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Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs
[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/time.h>
27 #include <linux/uaccess.h>
28
29 #include <trace/events/block.h>
30
31 #include "trace_output.h"
32
33 #ifdef CONFIG_BLK_DEV_IO_TRACE
34
35 static unsigned int blktrace_seq __read_mostly = 1;
36
37 static struct trace_array *blk_tr;
38 static bool blk_tracer_enabled __read_mostly;
39
40 /* Select an alternative, minimalistic output than the original one */
41 #define TRACE_BLK_OPT_CLASSIC 0x1
42
43 static struct tracer_opt blk_tracer_opts[] = {
44 /* Default disable the minimalistic output */
45 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
46 { }
47 };
48
49 static struct tracer_flags blk_tracer_flags = {
50 .val = 0,
51 .opts = blk_tracer_opts,
52 };
53
54 /* Global reference count of probes */
55 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
56
57 static void blk_register_tracepoints(void);
58 static void blk_unregister_tracepoints(void);
59
60 /*
61 * Send out a notify message.
62 */
63 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
64 const void *data, size_t len)
65 {
66 struct blk_io_trace *t;
67 struct ring_buffer_event *event = NULL;
68 struct ring_buffer *buffer = NULL;
69 int pc = 0;
70 int cpu = smp_processor_id();
71 bool blk_tracer = blk_tracer_enabled;
72
73 if (blk_tracer) {
74 buffer = blk_tr->buffer;
75 pc = preempt_count();
76 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
77 sizeof(*t) + len,
78 0, pc);
79 if (!event)
80 return;
81 t = ring_buffer_event_data(event);
82 goto record_it;
83 }
84
85 if (!bt->rchan)
86 return;
87
88 t = relay_reserve(bt->rchan, sizeof(*t) + len);
89 if (t) {
90 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
91 t->time = ktime_to_ns(ktime_get());
92 record_it:
93 t->device = bt->dev;
94 t->action = action;
95 t->pid = pid;
96 t->cpu = cpu;
97 t->pdu_len = len;
98 memcpy((void *) t + sizeof(*t), data, len);
99
100 if (blk_tracer)
101 trace_buffer_unlock_commit(buffer, event, 0, pc);
102 }
103 }
104
105 /*
106 * Send out a notify for this process, if we haven't done so since a trace
107 * started
108 */
109 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
110 {
111 tsk->btrace_seq = blktrace_seq;
112 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
113 }
114
115 static void trace_note_time(struct blk_trace *bt)
116 {
117 struct timespec now;
118 unsigned long flags;
119 u32 words[2];
120
121 getnstimeofday(&now);
122 words[0] = now.tv_sec;
123 words[1] = now.tv_nsec;
124
125 local_irq_save(flags);
126 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
127 local_irq_restore(flags);
128 }
129
130 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
131 {
132 int n;
133 va_list args;
134 unsigned long flags;
135 char *buf;
136
137 if (unlikely(bt->trace_state != Blktrace_running &&
138 !blk_tracer_enabled))
139 return;
140
141 /*
142 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
143 * message to the trace.
144 */
145 if (!(bt->act_mask & BLK_TC_NOTIFY))
146 return;
147
148 local_irq_save(flags);
149 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
150 va_start(args, fmt);
151 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
152 va_end(args);
153
154 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
155 local_irq_restore(flags);
156 }
157 EXPORT_SYMBOL_GPL(__trace_note_message);
158
159 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
160 pid_t pid)
161 {
162 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
163 return 1;
164 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
165 return 1;
166 if (bt->pid && pid != bt->pid)
167 return 1;
168
169 return 0;
170 }
171
172 /*
173 * Data direction bit lookup
174 */
175 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
176 BLK_TC_ACT(BLK_TC_WRITE) };
177
178 #define BLK_TC_RAHEAD BLK_TC_AHEAD
179
180 /* The ilog2() calls fall out because they're constant */
181 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
182 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
183
184 /*
185 * The worker for the various blk_add_trace*() types. Fills out a
186 * blk_io_trace structure and places it in a per-cpu subbuffer.
187 */
188 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
189 int rw, u32 what, int error, int pdu_len, void *pdu_data)
190 {
191 struct task_struct *tsk = current;
192 struct ring_buffer_event *event = NULL;
193 struct ring_buffer *buffer = NULL;
194 struct blk_io_trace *t;
195 unsigned long flags = 0;
196 unsigned long *sequence;
197 pid_t pid;
198 int cpu, pc = 0;
199 bool blk_tracer = blk_tracer_enabled;
200
201 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
202 return;
203
204 what |= ddir_act[rw & WRITE];
205 what |= MASK_TC_BIT(rw, SYNC);
206 what |= MASK_TC_BIT(rw, RAHEAD);
207 what |= MASK_TC_BIT(rw, META);
208 what |= MASK_TC_BIT(rw, DISCARD);
209
210 pid = tsk->pid;
211 if (act_log_check(bt, what, sector, pid))
212 return;
213 cpu = raw_smp_processor_id();
214
215 if (blk_tracer) {
216 tracing_record_cmdline(current);
217
218 buffer = blk_tr->buffer;
219 pc = preempt_count();
220 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
221 sizeof(*t) + pdu_len,
222 0, pc);
223 if (!event)
224 return;
225 t = ring_buffer_event_data(event);
226 goto record_it;
227 }
228
229 /*
230 * A word about the locking here - we disable interrupts to reserve
231 * some space in the relay per-cpu buffer, to prevent an irq
232 * from coming in and stepping on our toes.
233 */
234 local_irq_save(flags);
235
236 if (unlikely(tsk->btrace_seq != blktrace_seq))
237 trace_note_tsk(bt, tsk);
238
239 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
240 if (t) {
241 sequence = per_cpu_ptr(bt->sequence, cpu);
242
243 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
244 t->sequence = ++(*sequence);
245 t->time = ktime_to_ns(ktime_get());
246 record_it:
247 /*
248 * These two are not needed in ftrace as they are in the
249 * generic trace_entry, filled by tracing_generic_entry_update,
250 * but for the trace_event->bin() synthesizer benefit we do it
251 * here too.
252 */
253 t->cpu = cpu;
254 t->pid = pid;
255
256 t->sector = sector;
257 t->bytes = bytes;
258 t->action = what;
259 t->device = bt->dev;
260 t->error = error;
261 t->pdu_len = pdu_len;
262
263 if (pdu_len)
264 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
265
266 if (blk_tracer) {
267 trace_buffer_unlock_commit(buffer, event, 0, pc);
268 return;
269 }
270 }
271
272 local_irq_restore(flags);
273 }
274
275 static struct dentry *blk_tree_root;
276 static DEFINE_MUTEX(blk_tree_mutex);
277
278 static void blk_trace_free(struct blk_trace *bt)
279 {
280 debugfs_remove(bt->msg_file);
281 debugfs_remove(bt->dropped_file);
282 relay_close(bt->rchan);
283 debugfs_remove(bt->dir);
284 free_percpu(bt->sequence);
285 free_percpu(bt->msg_data);
286 kfree(bt);
287 }
288
289 static void blk_trace_cleanup(struct blk_trace *bt)
290 {
291 blk_trace_free(bt);
292 if (atomic_dec_and_test(&blk_probes_ref))
293 blk_unregister_tracepoints();
294 }
295
296 int blk_trace_remove(struct request_queue *q)
297 {
298 struct blk_trace *bt;
299
300 bt = xchg(&q->blk_trace, NULL);
301 if (!bt)
302 return -EINVAL;
303
304 if (bt->trace_state != Blktrace_running)
305 blk_trace_cleanup(bt);
306
307 return 0;
308 }
309 EXPORT_SYMBOL_GPL(blk_trace_remove);
310
311 static int blk_dropped_open(struct inode *inode, struct file *filp)
312 {
313 filp->private_data = inode->i_private;
314
315 return 0;
316 }
317
318 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
319 size_t count, loff_t *ppos)
320 {
321 struct blk_trace *bt = filp->private_data;
322 char buf[16];
323
324 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
325
326 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
327 }
328
329 static const struct file_operations blk_dropped_fops = {
330 .owner = THIS_MODULE,
331 .open = blk_dropped_open,
332 .read = blk_dropped_read,
333 .llseek = default_llseek,
334 };
335
336 static int blk_msg_open(struct inode *inode, struct file *filp)
337 {
338 filp->private_data = inode->i_private;
339
340 return 0;
341 }
342
343 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
344 size_t count, loff_t *ppos)
345 {
346 char *msg;
347 struct blk_trace *bt;
348
349 if (count >= BLK_TN_MAX_MSG)
350 return -EINVAL;
351
352 msg = kmalloc(count + 1, GFP_KERNEL);
353 if (msg == NULL)
354 return -ENOMEM;
355
356 if (copy_from_user(msg, buffer, count)) {
357 kfree(msg);
358 return -EFAULT;
359 }
360
361 msg[count] = '\0';
362 bt = filp->private_data;
363 __trace_note_message(bt, "%s", msg);
364 kfree(msg);
365
366 return count;
367 }
368
369 static const struct file_operations blk_msg_fops = {
370 .owner = THIS_MODULE,
371 .open = blk_msg_open,
372 .write = blk_msg_write,
373 .llseek = noop_llseek,
374 };
375
376 /*
377 * Keep track of how many times we encountered a full subbuffer, to aid
378 * the user space app in telling how many lost events there were.
379 */
380 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
381 void *prev_subbuf, size_t prev_padding)
382 {
383 struct blk_trace *bt;
384
385 if (!relay_buf_full(buf))
386 return 1;
387
388 bt = buf->chan->private_data;
389 atomic_inc(&bt->dropped);
390 return 0;
391 }
392
393 static int blk_remove_buf_file_callback(struct dentry *dentry)
394 {
395 debugfs_remove(dentry);
396
397 return 0;
398 }
399
400 static struct dentry *blk_create_buf_file_callback(const char *filename,
401 struct dentry *parent,
402 int mode,
403 struct rchan_buf *buf,
404 int *is_global)
405 {
406 return debugfs_create_file(filename, mode, parent, buf,
407 &relay_file_operations);
408 }
409
410 static struct rchan_callbacks blk_relay_callbacks = {
411 .subbuf_start = blk_subbuf_start_callback,
412 .create_buf_file = blk_create_buf_file_callback,
413 .remove_buf_file = blk_remove_buf_file_callback,
414 };
415
416 static void blk_trace_setup_lba(struct blk_trace *bt,
417 struct block_device *bdev)
418 {
419 struct hd_struct *part = NULL;
420
421 if (bdev)
422 part = bdev->bd_part;
423
424 if (part) {
425 bt->start_lba = part->start_sect;
426 bt->end_lba = part->start_sect + part->nr_sects;
427 } else {
428 bt->start_lba = 0;
429 bt->end_lba = -1ULL;
430 }
431 }
432
433 /*
434 * Setup everything required to start tracing
435 */
436 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
437 struct block_device *bdev,
438 struct blk_user_trace_setup *buts)
439 {
440 struct blk_trace *old_bt, *bt = NULL;
441 struct dentry *dir = NULL;
442 int ret, i;
443
444 if (!buts->buf_size || !buts->buf_nr)
445 return -EINVAL;
446
447 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
448 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
449
450 /*
451 * some device names have larger paths - convert the slashes
452 * to underscores for this to work as expected
453 */
454 for (i = 0; i < strlen(buts->name); i++)
455 if (buts->name[i] == '/')
456 buts->name[i] = '_';
457
458 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
459 if (!bt)
460 return -ENOMEM;
461
462 ret = -ENOMEM;
463 bt->sequence = alloc_percpu(unsigned long);
464 if (!bt->sequence)
465 goto err;
466
467 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
468 if (!bt->msg_data)
469 goto err;
470
471 ret = -ENOENT;
472
473 mutex_lock(&blk_tree_mutex);
474 if (!blk_tree_root) {
475 blk_tree_root = debugfs_create_dir("block", NULL);
476 if (!blk_tree_root) {
477 mutex_unlock(&blk_tree_mutex);
478 goto err;
479 }
480 }
481 mutex_unlock(&blk_tree_mutex);
482
483 dir = debugfs_create_dir(buts->name, blk_tree_root);
484
485 if (!dir)
486 goto err;
487
488 bt->dir = dir;
489 bt->dev = dev;
490 atomic_set(&bt->dropped, 0);
491
492 ret = -EIO;
493 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
494 &blk_dropped_fops);
495 if (!bt->dropped_file)
496 goto err;
497
498 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
499 if (!bt->msg_file)
500 goto err;
501
502 bt->rchan = relay_open("trace", dir, buts->buf_size,
503 buts->buf_nr, &blk_relay_callbacks, bt);
504 if (!bt->rchan)
505 goto err;
506
507 bt->act_mask = buts->act_mask;
508 if (!bt->act_mask)
509 bt->act_mask = (u16) -1;
510
511 blk_trace_setup_lba(bt, bdev);
512
513 /* overwrite with user settings */
514 if (buts->start_lba)
515 bt->start_lba = buts->start_lba;
516 if (buts->end_lba)
517 bt->end_lba = buts->end_lba;
518
519 bt->pid = buts->pid;
520 bt->trace_state = Blktrace_setup;
521
522 ret = -EBUSY;
523 old_bt = xchg(&q->blk_trace, bt);
524 if (old_bt) {
525 (void) xchg(&q->blk_trace, old_bt);
526 goto err;
527 }
528
529 if (atomic_inc_return(&blk_probes_ref) == 1)
530 blk_register_tracepoints();
531
532 return 0;
533 err:
534 blk_trace_free(bt);
535 return ret;
536 }
537
538 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
539 struct block_device *bdev,
540 char __user *arg)
541 {
542 struct blk_user_trace_setup buts;
543 int ret;
544
545 ret = copy_from_user(&buts, arg, sizeof(buts));
546 if (ret)
547 return -EFAULT;
548
549 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
550 if (ret)
551 return ret;
552
553 if (copy_to_user(arg, &buts, sizeof(buts))) {
554 blk_trace_remove(q);
555 return -EFAULT;
556 }
557 return 0;
558 }
559 EXPORT_SYMBOL_GPL(blk_trace_setup);
560
561 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
562 static int compat_blk_trace_setup(struct request_queue *q, char *name,
563 dev_t dev, struct block_device *bdev,
564 char __user *arg)
565 {
566 struct blk_user_trace_setup buts;
567 struct compat_blk_user_trace_setup cbuts;
568 int ret;
569
570 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
571 return -EFAULT;
572
573 buts = (struct blk_user_trace_setup) {
574 .act_mask = cbuts.act_mask,
575 .buf_size = cbuts.buf_size,
576 .buf_nr = cbuts.buf_nr,
577 .start_lba = cbuts.start_lba,
578 .end_lba = cbuts.end_lba,
579 .pid = cbuts.pid,
580 };
581 memcpy(&buts.name, &cbuts.name, 32);
582
583 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
584 if (ret)
585 return ret;
586
587 if (copy_to_user(arg, &buts.name, 32)) {
588 blk_trace_remove(q);
589 return -EFAULT;
590 }
591
592 return 0;
593 }
594 #endif
595
596 int blk_trace_startstop(struct request_queue *q, int start)
597 {
598 int ret;
599 struct blk_trace *bt = q->blk_trace;
600
601 if (bt == NULL)
602 return -EINVAL;
603
604 /*
605 * For starting a trace, we can transition from a setup or stopped
606 * trace. For stopping a trace, the state must be running
607 */
608 ret = -EINVAL;
609 if (start) {
610 if (bt->trace_state == Blktrace_setup ||
611 bt->trace_state == Blktrace_stopped) {
612 blktrace_seq++;
613 smp_mb();
614 bt->trace_state = Blktrace_running;
615
616 trace_note_time(bt);
617 ret = 0;
618 }
619 } else {
620 if (bt->trace_state == Blktrace_running) {
621 bt->trace_state = Blktrace_stopped;
622 relay_flush(bt->rchan);
623 ret = 0;
624 }
625 }
626
627 return ret;
628 }
629 EXPORT_SYMBOL_GPL(blk_trace_startstop);
630
631 /**
632 * blk_trace_ioctl: - handle the ioctls associated with tracing
633 * @bdev: the block device
634 * @cmd: the ioctl cmd
635 * @arg: the argument data, if any
636 *
637 **/
638 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
639 {
640 struct request_queue *q;
641 int ret, start = 0;
642 char b[BDEVNAME_SIZE];
643
644 q = bdev_get_queue(bdev);
645 if (!q)
646 return -ENXIO;
647
648 mutex_lock(&bdev->bd_mutex);
649
650 switch (cmd) {
651 case BLKTRACESETUP:
652 bdevname(bdev, b);
653 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
654 break;
655 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
656 case BLKTRACESETUP32:
657 bdevname(bdev, b);
658 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
659 break;
660 #endif
661 case BLKTRACESTART:
662 start = 1;
663 case BLKTRACESTOP:
664 ret = blk_trace_startstop(q, start);
665 break;
666 case BLKTRACETEARDOWN:
667 ret = blk_trace_remove(q);
668 break;
669 default:
670 ret = -ENOTTY;
671 break;
672 }
673
674 mutex_unlock(&bdev->bd_mutex);
675 return ret;
676 }
677
678 /**
679 * blk_trace_shutdown: - stop and cleanup trace structures
680 * @q: the request queue associated with the device
681 *
682 **/
683 void blk_trace_shutdown(struct request_queue *q)
684 {
685 if (q->blk_trace) {
686 blk_trace_startstop(q, 0);
687 blk_trace_remove(q);
688 }
689 }
690
691 /*
692 * blktrace probes
693 */
694
695 /**
696 * blk_add_trace_rq - Add a trace for a request oriented action
697 * @q: queue the io is for
698 * @rq: the source request
699 * @what: the action
700 *
701 * Description:
702 * Records an action against a request. Will log the bio offset + size.
703 *
704 **/
705 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
706 u32 what)
707 {
708 struct blk_trace *bt = q->blk_trace;
709
710 if (likely(!bt))
711 return;
712
713 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
714 what |= BLK_TC_ACT(BLK_TC_PC);
715 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
716 what, rq->errors, rq->cmd_len, rq->cmd);
717 } else {
718 what |= BLK_TC_ACT(BLK_TC_FS);
719 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
720 rq->cmd_flags, what, rq->errors, 0, NULL);
721 }
722 }
723
724 static void blk_add_trace_rq_abort(void *ignore,
725 struct request_queue *q, struct request *rq)
726 {
727 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
728 }
729
730 static void blk_add_trace_rq_insert(void *ignore,
731 struct request_queue *q, struct request *rq)
732 {
733 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
734 }
735
736 static void blk_add_trace_rq_issue(void *ignore,
737 struct request_queue *q, struct request *rq)
738 {
739 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
740 }
741
742 static void blk_add_trace_rq_requeue(void *ignore,
743 struct request_queue *q,
744 struct request *rq)
745 {
746 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
747 }
748
749 static void blk_add_trace_rq_complete(void *ignore,
750 struct request_queue *q,
751 struct request *rq)
752 {
753 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
754 }
755
756 /**
757 * blk_add_trace_bio - Add a trace for a bio oriented action
758 * @q: queue the io is for
759 * @bio: the source bio
760 * @what: the action
761 * @error: error, if any
762 *
763 * Description:
764 * Records an action against a bio. Will log the bio offset + size.
765 *
766 **/
767 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
768 u32 what, int error)
769 {
770 struct blk_trace *bt = q->blk_trace;
771
772 if (likely(!bt))
773 return;
774
775 if (!error && !bio_flagged(bio, BIO_UPTODATE))
776 error = EIO;
777
778 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
779 error, 0, NULL);
780 }
781
782 static void blk_add_trace_bio_bounce(void *ignore,
783 struct request_queue *q, struct bio *bio)
784 {
785 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
786 }
787
788 static void blk_add_trace_bio_complete(void *ignore,
789 struct request_queue *q, struct bio *bio,
790 int error)
791 {
792 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
793 }
794
795 static void blk_add_trace_bio_backmerge(void *ignore,
796 struct request_queue *q,
797 struct bio *bio)
798 {
799 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
800 }
801
802 static void blk_add_trace_bio_frontmerge(void *ignore,
803 struct request_queue *q,
804 struct bio *bio)
805 {
806 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
807 }
808
809 static void blk_add_trace_bio_queue(void *ignore,
810 struct request_queue *q, struct bio *bio)
811 {
812 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
813 }
814
815 static void blk_add_trace_getrq(void *ignore,
816 struct request_queue *q,
817 struct bio *bio, int rw)
818 {
819 if (bio)
820 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
821 else {
822 struct blk_trace *bt = q->blk_trace;
823
824 if (bt)
825 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
826 }
827 }
828
829
830 static void blk_add_trace_sleeprq(void *ignore,
831 struct request_queue *q,
832 struct bio *bio, int rw)
833 {
834 if (bio)
835 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
836 else {
837 struct blk_trace *bt = q->blk_trace;
838
839 if (bt)
840 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
841 0, 0, NULL);
842 }
843 }
844
845 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
846 {
847 struct blk_trace *bt = q->blk_trace;
848
849 if (bt)
850 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
851 }
852
853 static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q)
854 {
855 struct blk_trace *bt = q->blk_trace;
856
857 if (bt) {
858 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
859 __be64 rpdu = cpu_to_be64(pdu);
860
861 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
862 sizeof(rpdu), &rpdu);
863 }
864 }
865
866 static void blk_add_trace_unplug_timer(void *ignore, struct request_queue *q)
867 {
868 struct blk_trace *bt = q->blk_trace;
869
870 if (bt) {
871 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
872 __be64 rpdu = cpu_to_be64(pdu);
873
874 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
875 sizeof(rpdu), &rpdu);
876 }
877 }
878
879 static void blk_add_trace_split(void *ignore,
880 struct request_queue *q, struct bio *bio,
881 unsigned int pdu)
882 {
883 struct blk_trace *bt = q->blk_trace;
884
885 if (bt) {
886 __be64 rpdu = cpu_to_be64(pdu);
887
888 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
889 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
890 sizeof(rpdu), &rpdu);
891 }
892 }
893
894 /**
895 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
896 * @ignore: trace callback data parameter (not used)
897 * @q: queue the io is for
898 * @bio: the source bio
899 * @dev: target device
900 * @from: source sector
901 *
902 * Description:
903 * Device mapper or raid target sometimes need to split a bio because
904 * it spans a stripe (or similar). Add a trace for that action.
905 *
906 **/
907 static void blk_add_trace_bio_remap(void *ignore,
908 struct request_queue *q, struct bio *bio,
909 dev_t dev, sector_t from)
910 {
911 struct blk_trace *bt = q->blk_trace;
912 struct blk_io_trace_remap r;
913
914 if (likely(!bt))
915 return;
916
917 r.device_from = cpu_to_be32(dev);
918 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
919 r.sector_from = cpu_to_be64(from);
920
921 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
922 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
923 sizeof(r), &r);
924 }
925
926 /**
927 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
928 * @ignore: trace callback data parameter (not used)
929 * @q: queue the io is for
930 * @rq: the source request
931 * @dev: target device
932 * @from: source sector
933 *
934 * Description:
935 * Device mapper remaps request to other devices.
936 * Add a trace for that action.
937 *
938 **/
939 static void blk_add_trace_rq_remap(void *ignore,
940 struct request_queue *q,
941 struct request *rq, dev_t dev,
942 sector_t from)
943 {
944 struct blk_trace *bt = q->blk_trace;
945 struct blk_io_trace_remap r;
946
947 if (likely(!bt))
948 return;
949
950 r.device_from = cpu_to_be32(dev);
951 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
952 r.sector_from = cpu_to_be64(from);
953
954 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
955 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
956 sizeof(r), &r);
957 }
958
959 /**
960 * blk_add_driver_data - Add binary message with driver-specific data
961 * @q: queue the io is for
962 * @rq: io request
963 * @data: driver-specific data
964 * @len: length of driver-specific data
965 *
966 * Description:
967 * Some drivers might want to write driver-specific data per request.
968 *
969 **/
970 void blk_add_driver_data(struct request_queue *q,
971 struct request *rq,
972 void *data, size_t len)
973 {
974 struct blk_trace *bt = q->blk_trace;
975
976 if (likely(!bt))
977 return;
978
979 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
980 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
981 BLK_TA_DRV_DATA, rq->errors, len, data);
982 else
983 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
984 BLK_TA_DRV_DATA, rq->errors, len, data);
985 }
986 EXPORT_SYMBOL_GPL(blk_add_driver_data);
987
988 static void blk_register_tracepoints(void)
989 {
990 int ret;
991
992 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
993 WARN_ON(ret);
994 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
995 WARN_ON(ret);
996 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
997 WARN_ON(ret);
998 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
999 WARN_ON(ret);
1000 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1001 WARN_ON(ret);
1002 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1003 WARN_ON(ret);
1004 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1005 WARN_ON(ret);
1006 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1007 WARN_ON(ret);
1008 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1009 WARN_ON(ret);
1010 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1011 WARN_ON(ret);
1012 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1013 WARN_ON(ret);
1014 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1015 WARN_ON(ret);
1016 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1017 WARN_ON(ret);
1018 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
1019 WARN_ON(ret);
1020 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
1021 WARN_ON(ret);
1022 ret = register_trace_block_split(blk_add_trace_split, NULL);
1023 WARN_ON(ret);
1024 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1025 WARN_ON(ret);
1026 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1027 WARN_ON(ret);
1028 }
1029
1030 static void blk_unregister_tracepoints(void)
1031 {
1032 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1033 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1034 unregister_trace_block_split(blk_add_trace_split, NULL);
1035 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
1036 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, 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_DISCARD)
1069 rwbs[i++] = 'D';
1070 else if (tc & BLK_TC_WRITE)
1071 rwbs[i++] = 'W';
1072 else if (t->bytes)
1073 rwbs[i++] = 'R';
1074 else
1075 rwbs[i++] = 'N';
1076
1077 if (tc & BLK_TC_AHEAD)
1078 rwbs[i++] = 'A';
1079 if (tc & BLK_TC_BARRIER)
1080 rwbs[i++] = 'B';
1081 if (tc & BLK_TC_SYNC)
1082 rwbs[i++] = 'S';
1083 if (tc & BLK_TC_META)
1084 rwbs[i++] = 'M';
1085 out:
1086 rwbs[i] = '\0';
1087 }
1088
1089 static inline
1090 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1091 {
1092 return (const struct blk_io_trace *)ent;
1093 }
1094
1095 static inline const void *pdu_start(const struct trace_entry *ent)
1096 {
1097 return te_blk_io_trace(ent) + 1;
1098 }
1099
1100 static inline u32 t_action(const struct trace_entry *ent)
1101 {
1102 return te_blk_io_trace(ent)->action;
1103 }
1104
1105 static inline u32 t_bytes(const struct trace_entry *ent)
1106 {
1107 return te_blk_io_trace(ent)->bytes;
1108 }
1109
1110 static inline u32 t_sec(const struct trace_entry *ent)
1111 {
1112 return te_blk_io_trace(ent)->bytes >> 9;
1113 }
1114
1115 static inline unsigned long long t_sector(const struct trace_entry *ent)
1116 {
1117 return te_blk_io_trace(ent)->sector;
1118 }
1119
1120 static inline __u16 t_error(const struct trace_entry *ent)
1121 {
1122 return te_blk_io_trace(ent)->error;
1123 }
1124
1125 static __u64 get_pdu_int(const struct trace_entry *ent)
1126 {
1127 const __u64 *val = pdu_start(ent);
1128 return be64_to_cpu(*val);
1129 }
1130
1131 static void get_pdu_remap(const struct trace_entry *ent,
1132 struct blk_io_trace_remap *r)
1133 {
1134 const struct blk_io_trace_remap *__r = pdu_start(ent);
1135 __u64 sector_from = __r->sector_from;
1136
1137 r->device_from = be32_to_cpu(__r->device_from);
1138 r->device_to = be32_to_cpu(__r->device_to);
1139 r->sector_from = be64_to_cpu(sector_from);
1140 }
1141
1142 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1143
1144 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1145 {
1146 char rwbs[6];
1147 unsigned long long ts = iter->ts;
1148 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1149 unsigned secs = (unsigned long)ts;
1150 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1151
1152 fill_rwbs(rwbs, t);
1153
1154 return trace_seq_printf(&iter->seq,
1155 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1156 MAJOR(t->device), MINOR(t->device), iter->cpu,
1157 secs, nsec_rem, iter->ent->pid, act, rwbs);
1158 }
1159
1160 static int blk_log_action(struct trace_iterator *iter, const char *act)
1161 {
1162 char rwbs[6];
1163 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1164
1165 fill_rwbs(rwbs, t);
1166 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1167 MAJOR(t->device), MINOR(t->device), act, rwbs);
1168 }
1169
1170 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1171 {
1172 const unsigned char *pdu_buf;
1173 int pdu_len;
1174 int i, end, ret;
1175
1176 pdu_buf = pdu_start(ent);
1177 pdu_len = te_blk_io_trace(ent)->pdu_len;
1178
1179 if (!pdu_len)
1180 return 1;
1181
1182 /* find the last zero that needs to be printed */
1183 for (end = pdu_len - 1; end >= 0; end--)
1184 if (pdu_buf[end])
1185 break;
1186 end++;
1187
1188 if (!trace_seq_putc(s, '('))
1189 return 0;
1190
1191 for (i = 0; i < pdu_len; i++) {
1192
1193 ret = trace_seq_printf(s, "%s%02x",
1194 i == 0 ? "" : " ", pdu_buf[i]);
1195 if (!ret)
1196 return ret;
1197
1198 /*
1199 * stop when the rest is just zeroes and indicate so
1200 * with a ".." appended
1201 */
1202 if (i == end && end != pdu_len - 1)
1203 return trace_seq_puts(s, " ..) ");
1204 }
1205
1206 return trace_seq_puts(s, ") ");
1207 }
1208
1209 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1210 {
1211 char cmd[TASK_COMM_LEN];
1212
1213 trace_find_cmdline(ent->pid, cmd);
1214
1215 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1216 int ret;
1217
1218 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1219 if (!ret)
1220 return 0;
1221 ret = blk_log_dump_pdu(s, ent);
1222 if (!ret)
1223 return 0;
1224 return trace_seq_printf(s, "[%s]\n", cmd);
1225 } else {
1226 if (t_sec(ent))
1227 return trace_seq_printf(s, "%llu + %u [%s]\n",
1228 t_sector(ent), t_sec(ent), cmd);
1229 return trace_seq_printf(s, "[%s]\n", cmd);
1230 }
1231 }
1232
1233 static int blk_log_with_error(struct trace_seq *s,
1234 const struct trace_entry *ent)
1235 {
1236 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1237 int ret;
1238
1239 ret = blk_log_dump_pdu(s, ent);
1240 if (ret)
1241 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1242 return 0;
1243 } else {
1244 if (t_sec(ent))
1245 return trace_seq_printf(s, "%llu + %u [%d]\n",
1246 t_sector(ent),
1247 t_sec(ent), t_error(ent));
1248 return trace_seq_printf(s, "%llu [%d]\n",
1249 t_sector(ent), t_error(ent));
1250 }
1251 }
1252
1253 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1254 {
1255 struct blk_io_trace_remap r = { .device_from = 0, };
1256
1257 get_pdu_remap(ent, &r);
1258 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1259 t_sector(ent), t_sec(ent),
1260 MAJOR(r.device_from), MINOR(r.device_from),
1261 (unsigned long long)r.sector_from);
1262 }
1263
1264 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1265 {
1266 char cmd[TASK_COMM_LEN];
1267
1268 trace_find_cmdline(ent->pid, cmd);
1269
1270 return trace_seq_printf(s, "[%s]\n", cmd);
1271 }
1272
1273 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1274 {
1275 char cmd[TASK_COMM_LEN];
1276
1277 trace_find_cmdline(ent->pid, cmd);
1278
1279 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1280 }
1281
1282 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1283 {
1284 char cmd[TASK_COMM_LEN];
1285
1286 trace_find_cmdline(ent->pid, cmd);
1287
1288 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1289 get_pdu_int(ent), cmd);
1290 }
1291
1292 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1293 {
1294 int ret;
1295 const struct blk_io_trace *t = te_blk_io_trace(ent);
1296
1297 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1298 if (ret)
1299 return trace_seq_putc(s, '\n');
1300 return ret;
1301 }
1302
1303 /*
1304 * struct tracer operations
1305 */
1306
1307 static void blk_tracer_print_header(struct seq_file *m)
1308 {
1309 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1310 return;
1311 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1312 "# | | | | | |\n");
1313 }
1314
1315 static void blk_tracer_start(struct trace_array *tr)
1316 {
1317 blk_tracer_enabled = true;
1318 }
1319
1320 static int blk_tracer_init(struct trace_array *tr)
1321 {
1322 blk_tr = tr;
1323 blk_tracer_start(tr);
1324 return 0;
1325 }
1326
1327 static void blk_tracer_stop(struct trace_array *tr)
1328 {
1329 blk_tracer_enabled = false;
1330 }
1331
1332 static void blk_tracer_reset(struct trace_array *tr)
1333 {
1334 blk_tracer_stop(tr);
1335 }
1336
1337 static const struct {
1338 const char *act[2];
1339 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1340 } what2act[] = {
1341 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1342 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1343 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1344 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1345 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1346 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1347 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1348 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1349 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1350 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1351 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1352 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1353 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1354 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1355 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1356 };
1357
1358 static enum print_line_t print_one_line(struct trace_iterator *iter,
1359 bool classic)
1360 {
1361 struct trace_seq *s = &iter->seq;
1362 const struct blk_io_trace *t;
1363 u16 what;
1364 int ret;
1365 bool long_act;
1366 blk_log_action_t *log_action;
1367
1368 t = te_blk_io_trace(iter->ent);
1369 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1370 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1371 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1372
1373 if (t->action == BLK_TN_MESSAGE) {
1374 ret = log_action(iter, long_act ? "message" : "m");
1375 if (ret)
1376 ret = blk_log_msg(s, iter->ent);
1377 goto out;
1378 }
1379
1380 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1381 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1382 else {
1383 ret = log_action(iter, what2act[what].act[long_act]);
1384 if (ret)
1385 ret = what2act[what].print(s, iter->ent);
1386 }
1387 out:
1388 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1389 }
1390
1391 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1392 int flags, struct trace_event *event)
1393 {
1394 return print_one_line(iter, false);
1395 }
1396
1397 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1398 {
1399 struct trace_seq *s = &iter->seq;
1400 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1401 const int offset = offsetof(struct blk_io_trace, sector);
1402 struct blk_io_trace old = {
1403 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1404 .time = iter->ts,
1405 };
1406
1407 if (!trace_seq_putmem(s, &old, offset))
1408 return 0;
1409 return trace_seq_putmem(s, &t->sector,
1410 sizeof(old) - offset + t->pdu_len);
1411 }
1412
1413 static enum print_line_t
1414 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1415 struct trace_event *event)
1416 {
1417 return blk_trace_synthesize_old_trace(iter) ?
1418 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1419 }
1420
1421 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1422 {
1423 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1424 return TRACE_TYPE_UNHANDLED;
1425
1426 return print_one_line(iter, true);
1427 }
1428
1429 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1430 {
1431 /* don't output context-info for blk_classic output */
1432 if (bit == TRACE_BLK_OPT_CLASSIC) {
1433 if (set)
1434 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1435 else
1436 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1437 }
1438 return 0;
1439 }
1440
1441 static struct tracer blk_tracer __read_mostly = {
1442 .name = "blk",
1443 .init = blk_tracer_init,
1444 .reset = blk_tracer_reset,
1445 .start = blk_tracer_start,
1446 .stop = blk_tracer_stop,
1447 .print_header = blk_tracer_print_header,
1448 .print_line = blk_tracer_print_line,
1449 .flags = &blk_tracer_flags,
1450 .set_flag = blk_tracer_set_flag,
1451 };
1452
1453 static struct trace_event_functions trace_blk_event_funcs = {
1454 .trace = blk_trace_event_print,
1455 .binary = blk_trace_event_print_binary,
1456 };
1457
1458 static struct trace_event trace_blk_event = {
1459 .type = TRACE_BLK,
1460 .funcs = &trace_blk_event_funcs,
1461 };
1462
1463 static int __init init_blk_tracer(void)
1464 {
1465 if (!register_ftrace_event(&trace_blk_event)) {
1466 pr_warning("Warning: could not register block events\n");
1467 return 1;
1468 }
1469
1470 if (register_tracer(&blk_tracer) != 0) {
1471 pr_warning("Warning: could not register the block tracer\n");
1472 unregister_ftrace_event(&trace_blk_event);
1473 return 1;
1474 }
1475
1476 return 0;
1477 }
1478
1479 device_initcall(init_blk_tracer);
1480
1481 static int blk_trace_remove_queue(struct request_queue *q)
1482 {
1483 struct blk_trace *bt;
1484
1485 bt = xchg(&q->blk_trace, NULL);
1486 if (bt == NULL)
1487 return -EINVAL;
1488
1489 if (atomic_dec_and_test(&blk_probes_ref))
1490 blk_unregister_tracepoints();
1491
1492 blk_trace_free(bt);
1493 return 0;
1494 }
1495
1496 /*
1497 * Setup everything required to start tracing
1498 */
1499 static int blk_trace_setup_queue(struct request_queue *q,
1500 struct block_device *bdev)
1501 {
1502 struct blk_trace *old_bt, *bt = NULL;
1503 int ret = -ENOMEM;
1504
1505 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1506 if (!bt)
1507 return -ENOMEM;
1508
1509 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1510 if (!bt->msg_data)
1511 goto free_bt;
1512
1513 bt->dev = bdev->bd_dev;
1514 bt->act_mask = (u16)-1;
1515
1516 blk_trace_setup_lba(bt, bdev);
1517
1518 old_bt = xchg(&q->blk_trace, bt);
1519 if (old_bt != NULL) {
1520 (void)xchg(&q->blk_trace, old_bt);
1521 ret = -EBUSY;
1522 goto free_bt;
1523 }
1524
1525 if (atomic_inc_return(&blk_probes_ref) == 1)
1526 blk_register_tracepoints();
1527 return 0;
1528
1529 free_bt:
1530 blk_trace_free(bt);
1531 return ret;
1532 }
1533
1534 /*
1535 * sysfs interface to enable and configure tracing
1536 */
1537
1538 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1539 struct device_attribute *attr,
1540 char *buf);
1541 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1542 struct device_attribute *attr,
1543 const char *buf, size_t count);
1544 #define BLK_TRACE_DEVICE_ATTR(_name) \
1545 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1546 sysfs_blk_trace_attr_show, \
1547 sysfs_blk_trace_attr_store)
1548
1549 static BLK_TRACE_DEVICE_ATTR(enable);
1550 static BLK_TRACE_DEVICE_ATTR(act_mask);
1551 static BLK_TRACE_DEVICE_ATTR(pid);
1552 static BLK_TRACE_DEVICE_ATTR(start_lba);
1553 static BLK_TRACE_DEVICE_ATTR(end_lba);
1554
1555 static struct attribute *blk_trace_attrs[] = {
1556 &dev_attr_enable.attr,
1557 &dev_attr_act_mask.attr,
1558 &dev_attr_pid.attr,
1559 &dev_attr_start_lba.attr,
1560 &dev_attr_end_lba.attr,
1561 NULL
1562 };
1563
1564 struct attribute_group blk_trace_attr_group = {
1565 .name = "trace",
1566 .attrs = blk_trace_attrs,
1567 };
1568
1569 static const struct {
1570 int mask;
1571 const char *str;
1572 } mask_maps[] = {
1573 { BLK_TC_READ, "read" },
1574 { BLK_TC_WRITE, "write" },
1575 { BLK_TC_BARRIER, "barrier" },
1576 { BLK_TC_SYNC, "sync" },
1577 { BLK_TC_QUEUE, "queue" },
1578 { BLK_TC_REQUEUE, "requeue" },
1579 { BLK_TC_ISSUE, "issue" },
1580 { BLK_TC_COMPLETE, "complete" },
1581 { BLK_TC_FS, "fs" },
1582 { BLK_TC_PC, "pc" },
1583 { BLK_TC_AHEAD, "ahead" },
1584 { BLK_TC_META, "meta" },
1585 { BLK_TC_DISCARD, "discard" },
1586 { BLK_TC_DRV_DATA, "drv_data" },
1587 };
1588
1589 static int blk_trace_str2mask(const char *str)
1590 {
1591 int i;
1592 int mask = 0;
1593 char *buf, *s, *token;
1594
1595 buf = kstrdup(str, GFP_KERNEL);
1596 if (buf == NULL)
1597 return -ENOMEM;
1598 s = strstrip(buf);
1599
1600 while (1) {
1601 token = strsep(&s, ",");
1602 if (token == NULL)
1603 break;
1604
1605 if (*token == '\0')
1606 continue;
1607
1608 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1609 if (strcasecmp(token, mask_maps[i].str) == 0) {
1610 mask |= mask_maps[i].mask;
1611 break;
1612 }
1613 }
1614 if (i == ARRAY_SIZE(mask_maps)) {
1615 mask = -EINVAL;
1616 break;
1617 }
1618 }
1619 kfree(buf);
1620
1621 return mask;
1622 }
1623
1624 static ssize_t blk_trace_mask2str(char *buf, int mask)
1625 {
1626 int i;
1627 char *p = buf;
1628
1629 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1630 if (mask & mask_maps[i].mask) {
1631 p += sprintf(p, "%s%s",
1632 (p == buf) ? "" : ",", mask_maps[i].str);
1633 }
1634 }
1635 *p++ = '\n';
1636
1637 return p - buf;
1638 }
1639
1640 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1641 {
1642 if (bdev->bd_disk == NULL)
1643 return NULL;
1644
1645 return bdev_get_queue(bdev);
1646 }
1647
1648 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1649 struct device_attribute *attr,
1650 char *buf)
1651 {
1652 struct hd_struct *p = dev_to_part(dev);
1653 struct request_queue *q;
1654 struct block_device *bdev;
1655 ssize_t ret = -ENXIO;
1656
1657 bdev = bdget(part_devt(p));
1658 if (bdev == NULL)
1659 goto out;
1660
1661 q = blk_trace_get_queue(bdev);
1662 if (q == NULL)
1663 goto out_bdput;
1664
1665 mutex_lock(&bdev->bd_mutex);
1666
1667 if (attr == &dev_attr_enable) {
1668 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1669 goto out_unlock_bdev;
1670 }
1671
1672 if (q->blk_trace == NULL)
1673 ret = sprintf(buf, "disabled\n");
1674 else if (attr == &dev_attr_act_mask)
1675 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1676 else if (attr == &dev_attr_pid)
1677 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1678 else if (attr == &dev_attr_start_lba)
1679 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1680 else if (attr == &dev_attr_end_lba)
1681 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1682
1683 out_unlock_bdev:
1684 mutex_unlock(&bdev->bd_mutex);
1685 out_bdput:
1686 bdput(bdev);
1687 out:
1688 return ret;
1689 }
1690
1691 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1692 struct device_attribute *attr,
1693 const char *buf, size_t count)
1694 {
1695 struct block_device *bdev;
1696 struct request_queue *q;
1697 struct hd_struct *p;
1698 u64 value;
1699 ssize_t ret = -EINVAL;
1700
1701 if (count == 0)
1702 goto out;
1703
1704 if (attr == &dev_attr_act_mask) {
1705 if (sscanf(buf, "%llx", &value) != 1) {
1706 /* Assume it is a list of trace category names */
1707 ret = blk_trace_str2mask(buf);
1708 if (ret < 0)
1709 goto out;
1710 value = ret;
1711 }
1712 } else if (sscanf(buf, "%llu", &value) != 1)
1713 goto out;
1714
1715 ret = -ENXIO;
1716
1717 p = dev_to_part(dev);
1718 bdev = bdget(part_devt(p));
1719 if (bdev == NULL)
1720 goto out;
1721
1722 q = blk_trace_get_queue(bdev);
1723 if (q == NULL)
1724 goto out_bdput;
1725
1726 mutex_lock(&bdev->bd_mutex);
1727
1728 if (attr == &dev_attr_enable) {
1729 if (value)
1730 ret = blk_trace_setup_queue(q, bdev);
1731 else
1732 ret = blk_trace_remove_queue(q);
1733 goto out_unlock_bdev;
1734 }
1735
1736 ret = 0;
1737 if (q->blk_trace == NULL)
1738 ret = blk_trace_setup_queue(q, bdev);
1739
1740 if (ret == 0) {
1741 if (attr == &dev_attr_act_mask)
1742 q->blk_trace->act_mask = value;
1743 else if (attr == &dev_attr_pid)
1744 q->blk_trace->pid = value;
1745 else if (attr == &dev_attr_start_lba)
1746 q->blk_trace->start_lba = value;
1747 else if (attr == &dev_attr_end_lba)
1748 q->blk_trace->end_lba = value;
1749 }
1750
1751 out_unlock_bdev:
1752 mutex_unlock(&bdev->bd_mutex);
1753 out_bdput:
1754 bdput(bdev);
1755 out:
1756 return ret ? ret : count;
1757 }
1758
1759 int blk_trace_init_sysfs(struct device *dev)
1760 {
1761 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1762 }
1763
1764 void blk_trace_remove_sysfs(struct device *dev)
1765 {
1766 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1767 }
1768
1769 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1770
1771 #ifdef CONFIG_EVENT_TRACING
1772
1773 void blk_dump_cmd(char *buf, struct request *rq)
1774 {
1775 int i, end;
1776 int len = rq->cmd_len;
1777 unsigned char *cmd = rq->cmd;
1778
1779 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1780 buf[0] = '\0';
1781 return;
1782 }
1783
1784 for (end = len - 1; end >= 0; end--)
1785 if (cmd[end])
1786 break;
1787 end++;
1788
1789 for (i = 0; i < len; i++) {
1790 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1791 if (i == end && end != len - 1) {
1792 sprintf(buf, " ..");
1793 break;
1794 }
1795 }
1796 }
1797
1798 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1799 {
1800 int i = 0;
1801
1802 if (rw & WRITE)
1803 rwbs[i++] = 'W';
1804 else if (rw & REQ_DISCARD)
1805 rwbs[i++] = 'D';
1806 else if (bytes)
1807 rwbs[i++] = 'R';
1808 else
1809 rwbs[i++] = 'N';
1810
1811 if (rw & REQ_RAHEAD)
1812 rwbs[i++] = 'A';
1813 if (rw & REQ_SYNC)
1814 rwbs[i++] = 'S';
1815 if (rw & REQ_META)
1816 rwbs[i++] = 'M';
1817 if (rw & REQ_SECURE)
1818 rwbs[i++] = 'E';
1819
1820 rwbs[i] = '\0';
1821 }
1822
1823 #endif /* CONFIG_EVENT_TRACING */
1824
Linux kernel - Deliverables
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