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Merge tag 'chrome-platform-for-linus-4.13' of git://git.kernel.org/pub/scm/linux...
[linux/fpc-iii.git] / kernel / trace / blktrace.c
blobbc364f86100aa89f5d7b463d8c5465d1505766ce
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 "../../block/blk.h"
32
33 #include <trace/events/block.h>
34
35 #include "trace_output.h"
36
37 #ifdef CONFIG_BLK_DEV_IO_TRACE
38
39 static unsigned int blktrace_seq __read_mostly = 1;
40
41 static struct trace_array *blk_tr;
42 static bool blk_tracer_enabled __read_mostly;
43
44 static LIST_HEAD(running_trace_list);
45 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
46
47 /* Select an alternative, minimalistic output than the original one */
48 #define TRACE_BLK_OPT_CLASSIC 0x1
49
50 static struct tracer_opt blk_tracer_opts[] = {
51 /* Default disable the minimalistic output */
52 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
53 { }
54 };
55
56 static struct tracer_flags blk_tracer_flags = {
57 .val = 0,
58 .opts = blk_tracer_opts,
59 };
60
61 /* Global reference count of probes */
62 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
63
64 static void blk_register_tracepoints(void);
65 static void blk_unregister_tracepoints(void);
66
67 /*
68 * Send out a notify message.
69 */
70 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
71 const void *data, size_t len)
72 {
73 struct blk_io_trace *t;
74 struct ring_buffer_event *event = NULL;
75 struct ring_buffer *buffer = NULL;
76 int pc = 0;
77 int cpu = smp_processor_id();
78 bool blk_tracer = blk_tracer_enabled;
79
80 if (blk_tracer) {
81 buffer = blk_tr->trace_buffer.buffer;
82 pc = preempt_count();
83 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
84 sizeof(*t) + len,
85 0, pc);
86 if (!event)
87 return;
88 t = ring_buffer_event_data(event);
89 goto record_it;
90 }
91
92 if (!bt->rchan)
93 return;
94
95 t = relay_reserve(bt->rchan, sizeof(*t) + len);
96 if (t) {
97 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
98 t->time = ktime_to_ns(ktime_get());
99 record_it:
100 t->device = bt->dev;
101 t->action = action;
102 t->pid = pid;
103 t->cpu = cpu;
104 t->pdu_len = len;
105 memcpy((void *) t + sizeof(*t), data, len);
106
107 if (blk_tracer)
108 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
109 }
110 }
111
112 /*
113 * Send out a notify for this process, if we haven't done so since a trace
114 * started
115 */
116 static void trace_note_tsk(struct task_struct *tsk)
117 {
118 unsigned long flags;
119 struct blk_trace *bt;
120
121 tsk->btrace_seq = blktrace_seq;
122 spin_lock_irqsave(&running_trace_lock, flags);
123 list_for_each_entry(bt, &running_trace_list, running_list) {
124 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
125 sizeof(tsk->comm));
126 }
127 spin_unlock_irqrestore(&running_trace_lock, flags);
128 }
129
130 static void trace_note_time(struct blk_trace *bt)
131 {
132 struct timespec64 now;
133 unsigned long flags;
134 u32 words[2];
135
136 /* need to check user space to see if this breaks in y2038 or y2106 */
137 ktime_get_real_ts64(&now);
138 words[0] = (u32)now.tv_sec;
139 words[1] = now.tv_nsec;
140
141 local_irq_save(flags);
142 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
143 local_irq_restore(flags);
144 }
145
146 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
147 {
148 int n;
149 va_list args;
150 unsigned long flags;
151 char *buf;
152
153 if (unlikely(bt->trace_state != Blktrace_running &&
154 !blk_tracer_enabled))
155 return;
156
157 /*
158 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
159 * message to the trace.
160 */
161 if (!(bt->act_mask & BLK_TC_NOTIFY))
162 return;
163
164 local_irq_save(flags);
165 buf = this_cpu_ptr(bt->msg_data);
166 va_start(args, fmt);
167 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
168 va_end(args);
169
170 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
171 local_irq_restore(flags);
172 }
173 EXPORT_SYMBOL_GPL(__trace_note_message);
174
175 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
176 pid_t pid)
177 {
178 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
179 return 1;
180 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
181 return 1;
182 if (bt->pid && pid != bt->pid)
183 return 1;
184
185 return 0;
186 }
187
188 /*
189 * Data direction bit lookup
190 */
191 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
192 BLK_TC_ACT(BLK_TC_WRITE) };
193
194 #define BLK_TC_RAHEAD BLK_TC_AHEAD
195 #define BLK_TC_PREFLUSH BLK_TC_FLUSH
196
197 /* The ilog2() calls fall out because they're constant */
198 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
199 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
200
201 /*
202 * The worker for the various blk_add_trace*() types. Fills out a
203 * blk_io_trace structure and places it in a per-cpu subbuffer.
204 */
205 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
206 int op, int op_flags, u32 what, int error, int pdu_len,
207 void *pdu_data)
208 {
209 struct task_struct *tsk = current;
210 struct ring_buffer_event *event = NULL;
211 struct ring_buffer *buffer = NULL;
212 struct blk_io_trace *t;
213 unsigned long flags = 0;
214 unsigned long *sequence;
215 pid_t pid;
216 int cpu, pc = 0;
217 bool blk_tracer = blk_tracer_enabled;
218
219 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
220 return;
221
222 what |= ddir_act[op_is_write(op) ? WRITE : READ];
223 what |= MASK_TC_BIT(op_flags, SYNC);
224 what |= MASK_TC_BIT(op_flags, RAHEAD);
225 what |= MASK_TC_BIT(op_flags, META);
226 what |= MASK_TC_BIT(op_flags, PREFLUSH);
227 what |= MASK_TC_BIT(op_flags, FUA);
228 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
229 what |= BLK_TC_ACT(BLK_TC_DISCARD);
230 if (op == REQ_OP_FLUSH)
231 what |= BLK_TC_ACT(BLK_TC_FLUSH);
232
233 pid = tsk->pid;
234 if (act_log_check(bt, what, sector, pid))
235 return;
236 cpu = raw_smp_processor_id();
237
238 if (blk_tracer) {
239 tracing_record_cmdline(current);
240
241 buffer = blk_tr->trace_buffer.buffer;
242 pc = preempt_count();
243 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
244 sizeof(*t) + pdu_len,
245 0, pc);
246 if (!event)
247 return;
248 t = ring_buffer_event_data(event);
249 goto record_it;
250 }
251
252 if (unlikely(tsk->btrace_seq != blktrace_seq))
253 trace_note_tsk(tsk);
254
255 /*
256 * A word about the locking here - we disable interrupts to reserve
257 * some space in the relay per-cpu buffer, to prevent an irq
258 * from coming in and stepping on our toes.
259 */
260 local_irq_save(flags);
261 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
262 if (t) {
263 sequence = per_cpu_ptr(bt->sequence, cpu);
264
265 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
266 t->sequence = ++(*sequence);
267 t->time = ktime_to_ns(ktime_get());
268 record_it:
269 /*
270 * These two are not needed in ftrace as they are in the
271 * generic trace_entry, filled by tracing_generic_entry_update,
272 * but for the trace_event->bin() synthesizer benefit we do it
273 * here too.
274 */
275 t->cpu = cpu;
276 t->pid = pid;
277
278 t->sector = sector;
279 t->bytes = bytes;
280 t->action = what;
281 t->device = bt->dev;
282 t->error = error;
283 t->pdu_len = pdu_len;
284
285 if (pdu_len)
286 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
287
288 if (blk_tracer) {
289 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
290 return;
291 }
292 }
293
294 local_irq_restore(flags);
295 }
296
297 static void blk_trace_free(struct blk_trace *bt)
298 {
299 debugfs_remove(bt->msg_file);
300 debugfs_remove(bt->dropped_file);
301 relay_close(bt->rchan);
302 debugfs_remove(bt->dir);
303 free_percpu(bt->sequence);
304 free_percpu(bt->msg_data);
305 kfree(bt);
306 }
307
308 static void blk_trace_cleanup(struct blk_trace *bt)
309 {
310 blk_trace_free(bt);
311 if (atomic_dec_and_test(&blk_probes_ref))
312 blk_unregister_tracepoints();
313 }
314
315 int blk_trace_remove(struct request_queue *q)
316 {
317 struct blk_trace *bt;
318
319 bt = xchg(&q->blk_trace, NULL);
320 if (!bt)
321 return -EINVAL;
322
323 if (bt->trace_state != Blktrace_running)
324 blk_trace_cleanup(bt);
325
326 return 0;
327 }
328 EXPORT_SYMBOL_GPL(blk_trace_remove);
329
330 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
331 size_t count, loff_t *ppos)
332 {
333 struct blk_trace *bt = filp->private_data;
334 char buf[16];
335
336 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
337
338 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
339 }
340
341 static const struct file_operations blk_dropped_fops = {
342 .owner = THIS_MODULE,
343 .open = simple_open,
344 .read = blk_dropped_read,
345 .llseek = default_llseek,
346 };
347
348 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
349 size_t count, loff_t *ppos)
350 {
351 char *msg;
352 struct blk_trace *bt;
353
354 if (count >= BLK_TN_MAX_MSG)
355 return -EINVAL;
356
357 msg = memdup_user_nul(buffer, count);
358 if (IS_ERR(msg))
359 return PTR_ERR(msg);
360
361 bt = filp->private_data;
362 __trace_note_message(bt, "%s", msg);
363 kfree(msg);
364
365 return count;
366 }
367
368 static const struct file_operations blk_msg_fops = {
369 .owner = THIS_MODULE,
370 .open = simple_open,
371 .write = blk_msg_write,
372 .llseek = noop_llseek,
373 };
374
375 /*
376 * Keep track of how many times we encountered a full subbuffer, to aid
377 * the user space app in telling how many lost events there were.
378 */
379 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
380 void *prev_subbuf, size_t prev_padding)
381 {
382 struct blk_trace *bt;
383
384 if (!relay_buf_full(buf))
385 return 1;
386
387 bt = buf->chan->private_data;
388 atomic_inc(&bt->dropped);
389 return 0;
390 }
391
392 static int blk_remove_buf_file_callback(struct dentry *dentry)
393 {
394 debugfs_remove(dentry);
395
396 return 0;
397 }
398
399 static struct dentry *blk_create_buf_file_callback(const char *filename,
400 struct dentry *parent,
401 umode_t mode,
402 struct rchan_buf *buf,
403 int *is_global)
404 {
405 return debugfs_create_file(filename, mode, parent, buf,
406 &relay_file_operations);
407 }
408
409 static struct rchan_callbacks blk_relay_callbacks = {
410 .subbuf_start = blk_subbuf_start_callback,
411 .create_buf_file = blk_create_buf_file_callback,
412 .remove_buf_file = blk_remove_buf_file_callback,
413 };
414
415 static void blk_trace_setup_lba(struct blk_trace *bt,
416 struct block_device *bdev)
417 {
418 struct hd_struct *part = NULL;
419
420 if (bdev)
421 part = bdev->bd_part;
422
423 if (part) {
424 bt->start_lba = part->start_sect;
425 bt->end_lba = part->start_sect + part->nr_sects;
426 } else {
427 bt->start_lba = 0;
428 bt->end_lba = -1ULL;
429 }
430 }
431
432 /*
433 * Setup everything required to start tracing
434 */
435 static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
436 struct block_device *bdev,
437 struct blk_user_trace_setup *buts)
438 {
439 struct blk_trace *bt = NULL;
440 struct dentry *dir = NULL;
441 int ret;
442
443 if (!buts->buf_size || !buts->buf_nr)
444 return -EINVAL;
445
446 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
447 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
448
449 /*
450 * some device names have larger paths - convert the slashes
451 * to underscores for this to work as expected
452 */
453 strreplace(buts->name, '/', '_');
454
455 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
456 if (!bt)
457 return -ENOMEM;
458
459 ret = -ENOMEM;
460 bt->sequence = alloc_percpu(unsigned long);
461 if (!bt->sequence)
462 goto err;
463
464 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
465 if (!bt->msg_data)
466 goto err;
467
468 ret = -ENOENT;
469
470 if (!blk_debugfs_root)
471 goto err;
472
473 dir = debugfs_lookup(buts->name, blk_debugfs_root);
474 if (!dir)
475 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
476 if (!dir)
477 goto err;
478
479 bt->dev = dev;
480 atomic_set(&bt->dropped, 0);
481 INIT_LIST_HEAD(&bt->running_list);
482
483 ret = -EIO;
484 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
485 &blk_dropped_fops);
486 if (!bt->dropped_file)
487 goto err;
488
489 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
490 if (!bt->msg_file)
491 goto err;
492
493 bt->rchan = relay_open("trace", dir, buts->buf_size,
494 buts->buf_nr, &blk_relay_callbacks, bt);
495 if (!bt->rchan)
496 goto err;
497
498 bt->act_mask = buts->act_mask;
499 if (!bt->act_mask)
500 bt->act_mask = (u16) -1;
501
502 blk_trace_setup_lba(bt, bdev);
503
504 /* overwrite with user settings */
505 if (buts->start_lba)
506 bt->start_lba = buts->start_lba;
507 if (buts->end_lba)
508 bt->end_lba = buts->end_lba;
509
510 bt->pid = buts->pid;
511 bt->trace_state = Blktrace_setup;
512
513 ret = -EBUSY;
514 if (cmpxchg(&q->blk_trace, NULL, bt))
515 goto err;
516
517 if (atomic_inc_return(&blk_probes_ref) == 1)
518 blk_register_tracepoints();
519
520 ret = 0;
521 err:
522 if (dir && !bt->dir)
523 dput(dir);
524 if (ret)
525 blk_trace_free(bt);
526 return ret;
527 }
528
529 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
530 struct block_device *bdev,
531 char __user *arg)
532 {
533 struct blk_user_trace_setup buts;
534 int ret;
535
536 ret = copy_from_user(&buts, arg, sizeof(buts));
537 if (ret)
538 return -EFAULT;
539
540 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
541 if (ret)
542 return ret;
543
544 if (copy_to_user(arg, &buts, sizeof(buts))) {
545 blk_trace_remove(q);
546 return -EFAULT;
547 }
548 return 0;
549 }
550 EXPORT_SYMBOL_GPL(blk_trace_setup);
551
552 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
553 static int compat_blk_trace_setup(struct request_queue *q, char *name,
554 dev_t dev, struct block_device *bdev,
555 char __user *arg)
556 {
557 struct blk_user_trace_setup buts;
558 struct compat_blk_user_trace_setup cbuts;
559 int ret;
560
561 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
562 return -EFAULT;
563
564 buts = (struct blk_user_trace_setup) {
565 .act_mask = cbuts.act_mask,
566 .buf_size = cbuts.buf_size,
567 .buf_nr = cbuts.buf_nr,
568 .start_lba = cbuts.start_lba,
569 .end_lba = cbuts.end_lba,
570 .pid = cbuts.pid,
571 };
572
573 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
574 if (ret)
575 return ret;
576
577 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
578 blk_trace_remove(q);
579 return -EFAULT;
580 }
581
582 return 0;
583 }
584 #endif
585
586 int blk_trace_startstop(struct request_queue *q, int start)
587 {
588 int ret;
589 struct blk_trace *bt = q->blk_trace;
590
591 if (bt == NULL)
592 return -EINVAL;
593
594 /*
595 * For starting a trace, we can transition from a setup or stopped
596 * trace. For stopping a trace, the state must be running
597 */
598 ret = -EINVAL;
599 if (start) {
600 if (bt->trace_state == Blktrace_setup ||
601 bt->trace_state == Blktrace_stopped) {
602 blktrace_seq++;
603 smp_mb();
604 bt->trace_state = Blktrace_running;
605 spin_lock_irq(&running_trace_lock);
606 list_add(&bt->running_list, &running_trace_list);
607 spin_unlock_irq(&running_trace_lock);
608
609 trace_note_time(bt);
610 ret = 0;
611 }
612 } else {
613 if (bt->trace_state == Blktrace_running) {
614 bt->trace_state = Blktrace_stopped;
615 spin_lock_irq(&running_trace_lock);
616 list_del_init(&bt->running_list);
617 spin_unlock_irq(&running_trace_lock);
618 relay_flush(bt->rchan);
619 ret = 0;
620 }
621 }
622
623 return ret;
624 }
625 EXPORT_SYMBOL_GPL(blk_trace_startstop);
626
627 /**
628 * blk_trace_ioctl: - handle the ioctls associated with tracing
629 * @bdev: the block device
630 * @cmd: the ioctl cmd
631 * @arg: the argument data, if any
632 *
633 **/
634 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
635 {
636 struct request_queue *q;
637 int ret, start = 0;
638 char b[BDEVNAME_SIZE];
639
640 q = bdev_get_queue(bdev);
641 if (!q)
642 return -ENXIO;
643
644 mutex_lock(&bdev->bd_mutex);
645
646 switch (cmd) {
647 case BLKTRACESETUP:
648 bdevname(bdev, b);
649 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
650 break;
651 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
652 case BLKTRACESETUP32:
653 bdevname(bdev, b);
654 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
655 break;
656 #endif
657 case BLKTRACESTART:
658 start = 1;
659 case BLKTRACESTOP:
660 ret = blk_trace_startstop(q, start);
661 break;
662 case BLKTRACETEARDOWN:
663 ret = blk_trace_remove(q);
664 break;
665 default:
666 ret = -ENOTTY;
667 break;
668 }
669
670 mutex_unlock(&bdev->bd_mutex);
671 return ret;
672 }
673
674 /**
675 * blk_trace_shutdown: - stop and cleanup trace structures
676 * @q: the request queue associated with the device
677 *
678 **/
679 void blk_trace_shutdown(struct request_queue *q)
680 {
681 if (q->blk_trace) {
682 blk_trace_startstop(q, 0);
683 blk_trace_remove(q);
684 }
685 }
686
687 /*
688 * blktrace probes
689 */
690
691 /**
692 * blk_add_trace_rq - Add a trace for a request oriented action
693 * @rq: the source request
694 * @error: return status to log
695 * @nr_bytes: number of completed bytes
696 * @what: the action
697 *
698 * Description:
699 * Records an action against a request. Will log the bio offset + size.
700 *
701 **/
702 static void blk_add_trace_rq(struct request *rq, int error,
703 unsigned int nr_bytes, u32 what)
704 {
705 struct blk_trace *bt = rq->q->blk_trace;
706
707 if (likely(!bt))
708 return;
709
710 if (blk_rq_is_passthrough(rq))
711 what |= BLK_TC_ACT(BLK_TC_PC);
712 else
713 what |= BLK_TC_ACT(BLK_TC_FS);
714
715 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
716 rq->cmd_flags, what, error, 0, NULL);
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(rq, 0, blk_rq_bytes(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(rq, 0, blk_rq_bytes(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(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE);
736 }
737
738 static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
739 int error, unsigned int nr_bytes)
740 {
741 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE);
742 }
743
744 /**
745 * blk_add_trace_bio - Add a trace for a bio oriented action
746 * @q: queue the io is for
747 * @bio: the source bio
748 * @what: the action
749 * @error: error, if any
750 *
751 * Description:
752 * Records an action against a bio. Will log the bio offset + size.
753 *
754 **/
755 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
756 u32 what, int error)
757 {
758 struct blk_trace *bt = q->blk_trace;
759
760 if (likely(!bt))
761 return;
762
763 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
764 bio_op(bio), bio->bi_opf, what, error, 0, NULL);
765 }
766
767 static void blk_add_trace_bio_bounce(void *ignore,
768 struct request_queue *q, struct bio *bio)
769 {
770 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
771 }
772
773 static void blk_add_trace_bio_complete(void *ignore,
774 struct request_queue *q, struct bio *bio,
775 int error)
776 {
777 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
778 }
779
780 static void blk_add_trace_bio_backmerge(void *ignore,
781 struct request_queue *q,
782 struct request *rq,
783 struct bio *bio)
784 {
785 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
786 }
787
788 static void blk_add_trace_bio_frontmerge(void *ignore,
789 struct request_queue *q,
790 struct request *rq,
791 struct bio *bio)
792 {
793 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
794 }
795
796 static void blk_add_trace_bio_queue(void *ignore,
797 struct request_queue *q, struct bio *bio)
798 {
799 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
800 }
801
802 static void blk_add_trace_getrq(void *ignore,
803 struct request_queue *q,
804 struct bio *bio, int rw)
805 {
806 if (bio)
807 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
808 else {
809 struct blk_trace *bt = q->blk_trace;
810
811 if (bt)
812 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
813 NULL);
814 }
815 }
816
817
818 static void blk_add_trace_sleeprq(void *ignore,
819 struct request_queue *q,
820 struct bio *bio, int rw)
821 {
822 if (bio)
823 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
824 else {
825 struct blk_trace *bt = q->blk_trace;
826
827 if (bt)
828 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
829 0, 0, NULL);
830 }
831 }
832
833 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
834 {
835 struct blk_trace *bt = q->blk_trace;
836
837 if (bt)
838 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
839 }
840
841 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
842 unsigned int depth, bool explicit)
843 {
844 struct blk_trace *bt = q->blk_trace;
845
846 if (bt) {
847 __be64 rpdu = cpu_to_be64(depth);
848 u32 what;
849
850 if (explicit)
851 what = BLK_TA_UNPLUG_IO;
852 else
853 what = BLK_TA_UNPLUG_TIMER;
854
855 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
856 }
857 }
858
859 static void blk_add_trace_split(void *ignore,
860 struct request_queue *q, struct bio *bio,
861 unsigned int pdu)
862 {
863 struct blk_trace *bt = q->blk_trace;
864
865 if (bt) {
866 __be64 rpdu = cpu_to_be64(pdu);
867
868 __blk_add_trace(bt, bio->bi_iter.bi_sector,
869 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
870 BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu),
871 &rpdu);
872 }
873 }
874
875 /**
876 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
877 * @ignore: trace callback data parameter (not used)
878 * @q: queue the io is for
879 * @bio: the source bio
880 * @dev: target device
881 * @from: source sector
882 *
883 * Description:
884 * Device mapper or raid target sometimes need to split a bio because
885 * it spans a stripe (or similar). Add a trace for that action.
886 *
887 **/
888 static void blk_add_trace_bio_remap(void *ignore,
889 struct request_queue *q, struct bio *bio,
890 dev_t dev, sector_t from)
891 {
892 struct blk_trace *bt = q->blk_trace;
893 struct blk_io_trace_remap r;
894
895 if (likely(!bt))
896 return;
897
898 r.device_from = cpu_to_be32(dev);
899 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
900 r.sector_from = cpu_to_be64(from);
901
902 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
903 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status,
904 sizeof(r), &r);
905 }
906
907 /**
908 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
909 * @ignore: trace callback data parameter (not used)
910 * @q: queue the io is for
911 * @rq: the source request
912 * @dev: target device
913 * @from: source sector
914 *
915 * Description:
916 * Device mapper remaps request to other devices.
917 * Add a trace for that action.
918 *
919 **/
920 static void blk_add_trace_rq_remap(void *ignore,
921 struct request_queue *q,
922 struct request *rq, dev_t dev,
923 sector_t from)
924 {
925 struct blk_trace *bt = q->blk_trace;
926 struct blk_io_trace_remap r;
927
928 if (likely(!bt))
929 return;
930
931 r.device_from = cpu_to_be32(dev);
932 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
933 r.sector_from = cpu_to_be64(from);
934
935 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
936 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
937 sizeof(r), &r);
938 }
939
940 /**
941 * blk_add_driver_data - Add binary message with driver-specific data
942 * @q: queue the io is for
943 * @rq: io request
944 * @data: driver-specific data
945 * @len: length of driver-specific data
946 *
947 * Description:
948 * Some drivers might want to write driver-specific data per request.
949 *
950 **/
951 void blk_add_driver_data(struct request_queue *q,
952 struct request *rq,
953 void *data, size_t len)
954 {
955 struct blk_trace *bt = q->blk_trace;
956
957 if (likely(!bt))
958 return;
959
960 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
961 BLK_TA_DRV_DATA, 0, len, data);
962 }
963 EXPORT_SYMBOL_GPL(blk_add_driver_data);
964
965 static void blk_register_tracepoints(void)
966 {
967 int ret;
968
969 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
970 WARN_ON(ret);
971 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
972 WARN_ON(ret);
973 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
974 WARN_ON(ret);
975 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
976 WARN_ON(ret);
977 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
978 WARN_ON(ret);
979 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
980 WARN_ON(ret);
981 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
982 WARN_ON(ret);
983 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
984 WARN_ON(ret);
985 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
986 WARN_ON(ret);
987 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
988 WARN_ON(ret);
989 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
990 WARN_ON(ret);
991 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
992 WARN_ON(ret);
993 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
994 WARN_ON(ret);
995 ret = register_trace_block_split(blk_add_trace_split, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1000 WARN_ON(ret);
1001 }
1002
1003 static void blk_unregister_tracepoints(void)
1004 {
1005 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1006 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1007 unregister_trace_block_split(blk_add_trace_split, NULL);
1008 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1009 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1010 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1011 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1012 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1013 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1014 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1015 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1016 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1017 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1018 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1019 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1020 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1021
1022 tracepoint_synchronize_unregister();
1023 }
1024
1025 /*
1026 * struct blk_io_tracer formatting routines
1027 */
1028
1029 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1030 {
1031 int i = 0;
1032 int tc = t->action >> BLK_TC_SHIFT;
1033
1034 if (t->action == BLK_TN_MESSAGE) {
1035 rwbs[i++] = 'N';
1036 goto out;
1037 }
1038
1039 if (tc & BLK_TC_FLUSH)
1040 rwbs[i++] = 'F';
1041
1042 if (tc & BLK_TC_DISCARD)
1043 rwbs[i++] = 'D';
1044 else if (tc & BLK_TC_WRITE)
1045 rwbs[i++] = 'W';
1046 else if (t->bytes)
1047 rwbs[i++] = 'R';
1048 else
1049 rwbs[i++] = 'N';
1050
1051 if (tc & BLK_TC_FUA)
1052 rwbs[i++] = 'F';
1053 if (tc & BLK_TC_AHEAD)
1054 rwbs[i++] = 'A';
1055 if (tc & BLK_TC_SYNC)
1056 rwbs[i++] = 'S';
1057 if (tc & BLK_TC_META)
1058 rwbs[i++] = 'M';
1059 out:
1060 rwbs[i] = '\0';
1061 }
1062
1063 static inline
1064 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1065 {
1066 return (const struct blk_io_trace *)ent;
1067 }
1068
1069 static inline const void *pdu_start(const struct trace_entry *ent)
1070 {
1071 return te_blk_io_trace(ent) + 1;
1072 }
1073
1074 static inline u32 t_action(const struct trace_entry *ent)
1075 {
1076 return te_blk_io_trace(ent)->action;
1077 }
1078
1079 static inline u32 t_bytes(const struct trace_entry *ent)
1080 {
1081 return te_blk_io_trace(ent)->bytes;
1082 }
1083
1084 static inline u32 t_sec(const struct trace_entry *ent)
1085 {
1086 return te_blk_io_trace(ent)->bytes >> 9;
1087 }
1088
1089 static inline unsigned long long t_sector(const struct trace_entry *ent)
1090 {
1091 return te_blk_io_trace(ent)->sector;
1092 }
1093
1094 static inline __u16 t_error(const struct trace_entry *ent)
1095 {
1096 return te_blk_io_trace(ent)->error;
1097 }
1098
1099 static __u64 get_pdu_int(const struct trace_entry *ent)
1100 {
1101 const __u64 *val = pdu_start(ent);
1102 return be64_to_cpu(*val);
1103 }
1104
1105 static void get_pdu_remap(const struct trace_entry *ent,
1106 struct blk_io_trace_remap *r)
1107 {
1108 const struct blk_io_trace_remap *__r = pdu_start(ent);
1109 __u64 sector_from = __r->sector_from;
1110
1111 r->device_from = be32_to_cpu(__r->device_from);
1112 r->device_to = be32_to_cpu(__r->device_to);
1113 r->sector_from = be64_to_cpu(sector_from);
1114 }
1115
1116 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1117
1118 static void blk_log_action_classic(struct trace_iterator *iter, const char *act)
1119 {
1120 char rwbs[RWBS_LEN];
1121 unsigned long long ts = iter->ts;
1122 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1123 unsigned secs = (unsigned long)ts;
1124 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1125
1126 fill_rwbs(rwbs, t);
1127
1128 trace_seq_printf(&iter->seq,
1129 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1130 MAJOR(t->device), MINOR(t->device), iter->cpu,
1131 secs, nsec_rem, iter->ent->pid, act, rwbs);
1132 }
1133
1134 static void blk_log_action(struct trace_iterator *iter, const char *act)
1135 {
1136 char rwbs[RWBS_LEN];
1137 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1138
1139 fill_rwbs(rwbs, t);
1140 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1141 MAJOR(t->device), MINOR(t->device), act, rwbs);
1142 }
1143
1144 static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1145 {
1146 const unsigned char *pdu_buf;
1147 int pdu_len;
1148 int i, end;
1149
1150 pdu_buf = pdu_start(ent);
1151 pdu_len = te_blk_io_trace(ent)->pdu_len;
1152
1153 if (!pdu_len)
1154 return;
1155
1156 /* find the last zero that needs to be printed */
1157 for (end = pdu_len - 1; end >= 0; end--)
1158 if (pdu_buf[end])
1159 break;
1160 end++;
1161
1162 trace_seq_putc(s, '(');
1163
1164 for (i = 0; i < pdu_len; i++) {
1165
1166 trace_seq_printf(s, "%s%02x",
1167 i == 0 ? "" : " ", pdu_buf[i]);
1168
1169 /*
1170 * stop when the rest is just zeroes and indicate so
1171 * with a ".." appended
1172 */
1173 if (i == end && end != pdu_len - 1) {
1174 trace_seq_puts(s, " ..) ");
1175 return;
1176 }
1177 }
1178
1179 trace_seq_puts(s, ") ");
1180 }
1181
1182 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1183 {
1184 char cmd[TASK_COMM_LEN];
1185
1186 trace_find_cmdline(ent->pid, cmd);
1187
1188 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1189 trace_seq_printf(s, "%u ", t_bytes(ent));
1190 blk_log_dump_pdu(s, ent);
1191 trace_seq_printf(s, "[%s]\n", cmd);
1192 } else {
1193 if (t_sec(ent))
1194 trace_seq_printf(s, "%llu + %u [%s]\n",
1195 t_sector(ent), t_sec(ent), cmd);
1196 else
1197 trace_seq_printf(s, "[%s]\n", cmd);
1198 }
1199 }
1200
1201 static void blk_log_with_error(struct trace_seq *s,
1202 const struct trace_entry *ent)
1203 {
1204 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1205 blk_log_dump_pdu(s, ent);
1206 trace_seq_printf(s, "[%d]\n", t_error(ent));
1207 } else {
1208 if (t_sec(ent))
1209 trace_seq_printf(s, "%llu + %u [%d]\n",
1210 t_sector(ent),
1211 t_sec(ent), t_error(ent));
1212 else
1213 trace_seq_printf(s, "%llu [%d]\n",
1214 t_sector(ent), t_error(ent));
1215 }
1216 }
1217
1218 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1219 {
1220 struct blk_io_trace_remap r = { .device_from = 0, };
1221
1222 get_pdu_remap(ent, &r);
1223 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1224 t_sector(ent), t_sec(ent),
1225 MAJOR(r.device_from), MINOR(r.device_from),
1226 (unsigned long long)r.sector_from);
1227 }
1228
1229 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1230 {
1231 char cmd[TASK_COMM_LEN];
1232
1233 trace_find_cmdline(ent->pid, cmd);
1234
1235 trace_seq_printf(s, "[%s]\n", cmd);
1236 }
1237
1238 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1239 {
1240 char cmd[TASK_COMM_LEN];
1241
1242 trace_find_cmdline(ent->pid, cmd);
1243
1244 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1245 }
1246
1247 static void blk_log_split(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 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1254 get_pdu_int(ent), cmd);
1255 }
1256
1257 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1258 {
1259 const struct blk_io_trace *t = te_blk_io_trace(ent);
1260
1261 trace_seq_putmem(s, t + 1, t->pdu_len);
1262 trace_seq_putc(s, '\n');
1263 }
1264
1265 /*
1266 * struct tracer operations
1267 */
1268
1269 static void blk_tracer_print_header(struct seq_file *m)
1270 {
1271 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1272 return;
1273 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1274 "# | | | | | |\n");
1275 }
1276
1277 static void blk_tracer_start(struct trace_array *tr)
1278 {
1279 blk_tracer_enabled = true;
1280 }
1281
1282 static int blk_tracer_init(struct trace_array *tr)
1283 {
1284 blk_tr = tr;
1285 blk_tracer_start(tr);
1286 return 0;
1287 }
1288
1289 static void blk_tracer_stop(struct trace_array *tr)
1290 {
1291 blk_tracer_enabled = false;
1292 }
1293
1294 static void blk_tracer_reset(struct trace_array *tr)
1295 {
1296 blk_tracer_stop(tr);
1297 }
1298
1299 static const struct {
1300 const char *act[2];
1301 void (*print)(struct trace_seq *s, const struct trace_entry *ent);
1302 } what2act[] = {
1303 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1304 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1305 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1306 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1307 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1308 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1309 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1310 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1311 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1312 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1313 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1314 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1315 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1316 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1317 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1318 };
1319
1320 static enum print_line_t print_one_line(struct trace_iterator *iter,
1321 bool classic)
1322 {
1323 struct trace_array *tr = iter->tr;
1324 struct trace_seq *s = &iter->seq;
1325 const struct blk_io_trace *t;
1326 u16 what;
1327 bool long_act;
1328 blk_log_action_t *log_action;
1329
1330 t = te_blk_io_trace(iter->ent);
1331 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1332 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1333 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1334
1335 if (t->action == BLK_TN_MESSAGE) {
1336 log_action(iter, long_act ? "message" : "m");
1337 blk_log_msg(s, iter->ent);
1338 return trace_handle_return(s);
1339 }
1340
1341 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1342 trace_seq_printf(s, "Unknown action %x\n", what);
1343 else {
1344 log_action(iter, what2act[what].act[long_act]);
1345 what2act[what].print(s, iter->ent);
1346 }
1347
1348 return trace_handle_return(s);
1349 }
1350
1351 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1352 int flags, struct trace_event *event)
1353 {
1354 return print_one_line(iter, false);
1355 }
1356
1357 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1358 {
1359 struct trace_seq *s = &iter->seq;
1360 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1361 const int offset = offsetof(struct blk_io_trace, sector);
1362 struct blk_io_trace old = {
1363 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1364 .time = iter->ts,
1365 };
1366
1367 trace_seq_putmem(s, &old, offset);
1368 trace_seq_putmem(s, &t->sector,
1369 sizeof(old) - offset + t->pdu_len);
1370 }
1371
1372 static enum print_line_t
1373 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1374 struct trace_event *event)
1375 {
1376 blk_trace_synthesize_old_trace(iter);
1377
1378 return trace_handle_return(&iter->seq);
1379 }
1380
1381 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1382 {
1383 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1384 return TRACE_TYPE_UNHANDLED;
1385
1386 return print_one_line(iter, true);
1387 }
1388
1389 static int
1390 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1391 {
1392 /* don't output context-info for blk_classic output */
1393 if (bit == TRACE_BLK_OPT_CLASSIC) {
1394 if (set)
1395 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1396 else
1397 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1398 }
1399 return 0;
1400 }
1401
1402 static struct tracer blk_tracer __read_mostly = {
1403 .name = "blk",
1404 .init = blk_tracer_init,
1405 .reset = blk_tracer_reset,
1406 .start = blk_tracer_start,
1407 .stop = blk_tracer_stop,
1408 .print_header = blk_tracer_print_header,
1409 .print_line = blk_tracer_print_line,
1410 .flags = &blk_tracer_flags,
1411 .set_flag = blk_tracer_set_flag,
1412 };
1413
1414 static struct trace_event_functions trace_blk_event_funcs = {
1415 .trace = blk_trace_event_print,
1416 .binary = blk_trace_event_print_binary,
1417 };
1418
1419 static struct trace_event trace_blk_event = {
1420 .type = TRACE_BLK,
1421 .funcs = &trace_blk_event_funcs,
1422 };
1423
1424 static int __init init_blk_tracer(void)
1425 {
1426 if (!register_trace_event(&trace_blk_event)) {
1427 pr_warn("Warning: could not register block events\n");
1428 return 1;
1429 }
1430
1431 if (register_tracer(&blk_tracer) != 0) {
1432 pr_warn("Warning: could not register the block tracer\n");
1433 unregister_trace_event(&trace_blk_event);
1434 return 1;
1435 }
1436
1437 return 0;
1438 }
1439
1440 device_initcall(init_blk_tracer);
1441
1442 static int blk_trace_remove_queue(struct request_queue *q)
1443 {
1444 struct blk_trace *bt;
1445
1446 bt = xchg(&q->blk_trace, NULL);
1447 if (bt == NULL)
1448 return -EINVAL;
1449
1450 if (atomic_dec_and_test(&blk_probes_ref))
1451 blk_unregister_tracepoints();
1452
1453 blk_trace_free(bt);
1454 return 0;
1455 }
1456
1457 /*
1458 * Setup everything required to start tracing
1459 */
1460 static int blk_trace_setup_queue(struct request_queue *q,
1461 struct block_device *bdev)
1462 {
1463 struct blk_trace *bt = NULL;
1464 int ret = -ENOMEM;
1465
1466 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1467 if (!bt)
1468 return -ENOMEM;
1469
1470 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1471 if (!bt->msg_data)
1472 goto free_bt;
1473
1474 bt->dev = bdev->bd_dev;
1475 bt->act_mask = (u16)-1;
1476
1477 blk_trace_setup_lba(bt, bdev);
1478
1479 ret = -EBUSY;
1480 if (cmpxchg(&q->blk_trace, NULL, bt))
1481 goto free_bt;
1482
1483 if (atomic_inc_return(&blk_probes_ref) == 1)
1484 blk_register_tracepoints();
1485 return 0;
1486
1487 free_bt:
1488 blk_trace_free(bt);
1489 return ret;
1490 }
1491
1492 /*
1493 * sysfs interface to enable and configure tracing
1494 */
1495
1496 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1497 struct device_attribute *attr,
1498 char *buf);
1499 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1500 struct device_attribute *attr,
1501 const char *buf, size_t count);
1502 #define BLK_TRACE_DEVICE_ATTR(_name) \
1503 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1504 sysfs_blk_trace_attr_show, \
1505 sysfs_blk_trace_attr_store)
1506
1507 static BLK_TRACE_DEVICE_ATTR(enable);
1508 static BLK_TRACE_DEVICE_ATTR(act_mask);
1509 static BLK_TRACE_DEVICE_ATTR(pid);
1510 static BLK_TRACE_DEVICE_ATTR(start_lba);
1511 static BLK_TRACE_DEVICE_ATTR(end_lba);
1512
1513 static struct attribute *blk_trace_attrs[] = {
1514 &dev_attr_enable.attr,
1515 &dev_attr_act_mask.attr,
1516 &dev_attr_pid.attr,
1517 &dev_attr_start_lba.attr,
1518 &dev_attr_end_lba.attr,
1519 NULL
1520 };
1521
1522 struct attribute_group blk_trace_attr_group = {
1523 .name = "trace",
1524 .attrs = blk_trace_attrs,
1525 };
1526
1527 static const struct {
1528 int mask;
1529 const char *str;
1530 } mask_maps[] = {
1531 { BLK_TC_READ, "read" },
1532 { BLK_TC_WRITE, "write" },
1533 { BLK_TC_FLUSH, "flush" },
1534 { BLK_TC_SYNC, "sync" },
1535 { BLK_TC_QUEUE, "queue" },
1536 { BLK_TC_REQUEUE, "requeue" },
1537 { BLK_TC_ISSUE, "issue" },
1538 { BLK_TC_COMPLETE, "complete" },
1539 { BLK_TC_FS, "fs" },
1540 { BLK_TC_PC, "pc" },
1541 { BLK_TC_NOTIFY, "notify" },
1542 { BLK_TC_AHEAD, "ahead" },
1543 { BLK_TC_META, "meta" },
1544 { BLK_TC_DISCARD, "discard" },
1545 { BLK_TC_DRV_DATA, "drv_data" },
1546 { BLK_TC_FUA, "fua" },
1547 };
1548
1549 static int blk_trace_str2mask(const char *str)
1550 {
1551 int i;
1552 int mask = 0;
1553 char *buf, *s, *token;
1554
1555 buf = kstrdup(str, GFP_KERNEL);
1556 if (buf == NULL)
1557 return -ENOMEM;
1558 s = strstrip(buf);
1559
1560 while (1) {
1561 token = strsep(&s, ",");
1562 if (token == NULL)
1563 break;
1564
1565 if (*token == '\0')
1566 continue;
1567
1568 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1569 if (strcasecmp(token, mask_maps[i].str) == 0) {
1570 mask |= mask_maps[i].mask;
1571 break;
1572 }
1573 }
1574 if (i == ARRAY_SIZE(mask_maps)) {
1575 mask = -EINVAL;
1576 break;
1577 }
1578 }
1579 kfree(buf);
1580
1581 return mask;
1582 }
1583
1584 static ssize_t blk_trace_mask2str(char *buf, int mask)
1585 {
1586 int i;
1587 char *p = buf;
1588
1589 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1590 if (mask & mask_maps[i].mask) {
1591 p += sprintf(p, "%s%s",
1592 (p == buf) ? "" : ",", mask_maps[i].str);
1593 }
1594 }
1595 *p++ = '\n';
1596
1597 return p - buf;
1598 }
1599
1600 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1601 {
1602 if (bdev->bd_disk == NULL)
1603 return NULL;
1604
1605 return bdev_get_queue(bdev);
1606 }
1607
1608 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1609 struct device_attribute *attr,
1610 char *buf)
1611 {
1612 struct hd_struct *p = dev_to_part(dev);
1613 struct request_queue *q;
1614 struct block_device *bdev;
1615 ssize_t ret = -ENXIO;
1616
1617 bdev = bdget(part_devt(p));
1618 if (bdev == NULL)
1619 goto out;
1620
1621 q = blk_trace_get_queue(bdev);
1622 if (q == NULL)
1623 goto out_bdput;
1624
1625 mutex_lock(&bdev->bd_mutex);
1626
1627 if (attr == &dev_attr_enable) {
1628 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1629 goto out_unlock_bdev;
1630 }
1631
1632 if (q->blk_trace == NULL)
1633 ret = sprintf(buf, "disabled\n");
1634 else if (attr == &dev_attr_act_mask)
1635 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1636 else if (attr == &dev_attr_pid)
1637 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1638 else if (attr == &dev_attr_start_lba)
1639 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1640 else if (attr == &dev_attr_end_lba)
1641 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1642
1643 out_unlock_bdev:
1644 mutex_unlock(&bdev->bd_mutex);
1645 out_bdput:
1646 bdput(bdev);
1647 out:
1648 return ret;
1649 }
1650
1651 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1652 struct device_attribute *attr,
1653 const char *buf, size_t count)
1654 {
1655 struct block_device *bdev;
1656 struct request_queue *q;
1657 struct hd_struct *p;
1658 u64 value;
1659 ssize_t ret = -EINVAL;
1660
1661 if (count == 0)
1662 goto out;
1663
1664 if (attr == &dev_attr_act_mask) {
1665 if (kstrtoull(buf, 0, &value)) {
1666 /* Assume it is a list of trace category names */
1667 ret = blk_trace_str2mask(buf);
1668 if (ret < 0)
1669 goto out;
1670 value = ret;
1671 }
1672 } else if (kstrtoull(buf, 0, &value))
1673 goto out;
1674
1675 ret = -ENXIO;
1676
1677 p = dev_to_part(dev);
1678 bdev = bdget(part_devt(p));
1679 if (bdev == NULL)
1680 goto out;
1681
1682 q = blk_trace_get_queue(bdev);
1683 if (q == NULL)
1684 goto out_bdput;
1685
1686 mutex_lock(&bdev->bd_mutex);
1687
1688 if (attr == &dev_attr_enable) {
1689 if (value)
1690 ret = blk_trace_setup_queue(q, bdev);
1691 else
1692 ret = blk_trace_remove_queue(q);
1693 goto out_unlock_bdev;
1694 }
1695
1696 ret = 0;
1697 if (q->blk_trace == NULL)
1698 ret = blk_trace_setup_queue(q, bdev);
1699
1700 if (ret == 0) {
1701 if (attr == &dev_attr_act_mask)
1702 q->blk_trace->act_mask = value;
1703 else if (attr == &dev_attr_pid)
1704 q->blk_trace->pid = value;
1705 else if (attr == &dev_attr_start_lba)
1706 q->blk_trace->start_lba = value;
1707 else if (attr == &dev_attr_end_lba)
1708 q->blk_trace->end_lba = value;
1709 }
1710
1711 out_unlock_bdev:
1712 mutex_unlock(&bdev->bd_mutex);
1713 out_bdput:
1714 bdput(bdev);
1715 out:
1716 return ret ? ret : count;
1717 }
1718
1719 int blk_trace_init_sysfs(struct device *dev)
1720 {
1721 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1722 }
1723
1724 void blk_trace_remove_sysfs(struct device *dev)
1725 {
1726 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1727 }
1728
1729 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1730
1731 #ifdef CONFIG_EVENT_TRACING
1732
1733 void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
1734 {
1735 int i = 0;
1736
1737 if (op & REQ_PREFLUSH)
1738 rwbs[i++] = 'F';
1739
1740 switch (op & REQ_OP_MASK) {
1741 case REQ_OP_WRITE:
1742 case REQ_OP_WRITE_SAME:
1743 rwbs[i++] = 'W';
1744 break;
1745 case REQ_OP_DISCARD:
1746 rwbs[i++] = 'D';
1747 break;
1748 case REQ_OP_SECURE_ERASE:
1749 rwbs[i++] = 'D';
1750 rwbs[i++] = 'E';
1751 break;
1752 case REQ_OP_FLUSH:
1753 rwbs[i++] = 'F';
1754 break;
1755 case REQ_OP_READ:
1756 rwbs[i++] = 'R';
1757 break;
1758 default:
1759 rwbs[i++] = 'N';
1760 }
1761
1762 if (op & REQ_FUA)
1763 rwbs[i++] = 'F';
1764 if (op & REQ_RAHEAD)
1765 rwbs[i++] = 'A';
1766 if (op & REQ_SYNC)
1767 rwbs[i++] = 'S';
1768 if (op & REQ_META)
1769 rwbs[i++] = 'M';
1770
1771 rwbs[i] = '\0';
1772 }
1773 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1774
1775 #endif /* CONFIG_EVENT_TRACING */
1776
Linux with added FPC-III support