1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> 4 * 5 */ 6 7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 8 9 #include <linux/kernel.h> 10 #include <linux/blkdev.h> 11 #include <linux/blktrace_api.h> 12 #include <linux/percpu.h> 13 #include <linux/init.h> 14 #include <linux/mutex.h> 15 #include <linux/slab.h> 16 #include <linux/debugfs.h> 17 #include <linux/export.h> 18 #include <linux/time.h> 19 #include <linux/uaccess.h> 20 #include <linux/list.h> 21 #include <linux/blk-cgroup.h> 22 23 #include "../../block/blk.h" 24 25 #include <trace/events/block.h> 26 27 #include "trace_output.h" 28 29 #ifdef CONFIG_BLK_DEV_IO_TRACE 30 31 static unsigned int blktrace_seq __read_mostly = 1; 32 33 static struct trace_array *blk_tr; 34 static bool blk_tracer_enabled __read_mostly; 35 36 static LIST_HEAD(running_trace_list); 37 static __cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(running_trace_lock); 38 39 /* Select an alternative, minimalistic output than the original one */ 40 #define TRACE_BLK_OPT_CLASSIC 0x1 41 #define TRACE_BLK_OPT_CGROUP 0x2 42 #define TRACE_BLK_OPT_CGNAME 0x4 43 44 static struct tracer_opt blk_tracer_opts[] = { 45 /* Default disable the minimalistic output */ 46 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 47 #ifdef CONFIG_BLK_CGROUP 48 { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) }, 49 { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) }, 50 #endif 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 DEFINE_MUTEX(blk_probe_mutex); 61 static int blk_probes_ref; 62 63 static void blk_register_tracepoints(void); 64 static void blk_unregister_tracepoints(void); 65 66 /* 67 * Send out a notify message. 68 */ 69 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 70 const void *data, size_t len, u64 cgid) 71 { 72 struct blk_io_trace *t; 73 struct ring_buffer_event *event = NULL; 74 struct trace_buffer *buffer = NULL; 75 unsigned int trace_ctx = 0; 76 int cpu = smp_processor_id(); 77 bool blk_tracer = blk_tracer_enabled; 78 ssize_t cgid_len = cgid ? sizeof(cgid) : 0; 79 80 if (blk_tracer) { 81 buffer = blk_tr->array_buffer.buffer; 82 trace_ctx = tracing_gen_ctx_flags(0); 83 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 84 sizeof(*t) + len + cgid_len, 85 trace_ctx); 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 + cgid_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 | (cgid ? __BLK_TN_CGROUP : 0); 102 t->pid = pid; 103 t->cpu = cpu; 104 t->pdu_len = len + cgid_len; 105 if (cgid_len) 106 memcpy((void *)t + sizeof(*t), &cgid, cgid_len); 107 memcpy((void *) t + sizeof(*t) + cgid_len, data, len); 108 109 if (blk_tracer) 110 trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx); 111 } 112 } 113 114 /* 115 * Send out a notify for this process, if we haven't done so since a trace 116 * started 117 */ 118 static void trace_note_tsk(struct task_struct *tsk) 119 { 120 unsigned long flags; 121 struct blk_trace *bt; 122 123 tsk->btrace_seq = blktrace_seq; 124 raw_spin_lock_irqsave(&running_trace_lock, flags); 125 list_for_each_entry(bt, &running_trace_list, running_list) { 126 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, 127 sizeof(tsk->comm), 0); 128 } 129 raw_spin_unlock_irqrestore(&running_trace_lock, flags); 130 } 131 132 static void trace_note_time(struct blk_trace *bt) 133 { 134 struct timespec64 now; 135 unsigned long flags; 136 u32 words[2]; 137 138 /* need to check user space to see if this breaks in y2038 or y2106 */ 139 ktime_get_real_ts64(&now); 140 words[0] = (u32)now.tv_sec; 141 words[1] = now.tv_nsec; 142 143 local_irq_save(flags); 144 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), 0); 145 local_irq_restore(flags); 146 } 147 148 void __blk_trace_note_message(struct blk_trace *bt, 149 struct cgroup_subsys_state *css, const char *fmt, ...) 150 { 151 int n; 152 va_list args; 153 unsigned long flags; 154 char *buf; 155 u64 cgid = 0; 156 157 if (unlikely(bt->trace_state != Blktrace_running && 158 !blk_tracer_enabled)) 159 return; 160 161 /* 162 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note 163 * message to the trace. 164 */ 165 if (!(bt->act_mask & BLK_TC_NOTIFY)) 166 return; 167 168 local_irq_save(flags); 169 buf = this_cpu_ptr(bt->msg_data); 170 va_start(args, fmt); 171 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 172 va_end(args); 173 174 #ifdef CONFIG_BLK_CGROUP 175 if (css && (blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP)) 176 cgid = cgroup_id(css->cgroup); 177 else 178 cgid = 1; 179 #endif 180 trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n, cgid); 181 local_irq_restore(flags); 182 } 183 EXPORT_SYMBOL_GPL(__blk_trace_note_message); 184 185 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 186 pid_t pid) 187 { 188 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 189 return 1; 190 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 191 return 1; 192 if (bt->pid && pid != bt->pid) 193 return 1; 194 195 return 0; 196 } 197 198 /* 199 * Data direction bit lookup 200 */ 201 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 202 BLK_TC_ACT(BLK_TC_WRITE) }; 203 204 #define BLK_TC_RAHEAD BLK_TC_AHEAD 205 #define BLK_TC_PREFLUSH BLK_TC_FLUSH 206 207 /* The ilog2() calls fall out because they're constant */ 208 #define MASK_TC_BIT(rw, __name) ((__force u32)(rw & REQ_ ## __name) << \ 209 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name)) 210 211 /* 212 * The worker for the various blk_add_trace*() types. Fills out a 213 * blk_io_trace structure and places it in a per-cpu subbuffer. 214 */ 215 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 216 const blk_opf_t opf, u32 what, int error, 217 int pdu_len, void *pdu_data, u64 cgid) 218 { 219 struct task_struct *tsk = current; 220 struct ring_buffer_event *event = NULL; 221 struct trace_buffer *buffer = NULL; 222 struct blk_io_trace *t; 223 unsigned long flags = 0; 224 unsigned long *sequence; 225 unsigned int trace_ctx = 0; 226 pid_t pid; 227 int cpu; 228 bool blk_tracer = blk_tracer_enabled; 229 ssize_t cgid_len = cgid ? sizeof(cgid) : 0; 230 const enum req_op op = opf & REQ_OP_MASK; 231 232 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 233 return; 234 235 what |= ddir_act[op_is_write(op) ? WRITE : READ]; 236 what |= MASK_TC_BIT(opf, SYNC); 237 what |= MASK_TC_BIT(opf, RAHEAD); 238 what |= MASK_TC_BIT(opf, META); 239 what |= MASK_TC_BIT(opf, PREFLUSH); 240 what |= MASK_TC_BIT(opf, FUA); 241 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE) 242 what |= BLK_TC_ACT(BLK_TC_DISCARD); 243 if (op == REQ_OP_FLUSH) 244 what |= BLK_TC_ACT(BLK_TC_FLUSH); 245 if (cgid) 246 what |= __BLK_TA_CGROUP; 247 248 pid = tsk->pid; 249 if (act_log_check(bt, what, sector, pid)) 250 return; 251 cpu = raw_smp_processor_id(); 252 253 if (blk_tracer) { 254 tracing_record_cmdline(current); 255 256 buffer = blk_tr->array_buffer.buffer; 257 trace_ctx = tracing_gen_ctx_flags(0); 258 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 259 sizeof(*t) + pdu_len + cgid_len, 260 trace_ctx); 261 if (!event) 262 return; 263 t = ring_buffer_event_data(event); 264 goto record_it; 265 } 266 267 if (unlikely(tsk->btrace_seq != blktrace_seq)) 268 trace_note_tsk(tsk); 269 270 /* 271 * A word about the locking here - we disable interrupts to reserve 272 * some space in the relay per-cpu buffer, to prevent an irq 273 * from coming in and stepping on our toes. 274 */ 275 local_irq_save(flags); 276 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len); 277 if (t) { 278 sequence = per_cpu_ptr(bt->sequence, cpu); 279 280 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 281 t->sequence = ++(*sequence); 282 t->time = ktime_to_ns(ktime_get()); 283 record_it: 284 /* 285 * These two are not needed in ftrace as they are in the 286 * generic trace_entry, filled by tracing_generic_entry_update, 287 * but for the trace_event->bin() synthesizer benefit we do it 288 * here too. 289 */ 290 t->cpu = cpu; 291 t->pid = pid; 292 293 t->sector = sector; 294 t->bytes = bytes; 295 t->action = what; 296 t->device = bt->dev; 297 t->error = error; 298 t->pdu_len = pdu_len + cgid_len; 299 300 if (cgid_len) 301 memcpy((void *)t + sizeof(*t), &cgid, cgid_len); 302 if (pdu_len) 303 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len); 304 305 if (blk_tracer) { 306 trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx); 307 return; 308 } 309 } 310 311 local_irq_restore(flags); 312 } 313 314 static void blk_trace_free(struct request_queue *q, struct blk_trace *bt) 315 { 316 relay_close(bt->rchan); 317 318 /* 319 * If 'bt->dir' is not set, then both 'dropped' and 'msg' are created 320 * under 'q->debugfs_dir', thus lookup and remove them. 321 */ 322 if (!bt->dir) { 323 debugfs_remove(debugfs_lookup("dropped", q->debugfs_dir)); 324 debugfs_remove(debugfs_lookup("msg", q->debugfs_dir)); 325 } else { 326 debugfs_remove(bt->dir); 327 } 328 free_percpu(bt->sequence); 329 free_percpu(bt->msg_data); 330 kfree(bt); 331 } 332 333 static void get_probe_ref(void) 334 { 335 mutex_lock(&blk_probe_mutex); 336 if (++blk_probes_ref == 1) 337 blk_register_tracepoints(); 338 mutex_unlock(&blk_probe_mutex); 339 } 340 341 static void put_probe_ref(void) 342 { 343 mutex_lock(&blk_probe_mutex); 344 if (!--blk_probes_ref) 345 blk_unregister_tracepoints(); 346 mutex_unlock(&blk_probe_mutex); 347 } 348 349 static int blk_trace_start(struct blk_trace *bt) 350 { 351 if (bt->trace_state != Blktrace_setup && 352 bt->trace_state != Blktrace_stopped) 353 return -EINVAL; 354 355 blktrace_seq++; 356 smp_mb(); 357 bt->trace_state = Blktrace_running; 358 raw_spin_lock_irq(&running_trace_lock); 359 list_add(&bt->running_list, &running_trace_list); 360 raw_spin_unlock_irq(&running_trace_lock); 361 trace_note_time(bt); 362 363 return 0; 364 } 365 366 static int blk_trace_stop(struct blk_trace *bt) 367 { 368 if (bt->trace_state != Blktrace_running) 369 return -EINVAL; 370 371 bt->trace_state = Blktrace_stopped; 372 raw_spin_lock_irq(&running_trace_lock); 373 list_del_init(&bt->running_list); 374 raw_spin_unlock_irq(&running_trace_lock); 375 relay_flush(bt->rchan); 376 377 return 0; 378 } 379 380 static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt) 381 { 382 blk_trace_stop(bt); 383 synchronize_rcu(); 384 blk_trace_free(q, bt); 385 put_probe_ref(); 386 } 387 388 static int __blk_trace_remove(struct request_queue *q) 389 { 390 struct blk_trace *bt; 391 392 bt = rcu_replace_pointer(q->blk_trace, NULL, 393 lockdep_is_held(&q->debugfs_mutex)); 394 if (!bt) 395 return -EINVAL; 396 397 blk_trace_cleanup(q, bt); 398 399 return 0; 400 } 401 402 int blk_trace_remove(struct request_queue *q) 403 { 404 int ret; 405 406 mutex_lock(&q->debugfs_mutex); 407 ret = __blk_trace_remove(q); 408 mutex_unlock(&q->debugfs_mutex); 409 410 return ret; 411 } 412 EXPORT_SYMBOL_GPL(blk_trace_remove); 413 414 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 415 size_t count, loff_t *ppos) 416 { 417 struct blk_trace *bt = filp->private_data; 418 char buf[16]; 419 420 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 421 422 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 423 } 424 425 static const struct file_operations blk_dropped_fops = { 426 .owner = THIS_MODULE, 427 .open = simple_open, 428 .read = blk_dropped_read, 429 .llseek = default_llseek, 430 }; 431 432 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 433 size_t count, loff_t *ppos) 434 { 435 char *msg; 436 struct blk_trace *bt; 437 438 if (count >= BLK_TN_MAX_MSG) 439 return -EINVAL; 440 441 msg = memdup_user_nul(buffer, count); 442 if (IS_ERR(msg)) 443 return PTR_ERR(msg); 444 445 bt = filp->private_data; 446 __blk_trace_note_message(bt, NULL, "%s", msg); 447 kfree(msg); 448 449 return count; 450 } 451 452 static const struct file_operations blk_msg_fops = { 453 .owner = THIS_MODULE, 454 .open = simple_open, 455 .write = blk_msg_write, 456 .llseek = noop_llseek, 457 }; 458 459 /* 460 * Keep track of how many times we encountered a full subbuffer, to aid 461 * the user space app in telling how many lost events there were. 462 */ 463 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 464 void *prev_subbuf, size_t prev_padding) 465 { 466 struct blk_trace *bt; 467 468 if (!relay_buf_full(buf)) 469 return 1; 470 471 bt = buf->chan->private_data; 472 atomic_inc(&bt->dropped); 473 return 0; 474 } 475 476 static int blk_remove_buf_file_callback(struct dentry *dentry) 477 { 478 debugfs_remove(dentry); 479 480 return 0; 481 } 482 483 static struct dentry *blk_create_buf_file_callback(const char *filename, 484 struct dentry *parent, 485 umode_t mode, 486 struct rchan_buf *buf, 487 int *is_global) 488 { 489 return debugfs_create_file(filename, mode, parent, buf, 490 &relay_file_operations); 491 } 492 493 static const struct rchan_callbacks blk_relay_callbacks = { 494 .subbuf_start = blk_subbuf_start_callback, 495 .create_buf_file = blk_create_buf_file_callback, 496 .remove_buf_file = blk_remove_buf_file_callback, 497 }; 498 499 static void blk_trace_setup_lba(struct blk_trace *bt, 500 struct block_device *bdev) 501 { 502 if (bdev) { 503 bt->start_lba = bdev->bd_start_sect; 504 bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev); 505 } else { 506 bt->start_lba = 0; 507 bt->end_lba = -1ULL; 508 } 509 } 510 511 /* 512 * Setup everything required to start tracing 513 */ 514 static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 515 struct block_device *bdev, 516 struct blk_user_trace_setup *buts) 517 { 518 struct blk_trace *bt = NULL; 519 struct dentry *dir = NULL; 520 int ret; 521 522 lockdep_assert_held(&q->debugfs_mutex); 523 524 if (!buts->buf_size || !buts->buf_nr) 525 return -EINVAL; 526 527 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 528 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 529 530 /* 531 * some device names have larger paths - convert the slashes 532 * to underscores for this to work as expected 533 */ 534 strreplace(buts->name, '/', '_'); 535 536 /* 537 * bdev can be NULL, as with scsi-generic, this is a helpful as 538 * we can be. 539 */ 540 if (rcu_dereference_protected(q->blk_trace, 541 lockdep_is_held(&q->debugfs_mutex))) { 542 pr_warn("Concurrent blktraces are not allowed on %s\n", 543 buts->name); 544 return -EBUSY; 545 } 546 547 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 548 if (!bt) 549 return -ENOMEM; 550 551 ret = -ENOMEM; 552 bt->sequence = alloc_percpu(unsigned long); 553 if (!bt->sequence) 554 goto err; 555 556 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 557 if (!bt->msg_data) 558 goto err; 559 560 /* 561 * When tracing the whole disk reuse the existing debugfs directory 562 * created by the block layer on init. For partitions block devices, 563 * and scsi-generic block devices we create a temporary new debugfs 564 * directory that will be removed once the trace ends. 565 */ 566 if (bdev && !bdev_is_partition(bdev)) 567 dir = q->debugfs_dir; 568 else 569 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root); 570 571 /* 572 * As blktrace relies on debugfs for its interface the debugfs directory 573 * is required, contrary to the usual mantra of not checking for debugfs 574 * files or directories. 575 */ 576 if (IS_ERR_OR_NULL(dir)) { 577 pr_warn("debugfs_dir not present for %s so skipping\n", 578 buts->name); 579 ret = -ENOENT; 580 goto err; 581 } 582 583 bt->dev = dev; 584 atomic_set(&bt->dropped, 0); 585 INIT_LIST_HEAD(&bt->running_list); 586 587 ret = -EIO; 588 debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops); 589 debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 590 591 bt->rchan = relay_open("trace", dir, buts->buf_size, 592 buts->buf_nr, &blk_relay_callbacks, bt); 593 if (!bt->rchan) 594 goto err; 595 596 bt->act_mask = buts->act_mask; 597 if (!bt->act_mask) 598 bt->act_mask = (u16) -1; 599 600 blk_trace_setup_lba(bt, bdev); 601 602 /* overwrite with user settings */ 603 if (buts->start_lba) 604 bt->start_lba = buts->start_lba; 605 if (buts->end_lba) 606 bt->end_lba = buts->end_lba; 607 608 bt->pid = buts->pid; 609 bt->trace_state = Blktrace_setup; 610 611 rcu_assign_pointer(q->blk_trace, bt); 612 get_probe_ref(); 613 614 ret = 0; 615 err: 616 if (ret) 617 blk_trace_free(q, bt); 618 return ret; 619 } 620 621 static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 622 struct block_device *bdev, char __user *arg) 623 { 624 struct blk_user_trace_setup buts; 625 int ret; 626 627 ret = copy_from_user(&buts, arg, sizeof(buts)); 628 if (ret) 629 return -EFAULT; 630 631 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 632 if (ret) 633 return ret; 634 635 if (copy_to_user(arg, &buts, sizeof(buts))) { 636 __blk_trace_remove(q); 637 return -EFAULT; 638 } 639 return 0; 640 } 641 642 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 643 struct block_device *bdev, 644 char __user *arg) 645 { 646 int ret; 647 648 mutex_lock(&q->debugfs_mutex); 649 ret = __blk_trace_setup(q, name, dev, bdev, arg); 650 mutex_unlock(&q->debugfs_mutex); 651 652 return ret; 653 } 654 EXPORT_SYMBOL_GPL(blk_trace_setup); 655 656 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 657 static int compat_blk_trace_setup(struct request_queue *q, char *name, 658 dev_t dev, struct block_device *bdev, 659 char __user *arg) 660 { 661 struct blk_user_trace_setup buts; 662 struct compat_blk_user_trace_setup cbuts; 663 int ret; 664 665 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 666 return -EFAULT; 667 668 buts = (struct blk_user_trace_setup) { 669 .act_mask = cbuts.act_mask, 670 .buf_size = cbuts.buf_size, 671 .buf_nr = cbuts.buf_nr, 672 .start_lba = cbuts.start_lba, 673 .end_lba = cbuts.end_lba, 674 .pid = cbuts.pid, 675 }; 676 677 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 678 if (ret) 679 return ret; 680 681 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) { 682 __blk_trace_remove(q); 683 return -EFAULT; 684 } 685 686 return 0; 687 } 688 #endif 689 690 static int __blk_trace_startstop(struct request_queue *q, int start) 691 { 692 struct blk_trace *bt; 693 694 bt = rcu_dereference_protected(q->blk_trace, 695 lockdep_is_held(&q->debugfs_mutex)); 696 if (bt == NULL) 697 return -EINVAL; 698 699 if (start) 700 return blk_trace_start(bt); 701 else 702 return blk_trace_stop(bt); 703 } 704 705 int blk_trace_startstop(struct request_queue *q, int start) 706 { 707 int ret; 708 709 mutex_lock(&q->debugfs_mutex); 710 ret = __blk_trace_startstop(q, start); 711 mutex_unlock(&q->debugfs_mutex); 712 713 return ret; 714 } 715 EXPORT_SYMBOL_GPL(blk_trace_startstop); 716 717 /* 718 * When reading or writing the blktrace sysfs files, the references to the 719 * opened sysfs or device files should prevent the underlying block device 720 * from being removed. So no further delete protection is really needed. 721 */ 722 723 /** 724 * blk_trace_ioctl - handle the ioctls associated with tracing 725 * @bdev: the block device 726 * @cmd: the ioctl cmd 727 * @arg: the argument data, if any 728 * 729 **/ 730 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 731 { 732 struct request_queue *q; 733 int ret, start = 0; 734 char b[BDEVNAME_SIZE]; 735 736 q = bdev_get_queue(bdev); 737 if (!q) 738 return -ENXIO; 739 740 mutex_lock(&q->debugfs_mutex); 741 742 switch (cmd) { 743 case BLKTRACESETUP: 744 snprintf(b, sizeof(b), "%pg", bdev); 745 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 746 break; 747 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 748 case BLKTRACESETUP32: 749 snprintf(b, sizeof(b), "%pg", bdev); 750 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 751 break; 752 #endif 753 case BLKTRACESTART: 754 start = 1; 755 fallthrough; 756 case BLKTRACESTOP: 757 ret = __blk_trace_startstop(q, start); 758 break; 759 case BLKTRACETEARDOWN: 760 ret = __blk_trace_remove(q); 761 break; 762 default: 763 ret = -ENOTTY; 764 break; 765 } 766 767 mutex_unlock(&q->debugfs_mutex); 768 return ret; 769 } 770 771 /** 772 * blk_trace_shutdown - stop and cleanup trace structures 773 * @q: the request queue associated with the device 774 * 775 **/ 776 void blk_trace_shutdown(struct request_queue *q) 777 { 778 if (rcu_dereference_protected(q->blk_trace, 779 lockdep_is_held(&q->debugfs_mutex))) 780 __blk_trace_remove(q); 781 } 782 783 #ifdef CONFIG_BLK_CGROUP 784 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) 785 { 786 struct cgroup_subsys_state *blkcg_css; 787 struct blk_trace *bt; 788 789 /* We don't use the 'bt' value here except as an optimization... */ 790 bt = rcu_dereference_protected(q->blk_trace, 1); 791 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP)) 792 return 0; 793 794 blkcg_css = bio_blkcg_css(bio); 795 if (!blkcg_css) 796 return 0; 797 return cgroup_id(blkcg_css->cgroup); 798 } 799 #else 800 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) 801 { 802 return 0; 803 } 804 #endif 805 806 static u64 807 blk_trace_request_get_cgid(struct request *rq) 808 { 809 if (!rq->bio) 810 return 0; 811 /* Use the first bio */ 812 return blk_trace_bio_get_cgid(rq->q, rq->bio); 813 } 814 815 /* 816 * blktrace probes 817 */ 818 819 /** 820 * blk_add_trace_rq - Add a trace for a request oriented action 821 * @rq: the source request 822 * @error: return status to log 823 * @nr_bytes: number of completed bytes 824 * @what: the action 825 * @cgid: the cgroup info 826 * 827 * Description: 828 * Records an action against a request. Will log the bio offset + size. 829 * 830 **/ 831 static void blk_add_trace_rq(struct request *rq, blk_status_t error, 832 unsigned int nr_bytes, u32 what, u64 cgid) 833 { 834 struct blk_trace *bt; 835 836 rcu_read_lock(); 837 bt = rcu_dereference(rq->q->blk_trace); 838 if (likely(!bt)) { 839 rcu_read_unlock(); 840 return; 841 } 842 843 if (blk_rq_is_passthrough(rq)) 844 what |= BLK_TC_ACT(BLK_TC_PC); 845 else 846 what |= BLK_TC_ACT(BLK_TC_FS); 847 848 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, rq->cmd_flags, 849 what, blk_status_to_errno(error), 0, NULL, cgid); 850 rcu_read_unlock(); 851 } 852 853 static void blk_add_trace_rq_insert(void *ignore, struct request *rq) 854 { 855 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT, 856 blk_trace_request_get_cgid(rq)); 857 } 858 859 static void blk_add_trace_rq_issue(void *ignore, struct request *rq) 860 { 861 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE, 862 blk_trace_request_get_cgid(rq)); 863 } 864 865 static void blk_add_trace_rq_merge(void *ignore, struct request *rq) 866 { 867 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE, 868 blk_trace_request_get_cgid(rq)); 869 } 870 871 static void blk_add_trace_rq_requeue(void *ignore, struct request *rq) 872 { 873 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE, 874 blk_trace_request_get_cgid(rq)); 875 } 876 877 static void blk_add_trace_rq_complete(void *ignore, struct request *rq, 878 blk_status_t error, unsigned int nr_bytes) 879 { 880 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE, 881 blk_trace_request_get_cgid(rq)); 882 } 883 884 /** 885 * blk_add_trace_bio - Add a trace for a bio oriented action 886 * @q: queue the io is for 887 * @bio: the source bio 888 * @what: the action 889 * @error: error, if any 890 * 891 * Description: 892 * Records an action against a bio. Will log the bio offset + size. 893 * 894 **/ 895 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 896 u32 what, int error) 897 { 898 struct blk_trace *bt; 899 900 rcu_read_lock(); 901 bt = rcu_dereference(q->blk_trace); 902 if (likely(!bt)) { 903 rcu_read_unlock(); 904 return; 905 } 906 907 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 908 bio->bi_opf, what, error, 0, NULL, 909 blk_trace_bio_get_cgid(q, bio)); 910 rcu_read_unlock(); 911 } 912 913 static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio) 914 { 915 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0); 916 } 917 918 static void blk_add_trace_bio_complete(void *ignore, 919 struct request_queue *q, struct bio *bio) 920 { 921 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, 922 blk_status_to_errno(bio->bi_status)); 923 } 924 925 static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio) 926 { 927 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE, 928 0); 929 } 930 931 static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio) 932 { 933 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE, 934 0); 935 } 936 937 static void blk_add_trace_bio_queue(void *ignore, struct bio *bio) 938 { 939 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0); 940 } 941 942 static void blk_add_trace_getrq(void *ignore, struct bio *bio) 943 { 944 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0); 945 } 946 947 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 948 { 949 struct blk_trace *bt; 950 951 rcu_read_lock(); 952 bt = rcu_dereference(q->blk_trace); 953 if (bt) 954 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0); 955 rcu_read_unlock(); 956 } 957 958 static void blk_add_trace_unplug(void *ignore, struct request_queue *q, 959 unsigned int depth, bool explicit) 960 { 961 struct blk_trace *bt; 962 963 rcu_read_lock(); 964 bt = rcu_dereference(q->blk_trace); 965 if (bt) { 966 __be64 rpdu = cpu_to_be64(depth); 967 u32 what; 968 969 if (explicit) 970 what = BLK_TA_UNPLUG_IO; 971 else 972 what = BLK_TA_UNPLUG_TIMER; 973 974 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0); 975 } 976 rcu_read_unlock(); 977 } 978 979 static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu) 980 { 981 struct request_queue *q = bio->bi_bdev->bd_disk->queue; 982 struct blk_trace *bt; 983 984 rcu_read_lock(); 985 bt = rcu_dereference(q->blk_trace); 986 if (bt) { 987 __be64 rpdu = cpu_to_be64(pdu); 988 989 __blk_add_trace(bt, bio->bi_iter.bi_sector, 990 bio->bi_iter.bi_size, bio->bi_opf, BLK_TA_SPLIT, 991 blk_status_to_errno(bio->bi_status), 992 sizeof(rpdu), &rpdu, 993 blk_trace_bio_get_cgid(q, bio)); 994 } 995 rcu_read_unlock(); 996 } 997 998 /** 999 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation 1000 * @ignore: trace callback data parameter (not used) 1001 * @bio: the source bio 1002 * @dev: source device 1003 * @from: source sector 1004 * 1005 * Called after a bio is remapped to a different device and/or sector. 1006 **/ 1007 static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev, 1008 sector_t from) 1009 { 1010 struct request_queue *q = bio->bi_bdev->bd_disk->queue; 1011 struct blk_trace *bt; 1012 struct blk_io_trace_remap r; 1013 1014 rcu_read_lock(); 1015 bt = rcu_dereference(q->blk_trace); 1016 if (likely(!bt)) { 1017 rcu_read_unlock(); 1018 return; 1019 } 1020 1021 r.device_from = cpu_to_be32(dev); 1022 r.device_to = cpu_to_be32(bio_dev(bio)); 1023 r.sector_from = cpu_to_be64(from); 1024 1025 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 1026 bio->bi_opf, BLK_TA_REMAP, 1027 blk_status_to_errno(bio->bi_status), 1028 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio)); 1029 rcu_read_unlock(); 1030 } 1031 1032 /** 1033 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 1034 * @ignore: trace callback data parameter (not used) 1035 * @rq: the source request 1036 * @dev: target device 1037 * @from: source sector 1038 * 1039 * Description: 1040 * Device mapper remaps request to other devices. 1041 * Add a trace for that action. 1042 * 1043 **/ 1044 static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev, 1045 sector_t from) 1046 { 1047 struct blk_trace *bt; 1048 struct blk_io_trace_remap r; 1049 1050 rcu_read_lock(); 1051 bt = rcu_dereference(rq->q->blk_trace); 1052 if (likely(!bt)) { 1053 rcu_read_unlock(); 1054 return; 1055 } 1056 1057 r.device_from = cpu_to_be32(dev); 1058 r.device_to = cpu_to_be32(disk_devt(rq->q->disk)); 1059 r.sector_from = cpu_to_be64(from); 1060 1061 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 1062 rq->cmd_flags, BLK_TA_REMAP, 0, 1063 sizeof(r), &r, blk_trace_request_get_cgid(rq)); 1064 rcu_read_unlock(); 1065 } 1066 1067 /** 1068 * blk_add_driver_data - Add binary message with driver-specific data 1069 * @rq: io request 1070 * @data: driver-specific data 1071 * @len: length of driver-specific data 1072 * 1073 * Description: 1074 * Some drivers might want to write driver-specific data per request. 1075 * 1076 **/ 1077 void blk_add_driver_data(struct request *rq, void *data, size_t len) 1078 { 1079 struct blk_trace *bt; 1080 1081 rcu_read_lock(); 1082 bt = rcu_dereference(rq->q->blk_trace); 1083 if (likely(!bt)) { 1084 rcu_read_unlock(); 1085 return; 1086 } 1087 1088 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 1089 BLK_TA_DRV_DATA, 0, len, data, 1090 blk_trace_request_get_cgid(rq)); 1091 rcu_read_unlock(); 1092 } 1093 EXPORT_SYMBOL_GPL(blk_add_driver_data); 1094 1095 static void blk_register_tracepoints(void) 1096 { 1097 int ret; 1098 1099 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1100 WARN_ON(ret); 1101 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1102 WARN_ON(ret); 1103 ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL); 1104 WARN_ON(ret); 1105 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1106 WARN_ON(ret); 1107 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1108 WARN_ON(ret); 1109 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1110 WARN_ON(ret); 1111 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1112 WARN_ON(ret); 1113 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1114 WARN_ON(ret); 1115 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1116 WARN_ON(ret); 1117 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1118 WARN_ON(ret); 1119 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 1120 WARN_ON(ret); 1121 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 1122 WARN_ON(ret); 1123 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL); 1124 WARN_ON(ret); 1125 ret = register_trace_block_split(blk_add_trace_split, NULL); 1126 WARN_ON(ret); 1127 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1128 WARN_ON(ret); 1129 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1130 WARN_ON(ret); 1131 } 1132 1133 static void blk_unregister_tracepoints(void) 1134 { 1135 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1136 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1137 unregister_trace_block_split(blk_add_trace_split, NULL); 1138 unregister_trace_block_unplug(blk_add_trace_unplug, NULL); 1139 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1140 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1141 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1142 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1143 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1144 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1145 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1146 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1147 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1148 unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL); 1149 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1150 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1151 1152 tracepoint_synchronize_unregister(); 1153 } 1154 1155 /* 1156 * struct blk_io_tracer formatting routines 1157 */ 1158 1159 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1160 { 1161 int i = 0; 1162 int tc = t->action >> BLK_TC_SHIFT; 1163 1164 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { 1165 rwbs[i++] = 'N'; 1166 goto out; 1167 } 1168 1169 if (tc & BLK_TC_FLUSH) 1170 rwbs[i++] = 'F'; 1171 1172 if (tc & BLK_TC_DISCARD) 1173 rwbs[i++] = 'D'; 1174 else if (tc & BLK_TC_WRITE) 1175 rwbs[i++] = 'W'; 1176 else if (t->bytes) 1177 rwbs[i++] = 'R'; 1178 else 1179 rwbs[i++] = 'N'; 1180 1181 if (tc & BLK_TC_FUA) 1182 rwbs[i++] = 'F'; 1183 if (tc & BLK_TC_AHEAD) 1184 rwbs[i++] = 'A'; 1185 if (tc & BLK_TC_SYNC) 1186 rwbs[i++] = 'S'; 1187 if (tc & BLK_TC_META) 1188 rwbs[i++] = 'M'; 1189 out: 1190 rwbs[i] = '\0'; 1191 } 1192 1193 static inline 1194 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1195 { 1196 return (const struct blk_io_trace *)ent; 1197 } 1198 1199 static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg) 1200 { 1201 return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0); 1202 } 1203 1204 static inline u64 t_cgid(const struct trace_entry *ent) 1205 { 1206 return *(u64 *)(te_blk_io_trace(ent) + 1); 1207 } 1208 1209 static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg) 1210 { 1211 return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0); 1212 } 1213 1214 static inline u32 t_action(const struct trace_entry *ent) 1215 { 1216 return te_blk_io_trace(ent)->action; 1217 } 1218 1219 static inline u32 t_bytes(const struct trace_entry *ent) 1220 { 1221 return te_blk_io_trace(ent)->bytes; 1222 } 1223 1224 static inline u32 t_sec(const struct trace_entry *ent) 1225 { 1226 return te_blk_io_trace(ent)->bytes >> 9; 1227 } 1228 1229 static inline unsigned long long t_sector(const struct trace_entry *ent) 1230 { 1231 return te_blk_io_trace(ent)->sector; 1232 } 1233 1234 static inline __u16 t_error(const struct trace_entry *ent) 1235 { 1236 return te_blk_io_trace(ent)->error; 1237 } 1238 1239 static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg) 1240 { 1241 const __be64 *val = pdu_start(ent, has_cg); 1242 return be64_to_cpu(*val); 1243 } 1244 1245 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act, 1246 bool has_cg); 1247 1248 static void blk_log_action_classic(struct trace_iterator *iter, const char *act, 1249 bool has_cg) 1250 { 1251 char rwbs[RWBS_LEN]; 1252 unsigned long long ts = iter->ts; 1253 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1254 unsigned secs = (unsigned long)ts; 1255 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1256 1257 fill_rwbs(rwbs, t); 1258 1259 trace_seq_printf(&iter->seq, 1260 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1261 MAJOR(t->device), MINOR(t->device), iter->cpu, 1262 secs, nsec_rem, iter->ent->pid, act, rwbs); 1263 } 1264 1265 static void blk_log_action(struct trace_iterator *iter, const char *act, 1266 bool has_cg) 1267 { 1268 char rwbs[RWBS_LEN]; 1269 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1270 1271 fill_rwbs(rwbs, t); 1272 if (has_cg) { 1273 u64 id = t_cgid(iter->ent); 1274 1275 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) { 1276 char blkcg_name_buf[NAME_MAX + 1] = "<...>"; 1277 1278 cgroup_path_from_kernfs_id(id, blkcg_name_buf, 1279 sizeof(blkcg_name_buf)); 1280 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ", 1281 MAJOR(t->device), MINOR(t->device), 1282 blkcg_name_buf, act, rwbs); 1283 } else { 1284 /* 1285 * The cgid portion used to be "INO,GEN". Userland 1286 * builds a FILEID_INO32_GEN fid out of them and 1287 * opens the cgroup using open_by_handle_at(2). 1288 * While 32bit ino setups are still the same, 64bit 1289 * ones now use the 64bit ino as the whole ID and 1290 * no longer use generation. 1291 * 1292 * Regardless of the content, always output 1293 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can 1294 * be mapped back to @id on both 64 and 32bit ino 1295 * setups. See __kernfs_fh_to_dentry(). 1296 */ 1297 trace_seq_printf(&iter->seq, 1298 "%3d,%-3d %llx,%-llx %2s %3s ", 1299 MAJOR(t->device), MINOR(t->device), 1300 id & U32_MAX, id >> 32, act, rwbs); 1301 } 1302 } else 1303 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1304 MAJOR(t->device), MINOR(t->device), act, rwbs); 1305 } 1306 1307 static void blk_log_dump_pdu(struct trace_seq *s, 1308 const struct trace_entry *ent, bool has_cg) 1309 { 1310 const unsigned char *pdu_buf; 1311 int pdu_len; 1312 int i, end; 1313 1314 pdu_buf = pdu_start(ent, has_cg); 1315 pdu_len = pdu_real_len(ent, has_cg); 1316 1317 if (!pdu_len) 1318 return; 1319 1320 /* find the last zero that needs to be printed */ 1321 for (end = pdu_len - 1; end >= 0; end--) 1322 if (pdu_buf[end]) 1323 break; 1324 end++; 1325 1326 trace_seq_putc(s, '('); 1327 1328 for (i = 0; i < pdu_len; i++) { 1329 1330 trace_seq_printf(s, "%s%02x", 1331 i == 0 ? "" : " ", pdu_buf[i]); 1332 1333 /* 1334 * stop when the rest is just zeros and indicate so 1335 * with a ".." appended 1336 */ 1337 if (i == end && end != pdu_len - 1) { 1338 trace_seq_puts(s, " ..) "); 1339 return; 1340 } 1341 } 1342 1343 trace_seq_puts(s, ") "); 1344 } 1345 1346 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1347 { 1348 char cmd[TASK_COMM_LEN]; 1349 1350 trace_find_cmdline(ent->pid, cmd); 1351 1352 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1353 trace_seq_printf(s, "%u ", t_bytes(ent)); 1354 blk_log_dump_pdu(s, ent, has_cg); 1355 trace_seq_printf(s, "[%s]\n", cmd); 1356 } else { 1357 if (t_sec(ent)) 1358 trace_seq_printf(s, "%llu + %u [%s]\n", 1359 t_sector(ent), t_sec(ent), cmd); 1360 else 1361 trace_seq_printf(s, "[%s]\n", cmd); 1362 } 1363 } 1364 1365 static void blk_log_with_error(struct trace_seq *s, 1366 const struct trace_entry *ent, bool has_cg) 1367 { 1368 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1369 blk_log_dump_pdu(s, ent, has_cg); 1370 trace_seq_printf(s, "[%d]\n", t_error(ent)); 1371 } else { 1372 if (t_sec(ent)) 1373 trace_seq_printf(s, "%llu + %u [%d]\n", 1374 t_sector(ent), 1375 t_sec(ent), t_error(ent)); 1376 else 1377 trace_seq_printf(s, "%llu [%d]\n", 1378 t_sector(ent), t_error(ent)); 1379 } 1380 } 1381 1382 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1383 { 1384 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg); 1385 1386 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1387 t_sector(ent), t_sec(ent), 1388 MAJOR(be32_to_cpu(__r->device_from)), 1389 MINOR(be32_to_cpu(__r->device_from)), 1390 be64_to_cpu(__r->sector_from)); 1391 } 1392 1393 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1394 { 1395 char cmd[TASK_COMM_LEN]; 1396 1397 trace_find_cmdline(ent->pid, cmd); 1398 1399 trace_seq_printf(s, "[%s]\n", cmd); 1400 } 1401 1402 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1403 { 1404 char cmd[TASK_COMM_LEN]; 1405 1406 trace_find_cmdline(ent->pid, cmd); 1407 1408 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg)); 1409 } 1410 1411 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1412 { 1413 char cmd[TASK_COMM_LEN]; 1414 1415 trace_find_cmdline(ent->pid, cmd); 1416 1417 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1418 get_pdu_int(ent, has_cg), cmd); 1419 } 1420 1421 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent, 1422 bool has_cg) 1423 { 1424 1425 trace_seq_putmem(s, pdu_start(ent, has_cg), 1426 pdu_real_len(ent, has_cg)); 1427 trace_seq_putc(s, '\n'); 1428 } 1429 1430 /* 1431 * struct tracer operations 1432 */ 1433 1434 static void blk_tracer_print_header(struct seq_file *m) 1435 { 1436 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1437 return; 1438 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1439 "# | | | | | |\n"); 1440 } 1441 1442 static void blk_tracer_start(struct trace_array *tr) 1443 { 1444 blk_tracer_enabled = true; 1445 } 1446 1447 static int blk_tracer_init(struct trace_array *tr) 1448 { 1449 blk_tr = tr; 1450 blk_tracer_start(tr); 1451 return 0; 1452 } 1453 1454 static void blk_tracer_stop(struct trace_array *tr) 1455 { 1456 blk_tracer_enabled = false; 1457 } 1458 1459 static void blk_tracer_reset(struct trace_array *tr) 1460 { 1461 blk_tracer_stop(tr); 1462 } 1463 1464 static const struct { 1465 const char *act[2]; 1466 void (*print)(struct trace_seq *s, const struct trace_entry *ent, 1467 bool has_cg); 1468 } what2act[] = { 1469 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1470 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1471 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1472 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1473 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1474 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1475 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1476 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1477 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1478 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1479 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1480 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1481 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1482 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1483 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1484 }; 1485 1486 static enum print_line_t print_one_line(struct trace_iterator *iter, 1487 bool classic) 1488 { 1489 struct trace_array *tr = iter->tr; 1490 struct trace_seq *s = &iter->seq; 1491 const struct blk_io_trace *t; 1492 u16 what; 1493 bool long_act; 1494 blk_log_action_t *log_action; 1495 bool has_cg; 1496 1497 t = te_blk_io_trace(iter->ent); 1498 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP; 1499 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE); 1500 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1501 has_cg = t->action & __BLK_TA_CGROUP; 1502 1503 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { 1504 log_action(iter, long_act ? "message" : "m", has_cg); 1505 blk_log_msg(s, iter->ent, has_cg); 1506 return trace_handle_return(s); 1507 } 1508 1509 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1510 trace_seq_printf(s, "Unknown action %x\n", what); 1511 else { 1512 log_action(iter, what2act[what].act[long_act], has_cg); 1513 what2act[what].print(s, iter->ent, has_cg); 1514 } 1515 1516 return trace_handle_return(s); 1517 } 1518 1519 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1520 int flags, struct trace_event *event) 1521 { 1522 return print_one_line(iter, false); 1523 } 1524 1525 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1526 { 1527 struct trace_seq *s = &iter->seq; 1528 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1529 const int offset = offsetof(struct blk_io_trace, sector); 1530 struct blk_io_trace old = { 1531 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1532 .time = iter->ts, 1533 }; 1534 1535 trace_seq_putmem(s, &old, offset); 1536 trace_seq_putmem(s, &t->sector, 1537 sizeof(old) - offset + t->pdu_len); 1538 } 1539 1540 static enum print_line_t 1541 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1542 struct trace_event *event) 1543 { 1544 blk_trace_synthesize_old_trace(iter); 1545 1546 return trace_handle_return(&iter->seq); 1547 } 1548 1549 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1550 { 1551 if ((iter->ent->type != TRACE_BLK) || 1552 !(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1553 return TRACE_TYPE_UNHANDLED; 1554 1555 return print_one_line(iter, true); 1556 } 1557 1558 static int 1559 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) 1560 { 1561 /* don't output context-info for blk_classic output */ 1562 if (bit == TRACE_BLK_OPT_CLASSIC) { 1563 if (set) 1564 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1565 else 1566 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO; 1567 } 1568 return 0; 1569 } 1570 1571 static struct tracer blk_tracer __read_mostly = { 1572 .name = "blk", 1573 .init = blk_tracer_init, 1574 .reset = blk_tracer_reset, 1575 .start = blk_tracer_start, 1576 .stop = blk_tracer_stop, 1577 .print_header = blk_tracer_print_header, 1578 .print_line = blk_tracer_print_line, 1579 .flags = &blk_tracer_flags, 1580 .set_flag = blk_tracer_set_flag, 1581 }; 1582 1583 static struct trace_event_functions trace_blk_event_funcs = { 1584 .trace = blk_trace_event_print, 1585 .binary = blk_trace_event_print_binary, 1586 }; 1587 1588 static struct trace_event trace_blk_event = { 1589 .type = TRACE_BLK, 1590 .funcs = &trace_blk_event_funcs, 1591 }; 1592 1593 static int __init init_blk_tracer(void) 1594 { 1595 if (!register_trace_event(&trace_blk_event)) { 1596 pr_warn("Warning: could not register block events\n"); 1597 return 1; 1598 } 1599 1600 if (register_tracer(&blk_tracer) != 0) { 1601 pr_warn("Warning: could not register the block tracer\n"); 1602 unregister_trace_event(&trace_blk_event); 1603 return 1; 1604 } 1605 1606 return 0; 1607 } 1608 1609 device_initcall(init_blk_tracer); 1610 1611 static int blk_trace_remove_queue(struct request_queue *q) 1612 { 1613 struct blk_trace *bt; 1614 1615 bt = rcu_replace_pointer(q->blk_trace, NULL, 1616 lockdep_is_held(&q->debugfs_mutex)); 1617 if (bt == NULL) 1618 return -EINVAL; 1619 1620 blk_trace_stop(bt); 1621 1622 put_probe_ref(); 1623 synchronize_rcu(); 1624 blk_trace_free(q, bt); 1625 return 0; 1626 } 1627 1628 /* 1629 * Setup everything required to start tracing 1630 */ 1631 static int blk_trace_setup_queue(struct request_queue *q, 1632 struct block_device *bdev) 1633 { 1634 struct blk_trace *bt = NULL; 1635 int ret = -ENOMEM; 1636 1637 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1638 if (!bt) 1639 return -ENOMEM; 1640 1641 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1642 if (!bt->msg_data) 1643 goto free_bt; 1644 1645 bt->dev = bdev->bd_dev; 1646 bt->act_mask = (u16)-1; 1647 1648 blk_trace_setup_lba(bt, bdev); 1649 1650 rcu_assign_pointer(q->blk_trace, bt); 1651 get_probe_ref(); 1652 return 0; 1653 1654 free_bt: 1655 blk_trace_free(q, bt); 1656 return ret; 1657 } 1658 1659 /* 1660 * sysfs interface to enable and configure tracing 1661 */ 1662 1663 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1664 struct device_attribute *attr, 1665 char *buf); 1666 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1667 struct device_attribute *attr, 1668 const char *buf, size_t count); 1669 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1670 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1671 sysfs_blk_trace_attr_show, \ 1672 sysfs_blk_trace_attr_store) 1673 1674 static BLK_TRACE_DEVICE_ATTR(enable); 1675 static BLK_TRACE_DEVICE_ATTR(act_mask); 1676 static BLK_TRACE_DEVICE_ATTR(pid); 1677 static BLK_TRACE_DEVICE_ATTR(start_lba); 1678 static BLK_TRACE_DEVICE_ATTR(end_lba); 1679 1680 static struct attribute *blk_trace_attrs[] = { 1681 &dev_attr_enable.attr, 1682 &dev_attr_act_mask.attr, 1683 &dev_attr_pid.attr, 1684 &dev_attr_start_lba.attr, 1685 &dev_attr_end_lba.attr, 1686 NULL 1687 }; 1688 1689 struct attribute_group blk_trace_attr_group = { 1690 .name = "trace", 1691 .attrs = blk_trace_attrs, 1692 }; 1693 1694 static const struct { 1695 int mask; 1696 const char *str; 1697 } mask_maps[] = { 1698 { BLK_TC_READ, "read" }, 1699 { BLK_TC_WRITE, "write" }, 1700 { BLK_TC_FLUSH, "flush" }, 1701 { BLK_TC_SYNC, "sync" }, 1702 { BLK_TC_QUEUE, "queue" }, 1703 { BLK_TC_REQUEUE, "requeue" }, 1704 { BLK_TC_ISSUE, "issue" }, 1705 { BLK_TC_COMPLETE, "complete" }, 1706 { BLK_TC_FS, "fs" }, 1707 { BLK_TC_PC, "pc" }, 1708 { BLK_TC_NOTIFY, "notify" }, 1709 { BLK_TC_AHEAD, "ahead" }, 1710 { BLK_TC_META, "meta" }, 1711 { BLK_TC_DISCARD, "discard" }, 1712 { BLK_TC_DRV_DATA, "drv_data" }, 1713 { BLK_TC_FUA, "fua" }, 1714 }; 1715 1716 static int blk_trace_str2mask(const char *str) 1717 { 1718 int i; 1719 int mask = 0; 1720 char *buf, *s, *token; 1721 1722 buf = kstrdup(str, GFP_KERNEL); 1723 if (buf == NULL) 1724 return -ENOMEM; 1725 s = strstrip(buf); 1726 1727 while (1) { 1728 token = strsep(&s, ","); 1729 if (token == NULL) 1730 break; 1731 1732 if (*token == '\0') 1733 continue; 1734 1735 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1736 if (strcasecmp(token, mask_maps[i].str) == 0) { 1737 mask |= mask_maps[i].mask; 1738 break; 1739 } 1740 } 1741 if (i == ARRAY_SIZE(mask_maps)) { 1742 mask = -EINVAL; 1743 break; 1744 } 1745 } 1746 kfree(buf); 1747 1748 return mask; 1749 } 1750 1751 static ssize_t blk_trace_mask2str(char *buf, int mask) 1752 { 1753 int i; 1754 char *p = buf; 1755 1756 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1757 if (mask & mask_maps[i].mask) { 1758 p += sprintf(p, "%s%s", 1759 (p == buf) ? "" : ",", mask_maps[i].str); 1760 } 1761 } 1762 *p++ = '\n'; 1763 1764 return p - buf; 1765 } 1766 1767 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1768 struct device_attribute *attr, 1769 char *buf) 1770 { 1771 struct block_device *bdev = dev_to_bdev(dev); 1772 struct request_queue *q = bdev_get_queue(bdev); 1773 struct blk_trace *bt; 1774 ssize_t ret = -ENXIO; 1775 1776 mutex_lock(&q->debugfs_mutex); 1777 1778 bt = rcu_dereference_protected(q->blk_trace, 1779 lockdep_is_held(&q->debugfs_mutex)); 1780 if (attr == &dev_attr_enable) { 1781 ret = sprintf(buf, "%u\n", !!bt); 1782 goto out_unlock_bdev; 1783 } 1784 1785 if (bt == NULL) 1786 ret = sprintf(buf, "disabled\n"); 1787 else if (attr == &dev_attr_act_mask) 1788 ret = blk_trace_mask2str(buf, bt->act_mask); 1789 else if (attr == &dev_attr_pid) 1790 ret = sprintf(buf, "%u\n", bt->pid); 1791 else if (attr == &dev_attr_start_lba) 1792 ret = sprintf(buf, "%llu\n", bt->start_lba); 1793 else if (attr == &dev_attr_end_lba) 1794 ret = sprintf(buf, "%llu\n", bt->end_lba); 1795 1796 out_unlock_bdev: 1797 mutex_unlock(&q->debugfs_mutex); 1798 return ret; 1799 } 1800 1801 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1802 struct device_attribute *attr, 1803 const char *buf, size_t count) 1804 { 1805 struct block_device *bdev = dev_to_bdev(dev); 1806 struct request_queue *q = bdev_get_queue(bdev); 1807 struct blk_trace *bt; 1808 u64 value; 1809 ssize_t ret = -EINVAL; 1810 1811 if (count == 0) 1812 goto out; 1813 1814 if (attr == &dev_attr_act_mask) { 1815 if (kstrtoull(buf, 0, &value)) { 1816 /* Assume it is a list of trace category names */ 1817 ret = blk_trace_str2mask(buf); 1818 if (ret < 0) 1819 goto out; 1820 value = ret; 1821 } 1822 } else { 1823 if (kstrtoull(buf, 0, &value)) 1824 goto out; 1825 } 1826 1827 mutex_lock(&q->debugfs_mutex); 1828 1829 bt = rcu_dereference_protected(q->blk_trace, 1830 lockdep_is_held(&q->debugfs_mutex)); 1831 if (attr == &dev_attr_enable) { 1832 if (!!value == !!bt) { 1833 ret = 0; 1834 goto out_unlock_bdev; 1835 } 1836 if (value) 1837 ret = blk_trace_setup_queue(q, bdev); 1838 else 1839 ret = blk_trace_remove_queue(q); 1840 goto out_unlock_bdev; 1841 } 1842 1843 ret = 0; 1844 if (bt == NULL) { 1845 ret = blk_trace_setup_queue(q, bdev); 1846 bt = rcu_dereference_protected(q->blk_trace, 1847 lockdep_is_held(&q->debugfs_mutex)); 1848 } 1849 1850 if (ret == 0) { 1851 if (attr == &dev_attr_act_mask) 1852 bt->act_mask = value; 1853 else if (attr == &dev_attr_pid) 1854 bt->pid = value; 1855 else if (attr == &dev_attr_start_lba) 1856 bt->start_lba = value; 1857 else if (attr == &dev_attr_end_lba) 1858 bt->end_lba = value; 1859 } 1860 1861 out_unlock_bdev: 1862 mutex_unlock(&q->debugfs_mutex); 1863 out: 1864 return ret ? ret : count; 1865 } 1866 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1867 1868 #ifdef CONFIG_EVENT_TRACING 1869 1870 /** 1871 * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string. 1872 * @rwbs: buffer to be filled 1873 * @opf: request operation type (REQ_OP_XXX) and flags for the tracepoint 1874 * 1875 * Description: 1876 * Maps each request operation and flag to a single character and fills the 1877 * buffer provided by the caller with resulting string. 1878 * 1879 **/ 1880 void blk_fill_rwbs(char *rwbs, blk_opf_t opf) 1881 { 1882 int i = 0; 1883 1884 if (opf & REQ_PREFLUSH) 1885 rwbs[i++] = 'F'; 1886 1887 switch (opf & REQ_OP_MASK) { 1888 case REQ_OP_WRITE: 1889 rwbs[i++] = 'W'; 1890 break; 1891 case REQ_OP_DISCARD: 1892 rwbs[i++] = 'D'; 1893 break; 1894 case REQ_OP_SECURE_ERASE: 1895 rwbs[i++] = 'D'; 1896 rwbs[i++] = 'E'; 1897 break; 1898 case REQ_OP_FLUSH: 1899 rwbs[i++] = 'F'; 1900 break; 1901 case REQ_OP_READ: 1902 rwbs[i++] = 'R'; 1903 break; 1904 default: 1905 rwbs[i++] = 'N'; 1906 } 1907 1908 if (opf & REQ_FUA) 1909 rwbs[i++] = 'F'; 1910 if (opf & REQ_RAHEAD) 1911 rwbs[i++] = 'A'; 1912 if (opf & REQ_SYNC) 1913 rwbs[i++] = 'S'; 1914 if (opf & REQ_META) 1915 rwbs[i++] = 'M'; 1916 1917 rwbs[i] = '\0'; 1918 } 1919 EXPORT_SYMBOL_GPL(blk_fill_rwbs); 1920 1921 #endif /* CONFIG_EVENT_TRACING */ 1922 1923