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_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 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 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 __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg, 149 const char *fmt, ...) 150 { 151 int n; 152 va_list args; 153 unsigned long flags; 154 char *buf; 155 156 if (unlikely(bt->trace_state != Blktrace_running && 157 !blk_tracer_enabled)) 158 return; 159 160 /* 161 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note 162 * message to the trace. 163 */ 164 if (!(bt->act_mask & BLK_TC_NOTIFY)) 165 return; 166 167 local_irq_save(flags); 168 buf = this_cpu_ptr(bt->msg_data); 169 va_start(args, fmt); 170 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 171 va_end(args); 172 173 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP)) 174 blkcg = NULL; 175 #ifdef CONFIG_BLK_CGROUP 176 trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n, 177 blkcg ? cgroup_id(blkcg->css.cgroup) : 1); 178 #else 179 trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n, 0); 180 #endif 181 local_irq_restore(flags); 182 } 183 EXPORT_SYMBOL_GPL(__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) ((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 int op, int op_flags, u32 what, int error, int pdu_len, 217 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; 230 231 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 232 return; 233 234 what |= ddir_act[op_is_write(op) ? WRITE : READ]; 235 what |= MASK_TC_BIT(op_flags, SYNC); 236 what |= MASK_TC_BIT(op_flags, RAHEAD); 237 what |= MASK_TC_BIT(op_flags, META); 238 what |= MASK_TC_BIT(op_flags, PREFLUSH); 239 what |= MASK_TC_BIT(op_flags, FUA); 240 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE) 241 what |= BLK_TC_ACT(BLK_TC_DISCARD); 242 if (op == REQ_OP_FLUSH) 243 what |= BLK_TC_ACT(BLK_TC_FLUSH); 244 if (cgid) 245 what |= __BLK_TA_CGROUP; 246 247 pid = tsk->pid; 248 if (act_log_check(bt, what, sector, pid)) 249 return; 250 cpu = raw_smp_processor_id(); 251 252 if (blk_tracer) { 253 tracing_record_cmdline(current); 254 255 buffer = blk_tr->array_buffer.buffer; 256 trace_ctx = tracing_gen_ctx_flags(0); 257 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 258 sizeof(*t) + pdu_len + cgid_len, 259 trace_ctx); 260 if (!event) 261 return; 262 t = ring_buffer_event_data(event); 263 goto record_it; 264 } 265 266 if (unlikely(tsk->btrace_seq != blktrace_seq)) 267 trace_note_tsk(tsk); 268 269 /* 270 * A word about the locking here - we disable interrupts to reserve 271 * some space in the relay per-cpu buffer, to prevent an irq 272 * from coming in and stepping on our toes. 273 */ 274 local_irq_save(flags); 275 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len); 276 if (t) { 277 sequence = per_cpu_ptr(bt->sequence, cpu); 278 279 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 280 t->sequence = ++(*sequence); 281 t->time = ktime_to_ns(ktime_get()); 282 record_it: 283 /* 284 * These two are not needed in ftrace as they are in the 285 * generic trace_entry, filled by tracing_generic_entry_update, 286 * but for the trace_event->bin() synthesizer benefit we do it 287 * here too. 288 */ 289 t->cpu = cpu; 290 t->pid = pid; 291 292 t->sector = sector; 293 t->bytes = bytes; 294 t->action = what; 295 t->device = bt->dev; 296 t->error = error; 297 t->pdu_len = pdu_len + cgid_len; 298 299 if (cgid_len) 300 memcpy((void *)t + sizeof(*t), &cgid, cgid_len); 301 if (pdu_len) 302 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len); 303 304 if (blk_tracer) { 305 trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx); 306 return; 307 } 308 } 309 310 local_irq_restore(flags); 311 } 312 313 static void blk_trace_free(struct blk_trace *bt) 314 { 315 relay_close(bt->rchan); 316 debugfs_remove(bt->dir); 317 free_percpu(bt->sequence); 318 free_percpu(bt->msg_data); 319 kfree(bt); 320 } 321 322 static void get_probe_ref(void) 323 { 324 mutex_lock(&blk_probe_mutex); 325 if (++blk_probes_ref == 1) 326 blk_register_tracepoints(); 327 mutex_unlock(&blk_probe_mutex); 328 } 329 330 static void put_probe_ref(void) 331 { 332 mutex_lock(&blk_probe_mutex); 333 if (!--blk_probes_ref) 334 blk_unregister_tracepoints(); 335 mutex_unlock(&blk_probe_mutex); 336 } 337 338 static void blk_trace_cleanup(struct blk_trace *bt) 339 { 340 synchronize_rcu(); 341 blk_trace_free(bt); 342 put_probe_ref(); 343 } 344 345 static int __blk_trace_remove(struct request_queue *q) 346 { 347 struct blk_trace *bt; 348 349 bt = rcu_replace_pointer(q->blk_trace, NULL, 350 lockdep_is_held(&q->debugfs_mutex)); 351 if (!bt) 352 return -EINVAL; 353 354 if (bt->trace_state != Blktrace_running) 355 blk_trace_cleanup(bt); 356 357 return 0; 358 } 359 360 int blk_trace_remove(struct request_queue *q) 361 { 362 int ret; 363 364 mutex_lock(&q->debugfs_mutex); 365 ret = __blk_trace_remove(q); 366 mutex_unlock(&q->debugfs_mutex); 367 368 return ret; 369 } 370 EXPORT_SYMBOL_GPL(blk_trace_remove); 371 372 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 373 size_t count, loff_t *ppos) 374 { 375 struct blk_trace *bt = filp->private_data; 376 char buf[16]; 377 378 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 379 380 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 381 } 382 383 static const struct file_operations blk_dropped_fops = { 384 .owner = THIS_MODULE, 385 .open = simple_open, 386 .read = blk_dropped_read, 387 .llseek = default_llseek, 388 }; 389 390 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 391 size_t count, loff_t *ppos) 392 { 393 char *msg; 394 struct blk_trace *bt; 395 396 if (count >= BLK_TN_MAX_MSG) 397 return -EINVAL; 398 399 msg = memdup_user_nul(buffer, count); 400 if (IS_ERR(msg)) 401 return PTR_ERR(msg); 402 403 bt = filp->private_data; 404 __trace_note_message(bt, NULL, "%s", msg); 405 kfree(msg); 406 407 return count; 408 } 409 410 static const struct file_operations blk_msg_fops = { 411 .owner = THIS_MODULE, 412 .open = simple_open, 413 .write = blk_msg_write, 414 .llseek = noop_llseek, 415 }; 416 417 /* 418 * Keep track of how many times we encountered a full subbuffer, to aid 419 * the user space app in telling how many lost events there were. 420 */ 421 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 422 void *prev_subbuf, size_t prev_padding) 423 { 424 struct blk_trace *bt; 425 426 if (!relay_buf_full(buf)) 427 return 1; 428 429 bt = buf->chan->private_data; 430 atomic_inc(&bt->dropped); 431 return 0; 432 } 433 434 static int blk_remove_buf_file_callback(struct dentry *dentry) 435 { 436 debugfs_remove(dentry); 437 438 return 0; 439 } 440 441 static struct dentry *blk_create_buf_file_callback(const char *filename, 442 struct dentry *parent, 443 umode_t mode, 444 struct rchan_buf *buf, 445 int *is_global) 446 { 447 return debugfs_create_file(filename, mode, parent, buf, 448 &relay_file_operations); 449 } 450 451 static const struct rchan_callbacks blk_relay_callbacks = { 452 .subbuf_start = blk_subbuf_start_callback, 453 .create_buf_file = blk_create_buf_file_callback, 454 .remove_buf_file = blk_remove_buf_file_callback, 455 }; 456 457 static void blk_trace_setup_lba(struct blk_trace *bt, 458 struct block_device *bdev) 459 { 460 if (bdev) { 461 bt->start_lba = bdev->bd_start_sect; 462 bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev); 463 } else { 464 bt->start_lba = 0; 465 bt->end_lba = -1ULL; 466 } 467 } 468 469 /* 470 * Setup everything required to start tracing 471 */ 472 static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 473 struct block_device *bdev, 474 struct blk_user_trace_setup *buts) 475 { 476 struct blk_trace *bt = NULL; 477 struct dentry *dir = NULL; 478 int ret; 479 480 lockdep_assert_held(&q->debugfs_mutex); 481 482 if (!buts->buf_size || !buts->buf_nr) 483 return -EINVAL; 484 485 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 486 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 487 488 /* 489 * some device names have larger paths - convert the slashes 490 * to underscores for this to work as expected 491 */ 492 strreplace(buts->name, '/', '_'); 493 494 /* 495 * bdev can be NULL, as with scsi-generic, this is a helpful as 496 * we can be. 497 */ 498 if (rcu_dereference_protected(q->blk_trace, 499 lockdep_is_held(&q->debugfs_mutex))) { 500 pr_warn("Concurrent blktraces are not allowed on %s\n", 501 buts->name); 502 return -EBUSY; 503 } 504 505 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 506 if (!bt) 507 return -ENOMEM; 508 509 ret = -ENOMEM; 510 bt->sequence = alloc_percpu(unsigned long); 511 if (!bt->sequence) 512 goto err; 513 514 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 515 if (!bt->msg_data) 516 goto err; 517 518 /* 519 * When tracing the whole disk reuse the existing debugfs directory 520 * created by the block layer on init. For partitions block devices, 521 * and scsi-generic block devices we create a temporary new debugfs 522 * directory that will be removed once the trace ends. 523 */ 524 if (bdev && !bdev_is_partition(bdev)) 525 dir = q->debugfs_dir; 526 else 527 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root); 528 529 /* 530 * As blktrace relies on debugfs for its interface the debugfs directory 531 * is required, contrary to the usual mantra of not checking for debugfs 532 * files or directories. 533 */ 534 if (IS_ERR_OR_NULL(dir)) { 535 pr_warn("debugfs_dir not present for %s so skipping\n", 536 buts->name); 537 ret = -ENOENT; 538 goto err; 539 } 540 541 bt->dev = dev; 542 atomic_set(&bt->dropped, 0); 543 INIT_LIST_HEAD(&bt->running_list); 544 545 ret = -EIO; 546 debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops); 547 debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 548 549 bt->rchan = relay_open("trace", dir, buts->buf_size, 550 buts->buf_nr, &blk_relay_callbacks, bt); 551 if (!bt->rchan) 552 goto err; 553 554 bt->act_mask = buts->act_mask; 555 if (!bt->act_mask) 556 bt->act_mask = (u16) -1; 557 558 blk_trace_setup_lba(bt, bdev); 559 560 /* overwrite with user settings */ 561 if (buts->start_lba) 562 bt->start_lba = buts->start_lba; 563 if (buts->end_lba) 564 bt->end_lba = buts->end_lba; 565 566 bt->pid = buts->pid; 567 bt->trace_state = Blktrace_setup; 568 569 rcu_assign_pointer(q->blk_trace, bt); 570 get_probe_ref(); 571 572 ret = 0; 573 err: 574 if (ret) 575 blk_trace_free(bt); 576 return ret; 577 } 578 579 static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 580 struct block_device *bdev, char __user *arg) 581 { 582 struct blk_user_trace_setup buts; 583 int ret; 584 585 ret = copy_from_user(&buts, arg, sizeof(buts)); 586 if (ret) 587 return -EFAULT; 588 589 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 590 if (ret) 591 return ret; 592 593 if (copy_to_user(arg, &buts, sizeof(buts))) { 594 __blk_trace_remove(q); 595 return -EFAULT; 596 } 597 return 0; 598 } 599 600 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 601 struct block_device *bdev, 602 char __user *arg) 603 { 604 int ret; 605 606 mutex_lock(&q->debugfs_mutex); 607 ret = __blk_trace_setup(q, name, dev, bdev, arg); 608 mutex_unlock(&q->debugfs_mutex); 609 610 return ret; 611 } 612 EXPORT_SYMBOL_GPL(blk_trace_setup); 613 614 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 615 static int compat_blk_trace_setup(struct request_queue *q, char *name, 616 dev_t dev, struct block_device *bdev, 617 char __user *arg) 618 { 619 struct blk_user_trace_setup buts; 620 struct compat_blk_user_trace_setup cbuts; 621 int ret; 622 623 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 624 return -EFAULT; 625 626 buts = (struct blk_user_trace_setup) { 627 .act_mask = cbuts.act_mask, 628 .buf_size = cbuts.buf_size, 629 .buf_nr = cbuts.buf_nr, 630 .start_lba = cbuts.start_lba, 631 .end_lba = cbuts.end_lba, 632 .pid = cbuts.pid, 633 }; 634 635 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 636 if (ret) 637 return ret; 638 639 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) { 640 __blk_trace_remove(q); 641 return -EFAULT; 642 } 643 644 return 0; 645 } 646 #endif 647 648 static int __blk_trace_startstop(struct request_queue *q, int start) 649 { 650 int ret; 651 struct blk_trace *bt; 652 653 bt = rcu_dereference_protected(q->blk_trace, 654 lockdep_is_held(&q->debugfs_mutex)); 655 if (bt == NULL) 656 return -EINVAL; 657 658 /* 659 * For starting a trace, we can transition from a setup or stopped 660 * trace. For stopping a trace, the state must be running 661 */ 662 ret = -EINVAL; 663 if (start) { 664 if (bt->trace_state == Blktrace_setup || 665 bt->trace_state == Blktrace_stopped) { 666 blktrace_seq++; 667 smp_mb(); 668 bt->trace_state = Blktrace_running; 669 spin_lock_irq(&running_trace_lock); 670 list_add(&bt->running_list, &running_trace_list); 671 spin_unlock_irq(&running_trace_lock); 672 673 trace_note_time(bt); 674 ret = 0; 675 } 676 } else { 677 if (bt->trace_state == Blktrace_running) { 678 bt->trace_state = Blktrace_stopped; 679 spin_lock_irq(&running_trace_lock); 680 list_del_init(&bt->running_list); 681 spin_unlock_irq(&running_trace_lock); 682 relay_flush(bt->rchan); 683 ret = 0; 684 } 685 } 686 687 return ret; 688 } 689 690 int blk_trace_startstop(struct request_queue *q, int start) 691 { 692 int ret; 693 694 mutex_lock(&q->debugfs_mutex); 695 ret = __blk_trace_startstop(q, start); 696 mutex_unlock(&q->debugfs_mutex); 697 698 return ret; 699 } 700 EXPORT_SYMBOL_GPL(blk_trace_startstop); 701 702 /* 703 * When reading or writing the blktrace sysfs files, the references to the 704 * opened sysfs or device files should prevent the underlying block device 705 * from being removed. So no further delete protection is really needed. 706 */ 707 708 /** 709 * blk_trace_ioctl: - handle the ioctls associated with tracing 710 * @bdev: the block device 711 * @cmd: the ioctl cmd 712 * @arg: the argument data, if any 713 * 714 **/ 715 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 716 { 717 struct request_queue *q; 718 int ret, start = 0; 719 char b[BDEVNAME_SIZE]; 720 721 q = bdev_get_queue(bdev); 722 if (!q) 723 return -ENXIO; 724 725 mutex_lock(&q->debugfs_mutex); 726 727 switch (cmd) { 728 case BLKTRACESETUP: 729 bdevname(bdev, b); 730 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 731 break; 732 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 733 case BLKTRACESETUP32: 734 bdevname(bdev, b); 735 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 736 break; 737 #endif 738 case BLKTRACESTART: 739 start = 1; 740 fallthrough; 741 case BLKTRACESTOP: 742 ret = __blk_trace_startstop(q, start); 743 break; 744 case BLKTRACETEARDOWN: 745 ret = __blk_trace_remove(q); 746 break; 747 default: 748 ret = -ENOTTY; 749 break; 750 } 751 752 mutex_unlock(&q->debugfs_mutex); 753 return ret; 754 } 755 756 /** 757 * blk_trace_shutdown: - stop and cleanup trace structures 758 * @q: the request queue associated with the device 759 * 760 **/ 761 void blk_trace_shutdown(struct request_queue *q) 762 { 763 mutex_lock(&q->debugfs_mutex); 764 if (rcu_dereference_protected(q->blk_trace, 765 lockdep_is_held(&q->debugfs_mutex))) { 766 __blk_trace_startstop(q, 0); 767 __blk_trace_remove(q); 768 } 769 770 mutex_unlock(&q->debugfs_mutex); 771 } 772 773 #ifdef CONFIG_BLK_CGROUP 774 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) 775 { 776 struct blk_trace *bt; 777 778 /* We don't use the 'bt' value here except as an optimization... */ 779 bt = rcu_dereference_protected(q->blk_trace, 1); 780 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP)) 781 return 0; 782 783 if (!bio->bi_blkg) 784 return 0; 785 return cgroup_id(bio_blkcg(bio)->css.cgroup); 786 } 787 #else 788 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) 789 { 790 return 0; 791 } 792 #endif 793 794 static u64 795 blk_trace_request_get_cgid(struct request *rq) 796 { 797 if (!rq->bio) 798 return 0; 799 /* Use the first bio */ 800 return blk_trace_bio_get_cgid(rq->q, rq->bio); 801 } 802 803 /* 804 * blktrace probes 805 */ 806 807 /** 808 * blk_add_trace_rq - Add a trace for a request oriented action 809 * @rq: the source request 810 * @error: return status to log 811 * @nr_bytes: number of completed bytes 812 * @what: the action 813 * @cgid: the cgroup info 814 * 815 * Description: 816 * Records an action against a request. Will log the bio offset + size. 817 * 818 **/ 819 static void blk_add_trace_rq(struct request *rq, int error, 820 unsigned int nr_bytes, u32 what, u64 cgid) 821 { 822 struct blk_trace *bt; 823 824 rcu_read_lock(); 825 bt = rcu_dereference(rq->q->blk_trace); 826 if (likely(!bt)) { 827 rcu_read_unlock(); 828 return; 829 } 830 831 if (blk_rq_is_passthrough(rq)) 832 what |= BLK_TC_ACT(BLK_TC_PC); 833 else 834 what |= BLK_TC_ACT(BLK_TC_FS); 835 836 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq), 837 rq->cmd_flags, what, error, 0, NULL, cgid); 838 rcu_read_unlock(); 839 } 840 841 static void blk_add_trace_rq_insert(void *ignore, struct request *rq) 842 { 843 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT, 844 blk_trace_request_get_cgid(rq)); 845 } 846 847 static void blk_add_trace_rq_issue(void *ignore, struct request *rq) 848 { 849 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE, 850 blk_trace_request_get_cgid(rq)); 851 } 852 853 static void blk_add_trace_rq_merge(void *ignore, struct request *rq) 854 { 855 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE, 856 blk_trace_request_get_cgid(rq)); 857 } 858 859 static void blk_add_trace_rq_requeue(void *ignore, struct request *rq) 860 { 861 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE, 862 blk_trace_request_get_cgid(rq)); 863 } 864 865 static void blk_add_trace_rq_complete(void *ignore, struct request *rq, 866 int error, unsigned int nr_bytes) 867 { 868 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE, 869 blk_trace_request_get_cgid(rq)); 870 } 871 872 /** 873 * blk_add_trace_bio - Add a trace for a bio oriented action 874 * @q: queue the io is for 875 * @bio: the source bio 876 * @what: the action 877 * @error: error, if any 878 * 879 * Description: 880 * Records an action against a bio. Will log the bio offset + size. 881 * 882 **/ 883 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 884 u32 what, int error) 885 { 886 struct blk_trace *bt; 887 888 rcu_read_lock(); 889 bt = rcu_dereference(q->blk_trace); 890 if (likely(!bt)) { 891 rcu_read_unlock(); 892 return; 893 } 894 895 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 896 bio_op(bio), bio->bi_opf, what, error, 0, NULL, 897 blk_trace_bio_get_cgid(q, bio)); 898 rcu_read_unlock(); 899 } 900 901 static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio) 902 { 903 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0); 904 } 905 906 static void blk_add_trace_bio_complete(void *ignore, 907 struct request_queue *q, struct bio *bio) 908 { 909 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, 910 blk_status_to_errno(bio->bi_status)); 911 } 912 913 static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio) 914 { 915 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE, 916 0); 917 } 918 919 static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio) 920 { 921 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE, 922 0); 923 } 924 925 static void blk_add_trace_bio_queue(void *ignore, struct bio *bio) 926 { 927 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0); 928 } 929 930 static void blk_add_trace_getrq(void *ignore, struct bio *bio) 931 { 932 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0); 933 } 934 935 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 936 { 937 struct blk_trace *bt; 938 939 rcu_read_lock(); 940 bt = rcu_dereference(q->blk_trace); 941 if (bt) 942 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0); 943 rcu_read_unlock(); 944 } 945 946 static void blk_add_trace_unplug(void *ignore, struct request_queue *q, 947 unsigned int depth, bool explicit) 948 { 949 struct blk_trace *bt; 950 951 rcu_read_lock(); 952 bt = rcu_dereference(q->blk_trace); 953 if (bt) { 954 __be64 rpdu = cpu_to_be64(depth); 955 u32 what; 956 957 if (explicit) 958 what = BLK_TA_UNPLUG_IO; 959 else 960 what = BLK_TA_UNPLUG_TIMER; 961 962 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0); 963 } 964 rcu_read_unlock(); 965 } 966 967 static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu) 968 { 969 struct request_queue *q = bio->bi_bdev->bd_disk->queue; 970 struct blk_trace *bt; 971 972 rcu_read_lock(); 973 bt = rcu_dereference(q->blk_trace); 974 if (bt) { 975 __be64 rpdu = cpu_to_be64(pdu); 976 977 __blk_add_trace(bt, bio->bi_iter.bi_sector, 978 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf, 979 BLK_TA_SPLIT, 980 blk_status_to_errno(bio->bi_status), 981 sizeof(rpdu), &rpdu, 982 blk_trace_bio_get_cgid(q, bio)); 983 } 984 rcu_read_unlock(); 985 } 986 987 /** 988 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation 989 * @ignore: trace callback data parameter (not used) 990 * @bio: the source bio 991 * @dev: source device 992 * @from: source sector 993 * 994 * Called after a bio is remapped to a different device and/or sector. 995 **/ 996 static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev, 997 sector_t from) 998 { 999 struct request_queue *q = bio->bi_bdev->bd_disk->queue; 1000 struct blk_trace *bt; 1001 struct blk_io_trace_remap r; 1002 1003 rcu_read_lock(); 1004 bt = rcu_dereference(q->blk_trace); 1005 if (likely(!bt)) { 1006 rcu_read_unlock(); 1007 return; 1008 } 1009 1010 r.device_from = cpu_to_be32(dev); 1011 r.device_to = cpu_to_be32(bio_dev(bio)); 1012 r.sector_from = cpu_to_be64(from); 1013 1014 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 1015 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, 1016 blk_status_to_errno(bio->bi_status), 1017 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio)); 1018 rcu_read_unlock(); 1019 } 1020 1021 /** 1022 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 1023 * @ignore: trace callback data parameter (not used) 1024 * @rq: the source request 1025 * @dev: target device 1026 * @from: source sector 1027 * 1028 * Description: 1029 * Device mapper remaps request to other devices. 1030 * Add a trace for that action. 1031 * 1032 **/ 1033 static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev, 1034 sector_t from) 1035 { 1036 struct blk_trace *bt; 1037 struct blk_io_trace_remap r; 1038 1039 rcu_read_lock(); 1040 bt = rcu_dereference(rq->q->blk_trace); 1041 if (likely(!bt)) { 1042 rcu_read_unlock(); 1043 return; 1044 } 1045 1046 r.device_from = cpu_to_be32(dev); 1047 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 1048 r.sector_from = cpu_to_be64(from); 1049 1050 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 1051 rq_data_dir(rq), 0, BLK_TA_REMAP, 0, 1052 sizeof(r), &r, blk_trace_request_get_cgid(rq)); 1053 rcu_read_unlock(); 1054 } 1055 1056 /** 1057 * blk_add_driver_data - Add binary message with driver-specific data 1058 * @rq: io request 1059 * @data: driver-specific data 1060 * @len: length of driver-specific data 1061 * 1062 * Description: 1063 * Some drivers might want to write driver-specific data per request. 1064 * 1065 **/ 1066 void blk_add_driver_data(struct request *rq, void *data, size_t len) 1067 { 1068 struct blk_trace *bt; 1069 1070 rcu_read_lock(); 1071 bt = rcu_dereference(rq->q->blk_trace); 1072 if (likely(!bt)) { 1073 rcu_read_unlock(); 1074 return; 1075 } 1076 1077 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0, 1078 BLK_TA_DRV_DATA, 0, len, data, 1079 blk_trace_request_get_cgid(rq)); 1080 rcu_read_unlock(); 1081 } 1082 EXPORT_SYMBOL_GPL(blk_add_driver_data); 1083 1084 static void blk_register_tracepoints(void) 1085 { 1086 int ret; 1087 1088 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1089 WARN_ON(ret); 1090 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1091 WARN_ON(ret); 1092 ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL); 1093 WARN_ON(ret); 1094 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1095 WARN_ON(ret); 1096 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1097 WARN_ON(ret); 1098 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1099 WARN_ON(ret); 1100 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1101 WARN_ON(ret); 1102 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1103 WARN_ON(ret); 1104 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1105 WARN_ON(ret); 1106 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1107 WARN_ON(ret); 1108 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 1109 WARN_ON(ret); 1110 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 1111 WARN_ON(ret); 1112 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL); 1113 WARN_ON(ret); 1114 ret = register_trace_block_split(blk_add_trace_split, NULL); 1115 WARN_ON(ret); 1116 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1117 WARN_ON(ret); 1118 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1119 WARN_ON(ret); 1120 } 1121 1122 static void blk_unregister_tracepoints(void) 1123 { 1124 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1125 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1126 unregister_trace_block_split(blk_add_trace_split, NULL); 1127 unregister_trace_block_unplug(blk_add_trace_unplug, NULL); 1128 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1129 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1130 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1131 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1132 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1133 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1134 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1135 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1136 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1137 unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL); 1138 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1139 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1140 1141 tracepoint_synchronize_unregister(); 1142 } 1143 1144 /* 1145 * struct blk_io_tracer formatting routines 1146 */ 1147 1148 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1149 { 1150 int i = 0; 1151 int tc = t->action >> BLK_TC_SHIFT; 1152 1153 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { 1154 rwbs[i++] = 'N'; 1155 goto out; 1156 } 1157 1158 if (tc & BLK_TC_FLUSH) 1159 rwbs[i++] = 'F'; 1160 1161 if (tc & BLK_TC_DISCARD) 1162 rwbs[i++] = 'D'; 1163 else if (tc & BLK_TC_WRITE) 1164 rwbs[i++] = 'W'; 1165 else if (t->bytes) 1166 rwbs[i++] = 'R'; 1167 else 1168 rwbs[i++] = 'N'; 1169 1170 if (tc & BLK_TC_FUA) 1171 rwbs[i++] = 'F'; 1172 if (tc & BLK_TC_AHEAD) 1173 rwbs[i++] = 'A'; 1174 if (tc & BLK_TC_SYNC) 1175 rwbs[i++] = 'S'; 1176 if (tc & BLK_TC_META) 1177 rwbs[i++] = 'M'; 1178 out: 1179 rwbs[i] = '\0'; 1180 } 1181 1182 static inline 1183 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1184 { 1185 return (const struct blk_io_trace *)ent; 1186 } 1187 1188 static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg) 1189 { 1190 return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0); 1191 } 1192 1193 static inline u64 t_cgid(const struct trace_entry *ent) 1194 { 1195 return *(u64 *)(te_blk_io_trace(ent) + 1); 1196 } 1197 1198 static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg) 1199 { 1200 return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0); 1201 } 1202 1203 static inline u32 t_action(const struct trace_entry *ent) 1204 { 1205 return te_blk_io_trace(ent)->action; 1206 } 1207 1208 static inline u32 t_bytes(const struct trace_entry *ent) 1209 { 1210 return te_blk_io_trace(ent)->bytes; 1211 } 1212 1213 static inline u32 t_sec(const struct trace_entry *ent) 1214 { 1215 return te_blk_io_trace(ent)->bytes >> 9; 1216 } 1217 1218 static inline unsigned long long t_sector(const struct trace_entry *ent) 1219 { 1220 return te_blk_io_trace(ent)->sector; 1221 } 1222 1223 static inline __u16 t_error(const struct trace_entry *ent) 1224 { 1225 return te_blk_io_trace(ent)->error; 1226 } 1227 1228 static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg) 1229 { 1230 const __be64 *val = pdu_start(ent, has_cg); 1231 return be64_to_cpu(*val); 1232 } 1233 1234 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act, 1235 bool has_cg); 1236 1237 static void blk_log_action_classic(struct trace_iterator *iter, const char *act, 1238 bool has_cg) 1239 { 1240 char rwbs[RWBS_LEN]; 1241 unsigned long long ts = iter->ts; 1242 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1243 unsigned secs = (unsigned long)ts; 1244 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1245 1246 fill_rwbs(rwbs, t); 1247 1248 trace_seq_printf(&iter->seq, 1249 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1250 MAJOR(t->device), MINOR(t->device), iter->cpu, 1251 secs, nsec_rem, iter->ent->pid, act, rwbs); 1252 } 1253 1254 static void blk_log_action(struct trace_iterator *iter, const char *act, 1255 bool has_cg) 1256 { 1257 char rwbs[RWBS_LEN]; 1258 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1259 1260 fill_rwbs(rwbs, t); 1261 if (has_cg) { 1262 u64 id = t_cgid(iter->ent); 1263 1264 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) { 1265 char blkcg_name_buf[NAME_MAX + 1] = "<...>"; 1266 1267 cgroup_path_from_kernfs_id(id, blkcg_name_buf, 1268 sizeof(blkcg_name_buf)); 1269 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ", 1270 MAJOR(t->device), MINOR(t->device), 1271 blkcg_name_buf, act, rwbs); 1272 } else { 1273 /* 1274 * The cgid portion used to be "INO,GEN". Userland 1275 * builds a FILEID_INO32_GEN fid out of them and 1276 * opens the cgroup using open_by_handle_at(2). 1277 * While 32bit ino setups are still the same, 64bit 1278 * ones now use the 64bit ino as the whole ID and 1279 * no longer use generation. 1280 * 1281 * Regardless of the content, always output 1282 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can 1283 * be mapped back to @id on both 64 and 32bit ino 1284 * setups. See __kernfs_fh_to_dentry(). 1285 */ 1286 trace_seq_printf(&iter->seq, 1287 "%3d,%-3d %llx,%-llx %2s %3s ", 1288 MAJOR(t->device), MINOR(t->device), 1289 id & U32_MAX, id >> 32, act, rwbs); 1290 } 1291 } else 1292 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1293 MAJOR(t->device), MINOR(t->device), act, rwbs); 1294 } 1295 1296 static void blk_log_dump_pdu(struct trace_seq *s, 1297 const struct trace_entry *ent, bool has_cg) 1298 { 1299 const unsigned char *pdu_buf; 1300 int pdu_len; 1301 int i, end; 1302 1303 pdu_buf = pdu_start(ent, has_cg); 1304 pdu_len = pdu_real_len(ent, has_cg); 1305 1306 if (!pdu_len) 1307 return; 1308 1309 /* find the last zero that needs to be printed */ 1310 for (end = pdu_len - 1; end >= 0; end--) 1311 if (pdu_buf[end]) 1312 break; 1313 end++; 1314 1315 trace_seq_putc(s, '('); 1316 1317 for (i = 0; i < pdu_len; i++) { 1318 1319 trace_seq_printf(s, "%s%02x", 1320 i == 0 ? "" : " ", pdu_buf[i]); 1321 1322 /* 1323 * stop when the rest is just zeros and indicate so 1324 * with a ".." appended 1325 */ 1326 if (i == end && end != pdu_len - 1) { 1327 trace_seq_puts(s, " ..) "); 1328 return; 1329 } 1330 } 1331 1332 trace_seq_puts(s, ") "); 1333 } 1334 1335 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1336 { 1337 char cmd[TASK_COMM_LEN]; 1338 1339 trace_find_cmdline(ent->pid, cmd); 1340 1341 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1342 trace_seq_printf(s, "%u ", t_bytes(ent)); 1343 blk_log_dump_pdu(s, ent, has_cg); 1344 trace_seq_printf(s, "[%s]\n", cmd); 1345 } else { 1346 if (t_sec(ent)) 1347 trace_seq_printf(s, "%llu + %u [%s]\n", 1348 t_sector(ent), t_sec(ent), cmd); 1349 else 1350 trace_seq_printf(s, "[%s]\n", cmd); 1351 } 1352 } 1353 1354 static void blk_log_with_error(struct trace_seq *s, 1355 const struct trace_entry *ent, bool has_cg) 1356 { 1357 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1358 blk_log_dump_pdu(s, ent, has_cg); 1359 trace_seq_printf(s, "[%d]\n", t_error(ent)); 1360 } else { 1361 if (t_sec(ent)) 1362 trace_seq_printf(s, "%llu + %u [%d]\n", 1363 t_sector(ent), 1364 t_sec(ent), t_error(ent)); 1365 else 1366 trace_seq_printf(s, "%llu [%d]\n", 1367 t_sector(ent), t_error(ent)); 1368 } 1369 } 1370 1371 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1372 { 1373 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg); 1374 1375 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1376 t_sector(ent), t_sec(ent), 1377 MAJOR(be32_to_cpu(__r->device_from)), 1378 MINOR(be32_to_cpu(__r->device_from)), 1379 be64_to_cpu(__r->sector_from)); 1380 } 1381 1382 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1383 { 1384 char cmd[TASK_COMM_LEN]; 1385 1386 trace_find_cmdline(ent->pid, cmd); 1387 1388 trace_seq_printf(s, "[%s]\n", cmd); 1389 } 1390 1391 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1392 { 1393 char cmd[TASK_COMM_LEN]; 1394 1395 trace_find_cmdline(ent->pid, cmd); 1396 1397 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg)); 1398 } 1399 1400 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1401 { 1402 char cmd[TASK_COMM_LEN]; 1403 1404 trace_find_cmdline(ent->pid, cmd); 1405 1406 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1407 get_pdu_int(ent, has_cg), cmd); 1408 } 1409 1410 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent, 1411 bool has_cg) 1412 { 1413 1414 trace_seq_putmem(s, pdu_start(ent, has_cg), 1415 pdu_real_len(ent, has_cg)); 1416 trace_seq_putc(s, '\n'); 1417 } 1418 1419 /* 1420 * struct tracer operations 1421 */ 1422 1423 static void blk_tracer_print_header(struct seq_file *m) 1424 { 1425 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1426 return; 1427 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1428 "# | | | | | |\n"); 1429 } 1430 1431 static void blk_tracer_start(struct trace_array *tr) 1432 { 1433 blk_tracer_enabled = true; 1434 } 1435 1436 static int blk_tracer_init(struct trace_array *tr) 1437 { 1438 blk_tr = tr; 1439 blk_tracer_start(tr); 1440 return 0; 1441 } 1442 1443 static void blk_tracer_stop(struct trace_array *tr) 1444 { 1445 blk_tracer_enabled = false; 1446 } 1447 1448 static void blk_tracer_reset(struct trace_array *tr) 1449 { 1450 blk_tracer_stop(tr); 1451 } 1452 1453 static const struct { 1454 const char *act[2]; 1455 void (*print)(struct trace_seq *s, const struct trace_entry *ent, 1456 bool has_cg); 1457 } what2act[] = { 1458 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1459 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1460 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1461 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1462 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1463 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1464 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1465 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1466 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1467 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1468 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1469 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1470 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1471 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1472 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1473 }; 1474 1475 static enum print_line_t print_one_line(struct trace_iterator *iter, 1476 bool classic) 1477 { 1478 struct trace_array *tr = iter->tr; 1479 struct trace_seq *s = &iter->seq; 1480 const struct blk_io_trace *t; 1481 u16 what; 1482 bool long_act; 1483 blk_log_action_t *log_action; 1484 bool has_cg; 1485 1486 t = te_blk_io_trace(iter->ent); 1487 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP; 1488 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE); 1489 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1490 has_cg = t->action & __BLK_TA_CGROUP; 1491 1492 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { 1493 log_action(iter, long_act ? "message" : "m", has_cg); 1494 blk_log_msg(s, iter->ent, has_cg); 1495 return trace_handle_return(s); 1496 } 1497 1498 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1499 trace_seq_printf(s, "Unknown action %x\n", what); 1500 else { 1501 log_action(iter, what2act[what].act[long_act], has_cg); 1502 what2act[what].print(s, iter->ent, has_cg); 1503 } 1504 1505 return trace_handle_return(s); 1506 } 1507 1508 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1509 int flags, struct trace_event *event) 1510 { 1511 return print_one_line(iter, false); 1512 } 1513 1514 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1515 { 1516 struct trace_seq *s = &iter->seq; 1517 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1518 const int offset = offsetof(struct blk_io_trace, sector); 1519 struct blk_io_trace old = { 1520 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1521 .time = iter->ts, 1522 }; 1523 1524 trace_seq_putmem(s, &old, offset); 1525 trace_seq_putmem(s, &t->sector, 1526 sizeof(old) - offset + t->pdu_len); 1527 } 1528 1529 static enum print_line_t 1530 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1531 struct trace_event *event) 1532 { 1533 blk_trace_synthesize_old_trace(iter); 1534 1535 return trace_handle_return(&iter->seq); 1536 } 1537 1538 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1539 { 1540 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1541 return TRACE_TYPE_UNHANDLED; 1542 1543 return print_one_line(iter, true); 1544 } 1545 1546 static int 1547 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) 1548 { 1549 /* don't output context-info for blk_classic output */ 1550 if (bit == TRACE_BLK_OPT_CLASSIC) { 1551 if (set) 1552 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1553 else 1554 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO; 1555 } 1556 return 0; 1557 } 1558 1559 static struct tracer blk_tracer __read_mostly = { 1560 .name = "blk", 1561 .init = blk_tracer_init, 1562 .reset = blk_tracer_reset, 1563 .start = blk_tracer_start, 1564 .stop = blk_tracer_stop, 1565 .print_header = blk_tracer_print_header, 1566 .print_line = blk_tracer_print_line, 1567 .flags = &blk_tracer_flags, 1568 .set_flag = blk_tracer_set_flag, 1569 }; 1570 1571 static struct trace_event_functions trace_blk_event_funcs = { 1572 .trace = blk_trace_event_print, 1573 .binary = blk_trace_event_print_binary, 1574 }; 1575 1576 static struct trace_event trace_blk_event = { 1577 .type = TRACE_BLK, 1578 .funcs = &trace_blk_event_funcs, 1579 }; 1580 1581 static int __init init_blk_tracer(void) 1582 { 1583 if (!register_trace_event(&trace_blk_event)) { 1584 pr_warn("Warning: could not register block events\n"); 1585 return 1; 1586 } 1587 1588 if (register_tracer(&blk_tracer) != 0) { 1589 pr_warn("Warning: could not register the block tracer\n"); 1590 unregister_trace_event(&trace_blk_event); 1591 return 1; 1592 } 1593 1594 return 0; 1595 } 1596 1597 device_initcall(init_blk_tracer); 1598 1599 static int blk_trace_remove_queue(struct request_queue *q) 1600 { 1601 struct blk_trace *bt; 1602 1603 bt = rcu_replace_pointer(q->blk_trace, NULL, 1604 lockdep_is_held(&q->debugfs_mutex)); 1605 if (bt == NULL) 1606 return -EINVAL; 1607 1608 if (bt->trace_state == Blktrace_running) { 1609 bt->trace_state = Blktrace_stopped; 1610 spin_lock_irq(&running_trace_lock); 1611 list_del_init(&bt->running_list); 1612 spin_unlock_irq(&running_trace_lock); 1613 relay_flush(bt->rchan); 1614 } 1615 1616 put_probe_ref(); 1617 synchronize_rcu(); 1618 blk_trace_free(bt); 1619 return 0; 1620 } 1621 1622 /* 1623 * Setup everything required to start tracing 1624 */ 1625 static int blk_trace_setup_queue(struct request_queue *q, 1626 struct block_device *bdev) 1627 { 1628 struct blk_trace *bt = NULL; 1629 int ret = -ENOMEM; 1630 1631 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1632 if (!bt) 1633 return -ENOMEM; 1634 1635 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1636 if (!bt->msg_data) 1637 goto free_bt; 1638 1639 bt->dev = bdev->bd_dev; 1640 bt->act_mask = (u16)-1; 1641 1642 blk_trace_setup_lba(bt, bdev); 1643 1644 rcu_assign_pointer(q->blk_trace, bt); 1645 get_probe_ref(); 1646 return 0; 1647 1648 free_bt: 1649 blk_trace_free(bt); 1650 return ret; 1651 } 1652 1653 /* 1654 * sysfs interface to enable and configure tracing 1655 */ 1656 1657 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1658 struct device_attribute *attr, 1659 char *buf); 1660 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1661 struct device_attribute *attr, 1662 const char *buf, size_t count); 1663 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1664 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1665 sysfs_blk_trace_attr_show, \ 1666 sysfs_blk_trace_attr_store) 1667 1668 static BLK_TRACE_DEVICE_ATTR(enable); 1669 static BLK_TRACE_DEVICE_ATTR(act_mask); 1670 static BLK_TRACE_DEVICE_ATTR(pid); 1671 static BLK_TRACE_DEVICE_ATTR(start_lba); 1672 static BLK_TRACE_DEVICE_ATTR(end_lba); 1673 1674 static struct attribute *blk_trace_attrs[] = { 1675 &dev_attr_enable.attr, 1676 &dev_attr_act_mask.attr, 1677 &dev_attr_pid.attr, 1678 &dev_attr_start_lba.attr, 1679 &dev_attr_end_lba.attr, 1680 NULL 1681 }; 1682 1683 struct attribute_group blk_trace_attr_group = { 1684 .name = "trace", 1685 .attrs = blk_trace_attrs, 1686 }; 1687 1688 static const struct { 1689 int mask; 1690 const char *str; 1691 } mask_maps[] = { 1692 { BLK_TC_READ, "read" }, 1693 { BLK_TC_WRITE, "write" }, 1694 { BLK_TC_FLUSH, "flush" }, 1695 { BLK_TC_SYNC, "sync" }, 1696 { BLK_TC_QUEUE, "queue" }, 1697 { BLK_TC_REQUEUE, "requeue" }, 1698 { BLK_TC_ISSUE, "issue" }, 1699 { BLK_TC_COMPLETE, "complete" }, 1700 { BLK_TC_FS, "fs" }, 1701 { BLK_TC_PC, "pc" }, 1702 { BLK_TC_NOTIFY, "notify" }, 1703 { BLK_TC_AHEAD, "ahead" }, 1704 { BLK_TC_META, "meta" }, 1705 { BLK_TC_DISCARD, "discard" }, 1706 { BLK_TC_DRV_DATA, "drv_data" }, 1707 { BLK_TC_FUA, "fua" }, 1708 }; 1709 1710 static int blk_trace_str2mask(const char *str) 1711 { 1712 int i; 1713 int mask = 0; 1714 char *buf, *s, *token; 1715 1716 buf = kstrdup(str, GFP_KERNEL); 1717 if (buf == NULL) 1718 return -ENOMEM; 1719 s = strstrip(buf); 1720 1721 while (1) { 1722 token = strsep(&s, ","); 1723 if (token == NULL) 1724 break; 1725 1726 if (*token == '\0') 1727 continue; 1728 1729 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1730 if (strcasecmp(token, mask_maps[i].str) == 0) { 1731 mask |= mask_maps[i].mask; 1732 break; 1733 } 1734 } 1735 if (i == ARRAY_SIZE(mask_maps)) { 1736 mask = -EINVAL; 1737 break; 1738 } 1739 } 1740 kfree(buf); 1741 1742 return mask; 1743 } 1744 1745 static ssize_t blk_trace_mask2str(char *buf, int mask) 1746 { 1747 int i; 1748 char *p = buf; 1749 1750 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1751 if (mask & mask_maps[i].mask) { 1752 p += sprintf(p, "%s%s", 1753 (p == buf) ? "" : ",", mask_maps[i].str); 1754 } 1755 } 1756 *p++ = '\n'; 1757 1758 return p - buf; 1759 } 1760 1761 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1762 struct device_attribute *attr, 1763 char *buf) 1764 { 1765 struct block_device *bdev = dev_to_bdev(dev); 1766 struct request_queue *q = bdev_get_queue(bdev); 1767 struct blk_trace *bt; 1768 ssize_t ret = -ENXIO; 1769 1770 mutex_lock(&q->debugfs_mutex); 1771 1772 bt = rcu_dereference_protected(q->blk_trace, 1773 lockdep_is_held(&q->debugfs_mutex)); 1774 if (attr == &dev_attr_enable) { 1775 ret = sprintf(buf, "%u\n", !!bt); 1776 goto out_unlock_bdev; 1777 } 1778 1779 if (bt == NULL) 1780 ret = sprintf(buf, "disabled\n"); 1781 else if (attr == &dev_attr_act_mask) 1782 ret = blk_trace_mask2str(buf, bt->act_mask); 1783 else if (attr == &dev_attr_pid) 1784 ret = sprintf(buf, "%u\n", bt->pid); 1785 else if (attr == &dev_attr_start_lba) 1786 ret = sprintf(buf, "%llu\n", bt->start_lba); 1787 else if (attr == &dev_attr_end_lba) 1788 ret = sprintf(buf, "%llu\n", bt->end_lba); 1789 1790 out_unlock_bdev: 1791 mutex_unlock(&q->debugfs_mutex); 1792 return ret; 1793 } 1794 1795 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1796 struct device_attribute *attr, 1797 const char *buf, size_t count) 1798 { 1799 struct block_device *bdev = dev_to_bdev(dev); 1800 struct request_queue *q = bdev_get_queue(bdev); 1801 struct blk_trace *bt; 1802 u64 value; 1803 ssize_t ret = -EINVAL; 1804 1805 if (count == 0) 1806 goto out; 1807 1808 if (attr == &dev_attr_act_mask) { 1809 if (kstrtoull(buf, 0, &value)) { 1810 /* Assume it is a list of trace category names */ 1811 ret = blk_trace_str2mask(buf); 1812 if (ret < 0) 1813 goto out; 1814 value = ret; 1815 } 1816 } else { 1817 if (kstrtoull(buf, 0, &value)) 1818 goto out; 1819 } 1820 1821 mutex_lock(&q->debugfs_mutex); 1822 1823 bt = rcu_dereference_protected(q->blk_trace, 1824 lockdep_is_held(&q->debugfs_mutex)); 1825 if (attr == &dev_attr_enable) { 1826 if (!!value == !!bt) { 1827 ret = 0; 1828 goto out_unlock_bdev; 1829 } 1830 if (value) 1831 ret = blk_trace_setup_queue(q, bdev); 1832 else 1833 ret = blk_trace_remove_queue(q); 1834 goto out_unlock_bdev; 1835 } 1836 1837 ret = 0; 1838 if (bt == NULL) { 1839 ret = blk_trace_setup_queue(q, bdev); 1840 bt = rcu_dereference_protected(q->blk_trace, 1841 lockdep_is_held(&q->debugfs_mutex)); 1842 } 1843 1844 if (ret == 0) { 1845 if (attr == &dev_attr_act_mask) 1846 bt->act_mask = value; 1847 else if (attr == &dev_attr_pid) 1848 bt->pid = value; 1849 else if (attr == &dev_attr_start_lba) 1850 bt->start_lba = value; 1851 else if (attr == &dev_attr_end_lba) 1852 bt->end_lba = value; 1853 } 1854 1855 out_unlock_bdev: 1856 mutex_unlock(&q->debugfs_mutex); 1857 out: 1858 return ret ? ret : count; 1859 } 1860 1861 int blk_trace_init_sysfs(struct device *dev) 1862 { 1863 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1864 } 1865 1866 void blk_trace_remove_sysfs(struct device *dev) 1867 { 1868 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1869 } 1870 1871 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1872 1873 #ifdef CONFIG_EVENT_TRACING 1874 1875 /** 1876 * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string. 1877 * @rwbs: buffer to be filled 1878 * @op: REQ_OP_XXX for the tracepoint 1879 * 1880 * Description: 1881 * Maps the REQ_OP_XXX to character and fills the buffer provided by the 1882 * caller with resulting string. 1883 * 1884 **/ 1885 void blk_fill_rwbs(char *rwbs, unsigned int op) 1886 { 1887 int i = 0; 1888 1889 if (op & REQ_PREFLUSH) 1890 rwbs[i++] = 'F'; 1891 1892 switch (op & REQ_OP_MASK) { 1893 case REQ_OP_WRITE: 1894 case REQ_OP_WRITE_SAME: 1895 rwbs[i++] = 'W'; 1896 break; 1897 case REQ_OP_DISCARD: 1898 rwbs[i++] = 'D'; 1899 break; 1900 case REQ_OP_SECURE_ERASE: 1901 rwbs[i++] = 'D'; 1902 rwbs[i++] = 'E'; 1903 break; 1904 case REQ_OP_FLUSH: 1905 rwbs[i++] = 'F'; 1906 break; 1907 case REQ_OP_READ: 1908 rwbs[i++] = 'R'; 1909 break; 1910 default: 1911 rwbs[i++] = 'N'; 1912 } 1913 1914 if (op & REQ_FUA) 1915 rwbs[i++] = 'F'; 1916 if (op & REQ_RAHEAD) 1917 rwbs[i++] = 'A'; 1918 if (op & REQ_SYNC) 1919 rwbs[i++] = 'S'; 1920 if (op & REQ_META) 1921 rwbs[i++] = 'M'; 1922 1923 rwbs[i] = '\0'; 1924 } 1925 EXPORT_SYMBOL_GPL(blk_fill_rwbs); 1926 1927 #endif /* CONFIG_EVENT_TRACING */ 1928 1929