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kexec: get rid of duplicate check for hole_end
[deliverable/linux.git] / kernel / trace / blktrace.c
1 /*
2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
16 *
17 */
18 #include <linux/kernel.h>
19 #include <linux/blkdev.h>
20 #include <linux/blktrace_api.h>
21 #include <linux/percpu.h>
22 #include <linux/init.h>
23 #include <linux/mutex.h>
24 #include <linux/slab.h>
25 #include <linux/debugfs.h>
26 #include <linux/export.h>
27 #include <linux/time.h>
28 #include <linux/uaccess.h>
29
30 #include <trace/events/block.h>
31
32 #include "trace_output.h"
33
34 #ifdef CONFIG_BLK_DEV_IO_TRACE
35
36 static unsigned int blktrace_seq __read_mostly = 1;
37
38 static struct trace_array *blk_tr;
39 static bool blk_tracer_enabled __read_mostly;
40
41 /* Select an alternative, minimalistic output than the original one */
42 #define TRACE_BLK_OPT_CLASSIC 0x1
43
44 static struct tracer_opt blk_tracer_opts[] = {
45 /* Default disable the minimalistic output */
46 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
47 { }
48 };
49
50 static struct tracer_flags blk_tracer_flags = {
51 .val = 0,
52 .opts = blk_tracer_opts,
53 };
54
55 /* Global reference count of probes */
56 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
57
58 static void blk_register_tracepoints(void);
59 static void blk_unregister_tracepoints(void);
60
61 /*
62 * Send out a notify message.
63 */
64 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
65 const void *data, size_t len)
66 {
67 struct blk_io_trace *t;
68 struct ring_buffer_event *event = NULL;
69 struct ring_buffer *buffer = NULL;
70 int pc = 0;
71 int cpu = smp_processor_id();
72 bool blk_tracer = blk_tracer_enabled;
73
74 if (blk_tracer) {
75 buffer = blk_tr->buffer;
76 pc = preempt_count();
77 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
78 sizeof(*t) + len,
79 0, pc);
80 if (!event)
81 return;
82 t = ring_buffer_event_data(event);
83 goto record_it;
84 }
85
86 if (!bt->rchan)
87 return;
88
89 t = relay_reserve(bt->rchan, sizeof(*t) + len);
90 if (t) {
91 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
92 t->time = ktime_to_ns(ktime_get());
93 record_it:
94 t->device = bt->dev;
95 t->action = action;
96 t->pid = pid;
97 t->cpu = cpu;
98 t->pdu_len = len;
99 memcpy((void *) t + sizeof(*t), data, len);
100
101 if (blk_tracer)
102 trace_buffer_unlock_commit(buffer, event, 0, pc);
103 }
104 }
105
106 /*
107 * Send out a notify for this process, if we haven't done so since a trace
108 * started
109 */
110 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
111 {
112 tsk->btrace_seq = blktrace_seq;
113 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
114 }
115
116 static void trace_note_time(struct blk_trace *bt)
117 {
118 struct timespec now;
119 unsigned long flags;
120 u32 words[2];
121
122 getnstimeofday(&now);
123 words[0] = now.tv_sec;
124 words[1] = now.tv_nsec;
125
126 local_irq_save(flags);
127 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
128 local_irq_restore(flags);
129 }
130
131 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
132 {
133 int n;
134 va_list args;
135 unsigned long flags;
136 char *buf;
137
138 if (unlikely(bt->trace_state != Blktrace_running &&
139 !blk_tracer_enabled))
140 return;
141
142 /*
143 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
144 * message to the trace.
145 */
146 if (!(bt->act_mask & BLK_TC_NOTIFY))
147 return;
148
149 local_irq_save(flags);
150 buf = this_cpu_ptr(bt->msg_data);
151 va_start(args, fmt);
152 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
153 va_end(args);
154
155 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
156 local_irq_restore(flags);
157 }
158 EXPORT_SYMBOL_GPL(__trace_note_message);
159
160 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
161 pid_t pid)
162 {
163 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
164 return 1;
165 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
166 return 1;
167 if (bt->pid && pid != bt->pid)
168 return 1;
169
170 return 0;
171 }
172
173 /*
174 * Data direction bit lookup
175 */
176 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
177 BLK_TC_ACT(BLK_TC_WRITE) };
178
179 #define BLK_TC_RAHEAD BLK_TC_AHEAD
180
181 /* The ilog2() calls fall out because they're constant */
182 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
183 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
184
185 /*
186 * The worker for the various blk_add_trace*() types. Fills out a
187 * blk_io_trace structure and places it in a per-cpu subbuffer.
188 */
189 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
190 int rw, u32 what, int error, int pdu_len, void *pdu_data)
191 {
192 struct task_struct *tsk = current;
193 struct ring_buffer_event *event = NULL;
194 struct ring_buffer *buffer = NULL;
195 struct blk_io_trace *t;
196 unsigned long flags = 0;
197 unsigned long *sequence;
198 pid_t pid;
199 int cpu, pc = 0;
200 bool blk_tracer = blk_tracer_enabled;
201
202 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
203 return;
204
205 what |= ddir_act[rw & WRITE];
206 what |= MASK_TC_BIT(rw, SYNC);
207 what |= MASK_TC_BIT(rw, RAHEAD);
208 what |= MASK_TC_BIT(rw, META);
209 what |= MASK_TC_BIT(rw, DISCARD);
210 what |= MASK_TC_BIT(rw, FLUSH);
211 what |= MASK_TC_BIT(rw, FUA);
212
213 pid = tsk->pid;
214 if (act_log_check(bt, what, sector, pid))
215 return;
216 cpu = raw_smp_processor_id();
217
218 if (blk_tracer) {
219 tracing_record_cmdline(current);
220
221 buffer = blk_tr->buffer;
222 pc = preempt_count();
223 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
224 sizeof(*t) + pdu_len,
225 0, pc);
226 if (!event)
227 return;
228 t = ring_buffer_event_data(event);
229 goto record_it;
230 }
231
232 /*
233 * A word about the locking here - we disable interrupts to reserve
234 * some space in the relay per-cpu buffer, to prevent an irq
235 * from coming in and stepping on our toes.
236 */
237 local_irq_save(flags);
238
239 if (unlikely(tsk->btrace_seq != blktrace_seq))
240 trace_note_tsk(bt, tsk);
241
242 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
243 if (t) {
244 sequence = per_cpu_ptr(bt->sequence, cpu);
245
246 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
247 t->sequence = ++(*sequence);
248 t->time = ktime_to_ns(ktime_get());
249 record_it:
250 /*
251 * These two are not needed in ftrace as they are in the
252 * generic trace_entry, filled by tracing_generic_entry_update,
253 * but for the trace_event->bin() synthesizer benefit we do it
254 * here too.
255 */
256 t->cpu = cpu;
257 t->pid = pid;
258
259 t->sector = sector;
260 t->bytes = bytes;
261 t->action = what;
262 t->device = bt->dev;
263 t->error = error;
264 t->pdu_len = pdu_len;
265
266 if (pdu_len)
267 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
268
269 if (blk_tracer) {
270 trace_buffer_unlock_commit(buffer, event, 0, pc);
271 return;
272 }
273 }
274
275 local_irq_restore(flags);
276 }
277
278 static struct dentry *blk_tree_root;
279 static DEFINE_MUTEX(blk_tree_mutex);
280
281 static void blk_trace_free(struct blk_trace *bt)
282 {
283 debugfs_remove(bt->msg_file);
284 debugfs_remove(bt->dropped_file);
285 relay_close(bt->rchan);
286 debugfs_remove(bt->dir);
287 free_percpu(bt->sequence);
288 free_percpu(bt->msg_data);
289 kfree(bt);
290 }
291
292 static void blk_trace_cleanup(struct blk_trace *bt)
293 {
294 blk_trace_free(bt);
295 if (atomic_dec_and_test(&blk_probes_ref))
296 blk_unregister_tracepoints();
297 }
298
299 int blk_trace_remove(struct request_queue *q)
300 {
301 struct blk_trace *bt;
302
303 bt = xchg(&q->blk_trace, NULL);
304 if (!bt)
305 return -EINVAL;
306
307 if (bt->trace_state != Blktrace_running)
308 blk_trace_cleanup(bt);
309
310 return 0;
311 }
312 EXPORT_SYMBOL_GPL(blk_trace_remove);
313
314 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
315 size_t count, loff_t *ppos)
316 {
317 struct blk_trace *bt = filp->private_data;
318 char buf[16];
319
320 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
321
322 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
323 }
324
325 static const struct file_operations blk_dropped_fops = {
326 .owner = THIS_MODULE,
327 .open = simple_open,
328 .read = blk_dropped_read,
329 .llseek = default_llseek,
330 };
331
332 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
333 size_t count, loff_t *ppos)
334 {
335 char *msg;
336 struct blk_trace *bt;
337
338 if (count >= BLK_TN_MAX_MSG)
339 return -EINVAL;
340
341 msg = kmalloc(count + 1, GFP_KERNEL);
342 if (msg == NULL)
343 return -ENOMEM;
344
345 if (copy_from_user(msg, buffer, count)) {
346 kfree(msg);
347 return -EFAULT;
348 }
349
350 msg[count] = '\0';
351 bt = filp->private_data;
352 __trace_note_message(bt, "%s", msg);
353 kfree(msg);
354
355 return count;
356 }
357
358 static const struct file_operations blk_msg_fops = {
359 .owner = THIS_MODULE,
360 .open = simple_open,
361 .write = blk_msg_write,
362 .llseek = noop_llseek,
363 };
364
365 /*
366 * Keep track of how many times we encountered a full subbuffer, to aid
367 * the user space app in telling how many lost events there were.
368 */
369 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
370 void *prev_subbuf, size_t prev_padding)
371 {
372 struct blk_trace *bt;
373
374 if (!relay_buf_full(buf))
375 return 1;
376
377 bt = buf->chan->private_data;
378 atomic_inc(&bt->dropped);
379 return 0;
380 }
381
382 static int blk_remove_buf_file_callback(struct dentry *dentry)
383 {
384 debugfs_remove(dentry);
385
386 return 0;
387 }
388
389 static struct dentry *blk_create_buf_file_callback(const char *filename,
390 struct dentry *parent,
391 umode_t mode,
392 struct rchan_buf *buf,
393 int *is_global)
394 {
395 return debugfs_create_file(filename, mode, parent, buf,
396 &relay_file_operations);
397 }
398
399 static struct rchan_callbacks blk_relay_callbacks = {
400 .subbuf_start = blk_subbuf_start_callback,
401 .create_buf_file = blk_create_buf_file_callback,
402 .remove_buf_file = blk_remove_buf_file_callback,
403 };
404
405 static void blk_trace_setup_lba(struct blk_trace *bt,
406 struct block_device *bdev)
407 {
408 struct hd_struct *part = NULL;
409
410 if (bdev)
411 part = bdev->bd_part;
412
413 if (part) {
414 bt->start_lba = part->start_sect;
415 bt->end_lba = part->start_sect + part->nr_sects;
416 } else {
417 bt->start_lba = 0;
418 bt->end_lba = -1ULL;
419 }
420 }
421
422 /*
423 * Setup everything required to start tracing
424 */
425 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
426 struct block_device *bdev,
427 struct blk_user_trace_setup *buts)
428 {
429 struct blk_trace *old_bt, *bt = NULL;
430 struct dentry *dir = NULL;
431 int ret, i;
432
433 if (!buts->buf_size || !buts->buf_nr)
434 return -EINVAL;
435
436 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
437 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
438
439 /*
440 * some device names have larger paths - convert the slashes
441 * to underscores for this to work as expected
442 */
443 for (i = 0; i < strlen(buts->name); i++)
444 if (buts->name[i] == '/')
445 buts->name[i] = '_';
446
447 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
448 if (!bt)
449 return -ENOMEM;
450
451 ret = -ENOMEM;
452 bt->sequence = alloc_percpu(unsigned long);
453 if (!bt->sequence)
454 goto err;
455
456 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
457 if (!bt->msg_data)
458 goto err;
459
460 ret = -ENOENT;
461
462 mutex_lock(&blk_tree_mutex);
463 if (!blk_tree_root) {
464 blk_tree_root = debugfs_create_dir("block", NULL);
465 if (!blk_tree_root) {
466 mutex_unlock(&blk_tree_mutex);
467 goto err;
468 }
469 }
470 mutex_unlock(&blk_tree_mutex);
471
472 dir = debugfs_create_dir(buts->name, blk_tree_root);
473
474 if (!dir)
475 goto err;
476
477 bt->dir = dir;
478 bt->dev = dev;
479 atomic_set(&bt->dropped, 0);
480
481 ret = -EIO;
482 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
483 &blk_dropped_fops);
484 if (!bt->dropped_file)
485 goto err;
486
487 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
488 if (!bt->msg_file)
489 goto err;
490
491 bt->rchan = relay_open("trace", dir, buts->buf_size,
492 buts->buf_nr, &blk_relay_callbacks, bt);
493 if (!bt->rchan)
494 goto err;
495
496 bt->act_mask = buts->act_mask;
497 if (!bt->act_mask)
498 bt->act_mask = (u16) -1;
499
500 blk_trace_setup_lba(bt, bdev);
501
502 /* overwrite with user settings */
503 if (buts->start_lba)
504 bt->start_lba = buts->start_lba;
505 if (buts->end_lba)
506 bt->end_lba = buts->end_lba;
507
508 bt->pid = buts->pid;
509 bt->trace_state = Blktrace_setup;
510
511 ret = -EBUSY;
512 old_bt = xchg(&q->blk_trace, bt);
513 if (old_bt) {
514 (void) xchg(&q->blk_trace, old_bt);
515 goto err;
516 }
517
518 if (atomic_inc_return(&blk_probes_ref) == 1)
519 blk_register_tracepoints();
520
521 return 0;
522 err:
523 blk_trace_free(bt);
524 return ret;
525 }
526
527 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
528 struct block_device *bdev,
529 char __user *arg)
530 {
531 struct blk_user_trace_setup buts;
532 int ret;
533
534 ret = copy_from_user(&buts, arg, sizeof(buts));
535 if (ret)
536 return -EFAULT;
537
538 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
539 if (ret)
540 return ret;
541
542 if (copy_to_user(arg, &buts, sizeof(buts))) {
543 blk_trace_remove(q);
544 return -EFAULT;
545 }
546 return 0;
547 }
548 EXPORT_SYMBOL_GPL(blk_trace_setup);
549
550 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
551 static int compat_blk_trace_setup(struct request_queue *q, char *name,
552 dev_t dev, struct block_device *bdev,
553 char __user *arg)
554 {
555 struct blk_user_trace_setup buts;
556 struct compat_blk_user_trace_setup cbuts;
557 int ret;
558
559 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
560 return -EFAULT;
561
562 buts = (struct blk_user_trace_setup) {
563 .act_mask = cbuts.act_mask,
564 .buf_size = cbuts.buf_size,
565 .buf_nr = cbuts.buf_nr,
566 .start_lba = cbuts.start_lba,
567 .end_lba = cbuts.end_lba,
568 .pid = cbuts.pid,
569 };
570 memcpy(&buts.name, &cbuts.name, 32);
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, 32)) {
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
605 trace_note_time(bt);
606 ret = 0;
607 }
608 } else {
609 if (bt->trace_state == Blktrace_running) {
610 bt->trace_state = Blktrace_stopped;
611 relay_flush(bt->rchan);
612 ret = 0;
613 }
614 }
615
616 return ret;
617 }
618 EXPORT_SYMBOL_GPL(blk_trace_startstop);
619
620 /**
621 * blk_trace_ioctl: - handle the ioctls associated with tracing
622 * @bdev: the block device
623 * @cmd: the ioctl cmd
624 * @arg: the argument data, if any
625 *
626 **/
627 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
628 {
629 struct request_queue *q;
630 int ret, start = 0;
631 char b[BDEVNAME_SIZE];
632
633 q = bdev_get_queue(bdev);
634 if (!q)
635 return -ENXIO;
636
637 mutex_lock(&bdev->bd_mutex);
638
639 switch (cmd) {
640 case BLKTRACESETUP:
641 bdevname(bdev, b);
642 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
643 break;
644 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
645 case BLKTRACESETUP32:
646 bdevname(bdev, b);
647 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
648 break;
649 #endif
650 case BLKTRACESTART:
651 start = 1;
652 case BLKTRACESTOP:
653 ret = blk_trace_startstop(q, start);
654 break;
655 case BLKTRACETEARDOWN:
656 ret = blk_trace_remove(q);
657 break;
658 default:
659 ret = -ENOTTY;
660 break;
661 }
662
663 mutex_unlock(&bdev->bd_mutex);
664 return ret;
665 }
666
667 /**
668 * blk_trace_shutdown: - stop and cleanup trace structures
669 * @q: the request queue associated with the device
670 *
671 **/
672 void blk_trace_shutdown(struct request_queue *q)
673 {
674 if (q->blk_trace) {
675 blk_trace_startstop(q, 0);
676 blk_trace_remove(q);
677 }
678 }
679
680 /*
681 * blktrace probes
682 */
683
684 /**
685 * blk_add_trace_rq - Add a trace for a request oriented action
686 * @q: queue the io is for
687 * @rq: the source request
688 * @what: the action
689 *
690 * Description:
691 * Records an action against a request. Will log the bio offset + size.
692 *
693 **/
694 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
695 u32 what)
696 {
697 struct blk_trace *bt = q->blk_trace;
698
699 if (likely(!bt))
700 return;
701
702 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
703 what |= BLK_TC_ACT(BLK_TC_PC);
704 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
705 what, rq->errors, rq->cmd_len, rq->cmd);
706 } else {
707 what |= BLK_TC_ACT(BLK_TC_FS);
708 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
709 rq->cmd_flags, what, rq->errors, 0, NULL);
710 }
711 }
712
713 static void blk_add_trace_rq_abort(void *ignore,
714 struct request_queue *q, struct request *rq)
715 {
716 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
717 }
718
719 static void blk_add_trace_rq_insert(void *ignore,
720 struct request_queue *q, struct request *rq)
721 {
722 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
723 }
724
725 static void blk_add_trace_rq_issue(void *ignore,
726 struct request_queue *q, struct request *rq)
727 {
728 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
729 }
730
731 static void blk_add_trace_rq_requeue(void *ignore,
732 struct request_queue *q,
733 struct request *rq)
734 {
735 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
736 }
737
738 static void blk_add_trace_rq_complete(void *ignore,
739 struct request_queue *q,
740 struct request *rq)
741 {
742 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
743 }
744
745 /**
746 * blk_add_trace_bio - Add a trace for a bio oriented action
747 * @q: queue the io is for
748 * @bio: the source bio
749 * @what: the action
750 * @error: error, if any
751 *
752 * Description:
753 * Records an action against a bio. Will log the bio offset + size.
754 *
755 **/
756 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
757 u32 what, int error)
758 {
759 struct blk_trace *bt = q->blk_trace;
760
761 if (likely(!bt))
762 return;
763
764 if (!error && !bio_flagged(bio, BIO_UPTODATE))
765 error = EIO;
766
767 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
768 error, 0, NULL);
769 }
770
771 static void blk_add_trace_bio_bounce(void *ignore,
772 struct request_queue *q, struct bio *bio)
773 {
774 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
775 }
776
777 static void blk_add_trace_bio_complete(void *ignore,
778 struct request_queue *q, struct bio *bio,
779 int error)
780 {
781 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
782 }
783
784 static void blk_add_trace_bio_backmerge(void *ignore,
785 struct request_queue *q,
786 struct bio *bio)
787 {
788 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
789 }
790
791 static void blk_add_trace_bio_frontmerge(void *ignore,
792 struct request_queue *q,
793 struct bio *bio)
794 {
795 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
796 }
797
798 static void blk_add_trace_bio_queue(void *ignore,
799 struct request_queue *q, struct bio *bio)
800 {
801 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
802 }
803
804 static void blk_add_trace_getrq(void *ignore,
805 struct request_queue *q,
806 struct bio *bio, int rw)
807 {
808 if (bio)
809 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
810 else {
811 struct blk_trace *bt = q->blk_trace;
812
813 if (bt)
814 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
815 }
816 }
817
818
819 static void blk_add_trace_sleeprq(void *ignore,
820 struct request_queue *q,
821 struct bio *bio, int rw)
822 {
823 if (bio)
824 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
825 else {
826 struct blk_trace *bt = q->blk_trace;
827
828 if (bt)
829 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
830 0, 0, NULL);
831 }
832 }
833
834 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
835 {
836 struct blk_trace *bt = q->blk_trace;
837
838 if (bt)
839 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
840 }
841
842 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
843 unsigned int depth, bool explicit)
844 {
845 struct blk_trace *bt = q->blk_trace;
846
847 if (bt) {
848 __be64 rpdu = cpu_to_be64(depth);
849 u32 what;
850
851 if (explicit)
852 what = BLK_TA_UNPLUG_IO;
853 else
854 what = BLK_TA_UNPLUG_TIMER;
855
856 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
857 }
858 }
859
860 static void blk_add_trace_split(void *ignore,
861 struct request_queue *q, struct bio *bio,
862 unsigned int pdu)
863 {
864 struct blk_trace *bt = q->blk_trace;
865
866 if (bt) {
867 __be64 rpdu = cpu_to_be64(pdu);
868
869 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
870 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
871 sizeof(rpdu), &rpdu);
872 }
873 }
874
875 /**
876 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
877 * @ignore: trace callback data parameter (not used)
878 * @q: queue the io is for
879 * @bio: the source bio
880 * @dev: target device
881 * @from: source sector
882 *
883 * Description:
884 * Device mapper or raid target sometimes need to split a bio because
885 * it spans a stripe (or similar). Add a trace for that action.
886 *
887 **/
888 static void blk_add_trace_bio_remap(void *ignore,
889 struct request_queue *q, struct bio *bio,
890 dev_t dev, sector_t from)
891 {
892 struct blk_trace *bt = q->blk_trace;
893 struct blk_io_trace_remap r;
894
895 if (likely(!bt))
896 return;
897
898 r.device_from = cpu_to_be32(dev);
899 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
900 r.sector_from = cpu_to_be64(from);
901
902 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
903 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
904 sizeof(r), &r);
905 }
906
907 /**
908 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
909 * @ignore: trace callback data parameter (not used)
910 * @q: queue the io is for
911 * @rq: the source request
912 * @dev: target device
913 * @from: source sector
914 *
915 * Description:
916 * Device mapper remaps request to other devices.
917 * Add a trace for that action.
918 *
919 **/
920 static void blk_add_trace_rq_remap(void *ignore,
921 struct request_queue *q,
922 struct request *rq, dev_t dev,
923 sector_t from)
924 {
925 struct blk_trace *bt = q->blk_trace;
926 struct blk_io_trace_remap r;
927
928 if (likely(!bt))
929 return;
930
931 r.device_from = cpu_to_be32(dev);
932 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
933 r.sector_from = cpu_to_be64(from);
934
935 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
936 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
937 sizeof(r), &r);
938 }
939
940 /**
941 * blk_add_driver_data - Add binary message with driver-specific data
942 * @q: queue the io is for
943 * @rq: io request
944 * @data: driver-specific data
945 * @len: length of driver-specific data
946 *
947 * Description:
948 * Some drivers might want to write driver-specific data per request.
949 *
950 **/
951 void blk_add_driver_data(struct request_queue *q,
952 struct request *rq,
953 void *data, size_t len)
954 {
955 struct blk_trace *bt = q->blk_trace;
956
957 if (likely(!bt))
958 return;
959
960 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
961 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
962 BLK_TA_DRV_DATA, rq->errors, len, data);
963 else
964 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
965 BLK_TA_DRV_DATA, rq->errors, len, data);
966 }
967 EXPORT_SYMBOL_GPL(blk_add_driver_data);
968
969 static void blk_register_tracepoints(void)
970 {
971 int ret;
972
973 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
974 WARN_ON(ret);
975 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
976 WARN_ON(ret);
977 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
978 WARN_ON(ret);
979 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
980 WARN_ON(ret);
981 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
982 WARN_ON(ret);
983 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
984 WARN_ON(ret);
985 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
986 WARN_ON(ret);
987 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
988 WARN_ON(ret);
989 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
990 WARN_ON(ret);
991 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
992 WARN_ON(ret);
993 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
994 WARN_ON(ret);
995 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_split(blk_add_trace_split, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1006 WARN_ON(ret);
1007 }
1008
1009 static void blk_unregister_tracepoints(void)
1010 {
1011 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1012 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1013 unregister_trace_block_split(blk_add_trace_split, NULL);
1014 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1015 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1016 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1017 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1018 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1019 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1020 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1021 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1022 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1023 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1024 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1025 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1026 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1027 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1028
1029 tracepoint_synchronize_unregister();
1030 }
1031
1032 /*
1033 * struct blk_io_tracer formatting routines
1034 */
1035
1036 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1037 {
1038 int i = 0;
1039 int tc = t->action >> BLK_TC_SHIFT;
1040
1041 if (t->action == BLK_TN_MESSAGE) {
1042 rwbs[i++] = 'N';
1043 goto out;
1044 }
1045
1046 if (tc & BLK_TC_FLUSH)
1047 rwbs[i++] = 'F';
1048
1049 if (tc & BLK_TC_DISCARD)
1050 rwbs[i++] = 'D';
1051 else if (tc & BLK_TC_WRITE)
1052 rwbs[i++] = 'W';
1053 else if (t->bytes)
1054 rwbs[i++] = 'R';
1055 else
1056 rwbs[i++] = 'N';
1057
1058 if (tc & BLK_TC_FUA)
1059 rwbs[i++] = 'F';
1060 if (tc & BLK_TC_AHEAD)
1061 rwbs[i++] = 'A';
1062 if (tc & BLK_TC_SYNC)
1063 rwbs[i++] = 'S';
1064 if (tc & BLK_TC_META)
1065 rwbs[i++] = 'M';
1066 out:
1067 rwbs[i] = '\0';
1068 }
1069
1070 static inline
1071 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1072 {
1073 return (const struct blk_io_trace *)ent;
1074 }
1075
1076 static inline const void *pdu_start(const struct trace_entry *ent)
1077 {
1078 return te_blk_io_trace(ent) + 1;
1079 }
1080
1081 static inline u32 t_action(const struct trace_entry *ent)
1082 {
1083 return te_blk_io_trace(ent)->action;
1084 }
1085
1086 static inline u32 t_bytes(const struct trace_entry *ent)
1087 {
1088 return te_blk_io_trace(ent)->bytes;
1089 }
1090
1091 static inline u32 t_sec(const struct trace_entry *ent)
1092 {
1093 return te_blk_io_trace(ent)->bytes >> 9;
1094 }
1095
1096 static inline unsigned long long t_sector(const struct trace_entry *ent)
1097 {
1098 return te_blk_io_trace(ent)->sector;
1099 }
1100
1101 static inline __u16 t_error(const struct trace_entry *ent)
1102 {
1103 return te_blk_io_trace(ent)->error;
1104 }
1105
1106 static __u64 get_pdu_int(const struct trace_entry *ent)
1107 {
1108 const __u64 *val = pdu_start(ent);
1109 return be64_to_cpu(*val);
1110 }
1111
1112 static void get_pdu_remap(const struct trace_entry *ent,
1113 struct blk_io_trace_remap *r)
1114 {
1115 const struct blk_io_trace_remap *__r = pdu_start(ent);
1116 __u64 sector_from = __r->sector_from;
1117
1118 r->device_from = be32_to_cpu(__r->device_from);
1119 r->device_to = be32_to_cpu(__r->device_to);
1120 r->sector_from = be64_to_cpu(sector_from);
1121 }
1122
1123 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1124
1125 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1126 {
1127 char rwbs[RWBS_LEN];
1128 unsigned long long ts = iter->ts;
1129 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1130 unsigned secs = (unsigned long)ts;
1131 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1132
1133 fill_rwbs(rwbs, t);
1134
1135 return trace_seq_printf(&iter->seq,
1136 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1137 MAJOR(t->device), MINOR(t->device), iter->cpu,
1138 secs, nsec_rem, iter->ent->pid, act, rwbs);
1139 }
1140
1141 static int blk_log_action(struct trace_iterator *iter, const char *act)
1142 {
1143 char rwbs[RWBS_LEN];
1144 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1145
1146 fill_rwbs(rwbs, t);
1147 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1148 MAJOR(t->device), MINOR(t->device), act, rwbs);
1149 }
1150
1151 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1152 {
1153 const unsigned char *pdu_buf;
1154 int pdu_len;
1155 int i, end, ret;
1156
1157 pdu_buf = pdu_start(ent);
1158 pdu_len = te_blk_io_trace(ent)->pdu_len;
1159
1160 if (!pdu_len)
1161 return 1;
1162
1163 /* find the last zero that needs to be printed */
1164 for (end = pdu_len - 1; end >= 0; end--)
1165 if (pdu_buf[end])
1166 break;
1167 end++;
1168
1169 if (!trace_seq_putc(s, '('))
1170 return 0;
1171
1172 for (i = 0; i < pdu_len; i++) {
1173
1174 ret = trace_seq_printf(s, "%s%02x",
1175 i == 0 ? "" : " ", pdu_buf[i]);
1176 if (!ret)
1177 return ret;
1178
1179 /*
1180 * stop when the rest is just zeroes and indicate so
1181 * with a ".." appended
1182 */
1183 if (i == end && end != pdu_len - 1)
1184 return trace_seq_puts(s, " ..) ");
1185 }
1186
1187 return trace_seq_puts(s, ") ");
1188 }
1189
1190 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1191 {
1192 char cmd[TASK_COMM_LEN];
1193
1194 trace_find_cmdline(ent->pid, cmd);
1195
1196 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1197 int ret;
1198
1199 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1200 if (!ret)
1201 return 0;
1202 ret = blk_log_dump_pdu(s, ent);
1203 if (!ret)
1204 return 0;
1205 return trace_seq_printf(s, "[%s]\n", cmd);
1206 } else {
1207 if (t_sec(ent))
1208 return trace_seq_printf(s, "%llu + %u [%s]\n",
1209 t_sector(ent), t_sec(ent), cmd);
1210 return trace_seq_printf(s, "[%s]\n", cmd);
1211 }
1212 }
1213
1214 static int blk_log_with_error(struct trace_seq *s,
1215 const struct trace_entry *ent)
1216 {
1217 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1218 int ret;
1219
1220 ret = blk_log_dump_pdu(s, ent);
1221 if (ret)
1222 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1223 return 0;
1224 } else {
1225 if (t_sec(ent))
1226 return trace_seq_printf(s, "%llu + %u [%d]\n",
1227 t_sector(ent),
1228 t_sec(ent), t_error(ent));
1229 return trace_seq_printf(s, "%llu [%d]\n",
1230 t_sector(ent), t_error(ent));
1231 }
1232 }
1233
1234 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1235 {
1236 struct blk_io_trace_remap r = { .device_from = 0, };
1237
1238 get_pdu_remap(ent, &r);
1239 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1240 t_sector(ent), t_sec(ent),
1241 MAJOR(r.device_from), MINOR(r.device_from),
1242 (unsigned long long)r.sector_from);
1243 }
1244
1245 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1246 {
1247 char cmd[TASK_COMM_LEN];
1248
1249 trace_find_cmdline(ent->pid, cmd);
1250
1251 return trace_seq_printf(s, "[%s]\n", cmd);
1252 }
1253
1254 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1255 {
1256 char cmd[TASK_COMM_LEN];
1257
1258 trace_find_cmdline(ent->pid, cmd);
1259
1260 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1261 }
1262
1263 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1264 {
1265 char cmd[TASK_COMM_LEN];
1266
1267 trace_find_cmdline(ent->pid, cmd);
1268
1269 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1270 get_pdu_int(ent), cmd);
1271 }
1272
1273 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1274 {
1275 int ret;
1276 const struct blk_io_trace *t = te_blk_io_trace(ent);
1277
1278 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1279 if (ret)
1280 return trace_seq_putc(s, '\n');
1281 return ret;
1282 }
1283
1284 /*
1285 * struct tracer operations
1286 */
1287
1288 static void blk_tracer_print_header(struct seq_file *m)
1289 {
1290 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1291 return;
1292 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1293 "# | | | | | |\n");
1294 }
1295
1296 static void blk_tracer_start(struct trace_array *tr)
1297 {
1298 blk_tracer_enabled = true;
1299 }
1300
1301 static int blk_tracer_init(struct trace_array *tr)
1302 {
1303 blk_tr = tr;
1304 blk_tracer_start(tr);
1305 return 0;
1306 }
1307
1308 static void blk_tracer_stop(struct trace_array *tr)
1309 {
1310 blk_tracer_enabled = false;
1311 }
1312
1313 static void blk_tracer_reset(struct trace_array *tr)
1314 {
1315 blk_tracer_stop(tr);
1316 }
1317
1318 static const struct {
1319 const char *act[2];
1320 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1321 } what2act[] = {
1322 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1323 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1324 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1325 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1326 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1327 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1328 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1329 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1330 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1331 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1332 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1333 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1334 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1335 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1336 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1337 };
1338
1339 static enum print_line_t print_one_line(struct trace_iterator *iter,
1340 bool classic)
1341 {
1342 struct trace_seq *s = &iter->seq;
1343 const struct blk_io_trace *t;
1344 u16 what;
1345 int ret;
1346 bool long_act;
1347 blk_log_action_t *log_action;
1348
1349 t = te_blk_io_trace(iter->ent);
1350 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1351 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1352 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1353
1354 if (t->action == BLK_TN_MESSAGE) {
1355 ret = log_action(iter, long_act ? "message" : "m");
1356 if (ret)
1357 ret = blk_log_msg(s, iter->ent);
1358 goto out;
1359 }
1360
1361 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1362 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1363 else {
1364 ret = log_action(iter, what2act[what].act[long_act]);
1365 if (ret)
1366 ret = what2act[what].print(s, iter->ent);
1367 }
1368 out:
1369 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1370 }
1371
1372 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1373 int flags, struct trace_event *event)
1374 {
1375 return print_one_line(iter, false);
1376 }
1377
1378 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1379 {
1380 struct trace_seq *s = &iter->seq;
1381 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1382 const int offset = offsetof(struct blk_io_trace, sector);
1383 struct blk_io_trace old = {
1384 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1385 .time = iter->ts,
1386 };
1387
1388 if (!trace_seq_putmem(s, &old, offset))
1389 return 0;
1390 return trace_seq_putmem(s, &t->sector,
1391 sizeof(old) - offset + t->pdu_len);
1392 }
1393
1394 static enum print_line_t
1395 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1396 struct trace_event *event)
1397 {
1398 return blk_trace_synthesize_old_trace(iter) ?
1399 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1400 }
1401
1402 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1403 {
1404 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1405 return TRACE_TYPE_UNHANDLED;
1406
1407 return print_one_line(iter, true);
1408 }
1409
1410 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1411 {
1412 /* don't output context-info for blk_classic output */
1413 if (bit == TRACE_BLK_OPT_CLASSIC) {
1414 if (set)
1415 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1416 else
1417 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1418 }
1419 return 0;
1420 }
1421
1422 static struct tracer blk_tracer __read_mostly = {
1423 .name = "blk",
1424 .init = blk_tracer_init,
1425 .reset = blk_tracer_reset,
1426 .start = blk_tracer_start,
1427 .stop = blk_tracer_stop,
1428 .print_header = blk_tracer_print_header,
1429 .print_line = blk_tracer_print_line,
1430 .flags = &blk_tracer_flags,
1431 .set_flag = blk_tracer_set_flag,
1432 };
1433
1434 static struct trace_event_functions trace_blk_event_funcs = {
1435 .trace = blk_trace_event_print,
1436 .binary = blk_trace_event_print_binary,
1437 };
1438
1439 static struct trace_event trace_blk_event = {
1440 .type = TRACE_BLK,
1441 .funcs = &trace_blk_event_funcs,
1442 };
1443
1444 static int __init init_blk_tracer(void)
1445 {
1446 if (!register_ftrace_event(&trace_blk_event)) {
1447 pr_warning("Warning: could not register block events\n");
1448 return 1;
1449 }
1450
1451 if (register_tracer(&blk_tracer) != 0) {
1452 pr_warning("Warning: could not register the block tracer\n");
1453 unregister_ftrace_event(&trace_blk_event);
1454 return 1;
1455 }
1456
1457 return 0;
1458 }
1459
1460 device_initcall(init_blk_tracer);
1461
1462 static int blk_trace_remove_queue(struct request_queue *q)
1463 {
1464 struct blk_trace *bt;
1465
1466 bt = xchg(&q->blk_trace, NULL);
1467 if (bt == NULL)
1468 return -EINVAL;
1469
1470 if (atomic_dec_and_test(&blk_probes_ref))
1471 blk_unregister_tracepoints();
1472
1473 blk_trace_free(bt);
1474 return 0;
1475 }
1476
1477 /*
1478 * Setup everything required to start tracing
1479 */
1480 static int blk_trace_setup_queue(struct request_queue *q,
1481 struct block_device *bdev)
1482 {
1483 struct blk_trace *old_bt, *bt = NULL;
1484 int ret = -ENOMEM;
1485
1486 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1487 if (!bt)
1488 return -ENOMEM;
1489
1490 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1491 if (!bt->msg_data)
1492 goto free_bt;
1493
1494 bt->dev = bdev->bd_dev;
1495 bt->act_mask = (u16)-1;
1496
1497 blk_trace_setup_lba(bt, bdev);
1498
1499 old_bt = xchg(&q->blk_trace, bt);
1500 if (old_bt != NULL) {
1501 (void)xchg(&q->blk_trace, old_bt);
1502 ret = -EBUSY;
1503 goto free_bt;
1504 }
1505
1506 if (atomic_inc_return(&blk_probes_ref) == 1)
1507 blk_register_tracepoints();
1508 return 0;
1509
1510 free_bt:
1511 blk_trace_free(bt);
1512 return ret;
1513 }
1514
1515 /*
1516 * sysfs interface to enable and configure tracing
1517 */
1518
1519 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1520 struct device_attribute *attr,
1521 char *buf);
1522 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1523 struct device_attribute *attr,
1524 const char *buf, size_t count);
1525 #define BLK_TRACE_DEVICE_ATTR(_name) \
1526 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1527 sysfs_blk_trace_attr_show, \
1528 sysfs_blk_trace_attr_store)
1529
1530 static BLK_TRACE_DEVICE_ATTR(enable);
1531 static BLK_TRACE_DEVICE_ATTR(act_mask);
1532 static BLK_TRACE_DEVICE_ATTR(pid);
1533 static BLK_TRACE_DEVICE_ATTR(start_lba);
1534 static BLK_TRACE_DEVICE_ATTR(end_lba);
1535
1536 static struct attribute *blk_trace_attrs[] = {
1537 &dev_attr_enable.attr,
1538 &dev_attr_act_mask.attr,
1539 &dev_attr_pid.attr,
1540 &dev_attr_start_lba.attr,
1541 &dev_attr_end_lba.attr,
1542 NULL
1543 };
1544
1545 struct attribute_group blk_trace_attr_group = {
1546 .name = "trace",
1547 .attrs = blk_trace_attrs,
1548 };
1549
1550 static const struct {
1551 int mask;
1552 const char *str;
1553 } mask_maps[] = {
1554 { BLK_TC_READ, "read" },
1555 { BLK_TC_WRITE, "write" },
1556 { BLK_TC_FLUSH, "flush" },
1557 { BLK_TC_SYNC, "sync" },
1558 { BLK_TC_QUEUE, "queue" },
1559 { BLK_TC_REQUEUE, "requeue" },
1560 { BLK_TC_ISSUE, "issue" },
1561 { BLK_TC_COMPLETE, "complete" },
1562 { BLK_TC_FS, "fs" },
1563 { BLK_TC_PC, "pc" },
1564 { BLK_TC_AHEAD, "ahead" },
1565 { BLK_TC_META, "meta" },
1566 { BLK_TC_DISCARD, "discard" },
1567 { BLK_TC_DRV_DATA, "drv_data" },
1568 { BLK_TC_FUA, "fua" },
1569 };
1570
1571 static int blk_trace_str2mask(const char *str)
1572 {
1573 int i;
1574 int mask = 0;
1575 char *buf, *s, *token;
1576
1577 buf = kstrdup(str, GFP_KERNEL);
1578 if (buf == NULL)
1579 return -ENOMEM;
1580 s = strstrip(buf);
1581
1582 while (1) {
1583 token = strsep(&s, ",");
1584 if (token == NULL)
1585 break;
1586
1587 if (*token == '\0')
1588 continue;
1589
1590 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1591 if (strcasecmp(token, mask_maps[i].str) == 0) {
1592 mask |= mask_maps[i].mask;
1593 break;
1594 }
1595 }
1596 if (i == ARRAY_SIZE(mask_maps)) {
1597 mask = -EINVAL;
1598 break;
1599 }
1600 }
1601 kfree(buf);
1602
1603 return mask;
1604 }
1605
1606 static ssize_t blk_trace_mask2str(char *buf, int mask)
1607 {
1608 int i;
1609 char *p = buf;
1610
1611 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1612 if (mask & mask_maps[i].mask) {
1613 p += sprintf(p, "%s%s",
1614 (p == buf) ? "" : ",", mask_maps[i].str);
1615 }
1616 }
1617 *p++ = '\n';
1618
1619 return p - buf;
1620 }
1621
1622 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1623 {
1624 if (bdev->bd_disk == NULL)
1625 return NULL;
1626
1627 return bdev_get_queue(bdev);
1628 }
1629
1630 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1631 struct device_attribute *attr,
1632 char *buf)
1633 {
1634 struct hd_struct *p = dev_to_part(dev);
1635 struct request_queue *q;
1636 struct block_device *bdev;
1637 ssize_t ret = -ENXIO;
1638
1639 bdev = bdget(part_devt(p));
1640 if (bdev == NULL)
1641 goto out;
1642
1643 q = blk_trace_get_queue(bdev);
1644 if (q == NULL)
1645 goto out_bdput;
1646
1647 mutex_lock(&bdev->bd_mutex);
1648
1649 if (attr == &dev_attr_enable) {
1650 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1651 goto out_unlock_bdev;
1652 }
1653
1654 if (q->blk_trace == NULL)
1655 ret = sprintf(buf, "disabled\n");
1656 else if (attr == &dev_attr_act_mask)
1657 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1658 else if (attr == &dev_attr_pid)
1659 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1660 else if (attr == &dev_attr_start_lba)
1661 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1662 else if (attr == &dev_attr_end_lba)
1663 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1664
1665 out_unlock_bdev:
1666 mutex_unlock(&bdev->bd_mutex);
1667 out_bdput:
1668 bdput(bdev);
1669 out:
1670 return ret;
1671 }
1672
1673 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1674 struct device_attribute *attr,
1675 const char *buf, size_t count)
1676 {
1677 struct block_device *bdev;
1678 struct request_queue *q;
1679 struct hd_struct *p;
1680 u64 value;
1681 ssize_t ret = -EINVAL;
1682
1683 if (count == 0)
1684 goto out;
1685
1686 if (attr == &dev_attr_act_mask) {
1687 if (sscanf(buf, "%llx", &value) != 1) {
1688 /* Assume it is a list of trace category names */
1689 ret = blk_trace_str2mask(buf);
1690 if (ret < 0)
1691 goto out;
1692 value = ret;
1693 }
1694 } else if (sscanf(buf, "%llu", &value) != 1)
1695 goto out;
1696
1697 ret = -ENXIO;
1698
1699 p = dev_to_part(dev);
1700 bdev = bdget(part_devt(p));
1701 if (bdev == NULL)
1702 goto out;
1703
1704 q = blk_trace_get_queue(bdev);
1705 if (q == NULL)
1706 goto out_bdput;
1707
1708 mutex_lock(&bdev->bd_mutex);
1709
1710 if (attr == &dev_attr_enable) {
1711 if (value)
1712 ret = blk_trace_setup_queue(q, bdev);
1713 else
1714 ret = blk_trace_remove_queue(q);
1715 goto out_unlock_bdev;
1716 }
1717
1718 ret = 0;
1719 if (q->blk_trace == NULL)
1720 ret = blk_trace_setup_queue(q, bdev);
1721
1722 if (ret == 0) {
1723 if (attr == &dev_attr_act_mask)
1724 q->blk_trace->act_mask = value;
1725 else if (attr == &dev_attr_pid)
1726 q->blk_trace->pid = value;
1727 else if (attr == &dev_attr_start_lba)
1728 q->blk_trace->start_lba = value;
1729 else if (attr == &dev_attr_end_lba)
1730 q->blk_trace->end_lba = value;
1731 }
1732
1733 out_unlock_bdev:
1734 mutex_unlock(&bdev->bd_mutex);
1735 out_bdput:
1736 bdput(bdev);
1737 out:
1738 return ret ? ret : count;
1739 }
1740
1741 int blk_trace_init_sysfs(struct device *dev)
1742 {
1743 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1744 }
1745
1746 void blk_trace_remove_sysfs(struct device *dev)
1747 {
1748 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1749 }
1750
1751 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1752
1753 #ifdef CONFIG_EVENT_TRACING
1754
1755 void blk_dump_cmd(char *buf, struct request *rq)
1756 {
1757 int i, end;
1758 int len = rq->cmd_len;
1759 unsigned char *cmd = rq->cmd;
1760
1761 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1762 buf[0] = '\0';
1763 return;
1764 }
1765
1766 for (end = len - 1; end >= 0; end--)
1767 if (cmd[end])
1768 break;
1769 end++;
1770
1771 for (i = 0; i < len; i++) {
1772 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1773 if (i == end && end != len - 1) {
1774 sprintf(buf, " ..");
1775 break;
1776 }
1777 }
1778 }
1779
1780 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1781 {
1782 int i = 0;
1783
1784 if (rw & REQ_FLUSH)
1785 rwbs[i++] = 'F';
1786
1787 if (rw & WRITE)
1788 rwbs[i++] = 'W';
1789 else if (rw & REQ_DISCARD)
1790 rwbs[i++] = 'D';
1791 else if (bytes)
1792 rwbs[i++] = 'R';
1793 else
1794 rwbs[i++] = 'N';
1795
1796 if (rw & REQ_FUA)
1797 rwbs[i++] = 'F';
1798 if (rw & REQ_RAHEAD)
1799 rwbs[i++] = 'A';
1800 if (rw & REQ_SYNC)
1801 rwbs[i++] = 'S';
1802 if (rw & REQ_META)
1803 rwbs[i++] = 'M';
1804 if (rw & REQ_SECURE)
1805 rwbs[i++] = 'E';
1806
1807 rwbs[i] = '\0';
1808 }
1809
1810 #endif /* CONFIG_EVENT_TRACING */
1811
Linux kernel - Deliverables
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