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Merge tag 'hwspinlock-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad...
[deliverable/linux.git] / kernel / trace / blktrace.c
1 /*
2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
16 *
17 */
18 #include <linux/kernel.h>
19 #include <linux/blkdev.h>
20 #include <linux/blktrace_api.h>
21 #include <linux/percpu.h>
22 #include <linux/init.h>
23 #include <linux/mutex.h>
24 #include <linux/slab.h>
25 #include <linux/debugfs.h>
26 #include <linux/export.h>
27 #include <linux/time.h>
28 #include <linux/uaccess.h>
29 #include <linux/list.h>
30
31 #include <trace/events/block.h>
32
33 #include "trace_output.h"
34
35 #ifdef CONFIG_BLK_DEV_IO_TRACE
36
37 static unsigned int blktrace_seq __read_mostly = 1;
38
39 static struct trace_array *blk_tr;
40 static bool blk_tracer_enabled __read_mostly;
41
42 static LIST_HEAD(running_trace_list);
43 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
44
45 /* Select an alternative, minimalistic output than the original one */
46 #define TRACE_BLK_OPT_CLASSIC 0x1
47
48 static struct tracer_opt blk_tracer_opts[] = {
49 /* Default disable the minimalistic output */
50 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
51 { }
52 };
53
54 static struct tracer_flags blk_tracer_flags = {
55 .val = 0,
56 .opts = blk_tracer_opts,
57 };
58
59 /* Global reference count of probes */
60 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
61
62 static void blk_register_tracepoints(void);
63 static void blk_unregister_tracepoints(void);
64
65 /*
66 * Send out a notify message.
67 */
68 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
69 const void *data, size_t len)
70 {
71 struct blk_io_trace *t;
72 struct ring_buffer_event *event = NULL;
73 struct ring_buffer *buffer = NULL;
74 int pc = 0;
75 int cpu = smp_processor_id();
76 bool blk_tracer = blk_tracer_enabled;
77
78 if (blk_tracer) {
79 buffer = blk_tr->trace_buffer.buffer;
80 pc = preempt_count();
81 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
82 sizeof(*t) + len,
83 0, pc);
84 if (!event)
85 return;
86 t = ring_buffer_event_data(event);
87 goto record_it;
88 }
89
90 if (!bt->rchan)
91 return;
92
93 t = relay_reserve(bt->rchan, sizeof(*t) + len);
94 if (t) {
95 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
96 t->time = ktime_to_ns(ktime_get());
97 record_it:
98 t->device = bt->dev;
99 t->action = action;
100 t->pid = pid;
101 t->cpu = cpu;
102 t->pdu_len = len;
103 memcpy((void *) t + sizeof(*t), data, len);
104
105 if (blk_tracer)
106 trace_buffer_unlock_commit(buffer, event, 0, pc);
107 }
108 }
109
110 /*
111 * Send out a notify for this process, if we haven't done so since a trace
112 * started
113 */
114 static void trace_note_tsk(struct task_struct *tsk)
115 {
116 unsigned long flags;
117 struct blk_trace *bt;
118
119 tsk->btrace_seq = blktrace_seq;
120 spin_lock_irqsave(&running_trace_lock, flags);
121 list_for_each_entry(bt, &running_trace_list, running_list) {
122 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
123 sizeof(tsk->comm));
124 }
125 spin_unlock_irqrestore(&running_trace_lock, flags);
126 }
127
128 static void trace_note_time(struct blk_trace *bt)
129 {
130 struct timespec now;
131 unsigned long flags;
132 u32 words[2];
133
134 getnstimeofday(&now);
135 words[0] = now.tv_sec;
136 words[1] = now.tv_nsec;
137
138 local_irq_save(flags);
139 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
140 local_irq_restore(flags);
141 }
142
143 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
144 {
145 int n;
146 va_list args;
147 unsigned long flags;
148 char *buf;
149
150 if (unlikely(bt->trace_state != Blktrace_running &&
151 !blk_tracer_enabled))
152 return;
153
154 /*
155 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
156 * message to the trace.
157 */
158 if (!(bt->act_mask & BLK_TC_NOTIFY))
159 return;
160
161 local_irq_save(flags);
162 buf = this_cpu_ptr(bt->msg_data);
163 va_start(args, fmt);
164 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
165 va_end(args);
166
167 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
168 local_irq_restore(flags);
169 }
170 EXPORT_SYMBOL_GPL(__trace_note_message);
171
172 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
173 pid_t pid)
174 {
175 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
176 return 1;
177 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
178 return 1;
179 if (bt->pid && pid != bt->pid)
180 return 1;
181
182 return 0;
183 }
184
185 /*
186 * Data direction bit lookup
187 */
188 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
189 BLK_TC_ACT(BLK_TC_WRITE) };
190
191 #define BLK_TC_RAHEAD BLK_TC_AHEAD
192
193 /* The ilog2() calls fall out because they're constant */
194 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
195 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
196
197 /*
198 * The worker for the various blk_add_trace*() types. Fills out a
199 * blk_io_trace structure and places it in a per-cpu subbuffer.
200 */
201 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
202 int rw, u32 what, int error, int pdu_len, void *pdu_data)
203 {
204 struct task_struct *tsk = current;
205 struct ring_buffer_event *event = NULL;
206 struct ring_buffer *buffer = NULL;
207 struct blk_io_trace *t;
208 unsigned long flags = 0;
209 unsigned long *sequence;
210 pid_t pid;
211 int cpu, pc = 0;
212 bool blk_tracer = blk_tracer_enabled;
213
214 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
215 return;
216
217 what |= ddir_act[rw & WRITE];
218 what |= MASK_TC_BIT(rw, SYNC);
219 what |= MASK_TC_BIT(rw, RAHEAD);
220 what |= MASK_TC_BIT(rw, META);
221 what |= MASK_TC_BIT(rw, DISCARD);
222 what |= MASK_TC_BIT(rw, FLUSH);
223 what |= MASK_TC_BIT(rw, FUA);
224
225 pid = tsk->pid;
226 if (act_log_check(bt, what, sector, pid))
227 return;
228 cpu = raw_smp_processor_id();
229
230 if (blk_tracer) {
231 tracing_record_cmdline(current);
232
233 buffer = blk_tr->trace_buffer.buffer;
234 pc = preempt_count();
235 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
236 sizeof(*t) + pdu_len,
237 0, pc);
238 if (!event)
239 return;
240 t = ring_buffer_event_data(event);
241 goto record_it;
242 }
243
244 if (unlikely(tsk->btrace_seq != blktrace_seq))
245 trace_note_tsk(tsk);
246
247 /*
248 * A word about the locking here - we disable interrupts to reserve
249 * some space in the relay per-cpu buffer, to prevent an irq
250 * from coming in and stepping on our toes.
251 */
252 local_irq_save(flags);
253 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
254 if (t) {
255 sequence = per_cpu_ptr(bt->sequence, cpu);
256
257 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
258 t->sequence = ++(*sequence);
259 t->time = ktime_to_ns(ktime_get());
260 record_it:
261 /*
262 * These two are not needed in ftrace as they are in the
263 * generic trace_entry, filled by tracing_generic_entry_update,
264 * but for the trace_event->bin() synthesizer benefit we do it
265 * here too.
266 */
267 t->cpu = cpu;
268 t->pid = pid;
269
270 t->sector = sector;
271 t->bytes = bytes;
272 t->action = what;
273 t->device = bt->dev;
274 t->error = error;
275 t->pdu_len = pdu_len;
276
277 if (pdu_len)
278 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
279
280 if (blk_tracer) {
281 trace_buffer_unlock_commit(buffer, event, 0, pc);
282 return;
283 }
284 }
285
286 local_irq_restore(flags);
287 }
288
289 static struct dentry *blk_tree_root;
290 static DEFINE_MUTEX(blk_tree_mutex);
291
292 static void blk_trace_free(struct blk_trace *bt)
293 {
294 debugfs_remove(bt->msg_file);
295 debugfs_remove(bt->dropped_file);
296 relay_close(bt->rchan);
297 debugfs_remove(bt->dir);
298 free_percpu(bt->sequence);
299 free_percpu(bt->msg_data);
300 kfree(bt);
301 }
302
303 static void blk_trace_cleanup(struct blk_trace *bt)
304 {
305 blk_trace_free(bt);
306 if (atomic_dec_and_test(&blk_probes_ref))
307 blk_unregister_tracepoints();
308 }
309
310 int blk_trace_remove(struct request_queue *q)
311 {
312 struct blk_trace *bt;
313
314 bt = xchg(&q->blk_trace, NULL);
315 if (!bt)
316 return -EINVAL;
317
318 if (bt->trace_state != Blktrace_running)
319 blk_trace_cleanup(bt);
320
321 return 0;
322 }
323 EXPORT_SYMBOL_GPL(blk_trace_remove);
324
325 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
326 size_t count, loff_t *ppos)
327 {
328 struct blk_trace *bt = filp->private_data;
329 char buf[16];
330
331 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
332
333 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
334 }
335
336 static const struct file_operations blk_dropped_fops = {
337 .owner = THIS_MODULE,
338 .open = simple_open,
339 .read = blk_dropped_read,
340 .llseek = default_llseek,
341 };
342
343 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
344 size_t count, loff_t *ppos)
345 {
346 char *msg;
347 struct blk_trace *bt;
348
349 if (count >= BLK_TN_MAX_MSG)
350 return -EINVAL;
351
352 msg = kmalloc(count + 1, GFP_KERNEL);
353 if (msg == NULL)
354 return -ENOMEM;
355
356 if (copy_from_user(msg, buffer, count)) {
357 kfree(msg);
358 return -EFAULT;
359 }
360
361 msg[count] = '\0';
362 bt = filp->private_data;
363 __trace_note_message(bt, "%s", msg);
364 kfree(msg);
365
366 return count;
367 }
368
369 static const struct file_operations blk_msg_fops = {
370 .owner = THIS_MODULE,
371 .open = simple_open,
372 .write = blk_msg_write,
373 .llseek = noop_llseek,
374 };
375
376 /*
377 * Keep track of how many times we encountered a full subbuffer, to aid
378 * the user space app in telling how many lost events there were.
379 */
380 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
381 void *prev_subbuf, size_t prev_padding)
382 {
383 struct blk_trace *bt;
384
385 if (!relay_buf_full(buf))
386 return 1;
387
388 bt = buf->chan->private_data;
389 atomic_inc(&bt->dropped);
390 return 0;
391 }
392
393 static int blk_remove_buf_file_callback(struct dentry *dentry)
394 {
395 debugfs_remove(dentry);
396
397 return 0;
398 }
399
400 static struct dentry *blk_create_buf_file_callback(const char *filename,
401 struct dentry *parent,
402 umode_t mode,
403 struct rchan_buf *buf,
404 int *is_global)
405 {
406 return debugfs_create_file(filename, mode, parent, buf,
407 &relay_file_operations);
408 }
409
410 static struct rchan_callbacks blk_relay_callbacks = {
411 .subbuf_start = blk_subbuf_start_callback,
412 .create_buf_file = blk_create_buf_file_callback,
413 .remove_buf_file = blk_remove_buf_file_callback,
414 };
415
416 static void blk_trace_setup_lba(struct blk_trace *bt,
417 struct block_device *bdev)
418 {
419 struct hd_struct *part = NULL;
420
421 if (bdev)
422 part = bdev->bd_part;
423
424 if (part) {
425 bt->start_lba = part->start_sect;
426 bt->end_lba = part->start_sect + part->nr_sects;
427 } else {
428 bt->start_lba = 0;
429 bt->end_lba = -1ULL;
430 }
431 }
432
433 /*
434 * Setup everything required to start tracing
435 */
436 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
437 struct block_device *bdev,
438 struct blk_user_trace_setup *buts)
439 {
440 struct blk_trace *old_bt, *bt = NULL;
441 struct dentry *dir = NULL;
442 int ret;
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 old_bt = xchg(&q->blk_trace, bt);
523 if (old_bt) {
524 (void) xchg(&q->blk_trace, old_bt);
525 goto err;
526 }
527
528 if (atomic_inc_return(&blk_probes_ref) == 1)
529 blk_register_tracepoints();
530
531 return 0;
532 err:
533 blk_trace_free(bt);
534 return ret;
535 }
536
537 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
538 struct block_device *bdev,
539 char __user *arg)
540 {
541 struct blk_user_trace_setup buts;
542 int ret;
543
544 ret = copy_from_user(&buts, arg, sizeof(buts));
545 if (ret)
546 return -EFAULT;
547
548 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
549 if (ret)
550 return ret;
551
552 if (copy_to_user(arg, &buts, sizeof(buts))) {
553 blk_trace_remove(q);
554 return -EFAULT;
555 }
556 return 0;
557 }
558 EXPORT_SYMBOL_GPL(blk_trace_setup);
559
560 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
561 static int compat_blk_trace_setup(struct request_queue *q, char *name,
562 dev_t dev, struct block_device *bdev,
563 char __user *arg)
564 {
565 struct blk_user_trace_setup buts;
566 struct compat_blk_user_trace_setup cbuts;
567 int ret;
568
569 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
570 return -EFAULT;
571
572 buts = (struct blk_user_trace_setup) {
573 .act_mask = cbuts.act_mask,
574 .buf_size = cbuts.buf_size,
575 .buf_nr = cbuts.buf_nr,
576 .start_lba = cbuts.start_lba,
577 .end_lba = cbuts.end_lba,
578 .pid = cbuts.pid,
579 };
580
581 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
582 if (ret)
583 return ret;
584
585 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
586 blk_trace_remove(q);
587 return -EFAULT;
588 }
589
590 return 0;
591 }
592 #endif
593
594 int blk_trace_startstop(struct request_queue *q, int start)
595 {
596 int ret;
597 struct blk_trace *bt = q->blk_trace;
598
599 if (bt == NULL)
600 return -EINVAL;
601
602 /*
603 * For starting a trace, we can transition from a setup or stopped
604 * trace. For stopping a trace, the state must be running
605 */
606 ret = -EINVAL;
607 if (start) {
608 if (bt->trace_state == Blktrace_setup ||
609 bt->trace_state == Blktrace_stopped) {
610 blktrace_seq++;
611 smp_mb();
612 bt->trace_state = Blktrace_running;
613 spin_lock_irq(&running_trace_lock);
614 list_add(&bt->running_list, &running_trace_list);
615 spin_unlock_irq(&running_trace_lock);
616
617 trace_note_time(bt);
618 ret = 0;
619 }
620 } else {
621 if (bt->trace_state == Blktrace_running) {
622 bt->trace_state = Blktrace_stopped;
623 spin_lock_irq(&running_trace_lock);
624 list_del_init(&bt->running_list);
625 spin_unlock_irq(&running_trace_lock);
626 relay_flush(bt->rchan);
627 ret = 0;
628 }
629 }
630
631 return ret;
632 }
633 EXPORT_SYMBOL_GPL(blk_trace_startstop);
634
635 /**
636 * blk_trace_ioctl: - handle the ioctls associated with tracing
637 * @bdev: the block device
638 * @cmd: the ioctl cmd
639 * @arg: the argument data, if any
640 *
641 **/
642 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
643 {
644 struct request_queue *q;
645 int ret, start = 0;
646 char b[BDEVNAME_SIZE];
647
648 q = bdev_get_queue(bdev);
649 if (!q)
650 return -ENXIO;
651
652 mutex_lock(&bdev->bd_mutex);
653
654 switch (cmd) {
655 case BLKTRACESETUP:
656 bdevname(bdev, b);
657 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
658 break;
659 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
660 case BLKTRACESETUP32:
661 bdevname(bdev, b);
662 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
663 break;
664 #endif
665 case BLKTRACESTART:
666 start = 1;
667 case BLKTRACESTOP:
668 ret = blk_trace_startstop(q, start);
669 break;
670 case BLKTRACETEARDOWN:
671 ret = blk_trace_remove(q);
672 break;
673 default:
674 ret = -ENOTTY;
675 break;
676 }
677
678 mutex_unlock(&bdev->bd_mutex);
679 return ret;
680 }
681
682 /**
683 * blk_trace_shutdown: - stop and cleanup trace structures
684 * @q: the request queue associated with the device
685 *
686 **/
687 void blk_trace_shutdown(struct request_queue *q)
688 {
689 if (q->blk_trace) {
690 blk_trace_startstop(q, 0);
691 blk_trace_remove(q);
692 }
693 }
694
695 /*
696 * blktrace probes
697 */
698
699 /**
700 * blk_add_trace_rq - Add a trace for a request oriented action
701 * @q: queue the io is for
702 * @rq: the source request
703 * @nr_bytes: number of completed bytes
704 * @what: the action
705 *
706 * Description:
707 * Records an action against a request. Will log the bio offset + size.
708 *
709 **/
710 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
711 unsigned int nr_bytes, u32 what)
712 {
713 struct blk_trace *bt = q->blk_trace;
714
715 if (likely(!bt))
716 return;
717
718 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
719 what |= BLK_TC_ACT(BLK_TC_PC);
720 __blk_add_trace(bt, 0, nr_bytes, rq->cmd_flags,
721 what, rq->errors, rq->cmd_len, rq->cmd);
722 } else {
723 what |= BLK_TC_ACT(BLK_TC_FS);
724 __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes,
725 rq->cmd_flags, what, rq->errors, 0, NULL);
726 }
727 }
728
729 static void blk_add_trace_rq_abort(void *ignore,
730 struct request_queue *q, struct request *rq)
731 {
732 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT);
733 }
734
735 static void blk_add_trace_rq_insert(void *ignore,
736 struct request_queue *q, struct request *rq)
737 {
738 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT);
739 }
740
741 static void blk_add_trace_rq_issue(void *ignore,
742 struct request_queue *q, struct request *rq)
743 {
744 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE);
745 }
746
747 static void blk_add_trace_rq_requeue(void *ignore,
748 struct request_queue *q,
749 struct request *rq)
750 {
751 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE);
752 }
753
754 static void blk_add_trace_rq_complete(void *ignore,
755 struct request_queue *q,
756 struct request *rq,
757 unsigned int nr_bytes)
758 {
759 blk_add_trace_rq(q, rq, nr_bytes, BLK_TA_COMPLETE);
760 }
761
762 /**
763 * blk_add_trace_bio - Add a trace for a bio oriented action
764 * @q: queue the io is for
765 * @bio: the source bio
766 * @what: the action
767 * @error: error, if any
768 *
769 * Description:
770 * Records an action against a bio. Will log the bio offset + size.
771 *
772 **/
773 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
774 u32 what, int error)
775 {
776 struct blk_trace *bt = q->blk_trace;
777
778 if (likely(!bt))
779 return;
780
781 if (!error && !bio_flagged(bio, BIO_UPTODATE))
782 error = EIO;
783
784 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
785 bio->bi_rw, what, error, 0, NULL);
786 }
787
788 static void blk_add_trace_bio_bounce(void *ignore,
789 struct request_queue *q, struct bio *bio)
790 {
791 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
792 }
793
794 static void blk_add_trace_bio_complete(void *ignore,
795 struct request_queue *q, struct bio *bio,
796 int error)
797 {
798 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
799 }
800
801 static void blk_add_trace_bio_backmerge(void *ignore,
802 struct request_queue *q,
803 struct request *rq,
804 struct bio *bio)
805 {
806 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
807 }
808
809 static void blk_add_trace_bio_frontmerge(void *ignore,
810 struct request_queue *q,
811 struct request *rq,
812 struct bio *bio)
813 {
814 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
815 }
816
817 static void blk_add_trace_bio_queue(void *ignore,
818 struct request_queue *q, struct bio *bio)
819 {
820 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
821 }
822
823 static void blk_add_trace_getrq(void *ignore,
824 struct request_queue *q,
825 struct bio *bio, int rw)
826 {
827 if (bio)
828 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
829 else {
830 struct blk_trace *bt = q->blk_trace;
831
832 if (bt)
833 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
834 }
835 }
836
837
838 static void blk_add_trace_sleeprq(void *ignore,
839 struct request_queue *q,
840 struct bio *bio, int rw)
841 {
842 if (bio)
843 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
844 else {
845 struct blk_trace *bt = q->blk_trace;
846
847 if (bt)
848 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
849 0, 0, NULL);
850 }
851 }
852
853 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
854 {
855 struct blk_trace *bt = q->blk_trace;
856
857 if (bt)
858 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
859 }
860
861 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
862 unsigned int depth, bool explicit)
863 {
864 struct blk_trace *bt = q->blk_trace;
865
866 if (bt) {
867 __be64 rpdu = cpu_to_be64(depth);
868 u32 what;
869
870 if (explicit)
871 what = BLK_TA_UNPLUG_IO;
872 else
873 what = BLK_TA_UNPLUG_TIMER;
874
875 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
876 }
877 }
878
879 static void blk_add_trace_split(void *ignore,
880 struct request_queue *q, struct bio *bio,
881 unsigned int pdu)
882 {
883 struct blk_trace *bt = q->blk_trace;
884
885 if (bt) {
886 __be64 rpdu = cpu_to_be64(pdu);
887
888 __blk_add_trace(bt, bio->bi_iter.bi_sector,
889 bio->bi_iter.bi_size, bio->bi_rw, BLK_TA_SPLIT,
890 !bio_flagged(bio, BIO_UPTODATE),
891 sizeof(rpdu), &rpdu);
892 }
893 }
894
895 /**
896 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
897 * @ignore: trace callback data parameter (not used)
898 * @q: queue the io is for
899 * @bio: the source bio
900 * @dev: target device
901 * @from: source sector
902 *
903 * Description:
904 * Device mapper or raid target sometimes need to split a bio because
905 * it spans a stripe (or similar). Add a trace for that action.
906 *
907 **/
908 static void blk_add_trace_bio_remap(void *ignore,
909 struct request_queue *q, struct bio *bio,
910 dev_t dev, sector_t from)
911 {
912 struct blk_trace *bt = q->blk_trace;
913 struct blk_io_trace_remap r;
914
915 if (likely(!bt))
916 return;
917
918 r.device_from = cpu_to_be32(dev);
919 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
920 r.sector_from = cpu_to_be64(from);
921
922 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
923 bio->bi_rw, BLK_TA_REMAP,
924 !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
925 }
926
927 /**
928 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
929 * @ignore: trace callback data parameter (not used)
930 * @q: queue the io is for
931 * @rq: the source request
932 * @dev: target device
933 * @from: source sector
934 *
935 * Description:
936 * Device mapper remaps request to other devices.
937 * Add a trace for that action.
938 *
939 **/
940 static void blk_add_trace_rq_remap(void *ignore,
941 struct request_queue *q,
942 struct request *rq, dev_t dev,
943 sector_t from)
944 {
945 struct blk_trace *bt = q->blk_trace;
946 struct blk_io_trace_remap r;
947
948 if (likely(!bt))
949 return;
950
951 r.device_from = cpu_to_be32(dev);
952 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
953 r.sector_from = cpu_to_be64(from);
954
955 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
956 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
957 sizeof(r), &r);
958 }
959
960 /**
961 * blk_add_driver_data - Add binary message with driver-specific data
962 * @q: queue the io is for
963 * @rq: io request
964 * @data: driver-specific data
965 * @len: length of driver-specific data
966 *
967 * Description:
968 * Some drivers might want to write driver-specific data per request.
969 *
970 **/
971 void blk_add_driver_data(struct request_queue *q,
972 struct request *rq,
973 void *data, size_t len)
974 {
975 struct blk_trace *bt = q->blk_trace;
976
977 if (likely(!bt))
978 return;
979
980 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
981 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
982 BLK_TA_DRV_DATA, rq->errors, len, data);
983 else
984 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
985 BLK_TA_DRV_DATA, rq->errors, len, data);
986 }
987 EXPORT_SYMBOL_GPL(blk_add_driver_data);
988
989 static void blk_register_tracepoints(void)
990 {
991 int ret;
992
993 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
994 WARN_ON(ret);
995 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1006 WARN_ON(ret);
1007 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1008 WARN_ON(ret);
1009 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1010 WARN_ON(ret);
1011 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1012 WARN_ON(ret);
1013 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1014 WARN_ON(ret);
1015 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1016 WARN_ON(ret);
1017 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1018 WARN_ON(ret);
1019 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1020 WARN_ON(ret);
1021 ret = register_trace_block_split(blk_add_trace_split, NULL);
1022 WARN_ON(ret);
1023 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1024 WARN_ON(ret);
1025 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1026 WARN_ON(ret);
1027 }
1028
1029 static void blk_unregister_tracepoints(void)
1030 {
1031 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1032 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1033 unregister_trace_block_split(blk_add_trace_split, NULL);
1034 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1035 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1036 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1037 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1038 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1039 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1040 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1041 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1042 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1043 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1044 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1045 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1046 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1047 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1048
1049 tracepoint_synchronize_unregister();
1050 }
1051
1052 /*
1053 * struct blk_io_tracer formatting routines
1054 */
1055
1056 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1057 {
1058 int i = 0;
1059 int tc = t->action >> BLK_TC_SHIFT;
1060
1061 if (t->action == BLK_TN_MESSAGE) {
1062 rwbs[i++] = 'N';
1063 goto out;
1064 }
1065
1066 if (tc & BLK_TC_FLUSH)
1067 rwbs[i++] = 'F';
1068
1069 if (tc & BLK_TC_DISCARD)
1070 rwbs[i++] = 'D';
1071 else if (tc & BLK_TC_WRITE)
1072 rwbs[i++] = 'W';
1073 else if (t->bytes)
1074 rwbs[i++] = 'R';
1075 else
1076 rwbs[i++] = 'N';
1077
1078 if (tc & BLK_TC_FUA)
1079 rwbs[i++] = 'F';
1080 if (tc & BLK_TC_AHEAD)
1081 rwbs[i++] = 'A';
1082 if (tc & BLK_TC_SYNC)
1083 rwbs[i++] = 'S';
1084 if (tc & BLK_TC_META)
1085 rwbs[i++] = 'M';
1086 out:
1087 rwbs[i] = '\0';
1088 }
1089
1090 static inline
1091 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1092 {
1093 return (const struct blk_io_trace *)ent;
1094 }
1095
1096 static inline const void *pdu_start(const struct trace_entry *ent)
1097 {
1098 return te_blk_io_trace(ent) + 1;
1099 }
1100
1101 static inline u32 t_action(const struct trace_entry *ent)
1102 {
1103 return te_blk_io_trace(ent)->action;
1104 }
1105
1106 static inline u32 t_bytes(const struct trace_entry *ent)
1107 {
1108 return te_blk_io_trace(ent)->bytes;
1109 }
1110
1111 static inline u32 t_sec(const struct trace_entry *ent)
1112 {
1113 return te_blk_io_trace(ent)->bytes >> 9;
1114 }
1115
1116 static inline unsigned long long t_sector(const struct trace_entry *ent)
1117 {
1118 return te_blk_io_trace(ent)->sector;
1119 }
1120
1121 static inline __u16 t_error(const struct trace_entry *ent)
1122 {
1123 return te_blk_io_trace(ent)->error;
1124 }
1125
1126 static __u64 get_pdu_int(const struct trace_entry *ent)
1127 {
1128 const __u64 *val = pdu_start(ent);
1129 return be64_to_cpu(*val);
1130 }
1131
1132 static void get_pdu_remap(const struct trace_entry *ent,
1133 struct blk_io_trace_remap *r)
1134 {
1135 const struct blk_io_trace_remap *__r = pdu_start(ent);
1136 __u64 sector_from = __r->sector_from;
1137
1138 r->device_from = be32_to_cpu(__r->device_from);
1139 r->device_to = be32_to_cpu(__r->device_to);
1140 r->sector_from = be64_to_cpu(sector_from);
1141 }
1142
1143 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1144
1145 static void blk_log_action_classic(struct trace_iterator *iter, const char *act)
1146 {
1147 char rwbs[RWBS_LEN];
1148 unsigned long long ts = iter->ts;
1149 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1150 unsigned secs = (unsigned long)ts;
1151 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1152
1153 fill_rwbs(rwbs, t);
1154
1155 trace_seq_printf(&iter->seq,
1156 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1157 MAJOR(t->device), MINOR(t->device), iter->cpu,
1158 secs, nsec_rem, iter->ent->pid, act, rwbs);
1159 }
1160
1161 static void blk_log_action(struct trace_iterator *iter, const char *act)
1162 {
1163 char rwbs[RWBS_LEN];
1164 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1165
1166 fill_rwbs(rwbs, t);
1167 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1168 MAJOR(t->device), MINOR(t->device), act, rwbs);
1169 }
1170
1171 static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1172 {
1173 const unsigned char *pdu_buf;
1174 int pdu_len;
1175 int i, end;
1176
1177 pdu_buf = pdu_start(ent);
1178 pdu_len = te_blk_io_trace(ent)->pdu_len;
1179
1180 if (!pdu_len)
1181 return;
1182
1183 /* find the last zero that needs to be printed */
1184 for (end = pdu_len - 1; end >= 0; end--)
1185 if (pdu_buf[end])
1186 break;
1187 end++;
1188
1189 trace_seq_putc(s, '(');
1190
1191 for (i = 0; i < pdu_len; i++) {
1192
1193 trace_seq_printf(s, "%s%02x",
1194 i == 0 ? "" : " ", pdu_buf[i]);
1195
1196 /*
1197 * stop when the rest is just zeroes and indicate so
1198 * with a ".." appended
1199 */
1200 if (i == end && end != pdu_len - 1) {
1201 trace_seq_puts(s, " ..) ");
1202 return;
1203 }
1204 }
1205
1206 trace_seq_puts(s, ") ");
1207 }
1208
1209 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1210 {
1211 char cmd[TASK_COMM_LEN];
1212
1213 trace_find_cmdline(ent->pid, cmd);
1214
1215 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1216 trace_seq_printf(s, "%u ", t_bytes(ent));
1217 blk_log_dump_pdu(s, ent);
1218 trace_seq_printf(s, "[%s]\n", cmd);
1219 } else {
1220 if (t_sec(ent))
1221 trace_seq_printf(s, "%llu + %u [%s]\n",
1222 t_sector(ent), t_sec(ent), cmd);
1223 else
1224 trace_seq_printf(s, "[%s]\n", cmd);
1225 }
1226 }
1227
1228 static void blk_log_with_error(struct trace_seq *s,
1229 const struct trace_entry *ent)
1230 {
1231 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1232 blk_log_dump_pdu(s, ent);
1233 trace_seq_printf(s, "[%d]\n", t_error(ent));
1234 } else {
1235 if (t_sec(ent))
1236 trace_seq_printf(s, "%llu + %u [%d]\n",
1237 t_sector(ent),
1238 t_sec(ent), t_error(ent));
1239 else
1240 trace_seq_printf(s, "%llu [%d]\n",
1241 t_sector(ent), t_error(ent));
1242 }
1243 }
1244
1245 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1246 {
1247 struct blk_io_trace_remap r = { .device_from = 0, };
1248
1249 get_pdu_remap(ent, &r);
1250 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1251 t_sector(ent), t_sec(ent),
1252 MAJOR(r.device_from), MINOR(r.device_from),
1253 (unsigned long long)r.sector_from);
1254 }
1255
1256 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1257 {
1258 char cmd[TASK_COMM_LEN];
1259
1260 trace_find_cmdline(ent->pid, cmd);
1261
1262 trace_seq_printf(s, "[%s]\n", cmd);
1263 }
1264
1265 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1266 {
1267 char cmd[TASK_COMM_LEN];
1268
1269 trace_find_cmdline(ent->pid, cmd);
1270
1271 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1272 }
1273
1274 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1275 {
1276 char cmd[TASK_COMM_LEN];
1277
1278 trace_find_cmdline(ent->pid, cmd);
1279
1280 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1281 get_pdu_int(ent), cmd);
1282 }
1283
1284 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1285 {
1286 const struct blk_io_trace *t = te_blk_io_trace(ent);
1287
1288 trace_seq_putmem(s, t + 1, t->pdu_len);
1289 trace_seq_putc(s, '\n');
1290 }
1291
1292 /*
1293 * struct tracer operations
1294 */
1295
1296 static void blk_tracer_print_header(struct seq_file *m)
1297 {
1298 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1299 return;
1300 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1301 "# | | | | | |\n");
1302 }
1303
1304 static void blk_tracer_start(struct trace_array *tr)
1305 {
1306 blk_tracer_enabled = true;
1307 }
1308
1309 static int blk_tracer_init(struct trace_array *tr)
1310 {
1311 blk_tr = tr;
1312 blk_tracer_start(tr);
1313 return 0;
1314 }
1315
1316 static void blk_tracer_stop(struct trace_array *tr)
1317 {
1318 blk_tracer_enabled = false;
1319 }
1320
1321 static void blk_tracer_reset(struct trace_array *tr)
1322 {
1323 blk_tracer_stop(tr);
1324 }
1325
1326 static const struct {
1327 const char *act[2];
1328 void (*print)(struct trace_seq *s, const struct trace_entry *ent);
1329 } what2act[] = {
1330 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1331 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1332 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1333 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1334 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1335 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1336 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1337 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1338 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1339 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1340 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1341 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1342 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1343 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1344 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1345 };
1346
1347 static enum print_line_t print_one_line(struct trace_iterator *iter,
1348 bool classic)
1349 {
1350 struct trace_seq *s = &iter->seq;
1351 const struct blk_io_trace *t;
1352 u16 what;
1353 bool long_act;
1354 blk_log_action_t *log_action;
1355
1356 t = te_blk_io_trace(iter->ent);
1357 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1358 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1359 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1360
1361 if (t->action == BLK_TN_MESSAGE) {
1362 log_action(iter, long_act ? "message" : "m");
1363 blk_log_msg(s, iter->ent);
1364 }
1365
1366 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1367 trace_seq_printf(s, "Unknown action %x\n", what);
1368 else {
1369 log_action(iter, what2act[what].act[long_act]);
1370 what2act[what].print(s, iter->ent);
1371 }
1372
1373 return trace_handle_return(s);
1374 }
1375
1376 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1377 int flags, struct trace_event *event)
1378 {
1379 return print_one_line(iter, false);
1380 }
1381
1382 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1383 {
1384 struct trace_seq *s = &iter->seq;
1385 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1386 const int offset = offsetof(struct blk_io_trace, sector);
1387 struct blk_io_trace old = {
1388 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1389 .time = iter->ts,
1390 };
1391
1392 trace_seq_putmem(s, &old, offset);
1393 trace_seq_putmem(s, &t->sector,
1394 sizeof(old) - offset + t->pdu_len);
1395 }
1396
1397 static enum print_line_t
1398 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1399 struct trace_event *event)
1400 {
1401 blk_trace_synthesize_old_trace(iter);
1402
1403 return trace_handle_return(&iter->seq);
1404 }
1405
1406 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1407 {
1408 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1409 return TRACE_TYPE_UNHANDLED;
1410
1411 return print_one_line(iter, true);
1412 }
1413
1414 static int
1415 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1416 {
1417 /* don't output context-info for blk_classic output */
1418 if (bit == TRACE_BLK_OPT_CLASSIC) {
1419 if (set)
1420 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1421 else
1422 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1423 }
1424 return 0;
1425 }
1426
1427 static struct tracer blk_tracer __read_mostly = {
1428 .name = "blk",
1429 .init = blk_tracer_init,
1430 .reset = blk_tracer_reset,
1431 .start = blk_tracer_start,
1432 .stop = blk_tracer_stop,
1433 .print_header = blk_tracer_print_header,
1434 .print_line = blk_tracer_print_line,
1435 .flags = &blk_tracer_flags,
1436 .set_flag = blk_tracer_set_flag,
1437 };
1438
1439 static struct trace_event_functions trace_blk_event_funcs = {
1440 .trace = blk_trace_event_print,
1441 .binary = blk_trace_event_print_binary,
1442 };
1443
1444 static struct trace_event trace_blk_event = {
1445 .type = TRACE_BLK,
1446 .funcs = &trace_blk_event_funcs,
1447 };
1448
1449 static int __init init_blk_tracer(void)
1450 {
1451 if (!register_trace_event(&trace_blk_event)) {
1452 pr_warning("Warning: could not register block events\n");
1453 return 1;
1454 }
1455
1456 if (register_tracer(&blk_tracer) != 0) {
1457 pr_warning("Warning: could not register the block tracer\n");
1458 unregister_trace_event(&trace_blk_event);
1459 return 1;
1460 }
1461
1462 return 0;
1463 }
1464
1465 device_initcall(init_blk_tracer);
1466
1467 static int blk_trace_remove_queue(struct request_queue *q)
1468 {
1469 struct blk_trace *bt;
1470
1471 bt = xchg(&q->blk_trace, NULL);
1472 if (bt == NULL)
1473 return -EINVAL;
1474
1475 if (atomic_dec_and_test(&blk_probes_ref))
1476 blk_unregister_tracepoints();
1477
1478 blk_trace_free(bt);
1479 return 0;
1480 }
1481
1482 /*
1483 * Setup everything required to start tracing
1484 */
1485 static int blk_trace_setup_queue(struct request_queue *q,
1486 struct block_device *bdev)
1487 {
1488 struct blk_trace *old_bt, *bt = NULL;
1489 int ret = -ENOMEM;
1490
1491 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1492 if (!bt)
1493 return -ENOMEM;
1494
1495 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1496 if (!bt->msg_data)
1497 goto free_bt;
1498
1499 bt->dev = bdev->bd_dev;
1500 bt->act_mask = (u16)-1;
1501
1502 blk_trace_setup_lba(bt, bdev);
1503
1504 old_bt = xchg(&q->blk_trace, bt);
1505 if (old_bt != NULL) {
1506 (void)xchg(&q->blk_trace, old_bt);
1507 ret = -EBUSY;
1508 goto free_bt;
1509 }
1510
1511 if (atomic_inc_return(&blk_probes_ref) == 1)
1512 blk_register_tracepoints();
1513 return 0;
1514
1515 free_bt:
1516 blk_trace_free(bt);
1517 return ret;
1518 }
1519
1520 /*
1521 * sysfs interface to enable and configure tracing
1522 */
1523
1524 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1525 struct device_attribute *attr,
1526 char *buf);
1527 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1528 struct device_attribute *attr,
1529 const char *buf, size_t count);
1530 #define BLK_TRACE_DEVICE_ATTR(_name) \
1531 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1532 sysfs_blk_trace_attr_show, \
1533 sysfs_blk_trace_attr_store)
1534
1535 static BLK_TRACE_DEVICE_ATTR(enable);
1536 static BLK_TRACE_DEVICE_ATTR(act_mask);
1537 static BLK_TRACE_DEVICE_ATTR(pid);
1538 static BLK_TRACE_DEVICE_ATTR(start_lba);
1539 static BLK_TRACE_DEVICE_ATTR(end_lba);
1540
1541 static struct attribute *blk_trace_attrs[] = {
1542 &dev_attr_enable.attr,
1543 &dev_attr_act_mask.attr,
1544 &dev_attr_pid.attr,
1545 &dev_attr_start_lba.attr,
1546 &dev_attr_end_lba.attr,
1547 NULL
1548 };
1549
1550 struct attribute_group blk_trace_attr_group = {
1551 .name = "trace",
1552 .attrs = blk_trace_attrs,
1553 };
1554
1555 static const struct {
1556 int mask;
1557 const char *str;
1558 } mask_maps[] = {
1559 { BLK_TC_READ, "read" },
1560 { BLK_TC_WRITE, "write" },
1561 { BLK_TC_FLUSH, "flush" },
1562 { BLK_TC_SYNC, "sync" },
1563 { BLK_TC_QUEUE, "queue" },
1564 { BLK_TC_REQUEUE, "requeue" },
1565 { BLK_TC_ISSUE, "issue" },
1566 { BLK_TC_COMPLETE, "complete" },
1567 { BLK_TC_FS, "fs" },
1568 { BLK_TC_PC, "pc" },
1569 { BLK_TC_AHEAD, "ahead" },
1570 { BLK_TC_META, "meta" },
1571 { BLK_TC_DISCARD, "discard" },
1572 { BLK_TC_DRV_DATA, "drv_data" },
1573 { BLK_TC_FUA, "fua" },
1574 };
1575
1576 static int blk_trace_str2mask(const char *str)
1577 {
1578 int i;
1579 int mask = 0;
1580 char *buf, *s, *token;
1581
1582 buf = kstrdup(str, GFP_KERNEL);
1583 if (buf == NULL)
1584 return -ENOMEM;
1585 s = strstrip(buf);
1586
1587 while (1) {
1588 token = strsep(&s, ",");
1589 if (token == NULL)
1590 break;
1591
1592 if (*token == '\0')
1593 continue;
1594
1595 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1596 if (strcasecmp(token, mask_maps[i].str) == 0) {
1597 mask |= mask_maps[i].mask;
1598 break;
1599 }
1600 }
1601 if (i == ARRAY_SIZE(mask_maps)) {
1602 mask = -EINVAL;
1603 break;
1604 }
1605 }
1606 kfree(buf);
1607
1608 return mask;
1609 }
1610
1611 static ssize_t blk_trace_mask2str(char *buf, int mask)
1612 {
1613 int i;
1614 char *p = buf;
1615
1616 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1617 if (mask & mask_maps[i].mask) {
1618 p += sprintf(p, "%s%s",
1619 (p == buf) ? "" : ",", mask_maps[i].str);
1620 }
1621 }
1622 *p++ = '\n';
1623
1624 return p - buf;
1625 }
1626
1627 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1628 {
1629 if (bdev->bd_disk == NULL)
1630 return NULL;
1631
1632 return bdev_get_queue(bdev);
1633 }
1634
1635 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1636 struct device_attribute *attr,
1637 char *buf)
1638 {
1639 struct hd_struct *p = dev_to_part(dev);
1640 struct request_queue *q;
1641 struct block_device *bdev;
1642 ssize_t ret = -ENXIO;
1643
1644 bdev = bdget(part_devt(p));
1645 if (bdev == NULL)
1646 goto out;
1647
1648 q = blk_trace_get_queue(bdev);
1649 if (q == NULL)
1650 goto out_bdput;
1651
1652 mutex_lock(&bdev->bd_mutex);
1653
1654 if (attr == &dev_attr_enable) {
1655 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1656 goto out_unlock_bdev;
1657 }
1658
1659 if (q->blk_trace == NULL)
1660 ret = sprintf(buf, "disabled\n");
1661 else if (attr == &dev_attr_act_mask)
1662 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1663 else if (attr == &dev_attr_pid)
1664 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1665 else if (attr == &dev_attr_start_lba)
1666 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1667 else if (attr == &dev_attr_end_lba)
1668 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1669
1670 out_unlock_bdev:
1671 mutex_unlock(&bdev->bd_mutex);
1672 out_bdput:
1673 bdput(bdev);
1674 out:
1675 return ret;
1676 }
1677
1678 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1679 struct device_attribute *attr,
1680 const char *buf, size_t count)
1681 {
1682 struct block_device *bdev;
1683 struct request_queue *q;
1684 struct hd_struct *p;
1685 u64 value;
1686 ssize_t ret = -EINVAL;
1687
1688 if (count == 0)
1689 goto out;
1690
1691 if (attr == &dev_attr_act_mask) {
1692 if (sscanf(buf, "%llx", &value) != 1) {
1693 /* Assume it is a list of trace category names */
1694 ret = blk_trace_str2mask(buf);
1695 if (ret < 0)
1696 goto out;
1697 value = ret;
1698 }
1699 } else if (sscanf(buf, "%llu", &value) != 1)
1700 goto out;
1701
1702 ret = -ENXIO;
1703
1704 p = dev_to_part(dev);
1705 bdev = bdget(part_devt(p));
1706 if (bdev == NULL)
1707 goto out;
1708
1709 q = blk_trace_get_queue(bdev);
1710 if (q == NULL)
1711 goto out_bdput;
1712
1713 mutex_lock(&bdev->bd_mutex);
1714
1715 if (attr == &dev_attr_enable) {
1716 if (value)
1717 ret = blk_trace_setup_queue(q, bdev);
1718 else
1719 ret = blk_trace_remove_queue(q);
1720 goto out_unlock_bdev;
1721 }
1722
1723 ret = 0;
1724 if (q->blk_trace == NULL)
1725 ret = blk_trace_setup_queue(q, bdev);
1726
1727 if (ret == 0) {
1728 if (attr == &dev_attr_act_mask)
1729 q->blk_trace->act_mask = value;
1730 else if (attr == &dev_attr_pid)
1731 q->blk_trace->pid = value;
1732 else if (attr == &dev_attr_start_lba)
1733 q->blk_trace->start_lba = value;
1734 else if (attr == &dev_attr_end_lba)
1735 q->blk_trace->end_lba = value;
1736 }
1737
1738 out_unlock_bdev:
1739 mutex_unlock(&bdev->bd_mutex);
1740 out_bdput:
1741 bdput(bdev);
1742 out:
1743 return ret ? ret : count;
1744 }
1745
1746 int blk_trace_init_sysfs(struct device *dev)
1747 {
1748 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1749 }
1750
1751 void blk_trace_remove_sysfs(struct device *dev)
1752 {
1753 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1754 }
1755
1756 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1757
1758 #ifdef CONFIG_EVENT_TRACING
1759
1760 void blk_dump_cmd(char *buf, struct request *rq)
1761 {
1762 int i, end;
1763 int len = rq->cmd_len;
1764 unsigned char *cmd = rq->cmd;
1765
1766 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1767 buf[0] = '\0';
1768 return;
1769 }
1770
1771 for (end = len - 1; end >= 0; end--)
1772 if (cmd[end])
1773 break;
1774 end++;
1775
1776 for (i = 0; i < len; i++) {
1777 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1778 if (i == end && end != len - 1) {
1779 sprintf(buf, " ..");
1780 break;
1781 }
1782 }
1783 }
1784
1785 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1786 {
1787 int i = 0;
1788
1789 if (rw & REQ_FLUSH)
1790 rwbs[i++] = 'F';
1791
1792 if (rw & WRITE)
1793 rwbs[i++] = 'W';
1794 else if (rw & REQ_DISCARD)
1795 rwbs[i++] = 'D';
1796 else if (bytes)
1797 rwbs[i++] = 'R';
1798 else
1799 rwbs[i++] = 'N';
1800
1801 if (rw & REQ_FUA)
1802 rwbs[i++] = 'F';
1803 if (rw & REQ_RAHEAD)
1804 rwbs[i++] = 'A';
1805 if (rw & REQ_SYNC)
1806 rwbs[i++] = 'S';
1807 if (rw & REQ_META)
1808 rwbs[i++] = 'M';
1809 if (rw & REQ_SECURE)
1810 rwbs[i++] = 'E';
1811
1812 rwbs[i] = '\0';
1813 }
1814 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1815
1816 #endif /* CONFIG_EVENT_TRACING */
1817
Linux kernel - Deliverables
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