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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
4 *
5 */
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/kernel.h>
10#include <linux/blkdev.h>
11#include <linux/blktrace_api.h>
12#include <linux/percpu.h>
13#include <linux/init.h>
14#include <linux/mutex.h>
15#include <linux/slab.h>
16#include <linux/debugfs.h>
17#include <linux/export.h>
18#include <linux/time.h>
19#include <linux/uaccess.h>
20#include <linux/list.h>
21#include <linux/blk-cgroup.h>
22
23#include "../../block/blk.h"
24
25#include <trace/events/block.h>
26
27#include "trace_output.h"
28
29#ifdef CONFIG_BLK_DEV_IO_TRACE
30
31static unsigned int blktrace_seq __read_mostly = 1;
32
33static struct trace_array *blk_tr;
34static bool blk_tracer_enabled __read_mostly;
35
36static LIST_HEAD(running_trace_list);
37static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
38
39/* Select an alternative, minimalistic output than the original one */
40#define TRACE_BLK_OPT_CLASSIC 0x1
41#define TRACE_BLK_OPT_CGROUP 0x2
42#define TRACE_BLK_OPT_CGNAME 0x4
43
44static struct tracer_opt blk_tracer_opts[] = {
45 /* Default disable the minimalistic output */
46 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
47#ifdef CONFIG_BLK_CGROUP
48 { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
49 { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
50#endif
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 DEFINE_MUTEX(blk_probe_mutex);
61static int blk_probes_ref;
62
63static void blk_register_tracepoints(void);
64static void blk_unregister_tracepoints(void);
65
66/*
67 * Send out a notify message.
68 */
69static void trace_note(struct blk_trace *bt, pid_t pid, int action,
70 const void *data, size_t len, u64 cgid)
71{
72 struct blk_io_trace *t;
73 struct ring_buffer_event *event = NULL;
74 struct trace_buffer *buffer = NULL;
75 unsigned int trace_ctx = 0;
76 int cpu = smp_processor_id();
77 bool blk_tracer = blk_tracer_enabled;
78 ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
79
80 if (blk_tracer) {
81 buffer = blk_tr->array_buffer.buffer;
82 trace_ctx = tracing_gen_ctx_flags(0);
83 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
84 sizeof(*t) + len + cgid_len,
85 trace_ctx);
86 if (!event)
87 return;
88 t = ring_buffer_event_data(event);
89 goto record_it;
90 }
91
92 if (!bt->rchan)
93 return;
94
95 t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len);
96 if (t) {
97 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
98 t->time = ktime_to_ns(ktime_get());
99record_it:
100 t->device = bt->dev;
101 t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
102 t->pid = pid;
103 t->cpu = cpu;
104 t->pdu_len = len + cgid_len;
105 if (cgid_len)
106 memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
107 memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
108
109 if (blk_tracer)
110 trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
111 }
112}
113
114/*
115 * Send out a notify for this process, if we haven't done so since a trace
116 * started
117 */
118static void trace_note_tsk(struct task_struct *tsk)
119{
120 unsigned long flags;
121 struct blk_trace *bt;
122
123 tsk->btrace_seq = blktrace_seq;
124 spin_lock_irqsave(&running_trace_lock, flags);
125 list_for_each_entry(bt, &running_trace_list, running_list) {
126 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
127 sizeof(tsk->comm), 0);
128 }
129 spin_unlock_irqrestore(&running_trace_lock, flags);
130}
131
132static void trace_note_time(struct blk_trace *bt)
133{
134 struct timespec64 now;
135 unsigned long flags;
136 u32 words[2];
137
138 /* need to check user space to see if this breaks in y2038 or y2106 */
139 ktime_get_real_ts64(&now);
140 words[0] = (u32)now.tv_sec;
141 words[1] = now.tv_nsec;
142
143 local_irq_save(flags);
144 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), 0);
145 local_irq_restore(flags);
146}
147
148void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
149 const char *fmt, ...)
150{
151 int n;
152 va_list args;
153 unsigned long flags;
154 char *buf;
155
156 if (unlikely(bt->trace_state != Blktrace_running &&
157 !blk_tracer_enabled))
158 return;
159
160 /*
161 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
162 * message to the trace.
163 */
164 if (!(bt->act_mask & BLK_TC_NOTIFY))
165 return;
166
167 local_irq_save(flags);
168 buf = this_cpu_ptr(bt->msg_data);
169 va_start(args, fmt);
170 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
171 va_end(args);
172
173 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
174 blkcg = NULL;
175#ifdef CONFIG_BLK_CGROUP
176 trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n,
177 blkcg ? cgroup_id(blkcg->css.cgroup) : 1);
178#else
179 trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n, 0);
180#endif
181 local_irq_restore(flags);
182}
183EXPORT_SYMBOL_GPL(__trace_note_message);
184
185static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
186 pid_t pid)
187{
188 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
189 return 1;
190 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
191 return 1;
192 if (bt->pid && pid != bt->pid)
193 return 1;
194
195 return 0;
196}
197
198/*
199 * Data direction bit lookup
200 */
201static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
202 BLK_TC_ACT(BLK_TC_WRITE) };
203
204#define BLK_TC_RAHEAD BLK_TC_AHEAD
205#define BLK_TC_PREFLUSH BLK_TC_FLUSH
206
207/* The ilog2() calls fall out because they're constant */
208#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
209 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
210
211/*
212 * The worker for the various blk_add_trace*() types. Fills out a
213 * blk_io_trace structure and places it in a per-cpu subbuffer.
214 */
215static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
216 int op, int op_flags, u32 what, int error, int pdu_len,
217 void *pdu_data, u64 cgid)
218{
219 struct task_struct *tsk = current;
220 struct ring_buffer_event *event = NULL;
221 struct trace_buffer *buffer = NULL;
222 struct blk_io_trace *t;
223 unsigned long flags = 0;
224 unsigned long *sequence;
225 unsigned int trace_ctx = 0;
226 pid_t pid;
227 int cpu;
228 bool blk_tracer = blk_tracer_enabled;
229 ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
230
231 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
232 return;
233
234 what |= ddir_act[op_is_write(op) ? WRITE : READ];
235 what |= MASK_TC_BIT(op_flags, SYNC);
236 what |= MASK_TC_BIT(op_flags, RAHEAD);
237 what |= MASK_TC_BIT(op_flags, META);
238 what |= MASK_TC_BIT(op_flags, PREFLUSH);
239 what |= MASK_TC_BIT(op_flags, FUA);
240 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
241 what |= BLK_TC_ACT(BLK_TC_DISCARD);
242 if (op == REQ_OP_FLUSH)
243 what |= BLK_TC_ACT(BLK_TC_FLUSH);
244 if (cgid)
245 what |= __BLK_TA_CGROUP;
246
247 pid = tsk->pid;
248 if (act_log_check(bt, what, sector, pid))
249 return;
250 cpu = raw_smp_processor_id();
251
252 if (blk_tracer) {
253 tracing_record_cmdline(current);
254
255 buffer = blk_tr->array_buffer.buffer;
256 trace_ctx = tracing_gen_ctx_flags(0);
257 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
258 sizeof(*t) + pdu_len + cgid_len,
259 trace_ctx);
260 if (!event)
261 return;
262 t = ring_buffer_event_data(event);
263 goto record_it;
264 }
265
266 if (unlikely(tsk->btrace_seq != blktrace_seq))
267 trace_note_tsk(tsk);
268
269 /*
270 * A word about the locking here - we disable interrupts to reserve
271 * some space in the relay per-cpu buffer, to prevent an irq
272 * from coming in and stepping on our toes.
273 */
274 local_irq_save(flags);
275 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
276 if (t) {
277 sequence = per_cpu_ptr(bt->sequence, cpu);
278
279 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
280 t->sequence = ++(*sequence);
281 t->time = ktime_to_ns(ktime_get());
282record_it:
283 /*
284 * These two are not needed in ftrace as they are in the
285 * generic trace_entry, filled by tracing_generic_entry_update,
286 * but for the trace_event->bin() synthesizer benefit we do it
287 * here too.
288 */
289 t->cpu = cpu;
290 t->pid = pid;
291
292 t->sector = sector;
293 t->bytes = bytes;
294 t->action = what;
295 t->device = bt->dev;
296 t->error = error;
297 t->pdu_len = pdu_len + cgid_len;
298
299 if (cgid_len)
300 memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
301 if (pdu_len)
302 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
303
304 if (blk_tracer) {
305 trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
306 return;
307 }
308 }
309
310 local_irq_restore(flags);
311}
312
313static void blk_trace_free(struct blk_trace *bt)
314{
315 relay_close(bt->rchan);
316 debugfs_remove(bt->dir);
317 free_percpu(bt->sequence);
318 free_percpu(bt->msg_data);
319 kfree(bt);
320}
321
322static void get_probe_ref(void)
323{
324 mutex_lock(&blk_probe_mutex);
325 if (++blk_probes_ref == 1)
326 blk_register_tracepoints();
327 mutex_unlock(&blk_probe_mutex);
328}
329
330static void put_probe_ref(void)
331{
332 mutex_lock(&blk_probe_mutex);
333 if (!--blk_probes_ref)
334 blk_unregister_tracepoints();
335 mutex_unlock(&blk_probe_mutex);
336}
337
338static void blk_trace_cleanup(struct blk_trace *bt)
339{
340 synchronize_rcu();
341 blk_trace_free(bt);
342 put_probe_ref();
343}
344
345static int __blk_trace_remove(struct request_queue *q)
346{
347 struct blk_trace *bt;
348
349 bt = rcu_replace_pointer(q->blk_trace, NULL,
350 lockdep_is_held(&q->debugfs_mutex));
351 if (!bt)
352 return -EINVAL;
353
354 if (bt->trace_state != Blktrace_running)
355 blk_trace_cleanup(bt);
356
357 return 0;
358}
359
360int blk_trace_remove(struct request_queue *q)
361{
362 int ret;
363
364 mutex_lock(&q->debugfs_mutex);
365 ret = __blk_trace_remove(q);
366 mutex_unlock(&q->debugfs_mutex);
367
368 return ret;
369}
370EXPORT_SYMBOL_GPL(blk_trace_remove);
371
372static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
373 size_t count, loff_t *ppos)
374{
375 struct blk_trace *bt = filp->private_data;
376 char buf[16];
377
378 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
379
380 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
381}
382
383static const struct file_operations blk_dropped_fops = {
384 .owner = THIS_MODULE,
385 .open = simple_open,
386 .read = blk_dropped_read,
387 .llseek = default_llseek,
388};
389
390static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
391 size_t count, loff_t *ppos)
392{
393 char *msg;
394 struct blk_trace *bt;
395
396 if (count >= BLK_TN_MAX_MSG)
397 return -EINVAL;
398
399 msg = memdup_user_nul(buffer, count);
400 if (IS_ERR(msg))
401 return PTR_ERR(msg);
402
403 bt = filp->private_data;
404 __trace_note_message(bt, NULL, "%s", msg);
405 kfree(msg);
406
407 return count;
408}
409
410static const struct file_operations blk_msg_fops = {
411 .owner = THIS_MODULE,
412 .open = simple_open,
413 .write = blk_msg_write,
414 .llseek = noop_llseek,
415};
416
417/*
418 * Keep track of how many times we encountered a full subbuffer, to aid
419 * the user space app in telling how many lost events there were.
420 */
421static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
422 void *prev_subbuf, size_t prev_padding)
423{
424 struct blk_trace *bt;
425
426 if (!relay_buf_full(buf))
427 return 1;
428
429 bt = buf->chan->private_data;
430 atomic_inc(&bt->dropped);
431 return 0;
432}
433
434static int blk_remove_buf_file_callback(struct dentry *dentry)
435{
436 debugfs_remove(dentry);
437
438 return 0;
439}
440
441static struct dentry *blk_create_buf_file_callback(const char *filename,
442 struct dentry *parent,
443 umode_t mode,
444 struct rchan_buf *buf,
445 int *is_global)
446{
447 return debugfs_create_file(filename, mode, parent, buf,
448 &relay_file_operations);
449}
450
451static const struct rchan_callbacks blk_relay_callbacks = {
452 .subbuf_start = blk_subbuf_start_callback,
453 .create_buf_file = blk_create_buf_file_callback,
454 .remove_buf_file = blk_remove_buf_file_callback,
455};
456
457static void blk_trace_setup_lba(struct blk_trace *bt,
458 struct block_device *bdev)
459{
460 if (bdev) {
461 bt->start_lba = bdev->bd_start_sect;
462 bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev);
463 } else {
464 bt->start_lba = 0;
465 bt->end_lba = -1ULL;
466 }
467}
468
469/*
470 * Setup everything required to start tracing
471 */
472static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
473 struct block_device *bdev,
474 struct blk_user_trace_setup *buts)
475{
476 struct blk_trace *bt = NULL;
477 struct dentry *dir = NULL;
478 int ret;
479
480 lockdep_assert_held(&q->debugfs_mutex);
481
482 if (!buts->buf_size || !buts->buf_nr)
483 return -EINVAL;
484
485 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
486 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
487
488 /*
489 * some device names have larger paths - convert the slashes
490 * to underscores for this to work as expected
491 */
492 strreplace(buts->name, '/', '_');
493
494 /*
495 * bdev can be NULL, as with scsi-generic, this is a helpful as
496 * we can be.
497 */
498 if (rcu_dereference_protected(q->blk_trace,
499 lockdep_is_held(&q->debugfs_mutex))) {
500 pr_warn("Concurrent blktraces are not allowed on %s\n",
501 buts->name);
502 return -EBUSY;
503 }
504
505 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
506 if (!bt)
507 return -ENOMEM;
508
509 ret = -ENOMEM;
510 bt->sequence = alloc_percpu(unsigned long);
511 if (!bt->sequence)
512 goto err;
513
514 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
515 if (!bt->msg_data)
516 goto err;
517
518 /*
519 * When tracing the whole disk reuse the existing debugfs directory
520 * created by the block layer on init. For partitions block devices,
521 * and scsi-generic block devices we create a temporary new debugfs
522 * directory that will be removed once the trace ends.
523 */
524 if (bdev && !bdev_is_partition(bdev))
525 dir = q->debugfs_dir;
526 else
527 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
528
529 /*
530 * As blktrace relies on debugfs for its interface the debugfs directory
531 * is required, contrary to the usual mantra of not checking for debugfs
532 * files or directories.
533 */
534 if (IS_ERR_OR_NULL(dir)) {
535 pr_warn("debugfs_dir not present for %s so skipping\n",
536 buts->name);
537 ret = -ENOENT;
538 goto err;
539 }
540
541 bt->dev = dev;
542 atomic_set(&bt->dropped, 0);
543 INIT_LIST_HEAD(&bt->running_list);
544
545 ret = -EIO;
546 debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
547 debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
548
549 bt->rchan = relay_open("trace", dir, buts->buf_size,
550 buts->buf_nr, &blk_relay_callbacks, bt);
551 if (!bt->rchan)
552 goto err;
553
554 bt->act_mask = buts->act_mask;
555 if (!bt->act_mask)
556 bt->act_mask = (u16) -1;
557
558 blk_trace_setup_lba(bt, bdev);
559
560 /* overwrite with user settings */
561 if (buts->start_lba)
562 bt->start_lba = buts->start_lba;
563 if (buts->end_lba)
564 bt->end_lba = buts->end_lba;
565
566 bt->pid = buts->pid;
567 bt->trace_state = Blktrace_setup;
568
569 rcu_assign_pointer(q->blk_trace, bt);
570 get_probe_ref();
571
572 ret = 0;
573err:
574 if (ret)
575 blk_trace_free(bt);
576 return ret;
577}
578
579static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
580 struct block_device *bdev, char __user *arg)
581{
582 struct blk_user_trace_setup buts;
583 int ret;
584
585 ret = copy_from_user(&buts, arg, sizeof(buts));
586 if (ret)
587 return -EFAULT;
588
589 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
590 if (ret)
591 return ret;
592
593 if (copy_to_user(arg, &buts, sizeof(buts))) {
594 __blk_trace_remove(q);
595 return -EFAULT;
596 }
597 return 0;
598}
599
600int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
601 struct block_device *bdev,
602 char __user *arg)
603{
604 int ret;
605
606 mutex_lock(&q->debugfs_mutex);
607 ret = __blk_trace_setup(q, name, dev, bdev, arg);
608 mutex_unlock(&q->debugfs_mutex);
609
610 return ret;
611}
612EXPORT_SYMBOL_GPL(blk_trace_setup);
613
614#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
615static int compat_blk_trace_setup(struct request_queue *q, char *name,
616 dev_t dev, struct block_device *bdev,
617 char __user *arg)
618{
619 struct blk_user_trace_setup buts;
620 struct compat_blk_user_trace_setup cbuts;
621 int ret;
622
623 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
624 return -EFAULT;
625
626 buts = (struct blk_user_trace_setup) {
627 .act_mask = cbuts.act_mask,
628 .buf_size = cbuts.buf_size,
629 .buf_nr = cbuts.buf_nr,
630 .start_lba = cbuts.start_lba,
631 .end_lba = cbuts.end_lba,
632 .pid = cbuts.pid,
633 };
634
635 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
636 if (ret)
637 return ret;
638
639 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
640 __blk_trace_remove(q);
641 return -EFAULT;
642 }
643
644 return 0;
645}
646#endif
647
648static int __blk_trace_startstop(struct request_queue *q, int start)
649{
650 int ret;
651 struct blk_trace *bt;
652
653 bt = rcu_dereference_protected(q->blk_trace,
654 lockdep_is_held(&q->debugfs_mutex));
655 if (bt == NULL)
656 return -EINVAL;
657
658 /*
659 * For starting a trace, we can transition from a setup or stopped
660 * trace. For stopping a trace, the state must be running
661 */
662 ret = -EINVAL;
663 if (start) {
664 if (bt->trace_state == Blktrace_setup ||
665 bt->trace_state == Blktrace_stopped) {
666 blktrace_seq++;
667 smp_mb();
668 bt->trace_state = Blktrace_running;
669 spin_lock_irq(&running_trace_lock);
670 list_add(&bt->running_list, &running_trace_list);
671 spin_unlock_irq(&running_trace_lock);
672
673 trace_note_time(bt);
674 ret = 0;
675 }
676 } else {
677 if (bt->trace_state == Blktrace_running) {
678 bt->trace_state = Blktrace_stopped;
679 spin_lock_irq(&running_trace_lock);
680 list_del_init(&bt->running_list);
681 spin_unlock_irq(&running_trace_lock);
682 relay_flush(bt->rchan);
683 ret = 0;
684 }
685 }
686
687 return ret;
688}
689
690int blk_trace_startstop(struct request_queue *q, int start)
691{
692 int ret;
693
694 mutex_lock(&q->debugfs_mutex);
695 ret = __blk_trace_startstop(q, start);
696 mutex_unlock(&q->debugfs_mutex);
697
698 return ret;
699}
700EXPORT_SYMBOL_GPL(blk_trace_startstop);
701
702/*
703 * When reading or writing the blktrace sysfs files, the references to the
704 * opened sysfs or device files should prevent the underlying block device
705 * from being removed. So no further delete protection is really needed.
706 */
707
708/**
709 * blk_trace_ioctl: - handle the ioctls associated with tracing
710 * @bdev: the block device
711 * @cmd: the ioctl cmd
712 * @arg: the argument data, if any
713 *
714 **/
715int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
716{
717 struct request_queue *q;
718 int ret, start = 0;
719 char b[BDEVNAME_SIZE];
720
721 q = bdev_get_queue(bdev);
722 if (!q)
723 return -ENXIO;
724
725 mutex_lock(&q->debugfs_mutex);
726
727 switch (cmd) {
728 case BLKTRACESETUP:
729 bdevname(bdev, b);
730 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
731 break;
732#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
733 case BLKTRACESETUP32:
734 bdevname(bdev, b);
735 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
736 break;
737#endif
738 case BLKTRACESTART:
739 start = 1;
740 fallthrough;
741 case BLKTRACESTOP:
742 ret = __blk_trace_startstop(q, start);
743 break;
744 case BLKTRACETEARDOWN:
745 ret = __blk_trace_remove(q);
746 break;
747 default:
748 ret = -ENOTTY;
749 break;
750 }
751
752 mutex_unlock(&q->debugfs_mutex);
753 return ret;
754}
755
756/**
757 * blk_trace_shutdown: - stop and cleanup trace structures
758 * @q: the request queue associated with the device
759 *
760 **/
761void blk_trace_shutdown(struct request_queue *q)
762{
763 mutex_lock(&q->debugfs_mutex);
764 if (rcu_dereference_protected(q->blk_trace,
765 lockdep_is_held(&q->debugfs_mutex))) {
766 __blk_trace_startstop(q, 0);
767 __blk_trace_remove(q);
768 }
769
770 mutex_unlock(&q->debugfs_mutex);
771}
772
773#ifdef CONFIG_BLK_CGROUP
774static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
775{
776 struct blk_trace *bt;
777
778 /* We don't use the 'bt' value here except as an optimization... */
779 bt = rcu_dereference_protected(q->blk_trace, 1);
780 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
781 return 0;
782
783 if (!bio->bi_blkg)
784 return 0;
785 return cgroup_id(bio_blkcg(bio)->css.cgroup);
786}
787#else
788static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
789{
790 return 0;
791}
792#endif
793
794static u64
795blk_trace_request_get_cgid(struct request *rq)
796{
797 if (!rq->bio)
798 return 0;
799 /* Use the first bio */
800 return blk_trace_bio_get_cgid(rq->q, rq->bio);
801}
802
803/*
804 * blktrace probes
805 */
806
807/**
808 * blk_add_trace_rq - Add a trace for a request oriented action
809 * @rq: the source request
810 * @error: return status to log
811 * @nr_bytes: number of completed bytes
812 * @what: the action
813 * @cgid: the cgroup info
814 *
815 * Description:
816 * Records an action against a request. Will log the bio offset + size.
817 *
818 **/
819static void blk_add_trace_rq(struct request *rq, int error,
820 unsigned int nr_bytes, u32 what, u64 cgid)
821{
822 struct blk_trace *bt;
823
824 rcu_read_lock();
825 bt = rcu_dereference(rq->q->blk_trace);
826 if (likely(!bt)) {
827 rcu_read_unlock();
828 return;
829 }
830
831 if (blk_rq_is_passthrough(rq))
832 what |= BLK_TC_ACT(BLK_TC_PC);
833 else
834 what |= BLK_TC_ACT(BLK_TC_FS);
835
836 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
837 rq->cmd_flags, what, error, 0, NULL, cgid);
838 rcu_read_unlock();
839}
840
841static void blk_add_trace_rq_insert(void *ignore, struct request *rq)
842{
843 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
844 blk_trace_request_get_cgid(rq));
845}
846
847static void blk_add_trace_rq_issue(void *ignore, struct request *rq)
848{
849 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
850 blk_trace_request_get_cgid(rq));
851}
852
853static void blk_add_trace_rq_merge(void *ignore, struct request *rq)
854{
855 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
856 blk_trace_request_get_cgid(rq));
857}
858
859static void blk_add_trace_rq_requeue(void *ignore, struct request *rq)
860{
861 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
862 blk_trace_request_get_cgid(rq));
863}
864
865static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
866 int error, unsigned int nr_bytes)
867{
868 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
869 blk_trace_request_get_cgid(rq));
870}
871
872/**
873 * blk_add_trace_bio - Add a trace for a bio oriented action
874 * @q: queue the io is for
875 * @bio: the source bio
876 * @what: the action
877 * @error: error, if any
878 *
879 * Description:
880 * Records an action against a bio. Will log the bio offset + size.
881 *
882 **/
883static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
884 u32 what, int error)
885{
886 struct blk_trace *bt;
887
888 rcu_read_lock();
889 bt = rcu_dereference(q->blk_trace);
890 if (likely(!bt)) {
891 rcu_read_unlock();
892 return;
893 }
894
895 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
896 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
897 blk_trace_bio_get_cgid(q, bio));
898 rcu_read_unlock();
899}
900
901static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio)
902{
903 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0);
904}
905
906static void blk_add_trace_bio_complete(void *ignore,
907 struct request_queue *q, struct bio *bio)
908{
909 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
910 blk_status_to_errno(bio->bi_status));
911}
912
913static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio)
914{
915 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE,
916 0);
917}
918
919static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio)
920{
921 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE,
922 0);
923}
924
925static void blk_add_trace_bio_queue(void *ignore, struct bio *bio)
926{
927 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0);
928}
929
930static void blk_add_trace_getrq(void *ignore, struct bio *bio)
931{
932 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0);
933}
934
935static void blk_add_trace_plug(void *ignore, struct request_queue *q)
936{
937 struct blk_trace *bt;
938
939 rcu_read_lock();
940 bt = rcu_dereference(q->blk_trace);
941 if (bt)
942 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
943 rcu_read_unlock();
944}
945
946static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
947 unsigned int depth, bool explicit)
948{
949 struct blk_trace *bt;
950
951 rcu_read_lock();
952 bt = rcu_dereference(q->blk_trace);
953 if (bt) {
954 __be64 rpdu = cpu_to_be64(depth);
955 u32 what;
956
957 if (explicit)
958 what = BLK_TA_UNPLUG_IO;
959 else
960 what = BLK_TA_UNPLUG_TIMER;
961
962 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
963 }
964 rcu_read_unlock();
965}
966
967static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
968{
969 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
970 struct blk_trace *bt;
971
972 rcu_read_lock();
973 bt = rcu_dereference(q->blk_trace);
974 if (bt) {
975 __be64 rpdu = cpu_to_be64(pdu);
976
977 __blk_add_trace(bt, bio->bi_iter.bi_sector,
978 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
979 BLK_TA_SPLIT,
980 blk_status_to_errno(bio->bi_status),
981 sizeof(rpdu), &rpdu,
982 blk_trace_bio_get_cgid(q, bio));
983 }
984 rcu_read_unlock();
985}
986
987/**
988 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
989 * @ignore: trace callback data parameter (not used)
990 * @bio: the source bio
991 * @dev: source device
992 * @from: source sector
993 *
994 * Called after a bio is remapped to a different device and/or sector.
995 **/
996static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev,
997 sector_t from)
998{
999 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
1000 struct blk_trace *bt;
1001 struct blk_io_trace_remap r;
1002
1003 rcu_read_lock();
1004 bt = rcu_dereference(q->blk_trace);
1005 if (likely(!bt)) {
1006 rcu_read_unlock();
1007 return;
1008 }
1009
1010 r.device_from = cpu_to_be32(dev);
1011 r.device_to = cpu_to_be32(bio_dev(bio));
1012 r.sector_from = cpu_to_be64(from);
1013
1014 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1015 bio_op(bio), bio->bi_opf, BLK_TA_REMAP,
1016 blk_status_to_errno(bio->bi_status),
1017 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1018 rcu_read_unlock();
1019}
1020
1021/**
1022 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1023 * @ignore: trace callback data parameter (not used)
1024 * @rq: the source request
1025 * @dev: target device
1026 * @from: source sector
1027 *
1028 * Description:
1029 * Device mapper remaps request to other devices.
1030 * Add a trace for that action.
1031 *
1032 **/
1033static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev,
1034 sector_t from)
1035{
1036 struct blk_trace *bt;
1037 struct blk_io_trace_remap r;
1038
1039 rcu_read_lock();
1040 bt = rcu_dereference(rq->q->blk_trace);
1041 if (likely(!bt)) {
1042 rcu_read_unlock();
1043 return;
1044 }
1045
1046 r.device_from = cpu_to_be32(dev);
1047 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1048 r.sector_from = cpu_to_be64(from);
1049
1050 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1051 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1052 sizeof(r), &r, blk_trace_request_get_cgid(rq));
1053 rcu_read_unlock();
1054}
1055
1056/**
1057 * blk_add_driver_data - Add binary message with driver-specific data
1058 * @rq: io request
1059 * @data: driver-specific data
1060 * @len: length of driver-specific data
1061 *
1062 * Description:
1063 * Some drivers might want to write driver-specific data per request.
1064 *
1065 **/
1066void blk_add_driver_data(struct request *rq, void *data, size_t len)
1067{
1068 struct blk_trace *bt;
1069
1070 rcu_read_lock();
1071 bt = rcu_dereference(rq->q->blk_trace);
1072 if (likely(!bt)) {
1073 rcu_read_unlock();
1074 return;
1075 }
1076
1077 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1078 BLK_TA_DRV_DATA, 0, len, data,
1079 blk_trace_request_get_cgid(rq));
1080 rcu_read_unlock();
1081}
1082EXPORT_SYMBOL_GPL(blk_add_driver_data);
1083
1084static void blk_register_tracepoints(void)
1085{
1086 int ret;
1087
1088 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1089 WARN_ON(ret);
1090 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1091 WARN_ON(ret);
1092 ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1093 WARN_ON(ret);
1094 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1095 WARN_ON(ret);
1096 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1097 WARN_ON(ret);
1098 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1099 WARN_ON(ret);
1100 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1101 WARN_ON(ret);
1102 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1103 WARN_ON(ret);
1104 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1105 WARN_ON(ret);
1106 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1107 WARN_ON(ret);
1108 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1109 WARN_ON(ret);
1110 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1111 WARN_ON(ret);
1112 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1113 WARN_ON(ret);
1114 ret = register_trace_block_split(blk_add_trace_split, NULL);
1115 WARN_ON(ret);
1116 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1117 WARN_ON(ret);
1118 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1119 WARN_ON(ret);
1120}
1121
1122static void blk_unregister_tracepoints(void)
1123{
1124 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1125 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1126 unregister_trace_block_split(blk_add_trace_split, NULL);
1127 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1128 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1129 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1130 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1131 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1132 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1133 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1134 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1135 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1136 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1137 unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1138 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1139 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1140
1141 tracepoint_synchronize_unregister();
1142}
1143
1144/*
1145 * struct blk_io_tracer formatting routines
1146 */
1147
1148static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1149{
1150 int i = 0;
1151 int tc = t->action >> BLK_TC_SHIFT;
1152
1153 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1154 rwbs[i++] = 'N';
1155 goto out;
1156 }
1157
1158 if (tc & BLK_TC_FLUSH)
1159 rwbs[i++] = 'F';
1160
1161 if (tc & BLK_TC_DISCARD)
1162 rwbs[i++] = 'D';
1163 else if (tc & BLK_TC_WRITE)
1164 rwbs[i++] = 'W';
1165 else if (t->bytes)
1166 rwbs[i++] = 'R';
1167 else
1168 rwbs[i++] = 'N';
1169
1170 if (tc & BLK_TC_FUA)
1171 rwbs[i++] = 'F';
1172 if (tc & BLK_TC_AHEAD)
1173 rwbs[i++] = 'A';
1174 if (tc & BLK_TC_SYNC)
1175 rwbs[i++] = 'S';
1176 if (tc & BLK_TC_META)
1177 rwbs[i++] = 'M';
1178out:
1179 rwbs[i] = '\0';
1180}
1181
1182static inline
1183const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1184{
1185 return (const struct blk_io_trace *)ent;
1186}
1187
1188static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1189{
1190 return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
1191}
1192
1193static inline u64 t_cgid(const struct trace_entry *ent)
1194{
1195 return *(u64 *)(te_blk_io_trace(ent) + 1);
1196}
1197
1198static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1199{
1200 return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
1201}
1202
1203static inline u32 t_action(const struct trace_entry *ent)
1204{
1205 return te_blk_io_trace(ent)->action;
1206}
1207
1208static inline u32 t_bytes(const struct trace_entry *ent)
1209{
1210 return te_blk_io_trace(ent)->bytes;
1211}
1212
1213static inline u32 t_sec(const struct trace_entry *ent)
1214{
1215 return te_blk_io_trace(ent)->bytes >> 9;
1216}
1217
1218static inline unsigned long long t_sector(const struct trace_entry *ent)
1219{
1220 return te_blk_io_trace(ent)->sector;
1221}
1222
1223static inline __u16 t_error(const struct trace_entry *ent)
1224{
1225 return te_blk_io_trace(ent)->error;
1226}
1227
1228static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1229{
1230 const __be64 *val = pdu_start(ent, has_cg);
1231 return be64_to_cpu(*val);
1232}
1233
1234typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1235 bool has_cg);
1236
1237static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1238 bool has_cg)
1239{
1240 char rwbs[RWBS_LEN];
1241 unsigned long long ts = iter->ts;
1242 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1243 unsigned secs = (unsigned long)ts;
1244 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1245
1246 fill_rwbs(rwbs, t);
1247
1248 trace_seq_printf(&iter->seq,
1249 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1250 MAJOR(t->device), MINOR(t->device), iter->cpu,
1251 secs, nsec_rem, iter->ent->pid, act, rwbs);
1252}
1253
1254static void blk_log_action(struct trace_iterator *iter, const char *act,
1255 bool has_cg)
1256{
1257 char rwbs[RWBS_LEN];
1258 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1259
1260 fill_rwbs(rwbs, t);
1261 if (has_cg) {
1262 u64 id = t_cgid(iter->ent);
1263
1264 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1265 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1266
1267 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1268 sizeof(blkcg_name_buf));
1269 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1270 MAJOR(t->device), MINOR(t->device),
1271 blkcg_name_buf, act, rwbs);
1272 } else {
1273 /*
1274 * The cgid portion used to be "INO,GEN". Userland
1275 * builds a FILEID_INO32_GEN fid out of them and
1276 * opens the cgroup using open_by_handle_at(2).
1277 * While 32bit ino setups are still the same, 64bit
1278 * ones now use the 64bit ino as the whole ID and
1279 * no longer use generation.
1280 *
1281 * Regardless of the content, always output
1282 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
1283 * be mapped back to @id on both 64 and 32bit ino
1284 * setups. See __kernfs_fh_to_dentry().
1285 */
1286 trace_seq_printf(&iter->seq,
1287 "%3d,%-3d %llx,%-llx %2s %3s ",
1288 MAJOR(t->device), MINOR(t->device),
1289 id & U32_MAX, id >> 32, act, rwbs);
1290 }
1291 } else
1292 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1293 MAJOR(t->device), MINOR(t->device), act, rwbs);
1294}
1295
1296static void blk_log_dump_pdu(struct trace_seq *s,
1297 const struct trace_entry *ent, bool has_cg)
1298{
1299 const unsigned char *pdu_buf;
1300 int pdu_len;
1301 int i, end;
1302
1303 pdu_buf = pdu_start(ent, has_cg);
1304 pdu_len = pdu_real_len(ent, has_cg);
1305
1306 if (!pdu_len)
1307 return;
1308
1309 /* find the last zero that needs to be printed */
1310 for (end = pdu_len - 1; end >= 0; end--)
1311 if (pdu_buf[end])
1312 break;
1313 end++;
1314
1315 trace_seq_putc(s, '(');
1316
1317 for (i = 0; i < pdu_len; i++) {
1318
1319 trace_seq_printf(s, "%s%02x",
1320 i == 0 ? "" : " ", pdu_buf[i]);
1321
1322 /*
1323 * stop when the rest is just zeros and indicate so
1324 * with a ".." appended
1325 */
1326 if (i == end && end != pdu_len - 1) {
1327 trace_seq_puts(s, " ..) ");
1328 return;
1329 }
1330 }
1331
1332 trace_seq_puts(s, ") ");
1333}
1334
1335static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1336{
1337 char cmd[TASK_COMM_LEN];
1338
1339 trace_find_cmdline(ent->pid, cmd);
1340
1341 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1342 trace_seq_printf(s, "%u ", t_bytes(ent));
1343 blk_log_dump_pdu(s, ent, has_cg);
1344 trace_seq_printf(s, "[%s]\n", cmd);
1345 } else {
1346 if (t_sec(ent))
1347 trace_seq_printf(s, "%llu + %u [%s]\n",
1348 t_sector(ent), t_sec(ent), cmd);
1349 else
1350 trace_seq_printf(s, "[%s]\n", cmd);
1351 }
1352}
1353
1354static void blk_log_with_error(struct trace_seq *s,
1355 const struct trace_entry *ent, bool has_cg)
1356{
1357 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1358 blk_log_dump_pdu(s, ent, has_cg);
1359 trace_seq_printf(s, "[%d]\n", t_error(ent));
1360 } else {
1361 if (t_sec(ent))
1362 trace_seq_printf(s, "%llu + %u [%d]\n",
1363 t_sector(ent),
1364 t_sec(ent), t_error(ent));
1365 else
1366 trace_seq_printf(s, "%llu [%d]\n",
1367 t_sector(ent), t_error(ent));
1368 }
1369}
1370
1371static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1372{
1373 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1374
1375 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1376 t_sector(ent), t_sec(ent),
1377 MAJOR(be32_to_cpu(__r->device_from)),
1378 MINOR(be32_to_cpu(__r->device_from)),
1379 be64_to_cpu(__r->sector_from));
1380}
1381
1382static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1383{
1384 char cmd[TASK_COMM_LEN];
1385
1386 trace_find_cmdline(ent->pid, cmd);
1387
1388 trace_seq_printf(s, "[%s]\n", cmd);
1389}
1390
1391static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1392{
1393 char cmd[TASK_COMM_LEN];
1394
1395 trace_find_cmdline(ent->pid, cmd);
1396
1397 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1398}
1399
1400static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1401{
1402 char cmd[TASK_COMM_LEN];
1403
1404 trace_find_cmdline(ent->pid, cmd);
1405
1406 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1407 get_pdu_int(ent, has_cg), cmd);
1408}
1409
1410static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1411 bool has_cg)
1412{
1413
1414 trace_seq_putmem(s, pdu_start(ent, has_cg),
1415 pdu_real_len(ent, has_cg));
1416 trace_seq_putc(s, '\n');
1417}
1418
1419/*
1420 * struct tracer operations
1421 */
1422
1423static void blk_tracer_print_header(struct seq_file *m)
1424{
1425 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1426 return;
1427 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1428 "# | | | | | |\n");
1429}
1430
1431static void blk_tracer_start(struct trace_array *tr)
1432{
1433 blk_tracer_enabled = true;
1434}
1435
1436static int blk_tracer_init(struct trace_array *tr)
1437{
1438 blk_tr = tr;
1439 blk_tracer_start(tr);
1440 return 0;
1441}
1442
1443static void blk_tracer_stop(struct trace_array *tr)
1444{
1445 blk_tracer_enabled = false;
1446}
1447
1448static void blk_tracer_reset(struct trace_array *tr)
1449{
1450 blk_tracer_stop(tr);
1451}
1452
1453static const struct {
1454 const char *act[2];
1455 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1456 bool has_cg);
1457} what2act[] = {
1458 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1459 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1460 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1461 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1462 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1463 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1464 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1465 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1466 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1467 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1468 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1469 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1470 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1471 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1472 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1473};
1474
1475static enum print_line_t print_one_line(struct trace_iterator *iter,
1476 bool classic)
1477{
1478 struct trace_array *tr = iter->tr;
1479 struct trace_seq *s = &iter->seq;
1480 const struct blk_io_trace *t;
1481 u16 what;
1482 bool long_act;
1483 blk_log_action_t *log_action;
1484 bool has_cg;
1485
1486 t = te_blk_io_trace(iter->ent);
1487 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1488 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1489 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1490 has_cg = t->action & __BLK_TA_CGROUP;
1491
1492 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1493 log_action(iter, long_act ? "message" : "m", has_cg);
1494 blk_log_msg(s, iter->ent, has_cg);
1495 return trace_handle_return(s);
1496 }
1497
1498 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1499 trace_seq_printf(s, "Unknown action %x\n", what);
1500 else {
1501 log_action(iter, what2act[what].act[long_act], has_cg);
1502 what2act[what].print(s, iter->ent, has_cg);
1503 }
1504
1505 return trace_handle_return(s);
1506}
1507
1508static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1509 int flags, struct trace_event *event)
1510{
1511 return print_one_line(iter, false);
1512}
1513
1514static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1515{
1516 struct trace_seq *s = &iter->seq;
1517 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1518 const int offset = offsetof(struct blk_io_trace, sector);
1519 struct blk_io_trace old = {
1520 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1521 .time = iter->ts,
1522 };
1523
1524 trace_seq_putmem(s, &old, offset);
1525 trace_seq_putmem(s, &t->sector,
1526 sizeof(old) - offset + t->pdu_len);
1527}
1528
1529static enum print_line_t
1530blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1531 struct trace_event *event)
1532{
1533 blk_trace_synthesize_old_trace(iter);
1534
1535 return trace_handle_return(&iter->seq);
1536}
1537
1538static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1539{
1540 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1541 return TRACE_TYPE_UNHANDLED;
1542
1543 return print_one_line(iter, true);
1544}
1545
1546static int
1547blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1548{
1549 /* don't output context-info for blk_classic output */
1550 if (bit == TRACE_BLK_OPT_CLASSIC) {
1551 if (set)
1552 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1553 else
1554 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1555 }
1556 return 0;
1557}
1558
1559static struct tracer blk_tracer __read_mostly = {
1560 .name = "blk",
1561 .init = blk_tracer_init,
1562 .reset = blk_tracer_reset,
1563 .start = blk_tracer_start,
1564 .stop = blk_tracer_stop,
1565 .print_header = blk_tracer_print_header,
1566 .print_line = blk_tracer_print_line,
1567 .flags = &blk_tracer_flags,
1568 .set_flag = blk_tracer_set_flag,
1569};
1570
1571static struct trace_event_functions trace_blk_event_funcs = {
1572 .trace = blk_trace_event_print,
1573 .binary = blk_trace_event_print_binary,
1574};
1575
1576static struct trace_event trace_blk_event = {
1577 .type = TRACE_BLK,
1578 .funcs = &trace_blk_event_funcs,
1579};
1580
1581static int __init init_blk_tracer(void)
1582{
1583 if (!register_trace_event(&trace_blk_event)) {
1584 pr_warn("Warning: could not register block events\n");
1585 return 1;
1586 }
1587
1588 if (register_tracer(&blk_tracer) != 0) {
1589 pr_warn("Warning: could not register the block tracer\n");
1590 unregister_trace_event(&trace_blk_event);
1591 return 1;
1592 }
1593
1594 return 0;
1595}
1596
1597device_initcall(init_blk_tracer);
1598
1599static int blk_trace_remove_queue(struct request_queue *q)
1600{
1601 struct blk_trace *bt;
1602
1603 bt = rcu_replace_pointer(q->blk_trace, NULL,
1604 lockdep_is_held(&q->debugfs_mutex));
1605 if (bt == NULL)
1606 return -EINVAL;
1607
1608 if (bt->trace_state == Blktrace_running) {
1609 bt->trace_state = Blktrace_stopped;
1610 spin_lock_irq(&running_trace_lock);
1611 list_del_init(&bt->running_list);
1612 spin_unlock_irq(&running_trace_lock);
1613 relay_flush(bt->rchan);
1614 }
1615
1616 put_probe_ref();
1617 synchronize_rcu();
1618 blk_trace_free(bt);
1619 return 0;
1620}
1621
1622/*
1623 * Setup everything required to start tracing
1624 */
1625static int blk_trace_setup_queue(struct request_queue *q,
1626 struct block_device *bdev)
1627{
1628 struct blk_trace *bt = NULL;
1629 int ret = -ENOMEM;
1630
1631 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1632 if (!bt)
1633 return -ENOMEM;
1634
1635 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1636 if (!bt->msg_data)
1637 goto free_bt;
1638
1639 bt->dev = bdev->bd_dev;
1640 bt->act_mask = (u16)-1;
1641
1642 blk_trace_setup_lba(bt, bdev);
1643
1644 rcu_assign_pointer(q->blk_trace, bt);
1645 get_probe_ref();
1646 return 0;
1647
1648free_bt:
1649 blk_trace_free(bt);
1650 return ret;
1651}
1652
1653/*
1654 * sysfs interface to enable and configure tracing
1655 */
1656
1657static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1658 struct device_attribute *attr,
1659 char *buf);
1660static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1661 struct device_attribute *attr,
1662 const char *buf, size_t count);
1663#define BLK_TRACE_DEVICE_ATTR(_name) \
1664 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1665 sysfs_blk_trace_attr_show, \
1666 sysfs_blk_trace_attr_store)
1667
1668static BLK_TRACE_DEVICE_ATTR(enable);
1669static BLK_TRACE_DEVICE_ATTR(act_mask);
1670static BLK_TRACE_DEVICE_ATTR(pid);
1671static BLK_TRACE_DEVICE_ATTR(start_lba);
1672static BLK_TRACE_DEVICE_ATTR(end_lba);
1673
1674static struct attribute *blk_trace_attrs[] = {
1675 &dev_attr_enable.attr,
1676 &dev_attr_act_mask.attr,
1677 &dev_attr_pid.attr,
1678 &dev_attr_start_lba.attr,
1679 &dev_attr_end_lba.attr,
1680 NULL
1681};
1682
1683struct attribute_group blk_trace_attr_group = {
1684 .name = "trace",
1685 .attrs = blk_trace_attrs,
1686};
1687
1688static const struct {
1689 int mask;
1690 const char *str;
1691} mask_maps[] = {
1692 { BLK_TC_READ, "read" },
1693 { BLK_TC_WRITE, "write" },
1694 { BLK_TC_FLUSH, "flush" },
1695 { BLK_TC_SYNC, "sync" },
1696 { BLK_TC_QUEUE, "queue" },
1697 { BLK_TC_REQUEUE, "requeue" },
1698 { BLK_TC_ISSUE, "issue" },
1699 { BLK_TC_COMPLETE, "complete" },
1700 { BLK_TC_FS, "fs" },
1701 { BLK_TC_PC, "pc" },
1702 { BLK_TC_NOTIFY, "notify" },
1703 { BLK_TC_AHEAD, "ahead" },
1704 { BLK_TC_META, "meta" },
1705 { BLK_TC_DISCARD, "discard" },
1706 { BLK_TC_DRV_DATA, "drv_data" },
1707 { BLK_TC_FUA, "fua" },
1708};
1709
1710static int blk_trace_str2mask(const char *str)
1711{
1712 int i;
1713 int mask = 0;
1714 char *buf, *s, *token;
1715
1716 buf = kstrdup(str, GFP_KERNEL);
1717 if (buf == NULL)
1718 return -ENOMEM;
1719 s = strstrip(buf);
1720
1721 while (1) {
1722 token = strsep(&s, ",");
1723 if (token == NULL)
1724 break;
1725
1726 if (*token == '\0')
1727 continue;
1728
1729 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1730 if (strcasecmp(token, mask_maps[i].str) == 0) {
1731 mask |= mask_maps[i].mask;
1732 break;
1733 }
1734 }
1735 if (i == ARRAY_SIZE(mask_maps)) {
1736 mask = -EINVAL;
1737 break;
1738 }
1739 }
1740 kfree(buf);
1741
1742 return mask;
1743}
1744
1745static ssize_t blk_trace_mask2str(char *buf, int mask)
1746{
1747 int i;
1748 char *p = buf;
1749
1750 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1751 if (mask & mask_maps[i].mask) {
1752 p += sprintf(p, "%s%s",
1753 (p == buf) ? "" : ",", mask_maps[i].str);
1754 }
1755 }
1756 *p++ = '\n';
1757
1758 return p - buf;
1759}
1760
1761static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1762 struct device_attribute *attr,
1763 char *buf)
1764{
1765 struct block_device *bdev = dev_to_bdev(dev);
1766 struct request_queue *q = bdev_get_queue(bdev);
1767 struct blk_trace *bt;
1768 ssize_t ret = -ENXIO;
1769
1770 mutex_lock(&q->debugfs_mutex);
1771
1772 bt = rcu_dereference_protected(q->blk_trace,
1773 lockdep_is_held(&q->debugfs_mutex));
1774 if (attr == &dev_attr_enable) {
1775 ret = sprintf(buf, "%u\n", !!bt);
1776 goto out_unlock_bdev;
1777 }
1778
1779 if (bt == NULL)
1780 ret = sprintf(buf, "disabled\n");
1781 else if (attr == &dev_attr_act_mask)
1782 ret = blk_trace_mask2str(buf, bt->act_mask);
1783 else if (attr == &dev_attr_pid)
1784 ret = sprintf(buf, "%u\n", bt->pid);
1785 else if (attr == &dev_attr_start_lba)
1786 ret = sprintf(buf, "%llu\n", bt->start_lba);
1787 else if (attr == &dev_attr_end_lba)
1788 ret = sprintf(buf, "%llu\n", bt->end_lba);
1789
1790out_unlock_bdev:
1791 mutex_unlock(&q->debugfs_mutex);
1792 return ret;
1793}
1794
1795static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1796 struct device_attribute *attr,
1797 const char *buf, size_t count)
1798{
1799 struct block_device *bdev = dev_to_bdev(dev);
1800 struct request_queue *q = bdev_get_queue(bdev);
1801 struct blk_trace *bt;
1802 u64 value;
1803 ssize_t ret = -EINVAL;
1804
1805 if (count == 0)
1806 goto out;
1807
1808 if (attr == &dev_attr_act_mask) {
1809 if (kstrtoull(buf, 0, &value)) {
1810 /* Assume it is a list of trace category names */
1811 ret = blk_trace_str2mask(buf);
1812 if (ret < 0)
1813 goto out;
1814 value = ret;
1815 }
1816 } else {
1817 if (kstrtoull(buf, 0, &value))
1818 goto out;
1819 }
1820
1821 mutex_lock(&q->debugfs_mutex);
1822
1823 bt = rcu_dereference_protected(q->blk_trace,
1824 lockdep_is_held(&q->debugfs_mutex));
1825 if (attr == &dev_attr_enable) {
1826 if (!!value == !!bt) {
1827 ret = 0;
1828 goto out_unlock_bdev;
1829 }
1830 if (value)
1831 ret = blk_trace_setup_queue(q, bdev);
1832 else
1833 ret = blk_trace_remove_queue(q);
1834 goto out_unlock_bdev;
1835 }
1836
1837 ret = 0;
1838 if (bt == NULL) {
1839 ret = blk_trace_setup_queue(q, bdev);
1840 bt = rcu_dereference_protected(q->blk_trace,
1841 lockdep_is_held(&q->debugfs_mutex));
1842 }
1843
1844 if (ret == 0) {
1845 if (attr == &dev_attr_act_mask)
1846 bt->act_mask = value;
1847 else if (attr == &dev_attr_pid)
1848 bt->pid = value;
1849 else if (attr == &dev_attr_start_lba)
1850 bt->start_lba = value;
1851 else if (attr == &dev_attr_end_lba)
1852 bt->end_lba = value;
1853 }
1854
1855out_unlock_bdev:
1856 mutex_unlock(&q->debugfs_mutex);
1857out:
1858 return ret ? ret : count;
1859}
1860
1861int blk_trace_init_sysfs(struct device *dev)
1862{
1863 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1864}
1865
1866void blk_trace_remove_sysfs(struct device *dev)
1867{
1868 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1869}
1870
1871#endif /* CONFIG_BLK_DEV_IO_TRACE */
1872
1873#ifdef CONFIG_EVENT_TRACING
1874
1875/**
1876 * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string.
1877 * @rwbs: buffer to be filled
1878 * @op: REQ_OP_XXX for the tracepoint
1879 *
1880 * Description:
1881 * Maps the REQ_OP_XXX to character and fills the buffer provided by the
1882 * caller with resulting string.
1883 *
1884 **/
1885void blk_fill_rwbs(char *rwbs, unsigned int op)
1886{
1887 int i = 0;
1888
1889 if (op & REQ_PREFLUSH)
1890 rwbs[i++] = 'F';
1891
1892 switch (op & REQ_OP_MASK) {
1893 case REQ_OP_WRITE:
1894 case REQ_OP_WRITE_SAME:
1895 rwbs[i++] = 'W';
1896 break;
1897 case REQ_OP_DISCARD:
1898 rwbs[i++] = 'D';
1899 break;
1900 case REQ_OP_SECURE_ERASE:
1901 rwbs[i++] = 'D';
1902 rwbs[i++] = 'E';
1903 break;
1904 case REQ_OP_FLUSH:
1905 rwbs[i++] = 'F';
1906 break;
1907 case REQ_OP_READ:
1908 rwbs[i++] = 'R';
1909 break;
1910 default:
1911 rwbs[i++] = 'N';
1912 }
1913
1914 if (op & REQ_FUA)
1915 rwbs[i++] = 'F';
1916 if (op & REQ_RAHEAD)
1917 rwbs[i++] = 'A';
1918 if (op & REQ_SYNC)
1919 rwbs[i++] = 'S';
1920 if (op & REQ_META)
1921 rwbs[i++] = 'M';
1922
1923 rwbs[i] = '\0';
1924}
1925EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1926
1927#endif /* CONFIG_EVENT_TRACING */
1928