1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> 4 * 5 */ 6 #include <linux/kernel.h> 7 #include <linux/blkdev.h> 8 #include <linux/blktrace_api.h> 9 #include <linux/percpu.h> 10 #include <linux/init.h> 11 #include <linux/mutex.h> 12 #include <linux/slab.h> 13 #include <linux/debugfs.h> 14 #include <linux/export.h> 15 #include <linux/time.h> 16 #include <linux/uaccess.h> 17 #include <linux/list.h> 18 #include <linux/blk-cgroup.h> 19 20 #include "../../block/blk.h" 21 22 #include <trace/events/block.h> 23 24 #include "trace_output.h" 25 26 #ifdef CONFIG_BLK_DEV_IO_TRACE 27 28 static unsigned int blktrace_seq __read_mostly = 1; 29 30 static struct trace_array *blk_tr; 31 static bool blk_tracer_enabled __read_mostly; 32 33 static LIST_HEAD(running_trace_list); 34 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock); 35 36 /* Select an alternative, minimalistic output than the original one */ 37 #define TRACE_BLK_OPT_CLASSIC 0x1 38 #define TRACE_BLK_OPT_CGROUP 0x2 39 #define TRACE_BLK_OPT_CGNAME 0x4 40 41 static struct tracer_opt blk_tracer_opts[] = { 42 /* Default disable the minimalistic output */ 43 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, 44 #ifdef CONFIG_BLK_CGROUP 45 { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) }, 46 { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) }, 47 #endif 48 { } 49 }; 50 51 static struct tracer_flags blk_tracer_flags = { 52 .val = 0, 53 .opts = blk_tracer_opts, 54 }; 55 56 /* Global reference count of probes */ 57 static DEFINE_MUTEX(blk_probe_mutex); 58 static int blk_probes_ref; 59 60 static void blk_register_tracepoints(void); 61 static void blk_unregister_tracepoints(void); 62 63 /* 64 * Send out a notify message. 65 */ 66 static void trace_note(struct blk_trace *bt, pid_t pid, int action, 67 const void *data, size_t len, 68 union kernfs_node_id *cgid) 69 { 70 struct blk_io_trace *t; 71 struct ring_buffer_event *event = NULL; 72 struct ring_buffer *buffer = NULL; 73 int pc = 0; 74 int cpu = smp_processor_id(); 75 bool blk_tracer = blk_tracer_enabled; 76 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0; 77 78 if (blk_tracer) { 79 buffer = blk_tr->trace_buffer.buffer; 80 pc = preempt_count(); 81 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 82 sizeof(*t) + len + cgid_len, 83 0, pc); 84 if (!event) 85 return; 86 t = ring_buffer_event_data(event); 87 goto record_it; 88 } 89 90 if (!bt->rchan) 91 return; 92 93 t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len); 94 if (t) { 95 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 96 t->time = ktime_to_ns(ktime_get()); 97 record_it: 98 t->device = bt->dev; 99 t->action = action | (cgid ? __BLK_TN_CGROUP : 0); 100 t->pid = pid; 101 t->cpu = cpu; 102 t->pdu_len = len + cgid_len; 103 if (cgid) 104 memcpy((void *)t + sizeof(*t), cgid, cgid_len); 105 memcpy((void *) t + sizeof(*t) + cgid_len, data, len); 106 107 if (blk_tracer) 108 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc); 109 } 110 } 111 112 /* 113 * Send out a notify for this process, if we haven't done so since a trace 114 * started 115 */ 116 static void trace_note_tsk(struct task_struct *tsk) 117 { 118 unsigned long flags; 119 struct blk_trace *bt; 120 121 tsk->btrace_seq = blktrace_seq; 122 spin_lock_irqsave(&running_trace_lock, flags); 123 list_for_each_entry(bt, &running_trace_list, running_list) { 124 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, 125 sizeof(tsk->comm), NULL); 126 } 127 spin_unlock_irqrestore(&running_trace_lock, flags); 128 } 129 130 static void trace_note_time(struct blk_trace *bt) 131 { 132 struct timespec64 now; 133 unsigned long flags; 134 u32 words[2]; 135 136 /* need to check user space to see if this breaks in y2038 or y2106 */ 137 ktime_get_real_ts64(&now); 138 words[0] = (u32)now.tv_sec; 139 words[1] = now.tv_nsec; 140 141 local_irq_save(flags); 142 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), NULL); 143 local_irq_restore(flags); 144 } 145 146 void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg, 147 const char *fmt, ...) 148 { 149 int n; 150 va_list args; 151 unsigned long flags; 152 char *buf; 153 154 if (unlikely(bt->trace_state != Blktrace_running && 155 !blk_tracer_enabled)) 156 return; 157 158 /* 159 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note 160 * message to the trace. 161 */ 162 if (!(bt->act_mask & BLK_TC_NOTIFY)) 163 return; 164 165 local_irq_save(flags); 166 buf = this_cpu_ptr(bt->msg_data); 167 va_start(args, fmt); 168 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); 169 va_end(args); 170 171 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP)) 172 blkcg = NULL; 173 #ifdef CONFIG_BLK_CGROUP 174 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, 175 blkcg ? cgroup_get_kernfs_id(blkcg->css.cgroup) : NULL); 176 #else 177 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL); 178 #endif 179 local_irq_restore(flags); 180 } 181 EXPORT_SYMBOL_GPL(__trace_note_message); 182 183 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, 184 pid_t pid) 185 { 186 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) 187 return 1; 188 if (sector && (sector < bt->start_lba || sector > bt->end_lba)) 189 return 1; 190 if (bt->pid && pid != bt->pid) 191 return 1; 192 193 return 0; 194 } 195 196 /* 197 * Data direction bit lookup 198 */ 199 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), 200 BLK_TC_ACT(BLK_TC_WRITE) }; 201 202 #define BLK_TC_RAHEAD BLK_TC_AHEAD 203 #define BLK_TC_PREFLUSH BLK_TC_FLUSH 204 205 /* The ilog2() calls fall out because they're constant */ 206 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \ 207 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name)) 208 209 /* 210 * The worker for the various blk_add_trace*() types. Fills out a 211 * blk_io_trace structure and places it in a per-cpu subbuffer. 212 */ 213 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 214 int op, int op_flags, u32 what, int error, int pdu_len, 215 void *pdu_data, union kernfs_node_id *cgid) 216 { 217 struct task_struct *tsk = current; 218 struct ring_buffer_event *event = NULL; 219 struct ring_buffer *buffer = NULL; 220 struct blk_io_trace *t; 221 unsigned long flags = 0; 222 unsigned long *sequence; 223 pid_t pid; 224 int cpu, pc = 0; 225 bool blk_tracer = blk_tracer_enabled; 226 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0; 227 228 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) 229 return; 230 231 what |= ddir_act[op_is_write(op) ? WRITE : READ]; 232 what |= MASK_TC_BIT(op_flags, SYNC); 233 what |= MASK_TC_BIT(op_flags, RAHEAD); 234 what |= MASK_TC_BIT(op_flags, META); 235 what |= MASK_TC_BIT(op_flags, PREFLUSH); 236 what |= MASK_TC_BIT(op_flags, FUA); 237 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE) 238 what |= BLK_TC_ACT(BLK_TC_DISCARD); 239 if (op == REQ_OP_FLUSH) 240 what |= BLK_TC_ACT(BLK_TC_FLUSH); 241 if (cgid) 242 what |= __BLK_TA_CGROUP; 243 244 pid = tsk->pid; 245 if (act_log_check(bt, what, sector, pid)) 246 return; 247 cpu = raw_smp_processor_id(); 248 249 if (blk_tracer) { 250 tracing_record_cmdline(current); 251 252 buffer = blk_tr->trace_buffer.buffer; 253 pc = preempt_count(); 254 event = trace_buffer_lock_reserve(buffer, TRACE_BLK, 255 sizeof(*t) + pdu_len + cgid_len, 256 0, pc); 257 if (!event) 258 return; 259 t = ring_buffer_event_data(event); 260 goto record_it; 261 } 262 263 if (unlikely(tsk->btrace_seq != blktrace_seq)) 264 trace_note_tsk(tsk); 265 266 /* 267 * A word about the locking here - we disable interrupts to reserve 268 * some space in the relay per-cpu buffer, to prevent an irq 269 * from coming in and stepping on our toes. 270 */ 271 local_irq_save(flags); 272 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len); 273 if (t) { 274 sequence = per_cpu_ptr(bt->sequence, cpu); 275 276 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; 277 t->sequence = ++(*sequence); 278 t->time = ktime_to_ns(ktime_get()); 279 record_it: 280 /* 281 * These two are not needed in ftrace as they are in the 282 * generic trace_entry, filled by tracing_generic_entry_update, 283 * but for the trace_event->bin() synthesizer benefit we do it 284 * here too. 285 */ 286 t->cpu = cpu; 287 t->pid = pid; 288 289 t->sector = sector; 290 t->bytes = bytes; 291 t->action = what; 292 t->device = bt->dev; 293 t->error = error; 294 t->pdu_len = pdu_len + cgid_len; 295 296 if (cgid_len) 297 memcpy((void *)t + sizeof(*t), cgid, cgid_len); 298 if (pdu_len) 299 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len); 300 301 if (blk_tracer) { 302 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc); 303 return; 304 } 305 } 306 307 local_irq_restore(flags); 308 } 309 310 static void blk_trace_free(struct blk_trace *bt) 311 { 312 debugfs_remove(bt->msg_file); 313 debugfs_remove(bt->dropped_file); 314 relay_close(bt->rchan); 315 debugfs_remove(bt->dir); 316 free_percpu(bt->sequence); 317 free_percpu(bt->msg_data); 318 kfree(bt); 319 } 320 321 static void get_probe_ref(void) 322 { 323 mutex_lock(&blk_probe_mutex); 324 if (++blk_probes_ref == 1) 325 blk_register_tracepoints(); 326 mutex_unlock(&blk_probe_mutex); 327 } 328 329 static void put_probe_ref(void) 330 { 331 mutex_lock(&blk_probe_mutex); 332 if (!--blk_probes_ref) 333 blk_unregister_tracepoints(); 334 mutex_unlock(&blk_probe_mutex); 335 } 336 337 static void blk_trace_cleanup(struct blk_trace *bt) 338 { 339 blk_trace_free(bt); 340 put_probe_ref(); 341 } 342 343 static int __blk_trace_remove(struct request_queue *q) 344 { 345 struct blk_trace *bt; 346 347 bt = xchg(&q->blk_trace, NULL); 348 if (!bt) 349 return -EINVAL; 350 351 if (bt->trace_state != Blktrace_running) 352 blk_trace_cleanup(bt); 353 354 return 0; 355 } 356 357 int blk_trace_remove(struct request_queue *q) 358 { 359 int ret; 360 361 mutex_lock(&q->blk_trace_mutex); 362 ret = __blk_trace_remove(q); 363 mutex_unlock(&q->blk_trace_mutex); 364 365 return ret; 366 } 367 EXPORT_SYMBOL_GPL(blk_trace_remove); 368 369 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, 370 size_t count, loff_t *ppos) 371 { 372 struct blk_trace *bt = filp->private_data; 373 char buf[16]; 374 375 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); 376 377 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); 378 } 379 380 static const struct file_operations blk_dropped_fops = { 381 .owner = THIS_MODULE, 382 .open = simple_open, 383 .read = blk_dropped_read, 384 .llseek = default_llseek, 385 }; 386 387 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 388 size_t count, loff_t *ppos) 389 { 390 char *msg; 391 struct blk_trace *bt; 392 393 if (count >= BLK_TN_MAX_MSG) 394 return -EINVAL; 395 396 msg = memdup_user_nul(buffer, count); 397 if (IS_ERR(msg)) 398 return PTR_ERR(msg); 399 400 bt = filp->private_data; 401 __trace_note_message(bt, NULL, "%s", msg); 402 kfree(msg); 403 404 return count; 405 } 406 407 static const struct file_operations blk_msg_fops = { 408 .owner = THIS_MODULE, 409 .open = simple_open, 410 .write = blk_msg_write, 411 .llseek = noop_llseek, 412 }; 413 414 /* 415 * Keep track of how many times we encountered a full subbuffer, to aid 416 * the user space app in telling how many lost events there were. 417 */ 418 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, 419 void *prev_subbuf, size_t prev_padding) 420 { 421 struct blk_trace *bt; 422 423 if (!relay_buf_full(buf)) 424 return 1; 425 426 bt = buf->chan->private_data; 427 atomic_inc(&bt->dropped); 428 return 0; 429 } 430 431 static int blk_remove_buf_file_callback(struct dentry *dentry) 432 { 433 debugfs_remove(dentry); 434 435 return 0; 436 } 437 438 static struct dentry *blk_create_buf_file_callback(const char *filename, 439 struct dentry *parent, 440 umode_t mode, 441 struct rchan_buf *buf, 442 int *is_global) 443 { 444 return debugfs_create_file(filename, mode, parent, buf, 445 &relay_file_operations); 446 } 447 448 static struct rchan_callbacks blk_relay_callbacks = { 449 .subbuf_start = blk_subbuf_start_callback, 450 .create_buf_file = blk_create_buf_file_callback, 451 .remove_buf_file = blk_remove_buf_file_callback, 452 }; 453 454 static void blk_trace_setup_lba(struct blk_trace *bt, 455 struct block_device *bdev) 456 { 457 struct hd_struct *part = NULL; 458 459 if (bdev) 460 part = bdev->bd_part; 461 462 if (part) { 463 bt->start_lba = part->start_sect; 464 bt->end_lba = part->start_sect + part->nr_sects; 465 } else { 466 bt->start_lba = 0; 467 bt->end_lba = -1ULL; 468 } 469 } 470 471 /* 472 * Setup everything required to start tracing 473 */ 474 static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 475 struct block_device *bdev, 476 struct blk_user_trace_setup *buts) 477 { 478 struct blk_trace *bt = NULL; 479 struct dentry *dir = NULL; 480 int ret; 481 482 if (!buts->buf_size || !buts->buf_nr) 483 return -EINVAL; 484 485 if (!blk_debugfs_root) 486 return -ENOENT; 487 488 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); 489 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; 490 491 /* 492 * some device names have larger paths - convert the slashes 493 * to underscores for this to work as expected 494 */ 495 strreplace(buts->name, '/', '_'); 496 497 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 498 if (!bt) 499 return -ENOMEM; 500 501 ret = -ENOMEM; 502 bt->sequence = alloc_percpu(unsigned long); 503 if (!bt->sequence) 504 goto err; 505 506 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 507 if (!bt->msg_data) 508 goto err; 509 510 ret = -ENOENT; 511 512 dir = debugfs_lookup(buts->name, blk_debugfs_root); 513 if (!dir) 514 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root); 515 516 bt->dev = dev; 517 atomic_set(&bt->dropped, 0); 518 INIT_LIST_HEAD(&bt->running_list); 519 520 ret = -EIO; 521 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 522 &blk_dropped_fops); 523 524 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 525 526 bt->rchan = relay_open("trace", dir, buts->buf_size, 527 buts->buf_nr, &blk_relay_callbacks, bt); 528 if (!bt->rchan) 529 goto err; 530 531 bt->act_mask = buts->act_mask; 532 if (!bt->act_mask) 533 bt->act_mask = (u16) -1; 534 535 blk_trace_setup_lba(bt, bdev); 536 537 /* overwrite with user settings */ 538 if (buts->start_lba) 539 bt->start_lba = buts->start_lba; 540 if (buts->end_lba) 541 bt->end_lba = buts->end_lba; 542 543 bt->pid = buts->pid; 544 bt->trace_state = Blktrace_setup; 545 546 ret = -EBUSY; 547 if (cmpxchg(&q->blk_trace, NULL, bt)) 548 goto err; 549 550 get_probe_ref(); 551 552 ret = 0; 553 err: 554 if (dir && !bt->dir) 555 dput(dir); 556 if (ret) 557 blk_trace_free(bt); 558 return ret; 559 } 560 561 static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 562 struct block_device *bdev, char __user *arg) 563 { 564 struct blk_user_trace_setup buts; 565 int ret; 566 567 ret = copy_from_user(&buts, arg, sizeof(buts)); 568 if (ret) 569 return -EFAULT; 570 571 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 572 if (ret) 573 return ret; 574 575 if (copy_to_user(arg, &buts, sizeof(buts))) { 576 __blk_trace_remove(q); 577 return -EFAULT; 578 } 579 return 0; 580 } 581 582 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 583 struct block_device *bdev, 584 char __user *arg) 585 { 586 int ret; 587 588 mutex_lock(&q->blk_trace_mutex); 589 ret = __blk_trace_setup(q, name, dev, bdev, arg); 590 mutex_unlock(&q->blk_trace_mutex); 591 592 return ret; 593 } 594 EXPORT_SYMBOL_GPL(blk_trace_setup); 595 596 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 597 static int compat_blk_trace_setup(struct request_queue *q, char *name, 598 dev_t dev, struct block_device *bdev, 599 char __user *arg) 600 { 601 struct blk_user_trace_setup buts; 602 struct compat_blk_user_trace_setup cbuts; 603 int ret; 604 605 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 606 return -EFAULT; 607 608 buts = (struct blk_user_trace_setup) { 609 .act_mask = cbuts.act_mask, 610 .buf_size = cbuts.buf_size, 611 .buf_nr = cbuts.buf_nr, 612 .start_lba = cbuts.start_lba, 613 .end_lba = cbuts.end_lba, 614 .pid = cbuts.pid, 615 }; 616 617 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 618 if (ret) 619 return ret; 620 621 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) { 622 __blk_trace_remove(q); 623 return -EFAULT; 624 } 625 626 return 0; 627 } 628 #endif 629 630 static int __blk_trace_startstop(struct request_queue *q, int start) 631 { 632 int ret; 633 struct blk_trace *bt = q->blk_trace; 634 635 if (bt == NULL) 636 return -EINVAL; 637 638 /* 639 * For starting a trace, we can transition from a setup or stopped 640 * trace. For stopping a trace, the state must be running 641 */ 642 ret = -EINVAL; 643 if (start) { 644 if (bt->trace_state == Blktrace_setup || 645 bt->trace_state == Blktrace_stopped) { 646 blktrace_seq++; 647 smp_mb(); 648 bt->trace_state = Blktrace_running; 649 spin_lock_irq(&running_trace_lock); 650 list_add(&bt->running_list, &running_trace_list); 651 spin_unlock_irq(&running_trace_lock); 652 653 trace_note_time(bt); 654 ret = 0; 655 } 656 } else { 657 if (bt->trace_state == Blktrace_running) { 658 bt->trace_state = Blktrace_stopped; 659 spin_lock_irq(&running_trace_lock); 660 list_del_init(&bt->running_list); 661 spin_unlock_irq(&running_trace_lock); 662 relay_flush(bt->rchan); 663 ret = 0; 664 } 665 } 666 667 return ret; 668 } 669 670 int blk_trace_startstop(struct request_queue *q, int start) 671 { 672 int ret; 673 674 mutex_lock(&q->blk_trace_mutex); 675 ret = __blk_trace_startstop(q, start); 676 mutex_unlock(&q->blk_trace_mutex); 677 678 return ret; 679 } 680 EXPORT_SYMBOL_GPL(blk_trace_startstop); 681 682 /* 683 * When reading or writing the blktrace sysfs files, the references to the 684 * opened sysfs or device files should prevent the underlying block device 685 * from being removed. So no further delete protection is really needed. 686 */ 687 688 /** 689 * blk_trace_ioctl: - handle the ioctls associated with tracing 690 * @bdev: the block device 691 * @cmd: the ioctl cmd 692 * @arg: the argument data, if any 693 * 694 **/ 695 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 696 { 697 struct request_queue *q; 698 int ret, start = 0; 699 char b[BDEVNAME_SIZE]; 700 701 q = bdev_get_queue(bdev); 702 if (!q) 703 return -ENXIO; 704 705 mutex_lock(&q->blk_trace_mutex); 706 707 switch (cmd) { 708 case BLKTRACESETUP: 709 bdevname(bdev, b); 710 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 711 break; 712 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 713 case BLKTRACESETUP32: 714 bdevname(bdev, b); 715 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 716 break; 717 #endif 718 case BLKTRACESTART: 719 start = 1; 720 /* fall through */ 721 case BLKTRACESTOP: 722 ret = __blk_trace_startstop(q, start); 723 break; 724 case BLKTRACETEARDOWN: 725 ret = __blk_trace_remove(q); 726 break; 727 default: 728 ret = -ENOTTY; 729 break; 730 } 731 732 mutex_unlock(&q->blk_trace_mutex); 733 return ret; 734 } 735 736 /** 737 * blk_trace_shutdown: - stop and cleanup trace structures 738 * @q: the request queue associated with the device 739 * 740 **/ 741 void blk_trace_shutdown(struct request_queue *q) 742 { 743 mutex_lock(&q->blk_trace_mutex); 744 745 if (q->blk_trace) { 746 __blk_trace_startstop(q, 0); 747 __blk_trace_remove(q); 748 } 749 750 mutex_unlock(&q->blk_trace_mutex); 751 } 752 753 #ifdef CONFIG_BLK_CGROUP 754 static union kernfs_node_id * 755 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) 756 { 757 struct blk_trace *bt = q->blk_trace; 758 759 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP)) 760 return NULL; 761 762 if (!bio->bi_blkg) 763 return NULL; 764 return cgroup_get_kernfs_id(bio_blkcg(bio)->css.cgroup); 765 } 766 #else 767 static union kernfs_node_id * 768 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) 769 { 770 return NULL; 771 } 772 #endif 773 774 static union kernfs_node_id * 775 blk_trace_request_get_cgid(struct request_queue *q, struct request *rq) 776 { 777 if (!rq->bio) 778 return NULL; 779 /* Use the first bio */ 780 return blk_trace_bio_get_cgid(q, rq->bio); 781 } 782 783 /* 784 * blktrace probes 785 */ 786 787 /** 788 * blk_add_trace_rq - Add a trace for a request oriented action 789 * @rq: the source request 790 * @error: return status to log 791 * @nr_bytes: number of completed bytes 792 * @what: the action 793 * @cgid: the cgroup info 794 * 795 * Description: 796 * Records an action against a request. Will log the bio offset + size. 797 * 798 **/ 799 static void blk_add_trace_rq(struct request *rq, int error, 800 unsigned int nr_bytes, u32 what, 801 union kernfs_node_id *cgid) 802 { 803 struct blk_trace *bt = rq->q->blk_trace; 804 805 if (likely(!bt)) 806 return; 807 808 if (blk_rq_is_passthrough(rq)) 809 what |= BLK_TC_ACT(BLK_TC_PC); 810 else 811 what |= BLK_TC_ACT(BLK_TC_FS); 812 813 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq), 814 rq->cmd_flags, what, error, 0, NULL, cgid); 815 } 816 817 static void blk_add_trace_rq_insert(void *ignore, 818 struct request_queue *q, struct request *rq) 819 { 820 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT, 821 blk_trace_request_get_cgid(q, rq)); 822 } 823 824 static void blk_add_trace_rq_issue(void *ignore, 825 struct request_queue *q, struct request *rq) 826 { 827 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE, 828 blk_trace_request_get_cgid(q, rq)); 829 } 830 831 static void blk_add_trace_rq_requeue(void *ignore, 832 struct request_queue *q, 833 struct request *rq) 834 { 835 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE, 836 blk_trace_request_get_cgid(q, rq)); 837 } 838 839 static void blk_add_trace_rq_complete(void *ignore, struct request *rq, 840 int error, unsigned int nr_bytes) 841 { 842 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE, 843 blk_trace_request_get_cgid(rq->q, rq)); 844 } 845 846 /** 847 * blk_add_trace_bio - Add a trace for a bio oriented action 848 * @q: queue the io is for 849 * @bio: the source bio 850 * @what: the action 851 * @error: error, if any 852 * 853 * Description: 854 * Records an action against a bio. Will log the bio offset + size. 855 * 856 **/ 857 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 858 u32 what, int error) 859 { 860 struct blk_trace *bt = q->blk_trace; 861 862 if (likely(!bt)) 863 return; 864 865 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 866 bio_op(bio), bio->bi_opf, what, error, 0, NULL, 867 blk_trace_bio_get_cgid(q, bio)); 868 } 869 870 static void blk_add_trace_bio_bounce(void *ignore, 871 struct request_queue *q, struct bio *bio) 872 { 873 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0); 874 } 875 876 static void blk_add_trace_bio_complete(void *ignore, 877 struct request_queue *q, struct bio *bio, 878 int error) 879 { 880 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error); 881 } 882 883 static void blk_add_trace_bio_backmerge(void *ignore, 884 struct request_queue *q, 885 struct request *rq, 886 struct bio *bio) 887 { 888 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0); 889 } 890 891 static void blk_add_trace_bio_frontmerge(void *ignore, 892 struct request_queue *q, 893 struct request *rq, 894 struct bio *bio) 895 { 896 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0); 897 } 898 899 static void blk_add_trace_bio_queue(void *ignore, 900 struct request_queue *q, struct bio *bio) 901 { 902 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0); 903 } 904 905 static void blk_add_trace_getrq(void *ignore, 906 struct request_queue *q, 907 struct bio *bio, int rw) 908 { 909 if (bio) 910 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0); 911 else { 912 struct blk_trace *bt = q->blk_trace; 913 914 if (bt) 915 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0, 916 NULL, NULL); 917 } 918 } 919 920 921 static void blk_add_trace_sleeprq(void *ignore, 922 struct request_queue *q, 923 struct bio *bio, int rw) 924 { 925 if (bio) 926 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0); 927 else { 928 struct blk_trace *bt = q->blk_trace; 929 930 if (bt) 931 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ, 932 0, 0, NULL, NULL); 933 } 934 } 935 936 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 937 { 938 struct blk_trace *bt = q->blk_trace; 939 940 if (bt) 941 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, NULL); 942 } 943 944 static void blk_add_trace_unplug(void *ignore, struct request_queue *q, 945 unsigned int depth, bool explicit) 946 { 947 struct blk_trace *bt = q->blk_trace; 948 949 if (bt) { 950 __be64 rpdu = cpu_to_be64(depth); 951 u32 what; 952 953 if (explicit) 954 what = BLK_TA_UNPLUG_IO; 955 else 956 what = BLK_TA_UNPLUG_TIMER; 957 958 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, NULL); 959 } 960 } 961 962 static void blk_add_trace_split(void *ignore, 963 struct request_queue *q, struct bio *bio, 964 unsigned int pdu) 965 { 966 struct blk_trace *bt = q->blk_trace; 967 968 if (bt) { 969 __be64 rpdu = cpu_to_be64(pdu); 970 971 __blk_add_trace(bt, bio->bi_iter.bi_sector, 972 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf, 973 BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu), 974 &rpdu, blk_trace_bio_get_cgid(q, bio)); 975 } 976 } 977 978 /** 979 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation 980 * @ignore: trace callback data parameter (not used) 981 * @q: queue the io is for 982 * @bio: the source bio 983 * @dev: target device 984 * @from: source sector 985 * 986 * Description: 987 * Device mapper or raid target sometimes need to split a bio because 988 * it spans a stripe (or similar). Add a trace for that action. 989 * 990 **/ 991 static void blk_add_trace_bio_remap(void *ignore, 992 struct request_queue *q, struct bio *bio, 993 dev_t dev, sector_t from) 994 { 995 struct blk_trace *bt = q->blk_trace; 996 struct blk_io_trace_remap r; 997 998 if (likely(!bt)) 999 return; 1000 1001 r.device_from = cpu_to_be32(dev); 1002 r.device_to = cpu_to_be32(bio_dev(bio)); 1003 r.sector_from = cpu_to_be64(from); 1004 1005 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 1006 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status, 1007 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio)); 1008 } 1009 1010 /** 1011 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 1012 * @ignore: trace callback data parameter (not used) 1013 * @q: queue the io is for 1014 * @rq: the source request 1015 * @dev: target device 1016 * @from: source sector 1017 * 1018 * Description: 1019 * Device mapper remaps request to other devices. 1020 * Add a trace for that action. 1021 * 1022 **/ 1023 static void blk_add_trace_rq_remap(void *ignore, 1024 struct request_queue *q, 1025 struct request *rq, dev_t dev, 1026 sector_t from) 1027 { 1028 struct blk_trace *bt = q->blk_trace; 1029 struct blk_io_trace_remap r; 1030 1031 if (likely(!bt)) 1032 return; 1033 1034 r.device_from = cpu_to_be32(dev); 1035 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 1036 r.sector_from = cpu_to_be64(from); 1037 1038 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 1039 rq_data_dir(rq), 0, BLK_TA_REMAP, 0, 1040 sizeof(r), &r, blk_trace_request_get_cgid(q, rq)); 1041 } 1042 1043 /** 1044 * blk_add_driver_data - Add binary message with driver-specific data 1045 * @q: queue the io is for 1046 * @rq: io request 1047 * @data: driver-specific data 1048 * @len: length of driver-specific data 1049 * 1050 * Description: 1051 * Some drivers might want to write driver-specific data per request. 1052 * 1053 **/ 1054 void blk_add_driver_data(struct request_queue *q, 1055 struct request *rq, 1056 void *data, size_t len) 1057 { 1058 struct blk_trace *bt = q->blk_trace; 1059 1060 if (likely(!bt)) 1061 return; 1062 1063 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0, 1064 BLK_TA_DRV_DATA, 0, len, data, 1065 blk_trace_request_get_cgid(q, rq)); 1066 } 1067 EXPORT_SYMBOL_GPL(blk_add_driver_data); 1068 1069 static void blk_register_tracepoints(void) 1070 { 1071 int ret; 1072 1073 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1074 WARN_ON(ret); 1075 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1076 WARN_ON(ret); 1077 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1078 WARN_ON(ret); 1079 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1080 WARN_ON(ret); 1081 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1082 WARN_ON(ret); 1083 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1084 WARN_ON(ret); 1085 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1086 WARN_ON(ret); 1087 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1088 WARN_ON(ret); 1089 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1090 WARN_ON(ret); 1091 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 1092 WARN_ON(ret); 1093 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1094 WARN_ON(ret); 1095 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 1096 WARN_ON(ret); 1097 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL); 1098 WARN_ON(ret); 1099 ret = register_trace_block_split(blk_add_trace_split, NULL); 1100 WARN_ON(ret); 1101 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1102 WARN_ON(ret); 1103 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1104 WARN_ON(ret); 1105 } 1106 1107 static void blk_unregister_tracepoints(void) 1108 { 1109 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1110 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1111 unregister_trace_block_split(blk_add_trace_split, NULL); 1112 unregister_trace_block_unplug(blk_add_trace_unplug, NULL); 1113 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1114 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1115 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1116 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1117 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1118 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1119 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1120 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1121 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1122 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1123 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1124 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1125 1126 tracepoint_synchronize_unregister(); 1127 } 1128 1129 /* 1130 * struct blk_io_tracer formatting routines 1131 */ 1132 1133 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1134 { 1135 int i = 0; 1136 int tc = t->action >> BLK_TC_SHIFT; 1137 1138 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { 1139 rwbs[i++] = 'N'; 1140 goto out; 1141 } 1142 1143 if (tc & BLK_TC_FLUSH) 1144 rwbs[i++] = 'F'; 1145 1146 if (tc & BLK_TC_DISCARD) 1147 rwbs[i++] = 'D'; 1148 else if (tc & BLK_TC_WRITE) 1149 rwbs[i++] = 'W'; 1150 else if (t->bytes) 1151 rwbs[i++] = 'R'; 1152 else 1153 rwbs[i++] = 'N'; 1154 1155 if (tc & BLK_TC_FUA) 1156 rwbs[i++] = 'F'; 1157 if (tc & BLK_TC_AHEAD) 1158 rwbs[i++] = 'A'; 1159 if (tc & BLK_TC_SYNC) 1160 rwbs[i++] = 'S'; 1161 if (tc & BLK_TC_META) 1162 rwbs[i++] = 'M'; 1163 out: 1164 rwbs[i] = '\0'; 1165 } 1166 1167 static inline 1168 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1169 { 1170 return (const struct blk_io_trace *)ent; 1171 } 1172 1173 static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg) 1174 { 1175 return (void *)(te_blk_io_trace(ent) + 1) + 1176 (has_cg ? sizeof(union kernfs_node_id) : 0); 1177 } 1178 1179 static inline const void *cgid_start(const struct trace_entry *ent) 1180 { 1181 return (void *)(te_blk_io_trace(ent) + 1); 1182 } 1183 1184 static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg) 1185 { 1186 return te_blk_io_trace(ent)->pdu_len - 1187 (has_cg ? sizeof(union kernfs_node_id) : 0); 1188 } 1189 1190 static inline u32 t_action(const struct trace_entry *ent) 1191 { 1192 return te_blk_io_trace(ent)->action; 1193 } 1194 1195 static inline u32 t_bytes(const struct trace_entry *ent) 1196 { 1197 return te_blk_io_trace(ent)->bytes; 1198 } 1199 1200 static inline u32 t_sec(const struct trace_entry *ent) 1201 { 1202 return te_blk_io_trace(ent)->bytes >> 9; 1203 } 1204 1205 static inline unsigned long long t_sector(const struct trace_entry *ent) 1206 { 1207 return te_blk_io_trace(ent)->sector; 1208 } 1209 1210 static inline __u16 t_error(const struct trace_entry *ent) 1211 { 1212 return te_blk_io_trace(ent)->error; 1213 } 1214 1215 static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg) 1216 { 1217 const __u64 *val = pdu_start(ent, has_cg); 1218 return be64_to_cpu(*val); 1219 } 1220 1221 static void get_pdu_remap(const struct trace_entry *ent, 1222 struct blk_io_trace_remap *r, bool has_cg) 1223 { 1224 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg); 1225 __u64 sector_from = __r->sector_from; 1226 1227 r->device_from = be32_to_cpu(__r->device_from); 1228 r->device_to = be32_to_cpu(__r->device_to); 1229 r->sector_from = be64_to_cpu(sector_from); 1230 } 1231 1232 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act, 1233 bool has_cg); 1234 1235 static void blk_log_action_classic(struct trace_iterator *iter, const char *act, 1236 bool has_cg) 1237 { 1238 char rwbs[RWBS_LEN]; 1239 unsigned long long ts = iter->ts; 1240 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1241 unsigned secs = (unsigned long)ts; 1242 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1243 1244 fill_rwbs(rwbs, t); 1245 1246 trace_seq_printf(&iter->seq, 1247 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1248 MAJOR(t->device), MINOR(t->device), iter->cpu, 1249 secs, nsec_rem, iter->ent->pid, act, rwbs); 1250 } 1251 1252 static void blk_log_action(struct trace_iterator *iter, const char *act, 1253 bool has_cg) 1254 { 1255 char rwbs[RWBS_LEN]; 1256 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1257 1258 fill_rwbs(rwbs, t); 1259 if (has_cg) { 1260 const union kernfs_node_id *id = cgid_start(iter->ent); 1261 1262 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) { 1263 char blkcg_name_buf[NAME_MAX + 1] = "<...>"; 1264 1265 cgroup_path_from_kernfs_id(id, blkcg_name_buf, 1266 sizeof(blkcg_name_buf)); 1267 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ", 1268 MAJOR(t->device), MINOR(t->device), 1269 blkcg_name_buf, act, rwbs); 1270 } else 1271 trace_seq_printf(&iter->seq, 1272 "%3d,%-3d %x,%-x %2s %3s ", 1273 MAJOR(t->device), MINOR(t->device), 1274 id->ino, id->generation, act, rwbs); 1275 } else 1276 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1277 MAJOR(t->device), MINOR(t->device), act, rwbs); 1278 } 1279 1280 static void blk_log_dump_pdu(struct trace_seq *s, 1281 const struct trace_entry *ent, bool has_cg) 1282 { 1283 const unsigned char *pdu_buf; 1284 int pdu_len; 1285 int i, end; 1286 1287 pdu_buf = pdu_start(ent, has_cg); 1288 pdu_len = pdu_real_len(ent, has_cg); 1289 1290 if (!pdu_len) 1291 return; 1292 1293 /* find the last zero that needs to be printed */ 1294 for (end = pdu_len - 1; end >= 0; end--) 1295 if (pdu_buf[end]) 1296 break; 1297 end++; 1298 1299 trace_seq_putc(s, '('); 1300 1301 for (i = 0; i < pdu_len; i++) { 1302 1303 trace_seq_printf(s, "%s%02x", 1304 i == 0 ? "" : " ", pdu_buf[i]); 1305 1306 /* 1307 * stop when the rest is just zeroes and indicate so 1308 * with a ".." appended 1309 */ 1310 if (i == end && end != pdu_len - 1) { 1311 trace_seq_puts(s, " ..) "); 1312 return; 1313 } 1314 } 1315 1316 trace_seq_puts(s, ") "); 1317 } 1318 1319 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1320 { 1321 char cmd[TASK_COMM_LEN]; 1322 1323 trace_find_cmdline(ent->pid, cmd); 1324 1325 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1326 trace_seq_printf(s, "%u ", t_bytes(ent)); 1327 blk_log_dump_pdu(s, ent, has_cg); 1328 trace_seq_printf(s, "[%s]\n", cmd); 1329 } else { 1330 if (t_sec(ent)) 1331 trace_seq_printf(s, "%llu + %u [%s]\n", 1332 t_sector(ent), t_sec(ent), cmd); 1333 else 1334 trace_seq_printf(s, "[%s]\n", cmd); 1335 } 1336 } 1337 1338 static void blk_log_with_error(struct trace_seq *s, 1339 const struct trace_entry *ent, bool has_cg) 1340 { 1341 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1342 blk_log_dump_pdu(s, ent, has_cg); 1343 trace_seq_printf(s, "[%d]\n", t_error(ent)); 1344 } else { 1345 if (t_sec(ent)) 1346 trace_seq_printf(s, "%llu + %u [%d]\n", 1347 t_sector(ent), 1348 t_sec(ent), t_error(ent)); 1349 else 1350 trace_seq_printf(s, "%llu [%d]\n", 1351 t_sector(ent), t_error(ent)); 1352 } 1353 } 1354 1355 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1356 { 1357 struct blk_io_trace_remap r = { .device_from = 0, }; 1358 1359 get_pdu_remap(ent, &r, has_cg); 1360 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1361 t_sector(ent), t_sec(ent), 1362 MAJOR(r.device_from), MINOR(r.device_from), 1363 (unsigned long long)r.sector_from); 1364 } 1365 1366 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1367 { 1368 char cmd[TASK_COMM_LEN]; 1369 1370 trace_find_cmdline(ent->pid, cmd); 1371 1372 trace_seq_printf(s, "[%s]\n", cmd); 1373 } 1374 1375 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1376 { 1377 char cmd[TASK_COMM_LEN]; 1378 1379 trace_find_cmdline(ent->pid, cmd); 1380 1381 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg)); 1382 } 1383 1384 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1385 { 1386 char cmd[TASK_COMM_LEN]; 1387 1388 trace_find_cmdline(ent->pid, cmd); 1389 1390 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1391 get_pdu_int(ent, has_cg), cmd); 1392 } 1393 1394 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent, 1395 bool has_cg) 1396 { 1397 1398 trace_seq_putmem(s, pdu_start(ent, has_cg), 1399 pdu_real_len(ent, has_cg)); 1400 trace_seq_putc(s, '\n'); 1401 } 1402 1403 /* 1404 * struct tracer operations 1405 */ 1406 1407 static void blk_tracer_print_header(struct seq_file *m) 1408 { 1409 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1410 return; 1411 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1412 "# | | | | | |\n"); 1413 } 1414 1415 static void blk_tracer_start(struct trace_array *tr) 1416 { 1417 blk_tracer_enabled = true; 1418 } 1419 1420 static int blk_tracer_init(struct trace_array *tr) 1421 { 1422 blk_tr = tr; 1423 blk_tracer_start(tr); 1424 return 0; 1425 } 1426 1427 static void blk_tracer_stop(struct trace_array *tr) 1428 { 1429 blk_tracer_enabled = false; 1430 } 1431 1432 static void blk_tracer_reset(struct trace_array *tr) 1433 { 1434 blk_tracer_stop(tr); 1435 } 1436 1437 static const struct { 1438 const char *act[2]; 1439 void (*print)(struct trace_seq *s, const struct trace_entry *ent, 1440 bool has_cg); 1441 } what2act[] = { 1442 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1443 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1444 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1445 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1446 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1447 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1448 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1449 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1450 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1451 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1452 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1453 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1454 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1455 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1456 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1457 }; 1458 1459 static enum print_line_t print_one_line(struct trace_iterator *iter, 1460 bool classic) 1461 { 1462 struct trace_array *tr = iter->tr; 1463 struct trace_seq *s = &iter->seq; 1464 const struct blk_io_trace *t; 1465 u16 what; 1466 bool long_act; 1467 blk_log_action_t *log_action; 1468 bool has_cg; 1469 1470 t = te_blk_io_trace(iter->ent); 1471 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP; 1472 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE); 1473 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1474 has_cg = t->action & __BLK_TA_CGROUP; 1475 1476 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { 1477 log_action(iter, long_act ? "message" : "m", has_cg); 1478 blk_log_msg(s, iter->ent, has_cg); 1479 return trace_handle_return(s); 1480 } 1481 1482 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1483 trace_seq_printf(s, "Unknown action %x\n", what); 1484 else { 1485 log_action(iter, what2act[what].act[long_act], has_cg); 1486 what2act[what].print(s, iter->ent, has_cg); 1487 } 1488 1489 return trace_handle_return(s); 1490 } 1491 1492 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1493 int flags, struct trace_event *event) 1494 { 1495 return print_one_line(iter, false); 1496 } 1497 1498 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1499 { 1500 struct trace_seq *s = &iter->seq; 1501 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1502 const int offset = offsetof(struct blk_io_trace, sector); 1503 struct blk_io_trace old = { 1504 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1505 .time = iter->ts, 1506 }; 1507 1508 trace_seq_putmem(s, &old, offset); 1509 trace_seq_putmem(s, &t->sector, 1510 sizeof(old) - offset + t->pdu_len); 1511 } 1512 1513 static enum print_line_t 1514 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1515 struct trace_event *event) 1516 { 1517 blk_trace_synthesize_old_trace(iter); 1518 1519 return trace_handle_return(&iter->seq); 1520 } 1521 1522 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1523 { 1524 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1525 return TRACE_TYPE_UNHANDLED; 1526 1527 return print_one_line(iter, true); 1528 } 1529 1530 static int 1531 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) 1532 { 1533 /* don't output context-info for blk_classic output */ 1534 if (bit == TRACE_BLK_OPT_CLASSIC) { 1535 if (set) 1536 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1537 else 1538 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO; 1539 } 1540 return 0; 1541 } 1542 1543 static struct tracer blk_tracer __read_mostly = { 1544 .name = "blk", 1545 .init = blk_tracer_init, 1546 .reset = blk_tracer_reset, 1547 .start = blk_tracer_start, 1548 .stop = blk_tracer_stop, 1549 .print_header = blk_tracer_print_header, 1550 .print_line = blk_tracer_print_line, 1551 .flags = &blk_tracer_flags, 1552 .set_flag = blk_tracer_set_flag, 1553 }; 1554 1555 static struct trace_event_functions trace_blk_event_funcs = { 1556 .trace = blk_trace_event_print, 1557 .binary = blk_trace_event_print_binary, 1558 }; 1559 1560 static struct trace_event trace_blk_event = { 1561 .type = TRACE_BLK, 1562 .funcs = &trace_blk_event_funcs, 1563 }; 1564 1565 static int __init init_blk_tracer(void) 1566 { 1567 if (!register_trace_event(&trace_blk_event)) { 1568 pr_warn("Warning: could not register block events\n"); 1569 return 1; 1570 } 1571 1572 if (register_tracer(&blk_tracer) != 0) { 1573 pr_warn("Warning: could not register the block tracer\n"); 1574 unregister_trace_event(&trace_blk_event); 1575 return 1; 1576 } 1577 1578 return 0; 1579 } 1580 1581 device_initcall(init_blk_tracer); 1582 1583 static int blk_trace_remove_queue(struct request_queue *q) 1584 { 1585 struct blk_trace *bt; 1586 1587 bt = xchg(&q->blk_trace, NULL); 1588 if (bt == NULL) 1589 return -EINVAL; 1590 1591 put_probe_ref(); 1592 blk_trace_free(bt); 1593 return 0; 1594 } 1595 1596 /* 1597 * Setup everything required to start tracing 1598 */ 1599 static int blk_trace_setup_queue(struct request_queue *q, 1600 struct block_device *bdev) 1601 { 1602 struct blk_trace *bt = NULL; 1603 int ret = -ENOMEM; 1604 1605 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1606 if (!bt) 1607 return -ENOMEM; 1608 1609 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1610 if (!bt->msg_data) 1611 goto free_bt; 1612 1613 bt->dev = bdev->bd_dev; 1614 bt->act_mask = (u16)-1; 1615 1616 blk_trace_setup_lba(bt, bdev); 1617 1618 ret = -EBUSY; 1619 if (cmpxchg(&q->blk_trace, NULL, bt)) 1620 goto free_bt; 1621 1622 get_probe_ref(); 1623 return 0; 1624 1625 free_bt: 1626 blk_trace_free(bt); 1627 return ret; 1628 } 1629 1630 /* 1631 * sysfs interface to enable and configure tracing 1632 */ 1633 1634 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1635 struct device_attribute *attr, 1636 char *buf); 1637 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1638 struct device_attribute *attr, 1639 const char *buf, size_t count); 1640 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1641 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1642 sysfs_blk_trace_attr_show, \ 1643 sysfs_blk_trace_attr_store) 1644 1645 static BLK_TRACE_DEVICE_ATTR(enable); 1646 static BLK_TRACE_DEVICE_ATTR(act_mask); 1647 static BLK_TRACE_DEVICE_ATTR(pid); 1648 static BLK_TRACE_DEVICE_ATTR(start_lba); 1649 static BLK_TRACE_DEVICE_ATTR(end_lba); 1650 1651 static struct attribute *blk_trace_attrs[] = { 1652 &dev_attr_enable.attr, 1653 &dev_attr_act_mask.attr, 1654 &dev_attr_pid.attr, 1655 &dev_attr_start_lba.attr, 1656 &dev_attr_end_lba.attr, 1657 NULL 1658 }; 1659 1660 struct attribute_group blk_trace_attr_group = { 1661 .name = "trace", 1662 .attrs = blk_trace_attrs, 1663 }; 1664 1665 static const struct { 1666 int mask; 1667 const char *str; 1668 } mask_maps[] = { 1669 { BLK_TC_READ, "read" }, 1670 { BLK_TC_WRITE, "write" }, 1671 { BLK_TC_FLUSH, "flush" }, 1672 { BLK_TC_SYNC, "sync" }, 1673 { BLK_TC_QUEUE, "queue" }, 1674 { BLK_TC_REQUEUE, "requeue" }, 1675 { BLK_TC_ISSUE, "issue" }, 1676 { BLK_TC_COMPLETE, "complete" }, 1677 { BLK_TC_FS, "fs" }, 1678 { BLK_TC_PC, "pc" }, 1679 { BLK_TC_NOTIFY, "notify" }, 1680 { BLK_TC_AHEAD, "ahead" }, 1681 { BLK_TC_META, "meta" }, 1682 { BLK_TC_DISCARD, "discard" }, 1683 { BLK_TC_DRV_DATA, "drv_data" }, 1684 { BLK_TC_FUA, "fua" }, 1685 }; 1686 1687 static int blk_trace_str2mask(const char *str) 1688 { 1689 int i; 1690 int mask = 0; 1691 char *buf, *s, *token; 1692 1693 buf = kstrdup(str, GFP_KERNEL); 1694 if (buf == NULL) 1695 return -ENOMEM; 1696 s = strstrip(buf); 1697 1698 while (1) { 1699 token = strsep(&s, ","); 1700 if (token == NULL) 1701 break; 1702 1703 if (*token == '\0') 1704 continue; 1705 1706 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1707 if (strcasecmp(token, mask_maps[i].str) == 0) { 1708 mask |= mask_maps[i].mask; 1709 break; 1710 } 1711 } 1712 if (i == ARRAY_SIZE(mask_maps)) { 1713 mask = -EINVAL; 1714 break; 1715 } 1716 } 1717 kfree(buf); 1718 1719 return mask; 1720 } 1721 1722 static ssize_t blk_trace_mask2str(char *buf, int mask) 1723 { 1724 int i; 1725 char *p = buf; 1726 1727 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1728 if (mask & mask_maps[i].mask) { 1729 p += sprintf(p, "%s%s", 1730 (p == buf) ? "" : ",", mask_maps[i].str); 1731 } 1732 } 1733 *p++ = '\n'; 1734 1735 return p - buf; 1736 } 1737 1738 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1739 { 1740 if (bdev->bd_disk == NULL) 1741 return NULL; 1742 1743 return bdev_get_queue(bdev); 1744 } 1745 1746 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1747 struct device_attribute *attr, 1748 char *buf) 1749 { 1750 struct hd_struct *p = dev_to_part(dev); 1751 struct request_queue *q; 1752 struct block_device *bdev; 1753 ssize_t ret = -ENXIO; 1754 1755 bdev = bdget(part_devt(p)); 1756 if (bdev == NULL) 1757 goto out; 1758 1759 q = blk_trace_get_queue(bdev); 1760 if (q == NULL) 1761 goto out_bdput; 1762 1763 mutex_lock(&q->blk_trace_mutex); 1764 1765 if (attr == &dev_attr_enable) { 1766 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1767 goto out_unlock_bdev; 1768 } 1769 1770 if (q->blk_trace == NULL) 1771 ret = sprintf(buf, "disabled\n"); 1772 else if (attr == &dev_attr_act_mask) 1773 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1774 else if (attr == &dev_attr_pid) 1775 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1776 else if (attr == &dev_attr_start_lba) 1777 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1778 else if (attr == &dev_attr_end_lba) 1779 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1780 1781 out_unlock_bdev: 1782 mutex_unlock(&q->blk_trace_mutex); 1783 out_bdput: 1784 bdput(bdev); 1785 out: 1786 return ret; 1787 } 1788 1789 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1790 struct device_attribute *attr, 1791 const char *buf, size_t count) 1792 { 1793 struct block_device *bdev; 1794 struct request_queue *q; 1795 struct hd_struct *p; 1796 u64 value; 1797 ssize_t ret = -EINVAL; 1798 1799 if (count == 0) 1800 goto out; 1801 1802 if (attr == &dev_attr_act_mask) { 1803 if (kstrtoull(buf, 0, &value)) { 1804 /* Assume it is a list of trace category names */ 1805 ret = blk_trace_str2mask(buf); 1806 if (ret < 0) 1807 goto out; 1808 value = ret; 1809 } 1810 } else if (kstrtoull(buf, 0, &value)) 1811 goto out; 1812 1813 ret = -ENXIO; 1814 1815 p = dev_to_part(dev); 1816 bdev = bdget(part_devt(p)); 1817 if (bdev == NULL) 1818 goto out; 1819 1820 q = blk_trace_get_queue(bdev); 1821 if (q == NULL) 1822 goto out_bdput; 1823 1824 mutex_lock(&q->blk_trace_mutex); 1825 1826 if (attr == &dev_attr_enable) { 1827 if (!!value == !!q->blk_trace) { 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 (q->blk_trace == NULL) 1840 ret = blk_trace_setup_queue(q, bdev); 1841 1842 if (ret == 0) { 1843 if (attr == &dev_attr_act_mask) 1844 q->blk_trace->act_mask = value; 1845 else if (attr == &dev_attr_pid) 1846 q->blk_trace->pid = value; 1847 else if (attr == &dev_attr_start_lba) 1848 q->blk_trace->start_lba = value; 1849 else if (attr == &dev_attr_end_lba) 1850 q->blk_trace->end_lba = value; 1851 } 1852 1853 out_unlock_bdev: 1854 mutex_unlock(&q->blk_trace_mutex); 1855 out_bdput: 1856 bdput(bdev); 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 void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes) 1876 { 1877 int i = 0; 1878 1879 if (op & REQ_PREFLUSH) 1880 rwbs[i++] = 'F'; 1881 1882 switch (op & REQ_OP_MASK) { 1883 case REQ_OP_WRITE: 1884 case REQ_OP_WRITE_SAME: 1885 rwbs[i++] = 'W'; 1886 break; 1887 case REQ_OP_DISCARD: 1888 rwbs[i++] = 'D'; 1889 break; 1890 case REQ_OP_SECURE_ERASE: 1891 rwbs[i++] = 'D'; 1892 rwbs[i++] = 'E'; 1893 break; 1894 case REQ_OP_FLUSH: 1895 rwbs[i++] = 'F'; 1896 break; 1897 case REQ_OP_READ: 1898 rwbs[i++] = 'R'; 1899 break; 1900 default: 1901 rwbs[i++] = 'N'; 1902 } 1903 1904 if (op & REQ_FUA) 1905 rwbs[i++] = 'F'; 1906 if (op & REQ_RAHEAD) 1907 rwbs[i++] = 'A'; 1908 if (op & REQ_SYNC) 1909 rwbs[i++] = 'S'; 1910 if (op & REQ_META) 1911 rwbs[i++] = 'M'; 1912 1913 rwbs[i] = '\0'; 1914 } 1915 EXPORT_SYMBOL_GPL(blk_fill_rwbs); 1916 1917 #endif /* CONFIG_EVENT_TRACING */ 1918 1919