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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph...
[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 struct blk_trace *bt = q->blk_trace;
743
744 /* if control ever passes through here, it's a request based driver */
745 if (unlikely(bt && !bt->rq_based))
746 bt->rq_based = true;
747
748 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
749 }
750
751 /**
752 * blk_add_trace_bio - Add a trace for a bio oriented action
753 * @q: queue the io is for
754 * @bio: the source bio
755 * @what: the action
756 * @error: error, if any
757 *
758 * Description:
759 * Records an action against a bio. Will log the bio offset + size.
760 *
761 **/
762 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
763 u32 what, int error)
764 {
765 struct blk_trace *bt = q->blk_trace;
766
767 if (likely(!bt))
768 return;
769
770 if (!error && !bio_flagged(bio, BIO_UPTODATE))
771 error = EIO;
772
773 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
774 error, 0, NULL);
775 }
776
777 static void blk_add_trace_bio_bounce(void *ignore,
778 struct request_queue *q, struct bio *bio)
779 {
780 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
781 }
782
783 static void blk_add_trace_bio_complete(void *ignore, struct bio *bio, int error)
784 {
785 struct request_queue *q;
786 struct blk_trace *bt;
787
788 if (!bio->bi_bdev)
789 return;
790
791 q = bdev_get_queue(bio->bi_bdev);
792 bt = q->blk_trace;
793
794 /*
795 * Request based drivers will generate both rq and bio completions.
796 * Ignore bio ones.
797 */
798 if (likely(!bt) || bt->rq_based)
799 return;
800
801 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
802 }
803
804 static void blk_add_trace_bio_backmerge(void *ignore,
805 struct request_queue *q,
806 struct request *rq,
807 struct bio *bio)
808 {
809 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
810 }
811
812 static void blk_add_trace_bio_frontmerge(void *ignore,
813 struct request_queue *q,
814 struct request *rq,
815 struct bio *bio)
816 {
817 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
818 }
819
820 static void blk_add_trace_bio_queue(void *ignore,
821 struct request_queue *q, struct bio *bio)
822 {
823 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
824 }
825
826 static void blk_add_trace_getrq(void *ignore,
827 struct request_queue *q,
828 struct bio *bio, int rw)
829 {
830 if (bio)
831 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
832 else {
833 struct blk_trace *bt = q->blk_trace;
834
835 if (bt)
836 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
837 }
838 }
839
840
841 static void blk_add_trace_sleeprq(void *ignore,
842 struct request_queue *q,
843 struct bio *bio, int rw)
844 {
845 if (bio)
846 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
847 else {
848 struct blk_trace *bt = q->blk_trace;
849
850 if (bt)
851 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
852 0, 0, NULL);
853 }
854 }
855
856 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
857 {
858 struct blk_trace *bt = q->blk_trace;
859
860 if (bt)
861 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
862 }
863
864 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
865 unsigned int depth, bool explicit)
866 {
867 struct blk_trace *bt = q->blk_trace;
868
869 if (bt) {
870 __be64 rpdu = cpu_to_be64(depth);
871 u32 what;
872
873 if (explicit)
874 what = BLK_TA_UNPLUG_IO;
875 else
876 what = BLK_TA_UNPLUG_TIMER;
877
878 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
879 }
880 }
881
882 static void blk_add_trace_split(void *ignore,
883 struct request_queue *q, struct bio *bio,
884 unsigned int pdu)
885 {
886 struct blk_trace *bt = q->blk_trace;
887
888 if (bt) {
889 __be64 rpdu = cpu_to_be64(pdu);
890
891 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
892 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
893 sizeof(rpdu), &rpdu);
894 }
895 }
896
897 /**
898 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
899 * @ignore: trace callback data parameter (not used)
900 * @q: queue the io is for
901 * @bio: the source bio
902 * @dev: target device
903 * @from: source sector
904 *
905 * Description:
906 * Device mapper or raid target sometimes need to split a bio because
907 * it spans a stripe (or similar). Add a trace for that action.
908 *
909 **/
910 static void blk_add_trace_bio_remap(void *ignore,
911 struct request_queue *q, struct bio *bio,
912 dev_t dev, sector_t from)
913 {
914 struct blk_trace *bt = q->blk_trace;
915 struct blk_io_trace_remap r;
916
917 if (likely(!bt))
918 return;
919
920 r.device_from = cpu_to_be32(dev);
921 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
922 r.sector_from = cpu_to_be64(from);
923
924 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
925 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
926 sizeof(r), &r);
927 }
928
929 /**
930 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
931 * @ignore: trace callback data parameter (not used)
932 * @q: queue the io is for
933 * @rq: the source request
934 * @dev: target device
935 * @from: source sector
936 *
937 * Description:
938 * Device mapper remaps request to other devices.
939 * Add a trace for that action.
940 *
941 **/
942 static void blk_add_trace_rq_remap(void *ignore,
943 struct request_queue *q,
944 struct request *rq, dev_t dev,
945 sector_t from)
946 {
947 struct blk_trace *bt = q->blk_trace;
948 struct blk_io_trace_remap r;
949
950 if (likely(!bt))
951 return;
952
953 r.device_from = cpu_to_be32(dev);
954 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
955 r.sector_from = cpu_to_be64(from);
956
957 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
958 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
959 sizeof(r), &r);
960 }
961
962 /**
963 * blk_add_driver_data - Add binary message with driver-specific data
964 * @q: queue the io is for
965 * @rq: io request
966 * @data: driver-specific data
967 * @len: length of driver-specific data
968 *
969 * Description:
970 * Some drivers might want to write driver-specific data per request.
971 *
972 **/
973 void blk_add_driver_data(struct request_queue *q,
974 struct request *rq,
975 void *data, size_t len)
976 {
977 struct blk_trace *bt = q->blk_trace;
978
979 if (likely(!bt))
980 return;
981
982 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
983 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
984 BLK_TA_DRV_DATA, rq->errors, len, data);
985 else
986 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
987 BLK_TA_DRV_DATA, rq->errors, len, data);
988 }
989 EXPORT_SYMBOL_GPL(blk_add_driver_data);
990
991 static void blk_register_tracepoints(void)
992 {
993 int ret;
994
995 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1006 WARN_ON(ret);
1007 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1008 WARN_ON(ret);
1009 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1010 WARN_ON(ret);
1011 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1012 WARN_ON(ret);
1013 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1014 WARN_ON(ret);
1015 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1016 WARN_ON(ret);
1017 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1018 WARN_ON(ret);
1019 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1020 WARN_ON(ret);
1021 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1022 WARN_ON(ret);
1023 ret = register_trace_block_split(blk_add_trace_split, NULL);
1024 WARN_ON(ret);
1025 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1026 WARN_ON(ret);
1027 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1028 WARN_ON(ret);
1029 }
1030
1031 static void blk_unregister_tracepoints(void)
1032 {
1033 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1034 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1035 unregister_trace_block_split(blk_add_trace_split, NULL);
1036 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1037 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1038 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1039 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1040 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1041 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1042 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1043 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1044 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1045 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1046 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1047 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1048 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1049 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1050
1051 tracepoint_synchronize_unregister();
1052 }
1053
1054 /*
1055 * struct blk_io_tracer formatting routines
1056 */
1057
1058 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1059 {
1060 int i = 0;
1061 int tc = t->action >> BLK_TC_SHIFT;
1062
1063 if (t->action == BLK_TN_MESSAGE) {
1064 rwbs[i++] = 'N';
1065 goto out;
1066 }
1067
1068 if (tc & BLK_TC_FLUSH)
1069 rwbs[i++] = 'F';
1070
1071 if (tc & BLK_TC_DISCARD)
1072 rwbs[i++] = 'D';
1073 else if (tc & BLK_TC_WRITE)
1074 rwbs[i++] = 'W';
1075 else if (t->bytes)
1076 rwbs[i++] = 'R';
1077 else
1078 rwbs[i++] = 'N';
1079
1080 if (tc & BLK_TC_FUA)
1081 rwbs[i++] = 'F';
1082 if (tc & BLK_TC_AHEAD)
1083 rwbs[i++] = 'A';
1084 if (tc & BLK_TC_SYNC)
1085 rwbs[i++] = 'S';
1086 if (tc & BLK_TC_META)
1087 rwbs[i++] = 'M';
1088 out:
1089 rwbs[i] = '\0';
1090 }
1091
1092 static inline
1093 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1094 {
1095 return (const struct blk_io_trace *)ent;
1096 }
1097
1098 static inline const void *pdu_start(const struct trace_entry *ent)
1099 {
1100 return te_blk_io_trace(ent) + 1;
1101 }
1102
1103 static inline u32 t_action(const struct trace_entry *ent)
1104 {
1105 return te_blk_io_trace(ent)->action;
1106 }
1107
1108 static inline u32 t_bytes(const struct trace_entry *ent)
1109 {
1110 return te_blk_io_trace(ent)->bytes;
1111 }
1112
1113 static inline u32 t_sec(const struct trace_entry *ent)
1114 {
1115 return te_blk_io_trace(ent)->bytes >> 9;
1116 }
1117
1118 static inline unsigned long long t_sector(const struct trace_entry *ent)
1119 {
1120 return te_blk_io_trace(ent)->sector;
1121 }
1122
1123 static inline __u16 t_error(const struct trace_entry *ent)
1124 {
1125 return te_blk_io_trace(ent)->error;
1126 }
1127
1128 static __u64 get_pdu_int(const struct trace_entry *ent)
1129 {
1130 const __u64 *val = pdu_start(ent);
1131 return be64_to_cpu(*val);
1132 }
1133
1134 static void get_pdu_remap(const struct trace_entry *ent,
1135 struct blk_io_trace_remap *r)
1136 {
1137 const struct blk_io_trace_remap *__r = pdu_start(ent);
1138 __u64 sector_from = __r->sector_from;
1139
1140 r->device_from = be32_to_cpu(__r->device_from);
1141 r->device_to = be32_to_cpu(__r->device_to);
1142 r->sector_from = be64_to_cpu(sector_from);
1143 }
1144
1145 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1146
1147 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1148 {
1149 char rwbs[RWBS_LEN];
1150 unsigned long long ts = iter->ts;
1151 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1152 unsigned secs = (unsigned long)ts;
1153 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1154
1155 fill_rwbs(rwbs, t);
1156
1157 return trace_seq_printf(&iter->seq,
1158 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1159 MAJOR(t->device), MINOR(t->device), iter->cpu,
1160 secs, nsec_rem, iter->ent->pid, act, rwbs);
1161 }
1162
1163 static int blk_log_action(struct trace_iterator *iter, const char *act)
1164 {
1165 char rwbs[RWBS_LEN];
1166 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1167
1168 fill_rwbs(rwbs, t);
1169 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1170 MAJOR(t->device), MINOR(t->device), act, rwbs);
1171 }
1172
1173 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1174 {
1175 const unsigned char *pdu_buf;
1176 int pdu_len;
1177 int i, end, ret;
1178
1179 pdu_buf = pdu_start(ent);
1180 pdu_len = te_blk_io_trace(ent)->pdu_len;
1181
1182 if (!pdu_len)
1183 return 1;
1184
1185 /* find the last zero that needs to be printed */
1186 for (end = pdu_len - 1; end >= 0; end--)
1187 if (pdu_buf[end])
1188 break;
1189 end++;
1190
1191 if (!trace_seq_putc(s, '('))
1192 return 0;
1193
1194 for (i = 0; i < pdu_len; i++) {
1195
1196 ret = trace_seq_printf(s, "%s%02x",
1197 i == 0 ? "" : " ", pdu_buf[i]);
1198 if (!ret)
1199 return ret;
1200
1201 /*
1202 * stop when the rest is just zeroes and indicate so
1203 * with a ".." appended
1204 */
1205 if (i == end && end != pdu_len - 1)
1206 return trace_seq_puts(s, " ..) ");
1207 }
1208
1209 return trace_seq_puts(s, ") ");
1210 }
1211
1212 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1213 {
1214 char cmd[TASK_COMM_LEN];
1215
1216 trace_find_cmdline(ent->pid, cmd);
1217
1218 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1219 int ret;
1220
1221 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1222 if (!ret)
1223 return 0;
1224 ret = blk_log_dump_pdu(s, ent);
1225 if (!ret)
1226 return 0;
1227 return trace_seq_printf(s, "[%s]\n", cmd);
1228 } else {
1229 if (t_sec(ent))
1230 return trace_seq_printf(s, "%llu + %u [%s]\n",
1231 t_sector(ent), t_sec(ent), cmd);
1232 return trace_seq_printf(s, "[%s]\n", cmd);
1233 }
1234 }
1235
1236 static int blk_log_with_error(struct trace_seq *s,
1237 const struct trace_entry *ent)
1238 {
1239 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1240 int ret;
1241
1242 ret = blk_log_dump_pdu(s, ent);
1243 if (ret)
1244 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1245 return 0;
1246 } else {
1247 if (t_sec(ent))
1248 return trace_seq_printf(s, "%llu + %u [%d]\n",
1249 t_sector(ent),
1250 t_sec(ent), t_error(ent));
1251 return trace_seq_printf(s, "%llu [%d]\n",
1252 t_sector(ent), t_error(ent));
1253 }
1254 }
1255
1256 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1257 {
1258 struct blk_io_trace_remap r = { .device_from = 0, };
1259
1260 get_pdu_remap(ent, &r);
1261 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1262 t_sector(ent), t_sec(ent),
1263 MAJOR(r.device_from), MINOR(r.device_from),
1264 (unsigned long long)r.sector_from);
1265 }
1266
1267 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1268 {
1269 char cmd[TASK_COMM_LEN];
1270
1271 trace_find_cmdline(ent->pid, cmd);
1272
1273 return trace_seq_printf(s, "[%s]\n", cmd);
1274 }
1275
1276 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1277 {
1278 char cmd[TASK_COMM_LEN];
1279
1280 trace_find_cmdline(ent->pid, cmd);
1281
1282 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1283 }
1284
1285 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1286 {
1287 char cmd[TASK_COMM_LEN];
1288
1289 trace_find_cmdline(ent->pid, cmd);
1290
1291 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1292 get_pdu_int(ent), cmd);
1293 }
1294
1295 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1296 {
1297 int ret;
1298 const struct blk_io_trace *t = te_blk_io_trace(ent);
1299
1300 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1301 if (ret)
1302 return trace_seq_putc(s, '\n');
1303 return ret;
1304 }
1305
1306 /*
1307 * struct tracer operations
1308 */
1309
1310 static void blk_tracer_print_header(struct seq_file *m)
1311 {
1312 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1313 return;
1314 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1315 "# | | | | | |\n");
1316 }
1317
1318 static void blk_tracer_start(struct trace_array *tr)
1319 {
1320 blk_tracer_enabled = true;
1321 }
1322
1323 static int blk_tracer_init(struct trace_array *tr)
1324 {
1325 blk_tr = tr;
1326 blk_tracer_start(tr);
1327 return 0;
1328 }
1329
1330 static void blk_tracer_stop(struct trace_array *tr)
1331 {
1332 blk_tracer_enabled = false;
1333 }
1334
1335 static void blk_tracer_reset(struct trace_array *tr)
1336 {
1337 blk_tracer_stop(tr);
1338 }
1339
1340 static const struct {
1341 const char *act[2];
1342 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1343 } what2act[] = {
1344 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1345 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1346 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1347 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1348 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1349 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1350 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1351 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1352 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1353 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1354 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1355 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1356 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1357 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1358 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1359 };
1360
1361 static enum print_line_t print_one_line(struct trace_iterator *iter,
1362 bool classic)
1363 {
1364 struct trace_seq *s = &iter->seq;
1365 const struct blk_io_trace *t;
1366 u16 what;
1367 int ret;
1368 bool long_act;
1369 blk_log_action_t *log_action;
1370
1371 t = te_blk_io_trace(iter->ent);
1372 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1373 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1374 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1375
1376 if (t->action == BLK_TN_MESSAGE) {
1377 ret = log_action(iter, long_act ? "message" : "m");
1378 if (ret)
1379 ret = blk_log_msg(s, iter->ent);
1380 goto out;
1381 }
1382
1383 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1384 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1385 else {
1386 ret = log_action(iter, what2act[what].act[long_act]);
1387 if (ret)
1388 ret = what2act[what].print(s, iter->ent);
1389 }
1390 out:
1391 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1392 }
1393
1394 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1395 int flags, struct trace_event *event)
1396 {
1397 return print_one_line(iter, false);
1398 }
1399
1400 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1401 {
1402 struct trace_seq *s = &iter->seq;
1403 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1404 const int offset = offsetof(struct blk_io_trace, sector);
1405 struct blk_io_trace old = {
1406 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1407 .time = iter->ts,
1408 };
1409
1410 if (!trace_seq_putmem(s, &old, offset))
1411 return 0;
1412 return trace_seq_putmem(s, &t->sector,
1413 sizeof(old) - offset + t->pdu_len);
1414 }
1415
1416 static enum print_line_t
1417 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1418 struct trace_event *event)
1419 {
1420 return blk_trace_synthesize_old_trace(iter) ?
1421 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1422 }
1423
1424 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1425 {
1426 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1427 return TRACE_TYPE_UNHANDLED;
1428
1429 return print_one_line(iter, true);
1430 }
1431
1432 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1433 {
1434 /* don't output context-info for blk_classic output */
1435 if (bit == TRACE_BLK_OPT_CLASSIC) {
1436 if (set)
1437 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1438 else
1439 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1440 }
1441 return 0;
1442 }
1443
1444 static struct tracer blk_tracer __read_mostly = {
1445 .name = "blk",
1446 .init = blk_tracer_init,
1447 .reset = blk_tracer_reset,
1448 .start = blk_tracer_start,
1449 .stop = blk_tracer_stop,
1450 .print_header = blk_tracer_print_header,
1451 .print_line = blk_tracer_print_line,
1452 .flags = &blk_tracer_flags,
1453 .set_flag = blk_tracer_set_flag,
1454 };
1455
1456 static struct trace_event_functions trace_blk_event_funcs = {
1457 .trace = blk_trace_event_print,
1458 .binary = blk_trace_event_print_binary,
1459 };
1460
1461 static struct trace_event trace_blk_event = {
1462 .type = TRACE_BLK,
1463 .funcs = &trace_blk_event_funcs,
1464 };
1465
1466 static int __init init_blk_tracer(void)
1467 {
1468 if (!register_ftrace_event(&trace_blk_event)) {
1469 pr_warning("Warning: could not register block events\n");
1470 return 1;
1471 }
1472
1473 if (register_tracer(&blk_tracer) != 0) {
1474 pr_warning("Warning: could not register the block tracer\n");
1475 unregister_ftrace_event(&trace_blk_event);
1476 return 1;
1477 }
1478
1479 return 0;
1480 }
1481
1482 device_initcall(init_blk_tracer);
1483
1484 static int blk_trace_remove_queue(struct request_queue *q)
1485 {
1486 struct blk_trace *bt;
1487
1488 bt = xchg(&q->blk_trace, NULL);
1489 if (bt == NULL)
1490 return -EINVAL;
1491
1492 if (atomic_dec_and_test(&blk_probes_ref))
1493 blk_unregister_tracepoints();
1494
1495 blk_trace_free(bt);
1496 return 0;
1497 }
1498
1499 /*
1500 * Setup everything required to start tracing
1501 */
1502 static int blk_trace_setup_queue(struct request_queue *q,
1503 struct block_device *bdev)
1504 {
1505 struct blk_trace *old_bt, *bt = NULL;
1506 int ret = -ENOMEM;
1507
1508 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1509 if (!bt)
1510 return -ENOMEM;
1511
1512 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1513 if (!bt->msg_data)
1514 goto free_bt;
1515
1516 bt->dev = bdev->bd_dev;
1517 bt->act_mask = (u16)-1;
1518
1519 blk_trace_setup_lba(bt, bdev);
1520
1521 old_bt = xchg(&q->blk_trace, bt);
1522 if (old_bt != NULL) {
1523 (void)xchg(&q->blk_trace, old_bt);
1524 ret = -EBUSY;
1525 goto free_bt;
1526 }
1527
1528 if (atomic_inc_return(&blk_probes_ref) == 1)
1529 blk_register_tracepoints();
1530 return 0;
1531
1532 free_bt:
1533 blk_trace_free(bt);
1534 return ret;
1535 }
1536
1537 /*
1538 * sysfs interface to enable and configure tracing
1539 */
1540
1541 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1542 struct device_attribute *attr,
1543 char *buf);
1544 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1545 struct device_attribute *attr,
1546 const char *buf, size_t count);
1547 #define BLK_TRACE_DEVICE_ATTR(_name) \
1548 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1549 sysfs_blk_trace_attr_show, \
1550 sysfs_blk_trace_attr_store)
1551
1552 static BLK_TRACE_DEVICE_ATTR(enable);
1553 static BLK_TRACE_DEVICE_ATTR(act_mask);
1554 static BLK_TRACE_DEVICE_ATTR(pid);
1555 static BLK_TRACE_DEVICE_ATTR(start_lba);
1556 static BLK_TRACE_DEVICE_ATTR(end_lba);
1557
1558 static struct attribute *blk_trace_attrs[] = {
1559 &dev_attr_enable.attr,
1560 &dev_attr_act_mask.attr,
1561 &dev_attr_pid.attr,
1562 &dev_attr_start_lba.attr,
1563 &dev_attr_end_lba.attr,
1564 NULL
1565 };
1566
1567 struct attribute_group blk_trace_attr_group = {
1568 .name = "trace",
1569 .attrs = blk_trace_attrs,
1570 };
1571
1572 static const struct {
1573 int mask;
1574 const char *str;
1575 } mask_maps[] = {
1576 { BLK_TC_READ, "read" },
1577 { BLK_TC_WRITE, "write" },
1578 { BLK_TC_FLUSH, "flush" },
1579 { BLK_TC_SYNC, "sync" },
1580 { BLK_TC_QUEUE, "queue" },
1581 { BLK_TC_REQUEUE, "requeue" },
1582 { BLK_TC_ISSUE, "issue" },
1583 { BLK_TC_COMPLETE, "complete" },
1584 { BLK_TC_FS, "fs" },
1585 { BLK_TC_PC, "pc" },
1586 { BLK_TC_AHEAD, "ahead" },
1587 { BLK_TC_META, "meta" },
1588 { BLK_TC_DISCARD, "discard" },
1589 { BLK_TC_DRV_DATA, "drv_data" },
1590 { BLK_TC_FUA, "fua" },
1591 };
1592
1593 static int blk_trace_str2mask(const char *str)
1594 {
1595 int i;
1596 int mask = 0;
1597 char *buf, *s, *token;
1598
1599 buf = kstrdup(str, GFP_KERNEL);
1600 if (buf == NULL)
1601 return -ENOMEM;
1602 s = strstrip(buf);
1603
1604 while (1) {
1605 token = strsep(&s, ",");
1606 if (token == NULL)
1607 break;
1608
1609 if (*token == '\0')
1610 continue;
1611
1612 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1613 if (strcasecmp(token, mask_maps[i].str) == 0) {
1614 mask |= mask_maps[i].mask;
1615 break;
1616 }
1617 }
1618 if (i == ARRAY_SIZE(mask_maps)) {
1619 mask = -EINVAL;
1620 break;
1621 }
1622 }
1623 kfree(buf);
1624
1625 return mask;
1626 }
1627
1628 static ssize_t blk_trace_mask2str(char *buf, int mask)
1629 {
1630 int i;
1631 char *p = buf;
1632
1633 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1634 if (mask & mask_maps[i].mask) {
1635 p += sprintf(p, "%s%s",
1636 (p == buf) ? "" : ",", mask_maps[i].str);
1637 }
1638 }
1639 *p++ = '\n';
1640
1641 return p - buf;
1642 }
1643
1644 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1645 {
1646 if (bdev->bd_disk == NULL)
1647 return NULL;
1648
1649 return bdev_get_queue(bdev);
1650 }
1651
1652 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1653 struct device_attribute *attr,
1654 char *buf)
1655 {
1656 struct hd_struct *p = dev_to_part(dev);
1657 struct request_queue *q;
1658 struct block_device *bdev;
1659 ssize_t ret = -ENXIO;
1660
1661 bdev = bdget(part_devt(p));
1662 if (bdev == NULL)
1663 goto out;
1664
1665 q = blk_trace_get_queue(bdev);
1666 if (q == NULL)
1667 goto out_bdput;
1668
1669 mutex_lock(&bdev->bd_mutex);
1670
1671 if (attr == &dev_attr_enable) {
1672 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1673 goto out_unlock_bdev;
1674 }
1675
1676 if (q->blk_trace == NULL)
1677 ret = sprintf(buf, "disabled\n");
1678 else if (attr == &dev_attr_act_mask)
1679 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1680 else if (attr == &dev_attr_pid)
1681 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1682 else if (attr == &dev_attr_start_lba)
1683 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1684 else if (attr == &dev_attr_end_lba)
1685 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1686
1687 out_unlock_bdev:
1688 mutex_unlock(&bdev->bd_mutex);
1689 out_bdput:
1690 bdput(bdev);
1691 out:
1692 return ret;
1693 }
1694
1695 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1696 struct device_attribute *attr,
1697 const char *buf, size_t count)
1698 {
1699 struct block_device *bdev;
1700 struct request_queue *q;
1701 struct hd_struct *p;
1702 u64 value;
1703 ssize_t ret = -EINVAL;
1704
1705 if (count == 0)
1706 goto out;
1707
1708 if (attr == &dev_attr_act_mask) {
1709 if (sscanf(buf, "%llx", &value) != 1) {
1710 /* Assume it is a list of trace category names */
1711 ret = blk_trace_str2mask(buf);
1712 if (ret < 0)
1713 goto out;
1714 value = ret;
1715 }
1716 } else if (sscanf(buf, "%llu", &value) != 1)
1717 goto out;
1718
1719 ret = -ENXIO;
1720
1721 p = dev_to_part(dev);
1722 bdev = bdget(part_devt(p));
1723 if (bdev == NULL)
1724 goto out;
1725
1726 q = blk_trace_get_queue(bdev);
1727 if (q == NULL)
1728 goto out_bdput;
1729
1730 mutex_lock(&bdev->bd_mutex);
1731
1732 if (attr == &dev_attr_enable) {
1733 if (value)
1734 ret = blk_trace_setup_queue(q, bdev);
1735 else
1736 ret = blk_trace_remove_queue(q);
1737 goto out_unlock_bdev;
1738 }
1739
1740 ret = 0;
1741 if (q->blk_trace == NULL)
1742 ret = blk_trace_setup_queue(q, bdev);
1743
1744 if (ret == 0) {
1745 if (attr == &dev_attr_act_mask)
1746 q->blk_trace->act_mask = value;
1747 else if (attr == &dev_attr_pid)
1748 q->blk_trace->pid = value;
1749 else if (attr == &dev_attr_start_lba)
1750 q->blk_trace->start_lba = value;
1751 else if (attr == &dev_attr_end_lba)
1752 q->blk_trace->end_lba = value;
1753 }
1754
1755 out_unlock_bdev:
1756 mutex_unlock(&bdev->bd_mutex);
1757 out_bdput:
1758 bdput(bdev);
1759 out:
1760 return ret ? ret : count;
1761 }
1762
1763 int blk_trace_init_sysfs(struct device *dev)
1764 {
1765 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1766 }
1767
1768 void blk_trace_remove_sysfs(struct device *dev)
1769 {
1770 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1771 }
1772
1773 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1774
1775 #ifdef CONFIG_EVENT_TRACING
1776
1777 void blk_dump_cmd(char *buf, struct request *rq)
1778 {
1779 int i, end;
1780 int len = rq->cmd_len;
1781 unsigned char *cmd = rq->cmd;
1782
1783 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1784 buf[0] = '\0';
1785 return;
1786 }
1787
1788 for (end = len - 1; end >= 0; end--)
1789 if (cmd[end])
1790 break;
1791 end++;
1792
1793 for (i = 0; i < len; i++) {
1794 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1795 if (i == end && end != len - 1) {
1796 sprintf(buf, " ..");
1797 break;
1798 }
1799 }
1800 }
1801
1802 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1803 {
1804 int i = 0;
1805
1806 if (rw & REQ_FLUSH)
1807 rwbs[i++] = 'F';
1808
1809 if (rw & WRITE)
1810 rwbs[i++] = 'W';
1811 else if (rw & REQ_DISCARD)
1812 rwbs[i++] = 'D';
1813 else if (bytes)
1814 rwbs[i++] = 'R';
1815 else
1816 rwbs[i++] = 'N';
1817
1818 if (rw & REQ_FUA)
1819 rwbs[i++] = 'F';
1820 if (rw & REQ_RAHEAD)
1821 rwbs[i++] = 'A';
1822 if (rw & REQ_SYNC)
1823 rwbs[i++] = 'S';
1824 if (rw & REQ_META)
1825 rwbs[i++] = 'M';
1826 if (rw & REQ_SECURE)
1827 rwbs[i++] = 'E';
1828
1829 rwbs[i] = '\0';
1830 }
1831
1832 #endif /* CONFIG_EVENT_TRACING */
1833
Linux kernel - Deliverables
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