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eCryptfs: Copy lower directory inode times and size on link
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / trace / blktrace.c
blob07f945a99430bfe58fd1dde80365a7e6e663147d
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/debugfs.h>
25 #include <linux/smp_lock.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
35 static unsigned int blktrace_seq __read_mostly = 1;
36
37 static struct trace_array *blk_tr;
38 static 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
43 static struct tracer_opt blk_tracer_opts[] = {
44 /* Default disable the minimalistic output */
45 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
46 { }
47 };
48
49 static struct tracer_flags blk_tracer_flags = {
50 .val = 0,
51 .opts = blk_tracer_opts,
52 };
53
54 /* Global reference count of probes */
55 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
56
57 static void blk_register_tracepoints(void);
58 static void blk_unregister_tracepoints(void);
59
60 /*
61 * Send out a notify message.
62 */
63 static 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());
92 record_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 */
109 static 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
115 static 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
130 void __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 local_irq_save(flags);
142 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
143 va_start(args, fmt);
144 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
145 va_end(args);
146
147 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
148 local_irq_restore(flags);
149 }
150 EXPORT_SYMBOL_GPL(__trace_note_message);
151
152 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
153 pid_t pid)
154 {
155 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
156 return 1;
157 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
158 return 1;
159 if (bt->pid && pid != bt->pid)
160 return 1;
161
162 return 0;
163 }
164
165 /*
166 * Data direction bit lookup
167 */
168 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
169 BLK_TC_ACT(BLK_TC_WRITE) };
170
171 /* The ilog2() calls fall out because they're constant */
172 #define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
173 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name))
174
175 /*
176 * The worker for the various blk_add_trace*() types. Fills out a
177 * blk_io_trace structure and places it in a per-cpu subbuffer.
178 */
179 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
180 int rw, u32 what, int error, int pdu_len, void *pdu_data)
181 {
182 struct task_struct *tsk = current;
183 struct ring_buffer_event *event = NULL;
184 struct ring_buffer *buffer = NULL;
185 struct blk_io_trace *t;
186 unsigned long flags = 0;
187 unsigned long *sequence;
188 pid_t pid;
189 int cpu, pc = 0;
190 bool blk_tracer = blk_tracer_enabled;
191
192 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
193 return;
194
195 what |= ddir_act[rw & WRITE];
196 what |= MASK_TC_BIT(rw, BARRIER);
197 what |= MASK_TC_BIT(rw, SYNCIO);
198 what |= MASK_TC_BIT(rw, AHEAD);
199 what |= MASK_TC_BIT(rw, META);
200 what |= MASK_TC_BIT(rw, DISCARD);
201
202 pid = tsk->pid;
203 if (act_log_check(bt, what, sector, pid))
204 return;
205 cpu = raw_smp_processor_id();
206
207 if (blk_tracer) {
208 tracing_record_cmdline(current);
209
210 buffer = blk_tr->buffer;
211 pc = preempt_count();
212 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
213 sizeof(*t) + pdu_len,
214 0, pc);
215 if (!event)
216 return;
217 t = ring_buffer_event_data(event);
218 goto record_it;
219 }
220
221 /*
222 * A word about the locking here - we disable interrupts to reserve
223 * some space in the relay per-cpu buffer, to prevent an irq
224 * from coming in and stepping on our toes.
225 */
226 local_irq_save(flags);
227
228 if (unlikely(tsk->btrace_seq != blktrace_seq))
229 trace_note_tsk(bt, tsk);
230
231 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
232 if (t) {
233 sequence = per_cpu_ptr(bt->sequence, cpu);
234
235 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
236 t->sequence = ++(*sequence);
237 t->time = ktime_to_ns(ktime_get());
238 record_it:
239 /*
240 * These two are not needed in ftrace as they are in the
241 * generic trace_entry, filled by tracing_generic_entry_update,
242 * but for the trace_event->bin() synthesizer benefit we do it
243 * here too.
244 */
245 t->cpu = cpu;
246 t->pid = pid;
247
248 t->sector = sector;
249 t->bytes = bytes;
250 t->action = what;
251 t->device = bt->dev;
252 t->error = error;
253 t->pdu_len = pdu_len;
254
255 if (pdu_len)
256 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
257
258 if (blk_tracer) {
259 trace_buffer_unlock_commit(buffer, event, 0, pc);
260 return;
261 }
262 }
263
264 local_irq_restore(flags);
265 }
266
267 static struct dentry *blk_tree_root;
268 static DEFINE_MUTEX(blk_tree_mutex);
269
270 static void blk_trace_free(struct blk_trace *bt)
271 {
272 debugfs_remove(bt->msg_file);
273 debugfs_remove(bt->dropped_file);
274 relay_close(bt->rchan);
275 debugfs_remove(bt->dir);
276 free_percpu(bt->sequence);
277 free_percpu(bt->msg_data);
278 kfree(bt);
279 }
280
281 static void blk_trace_cleanup(struct blk_trace *bt)
282 {
283 blk_trace_free(bt);
284 if (atomic_dec_and_test(&blk_probes_ref))
285 blk_unregister_tracepoints();
286 }
287
288 int blk_trace_remove(struct request_queue *q)
289 {
290 struct blk_trace *bt;
291
292 bt = xchg(&q->blk_trace, NULL);
293 if (!bt)
294 return -EINVAL;
295
296 if (bt->trace_state != Blktrace_running)
297 blk_trace_cleanup(bt);
298
299 return 0;
300 }
301 EXPORT_SYMBOL_GPL(blk_trace_remove);
302
303 static int blk_dropped_open(struct inode *inode, struct file *filp)
304 {
305 filp->private_data = inode->i_private;
306
307 return 0;
308 }
309
310 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
311 size_t count, loff_t *ppos)
312 {
313 struct blk_trace *bt = filp->private_data;
314 char buf[16];
315
316 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
317
318 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
319 }
320
321 static const struct file_operations blk_dropped_fops = {
322 .owner = THIS_MODULE,
323 .open = blk_dropped_open,
324 .read = blk_dropped_read,
325 };
326
327 static int blk_msg_open(struct inode *inode, struct file *filp)
328 {
329 filp->private_data = inode->i_private;
330
331 return 0;
332 }
333
334 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
335 size_t count, loff_t *ppos)
336 {
337 char *msg;
338 struct blk_trace *bt;
339
340 if (count >= BLK_TN_MAX_MSG)
341 return -EINVAL;
342
343 msg = kmalloc(count + 1, GFP_KERNEL);
344 if (msg == NULL)
345 return -ENOMEM;
346
347 if (copy_from_user(msg, buffer, count)) {
348 kfree(msg);
349 return -EFAULT;
350 }
351
352 msg[count] = '\0';
353 bt = filp->private_data;
354 __trace_note_message(bt, "%s", msg);
355 kfree(msg);
356
357 return count;
358 }
359
360 static const struct file_operations blk_msg_fops = {
361 .owner = THIS_MODULE,
362 .open = blk_msg_open,
363 .write = blk_msg_write,
364 };
365
366 /*
367 * Keep track of how many times we encountered a full subbuffer, to aid
368 * the user space app in telling how many lost events there were.
369 */
370 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
371 void *prev_subbuf, size_t prev_padding)
372 {
373 struct blk_trace *bt;
374
375 if (!relay_buf_full(buf))
376 return 1;
377
378 bt = buf->chan->private_data;
379 atomic_inc(&bt->dropped);
380 return 0;
381 }
382
383 static int blk_remove_buf_file_callback(struct dentry *dentry)
384 {
385 debugfs_remove(dentry);
386
387 return 0;
388 }
389
390 static struct dentry *blk_create_buf_file_callback(const char *filename,
391 struct dentry *parent,
392 int mode,
393 struct rchan_buf *buf,
394 int *is_global)
395 {
396 return debugfs_create_file(filename, mode, parent, buf,
397 &relay_file_operations);
398 }
399
400 static struct rchan_callbacks blk_relay_callbacks = {
401 .subbuf_start = blk_subbuf_start_callback,
402 .create_buf_file = blk_create_buf_file_callback,
403 .remove_buf_file = blk_remove_buf_file_callback,
404 };
405
406 static void blk_trace_setup_lba(struct blk_trace *bt,
407 struct block_device *bdev)
408 {
409 struct hd_struct *part = NULL;
410
411 if (bdev)
412 part = bdev->bd_part;
413
414 if (part) {
415 bt->start_lba = part->start_sect;
416 bt->end_lba = part->start_sect + part->nr_sects;
417 } else {
418 bt->start_lba = 0;
419 bt->end_lba = -1ULL;
420 }
421 }
422
423 /*
424 * Setup everything required to start tracing
425 */
426 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
427 struct block_device *bdev,
428 struct blk_user_trace_setup *buts)
429 {
430 struct blk_trace *old_bt, *bt = NULL;
431 struct dentry *dir = NULL;
432 int ret, i;
433
434 if (!buts->buf_size || !buts->buf_nr)
435 return -EINVAL;
436
437 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
438 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
439
440 /*
441 * some device names have larger paths - convert the slashes
442 * to underscores for this to work as expected
443 */
444 for (i = 0; i < strlen(buts->name); i++)
445 if (buts->name[i] == '/')
446 buts->name[i] = '_';
447
448 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
449 if (!bt)
450 return -ENOMEM;
451
452 ret = -ENOMEM;
453 bt->sequence = alloc_percpu(unsigned long);
454 if (!bt->sequence)
455 goto err;
456
457 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
458 if (!bt->msg_data)
459 goto err;
460
461 ret = -ENOENT;
462
463 mutex_lock(&blk_tree_mutex);
464 if (!blk_tree_root) {
465 blk_tree_root = debugfs_create_dir("block", NULL);
466 if (!blk_tree_root) {
467 mutex_unlock(&blk_tree_mutex);
468 goto err;
469 }
470 }
471 mutex_unlock(&blk_tree_mutex);
472
473 dir = debugfs_create_dir(buts->name, blk_tree_root);
474
475 if (!dir)
476 goto err;
477
478 bt->dir = dir;
479 bt->dev = dev;
480 atomic_set(&bt->dropped, 0);
481
482 ret = -EIO;
483 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
484 &blk_dropped_fops);
485 if (!bt->dropped_file)
486 goto err;
487
488 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
489 if (!bt->msg_file)
490 goto err;
491
492 bt->rchan = relay_open("trace", dir, buts->buf_size,
493 buts->buf_nr, &blk_relay_callbacks, bt);
494 if (!bt->rchan)
495 goto err;
496
497 bt->act_mask = buts->act_mask;
498 if (!bt->act_mask)
499 bt->act_mask = (u16) -1;
500
501 blk_trace_setup_lba(bt, bdev);
502
503 /* overwrite with user settings */
504 if (buts->start_lba)
505 bt->start_lba = buts->start_lba;
506 if (buts->end_lba)
507 bt->end_lba = buts->end_lba;
508
509 bt->pid = buts->pid;
510 bt->trace_state = Blktrace_setup;
511
512 ret = -EBUSY;
513 old_bt = xchg(&q->blk_trace, bt);
514 if (old_bt) {
515 (void) xchg(&q->blk_trace, old_bt);
516 goto err;
517 }
518
519 if (atomic_inc_return(&blk_probes_ref) == 1)
520 blk_register_tracepoints();
521
522 return 0;
523 err:
524 blk_trace_free(bt);
525 return ret;
526 }
527
528 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
529 struct block_device *bdev,
530 char __user *arg)
531 {
532 struct blk_user_trace_setup buts;
533 int ret;
534
535 ret = copy_from_user(&buts, arg, sizeof(buts));
536 if (ret)
537 return -EFAULT;
538
539 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
540 if (ret)
541 return ret;
542
543 if (copy_to_user(arg, &buts, sizeof(buts))) {
544 blk_trace_remove(q);
545 return -EFAULT;
546 }
547 return 0;
548 }
549 EXPORT_SYMBOL_GPL(blk_trace_setup);
550
551 int blk_trace_startstop(struct request_queue *q, int start)
552 {
553 int ret;
554 struct blk_trace *bt = q->blk_trace;
555
556 if (bt == NULL)
557 return -EINVAL;
558
559 /*
560 * For starting a trace, we can transition from a setup or stopped
561 * trace. For stopping a trace, the state must be running
562 */
563 ret = -EINVAL;
564 if (start) {
565 if (bt->trace_state == Blktrace_setup ||
566 bt->trace_state == Blktrace_stopped) {
567 blktrace_seq++;
568 smp_mb();
569 bt->trace_state = Blktrace_running;
570
571 trace_note_time(bt);
572 ret = 0;
573 }
574 } else {
575 if (bt->trace_state == Blktrace_running) {
576 bt->trace_state = Blktrace_stopped;
577 relay_flush(bt->rchan);
578 ret = 0;
579 }
580 }
581
582 return ret;
583 }
584 EXPORT_SYMBOL_GPL(blk_trace_startstop);
585
586 /**
587 * blk_trace_ioctl: - handle the ioctls associated with tracing
588 * @bdev: the block device
589 * @cmd: the ioctl cmd
590 * @arg: the argument data, if any
591 *
592 **/
593 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
594 {
595 struct request_queue *q;
596 int ret, start = 0;
597 char b[BDEVNAME_SIZE];
598
599 q = bdev_get_queue(bdev);
600 if (!q)
601 return -ENXIO;
602
603 mutex_lock(&bdev->bd_mutex);
604
605 switch (cmd) {
606 case BLKTRACESETUP:
607 bdevname(bdev, b);
608 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
609 break;
610 case BLKTRACESTART:
611 start = 1;
612 case BLKTRACESTOP:
613 ret = blk_trace_startstop(q, start);
614 break;
615 case BLKTRACETEARDOWN:
616 ret = blk_trace_remove(q);
617 break;
618 default:
619 ret = -ENOTTY;
620 break;
621 }
622
623 mutex_unlock(&bdev->bd_mutex);
624 return ret;
625 }
626
627 /**
628 * blk_trace_shutdown: - stop and cleanup trace structures
629 * @q: the request queue associated with the device
630 *
631 **/
632 void blk_trace_shutdown(struct request_queue *q)
633 {
634 if (q->blk_trace) {
635 blk_trace_startstop(q, 0);
636 blk_trace_remove(q);
637 }
638 }
639
640 /*
641 * blktrace probes
642 */
643
644 /**
645 * blk_add_trace_rq - Add a trace for a request oriented action
646 * @q: queue the io is for
647 * @rq: the source request
648 * @what: the action
649 *
650 * Description:
651 * Records an action against a request. Will log the bio offset + size.
652 *
653 **/
654 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
655 u32 what)
656 {
657 struct blk_trace *bt = q->blk_trace;
658 int rw = rq->cmd_flags & 0x03;
659
660 if (likely(!bt))
661 return;
662
663 if (blk_discard_rq(rq))
664 rw |= (1 << BIO_RW_DISCARD);
665
666 if (blk_pc_request(rq)) {
667 what |= BLK_TC_ACT(BLK_TC_PC);
668 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
669 what, rq->errors, rq->cmd_len, rq->cmd);
670 } else {
671 what |= BLK_TC_ACT(BLK_TC_FS);
672 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
673 what, rq->errors, 0, NULL);
674 }
675 }
676
677 static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq)
678 {
679 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
680 }
681
682 static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq)
683 {
684 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
685 }
686
687 static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq)
688 {
689 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
690 }
691
692 static void blk_add_trace_rq_requeue(struct request_queue *q,
693 struct request *rq)
694 {
695 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
696 }
697
698 static void blk_add_trace_rq_complete(struct request_queue *q,
699 struct request *rq)
700 {
701 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
702 }
703
704 /**
705 * blk_add_trace_bio - Add a trace for a bio oriented action
706 * @q: queue the io is for
707 * @bio: the source bio
708 * @what: the action
709 *
710 * Description:
711 * Records an action against a bio. Will log the bio offset + size.
712 *
713 **/
714 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
715 u32 what)
716 {
717 struct blk_trace *bt = q->blk_trace;
718
719 if (likely(!bt))
720 return;
721
722 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
723 !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
724 }
725
726 static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio)
727 {
728 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
729 }
730
731 static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio)
732 {
733 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
734 }
735
736 static void blk_add_trace_bio_backmerge(struct request_queue *q,
737 struct bio *bio)
738 {
739 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
740 }
741
742 static void blk_add_trace_bio_frontmerge(struct request_queue *q,
743 struct bio *bio)
744 {
745 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
746 }
747
748 static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio)
749 {
750 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
751 }
752
753 static void blk_add_trace_getrq(struct request_queue *q,
754 struct bio *bio, int rw)
755 {
756 if (bio)
757 blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
758 else {
759 struct blk_trace *bt = q->blk_trace;
760
761 if (bt)
762 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
763 }
764 }
765
766
767 static void blk_add_trace_sleeprq(struct request_queue *q,
768 struct bio *bio, int rw)
769 {
770 if (bio)
771 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
772 else {
773 struct blk_trace *bt = q->blk_trace;
774
775 if (bt)
776 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
777 0, 0, NULL);
778 }
779 }
780
781 static void blk_add_trace_plug(struct request_queue *q)
782 {
783 struct blk_trace *bt = q->blk_trace;
784
785 if (bt)
786 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
787 }
788
789 static void blk_add_trace_unplug_io(struct request_queue *q)
790 {
791 struct blk_trace *bt = q->blk_trace;
792
793 if (bt) {
794 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
795 __be64 rpdu = cpu_to_be64(pdu);
796
797 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
798 sizeof(rpdu), &rpdu);
799 }
800 }
801
802 static void blk_add_trace_unplug_timer(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_TIMER, 0,
811 sizeof(rpdu), &rpdu);
812 }
813 }
814
815 static void blk_add_trace_split(struct request_queue *q, struct bio *bio,
816 unsigned int pdu)
817 {
818 struct blk_trace *bt = q->blk_trace;
819
820 if (bt) {
821 __be64 rpdu = cpu_to_be64(pdu);
822
823 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
824 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
825 sizeof(rpdu), &rpdu);
826 }
827 }
828
829 /**
830 * blk_add_trace_remap - Add a trace for a remap operation
831 * @q: queue the io is for
832 * @bio: the source bio
833 * @dev: target device
834 * @from: source sector
835 *
836 * Description:
837 * Device mapper or raid target sometimes need to split a bio because
838 * it spans a stripe (or similar). Add a trace for that action.
839 *
840 **/
841 static void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
842 dev_t dev, sector_t from)
843 {
844 struct blk_trace *bt = q->blk_trace;
845 struct blk_io_trace_remap r;
846
847 if (likely(!bt))
848 return;
849
850 r.device_from = cpu_to_be32(dev);
851 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
852 r.sector_from = cpu_to_be64(from);
853
854 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
855 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
856 sizeof(r), &r);
857 }
858
859 /**
860 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
861 * @q: queue the io is for
862 * @rq: the source request
863 * @dev: target device
864 * @from: source sector
865 *
866 * Description:
867 * Device mapper remaps request to other devices.
868 * Add a trace for that action.
869 *
870 **/
871 static void blk_add_trace_rq_remap(struct request_queue *q,
872 struct request *rq, dev_t dev,
873 sector_t from)
874 {
875 struct blk_trace *bt = q->blk_trace;
876 struct blk_io_trace_remap r;
877
878 if (likely(!bt))
879 return;
880
881 r.device_from = cpu_to_be32(dev);
882 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
883 r.sector_from = cpu_to_be64(from);
884
885 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
886 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
887 sizeof(r), &r);
888 }
889
890 /**
891 * blk_add_driver_data - Add binary message with driver-specific data
892 * @q: queue the io is for
893 * @rq: io request
894 * @data: driver-specific data
895 * @len: length of driver-specific data
896 *
897 * Description:
898 * Some drivers might want to write driver-specific data per request.
899 *
900 **/
901 void blk_add_driver_data(struct request_queue *q,
902 struct request *rq,
903 void *data, size_t len)
904 {
905 struct blk_trace *bt = q->blk_trace;
906
907 if (likely(!bt))
908 return;
909
910 if (blk_pc_request(rq))
911 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
912 BLK_TA_DRV_DATA, rq->errors, len, data);
913 else
914 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
915 BLK_TA_DRV_DATA, rq->errors, len, data);
916 }
917 EXPORT_SYMBOL_GPL(blk_add_driver_data);
918
919 static void blk_register_tracepoints(void)
920 {
921 int ret;
922
923 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort);
924 WARN_ON(ret);
925 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert);
926 WARN_ON(ret);
927 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue);
928 WARN_ON(ret);
929 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue);
930 WARN_ON(ret);
931 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete);
932 WARN_ON(ret);
933 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce);
934 WARN_ON(ret);
935 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete);
936 WARN_ON(ret);
937 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
938 WARN_ON(ret);
939 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
940 WARN_ON(ret);
941 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue);
942 WARN_ON(ret);
943 ret = register_trace_block_getrq(blk_add_trace_getrq);
944 WARN_ON(ret);
945 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq);
946 WARN_ON(ret);
947 ret = register_trace_block_plug(blk_add_trace_plug);
948 WARN_ON(ret);
949 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer);
950 WARN_ON(ret);
951 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io);
952 WARN_ON(ret);
953 ret = register_trace_block_split(blk_add_trace_split);
954 WARN_ON(ret);
955 ret = register_trace_block_remap(blk_add_trace_remap);
956 WARN_ON(ret);
957 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap);
958 WARN_ON(ret);
959 }
960
961 static void blk_unregister_tracepoints(void)
962 {
963 unregister_trace_block_rq_remap(blk_add_trace_rq_remap);
964 unregister_trace_block_remap(blk_add_trace_remap);
965 unregister_trace_block_split(blk_add_trace_split);
966 unregister_trace_block_unplug_io(blk_add_trace_unplug_io);
967 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer);
968 unregister_trace_block_plug(blk_add_trace_plug);
969 unregister_trace_block_sleeprq(blk_add_trace_sleeprq);
970 unregister_trace_block_getrq(blk_add_trace_getrq);
971 unregister_trace_block_bio_queue(blk_add_trace_bio_queue);
972 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
973 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
974 unregister_trace_block_bio_complete(blk_add_trace_bio_complete);
975 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce);
976 unregister_trace_block_rq_complete(blk_add_trace_rq_complete);
977 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue);
978 unregister_trace_block_rq_issue(blk_add_trace_rq_issue);
979 unregister_trace_block_rq_insert(blk_add_trace_rq_insert);
980 unregister_trace_block_rq_abort(blk_add_trace_rq_abort);
981
982 tracepoint_synchronize_unregister();
983 }
984
985 /*
986 * struct blk_io_tracer formatting routines
987 */
988
989 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
990 {
991 int i = 0;
992 int tc = t->action >> BLK_TC_SHIFT;
993
994 if (t->action == BLK_TN_MESSAGE) {
995 rwbs[i++] = 'N';
996 goto out;
997 }
998
999 if (tc & BLK_TC_DISCARD)
1000 rwbs[i++] = 'D';
1001 else if (tc & BLK_TC_WRITE)
1002 rwbs[i++] = 'W';
1003 else if (t->bytes)
1004 rwbs[i++] = 'R';
1005 else
1006 rwbs[i++] = 'N';
1007
1008 if (tc & BLK_TC_AHEAD)
1009 rwbs[i++] = 'A';
1010 if (tc & BLK_TC_BARRIER)
1011 rwbs[i++] = 'B';
1012 if (tc & BLK_TC_SYNC)
1013 rwbs[i++] = 'S';
1014 if (tc & BLK_TC_META)
1015 rwbs[i++] = 'M';
1016 out:
1017 rwbs[i] = '\0';
1018 }
1019
1020 static inline
1021 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1022 {
1023 return (const struct blk_io_trace *)ent;
1024 }
1025
1026 static inline const void *pdu_start(const struct trace_entry *ent)
1027 {
1028 return te_blk_io_trace(ent) + 1;
1029 }
1030
1031 static inline u32 t_action(const struct trace_entry *ent)
1032 {
1033 return te_blk_io_trace(ent)->action;
1034 }
1035
1036 static inline u32 t_bytes(const struct trace_entry *ent)
1037 {
1038 return te_blk_io_trace(ent)->bytes;
1039 }
1040
1041 static inline u32 t_sec(const struct trace_entry *ent)
1042 {
1043 return te_blk_io_trace(ent)->bytes >> 9;
1044 }
1045
1046 static inline unsigned long long t_sector(const struct trace_entry *ent)
1047 {
1048 return te_blk_io_trace(ent)->sector;
1049 }
1050
1051 static inline __u16 t_error(const struct trace_entry *ent)
1052 {
1053 return te_blk_io_trace(ent)->error;
1054 }
1055
1056 static __u64 get_pdu_int(const struct trace_entry *ent)
1057 {
1058 const __u64 *val = pdu_start(ent);
1059 return be64_to_cpu(*val);
1060 }
1061
1062 static void get_pdu_remap(const struct trace_entry *ent,
1063 struct blk_io_trace_remap *r)
1064 {
1065 const struct blk_io_trace_remap *__r = pdu_start(ent);
1066 __u64 sector_from = __r->sector_from;
1067
1068 r->device_from = be32_to_cpu(__r->device_from);
1069 r->device_to = be32_to_cpu(__r->device_to);
1070 r->sector_from = be64_to_cpu(sector_from);
1071 }
1072
1073 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1074
1075 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1076 {
1077 char rwbs[6];
1078 unsigned long long ts = iter->ts;
1079 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1080 unsigned secs = (unsigned long)ts;
1081 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1082
1083 fill_rwbs(rwbs, t);
1084
1085 return trace_seq_printf(&iter->seq,
1086 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1087 MAJOR(t->device), MINOR(t->device), iter->cpu,
1088 secs, nsec_rem, iter->ent->pid, act, rwbs);
1089 }
1090
1091 static int blk_log_action(struct trace_iterator *iter, const char *act)
1092 {
1093 char rwbs[6];
1094 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1095
1096 fill_rwbs(rwbs, t);
1097 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1098 MAJOR(t->device), MINOR(t->device), act, rwbs);
1099 }
1100
1101 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1102 {
1103 const unsigned char *pdu_buf;
1104 int pdu_len;
1105 int i, end, ret;
1106
1107 pdu_buf = pdu_start(ent);
1108 pdu_len = te_blk_io_trace(ent)->pdu_len;
1109
1110 if (!pdu_len)
1111 return 1;
1112
1113 /* find the last zero that needs to be printed */
1114 for (end = pdu_len - 1; end >= 0; end--)
1115 if (pdu_buf[end])
1116 break;
1117 end++;
1118
1119 if (!trace_seq_putc(s, '('))
1120 return 0;
1121
1122 for (i = 0; i < pdu_len; i++) {
1123
1124 ret = trace_seq_printf(s, "%s%02x",
1125 i == 0 ? "" : " ", pdu_buf[i]);
1126 if (!ret)
1127 return ret;
1128
1129 /*
1130 * stop when the rest is just zeroes and indicate so
1131 * with a ".." appended
1132 */
1133 if (i == end && end != pdu_len - 1)
1134 return trace_seq_puts(s, " ..) ");
1135 }
1136
1137 return trace_seq_puts(s, ") ");
1138 }
1139
1140 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1141 {
1142 char cmd[TASK_COMM_LEN];
1143
1144 trace_find_cmdline(ent->pid, cmd);
1145
1146 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1147 int ret;
1148
1149 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1150 if (!ret)
1151 return 0;
1152 ret = blk_log_dump_pdu(s, ent);
1153 if (!ret)
1154 return 0;
1155 return trace_seq_printf(s, "[%s]\n", cmd);
1156 } else {
1157 if (t_sec(ent))
1158 return trace_seq_printf(s, "%llu + %u [%s]\n",
1159 t_sector(ent), t_sec(ent), cmd);
1160 return trace_seq_printf(s, "[%s]\n", cmd);
1161 }
1162 }
1163
1164 static int blk_log_with_error(struct trace_seq *s,
1165 const struct trace_entry *ent)
1166 {
1167 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1168 int ret;
1169
1170 ret = blk_log_dump_pdu(s, ent);
1171 if (ret)
1172 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1173 return 0;
1174 } else {
1175 if (t_sec(ent))
1176 return trace_seq_printf(s, "%llu + %u [%d]\n",
1177 t_sector(ent),
1178 t_sec(ent), t_error(ent));
1179 return trace_seq_printf(s, "%llu [%d]\n",
1180 t_sector(ent), t_error(ent));
1181 }
1182 }
1183
1184 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1185 {
1186 struct blk_io_trace_remap r = { .device_from = 0, };
1187
1188 get_pdu_remap(ent, &r);
1189 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1190 t_sector(ent), t_sec(ent),
1191 MAJOR(r.device_from), MINOR(r.device_from),
1192 (unsigned long long)r.sector_from);
1193 }
1194
1195 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1196 {
1197 char cmd[TASK_COMM_LEN];
1198
1199 trace_find_cmdline(ent->pid, cmd);
1200
1201 return trace_seq_printf(s, "[%s]\n", cmd);
1202 }
1203
1204 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1205 {
1206 char cmd[TASK_COMM_LEN];
1207
1208 trace_find_cmdline(ent->pid, cmd);
1209
1210 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1211 }
1212
1213 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1214 {
1215 char cmd[TASK_COMM_LEN];
1216
1217 trace_find_cmdline(ent->pid, cmd);
1218
1219 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1220 get_pdu_int(ent), cmd);
1221 }
1222
1223 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1224 {
1225 int ret;
1226 const struct blk_io_trace *t = te_blk_io_trace(ent);
1227
1228 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1229 if (ret)
1230 return trace_seq_putc(s, '\n');
1231 return ret;
1232 }
1233
1234 /*
1235 * struct tracer operations
1236 */
1237
1238 static void blk_tracer_print_header(struct seq_file *m)
1239 {
1240 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1241 return;
1242 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1243 "# | | | | | |\n");
1244 }
1245
1246 static void blk_tracer_start(struct trace_array *tr)
1247 {
1248 blk_tracer_enabled = true;
1249 }
1250
1251 static int blk_tracer_init(struct trace_array *tr)
1252 {
1253 blk_tr = tr;
1254 blk_tracer_start(tr);
1255 return 0;
1256 }
1257
1258 static void blk_tracer_stop(struct trace_array *tr)
1259 {
1260 blk_tracer_enabled = false;
1261 }
1262
1263 static void blk_tracer_reset(struct trace_array *tr)
1264 {
1265 blk_tracer_stop(tr);
1266 }
1267
1268 static const struct {
1269 const char *act[2];
1270 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1271 } what2act[] = {
1272 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1273 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1274 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1275 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1276 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1277 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1278 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1279 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1280 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1281 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1282 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1283 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1284 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1285 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1286 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1287 };
1288
1289 static enum print_line_t print_one_line(struct trace_iterator *iter,
1290 bool classic)
1291 {
1292 struct trace_seq *s = &iter->seq;
1293 const struct blk_io_trace *t;
1294 u16 what;
1295 int ret;
1296 bool long_act;
1297 blk_log_action_t *log_action;
1298
1299 t = te_blk_io_trace(iter->ent);
1300 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1301 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1302 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1303
1304 if (t->action == BLK_TN_MESSAGE) {
1305 ret = log_action(iter, long_act ? "message" : "m");
1306 if (ret)
1307 ret = blk_log_msg(s, iter->ent);
1308 goto out;
1309 }
1310
1311 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1312 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1313 else {
1314 ret = log_action(iter, what2act[what].act[long_act]);
1315 if (ret)
1316 ret = what2act[what].print(s, iter->ent);
1317 }
1318 out:
1319 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1320 }
1321
1322 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1323 int flags)
1324 {
1325 return print_one_line(iter, false);
1326 }
1327
1328 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1329 {
1330 struct trace_seq *s = &iter->seq;
1331 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1332 const int offset = offsetof(struct blk_io_trace, sector);
1333 struct blk_io_trace old = {
1334 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1335 .time = iter->ts,
1336 };
1337
1338 if (!trace_seq_putmem(s, &old, offset))
1339 return 0;
1340 return trace_seq_putmem(s, &t->sector,
1341 sizeof(old) - offset + t->pdu_len);
1342 }
1343
1344 static enum print_line_t
1345 blk_trace_event_print_binary(struct trace_iterator *iter, int flags)
1346 {
1347 return blk_trace_synthesize_old_trace(iter) ?
1348 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1349 }
1350
1351 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1352 {
1353 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1354 return TRACE_TYPE_UNHANDLED;
1355
1356 return print_one_line(iter, true);
1357 }
1358
1359 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1360 {
1361 /* don't output context-info for blk_classic output */
1362 if (bit == TRACE_BLK_OPT_CLASSIC) {
1363 if (set)
1364 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1365 else
1366 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1367 }
1368 return 0;
1369 }
1370
1371 static struct tracer blk_tracer __read_mostly = {
1372 .name = "blk",
1373 .init = blk_tracer_init,
1374 .reset = blk_tracer_reset,
1375 .start = blk_tracer_start,
1376 .stop = blk_tracer_stop,
1377 .print_header = blk_tracer_print_header,
1378 .print_line = blk_tracer_print_line,
1379 .flags = &blk_tracer_flags,
1380 .set_flag = blk_tracer_set_flag,
1381 };
1382
1383 static struct trace_event trace_blk_event = {
1384 .type = TRACE_BLK,
1385 .trace = blk_trace_event_print,
1386 .binary = blk_trace_event_print_binary,
1387 };
1388
1389 static int __init init_blk_tracer(void)
1390 {
1391 if (!register_ftrace_event(&trace_blk_event)) {
1392 pr_warning("Warning: could not register block events\n");
1393 return 1;
1394 }
1395
1396 if (register_tracer(&blk_tracer) != 0) {
1397 pr_warning("Warning: could not register the block tracer\n");
1398 unregister_ftrace_event(&trace_blk_event);
1399 return 1;
1400 }
1401
1402 return 0;
1403 }
1404
1405 device_initcall(init_blk_tracer);
1406
1407 static int blk_trace_remove_queue(struct request_queue *q)
1408 {
1409 struct blk_trace *bt;
1410
1411 bt = xchg(&q->blk_trace, NULL);
1412 if (bt == NULL)
1413 return -EINVAL;
1414
1415 if (atomic_dec_and_test(&blk_probes_ref))
1416 blk_unregister_tracepoints();
1417
1418 blk_trace_free(bt);
1419 return 0;
1420 }
1421
1422 /*
1423 * Setup everything required to start tracing
1424 */
1425 static int blk_trace_setup_queue(struct request_queue *q,
1426 struct block_device *bdev)
1427 {
1428 struct blk_trace *old_bt, *bt = NULL;
1429 int ret = -ENOMEM;
1430
1431 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1432 if (!bt)
1433 return -ENOMEM;
1434
1435 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1436 if (!bt->msg_data)
1437 goto free_bt;
1438
1439 bt->dev = bdev->bd_dev;
1440 bt->act_mask = (u16)-1;
1441
1442 blk_trace_setup_lba(bt, bdev);
1443
1444 old_bt = xchg(&q->blk_trace, bt);
1445 if (old_bt != NULL) {
1446 (void)xchg(&q->blk_trace, old_bt);
1447 ret = -EBUSY;
1448 goto free_bt;
1449 }
1450
1451 if (atomic_inc_return(&blk_probes_ref) == 1)
1452 blk_register_tracepoints();
1453 return 0;
1454
1455 free_bt:
1456 blk_trace_free(bt);
1457 return ret;
1458 }
1459
1460 /*
1461 * sysfs interface to enable and configure tracing
1462 */
1463
1464 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1465 struct device_attribute *attr,
1466 char *buf);
1467 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1468 struct device_attribute *attr,
1469 const char *buf, size_t count);
1470 #define BLK_TRACE_DEVICE_ATTR(_name) \
1471 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1472 sysfs_blk_trace_attr_show, \
1473 sysfs_blk_trace_attr_store)
1474
1475 static BLK_TRACE_DEVICE_ATTR(enable);
1476 static BLK_TRACE_DEVICE_ATTR(act_mask);
1477 static BLK_TRACE_DEVICE_ATTR(pid);
1478 static BLK_TRACE_DEVICE_ATTR(start_lba);
1479 static BLK_TRACE_DEVICE_ATTR(end_lba);
1480
1481 static struct attribute *blk_trace_attrs[] = {
1482 &dev_attr_enable.attr,
1483 &dev_attr_act_mask.attr,
1484 &dev_attr_pid.attr,
1485 &dev_attr_start_lba.attr,
1486 &dev_attr_end_lba.attr,
1487 NULL
1488 };
1489
1490 struct attribute_group blk_trace_attr_group = {
1491 .name = "trace",
1492 .attrs = blk_trace_attrs,
1493 };
1494
1495 static const struct {
1496 int mask;
1497 const char *str;
1498 } mask_maps[] = {
1499 { BLK_TC_READ, "read" },
1500 { BLK_TC_WRITE, "write" },
1501 { BLK_TC_BARRIER, "barrier" },
1502 { BLK_TC_SYNC, "sync" },
1503 { BLK_TC_QUEUE, "queue" },
1504 { BLK_TC_REQUEUE, "requeue" },
1505 { BLK_TC_ISSUE, "issue" },
1506 { BLK_TC_COMPLETE, "complete" },
1507 { BLK_TC_FS, "fs" },
1508 { BLK_TC_PC, "pc" },
1509 { BLK_TC_AHEAD, "ahead" },
1510 { BLK_TC_META, "meta" },
1511 { BLK_TC_DISCARD, "discard" },
1512 { BLK_TC_DRV_DATA, "drv_data" },
1513 };
1514
1515 static int blk_trace_str2mask(const char *str)
1516 {
1517 int i;
1518 int mask = 0;
1519 char *buf, *s, *token;
1520
1521 buf = kstrdup(str, GFP_KERNEL);
1522 if (buf == NULL)
1523 return -ENOMEM;
1524 s = strstrip(buf);
1525
1526 while (1) {
1527 token = strsep(&s, ",");
1528 if (token == NULL)
1529 break;
1530
1531 if (*token == '\0')
1532 continue;
1533
1534 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1535 if (strcasecmp(token, mask_maps[i].str) == 0) {
1536 mask |= mask_maps[i].mask;
1537 break;
1538 }
1539 }
1540 if (i == ARRAY_SIZE(mask_maps)) {
1541 mask = -EINVAL;
1542 break;
1543 }
1544 }
1545 kfree(buf);
1546
1547 return mask;
1548 }
1549
1550 static ssize_t blk_trace_mask2str(char *buf, int mask)
1551 {
1552 int i;
1553 char *p = buf;
1554
1555 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1556 if (mask & mask_maps[i].mask) {
1557 p += sprintf(p, "%s%s",
1558 (p == buf) ? "" : ",", mask_maps[i].str);
1559 }
1560 }
1561 *p++ = '\n';
1562
1563 return p - buf;
1564 }
1565
1566 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1567 {
1568 if (bdev->bd_disk == NULL)
1569 return NULL;
1570
1571 return bdev_get_queue(bdev);
1572 }
1573
1574 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1575 struct device_attribute *attr,
1576 char *buf)
1577 {
1578 struct hd_struct *p = dev_to_part(dev);
1579 struct request_queue *q;
1580 struct block_device *bdev;
1581 ssize_t ret = -ENXIO;
1582
1583 lock_kernel();
1584 bdev = bdget(part_devt(p));
1585 if (bdev == NULL)
1586 goto out_unlock_kernel;
1587
1588 q = blk_trace_get_queue(bdev);
1589 if (q == NULL)
1590 goto out_bdput;
1591
1592 mutex_lock(&bdev->bd_mutex);
1593
1594 if (attr == &dev_attr_enable) {
1595 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1596 goto out_unlock_bdev;
1597 }
1598
1599 if (q->blk_trace == NULL)
1600 ret = sprintf(buf, "disabled\n");
1601 else if (attr == &dev_attr_act_mask)
1602 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1603 else if (attr == &dev_attr_pid)
1604 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1605 else if (attr == &dev_attr_start_lba)
1606 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1607 else if (attr == &dev_attr_end_lba)
1608 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1609
1610 out_unlock_bdev:
1611 mutex_unlock(&bdev->bd_mutex);
1612 out_bdput:
1613 bdput(bdev);
1614 out_unlock_kernel:
1615 unlock_kernel();
1616 return ret;
1617 }
1618
1619 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1620 struct device_attribute *attr,
1621 const char *buf, size_t count)
1622 {
1623 struct block_device *bdev;
1624 struct request_queue *q;
1625 struct hd_struct *p;
1626 u64 value;
1627 ssize_t ret = -EINVAL;
1628
1629 if (count == 0)
1630 goto out;
1631
1632 if (attr == &dev_attr_act_mask) {
1633 if (sscanf(buf, "%llx", &value) != 1) {
1634 /* Assume it is a list of trace category names */
1635 ret = blk_trace_str2mask(buf);
1636 if (ret < 0)
1637 goto out;
1638 value = ret;
1639 }
1640 } else if (sscanf(buf, "%llu", &value) != 1)
1641 goto out;
1642
1643 ret = -ENXIO;
1644
1645 lock_kernel();
1646 p = dev_to_part(dev);
1647 bdev = bdget(part_devt(p));
1648 if (bdev == NULL)
1649 goto out_unlock_kernel;
1650
1651 q = blk_trace_get_queue(bdev);
1652 if (q == NULL)
1653 goto out_bdput;
1654
1655 mutex_lock(&bdev->bd_mutex);
1656
1657 if (attr == &dev_attr_enable) {
1658 if (value)
1659 ret = blk_trace_setup_queue(q, bdev);
1660 else
1661 ret = blk_trace_remove_queue(q);
1662 goto out_unlock_bdev;
1663 }
1664
1665 ret = 0;
1666 if (q->blk_trace == NULL)
1667 ret = blk_trace_setup_queue(q, bdev);
1668
1669 if (ret == 0) {
1670 if (attr == &dev_attr_act_mask)
1671 q->blk_trace->act_mask = value;
1672 else if (attr == &dev_attr_pid)
1673 q->blk_trace->pid = value;
1674 else if (attr == &dev_attr_start_lba)
1675 q->blk_trace->start_lba = value;
1676 else if (attr == &dev_attr_end_lba)
1677 q->blk_trace->end_lba = value;
1678 }
1679
1680 out_unlock_bdev:
1681 mutex_unlock(&bdev->bd_mutex);
1682 out_bdput:
1683 bdput(bdev);
1684 out_unlock_kernel:
1685 unlock_kernel();
1686 out:
1687 return ret ? ret : count;
1688 }
1689
1690 int blk_trace_init_sysfs(struct device *dev)
1691 {
1692 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1693 }
1694
1695 void blk_trace_remove_sysfs(struct device *dev)
1696 {
1697 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1698 }
1699
1700 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1701
1702 #ifdef CONFIG_EVENT_TRACING
1703
1704 void blk_dump_cmd(char *buf, struct request *rq)
1705 {
1706 int i, end;
1707 int len = rq->cmd_len;
1708 unsigned char *cmd = rq->cmd;
1709
1710 if (!blk_pc_request(rq)) {
1711 buf[0] = '\0';
1712 return;
1713 }
1714
1715 for (end = len - 1; end >= 0; end--)
1716 if (cmd[end])
1717 break;
1718 end++;
1719
1720 for (i = 0; i < len; i++) {
1721 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1722 if (i == end && end != len - 1) {
1723 sprintf(buf, " ..");
1724 break;
1725 }
1726 }
1727 }
1728
1729 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1730 {
1731 int i = 0;
1732
1733 if (rw & WRITE)
1734 rwbs[i++] = 'W';
1735 else if (rw & 1 << BIO_RW_DISCARD)
1736 rwbs[i++] = 'D';
1737 else if (bytes)
1738 rwbs[i++] = 'R';
1739 else
1740 rwbs[i++] = 'N';
1741
1742 if (rw & 1 << BIO_RW_AHEAD)
1743 rwbs[i++] = 'A';
1744 if (rw & 1 << BIO_RW_BARRIER)
1745 rwbs[i++] = 'B';
1746 if (rw & 1 << BIO_RW_SYNCIO)
1747 rwbs[i++] = 'S';
1748 if (rw & 1 << BIO_RW_META)
1749 rwbs[i++] = 'M';
1750
1751 rwbs[i] = '\0';
1752 }
1753
1754 void blk_fill_rwbs_rq(char *rwbs, struct request *rq)
1755 {
1756 int rw = rq->cmd_flags & 0x03;
1757 int bytes;
1758
1759 if (blk_discard_rq(rq))
1760 rw |= (1 << BIO_RW_DISCARD);
1761
1762 bytes = blk_rq_bytes(rq);
1763
1764 blk_fill_rwbs(rwbs, rw, bytes);
1765 }
1766
1767 #endif /* CONFIG_EVENT_TRACING */
1768
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