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