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 31static unsigned int blktrace_seq __read_mostly = 1; 32 33static struct trace_array *blk_tr; 34static bool blk_tracer_enabled __read_mostly; 35 36static LIST_HEAD(running_trace_list); 37static __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 44static 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 54static struct tracer_flags blk_tracer_flags = { 55 .val = 0, 56 .opts = blk_tracer_opts, 57}; 58 59/* Global reference count of probes */ 60static DEFINE_MUTEX(blk_probe_mutex); 61static int blk_probes_ref; 62 63static void blk_register_tracepoints(void); 64static void blk_unregister_tracepoints(void); 65 66/* 67 * Send out a notify message. 68 */ 69static 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()); 99record_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 */ 118static 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 132static 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 148void __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} 183EXPORT_SYMBOL_GPL(__blk_trace_note_message); 184 185static 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 */ 201static 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 */ 215static 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()); 283record_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 314static 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_lookup_and_remove("dropped", q->debugfs_dir); 324 debugfs_lookup_and_remove("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 333static 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 341static 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 349static 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 366static 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 380static 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 388static 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 402int 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} 412EXPORT_SYMBOL_GPL(blk_trace_remove); 413 414static 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 425static 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 432static 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 452static 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 */ 463static 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 476static int blk_remove_buf_file_callback(struct dentry *dentry) 477{ 478 debugfs_remove(dentry); 479 480 return 0; 481} 482 483static 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 493static 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 499static 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 */ 514static 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 strscpy_pad(buts->name, name, BLKTRACE_BDEV_SIZE); 528 529 /* 530 * some device names have larger paths - convert the slashes 531 * to underscores for this to work as expected 532 */ 533 strreplace(buts->name, '/', '_'); 534 535 /* 536 * bdev can be NULL, as with scsi-generic, this is a helpful as 537 * we can be. 538 */ 539 if (rcu_dereference_protected(q->blk_trace, 540 lockdep_is_held(&q->debugfs_mutex))) { 541 pr_warn("Concurrent blktraces are not allowed on %s\n", 542 buts->name); 543 return -EBUSY; 544 } 545 546 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 547 if (!bt) 548 return -ENOMEM; 549 550 ret = -ENOMEM; 551 bt->sequence = alloc_percpu(unsigned long); 552 if (!bt->sequence) 553 goto err; 554 555 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 556 if (!bt->msg_data) 557 goto err; 558 559 /* 560 * When tracing the whole disk reuse the existing debugfs directory 561 * created by the block layer on init. For partitions block devices, 562 * and scsi-generic block devices we create a temporary new debugfs 563 * directory that will be removed once the trace ends. 564 */ 565 if (bdev && !bdev_is_partition(bdev)) 566 dir = q->debugfs_dir; 567 else 568 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root); 569 570 /* 571 * As blktrace relies on debugfs for its interface the debugfs directory 572 * is required, contrary to the usual mantra of not checking for debugfs 573 * files or directories. 574 */ 575 if (IS_ERR_OR_NULL(dir)) { 576 pr_warn("debugfs_dir not present for %s so skipping\n", 577 buts->name); 578 ret = -ENOENT; 579 goto err; 580 } 581 582 bt->dev = dev; 583 atomic_set(&bt->dropped, 0); 584 INIT_LIST_HEAD(&bt->running_list); 585 586 ret = -EIO; 587 debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops); 588 debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 589 590 bt->rchan = relay_open("trace", dir, buts->buf_size, 591 buts->buf_nr, &blk_relay_callbacks, bt); 592 if (!bt->rchan) 593 goto err; 594 595 bt->act_mask = buts->act_mask; 596 if (!bt->act_mask) 597 bt->act_mask = (u16) -1; 598 599 blk_trace_setup_lba(bt, bdev); 600 601 /* overwrite with user settings */ 602 if (buts->start_lba) 603 bt->start_lba = buts->start_lba; 604 if (buts->end_lba) 605 bt->end_lba = buts->end_lba; 606 607 bt->pid = buts->pid; 608 bt->trace_state = Blktrace_setup; 609 610 rcu_assign_pointer(q->blk_trace, bt); 611 get_probe_ref(); 612 613 ret = 0; 614err: 615 if (ret) 616 blk_trace_free(q, bt); 617 return ret; 618} 619 620static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 621 struct block_device *bdev, char __user *arg) 622{ 623 struct blk_user_trace_setup buts; 624 int ret; 625 626 ret = copy_from_user(&buts, arg, sizeof(buts)); 627 if (ret) 628 return -EFAULT; 629 630 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 631 if (ret) 632 return ret; 633 634 if (copy_to_user(arg, &buts, sizeof(buts))) { 635 __blk_trace_remove(q); 636 return -EFAULT; 637 } 638 return 0; 639} 640 641int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 642 struct block_device *bdev, 643 char __user *arg) 644{ 645 int ret; 646 647 mutex_lock(&q->debugfs_mutex); 648 ret = __blk_trace_setup(q, name, dev, bdev, arg); 649 mutex_unlock(&q->debugfs_mutex); 650 651 return ret; 652} 653EXPORT_SYMBOL_GPL(blk_trace_setup); 654 655#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 656static int compat_blk_trace_setup(struct request_queue *q, char *name, 657 dev_t dev, struct block_device *bdev, 658 char __user *arg) 659{ 660 struct blk_user_trace_setup buts; 661 struct compat_blk_user_trace_setup cbuts; 662 int ret; 663 664 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 665 return -EFAULT; 666 667 buts = (struct blk_user_trace_setup) { 668 .act_mask = cbuts.act_mask, 669 .buf_size = cbuts.buf_size, 670 .buf_nr = cbuts.buf_nr, 671 .start_lba = cbuts.start_lba, 672 .end_lba = cbuts.end_lba, 673 .pid = cbuts.pid, 674 }; 675 676 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 677 if (ret) 678 return ret; 679 680 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) { 681 __blk_trace_remove(q); 682 return -EFAULT; 683 } 684 685 return 0; 686} 687#endif 688 689static int __blk_trace_startstop(struct request_queue *q, int start) 690{ 691 struct blk_trace *bt; 692 693 bt = rcu_dereference_protected(q->blk_trace, 694 lockdep_is_held(&q->debugfs_mutex)); 695 if (bt == NULL) 696 return -EINVAL; 697 698 if (start) 699 return blk_trace_start(bt); 700 else 701 return blk_trace_stop(bt); 702} 703 704int blk_trace_startstop(struct request_queue *q, int start) 705{ 706 int ret; 707 708 mutex_lock(&q->debugfs_mutex); 709 ret = __blk_trace_startstop(q, start); 710 mutex_unlock(&q->debugfs_mutex); 711 712 return ret; 713} 714EXPORT_SYMBOL_GPL(blk_trace_startstop); 715 716/* 717 * When reading or writing the blktrace sysfs files, the references to the 718 * opened sysfs or device files should prevent the underlying block device 719 * from being removed. So no further delete protection is really needed. 720 */ 721 722/** 723 * blk_trace_ioctl - handle the ioctls associated with tracing 724 * @bdev: the block device 725 * @cmd: the ioctl cmd 726 * @arg: the argument data, if any 727 * 728 **/ 729int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 730{ 731 struct request_queue *q = bdev_get_queue(bdev); 732 int ret, start = 0; 733 char b[BDEVNAME_SIZE]; 734 735 mutex_lock(&q->debugfs_mutex); 736 737 switch (cmd) { 738 case BLKTRACESETUP: 739 snprintf(b, sizeof(b), "%pg", bdev); 740 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 741 break; 742#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 743 case BLKTRACESETUP32: 744 snprintf(b, sizeof(b), "%pg", bdev); 745 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 746 break; 747#endif 748 case BLKTRACESTART: 749 start = 1; 750 fallthrough; 751 case BLKTRACESTOP: 752 ret = __blk_trace_startstop(q, start); 753 break; 754 case BLKTRACETEARDOWN: 755 ret = __blk_trace_remove(q); 756 break; 757 default: 758 ret = -ENOTTY; 759 break; 760 } 761 762 mutex_unlock(&q->debugfs_mutex); 763 return ret; 764} 765 766/** 767 * blk_trace_shutdown - stop and cleanup trace structures 768 * @q: the request queue associated with the device 769 * 770 **/ 771void blk_trace_shutdown(struct request_queue *q) 772{ 773 if (rcu_dereference_protected(q->blk_trace, 774 lockdep_is_held(&q->debugfs_mutex))) 775 __blk_trace_remove(q); 776} 777 778#ifdef CONFIG_BLK_CGROUP 779static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) 780{ 781 struct cgroup_subsys_state *blkcg_css; 782 struct blk_trace *bt; 783 784 /* We don't use the 'bt' value here except as an optimization... */ 785 bt = rcu_dereference_protected(q->blk_trace, 1); 786 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP)) 787 return 0; 788 789 blkcg_css = bio_blkcg_css(bio); 790 if (!blkcg_css) 791 return 0; 792 return cgroup_id(blkcg_css->cgroup); 793} 794#else 795static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) 796{ 797 return 0; 798} 799#endif 800 801static u64 802blk_trace_request_get_cgid(struct request *rq) 803{ 804 if (!rq->bio) 805 return 0; 806 /* Use the first bio */ 807 return blk_trace_bio_get_cgid(rq->q, rq->bio); 808} 809 810/* 811 * blktrace probes 812 */ 813 814/** 815 * blk_add_trace_rq - Add a trace for a request oriented action 816 * @rq: the source request 817 * @error: return status to log 818 * @nr_bytes: number of completed bytes 819 * @what: the action 820 * @cgid: the cgroup info 821 * 822 * Description: 823 * Records an action against a request. Will log the bio offset + size. 824 * 825 **/ 826static void blk_add_trace_rq(struct request *rq, blk_status_t error, 827 unsigned int nr_bytes, u32 what, u64 cgid) 828{ 829 struct blk_trace *bt; 830 831 rcu_read_lock(); 832 bt = rcu_dereference(rq->q->blk_trace); 833 if (likely(!bt)) { 834 rcu_read_unlock(); 835 return; 836 } 837 838 if (blk_rq_is_passthrough(rq)) 839 what |= BLK_TC_ACT(BLK_TC_PC); 840 else 841 what |= BLK_TC_ACT(BLK_TC_FS); 842 843 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, rq->cmd_flags, 844 what, blk_status_to_errno(error), 0, NULL, cgid); 845 rcu_read_unlock(); 846} 847 848static void blk_add_trace_rq_insert(void *ignore, struct request *rq) 849{ 850 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT, 851 blk_trace_request_get_cgid(rq)); 852} 853 854static void blk_add_trace_rq_issue(void *ignore, struct request *rq) 855{ 856 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE, 857 blk_trace_request_get_cgid(rq)); 858} 859 860static void blk_add_trace_rq_merge(void *ignore, struct request *rq) 861{ 862 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE, 863 blk_trace_request_get_cgid(rq)); 864} 865 866static void blk_add_trace_rq_requeue(void *ignore, struct request *rq) 867{ 868 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE, 869 blk_trace_request_get_cgid(rq)); 870} 871 872static void blk_add_trace_rq_complete(void *ignore, struct request *rq, 873 blk_status_t error, unsigned int nr_bytes) 874{ 875 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE, 876 blk_trace_request_get_cgid(rq)); 877} 878 879/** 880 * blk_add_trace_bio - Add a trace for a bio oriented action 881 * @q: queue the io is for 882 * @bio: the source bio 883 * @what: the action 884 * @error: error, if any 885 * 886 * Description: 887 * Records an action against a bio. Will log the bio offset + size. 888 * 889 **/ 890static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 891 u32 what, int error) 892{ 893 struct blk_trace *bt; 894 895 rcu_read_lock(); 896 bt = rcu_dereference(q->blk_trace); 897 if (likely(!bt)) { 898 rcu_read_unlock(); 899 return; 900 } 901 902 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 903 bio->bi_opf, what, error, 0, NULL, 904 blk_trace_bio_get_cgid(q, bio)); 905 rcu_read_unlock(); 906} 907 908static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio) 909{ 910 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0); 911} 912 913static void blk_add_trace_bio_complete(void *ignore, 914 struct request_queue *q, struct bio *bio) 915{ 916 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, 917 blk_status_to_errno(bio->bi_status)); 918} 919 920static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio) 921{ 922 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE, 923 0); 924} 925 926static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio) 927{ 928 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE, 929 0); 930} 931 932static void blk_add_trace_bio_queue(void *ignore, struct bio *bio) 933{ 934 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0); 935} 936 937static void blk_add_trace_getrq(void *ignore, struct bio *bio) 938{ 939 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0); 940} 941 942static void blk_add_trace_plug(void *ignore, struct request_queue *q) 943{ 944 struct blk_trace *bt; 945 946 rcu_read_lock(); 947 bt = rcu_dereference(q->blk_trace); 948 if (bt) 949 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0); 950 rcu_read_unlock(); 951} 952 953static void blk_add_trace_unplug(void *ignore, struct request_queue *q, 954 unsigned int depth, bool explicit) 955{ 956 struct blk_trace *bt; 957 958 rcu_read_lock(); 959 bt = rcu_dereference(q->blk_trace); 960 if (bt) { 961 __be64 rpdu = cpu_to_be64(depth); 962 u32 what; 963 964 if (explicit) 965 what = BLK_TA_UNPLUG_IO; 966 else 967 what = BLK_TA_UNPLUG_TIMER; 968 969 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0); 970 } 971 rcu_read_unlock(); 972} 973 974static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu) 975{ 976 struct request_queue *q = bio->bi_bdev->bd_disk->queue; 977 struct blk_trace *bt; 978 979 rcu_read_lock(); 980 bt = rcu_dereference(q->blk_trace); 981 if (bt) { 982 __be64 rpdu = cpu_to_be64(pdu); 983 984 __blk_add_trace(bt, bio->bi_iter.bi_sector, 985 bio->bi_iter.bi_size, bio->bi_opf, BLK_TA_SPLIT, 986 blk_status_to_errno(bio->bi_status), 987 sizeof(rpdu), &rpdu, 988 blk_trace_bio_get_cgid(q, bio)); 989 } 990 rcu_read_unlock(); 991} 992 993/** 994 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation 995 * @ignore: trace callback data parameter (not used) 996 * @bio: the source bio 997 * @dev: source device 998 * @from: source sector 999 * 1000 * Called after a bio is remapped to a different device and/or sector. 1001 **/ 1002static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev, 1003 sector_t from) 1004{ 1005 struct request_queue *q = bio->bi_bdev->bd_disk->queue; 1006 struct blk_trace *bt; 1007 struct blk_io_trace_remap r; 1008 1009 rcu_read_lock(); 1010 bt = rcu_dereference(q->blk_trace); 1011 if (likely(!bt)) { 1012 rcu_read_unlock(); 1013 return; 1014 } 1015 1016 r.device_from = cpu_to_be32(dev); 1017 r.device_to = cpu_to_be32(bio_dev(bio)); 1018 r.sector_from = cpu_to_be64(from); 1019 1020 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 1021 bio->bi_opf, BLK_TA_REMAP, 1022 blk_status_to_errno(bio->bi_status), 1023 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio)); 1024 rcu_read_unlock(); 1025} 1026 1027/** 1028 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 1029 * @ignore: trace callback data parameter (not used) 1030 * @rq: the source request 1031 * @dev: target device 1032 * @from: source sector 1033 * 1034 * Description: 1035 * Device mapper remaps request to other devices. 1036 * Add a trace for that action. 1037 * 1038 **/ 1039static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev, 1040 sector_t from) 1041{ 1042 struct blk_trace *bt; 1043 struct blk_io_trace_remap r; 1044 1045 rcu_read_lock(); 1046 bt = rcu_dereference(rq->q->blk_trace); 1047 if (likely(!bt)) { 1048 rcu_read_unlock(); 1049 return; 1050 } 1051 1052 r.device_from = cpu_to_be32(dev); 1053 r.device_to = cpu_to_be32(disk_devt(rq->q->disk)); 1054 r.sector_from = cpu_to_be64(from); 1055 1056 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 1057 rq->cmd_flags, BLK_TA_REMAP, 0, 1058 sizeof(r), &r, blk_trace_request_get_cgid(rq)); 1059 rcu_read_unlock(); 1060} 1061 1062/** 1063 * blk_add_driver_data - Add binary message with driver-specific data 1064 * @rq: io request 1065 * @data: driver-specific data 1066 * @len: length of driver-specific data 1067 * 1068 * Description: 1069 * Some drivers might want to write driver-specific data per request. 1070 * 1071 **/ 1072void blk_add_driver_data(struct request *rq, void *data, size_t len) 1073{ 1074 struct blk_trace *bt; 1075 1076 rcu_read_lock(); 1077 bt = rcu_dereference(rq->q->blk_trace); 1078 if (likely(!bt)) { 1079 rcu_read_unlock(); 1080 return; 1081 } 1082 1083 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 1084 BLK_TA_DRV_DATA, 0, len, data, 1085 blk_trace_request_get_cgid(rq)); 1086 rcu_read_unlock(); 1087} 1088EXPORT_SYMBOL_GPL(blk_add_driver_data); 1089 1090static void blk_register_tracepoints(void) 1091{ 1092 int ret; 1093 1094 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1095 WARN_ON(ret); 1096 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1097 WARN_ON(ret); 1098 ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL); 1099 WARN_ON(ret); 1100 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1101 WARN_ON(ret); 1102 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1103 WARN_ON(ret); 1104 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1105 WARN_ON(ret); 1106 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1107 WARN_ON(ret); 1108 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1109 WARN_ON(ret); 1110 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1111 WARN_ON(ret); 1112 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1113 WARN_ON(ret); 1114 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 1115 WARN_ON(ret); 1116 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 1117 WARN_ON(ret); 1118 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL); 1119 WARN_ON(ret); 1120 ret = register_trace_block_split(blk_add_trace_split, NULL); 1121 WARN_ON(ret); 1122 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1123 WARN_ON(ret); 1124 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1125 WARN_ON(ret); 1126} 1127 1128static void blk_unregister_tracepoints(void) 1129{ 1130 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1131 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1132 unregister_trace_block_split(blk_add_trace_split, NULL); 1133 unregister_trace_block_unplug(blk_add_trace_unplug, NULL); 1134 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1135 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1136 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1137 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1138 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1139 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1140 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1141 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1142 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1143 unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL); 1144 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1145 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1146 1147 tracepoint_synchronize_unregister(); 1148} 1149 1150/* 1151 * struct blk_io_tracer formatting routines 1152 */ 1153 1154static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1155{ 1156 int i = 0; 1157 int tc = t->action >> BLK_TC_SHIFT; 1158 1159 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { 1160 rwbs[i++] = 'N'; 1161 goto out; 1162 } 1163 1164 if (tc & BLK_TC_FLUSH) 1165 rwbs[i++] = 'F'; 1166 1167 if (tc & BLK_TC_DISCARD) 1168 rwbs[i++] = 'D'; 1169 else if (tc & BLK_TC_WRITE) 1170 rwbs[i++] = 'W'; 1171 else if (t->bytes) 1172 rwbs[i++] = 'R'; 1173 else 1174 rwbs[i++] = 'N'; 1175 1176 if (tc & BLK_TC_FUA) 1177 rwbs[i++] = 'F'; 1178 if (tc & BLK_TC_AHEAD) 1179 rwbs[i++] = 'A'; 1180 if (tc & BLK_TC_SYNC) 1181 rwbs[i++] = 'S'; 1182 if (tc & BLK_TC_META) 1183 rwbs[i++] = 'M'; 1184out: 1185 rwbs[i] = '\0'; 1186} 1187 1188static inline 1189const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1190{ 1191 return (const struct blk_io_trace *)ent; 1192} 1193 1194static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg) 1195{ 1196 return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0); 1197} 1198 1199static inline u64 t_cgid(const struct trace_entry *ent) 1200{ 1201 return *(u64 *)(te_blk_io_trace(ent) + 1); 1202} 1203 1204static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg) 1205{ 1206 return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0); 1207} 1208 1209static inline u32 t_action(const struct trace_entry *ent) 1210{ 1211 return te_blk_io_trace(ent)->action; 1212} 1213 1214static inline u32 t_bytes(const struct trace_entry *ent) 1215{ 1216 return te_blk_io_trace(ent)->bytes; 1217} 1218 1219static inline u32 t_sec(const struct trace_entry *ent) 1220{ 1221 return te_blk_io_trace(ent)->bytes >> 9; 1222} 1223 1224static inline unsigned long long t_sector(const struct trace_entry *ent) 1225{ 1226 return te_blk_io_trace(ent)->sector; 1227} 1228 1229static inline __u16 t_error(const struct trace_entry *ent) 1230{ 1231 return te_blk_io_trace(ent)->error; 1232} 1233 1234static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg) 1235{ 1236 const __be64 *val = pdu_start(ent, has_cg); 1237 return be64_to_cpu(*val); 1238} 1239 1240typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act, 1241 bool has_cg); 1242 1243static void blk_log_action_classic(struct trace_iterator *iter, const char *act, 1244 bool has_cg) 1245{ 1246 char rwbs[RWBS_LEN]; 1247 unsigned long long ts = iter->ts; 1248 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1249 unsigned secs = (unsigned long)ts; 1250 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1251 1252 fill_rwbs(rwbs, t); 1253 1254 trace_seq_printf(&iter->seq, 1255 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1256 MAJOR(t->device), MINOR(t->device), iter->cpu, 1257 secs, nsec_rem, iter->ent->pid, act, rwbs); 1258} 1259 1260static void blk_log_action(struct trace_iterator *iter, const char *act, 1261 bool has_cg) 1262{ 1263 char rwbs[RWBS_LEN]; 1264 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1265 1266 fill_rwbs(rwbs, t); 1267 if (has_cg) { 1268 u64 id = t_cgid(iter->ent); 1269 1270 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) { 1271 char blkcg_name_buf[NAME_MAX + 1] = "<...>"; 1272 1273 cgroup_path_from_kernfs_id(id, blkcg_name_buf, 1274 sizeof(blkcg_name_buf)); 1275 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ", 1276 MAJOR(t->device), MINOR(t->device), 1277 blkcg_name_buf, act, rwbs); 1278 } else { 1279 /* 1280 * The cgid portion used to be "INO,GEN". Userland 1281 * builds a FILEID_INO32_GEN fid out of them and 1282 * opens the cgroup using open_by_handle_at(2). 1283 * While 32bit ino setups are still the same, 64bit 1284 * ones now use the 64bit ino as the whole ID and 1285 * no longer use generation. 1286 * 1287 * Regardless of the content, always output 1288 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can 1289 * be mapped back to @id on both 64 and 32bit ino 1290 * setups. See __kernfs_fh_to_dentry(). 1291 */ 1292 trace_seq_printf(&iter->seq, 1293 "%3d,%-3d %llx,%-llx %2s %3s ", 1294 MAJOR(t->device), MINOR(t->device), 1295 id & U32_MAX, id >> 32, act, rwbs); 1296 } 1297 } else 1298 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1299 MAJOR(t->device), MINOR(t->device), act, rwbs); 1300} 1301 1302static void blk_log_dump_pdu(struct trace_seq *s, 1303 const struct trace_entry *ent, bool has_cg) 1304{ 1305 const unsigned char *pdu_buf; 1306 int pdu_len; 1307 int i, end; 1308 1309 pdu_buf = pdu_start(ent, has_cg); 1310 pdu_len = pdu_real_len(ent, has_cg); 1311 1312 if (!pdu_len) 1313 return; 1314 1315 /* find the last zero that needs to be printed */ 1316 for (end = pdu_len - 1; end >= 0; end--) 1317 if (pdu_buf[end]) 1318 break; 1319 end++; 1320 1321 trace_seq_putc(s, '('); 1322 1323 for (i = 0; i < pdu_len; i++) { 1324 1325 trace_seq_printf(s, "%s%02x", 1326 i == 0 ? "" : " ", pdu_buf[i]); 1327 1328 /* 1329 * stop when the rest is just zeros and indicate so 1330 * with a ".." appended 1331 */ 1332 if (i == end && end != pdu_len - 1) { 1333 trace_seq_puts(s, " ..) "); 1334 return; 1335 } 1336 } 1337 1338 trace_seq_puts(s, ") "); 1339} 1340 1341static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1342{ 1343 char cmd[TASK_COMM_LEN]; 1344 1345 trace_find_cmdline(ent->pid, cmd); 1346 1347 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1348 trace_seq_printf(s, "%u ", t_bytes(ent)); 1349 blk_log_dump_pdu(s, ent, has_cg); 1350 trace_seq_printf(s, "[%s]\n", cmd); 1351 } else { 1352 if (t_sec(ent)) 1353 trace_seq_printf(s, "%llu + %u [%s]\n", 1354 t_sector(ent), t_sec(ent), cmd); 1355 else 1356 trace_seq_printf(s, "[%s]\n", cmd); 1357 } 1358} 1359 1360static void blk_log_with_error(struct trace_seq *s, 1361 const struct trace_entry *ent, bool has_cg) 1362{ 1363 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1364 blk_log_dump_pdu(s, ent, has_cg); 1365 trace_seq_printf(s, "[%d]\n", t_error(ent)); 1366 } else { 1367 if (t_sec(ent)) 1368 trace_seq_printf(s, "%llu + %u [%d]\n", 1369 t_sector(ent), 1370 t_sec(ent), t_error(ent)); 1371 else 1372 trace_seq_printf(s, "%llu [%d]\n", 1373 t_sector(ent), t_error(ent)); 1374 } 1375} 1376 1377static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1378{ 1379 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg); 1380 1381 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1382 t_sector(ent), t_sec(ent), 1383 MAJOR(be32_to_cpu(__r->device_from)), 1384 MINOR(be32_to_cpu(__r->device_from)), 1385 be64_to_cpu(__r->sector_from)); 1386} 1387 1388static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1389{ 1390 char cmd[TASK_COMM_LEN]; 1391 1392 trace_find_cmdline(ent->pid, cmd); 1393 1394 trace_seq_printf(s, "[%s]\n", cmd); 1395} 1396 1397static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1398{ 1399 char cmd[TASK_COMM_LEN]; 1400 1401 trace_find_cmdline(ent->pid, cmd); 1402 1403 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg)); 1404} 1405 1406static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1407{ 1408 char cmd[TASK_COMM_LEN]; 1409 1410 trace_find_cmdline(ent->pid, cmd); 1411 1412 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1413 get_pdu_int(ent, has_cg), cmd); 1414} 1415 1416static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent, 1417 bool has_cg) 1418{ 1419 1420 trace_seq_putmem(s, pdu_start(ent, has_cg), 1421 pdu_real_len(ent, has_cg)); 1422 trace_seq_putc(s, '\n'); 1423} 1424 1425/* 1426 * struct tracer operations 1427 */ 1428 1429static void blk_tracer_print_header(struct seq_file *m) 1430{ 1431 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1432 return; 1433 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1434 "# | | | | | |\n"); 1435} 1436 1437static void blk_tracer_start(struct trace_array *tr) 1438{ 1439 blk_tracer_enabled = true; 1440} 1441 1442static int blk_tracer_init(struct trace_array *tr) 1443{ 1444 blk_tr = tr; 1445 blk_tracer_start(tr); 1446 return 0; 1447} 1448 1449static void blk_tracer_stop(struct trace_array *tr) 1450{ 1451 blk_tracer_enabled = false; 1452} 1453 1454static void blk_tracer_reset(struct trace_array *tr) 1455{ 1456 blk_tracer_stop(tr); 1457} 1458 1459static const struct { 1460 const char *act[2]; 1461 void (*print)(struct trace_seq *s, const struct trace_entry *ent, 1462 bool has_cg); 1463} what2act[] = { 1464 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1465 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1466 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1467 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1468 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1469 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1470 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1471 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1472 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1473 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1474 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1475 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1476 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1477 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1478 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1479}; 1480 1481static enum print_line_t print_one_line(struct trace_iterator *iter, 1482 bool classic) 1483{ 1484 struct trace_array *tr = iter->tr; 1485 struct trace_seq *s = &iter->seq; 1486 const struct blk_io_trace *t; 1487 u16 what; 1488 bool long_act; 1489 blk_log_action_t *log_action; 1490 bool has_cg; 1491 1492 t = te_blk_io_trace(iter->ent); 1493 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP; 1494 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE); 1495 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1496 has_cg = t->action & __BLK_TA_CGROUP; 1497 1498 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { 1499 log_action(iter, long_act ? "message" : "m", has_cg); 1500 blk_log_msg(s, iter->ent, has_cg); 1501 return trace_handle_return(s); 1502 } 1503 1504 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1505 trace_seq_printf(s, "Unknown action %x\n", what); 1506 else { 1507 log_action(iter, what2act[what].act[long_act], has_cg); 1508 what2act[what].print(s, iter->ent, has_cg); 1509 } 1510 1511 return trace_handle_return(s); 1512} 1513 1514static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1515 int flags, struct trace_event *event) 1516{ 1517 return print_one_line(iter, false); 1518} 1519 1520static void blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1521{ 1522 struct trace_seq *s = &iter->seq; 1523 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1524 const int offset = offsetof(struct blk_io_trace, sector); 1525 struct blk_io_trace old = { 1526 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1527 .time = iter->ts, 1528 }; 1529 1530 trace_seq_putmem(s, &old, offset); 1531 trace_seq_putmem(s, &t->sector, 1532 sizeof(old) - offset + t->pdu_len); 1533} 1534 1535static enum print_line_t 1536blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1537 struct trace_event *event) 1538{ 1539 blk_trace_synthesize_old_trace(iter); 1540 1541 return trace_handle_return(&iter->seq); 1542} 1543 1544static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1545{ 1546 if ((iter->ent->type != TRACE_BLK) || 1547 !(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1548 return TRACE_TYPE_UNHANDLED; 1549 1550 return print_one_line(iter, true); 1551} 1552 1553static int 1554blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) 1555{ 1556 /* don't output context-info for blk_classic output */ 1557 if (bit == TRACE_BLK_OPT_CLASSIC) { 1558 if (set) 1559 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1560 else 1561 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO; 1562 } 1563 return 0; 1564} 1565 1566static struct tracer blk_tracer __read_mostly = { 1567 .name = "blk", 1568 .init = blk_tracer_init, 1569 .reset = blk_tracer_reset, 1570 .start = blk_tracer_start, 1571 .stop = blk_tracer_stop, 1572 .print_header = blk_tracer_print_header, 1573 .print_line = blk_tracer_print_line, 1574 .flags = &blk_tracer_flags, 1575 .set_flag = blk_tracer_set_flag, 1576}; 1577 1578static struct trace_event_functions trace_blk_event_funcs = { 1579 .trace = blk_trace_event_print, 1580 .binary = blk_trace_event_print_binary, 1581}; 1582 1583static struct trace_event trace_blk_event = { 1584 .type = TRACE_BLK, 1585 .funcs = &trace_blk_event_funcs, 1586}; 1587 1588static int __init init_blk_tracer(void) 1589{ 1590 if (!register_trace_event(&trace_blk_event)) { 1591 pr_warn("Warning: could not register block events\n"); 1592 return 1; 1593 } 1594 1595 if (register_tracer(&blk_tracer) != 0) { 1596 pr_warn("Warning: could not register the block tracer\n"); 1597 unregister_trace_event(&trace_blk_event); 1598 return 1; 1599 } 1600 1601 return 0; 1602} 1603 1604device_initcall(init_blk_tracer); 1605 1606static int blk_trace_remove_queue(struct request_queue *q) 1607{ 1608 struct blk_trace *bt; 1609 1610 bt = rcu_replace_pointer(q->blk_trace, NULL, 1611 lockdep_is_held(&q->debugfs_mutex)); 1612 if (bt == NULL) 1613 return -EINVAL; 1614 1615 blk_trace_stop(bt); 1616 1617 put_probe_ref(); 1618 synchronize_rcu(); 1619 blk_trace_free(q, bt); 1620 return 0; 1621} 1622 1623/* 1624 * Setup everything required to start tracing 1625 */ 1626static int blk_trace_setup_queue(struct request_queue *q, 1627 struct block_device *bdev) 1628{ 1629 struct blk_trace *bt = NULL; 1630 int ret = -ENOMEM; 1631 1632 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1633 if (!bt) 1634 return -ENOMEM; 1635 1636 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1637 if (!bt->msg_data) 1638 goto free_bt; 1639 1640 bt->dev = bdev->bd_dev; 1641 bt->act_mask = (u16)-1; 1642 1643 blk_trace_setup_lba(bt, bdev); 1644 1645 rcu_assign_pointer(q->blk_trace, bt); 1646 get_probe_ref(); 1647 return 0; 1648 1649free_bt: 1650 blk_trace_free(q, bt); 1651 return ret; 1652} 1653 1654/* 1655 * sysfs interface to enable and configure tracing 1656 */ 1657 1658static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1659 struct device_attribute *attr, 1660 char *buf); 1661static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1662 struct device_attribute *attr, 1663 const char *buf, size_t count); 1664#define BLK_TRACE_DEVICE_ATTR(_name) \ 1665 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1666 sysfs_blk_trace_attr_show, \ 1667 sysfs_blk_trace_attr_store) 1668 1669static BLK_TRACE_DEVICE_ATTR(enable); 1670static BLK_TRACE_DEVICE_ATTR(act_mask); 1671static BLK_TRACE_DEVICE_ATTR(pid); 1672static BLK_TRACE_DEVICE_ATTR(start_lba); 1673static BLK_TRACE_DEVICE_ATTR(end_lba); 1674 1675static struct attribute *blk_trace_attrs[] = { 1676 &dev_attr_enable.attr, 1677 &dev_attr_act_mask.attr, 1678 &dev_attr_pid.attr, 1679 &dev_attr_start_lba.attr, 1680 &dev_attr_end_lba.attr, 1681 NULL 1682}; 1683 1684struct attribute_group blk_trace_attr_group = { 1685 .name = "trace", 1686 .attrs = blk_trace_attrs, 1687}; 1688 1689static const struct { 1690 int mask; 1691 const char *str; 1692} mask_maps[] = { 1693 { BLK_TC_READ, "read" }, 1694 { BLK_TC_WRITE, "write" }, 1695 { BLK_TC_FLUSH, "flush" }, 1696 { BLK_TC_SYNC, "sync" }, 1697 { BLK_TC_QUEUE, "queue" }, 1698 { BLK_TC_REQUEUE, "requeue" }, 1699 { BLK_TC_ISSUE, "issue" }, 1700 { BLK_TC_COMPLETE, "complete" }, 1701 { BLK_TC_FS, "fs" }, 1702 { BLK_TC_PC, "pc" }, 1703 { BLK_TC_NOTIFY, "notify" }, 1704 { BLK_TC_AHEAD, "ahead" }, 1705 { BLK_TC_META, "meta" }, 1706 { BLK_TC_DISCARD, "discard" }, 1707 { BLK_TC_DRV_DATA, "drv_data" }, 1708 { BLK_TC_FUA, "fua" }, 1709}; 1710 1711static int blk_trace_str2mask(const char *str) 1712{ 1713 int i; 1714 int mask = 0; 1715 char *buf, *s, *token; 1716 1717 buf = kstrdup(str, GFP_KERNEL); 1718 if (buf == NULL) 1719 return -ENOMEM; 1720 s = strstrip(buf); 1721 1722 while (1) { 1723 token = strsep(&s, ","); 1724 if (token == NULL) 1725 break; 1726 1727 if (*token == '\0') 1728 continue; 1729 1730 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1731 if (strcasecmp(token, mask_maps[i].str) == 0) { 1732 mask |= mask_maps[i].mask; 1733 break; 1734 } 1735 } 1736 if (i == ARRAY_SIZE(mask_maps)) { 1737 mask = -EINVAL; 1738 break; 1739 } 1740 } 1741 kfree(buf); 1742 1743 return mask; 1744} 1745 1746static ssize_t blk_trace_mask2str(char *buf, int mask) 1747{ 1748 int i; 1749 char *p = buf; 1750 1751 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1752 if (mask & mask_maps[i].mask) { 1753 p += sprintf(p, "%s%s", 1754 (p == buf) ? "" : ",", mask_maps[i].str); 1755 } 1756 } 1757 *p++ = '\n'; 1758 1759 return p - buf; 1760} 1761 1762static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1763 struct device_attribute *attr, 1764 char *buf) 1765{ 1766 struct block_device *bdev = dev_to_bdev(dev); 1767 struct request_queue *q = bdev_get_queue(bdev); 1768 struct blk_trace *bt; 1769 ssize_t ret = -ENXIO; 1770 1771 mutex_lock(&q->debugfs_mutex); 1772 1773 bt = rcu_dereference_protected(q->blk_trace, 1774 lockdep_is_held(&q->debugfs_mutex)); 1775 if (attr == &dev_attr_enable) { 1776 ret = sprintf(buf, "%u\n", !!bt); 1777 goto out_unlock_bdev; 1778 } 1779 1780 if (bt == NULL) 1781 ret = sprintf(buf, "disabled\n"); 1782 else if (attr == &dev_attr_act_mask) 1783 ret = blk_trace_mask2str(buf, bt->act_mask); 1784 else if (attr == &dev_attr_pid) 1785 ret = sprintf(buf, "%u\n", bt->pid); 1786 else if (attr == &dev_attr_start_lba) 1787 ret = sprintf(buf, "%llu\n", bt->start_lba); 1788 else if (attr == &dev_attr_end_lba) 1789 ret = sprintf(buf, "%llu\n", bt->end_lba); 1790 1791out_unlock_bdev: 1792 mutex_unlock(&q->debugfs_mutex); 1793 return ret; 1794} 1795 1796static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1797 struct device_attribute *attr, 1798 const char *buf, size_t count) 1799{ 1800 struct block_device *bdev = dev_to_bdev(dev); 1801 struct request_queue *q = bdev_get_queue(bdev); 1802 struct blk_trace *bt; 1803 u64 value; 1804 ssize_t ret = -EINVAL; 1805 1806 if (count == 0) 1807 goto out; 1808 1809 if (attr == &dev_attr_act_mask) { 1810 if (kstrtoull(buf, 0, &value)) { 1811 /* Assume it is a list of trace category names */ 1812 ret = blk_trace_str2mask(buf); 1813 if (ret < 0) 1814 goto out; 1815 value = ret; 1816 } 1817 } else { 1818 if (kstrtoull(buf, 0, &value)) 1819 goto out; 1820 } 1821 1822 mutex_lock(&q->debugfs_mutex); 1823 1824 bt = rcu_dereference_protected(q->blk_trace, 1825 lockdep_is_held(&q->debugfs_mutex)); 1826 if (attr == &dev_attr_enable) { 1827 if (!!value == !!bt) { 1828 ret = 0; 1829 goto out_unlock_bdev; 1830 } 1831 if (value) 1832 ret = blk_trace_setup_queue(q, bdev); 1833 else 1834 ret = blk_trace_remove_queue(q); 1835 goto out_unlock_bdev; 1836 } 1837 1838 ret = 0; 1839 if (bt == NULL) { 1840 ret = blk_trace_setup_queue(q, bdev); 1841 bt = rcu_dereference_protected(q->blk_trace, 1842 lockdep_is_held(&q->debugfs_mutex)); 1843 } 1844 1845 if (ret == 0) { 1846 if (attr == &dev_attr_act_mask) 1847 bt->act_mask = value; 1848 else if (attr == &dev_attr_pid) 1849 bt->pid = value; 1850 else if (attr == &dev_attr_start_lba) 1851 bt->start_lba = value; 1852 else if (attr == &dev_attr_end_lba) 1853 bt->end_lba = value; 1854 } 1855 1856out_unlock_bdev: 1857 mutex_unlock(&q->debugfs_mutex); 1858out: 1859 return ret ? ret : count; 1860} 1861#endif /* CONFIG_BLK_DEV_IO_TRACE */ 1862 1863#ifdef CONFIG_EVENT_TRACING 1864 1865/** 1866 * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string. 1867 * @rwbs: buffer to be filled 1868 * @opf: request operation type (REQ_OP_XXX) and flags for the tracepoint 1869 * 1870 * Description: 1871 * Maps each request operation and flag to a single character and fills the 1872 * buffer provided by the caller with resulting string. 1873 * 1874 **/ 1875void blk_fill_rwbs(char *rwbs, blk_opf_t opf) 1876{ 1877 int i = 0; 1878 1879 if (opf & REQ_PREFLUSH) 1880 rwbs[i++] = 'F'; 1881 1882 switch (opf & REQ_OP_MASK) { 1883 case REQ_OP_WRITE: 1884 rwbs[i++] = 'W'; 1885 break; 1886 case REQ_OP_DISCARD: 1887 rwbs[i++] = 'D'; 1888 break; 1889 case REQ_OP_SECURE_ERASE: 1890 rwbs[i++] = 'D'; 1891 rwbs[i++] = 'E'; 1892 break; 1893 case REQ_OP_FLUSH: 1894 rwbs[i++] = 'F'; 1895 break; 1896 case REQ_OP_READ: 1897 rwbs[i++] = 'R'; 1898 break; 1899 default: 1900 rwbs[i++] = 'N'; 1901 } 1902 1903 if (opf & REQ_FUA) 1904 rwbs[i++] = 'F'; 1905 if (opf & REQ_RAHEAD) 1906 rwbs[i++] = 'A'; 1907 if (opf & REQ_SYNC) 1908 rwbs[i++] = 'S'; 1909 if (opf & REQ_META) 1910 rwbs[i++] = 'M'; 1911 1912 rwbs[i] = '\0'; 1913} 1914EXPORT_SYMBOL_GPL(blk_fill_rwbs); 1915 1916#endif /* CONFIG_EVENT_TRACING */ 1917 1918