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x86/xen: resume timer irqs early
[linux/fpc-iii.git] / kernel / trace / blktrace.c
blobe0e5f73db5a49ad0edb3ad0e382a719d5686ba72
1 /*
2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
16 *
17 */
18 #include <linux/kernel.h>
19 #include <linux/blkdev.h>
20 #include <linux/blktrace_api.h>
21 #include <linux/percpu.h>
22 #include <linux/init.h>
23 #include <linux/mutex.h>
24 #include <linux/slab.h>
25 #include <linux/debugfs.h>
26 #include <linux/export.h>
27 #include <linux/time.h>
28 #include <linux/uaccess.h>
29 #include <linux/list.h>
30
31 #include <trace/events/block.h>
32
33 #include "trace_output.h"
34
35 #ifdef CONFIG_BLK_DEV_IO_TRACE
36
37 static unsigned int blktrace_seq __read_mostly = 1;
38
39 static struct trace_array *blk_tr;
40 static bool blk_tracer_enabled __read_mostly;
41
42 static LIST_HEAD(running_trace_list);
43 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
44
45 /* Select an alternative, minimalistic output than the original one */
46 #define TRACE_BLK_OPT_CLASSIC 0x1
47
48 static struct tracer_opt blk_tracer_opts[] = {
49 /* Default disable the minimalistic output */
50 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
51 { }
52 };
53
54 static struct tracer_flags blk_tracer_flags = {
55 .val = 0,
56 .opts = blk_tracer_opts,
57 };
58
59 /* Global reference count of probes */
60 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
61
62 static void blk_register_tracepoints(void);
63 static void blk_unregister_tracepoints(void);
64
65 /*
66 * Send out a notify message.
67 */
68 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
69 const void *data, size_t len)
70 {
71 struct blk_io_trace *t;
72 struct ring_buffer_event *event = NULL;
73 struct ring_buffer *buffer = NULL;
74 int pc = 0;
75 int cpu = smp_processor_id();
76 bool blk_tracer = blk_tracer_enabled;
77
78 if (blk_tracer) {
79 buffer = blk_tr->trace_buffer.buffer;
80 pc = preempt_count();
81 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
82 sizeof(*t) + len,
83 0, pc);
84 if (!event)
85 return;
86 t = ring_buffer_event_data(event);
87 goto record_it;
88 }
89
90 if (!bt->rchan)
91 return;
92
93 t = relay_reserve(bt->rchan, sizeof(*t) + len);
94 if (t) {
95 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
96 t->time = ktime_to_ns(ktime_get());
97 record_it:
98 t->device = bt->dev;
99 t->action = action;
100 t->pid = pid;
101 t->cpu = cpu;
102 t->pdu_len = len;
103 memcpy((void *) t + sizeof(*t), data, len);
104
105 if (blk_tracer)
106 trace_buffer_unlock_commit(buffer, event, 0, pc);
107 }
108 }
109
110 /*
111 * Send out a notify for this process, if we haven't done so since a trace
112 * started
113 */
114 static void trace_note_tsk(struct task_struct *tsk)
115 {
116 unsigned long flags;
117 struct blk_trace *bt;
118
119 tsk->btrace_seq = blktrace_seq;
120 spin_lock_irqsave(&running_trace_lock, flags);
121 list_for_each_entry(bt, &running_trace_list, running_list) {
122 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
123 sizeof(tsk->comm));
124 }
125 spin_unlock_irqrestore(&running_trace_lock, flags);
126 }
127
128 static void trace_note_time(struct blk_trace *bt)
129 {
130 struct timespec now;
131 unsigned long flags;
132 u32 words[2];
133
134 getnstimeofday(&now);
135 words[0] = now.tv_sec;
136 words[1] = now.tv_nsec;
137
138 local_irq_save(flags);
139 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
140 local_irq_restore(flags);
141 }
142
143 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
144 {
145 int n;
146 va_list args;
147 unsigned long flags;
148 char *buf;
149
150 if (unlikely(bt->trace_state != Blktrace_running &&
151 !blk_tracer_enabled))
152 return;
153
154 /*
155 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
156 * message to the trace.
157 */
158 if (!(bt->act_mask & BLK_TC_NOTIFY))
159 return;
160
161 local_irq_save(flags);
162 buf = this_cpu_ptr(bt->msg_data);
163 va_start(args, fmt);
164 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
165 va_end(args);
166
167 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
168 local_irq_restore(flags);
169 }
170 EXPORT_SYMBOL_GPL(__trace_note_message);
171
172 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
173 pid_t pid)
174 {
175 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
176 return 1;
177 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
178 return 1;
179 if (bt->pid && pid != bt->pid)
180 return 1;
181
182 return 0;
183 }
184
185 /*
186 * Data direction bit lookup
187 */
188 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
189 BLK_TC_ACT(BLK_TC_WRITE) };
190
191 #define BLK_TC_RAHEAD BLK_TC_AHEAD
192
193 /* The ilog2() calls fall out because they're constant */
194 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
195 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
196
197 /*
198 * The worker for the various blk_add_trace*() types. Fills out a
199 * blk_io_trace structure and places it in a per-cpu subbuffer.
200 */
201 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
202 int rw, u32 what, int error, int pdu_len, void *pdu_data)
203 {
204 struct task_struct *tsk = current;
205 struct ring_buffer_event *event = NULL;
206 struct ring_buffer *buffer = NULL;
207 struct blk_io_trace *t;
208 unsigned long flags = 0;
209 unsigned long *sequence;
210 pid_t pid;
211 int cpu, pc = 0;
212 bool blk_tracer = blk_tracer_enabled;
213
214 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
215 return;
216
217 what |= ddir_act[rw & WRITE];
218 what |= MASK_TC_BIT(rw, SYNC);
219 what |= MASK_TC_BIT(rw, RAHEAD);
220 what |= MASK_TC_BIT(rw, META);
221 what |= MASK_TC_BIT(rw, DISCARD);
222 what |= MASK_TC_BIT(rw, FLUSH);
223 what |= MASK_TC_BIT(rw, FUA);
224
225 pid = tsk->pid;
226 if (act_log_check(bt, what, sector, pid))
227 return;
228 cpu = raw_smp_processor_id();
229
230 if (blk_tracer) {
231 tracing_record_cmdline(current);
232
233 buffer = blk_tr->trace_buffer.buffer;
234 pc = preempt_count();
235 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
236 sizeof(*t) + pdu_len,
237 0, pc);
238 if (!event)
239 return;
240 t = ring_buffer_event_data(event);
241 goto record_it;
242 }
243
244 if (unlikely(tsk->btrace_seq != blktrace_seq))
245 trace_note_tsk(tsk);
246
247 /*
248 * A word about the locking here - we disable interrupts to reserve
249 * some space in the relay per-cpu buffer, to prevent an irq
250 * from coming in and stepping on our toes.
251 */
252 local_irq_save(flags);
253 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
254 if (t) {
255 sequence = per_cpu_ptr(bt->sequence, cpu);
256
257 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
258 t->sequence = ++(*sequence);
259 t->time = ktime_to_ns(ktime_get());
260 record_it:
261 /*
262 * These two are not needed in ftrace as they are in the
263 * generic trace_entry, filled by tracing_generic_entry_update,
264 * but for the trace_event->bin() synthesizer benefit we do it
265 * here too.
266 */
267 t->cpu = cpu;
268 t->pid = pid;
269
270 t->sector = sector;
271 t->bytes = bytes;
272 t->action = what;
273 t->device = bt->dev;
274 t->error = error;
275 t->pdu_len = pdu_len;
276
277 if (pdu_len)
278 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
279
280 if (blk_tracer) {
281 trace_buffer_unlock_commit(buffer, event, 0, pc);
282 return;
283 }
284 }
285
286 local_irq_restore(flags);
287 }
288
289 static struct dentry *blk_tree_root;
290 static DEFINE_MUTEX(blk_tree_mutex);
291
292 static void blk_trace_free(struct blk_trace *bt)
293 {
294 debugfs_remove(bt->msg_file);
295 debugfs_remove(bt->dropped_file);
296 relay_close(bt->rchan);
297 debugfs_remove(bt->dir);
298 free_percpu(bt->sequence);
299 free_percpu(bt->msg_data);
300 kfree(bt);
301 }
302
303 static void blk_trace_cleanup(struct blk_trace *bt)
304 {
305 blk_trace_free(bt);
306 if (atomic_dec_and_test(&blk_probes_ref))
307 blk_unregister_tracepoints();
308 }
309
310 int blk_trace_remove(struct request_queue *q)
311 {
312 struct blk_trace *bt;
313
314 bt = xchg(&q->blk_trace, NULL);
315 if (!bt)
316 return -EINVAL;
317
318 if (bt->trace_state != Blktrace_running)
319 blk_trace_cleanup(bt);
320
321 return 0;
322 }
323 EXPORT_SYMBOL_GPL(blk_trace_remove);
324
325 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
326 size_t count, loff_t *ppos)
327 {
328 struct blk_trace *bt = filp->private_data;
329 char buf[16];
330
331 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
332
333 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
334 }
335
336 static const struct file_operations blk_dropped_fops = {
337 .owner = THIS_MODULE,
338 .open = simple_open,
339 .read = blk_dropped_read,
340 .llseek = default_llseek,
341 };
342
343 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
344 size_t count, loff_t *ppos)
345 {
346 char *msg;
347 struct blk_trace *bt;
348
349 if (count >= BLK_TN_MAX_MSG)
350 return -EINVAL;
351
352 msg = kmalloc(count + 1, GFP_KERNEL);
353 if (msg == NULL)
354 return -ENOMEM;
355
356 if (copy_from_user(msg, buffer, count)) {
357 kfree(msg);
358 return -EFAULT;
359 }
360
361 msg[count] = '\0';
362 bt = filp->private_data;
363 __trace_note_message(bt, "%s", msg);
364 kfree(msg);
365
366 return count;
367 }
368
369 static const struct file_operations blk_msg_fops = {
370 .owner = THIS_MODULE,
371 .open = simple_open,
372 .write = blk_msg_write,
373 .llseek = noop_llseek,
374 };
375
376 /*
377 * Keep track of how many times we encountered a full subbuffer, to aid
378 * the user space app in telling how many lost events there were.
379 */
380 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
381 void *prev_subbuf, size_t prev_padding)
382 {
383 struct blk_trace *bt;
384
385 if (!relay_buf_full(buf))
386 return 1;
387
388 bt = buf->chan->private_data;
389 atomic_inc(&bt->dropped);
390 return 0;
391 }
392
393 static int blk_remove_buf_file_callback(struct dentry *dentry)
394 {
395 debugfs_remove(dentry);
396
397 return 0;
398 }
399
400 static struct dentry *blk_create_buf_file_callback(const char *filename,
401 struct dentry *parent,
402 umode_t mode,
403 struct rchan_buf *buf,
404 int *is_global)
405 {
406 return debugfs_create_file(filename, mode, parent, buf,
407 &relay_file_operations);
408 }
409
410 static struct rchan_callbacks blk_relay_callbacks = {
411 .subbuf_start = blk_subbuf_start_callback,
412 .create_buf_file = blk_create_buf_file_callback,
413 .remove_buf_file = blk_remove_buf_file_callback,
414 };
415
416 static void blk_trace_setup_lba(struct blk_trace *bt,
417 struct block_device *bdev)
418 {
419 struct hd_struct *part = NULL;
420
421 if (bdev)
422 part = bdev->bd_part;
423
424 if (part) {
425 bt->start_lba = part->start_sect;
426 bt->end_lba = part->start_sect + part->nr_sects;
427 } else {
428 bt->start_lba = 0;
429 bt->end_lba = -1ULL;
430 }
431 }
432
433 /*
434 * Setup everything required to start tracing
435 */
436 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
437 struct block_device *bdev,
438 struct blk_user_trace_setup *buts)
439 {
440 struct blk_trace *old_bt, *bt = NULL;
441 struct dentry *dir = NULL;
442 int ret, 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 INIT_LIST_HEAD(&bt->running_list);
492
493 ret = -EIO;
494 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
495 &blk_dropped_fops);
496 if (!bt->dropped_file)
497 goto err;
498
499 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
500 if (!bt->msg_file)
501 goto err;
502
503 bt->rchan = relay_open("trace", dir, buts->buf_size,
504 buts->buf_nr, &blk_relay_callbacks, bt);
505 if (!bt->rchan)
506 goto err;
507
508 bt->act_mask = buts->act_mask;
509 if (!bt->act_mask)
510 bt->act_mask = (u16) -1;
511
512 blk_trace_setup_lba(bt, bdev);
513
514 /* overwrite with user settings */
515 if (buts->start_lba)
516 bt->start_lba = buts->start_lba;
517 if (buts->end_lba)
518 bt->end_lba = buts->end_lba;
519
520 bt->pid = buts->pid;
521 bt->trace_state = Blktrace_setup;
522
523 ret = -EBUSY;
524 old_bt = xchg(&q->blk_trace, bt);
525 if (old_bt) {
526 (void) xchg(&q->blk_trace, old_bt);
527 goto err;
528 }
529
530 if (atomic_inc_return(&blk_probes_ref) == 1)
531 blk_register_tracepoints();
532
533 return 0;
534 err:
535 blk_trace_free(bt);
536 return ret;
537 }
538
539 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
540 struct block_device *bdev,
541 char __user *arg)
542 {
543 struct blk_user_trace_setup buts;
544 int ret;
545
546 ret = copy_from_user(&buts, arg, sizeof(buts));
547 if (ret)
548 return -EFAULT;
549
550 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
551 if (ret)
552 return ret;
553
554 if (copy_to_user(arg, &buts, sizeof(buts))) {
555 blk_trace_remove(q);
556 return -EFAULT;
557 }
558 return 0;
559 }
560 EXPORT_SYMBOL_GPL(blk_trace_setup);
561
562 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
563 static int compat_blk_trace_setup(struct request_queue *q, char *name,
564 dev_t dev, struct block_device *bdev,
565 char __user *arg)
566 {
567 struct blk_user_trace_setup buts;
568 struct compat_blk_user_trace_setup cbuts;
569 int ret;
570
571 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
572 return -EFAULT;
573
574 buts = (struct blk_user_trace_setup) {
575 .act_mask = cbuts.act_mask,
576 .buf_size = cbuts.buf_size,
577 .buf_nr = cbuts.buf_nr,
578 .start_lba = cbuts.start_lba,
579 .end_lba = cbuts.end_lba,
580 .pid = cbuts.pid,
581 };
582 memcpy(&buts.name, &cbuts.name, 32);
583
584 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
585 if (ret)
586 return ret;
587
588 if (copy_to_user(arg, &buts.name, 32)) {
589 blk_trace_remove(q);
590 return -EFAULT;
591 }
592
593 return 0;
594 }
595 #endif
596
597 int blk_trace_startstop(struct request_queue *q, int start)
598 {
599 int ret;
600 struct blk_trace *bt = q->blk_trace;
601
602 if (bt == NULL)
603 return -EINVAL;
604
605 /*
606 * For starting a trace, we can transition from a setup or stopped
607 * trace. For stopping a trace, the state must be running
608 */
609 ret = -EINVAL;
610 if (start) {
611 if (bt->trace_state == Blktrace_setup ||
612 bt->trace_state == Blktrace_stopped) {
613 blktrace_seq++;
614 smp_mb();
615 bt->trace_state = Blktrace_running;
616 spin_lock_irq(&running_trace_lock);
617 list_add(&bt->running_list, &running_trace_list);
618 spin_unlock_irq(&running_trace_lock);
619
620 trace_note_time(bt);
621 ret = 0;
622 }
623 } else {
624 if (bt->trace_state == Blktrace_running) {
625 bt->trace_state = Blktrace_stopped;
626 spin_lock_irq(&running_trace_lock);
627 list_del_init(&bt->running_list);
628 spin_unlock_irq(&running_trace_lock);
629 relay_flush(bt->rchan);
630 ret = 0;
631 }
632 }
633
634 return ret;
635 }
636 EXPORT_SYMBOL_GPL(blk_trace_startstop);
637
638 /**
639 * blk_trace_ioctl: - handle the ioctls associated with tracing
640 * @bdev: the block device
641 * @cmd: the ioctl cmd
642 * @arg: the argument data, if any
643 *
644 **/
645 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
646 {
647 struct request_queue *q;
648 int ret, start = 0;
649 char b[BDEVNAME_SIZE];
650
651 q = bdev_get_queue(bdev);
652 if (!q)
653 return -ENXIO;
654
655 mutex_lock(&bdev->bd_mutex);
656
657 switch (cmd) {
658 case BLKTRACESETUP:
659 bdevname(bdev, b);
660 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
661 break;
662 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
663 case BLKTRACESETUP32:
664 bdevname(bdev, b);
665 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
666 break;
667 #endif
668 case BLKTRACESTART:
669 start = 1;
670 case BLKTRACESTOP:
671 ret = blk_trace_startstop(q, start);
672 break;
673 case BLKTRACETEARDOWN:
674 ret = blk_trace_remove(q);
675 break;
676 default:
677 ret = -ENOTTY;
678 break;
679 }
680
681 mutex_unlock(&bdev->bd_mutex);
682 return ret;
683 }
684
685 /**
686 * blk_trace_shutdown: - stop and cleanup trace structures
687 * @q: the request queue associated with the device
688 *
689 **/
690 void blk_trace_shutdown(struct request_queue *q)
691 {
692 if (q->blk_trace) {
693 blk_trace_startstop(q, 0);
694 blk_trace_remove(q);
695 }
696 }
697
698 /*
699 * blktrace probes
700 */
701
702 /**
703 * blk_add_trace_rq - Add a trace for a request oriented action
704 * @q: queue the io is for
705 * @rq: the source request
706 * @nr_bytes: number of completed bytes
707 * @what: the action
708 *
709 * Description:
710 * Records an action against a request. Will log the bio offset + size.
711 *
712 **/
713 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
714 unsigned int nr_bytes, u32 what)
715 {
716 struct blk_trace *bt = q->blk_trace;
717
718 if (likely(!bt))
719 return;
720
721 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
722 what |= BLK_TC_ACT(BLK_TC_PC);
723 __blk_add_trace(bt, 0, nr_bytes, rq->cmd_flags,
724 what, rq->errors, rq->cmd_len, rq->cmd);
725 } else {
726 what |= BLK_TC_ACT(BLK_TC_FS);
727 __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes,
728 rq->cmd_flags, what, rq->errors, 0, NULL);
729 }
730 }
731
732 static void blk_add_trace_rq_abort(void *ignore,
733 struct request_queue *q, struct request *rq)
734 {
735 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT);
736 }
737
738 static void blk_add_trace_rq_insert(void *ignore,
739 struct request_queue *q, struct request *rq)
740 {
741 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT);
742 }
743
744 static void blk_add_trace_rq_issue(void *ignore,
745 struct request_queue *q, struct request *rq)
746 {
747 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE);
748 }
749
750 static void blk_add_trace_rq_requeue(void *ignore,
751 struct request_queue *q,
752 struct request *rq)
753 {
754 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE);
755 }
756
757 static void blk_add_trace_rq_complete(void *ignore,
758 struct request_queue *q,
759 struct request *rq,
760 unsigned int nr_bytes)
761 {
762 blk_add_trace_rq(q, rq, nr_bytes, BLK_TA_COMPLETE);
763 }
764
765 /**
766 * blk_add_trace_bio - Add a trace for a bio oriented action
767 * @q: queue the io is for
768 * @bio: the source bio
769 * @what: the action
770 * @error: error, if any
771 *
772 * Description:
773 * Records an action against a bio. Will log the bio offset + size.
774 *
775 **/
776 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
777 u32 what, int error)
778 {
779 struct blk_trace *bt = q->blk_trace;
780
781 if (likely(!bt))
782 return;
783
784 if (!error && !bio_flagged(bio, BIO_UPTODATE))
785 error = EIO;
786
787 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
788 error, 0, NULL);
789 }
790
791 static void blk_add_trace_bio_bounce(void *ignore,
792 struct request_queue *q, struct bio *bio)
793 {
794 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
795 }
796
797 static void blk_add_trace_bio_complete(void *ignore,
798 struct request_queue *q, struct bio *bio,
799 int error)
800 {
801 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
802 }
803
804 static void blk_add_trace_bio_backmerge(void *ignore,
805 struct request_queue *q,
806 struct request *rq,
807 struct bio *bio)
808 {
809 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
810 }
811
812 static void blk_add_trace_bio_frontmerge(void *ignore,
813 struct request_queue *q,
814 struct request *rq,
815 struct bio *bio)
816 {
817 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
818 }
819
820 static void blk_add_trace_bio_queue(void *ignore,
821 struct request_queue *q, struct bio *bio)
822 {
823 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
824 }
825
826 static void blk_add_trace_getrq(void *ignore,
827 struct request_queue *q,
828 struct bio *bio, int rw)
829 {
830 if (bio)
831 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
832 else {
833 struct blk_trace *bt = q->blk_trace;
834
835 if (bt)
836 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
837 }
838 }
839
840
841 static void blk_add_trace_sleeprq(void *ignore,
842 struct request_queue *q,
843 struct bio *bio, int rw)
844 {
845 if (bio)
846 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
847 else {
848 struct blk_trace *bt = q->blk_trace;
849
850 if (bt)
851 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
852 0, 0, NULL);
853 }
854 }
855
856 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
857 {
858 struct blk_trace *bt = q->blk_trace;
859
860 if (bt)
861 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
862 }
863
864 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
865 unsigned int depth, bool explicit)
866 {
867 struct blk_trace *bt = q->blk_trace;
868
869 if (bt) {
870 __be64 rpdu = cpu_to_be64(depth);
871 u32 what;
872
873 if (explicit)
874 what = BLK_TA_UNPLUG_IO;
875 else
876 what = BLK_TA_UNPLUG_TIMER;
877
878 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
879 }
880 }
881
882 static void blk_add_trace_split(void *ignore,
883 struct request_queue *q, struct bio *bio,
884 unsigned int pdu)
885 {
886 struct blk_trace *bt = q->blk_trace;
887
888 if (bt) {
889 __be64 rpdu = cpu_to_be64(pdu);
890
891 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
892 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
893 sizeof(rpdu), &rpdu);
894 }
895 }
896
897 /**
898 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
899 * @ignore: trace callback data parameter (not used)
900 * @q: queue the io is for
901 * @bio: the source bio
902 * @dev: target device
903 * @from: source sector
904 *
905 * Description:
906 * Device mapper or raid target sometimes need to split a bio because
907 * it spans a stripe (or similar). Add a trace for that action.
908 *
909 **/
910 static void blk_add_trace_bio_remap(void *ignore,
911 struct request_queue *q, struct bio *bio,
912 dev_t dev, sector_t from)
913 {
914 struct blk_trace *bt = q->blk_trace;
915 struct blk_io_trace_remap r;
916
917 if (likely(!bt))
918 return;
919
920 r.device_from = cpu_to_be32(dev);
921 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
922 r.sector_from = cpu_to_be64(from);
923
924 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
925 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
926 sizeof(r), &r);
927 }
928
929 /**
930 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
931 * @ignore: trace callback data parameter (not used)
932 * @q: queue the io is for
933 * @rq: the source request
934 * @dev: target device
935 * @from: source sector
936 *
937 * Description:
938 * Device mapper remaps request to other devices.
939 * Add a trace for that action.
940 *
941 **/
942 static void blk_add_trace_rq_remap(void *ignore,
943 struct request_queue *q,
944 struct request *rq, dev_t dev,
945 sector_t from)
946 {
947 struct blk_trace *bt = q->blk_trace;
948 struct blk_io_trace_remap r;
949
950 if (likely(!bt))
951 return;
952
953 r.device_from = cpu_to_be32(dev);
954 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
955 r.sector_from = cpu_to_be64(from);
956
957 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
958 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
959 sizeof(r), &r);
960 }
961
962 /**
963 * blk_add_driver_data - Add binary message with driver-specific data
964 * @q: queue the io is for
965 * @rq: io request
966 * @data: driver-specific data
967 * @len: length of driver-specific data
968 *
969 * Description:
970 * Some drivers might want to write driver-specific data per request.
971 *
972 **/
973 void blk_add_driver_data(struct request_queue *q,
974 struct request *rq,
975 void *data, size_t len)
976 {
977 struct blk_trace *bt = q->blk_trace;
978
979 if (likely(!bt))
980 return;
981
982 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
983 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
984 BLK_TA_DRV_DATA, rq->errors, len, data);
985 else
986 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
987 BLK_TA_DRV_DATA, rq->errors, len, data);
988 }
989 EXPORT_SYMBOL_GPL(blk_add_driver_data);
990
991 static void blk_register_tracepoints(void)
992 {
993 int ret;
994
995 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1006 WARN_ON(ret);
1007 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1008 WARN_ON(ret);
1009 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1010 WARN_ON(ret);
1011 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1012 WARN_ON(ret);
1013 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1014 WARN_ON(ret);
1015 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1016 WARN_ON(ret);
1017 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1018 WARN_ON(ret);
1019 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1020 WARN_ON(ret);
1021 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1022 WARN_ON(ret);
1023 ret = register_trace_block_split(blk_add_trace_split, NULL);
1024 WARN_ON(ret);
1025 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1026 WARN_ON(ret);
1027 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1028 WARN_ON(ret);
1029 }
1030
1031 static void blk_unregister_tracepoints(void)
1032 {
1033 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1034 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1035 unregister_trace_block_split(blk_add_trace_split, NULL);
1036 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1037 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1038 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1039 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1040 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1041 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1042 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1043 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1044 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1045 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1046 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1047 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1048 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1049 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1050
1051 tracepoint_synchronize_unregister();
1052 }
1053
1054 /*
1055 * struct blk_io_tracer formatting routines
1056 */
1057
1058 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1059 {
1060 int i = 0;
1061 int tc = t->action >> BLK_TC_SHIFT;
1062
1063 if (t->action == BLK_TN_MESSAGE) {
1064 rwbs[i++] = 'N';
1065 goto out;
1066 }
1067
1068 if (tc & BLK_TC_FLUSH)
1069 rwbs[i++] = 'F';
1070
1071 if (tc & BLK_TC_DISCARD)
1072 rwbs[i++] = 'D';
1073 else if (tc & BLK_TC_WRITE)
1074 rwbs[i++] = 'W';
1075 else if (t->bytes)
1076 rwbs[i++] = 'R';
1077 else
1078 rwbs[i++] = 'N';
1079
1080 if (tc & BLK_TC_FUA)
1081 rwbs[i++] = 'F';
1082 if (tc & BLK_TC_AHEAD)
1083 rwbs[i++] = 'A';
1084 if (tc & BLK_TC_SYNC)
1085 rwbs[i++] = 'S';
1086 if (tc & BLK_TC_META)
1087 rwbs[i++] = 'M';
1088 out:
1089 rwbs[i] = '\0';
1090 }
1091
1092 static inline
1093 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1094 {
1095 return (const struct blk_io_trace *)ent;
1096 }
1097
1098 static inline const void *pdu_start(const struct trace_entry *ent)
1099 {
1100 return te_blk_io_trace(ent) + 1;
1101 }
1102
1103 static inline u32 t_action(const struct trace_entry *ent)
1104 {
1105 return te_blk_io_trace(ent)->action;
1106 }
1107
1108 static inline u32 t_bytes(const struct trace_entry *ent)
1109 {
1110 return te_blk_io_trace(ent)->bytes;
1111 }
1112
1113 static inline u32 t_sec(const struct trace_entry *ent)
1114 {
1115 return te_blk_io_trace(ent)->bytes >> 9;
1116 }
1117
1118 static inline unsigned long long t_sector(const struct trace_entry *ent)
1119 {
1120 return te_blk_io_trace(ent)->sector;
1121 }
1122
1123 static inline __u16 t_error(const struct trace_entry *ent)
1124 {
1125 return te_blk_io_trace(ent)->error;
1126 }
1127
1128 static __u64 get_pdu_int(const struct trace_entry *ent)
1129 {
1130 const __u64 *val = pdu_start(ent);
1131 return be64_to_cpu(*val);
1132 }
1133
1134 static void get_pdu_remap(const struct trace_entry *ent,
1135 struct blk_io_trace_remap *r)
1136 {
1137 const struct blk_io_trace_remap *__r = pdu_start(ent);
1138 __u64 sector_from = __r->sector_from;
1139
1140 r->device_from = be32_to_cpu(__r->device_from);
1141 r->device_to = be32_to_cpu(__r->device_to);
1142 r->sector_from = be64_to_cpu(sector_from);
1143 }
1144
1145 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1146
1147 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1148 {
1149 char rwbs[RWBS_LEN];
1150 unsigned long long ts = iter->ts;
1151 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1152 unsigned secs = (unsigned long)ts;
1153 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1154
1155 fill_rwbs(rwbs, t);
1156
1157 return trace_seq_printf(&iter->seq,
1158 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1159 MAJOR(t->device), MINOR(t->device), iter->cpu,
1160 secs, nsec_rem, iter->ent->pid, act, rwbs);
1161 }
1162
1163 static int blk_log_action(struct trace_iterator *iter, const char *act)
1164 {
1165 char rwbs[RWBS_LEN];
1166 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1167
1168 fill_rwbs(rwbs, t);
1169 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1170 MAJOR(t->device), MINOR(t->device), act, rwbs);
1171 }
1172
1173 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1174 {
1175 const unsigned char *pdu_buf;
1176 int pdu_len;
1177 int i, end, ret;
1178
1179 pdu_buf = pdu_start(ent);
1180 pdu_len = te_blk_io_trace(ent)->pdu_len;
1181
1182 if (!pdu_len)
1183 return 1;
1184
1185 /* find the last zero that needs to be printed */
1186 for (end = pdu_len - 1; end >= 0; end--)
1187 if (pdu_buf[end])
1188 break;
1189 end++;
1190
1191 if (!trace_seq_putc(s, '('))
1192 return 0;
1193
1194 for (i = 0; i < pdu_len; i++) {
1195
1196 ret = trace_seq_printf(s, "%s%02x",
1197 i == 0 ? "" : " ", pdu_buf[i]);
1198 if (!ret)
1199 return ret;
1200
1201 /*
1202 * stop when the rest is just zeroes and indicate so
1203 * with a ".." appended
1204 */
1205 if (i == end && end != pdu_len - 1)
1206 return trace_seq_puts(s, " ..) ");
1207 }
1208
1209 return trace_seq_puts(s, ") ");
1210 }
1211
1212 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1213 {
1214 char cmd[TASK_COMM_LEN];
1215
1216 trace_find_cmdline(ent->pid, cmd);
1217
1218 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1219 int ret;
1220
1221 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1222 if (!ret)
1223 return 0;
1224 ret = blk_log_dump_pdu(s, ent);
1225 if (!ret)
1226 return 0;
1227 return trace_seq_printf(s, "[%s]\n", cmd);
1228 } else {
1229 if (t_sec(ent))
1230 return trace_seq_printf(s, "%llu + %u [%s]\n",
1231 t_sector(ent), t_sec(ent), cmd);
1232 return trace_seq_printf(s, "[%s]\n", cmd);
1233 }
1234 }
1235
1236 static int blk_log_with_error(struct trace_seq *s,
1237 const struct trace_entry *ent)
1238 {
1239 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1240 int ret;
1241
1242 ret = blk_log_dump_pdu(s, ent);
1243 if (ret)
1244 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1245 return 0;
1246 } else {
1247 if (t_sec(ent))
1248 return trace_seq_printf(s, "%llu + %u [%d]\n",
1249 t_sector(ent),
1250 t_sec(ent), t_error(ent));
1251 return trace_seq_printf(s, "%llu [%d]\n",
1252 t_sector(ent), t_error(ent));
1253 }
1254 }
1255
1256 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1257 {
1258 struct blk_io_trace_remap r = { .device_from = 0, };
1259
1260 get_pdu_remap(ent, &r);
1261 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1262 t_sector(ent), t_sec(ent),
1263 MAJOR(r.device_from), MINOR(r.device_from),
1264 (unsigned long long)r.sector_from);
1265 }
1266
1267 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1268 {
1269 char cmd[TASK_COMM_LEN];
1270
1271 trace_find_cmdline(ent->pid, cmd);
1272
1273 return trace_seq_printf(s, "[%s]\n", cmd);
1274 }
1275
1276 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1277 {
1278 char cmd[TASK_COMM_LEN];
1279
1280 trace_find_cmdline(ent->pid, cmd);
1281
1282 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1283 }
1284
1285 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1286 {
1287 char cmd[TASK_COMM_LEN];
1288
1289 trace_find_cmdline(ent->pid, cmd);
1290
1291 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1292 get_pdu_int(ent), cmd);
1293 }
1294
1295 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1296 {
1297 int ret;
1298 const struct blk_io_trace *t = te_blk_io_trace(ent);
1299
1300 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1301 if (ret)
1302 return trace_seq_putc(s, '\n');
1303 return ret;
1304 }
1305
1306 /*
1307 * struct tracer operations
1308 */
1309
1310 static void blk_tracer_print_header(struct seq_file *m)
1311 {
1312 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1313 return;
1314 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1315 "# | | | | | |\n");
1316 }
1317
1318 static void blk_tracer_start(struct trace_array *tr)
1319 {
1320 blk_tracer_enabled = true;
1321 }
1322
1323 static int blk_tracer_init(struct trace_array *tr)
1324 {
1325 blk_tr = tr;
1326 blk_tracer_start(tr);
1327 return 0;
1328 }
1329
1330 static void blk_tracer_stop(struct trace_array *tr)
1331 {
1332 blk_tracer_enabled = false;
1333 }
1334
1335 static void blk_tracer_reset(struct trace_array *tr)
1336 {
1337 blk_tracer_stop(tr);
1338 }
1339
1340 static const struct {
1341 const char *act[2];
1342 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1343 } what2act[] = {
1344 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1345 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1346 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1347 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1348 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1349 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1350 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1351 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1352 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1353 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1354 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1355 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1356 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1357 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1358 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1359 };
1360
1361 static enum print_line_t print_one_line(struct trace_iterator *iter,
1362 bool classic)
1363 {
1364 struct trace_seq *s = &iter->seq;
1365 const struct blk_io_trace *t;
1366 u16 what;
1367 int ret;
1368 bool long_act;
1369 blk_log_action_t *log_action;
1370
1371 t = te_blk_io_trace(iter->ent);
1372 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1373 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1374 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1375
1376 if (t->action == BLK_TN_MESSAGE) {
1377 ret = log_action(iter, long_act ? "message" : "m");
1378 if (ret)
1379 ret = blk_log_msg(s, iter->ent);
1380 goto out;
1381 }
1382
1383 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1384 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1385 else {
1386 ret = log_action(iter, what2act[what].act[long_act]);
1387 if (ret)
1388 ret = what2act[what].print(s, iter->ent);
1389 }
1390 out:
1391 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1392 }
1393
1394 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1395 int flags, struct trace_event *event)
1396 {
1397 return print_one_line(iter, false);
1398 }
1399
1400 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1401 {
1402 struct trace_seq *s = &iter->seq;
1403 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1404 const int offset = offsetof(struct blk_io_trace, sector);
1405 struct blk_io_trace old = {
1406 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1407 .time = iter->ts,
1408 };
1409
1410 if (!trace_seq_putmem(s, &old, offset))
1411 return 0;
1412 return trace_seq_putmem(s, &t->sector,
1413 sizeof(old) - offset + t->pdu_len);
1414 }
1415
1416 static enum print_line_t
1417 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1418 struct trace_event *event)
1419 {
1420 return blk_trace_synthesize_old_trace(iter) ?
1421 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1422 }
1423
1424 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1425 {
1426 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1427 return TRACE_TYPE_UNHANDLED;
1428
1429 return print_one_line(iter, true);
1430 }
1431
1432 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1433 {
1434 /* don't output context-info for blk_classic output */
1435 if (bit == TRACE_BLK_OPT_CLASSIC) {
1436 if (set)
1437 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1438 else
1439 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1440 }
1441 return 0;
1442 }
1443
1444 static struct tracer blk_tracer __read_mostly = {
1445 .name = "blk",
1446 .init = blk_tracer_init,
1447 .reset = blk_tracer_reset,
1448 .start = blk_tracer_start,
1449 .stop = blk_tracer_stop,
1450 .print_header = blk_tracer_print_header,
1451 .print_line = blk_tracer_print_line,
1452 .flags = &blk_tracer_flags,
1453 .set_flag = blk_tracer_set_flag,
1454 };
1455
1456 static struct trace_event_functions trace_blk_event_funcs = {
1457 .trace = blk_trace_event_print,
1458 .binary = blk_trace_event_print_binary,
1459 };
1460
1461 static struct trace_event trace_blk_event = {
1462 .type = TRACE_BLK,
1463 .funcs = &trace_blk_event_funcs,
1464 };
1465
1466 static int __init init_blk_tracer(void)
1467 {
1468 if (!register_ftrace_event(&trace_blk_event)) {
1469 pr_warning("Warning: could not register block events\n");
1470 return 1;
1471 }
1472
1473 if (register_tracer(&blk_tracer) != 0) {
1474 pr_warning("Warning: could not register the block tracer\n");
1475 unregister_ftrace_event(&trace_blk_event);
1476 return 1;
1477 }
1478
1479 return 0;
1480 }
1481
1482 device_initcall(init_blk_tracer);
1483
1484 static int blk_trace_remove_queue(struct request_queue *q)
1485 {
1486 struct blk_trace *bt;
1487
1488 bt = xchg(&q->blk_trace, NULL);
1489 if (bt == NULL)
1490 return -EINVAL;
1491
1492 if (atomic_dec_and_test(&blk_probes_ref))
1493 blk_unregister_tracepoints();
1494
1495 spin_lock_irq(&running_trace_lock);
1496 list_del(&bt->running_list);
1497 spin_unlock_irq(&running_trace_lock);
1498 blk_trace_free(bt);
1499 return 0;
1500 }
1501
1502 /*
1503 * Setup everything required to start tracing
1504 */
1505 static int blk_trace_setup_queue(struct request_queue *q,
1506 struct block_device *bdev)
1507 {
1508 struct blk_trace *old_bt, *bt = NULL;
1509 int ret = -ENOMEM;
1510
1511 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1512 if (!bt)
1513 return -ENOMEM;
1514
1515 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1516 if (!bt->msg_data)
1517 goto free_bt;
1518
1519 bt->dev = bdev->bd_dev;
1520 bt->act_mask = (u16)-1;
1521
1522 blk_trace_setup_lba(bt, bdev);
1523
1524 old_bt = xchg(&q->blk_trace, bt);
1525 if (old_bt != NULL) {
1526 (void)xchg(&q->blk_trace, old_bt);
1527 ret = -EBUSY;
1528 goto free_bt;
1529 }
1530
1531 if (atomic_inc_return(&blk_probes_ref) == 1)
1532 blk_register_tracepoints();
1533 return 0;
1534
1535 free_bt:
1536 blk_trace_free(bt);
1537 return ret;
1538 }
1539
1540 /*
1541 * sysfs interface to enable and configure tracing
1542 */
1543
1544 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1545 struct device_attribute *attr,
1546 char *buf);
1547 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1548 struct device_attribute *attr,
1549 const char *buf, size_t count);
1550 #define BLK_TRACE_DEVICE_ATTR(_name) \
1551 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1552 sysfs_blk_trace_attr_show, \
1553 sysfs_blk_trace_attr_store)
1554
1555 static BLK_TRACE_DEVICE_ATTR(enable);
1556 static BLK_TRACE_DEVICE_ATTR(act_mask);
1557 static BLK_TRACE_DEVICE_ATTR(pid);
1558 static BLK_TRACE_DEVICE_ATTR(start_lba);
1559 static BLK_TRACE_DEVICE_ATTR(end_lba);
1560
1561 static struct attribute *blk_trace_attrs[] = {
1562 &dev_attr_enable.attr,
1563 &dev_attr_act_mask.attr,
1564 &dev_attr_pid.attr,
1565 &dev_attr_start_lba.attr,
1566 &dev_attr_end_lba.attr,
1567 NULL
1568 };
1569
1570 struct attribute_group blk_trace_attr_group = {
1571 .name = "trace",
1572 .attrs = blk_trace_attrs,
1573 };
1574
1575 static const struct {
1576 int mask;
1577 const char *str;
1578 } mask_maps[] = {
1579 { BLK_TC_READ, "read" },
1580 { BLK_TC_WRITE, "write" },
1581 { BLK_TC_FLUSH, "flush" },
1582 { BLK_TC_SYNC, "sync" },
1583 { BLK_TC_QUEUE, "queue" },
1584 { BLK_TC_REQUEUE, "requeue" },
1585 { BLK_TC_ISSUE, "issue" },
1586 { BLK_TC_COMPLETE, "complete" },
1587 { BLK_TC_FS, "fs" },
1588 { BLK_TC_PC, "pc" },
1589 { BLK_TC_AHEAD, "ahead" },
1590 { BLK_TC_META, "meta" },
1591 { BLK_TC_DISCARD, "discard" },
1592 { BLK_TC_DRV_DATA, "drv_data" },
1593 { BLK_TC_FUA, "fua" },
1594 };
1595
1596 static int blk_trace_str2mask(const char *str)
1597 {
1598 int i;
1599 int mask = 0;
1600 char *buf, *s, *token;
1601
1602 buf = kstrdup(str, GFP_KERNEL);
1603 if (buf == NULL)
1604 return -ENOMEM;
1605 s = strstrip(buf);
1606
1607 while (1) {
1608 token = strsep(&s, ",");
1609 if (token == NULL)
1610 break;
1611
1612 if (*token == '\0')
1613 continue;
1614
1615 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1616 if (strcasecmp(token, mask_maps[i].str) == 0) {
1617 mask |= mask_maps[i].mask;
1618 break;
1619 }
1620 }
1621 if (i == ARRAY_SIZE(mask_maps)) {
1622 mask = -EINVAL;
1623 break;
1624 }
1625 }
1626 kfree(buf);
1627
1628 return mask;
1629 }
1630
1631 static ssize_t blk_trace_mask2str(char *buf, int mask)
1632 {
1633 int i;
1634 char *p = buf;
1635
1636 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1637 if (mask & mask_maps[i].mask) {
1638 p += sprintf(p, "%s%s",
1639 (p == buf) ? "" : ",", mask_maps[i].str);
1640 }
1641 }
1642 *p++ = '\n';
1643
1644 return p - buf;
1645 }
1646
1647 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1648 {
1649 if (bdev->bd_disk == NULL)
1650 return NULL;
1651
1652 return bdev_get_queue(bdev);
1653 }
1654
1655 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1656 struct device_attribute *attr,
1657 char *buf)
1658 {
1659 struct hd_struct *p = dev_to_part(dev);
1660 struct request_queue *q;
1661 struct block_device *bdev;
1662 ssize_t ret = -ENXIO;
1663
1664 bdev = bdget(part_devt(p));
1665 if (bdev == NULL)
1666 goto out;
1667
1668 q = blk_trace_get_queue(bdev);
1669 if (q == NULL)
1670 goto out_bdput;
1671
1672 mutex_lock(&bdev->bd_mutex);
1673
1674 if (attr == &dev_attr_enable) {
1675 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1676 goto out_unlock_bdev;
1677 }
1678
1679 if (q->blk_trace == NULL)
1680 ret = sprintf(buf, "disabled\n");
1681 else if (attr == &dev_attr_act_mask)
1682 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1683 else if (attr == &dev_attr_pid)
1684 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1685 else if (attr == &dev_attr_start_lba)
1686 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1687 else if (attr == &dev_attr_end_lba)
1688 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1689
1690 out_unlock_bdev:
1691 mutex_unlock(&bdev->bd_mutex);
1692 out_bdput:
1693 bdput(bdev);
1694 out:
1695 return ret;
1696 }
1697
1698 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1699 struct device_attribute *attr,
1700 const char *buf, size_t count)
1701 {
1702 struct block_device *bdev;
1703 struct request_queue *q;
1704 struct hd_struct *p;
1705 u64 value;
1706 ssize_t ret = -EINVAL;
1707
1708 if (count == 0)
1709 goto out;
1710
1711 if (attr == &dev_attr_act_mask) {
1712 if (sscanf(buf, "%llx", &value) != 1) {
1713 /* Assume it is a list of trace category names */
1714 ret = blk_trace_str2mask(buf);
1715 if (ret < 0)
1716 goto out;
1717 value = ret;
1718 }
1719 } else if (sscanf(buf, "%llu", &value) != 1)
1720 goto out;
1721
1722 ret = -ENXIO;
1723
1724 p = dev_to_part(dev);
1725 bdev = bdget(part_devt(p));
1726 if (bdev == NULL)
1727 goto out;
1728
1729 q = blk_trace_get_queue(bdev);
1730 if (q == NULL)
1731 goto out_bdput;
1732
1733 mutex_lock(&bdev->bd_mutex);
1734
1735 if (attr == &dev_attr_enable) {
1736 if (value)
1737 ret = blk_trace_setup_queue(q, bdev);
1738 else
1739 ret = blk_trace_remove_queue(q);
1740 goto out_unlock_bdev;
1741 }
1742
1743 ret = 0;
1744 if (q->blk_trace == NULL)
1745 ret = blk_trace_setup_queue(q, bdev);
1746
1747 if (ret == 0) {
1748 if (attr == &dev_attr_act_mask)
1749 q->blk_trace->act_mask = value;
1750 else if (attr == &dev_attr_pid)
1751 q->blk_trace->pid = value;
1752 else if (attr == &dev_attr_start_lba)
1753 q->blk_trace->start_lba = value;
1754 else if (attr == &dev_attr_end_lba)
1755 q->blk_trace->end_lba = value;
1756 }
1757
1758 out_unlock_bdev:
1759 mutex_unlock(&bdev->bd_mutex);
1760 out_bdput:
1761 bdput(bdev);
1762 out:
1763 return ret ? ret : count;
1764 }
1765
1766 int blk_trace_init_sysfs(struct device *dev)
1767 {
1768 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1769 }
1770
1771 void blk_trace_remove_sysfs(struct device *dev)
1772 {
1773 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1774 }
1775
1776 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1777
1778 #ifdef CONFIG_EVENT_TRACING
1779
1780 void blk_dump_cmd(char *buf, struct request *rq)
1781 {
1782 int i, end;
1783 int len = rq->cmd_len;
1784 unsigned char *cmd = rq->cmd;
1785
1786 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1787 buf[0] = '\0';
1788 return;
1789 }
1790
1791 for (end = len - 1; end >= 0; end--)
1792 if (cmd[end])
1793 break;
1794 end++;
1795
1796 for (i = 0; i < len; i++) {
1797 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1798 if (i == end && end != len - 1) {
1799 sprintf(buf, " ..");
1800 break;
1801 }
1802 }
1803 }
1804
1805 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1806 {
1807 int i = 0;
1808
1809 if (rw & REQ_FLUSH)
1810 rwbs[i++] = 'F';
1811
1812 if (rw & WRITE)
1813 rwbs[i++] = 'W';
1814 else if (rw & REQ_DISCARD)
1815 rwbs[i++] = 'D';
1816 else if (bytes)
1817 rwbs[i++] = 'R';
1818 else
1819 rwbs[i++] = 'N';
1820
1821 if (rw & REQ_FUA)
1822 rwbs[i++] = 'F';
1823 if (rw & REQ_RAHEAD)
1824 rwbs[i++] = 'A';
1825 if (rw & REQ_SYNC)
1826 rwbs[i++] = 'S';
1827 if (rw & REQ_META)
1828 rwbs[i++] = 'M';
1829 if (rw & REQ_SECURE)
1830 rwbs[i++] = 'E';
1831
1832 rwbs[i] = '\0';
1833 }
1834 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1835
1836 #endif /* CONFIG_EVENT_TRACING */
1837
Linux with added FPC-III support