Loading...
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(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(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 = kmalloc(count + 1, GFP_KERNEL);
353 if (msg == NULL)
354 return -ENOMEM;
355
356 if (copy_from_user(msg, buffer, count)) {
357 kfree(msg);
358 return -EFAULT;
359 }
360
361 msg[count] = '\0';
362 bt = filp->private_data;
363 __trace_note_message(bt, "%s", msg);
364 kfree(msg);
365
366 return count;
367}
368
369static const struct file_operations blk_msg_fops = {
370 .owner = THIS_MODULE,
371 .open = simple_open,
372 .write = blk_msg_write,
373 .llseek = noop_llseek,
374};
375
376/*
377 * Keep track of how many times we encountered a full subbuffer, to aid
378 * the user space app in telling how many lost events there were.
379 */
380static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
381 void *prev_subbuf, size_t prev_padding)
382{
383 struct blk_trace *bt;
384
385 if (!relay_buf_full(buf))
386 return 1;
387
388 bt = buf->chan->private_data;
389 atomic_inc(&bt->dropped);
390 return 0;
391}
392
393static int blk_remove_buf_file_callback(struct dentry *dentry)
394{
395 debugfs_remove(dentry);
396
397 return 0;
398}
399
400static struct dentry *blk_create_buf_file_callback(const char *filename,
401 struct dentry *parent,
402 umode_t mode,
403 struct rchan_buf *buf,
404 int *is_global)
405{
406 return debugfs_create_file(filename, mode, parent, buf,
407 &relay_file_operations);
408}
409
410static struct rchan_callbacks blk_relay_callbacks = {
411 .subbuf_start = blk_subbuf_start_callback,
412 .create_buf_file = blk_create_buf_file_callback,
413 .remove_buf_file = blk_remove_buf_file_callback,
414};
415
416static void blk_trace_setup_lba(struct blk_trace *bt,
417 struct block_device *bdev)
418{
419 struct hd_struct *part = NULL;
420
421 if (bdev)
422 part = bdev->bd_part;
423
424 if (part) {
425 bt->start_lba = part->start_sect;
426 bt->end_lba = part->start_sect + part->nr_sects;
427 } else {
428 bt->start_lba = 0;
429 bt->end_lba = -1ULL;
430 }
431}
432
433/*
434 * Setup everything required to start tracing
435 */
436int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
437 struct block_device *bdev,
438 struct blk_user_trace_setup *buts)
439{
440 struct blk_trace *old_bt, *bt = NULL;
441 struct dentry *dir = NULL;
442 int ret, i;
443
444 if (!buts->buf_size || !buts->buf_nr)
445 return -EINVAL;
446
447 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
448 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
449
450 /*
451 * some device names have larger paths - convert the slashes
452 * to underscores for this to work as expected
453 */
454 for (i = 0; i < strlen(buts->name); i++)
455 if (buts->name[i] == '/')
456 buts->name[i] = '_';
457
458 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
459 if (!bt)
460 return -ENOMEM;
461
462 ret = -ENOMEM;
463 bt->sequence = alloc_percpu(unsigned long);
464 if (!bt->sequence)
465 goto err;
466
467 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
468 if (!bt->msg_data)
469 goto err;
470
471 ret = -ENOENT;
472
473 mutex_lock(&blk_tree_mutex);
474 if (!blk_tree_root) {
475 blk_tree_root = debugfs_create_dir("block", NULL);
476 if (!blk_tree_root) {
477 mutex_unlock(&blk_tree_mutex);
478 goto err;
479 }
480 }
481 mutex_unlock(&blk_tree_mutex);
482
483 dir = debugfs_create_dir(buts->name, blk_tree_root);
484
485 if (!dir)
486 goto err;
487
488 bt->dir = dir;
489 bt->dev = dev;
490 atomic_set(&bt->dropped, 0);
491 INIT_LIST_HEAD(&bt->running_list);
492
493 ret = -EIO;
494 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
495 &blk_dropped_fops);
496 if (!bt->dropped_file)
497 goto err;
498
499 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
500 if (!bt->msg_file)
501 goto err;
502
503 bt->rchan = relay_open("trace", dir, buts->buf_size,
504 buts->buf_nr, &blk_relay_callbacks, bt);
505 if (!bt->rchan)
506 goto err;
507
508 bt->act_mask = buts->act_mask;
509 if (!bt->act_mask)
510 bt->act_mask = (u16) -1;
511
512 blk_trace_setup_lba(bt, bdev);
513
514 /* overwrite with user settings */
515 if (buts->start_lba)
516 bt->start_lba = buts->start_lba;
517 if (buts->end_lba)
518 bt->end_lba = buts->end_lba;
519
520 bt->pid = buts->pid;
521 bt->trace_state = Blktrace_setup;
522
523 ret = -EBUSY;
524 old_bt = xchg(&q->blk_trace, bt);
525 if (old_bt) {
526 (void) xchg(&q->blk_trace, old_bt);
527 goto err;
528 }
529
530 if (atomic_inc_return(&blk_probes_ref) == 1)
531 blk_register_tracepoints();
532
533 return 0;
534err:
535 blk_trace_free(bt);
536 return ret;
537}
538
539int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
540 struct block_device *bdev,
541 char __user *arg)
542{
543 struct blk_user_trace_setup buts;
544 int ret;
545
546 ret = copy_from_user(&buts, arg, sizeof(buts));
547 if (ret)
548 return -EFAULT;
549
550 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
551 if (ret)
552 return ret;
553
554 if (copy_to_user(arg, &buts, sizeof(buts))) {
555 blk_trace_remove(q);
556 return -EFAULT;
557 }
558 return 0;
559}
560EXPORT_SYMBOL_GPL(blk_trace_setup);
561
562#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
563static int compat_blk_trace_setup(struct request_queue *q, char *name,
564 dev_t dev, struct block_device *bdev,
565 char __user *arg)
566{
567 struct blk_user_trace_setup buts;
568 struct compat_blk_user_trace_setup cbuts;
569 int ret;
570
571 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
572 return -EFAULT;
573
574 buts = (struct blk_user_trace_setup) {
575 .act_mask = cbuts.act_mask,
576 .buf_size = cbuts.buf_size,
577 .buf_nr = cbuts.buf_nr,
578 .start_lba = cbuts.start_lba,
579 .end_lba = cbuts.end_lba,
580 .pid = cbuts.pid,
581 };
582
583 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
584 if (ret)
585 return ret;
586
587 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
588 blk_trace_remove(q);
589 return -EFAULT;
590 }
591
592 return 0;
593}
594#endif
595
596int blk_trace_startstop(struct request_queue *q, int start)
597{
598 int ret;
599 struct blk_trace *bt = q->blk_trace;
600
601 if (bt == NULL)
602 return -EINVAL;
603
604 /*
605 * For starting a trace, we can transition from a setup or stopped
606 * trace. For stopping a trace, the state must be running
607 */
608 ret = -EINVAL;
609 if (start) {
610 if (bt->trace_state == Blktrace_setup ||
611 bt->trace_state == Blktrace_stopped) {
612 blktrace_seq++;
613 smp_mb();
614 bt->trace_state = Blktrace_running;
615 spin_lock_irq(&running_trace_lock);
616 list_add(&bt->running_list, &running_trace_list);
617 spin_unlock_irq(&running_trace_lock);
618
619 trace_note_time(bt);
620 ret = 0;
621 }
622 } else {
623 if (bt->trace_state == Blktrace_running) {
624 bt->trace_state = Blktrace_stopped;
625 spin_lock_irq(&running_trace_lock);
626 list_del_init(&bt->running_list);
627 spin_unlock_irq(&running_trace_lock);
628 relay_flush(bt->rchan);
629 ret = 0;
630 }
631 }
632
633 return ret;
634}
635EXPORT_SYMBOL_GPL(blk_trace_startstop);
636
637/**
638 * blk_trace_ioctl: - handle the ioctls associated with tracing
639 * @bdev: the block device
640 * @cmd: the ioctl cmd
641 * @arg: the argument data, if any
642 *
643 **/
644int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
645{
646 struct request_queue *q;
647 int ret, start = 0;
648 char b[BDEVNAME_SIZE];
649
650 q = bdev_get_queue(bdev);
651 if (!q)
652 return -ENXIO;
653
654 mutex_lock(&bdev->bd_mutex);
655
656 switch (cmd) {
657 case BLKTRACESETUP:
658 bdevname(bdev, b);
659 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
660 break;
661#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
662 case BLKTRACESETUP32:
663 bdevname(bdev, b);
664 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
665 break;
666#endif
667 case BLKTRACESTART:
668 start = 1;
669 case BLKTRACESTOP:
670 ret = blk_trace_startstop(q, start);
671 break;
672 case BLKTRACETEARDOWN:
673 ret = blk_trace_remove(q);
674 break;
675 default:
676 ret = -ENOTTY;
677 break;
678 }
679
680 mutex_unlock(&bdev->bd_mutex);
681 return ret;
682}
683
684/**
685 * blk_trace_shutdown: - stop and cleanup trace structures
686 * @q: the request queue associated with the device
687 *
688 **/
689void blk_trace_shutdown(struct request_queue *q)
690{
691 if (q->blk_trace) {
692 blk_trace_startstop(q, 0);
693 blk_trace_remove(q);
694 }
695}
696
697/*
698 * blktrace probes
699 */
700
701/**
702 * blk_add_trace_rq - Add a trace for a request oriented action
703 * @q: queue the io is for
704 * @rq: the source request
705 * @nr_bytes: number of completed bytes
706 * @what: the action
707 *
708 * Description:
709 * Records an action against a request. Will log the bio offset + size.
710 *
711 **/
712static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
713 unsigned int nr_bytes, u32 what)
714{
715 struct blk_trace *bt = q->blk_trace;
716
717 if (likely(!bt))
718 return;
719
720 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
721 what |= BLK_TC_ACT(BLK_TC_PC);
722 __blk_add_trace(bt, 0, nr_bytes, rq->cmd_flags,
723 what, rq->errors, rq->cmd_len, rq->cmd);
724 } else {
725 what |= BLK_TC_ACT(BLK_TC_FS);
726 __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes,
727 rq->cmd_flags, what, rq->errors, 0, NULL);
728 }
729}
730
731static void blk_add_trace_rq_abort(void *ignore,
732 struct request_queue *q, struct request *rq)
733{
734 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT);
735}
736
737static void blk_add_trace_rq_insert(void *ignore,
738 struct request_queue *q, struct request *rq)
739{
740 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT);
741}
742
743static void blk_add_trace_rq_issue(void *ignore,
744 struct request_queue *q, struct request *rq)
745{
746 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE);
747}
748
749static void blk_add_trace_rq_requeue(void *ignore,
750 struct request_queue *q,
751 struct request *rq)
752{
753 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE);
754}
755
756static void blk_add_trace_rq_complete(void *ignore,
757 struct request_queue *q,
758 struct request *rq,
759 unsigned int nr_bytes)
760{
761 blk_add_trace_rq(q, rq, nr_bytes, BLK_TA_COMPLETE);
762}
763
764/**
765 * blk_add_trace_bio - Add a trace for a bio oriented action
766 * @q: queue the io is for
767 * @bio: the source bio
768 * @what: the action
769 * @error: error, if any
770 *
771 * Description:
772 * Records an action against a bio. Will log the bio offset + size.
773 *
774 **/
775static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
776 u32 what, int error)
777{
778 struct blk_trace *bt = q->blk_trace;
779
780 if (likely(!bt))
781 return;
782
783 if (!error && !bio_flagged(bio, BIO_UPTODATE))
784 error = EIO;
785
786 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
787 bio->bi_rw, what, error, 0, NULL);
788}
789
790static void blk_add_trace_bio_bounce(void *ignore,
791 struct request_queue *q, struct bio *bio)
792{
793 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
794}
795
796static void blk_add_trace_bio_complete(void *ignore,
797 struct request_queue *q, struct bio *bio,
798 int error)
799{
800 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
801}
802
803static void blk_add_trace_bio_backmerge(void *ignore,
804 struct request_queue *q,
805 struct request *rq,
806 struct bio *bio)
807{
808 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
809}
810
811static void blk_add_trace_bio_frontmerge(void *ignore,
812 struct request_queue *q,
813 struct request *rq,
814 struct bio *bio)
815{
816 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
817}
818
819static void blk_add_trace_bio_queue(void *ignore,
820 struct request_queue *q, struct bio *bio)
821{
822 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
823}
824
825static void blk_add_trace_getrq(void *ignore,
826 struct request_queue *q,
827 struct bio *bio, int rw)
828{
829 if (bio)
830 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
831 else {
832 struct blk_trace *bt = q->blk_trace;
833
834 if (bt)
835 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
836 }
837}
838
839
840static void blk_add_trace_sleeprq(void *ignore,
841 struct request_queue *q,
842 struct bio *bio, int rw)
843{
844 if (bio)
845 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
846 else {
847 struct blk_trace *bt = q->blk_trace;
848
849 if (bt)
850 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
851 0, 0, NULL);
852 }
853}
854
855static void blk_add_trace_plug(void *ignore, struct request_queue *q)
856{
857 struct blk_trace *bt = q->blk_trace;
858
859 if (bt)
860 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
861}
862
863static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
864 unsigned int depth, bool explicit)
865{
866 struct blk_trace *bt = q->blk_trace;
867
868 if (bt) {
869 __be64 rpdu = cpu_to_be64(depth);
870 u32 what;
871
872 if (explicit)
873 what = BLK_TA_UNPLUG_IO;
874 else
875 what = BLK_TA_UNPLUG_TIMER;
876
877 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
878 }
879}
880
881static void blk_add_trace_split(void *ignore,
882 struct request_queue *q, struct bio *bio,
883 unsigned int pdu)
884{
885 struct blk_trace *bt = q->blk_trace;
886
887 if (bt) {
888 __be64 rpdu = cpu_to_be64(pdu);
889
890 __blk_add_trace(bt, bio->bi_iter.bi_sector,
891 bio->bi_iter.bi_size, bio->bi_rw, BLK_TA_SPLIT,
892 !bio_flagged(bio, BIO_UPTODATE),
893 sizeof(rpdu), &rpdu);
894 }
895}
896
897/**
898 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
899 * @ignore: trace callback data parameter (not used)
900 * @q: queue the io is for
901 * @bio: the source bio
902 * @dev: target device
903 * @from: source sector
904 *
905 * Description:
906 * Device mapper or raid target sometimes need to split a bio because
907 * it spans a stripe (or similar). Add a trace for that action.
908 *
909 **/
910static void blk_add_trace_bio_remap(void *ignore,
911 struct request_queue *q, struct bio *bio,
912 dev_t dev, sector_t from)
913{
914 struct blk_trace *bt = q->blk_trace;
915 struct blk_io_trace_remap r;
916
917 if (likely(!bt))
918 return;
919
920 r.device_from = cpu_to_be32(dev);
921 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
922 r.sector_from = cpu_to_be64(from);
923
924 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
925 bio->bi_rw, BLK_TA_REMAP,
926 !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
927}
928
929/**
930 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
931 * @ignore: trace callback data parameter (not used)
932 * @q: queue the io is for
933 * @rq: the source request
934 * @dev: target device
935 * @from: source sector
936 *
937 * Description:
938 * Device mapper remaps request to other devices.
939 * Add a trace for that action.
940 *
941 **/
942static void blk_add_trace_rq_remap(void *ignore,
943 struct request_queue *q,
944 struct request *rq, dev_t dev,
945 sector_t from)
946{
947 struct blk_trace *bt = q->blk_trace;
948 struct blk_io_trace_remap r;
949
950 if (likely(!bt))
951 return;
952
953 r.device_from = cpu_to_be32(dev);
954 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
955 r.sector_from = cpu_to_be64(from);
956
957 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
958 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
959 sizeof(r), &r);
960}
961
962/**
963 * blk_add_driver_data - Add binary message with driver-specific data
964 * @q: queue the io is for
965 * @rq: io request
966 * @data: driver-specific data
967 * @len: length of driver-specific data
968 *
969 * Description:
970 * Some drivers might want to write driver-specific data per request.
971 *
972 **/
973void blk_add_driver_data(struct request_queue *q,
974 struct request *rq,
975 void *data, size_t len)
976{
977 struct blk_trace *bt = q->blk_trace;
978
979 if (likely(!bt))
980 return;
981
982 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
983 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
984 BLK_TA_DRV_DATA, rq->errors, len, data);
985 else
986 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
987 BLK_TA_DRV_DATA, rq->errors, len, data);
988}
989EXPORT_SYMBOL_GPL(blk_add_driver_data);
990
991static void blk_register_tracepoints(void)
992{
993 int ret;
994
995 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1006 WARN_ON(ret);
1007 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1008 WARN_ON(ret);
1009 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1010 WARN_ON(ret);
1011 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1012 WARN_ON(ret);
1013 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1014 WARN_ON(ret);
1015 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1016 WARN_ON(ret);
1017 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1018 WARN_ON(ret);
1019 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1020 WARN_ON(ret);
1021 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1022 WARN_ON(ret);
1023 ret = register_trace_block_split(blk_add_trace_split, NULL);
1024 WARN_ON(ret);
1025 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1026 WARN_ON(ret);
1027 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1028 WARN_ON(ret);
1029}
1030
1031static void blk_unregister_tracepoints(void)
1032{
1033 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1034 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1035 unregister_trace_block_split(blk_add_trace_split, NULL);
1036 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1037 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1038 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1039 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1040 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1041 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1042 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1043 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1044 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1045 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1046 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1047 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1048 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1049 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1050
1051 tracepoint_synchronize_unregister();
1052}
1053
1054/*
1055 * struct blk_io_tracer formatting routines
1056 */
1057
1058static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1059{
1060 int i = 0;
1061 int tc = t->action >> BLK_TC_SHIFT;
1062
1063 if (t->action == BLK_TN_MESSAGE) {
1064 rwbs[i++] = 'N';
1065 goto out;
1066 }
1067
1068 if (tc & BLK_TC_FLUSH)
1069 rwbs[i++] = 'F';
1070
1071 if (tc & BLK_TC_DISCARD)
1072 rwbs[i++] = 'D';
1073 else if (tc & BLK_TC_WRITE)
1074 rwbs[i++] = 'W';
1075 else if (t->bytes)
1076 rwbs[i++] = 'R';
1077 else
1078 rwbs[i++] = 'N';
1079
1080 if (tc & BLK_TC_FUA)
1081 rwbs[i++] = 'F';
1082 if (tc & BLK_TC_AHEAD)
1083 rwbs[i++] = 'A';
1084 if (tc & BLK_TC_SYNC)
1085 rwbs[i++] = 'S';
1086 if (tc & BLK_TC_META)
1087 rwbs[i++] = 'M';
1088out:
1089 rwbs[i] = '\0';
1090}
1091
1092static inline
1093const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1094{
1095 return (const struct blk_io_trace *)ent;
1096}
1097
1098static inline const void *pdu_start(const struct trace_entry *ent)
1099{
1100 return te_blk_io_trace(ent) + 1;
1101}
1102
1103static inline u32 t_action(const struct trace_entry *ent)
1104{
1105 return te_blk_io_trace(ent)->action;
1106}
1107
1108static inline u32 t_bytes(const struct trace_entry *ent)
1109{
1110 return te_blk_io_trace(ent)->bytes;
1111}
1112
1113static inline u32 t_sec(const struct trace_entry *ent)
1114{
1115 return te_blk_io_trace(ent)->bytes >> 9;
1116}
1117
1118static inline unsigned long long t_sector(const struct trace_entry *ent)
1119{
1120 return te_blk_io_trace(ent)->sector;
1121}
1122
1123static inline __u16 t_error(const struct trace_entry *ent)
1124{
1125 return te_blk_io_trace(ent)->error;
1126}
1127
1128static __u64 get_pdu_int(const struct trace_entry *ent)
1129{
1130 const __u64 *val = pdu_start(ent);
1131 return be64_to_cpu(*val);
1132}
1133
1134static void get_pdu_remap(const struct trace_entry *ent,
1135 struct blk_io_trace_remap *r)
1136{
1137 const struct blk_io_trace_remap *__r = pdu_start(ent);
1138 __u64 sector_from = __r->sector_from;
1139
1140 r->device_from = be32_to_cpu(__r->device_from);
1141 r->device_to = be32_to_cpu(__r->device_to);
1142 r->sector_from = be64_to_cpu(sector_from);
1143}
1144
1145typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1146
1147static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1148{
1149 char rwbs[RWBS_LEN];
1150 unsigned long long ts = iter->ts;
1151 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1152 unsigned secs = (unsigned long)ts;
1153 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1154
1155 fill_rwbs(rwbs, t);
1156
1157 return trace_seq_printf(&iter->seq,
1158 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1159 MAJOR(t->device), MINOR(t->device), iter->cpu,
1160 secs, nsec_rem, iter->ent->pid, act, rwbs);
1161}
1162
1163static int blk_log_action(struct trace_iterator *iter, const char *act)
1164{
1165 char rwbs[RWBS_LEN];
1166 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1167
1168 fill_rwbs(rwbs, t);
1169 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1170 MAJOR(t->device), MINOR(t->device), act, rwbs);
1171}
1172
1173static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1174{
1175 const unsigned char *pdu_buf;
1176 int pdu_len;
1177 int i, end, ret;
1178
1179 pdu_buf = pdu_start(ent);
1180 pdu_len = te_blk_io_trace(ent)->pdu_len;
1181
1182 if (!pdu_len)
1183 return 1;
1184
1185 /* find the last zero that needs to be printed */
1186 for (end = pdu_len - 1; end >= 0; end--)
1187 if (pdu_buf[end])
1188 break;
1189 end++;
1190
1191 if (!trace_seq_putc(s, '('))
1192 return 0;
1193
1194 for (i = 0; i < pdu_len; i++) {
1195
1196 ret = trace_seq_printf(s, "%s%02x",
1197 i == 0 ? "" : " ", pdu_buf[i]);
1198 if (!ret)
1199 return ret;
1200
1201 /*
1202 * stop when the rest is just zeroes and indicate so
1203 * with a ".." appended
1204 */
1205 if (i == end && end != pdu_len - 1)
1206 return trace_seq_puts(s, " ..) ");
1207 }
1208
1209 return trace_seq_puts(s, ") ");
1210}
1211
1212static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1213{
1214 char cmd[TASK_COMM_LEN];
1215
1216 trace_find_cmdline(ent->pid, cmd);
1217
1218 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1219 int ret;
1220
1221 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1222 if (!ret)
1223 return 0;
1224 ret = blk_log_dump_pdu(s, ent);
1225 if (!ret)
1226 return 0;
1227 return trace_seq_printf(s, "[%s]\n", cmd);
1228 } else {
1229 if (t_sec(ent))
1230 return trace_seq_printf(s, "%llu + %u [%s]\n",
1231 t_sector(ent), t_sec(ent), cmd);
1232 return trace_seq_printf(s, "[%s]\n", cmd);
1233 }
1234}
1235
1236static int blk_log_with_error(struct trace_seq *s,
1237 const struct trace_entry *ent)
1238{
1239 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1240 int ret;
1241
1242 ret = blk_log_dump_pdu(s, ent);
1243 if (ret)
1244 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1245 return 0;
1246 } else {
1247 if (t_sec(ent))
1248 return trace_seq_printf(s, "%llu + %u [%d]\n",
1249 t_sector(ent),
1250 t_sec(ent), t_error(ent));
1251 return trace_seq_printf(s, "%llu [%d]\n",
1252 t_sector(ent), t_error(ent));
1253 }
1254}
1255
1256static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1257{
1258 struct blk_io_trace_remap r = { .device_from = 0, };
1259
1260 get_pdu_remap(ent, &r);
1261 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1262 t_sector(ent), t_sec(ent),
1263 MAJOR(r.device_from), MINOR(r.device_from),
1264 (unsigned long long)r.sector_from);
1265}
1266
1267static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1268{
1269 char cmd[TASK_COMM_LEN];
1270
1271 trace_find_cmdline(ent->pid, cmd);
1272
1273 return trace_seq_printf(s, "[%s]\n", cmd);
1274}
1275
1276static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1277{
1278 char cmd[TASK_COMM_LEN];
1279
1280 trace_find_cmdline(ent->pid, cmd);
1281
1282 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1283}
1284
1285static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1286{
1287 char cmd[TASK_COMM_LEN];
1288
1289 trace_find_cmdline(ent->pid, cmd);
1290
1291 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1292 get_pdu_int(ent), cmd);
1293}
1294
1295static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1296{
1297 int ret;
1298 const struct blk_io_trace *t = te_blk_io_trace(ent);
1299
1300 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1301 if (ret)
1302 return trace_seq_putc(s, '\n');
1303 return ret;
1304}
1305
1306/*
1307 * struct tracer operations
1308 */
1309
1310static void blk_tracer_print_header(struct seq_file *m)
1311{
1312 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1313 return;
1314 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1315 "# | | | | | |\n");
1316}
1317
1318static void blk_tracer_start(struct trace_array *tr)
1319{
1320 blk_tracer_enabled = true;
1321}
1322
1323static int blk_tracer_init(struct trace_array *tr)
1324{
1325 blk_tr = tr;
1326 blk_tracer_start(tr);
1327 return 0;
1328}
1329
1330static void blk_tracer_stop(struct trace_array *tr)
1331{
1332 blk_tracer_enabled = false;
1333}
1334
1335static void blk_tracer_reset(struct trace_array *tr)
1336{
1337 blk_tracer_stop(tr);
1338}
1339
1340static const struct {
1341 const char *act[2];
1342 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1343} what2act[] = {
1344 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1345 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1346 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1347 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1348 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1349 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1350 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1351 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1352 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1353 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1354 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1355 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1356 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1357 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1358 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1359};
1360
1361static enum print_line_t print_one_line(struct trace_iterator *iter,
1362 bool classic)
1363{
1364 struct trace_seq *s = &iter->seq;
1365 const struct blk_io_trace *t;
1366 u16 what;
1367 int ret;
1368 bool long_act;
1369 blk_log_action_t *log_action;
1370
1371 t = te_blk_io_trace(iter->ent);
1372 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1373 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1374 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1375
1376 if (t->action == BLK_TN_MESSAGE) {
1377 ret = log_action(iter, long_act ? "message" : "m");
1378 if (ret)
1379 ret = blk_log_msg(s, iter->ent);
1380 goto out;
1381 }
1382
1383 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1384 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1385 else {
1386 ret = log_action(iter, what2act[what].act[long_act]);
1387 if (ret)
1388 ret = what2act[what].print(s, iter->ent);
1389 }
1390out:
1391 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1392}
1393
1394static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1395 int flags, struct trace_event *event)
1396{
1397 return print_one_line(iter, false);
1398}
1399
1400static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1401{
1402 struct trace_seq *s = &iter->seq;
1403 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1404 const int offset = offsetof(struct blk_io_trace, sector);
1405 struct blk_io_trace old = {
1406 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1407 .time = iter->ts,
1408 };
1409
1410 if (!trace_seq_putmem(s, &old, offset))
1411 return 0;
1412 return trace_seq_putmem(s, &t->sector,
1413 sizeof(old) - offset + t->pdu_len);
1414}
1415
1416static enum print_line_t
1417blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1418 struct trace_event *event)
1419{
1420 return blk_trace_synthesize_old_trace(iter) ?
1421 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1422}
1423
1424static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1425{
1426 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1427 return TRACE_TYPE_UNHANDLED;
1428
1429 return print_one_line(iter, true);
1430}
1431
1432static int
1433blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1434{
1435 /* don't output context-info for blk_classic output */
1436 if (bit == TRACE_BLK_OPT_CLASSIC) {
1437 if (set)
1438 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1439 else
1440 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1441 }
1442 return 0;
1443}
1444
1445static struct tracer blk_tracer __read_mostly = {
1446 .name = "blk",
1447 .init = blk_tracer_init,
1448 .reset = blk_tracer_reset,
1449 .start = blk_tracer_start,
1450 .stop = blk_tracer_stop,
1451 .print_header = blk_tracer_print_header,
1452 .print_line = blk_tracer_print_line,
1453 .flags = &blk_tracer_flags,
1454 .set_flag = blk_tracer_set_flag,
1455};
1456
1457static struct trace_event_functions trace_blk_event_funcs = {
1458 .trace = blk_trace_event_print,
1459 .binary = blk_trace_event_print_binary,
1460};
1461
1462static struct trace_event trace_blk_event = {
1463 .type = TRACE_BLK,
1464 .funcs = &trace_blk_event_funcs,
1465};
1466
1467static int __init init_blk_tracer(void)
1468{
1469 if (!register_ftrace_event(&trace_blk_event)) {
1470 pr_warning("Warning: could not register block events\n");
1471 return 1;
1472 }
1473
1474 if (register_tracer(&blk_tracer) != 0) {
1475 pr_warning("Warning: could not register the block tracer\n");
1476 unregister_ftrace_event(&trace_blk_event);
1477 return 1;
1478 }
1479
1480 return 0;
1481}
1482
1483device_initcall(init_blk_tracer);
1484
1485static int blk_trace_remove_queue(struct request_queue *q)
1486{
1487 struct blk_trace *bt;
1488
1489 bt = xchg(&q->blk_trace, NULL);
1490 if (bt == NULL)
1491 return -EINVAL;
1492
1493 if (atomic_dec_and_test(&blk_probes_ref))
1494 blk_unregister_tracepoints();
1495
1496 spin_lock_irq(&running_trace_lock);
1497 list_del(&bt->running_list);
1498 spin_unlock_irq(&running_trace_lock);
1499 blk_trace_free(bt);
1500 return 0;
1501}
1502
1503/*
1504 * Setup everything required to start tracing
1505 */
1506static int blk_trace_setup_queue(struct request_queue *q,
1507 struct block_device *bdev)
1508{
1509 struct blk_trace *old_bt, *bt = NULL;
1510 int ret = -ENOMEM;
1511
1512 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1513 if (!bt)
1514 return -ENOMEM;
1515
1516 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1517 if (!bt->msg_data)
1518 goto free_bt;
1519
1520 bt->dev = bdev->bd_dev;
1521 bt->act_mask = (u16)-1;
1522
1523 blk_trace_setup_lba(bt, bdev);
1524
1525 old_bt = xchg(&q->blk_trace, bt);
1526 if (old_bt != NULL) {
1527 (void)xchg(&q->blk_trace, old_bt);
1528 ret = -EBUSY;
1529 goto free_bt;
1530 }
1531
1532 if (atomic_inc_return(&blk_probes_ref) == 1)
1533 blk_register_tracepoints();
1534 return 0;
1535
1536free_bt:
1537 blk_trace_free(bt);
1538 return ret;
1539}
1540
1541/*
1542 * sysfs interface to enable and configure tracing
1543 */
1544
1545static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1546 struct device_attribute *attr,
1547 char *buf);
1548static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1549 struct device_attribute *attr,
1550 const char *buf, size_t count);
1551#define BLK_TRACE_DEVICE_ATTR(_name) \
1552 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1553 sysfs_blk_trace_attr_show, \
1554 sysfs_blk_trace_attr_store)
1555
1556static BLK_TRACE_DEVICE_ATTR(enable);
1557static BLK_TRACE_DEVICE_ATTR(act_mask);
1558static BLK_TRACE_DEVICE_ATTR(pid);
1559static BLK_TRACE_DEVICE_ATTR(start_lba);
1560static BLK_TRACE_DEVICE_ATTR(end_lba);
1561
1562static struct attribute *blk_trace_attrs[] = {
1563 &dev_attr_enable.attr,
1564 &dev_attr_act_mask.attr,
1565 &dev_attr_pid.attr,
1566 &dev_attr_start_lba.attr,
1567 &dev_attr_end_lba.attr,
1568 NULL
1569};
1570
1571struct attribute_group blk_trace_attr_group = {
1572 .name = "trace",
1573 .attrs = blk_trace_attrs,
1574};
1575
1576static const struct {
1577 int mask;
1578 const char *str;
1579} mask_maps[] = {
1580 { BLK_TC_READ, "read" },
1581 { BLK_TC_WRITE, "write" },
1582 { BLK_TC_FLUSH, "flush" },
1583 { BLK_TC_SYNC, "sync" },
1584 { BLK_TC_QUEUE, "queue" },
1585 { BLK_TC_REQUEUE, "requeue" },
1586 { BLK_TC_ISSUE, "issue" },
1587 { BLK_TC_COMPLETE, "complete" },
1588 { BLK_TC_FS, "fs" },
1589 { BLK_TC_PC, "pc" },
1590 { BLK_TC_AHEAD, "ahead" },
1591 { BLK_TC_META, "meta" },
1592 { BLK_TC_DISCARD, "discard" },
1593 { BLK_TC_DRV_DATA, "drv_data" },
1594 { BLK_TC_FUA, "fua" },
1595};
1596
1597static int blk_trace_str2mask(const char *str)
1598{
1599 int i;
1600 int mask = 0;
1601 char *buf, *s, *token;
1602
1603 buf = kstrdup(str, GFP_KERNEL);
1604 if (buf == NULL)
1605 return -ENOMEM;
1606 s = strstrip(buf);
1607
1608 while (1) {
1609 token = strsep(&s, ",");
1610 if (token == NULL)
1611 break;
1612
1613 if (*token == '\0')
1614 continue;
1615
1616 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1617 if (strcasecmp(token, mask_maps[i].str) == 0) {
1618 mask |= mask_maps[i].mask;
1619 break;
1620 }
1621 }
1622 if (i == ARRAY_SIZE(mask_maps)) {
1623 mask = -EINVAL;
1624 break;
1625 }
1626 }
1627 kfree(buf);
1628
1629 return mask;
1630}
1631
1632static ssize_t blk_trace_mask2str(char *buf, int mask)
1633{
1634 int i;
1635 char *p = buf;
1636
1637 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1638 if (mask & mask_maps[i].mask) {
1639 p += sprintf(p, "%s%s",
1640 (p == buf) ? "" : ",", mask_maps[i].str);
1641 }
1642 }
1643 *p++ = '\n';
1644
1645 return p - buf;
1646}
1647
1648static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1649{
1650 if (bdev->bd_disk == NULL)
1651 return NULL;
1652
1653 return bdev_get_queue(bdev);
1654}
1655
1656static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1657 struct device_attribute *attr,
1658 char *buf)
1659{
1660 struct hd_struct *p = dev_to_part(dev);
1661 struct request_queue *q;
1662 struct block_device *bdev;
1663 ssize_t ret = -ENXIO;
1664
1665 bdev = bdget(part_devt(p));
1666 if (bdev == NULL)
1667 goto out;
1668
1669 q = blk_trace_get_queue(bdev);
1670 if (q == NULL)
1671 goto out_bdput;
1672
1673 mutex_lock(&bdev->bd_mutex);
1674
1675 if (attr == &dev_attr_enable) {
1676 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1677 goto out_unlock_bdev;
1678 }
1679
1680 if (q->blk_trace == NULL)
1681 ret = sprintf(buf, "disabled\n");
1682 else if (attr == &dev_attr_act_mask)
1683 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1684 else if (attr == &dev_attr_pid)
1685 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1686 else if (attr == &dev_attr_start_lba)
1687 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1688 else if (attr == &dev_attr_end_lba)
1689 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1690
1691out_unlock_bdev:
1692 mutex_unlock(&bdev->bd_mutex);
1693out_bdput:
1694 bdput(bdev);
1695out:
1696 return ret;
1697}
1698
1699static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1700 struct device_attribute *attr,
1701 const char *buf, size_t count)
1702{
1703 struct block_device *bdev;
1704 struct request_queue *q;
1705 struct hd_struct *p;
1706 u64 value;
1707 ssize_t ret = -EINVAL;
1708
1709 if (count == 0)
1710 goto out;
1711
1712 if (attr == &dev_attr_act_mask) {
1713 if (sscanf(buf, "%llx", &value) != 1) {
1714 /* Assume it is a list of trace category names */
1715 ret = blk_trace_str2mask(buf);
1716 if (ret < 0)
1717 goto out;
1718 value = ret;
1719 }
1720 } else if (sscanf(buf, "%llu", &value) != 1)
1721 goto out;
1722
1723 ret = -ENXIO;
1724
1725 p = dev_to_part(dev);
1726 bdev = bdget(part_devt(p));
1727 if (bdev == NULL)
1728 goto out;
1729
1730 q = blk_trace_get_queue(bdev);
1731 if (q == NULL)
1732 goto out_bdput;
1733
1734 mutex_lock(&bdev->bd_mutex);
1735
1736 if (attr == &dev_attr_enable) {
1737 if (value)
1738 ret = blk_trace_setup_queue(q, bdev);
1739 else
1740 ret = blk_trace_remove_queue(q);
1741 goto out_unlock_bdev;
1742 }
1743
1744 ret = 0;
1745 if (q->blk_trace == NULL)
1746 ret = blk_trace_setup_queue(q, bdev);
1747
1748 if (ret == 0) {
1749 if (attr == &dev_attr_act_mask)
1750 q->blk_trace->act_mask = value;
1751 else if (attr == &dev_attr_pid)
1752 q->blk_trace->pid = value;
1753 else if (attr == &dev_attr_start_lba)
1754 q->blk_trace->start_lba = value;
1755 else if (attr == &dev_attr_end_lba)
1756 q->blk_trace->end_lba = value;
1757 }
1758
1759out_unlock_bdev:
1760 mutex_unlock(&bdev->bd_mutex);
1761out_bdput:
1762 bdput(bdev);
1763out:
1764 return ret ? ret : count;
1765}
1766
1767int blk_trace_init_sysfs(struct device *dev)
1768{
1769 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1770}
1771
1772void blk_trace_remove_sysfs(struct device *dev)
1773{
1774 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1775}
1776
1777#endif /* CONFIG_BLK_DEV_IO_TRACE */
1778
1779#ifdef CONFIG_EVENT_TRACING
1780
1781void blk_dump_cmd(char *buf, struct request *rq)
1782{
1783 int i, end;
1784 int len = rq->cmd_len;
1785 unsigned char *cmd = rq->cmd;
1786
1787 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1788 buf[0] = '\0';
1789 return;
1790 }
1791
1792 for (end = len - 1; end >= 0; end--)
1793 if (cmd[end])
1794 break;
1795 end++;
1796
1797 for (i = 0; i < len; i++) {
1798 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1799 if (i == end && end != len - 1) {
1800 sprintf(buf, " ..");
1801 break;
1802 }
1803 }
1804}
1805
1806void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1807{
1808 int i = 0;
1809
1810 if (rw & REQ_FLUSH)
1811 rwbs[i++] = 'F';
1812
1813 if (rw & WRITE)
1814 rwbs[i++] = 'W';
1815 else if (rw & REQ_DISCARD)
1816 rwbs[i++] = 'D';
1817 else if (bytes)
1818 rwbs[i++] = 'R';
1819 else
1820 rwbs[i++] = 'N';
1821
1822 if (rw & REQ_FUA)
1823 rwbs[i++] = 'F';
1824 if (rw & REQ_RAHEAD)
1825 rwbs[i++] = 'A';
1826 if (rw & REQ_SYNC)
1827 rwbs[i++] = 'S';
1828 if (rw & REQ_META)
1829 rwbs[i++] = 'M';
1830 if (rw & REQ_SECURE)
1831 rwbs[i++] = 'E';
1832
1833 rwbs[i] = '\0';
1834}
1835EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1836
1837#endif /* CONFIG_EVENT_TRACING */
1838
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/time.h>
27#include <linux/uaccess.h>
28
29#include <trace/events/block.h>
30
31#include "trace_output.h"
32
33#ifdef CONFIG_BLK_DEV_IO_TRACE
34
35static unsigned int blktrace_seq __read_mostly = 1;
36
37static struct trace_array *blk_tr;
38static bool blk_tracer_enabled __read_mostly;
39
40/* Select an alternative, minimalistic output than the original one */
41#define TRACE_BLK_OPT_CLASSIC 0x1
42
43static struct tracer_opt blk_tracer_opts[] = {
44 /* Default disable the minimalistic output */
45 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
46 { }
47};
48
49static struct tracer_flags blk_tracer_flags = {
50 .val = 0,
51 .opts = blk_tracer_opts,
52};
53
54/* Global reference count of probes */
55static atomic_t blk_probes_ref = ATOMIC_INIT(0);
56
57static void blk_register_tracepoints(void);
58static void blk_unregister_tracepoints(void);
59
60/*
61 * Send out a notify message.
62 */
63static void trace_note(struct blk_trace *bt, pid_t pid, int action,
64 const void *data, size_t len)
65{
66 struct blk_io_trace *t;
67 struct ring_buffer_event *event = NULL;
68 struct ring_buffer *buffer = NULL;
69 int pc = 0;
70 int cpu = smp_processor_id();
71 bool blk_tracer = blk_tracer_enabled;
72
73 if (blk_tracer) {
74 buffer = blk_tr->buffer;
75 pc = preempt_count();
76 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
77 sizeof(*t) + len,
78 0, pc);
79 if (!event)
80 return;
81 t = ring_buffer_event_data(event);
82 goto record_it;
83 }
84
85 if (!bt->rchan)
86 return;
87
88 t = relay_reserve(bt->rchan, sizeof(*t) + len);
89 if (t) {
90 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
91 t->time = ktime_to_ns(ktime_get());
92record_it:
93 t->device = bt->dev;
94 t->action = action;
95 t->pid = pid;
96 t->cpu = cpu;
97 t->pdu_len = len;
98 memcpy((void *) t + sizeof(*t), data, len);
99
100 if (blk_tracer)
101 trace_buffer_unlock_commit(buffer, event, 0, pc);
102 }
103}
104
105/*
106 * Send out a notify for this process, if we haven't done so since a trace
107 * started
108 */
109static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
110{
111 tsk->btrace_seq = blktrace_seq;
112 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
113}
114
115static void trace_note_time(struct blk_trace *bt)
116{
117 struct timespec now;
118 unsigned long flags;
119 u32 words[2];
120
121 getnstimeofday(&now);
122 words[0] = now.tv_sec;
123 words[1] = now.tv_nsec;
124
125 local_irq_save(flags);
126 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
127 local_irq_restore(flags);
128}
129
130void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
131{
132 int n;
133 va_list args;
134 unsigned long flags;
135 char *buf;
136
137 if (unlikely(bt->trace_state != Blktrace_running &&
138 !blk_tracer_enabled))
139 return;
140
141 /*
142 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
143 * message to the trace.
144 */
145 if (!(bt->act_mask & BLK_TC_NOTIFY))
146 return;
147
148 local_irq_save(flags);
149 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
150 va_start(args, fmt);
151 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
152 va_end(args);
153
154 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
155 local_irq_restore(flags);
156}
157EXPORT_SYMBOL_GPL(__trace_note_message);
158
159static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
160 pid_t pid)
161{
162 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
163 return 1;
164 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
165 return 1;
166 if (bt->pid && pid != bt->pid)
167 return 1;
168
169 return 0;
170}
171
172/*
173 * Data direction bit lookup
174 */
175static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
176 BLK_TC_ACT(BLK_TC_WRITE) };
177
178#define BLK_TC_RAHEAD BLK_TC_AHEAD
179
180/* The ilog2() calls fall out because they're constant */
181#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
182 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
183
184/*
185 * The worker for the various blk_add_trace*() types. Fills out a
186 * blk_io_trace structure and places it in a per-cpu subbuffer.
187 */
188static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
189 int rw, u32 what, int error, int pdu_len, void *pdu_data)
190{
191 struct task_struct *tsk = current;
192 struct ring_buffer_event *event = NULL;
193 struct ring_buffer *buffer = NULL;
194 struct blk_io_trace *t;
195 unsigned long flags = 0;
196 unsigned long *sequence;
197 pid_t pid;
198 int cpu, pc = 0;
199 bool blk_tracer = blk_tracer_enabled;
200
201 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
202 return;
203
204 what |= ddir_act[rw & WRITE];
205 what |= MASK_TC_BIT(rw, SYNC);
206 what |= MASK_TC_BIT(rw, RAHEAD);
207 what |= MASK_TC_BIT(rw, META);
208 what |= MASK_TC_BIT(rw, DISCARD);
209 what |= MASK_TC_BIT(rw, FLUSH);
210 what |= MASK_TC_BIT(rw, FUA);
211
212 pid = tsk->pid;
213 if (act_log_check(bt, what, sector, pid))
214 return;
215 cpu = raw_smp_processor_id();
216
217 if (blk_tracer) {
218 tracing_record_cmdline(current);
219
220 buffer = blk_tr->buffer;
221 pc = preempt_count();
222 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
223 sizeof(*t) + pdu_len,
224 0, pc);
225 if (!event)
226 return;
227 t = ring_buffer_event_data(event);
228 goto record_it;
229 }
230
231 /*
232 * A word about the locking here - we disable interrupts to reserve
233 * some space in the relay per-cpu buffer, to prevent an irq
234 * from coming in and stepping on our toes.
235 */
236 local_irq_save(flags);
237
238 if (unlikely(tsk->btrace_seq != blktrace_seq))
239 trace_note_tsk(bt, tsk);
240
241 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
242 if (t) {
243 sequence = per_cpu_ptr(bt->sequence, cpu);
244
245 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
246 t->sequence = ++(*sequence);
247 t->time = ktime_to_ns(ktime_get());
248record_it:
249 /*
250 * These two are not needed in ftrace as they are in the
251 * generic trace_entry, filled by tracing_generic_entry_update,
252 * but for the trace_event->bin() synthesizer benefit we do it
253 * here too.
254 */
255 t->cpu = cpu;
256 t->pid = pid;
257
258 t->sector = sector;
259 t->bytes = bytes;
260 t->action = what;
261 t->device = bt->dev;
262 t->error = error;
263 t->pdu_len = pdu_len;
264
265 if (pdu_len)
266 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
267
268 if (blk_tracer) {
269 trace_buffer_unlock_commit(buffer, event, 0, pc);
270 return;
271 }
272 }
273
274 local_irq_restore(flags);
275}
276
277static struct dentry *blk_tree_root;
278static DEFINE_MUTEX(blk_tree_mutex);
279
280static void blk_trace_free(struct blk_trace *bt)
281{
282 debugfs_remove(bt->msg_file);
283 debugfs_remove(bt->dropped_file);
284 relay_close(bt->rchan);
285 debugfs_remove(bt->dir);
286 free_percpu(bt->sequence);
287 free_percpu(bt->msg_data);
288 kfree(bt);
289}
290
291static void blk_trace_cleanup(struct blk_trace *bt)
292{
293 blk_trace_free(bt);
294 if (atomic_dec_and_test(&blk_probes_ref))
295 blk_unregister_tracepoints();
296}
297
298int blk_trace_remove(struct request_queue *q)
299{
300 struct blk_trace *bt;
301
302 bt = xchg(&q->blk_trace, NULL);
303 if (!bt)
304 return -EINVAL;
305
306 if (bt->trace_state != Blktrace_running)
307 blk_trace_cleanup(bt);
308
309 return 0;
310}
311EXPORT_SYMBOL_GPL(blk_trace_remove);
312
313static int blk_dropped_open(struct inode *inode, struct file *filp)
314{
315 filp->private_data = inode->i_private;
316
317 return 0;
318}
319
320static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
321 size_t count, loff_t *ppos)
322{
323 struct blk_trace *bt = filp->private_data;
324 char buf[16];
325
326 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
327
328 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
329}
330
331static const struct file_operations blk_dropped_fops = {
332 .owner = THIS_MODULE,
333 .open = blk_dropped_open,
334 .read = blk_dropped_read,
335 .llseek = default_llseek,
336};
337
338static int blk_msg_open(struct inode *inode, struct file *filp)
339{
340 filp->private_data = inode->i_private;
341
342 return 0;
343}
344
345static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
346 size_t count, loff_t *ppos)
347{
348 char *msg;
349 struct blk_trace *bt;
350
351 if (count >= BLK_TN_MAX_MSG)
352 return -EINVAL;
353
354 msg = kmalloc(count + 1, GFP_KERNEL);
355 if (msg == NULL)
356 return -ENOMEM;
357
358 if (copy_from_user(msg, buffer, count)) {
359 kfree(msg);
360 return -EFAULT;
361 }
362
363 msg[count] = '\0';
364 bt = filp->private_data;
365 __trace_note_message(bt, "%s", msg);
366 kfree(msg);
367
368 return count;
369}
370
371static const struct file_operations blk_msg_fops = {
372 .owner = THIS_MODULE,
373 .open = blk_msg_open,
374 .write = blk_msg_write,
375 .llseek = noop_llseek,
376};
377
378/*
379 * Keep track of how many times we encountered a full subbuffer, to aid
380 * the user space app in telling how many lost events there were.
381 */
382static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
383 void *prev_subbuf, size_t prev_padding)
384{
385 struct blk_trace *bt;
386
387 if (!relay_buf_full(buf))
388 return 1;
389
390 bt = buf->chan->private_data;
391 atomic_inc(&bt->dropped);
392 return 0;
393}
394
395static int blk_remove_buf_file_callback(struct dentry *dentry)
396{
397 debugfs_remove(dentry);
398
399 return 0;
400}
401
402static struct dentry *blk_create_buf_file_callback(const char *filename,
403 struct dentry *parent,
404 int mode,
405 struct rchan_buf *buf,
406 int *is_global)
407{
408 return debugfs_create_file(filename, mode, parent, buf,
409 &relay_file_operations);
410}
411
412static struct rchan_callbacks blk_relay_callbacks = {
413 .subbuf_start = blk_subbuf_start_callback,
414 .create_buf_file = blk_create_buf_file_callback,
415 .remove_buf_file = blk_remove_buf_file_callback,
416};
417
418static void blk_trace_setup_lba(struct blk_trace *bt,
419 struct block_device *bdev)
420{
421 struct hd_struct *part = NULL;
422
423 if (bdev)
424 part = bdev->bd_part;
425
426 if (part) {
427 bt->start_lba = part->start_sect;
428 bt->end_lba = part->start_sect + part->nr_sects;
429 } else {
430 bt->start_lba = 0;
431 bt->end_lba = -1ULL;
432 }
433}
434
435/*
436 * Setup everything required to start tracing
437 */
438int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
439 struct block_device *bdev,
440 struct blk_user_trace_setup *buts)
441{
442 struct blk_trace *old_bt, *bt = NULL;
443 struct dentry *dir = NULL;
444 int ret, i;
445
446 if (!buts->buf_size || !buts->buf_nr)
447 return -EINVAL;
448
449 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
450 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
451
452 /*
453 * some device names have larger paths - convert the slashes
454 * to underscores for this to work as expected
455 */
456 for (i = 0; i < strlen(buts->name); i++)
457 if (buts->name[i] == '/')
458 buts->name[i] = '_';
459
460 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
461 if (!bt)
462 return -ENOMEM;
463
464 ret = -ENOMEM;
465 bt->sequence = alloc_percpu(unsigned long);
466 if (!bt->sequence)
467 goto err;
468
469 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
470 if (!bt->msg_data)
471 goto err;
472
473 ret = -ENOENT;
474
475 mutex_lock(&blk_tree_mutex);
476 if (!blk_tree_root) {
477 blk_tree_root = debugfs_create_dir("block", NULL);
478 if (!blk_tree_root) {
479 mutex_unlock(&blk_tree_mutex);
480 goto err;
481 }
482 }
483 mutex_unlock(&blk_tree_mutex);
484
485 dir = debugfs_create_dir(buts->name, blk_tree_root);
486
487 if (!dir)
488 goto err;
489
490 bt->dir = dir;
491 bt->dev = dev;
492 atomic_set(&bt->dropped, 0);
493
494 ret = -EIO;
495 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
496 &blk_dropped_fops);
497 if (!bt->dropped_file)
498 goto err;
499
500 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
501 if (!bt->msg_file)
502 goto err;
503
504 bt->rchan = relay_open("trace", dir, buts->buf_size,
505 buts->buf_nr, &blk_relay_callbacks, bt);
506 if (!bt->rchan)
507 goto err;
508
509 bt->act_mask = buts->act_mask;
510 if (!bt->act_mask)
511 bt->act_mask = (u16) -1;
512
513 blk_trace_setup_lba(bt, bdev);
514
515 /* overwrite with user settings */
516 if (buts->start_lba)
517 bt->start_lba = buts->start_lba;
518 if (buts->end_lba)
519 bt->end_lba = buts->end_lba;
520
521 bt->pid = buts->pid;
522 bt->trace_state = Blktrace_setup;
523
524 ret = -EBUSY;
525 old_bt = xchg(&q->blk_trace, bt);
526 if (old_bt) {
527 (void) xchg(&q->blk_trace, old_bt);
528 goto err;
529 }
530
531 if (atomic_inc_return(&blk_probes_ref) == 1)
532 blk_register_tracepoints();
533
534 return 0;
535err:
536 blk_trace_free(bt);
537 return ret;
538}
539
540int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
541 struct block_device *bdev,
542 char __user *arg)
543{
544 struct blk_user_trace_setup buts;
545 int ret;
546
547 ret = copy_from_user(&buts, arg, sizeof(buts));
548 if (ret)
549 return -EFAULT;
550
551 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
552 if (ret)
553 return ret;
554
555 if (copy_to_user(arg, &buts, sizeof(buts))) {
556 blk_trace_remove(q);
557 return -EFAULT;
558 }
559 return 0;
560}
561EXPORT_SYMBOL_GPL(blk_trace_setup);
562
563#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
564static int compat_blk_trace_setup(struct request_queue *q, char *name,
565 dev_t dev, struct block_device *bdev,
566 char __user *arg)
567{
568 struct blk_user_trace_setup buts;
569 struct compat_blk_user_trace_setup cbuts;
570 int ret;
571
572 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
573 return -EFAULT;
574
575 buts = (struct blk_user_trace_setup) {
576 .act_mask = cbuts.act_mask,
577 .buf_size = cbuts.buf_size,
578 .buf_nr = cbuts.buf_nr,
579 .start_lba = cbuts.start_lba,
580 .end_lba = cbuts.end_lba,
581 .pid = cbuts.pid,
582 };
583 memcpy(&buts.name, &cbuts.name, 32);
584
585 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
586 if (ret)
587 return ret;
588
589 if (copy_to_user(arg, &buts.name, 32)) {
590 blk_trace_remove(q);
591 return -EFAULT;
592 }
593
594 return 0;
595}
596#endif
597
598int blk_trace_startstop(struct request_queue *q, int start)
599{
600 int ret;
601 struct blk_trace *bt = q->blk_trace;
602
603 if (bt == NULL)
604 return -EINVAL;
605
606 /*
607 * For starting a trace, we can transition from a setup or stopped
608 * trace. For stopping a trace, the state must be running
609 */
610 ret = -EINVAL;
611 if (start) {
612 if (bt->trace_state == Blktrace_setup ||
613 bt->trace_state == Blktrace_stopped) {
614 blktrace_seq++;
615 smp_mb();
616 bt->trace_state = Blktrace_running;
617
618 trace_note_time(bt);
619 ret = 0;
620 }
621 } else {
622 if (bt->trace_state == Blktrace_running) {
623 bt->trace_state = Blktrace_stopped;
624 relay_flush(bt->rchan);
625 ret = 0;
626 }
627 }
628
629 return ret;
630}
631EXPORT_SYMBOL_GPL(blk_trace_startstop);
632
633/**
634 * blk_trace_ioctl: - handle the ioctls associated with tracing
635 * @bdev: the block device
636 * @cmd: the ioctl cmd
637 * @arg: the argument data, if any
638 *
639 **/
640int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
641{
642 struct request_queue *q;
643 int ret, start = 0;
644 char b[BDEVNAME_SIZE];
645
646 q = bdev_get_queue(bdev);
647 if (!q)
648 return -ENXIO;
649
650 mutex_lock(&bdev->bd_mutex);
651
652 switch (cmd) {
653 case BLKTRACESETUP:
654 bdevname(bdev, b);
655 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
656 break;
657#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
658 case BLKTRACESETUP32:
659 bdevname(bdev, b);
660 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
661 break;
662#endif
663 case BLKTRACESTART:
664 start = 1;
665 case BLKTRACESTOP:
666 ret = blk_trace_startstop(q, start);
667 break;
668 case BLKTRACETEARDOWN:
669 ret = blk_trace_remove(q);
670 break;
671 default:
672 ret = -ENOTTY;
673 break;
674 }
675
676 mutex_unlock(&bdev->bd_mutex);
677 return ret;
678}
679
680/**
681 * blk_trace_shutdown: - stop and cleanup trace structures
682 * @q: the request queue associated with the device
683 *
684 **/
685void blk_trace_shutdown(struct request_queue *q)
686{
687 if (q->blk_trace) {
688 blk_trace_startstop(q, 0);
689 blk_trace_remove(q);
690 }
691}
692
693/*
694 * blktrace probes
695 */
696
697/**
698 * blk_add_trace_rq - Add a trace for a request oriented action
699 * @q: queue the io is for
700 * @rq: the source request
701 * @what: the action
702 *
703 * Description:
704 * Records an action against a request. Will log the bio offset + size.
705 *
706 **/
707static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
708 u32 what)
709{
710 struct blk_trace *bt = q->blk_trace;
711
712 if (likely(!bt))
713 return;
714
715 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
716 what |= BLK_TC_ACT(BLK_TC_PC);
717 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
718 what, rq->errors, rq->cmd_len, rq->cmd);
719 } else {
720 what |= BLK_TC_ACT(BLK_TC_FS);
721 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
722 rq->cmd_flags, what, rq->errors, 0, NULL);
723 }
724}
725
726static void blk_add_trace_rq_abort(void *ignore,
727 struct request_queue *q, struct request *rq)
728{
729 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
730}
731
732static void blk_add_trace_rq_insert(void *ignore,
733 struct request_queue *q, struct request *rq)
734{
735 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
736}
737
738static void blk_add_trace_rq_issue(void *ignore,
739 struct request_queue *q, struct request *rq)
740{
741 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
742}
743
744static void blk_add_trace_rq_requeue(void *ignore,
745 struct request_queue *q,
746 struct request *rq)
747{
748 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
749}
750
751static void blk_add_trace_rq_complete(void *ignore,
752 struct request_queue *q,
753 struct request *rq)
754{
755 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
756}
757
758/**
759 * blk_add_trace_bio - Add a trace for a bio oriented action
760 * @q: queue the io is for
761 * @bio: the source bio
762 * @what: the action
763 * @error: error, if any
764 *
765 * Description:
766 * Records an action against a bio. Will log the bio offset + size.
767 *
768 **/
769static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
770 u32 what, int error)
771{
772 struct blk_trace *bt = q->blk_trace;
773
774 if (likely(!bt))
775 return;
776
777 if (!error && !bio_flagged(bio, BIO_UPTODATE))
778 error = EIO;
779
780 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
781 error, 0, NULL);
782}
783
784static void blk_add_trace_bio_bounce(void *ignore,
785 struct request_queue *q, struct bio *bio)
786{
787 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
788}
789
790static void blk_add_trace_bio_complete(void *ignore,
791 struct request_queue *q, struct bio *bio,
792 int error)
793{
794 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
795}
796
797static void blk_add_trace_bio_backmerge(void *ignore,
798 struct request_queue *q,
799 struct bio *bio)
800{
801 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
802}
803
804static void blk_add_trace_bio_frontmerge(void *ignore,
805 struct request_queue *q,
806 struct bio *bio)
807{
808 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
809}
810
811static void blk_add_trace_bio_queue(void *ignore,
812 struct request_queue *q, struct bio *bio)
813{
814 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
815}
816
817static void blk_add_trace_getrq(void *ignore,
818 struct request_queue *q,
819 struct bio *bio, int rw)
820{
821 if (bio)
822 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
823 else {
824 struct blk_trace *bt = q->blk_trace;
825
826 if (bt)
827 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
828 }
829}
830
831
832static void blk_add_trace_sleeprq(void *ignore,
833 struct request_queue *q,
834 struct bio *bio, int rw)
835{
836 if (bio)
837 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
838 else {
839 struct blk_trace *bt = q->blk_trace;
840
841 if (bt)
842 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
843 0, 0, NULL);
844 }
845}
846
847static void blk_add_trace_plug(void *ignore, struct request_queue *q)
848{
849 struct blk_trace *bt = q->blk_trace;
850
851 if (bt)
852 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
853}
854
855static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
856 unsigned int depth, bool explicit)
857{
858 struct blk_trace *bt = q->blk_trace;
859
860 if (bt) {
861 __be64 rpdu = cpu_to_be64(depth);
862 u32 what;
863
864 if (explicit)
865 what = BLK_TA_UNPLUG_IO;
866 else
867 what = BLK_TA_UNPLUG_TIMER;
868
869 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
870 }
871}
872
873static void blk_add_trace_split(void *ignore,
874 struct request_queue *q, struct bio *bio,
875 unsigned int pdu)
876{
877 struct blk_trace *bt = q->blk_trace;
878
879 if (bt) {
880 __be64 rpdu = cpu_to_be64(pdu);
881
882 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
883 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
884 sizeof(rpdu), &rpdu);
885 }
886}
887
888/**
889 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
890 * @ignore: trace callback data parameter (not used)
891 * @q: queue the io is for
892 * @bio: the source bio
893 * @dev: target device
894 * @from: source sector
895 *
896 * Description:
897 * Device mapper or raid target sometimes need to split a bio because
898 * it spans a stripe (or similar). Add a trace for that action.
899 *
900 **/
901static void blk_add_trace_bio_remap(void *ignore,
902 struct request_queue *q, struct bio *bio,
903 dev_t dev, sector_t from)
904{
905 struct blk_trace *bt = q->blk_trace;
906 struct blk_io_trace_remap r;
907
908 if (likely(!bt))
909 return;
910
911 r.device_from = cpu_to_be32(dev);
912 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
913 r.sector_from = cpu_to_be64(from);
914
915 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
916 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
917 sizeof(r), &r);
918}
919
920/**
921 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
922 * @ignore: trace callback data parameter (not used)
923 * @q: queue the io is for
924 * @rq: the source request
925 * @dev: target device
926 * @from: source sector
927 *
928 * Description:
929 * Device mapper remaps request to other devices.
930 * Add a trace for that action.
931 *
932 **/
933static void blk_add_trace_rq_remap(void *ignore,
934 struct request_queue *q,
935 struct request *rq, dev_t dev,
936 sector_t from)
937{
938 struct blk_trace *bt = q->blk_trace;
939 struct blk_io_trace_remap r;
940
941 if (likely(!bt))
942 return;
943
944 r.device_from = cpu_to_be32(dev);
945 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
946 r.sector_from = cpu_to_be64(from);
947
948 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
949 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
950 sizeof(r), &r);
951}
952
953/**
954 * blk_add_driver_data - Add binary message with driver-specific data
955 * @q: queue the io is for
956 * @rq: io request
957 * @data: driver-specific data
958 * @len: length of driver-specific data
959 *
960 * Description:
961 * Some drivers might want to write driver-specific data per request.
962 *
963 **/
964void blk_add_driver_data(struct request_queue *q,
965 struct request *rq,
966 void *data, size_t len)
967{
968 struct blk_trace *bt = q->blk_trace;
969
970 if (likely(!bt))
971 return;
972
973 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
974 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
975 BLK_TA_DRV_DATA, rq->errors, len, data);
976 else
977 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
978 BLK_TA_DRV_DATA, rq->errors, len, data);
979}
980EXPORT_SYMBOL_GPL(blk_add_driver_data);
981
982static void blk_register_tracepoints(void)
983{
984 int ret;
985
986 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
987 WARN_ON(ret);
988 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
989 WARN_ON(ret);
990 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
991 WARN_ON(ret);
992 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
993 WARN_ON(ret);
994 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
995 WARN_ON(ret);
996 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
997 WARN_ON(ret);
998 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
999 WARN_ON(ret);
1000 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1001 WARN_ON(ret);
1002 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1003 WARN_ON(ret);
1004 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1005 WARN_ON(ret);
1006 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1007 WARN_ON(ret);
1008 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1009 WARN_ON(ret);
1010 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1011 WARN_ON(ret);
1012 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1013 WARN_ON(ret);
1014 ret = register_trace_block_split(blk_add_trace_split, NULL);
1015 WARN_ON(ret);
1016 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1017 WARN_ON(ret);
1018 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1019 WARN_ON(ret);
1020}
1021
1022static void blk_unregister_tracepoints(void)
1023{
1024 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1025 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1026 unregister_trace_block_split(blk_add_trace_split, NULL);
1027 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1028 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1029 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1030 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1031 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1032 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1033 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1034 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1035 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1036 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1037 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1038 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1039 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1040 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1041
1042 tracepoint_synchronize_unregister();
1043}
1044
1045/*
1046 * struct blk_io_tracer formatting routines
1047 */
1048
1049static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1050{
1051 int i = 0;
1052 int tc = t->action >> BLK_TC_SHIFT;
1053
1054 if (t->action == BLK_TN_MESSAGE) {
1055 rwbs[i++] = 'N';
1056 goto out;
1057 }
1058
1059 if (tc & BLK_TC_FLUSH)
1060 rwbs[i++] = 'F';
1061
1062 if (tc & BLK_TC_DISCARD)
1063 rwbs[i++] = 'D';
1064 else if (tc & BLK_TC_WRITE)
1065 rwbs[i++] = 'W';
1066 else if (t->bytes)
1067 rwbs[i++] = 'R';
1068 else
1069 rwbs[i++] = 'N';
1070
1071 if (tc & BLK_TC_FUA)
1072 rwbs[i++] = 'F';
1073 if (tc & BLK_TC_AHEAD)
1074 rwbs[i++] = 'A';
1075 if (tc & BLK_TC_SYNC)
1076 rwbs[i++] = 'S';
1077 if (tc & BLK_TC_META)
1078 rwbs[i++] = 'M';
1079out:
1080 rwbs[i] = '\0';
1081}
1082
1083static inline
1084const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1085{
1086 return (const struct blk_io_trace *)ent;
1087}
1088
1089static inline const void *pdu_start(const struct trace_entry *ent)
1090{
1091 return te_blk_io_trace(ent) + 1;
1092}
1093
1094static inline u32 t_action(const struct trace_entry *ent)
1095{
1096 return te_blk_io_trace(ent)->action;
1097}
1098
1099static inline u32 t_bytes(const struct trace_entry *ent)
1100{
1101 return te_blk_io_trace(ent)->bytes;
1102}
1103
1104static inline u32 t_sec(const struct trace_entry *ent)
1105{
1106 return te_blk_io_trace(ent)->bytes >> 9;
1107}
1108
1109static inline unsigned long long t_sector(const struct trace_entry *ent)
1110{
1111 return te_blk_io_trace(ent)->sector;
1112}
1113
1114static inline __u16 t_error(const struct trace_entry *ent)
1115{
1116 return te_blk_io_trace(ent)->error;
1117}
1118
1119static __u64 get_pdu_int(const struct trace_entry *ent)
1120{
1121 const __u64 *val = pdu_start(ent);
1122 return be64_to_cpu(*val);
1123}
1124
1125static void get_pdu_remap(const struct trace_entry *ent,
1126 struct blk_io_trace_remap *r)
1127{
1128 const struct blk_io_trace_remap *__r = pdu_start(ent);
1129 __u64 sector_from = __r->sector_from;
1130
1131 r->device_from = be32_to_cpu(__r->device_from);
1132 r->device_to = be32_to_cpu(__r->device_to);
1133 r->sector_from = be64_to_cpu(sector_from);
1134}
1135
1136typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1137
1138static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1139{
1140 char rwbs[RWBS_LEN];
1141 unsigned long long ts = iter->ts;
1142 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1143 unsigned secs = (unsigned long)ts;
1144 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1145
1146 fill_rwbs(rwbs, t);
1147
1148 return trace_seq_printf(&iter->seq,
1149 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1150 MAJOR(t->device), MINOR(t->device), iter->cpu,
1151 secs, nsec_rem, iter->ent->pid, act, rwbs);
1152}
1153
1154static int blk_log_action(struct trace_iterator *iter, const char *act)
1155{
1156 char rwbs[RWBS_LEN];
1157 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1158
1159 fill_rwbs(rwbs, t);
1160 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1161 MAJOR(t->device), MINOR(t->device), act, rwbs);
1162}
1163
1164static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1165{
1166 const unsigned char *pdu_buf;
1167 int pdu_len;
1168 int i, end, ret;
1169
1170 pdu_buf = pdu_start(ent);
1171 pdu_len = te_blk_io_trace(ent)->pdu_len;
1172
1173 if (!pdu_len)
1174 return 1;
1175
1176 /* find the last zero that needs to be printed */
1177 for (end = pdu_len - 1; end >= 0; end--)
1178 if (pdu_buf[end])
1179 break;
1180 end++;
1181
1182 if (!trace_seq_putc(s, '('))
1183 return 0;
1184
1185 for (i = 0; i < pdu_len; i++) {
1186
1187 ret = trace_seq_printf(s, "%s%02x",
1188 i == 0 ? "" : " ", pdu_buf[i]);
1189 if (!ret)
1190 return ret;
1191
1192 /*
1193 * stop when the rest is just zeroes and indicate so
1194 * with a ".." appended
1195 */
1196 if (i == end && end != pdu_len - 1)
1197 return trace_seq_puts(s, " ..) ");
1198 }
1199
1200 return trace_seq_puts(s, ") ");
1201}
1202
1203static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1204{
1205 char cmd[TASK_COMM_LEN];
1206
1207 trace_find_cmdline(ent->pid, cmd);
1208
1209 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1210 int ret;
1211
1212 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1213 if (!ret)
1214 return 0;
1215 ret = blk_log_dump_pdu(s, ent);
1216 if (!ret)
1217 return 0;
1218 return trace_seq_printf(s, "[%s]\n", cmd);
1219 } else {
1220 if (t_sec(ent))
1221 return trace_seq_printf(s, "%llu + %u [%s]\n",
1222 t_sector(ent), t_sec(ent), cmd);
1223 return trace_seq_printf(s, "[%s]\n", cmd);
1224 }
1225}
1226
1227static int blk_log_with_error(struct trace_seq *s,
1228 const struct trace_entry *ent)
1229{
1230 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1231 int ret;
1232
1233 ret = blk_log_dump_pdu(s, ent);
1234 if (ret)
1235 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1236 return 0;
1237 } else {
1238 if (t_sec(ent))
1239 return trace_seq_printf(s, "%llu + %u [%d]\n",
1240 t_sector(ent),
1241 t_sec(ent), t_error(ent));
1242 return trace_seq_printf(s, "%llu [%d]\n",
1243 t_sector(ent), t_error(ent));
1244 }
1245}
1246
1247static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1248{
1249 struct blk_io_trace_remap r = { .device_from = 0, };
1250
1251 get_pdu_remap(ent, &r);
1252 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1253 t_sector(ent), t_sec(ent),
1254 MAJOR(r.device_from), MINOR(r.device_from),
1255 (unsigned long long)r.sector_from);
1256}
1257
1258static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1259{
1260 char cmd[TASK_COMM_LEN];
1261
1262 trace_find_cmdline(ent->pid, cmd);
1263
1264 return trace_seq_printf(s, "[%s]\n", cmd);
1265}
1266
1267static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1268{
1269 char cmd[TASK_COMM_LEN];
1270
1271 trace_find_cmdline(ent->pid, cmd);
1272
1273 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1274}
1275
1276static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1277{
1278 char cmd[TASK_COMM_LEN];
1279
1280 trace_find_cmdline(ent->pid, cmd);
1281
1282 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1283 get_pdu_int(ent), cmd);
1284}
1285
1286static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1287{
1288 int ret;
1289 const struct blk_io_trace *t = te_blk_io_trace(ent);
1290
1291 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1292 if (ret)
1293 return trace_seq_putc(s, '\n');
1294 return ret;
1295}
1296
1297/*
1298 * struct tracer operations
1299 */
1300
1301static void blk_tracer_print_header(struct seq_file *m)
1302{
1303 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1304 return;
1305 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1306 "# | | | | | |\n");
1307}
1308
1309static void blk_tracer_start(struct trace_array *tr)
1310{
1311 blk_tracer_enabled = true;
1312}
1313
1314static int blk_tracer_init(struct trace_array *tr)
1315{
1316 blk_tr = tr;
1317 blk_tracer_start(tr);
1318 return 0;
1319}
1320
1321static void blk_tracer_stop(struct trace_array *tr)
1322{
1323 blk_tracer_enabled = false;
1324}
1325
1326static void blk_tracer_reset(struct trace_array *tr)
1327{
1328 blk_tracer_stop(tr);
1329}
1330
1331static const struct {
1332 const char *act[2];
1333 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1334} what2act[] = {
1335 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1336 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1337 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1338 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1339 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1340 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1341 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1342 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1343 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1344 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1345 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1346 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1347 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1348 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1349 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1350};
1351
1352static enum print_line_t print_one_line(struct trace_iterator *iter,
1353 bool classic)
1354{
1355 struct trace_seq *s = &iter->seq;
1356 const struct blk_io_trace *t;
1357 u16 what;
1358 int ret;
1359 bool long_act;
1360 blk_log_action_t *log_action;
1361
1362 t = te_blk_io_trace(iter->ent);
1363 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1364 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1365 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1366
1367 if (t->action == BLK_TN_MESSAGE) {
1368 ret = log_action(iter, long_act ? "message" : "m");
1369 if (ret)
1370 ret = blk_log_msg(s, iter->ent);
1371 goto out;
1372 }
1373
1374 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1375 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1376 else {
1377 ret = log_action(iter, what2act[what].act[long_act]);
1378 if (ret)
1379 ret = what2act[what].print(s, iter->ent);
1380 }
1381out:
1382 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1383}
1384
1385static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1386 int flags, struct trace_event *event)
1387{
1388 return print_one_line(iter, false);
1389}
1390
1391static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1392{
1393 struct trace_seq *s = &iter->seq;
1394 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1395 const int offset = offsetof(struct blk_io_trace, sector);
1396 struct blk_io_trace old = {
1397 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1398 .time = iter->ts,
1399 };
1400
1401 if (!trace_seq_putmem(s, &old, offset))
1402 return 0;
1403 return trace_seq_putmem(s, &t->sector,
1404 sizeof(old) - offset + t->pdu_len);
1405}
1406
1407static enum print_line_t
1408blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1409 struct trace_event *event)
1410{
1411 return blk_trace_synthesize_old_trace(iter) ?
1412 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1413}
1414
1415static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1416{
1417 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1418 return TRACE_TYPE_UNHANDLED;
1419
1420 return print_one_line(iter, true);
1421}
1422
1423static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1424{
1425 /* don't output context-info for blk_classic output */
1426 if (bit == TRACE_BLK_OPT_CLASSIC) {
1427 if (set)
1428 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1429 else
1430 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1431 }
1432 return 0;
1433}
1434
1435static struct tracer blk_tracer __read_mostly = {
1436 .name = "blk",
1437 .init = blk_tracer_init,
1438 .reset = blk_tracer_reset,
1439 .start = blk_tracer_start,
1440 .stop = blk_tracer_stop,
1441 .print_header = blk_tracer_print_header,
1442 .print_line = blk_tracer_print_line,
1443 .flags = &blk_tracer_flags,
1444 .set_flag = blk_tracer_set_flag,
1445};
1446
1447static struct trace_event_functions trace_blk_event_funcs = {
1448 .trace = blk_trace_event_print,
1449 .binary = blk_trace_event_print_binary,
1450};
1451
1452static struct trace_event trace_blk_event = {
1453 .type = TRACE_BLK,
1454 .funcs = &trace_blk_event_funcs,
1455};
1456
1457static int __init init_blk_tracer(void)
1458{
1459 if (!register_ftrace_event(&trace_blk_event)) {
1460 pr_warning("Warning: could not register block events\n");
1461 return 1;
1462 }
1463
1464 if (register_tracer(&blk_tracer) != 0) {
1465 pr_warning("Warning: could not register the block tracer\n");
1466 unregister_ftrace_event(&trace_blk_event);
1467 return 1;
1468 }
1469
1470 return 0;
1471}
1472
1473device_initcall(init_blk_tracer);
1474
1475static int blk_trace_remove_queue(struct request_queue *q)
1476{
1477 struct blk_trace *bt;
1478
1479 bt = xchg(&q->blk_trace, NULL);
1480 if (bt == NULL)
1481 return -EINVAL;
1482
1483 if (atomic_dec_and_test(&blk_probes_ref))
1484 blk_unregister_tracepoints();
1485
1486 blk_trace_free(bt);
1487 return 0;
1488}
1489
1490/*
1491 * Setup everything required to start tracing
1492 */
1493static int blk_trace_setup_queue(struct request_queue *q,
1494 struct block_device *bdev)
1495{
1496 struct blk_trace *old_bt, *bt = NULL;
1497 int ret = -ENOMEM;
1498
1499 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1500 if (!bt)
1501 return -ENOMEM;
1502
1503 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1504 if (!bt->msg_data)
1505 goto free_bt;
1506
1507 bt->dev = bdev->bd_dev;
1508 bt->act_mask = (u16)-1;
1509
1510 blk_trace_setup_lba(bt, bdev);
1511
1512 old_bt = xchg(&q->blk_trace, bt);
1513 if (old_bt != NULL) {
1514 (void)xchg(&q->blk_trace, old_bt);
1515 ret = -EBUSY;
1516 goto free_bt;
1517 }
1518
1519 if (atomic_inc_return(&blk_probes_ref) == 1)
1520 blk_register_tracepoints();
1521 return 0;
1522
1523free_bt:
1524 blk_trace_free(bt);
1525 return ret;
1526}
1527
1528/*
1529 * sysfs interface to enable and configure tracing
1530 */
1531
1532static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1533 struct device_attribute *attr,
1534 char *buf);
1535static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1536 struct device_attribute *attr,
1537 const char *buf, size_t count);
1538#define BLK_TRACE_DEVICE_ATTR(_name) \
1539 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1540 sysfs_blk_trace_attr_show, \
1541 sysfs_blk_trace_attr_store)
1542
1543static BLK_TRACE_DEVICE_ATTR(enable);
1544static BLK_TRACE_DEVICE_ATTR(act_mask);
1545static BLK_TRACE_DEVICE_ATTR(pid);
1546static BLK_TRACE_DEVICE_ATTR(start_lba);
1547static BLK_TRACE_DEVICE_ATTR(end_lba);
1548
1549static struct attribute *blk_trace_attrs[] = {
1550 &dev_attr_enable.attr,
1551 &dev_attr_act_mask.attr,
1552 &dev_attr_pid.attr,
1553 &dev_attr_start_lba.attr,
1554 &dev_attr_end_lba.attr,
1555 NULL
1556};
1557
1558struct attribute_group blk_trace_attr_group = {
1559 .name = "trace",
1560 .attrs = blk_trace_attrs,
1561};
1562
1563static const struct {
1564 int mask;
1565 const char *str;
1566} mask_maps[] = {
1567 { BLK_TC_READ, "read" },
1568 { BLK_TC_WRITE, "write" },
1569 { BLK_TC_FLUSH, "flush" },
1570 { BLK_TC_SYNC, "sync" },
1571 { BLK_TC_QUEUE, "queue" },
1572 { BLK_TC_REQUEUE, "requeue" },
1573 { BLK_TC_ISSUE, "issue" },
1574 { BLK_TC_COMPLETE, "complete" },
1575 { BLK_TC_FS, "fs" },
1576 { BLK_TC_PC, "pc" },
1577 { BLK_TC_AHEAD, "ahead" },
1578 { BLK_TC_META, "meta" },
1579 { BLK_TC_DISCARD, "discard" },
1580 { BLK_TC_DRV_DATA, "drv_data" },
1581 { BLK_TC_FUA, "fua" },
1582};
1583
1584static int blk_trace_str2mask(const char *str)
1585{
1586 int i;
1587 int mask = 0;
1588 char *buf, *s, *token;
1589
1590 buf = kstrdup(str, GFP_KERNEL);
1591 if (buf == NULL)
1592 return -ENOMEM;
1593 s = strstrip(buf);
1594
1595 while (1) {
1596 token = strsep(&s, ",");
1597 if (token == NULL)
1598 break;
1599
1600 if (*token == '\0')
1601 continue;
1602
1603 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1604 if (strcasecmp(token, mask_maps[i].str) == 0) {
1605 mask |= mask_maps[i].mask;
1606 break;
1607 }
1608 }
1609 if (i == ARRAY_SIZE(mask_maps)) {
1610 mask = -EINVAL;
1611 break;
1612 }
1613 }
1614 kfree(buf);
1615
1616 return mask;
1617}
1618
1619static ssize_t blk_trace_mask2str(char *buf, int mask)
1620{
1621 int i;
1622 char *p = buf;
1623
1624 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1625 if (mask & mask_maps[i].mask) {
1626 p += sprintf(p, "%s%s",
1627 (p == buf) ? "" : ",", mask_maps[i].str);
1628 }
1629 }
1630 *p++ = '\n';
1631
1632 return p - buf;
1633}
1634
1635static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1636{
1637 if (bdev->bd_disk == NULL)
1638 return NULL;
1639
1640 return bdev_get_queue(bdev);
1641}
1642
1643static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1644 struct device_attribute *attr,
1645 char *buf)
1646{
1647 struct hd_struct *p = dev_to_part(dev);
1648 struct request_queue *q;
1649 struct block_device *bdev;
1650 ssize_t ret = -ENXIO;
1651
1652 bdev = bdget(part_devt(p));
1653 if (bdev == NULL)
1654 goto out;
1655
1656 q = blk_trace_get_queue(bdev);
1657 if (q == NULL)
1658 goto out_bdput;
1659
1660 mutex_lock(&bdev->bd_mutex);
1661
1662 if (attr == &dev_attr_enable) {
1663 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1664 goto out_unlock_bdev;
1665 }
1666
1667 if (q->blk_trace == NULL)
1668 ret = sprintf(buf, "disabled\n");
1669 else if (attr == &dev_attr_act_mask)
1670 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1671 else if (attr == &dev_attr_pid)
1672 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1673 else if (attr == &dev_attr_start_lba)
1674 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1675 else if (attr == &dev_attr_end_lba)
1676 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1677
1678out_unlock_bdev:
1679 mutex_unlock(&bdev->bd_mutex);
1680out_bdput:
1681 bdput(bdev);
1682out:
1683 return ret;
1684}
1685
1686static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1687 struct device_attribute *attr,
1688 const char *buf, size_t count)
1689{
1690 struct block_device *bdev;
1691 struct request_queue *q;
1692 struct hd_struct *p;
1693 u64 value;
1694 ssize_t ret = -EINVAL;
1695
1696 if (count == 0)
1697 goto out;
1698
1699 if (attr == &dev_attr_act_mask) {
1700 if (sscanf(buf, "%llx", &value) != 1) {
1701 /* Assume it is a list of trace category names */
1702 ret = blk_trace_str2mask(buf);
1703 if (ret < 0)
1704 goto out;
1705 value = ret;
1706 }
1707 } else if (sscanf(buf, "%llu", &value) != 1)
1708 goto out;
1709
1710 ret = -ENXIO;
1711
1712 p = dev_to_part(dev);
1713 bdev = bdget(part_devt(p));
1714 if (bdev == NULL)
1715 goto out;
1716
1717 q = blk_trace_get_queue(bdev);
1718 if (q == NULL)
1719 goto out_bdput;
1720
1721 mutex_lock(&bdev->bd_mutex);
1722
1723 if (attr == &dev_attr_enable) {
1724 if (value)
1725 ret = blk_trace_setup_queue(q, bdev);
1726 else
1727 ret = blk_trace_remove_queue(q);
1728 goto out_unlock_bdev;
1729 }
1730
1731 ret = 0;
1732 if (q->blk_trace == NULL)
1733 ret = blk_trace_setup_queue(q, bdev);
1734
1735 if (ret == 0) {
1736 if (attr == &dev_attr_act_mask)
1737 q->blk_trace->act_mask = value;
1738 else if (attr == &dev_attr_pid)
1739 q->blk_trace->pid = value;
1740 else if (attr == &dev_attr_start_lba)
1741 q->blk_trace->start_lba = value;
1742 else if (attr == &dev_attr_end_lba)
1743 q->blk_trace->end_lba = value;
1744 }
1745
1746out_unlock_bdev:
1747 mutex_unlock(&bdev->bd_mutex);
1748out_bdput:
1749 bdput(bdev);
1750out:
1751 return ret ? ret : count;
1752}
1753
1754int blk_trace_init_sysfs(struct device *dev)
1755{
1756 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1757}
1758
1759void blk_trace_remove_sysfs(struct device *dev)
1760{
1761 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1762}
1763
1764#endif /* CONFIG_BLK_DEV_IO_TRACE */
1765
1766#ifdef CONFIG_EVENT_TRACING
1767
1768void blk_dump_cmd(char *buf, struct request *rq)
1769{
1770 int i, end;
1771 int len = rq->cmd_len;
1772 unsigned char *cmd = rq->cmd;
1773
1774 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1775 buf[0] = '\0';
1776 return;
1777 }
1778
1779 for (end = len - 1; end >= 0; end--)
1780 if (cmd[end])
1781 break;
1782 end++;
1783
1784 for (i = 0; i < len; i++) {
1785 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1786 if (i == end && end != len - 1) {
1787 sprintf(buf, " ..");
1788 break;
1789 }
1790 }
1791}
1792
1793void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1794{
1795 int i = 0;
1796
1797 if (rw & REQ_FLUSH)
1798 rwbs[i++] = 'F';
1799
1800 if (rw & WRITE)
1801 rwbs[i++] = 'W';
1802 else if (rw & REQ_DISCARD)
1803 rwbs[i++] = 'D';
1804 else if (bytes)
1805 rwbs[i++] = 'R';
1806 else
1807 rwbs[i++] = 'N';
1808
1809 if (rw & REQ_FUA)
1810 rwbs[i++] = 'F';
1811 if (rw & REQ_RAHEAD)
1812 rwbs[i++] = 'A';
1813 if (rw & REQ_SYNC)
1814 rwbs[i++] = 'S';
1815 if (rw & REQ_META)
1816 rwbs[i++] = 'M';
1817 if (rw & REQ_SECURE)
1818 rwbs[i++] = 'E';
1819
1820 rwbs[i] = '\0';
1821}
1822
1823#endif /* CONFIG_EVENT_TRACING */
1824