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Merge tag 'trace-v4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux...
[mirror_ubuntu-artful-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(blk_tr, 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(blk_tr, 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 *bt = NULL;
441 struct dentry *dir = NULL;
442 int ret;
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 strreplace(buts->name, '/', '_');
455
456 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
457 if (!bt)
458 return -ENOMEM;
459
460 ret = -ENOMEM;
461 bt->sequence = alloc_percpu(unsigned long);
462 if (!bt->sequence)
463 goto err;
464
465 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
466 if (!bt->msg_data)
467 goto err;
468
469 ret = -ENOENT;
470
471 mutex_lock(&blk_tree_mutex);
472 if (!blk_tree_root) {
473 blk_tree_root = debugfs_create_dir("block", NULL);
474 if (!blk_tree_root) {
475 mutex_unlock(&blk_tree_mutex);
476 goto err;
477 }
478 }
479 mutex_unlock(&blk_tree_mutex);
480
481 dir = debugfs_create_dir(buts->name, blk_tree_root);
482
483 if (!dir)
484 goto err;
485
486 bt->dir = dir;
487 bt->dev = dev;
488 atomic_set(&bt->dropped, 0);
489 INIT_LIST_HEAD(&bt->running_list);
490
491 ret = -EIO;
492 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
493 &blk_dropped_fops);
494 if (!bt->dropped_file)
495 goto err;
496
497 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
498 if (!bt->msg_file)
499 goto err;
500
501 bt->rchan = relay_open("trace", dir, buts->buf_size,
502 buts->buf_nr, &blk_relay_callbacks, bt);
503 if (!bt->rchan)
504 goto err;
505
506 bt->act_mask = buts->act_mask;
507 if (!bt->act_mask)
508 bt->act_mask = (u16) -1;
509
510 blk_trace_setup_lba(bt, bdev);
511
512 /* overwrite with user settings */
513 if (buts->start_lba)
514 bt->start_lba = buts->start_lba;
515 if (buts->end_lba)
516 bt->end_lba = buts->end_lba;
517
518 bt->pid = buts->pid;
519 bt->trace_state = Blktrace_setup;
520
521 ret = -EBUSY;
522 if (cmpxchg(&q->blk_trace, NULL, bt))
523 goto err;
524
525 if (atomic_inc_return(&blk_probes_ref) == 1)
526 blk_register_tracepoints();
527
528 return 0;
529 err:
530 blk_trace_free(bt);
531 return ret;
532 }
533
534 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
535 struct block_device *bdev,
536 char __user *arg)
537 {
538 struct blk_user_trace_setup buts;
539 int ret;
540
541 ret = copy_from_user(&buts, arg, sizeof(buts));
542 if (ret)
543 return -EFAULT;
544
545 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
546 if (ret)
547 return ret;
548
549 if (copy_to_user(arg, &buts, sizeof(buts))) {
550 blk_trace_remove(q);
551 return -EFAULT;
552 }
553 return 0;
554 }
555 EXPORT_SYMBOL_GPL(blk_trace_setup);
556
557 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
558 static int compat_blk_trace_setup(struct request_queue *q, char *name,
559 dev_t dev, struct block_device *bdev,
560 char __user *arg)
561 {
562 struct blk_user_trace_setup buts;
563 struct compat_blk_user_trace_setup cbuts;
564 int ret;
565
566 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
567 return -EFAULT;
568
569 buts = (struct blk_user_trace_setup) {
570 .act_mask = cbuts.act_mask,
571 .buf_size = cbuts.buf_size,
572 .buf_nr = cbuts.buf_nr,
573 .start_lba = cbuts.start_lba,
574 .end_lba = cbuts.end_lba,
575 .pid = cbuts.pid,
576 };
577
578 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
579 if (ret)
580 return ret;
581
582 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
583 blk_trace_remove(q);
584 return -EFAULT;
585 }
586
587 return 0;
588 }
589 #endif
590
591 int blk_trace_startstop(struct request_queue *q, int start)
592 {
593 int ret;
594 struct blk_trace *bt = q->blk_trace;
595
596 if (bt == NULL)
597 return -EINVAL;
598
599 /*
600 * For starting a trace, we can transition from a setup or stopped
601 * trace. For stopping a trace, the state must be running
602 */
603 ret = -EINVAL;
604 if (start) {
605 if (bt->trace_state == Blktrace_setup ||
606 bt->trace_state == Blktrace_stopped) {
607 blktrace_seq++;
608 smp_mb();
609 bt->trace_state = Blktrace_running;
610 spin_lock_irq(&running_trace_lock);
611 list_add(&bt->running_list, &running_trace_list);
612 spin_unlock_irq(&running_trace_lock);
613
614 trace_note_time(bt);
615 ret = 0;
616 }
617 } else {
618 if (bt->trace_state == Blktrace_running) {
619 bt->trace_state = Blktrace_stopped;
620 spin_lock_irq(&running_trace_lock);
621 list_del_init(&bt->running_list);
622 spin_unlock_irq(&running_trace_lock);
623 relay_flush(bt->rchan);
624 ret = 0;
625 }
626 }
627
628 return ret;
629 }
630 EXPORT_SYMBOL_GPL(blk_trace_startstop);
631
632 /**
633 * blk_trace_ioctl: - handle the ioctls associated with tracing
634 * @bdev: the block device
635 * @cmd: the ioctl cmd
636 * @arg: the argument data, if any
637 *
638 **/
639 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
640 {
641 struct request_queue *q;
642 int ret, start = 0;
643 char b[BDEVNAME_SIZE];
644
645 q = bdev_get_queue(bdev);
646 if (!q)
647 return -ENXIO;
648
649 mutex_lock(&bdev->bd_mutex);
650
651 switch (cmd) {
652 case BLKTRACESETUP:
653 bdevname(bdev, b);
654 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
655 break;
656 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
657 case BLKTRACESETUP32:
658 bdevname(bdev, b);
659 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
660 break;
661 #endif
662 case BLKTRACESTART:
663 start = 1;
664 case BLKTRACESTOP:
665 ret = blk_trace_startstop(q, start);
666 break;
667 case BLKTRACETEARDOWN:
668 ret = blk_trace_remove(q);
669 break;
670 default:
671 ret = -ENOTTY;
672 break;
673 }
674
675 mutex_unlock(&bdev->bd_mutex);
676 return ret;
677 }
678
679 /**
680 * blk_trace_shutdown: - stop and cleanup trace structures
681 * @q: the request queue associated with the device
682 *
683 **/
684 void blk_trace_shutdown(struct request_queue *q)
685 {
686 if (q->blk_trace) {
687 blk_trace_startstop(q, 0);
688 blk_trace_remove(q);
689 }
690 }
691
692 /*
693 * blktrace probes
694 */
695
696 /**
697 * blk_add_trace_rq - Add a trace for a request oriented action
698 * @q: queue the io is for
699 * @rq: the source request
700 * @nr_bytes: number of completed bytes
701 * @what: the action
702 *
703 * Description:
704 * Records an action against a request. Will log the bio offset + size.
705 *
706 **/
707 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
708 unsigned int nr_bytes, u32 what)
709 {
710 struct blk_trace *bt = q->blk_trace;
711
712 if (likely(!bt))
713 return;
714
715 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
716 what |= BLK_TC_ACT(BLK_TC_PC);
717 __blk_add_trace(bt, 0, nr_bytes, rq->cmd_flags,
718 what, rq->errors, rq->cmd_len, rq->cmd);
719 } else {
720 what |= BLK_TC_ACT(BLK_TC_FS);
721 __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes,
722 rq->cmd_flags, what, rq->errors, 0, NULL);
723 }
724 }
725
726 static void blk_add_trace_rq_abort(void *ignore,
727 struct request_queue *q, struct request *rq)
728 {
729 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT);
730 }
731
732 static void blk_add_trace_rq_insert(void *ignore,
733 struct request_queue *q, struct request *rq)
734 {
735 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT);
736 }
737
738 static void blk_add_trace_rq_issue(void *ignore,
739 struct request_queue *q, struct request *rq)
740 {
741 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE);
742 }
743
744 static void blk_add_trace_rq_requeue(void *ignore,
745 struct request_queue *q,
746 struct request *rq)
747 {
748 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE);
749 }
750
751 static void blk_add_trace_rq_complete(void *ignore,
752 struct request_queue *q,
753 struct request *rq,
754 unsigned int nr_bytes)
755 {
756 blk_add_trace_rq(q, rq, nr_bytes, 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 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
779 bio->bi_rw, what, error, 0, NULL);
780 }
781
782 static void blk_add_trace_bio_bounce(void *ignore,
783 struct request_queue *q, struct bio *bio)
784 {
785 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
786 }
787
788 static void blk_add_trace_bio_complete(void *ignore,
789 struct request_queue *q, struct bio *bio,
790 int error)
791 {
792 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
793 }
794
795 static void blk_add_trace_bio_backmerge(void *ignore,
796 struct request_queue *q,
797 struct request *rq,
798 struct bio *bio)
799 {
800 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
801 }
802
803 static void blk_add_trace_bio_frontmerge(void *ignore,
804 struct request_queue *q,
805 struct request *rq,
806 struct bio *bio)
807 {
808 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
809 }
810
811 static void blk_add_trace_bio_queue(void *ignore,
812 struct request_queue *q, struct bio *bio)
813 {
814 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
815 }
816
817 static void blk_add_trace_getrq(void *ignore,
818 struct request_queue *q,
819 struct bio *bio, int rw)
820 {
821 if (bio)
822 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
823 else {
824 struct blk_trace *bt = q->blk_trace;
825
826 if (bt)
827 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
828 }
829 }
830
831
832 static void blk_add_trace_sleeprq(void *ignore,
833 struct request_queue *q,
834 struct bio *bio, int rw)
835 {
836 if (bio)
837 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
838 else {
839 struct blk_trace *bt = q->blk_trace;
840
841 if (bt)
842 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
843 0, 0, NULL);
844 }
845 }
846
847 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
848 {
849 struct blk_trace *bt = q->blk_trace;
850
851 if (bt)
852 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
853 }
854
855 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
856 unsigned int depth, bool explicit)
857 {
858 struct blk_trace *bt = q->blk_trace;
859
860 if (bt) {
861 __be64 rpdu = cpu_to_be64(depth);
862 u32 what;
863
864 if (explicit)
865 what = BLK_TA_UNPLUG_IO;
866 else
867 what = BLK_TA_UNPLUG_TIMER;
868
869 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
870 }
871 }
872
873 static void blk_add_trace_split(void *ignore,
874 struct request_queue *q, struct bio *bio,
875 unsigned int pdu)
876 {
877 struct blk_trace *bt = q->blk_trace;
878
879 if (bt) {
880 __be64 rpdu = cpu_to_be64(pdu);
881
882 __blk_add_trace(bt, bio->bi_iter.bi_sector,
883 bio->bi_iter.bi_size, bio->bi_rw, BLK_TA_SPLIT,
884 bio->bi_error, sizeof(rpdu), &rpdu);
885 }
886 }
887
888 /**
889 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
890 * @ignore: trace callback data parameter (not used)
891 * @q: queue the io is for
892 * @bio: the source bio
893 * @dev: target device
894 * @from: source sector
895 *
896 * Description:
897 * Device mapper or raid target sometimes need to split a bio because
898 * it spans a stripe (or similar). Add a trace for that action.
899 *
900 **/
901 static void blk_add_trace_bio_remap(void *ignore,
902 struct request_queue *q, struct bio *bio,
903 dev_t dev, sector_t from)
904 {
905 struct blk_trace *bt = q->blk_trace;
906 struct blk_io_trace_remap r;
907
908 if (likely(!bt))
909 return;
910
911 r.device_from = cpu_to_be32(dev);
912 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
913 r.sector_from = cpu_to_be64(from);
914
915 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
916 bio->bi_rw, BLK_TA_REMAP, bio->bi_error,
917 sizeof(r), &r);
918 }
919
920 /**
921 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
922 * @ignore: trace callback data parameter (not used)
923 * @q: queue the io is for
924 * @rq: the source request
925 * @dev: target device
926 * @from: source sector
927 *
928 * Description:
929 * Device mapper remaps request to other devices.
930 * Add a trace for that action.
931 *
932 **/
933 static void blk_add_trace_rq_remap(void *ignore,
934 struct request_queue *q,
935 struct request *rq, dev_t dev,
936 sector_t from)
937 {
938 struct blk_trace *bt = q->blk_trace;
939 struct blk_io_trace_remap r;
940
941 if (likely(!bt))
942 return;
943
944 r.device_from = cpu_to_be32(dev);
945 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
946 r.sector_from = cpu_to_be64(from);
947
948 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
949 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
950 sizeof(r), &r);
951 }
952
953 /**
954 * blk_add_driver_data - Add binary message with driver-specific data
955 * @q: queue the io is for
956 * @rq: io request
957 * @data: driver-specific data
958 * @len: length of driver-specific data
959 *
960 * Description:
961 * Some drivers might want to write driver-specific data per request.
962 *
963 **/
964 void blk_add_driver_data(struct request_queue *q,
965 struct request *rq,
966 void *data, size_t len)
967 {
968 struct blk_trace *bt = q->blk_trace;
969
970 if (likely(!bt))
971 return;
972
973 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
974 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
975 BLK_TA_DRV_DATA, rq->errors, len, data);
976 else
977 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
978 BLK_TA_DRV_DATA, rq->errors, len, data);
979 }
980 EXPORT_SYMBOL_GPL(blk_add_driver_data);
981
982 static void blk_register_tracepoints(void)
983 {
984 int ret;
985
986 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
987 WARN_ON(ret);
988 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
989 WARN_ON(ret);
990 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
991 WARN_ON(ret);
992 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
993 WARN_ON(ret);
994 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
995 WARN_ON(ret);
996 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
997 WARN_ON(ret);
998 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
999 WARN_ON(ret);
1000 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1001 WARN_ON(ret);
1002 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1003 WARN_ON(ret);
1004 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1005 WARN_ON(ret);
1006 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1007 WARN_ON(ret);
1008 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1009 WARN_ON(ret);
1010 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1011 WARN_ON(ret);
1012 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1013 WARN_ON(ret);
1014 ret = register_trace_block_split(blk_add_trace_split, NULL);
1015 WARN_ON(ret);
1016 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1017 WARN_ON(ret);
1018 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1019 WARN_ON(ret);
1020 }
1021
1022 static void blk_unregister_tracepoints(void)
1023 {
1024 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1025 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1026 unregister_trace_block_split(blk_add_trace_split, NULL);
1027 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1028 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1029 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1030 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1031 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1032 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1033 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1034 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1035 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1036 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1037 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1038 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1039 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1040 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1041
1042 tracepoint_synchronize_unregister();
1043 }
1044
1045 /*
1046 * struct blk_io_tracer formatting routines
1047 */
1048
1049 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1050 {
1051 int i = 0;
1052 int tc = t->action >> BLK_TC_SHIFT;
1053
1054 if (t->action == BLK_TN_MESSAGE) {
1055 rwbs[i++] = 'N';
1056 goto out;
1057 }
1058
1059 if (tc & BLK_TC_FLUSH)
1060 rwbs[i++] = 'F';
1061
1062 if (tc & BLK_TC_DISCARD)
1063 rwbs[i++] = 'D';
1064 else if (tc & BLK_TC_WRITE)
1065 rwbs[i++] = 'W';
1066 else if (t->bytes)
1067 rwbs[i++] = 'R';
1068 else
1069 rwbs[i++] = 'N';
1070
1071 if (tc & BLK_TC_FUA)
1072 rwbs[i++] = 'F';
1073 if (tc & BLK_TC_AHEAD)
1074 rwbs[i++] = 'A';
1075 if (tc & BLK_TC_SYNC)
1076 rwbs[i++] = 'S';
1077 if (tc & BLK_TC_META)
1078 rwbs[i++] = 'M';
1079 out:
1080 rwbs[i] = '\0';
1081 }
1082
1083 static inline
1084 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1085 {
1086 return (const struct blk_io_trace *)ent;
1087 }
1088
1089 static inline const void *pdu_start(const struct trace_entry *ent)
1090 {
1091 return te_blk_io_trace(ent) + 1;
1092 }
1093
1094 static inline u32 t_action(const struct trace_entry *ent)
1095 {
1096 return te_blk_io_trace(ent)->action;
1097 }
1098
1099 static inline u32 t_bytes(const struct trace_entry *ent)
1100 {
1101 return te_blk_io_trace(ent)->bytes;
1102 }
1103
1104 static inline u32 t_sec(const struct trace_entry *ent)
1105 {
1106 return te_blk_io_trace(ent)->bytes >> 9;
1107 }
1108
1109 static inline unsigned long long t_sector(const struct trace_entry *ent)
1110 {
1111 return te_blk_io_trace(ent)->sector;
1112 }
1113
1114 static inline __u16 t_error(const struct trace_entry *ent)
1115 {
1116 return te_blk_io_trace(ent)->error;
1117 }
1118
1119 static __u64 get_pdu_int(const struct trace_entry *ent)
1120 {
1121 const __u64 *val = pdu_start(ent);
1122 return be64_to_cpu(*val);
1123 }
1124
1125 static void get_pdu_remap(const struct trace_entry *ent,
1126 struct blk_io_trace_remap *r)
1127 {
1128 const struct blk_io_trace_remap *__r = pdu_start(ent);
1129 __u64 sector_from = __r->sector_from;
1130
1131 r->device_from = be32_to_cpu(__r->device_from);
1132 r->device_to = be32_to_cpu(__r->device_to);
1133 r->sector_from = be64_to_cpu(sector_from);
1134 }
1135
1136 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1137
1138 static void blk_log_action_classic(struct trace_iterator *iter, const char *act)
1139 {
1140 char rwbs[RWBS_LEN];
1141 unsigned long long ts = iter->ts;
1142 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1143 unsigned secs = (unsigned long)ts;
1144 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1145
1146 fill_rwbs(rwbs, t);
1147
1148 trace_seq_printf(&iter->seq,
1149 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1150 MAJOR(t->device), MINOR(t->device), iter->cpu,
1151 secs, nsec_rem, iter->ent->pid, act, rwbs);
1152 }
1153
1154 static void blk_log_action(struct trace_iterator *iter, const char *act)
1155 {
1156 char rwbs[RWBS_LEN];
1157 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1158
1159 fill_rwbs(rwbs, t);
1160 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1161 MAJOR(t->device), MINOR(t->device), act, rwbs);
1162 }
1163
1164 static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1165 {
1166 const unsigned char *pdu_buf;
1167 int pdu_len;
1168 int i, end;
1169
1170 pdu_buf = pdu_start(ent);
1171 pdu_len = te_blk_io_trace(ent)->pdu_len;
1172
1173 if (!pdu_len)
1174 return;
1175
1176 /* find the last zero that needs to be printed */
1177 for (end = pdu_len - 1; end >= 0; end--)
1178 if (pdu_buf[end])
1179 break;
1180 end++;
1181
1182 trace_seq_putc(s, '(');
1183
1184 for (i = 0; i < pdu_len; i++) {
1185
1186 trace_seq_printf(s, "%s%02x",
1187 i == 0 ? "" : " ", pdu_buf[i]);
1188
1189 /*
1190 * stop when the rest is just zeroes and indicate so
1191 * with a ".." appended
1192 */
1193 if (i == end && end != pdu_len - 1) {
1194 trace_seq_puts(s, " ..) ");
1195 return;
1196 }
1197 }
1198
1199 trace_seq_puts(s, ") ");
1200 }
1201
1202 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1203 {
1204 char cmd[TASK_COMM_LEN];
1205
1206 trace_find_cmdline(ent->pid, cmd);
1207
1208 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1209 trace_seq_printf(s, "%u ", t_bytes(ent));
1210 blk_log_dump_pdu(s, ent);
1211 trace_seq_printf(s, "[%s]\n", cmd);
1212 } else {
1213 if (t_sec(ent))
1214 trace_seq_printf(s, "%llu + %u [%s]\n",
1215 t_sector(ent), t_sec(ent), cmd);
1216 else
1217 trace_seq_printf(s, "[%s]\n", cmd);
1218 }
1219 }
1220
1221 static void blk_log_with_error(struct trace_seq *s,
1222 const struct trace_entry *ent)
1223 {
1224 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1225 blk_log_dump_pdu(s, ent);
1226 trace_seq_printf(s, "[%d]\n", t_error(ent));
1227 } else {
1228 if (t_sec(ent))
1229 trace_seq_printf(s, "%llu + %u [%d]\n",
1230 t_sector(ent),
1231 t_sec(ent), t_error(ent));
1232 else
1233 trace_seq_printf(s, "%llu [%d]\n",
1234 t_sector(ent), t_error(ent));
1235 }
1236 }
1237
1238 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1239 {
1240 struct blk_io_trace_remap r = { .device_from = 0, };
1241
1242 get_pdu_remap(ent, &r);
1243 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1244 t_sector(ent), t_sec(ent),
1245 MAJOR(r.device_from), MINOR(r.device_from),
1246 (unsigned long long)r.sector_from);
1247 }
1248
1249 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1250 {
1251 char cmd[TASK_COMM_LEN];
1252
1253 trace_find_cmdline(ent->pid, cmd);
1254
1255 trace_seq_printf(s, "[%s]\n", cmd);
1256 }
1257
1258 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1259 {
1260 char cmd[TASK_COMM_LEN];
1261
1262 trace_find_cmdline(ent->pid, cmd);
1263
1264 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1265 }
1266
1267 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1268 {
1269 char cmd[TASK_COMM_LEN];
1270
1271 trace_find_cmdline(ent->pid, cmd);
1272
1273 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1274 get_pdu_int(ent), cmd);
1275 }
1276
1277 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1278 {
1279 const struct blk_io_trace *t = te_blk_io_trace(ent);
1280
1281 trace_seq_putmem(s, t + 1, t->pdu_len);
1282 trace_seq_putc(s, '\n');
1283 }
1284
1285 /*
1286 * struct tracer operations
1287 */
1288
1289 static void blk_tracer_print_header(struct seq_file *m)
1290 {
1291 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1292 return;
1293 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1294 "# | | | | | |\n");
1295 }
1296
1297 static void blk_tracer_start(struct trace_array *tr)
1298 {
1299 blk_tracer_enabled = true;
1300 }
1301
1302 static int blk_tracer_init(struct trace_array *tr)
1303 {
1304 blk_tr = tr;
1305 blk_tracer_start(tr);
1306 return 0;
1307 }
1308
1309 static void blk_tracer_stop(struct trace_array *tr)
1310 {
1311 blk_tracer_enabled = false;
1312 }
1313
1314 static void blk_tracer_reset(struct trace_array *tr)
1315 {
1316 blk_tracer_stop(tr);
1317 }
1318
1319 static const struct {
1320 const char *act[2];
1321 void (*print)(struct trace_seq *s, const struct trace_entry *ent);
1322 } what2act[] = {
1323 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1324 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1325 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1326 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1327 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1328 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1329 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1330 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1331 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1332 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1333 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1334 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1335 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1336 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1337 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1338 };
1339
1340 static enum print_line_t print_one_line(struct trace_iterator *iter,
1341 bool classic)
1342 {
1343 struct trace_array *tr = iter->tr;
1344 struct trace_seq *s = &iter->seq;
1345 const struct blk_io_trace *t;
1346 u16 what;
1347 bool long_act;
1348 blk_log_action_t *log_action;
1349
1350 t = te_blk_io_trace(iter->ent);
1351 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1352 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1353 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1354
1355 if (t->action == BLK_TN_MESSAGE) {
1356 log_action(iter, long_act ? "message" : "m");
1357 blk_log_msg(s, iter->ent);
1358 }
1359
1360 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1361 trace_seq_printf(s, "Unknown action %x\n", what);
1362 else {
1363 log_action(iter, what2act[what].act[long_act]);
1364 what2act[what].print(s, iter->ent);
1365 }
1366
1367 return trace_handle_return(s);
1368 }
1369
1370 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1371 int flags, struct trace_event *event)
1372 {
1373 return print_one_line(iter, false);
1374 }
1375
1376 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1377 {
1378 struct trace_seq *s = &iter->seq;
1379 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1380 const int offset = offsetof(struct blk_io_trace, sector);
1381 struct blk_io_trace old = {
1382 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1383 .time = iter->ts,
1384 };
1385
1386 trace_seq_putmem(s, &old, offset);
1387 trace_seq_putmem(s, &t->sector,
1388 sizeof(old) - offset + t->pdu_len);
1389 }
1390
1391 static enum print_line_t
1392 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1393 struct trace_event *event)
1394 {
1395 blk_trace_synthesize_old_trace(iter);
1396
1397 return trace_handle_return(&iter->seq);
1398 }
1399
1400 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1401 {
1402 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1403 return TRACE_TYPE_UNHANDLED;
1404
1405 return print_one_line(iter, true);
1406 }
1407
1408 static int
1409 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1410 {
1411 /* don't output context-info for blk_classic output */
1412 if (bit == TRACE_BLK_OPT_CLASSIC) {
1413 if (set)
1414 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1415 else
1416 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1417 }
1418 return 0;
1419 }
1420
1421 static struct tracer blk_tracer __read_mostly = {
1422 .name = "blk",
1423 .init = blk_tracer_init,
1424 .reset = blk_tracer_reset,
1425 .start = blk_tracer_start,
1426 .stop = blk_tracer_stop,
1427 .print_header = blk_tracer_print_header,
1428 .print_line = blk_tracer_print_line,
1429 .flags = &blk_tracer_flags,
1430 .set_flag = blk_tracer_set_flag,
1431 };
1432
1433 static struct trace_event_functions trace_blk_event_funcs = {
1434 .trace = blk_trace_event_print,
1435 .binary = blk_trace_event_print_binary,
1436 };
1437
1438 static struct trace_event trace_blk_event = {
1439 .type = TRACE_BLK,
1440 .funcs = &trace_blk_event_funcs,
1441 };
1442
1443 static int __init init_blk_tracer(void)
1444 {
1445 if (!register_trace_event(&trace_blk_event)) {
1446 pr_warning("Warning: could not register block events\n");
1447 return 1;
1448 }
1449
1450 if (register_tracer(&blk_tracer) != 0) {
1451 pr_warning("Warning: could not register the block tracer\n");
1452 unregister_trace_event(&trace_blk_event);
1453 return 1;
1454 }
1455
1456 return 0;
1457 }
1458
1459 device_initcall(init_blk_tracer);
1460
1461 static int blk_trace_remove_queue(struct request_queue *q)
1462 {
1463 struct blk_trace *bt;
1464
1465 bt = xchg(&q->blk_trace, NULL);
1466 if (bt == NULL)
1467 return -EINVAL;
1468
1469 if (atomic_dec_and_test(&blk_probes_ref))
1470 blk_unregister_tracepoints();
1471
1472 blk_trace_free(bt);
1473 return 0;
1474 }
1475
1476 /*
1477 * Setup everything required to start tracing
1478 */
1479 static int blk_trace_setup_queue(struct request_queue *q,
1480 struct block_device *bdev)
1481 {
1482 struct blk_trace *bt = NULL;
1483 int ret = -ENOMEM;
1484
1485 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1486 if (!bt)
1487 return -ENOMEM;
1488
1489 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1490 if (!bt->msg_data)
1491 goto free_bt;
1492
1493 bt->dev = bdev->bd_dev;
1494 bt->act_mask = (u16)-1;
1495
1496 blk_trace_setup_lba(bt, bdev);
1497
1498 ret = -EBUSY;
1499 if (cmpxchg(&q->blk_trace, NULL, bt))
1500 goto free_bt;
1501
1502 if (atomic_inc_return(&blk_probes_ref) == 1)
1503 blk_register_tracepoints();
1504 return 0;
1505
1506 free_bt:
1507 blk_trace_free(bt);
1508 return ret;
1509 }
1510
1511 /*
1512 * sysfs interface to enable and configure tracing
1513 */
1514
1515 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1516 struct device_attribute *attr,
1517 char *buf);
1518 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1519 struct device_attribute *attr,
1520 const char *buf, size_t count);
1521 #define BLK_TRACE_DEVICE_ATTR(_name) \
1522 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1523 sysfs_blk_trace_attr_show, \
1524 sysfs_blk_trace_attr_store)
1525
1526 static BLK_TRACE_DEVICE_ATTR(enable);
1527 static BLK_TRACE_DEVICE_ATTR(act_mask);
1528 static BLK_TRACE_DEVICE_ATTR(pid);
1529 static BLK_TRACE_DEVICE_ATTR(start_lba);
1530 static BLK_TRACE_DEVICE_ATTR(end_lba);
1531
1532 static struct attribute *blk_trace_attrs[] = {
1533 &dev_attr_enable.attr,
1534 &dev_attr_act_mask.attr,
1535 &dev_attr_pid.attr,
1536 &dev_attr_start_lba.attr,
1537 &dev_attr_end_lba.attr,
1538 NULL
1539 };
1540
1541 struct attribute_group blk_trace_attr_group = {
1542 .name = "trace",
1543 .attrs = blk_trace_attrs,
1544 };
1545
1546 static const struct {
1547 int mask;
1548 const char *str;
1549 } mask_maps[] = {
1550 { BLK_TC_READ, "read" },
1551 { BLK_TC_WRITE, "write" },
1552 { BLK_TC_FLUSH, "flush" },
1553 { BLK_TC_SYNC, "sync" },
1554 { BLK_TC_QUEUE, "queue" },
1555 { BLK_TC_REQUEUE, "requeue" },
1556 { BLK_TC_ISSUE, "issue" },
1557 { BLK_TC_COMPLETE, "complete" },
1558 { BLK_TC_FS, "fs" },
1559 { BLK_TC_PC, "pc" },
1560 { BLK_TC_AHEAD, "ahead" },
1561 { BLK_TC_META, "meta" },
1562 { BLK_TC_DISCARD, "discard" },
1563 { BLK_TC_DRV_DATA, "drv_data" },
1564 { BLK_TC_FUA, "fua" },
1565 };
1566
1567 static int blk_trace_str2mask(const char *str)
1568 {
1569 int i;
1570 int mask = 0;
1571 char *buf, *s, *token;
1572
1573 buf = kstrdup(str, GFP_KERNEL);
1574 if (buf == NULL)
1575 return -ENOMEM;
1576 s = strstrip(buf);
1577
1578 while (1) {
1579 token = strsep(&s, ",");
1580 if (token == NULL)
1581 break;
1582
1583 if (*token == '\0')
1584 continue;
1585
1586 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1587 if (strcasecmp(token, mask_maps[i].str) == 0) {
1588 mask |= mask_maps[i].mask;
1589 break;
1590 }
1591 }
1592 if (i == ARRAY_SIZE(mask_maps)) {
1593 mask = -EINVAL;
1594 break;
1595 }
1596 }
1597 kfree(buf);
1598
1599 return mask;
1600 }
1601
1602 static ssize_t blk_trace_mask2str(char *buf, int mask)
1603 {
1604 int i;
1605 char *p = buf;
1606
1607 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1608 if (mask & mask_maps[i].mask) {
1609 p += sprintf(p, "%s%s",
1610 (p == buf) ? "" : ",", mask_maps[i].str);
1611 }
1612 }
1613 *p++ = '\n';
1614
1615 return p - buf;
1616 }
1617
1618 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1619 {
1620 if (bdev->bd_disk == NULL)
1621 return NULL;
1622
1623 return bdev_get_queue(bdev);
1624 }
1625
1626 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1627 struct device_attribute *attr,
1628 char *buf)
1629 {
1630 struct hd_struct *p = dev_to_part(dev);
1631 struct request_queue *q;
1632 struct block_device *bdev;
1633 ssize_t ret = -ENXIO;
1634
1635 bdev = bdget(part_devt(p));
1636 if (bdev == NULL)
1637 goto out;
1638
1639 q = blk_trace_get_queue(bdev);
1640 if (q == NULL)
1641 goto out_bdput;
1642
1643 mutex_lock(&bdev->bd_mutex);
1644
1645 if (attr == &dev_attr_enable) {
1646 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1647 goto out_unlock_bdev;
1648 }
1649
1650 if (q->blk_trace == NULL)
1651 ret = sprintf(buf, "disabled\n");
1652 else if (attr == &dev_attr_act_mask)
1653 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1654 else if (attr == &dev_attr_pid)
1655 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1656 else if (attr == &dev_attr_start_lba)
1657 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1658 else if (attr == &dev_attr_end_lba)
1659 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1660
1661 out_unlock_bdev:
1662 mutex_unlock(&bdev->bd_mutex);
1663 out_bdput:
1664 bdput(bdev);
1665 out:
1666 return ret;
1667 }
1668
1669 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1670 struct device_attribute *attr,
1671 const char *buf, size_t count)
1672 {
1673 struct block_device *bdev;
1674 struct request_queue *q;
1675 struct hd_struct *p;
1676 u64 value;
1677 ssize_t ret = -EINVAL;
1678
1679 if (count == 0)
1680 goto out;
1681
1682 if (attr == &dev_attr_act_mask) {
1683 if (sscanf(buf, "%llx", &value) != 1) {
1684 /* Assume it is a list of trace category names */
1685 ret = blk_trace_str2mask(buf);
1686 if (ret < 0)
1687 goto out;
1688 value = ret;
1689 }
1690 } else if (sscanf(buf, "%llu", &value) != 1)
1691 goto out;
1692
1693 ret = -ENXIO;
1694
1695 p = dev_to_part(dev);
1696 bdev = bdget(part_devt(p));
1697 if (bdev == NULL)
1698 goto out;
1699
1700 q = blk_trace_get_queue(bdev);
1701 if (q == NULL)
1702 goto out_bdput;
1703
1704 mutex_lock(&bdev->bd_mutex);
1705
1706 if (attr == &dev_attr_enable) {
1707 if (value)
1708 ret = blk_trace_setup_queue(q, bdev);
1709 else
1710 ret = blk_trace_remove_queue(q);
1711 goto out_unlock_bdev;
1712 }
1713
1714 ret = 0;
1715 if (q->blk_trace == NULL)
1716 ret = blk_trace_setup_queue(q, bdev);
1717
1718 if (ret == 0) {
1719 if (attr == &dev_attr_act_mask)
1720 q->blk_trace->act_mask = value;
1721 else if (attr == &dev_attr_pid)
1722 q->blk_trace->pid = value;
1723 else if (attr == &dev_attr_start_lba)
1724 q->blk_trace->start_lba = value;
1725 else if (attr == &dev_attr_end_lba)
1726 q->blk_trace->end_lba = value;
1727 }
1728
1729 out_unlock_bdev:
1730 mutex_unlock(&bdev->bd_mutex);
1731 out_bdput:
1732 bdput(bdev);
1733 out:
1734 return ret ? ret : count;
1735 }
1736
1737 int blk_trace_init_sysfs(struct device *dev)
1738 {
1739 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1740 }
1741
1742 void blk_trace_remove_sysfs(struct device *dev)
1743 {
1744 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1745 }
1746
1747 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1748
1749 #ifdef CONFIG_EVENT_TRACING
1750
1751 void blk_dump_cmd(char *buf, struct request *rq)
1752 {
1753 int i, end;
1754 int len = rq->cmd_len;
1755 unsigned char *cmd = rq->cmd;
1756
1757 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1758 buf[0] = '\0';
1759 return;
1760 }
1761
1762 for (end = len - 1; end >= 0; end--)
1763 if (cmd[end])
1764 break;
1765 end++;
1766
1767 for (i = 0; i < len; i++) {
1768 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1769 if (i == end && end != len - 1) {
1770 sprintf(buf, " ..");
1771 break;
1772 }
1773 }
1774 }
1775
1776 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1777 {
1778 int i = 0;
1779
1780 if (rw & REQ_FLUSH)
1781 rwbs[i++] = 'F';
1782
1783 if (rw & WRITE)
1784 rwbs[i++] = 'W';
1785 else if (rw & REQ_DISCARD)
1786 rwbs[i++] = 'D';
1787 else if (bytes)
1788 rwbs[i++] = 'R';
1789 else
1790 rwbs[i++] = 'N';
1791
1792 if (rw & REQ_FUA)
1793 rwbs[i++] = 'F';
1794 if (rw & REQ_RAHEAD)
1795 rwbs[i++] = 'A';
1796 if (rw & REQ_SYNC)
1797 rwbs[i++] = 'S';
1798 if (rw & REQ_META)
1799 rwbs[i++] = 'M';
1800 if (rw & REQ_SECURE)
1801 rwbs[i++] = 'E';
1802
1803 rwbs[i] = '\0';
1804 }
1805 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1806
1807 #endif /* CONFIG_EVENT_TRACING */
1808
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