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Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
[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 = memdup_user_nul(buffer, count);
353 if (IS_ERR(msg))
354 return PTR_ERR(msg);
355
356 bt = filp->private_data;
357 __trace_note_message(bt, "%s", msg);
358 kfree(msg);
359
360 return count;
361 }
362
363 static const struct file_operations blk_msg_fops = {
364 .owner = THIS_MODULE,
365 .open = simple_open,
366 .write = blk_msg_write,
367 .llseek = noop_llseek,
368 };
369
370 /*
371 * Keep track of how many times we encountered a full subbuffer, to aid
372 * the user space app in telling how many lost events there were.
373 */
374 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
375 void *prev_subbuf, size_t prev_padding)
376 {
377 struct blk_trace *bt;
378
379 if (!relay_buf_full(buf))
380 return 1;
381
382 bt = buf->chan->private_data;
383 atomic_inc(&bt->dropped);
384 return 0;
385 }
386
387 static int blk_remove_buf_file_callback(struct dentry *dentry)
388 {
389 debugfs_remove(dentry);
390
391 return 0;
392 }
393
394 static struct dentry *blk_create_buf_file_callback(const char *filename,
395 struct dentry *parent,
396 umode_t mode,
397 struct rchan_buf *buf,
398 int *is_global)
399 {
400 return debugfs_create_file(filename, mode, parent, buf,
401 &relay_file_operations);
402 }
403
404 static struct rchan_callbacks blk_relay_callbacks = {
405 .subbuf_start = blk_subbuf_start_callback,
406 .create_buf_file = blk_create_buf_file_callback,
407 .remove_buf_file = blk_remove_buf_file_callback,
408 };
409
410 static void blk_trace_setup_lba(struct blk_trace *bt,
411 struct block_device *bdev)
412 {
413 struct hd_struct *part = NULL;
414
415 if (bdev)
416 part = bdev->bd_part;
417
418 if (part) {
419 bt->start_lba = part->start_sect;
420 bt->end_lba = part->start_sect + part->nr_sects;
421 } else {
422 bt->start_lba = 0;
423 bt->end_lba = -1ULL;
424 }
425 }
426
427 /*
428 * Setup everything required to start tracing
429 */
430 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
431 struct block_device *bdev,
432 struct blk_user_trace_setup *buts)
433 {
434 struct blk_trace *bt = NULL;
435 struct dentry *dir = NULL;
436 int ret;
437
438 if (!buts->buf_size || !buts->buf_nr)
439 return -EINVAL;
440
441 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
442 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
443
444 /*
445 * some device names have larger paths - convert the slashes
446 * to underscores for this to work as expected
447 */
448 strreplace(buts->name, '/', '_');
449
450 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
451 if (!bt)
452 return -ENOMEM;
453
454 ret = -ENOMEM;
455 bt->sequence = alloc_percpu(unsigned long);
456 if (!bt->sequence)
457 goto err;
458
459 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
460 if (!bt->msg_data)
461 goto err;
462
463 ret = -ENOENT;
464
465 mutex_lock(&blk_tree_mutex);
466 if (!blk_tree_root) {
467 blk_tree_root = debugfs_create_dir("block", NULL);
468 if (!blk_tree_root) {
469 mutex_unlock(&blk_tree_mutex);
470 goto err;
471 }
472 }
473 mutex_unlock(&blk_tree_mutex);
474
475 dir = debugfs_create_dir(buts->name, blk_tree_root);
476
477 if (!dir)
478 goto err;
479
480 bt->dir = dir;
481 bt->dev = dev;
482 atomic_set(&bt->dropped, 0);
483 INIT_LIST_HEAD(&bt->running_list);
484
485 ret = -EIO;
486 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
487 &blk_dropped_fops);
488 if (!bt->dropped_file)
489 goto err;
490
491 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
492 if (!bt->msg_file)
493 goto err;
494
495 bt->rchan = relay_open("trace", dir, buts->buf_size,
496 buts->buf_nr, &blk_relay_callbacks, bt);
497 if (!bt->rchan)
498 goto err;
499
500 bt->act_mask = buts->act_mask;
501 if (!bt->act_mask)
502 bt->act_mask = (u16) -1;
503
504 blk_trace_setup_lba(bt, bdev);
505
506 /* overwrite with user settings */
507 if (buts->start_lba)
508 bt->start_lba = buts->start_lba;
509 if (buts->end_lba)
510 bt->end_lba = buts->end_lba;
511
512 bt->pid = buts->pid;
513 bt->trace_state = Blktrace_setup;
514
515 ret = -EBUSY;
516 if (cmpxchg(&q->blk_trace, NULL, bt))
517 goto err;
518
519 if (atomic_inc_return(&blk_probes_ref) == 1)
520 blk_register_tracepoints();
521
522 return 0;
523 err:
524 blk_trace_free(bt);
525 return ret;
526 }
527
528 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
529 struct block_device *bdev,
530 char __user *arg)
531 {
532 struct blk_user_trace_setup buts;
533 int ret;
534
535 ret = copy_from_user(&buts, arg, sizeof(buts));
536 if (ret)
537 return -EFAULT;
538
539 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
540 if (ret)
541 return ret;
542
543 if (copy_to_user(arg, &buts, sizeof(buts))) {
544 blk_trace_remove(q);
545 return -EFAULT;
546 }
547 return 0;
548 }
549 EXPORT_SYMBOL_GPL(blk_trace_setup);
550
551 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
552 static int compat_blk_trace_setup(struct request_queue *q, char *name,
553 dev_t dev, struct block_device *bdev,
554 char __user *arg)
555 {
556 struct blk_user_trace_setup buts;
557 struct compat_blk_user_trace_setup cbuts;
558 int ret;
559
560 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
561 return -EFAULT;
562
563 buts = (struct blk_user_trace_setup) {
564 .act_mask = cbuts.act_mask,
565 .buf_size = cbuts.buf_size,
566 .buf_nr = cbuts.buf_nr,
567 .start_lba = cbuts.start_lba,
568 .end_lba = cbuts.end_lba,
569 .pid = cbuts.pid,
570 };
571
572 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
573 if (ret)
574 return ret;
575
576 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
577 blk_trace_remove(q);
578 return -EFAULT;
579 }
580
581 return 0;
582 }
583 #endif
584
585 int blk_trace_startstop(struct request_queue *q, int start)
586 {
587 int ret;
588 struct blk_trace *bt = q->blk_trace;
589
590 if (bt == NULL)
591 return -EINVAL;
592
593 /*
594 * For starting a trace, we can transition from a setup or stopped
595 * trace. For stopping a trace, the state must be running
596 */
597 ret = -EINVAL;
598 if (start) {
599 if (bt->trace_state == Blktrace_setup ||
600 bt->trace_state == Blktrace_stopped) {
601 blktrace_seq++;
602 smp_mb();
603 bt->trace_state = Blktrace_running;
604 spin_lock_irq(&running_trace_lock);
605 list_add(&bt->running_list, &running_trace_list);
606 spin_unlock_irq(&running_trace_lock);
607
608 trace_note_time(bt);
609 ret = 0;
610 }
611 } else {
612 if (bt->trace_state == Blktrace_running) {
613 bt->trace_state = Blktrace_stopped;
614 spin_lock_irq(&running_trace_lock);
615 list_del_init(&bt->running_list);
616 spin_unlock_irq(&running_trace_lock);
617 relay_flush(bt->rchan);
618 ret = 0;
619 }
620 }
621
622 return ret;
623 }
624 EXPORT_SYMBOL_GPL(blk_trace_startstop);
625
626 /**
627 * blk_trace_ioctl: - handle the ioctls associated with tracing
628 * @bdev: the block device
629 * @cmd: the ioctl cmd
630 * @arg: the argument data, if any
631 *
632 **/
633 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
634 {
635 struct request_queue *q;
636 int ret, start = 0;
637 char b[BDEVNAME_SIZE];
638
639 q = bdev_get_queue(bdev);
640 if (!q)
641 return -ENXIO;
642
643 mutex_lock(&bdev->bd_mutex);
644
645 switch (cmd) {
646 case BLKTRACESETUP:
647 bdevname(bdev, b);
648 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
649 break;
650 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
651 case BLKTRACESETUP32:
652 bdevname(bdev, b);
653 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
654 break;
655 #endif
656 case BLKTRACESTART:
657 start = 1;
658 case BLKTRACESTOP:
659 ret = blk_trace_startstop(q, start);
660 break;
661 case BLKTRACETEARDOWN:
662 ret = blk_trace_remove(q);
663 break;
664 default:
665 ret = -ENOTTY;
666 break;
667 }
668
669 mutex_unlock(&bdev->bd_mutex);
670 return ret;
671 }
672
673 /**
674 * blk_trace_shutdown: - stop and cleanup trace structures
675 * @q: the request queue associated with the device
676 *
677 **/
678 void blk_trace_shutdown(struct request_queue *q)
679 {
680 if (q->blk_trace) {
681 blk_trace_startstop(q, 0);
682 blk_trace_remove(q);
683 }
684 }
685
686 /*
687 * blktrace probes
688 */
689
690 /**
691 * blk_add_trace_rq - Add a trace for a request oriented action
692 * @q: queue the io is for
693 * @rq: the source request
694 * @nr_bytes: number of completed bytes
695 * @what: the action
696 *
697 * Description:
698 * Records an action against a request. Will log the bio offset + size.
699 *
700 **/
701 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
702 unsigned int nr_bytes, u32 what)
703 {
704 struct blk_trace *bt = q->blk_trace;
705
706 if (likely(!bt))
707 return;
708
709 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
710 what |= BLK_TC_ACT(BLK_TC_PC);
711 __blk_add_trace(bt, 0, nr_bytes, rq->cmd_flags,
712 what, rq->errors, rq->cmd_len, rq->cmd);
713 } else {
714 what |= BLK_TC_ACT(BLK_TC_FS);
715 __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes,
716 rq->cmd_flags, what, rq->errors, 0, NULL);
717 }
718 }
719
720 static void blk_add_trace_rq_abort(void *ignore,
721 struct request_queue *q, struct request *rq)
722 {
723 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT);
724 }
725
726 static void blk_add_trace_rq_insert(void *ignore,
727 struct request_queue *q, struct request *rq)
728 {
729 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT);
730 }
731
732 static void blk_add_trace_rq_issue(void *ignore,
733 struct request_queue *q, struct request *rq)
734 {
735 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE);
736 }
737
738 static void blk_add_trace_rq_requeue(void *ignore,
739 struct request_queue *q,
740 struct request *rq)
741 {
742 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE);
743 }
744
745 static void blk_add_trace_rq_complete(void *ignore,
746 struct request_queue *q,
747 struct request *rq,
748 unsigned int nr_bytes)
749 {
750 blk_add_trace_rq(q, rq, nr_bytes, BLK_TA_COMPLETE);
751 }
752
753 /**
754 * blk_add_trace_bio - Add a trace for a bio oriented action
755 * @q: queue the io is for
756 * @bio: the source bio
757 * @what: the action
758 * @error: error, if any
759 *
760 * Description:
761 * Records an action against a bio. Will log the bio offset + size.
762 *
763 **/
764 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
765 u32 what, int error)
766 {
767 struct blk_trace *bt = q->blk_trace;
768
769 if (likely(!bt))
770 return;
771
772 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
773 bio->bi_rw, what, error, 0, NULL);
774 }
775
776 static void blk_add_trace_bio_bounce(void *ignore,
777 struct request_queue *q, struct bio *bio)
778 {
779 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
780 }
781
782 static void blk_add_trace_bio_complete(void *ignore,
783 struct request_queue *q, struct bio *bio,
784 int error)
785 {
786 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
787 }
788
789 static void blk_add_trace_bio_backmerge(void *ignore,
790 struct request_queue *q,
791 struct request *rq,
792 struct bio *bio)
793 {
794 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
795 }
796
797 static void blk_add_trace_bio_frontmerge(void *ignore,
798 struct request_queue *q,
799 struct request *rq,
800 struct bio *bio)
801 {
802 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
803 }
804
805 static void blk_add_trace_bio_queue(void *ignore,
806 struct request_queue *q, struct bio *bio)
807 {
808 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
809 }
810
811 static void blk_add_trace_getrq(void *ignore,
812 struct request_queue *q,
813 struct bio *bio, int rw)
814 {
815 if (bio)
816 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
817 else {
818 struct blk_trace *bt = q->blk_trace;
819
820 if (bt)
821 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
822 }
823 }
824
825
826 static void blk_add_trace_sleeprq(void *ignore,
827 struct request_queue *q,
828 struct bio *bio, int rw)
829 {
830 if (bio)
831 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
832 else {
833 struct blk_trace *bt = q->blk_trace;
834
835 if (bt)
836 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
837 0, 0, NULL);
838 }
839 }
840
841 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
842 {
843 struct blk_trace *bt = q->blk_trace;
844
845 if (bt)
846 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
847 }
848
849 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
850 unsigned int depth, bool explicit)
851 {
852 struct blk_trace *bt = q->blk_trace;
853
854 if (bt) {
855 __be64 rpdu = cpu_to_be64(depth);
856 u32 what;
857
858 if (explicit)
859 what = BLK_TA_UNPLUG_IO;
860 else
861 what = BLK_TA_UNPLUG_TIMER;
862
863 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
864 }
865 }
866
867 static void blk_add_trace_split(void *ignore,
868 struct request_queue *q, struct bio *bio,
869 unsigned int pdu)
870 {
871 struct blk_trace *bt = q->blk_trace;
872
873 if (bt) {
874 __be64 rpdu = cpu_to_be64(pdu);
875
876 __blk_add_trace(bt, bio->bi_iter.bi_sector,
877 bio->bi_iter.bi_size, bio->bi_rw, BLK_TA_SPLIT,
878 bio->bi_error, sizeof(rpdu), &rpdu);
879 }
880 }
881
882 /**
883 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
884 * @ignore: trace callback data parameter (not used)
885 * @q: queue the io is for
886 * @bio: the source bio
887 * @dev: target device
888 * @from: source sector
889 *
890 * Description:
891 * Device mapper or raid target sometimes need to split a bio because
892 * it spans a stripe (or similar). Add a trace for that action.
893 *
894 **/
895 static void blk_add_trace_bio_remap(void *ignore,
896 struct request_queue *q, struct bio *bio,
897 dev_t dev, sector_t from)
898 {
899 struct blk_trace *bt = q->blk_trace;
900 struct blk_io_trace_remap r;
901
902 if (likely(!bt))
903 return;
904
905 r.device_from = cpu_to_be32(dev);
906 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
907 r.sector_from = cpu_to_be64(from);
908
909 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
910 bio->bi_rw, BLK_TA_REMAP, bio->bi_error,
911 sizeof(r), &r);
912 }
913
914 /**
915 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
916 * @ignore: trace callback data parameter (not used)
917 * @q: queue the io is for
918 * @rq: the source request
919 * @dev: target device
920 * @from: source sector
921 *
922 * Description:
923 * Device mapper remaps request to other devices.
924 * Add a trace for that action.
925 *
926 **/
927 static void blk_add_trace_rq_remap(void *ignore,
928 struct request_queue *q,
929 struct request *rq, dev_t dev,
930 sector_t from)
931 {
932 struct blk_trace *bt = q->blk_trace;
933 struct blk_io_trace_remap r;
934
935 if (likely(!bt))
936 return;
937
938 r.device_from = cpu_to_be32(dev);
939 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
940 r.sector_from = cpu_to_be64(from);
941
942 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
943 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
944 sizeof(r), &r);
945 }
946
947 /**
948 * blk_add_driver_data - Add binary message with driver-specific data
949 * @q: queue the io is for
950 * @rq: io request
951 * @data: driver-specific data
952 * @len: length of driver-specific data
953 *
954 * Description:
955 * Some drivers might want to write driver-specific data per request.
956 *
957 **/
958 void blk_add_driver_data(struct request_queue *q,
959 struct request *rq,
960 void *data, size_t len)
961 {
962 struct blk_trace *bt = q->blk_trace;
963
964 if (likely(!bt))
965 return;
966
967 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
968 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
969 BLK_TA_DRV_DATA, rq->errors, len, data);
970 else
971 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
972 BLK_TA_DRV_DATA, rq->errors, len, data);
973 }
974 EXPORT_SYMBOL_GPL(blk_add_driver_data);
975
976 static void blk_register_tracepoints(void)
977 {
978 int ret;
979
980 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
981 WARN_ON(ret);
982 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
983 WARN_ON(ret);
984 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
985 WARN_ON(ret);
986 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
987 WARN_ON(ret);
988 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
989 WARN_ON(ret);
990 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
991 WARN_ON(ret);
992 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
993 WARN_ON(ret);
994 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
995 WARN_ON(ret);
996 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
997 WARN_ON(ret);
998 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
999 WARN_ON(ret);
1000 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1001 WARN_ON(ret);
1002 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1003 WARN_ON(ret);
1004 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1005 WARN_ON(ret);
1006 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1007 WARN_ON(ret);
1008 ret = register_trace_block_split(blk_add_trace_split, NULL);
1009 WARN_ON(ret);
1010 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1011 WARN_ON(ret);
1012 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1013 WARN_ON(ret);
1014 }
1015
1016 static void blk_unregister_tracepoints(void)
1017 {
1018 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1019 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1020 unregister_trace_block_split(blk_add_trace_split, NULL);
1021 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1022 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1023 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1024 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1025 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1026 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1027 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1028 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1029 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1030 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1031 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1032 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1033 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1034 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1035
1036 tracepoint_synchronize_unregister();
1037 }
1038
1039 /*
1040 * struct blk_io_tracer formatting routines
1041 */
1042
1043 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1044 {
1045 int i = 0;
1046 int tc = t->action >> BLK_TC_SHIFT;
1047
1048 if (t->action == BLK_TN_MESSAGE) {
1049 rwbs[i++] = 'N';
1050 goto out;
1051 }
1052
1053 if (tc & BLK_TC_FLUSH)
1054 rwbs[i++] = 'F';
1055
1056 if (tc & BLK_TC_DISCARD)
1057 rwbs[i++] = 'D';
1058 else if (tc & BLK_TC_WRITE)
1059 rwbs[i++] = 'W';
1060 else if (t->bytes)
1061 rwbs[i++] = 'R';
1062 else
1063 rwbs[i++] = 'N';
1064
1065 if (tc & BLK_TC_FUA)
1066 rwbs[i++] = 'F';
1067 if (tc & BLK_TC_AHEAD)
1068 rwbs[i++] = 'A';
1069 if (tc & BLK_TC_SYNC)
1070 rwbs[i++] = 'S';
1071 if (tc & BLK_TC_META)
1072 rwbs[i++] = 'M';
1073 out:
1074 rwbs[i] = '\0';
1075 }
1076
1077 static inline
1078 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1079 {
1080 return (const struct blk_io_trace *)ent;
1081 }
1082
1083 static inline const void *pdu_start(const struct trace_entry *ent)
1084 {
1085 return te_blk_io_trace(ent) + 1;
1086 }
1087
1088 static inline u32 t_action(const struct trace_entry *ent)
1089 {
1090 return te_blk_io_trace(ent)->action;
1091 }
1092
1093 static inline u32 t_bytes(const struct trace_entry *ent)
1094 {
1095 return te_blk_io_trace(ent)->bytes;
1096 }
1097
1098 static inline u32 t_sec(const struct trace_entry *ent)
1099 {
1100 return te_blk_io_trace(ent)->bytes >> 9;
1101 }
1102
1103 static inline unsigned long long t_sector(const struct trace_entry *ent)
1104 {
1105 return te_blk_io_trace(ent)->sector;
1106 }
1107
1108 static inline __u16 t_error(const struct trace_entry *ent)
1109 {
1110 return te_blk_io_trace(ent)->error;
1111 }
1112
1113 static __u64 get_pdu_int(const struct trace_entry *ent)
1114 {
1115 const __u64 *val = pdu_start(ent);
1116 return be64_to_cpu(*val);
1117 }
1118
1119 static void get_pdu_remap(const struct trace_entry *ent,
1120 struct blk_io_trace_remap *r)
1121 {
1122 const struct blk_io_trace_remap *__r = pdu_start(ent);
1123 __u64 sector_from = __r->sector_from;
1124
1125 r->device_from = be32_to_cpu(__r->device_from);
1126 r->device_to = be32_to_cpu(__r->device_to);
1127 r->sector_from = be64_to_cpu(sector_from);
1128 }
1129
1130 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1131
1132 static void blk_log_action_classic(struct trace_iterator *iter, const char *act)
1133 {
1134 char rwbs[RWBS_LEN];
1135 unsigned long long ts = iter->ts;
1136 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1137 unsigned secs = (unsigned long)ts;
1138 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1139
1140 fill_rwbs(rwbs, t);
1141
1142 trace_seq_printf(&iter->seq,
1143 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1144 MAJOR(t->device), MINOR(t->device), iter->cpu,
1145 secs, nsec_rem, iter->ent->pid, act, rwbs);
1146 }
1147
1148 static void blk_log_action(struct trace_iterator *iter, const char *act)
1149 {
1150 char rwbs[RWBS_LEN];
1151 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1152
1153 fill_rwbs(rwbs, t);
1154 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1155 MAJOR(t->device), MINOR(t->device), act, rwbs);
1156 }
1157
1158 static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1159 {
1160 const unsigned char *pdu_buf;
1161 int pdu_len;
1162 int i, end;
1163
1164 pdu_buf = pdu_start(ent);
1165 pdu_len = te_blk_io_trace(ent)->pdu_len;
1166
1167 if (!pdu_len)
1168 return;
1169
1170 /* find the last zero that needs to be printed */
1171 for (end = pdu_len - 1; end >= 0; end--)
1172 if (pdu_buf[end])
1173 break;
1174 end++;
1175
1176 trace_seq_putc(s, '(');
1177
1178 for (i = 0; i < pdu_len; i++) {
1179
1180 trace_seq_printf(s, "%s%02x",
1181 i == 0 ? "" : " ", pdu_buf[i]);
1182
1183 /*
1184 * stop when the rest is just zeroes and indicate so
1185 * with a ".." appended
1186 */
1187 if (i == end && end != pdu_len - 1) {
1188 trace_seq_puts(s, " ..) ");
1189 return;
1190 }
1191 }
1192
1193 trace_seq_puts(s, ") ");
1194 }
1195
1196 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1197 {
1198 char cmd[TASK_COMM_LEN];
1199
1200 trace_find_cmdline(ent->pid, cmd);
1201
1202 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1203 trace_seq_printf(s, "%u ", t_bytes(ent));
1204 blk_log_dump_pdu(s, ent);
1205 trace_seq_printf(s, "[%s]\n", cmd);
1206 } else {
1207 if (t_sec(ent))
1208 trace_seq_printf(s, "%llu + %u [%s]\n",
1209 t_sector(ent), t_sec(ent), cmd);
1210 else
1211 trace_seq_printf(s, "[%s]\n", cmd);
1212 }
1213 }
1214
1215 static void blk_log_with_error(struct trace_seq *s,
1216 const struct trace_entry *ent)
1217 {
1218 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1219 blk_log_dump_pdu(s, ent);
1220 trace_seq_printf(s, "[%d]\n", t_error(ent));
1221 } else {
1222 if (t_sec(ent))
1223 trace_seq_printf(s, "%llu + %u [%d]\n",
1224 t_sector(ent),
1225 t_sec(ent), t_error(ent));
1226 else
1227 trace_seq_printf(s, "%llu [%d]\n",
1228 t_sector(ent), t_error(ent));
1229 }
1230 }
1231
1232 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1233 {
1234 struct blk_io_trace_remap r = { .device_from = 0, };
1235
1236 get_pdu_remap(ent, &r);
1237 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1238 t_sector(ent), t_sec(ent),
1239 MAJOR(r.device_from), MINOR(r.device_from),
1240 (unsigned long long)r.sector_from);
1241 }
1242
1243 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1244 {
1245 char cmd[TASK_COMM_LEN];
1246
1247 trace_find_cmdline(ent->pid, cmd);
1248
1249 trace_seq_printf(s, "[%s]\n", cmd);
1250 }
1251
1252 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1253 {
1254 char cmd[TASK_COMM_LEN];
1255
1256 trace_find_cmdline(ent->pid, cmd);
1257
1258 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1259 }
1260
1261 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1262 {
1263 char cmd[TASK_COMM_LEN];
1264
1265 trace_find_cmdline(ent->pid, cmd);
1266
1267 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1268 get_pdu_int(ent), cmd);
1269 }
1270
1271 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1272 {
1273 const struct blk_io_trace *t = te_blk_io_trace(ent);
1274
1275 trace_seq_putmem(s, t + 1, t->pdu_len);
1276 trace_seq_putc(s, '\n');
1277 }
1278
1279 /*
1280 * struct tracer operations
1281 */
1282
1283 static void blk_tracer_print_header(struct seq_file *m)
1284 {
1285 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1286 return;
1287 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1288 "# | | | | | |\n");
1289 }
1290
1291 static void blk_tracer_start(struct trace_array *tr)
1292 {
1293 blk_tracer_enabled = true;
1294 }
1295
1296 static int blk_tracer_init(struct trace_array *tr)
1297 {
1298 blk_tr = tr;
1299 blk_tracer_start(tr);
1300 return 0;
1301 }
1302
1303 static void blk_tracer_stop(struct trace_array *tr)
1304 {
1305 blk_tracer_enabled = false;
1306 }
1307
1308 static void blk_tracer_reset(struct trace_array *tr)
1309 {
1310 blk_tracer_stop(tr);
1311 }
1312
1313 static const struct {
1314 const char *act[2];
1315 void (*print)(struct trace_seq *s, const struct trace_entry *ent);
1316 } what2act[] = {
1317 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1318 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1319 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1320 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1321 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1322 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1323 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1324 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1325 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1326 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1327 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1328 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1329 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1330 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1331 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1332 };
1333
1334 static enum print_line_t print_one_line(struct trace_iterator *iter,
1335 bool classic)
1336 {
1337 struct trace_array *tr = iter->tr;
1338 struct trace_seq *s = &iter->seq;
1339 const struct blk_io_trace *t;
1340 u16 what;
1341 bool long_act;
1342 blk_log_action_t *log_action;
1343
1344 t = te_blk_io_trace(iter->ent);
1345 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1346 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1347 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1348
1349 if (t->action == BLK_TN_MESSAGE) {
1350 log_action(iter, long_act ? "message" : "m");
1351 blk_log_msg(s, iter->ent);
1352 return trace_handle_return(s);
1353 }
1354
1355 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1356 trace_seq_printf(s, "Unknown action %x\n", what);
1357 else {
1358 log_action(iter, what2act[what].act[long_act]);
1359 what2act[what].print(s, iter->ent);
1360 }
1361
1362 return trace_handle_return(s);
1363 }
1364
1365 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1366 int flags, struct trace_event *event)
1367 {
1368 return print_one_line(iter, false);
1369 }
1370
1371 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1372 {
1373 struct trace_seq *s = &iter->seq;
1374 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1375 const int offset = offsetof(struct blk_io_trace, sector);
1376 struct blk_io_trace old = {
1377 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1378 .time = iter->ts,
1379 };
1380
1381 trace_seq_putmem(s, &old, offset);
1382 trace_seq_putmem(s, &t->sector,
1383 sizeof(old) - offset + t->pdu_len);
1384 }
1385
1386 static enum print_line_t
1387 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1388 struct trace_event *event)
1389 {
1390 blk_trace_synthesize_old_trace(iter);
1391
1392 return trace_handle_return(&iter->seq);
1393 }
1394
1395 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1396 {
1397 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1398 return TRACE_TYPE_UNHANDLED;
1399
1400 return print_one_line(iter, true);
1401 }
1402
1403 static int
1404 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1405 {
1406 /* don't output context-info for blk_classic output */
1407 if (bit == TRACE_BLK_OPT_CLASSIC) {
1408 if (set)
1409 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1410 else
1411 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1412 }
1413 return 0;
1414 }
1415
1416 static struct tracer blk_tracer __read_mostly = {
1417 .name = "blk",
1418 .init = blk_tracer_init,
1419 .reset = blk_tracer_reset,
1420 .start = blk_tracer_start,
1421 .stop = blk_tracer_stop,
1422 .print_header = blk_tracer_print_header,
1423 .print_line = blk_tracer_print_line,
1424 .flags = &blk_tracer_flags,
1425 .set_flag = blk_tracer_set_flag,
1426 };
1427
1428 static struct trace_event_functions trace_blk_event_funcs = {
1429 .trace = blk_trace_event_print,
1430 .binary = blk_trace_event_print_binary,
1431 };
1432
1433 static struct trace_event trace_blk_event = {
1434 .type = TRACE_BLK,
1435 .funcs = &trace_blk_event_funcs,
1436 };
1437
1438 static int __init init_blk_tracer(void)
1439 {
1440 if (!register_trace_event(&trace_blk_event)) {
1441 pr_warn("Warning: could not register block events\n");
1442 return 1;
1443 }
1444
1445 if (register_tracer(&blk_tracer) != 0) {
1446 pr_warn("Warning: could not register the block tracer\n");
1447 unregister_trace_event(&trace_blk_event);
1448 return 1;
1449 }
1450
1451 return 0;
1452 }
1453
1454 device_initcall(init_blk_tracer);
1455
1456 static int blk_trace_remove_queue(struct request_queue *q)
1457 {
1458 struct blk_trace *bt;
1459
1460 bt = xchg(&q->blk_trace, NULL);
1461 if (bt == NULL)
1462 return -EINVAL;
1463
1464 if (atomic_dec_and_test(&blk_probes_ref))
1465 blk_unregister_tracepoints();
1466
1467 blk_trace_free(bt);
1468 return 0;
1469 }
1470
1471 /*
1472 * Setup everything required to start tracing
1473 */
1474 static int blk_trace_setup_queue(struct request_queue *q,
1475 struct block_device *bdev)
1476 {
1477 struct blk_trace *bt = NULL;
1478 int ret = -ENOMEM;
1479
1480 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1481 if (!bt)
1482 return -ENOMEM;
1483
1484 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1485 if (!bt->msg_data)
1486 goto free_bt;
1487
1488 bt->dev = bdev->bd_dev;
1489 bt->act_mask = (u16)-1;
1490
1491 blk_trace_setup_lba(bt, bdev);
1492
1493 ret = -EBUSY;
1494 if (cmpxchg(&q->blk_trace, NULL, bt))
1495 goto free_bt;
1496
1497 if (atomic_inc_return(&blk_probes_ref) == 1)
1498 blk_register_tracepoints();
1499 return 0;
1500
1501 free_bt:
1502 blk_trace_free(bt);
1503 return ret;
1504 }
1505
1506 /*
1507 * sysfs interface to enable and configure tracing
1508 */
1509
1510 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1511 struct device_attribute *attr,
1512 char *buf);
1513 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1514 struct device_attribute *attr,
1515 const char *buf, size_t count);
1516 #define BLK_TRACE_DEVICE_ATTR(_name) \
1517 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1518 sysfs_blk_trace_attr_show, \
1519 sysfs_blk_trace_attr_store)
1520
1521 static BLK_TRACE_DEVICE_ATTR(enable);
1522 static BLK_TRACE_DEVICE_ATTR(act_mask);
1523 static BLK_TRACE_DEVICE_ATTR(pid);
1524 static BLK_TRACE_DEVICE_ATTR(start_lba);
1525 static BLK_TRACE_DEVICE_ATTR(end_lba);
1526
1527 static struct attribute *blk_trace_attrs[] = {
1528 &dev_attr_enable.attr,
1529 &dev_attr_act_mask.attr,
1530 &dev_attr_pid.attr,
1531 &dev_attr_start_lba.attr,
1532 &dev_attr_end_lba.attr,
1533 NULL
1534 };
1535
1536 struct attribute_group blk_trace_attr_group = {
1537 .name = "trace",
1538 .attrs = blk_trace_attrs,
1539 };
1540
1541 static const struct {
1542 int mask;
1543 const char *str;
1544 } mask_maps[] = {
1545 { BLK_TC_READ, "read" },
1546 { BLK_TC_WRITE, "write" },
1547 { BLK_TC_FLUSH, "flush" },
1548 { BLK_TC_SYNC, "sync" },
1549 { BLK_TC_QUEUE, "queue" },
1550 { BLK_TC_REQUEUE, "requeue" },
1551 { BLK_TC_ISSUE, "issue" },
1552 { BLK_TC_COMPLETE, "complete" },
1553 { BLK_TC_FS, "fs" },
1554 { BLK_TC_PC, "pc" },
1555 { BLK_TC_NOTIFY, "notify" },
1556 { BLK_TC_AHEAD, "ahead" },
1557 { BLK_TC_META, "meta" },
1558 { BLK_TC_DISCARD, "discard" },
1559 { BLK_TC_DRV_DATA, "drv_data" },
1560 { BLK_TC_FUA, "fua" },
1561 };
1562
1563 static int blk_trace_str2mask(const char *str)
1564 {
1565 int i;
1566 int mask = 0;
1567 char *buf, *s, *token;
1568
1569 buf = kstrdup(str, GFP_KERNEL);
1570 if (buf == NULL)
1571 return -ENOMEM;
1572 s = strstrip(buf);
1573
1574 while (1) {
1575 token = strsep(&s, ",");
1576 if (token == NULL)
1577 break;
1578
1579 if (*token == '\0')
1580 continue;
1581
1582 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1583 if (strcasecmp(token, mask_maps[i].str) == 0) {
1584 mask |= mask_maps[i].mask;
1585 break;
1586 }
1587 }
1588 if (i == ARRAY_SIZE(mask_maps)) {
1589 mask = -EINVAL;
1590 break;
1591 }
1592 }
1593 kfree(buf);
1594
1595 return mask;
1596 }
1597
1598 static ssize_t blk_trace_mask2str(char *buf, int mask)
1599 {
1600 int i;
1601 char *p = buf;
1602
1603 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1604 if (mask & mask_maps[i].mask) {
1605 p += sprintf(p, "%s%s",
1606 (p == buf) ? "" : ",", mask_maps[i].str);
1607 }
1608 }
1609 *p++ = '\n';
1610
1611 return p - buf;
1612 }
1613
1614 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1615 {
1616 if (bdev->bd_disk == NULL)
1617 return NULL;
1618
1619 return bdev_get_queue(bdev);
1620 }
1621
1622 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1623 struct device_attribute *attr,
1624 char *buf)
1625 {
1626 struct hd_struct *p = dev_to_part(dev);
1627 struct request_queue *q;
1628 struct block_device *bdev;
1629 ssize_t ret = -ENXIO;
1630
1631 bdev = bdget(part_devt(p));
1632 if (bdev == NULL)
1633 goto out;
1634
1635 q = blk_trace_get_queue(bdev);
1636 if (q == NULL)
1637 goto out_bdput;
1638
1639 mutex_lock(&bdev->bd_mutex);
1640
1641 if (attr == &dev_attr_enable) {
1642 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1643 goto out_unlock_bdev;
1644 }
1645
1646 if (q->blk_trace == NULL)
1647 ret = sprintf(buf, "disabled\n");
1648 else if (attr == &dev_attr_act_mask)
1649 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1650 else if (attr == &dev_attr_pid)
1651 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1652 else if (attr == &dev_attr_start_lba)
1653 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1654 else if (attr == &dev_attr_end_lba)
1655 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1656
1657 out_unlock_bdev:
1658 mutex_unlock(&bdev->bd_mutex);
1659 out_bdput:
1660 bdput(bdev);
1661 out:
1662 return ret;
1663 }
1664
1665 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1666 struct device_attribute *attr,
1667 const char *buf, size_t count)
1668 {
1669 struct block_device *bdev;
1670 struct request_queue *q;
1671 struct hd_struct *p;
1672 u64 value;
1673 ssize_t ret = -EINVAL;
1674
1675 if (count == 0)
1676 goto out;
1677
1678 if (attr == &dev_attr_act_mask) {
1679 if (sscanf(buf, "%llx", &value) != 1) {
1680 /* Assume it is a list of trace category names */
1681 ret = blk_trace_str2mask(buf);
1682 if (ret < 0)
1683 goto out;
1684 value = ret;
1685 }
1686 } else if (sscanf(buf, "%llu", &value) != 1)
1687 goto out;
1688
1689 ret = -ENXIO;
1690
1691 p = dev_to_part(dev);
1692 bdev = bdget(part_devt(p));
1693 if (bdev == NULL)
1694 goto out;
1695
1696 q = blk_trace_get_queue(bdev);
1697 if (q == NULL)
1698 goto out_bdput;
1699
1700 mutex_lock(&bdev->bd_mutex);
1701
1702 if (attr == &dev_attr_enable) {
1703 if (value)
1704 ret = blk_trace_setup_queue(q, bdev);
1705 else
1706 ret = blk_trace_remove_queue(q);
1707 goto out_unlock_bdev;
1708 }
1709
1710 ret = 0;
1711 if (q->blk_trace == NULL)
1712 ret = blk_trace_setup_queue(q, bdev);
1713
1714 if (ret == 0) {
1715 if (attr == &dev_attr_act_mask)
1716 q->blk_trace->act_mask = value;
1717 else if (attr == &dev_attr_pid)
1718 q->blk_trace->pid = value;
1719 else if (attr == &dev_attr_start_lba)
1720 q->blk_trace->start_lba = value;
1721 else if (attr == &dev_attr_end_lba)
1722 q->blk_trace->end_lba = value;
1723 }
1724
1725 out_unlock_bdev:
1726 mutex_unlock(&bdev->bd_mutex);
1727 out_bdput:
1728 bdput(bdev);
1729 out:
1730 return ret ? ret : count;
1731 }
1732
1733 int blk_trace_init_sysfs(struct device *dev)
1734 {
1735 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1736 }
1737
1738 void blk_trace_remove_sysfs(struct device *dev)
1739 {
1740 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1741 }
1742
1743 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1744
1745 #ifdef CONFIG_EVENT_TRACING
1746
1747 void blk_dump_cmd(char *buf, struct request *rq)
1748 {
1749 int i, end;
1750 int len = rq->cmd_len;
1751 unsigned char *cmd = rq->cmd;
1752
1753 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1754 buf[0] = '\0';
1755 return;
1756 }
1757
1758 for (end = len - 1; end >= 0; end--)
1759 if (cmd[end])
1760 break;
1761 end++;
1762
1763 for (i = 0; i < len; i++) {
1764 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1765 if (i == end && end != len - 1) {
1766 sprintf(buf, " ..");
1767 break;
1768 }
1769 }
1770 }
1771
1772 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1773 {
1774 int i = 0;
1775
1776 if (rw & REQ_FLUSH)
1777 rwbs[i++] = 'F';
1778
1779 if (rw & WRITE)
1780 rwbs[i++] = 'W';
1781 else if (rw & REQ_DISCARD)
1782 rwbs[i++] = 'D';
1783 else if (bytes)
1784 rwbs[i++] = 'R';
1785 else
1786 rwbs[i++] = 'N';
1787
1788 if (rw & REQ_FUA)
1789 rwbs[i++] = 'F';
1790 if (rw & REQ_RAHEAD)
1791 rwbs[i++] = 'A';
1792 if (rw & REQ_SYNC)
1793 rwbs[i++] = 'S';
1794 if (rw & REQ_META)
1795 rwbs[i++] = 'M';
1796 if (rw & REQ_SECURE)
1797 rwbs[i++] = 'E';
1798
1799 rwbs[i] = '\0';
1800 }
1801 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1802
1803 #endif /* CONFIG_EVENT_TRACING */
1804
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