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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland...
[deliverable/linux.git] / kernel / trace / blktrace.c
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/smp_lock.h>
27 #include <linux/time.h>
28 #include <linux/uaccess.h>
29
30 #include <trace/events/block.h>
31
32 #include "trace_output.h"
33
34 #ifdef CONFIG_BLK_DEV_IO_TRACE
35
36 static unsigned int blktrace_seq __read_mostly = 1;
37
38 static struct trace_array *blk_tr;
39 static bool blk_tracer_enabled __read_mostly;
40
41 /* Select an alternative, minimalistic output than the original one */
42 #define TRACE_BLK_OPT_CLASSIC 0x1
43
44 static struct tracer_opt blk_tracer_opts[] = {
45 /* Default disable the minimalistic output */
46 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
47 { }
48 };
49
50 static struct tracer_flags blk_tracer_flags = {
51 .val = 0,
52 .opts = blk_tracer_opts,
53 };
54
55 /* Global reference count of probes */
56 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
57
58 static void blk_register_tracepoints(void);
59 static void blk_unregister_tracepoints(void);
60
61 /*
62 * Send out a notify message.
63 */
64 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
65 const void *data, size_t len)
66 {
67 struct blk_io_trace *t;
68 struct ring_buffer_event *event = NULL;
69 struct ring_buffer *buffer = NULL;
70 int pc = 0;
71 int cpu = smp_processor_id();
72 bool blk_tracer = blk_tracer_enabled;
73
74 if (blk_tracer) {
75 buffer = blk_tr->buffer;
76 pc = preempt_count();
77 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
78 sizeof(*t) + len,
79 0, pc);
80 if (!event)
81 return;
82 t = ring_buffer_event_data(event);
83 goto record_it;
84 }
85
86 if (!bt->rchan)
87 return;
88
89 t = relay_reserve(bt->rchan, sizeof(*t) + len);
90 if (t) {
91 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
92 t->time = ktime_to_ns(ktime_get());
93 record_it:
94 t->device = bt->dev;
95 t->action = action;
96 t->pid = pid;
97 t->cpu = cpu;
98 t->pdu_len = len;
99 memcpy((void *) t + sizeof(*t), data, len);
100
101 if (blk_tracer)
102 trace_buffer_unlock_commit(buffer, event, 0, pc);
103 }
104 }
105
106 /*
107 * Send out a notify for this process, if we haven't done so since a trace
108 * started
109 */
110 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
111 {
112 tsk->btrace_seq = blktrace_seq;
113 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
114 }
115
116 static void trace_note_time(struct blk_trace *bt)
117 {
118 struct timespec now;
119 unsigned long flags;
120 u32 words[2];
121
122 getnstimeofday(&now);
123 words[0] = now.tv_sec;
124 words[1] = now.tv_nsec;
125
126 local_irq_save(flags);
127 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
128 local_irq_restore(flags);
129 }
130
131 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
132 {
133 int n;
134 va_list args;
135 unsigned long flags;
136 char *buf;
137
138 if (unlikely(bt->trace_state != Blktrace_running &&
139 !blk_tracer_enabled))
140 return;
141
142 local_irq_save(flags);
143 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
144 va_start(args, fmt);
145 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
146 va_end(args);
147
148 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
149 local_irq_restore(flags);
150 }
151 EXPORT_SYMBOL_GPL(__trace_note_message);
152
153 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
154 pid_t pid)
155 {
156 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
157 return 1;
158 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
159 return 1;
160 if (bt->pid && pid != bt->pid)
161 return 1;
162
163 return 0;
164 }
165
166 /*
167 * Data direction bit lookup
168 */
169 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
170 BLK_TC_ACT(BLK_TC_WRITE) };
171
172 /* The ilog2() calls fall out because they're constant */
173 #define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
174 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name))
175
176 /*
177 * The worker for the various blk_add_trace*() types. Fills out a
178 * blk_io_trace structure and places it in a per-cpu subbuffer.
179 */
180 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
181 int rw, u32 what, int error, int pdu_len, void *pdu_data)
182 {
183 struct task_struct *tsk = current;
184 struct ring_buffer_event *event = NULL;
185 struct ring_buffer *buffer = NULL;
186 struct blk_io_trace *t;
187 unsigned long flags = 0;
188 unsigned long *sequence;
189 pid_t pid;
190 int cpu, pc = 0;
191 bool blk_tracer = blk_tracer_enabled;
192
193 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
194 return;
195
196 what |= ddir_act[rw & WRITE];
197 what |= MASK_TC_BIT(rw, BARRIER);
198 what |= MASK_TC_BIT(rw, SYNCIO);
199 what |= MASK_TC_BIT(rw, AHEAD);
200 what |= MASK_TC_BIT(rw, META);
201 what |= MASK_TC_BIT(rw, DISCARD);
202
203 pid = tsk->pid;
204 if (act_log_check(bt, what, sector, pid))
205 return;
206 cpu = raw_smp_processor_id();
207
208 if (blk_tracer) {
209 tracing_record_cmdline(current);
210
211 buffer = blk_tr->buffer;
212 pc = preempt_count();
213 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
214 sizeof(*t) + pdu_len,
215 0, pc);
216 if (!event)
217 return;
218 t = ring_buffer_event_data(event);
219 goto record_it;
220 }
221
222 /*
223 * A word about the locking here - we disable interrupts to reserve
224 * some space in the relay per-cpu buffer, to prevent an irq
225 * from coming in and stepping on our toes.
226 */
227 local_irq_save(flags);
228
229 if (unlikely(tsk->btrace_seq != blktrace_seq))
230 trace_note_tsk(bt, tsk);
231
232 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
233 if (t) {
234 sequence = per_cpu_ptr(bt->sequence, cpu);
235
236 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
237 t->sequence = ++(*sequence);
238 t->time = ktime_to_ns(ktime_get());
239 record_it:
240 /*
241 * These two are not needed in ftrace as they are in the
242 * generic trace_entry, filled by tracing_generic_entry_update,
243 * but for the trace_event->bin() synthesizer benefit we do it
244 * here too.
245 */
246 t->cpu = cpu;
247 t->pid = pid;
248
249 t->sector = sector;
250 t->bytes = bytes;
251 t->action = what;
252 t->device = bt->dev;
253 t->error = error;
254 t->pdu_len = pdu_len;
255
256 if (pdu_len)
257 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
258
259 if (blk_tracer) {
260 trace_buffer_unlock_commit(buffer, event, 0, pc);
261 return;
262 }
263 }
264
265 local_irq_restore(flags);
266 }
267
268 static struct dentry *blk_tree_root;
269 static DEFINE_MUTEX(blk_tree_mutex);
270
271 static void blk_trace_free(struct blk_trace *bt)
272 {
273 debugfs_remove(bt->msg_file);
274 debugfs_remove(bt->dropped_file);
275 relay_close(bt->rchan);
276 debugfs_remove(bt->dir);
277 free_percpu(bt->sequence);
278 free_percpu(bt->msg_data);
279 kfree(bt);
280 }
281
282 static void blk_trace_cleanup(struct blk_trace *bt)
283 {
284 blk_trace_free(bt);
285 if (atomic_dec_and_test(&blk_probes_ref))
286 blk_unregister_tracepoints();
287 }
288
289 int blk_trace_remove(struct request_queue *q)
290 {
291 struct blk_trace *bt;
292
293 bt = xchg(&q->blk_trace, NULL);
294 if (!bt)
295 return -EINVAL;
296
297 if (bt->trace_state != Blktrace_running)
298 blk_trace_cleanup(bt);
299
300 return 0;
301 }
302 EXPORT_SYMBOL_GPL(blk_trace_remove);
303
304 static int blk_dropped_open(struct inode *inode, struct file *filp)
305 {
306 filp->private_data = inode->i_private;
307
308 return 0;
309 }
310
311 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
312 size_t count, loff_t *ppos)
313 {
314 struct blk_trace *bt = filp->private_data;
315 char buf[16];
316
317 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
318
319 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
320 }
321
322 static const struct file_operations blk_dropped_fops = {
323 .owner = THIS_MODULE,
324 .open = blk_dropped_open,
325 .read = blk_dropped_read,
326 };
327
328 static int blk_msg_open(struct inode *inode, struct file *filp)
329 {
330 filp->private_data = inode->i_private;
331
332 return 0;
333 }
334
335 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
336 size_t count, loff_t *ppos)
337 {
338 char *msg;
339 struct blk_trace *bt;
340
341 if (count >= BLK_TN_MAX_MSG)
342 return -EINVAL;
343
344 msg = kmalloc(count + 1, GFP_KERNEL);
345 if (msg == NULL)
346 return -ENOMEM;
347
348 if (copy_from_user(msg, buffer, count)) {
349 kfree(msg);
350 return -EFAULT;
351 }
352
353 msg[count] = '\0';
354 bt = filp->private_data;
355 __trace_note_message(bt, "%s", msg);
356 kfree(msg);
357
358 return count;
359 }
360
361 static const struct file_operations blk_msg_fops = {
362 .owner = THIS_MODULE,
363 .open = blk_msg_open,
364 .write = blk_msg_write,
365 };
366
367 /*
368 * Keep track of how many times we encountered a full subbuffer, to aid
369 * the user space app in telling how many lost events there were.
370 */
371 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
372 void *prev_subbuf, size_t prev_padding)
373 {
374 struct blk_trace *bt;
375
376 if (!relay_buf_full(buf))
377 return 1;
378
379 bt = buf->chan->private_data;
380 atomic_inc(&bt->dropped);
381 return 0;
382 }
383
384 static int blk_remove_buf_file_callback(struct dentry *dentry)
385 {
386 debugfs_remove(dentry);
387
388 return 0;
389 }
390
391 static struct dentry *blk_create_buf_file_callback(const char *filename,
392 struct dentry *parent,
393 int mode,
394 struct rchan_buf *buf,
395 int *is_global)
396 {
397 return debugfs_create_file(filename, mode, parent, buf,
398 &relay_file_operations);
399 }
400
401 static struct rchan_callbacks blk_relay_callbacks = {
402 .subbuf_start = blk_subbuf_start_callback,
403 .create_buf_file = blk_create_buf_file_callback,
404 .remove_buf_file = blk_remove_buf_file_callback,
405 };
406
407 static void blk_trace_setup_lba(struct blk_trace *bt,
408 struct block_device *bdev)
409 {
410 struct hd_struct *part = NULL;
411
412 if (bdev)
413 part = bdev->bd_part;
414
415 if (part) {
416 bt->start_lba = part->start_sect;
417 bt->end_lba = part->start_sect + part->nr_sects;
418 } else {
419 bt->start_lba = 0;
420 bt->end_lba = -1ULL;
421 }
422 }
423
424 /*
425 * Setup everything required to start tracing
426 */
427 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
428 struct block_device *bdev,
429 struct blk_user_trace_setup *buts)
430 {
431 struct blk_trace *old_bt, *bt = NULL;
432 struct dentry *dir = NULL;
433 int ret, i;
434
435 if (!buts->buf_size || !buts->buf_nr)
436 return -EINVAL;
437
438 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
439 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
440
441 /*
442 * some device names have larger paths - convert the slashes
443 * to underscores for this to work as expected
444 */
445 for (i = 0; i < strlen(buts->name); i++)
446 if (buts->name[i] == '/')
447 buts->name[i] = '_';
448
449 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
450 if (!bt)
451 return -ENOMEM;
452
453 ret = -ENOMEM;
454 bt->sequence = alloc_percpu(unsigned long);
455 if (!bt->sequence)
456 goto err;
457
458 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
459 if (!bt->msg_data)
460 goto err;
461
462 ret = -ENOENT;
463
464 mutex_lock(&blk_tree_mutex);
465 if (!blk_tree_root) {
466 blk_tree_root = debugfs_create_dir("block", NULL);
467 if (!blk_tree_root) {
468 mutex_unlock(&blk_tree_mutex);
469 goto err;
470 }
471 }
472 mutex_unlock(&blk_tree_mutex);
473
474 dir = debugfs_create_dir(buts->name, blk_tree_root);
475
476 if (!dir)
477 goto err;
478
479 bt->dir = dir;
480 bt->dev = dev;
481 atomic_set(&bt->dropped, 0);
482
483 ret = -EIO;
484 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
485 &blk_dropped_fops);
486 if (!bt->dropped_file)
487 goto err;
488
489 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
490 if (!bt->msg_file)
491 goto err;
492
493 bt->rchan = relay_open("trace", dir, buts->buf_size,
494 buts->buf_nr, &blk_relay_callbacks, bt);
495 if (!bt->rchan)
496 goto err;
497
498 bt->act_mask = buts->act_mask;
499 if (!bt->act_mask)
500 bt->act_mask = (u16) -1;
501
502 blk_trace_setup_lba(bt, bdev);
503
504 /* overwrite with user settings */
505 if (buts->start_lba)
506 bt->start_lba = buts->start_lba;
507 if (buts->end_lba)
508 bt->end_lba = buts->end_lba;
509
510 bt->pid = buts->pid;
511 bt->trace_state = Blktrace_setup;
512
513 ret = -EBUSY;
514 old_bt = xchg(&q->blk_trace, bt);
515 if (old_bt) {
516 (void) xchg(&q->blk_trace, old_bt);
517 goto err;
518 }
519
520 if (atomic_inc_return(&blk_probes_ref) == 1)
521 blk_register_tracepoints();
522
523 return 0;
524 err:
525 blk_trace_free(bt);
526 return ret;
527 }
528
529 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
530 struct block_device *bdev,
531 char __user *arg)
532 {
533 struct blk_user_trace_setup buts;
534 int ret;
535
536 ret = copy_from_user(&buts, arg, sizeof(buts));
537 if (ret)
538 return -EFAULT;
539
540 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
541 if (ret)
542 return ret;
543
544 if (copy_to_user(arg, &buts, sizeof(buts))) {
545 blk_trace_remove(q);
546 return -EFAULT;
547 }
548 return 0;
549 }
550 EXPORT_SYMBOL_GPL(blk_trace_setup);
551
552 int blk_trace_startstop(struct request_queue *q, int start)
553 {
554 int ret;
555 struct blk_trace *bt = q->blk_trace;
556
557 if (bt == NULL)
558 return -EINVAL;
559
560 /*
561 * For starting a trace, we can transition from a setup or stopped
562 * trace. For stopping a trace, the state must be running
563 */
564 ret = -EINVAL;
565 if (start) {
566 if (bt->trace_state == Blktrace_setup ||
567 bt->trace_state == Blktrace_stopped) {
568 blktrace_seq++;
569 smp_mb();
570 bt->trace_state = Blktrace_running;
571
572 trace_note_time(bt);
573 ret = 0;
574 }
575 } else {
576 if (bt->trace_state == Blktrace_running) {
577 bt->trace_state = Blktrace_stopped;
578 relay_flush(bt->rchan);
579 ret = 0;
580 }
581 }
582
583 return ret;
584 }
585 EXPORT_SYMBOL_GPL(blk_trace_startstop);
586
587 /**
588 * blk_trace_ioctl: - handle the ioctls associated with tracing
589 * @bdev: the block device
590 * @cmd: the ioctl cmd
591 * @arg: the argument data, if any
592 *
593 **/
594 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
595 {
596 struct request_queue *q;
597 int ret, start = 0;
598 char b[BDEVNAME_SIZE];
599
600 q = bdev_get_queue(bdev);
601 if (!q)
602 return -ENXIO;
603
604 mutex_lock(&bdev->bd_mutex);
605
606 switch (cmd) {
607 case BLKTRACESETUP:
608 bdevname(bdev, b);
609 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
610 break;
611 case BLKTRACESTART:
612 start = 1;
613 case BLKTRACESTOP:
614 ret = blk_trace_startstop(q, start);
615 break;
616 case BLKTRACETEARDOWN:
617 ret = blk_trace_remove(q);
618 break;
619 default:
620 ret = -ENOTTY;
621 break;
622 }
623
624 mutex_unlock(&bdev->bd_mutex);
625 return ret;
626 }
627
628 /**
629 * blk_trace_shutdown: - stop and cleanup trace structures
630 * @q: the request queue associated with the device
631 *
632 **/
633 void blk_trace_shutdown(struct request_queue *q)
634 {
635 if (q->blk_trace) {
636 blk_trace_startstop(q, 0);
637 blk_trace_remove(q);
638 }
639 }
640
641 /*
642 * blktrace probes
643 */
644
645 /**
646 * blk_add_trace_rq - Add a trace for a request oriented action
647 * @q: queue the io is for
648 * @rq: the source request
649 * @what: the action
650 *
651 * Description:
652 * Records an action against a request. Will log the bio offset + size.
653 *
654 **/
655 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
656 u32 what)
657 {
658 struct blk_trace *bt = q->blk_trace;
659 int rw = rq->cmd_flags & 0x03;
660
661 if (likely(!bt))
662 return;
663
664 if (blk_discard_rq(rq))
665 rw |= (1 << BIO_RW_DISCARD);
666
667 if (blk_pc_request(rq)) {
668 what |= BLK_TC_ACT(BLK_TC_PC);
669 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
670 what, rq->errors, rq->cmd_len, rq->cmd);
671 } else {
672 what |= BLK_TC_ACT(BLK_TC_FS);
673 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
674 what, rq->errors, 0, NULL);
675 }
676 }
677
678 static void blk_add_trace_rq_abort(void *ignore,
679 struct request_queue *q, struct request *rq)
680 {
681 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
682 }
683
684 static void blk_add_trace_rq_insert(void *ignore,
685 struct request_queue *q, struct request *rq)
686 {
687 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
688 }
689
690 static void blk_add_trace_rq_issue(void *ignore,
691 struct request_queue *q, struct request *rq)
692 {
693 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
694 }
695
696 static void blk_add_trace_rq_requeue(void *ignore,
697 struct request_queue *q,
698 struct request *rq)
699 {
700 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
701 }
702
703 static void blk_add_trace_rq_complete(void *ignore,
704 struct request_queue *q,
705 struct request *rq)
706 {
707 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
708 }
709
710 /**
711 * blk_add_trace_bio - Add a trace for a bio oriented action
712 * @q: queue the io is for
713 * @bio: the source bio
714 * @what: the action
715 *
716 * Description:
717 * Records an action against a bio. Will log the bio offset + size.
718 *
719 **/
720 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
721 u32 what)
722 {
723 struct blk_trace *bt = q->blk_trace;
724
725 if (likely(!bt))
726 return;
727
728 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
729 !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
730 }
731
732 static void blk_add_trace_bio_bounce(void *ignore,
733 struct request_queue *q, struct bio *bio)
734 {
735 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
736 }
737
738 static void blk_add_trace_bio_complete(void *ignore,
739 struct request_queue *q, struct bio *bio)
740 {
741 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
742 }
743
744 static void blk_add_trace_bio_backmerge(void *ignore,
745 struct request_queue *q,
746 struct bio *bio)
747 {
748 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
749 }
750
751 static void blk_add_trace_bio_frontmerge(void *ignore,
752 struct request_queue *q,
753 struct bio *bio)
754 {
755 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
756 }
757
758 static void blk_add_trace_bio_queue(void *ignore,
759 struct request_queue *q, struct bio *bio)
760 {
761 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
762 }
763
764 static void blk_add_trace_getrq(void *ignore,
765 struct request_queue *q,
766 struct bio *bio, int rw)
767 {
768 if (bio)
769 blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
770 else {
771 struct blk_trace *bt = q->blk_trace;
772
773 if (bt)
774 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
775 }
776 }
777
778
779 static void blk_add_trace_sleeprq(void *ignore,
780 struct request_queue *q,
781 struct bio *bio, int rw)
782 {
783 if (bio)
784 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
785 else {
786 struct blk_trace *bt = q->blk_trace;
787
788 if (bt)
789 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
790 0, 0, NULL);
791 }
792 }
793
794 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
795 {
796 struct blk_trace *bt = q->blk_trace;
797
798 if (bt)
799 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
800 }
801
802 static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q)
803 {
804 struct blk_trace *bt = q->blk_trace;
805
806 if (bt) {
807 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
808 __be64 rpdu = cpu_to_be64(pdu);
809
810 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
811 sizeof(rpdu), &rpdu);
812 }
813 }
814
815 static void blk_add_trace_unplug_timer(void *ignore, struct request_queue *q)
816 {
817 struct blk_trace *bt = q->blk_trace;
818
819 if (bt) {
820 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
821 __be64 rpdu = cpu_to_be64(pdu);
822
823 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
824 sizeof(rpdu), &rpdu);
825 }
826 }
827
828 static void blk_add_trace_split(void *ignore,
829 struct request_queue *q, struct bio *bio,
830 unsigned int pdu)
831 {
832 struct blk_trace *bt = q->blk_trace;
833
834 if (bt) {
835 __be64 rpdu = cpu_to_be64(pdu);
836
837 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
838 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
839 sizeof(rpdu), &rpdu);
840 }
841 }
842
843 /**
844 * blk_add_trace_remap - Add a trace for a remap operation
845 * @q: queue the io is for
846 * @bio: the source bio
847 * @dev: target device
848 * @from: source sector
849 *
850 * Description:
851 * Device mapper or raid target sometimes need to split a bio because
852 * it spans a stripe (or similar). Add a trace for that action.
853 *
854 **/
855 static void blk_add_trace_remap(void *ignore,
856 struct request_queue *q, struct bio *bio,
857 dev_t dev, sector_t from)
858 {
859 struct blk_trace *bt = q->blk_trace;
860 struct blk_io_trace_remap r;
861
862 if (likely(!bt))
863 return;
864
865 r.device_from = cpu_to_be32(dev);
866 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
867 r.sector_from = cpu_to_be64(from);
868
869 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
870 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
871 sizeof(r), &r);
872 }
873
874 /**
875 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
876 * @q: queue the io is for
877 * @rq: the source request
878 * @dev: target device
879 * @from: source sector
880 *
881 * Description:
882 * Device mapper remaps request to other devices.
883 * Add a trace for that action.
884 *
885 **/
886 static void blk_add_trace_rq_remap(void *ignore,
887 struct request_queue *q,
888 struct request *rq, dev_t dev,
889 sector_t from)
890 {
891 struct blk_trace *bt = q->blk_trace;
892 struct blk_io_trace_remap r;
893
894 if (likely(!bt))
895 return;
896
897 r.device_from = cpu_to_be32(dev);
898 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
899 r.sector_from = cpu_to_be64(from);
900
901 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
902 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
903 sizeof(r), &r);
904 }
905
906 /**
907 * blk_add_driver_data - Add binary message with driver-specific data
908 * @q: queue the io is for
909 * @rq: io request
910 * @data: driver-specific data
911 * @len: length of driver-specific data
912 *
913 * Description:
914 * Some drivers might want to write driver-specific data per request.
915 *
916 **/
917 void blk_add_driver_data(struct request_queue *q,
918 struct request *rq,
919 void *data, size_t len)
920 {
921 struct blk_trace *bt = q->blk_trace;
922
923 if (likely(!bt))
924 return;
925
926 if (blk_pc_request(rq))
927 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
928 BLK_TA_DRV_DATA, rq->errors, len, data);
929 else
930 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
931 BLK_TA_DRV_DATA, rq->errors, len, data);
932 }
933 EXPORT_SYMBOL_GPL(blk_add_driver_data);
934
935 static void blk_register_tracepoints(void)
936 {
937 int ret;
938
939 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
940 WARN_ON(ret);
941 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
942 WARN_ON(ret);
943 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
944 WARN_ON(ret);
945 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
946 WARN_ON(ret);
947 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
948 WARN_ON(ret);
949 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
950 WARN_ON(ret);
951 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
952 WARN_ON(ret);
953 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
954 WARN_ON(ret);
955 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
956 WARN_ON(ret);
957 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
958 WARN_ON(ret);
959 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
960 WARN_ON(ret);
961 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
962 WARN_ON(ret);
963 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
964 WARN_ON(ret);
965 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
966 WARN_ON(ret);
967 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
968 WARN_ON(ret);
969 ret = register_trace_block_split(blk_add_trace_split, NULL);
970 WARN_ON(ret);
971 ret = register_trace_block_remap(blk_add_trace_remap, NULL);
972 WARN_ON(ret);
973 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
974 WARN_ON(ret);
975 }
976
977 static void blk_unregister_tracepoints(void)
978 {
979 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
980 unregister_trace_block_remap(blk_add_trace_remap, NULL);
981 unregister_trace_block_split(blk_add_trace_split, NULL);
982 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
983 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
984 unregister_trace_block_plug(blk_add_trace_plug, NULL);
985 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
986 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
987 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
988 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
989 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
990 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
991 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
992 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
993 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
994 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
995 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
996 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
997
998 tracepoint_synchronize_unregister();
999 }
1000
1001 /*
1002 * struct blk_io_tracer formatting routines
1003 */
1004
1005 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1006 {
1007 int i = 0;
1008 int tc = t->action >> BLK_TC_SHIFT;
1009
1010 if (t->action == BLK_TN_MESSAGE) {
1011 rwbs[i++] = 'N';
1012 goto out;
1013 }
1014
1015 if (tc & BLK_TC_DISCARD)
1016 rwbs[i++] = 'D';
1017 else if (tc & BLK_TC_WRITE)
1018 rwbs[i++] = 'W';
1019 else if (t->bytes)
1020 rwbs[i++] = 'R';
1021 else
1022 rwbs[i++] = 'N';
1023
1024 if (tc & BLK_TC_AHEAD)
1025 rwbs[i++] = 'A';
1026 if (tc & BLK_TC_BARRIER)
1027 rwbs[i++] = 'B';
1028 if (tc & BLK_TC_SYNC)
1029 rwbs[i++] = 'S';
1030 if (tc & BLK_TC_META)
1031 rwbs[i++] = 'M';
1032 out:
1033 rwbs[i] = '\0';
1034 }
1035
1036 static inline
1037 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1038 {
1039 return (const struct blk_io_trace *)ent;
1040 }
1041
1042 static inline const void *pdu_start(const struct trace_entry *ent)
1043 {
1044 return te_blk_io_trace(ent) + 1;
1045 }
1046
1047 static inline u32 t_action(const struct trace_entry *ent)
1048 {
1049 return te_blk_io_trace(ent)->action;
1050 }
1051
1052 static inline u32 t_bytes(const struct trace_entry *ent)
1053 {
1054 return te_blk_io_trace(ent)->bytes;
1055 }
1056
1057 static inline u32 t_sec(const struct trace_entry *ent)
1058 {
1059 return te_blk_io_trace(ent)->bytes >> 9;
1060 }
1061
1062 static inline unsigned long long t_sector(const struct trace_entry *ent)
1063 {
1064 return te_blk_io_trace(ent)->sector;
1065 }
1066
1067 static inline __u16 t_error(const struct trace_entry *ent)
1068 {
1069 return te_blk_io_trace(ent)->error;
1070 }
1071
1072 static __u64 get_pdu_int(const struct trace_entry *ent)
1073 {
1074 const __u64 *val = pdu_start(ent);
1075 return be64_to_cpu(*val);
1076 }
1077
1078 static void get_pdu_remap(const struct trace_entry *ent,
1079 struct blk_io_trace_remap *r)
1080 {
1081 const struct blk_io_trace_remap *__r = pdu_start(ent);
1082 __u64 sector_from = __r->sector_from;
1083
1084 r->device_from = be32_to_cpu(__r->device_from);
1085 r->device_to = be32_to_cpu(__r->device_to);
1086 r->sector_from = be64_to_cpu(sector_from);
1087 }
1088
1089 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1090
1091 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1092 {
1093 char rwbs[6];
1094 unsigned long long ts = iter->ts;
1095 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1096 unsigned secs = (unsigned long)ts;
1097 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1098
1099 fill_rwbs(rwbs, t);
1100
1101 return trace_seq_printf(&iter->seq,
1102 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1103 MAJOR(t->device), MINOR(t->device), iter->cpu,
1104 secs, nsec_rem, iter->ent->pid, act, rwbs);
1105 }
1106
1107 static int blk_log_action(struct trace_iterator *iter, const char *act)
1108 {
1109 char rwbs[6];
1110 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1111
1112 fill_rwbs(rwbs, t);
1113 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1114 MAJOR(t->device), MINOR(t->device), act, rwbs);
1115 }
1116
1117 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1118 {
1119 const unsigned char *pdu_buf;
1120 int pdu_len;
1121 int i, end, ret;
1122
1123 pdu_buf = pdu_start(ent);
1124 pdu_len = te_blk_io_trace(ent)->pdu_len;
1125
1126 if (!pdu_len)
1127 return 1;
1128
1129 /* find the last zero that needs to be printed */
1130 for (end = pdu_len - 1; end >= 0; end--)
1131 if (pdu_buf[end])
1132 break;
1133 end++;
1134
1135 if (!trace_seq_putc(s, '('))
1136 return 0;
1137
1138 for (i = 0; i < pdu_len; i++) {
1139
1140 ret = trace_seq_printf(s, "%s%02x",
1141 i == 0 ? "" : " ", pdu_buf[i]);
1142 if (!ret)
1143 return ret;
1144
1145 /*
1146 * stop when the rest is just zeroes and indicate so
1147 * with a ".." appended
1148 */
1149 if (i == end && end != pdu_len - 1)
1150 return trace_seq_puts(s, " ..) ");
1151 }
1152
1153 return trace_seq_puts(s, ") ");
1154 }
1155
1156 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1157 {
1158 char cmd[TASK_COMM_LEN];
1159
1160 trace_find_cmdline(ent->pid, cmd);
1161
1162 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1163 int ret;
1164
1165 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1166 if (!ret)
1167 return 0;
1168 ret = blk_log_dump_pdu(s, ent);
1169 if (!ret)
1170 return 0;
1171 return trace_seq_printf(s, "[%s]\n", cmd);
1172 } else {
1173 if (t_sec(ent))
1174 return trace_seq_printf(s, "%llu + %u [%s]\n",
1175 t_sector(ent), t_sec(ent), cmd);
1176 return trace_seq_printf(s, "[%s]\n", cmd);
1177 }
1178 }
1179
1180 static int blk_log_with_error(struct trace_seq *s,
1181 const struct trace_entry *ent)
1182 {
1183 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1184 int ret;
1185
1186 ret = blk_log_dump_pdu(s, ent);
1187 if (ret)
1188 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1189 return 0;
1190 } else {
1191 if (t_sec(ent))
1192 return trace_seq_printf(s, "%llu + %u [%d]\n",
1193 t_sector(ent),
1194 t_sec(ent), t_error(ent));
1195 return trace_seq_printf(s, "%llu [%d]\n",
1196 t_sector(ent), t_error(ent));
1197 }
1198 }
1199
1200 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1201 {
1202 struct blk_io_trace_remap r = { .device_from = 0, };
1203
1204 get_pdu_remap(ent, &r);
1205 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1206 t_sector(ent), t_sec(ent),
1207 MAJOR(r.device_from), MINOR(r.device_from),
1208 (unsigned long long)r.sector_from);
1209 }
1210
1211 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1212 {
1213 char cmd[TASK_COMM_LEN];
1214
1215 trace_find_cmdline(ent->pid, cmd);
1216
1217 return trace_seq_printf(s, "[%s]\n", cmd);
1218 }
1219
1220 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1221 {
1222 char cmd[TASK_COMM_LEN];
1223
1224 trace_find_cmdline(ent->pid, cmd);
1225
1226 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1227 }
1228
1229 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1230 {
1231 char cmd[TASK_COMM_LEN];
1232
1233 trace_find_cmdline(ent->pid, cmd);
1234
1235 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1236 get_pdu_int(ent), cmd);
1237 }
1238
1239 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1240 {
1241 int ret;
1242 const struct blk_io_trace *t = te_blk_io_trace(ent);
1243
1244 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1245 if (ret)
1246 return trace_seq_putc(s, '\n');
1247 return ret;
1248 }
1249
1250 /*
1251 * struct tracer operations
1252 */
1253
1254 static void blk_tracer_print_header(struct seq_file *m)
1255 {
1256 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1257 return;
1258 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1259 "# | | | | | |\n");
1260 }
1261
1262 static void blk_tracer_start(struct trace_array *tr)
1263 {
1264 blk_tracer_enabled = true;
1265 }
1266
1267 static int blk_tracer_init(struct trace_array *tr)
1268 {
1269 blk_tr = tr;
1270 blk_tracer_start(tr);
1271 return 0;
1272 }
1273
1274 static void blk_tracer_stop(struct trace_array *tr)
1275 {
1276 blk_tracer_enabled = false;
1277 }
1278
1279 static void blk_tracer_reset(struct trace_array *tr)
1280 {
1281 blk_tracer_stop(tr);
1282 }
1283
1284 static const struct {
1285 const char *act[2];
1286 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1287 } what2act[] = {
1288 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1289 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1290 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1291 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1292 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1293 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1294 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1295 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1296 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1297 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1298 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1299 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1300 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1301 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1302 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1303 };
1304
1305 static enum print_line_t print_one_line(struct trace_iterator *iter,
1306 bool classic)
1307 {
1308 struct trace_seq *s = &iter->seq;
1309 const struct blk_io_trace *t;
1310 u16 what;
1311 int ret;
1312 bool long_act;
1313 blk_log_action_t *log_action;
1314
1315 t = te_blk_io_trace(iter->ent);
1316 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1317 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1318 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1319
1320 if (t->action == BLK_TN_MESSAGE) {
1321 ret = log_action(iter, long_act ? "message" : "m");
1322 if (ret)
1323 ret = blk_log_msg(s, iter->ent);
1324 goto out;
1325 }
1326
1327 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1328 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1329 else {
1330 ret = log_action(iter, what2act[what].act[long_act]);
1331 if (ret)
1332 ret = what2act[what].print(s, iter->ent);
1333 }
1334 out:
1335 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1336 }
1337
1338 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1339 int flags, struct trace_event *event)
1340 {
1341 return print_one_line(iter, false);
1342 }
1343
1344 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1345 {
1346 struct trace_seq *s = &iter->seq;
1347 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1348 const int offset = offsetof(struct blk_io_trace, sector);
1349 struct blk_io_trace old = {
1350 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1351 .time = iter->ts,
1352 };
1353
1354 if (!trace_seq_putmem(s, &old, offset))
1355 return 0;
1356 return trace_seq_putmem(s, &t->sector,
1357 sizeof(old) - offset + t->pdu_len);
1358 }
1359
1360 static enum print_line_t
1361 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1362 struct trace_event *event)
1363 {
1364 return blk_trace_synthesize_old_trace(iter) ?
1365 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1366 }
1367
1368 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1369 {
1370 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1371 return TRACE_TYPE_UNHANDLED;
1372
1373 return print_one_line(iter, true);
1374 }
1375
1376 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1377 {
1378 /* don't output context-info for blk_classic output */
1379 if (bit == TRACE_BLK_OPT_CLASSIC) {
1380 if (set)
1381 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1382 else
1383 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1384 }
1385 return 0;
1386 }
1387
1388 static struct tracer blk_tracer __read_mostly = {
1389 .name = "blk",
1390 .init = blk_tracer_init,
1391 .reset = blk_tracer_reset,
1392 .start = blk_tracer_start,
1393 .stop = blk_tracer_stop,
1394 .print_header = blk_tracer_print_header,
1395 .print_line = blk_tracer_print_line,
1396 .flags = &blk_tracer_flags,
1397 .set_flag = blk_tracer_set_flag,
1398 };
1399
1400 static struct trace_event_functions trace_blk_event_funcs = {
1401 .trace = blk_trace_event_print,
1402 .binary = blk_trace_event_print_binary,
1403 };
1404
1405 static struct trace_event trace_blk_event = {
1406 .type = TRACE_BLK,
1407 .funcs = &trace_blk_event_funcs,
1408 };
1409
1410 static int __init init_blk_tracer(void)
1411 {
1412 if (!register_ftrace_event(&trace_blk_event)) {
1413 pr_warning("Warning: could not register block events\n");
1414 return 1;
1415 }
1416
1417 if (register_tracer(&blk_tracer) != 0) {
1418 pr_warning("Warning: could not register the block tracer\n");
1419 unregister_ftrace_event(&trace_blk_event);
1420 return 1;
1421 }
1422
1423 return 0;
1424 }
1425
1426 device_initcall(init_blk_tracer);
1427
1428 static int blk_trace_remove_queue(struct request_queue *q)
1429 {
1430 struct blk_trace *bt;
1431
1432 bt = xchg(&q->blk_trace, NULL);
1433 if (bt == NULL)
1434 return -EINVAL;
1435
1436 if (atomic_dec_and_test(&blk_probes_ref))
1437 blk_unregister_tracepoints();
1438
1439 blk_trace_free(bt);
1440 return 0;
1441 }
1442
1443 /*
1444 * Setup everything required to start tracing
1445 */
1446 static int blk_trace_setup_queue(struct request_queue *q,
1447 struct block_device *bdev)
1448 {
1449 struct blk_trace *old_bt, *bt = NULL;
1450 int ret = -ENOMEM;
1451
1452 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1453 if (!bt)
1454 return -ENOMEM;
1455
1456 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1457 if (!bt->msg_data)
1458 goto free_bt;
1459
1460 bt->dev = bdev->bd_dev;
1461 bt->act_mask = (u16)-1;
1462
1463 blk_trace_setup_lba(bt, bdev);
1464
1465 old_bt = xchg(&q->blk_trace, bt);
1466 if (old_bt != NULL) {
1467 (void)xchg(&q->blk_trace, old_bt);
1468 ret = -EBUSY;
1469 goto free_bt;
1470 }
1471
1472 if (atomic_inc_return(&blk_probes_ref) == 1)
1473 blk_register_tracepoints();
1474 return 0;
1475
1476 free_bt:
1477 blk_trace_free(bt);
1478 return ret;
1479 }
1480
1481 /*
1482 * sysfs interface to enable and configure tracing
1483 */
1484
1485 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1486 struct device_attribute *attr,
1487 char *buf);
1488 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1489 struct device_attribute *attr,
1490 const char *buf, size_t count);
1491 #define BLK_TRACE_DEVICE_ATTR(_name) \
1492 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1493 sysfs_blk_trace_attr_show, \
1494 sysfs_blk_trace_attr_store)
1495
1496 static BLK_TRACE_DEVICE_ATTR(enable);
1497 static BLK_TRACE_DEVICE_ATTR(act_mask);
1498 static BLK_TRACE_DEVICE_ATTR(pid);
1499 static BLK_TRACE_DEVICE_ATTR(start_lba);
1500 static BLK_TRACE_DEVICE_ATTR(end_lba);
1501
1502 static struct attribute *blk_trace_attrs[] = {
1503 &dev_attr_enable.attr,
1504 &dev_attr_act_mask.attr,
1505 &dev_attr_pid.attr,
1506 &dev_attr_start_lba.attr,
1507 &dev_attr_end_lba.attr,
1508 NULL
1509 };
1510
1511 struct attribute_group blk_trace_attr_group = {
1512 .name = "trace",
1513 .attrs = blk_trace_attrs,
1514 };
1515
1516 static const struct {
1517 int mask;
1518 const char *str;
1519 } mask_maps[] = {
1520 { BLK_TC_READ, "read" },
1521 { BLK_TC_WRITE, "write" },
1522 { BLK_TC_BARRIER, "barrier" },
1523 { BLK_TC_SYNC, "sync" },
1524 { BLK_TC_QUEUE, "queue" },
1525 { BLK_TC_REQUEUE, "requeue" },
1526 { BLK_TC_ISSUE, "issue" },
1527 { BLK_TC_COMPLETE, "complete" },
1528 { BLK_TC_FS, "fs" },
1529 { BLK_TC_PC, "pc" },
1530 { BLK_TC_AHEAD, "ahead" },
1531 { BLK_TC_META, "meta" },
1532 { BLK_TC_DISCARD, "discard" },
1533 { BLK_TC_DRV_DATA, "drv_data" },
1534 };
1535
1536 static int blk_trace_str2mask(const char *str)
1537 {
1538 int i;
1539 int mask = 0;
1540 char *buf, *s, *token;
1541
1542 buf = kstrdup(str, GFP_KERNEL);
1543 if (buf == NULL)
1544 return -ENOMEM;
1545 s = strstrip(buf);
1546
1547 while (1) {
1548 token = strsep(&s, ",");
1549 if (token == NULL)
1550 break;
1551
1552 if (*token == '\0')
1553 continue;
1554
1555 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1556 if (strcasecmp(token, mask_maps[i].str) == 0) {
1557 mask |= mask_maps[i].mask;
1558 break;
1559 }
1560 }
1561 if (i == ARRAY_SIZE(mask_maps)) {
1562 mask = -EINVAL;
1563 break;
1564 }
1565 }
1566 kfree(buf);
1567
1568 return mask;
1569 }
1570
1571 static ssize_t blk_trace_mask2str(char *buf, int mask)
1572 {
1573 int i;
1574 char *p = buf;
1575
1576 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1577 if (mask & mask_maps[i].mask) {
1578 p += sprintf(p, "%s%s",
1579 (p == buf) ? "" : ",", mask_maps[i].str);
1580 }
1581 }
1582 *p++ = '\n';
1583
1584 return p - buf;
1585 }
1586
1587 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1588 {
1589 if (bdev->bd_disk == NULL)
1590 return NULL;
1591
1592 return bdev_get_queue(bdev);
1593 }
1594
1595 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1596 struct device_attribute *attr,
1597 char *buf)
1598 {
1599 struct hd_struct *p = dev_to_part(dev);
1600 struct request_queue *q;
1601 struct block_device *bdev;
1602 ssize_t ret = -ENXIO;
1603
1604 lock_kernel();
1605 bdev = bdget(part_devt(p));
1606 if (bdev == NULL)
1607 goto out_unlock_kernel;
1608
1609 q = blk_trace_get_queue(bdev);
1610 if (q == NULL)
1611 goto out_bdput;
1612
1613 mutex_lock(&bdev->bd_mutex);
1614
1615 if (attr == &dev_attr_enable) {
1616 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1617 goto out_unlock_bdev;
1618 }
1619
1620 if (q->blk_trace == NULL)
1621 ret = sprintf(buf, "disabled\n");
1622 else if (attr == &dev_attr_act_mask)
1623 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1624 else if (attr == &dev_attr_pid)
1625 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1626 else if (attr == &dev_attr_start_lba)
1627 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1628 else if (attr == &dev_attr_end_lba)
1629 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1630
1631 out_unlock_bdev:
1632 mutex_unlock(&bdev->bd_mutex);
1633 out_bdput:
1634 bdput(bdev);
1635 out_unlock_kernel:
1636 unlock_kernel();
1637 return ret;
1638 }
1639
1640 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1641 struct device_attribute *attr,
1642 const char *buf, size_t count)
1643 {
1644 struct block_device *bdev;
1645 struct request_queue *q;
1646 struct hd_struct *p;
1647 u64 value;
1648 ssize_t ret = -EINVAL;
1649
1650 if (count == 0)
1651 goto out;
1652
1653 if (attr == &dev_attr_act_mask) {
1654 if (sscanf(buf, "%llx", &value) != 1) {
1655 /* Assume it is a list of trace category names */
1656 ret = blk_trace_str2mask(buf);
1657 if (ret < 0)
1658 goto out;
1659 value = ret;
1660 }
1661 } else if (sscanf(buf, "%llu", &value) != 1)
1662 goto out;
1663
1664 ret = -ENXIO;
1665
1666 lock_kernel();
1667 p = dev_to_part(dev);
1668 bdev = bdget(part_devt(p));
1669 if (bdev == NULL)
1670 goto out_unlock_kernel;
1671
1672 q = blk_trace_get_queue(bdev);
1673 if (q == NULL)
1674 goto out_bdput;
1675
1676 mutex_lock(&bdev->bd_mutex);
1677
1678 if (attr == &dev_attr_enable) {
1679 if (value)
1680 ret = blk_trace_setup_queue(q, bdev);
1681 else
1682 ret = blk_trace_remove_queue(q);
1683 goto out_unlock_bdev;
1684 }
1685
1686 ret = 0;
1687 if (q->blk_trace == NULL)
1688 ret = blk_trace_setup_queue(q, bdev);
1689
1690 if (ret == 0) {
1691 if (attr == &dev_attr_act_mask)
1692 q->blk_trace->act_mask = value;
1693 else if (attr == &dev_attr_pid)
1694 q->blk_trace->pid = value;
1695 else if (attr == &dev_attr_start_lba)
1696 q->blk_trace->start_lba = value;
1697 else if (attr == &dev_attr_end_lba)
1698 q->blk_trace->end_lba = value;
1699 }
1700
1701 out_unlock_bdev:
1702 mutex_unlock(&bdev->bd_mutex);
1703 out_bdput:
1704 bdput(bdev);
1705 out_unlock_kernel:
1706 unlock_kernel();
1707 out:
1708 return ret ? ret : count;
1709 }
1710
1711 int blk_trace_init_sysfs(struct device *dev)
1712 {
1713 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1714 }
1715
1716 void blk_trace_remove_sysfs(struct device *dev)
1717 {
1718 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1719 }
1720
1721 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1722
1723 #ifdef CONFIG_EVENT_TRACING
1724
1725 void blk_dump_cmd(char *buf, struct request *rq)
1726 {
1727 int i, end;
1728 int len = rq->cmd_len;
1729 unsigned char *cmd = rq->cmd;
1730
1731 if (!blk_pc_request(rq)) {
1732 buf[0] = '\0';
1733 return;
1734 }
1735
1736 for (end = len - 1; end >= 0; end--)
1737 if (cmd[end])
1738 break;
1739 end++;
1740
1741 for (i = 0; i < len; i++) {
1742 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1743 if (i == end && end != len - 1) {
1744 sprintf(buf, " ..");
1745 break;
1746 }
1747 }
1748 }
1749
1750 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1751 {
1752 int i = 0;
1753
1754 if (rw & WRITE)
1755 rwbs[i++] = 'W';
1756 else if (rw & 1 << BIO_RW_DISCARD)
1757 rwbs[i++] = 'D';
1758 else if (bytes)
1759 rwbs[i++] = 'R';
1760 else
1761 rwbs[i++] = 'N';
1762
1763 if (rw & 1 << BIO_RW_AHEAD)
1764 rwbs[i++] = 'A';
1765 if (rw & 1 << BIO_RW_BARRIER)
1766 rwbs[i++] = 'B';
1767 if (rw & 1 << BIO_RW_SYNCIO)
1768 rwbs[i++] = 'S';
1769 if (rw & 1 << BIO_RW_META)
1770 rwbs[i++] = 'M';
1771
1772 rwbs[i] = '\0';
1773 }
1774
1775 void blk_fill_rwbs_rq(char *rwbs, struct request *rq)
1776 {
1777 int rw = rq->cmd_flags & 0x03;
1778 int bytes;
1779
1780 if (blk_discard_rq(rq))
1781 rw |= (1 << BIO_RW_DISCARD);
1782
1783 bytes = blk_rq_bytes(rq);
1784
1785 blk_fill_rwbs(rwbs, rw, bytes);
1786 }
1787
1788 #endif /* CONFIG_EVENT_TRACING */
1789
Linux kernel - Deliverables
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