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