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sh: Use DECLARE_EXPORT() for mcount symbol export.
[linux-2.6/btrfs-unstable.git] / kernel / trace / blktrace.c
blob39af8af6fc302c981226ab8c8f277026b319ca4a
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 <linux/uaccess.h>
27
28 #include <trace/events/block.h>
29
30 #include "trace_output.h"
31
32 #ifdef CONFIG_BLK_DEV_IO_TRACE
33
34 static unsigned int blktrace_seq __read_mostly = 1;
35
36 static struct trace_array *blk_tr;
37 static bool blk_tracer_enabled __read_mostly;
38
39 /* Select an alternative, minimalistic output than the original one */
40 #define TRACE_BLK_OPT_CLASSIC 0x1
41
42 static struct tracer_opt blk_tracer_opts[] = {
43 /* Default disable the minimalistic output */
44 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
45 { }
46 };
47
48 static struct tracer_flags blk_tracer_flags = {
49 .val = 0,
50 .opts = blk_tracer_opts,
51 };
52
53 /* Global reference count of probes */
54 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
55
56 static void blk_register_tracepoints(void);
57 static void blk_unregister_tracepoints(void);
58
59 /*
60 * Send out a notify message.
61 */
62 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
63 const void *data, size_t len)
64 {
65 struct blk_io_trace *t;
66 struct ring_buffer_event *event = NULL;
67 int pc = 0;
68 int cpu = smp_processor_id();
69 bool blk_tracer = blk_tracer_enabled;
70
71 if (blk_tracer) {
72 pc = preempt_count();
73 event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
74 sizeof(*t) + len,
75 0, pc);
76 if (!event)
77 return;
78 t = ring_buffer_event_data(event);
79 goto record_it;
80 }
81
82 if (!bt->rchan)
83 return;
84
85 t = relay_reserve(bt->rchan, sizeof(*t) + len);
86 if (t) {
87 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
88 t->time = ktime_to_ns(ktime_get());
89 record_it:
90 t->device = bt->dev;
91 t->action = action;
92 t->pid = pid;
93 t->cpu = cpu;
94 t->pdu_len = len;
95 memcpy((void *) t + sizeof(*t), data, len);
96
97 if (blk_tracer)
98 trace_buffer_unlock_commit(blk_tr, event, 0, pc);
99 }
100 }
101
102 /*
103 * Send out a notify for this process, if we haven't done so since a trace
104 * started
105 */
106 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
107 {
108 tsk->btrace_seq = blktrace_seq;
109 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
110 }
111
112 static void trace_note_time(struct blk_trace *bt)
113 {
114 struct timespec now;
115 unsigned long flags;
116 u32 words[2];
117
118 getnstimeofday(&now);
119 words[0] = now.tv_sec;
120 words[1] = now.tv_nsec;
121
122 local_irq_save(flags);
123 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
124 local_irq_restore(flags);
125 }
126
127 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
128 {
129 int n;
130 va_list args;
131 unsigned long flags;
132 char *buf;
133
134 if (unlikely(bt->trace_state != Blktrace_running &&
135 !blk_tracer_enabled))
136 return;
137
138 local_irq_save(flags);
139 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
140 va_start(args, fmt);
141 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
142 va_end(args);
143
144 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
145 local_irq_restore(flags);
146 }
147 EXPORT_SYMBOL_GPL(__trace_note_message);
148
149 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
150 pid_t pid)
151 {
152 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
153 return 1;
154 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
155 return 1;
156 if (bt->pid && pid != bt->pid)
157 return 1;
158
159 return 0;
160 }
161
162 /*
163 * Data direction bit lookup
164 */
165 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
166 BLK_TC_ACT(BLK_TC_WRITE) };
167
168 /* The ilog2() calls fall out because they're constant */
169 #define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
170 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name))
171
172 /*
173 * The worker for the various blk_add_trace*() types. Fills out a
174 * blk_io_trace structure and places it in a per-cpu subbuffer.
175 */
176 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
177 int rw, u32 what, int error, int pdu_len, void *pdu_data)
178 {
179 struct task_struct *tsk = current;
180 struct ring_buffer_event *event = NULL;
181 struct blk_io_trace *t;
182 unsigned long flags = 0;
183 unsigned long *sequence;
184 pid_t pid;
185 int cpu, pc = 0;
186 bool blk_tracer = blk_tracer_enabled;
187
188 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
189 return;
190
191 what |= ddir_act[rw & WRITE];
192 what |= MASK_TC_BIT(rw, BARRIER);
193 what |= MASK_TC_BIT(rw, SYNCIO);
194 what |= MASK_TC_BIT(rw, AHEAD);
195 what |= MASK_TC_BIT(rw, META);
196 what |= MASK_TC_BIT(rw, DISCARD);
197
198 pid = tsk->pid;
199 if (act_log_check(bt, what, sector, pid))
200 return;
201 cpu = raw_smp_processor_id();
202
203 if (blk_tracer) {
204 tracing_record_cmdline(current);
205
206 pc = preempt_count();
207 event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
208 sizeof(*t) + pdu_len,
209 0, pc);
210 if (!event)
211 return;
212 t = ring_buffer_event_data(event);
213 goto record_it;
214 }
215
216 /*
217 * A word about the locking here - we disable interrupts to reserve
218 * some space in the relay per-cpu buffer, to prevent an irq
219 * from coming in and stepping on our toes.
220 */
221 local_irq_save(flags);
222
223 if (unlikely(tsk->btrace_seq != blktrace_seq))
224 trace_note_tsk(bt, tsk);
225
226 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
227 if (t) {
228 sequence = per_cpu_ptr(bt->sequence, cpu);
229
230 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
231 t->sequence = ++(*sequence);
232 t->time = ktime_to_ns(ktime_get());
233 record_it:
234 /*
235 * These two are not needed in ftrace as they are in the
236 * generic trace_entry, filled by tracing_generic_entry_update,
237 * but for the trace_event->bin() synthesizer benefit we do it
238 * here too.
239 */
240 t->cpu = cpu;
241 t->pid = pid;
242
243 t->sector = sector;
244 t->bytes = bytes;
245 t->action = what;
246 t->device = bt->dev;
247 t->error = error;
248 t->pdu_len = pdu_len;
249
250 if (pdu_len)
251 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
252
253 if (blk_tracer) {
254 trace_buffer_unlock_commit(blk_tr, event, 0, pc);
255 return;
256 }
257 }
258
259 local_irq_restore(flags);
260 }
261
262 static struct dentry *blk_tree_root;
263 static DEFINE_MUTEX(blk_tree_mutex);
264
265 static void blk_trace_free(struct blk_trace *bt)
266 {
267 debugfs_remove(bt->msg_file);
268 debugfs_remove(bt->dropped_file);
269 debugfs_remove(bt->dir);
270 relay_close(bt->rchan);
271 free_percpu(bt->sequence);
272 free_percpu(bt->msg_data);
273 kfree(bt);
274 }
275
276 static void blk_trace_cleanup(struct blk_trace *bt)
277 {
278 blk_trace_free(bt);
279 if (atomic_dec_and_test(&blk_probes_ref))
280 blk_unregister_tracepoints();
281 }
282
283 int blk_trace_remove(struct request_queue *q)
284 {
285 struct blk_trace *bt;
286
287 bt = xchg(&q->blk_trace, NULL);
288 if (!bt)
289 return -EINVAL;
290
291 if (bt->trace_state != Blktrace_running)
292 blk_trace_cleanup(bt);
293
294 return 0;
295 }
296 EXPORT_SYMBOL_GPL(blk_trace_remove);
297
298 static int blk_dropped_open(struct inode *inode, struct file *filp)
299 {
300 filp->private_data = inode->i_private;
301
302 return 0;
303 }
304
305 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
306 size_t count, loff_t *ppos)
307 {
308 struct blk_trace *bt = filp->private_data;
309 char buf[16];
310
311 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
312
313 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
314 }
315
316 static const struct file_operations blk_dropped_fops = {
317 .owner = THIS_MODULE,
318 .open = blk_dropped_open,
319 .read = blk_dropped_read,
320 };
321
322 static int blk_msg_open(struct inode *inode, struct file *filp)
323 {
324 filp->private_data = inode->i_private;
325
326 return 0;
327 }
328
329 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
330 size_t count, loff_t *ppos)
331 {
332 char *msg;
333 struct blk_trace *bt;
334
335 if (count >= BLK_TN_MAX_MSG)
336 return -EINVAL;
337
338 msg = kmalloc(count + 1, GFP_KERNEL);
339 if (msg == NULL)
340 return -ENOMEM;
341
342 if (copy_from_user(msg, buffer, count)) {
343 kfree(msg);
344 return -EFAULT;
345 }
346
347 msg[count] = '\0';
348 bt = filp->private_data;
349 __trace_note_message(bt, "%s", msg);
350 kfree(msg);
351
352 return count;
353 }
354
355 static const struct file_operations blk_msg_fops = {
356 .owner = THIS_MODULE,
357 .open = blk_msg_open,
358 .write = blk_msg_write,
359 };
360
361 /*
362 * Keep track of how many times we encountered a full subbuffer, to aid
363 * the user space app in telling how many lost events there were.
364 */
365 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
366 void *prev_subbuf, size_t prev_padding)
367 {
368 struct blk_trace *bt;
369
370 if (!relay_buf_full(buf))
371 return 1;
372
373 bt = buf->chan->private_data;
374 atomic_inc(&bt->dropped);
375 return 0;
376 }
377
378 static int blk_remove_buf_file_callback(struct dentry *dentry)
379 {
380 struct dentry *parent = dentry->d_parent;
381 debugfs_remove(dentry);
382
383 /*
384 * this will fail for all but the last file, but that is ok. what we
385 * care about is the top level buts->name directory going away, when
386 * the last trace file is gone. Then we don't have to rmdir() that
387 * manually on trace stop, so it nicely solves the issue with
388 * force killing of running traces.
389 */
390
391 debugfs_remove(parent);
392 return 0;
393 }
394
395 static struct dentry *blk_create_buf_file_callback(const char *filename,
396 struct dentry *parent,
397 int mode,
398 struct rchan_buf *buf,
399 int *is_global)
400 {
401 return debugfs_create_file(filename, mode, parent, buf,
402 &relay_file_operations);
403 }
404
405 static struct rchan_callbacks blk_relay_callbacks = {
406 .subbuf_start = blk_subbuf_start_callback,
407 .create_buf_file = blk_create_buf_file_callback,
408 .remove_buf_file = blk_remove_buf_file_callback,
409 };
410
411 static void blk_trace_setup_lba(struct blk_trace *bt,
412 struct block_device *bdev)
413 {
414 struct hd_struct *part = NULL;
415
416 if (bdev)
417 part = bdev->bd_part;
418
419 if (part) {
420 bt->start_lba = part->start_sect;
421 bt->end_lba = part->start_sect + part->nr_sects;
422 } else {
423 bt->start_lba = 0;
424 bt->end_lba = -1ULL;
425 }
426 }
427
428 /*
429 * Setup everything required to start tracing
430 */
431 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
432 struct block_device *bdev,
433 struct blk_user_trace_setup *buts)
434 {
435 struct blk_trace *old_bt, *bt = NULL;
436 struct dentry *dir = NULL;
437 int ret, i;
438
439 if (!buts->buf_size || !buts->buf_nr)
440 return -EINVAL;
441
442 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
443 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
444
445 /*
446 * some device names have larger paths - convert the slashes
447 * to underscores for this to work as expected
448 */
449 for (i = 0; i < strlen(buts->name); i++)
450 if (buts->name[i] == '/')
451 buts->name[i] = '_';
452
453 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
454 if (!bt)
455 return -ENOMEM;
456
457 ret = -ENOMEM;
458 bt->sequence = alloc_percpu(unsigned long);
459 if (!bt->sequence)
460 goto err;
461
462 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
463 if (!bt->msg_data)
464 goto err;
465
466 ret = -ENOENT;
467
468 mutex_lock(&blk_tree_mutex);
469 if (!blk_tree_root) {
470 blk_tree_root = debugfs_create_dir("block", NULL);
471 if (!blk_tree_root) {
472 mutex_unlock(&blk_tree_mutex);
473 goto err;
474 }
475 }
476 mutex_unlock(&blk_tree_mutex);
477
478 dir = debugfs_create_dir(buts->name, blk_tree_root);
479
480 if (!dir)
481 goto err;
482
483 bt->dir = dir;
484 bt->dev = dev;
485 atomic_set(&bt->dropped, 0);
486
487 ret = -EIO;
488 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
489 &blk_dropped_fops);
490 if (!bt->dropped_file)
491 goto err;
492
493 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
494 if (!bt->msg_file)
495 goto err;
496
497 bt->rchan = relay_open("trace", dir, buts->buf_size,
498 buts->buf_nr, &blk_relay_callbacks, bt);
499 if (!bt->rchan)
500 goto err;
501
502 bt->act_mask = buts->act_mask;
503 if (!bt->act_mask)
504 bt->act_mask = (u16) -1;
505
506 blk_trace_setup_lba(bt, bdev);
507
508 /* overwrite with user settings */
509 if (buts->start_lba)
510 bt->start_lba = buts->start_lba;
511 if (buts->end_lba)
512 bt->end_lba = buts->end_lba;
513
514 bt->pid = buts->pid;
515 bt->trace_state = Blktrace_setup;
516
517 ret = -EBUSY;
518 old_bt = xchg(&q->blk_trace, bt);
519 if (old_bt) {
520 (void) xchg(&q->blk_trace, old_bt);
521 goto err;
522 }
523
524 if (atomic_inc_return(&blk_probes_ref) == 1)
525 blk_register_tracepoints();
526
527 return 0;
528 err:
529 blk_trace_free(bt);
530 return ret;
531 }
532
533 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
534 struct block_device *bdev,
535 char __user *arg)
536 {
537 struct blk_user_trace_setup buts;
538 int ret;
539
540 ret = copy_from_user(&buts, arg, sizeof(buts));
541 if (ret)
542 return -EFAULT;
543
544 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
545 if (ret)
546 return ret;
547
548 if (copy_to_user(arg, &buts, sizeof(buts)))
549 return -EFAULT;
550
551 return 0;
552 }
553 EXPORT_SYMBOL_GPL(blk_trace_setup);
554
555 int blk_trace_startstop(struct request_queue *q, int start)
556 {
557 int ret;
558 struct blk_trace *bt = q->blk_trace;
559
560 if (bt == NULL)
561 return -EINVAL;
562
563 /*
564 * For starting a trace, we can transition from a setup or stopped
565 * trace. For stopping a trace, the state must be running
566 */
567 ret = -EINVAL;
568 if (start) {
569 if (bt->trace_state == Blktrace_setup ||
570 bt->trace_state == Blktrace_stopped) {
571 blktrace_seq++;
572 smp_mb();
573 bt->trace_state = Blktrace_running;
574
575 trace_note_time(bt);
576 ret = 0;
577 }
578 } else {
579 if (bt->trace_state == Blktrace_running) {
580 bt->trace_state = Blktrace_stopped;
581 relay_flush(bt->rchan);
582 ret = 0;
583 }
584 }
585
586 return ret;
587 }
588 EXPORT_SYMBOL_GPL(blk_trace_startstop);
589
590 /**
591 * blk_trace_ioctl: - handle the ioctls associated with tracing
592 * @bdev: the block device
593 * @cmd: the ioctl cmd
594 * @arg: the argument data, if any
595 *
596 **/
597 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
598 {
599 struct request_queue *q;
600 int ret, start = 0;
601 char b[BDEVNAME_SIZE];
602
603 q = bdev_get_queue(bdev);
604 if (!q)
605 return -ENXIO;
606
607 mutex_lock(&bdev->bd_mutex);
608
609 switch (cmd) {
610 case BLKTRACESETUP:
611 bdevname(bdev, b);
612 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
613 break;
614 case BLKTRACESTART:
615 start = 1;
616 case BLKTRACESTOP:
617 ret = blk_trace_startstop(q, start);
618 break;
619 case BLKTRACETEARDOWN:
620 ret = blk_trace_remove(q);
621 break;
622 default:
623 ret = -ENOTTY;
624 break;
625 }
626
627 mutex_unlock(&bdev->bd_mutex);
628 return ret;
629 }
630
631 /**
632 * blk_trace_shutdown: - stop and cleanup trace structures
633 * @q: the request queue associated with the device
634 *
635 **/
636 void blk_trace_shutdown(struct request_queue *q)
637 {
638 if (q->blk_trace) {
639 blk_trace_startstop(q, 0);
640 blk_trace_remove(q);
641 }
642 }
643
644 /*
645 * blktrace probes
646 */
647
648 /**
649 * blk_add_trace_rq - Add a trace for a request oriented action
650 * @q: queue the io is for
651 * @rq: the source request
652 * @what: the action
653 *
654 * Description:
655 * Records an action against a request. Will log the bio offset + size.
656 *
657 **/
658 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
659 u32 what)
660 {
661 struct blk_trace *bt = q->blk_trace;
662 int rw = rq->cmd_flags & 0x03;
663
664 if (likely(!bt))
665 return;
666
667 if (blk_discard_rq(rq))
668 rw |= (1 << BIO_RW_DISCARD);
669
670 if (blk_pc_request(rq)) {
671 what |= BLK_TC_ACT(BLK_TC_PC);
672 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
673 what, rq->errors, rq->cmd_len, rq->cmd);
674 } else {
675 what |= BLK_TC_ACT(BLK_TC_FS);
676 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
677 what, rq->errors, 0, NULL);
678 }
679 }
680
681 static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq)
682 {
683 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
684 }
685
686 static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq)
687 {
688 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
689 }
690
691 static void blk_add_trace_rq_issue(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(struct request_queue *q,
697 struct request *rq)
698 {
699 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
700 }
701
702 static void blk_add_trace_rq_complete(struct request_queue *q,
703 struct request *rq)
704 {
705 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
706 }
707
708 /**
709 * blk_add_trace_bio - Add a trace for a bio oriented action
710 * @q: queue the io is for
711 * @bio: the source bio
712 * @what: the action
713 *
714 * Description:
715 * Records an action against a bio. Will log the bio offset + size.
716 *
717 **/
718 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
719 u32 what)
720 {
721 struct blk_trace *bt = q->blk_trace;
722
723 if (likely(!bt))
724 return;
725
726 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
727 !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
728 }
729
730 static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio)
731 {
732 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
733 }
734
735 static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio)
736 {
737 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
738 }
739
740 static void blk_add_trace_bio_backmerge(struct request_queue *q,
741 struct bio *bio)
742 {
743 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
744 }
745
746 static void blk_add_trace_bio_frontmerge(struct request_queue *q,
747 struct bio *bio)
748 {
749 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
750 }
751
752 static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio)
753 {
754 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
755 }
756
757 static void blk_add_trace_getrq(struct request_queue *q,
758 struct bio *bio, int rw)
759 {
760 if (bio)
761 blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
762 else {
763 struct blk_trace *bt = q->blk_trace;
764
765 if (bt)
766 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
767 }
768 }
769
770
771 static void blk_add_trace_sleeprq(struct request_queue *q,
772 struct bio *bio, int rw)
773 {
774 if (bio)
775 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
776 else {
777 struct blk_trace *bt = q->blk_trace;
778
779 if (bt)
780 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
781 0, 0, NULL);
782 }
783 }
784
785 static void blk_add_trace_plug(struct request_queue *q)
786 {
787 struct blk_trace *bt = q->blk_trace;
788
789 if (bt)
790 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
791 }
792
793 static void blk_add_trace_unplug_io(struct request_queue *q)
794 {
795 struct blk_trace *bt = q->blk_trace;
796
797 if (bt) {
798 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
799 __be64 rpdu = cpu_to_be64(pdu);
800
801 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
802 sizeof(rpdu), &rpdu);
803 }
804 }
805
806 static void blk_add_trace_unplug_timer(struct request_queue *q)
807 {
808 struct blk_trace *bt = q->blk_trace;
809
810 if (bt) {
811 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
812 __be64 rpdu = cpu_to_be64(pdu);
813
814 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
815 sizeof(rpdu), &rpdu);
816 }
817 }
818
819 static void blk_add_trace_split(struct request_queue *q, struct bio *bio,
820 unsigned int pdu)
821 {
822 struct blk_trace *bt = q->blk_trace;
823
824 if (bt) {
825 __be64 rpdu = cpu_to_be64(pdu);
826
827 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
828 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
829 sizeof(rpdu), &rpdu);
830 }
831 }
832
833 /**
834 * blk_add_trace_remap - Add a trace for a remap operation
835 * @q: queue the io is for
836 * @bio: the source bio
837 * @dev: target device
838 * @from: source sector
839 *
840 * Description:
841 * Device mapper or raid target sometimes need to split a bio because
842 * it spans a stripe (or similar). Add a trace for that action.
843 *
844 **/
845 static void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
846 dev_t dev, sector_t from)
847 {
848 struct blk_trace *bt = q->blk_trace;
849 struct blk_io_trace_remap r;
850
851 if (likely(!bt))
852 return;
853
854 r.device_from = cpu_to_be32(dev);
855 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
856 r.sector_from = cpu_to_be64(from);
857
858 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
859 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
860 sizeof(r), &r);
861 }
862
863 /**
864 * blk_add_driver_data - Add binary message with driver-specific data
865 * @q: queue the io is for
866 * @rq: io request
867 * @data: driver-specific data
868 * @len: length of driver-specific data
869 *
870 * Description:
871 * Some drivers might want to write driver-specific data per request.
872 *
873 **/
874 void blk_add_driver_data(struct request_queue *q,
875 struct request *rq,
876 void *data, size_t len)
877 {
878 struct blk_trace *bt = q->blk_trace;
879
880 if (likely(!bt))
881 return;
882
883 if (blk_pc_request(rq))
884 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
885 BLK_TA_DRV_DATA, rq->errors, len, data);
886 else
887 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
888 BLK_TA_DRV_DATA, rq->errors, len, data);
889 }
890 EXPORT_SYMBOL_GPL(blk_add_driver_data);
891
892 static void blk_register_tracepoints(void)
893 {
894 int ret;
895
896 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort);
897 WARN_ON(ret);
898 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert);
899 WARN_ON(ret);
900 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue);
901 WARN_ON(ret);
902 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue);
903 WARN_ON(ret);
904 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete);
905 WARN_ON(ret);
906 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce);
907 WARN_ON(ret);
908 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete);
909 WARN_ON(ret);
910 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
911 WARN_ON(ret);
912 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
913 WARN_ON(ret);
914 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue);
915 WARN_ON(ret);
916 ret = register_trace_block_getrq(blk_add_trace_getrq);
917 WARN_ON(ret);
918 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq);
919 WARN_ON(ret);
920 ret = register_trace_block_plug(blk_add_trace_plug);
921 WARN_ON(ret);
922 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer);
923 WARN_ON(ret);
924 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io);
925 WARN_ON(ret);
926 ret = register_trace_block_split(blk_add_trace_split);
927 WARN_ON(ret);
928 ret = register_trace_block_remap(blk_add_trace_remap);
929 WARN_ON(ret);
930 }
931
932 static void blk_unregister_tracepoints(void)
933 {
934 unregister_trace_block_remap(blk_add_trace_remap);
935 unregister_trace_block_split(blk_add_trace_split);
936 unregister_trace_block_unplug_io(blk_add_trace_unplug_io);
937 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer);
938 unregister_trace_block_plug(blk_add_trace_plug);
939 unregister_trace_block_sleeprq(blk_add_trace_sleeprq);
940 unregister_trace_block_getrq(blk_add_trace_getrq);
941 unregister_trace_block_bio_queue(blk_add_trace_bio_queue);
942 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
943 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
944 unregister_trace_block_bio_complete(blk_add_trace_bio_complete);
945 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce);
946 unregister_trace_block_rq_complete(blk_add_trace_rq_complete);
947 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue);
948 unregister_trace_block_rq_issue(blk_add_trace_rq_issue);
949 unregister_trace_block_rq_insert(blk_add_trace_rq_insert);
950 unregister_trace_block_rq_abort(blk_add_trace_rq_abort);
951
952 tracepoint_synchronize_unregister();
953 }
954
955 /*
956 * struct blk_io_tracer formatting routines
957 */
958
959 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
960 {
961 int i = 0;
962 int tc = t->action >> BLK_TC_SHIFT;
963
964 if (t->action == BLK_TN_MESSAGE) {
965 rwbs[i++] = 'N';
966 goto out;
967 }
968
969 if (tc & BLK_TC_DISCARD)
970 rwbs[i++] = 'D';
971 else if (tc & BLK_TC_WRITE)
972 rwbs[i++] = 'W';
973 else if (t->bytes)
974 rwbs[i++] = 'R';
975 else
976 rwbs[i++] = 'N';
977
978 if (tc & BLK_TC_AHEAD)
979 rwbs[i++] = 'A';
980 if (tc & BLK_TC_BARRIER)
981 rwbs[i++] = 'B';
982 if (tc & BLK_TC_SYNC)
983 rwbs[i++] = 'S';
984 if (tc & BLK_TC_META)
985 rwbs[i++] = 'M';
986 out:
987 rwbs[i] = '\0';
988 }
989
990 static inline
991 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
992 {
993 return (const struct blk_io_trace *)ent;
994 }
995
996 static inline const void *pdu_start(const struct trace_entry *ent)
997 {
998 return te_blk_io_trace(ent) + 1;
999 }
1000
1001 static inline u32 t_action(const struct trace_entry *ent)
1002 {
1003 return te_blk_io_trace(ent)->action;
1004 }
1005
1006 static inline u32 t_bytes(const struct trace_entry *ent)
1007 {
1008 return te_blk_io_trace(ent)->bytes;
1009 }
1010
1011 static inline u32 t_sec(const struct trace_entry *ent)
1012 {
1013 return te_blk_io_trace(ent)->bytes >> 9;
1014 }
1015
1016 static inline unsigned long long t_sector(const struct trace_entry *ent)
1017 {
1018 return te_blk_io_trace(ent)->sector;
1019 }
1020
1021 static inline __u16 t_error(const struct trace_entry *ent)
1022 {
1023 return te_blk_io_trace(ent)->error;
1024 }
1025
1026 static __u64 get_pdu_int(const struct trace_entry *ent)
1027 {
1028 const __u64 *val = pdu_start(ent);
1029 return be64_to_cpu(*val);
1030 }
1031
1032 static void get_pdu_remap(const struct trace_entry *ent,
1033 struct blk_io_trace_remap *r)
1034 {
1035 const struct blk_io_trace_remap *__r = pdu_start(ent);
1036 __u64 sector_from = __r->sector_from;
1037
1038 r->device_from = be32_to_cpu(__r->device_from);
1039 r->device_to = be32_to_cpu(__r->device_to);
1040 r->sector_from = be64_to_cpu(sector_from);
1041 }
1042
1043 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1044
1045 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1046 {
1047 char rwbs[6];
1048 unsigned long long ts = iter->ts;
1049 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1050 unsigned secs = (unsigned long)ts;
1051 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1052
1053 fill_rwbs(rwbs, t);
1054
1055 return trace_seq_printf(&iter->seq,
1056 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1057 MAJOR(t->device), MINOR(t->device), iter->cpu,
1058 secs, nsec_rem, iter->ent->pid, act, rwbs);
1059 }
1060
1061 static int blk_log_action(struct trace_iterator *iter, const char *act)
1062 {
1063 char rwbs[6];
1064 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1065
1066 fill_rwbs(rwbs, t);
1067 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1068 MAJOR(t->device), MINOR(t->device), act, rwbs);
1069 }
1070
1071 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1072 {
1073 const unsigned char *pdu_buf;
1074 int pdu_len;
1075 int i, end, ret;
1076
1077 pdu_buf = pdu_start(ent);
1078 pdu_len = te_blk_io_trace(ent)->pdu_len;
1079
1080 if (!pdu_len)
1081 return 1;
1082
1083 /* find the last zero that needs to be printed */
1084 for (end = pdu_len - 1; end >= 0; end--)
1085 if (pdu_buf[end])
1086 break;
1087 end++;
1088
1089 if (!trace_seq_putc(s, '('))
1090 return 0;
1091
1092 for (i = 0; i < pdu_len; i++) {
1093
1094 ret = trace_seq_printf(s, "%s%02x",
1095 i == 0 ? "" : " ", pdu_buf[i]);
1096 if (!ret)
1097 return ret;
1098
1099 /*
1100 * stop when the rest is just zeroes and indicate so
1101 * with a ".." appended
1102 */
1103 if (i == end && end != pdu_len - 1)
1104 return trace_seq_puts(s, " ..) ");
1105 }
1106
1107 return trace_seq_puts(s, ") ");
1108 }
1109
1110 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1111 {
1112 char cmd[TASK_COMM_LEN];
1113
1114 trace_find_cmdline(ent->pid, cmd);
1115
1116 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1117 int ret;
1118
1119 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1120 if (!ret)
1121 return 0;
1122 ret = blk_log_dump_pdu(s, ent);
1123 if (!ret)
1124 return 0;
1125 return trace_seq_printf(s, "[%s]\n", cmd);
1126 } else {
1127 if (t_sec(ent))
1128 return trace_seq_printf(s, "%llu + %u [%s]\n",
1129 t_sector(ent), t_sec(ent), cmd);
1130 return trace_seq_printf(s, "[%s]\n", cmd);
1131 }
1132 }
1133
1134 static int blk_log_with_error(struct trace_seq *s,
1135 const struct trace_entry *ent)
1136 {
1137 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1138 int ret;
1139
1140 ret = blk_log_dump_pdu(s, ent);
1141 if (ret)
1142 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1143 return 0;
1144 } else {
1145 if (t_sec(ent))
1146 return trace_seq_printf(s, "%llu + %u [%d]\n",
1147 t_sector(ent),
1148 t_sec(ent), t_error(ent));
1149 return trace_seq_printf(s, "%llu [%d]\n",
1150 t_sector(ent), t_error(ent));
1151 }
1152 }
1153
1154 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1155 {
1156 struct blk_io_trace_remap r = { .device_from = 0, };
1157
1158 get_pdu_remap(ent, &r);
1159 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1160 t_sector(ent), t_sec(ent),
1161 MAJOR(r.device_from), MINOR(r.device_from),
1162 (unsigned long long)r.sector_from);
1163 }
1164
1165 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1166 {
1167 char cmd[TASK_COMM_LEN];
1168
1169 trace_find_cmdline(ent->pid, cmd);
1170
1171 return trace_seq_printf(s, "[%s]\n", cmd);
1172 }
1173
1174 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1175 {
1176 char cmd[TASK_COMM_LEN];
1177
1178 trace_find_cmdline(ent->pid, cmd);
1179
1180 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1181 }
1182
1183 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1184 {
1185 char cmd[TASK_COMM_LEN];
1186
1187 trace_find_cmdline(ent->pid, cmd);
1188
1189 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1190 get_pdu_int(ent), cmd);
1191 }
1192
1193 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1194 {
1195 int ret;
1196 const struct blk_io_trace *t = te_blk_io_trace(ent);
1197
1198 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1199 if (ret)
1200 return trace_seq_putc(s, '\n');
1201 return ret;
1202 }
1203
1204 /*
1205 * struct tracer operations
1206 */
1207
1208 static void blk_tracer_print_header(struct seq_file *m)
1209 {
1210 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1211 return;
1212 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1213 "# | | | | | |\n");
1214 }
1215
1216 static void blk_tracer_start(struct trace_array *tr)
1217 {
1218 blk_tracer_enabled = true;
1219 }
1220
1221 static int blk_tracer_init(struct trace_array *tr)
1222 {
1223 blk_tr = tr;
1224 blk_tracer_start(tr);
1225 return 0;
1226 }
1227
1228 static void blk_tracer_stop(struct trace_array *tr)
1229 {
1230 blk_tracer_enabled = false;
1231 }
1232
1233 static void blk_tracer_reset(struct trace_array *tr)
1234 {
1235 blk_tracer_stop(tr);
1236 }
1237
1238 static const struct {
1239 const char *act[2];
1240 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1241 } what2act[] = {
1242 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1243 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1244 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1245 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1246 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1247 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1248 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1249 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1250 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1251 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1252 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1253 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1254 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1255 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1256 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1257 };
1258
1259 static enum print_line_t print_one_line(struct trace_iterator *iter,
1260 bool classic)
1261 {
1262 struct trace_seq *s = &iter->seq;
1263 const struct blk_io_trace *t;
1264 u16 what;
1265 int ret;
1266 bool long_act;
1267 blk_log_action_t *log_action;
1268
1269 t = te_blk_io_trace(iter->ent);
1270 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1271 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1272 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1273
1274 if (t->action == BLK_TN_MESSAGE) {
1275 ret = log_action(iter, long_act ? "message" : "m");
1276 if (ret)
1277 ret = blk_log_msg(s, iter->ent);
1278 goto out;
1279 }
1280
1281 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1282 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1283 else {
1284 ret = log_action(iter, what2act[what].act[long_act]);
1285 if (ret)
1286 ret = what2act[what].print(s, iter->ent);
1287 }
1288 out:
1289 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1290 }
1291
1292 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1293 int flags)
1294 {
1295 return print_one_line(iter, false);
1296 }
1297
1298 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1299 {
1300 struct trace_seq *s = &iter->seq;
1301 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1302 const int offset = offsetof(struct blk_io_trace, sector);
1303 struct blk_io_trace old = {
1304 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1305 .time = iter->ts,
1306 };
1307
1308 if (!trace_seq_putmem(s, &old, offset))
1309 return 0;
1310 return trace_seq_putmem(s, &t->sector,
1311 sizeof(old) - offset + t->pdu_len);
1312 }
1313
1314 static enum print_line_t
1315 blk_trace_event_print_binary(struct trace_iterator *iter, int flags)
1316 {
1317 return blk_trace_synthesize_old_trace(iter) ?
1318 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1319 }
1320
1321 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1322 {
1323 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1324 return TRACE_TYPE_UNHANDLED;
1325
1326 return print_one_line(iter, true);
1327 }
1328
1329 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1330 {
1331 /* don't output context-info for blk_classic output */
1332 if (bit == TRACE_BLK_OPT_CLASSIC) {
1333 if (set)
1334 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1335 else
1336 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1337 }
1338 return 0;
1339 }
1340
1341 static struct tracer blk_tracer __read_mostly = {
1342 .name = "blk",
1343 .init = blk_tracer_init,
1344 .reset = blk_tracer_reset,
1345 .start = blk_tracer_start,
1346 .stop = blk_tracer_stop,
1347 .print_header = blk_tracer_print_header,
1348 .print_line = blk_tracer_print_line,
1349 .flags = &blk_tracer_flags,
1350 .set_flag = blk_tracer_set_flag,
1351 };
1352
1353 static struct trace_event trace_blk_event = {
1354 .type = TRACE_BLK,
1355 .trace = blk_trace_event_print,
1356 .binary = blk_trace_event_print_binary,
1357 };
1358
1359 static int __init init_blk_tracer(void)
1360 {
1361 if (!register_ftrace_event(&trace_blk_event)) {
1362 pr_warning("Warning: could not register block events\n");
1363 return 1;
1364 }
1365
1366 if (register_tracer(&blk_tracer) != 0) {
1367 pr_warning("Warning: could not register the block tracer\n");
1368 unregister_ftrace_event(&trace_blk_event);
1369 return 1;
1370 }
1371
1372 return 0;
1373 }
1374
1375 device_initcall(init_blk_tracer);
1376
1377 static int blk_trace_remove_queue(struct request_queue *q)
1378 {
1379 struct blk_trace *bt;
1380
1381 bt = xchg(&q->blk_trace, NULL);
1382 if (bt == NULL)
1383 return -EINVAL;
1384
1385 if (atomic_dec_and_test(&blk_probes_ref))
1386 blk_unregister_tracepoints();
1387
1388 blk_trace_free(bt);
1389 return 0;
1390 }
1391
1392 /*
1393 * Setup everything required to start tracing
1394 */
1395 static int blk_trace_setup_queue(struct request_queue *q,
1396 struct block_device *bdev)
1397 {
1398 struct blk_trace *old_bt, *bt = NULL;
1399 int ret = -ENOMEM;
1400
1401 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1402 if (!bt)
1403 return -ENOMEM;
1404
1405 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1406 if (!bt->msg_data)
1407 goto free_bt;
1408
1409 bt->dev = bdev->bd_dev;
1410 bt->act_mask = (u16)-1;
1411
1412 blk_trace_setup_lba(bt, bdev);
1413
1414 old_bt = xchg(&q->blk_trace, bt);
1415 if (old_bt != NULL) {
1416 (void)xchg(&q->blk_trace, old_bt);
1417 ret = -EBUSY;
1418 goto free_bt;
1419 }
1420
1421 if (atomic_inc_return(&blk_probes_ref) == 1)
1422 blk_register_tracepoints();
1423 return 0;
1424
1425 free_bt:
1426 blk_trace_free(bt);
1427 return ret;
1428 }
1429
1430 /*
1431 * sysfs interface to enable and configure tracing
1432 */
1433
1434 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1435 struct device_attribute *attr,
1436 char *buf);
1437 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1438 struct device_attribute *attr,
1439 const char *buf, size_t count);
1440 #define BLK_TRACE_DEVICE_ATTR(_name) \
1441 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1442 sysfs_blk_trace_attr_show, \
1443 sysfs_blk_trace_attr_store)
1444
1445 static BLK_TRACE_DEVICE_ATTR(enable);
1446 static BLK_TRACE_DEVICE_ATTR(act_mask);
1447 static BLK_TRACE_DEVICE_ATTR(pid);
1448 static BLK_TRACE_DEVICE_ATTR(start_lba);
1449 static BLK_TRACE_DEVICE_ATTR(end_lba);
1450
1451 static struct attribute *blk_trace_attrs[] = {
1452 &dev_attr_enable.attr,
1453 &dev_attr_act_mask.attr,
1454 &dev_attr_pid.attr,
1455 &dev_attr_start_lba.attr,
1456 &dev_attr_end_lba.attr,
1457 NULL
1458 };
1459
1460 struct attribute_group blk_trace_attr_group = {
1461 .name = "trace",
1462 .attrs = blk_trace_attrs,
1463 };
1464
1465 static const struct {
1466 int mask;
1467 const char *str;
1468 } mask_maps[] = {
1469 { BLK_TC_READ, "read" },
1470 { BLK_TC_WRITE, "write" },
1471 { BLK_TC_BARRIER, "barrier" },
1472 { BLK_TC_SYNC, "sync" },
1473 { BLK_TC_QUEUE, "queue" },
1474 { BLK_TC_REQUEUE, "requeue" },
1475 { BLK_TC_ISSUE, "issue" },
1476 { BLK_TC_COMPLETE, "complete" },
1477 { BLK_TC_FS, "fs" },
1478 { BLK_TC_PC, "pc" },
1479 { BLK_TC_AHEAD, "ahead" },
1480 { BLK_TC_META, "meta" },
1481 { BLK_TC_DISCARD, "discard" },
1482 { BLK_TC_DRV_DATA, "drv_data" },
1483 };
1484
1485 static int blk_trace_str2mask(const char *str)
1486 {
1487 int i;
1488 int mask = 0;
1489 char *buf, *s, *token;
1490
1491 buf = kstrdup(str, GFP_KERNEL);
1492 if (buf == NULL)
1493 return -ENOMEM;
1494 s = strstrip(buf);
1495
1496 while (1) {
1497 token = strsep(&s, ",");
1498 if (token == NULL)
1499 break;
1500
1501 if (*token == '\0')
1502 continue;
1503
1504 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1505 if (strcasecmp(token, mask_maps[i].str) == 0) {
1506 mask |= mask_maps[i].mask;
1507 break;
1508 }
1509 }
1510 if (i == ARRAY_SIZE(mask_maps)) {
1511 mask = -EINVAL;
1512 break;
1513 }
1514 }
1515 kfree(buf);
1516
1517 return mask;
1518 }
1519
1520 static ssize_t blk_trace_mask2str(char *buf, int mask)
1521 {
1522 int i;
1523 char *p = buf;
1524
1525 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1526 if (mask & mask_maps[i].mask) {
1527 p += sprintf(p, "%s%s",
1528 (p == buf) ? "" : ",", mask_maps[i].str);
1529 }
1530 }
1531 *p++ = '\n';
1532
1533 return p - buf;
1534 }
1535
1536 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1537 {
1538 if (bdev->bd_disk == NULL)
1539 return NULL;
1540
1541 return bdev_get_queue(bdev);
1542 }
1543
1544 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1545 struct device_attribute *attr,
1546 char *buf)
1547 {
1548 struct hd_struct *p = dev_to_part(dev);
1549 struct request_queue *q;
1550 struct block_device *bdev;
1551 ssize_t ret = -ENXIO;
1552
1553 lock_kernel();
1554 bdev = bdget(part_devt(p));
1555 if (bdev == NULL)
1556 goto out_unlock_kernel;
1557
1558 q = blk_trace_get_queue(bdev);
1559 if (q == NULL)
1560 goto out_bdput;
1561
1562 mutex_lock(&bdev->bd_mutex);
1563
1564 if (attr == &dev_attr_enable) {
1565 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1566 goto out_unlock_bdev;
1567 }
1568
1569 if (q->blk_trace == NULL)
1570 ret = sprintf(buf, "disabled\n");
1571 else if (attr == &dev_attr_act_mask)
1572 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1573 else if (attr == &dev_attr_pid)
1574 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1575 else if (attr == &dev_attr_start_lba)
1576 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1577 else if (attr == &dev_attr_end_lba)
1578 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1579
1580 out_unlock_bdev:
1581 mutex_unlock(&bdev->bd_mutex);
1582 out_bdput:
1583 bdput(bdev);
1584 out_unlock_kernel:
1585 unlock_kernel();
1586 return ret;
1587 }
1588
1589 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1590 struct device_attribute *attr,
1591 const char *buf, size_t count)
1592 {
1593 struct block_device *bdev;
1594 struct request_queue *q;
1595 struct hd_struct *p;
1596 u64 value;
1597 ssize_t ret = -EINVAL;
1598
1599 if (count == 0)
1600 goto out;
1601
1602 if (attr == &dev_attr_act_mask) {
1603 if (sscanf(buf, "%llx", &value) != 1) {
1604 /* Assume it is a list of trace category names */
1605 ret = blk_trace_str2mask(buf);
1606 if (ret < 0)
1607 goto out;
1608 value = ret;
1609 }
1610 } else if (sscanf(buf, "%llu", &value) != 1)
1611 goto out;
1612
1613 ret = -ENXIO;
1614
1615 lock_kernel();
1616 p = dev_to_part(dev);
1617 bdev = bdget(part_devt(p));
1618 if (bdev == NULL)
1619 goto out_unlock_kernel;
1620
1621 q = blk_trace_get_queue(bdev);
1622 if (q == NULL)
1623 goto out_bdput;
1624
1625 mutex_lock(&bdev->bd_mutex);
1626
1627 if (attr == &dev_attr_enable) {
1628 if (value)
1629 ret = blk_trace_setup_queue(q, bdev);
1630 else
1631 ret = blk_trace_remove_queue(q);
1632 goto out_unlock_bdev;
1633 }
1634
1635 ret = 0;
1636 if (q->blk_trace == NULL)
1637 ret = blk_trace_setup_queue(q, bdev);
1638
1639 if (ret == 0) {
1640 if (attr == &dev_attr_act_mask)
1641 q->blk_trace->act_mask = value;
1642 else if (attr == &dev_attr_pid)
1643 q->blk_trace->pid = value;
1644 else if (attr == &dev_attr_start_lba)
1645 q->blk_trace->start_lba = value;
1646 else if (attr == &dev_attr_end_lba)
1647 q->blk_trace->end_lba = value;
1648 }
1649
1650 out_unlock_bdev:
1651 mutex_unlock(&bdev->bd_mutex);
1652 out_bdput:
1653 bdput(bdev);
1654 out_unlock_kernel:
1655 unlock_kernel();
1656 out:
1657 return ret ? ret : count;
1658 }
1659
1660 int blk_trace_init_sysfs(struct device *dev)
1661 {
1662 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1663 }
1664
1665 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1666
1667 #ifdef CONFIG_EVENT_TRACING
1668
1669 void blk_dump_cmd(char *buf, struct request *rq)
1670 {
1671 int i, end;
1672 int len = rq->cmd_len;
1673 unsigned char *cmd = rq->cmd;
1674
1675 if (!blk_pc_request(rq)) {
1676 buf[0] = '\0';
1677 return;
1678 }
1679
1680 for (end = len - 1; end >= 0; end--)
1681 if (cmd[end])
1682 break;
1683 end++;
1684
1685 for (i = 0; i < len; i++) {
1686 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1687 if (i == end && end != len - 1) {
1688 sprintf(buf, " ..");
1689 break;
1690 }
1691 }
1692 }
1693
1694 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1695 {
1696 int i = 0;
1697
1698 if (rw & WRITE)
1699 rwbs[i++] = 'W';
1700 else if (rw & 1 << BIO_RW_DISCARD)
1701 rwbs[i++] = 'D';
1702 else if (bytes)
1703 rwbs[i++] = 'R';
1704 else
1705 rwbs[i++] = 'N';
1706
1707 if (rw & 1 << BIO_RW_AHEAD)
1708 rwbs[i++] = 'A';
1709 if (rw & 1 << BIO_RW_BARRIER)
1710 rwbs[i++] = 'B';
1711 if (rw & 1 << BIO_RW_SYNCIO)
1712 rwbs[i++] = 'S';
1713 if (rw & 1 << BIO_RW_META)
1714 rwbs[i++] = 'M';
1715
1716 rwbs[i] = '\0';
1717 }
1718
1719 void blk_fill_rwbs_rq(char *rwbs, struct request *rq)
1720 {
1721 int rw = rq->cmd_flags & 0x03;
1722 int bytes;
1723
1724 if (blk_discard_rq(rq))
1725 rw |= (1 << BIO_RW_DISCARD);
1726
1727 bytes = blk_rq_bytes(rq);
1728
1729 blk_fill_rwbs(rwbs, rw, bytes);
1730 }
1731
1732 #endif /* CONFIG_EVENT_TRACING */
1733
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