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Merge tag 'trace-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux...
[mirror_ubuntu-zesty-kernel.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 #include <linux/list.h>
30
31 #include <trace/events/block.h>
32
33 #include "trace_output.h"
34
35 #ifdef CONFIG_BLK_DEV_IO_TRACE
36
37 static unsigned int blktrace_seq __read_mostly = 1;
38
39 static struct trace_array *blk_tr;
40 static bool blk_tracer_enabled __read_mostly;
41
42 static LIST_HEAD(running_trace_list);
43 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
44
45 /* Select an alternative, minimalistic output than the original one */
46 #define TRACE_BLK_OPT_CLASSIC 0x1
47
48 static struct tracer_opt blk_tracer_opts[] = {
49 /* Default disable the minimalistic output */
50 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
51 { }
52 };
53
54 static struct tracer_flags blk_tracer_flags = {
55 .val = 0,
56 .opts = blk_tracer_opts,
57 };
58
59 /* Global reference count of probes */
60 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
61
62 static void blk_register_tracepoints(void);
63 static void blk_unregister_tracepoints(void);
64
65 /*
66 * Send out a notify message.
67 */
68 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
69 const void *data, size_t len)
70 {
71 struct blk_io_trace *t;
72 struct ring_buffer_event *event = NULL;
73 struct ring_buffer *buffer = NULL;
74 int pc = 0;
75 int cpu = smp_processor_id();
76 bool blk_tracer = blk_tracer_enabled;
77
78 if (blk_tracer) {
79 buffer = blk_tr->trace_buffer.buffer;
80 pc = preempt_count();
81 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
82 sizeof(*t) + len,
83 0, pc);
84 if (!event)
85 return;
86 t = ring_buffer_event_data(event);
87 goto record_it;
88 }
89
90 if (!bt->rchan)
91 return;
92
93 t = relay_reserve(bt->rchan, sizeof(*t) + len);
94 if (t) {
95 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
96 t->time = ktime_to_ns(ktime_get());
97 record_it:
98 t->device = bt->dev;
99 t->action = action;
100 t->pid = pid;
101 t->cpu = cpu;
102 t->pdu_len = len;
103 memcpy((void *) t + sizeof(*t), data, len);
104
105 if (blk_tracer)
106 trace_buffer_unlock_commit(buffer, event, 0, pc);
107 }
108 }
109
110 /*
111 * Send out a notify for this process, if we haven't done so since a trace
112 * started
113 */
114 static void trace_note_tsk(struct task_struct *tsk)
115 {
116 unsigned long flags;
117 struct blk_trace *bt;
118
119 tsk->btrace_seq = blktrace_seq;
120 spin_lock_irqsave(&running_trace_lock, flags);
121 list_for_each_entry(bt, &running_trace_list, running_list) {
122 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
123 sizeof(tsk->comm));
124 }
125 spin_unlock_irqrestore(&running_trace_lock, flags);
126 }
127
128 static void trace_note_time(struct blk_trace *bt)
129 {
130 struct timespec now;
131 unsigned long flags;
132 u32 words[2];
133
134 getnstimeofday(&now);
135 words[0] = now.tv_sec;
136 words[1] = now.tv_nsec;
137
138 local_irq_save(flags);
139 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
140 local_irq_restore(flags);
141 }
142
143 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
144 {
145 int n;
146 va_list args;
147 unsigned long flags;
148 char *buf;
149
150 if (unlikely(bt->trace_state != Blktrace_running &&
151 !blk_tracer_enabled))
152 return;
153
154 /*
155 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
156 * message to the trace.
157 */
158 if (!(bt->act_mask & BLK_TC_NOTIFY))
159 return;
160
161 local_irq_save(flags);
162 buf = this_cpu_ptr(bt->msg_data);
163 va_start(args, fmt);
164 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
165 va_end(args);
166
167 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
168 local_irq_restore(flags);
169 }
170 EXPORT_SYMBOL_GPL(__trace_note_message);
171
172 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
173 pid_t pid)
174 {
175 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
176 return 1;
177 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
178 return 1;
179 if (bt->pid && pid != bt->pid)
180 return 1;
181
182 return 0;
183 }
184
185 /*
186 * Data direction bit lookup
187 */
188 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
189 BLK_TC_ACT(BLK_TC_WRITE) };
190
191 #define BLK_TC_RAHEAD BLK_TC_AHEAD
192
193 /* The ilog2() calls fall out because they're constant */
194 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
195 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
196
197 /*
198 * The worker for the various blk_add_trace*() types. Fills out a
199 * blk_io_trace structure and places it in a per-cpu subbuffer.
200 */
201 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
202 int rw, u32 what, int error, int pdu_len, void *pdu_data)
203 {
204 struct task_struct *tsk = current;
205 struct ring_buffer_event *event = NULL;
206 struct ring_buffer *buffer = NULL;
207 struct blk_io_trace *t;
208 unsigned long flags = 0;
209 unsigned long *sequence;
210 pid_t pid;
211 int cpu, pc = 0;
212 bool blk_tracer = blk_tracer_enabled;
213
214 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
215 return;
216
217 what |= ddir_act[rw & WRITE];
218 what |= MASK_TC_BIT(rw, SYNC);
219 what |= MASK_TC_BIT(rw, RAHEAD);
220 what |= MASK_TC_BIT(rw, META);
221 what |= MASK_TC_BIT(rw, DISCARD);
222 what |= MASK_TC_BIT(rw, FLUSH);
223 what |= MASK_TC_BIT(rw, FUA);
224
225 pid = tsk->pid;
226 if (act_log_check(bt, what, sector, pid))
227 return;
228 cpu = raw_smp_processor_id();
229
230 if (blk_tracer) {
231 tracing_record_cmdline(current);
232
233 buffer = blk_tr->trace_buffer.buffer;
234 pc = preempt_count();
235 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
236 sizeof(*t) + pdu_len,
237 0, pc);
238 if (!event)
239 return;
240 t = ring_buffer_event_data(event);
241 goto record_it;
242 }
243
244 if (unlikely(tsk->btrace_seq != blktrace_seq))
245 trace_note_tsk(tsk);
246
247 /*
248 * A word about the locking here - we disable interrupts to reserve
249 * some space in the relay per-cpu buffer, to prevent an irq
250 * from coming in and stepping on our toes.
251 */
252 local_irq_save(flags);
253 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
254 if (t) {
255 sequence = per_cpu_ptr(bt->sequence, cpu);
256
257 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
258 t->sequence = ++(*sequence);
259 t->time = ktime_to_ns(ktime_get());
260 record_it:
261 /*
262 * These two are not needed in ftrace as they are in the
263 * generic trace_entry, filled by tracing_generic_entry_update,
264 * but for the trace_event->bin() synthesizer benefit we do it
265 * here too.
266 */
267 t->cpu = cpu;
268 t->pid = pid;
269
270 t->sector = sector;
271 t->bytes = bytes;
272 t->action = what;
273 t->device = bt->dev;
274 t->error = error;
275 t->pdu_len = pdu_len;
276
277 if (pdu_len)
278 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
279
280 if (blk_tracer) {
281 trace_buffer_unlock_commit(buffer, event, 0, pc);
282 return;
283 }
284 }
285
286 local_irq_restore(flags);
287 }
288
289 static struct dentry *blk_tree_root;
290 static DEFINE_MUTEX(blk_tree_mutex);
291
292 static void blk_trace_free(struct blk_trace *bt)
293 {
294 debugfs_remove(bt->msg_file);
295 debugfs_remove(bt->dropped_file);
296 relay_close(bt->rchan);
297 debugfs_remove(bt->dir);
298 free_percpu(bt->sequence);
299 free_percpu(bt->msg_data);
300 kfree(bt);
301 }
302
303 static void blk_trace_cleanup(struct blk_trace *bt)
304 {
305 blk_trace_free(bt);
306 if (atomic_dec_and_test(&blk_probes_ref))
307 blk_unregister_tracepoints();
308 }
309
310 int blk_trace_remove(struct request_queue *q)
311 {
312 struct blk_trace *bt;
313
314 bt = xchg(&q->blk_trace, NULL);
315 if (!bt)
316 return -EINVAL;
317
318 if (bt->trace_state != Blktrace_running)
319 blk_trace_cleanup(bt);
320
321 return 0;
322 }
323 EXPORT_SYMBOL_GPL(blk_trace_remove);
324
325 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
326 size_t count, loff_t *ppos)
327 {
328 struct blk_trace *bt = filp->private_data;
329 char buf[16];
330
331 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
332
333 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
334 }
335
336 static const struct file_operations blk_dropped_fops = {
337 .owner = THIS_MODULE,
338 .open = simple_open,
339 .read = blk_dropped_read,
340 .llseek = default_llseek,
341 };
342
343 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
344 size_t count, loff_t *ppos)
345 {
346 char *msg;
347 struct blk_trace *bt;
348
349 if (count >= BLK_TN_MAX_MSG)
350 return -EINVAL;
351
352 msg = kmalloc(count + 1, GFP_KERNEL);
353 if (msg == NULL)
354 return -ENOMEM;
355
356 if (copy_from_user(msg, buffer, count)) {
357 kfree(msg);
358 return -EFAULT;
359 }
360
361 msg[count] = '\0';
362 bt = filp->private_data;
363 __trace_note_message(bt, "%s", msg);
364 kfree(msg);
365
366 return count;
367 }
368
369 static const struct file_operations blk_msg_fops = {
370 .owner = THIS_MODULE,
371 .open = simple_open,
372 .write = blk_msg_write,
373 .llseek = noop_llseek,
374 };
375
376 /*
377 * Keep track of how many times we encountered a full subbuffer, to aid
378 * the user space app in telling how many lost events there were.
379 */
380 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
381 void *prev_subbuf, size_t prev_padding)
382 {
383 struct blk_trace *bt;
384
385 if (!relay_buf_full(buf))
386 return 1;
387
388 bt = buf->chan->private_data;
389 atomic_inc(&bt->dropped);
390 return 0;
391 }
392
393 static int blk_remove_buf_file_callback(struct dentry *dentry)
394 {
395 debugfs_remove(dentry);
396
397 return 0;
398 }
399
400 static struct dentry *blk_create_buf_file_callback(const char *filename,
401 struct dentry *parent,
402 umode_t mode,
403 struct rchan_buf *buf,
404 int *is_global)
405 {
406 return debugfs_create_file(filename, mode, parent, buf,
407 &relay_file_operations);
408 }
409
410 static struct rchan_callbacks blk_relay_callbacks = {
411 .subbuf_start = blk_subbuf_start_callback,
412 .create_buf_file = blk_create_buf_file_callback,
413 .remove_buf_file = blk_remove_buf_file_callback,
414 };
415
416 static void blk_trace_setup_lba(struct blk_trace *bt,
417 struct block_device *bdev)
418 {
419 struct hd_struct *part = NULL;
420
421 if (bdev)
422 part = bdev->bd_part;
423
424 if (part) {
425 bt->start_lba = part->start_sect;
426 bt->end_lba = part->start_sect + part->nr_sects;
427 } else {
428 bt->start_lba = 0;
429 bt->end_lba = -1ULL;
430 }
431 }
432
433 /*
434 * Setup everything required to start tracing
435 */
436 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
437 struct block_device *bdev,
438 struct blk_user_trace_setup *buts)
439 {
440 struct blk_trace *old_bt, *bt = NULL;
441 struct dentry *dir = NULL;
442 int ret, i;
443
444 if (!buts->buf_size || !buts->buf_nr)
445 return -EINVAL;
446
447 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
448 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
449
450 /*
451 * some device names have larger paths - convert the slashes
452 * to underscores for this to work as expected
453 */
454 for (i = 0; i < strlen(buts->name); i++)
455 if (buts->name[i] == '/')
456 buts->name[i] = '_';
457
458 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
459 if (!bt)
460 return -ENOMEM;
461
462 ret = -ENOMEM;
463 bt->sequence = alloc_percpu(unsigned long);
464 if (!bt->sequence)
465 goto err;
466
467 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
468 if (!bt->msg_data)
469 goto err;
470
471 ret = -ENOENT;
472
473 mutex_lock(&blk_tree_mutex);
474 if (!blk_tree_root) {
475 blk_tree_root = debugfs_create_dir("block", NULL);
476 if (!blk_tree_root) {
477 mutex_unlock(&blk_tree_mutex);
478 goto err;
479 }
480 }
481 mutex_unlock(&blk_tree_mutex);
482
483 dir = debugfs_create_dir(buts->name, blk_tree_root);
484
485 if (!dir)
486 goto err;
487
488 bt->dir = dir;
489 bt->dev = dev;
490 atomic_set(&bt->dropped, 0);
491 INIT_LIST_HEAD(&bt->running_list);
492
493 ret = -EIO;
494 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
495 &blk_dropped_fops);
496 if (!bt->dropped_file)
497 goto err;
498
499 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
500 if (!bt->msg_file)
501 goto err;
502
503 bt->rchan = relay_open("trace", dir, buts->buf_size,
504 buts->buf_nr, &blk_relay_callbacks, bt);
505 if (!bt->rchan)
506 goto err;
507
508 bt->act_mask = buts->act_mask;
509 if (!bt->act_mask)
510 bt->act_mask = (u16) -1;
511
512 blk_trace_setup_lba(bt, bdev);
513
514 /* overwrite with user settings */
515 if (buts->start_lba)
516 bt->start_lba = buts->start_lba;
517 if (buts->end_lba)
518 bt->end_lba = buts->end_lba;
519
520 bt->pid = buts->pid;
521 bt->trace_state = Blktrace_setup;
522
523 ret = -EBUSY;
524 old_bt = xchg(&q->blk_trace, bt);
525 if (old_bt) {
526 (void) xchg(&q->blk_trace, old_bt);
527 goto err;
528 }
529
530 if (atomic_inc_return(&blk_probes_ref) == 1)
531 blk_register_tracepoints();
532
533 return 0;
534 err:
535 blk_trace_free(bt);
536 return ret;
537 }
538
539 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
540 struct block_device *bdev,
541 char __user *arg)
542 {
543 struct blk_user_trace_setup buts;
544 int ret;
545
546 ret = copy_from_user(&buts, arg, sizeof(buts));
547 if (ret)
548 return -EFAULT;
549
550 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
551 if (ret)
552 return ret;
553
554 if (copy_to_user(arg, &buts, sizeof(buts))) {
555 blk_trace_remove(q);
556 return -EFAULT;
557 }
558 return 0;
559 }
560 EXPORT_SYMBOL_GPL(blk_trace_setup);
561
562 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
563 static int compat_blk_trace_setup(struct request_queue *q, char *name,
564 dev_t dev, struct block_device *bdev,
565 char __user *arg)
566 {
567 struct blk_user_trace_setup buts;
568 struct compat_blk_user_trace_setup cbuts;
569 int ret;
570
571 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
572 return -EFAULT;
573
574 buts = (struct blk_user_trace_setup) {
575 .act_mask = cbuts.act_mask,
576 .buf_size = cbuts.buf_size,
577 .buf_nr = cbuts.buf_nr,
578 .start_lba = cbuts.start_lba,
579 .end_lba = cbuts.end_lba,
580 .pid = cbuts.pid,
581 };
582
583 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
584 if (ret)
585 return ret;
586
587 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
588 blk_trace_remove(q);
589 return -EFAULT;
590 }
591
592 return 0;
593 }
594 #endif
595
596 int blk_trace_startstop(struct request_queue *q, int start)
597 {
598 int ret;
599 struct blk_trace *bt = q->blk_trace;
600
601 if (bt == NULL)
602 return -EINVAL;
603
604 /*
605 * For starting a trace, we can transition from a setup or stopped
606 * trace. For stopping a trace, the state must be running
607 */
608 ret = -EINVAL;
609 if (start) {
610 if (bt->trace_state == Blktrace_setup ||
611 bt->trace_state == Blktrace_stopped) {
612 blktrace_seq++;
613 smp_mb();
614 bt->trace_state = Blktrace_running;
615 spin_lock_irq(&running_trace_lock);
616 list_add(&bt->running_list, &running_trace_list);
617 spin_unlock_irq(&running_trace_lock);
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 spin_lock_irq(&running_trace_lock);
626 list_del_init(&bt->running_list);
627 spin_unlock_irq(&running_trace_lock);
628 relay_flush(bt->rchan);
629 ret = 0;
630 }
631 }
632
633 return ret;
634 }
635 EXPORT_SYMBOL_GPL(blk_trace_startstop);
636
637 /**
638 * blk_trace_ioctl: - handle the ioctls associated with tracing
639 * @bdev: the block device
640 * @cmd: the ioctl cmd
641 * @arg: the argument data, if any
642 *
643 **/
644 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
645 {
646 struct request_queue *q;
647 int ret, start = 0;
648 char b[BDEVNAME_SIZE];
649
650 q = bdev_get_queue(bdev);
651 if (!q)
652 return -ENXIO;
653
654 mutex_lock(&bdev->bd_mutex);
655
656 switch (cmd) {
657 case BLKTRACESETUP:
658 bdevname(bdev, b);
659 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
660 break;
661 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
662 case BLKTRACESETUP32:
663 bdevname(bdev, b);
664 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
665 break;
666 #endif
667 case BLKTRACESTART:
668 start = 1;
669 case BLKTRACESTOP:
670 ret = blk_trace_startstop(q, start);
671 break;
672 case BLKTRACETEARDOWN:
673 ret = blk_trace_remove(q);
674 break;
675 default:
676 ret = -ENOTTY;
677 break;
678 }
679
680 mutex_unlock(&bdev->bd_mutex);
681 return ret;
682 }
683
684 /**
685 * blk_trace_shutdown: - stop and cleanup trace structures
686 * @q: the request queue associated with the device
687 *
688 **/
689 void blk_trace_shutdown(struct request_queue *q)
690 {
691 if (q->blk_trace) {
692 blk_trace_startstop(q, 0);
693 blk_trace_remove(q);
694 }
695 }
696
697 /*
698 * blktrace probes
699 */
700
701 /**
702 * blk_add_trace_rq - Add a trace for a request oriented action
703 * @q: queue the io is for
704 * @rq: the source request
705 * @what: the action
706 *
707 * Description:
708 * Records an action against a request. Will log the bio offset + size.
709 *
710 **/
711 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
712 u32 what)
713 {
714 struct blk_trace *bt = q->blk_trace;
715
716 if (likely(!bt))
717 return;
718
719 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
720 what |= BLK_TC_ACT(BLK_TC_PC);
721 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
722 what, rq->errors, rq->cmd_len, rq->cmd);
723 } else {
724 what |= BLK_TC_ACT(BLK_TC_FS);
725 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
726 rq->cmd_flags, what, rq->errors, 0, NULL);
727 }
728 }
729
730 static void blk_add_trace_rq_abort(void *ignore,
731 struct request_queue *q, struct request *rq)
732 {
733 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
734 }
735
736 static void blk_add_trace_rq_insert(void *ignore,
737 struct request_queue *q, struct request *rq)
738 {
739 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
740 }
741
742 static void blk_add_trace_rq_issue(void *ignore,
743 struct request_queue *q, struct request *rq)
744 {
745 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
746 }
747
748 static void blk_add_trace_rq_requeue(void *ignore,
749 struct request_queue *q,
750 struct request *rq)
751 {
752 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
753 }
754
755 static void blk_add_trace_rq_complete(void *ignore,
756 struct request_queue *q,
757 struct request *rq)
758 {
759 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
760 }
761
762 /**
763 * blk_add_trace_bio - Add a trace for a bio oriented action
764 * @q: queue the io is for
765 * @bio: the source bio
766 * @what: the action
767 * @error: error, if any
768 *
769 * Description:
770 * Records an action against a bio. Will log the bio offset + size.
771 *
772 **/
773 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
774 u32 what, int error)
775 {
776 struct blk_trace *bt = q->blk_trace;
777
778 if (likely(!bt))
779 return;
780
781 if (!error && !bio_flagged(bio, BIO_UPTODATE))
782 error = EIO;
783
784 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
785 error, 0, NULL);
786 }
787
788 static void blk_add_trace_bio_bounce(void *ignore,
789 struct request_queue *q, struct bio *bio)
790 {
791 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
792 }
793
794 static void blk_add_trace_bio_complete(void *ignore,
795 struct request_queue *q, struct bio *bio,
796 int error)
797 {
798 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
799 }
800
801 static void blk_add_trace_bio_backmerge(void *ignore,
802 struct request_queue *q,
803 struct request *rq,
804 struct bio *bio)
805 {
806 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
807 }
808
809 static void blk_add_trace_bio_frontmerge(void *ignore,
810 struct request_queue *q,
811 struct request *rq,
812 struct bio *bio)
813 {
814 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
815 }
816
817 static void blk_add_trace_bio_queue(void *ignore,
818 struct request_queue *q, struct bio *bio)
819 {
820 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
821 }
822
823 static void blk_add_trace_getrq(void *ignore,
824 struct request_queue *q,
825 struct bio *bio, int rw)
826 {
827 if (bio)
828 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
829 else {
830 struct blk_trace *bt = q->blk_trace;
831
832 if (bt)
833 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
834 }
835 }
836
837
838 static void blk_add_trace_sleeprq(void *ignore,
839 struct request_queue *q,
840 struct bio *bio, int rw)
841 {
842 if (bio)
843 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
844 else {
845 struct blk_trace *bt = q->blk_trace;
846
847 if (bt)
848 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
849 0, 0, NULL);
850 }
851 }
852
853 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
854 {
855 struct blk_trace *bt = q->blk_trace;
856
857 if (bt)
858 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
859 }
860
861 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
862 unsigned int depth, bool explicit)
863 {
864 struct blk_trace *bt = q->blk_trace;
865
866 if (bt) {
867 __be64 rpdu = cpu_to_be64(depth);
868 u32 what;
869
870 if (explicit)
871 what = BLK_TA_UNPLUG_IO;
872 else
873 what = BLK_TA_UNPLUG_TIMER;
874
875 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
876 }
877 }
878
879 static void blk_add_trace_split(void *ignore,
880 struct request_queue *q, struct bio *bio,
881 unsigned int pdu)
882 {
883 struct blk_trace *bt = q->blk_trace;
884
885 if (bt) {
886 __be64 rpdu = cpu_to_be64(pdu);
887
888 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
889 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
890 sizeof(rpdu), &rpdu);
891 }
892 }
893
894 /**
895 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
896 * @ignore: trace callback data parameter (not used)
897 * @q: queue the io is for
898 * @bio: the source bio
899 * @dev: target device
900 * @from: source sector
901 *
902 * Description:
903 * Device mapper or raid target sometimes need to split a bio because
904 * it spans a stripe (or similar). Add a trace for that action.
905 *
906 **/
907 static void blk_add_trace_bio_remap(void *ignore,
908 struct request_queue *q, struct bio *bio,
909 dev_t dev, sector_t from)
910 {
911 struct blk_trace *bt = q->blk_trace;
912 struct blk_io_trace_remap r;
913
914 if (likely(!bt))
915 return;
916
917 r.device_from = cpu_to_be32(dev);
918 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
919 r.sector_from = cpu_to_be64(from);
920
921 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
922 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
923 sizeof(r), &r);
924 }
925
926 /**
927 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
928 * @ignore: trace callback data parameter (not used)
929 * @q: queue the io is for
930 * @rq: the source request
931 * @dev: target device
932 * @from: source sector
933 *
934 * Description:
935 * Device mapper remaps request to other devices.
936 * Add a trace for that action.
937 *
938 **/
939 static void blk_add_trace_rq_remap(void *ignore,
940 struct request_queue *q,
941 struct request *rq, dev_t dev,
942 sector_t from)
943 {
944 struct blk_trace *bt = q->blk_trace;
945 struct blk_io_trace_remap r;
946
947 if (likely(!bt))
948 return;
949
950 r.device_from = cpu_to_be32(dev);
951 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
952 r.sector_from = cpu_to_be64(from);
953
954 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
955 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
956 sizeof(r), &r);
957 }
958
959 /**
960 * blk_add_driver_data - Add binary message with driver-specific data
961 * @q: queue the io is for
962 * @rq: io request
963 * @data: driver-specific data
964 * @len: length of driver-specific data
965 *
966 * Description:
967 * Some drivers might want to write driver-specific data per request.
968 *
969 **/
970 void blk_add_driver_data(struct request_queue *q,
971 struct request *rq,
972 void *data, size_t len)
973 {
974 struct blk_trace *bt = q->blk_trace;
975
976 if (likely(!bt))
977 return;
978
979 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
980 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
981 BLK_TA_DRV_DATA, rq->errors, len, data);
982 else
983 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
984 BLK_TA_DRV_DATA, rq->errors, len, data);
985 }
986 EXPORT_SYMBOL_GPL(blk_add_driver_data);
987
988 static void blk_register_tracepoints(void)
989 {
990 int ret;
991
992 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
993 WARN_ON(ret);
994 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
995 WARN_ON(ret);
996 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
997 WARN_ON(ret);
998 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
999 WARN_ON(ret);
1000 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1001 WARN_ON(ret);
1002 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1003 WARN_ON(ret);
1004 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1005 WARN_ON(ret);
1006 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1007 WARN_ON(ret);
1008 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1009 WARN_ON(ret);
1010 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1011 WARN_ON(ret);
1012 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1013 WARN_ON(ret);
1014 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1015 WARN_ON(ret);
1016 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1017 WARN_ON(ret);
1018 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1019 WARN_ON(ret);
1020 ret = register_trace_block_split(blk_add_trace_split, NULL);
1021 WARN_ON(ret);
1022 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1023 WARN_ON(ret);
1024 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1025 WARN_ON(ret);
1026 }
1027
1028 static void blk_unregister_tracepoints(void)
1029 {
1030 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1031 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1032 unregister_trace_block_split(blk_add_trace_split, NULL);
1033 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1034 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1035 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1036 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1037 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1038 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1039 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1040 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1041 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1042 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1043 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1044 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1045 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1046 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1047
1048 tracepoint_synchronize_unregister();
1049 }
1050
1051 /*
1052 * struct blk_io_tracer formatting routines
1053 */
1054
1055 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1056 {
1057 int i = 0;
1058 int tc = t->action >> BLK_TC_SHIFT;
1059
1060 if (t->action == BLK_TN_MESSAGE) {
1061 rwbs[i++] = 'N';
1062 goto out;
1063 }
1064
1065 if (tc & BLK_TC_FLUSH)
1066 rwbs[i++] = 'F';
1067
1068 if (tc & BLK_TC_DISCARD)
1069 rwbs[i++] = 'D';
1070 else if (tc & BLK_TC_WRITE)
1071 rwbs[i++] = 'W';
1072 else if (t->bytes)
1073 rwbs[i++] = 'R';
1074 else
1075 rwbs[i++] = 'N';
1076
1077 if (tc & BLK_TC_FUA)
1078 rwbs[i++] = 'F';
1079 if (tc & BLK_TC_AHEAD)
1080 rwbs[i++] = 'A';
1081 if (tc & BLK_TC_SYNC)
1082 rwbs[i++] = 'S';
1083 if (tc & BLK_TC_META)
1084 rwbs[i++] = 'M';
1085 out:
1086 rwbs[i] = '\0';
1087 }
1088
1089 static inline
1090 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1091 {
1092 return (const struct blk_io_trace *)ent;
1093 }
1094
1095 static inline const void *pdu_start(const struct trace_entry *ent)
1096 {
1097 return te_blk_io_trace(ent) + 1;
1098 }
1099
1100 static inline u32 t_action(const struct trace_entry *ent)
1101 {
1102 return te_blk_io_trace(ent)->action;
1103 }
1104
1105 static inline u32 t_bytes(const struct trace_entry *ent)
1106 {
1107 return te_blk_io_trace(ent)->bytes;
1108 }
1109
1110 static inline u32 t_sec(const struct trace_entry *ent)
1111 {
1112 return te_blk_io_trace(ent)->bytes >> 9;
1113 }
1114
1115 static inline unsigned long long t_sector(const struct trace_entry *ent)
1116 {
1117 return te_blk_io_trace(ent)->sector;
1118 }
1119
1120 static inline __u16 t_error(const struct trace_entry *ent)
1121 {
1122 return te_blk_io_trace(ent)->error;
1123 }
1124
1125 static __u64 get_pdu_int(const struct trace_entry *ent)
1126 {
1127 const __u64 *val = pdu_start(ent);
1128 return be64_to_cpu(*val);
1129 }
1130
1131 static void get_pdu_remap(const struct trace_entry *ent,
1132 struct blk_io_trace_remap *r)
1133 {
1134 const struct blk_io_trace_remap *__r = pdu_start(ent);
1135 __u64 sector_from = __r->sector_from;
1136
1137 r->device_from = be32_to_cpu(__r->device_from);
1138 r->device_to = be32_to_cpu(__r->device_to);
1139 r->sector_from = be64_to_cpu(sector_from);
1140 }
1141
1142 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1143
1144 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1145 {
1146 char rwbs[RWBS_LEN];
1147 unsigned long long ts = iter->ts;
1148 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1149 unsigned secs = (unsigned long)ts;
1150 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1151
1152 fill_rwbs(rwbs, t);
1153
1154 return trace_seq_printf(&iter->seq,
1155 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1156 MAJOR(t->device), MINOR(t->device), iter->cpu,
1157 secs, nsec_rem, iter->ent->pid, act, rwbs);
1158 }
1159
1160 static int blk_log_action(struct trace_iterator *iter, const char *act)
1161 {
1162 char rwbs[RWBS_LEN];
1163 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1164
1165 fill_rwbs(rwbs, t);
1166 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1167 MAJOR(t->device), MINOR(t->device), act, rwbs);
1168 }
1169
1170 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1171 {
1172 const unsigned char *pdu_buf;
1173 int pdu_len;
1174 int i, end, ret;
1175
1176 pdu_buf = pdu_start(ent);
1177 pdu_len = te_blk_io_trace(ent)->pdu_len;
1178
1179 if (!pdu_len)
1180 return 1;
1181
1182 /* find the last zero that needs to be printed */
1183 for (end = pdu_len - 1; end >= 0; end--)
1184 if (pdu_buf[end])
1185 break;
1186 end++;
1187
1188 if (!trace_seq_putc(s, '('))
1189 return 0;
1190
1191 for (i = 0; i < pdu_len; i++) {
1192
1193 ret = trace_seq_printf(s, "%s%02x",
1194 i == 0 ? "" : " ", pdu_buf[i]);
1195 if (!ret)
1196 return ret;
1197
1198 /*
1199 * stop when the rest is just zeroes and indicate so
1200 * with a ".." appended
1201 */
1202 if (i == end && end != pdu_len - 1)
1203 return trace_seq_puts(s, " ..) ");
1204 }
1205
1206 return trace_seq_puts(s, ") ");
1207 }
1208
1209 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1210 {
1211 char cmd[TASK_COMM_LEN];
1212
1213 trace_find_cmdline(ent->pid, cmd);
1214
1215 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1216 int ret;
1217
1218 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1219 if (!ret)
1220 return 0;
1221 ret = blk_log_dump_pdu(s, ent);
1222 if (!ret)
1223 return 0;
1224 return trace_seq_printf(s, "[%s]\n", cmd);
1225 } else {
1226 if (t_sec(ent))
1227 return trace_seq_printf(s, "%llu + %u [%s]\n",
1228 t_sector(ent), t_sec(ent), cmd);
1229 return trace_seq_printf(s, "[%s]\n", cmd);
1230 }
1231 }
1232
1233 static int blk_log_with_error(struct trace_seq *s,
1234 const struct trace_entry *ent)
1235 {
1236 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1237 int ret;
1238
1239 ret = blk_log_dump_pdu(s, ent);
1240 if (ret)
1241 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1242 return 0;
1243 } else {
1244 if (t_sec(ent))
1245 return trace_seq_printf(s, "%llu + %u [%d]\n",
1246 t_sector(ent),
1247 t_sec(ent), t_error(ent));
1248 return trace_seq_printf(s, "%llu [%d]\n",
1249 t_sector(ent), t_error(ent));
1250 }
1251 }
1252
1253 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1254 {
1255 struct blk_io_trace_remap r = { .device_from = 0, };
1256
1257 get_pdu_remap(ent, &r);
1258 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1259 t_sector(ent), t_sec(ent),
1260 MAJOR(r.device_from), MINOR(r.device_from),
1261 (unsigned long long)r.sector_from);
1262 }
1263
1264 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1265 {
1266 char cmd[TASK_COMM_LEN];
1267
1268 trace_find_cmdline(ent->pid, cmd);
1269
1270 return trace_seq_printf(s, "[%s]\n", cmd);
1271 }
1272
1273 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1274 {
1275 char cmd[TASK_COMM_LEN];
1276
1277 trace_find_cmdline(ent->pid, cmd);
1278
1279 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1280 }
1281
1282 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1283 {
1284 char cmd[TASK_COMM_LEN];
1285
1286 trace_find_cmdline(ent->pid, cmd);
1287
1288 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1289 get_pdu_int(ent), cmd);
1290 }
1291
1292 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1293 {
1294 int ret;
1295 const struct blk_io_trace *t = te_blk_io_trace(ent);
1296
1297 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1298 if (ret)
1299 return trace_seq_putc(s, '\n');
1300 return ret;
1301 }
1302
1303 /*
1304 * struct tracer operations
1305 */
1306
1307 static void blk_tracer_print_header(struct seq_file *m)
1308 {
1309 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1310 return;
1311 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1312 "# | | | | | |\n");
1313 }
1314
1315 static void blk_tracer_start(struct trace_array *tr)
1316 {
1317 blk_tracer_enabled = true;
1318 }
1319
1320 static int blk_tracer_init(struct trace_array *tr)
1321 {
1322 blk_tr = tr;
1323 blk_tracer_start(tr);
1324 return 0;
1325 }
1326
1327 static void blk_tracer_stop(struct trace_array *tr)
1328 {
1329 blk_tracer_enabled = false;
1330 }
1331
1332 static void blk_tracer_reset(struct trace_array *tr)
1333 {
1334 blk_tracer_stop(tr);
1335 }
1336
1337 static const struct {
1338 const char *act[2];
1339 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1340 } what2act[] = {
1341 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1342 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1343 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1344 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1345 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1346 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1347 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1348 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1349 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1350 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1351 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1352 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1353 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1354 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1355 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1356 };
1357
1358 static enum print_line_t print_one_line(struct trace_iterator *iter,
1359 bool classic)
1360 {
1361 struct trace_seq *s = &iter->seq;
1362 const struct blk_io_trace *t;
1363 u16 what;
1364 int ret;
1365 bool long_act;
1366 blk_log_action_t *log_action;
1367
1368 t = te_blk_io_trace(iter->ent);
1369 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1370 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1371 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1372
1373 if (t->action == BLK_TN_MESSAGE) {
1374 ret = log_action(iter, long_act ? "message" : "m");
1375 if (ret)
1376 ret = blk_log_msg(s, iter->ent);
1377 goto out;
1378 }
1379
1380 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1381 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1382 else {
1383 ret = log_action(iter, what2act[what].act[long_act]);
1384 if (ret)
1385 ret = what2act[what].print(s, iter->ent);
1386 }
1387 out:
1388 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1389 }
1390
1391 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1392 int flags, struct trace_event *event)
1393 {
1394 return print_one_line(iter, false);
1395 }
1396
1397 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1398 {
1399 struct trace_seq *s = &iter->seq;
1400 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1401 const int offset = offsetof(struct blk_io_trace, sector);
1402 struct blk_io_trace old = {
1403 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1404 .time = iter->ts,
1405 };
1406
1407 if (!trace_seq_putmem(s, &old, offset))
1408 return 0;
1409 return trace_seq_putmem(s, &t->sector,
1410 sizeof(old) - offset + t->pdu_len);
1411 }
1412
1413 static enum print_line_t
1414 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1415 struct trace_event *event)
1416 {
1417 return blk_trace_synthesize_old_trace(iter) ?
1418 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1419 }
1420
1421 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1422 {
1423 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1424 return TRACE_TYPE_UNHANDLED;
1425
1426 return print_one_line(iter, true);
1427 }
1428
1429 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1430 {
1431 /* don't output context-info for blk_classic output */
1432 if (bit == TRACE_BLK_OPT_CLASSIC) {
1433 if (set)
1434 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1435 else
1436 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1437 }
1438 return 0;
1439 }
1440
1441 static struct tracer blk_tracer __read_mostly = {
1442 .name = "blk",
1443 .init = blk_tracer_init,
1444 .reset = blk_tracer_reset,
1445 .start = blk_tracer_start,
1446 .stop = blk_tracer_stop,
1447 .print_header = blk_tracer_print_header,
1448 .print_line = blk_tracer_print_line,
1449 .flags = &blk_tracer_flags,
1450 .set_flag = blk_tracer_set_flag,
1451 };
1452
1453 static struct trace_event_functions trace_blk_event_funcs = {
1454 .trace = blk_trace_event_print,
1455 .binary = blk_trace_event_print_binary,
1456 };
1457
1458 static struct trace_event trace_blk_event = {
1459 .type = TRACE_BLK,
1460 .funcs = &trace_blk_event_funcs,
1461 };
1462
1463 static int __init init_blk_tracer(void)
1464 {
1465 if (!register_ftrace_event(&trace_blk_event)) {
1466 pr_warning("Warning: could not register block events\n");
1467 return 1;
1468 }
1469
1470 if (register_tracer(&blk_tracer) != 0) {
1471 pr_warning("Warning: could not register the block tracer\n");
1472 unregister_ftrace_event(&trace_blk_event);
1473 return 1;
1474 }
1475
1476 return 0;
1477 }
1478
1479 device_initcall(init_blk_tracer);
1480
1481 static int blk_trace_remove_queue(struct request_queue *q)
1482 {
1483 struct blk_trace *bt;
1484
1485 bt = xchg(&q->blk_trace, NULL);
1486 if (bt == NULL)
1487 return -EINVAL;
1488
1489 if (atomic_dec_and_test(&blk_probes_ref))
1490 blk_unregister_tracepoints();
1491
1492 spin_lock_irq(&running_trace_lock);
1493 list_del(&bt->running_list);
1494 spin_unlock_irq(&running_trace_lock);
1495 blk_trace_free(bt);
1496 return 0;
1497 }
1498
1499 /*
1500 * Setup everything required to start tracing
1501 */
1502 static int blk_trace_setup_queue(struct request_queue *q,
1503 struct block_device *bdev)
1504 {
1505 struct blk_trace *old_bt, *bt = NULL;
1506 int ret = -ENOMEM;
1507
1508 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1509 if (!bt)
1510 return -ENOMEM;
1511
1512 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1513 if (!bt->msg_data)
1514 goto free_bt;
1515
1516 bt->dev = bdev->bd_dev;
1517 bt->act_mask = (u16)-1;
1518
1519 blk_trace_setup_lba(bt, bdev);
1520
1521 old_bt = xchg(&q->blk_trace, bt);
1522 if (old_bt != NULL) {
1523 (void)xchg(&q->blk_trace, old_bt);
1524 ret = -EBUSY;
1525 goto free_bt;
1526 }
1527
1528 if (atomic_inc_return(&blk_probes_ref) == 1)
1529 blk_register_tracepoints();
1530 return 0;
1531
1532 free_bt:
1533 blk_trace_free(bt);
1534 return ret;
1535 }
1536
1537 /*
1538 * sysfs interface to enable and configure tracing
1539 */
1540
1541 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1542 struct device_attribute *attr,
1543 char *buf);
1544 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1545 struct device_attribute *attr,
1546 const char *buf, size_t count);
1547 #define BLK_TRACE_DEVICE_ATTR(_name) \
1548 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1549 sysfs_blk_trace_attr_show, \
1550 sysfs_blk_trace_attr_store)
1551
1552 static BLK_TRACE_DEVICE_ATTR(enable);
1553 static BLK_TRACE_DEVICE_ATTR(act_mask);
1554 static BLK_TRACE_DEVICE_ATTR(pid);
1555 static BLK_TRACE_DEVICE_ATTR(start_lba);
1556 static BLK_TRACE_DEVICE_ATTR(end_lba);
1557
1558 static struct attribute *blk_trace_attrs[] = {
1559 &dev_attr_enable.attr,
1560 &dev_attr_act_mask.attr,
1561 &dev_attr_pid.attr,
1562 &dev_attr_start_lba.attr,
1563 &dev_attr_end_lba.attr,
1564 NULL
1565 };
1566
1567 struct attribute_group blk_trace_attr_group = {
1568 .name = "trace",
1569 .attrs = blk_trace_attrs,
1570 };
1571
1572 static const struct {
1573 int mask;
1574 const char *str;
1575 } mask_maps[] = {
1576 { BLK_TC_READ, "read" },
1577 { BLK_TC_WRITE, "write" },
1578 { BLK_TC_FLUSH, "flush" },
1579 { BLK_TC_SYNC, "sync" },
1580 { BLK_TC_QUEUE, "queue" },
1581 { BLK_TC_REQUEUE, "requeue" },
1582 { BLK_TC_ISSUE, "issue" },
1583 { BLK_TC_COMPLETE, "complete" },
1584 { BLK_TC_FS, "fs" },
1585 { BLK_TC_PC, "pc" },
1586 { BLK_TC_AHEAD, "ahead" },
1587 { BLK_TC_META, "meta" },
1588 { BLK_TC_DISCARD, "discard" },
1589 { BLK_TC_DRV_DATA, "drv_data" },
1590 { BLK_TC_FUA, "fua" },
1591 };
1592
1593 static int blk_trace_str2mask(const char *str)
1594 {
1595 int i;
1596 int mask = 0;
1597 char *buf, *s, *token;
1598
1599 buf = kstrdup(str, GFP_KERNEL);
1600 if (buf == NULL)
1601 return -ENOMEM;
1602 s = strstrip(buf);
1603
1604 while (1) {
1605 token = strsep(&s, ",");
1606 if (token == NULL)
1607 break;
1608
1609 if (*token == '\0')
1610 continue;
1611
1612 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1613 if (strcasecmp(token, mask_maps[i].str) == 0) {
1614 mask |= mask_maps[i].mask;
1615 break;
1616 }
1617 }
1618 if (i == ARRAY_SIZE(mask_maps)) {
1619 mask = -EINVAL;
1620 break;
1621 }
1622 }
1623 kfree(buf);
1624
1625 return mask;
1626 }
1627
1628 static ssize_t blk_trace_mask2str(char *buf, int mask)
1629 {
1630 int i;
1631 char *p = buf;
1632
1633 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1634 if (mask & mask_maps[i].mask) {
1635 p += sprintf(p, "%s%s",
1636 (p == buf) ? "" : ",", mask_maps[i].str);
1637 }
1638 }
1639 *p++ = '\n';
1640
1641 return p - buf;
1642 }
1643
1644 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1645 {
1646 if (bdev->bd_disk == NULL)
1647 return NULL;
1648
1649 return bdev_get_queue(bdev);
1650 }
1651
1652 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1653 struct device_attribute *attr,
1654 char *buf)
1655 {
1656 struct hd_struct *p = dev_to_part(dev);
1657 struct request_queue *q;
1658 struct block_device *bdev;
1659 ssize_t ret = -ENXIO;
1660
1661 bdev = bdget(part_devt(p));
1662 if (bdev == NULL)
1663 goto out;
1664
1665 q = blk_trace_get_queue(bdev);
1666 if (q == NULL)
1667 goto out_bdput;
1668
1669 mutex_lock(&bdev->bd_mutex);
1670
1671 if (attr == &dev_attr_enable) {
1672 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1673 goto out_unlock_bdev;
1674 }
1675
1676 if (q->blk_trace == NULL)
1677 ret = sprintf(buf, "disabled\n");
1678 else if (attr == &dev_attr_act_mask)
1679 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1680 else if (attr == &dev_attr_pid)
1681 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1682 else if (attr == &dev_attr_start_lba)
1683 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1684 else if (attr == &dev_attr_end_lba)
1685 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1686
1687 out_unlock_bdev:
1688 mutex_unlock(&bdev->bd_mutex);
1689 out_bdput:
1690 bdput(bdev);
1691 out:
1692 return ret;
1693 }
1694
1695 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1696 struct device_attribute *attr,
1697 const char *buf, size_t count)
1698 {
1699 struct block_device *bdev;
1700 struct request_queue *q;
1701 struct hd_struct *p;
1702 u64 value;
1703 ssize_t ret = -EINVAL;
1704
1705 if (count == 0)
1706 goto out;
1707
1708 if (attr == &dev_attr_act_mask) {
1709 if (sscanf(buf, "%llx", &value) != 1) {
1710 /* Assume it is a list of trace category names */
1711 ret = blk_trace_str2mask(buf);
1712 if (ret < 0)
1713 goto out;
1714 value = ret;
1715 }
1716 } else if (sscanf(buf, "%llu", &value) != 1)
1717 goto out;
1718
1719 ret = -ENXIO;
1720
1721 p = dev_to_part(dev);
1722 bdev = bdget(part_devt(p));
1723 if (bdev == NULL)
1724 goto out;
1725
1726 q = blk_trace_get_queue(bdev);
1727 if (q == NULL)
1728 goto out_bdput;
1729
1730 mutex_lock(&bdev->bd_mutex);
1731
1732 if (attr == &dev_attr_enable) {
1733 if (value)
1734 ret = blk_trace_setup_queue(q, bdev);
1735 else
1736 ret = blk_trace_remove_queue(q);
1737 goto out_unlock_bdev;
1738 }
1739
1740 ret = 0;
1741 if (q->blk_trace == NULL)
1742 ret = blk_trace_setup_queue(q, bdev);
1743
1744 if (ret == 0) {
1745 if (attr == &dev_attr_act_mask)
1746 q->blk_trace->act_mask = value;
1747 else if (attr == &dev_attr_pid)
1748 q->blk_trace->pid = value;
1749 else if (attr == &dev_attr_start_lba)
1750 q->blk_trace->start_lba = value;
1751 else if (attr == &dev_attr_end_lba)
1752 q->blk_trace->end_lba = value;
1753 }
1754
1755 out_unlock_bdev:
1756 mutex_unlock(&bdev->bd_mutex);
1757 out_bdput:
1758 bdput(bdev);
1759 out:
1760 return ret ? ret : count;
1761 }
1762
1763 int blk_trace_init_sysfs(struct device *dev)
1764 {
1765 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1766 }
1767
1768 void blk_trace_remove_sysfs(struct device *dev)
1769 {
1770 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1771 }
1772
1773 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1774
1775 #ifdef CONFIG_EVENT_TRACING
1776
1777 void blk_dump_cmd(char *buf, struct request *rq)
1778 {
1779 int i, end;
1780 int len = rq->cmd_len;
1781 unsigned char *cmd = rq->cmd;
1782
1783 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1784 buf[0] = '\0';
1785 return;
1786 }
1787
1788 for (end = len - 1; end >= 0; end--)
1789 if (cmd[end])
1790 break;
1791 end++;
1792
1793 for (i = 0; i < len; i++) {
1794 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1795 if (i == end && end != len - 1) {
1796 sprintf(buf, " ..");
1797 break;
1798 }
1799 }
1800 }
1801
1802 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1803 {
1804 int i = 0;
1805
1806 if (rw & REQ_FLUSH)
1807 rwbs[i++] = 'F';
1808
1809 if (rw & WRITE)
1810 rwbs[i++] = 'W';
1811 else if (rw & REQ_DISCARD)
1812 rwbs[i++] = 'D';
1813 else if (bytes)
1814 rwbs[i++] = 'R';
1815 else
1816 rwbs[i++] = 'N';
1817
1818 if (rw & REQ_FUA)
1819 rwbs[i++] = 'F';
1820 if (rw & REQ_RAHEAD)
1821 rwbs[i++] = 'A';
1822 if (rw & REQ_SYNC)
1823 rwbs[i++] = 'S';
1824 if (rw & REQ_META)
1825 rwbs[i++] = 'M';
1826 if (rw & REQ_SECURE)
1827 rwbs[i++] = 'E';
1828
1829 rwbs[i] = '\0';
1830 }
1831 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1832
1833 #endif /* CONFIG_EVENT_TRACING */
1834
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