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bus: mvebu-mbus: Factorize Armada 370/XP data structures
[linux-2.6/btrfs-unstable.git] / kernel / trace / blktrace.c
blobb8b8560bfb95af43d36817d743f6218f01ed0edb
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->trace_buffer.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->trace_buffer.buffer;
222 pc = preempt_count();
223 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
224 sizeof(*t) + pdu_len,
225 0, pc);
226 if (!event)
227 return;
228 t = ring_buffer_event_data(event);
229 goto record_it;
230 }
231
232 /*
233 * A word about the locking here - we disable interrupts to reserve
234 * some space in the relay per-cpu buffer, to prevent an irq
235 * from coming in and stepping on our toes.
236 */
237 local_irq_save(flags);
238
239 if (unlikely(tsk->btrace_seq != blktrace_seq))
240 trace_note_tsk(bt, tsk);
241
242 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
243 if (t) {
244 sequence = per_cpu_ptr(bt->sequence, cpu);
245
246 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
247 t->sequence = ++(*sequence);
248 t->time = ktime_to_ns(ktime_get());
249 record_it:
250 /*
251 * These two are not needed in ftrace as they are in the
252 * generic trace_entry, filled by tracing_generic_entry_update,
253 * but for the trace_event->bin() synthesizer benefit we do it
254 * here too.
255 */
256 t->cpu = cpu;
257 t->pid = pid;
258
259 t->sector = sector;
260 t->bytes = bytes;
261 t->action = what;
262 t->device = bt->dev;
263 t->error = error;
264 t->pdu_len = pdu_len;
265
266 if (pdu_len)
267 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
268
269 if (blk_tracer) {
270 trace_buffer_unlock_commit(buffer, event, 0, pc);
271 return;
272 }
273 }
274
275 local_irq_restore(flags);
276 }
277
278 static struct dentry *blk_tree_root;
279 static DEFINE_MUTEX(blk_tree_mutex);
280
281 static void blk_trace_free(struct blk_trace *bt)
282 {
283 debugfs_remove(bt->msg_file);
284 debugfs_remove(bt->dropped_file);
285 relay_close(bt->rchan);
286 debugfs_remove(bt->dir);
287 free_percpu(bt->sequence);
288 free_percpu(bt->msg_data);
289 kfree(bt);
290 }
291
292 static void blk_trace_cleanup(struct blk_trace *bt)
293 {
294 blk_trace_free(bt);
295 if (atomic_dec_and_test(&blk_probes_ref))
296 blk_unregister_tracepoints();
297 }
298
299 int blk_trace_remove(struct request_queue *q)
300 {
301 struct blk_trace *bt;
302
303 bt = xchg(&q->blk_trace, NULL);
304 if (!bt)
305 return -EINVAL;
306
307 if (bt->trace_state != Blktrace_running)
308 blk_trace_cleanup(bt);
309
310 return 0;
311 }
312 EXPORT_SYMBOL_GPL(blk_trace_remove);
313
314 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
315 size_t count, loff_t *ppos)
316 {
317 struct blk_trace *bt = filp->private_data;
318 char buf[16];
319
320 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
321
322 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
323 }
324
325 static const struct file_operations blk_dropped_fops = {
326 .owner = THIS_MODULE,
327 .open = simple_open,
328 .read = blk_dropped_read,
329 .llseek = default_llseek,
330 };
331
332 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
333 size_t count, loff_t *ppos)
334 {
335 char *msg;
336 struct blk_trace *bt;
337
338 if (count >= BLK_TN_MAX_MSG)
339 return -EINVAL;
340
341 msg = kmalloc(count + 1, GFP_KERNEL);
342 if (msg == NULL)
343 return -ENOMEM;
344
345 if (copy_from_user(msg, buffer, count)) {
346 kfree(msg);
347 return -EFAULT;
348 }
349
350 msg[count] = '\0';
351 bt = filp->private_data;
352 __trace_note_message(bt, "%s", msg);
353 kfree(msg);
354
355 return count;
356 }
357
358 static const struct file_operations blk_msg_fops = {
359 .owner = THIS_MODULE,
360 .open = simple_open,
361 .write = blk_msg_write,
362 .llseek = noop_llseek,
363 };
364
365 /*
366 * Keep track of how many times we encountered a full subbuffer, to aid
367 * the user space app in telling how many lost events there were.
368 */
369 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
370 void *prev_subbuf, size_t prev_padding)
371 {
372 struct blk_trace *bt;
373
374 if (!relay_buf_full(buf))
375 return 1;
376
377 bt = buf->chan->private_data;
378 atomic_inc(&bt->dropped);
379 return 0;
380 }
381
382 static int blk_remove_buf_file_callback(struct dentry *dentry)
383 {
384 debugfs_remove(dentry);
385
386 return 0;
387 }
388
389 static struct dentry *blk_create_buf_file_callback(const char *filename,
390 struct dentry *parent,
391 umode_t mode,
392 struct rchan_buf *buf,
393 int *is_global)
394 {
395 return debugfs_create_file(filename, mode, parent, buf,
396 &relay_file_operations);
397 }
398
399 static struct rchan_callbacks blk_relay_callbacks = {
400 .subbuf_start = blk_subbuf_start_callback,
401 .create_buf_file = blk_create_buf_file_callback,
402 .remove_buf_file = blk_remove_buf_file_callback,
403 };
404
405 static void blk_trace_setup_lba(struct blk_trace *bt,
406 struct block_device *bdev)
407 {
408 struct hd_struct *part = NULL;
409
410 if (bdev)
411 part = bdev->bd_part;
412
413 if (part) {
414 bt->start_lba = part->start_sect;
415 bt->end_lba = part->start_sect + part->nr_sects;
416 } else {
417 bt->start_lba = 0;
418 bt->end_lba = -1ULL;
419 }
420 }
421
422 /*
423 * Setup everything required to start tracing
424 */
425 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
426 struct block_device *bdev,
427 struct blk_user_trace_setup *buts)
428 {
429 struct blk_trace *old_bt, *bt = NULL;
430 struct dentry *dir = NULL;
431 int ret, i;
432
433 if (!buts->buf_size || !buts->buf_nr)
434 return -EINVAL;
435
436 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
437 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
438
439 /*
440 * some device names have larger paths - convert the slashes
441 * to underscores for this to work as expected
442 */
443 for (i = 0; i < strlen(buts->name); i++)
444 if (buts->name[i] == '/')
445 buts->name[i] = '_';
446
447 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
448 if (!bt)
449 return -ENOMEM;
450
451 ret = -ENOMEM;
452 bt->sequence = alloc_percpu(unsigned long);
453 if (!bt->sequence)
454 goto err;
455
456 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
457 if (!bt->msg_data)
458 goto err;
459
460 ret = -ENOENT;
461
462 mutex_lock(&blk_tree_mutex);
463 if (!blk_tree_root) {
464 blk_tree_root = debugfs_create_dir("block", NULL);
465 if (!blk_tree_root) {
466 mutex_unlock(&blk_tree_mutex);
467 goto err;
468 }
469 }
470 mutex_unlock(&blk_tree_mutex);
471
472 dir = debugfs_create_dir(buts->name, blk_tree_root);
473
474 if (!dir)
475 goto err;
476
477 bt->dir = dir;
478 bt->dev = dev;
479 atomic_set(&bt->dropped, 0);
480
481 ret = -EIO;
482 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
483 &blk_dropped_fops);
484 if (!bt->dropped_file)
485 goto err;
486
487 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
488 if (!bt->msg_file)
489 goto err;
490
491 bt->rchan = relay_open("trace", dir, buts->buf_size,
492 buts->buf_nr, &blk_relay_callbacks, bt);
493 if (!bt->rchan)
494 goto err;
495
496 bt->act_mask = buts->act_mask;
497 if (!bt->act_mask)
498 bt->act_mask = (u16) -1;
499
500 blk_trace_setup_lba(bt, bdev);
501
502 /* overwrite with user settings */
503 if (buts->start_lba)
504 bt->start_lba = buts->start_lba;
505 if (buts->end_lba)
506 bt->end_lba = buts->end_lba;
507
508 bt->pid = buts->pid;
509 bt->trace_state = Blktrace_setup;
510
511 ret = -EBUSY;
512 old_bt = xchg(&q->blk_trace, bt);
513 if (old_bt) {
514 (void) xchg(&q->blk_trace, old_bt);
515 goto err;
516 }
517
518 if (atomic_inc_return(&blk_probes_ref) == 1)
519 blk_register_tracepoints();
520
521 return 0;
522 err:
523 blk_trace_free(bt);
524 return ret;
525 }
526
527 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
528 struct block_device *bdev,
529 char __user *arg)
530 {
531 struct blk_user_trace_setup buts;
532 int ret;
533
534 ret = copy_from_user(&buts, arg, sizeof(buts));
535 if (ret)
536 return -EFAULT;
537
538 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
539 if (ret)
540 return ret;
541
542 if (copy_to_user(arg, &buts, sizeof(buts))) {
543 blk_trace_remove(q);
544 return -EFAULT;
545 }
546 return 0;
547 }
548 EXPORT_SYMBOL_GPL(blk_trace_setup);
549
550 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
551 static int compat_blk_trace_setup(struct request_queue *q, char *name,
552 dev_t dev, struct block_device *bdev,
553 char __user *arg)
554 {
555 struct blk_user_trace_setup buts;
556 struct compat_blk_user_trace_setup cbuts;
557 int ret;
558
559 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
560 return -EFAULT;
561
562 buts = (struct blk_user_trace_setup) {
563 .act_mask = cbuts.act_mask,
564 .buf_size = cbuts.buf_size,
565 .buf_nr = cbuts.buf_nr,
566 .start_lba = cbuts.start_lba,
567 .end_lba = cbuts.end_lba,
568 .pid = cbuts.pid,
569 };
570 memcpy(&buts.name, &cbuts.name, 32);
571
572 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
573 if (ret)
574 return ret;
575
576 if (copy_to_user(arg, &buts.name, 32)) {
577 blk_trace_remove(q);
578 return -EFAULT;
579 }
580
581 return 0;
582 }
583 #endif
584
585 int blk_trace_startstop(struct request_queue *q, int start)
586 {
587 int ret;
588 struct blk_trace *bt = q->blk_trace;
589
590 if (bt == NULL)
591 return -EINVAL;
592
593 /*
594 * For starting a trace, we can transition from a setup or stopped
595 * trace. For stopping a trace, the state must be running
596 */
597 ret = -EINVAL;
598 if (start) {
599 if (bt->trace_state == Blktrace_setup ||
600 bt->trace_state == Blktrace_stopped) {
601 blktrace_seq++;
602 smp_mb();
603 bt->trace_state = Blktrace_running;
604
605 trace_note_time(bt);
606 ret = 0;
607 }
608 } else {
609 if (bt->trace_state == Blktrace_running) {
610 bt->trace_state = Blktrace_stopped;
611 relay_flush(bt->rchan);
612 ret = 0;
613 }
614 }
615
616 return ret;
617 }
618 EXPORT_SYMBOL_GPL(blk_trace_startstop);
619
620 /**
621 * blk_trace_ioctl: - handle the ioctls associated with tracing
622 * @bdev: the block device
623 * @cmd: the ioctl cmd
624 * @arg: the argument data, if any
625 *
626 **/
627 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
628 {
629 struct request_queue *q;
630 int ret, start = 0;
631 char b[BDEVNAME_SIZE];
632
633 q = bdev_get_queue(bdev);
634 if (!q)
635 return -ENXIO;
636
637 mutex_lock(&bdev->bd_mutex);
638
639 switch (cmd) {
640 case BLKTRACESETUP:
641 bdevname(bdev, b);
642 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
643 break;
644 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
645 case BLKTRACESETUP32:
646 bdevname(bdev, b);
647 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
648 break;
649 #endif
650 case BLKTRACESTART:
651 start = 1;
652 case BLKTRACESTOP:
653 ret = blk_trace_startstop(q, start);
654 break;
655 case BLKTRACETEARDOWN:
656 ret = blk_trace_remove(q);
657 break;
658 default:
659 ret = -ENOTTY;
660 break;
661 }
662
663 mutex_unlock(&bdev->bd_mutex);
664 return ret;
665 }
666
667 /**
668 * blk_trace_shutdown: - stop and cleanup trace structures
669 * @q: the request queue associated with the device
670 *
671 **/
672 void blk_trace_shutdown(struct request_queue *q)
673 {
674 if (q->blk_trace) {
675 blk_trace_startstop(q, 0);
676 blk_trace_remove(q);
677 }
678 }
679
680 /*
681 * blktrace probes
682 */
683
684 /**
685 * blk_add_trace_rq - Add a trace for a request oriented action
686 * @q: queue the io is for
687 * @rq: the source request
688 * @what: the action
689 *
690 * Description:
691 * Records an action against a request. Will log the bio offset + size.
692 *
693 **/
694 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
695 u32 what)
696 {
697 struct blk_trace *bt = q->blk_trace;
698
699 if (likely(!bt))
700 return;
701
702 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
703 what |= BLK_TC_ACT(BLK_TC_PC);
704 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
705 what, rq->errors, rq->cmd_len, rq->cmd);
706 } else {
707 what |= BLK_TC_ACT(BLK_TC_FS);
708 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
709 rq->cmd_flags, what, rq->errors, 0, NULL);
710 }
711 }
712
713 static void blk_add_trace_rq_abort(void *ignore,
714 struct request_queue *q, struct request *rq)
715 {
716 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
717 }
718
719 static void blk_add_trace_rq_insert(void *ignore,
720 struct request_queue *q, struct request *rq)
721 {
722 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
723 }
724
725 static void blk_add_trace_rq_issue(void *ignore,
726 struct request_queue *q, struct request *rq)
727 {
728 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
729 }
730
731 static void blk_add_trace_rq_requeue(void *ignore,
732 struct request_queue *q,
733 struct request *rq)
734 {
735 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
736 }
737
738 static void blk_add_trace_rq_complete(void *ignore,
739 struct request_queue *q,
740 struct request *rq)
741 {
742 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
743 }
744
745 /**
746 * blk_add_trace_bio - Add a trace for a bio oriented action
747 * @q: queue the io is for
748 * @bio: the source bio
749 * @what: the action
750 * @error: error, if any
751 *
752 * Description:
753 * Records an action against a bio. Will log the bio offset + size.
754 *
755 **/
756 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
757 u32 what, int error)
758 {
759 struct blk_trace *bt = q->blk_trace;
760
761 if (likely(!bt))
762 return;
763
764 if (!error && !bio_flagged(bio, BIO_UPTODATE))
765 error = EIO;
766
767 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
768 error, 0, NULL);
769 }
770
771 static void blk_add_trace_bio_bounce(void *ignore,
772 struct request_queue *q, struct bio *bio)
773 {
774 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
775 }
776
777 static void blk_add_trace_bio_complete(void *ignore,
778 struct request_queue *q, struct bio *bio,
779 int error)
780 {
781 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
782 }
783
784 static void blk_add_trace_bio_backmerge(void *ignore,
785 struct request_queue *q,
786 struct request *rq,
787 struct bio *bio)
788 {
789 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
790 }
791
792 static void blk_add_trace_bio_frontmerge(void *ignore,
793 struct request_queue *q,
794 struct request *rq,
795 struct bio *bio)
796 {
797 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
798 }
799
800 static void blk_add_trace_bio_queue(void *ignore,
801 struct request_queue *q, struct bio *bio)
802 {
803 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
804 }
805
806 static void blk_add_trace_getrq(void *ignore,
807 struct request_queue *q,
808 struct bio *bio, int rw)
809 {
810 if (bio)
811 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
812 else {
813 struct blk_trace *bt = q->blk_trace;
814
815 if (bt)
816 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
817 }
818 }
819
820
821 static void blk_add_trace_sleeprq(void *ignore,
822 struct request_queue *q,
823 struct bio *bio, int rw)
824 {
825 if (bio)
826 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
827 else {
828 struct blk_trace *bt = q->blk_trace;
829
830 if (bt)
831 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
832 0, 0, NULL);
833 }
834 }
835
836 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
837 {
838 struct blk_trace *bt = q->blk_trace;
839
840 if (bt)
841 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
842 }
843
844 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
845 unsigned int depth, bool explicit)
846 {
847 struct blk_trace *bt = q->blk_trace;
848
849 if (bt) {
850 __be64 rpdu = cpu_to_be64(depth);
851 u32 what;
852
853 if (explicit)
854 what = BLK_TA_UNPLUG_IO;
855 else
856 what = BLK_TA_UNPLUG_TIMER;
857
858 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
859 }
860 }
861
862 static void blk_add_trace_split(void *ignore,
863 struct request_queue *q, struct bio *bio,
864 unsigned int pdu)
865 {
866 struct blk_trace *bt = q->blk_trace;
867
868 if (bt) {
869 __be64 rpdu = cpu_to_be64(pdu);
870
871 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
872 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
873 sizeof(rpdu), &rpdu);
874 }
875 }
876
877 /**
878 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
879 * @ignore: trace callback data parameter (not used)
880 * @q: queue the io is for
881 * @bio: the source bio
882 * @dev: target device
883 * @from: source sector
884 *
885 * Description:
886 * Device mapper or raid target sometimes need to split a bio because
887 * it spans a stripe (or similar). Add a trace for that action.
888 *
889 **/
890 static void blk_add_trace_bio_remap(void *ignore,
891 struct request_queue *q, struct bio *bio,
892 dev_t dev, sector_t from)
893 {
894 struct blk_trace *bt = q->blk_trace;
895 struct blk_io_trace_remap r;
896
897 if (likely(!bt))
898 return;
899
900 r.device_from = cpu_to_be32(dev);
901 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
902 r.sector_from = cpu_to_be64(from);
903
904 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
905 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
906 sizeof(r), &r);
907 }
908
909 /**
910 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
911 * @ignore: trace callback data parameter (not used)
912 * @q: queue the io is for
913 * @rq: the source request
914 * @dev: target device
915 * @from: source sector
916 *
917 * Description:
918 * Device mapper remaps request to other devices.
919 * Add a trace for that action.
920 *
921 **/
922 static void blk_add_trace_rq_remap(void *ignore,
923 struct request_queue *q,
924 struct request *rq, dev_t dev,
925 sector_t from)
926 {
927 struct blk_trace *bt = q->blk_trace;
928 struct blk_io_trace_remap r;
929
930 if (likely(!bt))
931 return;
932
933 r.device_from = cpu_to_be32(dev);
934 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
935 r.sector_from = cpu_to_be64(from);
936
937 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
938 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
939 sizeof(r), &r);
940 }
941
942 /**
943 * blk_add_driver_data - Add binary message with driver-specific data
944 * @q: queue the io is for
945 * @rq: io request
946 * @data: driver-specific data
947 * @len: length of driver-specific data
948 *
949 * Description:
950 * Some drivers might want to write driver-specific data per request.
951 *
952 **/
953 void blk_add_driver_data(struct request_queue *q,
954 struct request *rq,
955 void *data, size_t len)
956 {
957 struct blk_trace *bt = q->blk_trace;
958
959 if (likely(!bt))
960 return;
961
962 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
963 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
964 BLK_TA_DRV_DATA, rq->errors, len, data);
965 else
966 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
967 BLK_TA_DRV_DATA, rq->errors, len, data);
968 }
969 EXPORT_SYMBOL_GPL(blk_add_driver_data);
970
971 static void blk_register_tracepoints(void)
972 {
973 int ret;
974
975 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
976 WARN_ON(ret);
977 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
978 WARN_ON(ret);
979 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
980 WARN_ON(ret);
981 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
982 WARN_ON(ret);
983 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
984 WARN_ON(ret);
985 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
986 WARN_ON(ret);
987 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
988 WARN_ON(ret);
989 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
990 WARN_ON(ret);
991 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
992 WARN_ON(ret);
993 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
994 WARN_ON(ret);
995 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_split(blk_add_trace_split, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1006 WARN_ON(ret);
1007 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1008 WARN_ON(ret);
1009 }
1010
1011 static void blk_unregister_tracepoints(void)
1012 {
1013 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1014 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1015 unregister_trace_block_split(blk_add_trace_split, NULL);
1016 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1017 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1018 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1019 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1020 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1021 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1022 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1023 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1024 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1025 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1026 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1027 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1028 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1029 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1030
1031 tracepoint_synchronize_unregister();
1032 }
1033
1034 /*
1035 * struct blk_io_tracer formatting routines
1036 */
1037
1038 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1039 {
1040 int i = 0;
1041 int tc = t->action >> BLK_TC_SHIFT;
1042
1043 if (t->action == BLK_TN_MESSAGE) {
1044 rwbs[i++] = 'N';
1045 goto out;
1046 }
1047
1048 if (tc & BLK_TC_FLUSH)
1049 rwbs[i++] = 'F';
1050
1051 if (tc & BLK_TC_DISCARD)
1052 rwbs[i++] = 'D';
1053 else if (tc & BLK_TC_WRITE)
1054 rwbs[i++] = 'W';
1055 else if (t->bytes)
1056 rwbs[i++] = 'R';
1057 else
1058 rwbs[i++] = 'N';
1059
1060 if (tc & BLK_TC_FUA)
1061 rwbs[i++] = 'F';
1062 if (tc & BLK_TC_AHEAD)
1063 rwbs[i++] = 'A';
1064 if (tc & BLK_TC_SYNC)
1065 rwbs[i++] = 'S';
1066 if (tc & BLK_TC_META)
1067 rwbs[i++] = 'M';
1068 out:
1069 rwbs[i] = '\0';
1070 }
1071
1072 static inline
1073 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1074 {
1075 return (const struct blk_io_trace *)ent;
1076 }
1077
1078 static inline const void *pdu_start(const struct trace_entry *ent)
1079 {
1080 return te_blk_io_trace(ent) + 1;
1081 }
1082
1083 static inline u32 t_action(const struct trace_entry *ent)
1084 {
1085 return te_blk_io_trace(ent)->action;
1086 }
1087
1088 static inline u32 t_bytes(const struct trace_entry *ent)
1089 {
1090 return te_blk_io_trace(ent)->bytes;
1091 }
1092
1093 static inline u32 t_sec(const struct trace_entry *ent)
1094 {
1095 return te_blk_io_trace(ent)->bytes >> 9;
1096 }
1097
1098 static inline unsigned long long t_sector(const struct trace_entry *ent)
1099 {
1100 return te_blk_io_trace(ent)->sector;
1101 }
1102
1103 static inline __u16 t_error(const struct trace_entry *ent)
1104 {
1105 return te_blk_io_trace(ent)->error;
1106 }
1107
1108 static __u64 get_pdu_int(const struct trace_entry *ent)
1109 {
1110 const __u64 *val = pdu_start(ent);
1111 return be64_to_cpu(*val);
1112 }
1113
1114 static void get_pdu_remap(const struct trace_entry *ent,
1115 struct blk_io_trace_remap *r)
1116 {
1117 const struct blk_io_trace_remap *__r = pdu_start(ent);
1118 __u64 sector_from = __r->sector_from;
1119
1120 r->device_from = be32_to_cpu(__r->device_from);
1121 r->device_to = be32_to_cpu(__r->device_to);
1122 r->sector_from = be64_to_cpu(sector_from);
1123 }
1124
1125 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1126
1127 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1128 {
1129 char rwbs[RWBS_LEN];
1130 unsigned long long ts = iter->ts;
1131 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1132 unsigned secs = (unsigned long)ts;
1133 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1134
1135 fill_rwbs(rwbs, t);
1136
1137 return trace_seq_printf(&iter->seq,
1138 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1139 MAJOR(t->device), MINOR(t->device), iter->cpu,
1140 secs, nsec_rem, iter->ent->pid, act, rwbs);
1141 }
1142
1143 static int blk_log_action(struct trace_iterator *iter, const char *act)
1144 {
1145 char rwbs[RWBS_LEN];
1146 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1147
1148 fill_rwbs(rwbs, t);
1149 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1150 MAJOR(t->device), MINOR(t->device), act, rwbs);
1151 }
1152
1153 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1154 {
1155 const unsigned char *pdu_buf;
1156 int pdu_len;
1157 int i, end, ret;
1158
1159 pdu_buf = pdu_start(ent);
1160 pdu_len = te_blk_io_trace(ent)->pdu_len;
1161
1162 if (!pdu_len)
1163 return 1;
1164
1165 /* find the last zero that needs to be printed */
1166 for (end = pdu_len - 1; end >= 0; end--)
1167 if (pdu_buf[end])
1168 break;
1169 end++;
1170
1171 if (!trace_seq_putc(s, '('))
1172 return 0;
1173
1174 for (i = 0; i < pdu_len; i++) {
1175
1176 ret = trace_seq_printf(s, "%s%02x",
1177 i == 0 ? "" : " ", pdu_buf[i]);
1178 if (!ret)
1179 return ret;
1180
1181 /*
1182 * stop when the rest is just zeroes and indicate so
1183 * with a ".." appended
1184 */
1185 if (i == end && end != pdu_len - 1)
1186 return trace_seq_puts(s, " ..) ");
1187 }
1188
1189 return trace_seq_puts(s, ") ");
1190 }
1191
1192 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1193 {
1194 char cmd[TASK_COMM_LEN];
1195
1196 trace_find_cmdline(ent->pid, cmd);
1197
1198 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1199 int ret;
1200
1201 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1202 if (!ret)
1203 return 0;
1204 ret = blk_log_dump_pdu(s, ent);
1205 if (!ret)
1206 return 0;
1207 return trace_seq_printf(s, "[%s]\n", cmd);
1208 } else {
1209 if (t_sec(ent))
1210 return trace_seq_printf(s, "%llu + %u [%s]\n",
1211 t_sector(ent), t_sec(ent), cmd);
1212 return trace_seq_printf(s, "[%s]\n", cmd);
1213 }
1214 }
1215
1216 static int blk_log_with_error(struct trace_seq *s,
1217 const struct trace_entry *ent)
1218 {
1219 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1220 int ret;
1221
1222 ret = blk_log_dump_pdu(s, ent);
1223 if (ret)
1224 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1225 return 0;
1226 } else {
1227 if (t_sec(ent))
1228 return trace_seq_printf(s, "%llu + %u [%d]\n",
1229 t_sector(ent),
1230 t_sec(ent), t_error(ent));
1231 return trace_seq_printf(s, "%llu [%d]\n",
1232 t_sector(ent), t_error(ent));
1233 }
1234 }
1235
1236 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1237 {
1238 struct blk_io_trace_remap r = { .device_from = 0, };
1239
1240 get_pdu_remap(ent, &r);
1241 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1242 t_sector(ent), t_sec(ent),
1243 MAJOR(r.device_from), MINOR(r.device_from),
1244 (unsigned long long)r.sector_from);
1245 }
1246
1247 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1248 {
1249 char cmd[TASK_COMM_LEN];
1250
1251 trace_find_cmdline(ent->pid, cmd);
1252
1253 return trace_seq_printf(s, "[%s]\n", cmd);
1254 }
1255
1256 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1257 {
1258 char cmd[TASK_COMM_LEN];
1259
1260 trace_find_cmdline(ent->pid, cmd);
1261
1262 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1263 }
1264
1265 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1266 {
1267 char cmd[TASK_COMM_LEN];
1268
1269 trace_find_cmdline(ent->pid, cmd);
1270
1271 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1272 get_pdu_int(ent), cmd);
1273 }
1274
1275 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1276 {
1277 int ret;
1278 const struct blk_io_trace *t = te_blk_io_trace(ent);
1279
1280 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1281 if (ret)
1282 return trace_seq_putc(s, '\n');
1283 return ret;
1284 }
1285
1286 /*
1287 * struct tracer operations
1288 */
1289
1290 static void blk_tracer_print_header(struct seq_file *m)
1291 {
1292 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1293 return;
1294 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1295 "# | | | | | |\n");
1296 }
1297
1298 static void blk_tracer_start(struct trace_array *tr)
1299 {
1300 blk_tracer_enabled = true;
1301 }
1302
1303 static int blk_tracer_init(struct trace_array *tr)
1304 {
1305 blk_tr = tr;
1306 blk_tracer_start(tr);
1307 return 0;
1308 }
1309
1310 static void blk_tracer_stop(struct trace_array *tr)
1311 {
1312 blk_tracer_enabled = false;
1313 }
1314
1315 static void blk_tracer_reset(struct trace_array *tr)
1316 {
1317 blk_tracer_stop(tr);
1318 }
1319
1320 static const struct {
1321 const char *act[2];
1322 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1323 } what2act[] = {
1324 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1325 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1326 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1327 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1328 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1329 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1330 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1331 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1332 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1333 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1334 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1335 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1336 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1337 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1338 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1339 };
1340
1341 static enum print_line_t print_one_line(struct trace_iterator *iter,
1342 bool classic)
1343 {
1344 struct trace_seq *s = &iter->seq;
1345 const struct blk_io_trace *t;
1346 u16 what;
1347 int ret;
1348 bool long_act;
1349 blk_log_action_t *log_action;
1350
1351 t = te_blk_io_trace(iter->ent);
1352 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1353 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1354 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1355
1356 if (t->action == BLK_TN_MESSAGE) {
1357 ret = log_action(iter, long_act ? "message" : "m");
1358 if (ret)
1359 ret = blk_log_msg(s, iter->ent);
1360 goto out;
1361 }
1362
1363 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1364 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1365 else {
1366 ret = log_action(iter, what2act[what].act[long_act]);
1367 if (ret)
1368 ret = what2act[what].print(s, iter->ent);
1369 }
1370 out:
1371 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1372 }
1373
1374 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1375 int flags, struct trace_event *event)
1376 {
1377 return print_one_line(iter, false);
1378 }
1379
1380 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1381 {
1382 struct trace_seq *s = &iter->seq;
1383 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1384 const int offset = offsetof(struct blk_io_trace, sector);
1385 struct blk_io_trace old = {
1386 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1387 .time = iter->ts,
1388 };
1389
1390 if (!trace_seq_putmem(s, &old, offset))
1391 return 0;
1392 return trace_seq_putmem(s, &t->sector,
1393 sizeof(old) - offset + t->pdu_len);
1394 }
1395
1396 static enum print_line_t
1397 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1398 struct trace_event *event)
1399 {
1400 return blk_trace_synthesize_old_trace(iter) ?
1401 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1402 }
1403
1404 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1405 {
1406 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1407 return TRACE_TYPE_UNHANDLED;
1408
1409 return print_one_line(iter, true);
1410 }
1411
1412 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1413 {
1414 /* don't output context-info for blk_classic output */
1415 if (bit == TRACE_BLK_OPT_CLASSIC) {
1416 if (set)
1417 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1418 else
1419 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1420 }
1421 return 0;
1422 }
1423
1424 static struct tracer blk_tracer __read_mostly = {
1425 .name = "blk",
1426 .init = blk_tracer_init,
1427 .reset = blk_tracer_reset,
1428 .start = blk_tracer_start,
1429 .stop = blk_tracer_stop,
1430 .print_header = blk_tracer_print_header,
1431 .print_line = blk_tracer_print_line,
1432 .flags = &blk_tracer_flags,
1433 .set_flag = blk_tracer_set_flag,
1434 };
1435
1436 static struct trace_event_functions trace_blk_event_funcs = {
1437 .trace = blk_trace_event_print,
1438 .binary = blk_trace_event_print_binary,
1439 };
1440
1441 static struct trace_event trace_blk_event = {
1442 .type = TRACE_BLK,
1443 .funcs = &trace_blk_event_funcs,
1444 };
1445
1446 static int __init init_blk_tracer(void)
1447 {
1448 if (!register_ftrace_event(&trace_blk_event)) {
1449 pr_warning("Warning: could not register block events\n");
1450 return 1;
1451 }
1452
1453 if (register_tracer(&blk_tracer) != 0) {
1454 pr_warning("Warning: could not register the block tracer\n");
1455 unregister_ftrace_event(&trace_blk_event);
1456 return 1;
1457 }
1458
1459 return 0;
1460 }
1461
1462 device_initcall(init_blk_tracer);
1463
1464 static int blk_trace_remove_queue(struct request_queue *q)
1465 {
1466 struct blk_trace *bt;
1467
1468 bt = xchg(&q->blk_trace, NULL);
1469 if (bt == NULL)
1470 return -EINVAL;
1471
1472 if (atomic_dec_and_test(&blk_probes_ref))
1473 blk_unregister_tracepoints();
1474
1475 blk_trace_free(bt);
1476 return 0;
1477 }
1478
1479 /*
1480 * Setup everything required to start tracing
1481 */
1482 static int blk_trace_setup_queue(struct request_queue *q,
1483 struct block_device *bdev)
1484 {
1485 struct blk_trace *old_bt, *bt = NULL;
1486 int ret = -ENOMEM;
1487
1488 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1489 if (!bt)
1490 return -ENOMEM;
1491
1492 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1493 if (!bt->msg_data)
1494 goto free_bt;
1495
1496 bt->dev = bdev->bd_dev;
1497 bt->act_mask = (u16)-1;
1498
1499 blk_trace_setup_lba(bt, bdev);
1500
1501 old_bt = xchg(&q->blk_trace, bt);
1502 if (old_bt != NULL) {
1503 (void)xchg(&q->blk_trace, old_bt);
1504 ret = -EBUSY;
1505 goto free_bt;
1506 }
1507
1508 if (atomic_inc_return(&blk_probes_ref) == 1)
1509 blk_register_tracepoints();
1510 return 0;
1511
1512 free_bt:
1513 blk_trace_free(bt);
1514 return ret;
1515 }
1516
1517 /*
1518 * sysfs interface to enable and configure tracing
1519 */
1520
1521 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1522 struct device_attribute *attr,
1523 char *buf);
1524 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1525 struct device_attribute *attr,
1526 const char *buf, size_t count);
1527 #define BLK_TRACE_DEVICE_ATTR(_name) \
1528 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1529 sysfs_blk_trace_attr_show, \
1530 sysfs_blk_trace_attr_store)
1531
1532 static BLK_TRACE_DEVICE_ATTR(enable);
1533 static BLK_TRACE_DEVICE_ATTR(act_mask);
1534 static BLK_TRACE_DEVICE_ATTR(pid);
1535 static BLK_TRACE_DEVICE_ATTR(start_lba);
1536 static BLK_TRACE_DEVICE_ATTR(end_lba);
1537
1538 static struct attribute *blk_trace_attrs[] = {
1539 &dev_attr_enable.attr,
1540 &dev_attr_act_mask.attr,
1541 &dev_attr_pid.attr,
1542 &dev_attr_start_lba.attr,
1543 &dev_attr_end_lba.attr,
1544 NULL
1545 };
1546
1547 struct attribute_group blk_trace_attr_group = {
1548 .name = "trace",
1549 .attrs = blk_trace_attrs,
1550 };
1551
1552 static const struct {
1553 int mask;
1554 const char *str;
1555 } mask_maps[] = {
1556 { BLK_TC_READ, "read" },
1557 { BLK_TC_WRITE, "write" },
1558 { BLK_TC_FLUSH, "flush" },
1559 { BLK_TC_SYNC, "sync" },
1560 { BLK_TC_QUEUE, "queue" },
1561 { BLK_TC_REQUEUE, "requeue" },
1562 { BLK_TC_ISSUE, "issue" },
1563 { BLK_TC_COMPLETE, "complete" },
1564 { BLK_TC_FS, "fs" },
1565 { BLK_TC_PC, "pc" },
1566 { BLK_TC_AHEAD, "ahead" },
1567 { BLK_TC_META, "meta" },
1568 { BLK_TC_DISCARD, "discard" },
1569 { BLK_TC_DRV_DATA, "drv_data" },
1570 { BLK_TC_FUA, "fua" },
1571 };
1572
1573 static int blk_trace_str2mask(const char *str)
1574 {
1575 int i;
1576 int mask = 0;
1577 char *buf, *s, *token;
1578
1579 buf = kstrdup(str, GFP_KERNEL);
1580 if (buf == NULL)
1581 return -ENOMEM;
1582 s = strstrip(buf);
1583
1584 while (1) {
1585 token = strsep(&s, ",");
1586 if (token == NULL)
1587 break;
1588
1589 if (*token == '\0')
1590 continue;
1591
1592 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1593 if (strcasecmp(token, mask_maps[i].str) == 0) {
1594 mask |= mask_maps[i].mask;
1595 break;
1596 }
1597 }
1598 if (i == ARRAY_SIZE(mask_maps)) {
1599 mask = -EINVAL;
1600 break;
1601 }
1602 }
1603 kfree(buf);
1604
1605 return mask;
1606 }
1607
1608 static ssize_t blk_trace_mask2str(char *buf, int mask)
1609 {
1610 int i;
1611 char *p = buf;
1612
1613 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1614 if (mask & mask_maps[i].mask) {
1615 p += sprintf(p, "%s%s",
1616 (p == buf) ? "" : ",", mask_maps[i].str);
1617 }
1618 }
1619 *p++ = '\n';
1620
1621 return p - buf;
1622 }
1623
1624 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1625 {
1626 if (bdev->bd_disk == NULL)
1627 return NULL;
1628
1629 return bdev_get_queue(bdev);
1630 }
1631
1632 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1633 struct device_attribute *attr,
1634 char *buf)
1635 {
1636 struct hd_struct *p = dev_to_part(dev);
1637 struct request_queue *q;
1638 struct block_device *bdev;
1639 ssize_t ret = -ENXIO;
1640
1641 bdev = bdget(part_devt(p));
1642 if (bdev == NULL)
1643 goto out;
1644
1645 q = blk_trace_get_queue(bdev);
1646 if (q == NULL)
1647 goto out_bdput;
1648
1649 mutex_lock(&bdev->bd_mutex);
1650
1651 if (attr == &dev_attr_enable) {
1652 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1653 goto out_unlock_bdev;
1654 }
1655
1656 if (q->blk_trace == NULL)
1657 ret = sprintf(buf, "disabled\n");
1658 else if (attr == &dev_attr_act_mask)
1659 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1660 else if (attr == &dev_attr_pid)
1661 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1662 else if (attr == &dev_attr_start_lba)
1663 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1664 else if (attr == &dev_attr_end_lba)
1665 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1666
1667 out_unlock_bdev:
1668 mutex_unlock(&bdev->bd_mutex);
1669 out_bdput:
1670 bdput(bdev);
1671 out:
1672 return ret;
1673 }
1674
1675 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1676 struct device_attribute *attr,
1677 const char *buf, size_t count)
1678 {
1679 struct block_device *bdev;
1680 struct request_queue *q;
1681 struct hd_struct *p;
1682 u64 value;
1683 ssize_t ret = -EINVAL;
1684
1685 if (count == 0)
1686 goto out;
1687
1688 if (attr == &dev_attr_act_mask) {
1689 if (sscanf(buf, "%llx", &value) != 1) {
1690 /* Assume it is a list of trace category names */
1691 ret = blk_trace_str2mask(buf);
1692 if (ret < 0)
1693 goto out;
1694 value = ret;
1695 }
1696 } else if (sscanf(buf, "%llu", &value) != 1)
1697 goto out;
1698
1699 ret = -ENXIO;
1700
1701 p = dev_to_part(dev);
1702 bdev = bdget(part_devt(p));
1703 if (bdev == NULL)
1704 goto out;
1705
1706 q = blk_trace_get_queue(bdev);
1707 if (q == NULL)
1708 goto out_bdput;
1709
1710 mutex_lock(&bdev->bd_mutex);
1711
1712 if (attr == &dev_attr_enable) {
1713 if (value)
1714 ret = blk_trace_setup_queue(q, bdev);
1715 else
1716 ret = blk_trace_remove_queue(q);
1717 goto out_unlock_bdev;
1718 }
1719
1720 ret = 0;
1721 if (q->blk_trace == NULL)
1722 ret = blk_trace_setup_queue(q, bdev);
1723
1724 if (ret == 0) {
1725 if (attr == &dev_attr_act_mask)
1726 q->blk_trace->act_mask = value;
1727 else if (attr == &dev_attr_pid)
1728 q->blk_trace->pid = value;
1729 else if (attr == &dev_attr_start_lba)
1730 q->blk_trace->start_lba = value;
1731 else if (attr == &dev_attr_end_lba)
1732 q->blk_trace->end_lba = value;
1733 }
1734
1735 out_unlock_bdev:
1736 mutex_unlock(&bdev->bd_mutex);
1737 out_bdput:
1738 bdput(bdev);
1739 out:
1740 return ret ? ret : count;
1741 }
1742
1743 int blk_trace_init_sysfs(struct device *dev)
1744 {
1745 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1746 }
1747
1748 void blk_trace_remove_sysfs(struct device *dev)
1749 {
1750 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1751 }
1752
1753 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1754
1755 #ifdef CONFIG_EVENT_TRACING
1756
1757 void blk_dump_cmd(char *buf, struct request *rq)
1758 {
1759 int i, end;
1760 int len = rq->cmd_len;
1761 unsigned char *cmd = rq->cmd;
1762
1763 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1764 buf[0] = '\0';
1765 return;
1766 }
1767
1768 for (end = len - 1; end >= 0; end--)
1769 if (cmd[end])
1770 break;
1771 end++;
1772
1773 for (i = 0; i < len; i++) {
1774 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1775 if (i == end && end != len - 1) {
1776 sprintf(buf, " ..");
1777 break;
1778 }
1779 }
1780 }
1781
1782 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1783 {
1784 int i = 0;
1785
1786 if (rw & REQ_FLUSH)
1787 rwbs[i++] = 'F';
1788
1789 if (rw & WRITE)
1790 rwbs[i++] = 'W';
1791 else if (rw & REQ_DISCARD)
1792 rwbs[i++] = 'D';
1793 else if (bytes)
1794 rwbs[i++] = 'R';
1795 else
1796 rwbs[i++] = 'N';
1797
1798 if (rw & REQ_FUA)
1799 rwbs[i++] = 'F';
1800 if (rw & REQ_RAHEAD)
1801 rwbs[i++] = 'A';
1802 if (rw & REQ_SYNC)
1803 rwbs[i++] = 'S';
1804 if (rw & REQ_META)
1805 rwbs[i++] = 'M';
1806 if (rw & REQ_SECURE)
1807 rwbs[i++] = 'E';
1808
1809 rwbs[i] = '\0';
1810 }
1811 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1812
1813 #endif /* CONFIG_EVENT_TRACING */
1814
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