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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux...
[deliverable/linux.git] / kernel / trace / blktrace.c
1 /*
2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
16 *
17 */
18 #include <linux/kernel.h>
19 #include <linux/blkdev.h>
20 #include <linux/blktrace_api.h>
21 #include <linux/percpu.h>
22 #include <linux/init.h>
23 #include <linux/mutex.h>
24 #include <linux/slab.h>
25 #include <linux/debugfs.h>
26 #include <linux/export.h>
27 #include <linux/time.h>
28 #include <linux/uaccess.h>
29
30 #include <trace/events/block.h>
31
32 #include "trace_output.h"
33
34 #ifdef CONFIG_BLK_DEV_IO_TRACE
35
36 static unsigned int blktrace_seq __read_mostly = 1;
37
38 static struct trace_array *blk_tr;
39 static bool blk_tracer_enabled __read_mostly;
40
41 /* Select an alternative, minimalistic output than the original one */
42 #define TRACE_BLK_OPT_CLASSIC 0x1
43
44 static struct tracer_opt blk_tracer_opts[] = {
45 /* Default disable the minimalistic output */
46 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
47 { }
48 };
49
50 static struct tracer_flags blk_tracer_flags = {
51 .val = 0,
52 .opts = blk_tracer_opts,
53 };
54
55 /* Global reference count of probes */
56 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
57
58 static void blk_register_tracepoints(void);
59 static void blk_unregister_tracepoints(void);
60
61 /*
62 * Send out a notify message.
63 */
64 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
65 const void *data, size_t len)
66 {
67 struct blk_io_trace *t;
68 struct ring_buffer_event *event = NULL;
69 struct ring_buffer *buffer = NULL;
70 int pc = 0;
71 int cpu = smp_processor_id();
72 bool blk_tracer = blk_tracer_enabled;
73
74 if (blk_tracer) {
75 buffer = blk_tr->buffer;
76 pc = preempt_count();
77 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
78 sizeof(*t) + len,
79 0, pc);
80 if (!event)
81 return;
82 t = ring_buffer_event_data(event);
83 goto record_it;
84 }
85
86 if (!bt->rchan)
87 return;
88
89 t = relay_reserve(bt->rchan, sizeof(*t) + len);
90 if (t) {
91 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
92 t->time = ktime_to_ns(ktime_get());
93 record_it:
94 t->device = bt->dev;
95 t->action = action;
96 t->pid = pid;
97 t->cpu = cpu;
98 t->pdu_len = len;
99 memcpy((void *) t + sizeof(*t), data, len);
100
101 if (blk_tracer)
102 trace_buffer_unlock_commit(buffer, event, 0, pc);
103 }
104 }
105
106 /*
107 * Send out a notify for this process, if we haven't done so since a trace
108 * started
109 */
110 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
111 {
112 tsk->btrace_seq = blktrace_seq;
113 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
114 }
115
116 static void trace_note_time(struct blk_trace *bt)
117 {
118 struct timespec now;
119 unsigned long flags;
120 u32 words[2];
121
122 getnstimeofday(&now);
123 words[0] = now.tv_sec;
124 words[1] = now.tv_nsec;
125
126 local_irq_save(flags);
127 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
128 local_irq_restore(flags);
129 }
130
131 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
132 {
133 int n;
134 va_list args;
135 unsigned long flags;
136 char *buf;
137
138 if (unlikely(bt->trace_state != Blktrace_running &&
139 !blk_tracer_enabled))
140 return;
141
142 /*
143 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
144 * message to the trace.
145 */
146 if (!(bt->act_mask & BLK_TC_NOTIFY))
147 return;
148
149 local_irq_save(flags);
150 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
151 va_start(args, fmt);
152 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
153 va_end(args);
154
155 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
156 local_irq_restore(flags);
157 }
158 EXPORT_SYMBOL_GPL(__trace_note_message);
159
160 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
161 pid_t pid)
162 {
163 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
164 return 1;
165 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
166 return 1;
167 if (bt->pid && pid != bt->pid)
168 return 1;
169
170 return 0;
171 }
172
173 /*
174 * Data direction bit lookup
175 */
176 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
177 BLK_TC_ACT(BLK_TC_WRITE) };
178
179 #define BLK_TC_RAHEAD BLK_TC_AHEAD
180
181 /* The ilog2() calls fall out because they're constant */
182 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
183 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
184
185 /*
186 * The worker for the various blk_add_trace*() types. Fills out a
187 * blk_io_trace structure and places it in a per-cpu subbuffer.
188 */
189 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
190 int rw, u32 what, int error, int pdu_len, void *pdu_data)
191 {
192 struct task_struct *tsk = current;
193 struct ring_buffer_event *event = NULL;
194 struct ring_buffer *buffer = NULL;
195 struct blk_io_trace *t;
196 unsigned long flags = 0;
197 unsigned long *sequence;
198 pid_t pid;
199 int cpu, pc = 0;
200 bool blk_tracer = blk_tracer_enabled;
201
202 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
203 return;
204
205 what |= ddir_act[rw & WRITE];
206 what |= MASK_TC_BIT(rw, SYNC);
207 what |= MASK_TC_BIT(rw, RAHEAD);
208 what |= MASK_TC_BIT(rw, META);
209 what |= MASK_TC_BIT(rw, DISCARD);
210 what |= MASK_TC_BIT(rw, FLUSH);
211 what |= MASK_TC_BIT(rw, FUA);
212
213 pid = tsk->pid;
214 if (act_log_check(bt, what, sector, pid))
215 return;
216 cpu = raw_smp_processor_id();
217
218 if (blk_tracer) {
219 tracing_record_cmdline(current);
220
221 buffer = blk_tr->buffer;
222 pc = preempt_count();
223 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
224 sizeof(*t) + pdu_len,
225 0, pc);
226 if (!event)
227 return;
228 t = ring_buffer_event_data(event);
229 goto record_it;
230 }
231
232 /*
233 * A word about the locking here - we disable interrupts to reserve
234 * some space in the relay per-cpu buffer, to prevent an irq
235 * from coming in and stepping on our toes.
236 */
237 local_irq_save(flags);
238
239 if (unlikely(tsk->btrace_seq != blktrace_seq))
240 trace_note_tsk(bt, tsk);
241
242 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
243 if (t) {
244 sequence = per_cpu_ptr(bt->sequence, cpu);
245
246 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
247 t->sequence = ++(*sequence);
248 t->time = ktime_to_ns(ktime_get());
249 record_it:
250 /*
251 * These two are not needed in ftrace as they are in the
252 * generic trace_entry, filled by tracing_generic_entry_update,
253 * but for the trace_event->bin() synthesizer benefit we do it
254 * here too.
255 */
256 t->cpu = cpu;
257 t->pid = pid;
258
259 t->sector = sector;
260 t->bytes = bytes;
261 t->action = what;
262 t->device = bt->dev;
263 t->error = error;
264 t->pdu_len = pdu_len;
265
266 if (pdu_len)
267 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
268
269 if (blk_tracer) {
270 trace_buffer_unlock_commit(buffer, event, 0, pc);
271 return;
272 }
273 }
274
275 local_irq_restore(flags);
276 }
277
278 static struct dentry *blk_tree_root;
279 static DEFINE_MUTEX(blk_tree_mutex);
280
281 static void blk_trace_free(struct blk_trace *bt)
282 {
283 debugfs_remove(bt->msg_file);
284 debugfs_remove(bt->dropped_file);
285 relay_close(bt->rchan);
286 debugfs_remove(bt->dir);
287 free_percpu(bt->sequence);
288 free_percpu(bt->msg_data);
289 kfree(bt);
290 }
291
292 static void blk_trace_cleanup(struct blk_trace *bt)
293 {
294 blk_trace_free(bt);
295 if (atomic_dec_and_test(&blk_probes_ref))
296 blk_unregister_tracepoints();
297 }
298
299 int blk_trace_remove(struct request_queue *q)
300 {
301 struct blk_trace *bt;
302
303 bt = xchg(&q->blk_trace, NULL);
304 if (!bt)
305 return -EINVAL;
306
307 if (bt->trace_state != Blktrace_running)
308 blk_trace_cleanup(bt);
309
310 return 0;
311 }
312 EXPORT_SYMBOL_GPL(blk_trace_remove);
313
314 static int blk_dropped_open(struct inode *inode, struct file *filp)
315 {
316 filp->private_data = inode->i_private;
317
318 return 0;
319 }
320
321 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
322 size_t count, loff_t *ppos)
323 {
324 struct blk_trace *bt = filp->private_data;
325 char buf[16];
326
327 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
328
329 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
330 }
331
332 static const struct file_operations blk_dropped_fops = {
333 .owner = THIS_MODULE,
334 .open = blk_dropped_open,
335 .read = blk_dropped_read,
336 .llseek = default_llseek,
337 };
338
339 static int blk_msg_open(struct inode *inode, struct file *filp)
340 {
341 filp->private_data = inode->i_private;
342
343 return 0;
344 }
345
346 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
347 size_t count, loff_t *ppos)
348 {
349 char *msg;
350 struct blk_trace *bt;
351
352 if (count >= BLK_TN_MAX_MSG)
353 return -EINVAL;
354
355 msg = kmalloc(count + 1, GFP_KERNEL);
356 if (msg == NULL)
357 return -ENOMEM;
358
359 if (copy_from_user(msg, buffer, count)) {
360 kfree(msg);
361 return -EFAULT;
362 }
363
364 msg[count] = '\0';
365 bt = filp->private_data;
366 __trace_note_message(bt, "%s", msg);
367 kfree(msg);
368
369 return count;
370 }
371
372 static const struct file_operations blk_msg_fops = {
373 .owner = THIS_MODULE,
374 .open = blk_msg_open,
375 .write = blk_msg_write,
376 .llseek = noop_llseek,
377 };
378
379 /*
380 * Keep track of how many times we encountered a full subbuffer, to aid
381 * the user space app in telling how many lost events there were.
382 */
383 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
384 void *prev_subbuf, size_t prev_padding)
385 {
386 struct blk_trace *bt;
387
388 if (!relay_buf_full(buf))
389 return 1;
390
391 bt = buf->chan->private_data;
392 atomic_inc(&bt->dropped);
393 return 0;
394 }
395
396 static int blk_remove_buf_file_callback(struct dentry *dentry)
397 {
398 debugfs_remove(dentry);
399
400 return 0;
401 }
402
403 static struct dentry *blk_create_buf_file_callback(const char *filename,
404 struct dentry *parent,
405 int mode,
406 struct rchan_buf *buf,
407 int *is_global)
408 {
409 return debugfs_create_file(filename, mode, parent, buf,
410 &relay_file_operations);
411 }
412
413 static struct rchan_callbacks blk_relay_callbacks = {
414 .subbuf_start = blk_subbuf_start_callback,
415 .create_buf_file = blk_create_buf_file_callback,
416 .remove_buf_file = blk_remove_buf_file_callback,
417 };
418
419 static void blk_trace_setup_lba(struct blk_trace *bt,
420 struct block_device *bdev)
421 {
422 struct hd_struct *part = NULL;
423
424 if (bdev)
425 part = bdev->bd_part;
426
427 if (part) {
428 bt->start_lba = part->start_sect;
429 bt->end_lba = part->start_sect + part->nr_sects;
430 } else {
431 bt->start_lba = 0;
432 bt->end_lba = -1ULL;
433 }
434 }
435
436 /*
437 * Setup everything required to start tracing
438 */
439 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
440 struct block_device *bdev,
441 struct blk_user_trace_setup *buts)
442 {
443 struct blk_trace *old_bt, *bt = NULL;
444 struct dentry *dir = NULL;
445 int ret, i;
446
447 if (!buts->buf_size || !buts->buf_nr)
448 return -EINVAL;
449
450 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
451 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
452
453 /*
454 * some device names have larger paths - convert the slashes
455 * to underscores for this to work as expected
456 */
457 for (i = 0; i < strlen(buts->name); i++)
458 if (buts->name[i] == '/')
459 buts->name[i] = '_';
460
461 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
462 if (!bt)
463 return -ENOMEM;
464
465 ret = -ENOMEM;
466 bt->sequence = alloc_percpu(unsigned long);
467 if (!bt->sequence)
468 goto err;
469
470 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
471 if (!bt->msg_data)
472 goto err;
473
474 ret = -ENOENT;
475
476 mutex_lock(&blk_tree_mutex);
477 if (!blk_tree_root) {
478 blk_tree_root = debugfs_create_dir("block", NULL);
479 if (!blk_tree_root) {
480 mutex_unlock(&blk_tree_mutex);
481 goto err;
482 }
483 }
484 mutex_unlock(&blk_tree_mutex);
485
486 dir = debugfs_create_dir(buts->name, blk_tree_root);
487
488 if (!dir)
489 goto err;
490
491 bt->dir = dir;
492 bt->dev = dev;
493 atomic_set(&bt->dropped, 0);
494
495 ret = -EIO;
496 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
497 &blk_dropped_fops);
498 if (!bt->dropped_file)
499 goto err;
500
501 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
502 if (!bt->msg_file)
503 goto err;
504
505 bt->rchan = relay_open("trace", dir, buts->buf_size,
506 buts->buf_nr, &blk_relay_callbacks, bt);
507 if (!bt->rchan)
508 goto err;
509
510 bt->act_mask = buts->act_mask;
511 if (!bt->act_mask)
512 bt->act_mask = (u16) -1;
513
514 blk_trace_setup_lba(bt, bdev);
515
516 /* overwrite with user settings */
517 if (buts->start_lba)
518 bt->start_lba = buts->start_lba;
519 if (buts->end_lba)
520 bt->end_lba = buts->end_lba;
521
522 bt->pid = buts->pid;
523 bt->trace_state = Blktrace_setup;
524
525 ret = -EBUSY;
526 old_bt = xchg(&q->blk_trace, bt);
527 if (old_bt) {
528 (void) xchg(&q->blk_trace, old_bt);
529 goto err;
530 }
531
532 if (atomic_inc_return(&blk_probes_ref) == 1)
533 blk_register_tracepoints();
534
535 return 0;
536 err:
537 blk_trace_free(bt);
538 return ret;
539 }
540
541 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
542 struct block_device *bdev,
543 char __user *arg)
544 {
545 struct blk_user_trace_setup buts;
546 int ret;
547
548 ret = copy_from_user(&buts, arg, sizeof(buts));
549 if (ret)
550 return -EFAULT;
551
552 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
553 if (ret)
554 return ret;
555
556 if (copy_to_user(arg, &buts, sizeof(buts))) {
557 blk_trace_remove(q);
558 return -EFAULT;
559 }
560 return 0;
561 }
562 EXPORT_SYMBOL_GPL(blk_trace_setup);
563
564 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
565 static int compat_blk_trace_setup(struct request_queue *q, char *name,
566 dev_t dev, struct block_device *bdev,
567 char __user *arg)
568 {
569 struct blk_user_trace_setup buts;
570 struct compat_blk_user_trace_setup cbuts;
571 int ret;
572
573 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
574 return -EFAULT;
575
576 buts = (struct blk_user_trace_setup) {
577 .act_mask = cbuts.act_mask,
578 .buf_size = cbuts.buf_size,
579 .buf_nr = cbuts.buf_nr,
580 .start_lba = cbuts.start_lba,
581 .end_lba = cbuts.end_lba,
582 .pid = cbuts.pid,
583 };
584 memcpy(&buts.name, &cbuts.name, 32);
585
586 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
587 if (ret)
588 return ret;
589
590 if (copy_to_user(arg, &buts.name, 32)) {
591 blk_trace_remove(q);
592 return -EFAULT;
593 }
594
595 return 0;
596 }
597 #endif
598
599 int blk_trace_startstop(struct request_queue *q, int start)
600 {
601 int ret;
602 struct blk_trace *bt = q->blk_trace;
603
604 if (bt == NULL)
605 return -EINVAL;
606
607 /*
608 * For starting a trace, we can transition from a setup or stopped
609 * trace. For stopping a trace, the state must be running
610 */
611 ret = -EINVAL;
612 if (start) {
613 if (bt->trace_state == Blktrace_setup ||
614 bt->trace_state == Blktrace_stopped) {
615 blktrace_seq++;
616 smp_mb();
617 bt->trace_state = Blktrace_running;
618
619 trace_note_time(bt);
620 ret = 0;
621 }
622 } else {
623 if (bt->trace_state == Blktrace_running) {
624 bt->trace_state = Blktrace_stopped;
625 relay_flush(bt->rchan);
626 ret = 0;
627 }
628 }
629
630 return ret;
631 }
632 EXPORT_SYMBOL_GPL(blk_trace_startstop);
633
634 /**
635 * blk_trace_ioctl: - handle the ioctls associated with tracing
636 * @bdev: the block device
637 * @cmd: the ioctl cmd
638 * @arg: the argument data, if any
639 *
640 **/
641 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
642 {
643 struct request_queue *q;
644 int ret, start = 0;
645 char b[BDEVNAME_SIZE];
646
647 q = bdev_get_queue(bdev);
648 if (!q)
649 return -ENXIO;
650
651 mutex_lock(&bdev->bd_mutex);
652
653 switch (cmd) {
654 case BLKTRACESETUP:
655 bdevname(bdev, b);
656 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
657 break;
658 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
659 case BLKTRACESETUP32:
660 bdevname(bdev, b);
661 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
662 break;
663 #endif
664 case BLKTRACESTART:
665 start = 1;
666 case BLKTRACESTOP:
667 ret = blk_trace_startstop(q, start);
668 break;
669 case BLKTRACETEARDOWN:
670 ret = blk_trace_remove(q);
671 break;
672 default:
673 ret = -ENOTTY;
674 break;
675 }
676
677 mutex_unlock(&bdev->bd_mutex);
678 return ret;
679 }
680
681 /**
682 * blk_trace_shutdown: - stop and cleanup trace structures
683 * @q: the request queue associated with the device
684 *
685 **/
686 void blk_trace_shutdown(struct request_queue *q)
687 {
688 if (q->blk_trace) {
689 blk_trace_startstop(q, 0);
690 blk_trace_remove(q);
691 }
692 }
693
694 /*
695 * blktrace probes
696 */
697
698 /**
699 * blk_add_trace_rq - Add a trace for a request oriented action
700 * @q: queue the io is for
701 * @rq: the source request
702 * @what: the action
703 *
704 * Description:
705 * Records an action against a request. Will log the bio offset + size.
706 *
707 **/
708 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
709 u32 what)
710 {
711 struct blk_trace *bt = q->blk_trace;
712
713 if (likely(!bt))
714 return;
715
716 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
717 what |= BLK_TC_ACT(BLK_TC_PC);
718 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
719 what, rq->errors, rq->cmd_len, rq->cmd);
720 } else {
721 what |= BLK_TC_ACT(BLK_TC_FS);
722 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
723 rq->cmd_flags, what, rq->errors, 0, NULL);
724 }
725 }
726
727 static void blk_add_trace_rq_abort(void *ignore,
728 struct request_queue *q, struct request *rq)
729 {
730 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
731 }
732
733 static void blk_add_trace_rq_insert(void *ignore,
734 struct request_queue *q, struct request *rq)
735 {
736 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
737 }
738
739 static void blk_add_trace_rq_issue(void *ignore,
740 struct request_queue *q, struct request *rq)
741 {
742 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
743 }
744
745 static void blk_add_trace_rq_requeue(void *ignore,
746 struct request_queue *q,
747 struct request *rq)
748 {
749 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
750 }
751
752 static void blk_add_trace_rq_complete(void *ignore,
753 struct request_queue *q,
754 struct request *rq)
755 {
756 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
757 }
758
759 /**
760 * blk_add_trace_bio - Add a trace for a bio oriented action
761 * @q: queue the io is for
762 * @bio: the source bio
763 * @what: the action
764 * @error: error, if any
765 *
766 * Description:
767 * Records an action against a bio. Will log the bio offset + size.
768 *
769 **/
770 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
771 u32 what, int error)
772 {
773 struct blk_trace *bt = q->blk_trace;
774
775 if (likely(!bt))
776 return;
777
778 if (!error && !bio_flagged(bio, BIO_UPTODATE))
779 error = EIO;
780
781 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
782 error, 0, NULL);
783 }
784
785 static void blk_add_trace_bio_bounce(void *ignore,
786 struct request_queue *q, struct bio *bio)
787 {
788 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
789 }
790
791 static void blk_add_trace_bio_complete(void *ignore,
792 struct request_queue *q, struct bio *bio,
793 int error)
794 {
795 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
796 }
797
798 static void blk_add_trace_bio_backmerge(void *ignore,
799 struct request_queue *q,
800 struct bio *bio)
801 {
802 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
803 }
804
805 static void blk_add_trace_bio_frontmerge(void *ignore,
806 struct request_queue *q,
807 struct bio *bio)
808 {
809 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
810 }
811
812 static void blk_add_trace_bio_queue(void *ignore,
813 struct request_queue *q, struct bio *bio)
814 {
815 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
816 }
817
818 static void blk_add_trace_getrq(void *ignore,
819 struct request_queue *q,
820 struct bio *bio, int rw)
821 {
822 if (bio)
823 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
824 else {
825 struct blk_trace *bt = q->blk_trace;
826
827 if (bt)
828 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
829 }
830 }
831
832
833 static void blk_add_trace_sleeprq(void *ignore,
834 struct request_queue *q,
835 struct bio *bio, int rw)
836 {
837 if (bio)
838 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
839 else {
840 struct blk_trace *bt = q->blk_trace;
841
842 if (bt)
843 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
844 0, 0, NULL);
845 }
846 }
847
848 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
849 {
850 struct blk_trace *bt = q->blk_trace;
851
852 if (bt)
853 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
854 }
855
856 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
857 unsigned int depth, bool explicit)
858 {
859 struct blk_trace *bt = q->blk_trace;
860
861 if (bt) {
862 __be64 rpdu = cpu_to_be64(depth);
863 u32 what;
864
865 if (explicit)
866 what = BLK_TA_UNPLUG_IO;
867 else
868 what = BLK_TA_UNPLUG_TIMER;
869
870 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
871 }
872 }
873
874 static void blk_add_trace_split(void *ignore,
875 struct request_queue *q, struct bio *bio,
876 unsigned int pdu)
877 {
878 struct blk_trace *bt = q->blk_trace;
879
880 if (bt) {
881 __be64 rpdu = cpu_to_be64(pdu);
882
883 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
884 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
885 sizeof(rpdu), &rpdu);
886 }
887 }
888
889 /**
890 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
891 * @ignore: trace callback data parameter (not used)
892 * @q: queue the io is for
893 * @bio: the source bio
894 * @dev: target device
895 * @from: source sector
896 *
897 * Description:
898 * Device mapper or raid target sometimes need to split a bio because
899 * it spans a stripe (or similar). Add a trace for that action.
900 *
901 **/
902 static void blk_add_trace_bio_remap(void *ignore,
903 struct request_queue *q, struct bio *bio,
904 dev_t dev, sector_t from)
905 {
906 struct blk_trace *bt = q->blk_trace;
907 struct blk_io_trace_remap r;
908
909 if (likely(!bt))
910 return;
911
912 r.device_from = cpu_to_be32(dev);
913 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
914 r.sector_from = cpu_to_be64(from);
915
916 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
917 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
918 sizeof(r), &r);
919 }
920
921 /**
922 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
923 * @ignore: trace callback data parameter (not used)
924 * @q: queue the io is for
925 * @rq: the source request
926 * @dev: target device
927 * @from: source sector
928 *
929 * Description:
930 * Device mapper remaps request to other devices.
931 * Add a trace for that action.
932 *
933 **/
934 static void blk_add_trace_rq_remap(void *ignore,
935 struct request_queue *q,
936 struct request *rq, dev_t dev,
937 sector_t from)
938 {
939 struct blk_trace *bt = q->blk_trace;
940 struct blk_io_trace_remap r;
941
942 if (likely(!bt))
943 return;
944
945 r.device_from = cpu_to_be32(dev);
946 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
947 r.sector_from = cpu_to_be64(from);
948
949 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
950 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
951 sizeof(r), &r);
952 }
953
954 /**
955 * blk_add_driver_data - Add binary message with driver-specific data
956 * @q: queue the io is for
957 * @rq: io request
958 * @data: driver-specific data
959 * @len: length of driver-specific data
960 *
961 * Description:
962 * Some drivers might want to write driver-specific data per request.
963 *
964 **/
965 void blk_add_driver_data(struct request_queue *q,
966 struct request *rq,
967 void *data, size_t len)
968 {
969 struct blk_trace *bt = q->blk_trace;
970
971 if (likely(!bt))
972 return;
973
974 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
975 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
976 BLK_TA_DRV_DATA, rq->errors, len, data);
977 else
978 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
979 BLK_TA_DRV_DATA, rq->errors, len, data);
980 }
981 EXPORT_SYMBOL_GPL(blk_add_driver_data);
982
983 static void blk_register_tracepoints(void)
984 {
985 int ret;
986
987 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
988 WARN_ON(ret);
989 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
990 WARN_ON(ret);
991 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
992 WARN_ON(ret);
993 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
994 WARN_ON(ret);
995 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1006 WARN_ON(ret);
1007 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1008 WARN_ON(ret);
1009 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1010 WARN_ON(ret);
1011 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1012 WARN_ON(ret);
1013 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1014 WARN_ON(ret);
1015 ret = register_trace_block_split(blk_add_trace_split, NULL);
1016 WARN_ON(ret);
1017 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1018 WARN_ON(ret);
1019 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1020 WARN_ON(ret);
1021 }
1022
1023 static void blk_unregister_tracepoints(void)
1024 {
1025 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1026 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1027 unregister_trace_block_split(blk_add_trace_split, NULL);
1028 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1029 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1030 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1031 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1032 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1033 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1034 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1035 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1036 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1037 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1038 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1039 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1040 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1041 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1042
1043 tracepoint_synchronize_unregister();
1044 }
1045
1046 /*
1047 * struct blk_io_tracer formatting routines
1048 */
1049
1050 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1051 {
1052 int i = 0;
1053 int tc = t->action >> BLK_TC_SHIFT;
1054
1055 if (t->action == BLK_TN_MESSAGE) {
1056 rwbs[i++] = 'N';
1057 goto out;
1058 }
1059
1060 if (tc & BLK_TC_FLUSH)
1061 rwbs[i++] = 'F';
1062
1063 if (tc & BLK_TC_DISCARD)
1064 rwbs[i++] = 'D';
1065 else if (tc & BLK_TC_WRITE)
1066 rwbs[i++] = 'W';
1067 else if (t->bytes)
1068 rwbs[i++] = 'R';
1069 else
1070 rwbs[i++] = 'N';
1071
1072 if (tc & BLK_TC_FUA)
1073 rwbs[i++] = 'F';
1074 if (tc & BLK_TC_AHEAD)
1075 rwbs[i++] = 'A';
1076 if (tc & BLK_TC_SYNC)
1077 rwbs[i++] = 'S';
1078 if (tc & BLK_TC_META)
1079 rwbs[i++] = 'M';
1080 out:
1081 rwbs[i] = '\0';
1082 }
1083
1084 static inline
1085 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1086 {
1087 return (const struct blk_io_trace *)ent;
1088 }
1089
1090 static inline const void *pdu_start(const struct trace_entry *ent)
1091 {
1092 return te_blk_io_trace(ent) + 1;
1093 }
1094
1095 static inline u32 t_action(const struct trace_entry *ent)
1096 {
1097 return te_blk_io_trace(ent)->action;
1098 }
1099
1100 static inline u32 t_bytes(const struct trace_entry *ent)
1101 {
1102 return te_blk_io_trace(ent)->bytes;
1103 }
1104
1105 static inline u32 t_sec(const struct trace_entry *ent)
1106 {
1107 return te_blk_io_trace(ent)->bytes >> 9;
1108 }
1109
1110 static inline unsigned long long t_sector(const struct trace_entry *ent)
1111 {
1112 return te_blk_io_trace(ent)->sector;
1113 }
1114
1115 static inline __u16 t_error(const struct trace_entry *ent)
1116 {
1117 return te_blk_io_trace(ent)->error;
1118 }
1119
1120 static __u64 get_pdu_int(const struct trace_entry *ent)
1121 {
1122 const __u64 *val = pdu_start(ent);
1123 return be64_to_cpu(*val);
1124 }
1125
1126 static void get_pdu_remap(const struct trace_entry *ent,
1127 struct blk_io_trace_remap *r)
1128 {
1129 const struct blk_io_trace_remap *__r = pdu_start(ent);
1130 __u64 sector_from = __r->sector_from;
1131
1132 r->device_from = be32_to_cpu(__r->device_from);
1133 r->device_to = be32_to_cpu(__r->device_to);
1134 r->sector_from = be64_to_cpu(sector_from);
1135 }
1136
1137 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1138
1139 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1140 {
1141 char rwbs[RWBS_LEN];
1142 unsigned long long ts = iter->ts;
1143 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1144 unsigned secs = (unsigned long)ts;
1145 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1146
1147 fill_rwbs(rwbs, t);
1148
1149 return trace_seq_printf(&iter->seq,
1150 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1151 MAJOR(t->device), MINOR(t->device), iter->cpu,
1152 secs, nsec_rem, iter->ent->pid, act, rwbs);
1153 }
1154
1155 static int blk_log_action(struct trace_iterator *iter, const char *act)
1156 {
1157 char rwbs[RWBS_LEN];
1158 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1159
1160 fill_rwbs(rwbs, t);
1161 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1162 MAJOR(t->device), MINOR(t->device), act, rwbs);
1163 }
1164
1165 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1166 {
1167 const unsigned char *pdu_buf;
1168 int pdu_len;
1169 int i, end, ret;
1170
1171 pdu_buf = pdu_start(ent);
1172 pdu_len = te_blk_io_trace(ent)->pdu_len;
1173
1174 if (!pdu_len)
1175 return 1;
1176
1177 /* find the last zero that needs to be printed */
1178 for (end = pdu_len - 1; end >= 0; end--)
1179 if (pdu_buf[end])
1180 break;
1181 end++;
1182
1183 if (!trace_seq_putc(s, '('))
1184 return 0;
1185
1186 for (i = 0; i < pdu_len; i++) {
1187
1188 ret = trace_seq_printf(s, "%s%02x",
1189 i == 0 ? "" : " ", pdu_buf[i]);
1190 if (!ret)
1191 return ret;
1192
1193 /*
1194 * stop when the rest is just zeroes and indicate so
1195 * with a ".." appended
1196 */
1197 if (i == end && end != pdu_len - 1)
1198 return trace_seq_puts(s, " ..) ");
1199 }
1200
1201 return trace_seq_puts(s, ") ");
1202 }
1203
1204 static int blk_log_generic(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 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1211 int ret;
1212
1213 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1214 if (!ret)
1215 return 0;
1216 ret = blk_log_dump_pdu(s, ent);
1217 if (!ret)
1218 return 0;
1219 return trace_seq_printf(s, "[%s]\n", cmd);
1220 } else {
1221 if (t_sec(ent))
1222 return trace_seq_printf(s, "%llu + %u [%s]\n",
1223 t_sector(ent), t_sec(ent), cmd);
1224 return trace_seq_printf(s, "[%s]\n", cmd);
1225 }
1226 }
1227
1228 static int blk_log_with_error(struct trace_seq *s,
1229 const struct trace_entry *ent)
1230 {
1231 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1232 int ret;
1233
1234 ret = blk_log_dump_pdu(s, ent);
1235 if (ret)
1236 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1237 return 0;
1238 } else {
1239 if (t_sec(ent))
1240 return trace_seq_printf(s, "%llu + %u [%d]\n",
1241 t_sector(ent),
1242 t_sec(ent), t_error(ent));
1243 return trace_seq_printf(s, "%llu [%d]\n",
1244 t_sector(ent), t_error(ent));
1245 }
1246 }
1247
1248 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1249 {
1250 struct blk_io_trace_remap r = { .device_from = 0, };
1251
1252 get_pdu_remap(ent, &r);
1253 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1254 t_sector(ent), t_sec(ent),
1255 MAJOR(r.device_from), MINOR(r.device_from),
1256 (unsigned long long)r.sector_from);
1257 }
1258
1259 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1260 {
1261 char cmd[TASK_COMM_LEN];
1262
1263 trace_find_cmdline(ent->pid, cmd);
1264
1265 return trace_seq_printf(s, "[%s]\n", cmd);
1266 }
1267
1268 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1269 {
1270 char cmd[TASK_COMM_LEN];
1271
1272 trace_find_cmdline(ent->pid, cmd);
1273
1274 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1275 }
1276
1277 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1278 {
1279 char cmd[TASK_COMM_LEN];
1280
1281 trace_find_cmdline(ent->pid, cmd);
1282
1283 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1284 get_pdu_int(ent), cmd);
1285 }
1286
1287 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1288 {
1289 int ret;
1290 const struct blk_io_trace *t = te_blk_io_trace(ent);
1291
1292 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1293 if (ret)
1294 return trace_seq_putc(s, '\n');
1295 return ret;
1296 }
1297
1298 /*
1299 * struct tracer operations
1300 */
1301
1302 static void blk_tracer_print_header(struct seq_file *m)
1303 {
1304 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1305 return;
1306 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1307 "# | | | | | |\n");
1308 }
1309
1310 static void blk_tracer_start(struct trace_array *tr)
1311 {
1312 blk_tracer_enabled = true;
1313 }
1314
1315 static int blk_tracer_init(struct trace_array *tr)
1316 {
1317 blk_tr = tr;
1318 blk_tracer_start(tr);
1319 return 0;
1320 }
1321
1322 static void blk_tracer_stop(struct trace_array *tr)
1323 {
1324 blk_tracer_enabled = false;
1325 }
1326
1327 static void blk_tracer_reset(struct trace_array *tr)
1328 {
1329 blk_tracer_stop(tr);
1330 }
1331
1332 static const struct {
1333 const char *act[2];
1334 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1335 } what2act[] = {
1336 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1337 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1338 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1339 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1340 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1341 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1342 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1343 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1344 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1345 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1346 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1347 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1348 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1349 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1350 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1351 };
1352
1353 static enum print_line_t print_one_line(struct trace_iterator *iter,
1354 bool classic)
1355 {
1356 struct trace_seq *s = &iter->seq;
1357 const struct blk_io_trace *t;
1358 u16 what;
1359 int ret;
1360 bool long_act;
1361 blk_log_action_t *log_action;
1362
1363 t = te_blk_io_trace(iter->ent);
1364 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1365 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1366 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1367
1368 if (t->action == BLK_TN_MESSAGE) {
1369 ret = log_action(iter, long_act ? "message" : "m");
1370 if (ret)
1371 ret = blk_log_msg(s, iter->ent);
1372 goto out;
1373 }
1374
1375 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1376 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1377 else {
1378 ret = log_action(iter, what2act[what].act[long_act]);
1379 if (ret)
1380 ret = what2act[what].print(s, iter->ent);
1381 }
1382 out:
1383 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1384 }
1385
1386 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1387 int flags, struct trace_event *event)
1388 {
1389 return print_one_line(iter, false);
1390 }
1391
1392 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1393 {
1394 struct trace_seq *s = &iter->seq;
1395 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1396 const int offset = offsetof(struct blk_io_trace, sector);
1397 struct blk_io_trace old = {
1398 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1399 .time = iter->ts,
1400 };
1401
1402 if (!trace_seq_putmem(s, &old, offset))
1403 return 0;
1404 return trace_seq_putmem(s, &t->sector,
1405 sizeof(old) - offset + t->pdu_len);
1406 }
1407
1408 static enum print_line_t
1409 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1410 struct trace_event *event)
1411 {
1412 return blk_trace_synthesize_old_trace(iter) ?
1413 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1414 }
1415
1416 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1417 {
1418 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1419 return TRACE_TYPE_UNHANDLED;
1420
1421 return print_one_line(iter, true);
1422 }
1423
1424 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1425 {
1426 /* don't output context-info for blk_classic output */
1427 if (bit == TRACE_BLK_OPT_CLASSIC) {
1428 if (set)
1429 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1430 else
1431 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1432 }
1433 return 0;
1434 }
1435
1436 static struct tracer blk_tracer __read_mostly = {
1437 .name = "blk",
1438 .init = blk_tracer_init,
1439 .reset = blk_tracer_reset,
1440 .start = blk_tracer_start,
1441 .stop = blk_tracer_stop,
1442 .print_header = blk_tracer_print_header,
1443 .print_line = blk_tracer_print_line,
1444 .flags = &blk_tracer_flags,
1445 .set_flag = blk_tracer_set_flag,
1446 };
1447
1448 static struct trace_event_functions trace_blk_event_funcs = {
1449 .trace = blk_trace_event_print,
1450 .binary = blk_trace_event_print_binary,
1451 };
1452
1453 static struct trace_event trace_blk_event = {
1454 .type = TRACE_BLK,
1455 .funcs = &trace_blk_event_funcs,
1456 };
1457
1458 static int __init init_blk_tracer(void)
1459 {
1460 if (!register_ftrace_event(&trace_blk_event)) {
1461 pr_warning("Warning: could not register block events\n");
1462 return 1;
1463 }
1464
1465 if (register_tracer(&blk_tracer) != 0) {
1466 pr_warning("Warning: could not register the block tracer\n");
1467 unregister_ftrace_event(&trace_blk_event);
1468 return 1;
1469 }
1470
1471 return 0;
1472 }
1473
1474 device_initcall(init_blk_tracer);
1475
1476 static int blk_trace_remove_queue(struct request_queue *q)
1477 {
1478 struct blk_trace *bt;
1479
1480 bt = xchg(&q->blk_trace, NULL);
1481 if (bt == NULL)
1482 return -EINVAL;
1483
1484 if (atomic_dec_and_test(&blk_probes_ref))
1485 blk_unregister_tracepoints();
1486
1487 blk_trace_free(bt);
1488 return 0;
1489 }
1490
1491 /*
1492 * Setup everything required to start tracing
1493 */
1494 static int blk_trace_setup_queue(struct request_queue *q,
1495 struct block_device *bdev)
1496 {
1497 struct blk_trace *old_bt, *bt = NULL;
1498 int ret = -ENOMEM;
1499
1500 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1501 if (!bt)
1502 return -ENOMEM;
1503
1504 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1505 if (!bt->msg_data)
1506 goto free_bt;
1507
1508 bt->dev = bdev->bd_dev;
1509 bt->act_mask = (u16)-1;
1510
1511 blk_trace_setup_lba(bt, bdev);
1512
1513 old_bt = xchg(&q->blk_trace, bt);
1514 if (old_bt != NULL) {
1515 (void)xchg(&q->blk_trace, old_bt);
1516 ret = -EBUSY;
1517 goto free_bt;
1518 }
1519
1520 if (atomic_inc_return(&blk_probes_ref) == 1)
1521 blk_register_tracepoints();
1522 return 0;
1523
1524 free_bt:
1525 blk_trace_free(bt);
1526 return ret;
1527 }
1528
1529 /*
1530 * sysfs interface to enable and configure tracing
1531 */
1532
1533 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1534 struct device_attribute *attr,
1535 char *buf);
1536 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1537 struct device_attribute *attr,
1538 const char *buf, size_t count);
1539 #define BLK_TRACE_DEVICE_ATTR(_name) \
1540 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1541 sysfs_blk_trace_attr_show, \
1542 sysfs_blk_trace_attr_store)
1543
1544 static BLK_TRACE_DEVICE_ATTR(enable);
1545 static BLK_TRACE_DEVICE_ATTR(act_mask);
1546 static BLK_TRACE_DEVICE_ATTR(pid);
1547 static BLK_TRACE_DEVICE_ATTR(start_lba);
1548 static BLK_TRACE_DEVICE_ATTR(end_lba);
1549
1550 static struct attribute *blk_trace_attrs[] = {
1551 &dev_attr_enable.attr,
1552 &dev_attr_act_mask.attr,
1553 &dev_attr_pid.attr,
1554 &dev_attr_start_lba.attr,
1555 &dev_attr_end_lba.attr,
1556 NULL
1557 };
1558
1559 struct attribute_group blk_trace_attr_group = {
1560 .name = "trace",
1561 .attrs = blk_trace_attrs,
1562 };
1563
1564 static const struct {
1565 int mask;
1566 const char *str;
1567 } mask_maps[] = {
1568 { BLK_TC_READ, "read" },
1569 { BLK_TC_WRITE, "write" },
1570 { BLK_TC_FLUSH, "flush" },
1571 { BLK_TC_SYNC, "sync" },
1572 { BLK_TC_QUEUE, "queue" },
1573 { BLK_TC_REQUEUE, "requeue" },
1574 { BLK_TC_ISSUE, "issue" },
1575 { BLK_TC_COMPLETE, "complete" },
1576 { BLK_TC_FS, "fs" },
1577 { BLK_TC_PC, "pc" },
1578 { BLK_TC_AHEAD, "ahead" },
1579 { BLK_TC_META, "meta" },
1580 { BLK_TC_DISCARD, "discard" },
1581 { BLK_TC_DRV_DATA, "drv_data" },
1582 { BLK_TC_FUA, "fua" },
1583 };
1584
1585 static int blk_trace_str2mask(const char *str)
1586 {
1587 int i;
1588 int mask = 0;
1589 char *buf, *s, *token;
1590
1591 buf = kstrdup(str, GFP_KERNEL);
1592 if (buf == NULL)
1593 return -ENOMEM;
1594 s = strstrip(buf);
1595
1596 while (1) {
1597 token = strsep(&s, ",");
1598 if (token == NULL)
1599 break;
1600
1601 if (*token == '\0')
1602 continue;
1603
1604 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1605 if (strcasecmp(token, mask_maps[i].str) == 0) {
1606 mask |= mask_maps[i].mask;
1607 break;
1608 }
1609 }
1610 if (i == ARRAY_SIZE(mask_maps)) {
1611 mask = -EINVAL;
1612 break;
1613 }
1614 }
1615 kfree(buf);
1616
1617 return mask;
1618 }
1619
1620 static ssize_t blk_trace_mask2str(char *buf, int mask)
1621 {
1622 int i;
1623 char *p = buf;
1624
1625 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1626 if (mask & mask_maps[i].mask) {
1627 p += sprintf(p, "%s%s",
1628 (p == buf) ? "" : ",", mask_maps[i].str);
1629 }
1630 }
1631 *p++ = '\n';
1632
1633 return p - buf;
1634 }
1635
1636 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1637 {
1638 if (bdev->bd_disk == NULL)
1639 return NULL;
1640
1641 return bdev_get_queue(bdev);
1642 }
1643
1644 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1645 struct device_attribute *attr,
1646 char *buf)
1647 {
1648 struct hd_struct *p = dev_to_part(dev);
1649 struct request_queue *q;
1650 struct block_device *bdev;
1651 ssize_t ret = -ENXIO;
1652
1653 bdev = bdget(part_devt(p));
1654 if (bdev == NULL)
1655 goto out;
1656
1657 q = blk_trace_get_queue(bdev);
1658 if (q == NULL)
1659 goto out_bdput;
1660
1661 mutex_lock(&bdev->bd_mutex);
1662
1663 if (attr == &dev_attr_enable) {
1664 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1665 goto out_unlock_bdev;
1666 }
1667
1668 if (q->blk_trace == NULL)
1669 ret = sprintf(buf, "disabled\n");
1670 else if (attr == &dev_attr_act_mask)
1671 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1672 else if (attr == &dev_attr_pid)
1673 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1674 else if (attr == &dev_attr_start_lba)
1675 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1676 else if (attr == &dev_attr_end_lba)
1677 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1678
1679 out_unlock_bdev:
1680 mutex_unlock(&bdev->bd_mutex);
1681 out_bdput:
1682 bdput(bdev);
1683 out:
1684 return ret;
1685 }
1686
1687 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1688 struct device_attribute *attr,
1689 const char *buf, size_t count)
1690 {
1691 struct block_device *bdev;
1692 struct request_queue *q;
1693 struct hd_struct *p;
1694 u64 value;
1695 ssize_t ret = -EINVAL;
1696
1697 if (count == 0)
1698 goto out;
1699
1700 if (attr == &dev_attr_act_mask) {
1701 if (sscanf(buf, "%llx", &value) != 1) {
1702 /* Assume it is a list of trace category names */
1703 ret = blk_trace_str2mask(buf);
1704 if (ret < 0)
1705 goto out;
1706 value = ret;
1707 }
1708 } else if (sscanf(buf, "%llu", &value) != 1)
1709 goto out;
1710
1711 ret = -ENXIO;
1712
1713 p = dev_to_part(dev);
1714 bdev = bdget(part_devt(p));
1715 if (bdev == NULL)
1716 goto out;
1717
1718 q = blk_trace_get_queue(bdev);
1719 if (q == NULL)
1720 goto out_bdput;
1721
1722 mutex_lock(&bdev->bd_mutex);
1723
1724 if (attr == &dev_attr_enable) {
1725 if (value)
1726 ret = blk_trace_setup_queue(q, bdev);
1727 else
1728 ret = blk_trace_remove_queue(q);
1729 goto out_unlock_bdev;
1730 }
1731
1732 ret = 0;
1733 if (q->blk_trace == NULL)
1734 ret = blk_trace_setup_queue(q, bdev);
1735
1736 if (ret == 0) {
1737 if (attr == &dev_attr_act_mask)
1738 q->blk_trace->act_mask = value;
1739 else if (attr == &dev_attr_pid)
1740 q->blk_trace->pid = value;
1741 else if (attr == &dev_attr_start_lba)
1742 q->blk_trace->start_lba = value;
1743 else if (attr == &dev_attr_end_lba)
1744 q->blk_trace->end_lba = value;
1745 }
1746
1747 out_unlock_bdev:
1748 mutex_unlock(&bdev->bd_mutex);
1749 out_bdput:
1750 bdput(bdev);
1751 out:
1752 return ret ? ret : count;
1753 }
1754
1755 int blk_trace_init_sysfs(struct device *dev)
1756 {
1757 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1758 }
1759
1760 void blk_trace_remove_sysfs(struct device *dev)
1761 {
1762 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1763 }
1764
1765 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1766
1767 #ifdef CONFIG_EVENT_TRACING
1768
1769 void blk_dump_cmd(char *buf, struct request *rq)
1770 {
1771 int i, end;
1772 int len = rq->cmd_len;
1773 unsigned char *cmd = rq->cmd;
1774
1775 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1776 buf[0] = '\0';
1777 return;
1778 }
1779
1780 for (end = len - 1; end >= 0; end--)
1781 if (cmd[end])
1782 break;
1783 end++;
1784
1785 for (i = 0; i < len; i++) {
1786 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1787 if (i == end && end != len - 1) {
1788 sprintf(buf, " ..");
1789 break;
1790 }
1791 }
1792 }
1793
1794 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1795 {
1796 int i = 0;
1797
1798 if (rw & REQ_FLUSH)
1799 rwbs[i++] = 'F';
1800
1801 if (rw & WRITE)
1802 rwbs[i++] = 'W';
1803 else if (rw & REQ_DISCARD)
1804 rwbs[i++] = 'D';
1805 else if (bytes)
1806 rwbs[i++] = 'R';
1807 else
1808 rwbs[i++] = 'N';
1809
1810 if (rw & REQ_FUA)
1811 rwbs[i++] = 'F';
1812 if (rw & REQ_RAHEAD)
1813 rwbs[i++] = 'A';
1814 if (rw & REQ_SYNC)
1815 rwbs[i++] = 'S';
1816 if (rw & REQ_META)
1817 rwbs[i++] = 'M';
1818 if (rw & REQ_SECURE)
1819 rwbs[i++] = 'E';
1820
1821 rwbs[i] = '\0';
1822 }
1823
1824 #endif /* CONFIG_EVENT_TRACING */
1825
Linux kernel - Deliverables
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