = sector; 277 t->bytes = bytes; 278 t->action = what; 279 t->device = bt->dev; 280 t->error = error; 281 t->pdu_len = pdu_len; 282 283 if (pdu_len) 284 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); 285 286 if (blk_tracer) { 287 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc); 288 return; 289 } 290 } 291 292 local_irq_restore(flags); 293 } 294 295 static struct dentry *blk_tree_root; 296 static DEFINE_MUTEX(blk_tree_mutex); 297 298 static void blk_trace_free(struct blk_trace *bt) 299 { 300 debugfs_remove(bt->msg_file); 301 debugfs_remove(bt->dropped_file); 302 relay_close(bt->rchan); 303 debugfs_remove(bt->dir); 304 free_percpu(bt->sequence); 305 free_percpu(bt->msg_data); 306 kfree(bt); 307 } 308 309 static void blk_trace_cleanup(struct blk_trace *bt) 310 { 311 blk_trace_free(bt); 312 if (atomic_dec_and_test(&blk_probes_ref)) 313 blk_unregister_tracepoints(); 314 } 315 316 int blk_trace_remove(struct request_queue *q) 317 { 318 struct blk_trace *bt; 319 320 bt = xchg(&q->blk_trace, NULL); 321 if (!bt) 322 return -EINVAL; 323 324 if (bt->trace_state != Blktrace_running) 325 blk_trace_cleanup(bt); 326 327 return 0; 328 } 329 EXPORT_SYMBOL_GPL(blk_trace_remove); 330 331 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 332 size_t count, loff_t *ppos) 333 { 334 struct blk_trace *bt = filp->private_data; 335 char buf[16]; 336 337 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 338 339 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 340 } 341 342 static const struct file_operations blk_dropped_fops = { 343 .owner = THIS_MODULE, 344 .open = simple_open, 345 .read = blk_dropped_read, 346 .llseek = default_llseek, 347 }; 348 349 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 350 size_t count, loff_t *ppos) 351 { 352 char *msg; 353 struct blk_trace *bt; 354 355 if (count >= BLK_TN_MAX_MSG) 356 return -EINVAL; 357 358 msg = memdup_user_nul(buffer, count); 359 if (IS_ERR(msg)) 360 return PTR_ERR(msg); 361 362 bt = filp->private_data; 363 __trace_note_message(bt, "%s", msg); 364 kfree(msg); 365 366 return count; 367 } 368 369 static const struct file_operations blk_msg_fops = { 370 .owner = THIS_MODULE, 371 .open = simple_open, 372 .write = blk_msg_write, 373 .llseek = noop_llseek, 374 }; 375 376 /* 377 * Keep track of how many times we encountered a full subbuffer, to aid 378 * the user space app in telling how many lost events there were. 379 */ 380 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 381 void *prev_subbuf, size_t prev_padding) 382 { 383 struct blk_trace *bt; 384 385 if (!relay_buf_full(buf)) 386 return 1; 387 388 bt = buf->chan->private_data; 389 atomic_inc(&bt->dropped); 390 return 0; 391 } 392 393 static int blk_remove_buf_file_callback(struct dentry *dentry) 394 { 395 debugfs_remove(dentry); 396 397 return 0; 398 } 399 400 static struct dentry *blk_create_buf_file_callback(const char *filename, 401 struct dentry *parent, 402 umode_t mode, 403 struct rchan_buf *buf, 404 int *is_global) 405 { 406 return debugfs_create_file(filename, mode, parent, buf, 407 &relay_file_operations); 408 } 409 410 static struct rchan_callbacks blk_relay_callbacks = { 411 .subbuf_start = blk_subbuf_start_callback, 412 .create_buf_file = blk_create_buf_file_callback, 413 .remove_buf_file = blk_remove_buf_file_callback, 414 }; 415 416 static void blk_trace_setup_lba(struct blk_trace *bt, 417 struct block_device *bdev) 418 { 419 struct hd_struct *part = NULL; 420 421 if (bdev) 422 part = bdev->bd_part; 423 424 if (part) { 425 bt->start_lba = part->start_sect; 426 bt->end_lba = part->start_sect + part->nr_sects; 427 } else { 428 bt->start_lba = 0; 429 bt->end_lba = -1ULL; 430 } 431 } 432 433 /* 434 * Setup everything required to start tracing 435 */ 436 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 437 struct block_device *bdev, 438 struct blk_user_trace_setup *buts) 439 { 440 struct blk_trace *bt = NULL; 441 struct dentry *dir = NULL; 442 int ret; 443 444 if (!buts->buf_size || !buts->buf_nr) 445 return -EINVAL; 446 447 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 448 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 449 450 /* 451 * some device names have larger paths - convert the slashes 452 * to underscores for this to work as expected 453 */ 454 strreplace(buts->name, '/', '_'); 455 456 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 457 if (!bt) 458 return -ENOMEM; 459 460 ret = -ENOMEM; 461 bt->sequence = alloc_percpu(unsigned long); 462 if (!bt->sequence) 463 goto err; 464 465 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 466 if (!bt->msg_data) 467 goto err; 468 469 ret = -ENOENT; 470 471 mutex_lock(&blk_tree_mutex); 472 if (!blk_tree_root) { 473 blk_tree_root = debugfs_create_dir("block", NULL); 474 if (!blk_tree_root) { 475 mutex_unlock(&blk_tree_mutex); 476 goto err; 477 } 478 } 479 mutex_unlock(&blk_tree_mutex); 480 481 dir = debugfs_create_dir(buts->name, blk_tree_root); 482 483 if (!dir) 484 goto err; 485 486 bt->dir = dir; 487 bt->dev = dev; 488 atomic_set(&bt->dropped, 0); 489 INIT_LIST_HEAD(&bt->running_list); 490 491 ret = -EIO; 492 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 493 &blk_dropped_fops); 494 if (!bt->dropped_file) 495 goto err; 496 497 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 498 if (!bt->msg_file) 499 goto err; 500 501 bt->rchan = relay_open("trace", dir, buts->buf_size, 502 buts->buf_nr, &blk_relay_callbacks, bt); 503 if (!bt->rchan) 504 goto err; 505 506 bt->act_mask = buts->act_mask; 507 if (!bt->act_mask) 508 bt->act_mask = (u16) -1; 509 510 blk_trace_setup_lba(bt, bdev); 511 512 /* overwrite with user settings */ 513 if (buts->start_lba) 514 bt->start_lba = buts->start_lba; 515 if (buts->end_lba) 516 bt->end_lba = buts->end_lba; 517 518 bt->pid = buts->pid; 519 bt->trace_state = Blktrace_setup; 520 521 ret = -EBUSY; 522 if (cmpxchg(&q->blk_trace, NULL, bt)) 523 goto err; 524 525 if (atomic_inc_return(&blk_probes_ref) == 1) 526 blk_register_tracepoints(); 527 528 return 0; 529 err: 530 blk_trace_free(bt); 531 return ret; 532 } 533 534 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 535 struct block_device *bdev, 536 char __user *arg) 537 { 538 struct blk_user_trace_setup buts; 539 int ret; 540 541 ret = copy_from_user(&buts, arg, sizeof(buts)); 542 if (ret) 543 return -EFAULT; 544 545 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 546 if (ret) 547 return ret; 548 549 if (copy_to_user(arg, &buts, sizeof(buts))) { 550 blk_trace_remove(q); 551 return -EFAULT; 552 } 553 return 0; 554 } 555 EXPORT_SYMBOL_GPL(blk_trace_setup); 556 557 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 558 static int compat_blk_trace_setup(struct request_queue *q, char *name, 559 dev_t dev, struct block_device *bdev, 560 char __user *arg) 561 { 562 struct blk_user_trace_setup buts; 563 struct compat_blk_user_trace_setup cbuts; 564 int ret; 565 566 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 567 return -EFAULT; 568 569 buts = (struct blk_user_trace_setup) { 570 .act_mask = cbuts.act_mask, 571 .buf_size = cbuts.buf_size, 572 .buf_nr = cbuts.buf_nr, 573 .start_lba = cbuts.start_lba, 574 .end_lba = cbuts.end_lba, 575 .pid = cbuts.pid, 576 }; 577 578 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 579 if (ret) 580 return ret; 581 582 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) { 583 blk_trace_remove(q); 584 return -EFAULT; 585 } 586 587 return 0; 588 } 589 #endif 590 591 int blk_trace_startstop(struct request_queue *q, int start) 592 { 593 int ret; 594 struct blk_trace *bt = q->blk_trace; 595 596 if (bt == NULL) 597 return -EINVAL; 598 599 /* 600 * For starting a trace, we can transition from a setup or stopped 601 * trace. For stopping a trace, the state must be running 602 */ 603 ret = -EINVAL; 604 if (start) { 605 if (bt->trace_state == Blktrace_setup || 606 bt->trace_state == Blktrace_stopped) { 607 blktrace_seq++; 608 smp_mb(); 609 bt->trace_state = Blktrace_running; 610 spin_lock_irq(&running_trace_lock); 611 list_add(&bt->running_list, &running_trace_list); 612 spin_unlock_irq(&running_trace_lock); 613 614 trace_note_time(bt); 615 ret = 0; 616 } 617 } else { 618 if (bt->trace_state == Blktrace_running) { 619 bt->trace_state = Blktrace_stopped; 620 spin_lock_irq(&running_trace_lock); 621 list_del_init(&bt->running_list); 622 spin_unlock_irq(&running_trace_lock); 623 relay_flush(bt->rchan); 624 ret = 0; 625 } 626 } 627 628 return ret; 629 } 630 EXPORT_SYMBOL_GPL(blk_trace_startstop); 631 632 /** 633 * blk_trace_ioctl: - handle the ioctls associated with tracing 634 * @bdev: the block device 635 * @cmd: the ioctl cmd 636 * @arg: the argument data, if any 637 * 638 **/ 639 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 640 { 641 struct request_queue *q; 642 int ret, start = 0; 643 char b[BDEVNAME_SIZE]; 644 645 q = bdev_get_queue(bdev); 646 if (!q) 647 return -ENXIO; 648 649 mutex_lock(&bdev->bd_mutex); 650 651 switch (cmd) { 652 case BLKTRACESETUP: 653 bdevname(bdev, b); 654 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 655 break; 656 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 657 case BLKTRACESETUP32: 658 bdevname(bdev, b); 659 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 660 break; 661 #endif 662 case BLKTRACESTART: 663 start = 1; 664 case BLKTRACESTOP: 665 ret = blk_trace_startstop(q, start); 666 break; 667 case BLKTRACETEARDOWN: 668 ret = blk_trace_remove(q); 669 break; 670 default: 671 ret = -ENOTTY; 672 break; 673 } 674 675 mutex_unlock(&bdev->bd_mutex); 676 return ret; 677 } 678 679 /** 680 * blk_trace_shutdown: - stop and cleanup trace structures 681 * @q: the request queue associated with the device 682 * 683 **/ 684 void blk_trace_shutdown(struct request_queue *q) 685 { 686 if (q->blk_trace) { 687 blk_trace_startstop(q, 0); 688 blk_trace_remove(q); 689 } 690 } 691 692 /* 693 * blktrace probes 694 */ 695 696 /** 697 * blk_add_trace_rq - Add a trace for a request oriented action 698 * @q: queue the io is for 699 * @rq: the source request 700 * @nr_bytes: number of completed bytes 701 * @what: the action 702 * 703 * Description: 704 * Records an action against a request. Will log the bio offset + size. 705 * 706 **/ 707 static void blk_add_trace_rq(struct request_queue *q, struct request *rq, 708 unsigned int nr_bytes, u32 what) 709 { 710 struct blk_trace *bt = q->blk_trace; 711 712 if (likely(!bt)) 713 return; 714 715 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { 716 what |= BLK_TC_ACT(BLK_TC_PC); 717 __blk_add_trace(bt, 0, nr_bytes, req_op(rq), rq->cmd_flags, 718 what, rq->errors, rq->cmd_len, rq->cmd); 719 } else { 720 what |= BLK_TC_ACT(BLK_TC_FS); 721 __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes, req_op(rq), 722 rq->cmd_flags, what, rq->errors, 0, NULL); 723 } 724 } 725 726 static void blk_add_trace_rq_abort(void *ignore, 727 struct request_queue *q, struct request *rq) 728 { 729 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT); 730 } 731 732 static void blk_add_trace_rq_insert(void *ignore, 733 struct request_queue *q, struct request *rq) 734 { 735 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT); 736 } 737 738 static void blk_add_trace_rq_issue(void *ignore, 739 struct request_queue *q, struct request *rq) 740 { 741 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE); 742 } 743 744 static void blk_add_trace_rq_requeue(void *ignore, 745 struct request_queue *q, 746 struct request *rq) 747 { 748 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE); 749 } 750 751 static void blk_add_trace_rq_complete(void *ignore, 752 struct request_queue *q, 753 struct request *rq, 754 unsigned int nr_bytes) 755 { 756 blk_add_trace_rq(q, rq, nr_bytes, 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 * @error: error, if any 765 * 766 * Description: 767 * Records an action against a bio. Will log the bio offset + size. 768 * 769 **/ 770 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 771 u32 what, int error) 772 { 773 struct blk_trace *bt = q->blk_trace; 774 775 if (likely(!bt)) 776 return; 777 778 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 779 bio_op(bio), bio->bi_opf, what, error, 0, NULL); 780 } 781 782 static void blk_add_trace_bio_bounce(void *ignore, 783 struct request_queue *q, struct bio *bio) 784 { 785 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0); 786 } 787 788 static void blk_add_trace_bio_complete(void *ignore, 789 struct request_queue *q, struct bio *bio, 790 int error) 791 { 792 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error); 793 } 794 795 static void blk_add_trace_bio_backmerge(void *ignore, 796 struct request_queue *q, 797 struct request *rq, 798 struct bio *bio) 799 { 800 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0); 801 } 802 803 static void blk_add_trace_bio_frontmerge(void *ignore, 804 struct request_queue *q, 805 struct request *rq, 806 struct bio *bio) 807 { 808 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0); 809 } 810 811 static void blk_add_trace_bio_queue(void *ignore, 812 struct request_queue *q, struct bio *bio) 813 { 814 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0); 815 } 816 817 static void blk_add_trace_getrq(void *ignore, 818 struct request_queue *q, 819 struct bio *bio, int rw) 820 { 821 if (bio) 822 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0); 823 else { 824 struct blk_trace *bt = q->blk_trace; 825 826 if (bt) 827 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0, 828 NULL); 829 } 830 } 831 832 833 static void blk_add_trace_sleeprq(void *ignore, 834 struct request_queue *q, 835 struct bio *bio, int rw) 836 { 837 if (bio) 838 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0); 839 else { 840 struct blk_trace *bt = q->blk_trace; 841 842 if (bt) 843 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ, 844 0, 0, NULL); 845 } 846 } 847 848 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 849 { 850 struct blk_trace *bt = q->blk_trace; 851 852 if (bt) 853 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); 854 } 855 856 static void blk_add_trace_unplug(void *ignore, struct request_queue *q, 857 unsigned int depth, bool explicit) 858 { 859 struct blk_trace *bt = q->blk_trace; 860 861 if (bt) { 862 __be64 rpdu = cpu_to_be64(depth); 863 u32 what; 864 865 if (explicit) 866 what = BLK_TA_UNPLUG_IO; 867 else 868 what = BLK_TA_UNPLUG_TIMER; 869 870 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu); 871 } 872 } 873 874 static void blk_add_trace_split(void *ignore, 875 struct request_queue *q, struct bio *bio, 876 unsigned int pdu) 877 { 878 struct blk_trace *bt = q->blk_trace; 879 880 if (bt) { 881 __be64 rpdu = cpu_to_be64(pdu); 882 883 __blk_add_trace(bt, bio->bi_iter.bi_sector, 884 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf, 885 BLK_TA_SPLIT, bio->bi_error, sizeof(rpdu), 886 &rpdu); 887 } 888 } 889 890 /** 891 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation 892 * @ignore: trace callback data parameter (not used) 893 * @q: queue the io is for 894 * @bio: the source bio 895 * @dev: target device 896 * @from: source sector 897 * 898 * Description: 899 * Device mapper or raid target sometimes need to split a bio because 900 * it spans a stripe (or similar). Add a trace for that action. 901 * 902 **/ 903 static void blk_add_trace_bio_remap(void *ignore, 904 struct request_queue *q, struct bio *bio, 905 dev_t dev, sector_t from) 906 { 907 struct blk_trace *bt = q->blk_trace; 908 struct blk_io_trace_remap r; 909 910 if (likely(!bt)) 911 return; 912 913 r.device_from = cpu_to_be32(dev); 914 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); 915 r.sector_from = cpu_to_be64(from); 916 917 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 918 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_error, 919 sizeof(r), &r); 920 } 921 922 /** 923 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 924 * @ignore: trace callback data parameter (not used) 925 * @q: queue the io is for 926 * @rq: the source request 927 * @dev: target device 928 * @from: source sector 929 * 930 * Description: 931 * Device mapper remaps request to other devices. 932 * Add a trace for that action. 933 * 934 **/ 935 static void blk_add_trace_rq_remap(void *ignore, 936 struct request_queue *q, 937 struct request *rq, dev_t dev, 938 sector_t from) 939 { 940 struct blk_trace *bt = q->blk_trace; 941 struct blk_io_trace_remap r; 942 943 if (likely(!bt)) 944 return; 945 946 r.device_from = cpu_to_be32(dev); 947 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 948 r.sector_from = cpu_to_be64(from); 949 950 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 951 rq_data_dir(rq), 0, BLK_TA_REMAP, !!rq->errors, 952 sizeof(r), &r); 953 } 954 955 /** 956 * blk_add_driver_data - Add binary message with driver-specific data 957 * @q: queue the io is for 958 * @rq: io request 959 * @data: driver-specific data 960 * @len: length of driver-specific data 961 * 962 * Description: 963 * Some drivers might want to write driver-specific data per request. 964 * 965 **/ 966 void blk_add_driver_data(struct request_queue *q, 967 struct request *rq, 968 void *data, size_t len) 969 { 970 struct blk_trace *bt = q->blk_trace; 971 972 if (likely(!bt)) 973 return; 974 975 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) 976 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 0, 977 BLK_TA_DRV_DATA, rq->errors, len, data); 978 else 979 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 0, 980 BLK_TA_DRV_DATA, rq->errors, len, data); 981 } 982 EXPORT_SYMBOL_GPL(blk_add_driver_data); 983 984 static void blk_register_tracepoints(void) 985 { 986 int ret; 987 988 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 989 WARN_ON(ret); 990 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 991 WARN_ON(ret); 992 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 993 WARN_ON(ret); 994 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 995 WARN_ON(ret); 996 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 997 WARN_ON(ret); 998 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 999 WARN_ON(ret); 1000 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1001 WARN_ON(ret); 1002 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1003 WARN_ON(ret); 1004 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1005 WARN_ON(ret); 1006 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1007 WARN_ON(ret); 1008 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 1009 WARN_ON(ret); 1010 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1011 WARN_ON(ret); 1012 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 1013 WARN_ON(ret); 1014 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL); 1015 WARN_ON(ret); 1016 ret = register_trace_block_split(blk_add_trace_split, NULL); 1017 WARN_ON(ret); 1018 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1019 WARN_ON(ret); 1020 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1021 WARN_ON(ret); 1022 } 1023 1024 static void blk_unregister_tracepoints(void) 1025 { 1026 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1027 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1028 unregister_trace_block_split(blk_add_trace_split, NULL); 1029 unregister_trace_block_unplug(blk_add_trace_unplug, NULL); 1030 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1031 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1032 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1033 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1034 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1035 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1036 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1037 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1038 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1039 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1040 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1041 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1042 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL); 1043 1044 tracepoint_synchronize_unregister(); 1045 } 1046 1047 /* 1048 * struct blk_io_tracer formatting routines 1049 */ 1050 1051 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1052 { 1053 int i = 0; 1054 int tc = t->action >> BLK_TC_SHIFT; 1055 1056 if (t->action == BLK_TN_MESSAGE) { 1057 rwbs[i++] = 'N'; 1058 goto out; 1059 } 1060 1061 if (tc & BLK_TC_FLUSH) 1062 rwbs[i++] = 'F'; 1063 1064 if (tc & BLK_TC_DISCARD) 1065 rwbs[i++] = 'D'; 1066 else if (tc & BLK_TC_WRITE) 1067 rwbs[i++] = 'W'; 1068 else if (t->bytes) 1069 rwbs[i++] = 'R'; 1070 else 1071 rwbs[i++] = 'N'; 1072 1073 if (tc & BLK_TC_FUA) 1074 rwbs[i++] = 'F'; 1075 if (tc & BLK_TC_AHEAD) 1076 rwbs[i++] = 'A'; 1077 if (tc & BLK_TC_SYNC) 1078 rwbs[i++] = 'S'; 1079 if (tc & BLK_TC_META) 1080 rwbs[i++] = 'M'; 1081 out: 1082 rwbs[i] = '\0'; 1083 } 1084 1085 static inline 1086 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1087 { 1088 return (const struct blk_io_trace *)ent; 1089 } 1090 1091 static inline const void *pdu_start(const struct trace_entry *ent) 1092 { 1093 return te_blk_io_trace(ent) + 1; 1094 } 1095 1096 static inline u32 t_action(const struct trace_entry *ent) 1097 { 1098 return te_blk_io_trace(ent)->action; 1099 } 1100 1101 static inline u32 t_bytes(const struct trace_entry *ent) 1102 { 1103 return te_blk_io_trace(ent)->bytes; 1104 } 1105 1106 static inline u32 t_sec(const struct trace_entry *ent) 1107 { 1108 return te_blk_io_trace(ent)->bytes >> 9; 1109 } 1110 1111 static inline unsigned long long t_sector(const struct trace_entry *ent) 1112 { 1113 return te_blk_io_trace(ent)->sector; 1114 } 1115 1116 static inline __u16 t_error(const struct trace_entry *ent) 1117 { 1118 return te_blk_io_trace(ent)->error; 1119 } 1120 1121 static __u64 get_pdu_int(const struct trace_entry *ent) 1122 { 1123 const __u64 *val = pdu_start(ent); 1124 return be64_to_cpu(*val); 1125 } 1126 1127 static void get_pdu_remap(const struct trace_entry *ent, 1128 struct blk_io_trace_remap *r) 1129 { 1130 const struct blk_io_trace_remap *__r = pdu_start(ent); 1131 __u64 sector_from = __r->sector_from; 1132 1133 r->device_from = be32_to_cpu(__r->device_from); 1134 r->device_to = be32_to_cpu(__r->device_to); 1135 r->sector_from = be64_to_cpu(sector_from); 1136 } 1137 1138 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act); 1139 1140 static void blk_log_action_classic(struct trace_iterator *iter, const char *act) 1141 { 1142 char rwbs[RWBS_LEN]; 1143 unsigned long long ts = iter->ts; 1144 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1145 unsigned secs = (unsigned long)ts; 1146 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1147 1148 fill_rwbs(rwbs, t); 1149 1150 trace_seq_printf(&iter->seq, 1151 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1152 MAJOR(t->device), MINOR(t->device), iter->cpu, 1153 secs, nsec_rem, iter->ent->pid, act, rwbs); 1154 } 1155 1156 static void blk_log_action(struct trace_iterator *iter, const char *act) 1157 { 1158 char rwbs[RWBS_LEN]; 1159 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1160 1161 fill_rwbs(rwbs, t); 1162 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1163 MAJOR(t->device), MINOR(t->device), act, rwbs); 1164 } 1165 1166 static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) 1167 { 1168 const unsigned char *pdu_buf; 1169 int pdu_len; 1170 int i, end; 1171 1172 pdu_buf = pdu_start(ent); 1173 pdu_len = te_blk_io_trace(ent)->pdu_len; 1174 1175 if (!pdu_len) 1176 return; 1177 1178 /* find the last zero that needs to be printed */ 1179 for (end = pdu_len - 1; end >= 0; end--) 1180 if (pdu_buf[end]) 1181 break; 1182 end++; 1183 1184 trace_seq_putc(s, '('); 1185 1186 for (i = 0; i < pdu_len; i++) { 1187 1188 trace_seq_printf(s, "%s%02x", 1189 i == 0 ? "" : " ", pdu_buf[i]); 1190 1191 /* 1192 * stop when the rest is just zeroes and indicate so 1193 * with a ".." appended 1194 */ 1195 if (i == end && end != pdu_len - 1) { 1196 trace_seq_puts(s, " ..) "); 1197 return; 1198 } 1199 } 1200 1201 trace_seq_puts(s, ") "); 1202 } 1203 1204 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) 1205 { 1206 char cmd[TASK_COMM_LEN]; 1207 1208 trace_find_cmdline(ent->pid, cmd); 1209 1210 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1211 trace_seq_printf(s, "%u ", t_bytes(ent)); 1212 blk_log_dump_pdu(s, ent); 1213 trace_seq_printf(s, "[%s]\n", cmd); 1214 } else { 1215 if (t_sec(ent)) 1216 trace_seq_printf(s, "%llu + %u [%s]\n", 1217 t_sector(ent), t_sec(ent), cmd); 1218 else 1219 trace_seq_printf(s, "[%s]\n", cmd); 1220 } 1221 } 1222 1223 static void blk_log_with_error(struct trace_seq *s, 1224 const struct trace_entry *ent) 1225 { 1226 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1227 blk_log_dump_pdu(s, ent); 1228 trace_seq_printf(s, "[%d]\n", t_error(ent)); 1229 } else { 1230 if (t_sec(ent)) 1231 trace_seq_printf(s, "%llu + %u [%d]\n", 1232 t_sector(ent), 1233 t_sec(ent), t_error(ent)); 1234 else 1235 trace_seq_printf(s, "%llu [%d]\n", 1236 t_sector(ent), t_error(ent)); 1237 } 1238 } 1239 1240 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) 1241 { 1242 struct blk_io_trace_remap r = { .device_from = 0, }; 1243 1244 get_pdu_remap(ent, &r); 1245 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1246 t_sector(ent), t_sec(ent), 1247 MAJOR(r.device_from), MINOR(r.device_from), 1248 (unsigned long long)r.sector_from); 1249 } 1250 1251 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) 1252 { 1253 char cmd[TASK_COMM_LEN]; 1254 1255 trace_find_cmdline(ent->pid, cmd); 1256 1257 trace_seq_printf(s, "[%s]\n", cmd); 1258 } 1259 1260 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) 1261 { 1262 char cmd[TASK_COMM_LEN]; 1263 1264 trace_find_cmdline(ent->pid, cmd); 1265 1266 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); 1267 } 1268 1269 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 1270 { 1271 char cmd[TASK_COMM_LEN]; 1272 1273 trace_find_cmdline(ent->pid, cmd); 1274 1275 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1276 get_pdu_int(ent), cmd); 1277 } 1278 1279 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) 1280 { 1281 const struct blk_io_trace *t = te_blk_io_trace(ent); 1282 1283 trace_seq_putmem(s, t + 1, t->pdu_len); 1284 trace_seq_putc(s, '\n'); 1285 } 1286 1287 /* 1288 * struct tracer operations 1289 */ 1290 1291 static void blk_tracer_print_header(struct seq_file *m) 1292 { 1293 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1294 return; 1295 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1296 "# | | | | | |\n"); 1297 } 1298 1299 static void blk_tracer_start(struct trace_array *tr) 1300 { 1301 blk_tracer_enabled = true; 1302 } 1303 1304 static int blk_tracer_init(struct trace_array *tr) 1305 { 1306 blk_tr = tr; 1307 blk_tracer_start(tr); 1308 return 0; 1309 } 1310 1311 static void blk_tracer_stop(struct trace_array *tr) 1312 { 1313 blk_tracer_enabled = false; 1314 } 1315 1316 static void blk_tracer_reset(struct trace_array *tr) 1317 { 1318 blk_tracer_stop(tr); 1319 } 1320 1321 static const struct { 1322 const char *act[2]; 1323 void (*print)(struct trace_seq *s, const struct trace_entry *ent); 1324 } what2act[] = { 1325 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1326 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1327 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1328 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1329 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1330 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1331 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1332 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1333 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1334 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1335 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1336 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1337 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1338 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1339 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1340 }; 1341 1342 static enum print_line_t print_one_line(struct trace_iterator *iter, 1343 bool classic) 1344 { 1345 struct trace_array *tr = iter->tr; 1346 struct trace_seq *s = &iter->seq; 1347 const struct blk_io_trace *t; 1348 u16 what; 1349 bool long_act; 1350 blk_log_action_t *log_action; 1351 1352 t = te_blk_io_trace(iter->ent); 1353 what = t->action & ((1 << BLK_TC_SHIFT) - 1); 1354 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE); 1355 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1356 1357 if (t->action == BLK_TN_MESSAGE) { 1358 log_action(iter, long_act ? "message" : "m"); 1359 blk_log_msg(s, iter->ent); 1360 return trace_handle_return(s); 1361 } 1362 1363 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1364 trace_seq_printf(s, "Unknown action %x\n", what); 1365 else { 1366 log_action(iter, what2act[what].act[long_act]); 1367 what2act[what].print(s, iter->ent); 1368 } 1369 1370 return trace_handle_return(s); 1371 } 1372 1373 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1374 int flags, struct trace_event *event) 1375 { 1376 return print_one_line(iter, false); 1377 } 1378 1379 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1380 { 1381 struct trace_seq *s = &iter->seq; 1382 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1383 const int offset = offsetof(struct blk_io_trace, sector); 1384 struct blk_io_trace old = { 1385 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1386 .time = iter->ts, 1387 }; 1388 1389 trace_seq_putmem(s, &old, offset); 1390 trace_seq_putmem(s, &t->sector, 1391 sizeof(old) - offset + t->pdu_len); 1392 } 1393 1394 static enum print_line_t 1395 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1396 struct trace_event *event) 1397 { 1398 blk_trace_synthesize_old_trace(iter); 1399 1400 return trace_handle_return(&iter->seq); 1401 } 1402 1403 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1404 { 1405 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1406 return TRACE_TYPE_UNHANDLED; 1407 1408 return print_one_line(iter, true); 1409 } 1410 1411 static int 1412 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) 1413 { 1414 /* don't output context-info for blk_classic output */ 1415 if (bit == TRACE_BLK_OPT_CLASSIC) { 1416 if (set) 1417 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1418 else 1419 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO; 1420 } 1421 return 0; 1422 } 1423 1424 static struct tracer blk_tracer __read_mostly = { 1425 .name = "blk", 1426 .init = blk_tracer_init, 1427 .reset = blk_tracer_reset, 1428 .start = blk_tracer_start, 1429 .stop = blk_tracer_stop, 1430 .print_header = blk_tracer_print_header, 1431 .print_line = blk_tracer_print_line, 1432 .flags = &blk_tracer_flags, 1433 .set_flag = blk_tracer_set_flag, 1434 }; 1435 1436 static struct trace_event_functions trace_blk_event_funcs = { 1437 .trace = blk_trace_event_print, 1438 .binary = blk_trace_event_print_binary, 1439 }; 1440 1441 static struct trace_event trace_blk_event = { 1442 .type = TRACE_BLK, 1443 .funcs = &trace_blk_event_funcs, 1444 }; 1445 1446 static int __init init_blk_tracer(void) 1447 { 1448 if (!register_trace_event(&trace_blk_event)) { 1449 pr_warn("Warning: could not register block events\n"); 1450 return 1; 1451 } 1452 1453 if (register_tracer(&blk_tracer) != 0) { 1454 pr_warn("Warning: could not register the block tracer\n"); 1455 unregister_trace_event(&trace_blk_event); 1456 return 1; 1457 } 1458 1459 return 0; 1460 } 1461 1462 device_initcall(init_blk_tracer); 1463 1464 static int blk_trace_remove_queue(struct request_queue *q) 1465 { 1466 struct blk_trace *bt; 1467 1468 bt = xchg(&q->blk_trace, NULL); 1469 if (bt == NULL) 1470 return -EINVAL; 1471 1472 if (atomic_dec_and_test(&blk_probes_ref)) 1473 blk_unregister_tracepoints(); 1474 1475 blk_trace_free(bt); 1476 return 0; 1477 } 1478 1479 /* 1480 * Setup everything required to start tracing 1481 */ 1482 static int blk_trace_setup_queue(struct request_queue *q, 1483 struct block_device *bdev) 1484 { 1485 struct blk_trace *bt = NULL; 1486 int ret = -ENOMEM; 1487 1488 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1489 if (!bt) 1490 return -ENOMEM; 1491 1492 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1493 if (!bt->msg_data) 1494 goto free_bt; 1495 1496 bt->dev = bdev->bd_dev; 1497 bt->act_mask = (u16)-1; 1498 1499 blk_trace_setup_lba(bt, bdev); 1500 1501 ret = -EBUSY; 1502 if (cmpxchg(&q->blk_trace, NULL, bt)) 1503 goto free_bt; 1504 1505 if (atomic_inc_return(&blk_probes_ref) == 1) 1506 blk_register_tracepoints(); 1507 return 0; 1508 1509 free_bt: 1510 blk_trace_free(bt); 1511 return ret; 1512 } 1513 1514 /* 1515 * sysfs interface to enable and configure tracing 1516 */ 1517 1518 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1519 struct device_attribute *attr, 1520 char *buf); 1521 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1522 struct device_attribute *attr, 1523 const char *buf, size_t count); 1524 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1525 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1526 sysfs_blk_trace_attr_show, \ 1527 sysfs_blk_trace_attr_store) 1528 1529 static BLK_TRACE_DEVICE_ATTR(enable); 1530 static BLK_TRACE_DEVICE_ATTR(act_mask); 1531 static BLK_TRACE_DEVICE_ATTR(pid); 1532 static BLK_TRACE_DEVICE_ATTR(start_lba); 1533 static BLK_TRACE_DEVICE_ATTR(end_lba); 1534 1535 static struct attribute *blk_trace_attrs[] = { 1536 &dev_attr_enable.attr, 1537 &dev_attr_act_mask.attr, 1538 &dev_attr_pid.attr, 1539 &dev_attr_start_lba.attr, 1540 &dev_attr_end_lba.attr, 1541 NULL 1542 }; 1543 1544 struct attribute_group blk_trace_attr_group = { 1545 .name = "trace", 1546 .attrs = blk_trace_attrs, 1547 }; 1548 1549 static const struct { 1550 int mask; 1551 const char *str; 1552 } mask_maps[] = { 1553 { BLK_TC_READ, "read" }, 1554 { BLK_TC_WRITE, "write" }, 1555 { BLK_TC_FLUSH, "flush" }, 1556 { BLK_TC_SYNC, "sync" }, 1557 { BLK_TC_QUEUE, "queue" }, 1558 { BLK_TC_REQUEUE, "requeue" }, 1559 { BLK_TC_ISSUE, "issue" }, 1560 { BLK_TC_COMPLETE, "complete" }, 1561 { BLK_TC_FS, "fs" }, 1562 { BLK_TC_PC, "pc" }, 1563 { BLK_TC_NOTIFY, "notify" }, 1564 { BLK_TC_AHEAD, "ahead" }, 1565 { BLK_TC_META, "meta" }, 1566 { BLK_TC_DISCARD, "discard" }, 1567 { BLK_TC_DRV_DATA, "drv_data" }, 1568 { BLK_TC_FUA, "fua" }, 1569 }; 1570 1571 static int blk_trace_str2mask(const char *str) 1572 { 1573 int i; 1574 int mask = 0; 1575 char *buf, *s, *token; 1576 1577 buf = kstrdup(str, GFP_KERNEL); 1578 if (buf == NULL) 1579 return -ENOMEM; 1580 s = strstrip(buf); 1581 1582 while (1) { 1583 token = strsep(&s, ","); 1584 if (token == NULL) 1585 break; 1586 1587 if (*token == '\0') 1588 continue; 1589 1590 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1591 if (strcasecmp(token, mask_maps[i].str) == 0) { 1592 mask |= mask_maps[i].mask; 1593 break; 1594 } 1595 } 1596 if (i == ARRAY_SIZE(mask_maps)) { 1597 mask = -EINVAL; 1598 break; 1599 } 1600 } 1601 kfree(buf); 1602 1603 return mask; 1604 } 1605 1606 static ssize_t blk_trace_mask2str(char *buf, int mask) 1607 { 1608 int i; 1609 char *p = buf; 1610 1611 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1612 if (mask & mask_maps[i].mask) { 1613 p += sprintf(p, "%s%s", 1614 (p == buf) ? "" : ",", mask_maps[i].str); 1615 } 1616 } 1617 *p++ = '\n'; 1618 1619 return p - buf; 1620 } 1621 1622 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1623 { 1624 if (bdev->bd_disk == NULL) 1625 return NULL; 1626 1627 return bdev_get_queue(bdev); 1628 } 1629 1630 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1631 struct device_attribute *attr, 1632 char *buf) 1633 { 1634 struct hd_struct *p = dev_to_part(dev); 1635 struct request_queue *q; 1636 struct block_device *bdev; 1637 ssize_t ret = -ENXIO; 1638 1639 bdev = bdget(part_devt(p)); 1640 if (bdev == NULL) 1641 goto out; 1642 1643 q = blk_trace_get_queue(bdev); 1644 if (q == NULL) 1645 goto out_bdput; 1646 1647 mutex_lock(&bdev->bd_mutex); 1648 1649 if (attr == &dev_attr_enable) { 1650 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1651 goto out_unlock_bdev; 1652 } 1653 1654 if (q->blk_trace == NULL) 1655 ret = sprintf(buf, "disabled\n"); 1656 else if (attr == &dev_attr_act_mask) 1657 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1658 else if (attr == &dev_attr_pid) 1659 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1660 else if (attr == &dev_attr_start_lba) 1661 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1662 else if (attr == &dev_attr_end_lba) 1663 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1664 1665 out_unlock_bdev: 1666 mutex_unlock(&bdev->bd_mutex); 1667 out_bdput: 1668 bdput(bdev); 1669 out: 1670 return ret; 1671 } 1672 1673 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1674 struct device_attribute *attr, 1675 const char *buf, size_t count) 1676 { 1677 struct block_device *bdev; 1678 struct request_queue *q; 1679 struct hd_struct *p; 1680 u64 value; 1681 ssize_t ret = -EINVAL; 1682 1683 if (count == 0) 1684 goto out; 1685 1686 if (attr == &dev_attr_act_mask) { 1687 if (sscanf(buf, "%llx", &value) != 1) { 1688 /* Assume it is a list of trace category names */ 1689 ret = blk_trace_str2mask(buf); 1690 if (ret < 0) 1691 goto out; 1692 value = ret; 1693 } 1694 } else if (sscanf(buf, "%llu", &value) != 1) 1695 goto out; 1696 1697 ret = -ENXIO; 1698 1699 p = dev_to_part(dev); 1700 bdev = bdget(part_devt(p)); 1701 if (bdev == NULL) 1702 goto out; 1703 1704 q = blk_trace_get_queue(bdev); 1705 if (q == NULL) 1706 goto out_bdput; 1707 1708 mutex_lock(&bdev->bd_mutex); 1709 1710 if (attr == &dev_attr_enable) { 1711 if (value) 1712 ret = blk_trace_setup_queue(q, bdev); 1713 else 1714 ret = blk_trace_remove_queue(q); 1715 goto out_unlock_bdev; 1716 } 1717 1718 ret = 0; 1719 if (q->blk_trace == NULL) 1720 ret = blk_trace_setup_queue(q, bdev); 1721 1722 if (ret == 0) { 1723 if (attr == &dev_attr_act_mask) 1724 q->blk_trace->act_mask = value; 1725 else if (attr == &dev_attr_pid) 1726 q->blk_trace->pid = value; 1727 else if (attr == &dev_attr_start_lba) 1728 q->blk_trace->start_lba = value; 1729 else if (attr == &dev_attr_end_lba) 1730 q->blk_trace->end_lba = value; 1731 } 1732 1733 out_unlock_bdev: 1734 mutex_unlock(&bdev->bd_mutex); 1735 out_bdput: 1736 bdput(bdev); 1737 out: 1738 return ret ? ret : count; 1739 } 1740 1741 int blk_trace_init_sysfs(struct device *dev) 1742 { 1743 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1744 } 1745 1746 void blk_trace_remove_sysfs(struct device *dev) 1747 { 1748 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1749 } 1750 1751 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1752 1753 #ifdef CONFIG_EVENT_TRACING 1754 1755 void blk_dump_cmd(char *buf, struct request *rq) 1756 { 1757 int i, end; 1758 int len = rq->cmd_len; 1759 unsigned char *cmd = rq->cmd; 1760 1761 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) { 1762 buf[0] = '\0'; 1763 return; 1764 } 1765 1766 for (end = len - 1; end >= 0; end--) 1767 if (cmd[end]) 1768 break; 1769 end++; 1770 1771 for (i = 0; i < len; i++) { 1772 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]); 1773 if (i == end && end != len - 1) { 1774 sprintf(buf, " .."); 1775 break; 1776 } 1777 } 1778 } 1779 1780 void blk_fill_rwbs(char *rwbs, int op, u32 rw, int bytes) 1781 { 1782 int i = 0; 1783 1784 if (rw & REQ_PREFLUSH) 1785 rwbs[i++] = 'F'; 1786 1787 switch (op) { 1788 case REQ_OP_WRITE: 1789 case REQ_OP_WRITE_SAME: 1790 rwbs[i++] = 'W'; 1791 break; 1792 case REQ_OP_DISCARD: 1793 rwbs[i++] = 'D'; 1794 break; 1795 case REQ_OP_SECURE_ERASE: 1796 rwbs[i++] = 'D'; 1797 rwbs[i++] = 'E'; 1798 break; 1799 case REQ_OP_FLUSH: 1800 rwbs[i++] = 'F'; 1801 break; 1802 case REQ_OP_READ: 1803 rwbs[i++] = 'R'; 1804 break; 1805 default: 1806 rwbs[i++] = 'N'; 1807 } 1808 1809 if (rw & REQ_FUA) 1810 rwbs[i++] = 'F'; 1811 if (rw & REQ_RAHEAD) 1812 rwbs[i++] = 'A'; 1813 if (rw & REQ_SYNC) 1814 rwbs[i++] = 'S'; 1815 if (rw & REQ_META) 1816 rwbs[i++] = 'M'; 1817 1818 rwbs[i] = '\0'; 1819 } 1820 EXPORT_SYMBOL_GPL(blk_fill_rwbs); 1821 1822 #endif /* CONFIG_EVENT_TRACING */ 1823 1824