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 if (!dir) 516 goto err; 517 518 bt->dev = dev; 519 atomic_set(&bt->dropped, 0); 520 INIT_LIST_HEAD(&bt->running_list); 521 522 ret = -EIO; 523 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, 524 &blk_dropped_fops); 525 if (!bt->dropped_file) 526 goto err; 527 528 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); 529 if (!bt->msg_file) 530 goto err; 531 532 bt->rchan = relay_open("trace", dir, buts->buf_size, 533 buts->buf_nr, &blk_relay_callbacks, bt); 534 if (!bt->rchan) 535 goto err; 536 537 bt->act_mask = buts->act_mask; 538 if (!bt->act_mask) 539 bt->act_mask = (u16) -1; 540 541 blk_trace_setup_lba(bt, bdev); 542 543 /* overwrite with user settings */ 544 if (buts->start_lba) 545 bt->start_lba = buts->start_lba; 546 if (buts->end_lba) 547 bt->end_lba = buts->end_lba; 548 549 bt->pid = buts->pid; 550 bt->trace_state = Blktrace_setup; 551 552 ret = -EBUSY; 553 if (cmpxchg(&q->blk_trace, NULL, bt)) 554 goto err; 555 556 get_probe_ref(); 557 558 ret = 0; 559 err: 560 if (dir && !bt->dir) 561 dput(dir); 562 if (ret) 563 blk_trace_free(bt); 564 return ret; 565 } 566 567 static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 568 struct block_device *bdev, char __user *arg) 569 { 570 struct blk_user_trace_setup buts; 571 int ret; 572 573 ret = copy_from_user(&buts, arg, sizeof(buts)); 574 if (ret) 575 return -EFAULT; 576 577 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 578 if (ret) 579 return ret; 580 581 if (copy_to_user(arg, &buts, sizeof(buts))) { 582 __blk_trace_remove(q); 583 return -EFAULT; 584 } 585 return 0; 586 } 587 588 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 589 struct block_device *bdev, 590 char __user *arg) 591 { 592 int ret; 593 594 mutex_lock(&q->blk_trace_mutex); 595 ret = __blk_trace_setup(q, name, dev, bdev, arg); 596 mutex_unlock(&q->blk_trace_mutex); 597 598 return ret; 599 } 600 EXPORT_SYMBOL_GPL(blk_trace_setup); 601 602 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 603 static int compat_blk_trace_setup(struct request_queue *q, char *name, 604 dev_t dev, struct block_device *bdev, 605 char __user *arg) 606 { 607 struct blk_user_trace_setup buts; 608 struct compat_blk_user_trace_setup cbuts; 609 int ret; 610 611 if (copy_from_user(&cbuts, arg, sizeof(cbuts))) 612 return -EFAULT; 613 614 buts = (struct blk_user_trace_setup) { 615 .act_mask = cbuts.act_mask, 616 .buf_size = cbuts.buf_size, 617 .buf_nr = cbuts.buf_nr, 618 .start_lba = cbuts.start_lba, 619 .end_lba = cbuts.end_lba, 620 .pid = cbuts.pid, 621 }; 622 623 ret = do_blk_trace_setup(q, name, dev, bdev, &buts); 624 if (ret) 625 return ret; 626 627 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) { 628 __blk_trace_remove(q); 629 return -EFAULT; 630 } 631 632 return 0; 633 } 634 #endif 635 636 static int __blk_trace_startstop(struct request_queue *q, int start) 637 { 638 int ret; 639 struct blk_trace *bt = q->blk_trace; 640 641 if (bt == NULL) 642 return -EINVAL; 643 644 /* 645 * For starting a trace, we can transition from a setup or stopped 646 * trace. For stopping a trace, the state must be running 647 */ 648 ret = -EINVAL; 649 if (start) { 650 if (bt->trace_state == Blktrace_setup || 651 bt->trace_state == Blktrace_stopped) { 652 blktrace_seq++; 653 smp_mb(); 654 bt->trace_state = Blktrace_running; 655 spin_lock_irq(&running_trace_lock); 656 list_add(&bt->running_list, &running_trace_list); 657 spin_unlock_irq(&running_trace_lock); 658 659 trace_note_time(bt); 660 ret = 0; 661 } 662 } else { 663 if (bt->trace_state == Blktrace_running) { 664 bt->trace_state = Blktrace_stopped; 665 spin_lock_irq(&running_trace_lock); 666 list_del_init(&bt->running_list); 667 spin_unlock_irq(&running_trace_lock); 668 relay_flush(bt->rchan); 669 ret = 0; 670 } 671 } 672 673 return ret; 674 } 675 676 int blk_trace_startstop(struct request_queue *q, int start) 677 { 678 int ret; 679 680 mutex_lock(&q->blk_trace_mutex); 681 ret = __blk_trace_startstop(q, start); 682 mutex_unlock(&q->blk_trace_mutex); 683 684 return ret; 685 } 686 EXPORT_SYMBOL_GPL(blk_trace_startstop); 687 688 /* 689 * When reading or writing the blktrace sysfs files, the references to the 690 * opened sysfs or device files should prevent the underlying block device 691 * from being removed. So no further delete protection is really needed. 692 */ 693 694 /** 695 * blk_trace_ioctl: - handle the ioctls associated with tracing 696 * @bdev: the block device 697 * @cmd: the ioctl cmd 698 * @arg: the argument data, if any 699 * 700 **/ 701 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 702 { 703 struct request_queue *q; 704 int ret, start = 0; 705 char b[BDEVNAME_SIZE]; 706 707 q = bdev_get_queue(bdev); 708 if (!q) 709 return -ENXIO; 710 711 mutex_lock(&q->blk_trace_mutex); 712 713 switch (cmd) { 714 case BLKTRACESETUP: 715 bdevname(bdev, b); 716 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 717 break; 718 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64) 719 case BLKTRACESETUP32: 720 bdevname(bdev, b); 721 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg); 722 break; 723 #endif 724 case BLKTRACESTART: 725 start = 1; 726 /* fall through */ 727 case BLKTRACESTOP: 728 ret = __blk_trace_startstop(q, start); 729 break; 730 case BLKTRACETEARDOWN: 731 ret = __blk_trace_remove(q); 732 break; 733 default: 734 ret = -ENOTTY; 735 break; 736 } 737 738 mutex_unlock(&q->blk_trace_mutex); 739 return ret; 740 } 741 742 /** 743 * blk_trace_shutdown: - stop and cleanup trace structures 744 * @q: the request queue associated with the device 745 * 746 **/ 747 void blk_trace_shutdown(struct request_queue *q) 748 { 749 mutex_lock(&q->blk_trace_mutex); 750 751 if (q->blk_trace) { 752 __blk_trace_startstop(q, 0); 753 __blk_trace_remove(q); 754 } 755 756 mutex_unlock(&q->blk_trace_mutex); 757 } 758 759 #ifdef CONFIG_BLK_CGROUP 760 static union kernfs_node_id * 761 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) 762 { 763 struct blk_trace *bt = q->blk_trace; 764 765 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP)) 766 return NULL; 767 768 if (!bio->bi_blkg) 769 return NULL; 770 return cgroup_get_kernfs_id(bio_blkcg(bio)->css.cgroup); 771 } 772 #else 773 static union kernfs_node_id * 774 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) 775 { 776 return NULL; 777 } 778 #endif 779 780 static union kernfs_node_id * 781 blk_trace_request_get_cgid(struct request_queue *q, struct request *rq) 782 { 783 if (!rq->bio) 784 return NULL; 785 /* Use the first bio */ 786 return blk_trace_bio_get_cgid(q, rq->bio); 787 } 788 789 /* 790 * blktrace probes 791 */ 792 793 /** 794 * blk_add_trace_rq - Add a trace for a request oriented action 795 * @rq: the source request 796 * @error: return status to log 797 * @nr_bytes: number of completed bytes 798 * @what: the action 799 * @cgid: the cgroup info 800 * 801 * Description: 802 * Records an action against a request. Will log the bio offset + size. 803 * 804 **/ 805 static void blk_add_trace_rq(struct request *rq, int error, 806 unsigned int nr_bytes, u32 what, 807 union kernfs_node_id *cgid) 808 { 809 struct blk_trace *bt = rq->q->blk_trace; 810 811 if (likely(!bt)) 812 return; 813 814 if (blk_rq_is_passthrough(rq)) 815 what |= BLK_TC_ACT(BLK_TC_PC); 816 else 817 what |= BLK_TC_ACT(BLK_TC_FS); 818 819 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq), 820 rq->cmd_flags, what, error, 0, NULL, cgid); 821 } 822 823 static void blk_add_trace_rq_insert(void *ignore, 824 struct request_queue *q, struct request *rq) 825 { 826 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT, 827 blk_trace_request_get_cgid(q, rq)); 828 } 829 830 static void blk_add_trace_rq_issue(void *ignore, 831 struct request_queue *q, struct request *rq) 832 { 833 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE, 834 blk_trace_request_get_cgid(q, rq)); 835 } 836 837 static void blk_add_trace_rq_requeue(void *ignore, 838 struct request_queue *q, 839 struct request *rq) 840 { 841 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE, 842 blk_trace_request_get_cgid(q, rq)); 843 } 844 845 static void blk_add_trace_rq_complete(void *ignore, struct request *rq, 846 int error, unsigned int nr_bytes) 847 { 848 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE, 849 blk_trace_request_get_cgid(rq->q, rq)); 850 } 851 852 /** 853 * blk_add_trace_bio - Add a trace for a bio oriented action 854 * @q: queue the io is for 855 * @bio: the source bio 856 * @what: the action 857 * @error: error, if any 858 * 859 * Description: 860 * Records an action against a bio. Will log the bio offset + size. 861 * 862 **/ 863 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, 864 u32 what, int error) 865 { 866 struct blk_trace *bt = q->blk_trace; 867 868 if (likely(!bt)) 869 return; 870 871 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 872 bio_op(bio), bio->bi_opf, what, error, 0, NULL, 873 blk_trace_bio_get_cgid(q, bio)); 874 } 875 876 static void blk_add_trace_bio_bounce(void *ignore, 877 struct request_queue *q, struct bio *bio) 878 { 879 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0); 880 } 881 882 static void blk_add_trace_bio_complete(void *ignore, 883 struct request_queue *q, struct bio *bio, 884 int error) 885 { 886 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error); 887 } 888 889 static void blk_add_trace_bio_backmerge(void *ignore, 890 struct request_queue *q, 891 struct request *rq, 892 struct bio *bio) 893 { 894 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0); 895 } 896 897 static void blk_add_trace_bio_frontmerge(void *ignore, 898 struct request_queue *q, 899 struct request *rq, 900 struct bio *bio) 901 { 902 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0); 903 } 904 905 static void blk_add_trace_bio_queue(void *ignore, 906 struct request_queue *q, struct bio *bio) 907 { 908 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0); 909 } 910 911 static void blk_add_trace_getrq(void *ignore, 912 struct request_queue *q, 913 struct bio *bio, int rw) 914 { 915 if (bio) 916 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0); 917 else { 918 struct blk_trace *bt = q->blk_trace; 919 920 if (bt) 921 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0, 922 NULL, NULL); 923 } 924 } 925 926 927 static void blk_add_trace_sleeprq(void *ignore, 928 struct request_queue *q, 929 struct bio *bio, int rw) 930 { 931 if (bio) 932 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0); 933 else { 934 struct blk_trace *bt = q->blk_trace; 935 936 if (bt) 937 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ, 938 0, 0, NULL, NULL); 939 } 940 } 941 942 static void blk_add_trace_plug(void *ignore, struct request_queue *q) 943 { 944 struct blk_trace *bt = q->blk_trace; 945 946 if (bt) 947 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, NULL); 948 } 949 950 static void blk_add_trace_unplug(void *ignore, struct request_queue *q, 951 unsigned int depth, bool explicit) 952 { 953 struct blk_trace *bt = q->blk_trace; 954 955 if (bt) { 956 __be64 rpdu = cpu_to_be64(depth); 957 u32 what; 958 959 if (explicit) 960 what = BLK_TA_UNPLUG_IO; 961 else 962 what = BLK_TA_UNPLUG_TIMER; 963 964 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, NULL); 965 } 966 } 967 968 static void blk_add_trace_split(void *ignore, 969 struct request_queue *q, struct bio *bio, 970 unsigned int pdu) 971 { 972 struct blk_trace *bt = q->blk_trace; 973 974 if (bt) { 975 __be64 rpdu = cpu_to_be64(pdu); 976 977 __blk_add_trace(bt, bio->bi_iter.bi_sector, 978 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf, 979 BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu), 980 &rpdu, blk_trace_bio_get_cgid(q, bio)); 981 } 982 } 983 984 /** 985 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation 986 * @ignore: trace callback data parameter (not used) 987 * @q: queue the io is for 988 * @bio: the source bio 989 * @dev: target device 990 * @from: source sector 991 * 992 * Description: 993 * Device mapper or raid target sometimes need to split a bio because 994 * it spans a stripe (or similar). Add a trace for that action. 995 * 996 **/ 997 static void blk_add_trace_bio_remap(void *ignore, 998 struct request_queue *q, struct bio *bio, 999 dev_t dev, sector_t from) 1000 { 1001 struct blk_trace *bt = q->blk_trace; 1002 struct blk_io_trace_remap r; 1003 1004 if (likely(!bt)) 1005 return; 1006 1007 r.device_from = cpu_to_be32(dev); 1008 r.device_to = cpu_to_be32(bio_dev(bio)); 1009 r.sector_from = cpu_to_be64(from); 1010 1011 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, 1012 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status, 1013 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio)); 1014 } 1015 1016 /** 1017 * blk_add_trace_rq_remap - Add a trace for a request-remap operation 1018 * @ignore: trace callback data parameter (not used) 1019 * @q: queue the io is for 1020 * @rq: the source request 1021 * @dev: target device 1022 * @from: source sector 1023 * 1024 * Description: 1025 * Device mapper remaps request to other devices. 1026 * Add a trace for that action. 1027 * 1028 **/ 1029 static void blk_add_trace_rq_remap(void *ignore, 1030 struct request_queue *q, 1031 struct request *rq, dev_t dev, 1032 sector_t from) 1033 { 1034 struct blk_trace *bt = q->blk_trace; 1035 struct blk_io_trace_remap r; 1036 1037 if (likely(!bt)) 1038 return; 1039 1040 r.device_from = cpu_to_be32(dev); 1041 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk)); 1042 r.sector_from = cpu_to_be64(from); 1043 1044 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 1045 rq_data_dir(rq), 0, BLK_TA_REMAP, 0, 1046 sizeof(r), &r, blk_trace_request_get_cgid(q, rq)); 1047 } 1048 1049 /** 1050 * blk_add_driver_data - Add binary message with driver-specific data 1051 * @q: queue the io is for 1052 * @rq: io request 1053 * @data: driver-specific data 1054 * @len: length of driver-specific data 1055 * 1056 * Description: 1057 * Some drivers might want to write driver-specific data per request. 1058 * 1059 **/ 1060 void blk_add_driver_data(struct request_queue *q, 1061 struct request *rq, 1062 void *data, size_t len) 1063 { 1064 struct blk_trace *bt = q->blk_trace; 1065 1066 if (likely(!bt)) 1067 return; 1068 1069 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0, 1070 BLK_TA_DRV_DATA, 0, len, data, 1071 blk_trace_request_get_cgid(q, rq)); 1072 } 1073 EXPORT_SYMBOL_GPL(blk_add_driver_data); 1074 1075 static void blk_register_tracepoints(void) 1076 { 1077 int ret; 1078 1079 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1080 WARN_ON(ret); 1081 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1082 WARN_ON(ret); 1083 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1084 WARN_ON(ret); 1085 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1086 WARN_ON(ret); 1087 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1088 WARN_ON(ret); 1089 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1090 WARN_ON(ret); 1091 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1092 WARN_ON(ret); 1093 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1094 WARN_ON(ret); 1095 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1096 WARN_ON(ret); 1097 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL); 1098 WARN_ON(ret); 1099 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1100 WARN_ON(ret); 1101 ret = register_trace_block_plug(blk_add_trace_plug, NULL); 1102 WARN_ON(ret); 1103 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL); 1104 WARN_ON(ret); 1105 ret = register_trace_block_split(blk_add_trace_split, NULL); 1106 WARN_ON(ret); 1107 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1108 WARN_ON(ret); 1109 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1110 WARN_ON(ret); 1111 } 1112 1113 static void blk_unregister_tracepoints(void) 1114 { 1115 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); 1116 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); 1117 unregister_trace_block_split(blk_add_trace_split, NULL); 1118 unregister_trace_block_unplug(blk_add_trace_unplug, NULL); 1119 unregister_trace_block_plug(blk_add_trace_plug, NULL); 1120 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); 1121 unregister_trace_block_getrq(blk_add_trace_getrq, NULL); 1122 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL); 1123 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL); 1124 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL); 1125 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); 1126 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL); 1127 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); 1128 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL); 1129 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL); 1130 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL); 1131 1132 tracepoint_synchronize_unregister(); 1133 } 1134 1135 /* 1136 * struct blk_io_tracer formatting routines 1137 */ 1138 1139 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 1140 { 1141 int i = 0; 1142 int tc = t->action >> BLK_TC_SHIFT; 1143 1144 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { 1145 rwbs[i++] = 'N'; 1146 goto out; 1147 } 1148 1149 if (tc & BLK_TC_FLUSH) 1150 rwbs[i++] = 'F'; 1151 1152 if (tc & BLK_TC_DISCARD) 1153 rwbs[i++] = 'D'; 1154 else if (tc & BLK_TC_WRITE) 1155 rwbs[i++] = 'W'; 1156 else if (t->bytes) 1157 rwbs[i++] = 'R'; 1158 else 1159 rwbs[i++] = 'N'; 1160 1161 if (tc & BLK_TC_FUA) 1162 rwbs[i++] = 'F'; 1163 if (tc & BLK_TC_AHEAD) 1164 rwbs[i++] = 'A'; 1165 if (tc & BLK_TC_SYNC) 1166 rwbs[i++] = 'S'; 1167 if (tc & BLK_TC_META) 1168 rwbs[i++] = 'M'; 1169 out: 1170 rwbs[i] = '\0'; 1171 } 1172 1173 static inline 1174 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) 1175 { 1176 return (const struct blk_io_trace *)ent; 1177 } 1178 1179 static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg) 1180 { 1181 return (void *)(te_blk_io_trace(ent) + 1) + 1182 (has_cg ? sizeof(union kernfs_node_id) : 0); 1183 } 1184 1185 static inline const void *cgid_start(const struct trace_entry *ent) 1186 { 1187 return (void *)(te_blk_io_trace(ent) + 1); 1188 } 1189 1190 static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg) 1191 { 1192 return te_blk_io_trace(ent)->pdu_len - 1193 (has_cg ? sizeof(union kernfs_node_id) : 0); 1194 } 1195 1196 static inline u32 t_action(const struct trace_entry *ent) 1197 { 1198 return te_blk_io_trace(ent)->action; 1199 } 1200 1201 static inline u32 t_bytes(const struct trace_entry *ent) 1202 { 1203 return te_blk_io_trace(ent)->bytes; 1204 } 1205 1206 static inline u32 t_sec(const struct trace_entry *ent) 1207 { 1208 return te_blk_io_trace(ent)->bytes >> 9; 1209 } 1210 1211 static inline unsigned long long t_sector(const struct trace_entry *ent) 1212 { 1213 return te_blk_io_trace(ent)->sector; 1214 } 1215 1216 static inline __u16 t_error(const struct trace_entry *ent) 1217 { 1218 return te_blk_io_trace(ent)->error; 1219 } 1220 1221 static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg) 1222 { 1223 const __u64 *val = pdu_start(ent, has_cg); 1224 return be64_to_cpu(*val); 1225 } 1226 1227 static void get_pdu_remap(const struct trace_entry *ent, 1228 struct blk_io_trace_remap *r, bool has_cg) 1229 { 1230 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg); 1231 __u64 sector_from = __r->sector_from; 1232 1233 r->device_from = be32_to_cpu(__r->device_from); 1234 r->device_to = be32_to_cpu(__r->device_to); 1235 r->sector_from = be64_to_cpu(sector_from); 1236 } 1237 1238 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act, 1239 bool has_cg); 1240 1241 static void blk_log_action_classic(struct trace_iterator *iter, const char *act, 1242 bool has_cg) 1243 { 1244 char rwbs[RWBS_LEN]; 1245 unsigned long long ts = iter->ts; 1246 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC); 1247 unsigned secs = (unsigned long)ts; 1248 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1249 1250 fill_rwbs(rwbs, t); 1251 1252 trace_seq_printf(&iter->seq, 1253 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ", 1254 MAJOR(t->device), MINOR(t->device), iter->cpu, 1255 secs, nsec_rem, iter->ent->pid, act, rwbs); 1256 } 1257 1258 static void blk_log_action(struct trace_iterator *iter, const char *act, 1259 bool has_cg) 1260 { 1261 char rwbs[RWBS_LEN]; 1262 const struct blk_io_trace *t = te_blk_io_trace(iter->ent); 1263 1264 fill_rwbs(rwbs, t); 1265 if (has_cg) { 1266 const union kernfs_node_id *id = cgid_start(iter->ent); 1267 1268 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) { 1269 char blkcg_name_buf[NAME_MAX + 1] = "<...>"; 1270 1271 cgroup_path_from_kernfs_id(id, blkcg_name_buf, 1272 sizeof(blkcg_name_buf)); 1273 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ", 1274 MAJOR(t->device), MINOR(t->device), 1275 blkcg_name_buf, act, rwbs); 1276 } else 1277 trace_seq_printf(&iter->seq, 1278 "%3d,%-3d %x,%-x %2s %3s ", 1279 MAJOR(t->device), MINOR(t->device), 1280 id->ino, id->generation, act, rwbs); 1281 } else 1282 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", 1283 MAJOR(t->device), MINOR(t->device), act, rwbs); 1284 } 1285 1286 static void blk_log_dump_pdu(struct trace_seq *s, 1287 const struct trace_entry *ent, bool has_cg) 1288 { 1289 const unsigned char *pdu_buf; 1290 int pdu_len; 1291 int i, end; 1292 1293 pdu_buf = pdu_start(ent, has_cg); 1294 pdu_len = pdu_real_len(ent, has_cg); 1295 1296 if (!pdu_len) 1297 return; 1298 1299 /* find the last zero that needs to be printed */ 1300 for (end = pdu_len - 1; end >= 0; end--) 1301 if (pdu_buf[end]) 1302 break; 1303 end++; 1304 1305 trace_seq_putc(s, '('); 1306 1307 for (i = 0; i < pdu_len; i++) { 1308 1309 trace_seq_printf(s, "%s%02x", 1310 i == 0 ? "" : " ", pdu_buf[i]); 1311 1312 /* 1313 * stop when the rest is just zeroes and indicate so 1314 * with a ".." appended 1315 */ 1316 if (i == end && end != pdu_len - 1) { 1317 trace_seq_puts(s, " ..) "); 1318 return; 1319 } 1320 } 1321 1322 trace_seq_puts(s, ") "); 1323 } 1324 1325 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1326 { 1327 char cmd[TASK_COMM_LEN]; 1328 1329 trace_find_cmdline(ent->pid, cmd); 1330 1331 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1332 trace_seq_printf(s, "%u ", t_bytes(ent)); 1333 blk_log_dump_pdu(s, ent, has_cg); 1334 trace_seq_printf(s, "[%s]\n", cmd); 1335 } else { 1336 if (t_sec(ent)) 1337 trace_seq_printf(s, "%llu + %u [%s]\n", 1338 t_sector(ent), t_sec(ent), cmd); 1339 else 1340 trace_seq_printf(s, "[%s]\n", cmd); 1341 } 1342 } 1343 1344 static void blk_log_with_error(struct trace_seq *s, 1345 const struct trace_entry *ent, bool has_cg) 1346 { 1347 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { 1348 blk_log_dump_pdu(s, ent, has_cg); 1349 trace_seq_printf(s, "[%d]\n", t_error(ent)); 1350 } else { 1351 if (t_sec(ent)) 1352 trace_seq_printf(s, "%llu + %u [%d]\n", 1353 t_sector(ent), 1354 t_sec(ent), t_error(ent)); 1355 else 1356 trace_seq_printf(s, "%llu [%d]\n", 1357 t_sector(ent), t_error(ent)); 1358 } 1359 } 1360 1361 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1362 { 1363 struct blk_io_trace_remap r = { .device_from = 0, }; 1364 1365 get_pdu_remap(ent, &r, has_cg); 1366 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", 1367 t_sector(ent), t_sec(ent), 1368 MAJOR(r.device_from), MINOR(r.device_from), 1369 (unsigned long long)r.sector_from); 1370 } 1371 1372 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1373 { 1374 char cmd[TASK_COMM_LEN]; 1375 1376 trace_find_cmdline(ent->pid, cmd); 1377 1378 trace_seq_printf(s, "[%s]\n", cmd); 1379 } 1380 1381 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1382 { 1383 char cmd[TASK_COMM_LEN]; 1384 1385 trace_find_cmdline(ent->pid, cmd); 1386 1387 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg)); 1388 } 1389 1390 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) 1391 { 1392 char cmd[TASK_COMM_LEN]; 1393 1394 trace_find_cmdline(ent->pid, cmd); 1395 1396 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), 1397 get_pdu_int(ent, has_cg), cmd); 1398 } 1399 1400 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent, 1401 bool has_cg) 1402 { 1403 1404 trace_seq_putmem(s, pdu_start(ent, has_cg), 1405 pdu_real_len(ent, has_cg)); 1406 trace_seq_putc(s, '\n'); 1407 } 1408 1409 /* 1410 * struct tracer operations 1411 */ 1412 1413 static void blk_tracer_print_header(struct seq_file *m) 1414 { 1415 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1416 return; 1417 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" 1418 "# | | | | | |\n"); 1419 } 1420 1421 static void blk_tracer_start(struct trace_array *tr) 1422 { 1423 blk_tracer_enabled = true; 1424 } 1425 1426 static int blk_tracer_init(struct trace_array *tr) 1427 { 1428 blk_tr = tr; 1429 blk_tracer_start(tr); 1430 return 0; 1431 } 1432 1433 static void blk_tracer_stop(struct trace_array *tr) 1434 { 1435 blk_tracer_enabled = false; 1436 } 1437 1438 static void blk_tracer_reset(struct trace_array *tr) 1439 { 1440 blk_tracer_stop(tr); 1441 } 1442 1443 static const struct { 1444 const char *act[2]; 1445 void (*print)(struct trace_seq *s, const struct trace_entry *ent, 1446 bool has_cg); 1447 } what2act[] = { 1448 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, 1449 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, 1450 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, 1451 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, 1452 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, 1453 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, 1454 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, 1455 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, 1456 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, 1457 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, 1458 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, 1459 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, 1460 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, 1461 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, 1462 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, 1463 }; 1464 1465 static enum print_line_t print_one_line(struct trace_iterator *iter, 1466 bool classic) 1467 { 1468 struct trace_array *tr = iter->tr; 1469 struct trace_seq *s = &iter->seq; 1470 const struct blk_io_trace *t; 1471 u16 what; 1472 bool long_act; 1473 blk_log_action_t *log_action; 1474 bool has_cg; 1475 1476 t = te_blk_io_trace(iter->ent); 1477 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP; 1478 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE); 1479 log_action = classic ? &blk_log_action_classic : &blk_log_action; 1480 has_cg = t->action & __BLK_TA_CGROUP; 1481 1482 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { 1483 log_action(iter, long_act ? "message" : "m", has_cg); 1484 blk_log_msg(s, iter->ent, has_cg); 1485 return trace_handle_return(s); 1486 } 1487 1488 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) 1489 trace_seq_printf(s, "Unknown action %x\n", what); 1490 else { 1491 log_action(iter, what2act[what].act[long_act], has_cg); 1492 what2act[what].print(s, iter->ent, has_cg); 1493 } 1494 1495 return trace_handle_return(s); 1496 } 1497 1498 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, 1499 int flags, struct trace_event *event) 1500 { 1501 return print_one_line(iter, false); 1502 } 1503 1504 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter) 1505 { 1506 struct trace_seq *s = &iter->seq; 1507 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; 1508 const int offset = offsetof(struct blk_io_trace, sector); 1509 struct blk_io_trace old = { 1510 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, 1511 .time = iter->ts, 1512 }; 1513 1514 trace_seq_putmem(s, &old, offset); 1515 trace_seq_putmem(s, &t->sector, 1516 sizeof(old) - offset + t->pdu_len); 1517 } 1518 1519 static enum print_line_t 1520 blk_trace_event_print_binary(struct trace_iterator *iter, int flags, 1521 struct trace_event *event) 1522 { 1523 blk_trace_synthesize_old_trace(iter); 1524 1525 return trace_handle_return(&iter->seq); 1526 } 1527 1528 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) 1529 { 1530 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) 1531 return TRACE_TYPE_UNHANDLED; 1532 1533 return print_one_line(iter, true); 1534 } 1535 1536 static int 1537 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) 1538 { 1539 /* don't output context-info for blk_classic output */ 1540 if (bit == TRACE_BLK_OPT_CLASSIC) { 1541 if (set) 1542 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO; 1543 else 1544 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO; 1545 } 1546 return 0; 1547 } 1548 1549 static struct tracer blk_tracer __read_mostly = { 1550 .name = "blk", 1551 .init = blk_tracer_init, 1552 .reset = blk_tracer_reset, 1553 .start = blk_tracer_start, 1554 .stop = blk_tracer_stop, 1555 .print_header = blk_tracer_print_header, 1556 .print_line = blk_tracer_print_line, 1557 .flags = &blk_tracer_flags, 1558 .set_flag = blk_tracer_set_flag, 1559 }; 1560 1561 static struct trace_event_functions trace_blk_event_funcs = { 1562 .trace = blk_trace_event_print, 1563 .binary = blk_trace_event_print_binary, 1564 }; 1565 1566 static struct trace_event trace_blk_event = { 1567 .type = TRACE_BLK, 1568 .funcs = &trace_blk_event_funcs, 1569 }; 1570 1571 static int __init init_blk_tracer(void) 1572 { 1573 if (!register_trace_event(&trace_blk_event)) { 1574 pr_warn("Warning: could not register block events\n"); 1575 return 1; 1576 } 1577 1578 if (register_tracer(&blk_tracer) != 0) { 1579 pr_warn("Warning: could not register the block tracer\n"); 1580 unregister_trace_event(&trace_blk_event); 1581 return 1; 1582 } 1583 1584 return 0; 1585 } 1586 1587 device_initcall(init_blk_tracer); 1588 1589 static int blk_trace_remove_queue(struct request_queue *q) 1590 { 1591 struct blk_trace *bt; 1592 1593 bt = xchg(&q->blk_trace, NULL); 1594 if (bt == NULL) 1595 return -EINVAL; 1596 1597 put_probe_ref(); 1598 blk_trace_free(bt); 1599 return 0; 1600 } 1601 1602 /* 1603 * Setup everything required to start tracing 1604 */ 1605 static int blk_trace_setup_queue(struct request_queue *q, 1606 struct block_device *bdev) 1607 { 1608 struct blk_trace *bt = NULL; 1609 int ret = -ENOMEM; 1610 1611 bt = kzalloc(sizeof(*bt), GFP_KERNEL); 1612 if (!bt) 1613 return -ENOMEM; 1614 1615 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); 1616 if (!bt->msg_data) 1617 goto free_bt; 1618 1619 bt->dev = bdev->bd_dev; 1620 bt->act_mask = (u16)-1; 1621 1622 blk_trace_setup_lba(bt, bdev); 1623 1624 ret = -EBUSY; 1625 if (cmpxchg(&q->blk_trace, NULL, bt)) 1626 goto free_bt; 1627 1628 get_probe_ref(); 1629 return 0; 1630 1631 free_bt: 1632 blk_trace_free(bt); 1633 return ret; 1634 } 1635 1636 /* 1637 * sysfs interface to enable and configure tracing 1638 */ 1639 1640 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1641 struct device_attribute *attr, 1642 char *buf); 1643 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1644 struct device_attribute *attr, 1645 const char *buf, size_t count); 1646 #define BLK_TRACE_DEVICE_ATTR(_name) \ 1647 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ 1648 sysfs_blk_trace_attr_show, \ 1649 sysfs_blk_trace_attr_store) 1650 1651 static BLK_TRACE_DEVICE_ATTR(enable); 1652 static BLK_TRACE_DEVICE_ATTR(act_mask); 1653 static BLK_TRACE_DEVICE_ATTR(pid); 1654 static BLK_TRACE_DEVICE_ATTR(start_lba); 1655 static BLK_TRACE_DEVICE_ATTR(end_lba); 1656 1657 static struct attribute *blk_trace_attrs[] = { 1658 &dev_attr_enable.attr, 1659 &dev_attr_act_mask.attr, 1660 &dev_attr_pid.attr, 1661 &dev_attr_start_lba.attr, 1662 &dev_attr_end_lba.attr, 1663 NULL 1664 }; 1665 1666 struct attribute_group blk_trace_attr_group = { 1667 .name = "trace", 1668 .attrs = blk_trace_attrs, 1669 }; 1670 1671 static const struct { 1672 int mask; 1673 const char *str; 1674 } mask_maps[] = { 1675 { BLK_TC_READ, "read" }, 1676 { BLK_TC_WRITE, "write" }, 1677 { BLK_TC_FLUSH, "flush" }, 1678 { BLK_TC_SYNC, "sync" }, 1679 { BLK_TC_QUEUE, "queue" }, 1680 { BLK_TC_REQUEUE, "requeue" }, 1681 { BLK_TC_ISSUE, "issue" }, 1682 { BLK_TC_COMPLETE, "complete" }, 1683 { BLK_TC_FS, "fs" }, 1684 { BLK_TC_PC, "pc" }, 1685 { BLK_TC_NOTIFY, "notify" }, 1686 { BLK_TC_AHEAD, "ahead" }, 1687 { BLK_TC_META, "meta" }, 1688 { BLK_TC_DISCARD, "discard" }, 1689 { BLK_TC_DRV_DATA, "drv_data" }, 1690 { BLK_TC_FUA, "fua" }, 1691 }; 1692 1693 static int blk_trace_str2mask(const char *str) 1694 { 1695 int i; 1696 int mask = 0; 1697 char *buf, *s, *token; 1698 1699 buf = kstrdup(str, GFP_KERNEL); 1700 if (buf == NULL) 1701 return -ENOMEM; 1702 s = strstrip(buf); 1703 1704 while (1) { 1705 token = strsep(&s, ","); 1706 if (token == NULL) 1707 break; 1708 1709 if (*token == '\0') 1710 continue; 1711 1712 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1713 if (strcasecmp(token, mask_maps[i].str) == 0) { 1714 mask |= mask_maps[i].mask; 1715 break; 1716 } 1717 } 1718 if (i == ARRAY_SIZE(mask_maps)) { 1719 mask = -EINVAL; 1720 break; 1721 } 1722 } 1723 kfree(buf); 1724 1725 return mask; 1726 } 1727 1728 static ssize_t blk_trace_mask2str(char *buf, int mask) 1729 { 1730 int i; 1731 char *p = buf; 1732 1733 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) { 1734 if (mask & mask_maps[i].mask) { 1735 p += sprintf(p, "%s%s", 1736 (p == buf) ? "" : ",", mask_maps[i].str); 1737 } 1738 } 1739 *p++ = '\n'; 1740 1741 return p - buf; 1742 } 1743 1744 static struct request_queue *blk_trace_get_queue(struct block_device *bdev) 1745 { 1746 if (bdev->bd_disk == NULL) 1747 return NULL; 1748 1749 return bdev_get_queue(bdev); 1750 } 1751 1752 static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 1753 struct device_attribute *attr, 1754 char *buf) 1755 { 1756 struct hd_struct *p = dev_to_part(dev); 1757 struct request_queue *q; 1758 struct block_device *bdev; 1759 ssize_t ret = -ENXIO; 1760 1761 bdev = bdget(part_devt(p)); 1762 if (bdev == NULL) 1763 goto out; 1764 1765 q = blk_trace_get_queue(bdev); 1766 if (q == NULL) 1767 goto out_bdput; 1768 1769 mutex_lock(&q->blk_trace_mutex); 1770 1771 if (attr == &dev_attr_enable) { 1772 ret = sprintf(buf, "%u\n", !!q->blk_trace); 1773 goto out_unlock_bdev; 1774 } 1775 1776 if (q->blk_trace == NULL) 1777 ret = sprintf(buf, "disabled\n"); 1778 else if (attr == &dev_attr_act_mask) 1779 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask); 1780 else if (attr == &dev_attr_pid) 1781 ret = sprintf(buf, "%u\n", q->blk_trace->pid); 1782 else if (attr == &dev_attr_start_lba) 1783 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); 1784 else if (attr == &dev_attr_end_lba) 1785 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); 1786 1787 out_unlock_bdev: 1788 mutex_unlock(&q->blk_trace_mutex); 1789 out_bdput: 1790 bdput(bdev); 1791 out: 1792 return ret; 1793 } 1794 1795 static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 1796 struct device_attribute *attr, 1797 const char *buf, size_t count) 1798 { 1799 struct block_device *bdev; 1800 struct request_queue *q; 1801 struct hd_struct *p; 1802 u64 value; 1803 ssize_t ret = -EINVAL; 1804 1805 if (count == 0) 1806 goto out; 1807 1808 if (attr == &dev_attr_act_mask) { 1809 if (kstrtoull(buf, 0, &value)) { 1810 /* Assume it is a list of trace category names */ 1811 ret = blk_trace_str2mask(buf); 1812 if (ret < 0) 1813 goto out; 1814 value = ret; 1815 } 1816 } else if (kstrtoull(buf, 0, &value)) 1817 goto out; 1818 1819 ret = -ENXIO; 1820 1821 p = dev_to_part(dev); 1822 bdev = bdget(part_devt(p)); 1823 if (bdev == NULL) 1824 goto out; 1825 1826 q = blk_trace_get_queue(bdev); 1827 if (q == NULL) 1828 goto out_bdput; 1829 1830 mutex_lock(&q->blk_trace_mutex); 1831 1832 if (attr == &dev_attr_enable) { 1833 if (!!value == !!q->blk_trace) { 1834 ret = 0; 1835 goto out_unlock_bdev; 1836 } 1837 if (value) 1838 ret = blk_trace_setup_queue(q, bdev); 1839 else 1840 ret = blk_trace_remove_queue(q); 1841 goto out_unlock_bdev; 1842 } 1843 1844 ret = 0; 1845 if (q->blk_trace == NULL) 1846 ret = blk_trace_setup_queue(q, bdev); 1847 1848 if (ret == 0) { 1849 if (attr == &dev_attr_act_mask) 1850 q->blk_trace->act_mask = value; 1851 else if (attr == &dev_attr_pid) 1852 q->blk_trace->pid = value; 1853 else if (attr == &dev_attr_start_lba) 1854 q->blk_trace->start_lba = value; 1855 else if (attr == &dev_attr_end_lba) 1856 q->blk_trace->end_lba = value; 1857 } 1858 1859 out_unlock_bdev: 1860 mutex_unlock(&q->blk_trace_mutex); 1861 out_bdput: 1862 bdput(bdev); 1863 out: 1864 return ret ? ret : count; 1865 } 1866 1867 int blk_trace_init_sysfs(struct device *dev) 1868 { 1869 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group); 1870 } 1871 1872 void blk_trace_remove_sysfs(struct device *dev) 1873 { 1874 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group); 1875 } 1876 1877 #endif /* CONFIG_BLK_DEV_IO_TRACE */ 1878 1879 #ifdef CONFIG_EVENT_TRACING 1880 1881 void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes) 1882 { 1883 int i = 0; 1884 1885 if (op & REQ_PREFLUSH) 1886 rwbs[i++] = 'F'; 1887 1888 switch (op & REQ_OP_MASK) { 1889 case REQ_OP_WRITE: 1890 case REQ_OP_WRITE_SAME: 1891 rwbs[i++] = 'W'; 1892 break; 1893 case REQ_OP_DISCARD: 1894 rwbs[i++] = 'D'; 1895 break; 1896 case REQ_OP_SECURE_ERASE: 1897 rwbs[i++] = 'D'; 1898 rwbs[i++] = 'E'; 1899 break; 1900 case REQ_OP_FLUSH: 1901 rwbs[i++] = 'F'; 1902 break; 1903 case REQ_OP_READ: 1904 rwbs[i++] = 'R'; 1905 break; 1906 default: 1907 rwbs[i++] = 'N'; 1908 } 1909 1910 if (op & REQ_FUA) 1911 rwbs[i++] = 'F'; 1912 if (op & REQ_RAHEAD) 1913 rwbs[i++] = 'A'; 1914 if (op & REQ_SYNC) 1915 rwbs[i++] = 'S'; 1916 if (op & REQ_META) 1917 rwbs[i++] = 'M'; 1918 1919 rwbs[i] = '\0'; 1920 } 1921 EXPORT_SYMBOL_GPL(blk_fill_rwbs); 1922 1923 #endif /* CONFIG_EVENT_TRACING */ 1924 1925