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