1/*
   2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 * GNU General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public License
  14 * along with this program; if not, write to the Free Software
  15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  16 *
  17 */
  18#include <linux/kernel.h>
  19#include <linux/blkdev.h>
  20#include <linux/blktrace_api.h>
  21#include <linux/percpu.h>
  22#include <linux/init.h>
  23#include <linux/mutex.h>
  24#include <linux/slab.h>
  25#include <linux/debugfs.h>
  26#include <linux/export.h>
  27#include <linux/time.h>
  28#include <linux/uaccess.h>
  29#include <linux/list.h>
  30
  31#include <trace/events/block.h>
  32
  33#include "trace_output.h"
  34
  35#ifdef CONFIG_BLK_DEV_IO_TRACE
  36
  37static unsigned int blktrace_seq __read_mostly = 1;
  38
  39static struct trace_array *blk_tr;
  40static bool blk_tracer_enabled __read_mostly;
  41
  42static LIST_HEAD(running_trace_list);
  43static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
  44
  45/* Select an alternative, minimalistic output than the original one */
  46#define TRACE_BLK_OPT_CLASSIC	0x1
  47
  48static struct tracer_opt blk_tracer_opts[] = {
  49	/* Default disable the minimalistic output */
  50	{ TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
  51	{ }
  52};
  53
  54static struct tracer_flags blk_tracer_flags = {
  55	.val  = 0,
  56	.opts = blk_tracer_opts,
  57};
  58
  59/* Global reference count of probes */
  60static atomic_t blk_probes_ref = ATOMIC_INIT(0);
  61
  62static void blk_register_tracepoints(void);
  63static void blk_unregister_tracepoints(void);
  64
  65/*
  66 * Send out a notify message.
  67 */
  68static void trace_note(struct blk_trace *bt, pid_t pid, int action,
  69		       const void *data, size_t len)
  70{
  71	struct blk_io_trace *t;
  72	struct ring_buffer_event *event = NULL;
  73	struct ring_buffer *buffer = NULL;
  74	int pc = 0;
  75	int cpu = smp_processor_id();
  76	bool blk_tracer = blk_tracer_enabled;
  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,
  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);
  94	if (t) {
  95		t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
  96		t->time = ktime_to_ns(ktime_get());
  97record_it:
  98		t->device = bt->dev;
  99		t->action = action;
 100		t->pid = pid;
 101		t->cpu = cpu;
 102		t->pdu_len = len;
 103		memcpy((void *) t + sizeof(*t), data, len);
 104
 105		if (blk_tracer)
 106			trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
 107	}
 108}
 109
 110/*
 111 * Send out a notify for this process, if we haven't done so since a trace
 112 * started
 113 */
 114static void trace_note_tsk(struct task_struct *tsk)
 115{
 116	unsigned long flags;
 117	struct blk_trace *bt;
 118
 119	tsk->btrace_seq = blktrace_seq;
 120	spin_lock_irqsave(&running_trace_lock, flags);
 121	list_for_each_entry(bt, &running_trace_list, running_list) {
 122		trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
 123			   sizeof(tsk->comm));
 124	}
 125	spin_unlock_irqrestore(&running_trace_lock, flags);
 126}
 127
 128static void trace_note_time(struct blk_trace *bt)
 129{
 130	struct timespec64 now;
 131	unsigned long flags;
 132	u32 words[2];
 133
 134	/* need to check user space to see if this breaks in y2038 or y2106 */
 135	ktime_get_real_ts64(&now);
 136	words[0] = (u32)now.tv_sec;
 137	words[1] = now.tv_nsec;
 138
 139	local_irq_save(flags);
 140	trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
 141	local_irq_restore(flags);
 142}
 143
 144void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
 145{
 146	int n;
 147	va_list args;
 148	unsigned long flags;
 149	char *buf;
 150
 151	if (unlikely(bt->trace_state != Blktrace_running &&
 152		     !blk_tracer_enabled))
 153		return;
 154
 155	/*
 156	 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
 157	 * message to the trace.
 158	 */
 159	if (!(bt->act_mask & BLK_TC_NOTIFY))
 160		return;
 161
 162	local_irq_save(flags);
 163	buf = this_cpu_ptr(bt->msg_data);
 164	va_start(args, fmt);
 165	n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
 166	va_end(args);
 167
 168	trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
 169	local_irq_restore(flags);
 170}
 171EXPORT_SYMBOL_GPL(__trace_note_message);
 172
 173static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
 174			 pid_t pid)
 175{
 176	if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
 177		return 1;
 178	if (sector && (sector < bt->start_lba || sector > bt->end_lba))
 179		return 1;
 180	if (bt->pid && pid != bt->pid)
 181		return 1;
 182
 183	return 0;
 184}
 185
 186/*
 187 * Data direction bit lookup
 188 */
 189static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
 190				 BLK_TC_ACT(BLK_TC_WRITE) };
 191
 192#define BLK_TC_RAHEAD		BLK_TC_AHEAD
 193#define BLK_TC_PREFLUSH		BLK_TC_FLUSH
 194
 195/* The ilog2() calls fall out because they're constant */
 196#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
 197	  (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
 198
 199/*
 200 * The worker for the various blk_add_trace*() types. Fills out a
 201 * blk_io_trace structure and places it in a per-cpu subbuffer.
 202 */
 203static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
 204		     int op, int op_flags, u32 what, int error, int pdu_len,
 205		     void *pdu_data)
 206{
 207	struct task_struct *tsk = current;
 208	struct ring_buffer_event *event = NULL;
 209	struct ring_buffer *buffer = NULL;
 210	struct blk_io_trace *t;
 211	unsigned long flags = 0;
 212	unsigned long *sequence;
 213	pid_t pid;
 214	int cpu, pc = 0;
 215	bool blk_tracer = blk_tracer_enabled;
 216
 217	if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
 218		return;
 219
 220	what |= ddir_act[op_is_write(op) ? WRITE : READ];
 221	what |= MASK_TC_BIT(op_flags, SYNC);
 222	what |= MASK_TC_BIT(op_flags, RAHEAD);
 223	what |= MASK_TC_BIT(op_flags, META);
 224	what |= MASK_TC_BIT(op_flags, PREFLUSH);
 225	what |= MASK_TC_BIT(op_flags, FUA);
 226	if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
 227		what |= BLK_TC_ACT(BLK_TC_DISCARD);
 228	if (op == REQ_OP_FLUSH)
 229		what |= BLK_TC_ACT(BLK_TC_FLUSH);
 230
 231	pid = tsk->pid;
 232	if (act_log_check(bt, what, sector, pid))
 233		return;
 234	cpu = raw_smp_processor_id();
 235
 236	if (blk_tracer) {
 237		tracing_record_cmdline(current);
 238
 239		buffer = blk_tr->trace_buffer.buffer;
 240		pc = preempt_count();
 241		event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
 242						  sizeof(*t) + pdu_len,
 243						  0, pc);
 244		if (!event)
 245			return;
 246		t = ring_buffer_event_data(event);
 247		goto record_it;
 248	}
 249
 250	if (unlikely(tsk->btrace_seq != blktrace_seq))
 251		trace_note_tsk(tsk);
 252
 253	/*
 254	 * A word about the locking here - we disable interrupts to reserve
 255	 * some space in the relay per-cpu buffer, to prevent an irq
 256	 * from coming in and stepping on our toes.
 257	 */
 258	local_irq_save(flags);
 259	t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
 260	if (t) {
 261		sequence = per_cpu_ptr(bt->sequence, cpu);
 262
 263		t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
 264		t->sequence = ++(*sequence);
 265		t->time = ktime_to_ns(ktime_get());
 266record_it:
 267		/*
 268		 * These two are not needed in ftrace as they are in the
 269		 * generic trace_entry, filled by tracing_generic_entry_update,
 270		 * but for the trace_event->bin() synthesizer benefit we do it
 271		 * here too.
 272		 */
 273		t->cpu = cpu;
 274		t->pid = pid;
 275
 276		t->sector = sector;
 277		t->bytes = bytes;
 278		t->action = what;
 279		t->device = bt->dev;
 280		t->error = error;
 281		t->pdu_len = pdu_len;
 282
 283		if (pdu_len)
 284			memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
 285
 286		if (blk_tracer) {
 287			trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
 288			return;
 289		}
 290	}
 291
 292	local_irq_restore(flags);
 293}
 294
 295static struct dentry *blk_tree_root;
 296static DEFINE_MUTEX(blk_tree_mutex);
 297
 298static void blk_trace_free(struct blk_trace *bt)
 299{
 300	debugfs_remove(bt->msg_file);
 301	debugfs_remove(bt->dropped_file);
 302	relay_close(bt->rchan);
 303	debugfs_remove(bt->dir);
 304	free_percpu(bt->sequence);
 305	free_percpu(bt->msg_data);
 306	kfree(bt);
 307}
 308
 309static void blk_trace_cleanup(struct blk_trace *bt)
 310{
 311	blk_trace_free(bt);
 312	if (atomic_dec_and_test(&blk_probes_ref))
 313		blk_unregister_tracepoints();
 314}
 315
 316int blk_trace_remove(struct request_queue *q)
 317{
 318	struct blk_trace *bt;
 319
 320	bt = xchg(&q->blk_trace, NULL);
 321	if (!bt)
 322		return -EINVAL;
 323
 324	if (bt->trace_state != Blktrace_running)
 325		blk_trace_cleanup(bt);
 326
 327	return 0;
 328}
 329EXPORT_SYMBOL_GPL(blk_trace_remove);
 330
 331static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
 332				size_t count, loff_t *ppos)
 333{
 334	struct blk_trace *bt = filp->private_data;
 335	char buf[16];
 336
 337	snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
 338
 339	return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
 340}
 341
 342static const struct file_operations blk_dropped_fops = {
 343	.owner =	THIS_MODULE,
 344	.open =		simple_open,
 345	.read =		blk_dropped_read,
 346	.llseek =	default_llseek,
 347};
 348
 349static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
 350				size_t count, loff_t *ppos)
 351{
 352	char *msg;
 353	struct blk_trace *bt;
 354
 355	if (count >= BLK_TN_MAX_MSG)
 356		return -EINVAL;
 357
 358	msg = memdup_user_nul(buffer, count);
 359	if (IS_ERR(msg))
 360		return PTR_ERR(msg);
 361
 362	bt = filp->private_data;
 363	__trace_note_message(bt, "%s", msg);
 364	kfree(msg);
 365
 366	return count;
 367}
 368
 369static const struct file_operations blk_msg_fops = {
 370	.owner =	THIS_MODULE,
 371	.open =		simple_open,
 372	.write =	blk_msg_write,
 373	.llseek =	noop_llseek,
 374};
 375
 376/*
 377 * Keep track of how many times we encountered a full subbuffer, to aid
 378 * the user space app in telling how many lost events there were.
 379 */
 380static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
 381				     void *prev_subbuf, size_t prev_padding)
 382{
 383	struct blk_trace *bt;
 384
 385	if (!relay_buf_full(buf))
 386		return 1;
 387
 388	bt = buf->chan->private_data;
 389	atomic_inc(&bt->dropped);
 390	return 0;
 391}
 392
 393static int blk_remove_buf_file_callback(struct dentry *dentry)
 394{
 395	debugfs_remove(dentry);
 396
 397	return 0;
 398}
 399
 400static struct dentry *blk_create_buf_file_callback(const char *filename,
 401						   struct dentry *parent,
 402						   umode_t mode,
 403						   struct rchan_buf *buf,
 404						   int *is_global)
 405{
 406	return debugfs_create_file(filename, mode, parent, buf,
 407					&relay_file_operations);
 408}
 409
 410static struct rchan_callbacks blk_relay_callbacks = {
 411	.subbuf_start		= blk_subbuf_start_callback,
 412	.create_buf_file	= blk_create_buf_file_callback,
 413	.remove_buf_file	= blk_remove_buf_file_callback,
 414};
 415
 416static void blk_trace_setup_lba(struct blk_trace *bt,
 417				struct block_device *bdev)
 418{
 419	struct hd_struct *part = NULL;
 420
 421	if (bdev)
 422		part = bdev->bd_part;
 423
 424	if (part) {
 425		bt->start_lba = part->start_sect;
 426		bt->end_lba = part->start_sect + part->nr_sects;
 427	} else {
 428		bt->start_lba = 0;
 429		bt->end_lba = -1ULL;
 430	}
 431}
 432
 433/*
 434 * Setup everything required to start tracing
 435 */
 436int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 437		       struct block_device *bdev,
 438		       struct blk_user_trace_setup *buts)
 439{
 440	struct blk_trace *bt = NULL;
 441	struct dentry *dir = NULL;
 442	int ret;
 443
 444	if (!buts->buf_size || !buts->buf_nr)
 445		return -EINVAL;
 446
 447	strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
 448	buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
 449
 450	/*
 451	 * some device names have larger paths - convert the slashes
 452	 * to underscores for this to work as expected
 453	 */
 454	strreplace(buts->name, '/', '_');
 455
 456	bt = kzalloc(sizeof(*bt), GFP_KERNEL);
 457	if (!bt)
 458		return -ENOMEM;
 459
 460	ret = -ENOMEM;
 461	bt->sequence = alloc_percpu(unsigned long);
 462	if (!bt->sequence)
 463		goto err;
 464
 465	bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
 466	if (!bt->msg_data)
 467		goto err;
 468
 469	ret = -ENOENT;
 470
 471	mutex_lock(&blk_tree_mutex);
 472	if (!blk_tree_root) {
 473		blk_tree_root = debugfs_create_dir("block", NULL);
 474		if (!blk_tree_root) {
 475			mutex_unlock(&blk_tree_mutex);
 476			goto err;
 477		}
 478	}
 479	mutex_unlock(&blk_tree_mutex);
 480
 481	dir = debugfs_create_dir(buts->name, blk_tree_root);
 482
 483	if (!dir)
 484		goto err;
 485
 486	bt->dir = dir;
 487	bt->dev = dev;
 488	atomic_set(&bt->dropped, 0);
 489	INIT_LIST_HEAD(&bt->running_list);
 490
 491	ret = -EIO;
 492	bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
 493					       &blk_dropped_fops);
 494	if (!bt->dropped_file)
 495		goto err;
 496
 497	bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
 498	if (!bt->msg_file)
 499		goto err;
 500
 501	bt->rchan = relay_open("trace", dir, buts->buf_size,
 502				buts->buf_nr, &blk_relay_callbacks, bt);
 503	if (!bt->rchan)
 504		goto err;
 505
 506	bt->act_mask = buts->act_mask;
 507	if (!bt->act_mask)
 508		bt->act_mask = (u16) -1;
 509
 510	blk_trace_setup_lba(bt, bdev);
 511
 512	/* overwrite with user settings */
 513	if (buts->start_lba)
 514		bt->start_lba = buts->start_lba;
 515	if (buts->end_lba)
 516		bt->end_lba = buts->end_lba;
 517
 518	bt->pid = buts->pid;
 519	bt->trace_state = Blktrace_setup;
 520
 521	ret = -EBUSY;
 522	if (cmpxchg(&q->blk_trace, NULL, bt))
 523		goto err;
 524
 525	if (atomic_inc_return(&blk_probes_ref) == 1)
 526		blk_register_tracepoints();
 527
 528	return 0;
 529err:
 530	blk_trace_free(bt);
 531	return ret;
 532}
 533
 534int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 535		    struct block_device *bdev,
 536		    char __user *arg)
 537{
 538	struct blk_user_trace_setup buts;
 539	int ret;
 540
 541	ret = copy_from_user(&buts, arg, sizeof(buts));
 542	if (ret)
 543		return -EFAULT;
 544
 545	ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
 546	if (ret)
 547		return ret;
 548
 549	if (copy_to_user(arg, &buts, sizeof(buts))) {
 550		blk_trace_remove(q);
 551		return -EFAULT;
 552	}
 553	return 0;
 554}
 555EXPORT_SYMBOL_GPL(blk_trace_setup);
 556
 557#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
 558static int compat_blk_trace_setup(struct request_queue *q, char *name,
 559				  dev_t dev, struct block_device *bdev,
 560				  char __user *arg)
 561{
 562	struct blk_user_trace_setup buts;
 563	struct compat_blk_user_trace_setup cbuts;
 564	int ret;
 565
 566	if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
 567		return -EFAULT;
 568
 569	buts = (struct blk_user_trace_setup) {
 570		.act_mask = cbuts.act_mask,
 571		.buf_size = cbuts.buf_size,
 572		.buf_nr = cbuts.buf_nr,
 573		.start_lba = cbuts.start_lba,
 574		.end_lba = cbuts.end_lba,
 575		.pid = cbuts.pid,
 576	};
 577
 578	ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
 579	if (ret)
 580		return ret;
 581
 582	if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
 583		blk_trace_remove(q);
 584		return -EFAULT;
 585	}
 586
 587	return 0;
 588}
 589#endif
 590
 591int blk_trace_startstop(struct request_queue *q, int start)
 592{
 593	int ret;
 594	struct blk_trace *bt = q->blk_trace;
 595
 596	if (bt == NULL)
 597		return -EINVAL;
 598
 599	/*
 600	 * For starting a trace, we can transition from a setup or stopped
 601	 * trace. For stopping a trace, the state must be running
 602	 */
 603	ret = -EINVAL;
 604	if (start) {
 605		if (bt->trace_state == Blktrace_setup ||
 606		    bt->trace_state == Blktrace_stopped) {
 607			blktrace_seq++;
 608			smp_mb();
 609			bt->trace_state = Blktrace_running;
 610			spin_lock_irq(&running_trace_lock);
 611			list_add(&bt->running_list, &running_trace_list);
 612			spin_unlock_irq(&running_trace_lock);
 613
 614			trace_note_time(bt);
 615			ret = 0;
 616		}
 617	} else {
 618		if (bt->trace_state == Blktrace_running) {
 619			bt->trace_state = Blktrace_stopped;
 620			spin_lock_irq(&running_trace_lock);
 621			list_del_init(&bt->running_list);
 622			spin_unlock_irq(&running_trace_lock);
 623			relay_flush(bt->rchan);
 624			ret = 0;
 625		}
 626	}
 627
 628	return ret;
 629}
 630EXPORT_SYMBOL_GPL(blk_trace_startstop);
 631
 632/**
 633 * blk_trace_ioctl: - handle the ioctls associated with tracing
 634 * @bdev:	the block device
 635 * @cmd:	the ioctl cmd
 636 * @arg:	the argument data, if any
 637 *
 638 **/
 639int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 640{
 641	struct request_queue *q;
 642	int ret, start = 0;
 643	char b[BDEVNAME_SIZE];
 644
 645	q = bdev_get_queue(bdev);
 646	if (!q)
 647		return -ENXIO;
 648
 649	mutex_lock(&bdev->bd_mutex);
 650
 651	switch (cmd) {
 652	case BLKTRACESETUP:
 653		bdevname(bdev, b);
 654		ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
 655		break;
 656#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
 657	case BLKTRACESETUP32:
 658		bdevname(bdev, b);
 659		ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
 660		break;
 661#endif
 662	case BLKTRACESTART:
 663		start = 1;
 664	case BLKTRACESTOP:
 665		ret = blk_trace_startstop(q, start);
 666		break;
 667	case BLKTRACETEARDOWN:
 668		ret = blk_trace_remove(q);
 669		break;
 670	default:
 671		ret = -ENOTTY;
 672		break;
 673	}
 674
 675	mutex_unlock(&bdev->bd_mutex);
 676	return ret;
 677}
 678
 679/**
 680 * blk_trace_shutdown: - stop and cleanup trace structures
 681 * @q:    the request queue associated with the device
 682 *
 683 **/
 684void blk_trace_shutdown(struct request_queue *q)
 685{
 686	if (q->blk_trace) {
 687		blk_trace_startstop(q, 0);
 688		blk_trace_remove(q);
 689	}
 690}
 691
 692/*
 693 * blktrace probes
 694 */
 695
 696/**
 697 * blk_add_trace_rq - Add a trace for a request oriented action
 698 * @q:		queue the io is for
 699 * @rq:		the source request
 700 * @nr_bytes:	number of completed bytes
 701 * @what:	the action
 702 *
 703 * Description:
 704 *     Records an action against a request. Will log the bio offset + size.
 705 *
 706 **/
 707static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
 708			     unsigned int nr_bytes, u32 what)
 709{
 710	struct blk_trace *bt = q->blk_trace;
 711
 712	if (likely(!bt))
 713		return;
 714
 715	if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
 716		what |= BLK_TC_ACT(BLK_TC_PC);
 717		__blk_add_trace(bt, 0, nr_bytes, req_op(rq), rq->cmd_flags,
 718				what, rq->errors, rq->cmd_len, rq->cmd);
 719	} else  {
 720		what |= BLK_TC_ACT(BLK_TC_FS);
 721		__blk_add_trace(bt, blk_rq_pos(rq), nr_bytes, req_op(rq),
 722				rq->cmd_flags, what, rq->errors, 0, NULL);
 723	}
 724}
 725
 726static void blk_add_trace_rq_abort(void *ignore,
 727				   struct request_queue *q, struct request *rq)
 728{
 729	blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT);
 730}
 731
 732static void blk_add_trace_rq_insert(void *ignore,
 733				    struct request_queue *q, struct request *rq)
 734{
 735	blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT);
 736}
 737
 738static void blk_add_trace_rq_issue(void *ignore,
 739				   struct request_queue *q, struct request *rq)
 740{
 741	blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE);
 742}
 743
 744static void blk_add_trace_rq_requeue(void *ignore,
 745				     struct request_queue *q,
 746				     struct request *rq)
 747{
 748	blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE);
 749}
 750
 751static void blk_add_trace_rq_complete(void *ignore,
 752				      struct request_queue *q,
 753				      struct request *rq,
 754				      unsigned int nr_bytes)
 755{
 756	blk_add_trace_rq(q, rq, nr_bytes, BLK_TA_COMPLETE);
 757}
 758
 759/**
 760 * blk_add_trace_bio - Add a trace for a bio oriented action
 761 * @q:		queue the io is for
 762 * @bio:	the source bio
 763 * @what:	the action
 764 * @error:	error, if any
 765 *
 766 * Description:
 767 *     Records an action against a bio. Will log the bio offset + size.
 768 *
 769 **/
 770static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
 771			      u32 what, int error)
 772{
 773	struct blk_trace *bt = q->blk_trace;
 774
 775	if (likely(!bt))
 776		return;
 777
 778	__blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
 779			bio_op(bio), bio->bi_opf, what, error, 0, NULL);
 780}
 781
 782static void blk_add_trace_bio_bounce(void *ignore,
 783				     struct request_queue *q, struct bio *bio)
 784{
 785	blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
 786}
 787
 788static void blk_add_trace_bio_complete(void *ignore,
 789				       struct request_queue *q, struct bio *bio,
 790				       int error)
 791{
 792	blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
 793}
 794
 795static void blk_add_trace_bio_backmerge(void *ignore,
 796					struct request_queue *q,
 797					struct request *rq,
 798					struct bio *bio)
 799{
 800	blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
 801}
 802
 803static void blk_add_trace_bio_frontmerge(void *ignore,
 804					 struct request_queue *q,
 805					 struct request *rq,
 806					 struct bio *bio)
 807{
 808	blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
 809}
 810
 811static void blk_add_trace_bio_queue(void *ignore,
 812				    struct request_queue *q, struct bio *bio)
 813{
 814	blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
 815}
 816
 817static void blk_add_trace_getrq(void *ignore,
 818				struct request_queue *q,
 819				struct bio *bio, int rw)
 820{
 821	if (bio)
 822		blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
 823	else {
 824		struct blk_trace *bt = q->blk_trace;
 825
 826		if (bt)
 827			__blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
 828					NULL);
 829	}
 830}
 831
 832
 833static void blk_add_trace_sleeprq(void *ignore,
 834				  struct request_queue *q,
 835				  struct bio *bio, int rw)
 836{
 837	if (bio)
 838		blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
 839	else {
 840		struct blk_trace *bt = q->blk_trace;
 841
 842		if (bt)
 843			__blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
 844					0, 0, NULL);
 845	}
 846}
 847
 848static void blk_add_trace_plug(void *ignore, struct request_queue *q)
 849{
 850	struct blk_trace *bt = q->blk_trace;
 851
 852	if (bt)
 853		__blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
 854}
 855
 856static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
 857				    unsigned int depth, bool explicit)
 858{
 859	struct blk_trace *bt = q->blk_trace;
 860
 861	if (bt) {
 862		__be64 rpdu = cpu_to_be64(depth);
 863		u32 what;
 864
 865		if (explicit)
 866			what = BLK_TA_UNPLUG_IO;
 867		else
 868			what = BLK_TA_UNPLUG_TIMER;
 869
 870		__blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
 871	}
 872}
 873
 874static void blk_add_trace_split(void *ignore,
 875				struct request_queue *q, struct bio *bio,
 876				unsigned int pdu)
 877{
 878	struct blk_trace *bt = q->blk_trace;
 879
 880	if (bt) {
 881		__be64 rpdu = cpu_to_be64(pdu);
 882
 883		__blk_add_trace(bt, bio->bi_iter.bi_sector,
 884				bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
 885				BLK_TA_SPLIT, bio->bi_error, sizeof(rpdu),
 886				&rpdu);
 887	}
 888}
 889
 890/**
 891 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
 892 * @ignore:	trace callback data parameter (not used)
 893 * @q:		queue the io is for
 894 * @bio:	the source bio
 895 * @dev:	target device
 896 * @from:	source sector
 897 *
 898 * Description:
 899 *     Device mapper or raid target sometimes need to split a bio because
 900 *     it spans a stripe (or similar). Add a trace for that action.
 901 *
 902 **/
 903static void blk_add_trace_bio_remap(void *ignore,
 904				    struct request_queue *q, struct bio *bio,
 905				    dev_t dev, sector_t from)
 906{
 907	struct blk_trace *bt = q->blk_trace;
 908	struct blk_io_trace_remap r;
 909
 910	if (likely(!bt))
 911		return;
 912
 913	r.device_from = cpu_to_be32(dev);
 914	r.device_to   = cpu_to_be32(bio->bi_bdev->bd_dev);
 915	r.sector_from = cpu_to_be64(from);
 916
 917	__blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
 918			bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_error,
 919			sizeof(r), &r);
 920}
 921
 922/**
 923 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
 924 * @ignore:	trace callback data parameter (not used)
 925 * @q:		queue the io is for
 926 * @rq:		the source request
 927 * @dev:	target device
 928 * @from:	source sector
 929 *
 930 * Description:
 931 *     Device mapper remaps request to other devices.
 932 *     Add a trace for that action.
 933 *
 934 **/
 935static void blk_add_trace_rq_remap(void *ignore,
 936				   struct request_queue *q,
 937				   struct request *rq, dev_t dev,
 938				   sector_t from)
 939{
 940	struct blk_trace *bt = q->blk_trace;
 941	struct blk_io_trace_remap r;
 942
 943	if (likely(!bt))
 944		return;
 945
 946	r.device_from = cpu_to_be32(dev);
 947	r.device_to   = cpu_to_be32(disk_devt(rq->rq_disk));
 948	r.sector_from = cpu_to_be64(from);
 949
 950	__blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
 951			rq_data_dir(rq), 0, BLK_TA_REMAP, !!rq->errors,
 952			sizeof(r), &r);
 953}
 954
 955/**
 956 * blk_add_driver_data - Add binary message with driver-specific data
 957 * @q:		queue the io is for
 958 * @rq:		io request
 959 * @data:	driver-specific data
 960 * @len:	length of driver-specific data
 961 *
 962 * Description:
 963 *     Some drivers might want to write driver-specific data per request.
 964 *
 965 **/
 966void blk_add_driver_data(struct request_queue *q,
 967			 struct request *rq,
 968			 void *data, size_t len)
 969{
 970	struct blk_trace *bt = q->blk_trace;
 971
 972	if (likely(!bt))
 973		return;
 974
 975	if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
 976		__blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 0,
 977				BLK_TA_DRV_DATA, rq->errors, len, data);
 978	else
 979		__blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 0,
 980				BLK_TA_DRV_DATA, rq->errors, len, data);
 981}
 982EXPORT_SYMBOL_GPL(blk_add_driver_data);
 983
 984static void blk_register_tracepoints(void)
 985{
 986	int ret;
 987
 988	ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
 989	WARN_ON(ret);
 990	ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
 991	WARN_ON(ret);
 992	ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
 993	WARN_ON(ret);
 994	ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
 995	WARN_ON(ret);
 996	ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
 997	WARN_ON(ret);
 998	ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
 999	WARN_ON(ret);
1000	ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1001	WARN_ON(ret);
1002	ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1003	WARN_ON(ret);
1004	ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1005	WARN_ON(ret);
1006	ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1007	WARN_ON(ret);
1008	ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1009	WARN_ON(ret);
1010	ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1011	WARN_ON(ret);
1012	ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1013	WARN_ON(ret);
1014	ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1015	WARN_ON(ret);
1016	ret = register_trace_block_split(blk_add_trace_split, NULL);
1017	WARN_ON(ret);
1018	ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1019	WARN_ON(ret);
1020	ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1021	WARN_ON(ret);
1022}
1023
1024static void blk_unregister_tracepoints(void)
1025{
1026	unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1027	unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1028	unregister_trace_block_split(blk_add_trace_split, NULL);
1029	unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1030	unregister_trace_block_plug(blk_add_trace_plug, NULL);
1031	unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1032	unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1033	unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1034	unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1035	unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1036	unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1037	unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1038	unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1039	unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1040	unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1041	unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1042	unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1043
1044	tracepoint_synchronize_unregister();
1045}
1046
1047/*
1048 * struct blk_io_tracer formatting routines
1049 */
1050
1051static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1052{
1053	int i = 0;
1054	int tc = t->action >> BLK_TC_SHIFT;
1055
1056	if (t->action == BLK_TN_MESSAGE) {
1057		rwbs[i++] = 'N';
1058		goto out;
1059	}
1060
1061	if (tc & BLK_TC_FLUSH)
1062		rwbs[i++] = 'F';
1063
1064	if (tc & BLK_TC_DISCARD)
1065		rwbs[i++] = 'D';
1066	else if (tc & BLK_TC_WRITE)
1067		rwbs[i++] = 'W';
1068	else if (t->bytes)
1069		rwbs[i++] = 'R';
1070	else
1071		rwbs[i++] = 'N';
1072
1073	if (tc & BLK_TC_FUA)
1074		rwbs[i++] = 'F';
1075	if (tc & BLK_TC_AHEAD)
1076		rwbs[i++] = 'A';
1077	if (tc & BLK_TC_SYNC)
1078		rwbs[i++] = 'S';
1079	if (tc & BLK_TC_META)
1080		rwbs[i++] = 'M';
1081out:
1082	rwbs[i] = '\0';
1083}
1084
1085static inline
1086const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1087{
1088	return (const struct blk_io_trace *)ent;
1089}
1090
1091static inline const void *pdu_start(const struct trace_entry *ent)
1092{
1093	return te_blk_io_trace(ent) + 1;
1094}
1095
1096static inline u32 t_action(const struct trace_entry *ent)
1097{
1098	return te_blk_io_trace(ent)->action;
1099}
1100
1101static inline u32 t_bytes(const struct trace_entry *ent)
1102{
1103	return te_blk_io_trace(ent)->bytes;
1104}
1105
1106static inline u32 t_sec(const struct trace_entry *ent)
1107{
1108	return te_blk_io_trace(ent)->bytes >> 9;
1109}
1110
1111static inline unsigned long long t_sector(const struct trace_entry *ent)
1112{
1113	return te_blk_io_trace(ent)->sector;
1114}
1115
1116static inline __u16 t_error(const struct trace_entry *ent)
1117{
1118	return te_blk_io_trace(ent)->error;
1119}
1120
1121static __u64 get_pdu_int(const struct trace_entry *ent)
1122{
1123	const __u64 *val = pdu_start(ent);
1124	return be64_to_cpu(*val);
1125}
1126
1127static void get_pdu_remap(const struct trace_entry *ent,
1128			  struct blk_io_trace_remap *r)
1129{
1130	const struct blk_io_trace_remap *__r = pdu_start(ent);
1131	__u64 sector_from = __r->sector_from;
1132
1133	r->device_from = be32_to_cpu(__r->device_from);
1134	r->device_to   = be32_to_cpu(__r->device_to);
1135	r->sector_from = be64_to_cpu(sector_from);
1136}
1137
1138typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1139
1140static void blk_log_action_classic(struct trace_iterator *iter, const char *act)
1141{
1142	char rwbs[RWBS_LEN];
1143	unsigned long long ts  = iter->ts;
1144	unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1145	unsigned secs	       = (unsigned long)ts;
1146	const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1147
1148	fill_rwbs(rwbs, t);
1149
1150	trace_seq_printf(&iter->seq,
1151			 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1152			 MAJOR(t->device), MINOR(t->device), iter->cpu,
1153			 secs, nsec_rem, iter->ent->pid, act, rwbs);
1154}
1155
1156static void blk_log_action(struct trace_iterator *iter, const char *act)
1157{
1158	char rwbs[RWBS_LEN];
1159	const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1160
1161	fill_rwbs(rwbs, t);
1162	trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1163			 MAJOR(t->device), MINOR(t->device), act, rwbs);
1164}
1165
1166static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1167{
1168	const unsigned char *pdu_buf;
1169	int pdu_len;
1170	int i, end;
1171
1172	pdu_buf = pdu_start(ent);
1173	pdu_len = te_blk_io_trace(ent)->pdu_len;
1174
1175	if (!pdu_len)
1176		return;
1177
1178	/* find the last zero that needs to be printed */
1179	for (end = pdu_len - 1; end >= 0; end--)
1180		if (pdu_buf[end])
1181			break;
1182	end++;
1183
1184	trace_seq_putc(s, '(');
1185
1186	for (i = 0; i < pdu_len; i++) {
1187
1188		trace_seq_printf(s, "%s%02x",
1189				 i == 0 ? "" : " ", pdu_buf[i]);
1190
1191		/*
1192		 * stop when the rest is just zeroes and indicate so
1193		 * with a ".." appended
1194		 */
1195		if (i == end && end != pdu_len - 1) {
1196			trace_seq_puts(s, " ..) ");
1197			return;
1198		}
1199	}
1200
1201	trace_seq_puts(s, ") ");
1202}
1203
1204static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1205{
1206	char cmd[TASK_COMM_LEN];
1207
1208	trace_find_cmdline(ent->pid, cmd);
1209
1210	if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1211		trace_seq_printf(s, "%u ", t_bytes(ent));
1212		blk_log_dump_pdu(s, ent);
1213		trace_seq_printf(s, "[%s]\n", cmd);
1214	} else {
1215		if (t_sec(ent))
1216			trace_seq_printf(s, "%llu + %u [%s]\n",
1217						t_sector(ent), t_sec(ent), cmd);
1218		else
1219			trace_seq_printf(s, "[%s]\n", cmd);
1220	}
1221}
1222
1223static void blk_log_with_error(struct trace_seq *s,
1224			      const struct trace_entry *ent)
1225{
1226	if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1227		blk_log_dump_pdu(s, ent);
1228		trace_seq_printf(s, "[%d]\n", t_error(ent));
1229	} else {
1230		if (t_sec(ent))
1231			trace_seq_printf(s, "%llu + %u [%d]\n",
1232					 t_sector(ent),
1233					 t_sec(ent), t_error(ent));
1234		else
1235			trace_seq_printf(s, "%llu [%d]\n",
1236					 t_sector(ent), t_error(ent));
1237	}
1238}
1239
1240static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1241{
1242	struct blk_io_trace_remap r = { .device_from = 0, };
1243
1244	get_pdu_remap(ent, &r);
1245	trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1246			 t_sector(ent), t_sec(ent),
1247			 MAJOR(r.device_from), MINOR(r.device_from),
1248			 (unsigned long long)r.sector_from);
1249}
1250
1251static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1252{
1253	char cmd[TASK_COMM_LEN];
1254
1255	trace_find_cmdline(ent->pid, cmd);
1256
1257	trace_seq_printf(s, "[%s]\n", cmd);
1258}
1259
1260static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1261{
1262	char cmd[TASK_COMM_LEN];
1263
1264	trace_find_cmdline(ent->pid, cmd);
1265
1266	trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1267}
1268
1269static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1270{
1271	char cmd[TASK_COMM_LEN];
1272
1273	trace_find_cmdline(ent->pid, cmd);
1274
1275	trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1276			 get_pdu_int(ent), cmd);
1277}
1278
1279static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1280{
1281	const struct blk_io_trace *t = te_blk_io_trace(ent);
1282
1283	trace_seq_putmem(s, t + 1, t->pdu_len);
1284	trace_seq_putc(s, '\n');
1285}
1286
1287/*
1288 * struct tracer operations
1289 */
1290
1291static void blk_tracer_print_header(struct seq_file *m)
1292{
1293	if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1294		return;
1295	seq_puts(m, "# DEV   CPU TIMESTAMP     PID ACT FLG\n"
1296		    "#  |     |     |           |   |   |\n");
1297}
1298
1299static void blk_tracer_start(struct trace_array *tr)
1300{
1301	blk_tracer_enabled = true;
1302}
1303
1304static int blk_tracer_init(struct trace_array *tr)
1305{
1306	blk_tr = tr;
1307	blk_tracer_start(tr);
1308	return 0;
1309}
1310
1311static void blk_tracer_stop(struct trace_array *tr)
1312{
1313	blk_tracer_enabled = false;
1314}
1315
1316static void blk_tracer_reset(struct trace_array *tr)
1317{
1318	blk_tracer_stop(tr);
1319}
1320
1321static const struct {
1322	const char *act[2];
1323	void	   (*print)(struct trace_seq *s, const struct trace_entry *ent);
1324} what2act[] = {
1325	[__BLK_TA_QUEUE]	= {{  "Q", "queue" },	   blk_log_generic },
1326	[__BLK_TA_BACKMERGE]	= {{  "M", "backmerge" },  blk_log_generic },
1327	[__BLK_TA_FRONTMERGE]	= {{  "F", "frontmerge" }, blk_log_generic },
1328	[__BLK_TA_GETRQ]	= {{  "G", "getrq" },	   blk_log_generic },
1329	[__BLK_TA_SLEEPRQ]	= {{  "S", "sleeprq" },	   blk_log_generic },
1330	[__BLK_TA_REQUEUE]	= {{  "R", "requeue" },	   blk_log_with_error },
1331	[__BLK_TA_ISSUE]	= {{  "D", "issue" },	   blk_log_generic },
1332	[__BLK_TA_COMPLETE]	= {{  "C", "complete" },   blk_log_with_error },
1333	[__BLK_TA_PLUG]		= {{  "P", "plug" },	   blk_log_plug },
1334	[__BLK_TA_UNPLUG_IO]	= {{  "U", "unplug_io" },  blk_log_unplug },
1335	[__BLK_TA_UNPLUG_TIMER]	= {{ "UT", "unplug_timer" }, blk_log_unplug },
1336	[__BLK_TA_INSERT]	= {{  "I", "insert" },	   blk_log_generic },
1337	[__BLK_TA_SPLIT]	= {{  "X", "split" },	   blk_log_split },
1338	[__BLK_TA_BOUNCE]	= {{  "B", "bounce" },	   blk_log_generic },
1339	[__BLK_TA_REMAP]	= {{  "A", "remap" },	   blk_log_remap },
1340};
1341
1342static enum print_line_t print_one_line(struct trace_iterator *iter,
1343					bool classic)
1344{
1345	struct trace_array *tr = iter->tr;
1346	struct trace_seq *s = &iter->seq;
1347	const struct blk_io_trace *t;
1348	u16 what;
1349	bool long_act;
1350	blk_log_action_t *log_action;
1351
1352	t	   = te_blk_io_trace(iter->ent);
1353	what	   = t->action & ((1 << BLK_TC_SHIFT) - 1);
1354	long_act   = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1355	log_action = classic ? &blk_log_action_classic : &blk_log_action;
1356
1357	if (t->action == BLK_TN_MESSAGE) {
1358		log_action(iter, long_act ? "message" : "m");
1359		blk_log_msg(s, iter->ent);
1360		return trace_handle_return(s);
1361	}
1362
1363	if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1364		trace_seq_printf(s, "Unknown action %x\n", what);
1365	else {
1366		log_action(iter, what2act[what].act[long_act]);
1367		what2act[what].print(s, iter->ent);
1368	}
1369
1370	return trace_handle_return(s);
1371}
1372
1373static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1374					       int flags, struct trace_event *event)
1375{
1376	return print_one_line(iter, false);
1377}
1378
1379static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1380{
1381	struct trace_seq *s = &iter->seq;
1382	struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1383	const int offset = offsetof(struct blk_io_trace, sector);
1384	struct blk_io_trace old = {
1385		.magic	  = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1386		.time     = iter->ts,
1387	};
1388
1389	trace_seq_putmem(s, &old, offset);
1390	trace_seq_putmem(s, &t->sector,
1391			 sizeof(old) - offset + t->pdu_len);
1392}
1393
1394static enum print_line_t
1395blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1396			     struct trace_event *event)
1397{
1398	blk_trace_synthesize_old_trace(iter);
1399
1400	return trace_handle_return(&iter->seq);
1401}
1402
1403static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1404{
1405	if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1406		return TRACE_TYPE_UNHANDLED;
1407
1408	return print_one_line(iter, true);
1409}
1410
1411static int
1412blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1413{
1414	/* don't output context-info for blk_classic output */
1415	if (bit == TRACE_BLK_OPT_CLASSIC) {
1416		if (set)
1417			tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1418		else
1419			tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1420	}
1421	return 0;
1422}
1423
1424static struct tracer blk_tracer __read_mostly = {
1425	.name		= "blk",
1426	.init		= blk_tracer_init,
1427	.reset		= blk_tracer_reset,
1428	.start		= blk_tracer_start,
1429	.stop		= blk_tracer_stop,
1430	.print_header	= blk_tracer_print_header,
1431	.print_line	= blk_tracer_print_line,
1432	.flags		= &blk_tracer_flags,
1433	.set_flag	= blk_tracer_set_flag,
1434};
1435
1436static struct trace_event_functions trace_blk_event_funcs = {
1437	.trace		= blk_trace_event_print,
1438	.binary		= blk_trace_event_print_binary,
1439};
1440
1441static struct trace_event trace_blk_event = {
1442	.type		= TRACE_BLK,
1443	.funcs		= &trace_blk_event_funcs,
1444};
1445
1446static int __init init_blk_tracer(void)
1447{
1448	if (!register_trace_event(&trace_blk_event)) {
1449		pr_warn("Warning: could not register block events\n");
1450		return 1;
1451	}
1452
1453	if (register_tracer(&blk_tracer) != 0) {
1454		pr_warn("Warning: could not register the block tracer\n");
1455		unregister_trace_event(&trace_blk_event);
1456		return 1;
1457	}
1458
1459	return 0;
1460}
1461
1462device_initcall(init_blk_tracer);
1463
1464static int blk_trace_remove_queue(struct request_queue *q)
1465{
1466	struct blk_trace *bt;
1467
1468	bt = xchg(&q->blk_trace, NULL);
1469	if (bt == NULL)
1470		return -EINVAL;
1471
1472	if (atomic_dec_and_test(&blk_probes_ref))
1473		blk_unregister_tracepoints();
1474
1475	blk_trace_free(bt);
1476	return 0;
1477}
1478
1479/*
1480 * Setup everything required to start tracing
1481 */
1482static int blk_trace_setup_queue(struct request_queue *q,
1483				 struct block_device *bdev)
1484{
1485	struct blk_trace *bt = NULL;
1486	int ret = -ENOMEM;
1487
1488	bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1489	if (!bt)
1490		return -ENOMEM;
1491
1492	bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1493	if (!bt->msg_data)
1494		goto free_bt;
1495
1496	bt->dev = bdev->bd_dev;
1497	bt->act_mask = (u16)-1;
1498
1499	blk_trace_setup_lba(bt, bdev);
1500
1501	ret = -EBUSY;
1502	if (cmpxchg(&q->blk_trace, NULL, bt))
1503		goto free_bt;
1504
1505	if (atomic_inc_return(&blk_probes_ref) == 1)
1506		blk_register_tracepoints();
1507	return 0;
1508
1509free_bt:
1510	blk_trace_free(bt);
1511	return ret;
1512}
1513
1514/*
1515 * sysfs interface to enable and configure tracing
1516 */
1517
1518static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1519					 struct device_attribute *attr,
1520					 char *buf);
1521static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1522					  struct device_attribute *attr,
1523					  const char *buf, size_t count);
1524#define BLK_TRACE_DEVICE_ATTR(_name) \
1525	DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1526		    sysfs_blk_trace_attr_show, \
1527		    sysfs_blk_trace_attr_store)
1528
1529static BLK_TRACE_DEVICE_ATTR(enable);
1530static BLK_TRACE_DEVICE_ATTR(act_mask);
1531static BLK_TRACE_DEVICE_ATTR(pid);
1532static BLK_TRACE_DEVICE_ATTR(start_lba);
1533static BLK_TRACE_DEVICE_ATTR(end_lba);
1534
1535static struct attribute *blk_trace_attrs[] = {
1536	&dev_attr_enable.attr,
1537	&dev_attr_act_mask.attr,
1538	&dev_attr_pid.attr,
1539	&dev_attr_start_lba.attr,
1540	&dev_attr_end_lba.attr,
1541	NULL
1542};
1543
1544struct attribute_group blk_trace_attr_group = {
1545	.name  = "trace",
1546	.attrs = blk_trace_attrs,
1547};
1548
1549static const struct {
1550	int mask;
1551	const char *str;
1552} mask_maps[] = {
1553	{ BLK_TC_READ,		"read"		},
1554	{ BLK_TC_WRITE,		"write"		},
1555	{ BLK_TC_FLUSH,		"flush"		},
1556	{ BLK_TC_SYNC,		"sync"		},
1557	{ BLK_TC_QUEUE,		"queue"		},
1558	{ BLK_TC_REQUEUE,	"requeue"	},
1559	{ BLK_TC_ISSUE,		"issue"		},
1560	{ BLK_TC_COMPLETE,	"complete"	},
1561	{ BLK_TC_FS,		"fs"		},
1562	{ BLK_TC_PC,		"pc"		},
1563	{ BLK_TC_NOTIFY,	"notify"	},
1564	{ BLK_TC_AHEAD,		"ahead"		},
1565	{ BLK_TC_META,		"meta"		},
1566	{ BLK_TC_DISCARD,	"discard"	},
1567	{ BLK_TC_DRV_DATA,	"drv_data"	},
1568	{ BLK_TC_FUA,		"fua"		},
1569};
1570
1571static int blk_trace_str2mask(const char *str)
1572{
1573	int i;
1574	int mask = 0;
1575	char *buf, *s, *token;
1576
1577	buf = kstrdup(str, GFP_KERNEL);
1578	if (buf == NULL)
1579		return -ENOMEM;
1580	s = strstrip(buf);
1581
1582	while (1) {
1583		token = strsep(&s, ",");
1584		if (token == NULL)
1585			break;
1586
1587		if (*token == '\0')
1588			continue;
1589
1590		for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1591			if (strcasecmp(token, mask_maps[i].str) == 0) {
1592				mask |= mask_maps[i].mask;
1593				break;
1594			}
1595		}
1596		if (i == ARRAY_SIZE(mask_maps)) {
1597			mask = -EINVAL;
1598			break;
1599		}
1600	}
1601	kfree(buf);
1602
1603	return mask;
1604}
1605
1606static ssize_t blk_trace_mask2str(char *buf, int mask)
1607{
1608	int i;
1609	char *p = buf;
1610
1611	for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1612		if (mask & mask_maps[i].mask) {
1613			p += sprintf(p, "%s%s",
1614				    (p == buf) ? "" : ",", mask_maps[i].str);
1615		}
1616	}
1617	*p++ = '\n';
1618
1619	return p - buf;
1620}
1621
1622static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1623{
1624	if (bdev->bd_disk == NULL)
1625		return NULL;
1626
1627	return bdev_get_queue(bdev);
1628}
1629
1630static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1631					 struct device_attribute *attr,
1632					 char *buf)
1633{
1634	struct hd_struct *p = dev_to_part(dev);
1635	struct request_queue *q;
1636	struct block_device *bdev;
1637	ssize_t ret = -ENXIO;
1638
1639	bdev = bdget(part_devt(p));
1640	if (bdev == NULL)
1641		goto out;
1642
1643	q = blk_trace_get_queue(bdev);
1644	if (q == NULL)
1645		goto out_bdput;
1646
1647	mutex_lock(&bdev->bd_mutex);
1648
1649	if (attr == &dev_attr_enable) {
1650		ret = sprintf(buf, "%u\n", !!q->blk_trace);
1651		goto out_unlock_bdev;
1652	}
1653
1654	if (q->blk_trace == NULL)
1655		ret = sprintf(buf, "disabled\n");
1656	else if (attr == &dev_attr_act_mask)
1657		ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1658	else if (attr == &dev_attr_pid)
1659		ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1660	else if (attr == &dev_attr_start_lba)
1661		ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1662	else if (attr == &dev_attr_end_lba)
1663		ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1664
1665out_unlock_bdev:
1666	mutex_unlock(&bdev->bd_mutex);
1667out_bdput:
1668	bdput(bdev);
1669out:
1670	return ret;
1671}
1672
1673static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1674					  struct device_attribute *attr,
1675					  const char *buf, size_t count)
1676{
1677	struct block_device *bdev;
1678	struct request_queue *q;
1679	struct hd_struct *p;
1680	u64 value;
1681	ssize_t ret = -EINVAL;
1682
1683	if (count == 0)
1684		goto out;
1685
1686	if (attr == &dev_attr_act_mask) {
1687		if (sscanf(buf, "%llx", &value) != 1) {
1688			/* Assume it is a list of trace category names */
1689			ret = blk_trace_str2mask(buf);
1690			if (ret < 0)
1691				goto out;
1692			value = ret;
1693		}
1694	} else if (sscanf(buf, "%llu", &value) != 1)
1695		goto out;
1696
1697	ret = -ENXIO;
1698
1699	p = dev_to_part(dev);
1700	bdev = bdget(part_devt(p));
1701	if (bdev == NULL)
1702		goto out;
1703
1704	q = blk_trace_get_queue(bdev);
1705	if (q == NULL)
1706		goto out_bdput;
1707
1708	mutex_lock(&bdev->bd_mutex);
1709
1710	if (attr == &dev_attr_enable) {
1711		if (value)
1712			ret = blk_trace_setup_queue(q, bdev);
1713		else
1714			ret = blk_trace_remove_queue(q);
1715		goto out_unlock_bdev;
1716	}
1717
1718	ret = 0;
1719	if (q->blk_trace == NULL)
1720		ret = blk_trace_setup_queue(q, bdev);
1721
1722	if (ret == 0) {
1723		if (attr == &dev_attr_act_mask)
1724			q->blk_trace->act_mask = value;
1725		else if (attr == &dev_attr_pid)
1726			q->blk_trace->pid = value;
1727		else if (attr == &dev_attr_start_lba)
1728			q->blk_trace->start_lba = value;
1729		else if (attr == &dev_attr_end_lba)
1730			q->blk_trace->end_lba = value;
1731	}
1732
1733out_unlock_bdev:
1734	mutex_unlock(&bdev->bd_mutex);
1735out_bdput:
1736	bdput(bdev);
1737out:
1738	return ret ? ret : count;
1739}
1740
1741int blk_trace_init_sysfs(struct device *dev)
1742{
1743	return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1744}
1745
1746void blk_trace_remove_sysfs(struct device *dev)
1747{
1748	sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1749}
1750
1751#endif /* CONFIG_BLK_DEV_IO_TRACE */
1752
1753#ifdef CONFIG_EVENT_TRACING
1754
1755void blk_dump_cmd(char *buf, struct request *rq)
1756{
1757	int i, end;
1758	int len = rq->cmd_len;
1759	unsigned char *cmd = rq->cmd;
1760
1761	if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1762		buf[0] = '\0';
1763		return;
1764	}
1765
1766	for (end = len - 1; end >= 0; end--)
1767		if (cmd[end])
1768			break;
1769	end++;
1770
1771	for (i = 0; i < len; i++) {
1772		buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1773		if (i == end && end != len - 1) {
1774			sprintf(buf, " ..");
1775			break;
1776		}
1777	}
1778}
1779
1780void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
1781{
1782	int i = 0;
1783
1784	if (op & REQ_PREFLUSH)
1785		rwbs[i++] = 'F';
1786
1787	switch (op & REQ_OP_MASK) {
1788	case REQ_OP_WRITE:
1789	case REQ_OP_WRITE_SAME:
1790		rwbs[i++] = 'W';
1791		break;
1792	case REQ_OP_DISCARD:
1793		rwbs[i++] = 'D';
1794		break;
1795	case REQ_OP_SECURE_ERASE:
1796		rwbs[i++] = 'D';
1797		rwbs[i++] = 'E';
1798		break;
1799	case REQ_OP_FLUSH:
1800		rwbs[i++] = 'F';
1801		break;
1802	case REQ_OP_READ:
1803		rwbs[i++] = 'R';
1804		break;
1805	default:
1806		rwbs[i++] = 'N';
1807	}
1808
1809	if (op & REQ_FUA)
1810		rwbs[i++] = 'F';
1811	if (op & REQ_RAHEAD)
1812		rwbs[i++] = 'A';
1813	if (op & REQ_SYNC)
1814		rwbs[i++] = 'S';
1815	if (op & REQ_META)
1816		rwbs[i++] = 'M';
 
 
1817
1818	rwbs[i] = '\0';
1819}
1820EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1821
1822#endif /* CONFIG_EVENT_TRACING */
1823