projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
block, drivers, fs: rename REQ_FLUSH to REQ_PREFLUSH
[deliverable/linux.git] / kernel / trace / blktrace.c
1 /*
2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
16 *
17 */
18 #include <linux/kernel.h>
19 #include <linux/blkdev.h>
20 #include <linux/blktrace_api.h>
21 #include <linux/percpu.h>
22 #include <linux/init.h>
23 #include <linux/mutex.h>
24 #include <linux/slab.h>
25 #include <linux/debugfs.h>
26 #include <linux/export.h>
27 #include <linux/time.h>
28 #include <linux/uaccess.h>
29 #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(blk_tr, 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 #define BLK_TC_PREFLUSH BLK_TC_FLUSH
193
194 /* The ilog2() calls fall out because they're constant */
195 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
196 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
197
198 /*
199 * The worker for the various blk_add_trace*() types. Fills out a
200 * blk_io_trace structure and places it in a per-cpu subbuffer.
201 */
202 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
203 int op, int op_flags, u32 what, int error, int pdu_len,
204 void *pdu_data)
205 {
206 struct task_struct *tsk = current;
207 struct ring_buffer_event *event = NULL;
208 struct ring_buffer *buffer = NULL;
209 struct blk_io_trace *t;
210 unsigned long flags = 0;
211 unsigned long *sequence;
212 pid_t pid;
213 int cpu, pc = 0;
214 bool blk_tracer = blk_tracer_enabled;
215
216 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
217 return;
218
219 what |= ddir_act[op_is_write(op) ? WRITE : READ];
220 what |= MASK_TC_BIT(op_flags, SYNC);
221 what |= MASK_TC_BIT(op_flags, RAHEAD);
222 what |= MASK_TC_BIT(op_flags, META);
223 what |= MASK_TC_BIT(op_flags, PREFLUSH);
224 what |= MASK_TC_BIT(op_flags, FUA);
225 if (op == REQ_OP_DISCARD)
226 what |= BLK_TC_ACT(BLK_TC_DISCARD);
227 if (op == REQ_OP_FLUSH)
228 what |= BLK_TC_ACT(BLK_TC_FLUSH);
229
230 pid = tsk->pid;
231 if (act_log_check(bt, what, sector, pid))
232 return;
233 cpu = raw_smp_processor_id();
234
235 if (blk_tracer) {
236 tracing_record_cmdline(current);
237
238 buffer = blk_tr->trace_buffer.buffer;
239 pc = preempt_count();
240 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
241 sizeof(*t) + pdu_len,
242 0, pc);
243 if (!event)
244 return;
245 t = ring_buffer_event_data(event);
246 goto record_it;
247 }
248
249 if (unlikely(tsk->btrace_seq != blktrace_seq))
250 trace_note_tsk(tsk);
251
252 /*
253 * A word about the locking here - we disable interrupts to reserve
254 * some space in the relay per-cpu buffer, to prevent an irq
255 * from coming in and stepping on our toes.
256 */
257 local_irq_save(flags);
258 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
259 if (t) {
260 sequence = per_cpu_ptr(bt->sequence, cpu);
261
262 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
263 t->sequence = ++(*sequence);
264 t->time = ktime_to_ns(ktime_get());
265 record_it:
266 /*
267 * These two are not needed in ftrace as they are in the
268 * generic trace_entry, filled by tracing_generic_entry_update,
269 * but for the trace_event->bin() synthesizer benefit we do it
270 * here too.
271 */
272 t->cpu = cpu;
273 t->pid = pid;
274
275 t->sector = sector;
276 t->bytes = bytes;
277 t->action = what;
278 t->device = bt->dev;
279 t->error = error;
280 t->pdu_len = pdu_len;
281
282 if (pdu_len)
283 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
284
285 if (blk_tracer) {
286 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
287 return;
288 }
289 }
290
291 local_irq_restore(flags);
292 }
293
294 static struct dentry *blk_tree_root;
295 static DEFINE_MUTEX(blk_tree_mutex);
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 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 mutex_lock(&blk_tree_mutex);
471 if (!blk_tree_root) {
472 blk_tree_root = debugfs_create_dir("block", NULL);
473 if (!blk_tree_root) {
474 mutex_unlock(&blk_tree_mutex);
475 goto err;
476 }
477 }
478 mutex_unlock(&blk_tree_mutex);
479
480 dir = debugfs_create_dir(buts->name, blk_tree_root);
481
482 if (!dir)
483 goto err;
484
485 bt->dir = dir;
486 bt->dev = dev;
487 atomic_set(&bt->dropped, 0);
488 INIT_LIST_HEAD(&bt->running_list);
489
490 ret = -EIO;
491 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
492 &blk_dropped_fops);
493 if (!bt->dropped_file)
494 goto err;
495
496 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
497 if (!bt->msg_file)
498 goto err;
499
500 bt->rchan = relay_open("trace", dir, buts->buf_size,
501 buts->buf_nr, &blk_relay_callbacks, bt);
502 if (!bt->rchan)
503 goto err;
504
505 bt->act_mask = buts->act_mask;
506 if (!bt->act_mask)
507 bt->act_mask = (u16) -1;
508
509 blk_trace_setup_lba(bt, bdev);
510
511 /* overwrite with user settings */
512 if (buts->start_lba)
513 bt->start_lba = buts->start_lba;
514 if (buts->end_lba)
515 bt->end_lba = buts->end_lba;
516
517 bt->pid = buts->pid;
518 bt->trace_state = Blktrace_setup;
519
520 ret = -EBUSY;
521 if (cmpxchg(&q->blk_trace, NULL, bt))
522 goto err;
523
524 if (atomic_inc_return(&blk_probes_ref) == 1)
525 blk_register_tracepoints();
526
527 return 0;
528 err:
529 blk_trace_free(bt);
530 return ret;
531 }
532
533 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
534 struct block_device *bdev,
535 char __user *arg)
536 {
537 struct blk_user_trace_setup buts;
538 int ret;
539
540 ret = copy_from_user(&buts, arg, sizeof(buts));
541 if (ret)
542 return -EFAULT;
543
544 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
545 if (ret)
546 return ret;
547
548 if (copy_to_user(arg, &buts, sizeof(buts))) {
549 blk_trace_remove(q);
550 return -EFAULT;
551 }
552 return 0;
553 }
554 EXPORT_SYMBOL_GPL(blk_trace_setup);
555
556 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
557 static int compat_blk_trace_setup(struct request_queue *q, char *name,
558 dev_t dev, struct block_device *bdev,
559 char __user *arg)
560 {
561 struct blk_user_trace_setup buts;
562 struct compat_blk_user_trace_setup cbuts;
563 int ret;
564
565 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
566 return -EFAULT;
567
568 buts = (struct blk_user_trace_setup) {
569 .act_mask = cbuts.act_mask,
570 .buf_size = cbuts.buf_size,
571 .buf_nr = cbuts.buf_nr,
572 .start_lba = cbuts.start_lba,
573 .end_lba = cbuts.end_lba,
574 .pid = cbuts.pid,
575 };
576
577 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
578 if (ret)
579 return ret;
580
581 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
582 blk_trace_remove(q);
583 return -EFAULT;
584 }
585
586 return 0;
587 }
588 #endif
589
590 int blk_trace_startstop(struct request_queue *q, int start)
591 {
592 int ret;
593 struct blk_trace *bt = q->blk_trace;
594
595 if (bt == NULL)
596 return -EINVAL;
597
598 /*
599 * For starting a trace, we can transition from a setup or stopped
600 * trace. For stopping a trace, the state must be running
601 */
602 ret = -EINVAL;
603 if (start) {
604 if (bt->trace_state == Blktrace_setup ||
605 bt->trace_state == Blktrace_stopped) {
606 blktrace_seq++;
607 smp_mb();
608 bt->trace_state = Blktrace_running;
609 spin_lock_irq(&running_trace_lock);
610 list_add(&bt->running_list, &running_trace_list);
611 spin_unlock_irq(&running_trace_lock);
612
613 trace_note_time(bt);
614 ret = 0;
615 }
616 } else {
617 if (bt->trace_state == Blktrace_running) {
618 bt->trace_state = Blktrace_stopped;
619 spin_lock_irq(&running_trace_lock);
620 list_del_init(&bt->running_list);
621 spin_unlock_irq(&running_trace_lock);
622 relay_flush(bt->rchan);
623 ret = 0;
624 }
625 }
626
627 return ret;
628 }
629 EXPORT_SYMBOL_GPL(blk_trace_startstop);
630
631 /**
632 * blk_trace_ioctl: - handle the ioctls associated with tracing
633 * @bdev: the block device
634 * @cmd: the ioctl cmd
635 * @arg: the argument data, if any
636 *
637 **/
638 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
639 {
640 struct request_queue *q;
641 int ret, start = 0;
642 char b[BDEVNAME_SIZE];
643
644 q = bdev_get_queue(bdev);
645 if (!q)
646 return -ENXIO;
647
648 mutex_lock(&bdev->bd_mutex);
649
650 switch (cmd) {
651 case BLKTRACESETUP:
652 bdevname(bdev, b);
653 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
654 break;
655 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
656 case BLKTRACESETUP32:
657 bdevname(bdev, b);
658 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
659 break;
660 #endif
661 case BLKTRACESTART:
662 start = 1;
663 case BLKTRACESTOP:
664 ret = blk_trace_startstop(q, start);
665 break;
666 case BLKTRACETEARDOWN:
667 ret = blk_trace_remove(q);
668 break;
669 default:
670 ret = -ENOTTY;
671 break;
672 }
673
674 mutex_unlock(&bdev->bd_mutex);
675 return ret;
676 }
677
678 /**
679 * blk_trace_shutdown: - stop and cleanup trace structures
680 * @q: the request queue associated with the device
681 *
682 **/
683 void blk_trace_shutdown(struct request_queue *q)
684 {
685 if (q->blk_trace) {
686 blk_trace_startstop(q, 0);
687 blk_trace_remove(q);
688 }
689 }
690
691 /*
692 * blktrace probes
693 */
694
695 /**
696 * blk_add_trace_rq - Add a trace for a request oriented action
697 * @q: queue the io is for
698 * @rq: the source request
699 * @nr_bytes: number of completed bytes
700 * @what: the action
701 *
702 * Description:
703 * Records an action against a request. Will log the bio offset + size.
704 *
705 **/
706 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
707 unsigned int nr_bytes, u32 what)
708 {
709 struct blk_trace *bt = q->blk_trace;
710
711 if (likely(!bt))
712 return;
713
714 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
715 what |= BLK_TC_ACT(BLK_TC_PC);
716 __blk_add_trace(bt, 0, nr_bytes, req_op(rq), rq->cmd_flags,
717 what, rq->errors, rq->cmd_len, rq->cmd);
718 } else {
719 what |= BLK_TC_ACT(BLK_TC_FS);
720 __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes, req_op(rq),
721 rq->cmd_flags, what, rq->errors, 0, NULL);
722 }
723 }
724
725 static void blk_add_trace_rq_abort(void *ignore,
726 struct request_queue *q, struct request *rq)
727 {
728 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT);
729 }
730
731 static void blk_add_trace_rq_insert(void *ignore,
732 struct request_queue *q, struct request *rq)
733 {
734 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT);
735 }
736
737 static void blk_add_trace_rq_issue(void *ignore,
738 struct request_queue *q, struct request *rq)
739 {
740 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE);
741 }
742
743 static void blk_add_trace_rq_requeue(void *ignore,
744 struct request_queue *q,
745 struct request *rq)
746 {
747 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE);
748 }
749
750 static void blk_add_trace_rq_complete(void *ignore,
751 struct request_queue *q,
752 struct request *rq,
753 unsigned int nr_bytes)
754 {
755 blk_add_trace_rq(q, rq, nr_bytes, BLK_TA_COMPLETE);
756 }
757
758 /**
759 * blk_add_trace_bio - Add a trace for a bio oriented action
760 * @q: queue the io is for
761 * @bio: the source bio
762 * @what: the action
763 * @error: error, if any
764 *
765 * Description:
766 * Records an action against a bio. Will log the bio offset + size.
767 *
768 **/
769 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
770 u32 what, int error)
771 {
772 struct blk_trace *bt = q->blk_trace;
773
774 if (likely(!bt))
775 return;
776
777 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
778 bio_op(bio), bio->bi_rw, what, error, 0, NULL);
779 }
780
781 static void blk_add_trace_bio_bounce(void *ignore,
782 struct request_queue *q, struct bio *bio)
783 {
784 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
785 }
786
787 static void blk_add_trace_bio_complete(void *ignore,
788 struct request_queue *q, struct bio *bio,
789 int error)
790 {
791 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
792 }
793
794 static void blk_add_trace_bio_backmerge(void *ignore,
795 struct request_queue *q,
796 struct request *rq,
797 struct bio *bio)
798 {
799 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
800 }
801
802 static void blk_add_trace_bio_frontmerge(void *ignore,
803 struct request_queue *q,
804 struct request *rq,
805 struct bio *bio)
806 {
807 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
808 }
809
810 static void blk_add_trace_bio_queue(void *ignore,
811 struct request_queue *q, struct bio *bio)
812 {
813 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
814 }
815
816 static void blk_add_trace_getrq(void *ignore,
817 struct request_queue *q,
818 struct bio *bio, int rw)
819 {
820 if (bio)
821 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
822 else {
823 struct blk_trace *bt = q->blk_trace;
824
825 if (bt)
826 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
827 NULL);
828 }
829 }
830
831
832 static void blk_add_trace_sleeprq(void *ignore,
833 struct request_queue *q,
834 struct bio *bio, int rw)
835 {
836 if (bio)
837 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
838 else {
839 struct blk_trace *bt = q->blk_trace;
840
841 if (bt)
842 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
843 0, 0, NULL);
844 }
845 }
846
847 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
848 {
849 struct blk_trace *bt = q->blk_trace;
850
851 if (bt)
852 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
853 }
854
855 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
856 unsigned int depth, bool explicit)
857 {
858 struct blk_trace *bt = q->blk_trace;
859
860 if (bt) {
861 __be64 rpdu = cpu_to_be64(depth);
862 u32 what;
863
864 if (explicit)
865 what = BLK_TA_UNPLUG_IO;
866 else
867 what = BLK_TA_UNPLUG_TIMER;
868
869 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
870 }
871 }
872
873 static void blk_add_trace_split(void *ignore,
874 struct request_queue *q, struct bio *bio,
875 unsigned int pdu)
876 {
877 struct blk_trace *bt = q->blk_trace;
878
879 if (bt) {
880 __be64 rpdu = cpu_to_be64(pdu);
881
882 __blk_add_trace(bt, bio->bi_iter.bi_sector,
883 bio->bi_iter.bi_size, bio_op(bio), bio->bi_rw,
884 BLK_TA_SPLIT, bio->bi_error, sizeof(rpdu),
885 &rpdu);
886 }
887 }
888
889 /**
890 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
891 * @ignore: trace callback data parameter (not used)
892 * @q: queue the io is for
893 * @bio: the source bio
894 * @dev: target device
895 * @from: source sector
896 *
897 * Description:
898 * Device mapper or raid target sometimes need to split a bio because
899 * it spans a stripe (or similar). Add a trace for that action.
900 *
901 **/
902 static void blk_add_trace_bio_remap(void *ignore,
903 struct request_queue *q, struct bio *bio,
904 dev_t dev, sector_t from)
905 {
906 struct blk_trace *bt = q->blk_trace;
907 struct blk_io_trace_remap r;
908
909 if (likely(!bt))
910 return;
911
912 r.device_from = cpu_to_be32(dev);
913 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
914 r.sector_from = cpu_to_be64(from);
915
916 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
917 bio_op(bio), bio->bi_rw, BLK_TA_REMAP, bio->bi_error,
918 sizeof(r), &r);
919 }
920
921 /**
922 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
923 * @ignore: trace callback data parameter (not used)
924 * @q: queue the io is for
925 * @rq: the source request
926 * @dev: target device
927 * @from: source sector
928 *
929 * Description:
930 * Device mapper remaps request to other devices.
931 * Add a trace for that action.
932 *
933 **/
934 static void blk_add_trace_rq_remap(void *ignore,
935 struct request_queue *q,
936 struct request *rq, dev_t dev,
937 sector_t from)
938 {
939 struct blk_trace *bt = q->blk_trace;
940 struct blk_io_trace_remap r;
941
942 if (likely(!bt))
943 return;
944
945 r.device_from = cpu_to_be32(dev);
946 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
947 r.sector_from = cpu_to_be64(from);
948
949 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
950 rq_data_dir(rq), 0, BLK_TA_REMAP, !!rq->errors,
951 sizeof(r), &r);
952 }
953
954 /**
955 * blk_add_driver_data - Add binary message with driver-specific data
956 * @q: queue the io is for
957 * @rq: io request
958 * @data: driver-specific data
959 * @len: length of driver-specific data
960 *
961 * Description:
962 * Some drivers might want to write driver-specific data per request.
963 *
964 **/
965 void blk_add_driver_data(struct request_queue *q,
966 struct request *rq,
967 void *data, size_t len)
968 {
969 struct blk_trace *bt = q->blk_trace;
970
971 if (likely(!bt))
972 return;
973
974 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
975 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 0,
976 BLK_TA_DRV_DATA, rq->errors, len, data);
977 else
978 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 0,
979 BLK_TA_DRV_DATA, rq->errors, len, data);
980 }
981 EXPORT_SYMBOL_GPL(blk_add_driver_data);
982
983 static void blk_register_tracepoints(void)
984 {
985 int ret;
986
987 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
988 WARN_ON(ret);
989 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
990 WARN_ON(ret);
991 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
992 WARN_ON(ret);
993 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
994 WARN_ON(ret);
995 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1006 WARN_ON(ret);
1007 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1008 WARN_ON(ret);
1009 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1010 WARN_ON(ret);
1011 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1012 WARN_ON(ret);
1013 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1014 WARN_ON(ret);
1015 ret = register_trace_block_split(blk_add_trace_split, NULL);
1016 WARN_ON(ret);
1017 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1018 WARN_ON(ret);
1019 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1020 WARN_ON(ret);
1021 }
1022
1023 static void blk_unregister_tracepoints(void)
1024 {
1025 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1026 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1027 unregister_trace_block_split(blk_add_trace_split, NULL);
1028 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1029 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1030 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1031 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1032 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1033 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1034 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1035 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1036 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1037 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1038 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1039 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1040 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1041 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1042
1043 tracepoint_synchronize_unregister();
1044 }
1045
1046 /*
1047 * struct blk_io_tracer formatting routines
1048 */
1049
1050 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1051 {
1052 int i = 0;
1053 int tc = t->action >> BLK_TC_SHIFT;
1054
1055 if (t->action == BLK_TN_MESSAGE) {
1056 rwbs[i++] = 'N';
1057 goto out;
1058 }
1059
1060 if (tc & BLK_TC_FLUSH)
1061 rwbs[i++] = 'F';
1062
1063 if (tc & BLK_TC_DISCARD)
1064 rwbs[i++] = 'D';
1065 else if (tc & BLK_TC_WRITE)
1066 rwbs[i++] = 'W';
1067 else if (t->bytes)
1068 rwbs[i++] = 'R';
1069 else
1070 rwbs[i++] = 'N';
1071
1072 if (tc & BLK_TC_FUA)
1073 rwbs[i++] = 'F';
1074 if (tc & BLK_TC_AHEAD)
1075 rwbs[i++] = 'A';
1076 if (tc & BLK_TC_SYNC)
1077 rwbs[i++] = 'S';
1078 if (tc & BLK_TC_META)
1079 rwbs[i++] = 'M';
1080 out:
1081 rwbs[i] = '\0';
1082 }
1083
1084 static inline
1085 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1086 {
1087 return (const struct blk_io_trace *)ent;
1088 }
1089
1090 static inline const void *pdu_start(const struct trace_entry *ent)
1091 {
1092 return te_blk_io_trace(ent) + 1;
1093 }
1094
1095 static inline u32 t_action(const struct trace_entry *ent)
1096 {
1097 return te_blk_io_trace(ent)->action;
1098 }
1099
1100 static inline u32 t_bytes(const struct trace_entry *ent)
1101 {
1102 return te_blk_io_trace(ent)->bytes;
1103 }
1104
1105 static inline u32 t_sec(const struct trace_entry *ent)
1106 {
1107 return te_blk_io_trace(ent)->bytes >> 9;
1108 }
1109
1110 static inline unsigned long long t_sector(const struct trace_entry *ent)
1111 {
1112 return te_blk_io_trace(ent)->sector;
1113 }
1114
1115 static inline __u16 t_error(const struct trace_entry *ent)
1116 {
1117 return te_blk_io_trace(ent)->error;
1118 }
1119
1120 static __u64 get_pdu_int(const struct trace_entry *ent)
1121 {
1122 const __u64 *val = pdu_start(ent);
1123 return be64_to_cpu(*val);
1124 }
1125
1126 static void get_pdu_remap(const struct trace_entry *ent,
1127 struct blk_io_trace_remap *r)
1128 {
1129 const struct blk_io_trace_remap *__r = pdu_start(ent);
1130 __u64 sector_from = __r->sector_from;
1131
1132 r->device_from = be32_to_cpu(__r->device_from);
1133 r->device_to = be32_to_cpu(__r->device_to);
1134 r->sector_from = be64_to_cpu(sector_from);
1135 }
1136
1137 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1138
1139 static void blk_log_action_classic(struct trace_iterator *iter, const char *act)
1140 {
1141 char rwbs[RWBS_LEN];
1142 unsigned long long ts = iter->ts;
1143 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1144 unsigned secs = (unsigned long)ts;
1145 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1146
1147 fill_rwbs(rwbs, t);
1148
1149 trace_seq_printf(&iter->seq,
1150 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1151 MAJOR(t->device), MINOR(t->device), iter->cpu,
1152 secs, nsec_rem, iter->ent->pid, act, rwbs);
1153 }
1154
1155 static void blk_log_action(struct trace_iterator *iter, const char *act)
1156 {
1157 char rwbs[RWBS_LEN];
1158 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1159
1160 fill_rwbs(rwbs, t);
1161 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1162 MAJOR(t->device), MINOR(t->device), act, rwbs);
1163 }
1164
1165 static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1166 {
1167 const unsigned char *pdu_buf;
1168 int pdu_len;
1169 int i, end;
1170
1171 pdu_buf = pdu_start(ent);
1172 pdu_len = te_blk_io_trace(ent)->pdu_len;
1173
1174 if (!pdu_len)
1175 return;
1176
1177 /* find the last zero that needs to be printed */
1178 for (end = pdu_len - 1; end >= 0; end--)
1179 if (pdu_buf[end])
1180 break;
1181 end++;
1182
1183 trace_seq_putc(s, '(');
1184
1185 for (i = 0; i < pdu_len; i++) {
1186
1187 trace_seq_printf(s, "%s%02x",
1188 i == 0 ? "" : " ", pdu_buf[i]);
1189
1190 /*
1191 * stop when the rest is just zeroes and indicate so
1192 * with a ".." appended
1193 */
1194 if (i == end && end != pdu_len - 1) {
1195 trace_seq_puts(s, " ..) ");
1196 return;
1197 }
1198 }
1199
1200 trace_seq_puts(s, ") ");
1201 }
1202
1203 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1204 {
1205 char cmd[TASK_COMM_LEN];
1206
1207 trace_find_cmdline(ent->pid, cmd);
1208
1209 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1210 trace_seq_printf(s, "%u ", t_bytes(ent));
1211 blk_log_dump_pdu(s, ent);
1212 trace_seq_printf(s, "[%s]\n", cmd);
1213 } else {
1214 if (t_sec(ent))
1215 trace_seq_printf(s, "%llu + %u [%s]\n",
1216 t_sector(ent), t_sec(ent), cmd);
1217 else
1218 trace_seq_printf(s, "[%s]\n", cmd);
1219 }
1220 }
1221
1222 static void blk_log_with_error(struct trace_seq *s,
1223 const struct trace_entry *ent)
1224 {
1225 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1226 blk_log_dump_pdu(s, ent);
1227 trace_seq_printf(s, "[%d]\n", t_error(ent));
1228 } else {
1229 if (t_sec(ent))
1230 trace_seq_printf(s, "%llu + %u [%d]\n",
1231 t_sector(ent),
1232 t_sec(ent), t_error(ent));
1233 else
1234 trace_seq_printf(s, "%llu [%d]\n",
1235 t_sector(ent), t_error(ent));
1236 }
1237 }
1238
1239 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1240 {
1241 struct blk_io_trace_remap r = { .device_from = 0, };
1242
1243 get_pdu_remap(ent, &r);
1244 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1245 t_sector(ent), t_sec(ent),
1246 MAJOR(r.device_from), MINOR(r.device_from),
1247 (unsigned long long)r.sector_from);
1248 }
1249
1250 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1251 {
1252 char cmd[TASK_COMM_LEN];
1253
1254 trace_find_cmdline(ent->pid, cmd);
1255
1256 trace_seq_printf(s, "[%s]\n", cmd);
1257 }
1258
1259 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1260 {
1261 char cmd[TASK_COMM_LEN];
1262
1263 trace_find_cmdline(ent->pid, cmd);
1264
1265 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1266 }
1267
1268 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1269 {
1270 char cmd[TASK_COMM_LEN];
1271
1272 trace_find_cmdline(ent->pid, cmd);
1273
1274 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1275 get_pdu_int(ent), cmd);
1276 }
1277
1278 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1279 {
1280 const struct blk_io_trace *t = te_blk_io_trace(ent);
1281
1282 trace_seq_putmem(s, t + 1, t->pdu_len);
1283 trace_seq_putc(s, '\n');
1284 }
1285
1286 /*
1287 * struct tracer operations
1288 */
1289
1290 static void blk_tracer_print_header(struct seq_file *m)
1291 {
1292 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1293 return;
1294 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1295 "# | | | | | |\n");
1296 }
1297
1298 static void blk_tracer_start(struct trace_array *tr)
1299 {
1300 blk_tracer_enabled = true;
1301 }
1302
1303 static int blk_tracer_init(struct trace_array *tr)
1304 {
1305 blk_tr = tr;
1306 blk_tracer_start(tr);
1307 return 0;
1308 }
1309
1310 static void blk_tracer_stop(struct trace_array *tr)
1311 {
1312 blk_tracer_enabled = false;
1313 }
1314
1315 static void blk_tracer_reset(struct trace_array *tr)
1316 {
1317 blk_tracer_stop(tr);
1318 }
1319
1320 static const struct {
1321 const char *act[2];
1322 void (*print)(struct trace_seq *s, const struct trace_entry *ent);
1323 } what2act[] = {
1324 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1325 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1326 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1327 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1328 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1329 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1330 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1331 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1332 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1333 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1334 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1335 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1336 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1337 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1338 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1339 };
1340
1341 static enum print_line_t print_one_line(struct trace_iterator *iter,
1342 bool classic)
1343 {
1344 struct trace_array *tr = iter->tr;
1345 struct trace_seq *s = &iter->seq;
1346 const struct blk_io_trace *t;
1347 u16 what;
1348 bool long_act;
1349 blk_log_action_t *log_action;
1350
1351 t = te_blk_io_trace(iter->ent);
1352 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1353 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1354 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1355
1356 if (t->action == BLK_TN_MESSAGE) {
1357 log_action(iter, long_act ? "message" : "m");
1358 blk_log_msg(s, iter->ent);
1359 return trace_handle_return(s);
1360 }
1361
1362 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1363 trace_seq_printf(s, "Unknown action %x\n", what);
1364 else {
1365 log_action(iter, what2act[what].act[long_act]);
1366 what2act[what].print(s, iter->ent);
1367 }
1368
1369 return trace_handle_return(s);
1370 }
1371
1372 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1373 int flags, struct trace_event *event)
1374 {
1375 return print_one_line(iter, false);
1376 }
1377
1378 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1379 {
1380 struct trace_seq *s = &iter->seq;
1381 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1382 const int offset = offsetof(struct blk_io_trace, sector);
1383 struct blk_io_trace old = {
1384 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1385 .time = iter->ts,
1386 };
1387
1388 trace_seq_putmem(s, &old, offset);
1389 trace_seq_putmem(s, &t->sector,
1390 sizeof(old) - offset + t->pdu_len);
1391 }
1392
1393 static enum print_line_t
1394 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1395 struct trace_event *event)
1396 {
1397 blk_trace_synthesize_old_trace(iter);
1398
1399 return trace_handle_return(&iter->seq);
1400 }
1401
1402 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1403 {
1404 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1405 return TRACE_TYPE_UNHANDLED;
1406
1407 return print_one_line(iter, true);
1408 }
1409
1410 static int
1411 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1412 {
1413 /* don't output context-info for blk_classic output */
1414 if (bit == TRACE_BLK_OPT_CLASSIC) {
1415 if (set)
1416 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1417 else
1418 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1419 }
1420 return 0;
1421 }
1422
1423 static struct tracer blk_tracer __read_mostly = {
1424 .name = "blk",
1425 .init = blk_tracer_init,
1426 .reset = blk_tracer_reset,
1427 .start = blk_tracer_start,
1428 .stop = blk_tracer_stop,
1429 .print_header = blk_tracer_print_header,
1430 .print_line = blk_tracer_print_line,
1431 .flags = &blk_tracer_flags,
1432 .set_flag = blk_tracer_set_flag,
1433 };
1434
1435 static struct trace_event_functions trace_blk_event_funcs = {
1436 .trace = blk_trace_event_print,
1437 .binary = blk_trace_event_print_binary,
1438 };
1439
1440 static struct trace_event trace_blk_event = {
1441 .type = TRACE_BLK,
1442 .funcs = &trace_blk_event_funcs,
1443 };
1444
1445 static int __init init_blk_tracer(void)
1446 {
1447 if (!register_trace_event(&trace_blk_event)) {
1448 pr_warn("Warning: could not register block events\n");
1449 return 1;
1450 }
1451
1452 if (register_tracer(&blk_tracer) != 0) {
1453 pr_warn("Warning: could not register the block tracer\n");
1454 unregister_trace_event(&trace_blk_event);
1455 return 1;
1456 }
1457
1458 return 0;
1459 }
1460
1461 device_initcall(init_blk_tracer);
1462
1463 static int blk_trace_remove_queue(struct request_queue *q)
1464 {
1465 struct blk_trace *bt;
1466
1467 bt = xchg(&q->blk_trace, NULL);
1468 if (bt == NULL)
1469 return -EINVAL;
1470
1471 if (atomic_dec_and_test(&blk_probes_ref))
1472 blk_unregister_tracepoints();
1473
1474 blk_trace_free(bt);
1475 return 0;
1476 }
1477
1478 /*
1479 * Setup everything required to start tracing
1480 */
1481 static int blk_trace_setup_queue(struct request_queue *q,
1482 struct block_device *bdev)
1483 {
1484 struct blk_trace *bt = NULL;
1485 int ret = -ENOMEM;
1486
1487 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1488 if (!bt)
1489 return -ENOMEM;
1490
1491 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1492 if (!bt->msg_data)
1493 goto free_bt;
1494
1495 bt->dev = bdev->bd_dev;
1496 bt->act_mask = (u16)-1;
1497
1498 blk_trace_setup_lba(bt, bdev);
1499
1500 ret = -EBUSY;
1501 if (cmpxchg(&q->blk_trace, NULL, bt))
1502 goto free_bt;
1503
1504 if (atomic_inc_return(&blk_probes_ref) == 1)
1505 blk_register_tracepoints();
1506 return 0;
1507
1508 free_bt:
1509 blk_trace_free(bt);
1510 return ret;
1511 }
1512
1513 /*
1514 * sysfs interface to enable and configure tracing
1515 */
1516
1517 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1518 struct device_attribute *attr,
1519 char *buf);
1520 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1521 struct device_attribute *attr,
1522 const char *buf, size_t count);
1523 #define BLK_TRACE_DEVICE_ATTR(_name) \
1524 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1525 sysfs_blk_trace_attr_show, \
1526 sysfs_blk_trace_attr_store)
1527
1528 static BLK_TRACE_DEVICE_ATTR(enable);
1529 static BLK_TRACE_DEVICE_ATTR(act_mask);
1530 static BLK_TRACE_DEVICE_ATTR(pid);
1531 static BLK_TRACE_DEVICE_ATTR(start_lba);
1532 static BLK_TRACE_DEVICE_ATTR(end_lba);
1533
1534 static struct attribute *blk_trace_attrs[] = {
1535 &dev_attr_enable.attr,
1536 &dev_attr_act_mask.attr,
1537 &dev_attr_pid.attr,
1538 &dev_attr_start_lba.attr,
1539 &dev_attr_end_lba.attr,
1540 NULL
1541 };
1542
1543 struct attribute_group blk_trace_attr_group = {
1544 .name = "trace",
1545 .attrs = blk_trace_attrs,
1546 };
1547
1548 static const struct {
1549 int mask;
1550 const char *str;
1551 } mask_maps[] = {
1552 { BLK_TC_READ, "read" },
1553 { BLK_TC_WRITE, "write" },
1554 { BLK_TC_FLUSH, "flush" },
1555 { BLK_TC_SYNC, "sync" },
1556 { BLK_TC_QUEUE, "queue" },
1557 { BLK_TC_REQUEUE, "requeue" },
1558 { BLK_TC_ISSUE, "issue" },
1559 { BLK_TC_COMPLETE, "complete" },
1560 { BLK_TC_FS, "fs" },
1561 { BLK_TC_PC, "pc" },
1562 { BLK_TC_NOTIFY, "notify" },
1563 { BLK_TC_AHEAD, "ahead" },
1564 { BLK_TC_META, "meta" },
1565 { BLK_TC_DISCARD, "discard" },
1566 { BLK_TC_DRV_DATA, "drv_data" },
1567 { BLK_TC_FUA, "fua" },
1568 };
1569
1570 static int blk_trace_str2mask(const char *str)
1571 {
1572 int i;
1573 int mask = 0;
1574 char *buf, *s, *token;
1575
1576 buf = kstrdup(str, GFP_KERNEL);
1577 if (buf == NULL)
1578 return -ENOMEM;
1579 s = strstrip(buf);
1580
1581 while (1) {
1582 token = strsep(&s, ",");
1583 if (token == NULL)
1584 break;
1585
1586 if (*token == '\0')
1587 continue;
1588
1589 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1590 if (strcasecmp(token, mask_maps[i].str) == 0) {
1591 mask |= mask_maps[i].mask;
1592 break;
1593 }
1594 }
1595 if (i == ARRAY_SIZE(mask_maps)) {
1596 mask = -EINVAL;
1597 break;
1598 }
1599 }
1600 kfree(buf);
1601
1602 return mask;
1603 }
1604
1605 static ssize_t blk_trace_mask2str(char *buf, int mask)
1606 {
1607 int i;
1608 char *p = buf;
1609
1610 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1611 if (mask & mask_maps[i].mask) {
1612 p += sprintf(p, "%s%s",
1613 (p == buf) ? "" : ",", mask_maps[i].str);
1614 }
1615 }
1616 *p++ = '\n';
1617
1618 return p - buf;
1619 }
1620
1621 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1622 {
1623 if (bdev->bd_disk == NULL)
1624 return NULL;
1625
1626 return bdev_get_queue(bdev);
1627 }
1628
1629 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1630 struct device_attribute *attr,
1631 char *buf)
1632 {
1633 struct hd_struct *p = dev_to_part(dev);
1634 struct request_queue *q;
1635 struct block_device *bdev;
1636 ssize_t ret = -ENXIO;
1637
1638 bdev = bdget(part_devt(p));
1639 if (bdev == NULL)
1640 goto out;
1641
1642 q = blk_trace_get_queue(bdev);
1643 if (q == NULL)
1644 goto out_bdput;
1645
1646 mutex_lock(&bdev->bd_mutex);
1647
1648 if (attr == &dev_attr_enable) {
1649 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1650 goto out_unlock_bdev;
1651 }
1652
1653 if (q->blk_trace == NULL)
1654 ret = sprintf(buf, "disabled\n");
1655 else if (attr == &dev_attr_act_mask)
1656 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1657 else if (attr == &dev_attr_pid)
1658 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1659 else if (attr == &dev_attr_start_lba)
1660 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1661 else if (attr == &dev_attr_end_lba)
1662 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1663
1664 out_unlock_bdev:
1665 mutex_unlock(&bdev->bd_mutex);
1666 out_bdput:
1667 bdput(bdev);
1668 out:
1669 return ret;
1670 }
1671
1672 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1673 struct device_attribute *attr,
1674 const char *buf, size_t count)
1675 {
1676 struct block_device *bdev;
1677 struct request_queue *q;
1678 struct hd_struct *p;
1679 u64 value;
1680 ssize_t ret = -EINVAL;
1681
1682 if (count == 0)
1683 goto out;
1684
1685 if (attr == &dev_attr_act_mask) {
1686 if (sscanf(buf, "%llx", &value) != 1) {
1687 /* Assume it is a list of trace category names */
1688 ret = blk_trace_str2mask(buf);
1689 if (ret < 0)
1690 goto out;
1691 value = ret;
1692 }
1693 } else if (sscanf(buf, "%llu", &value) != 1)
1694 goto out;
1695
1696 ret = -ENXIO;
1697
1698 p = dev_to_part(dev);
1699 bdev = bdget(part_devt(p));
1700 if (bdev == NULL)
1701 goto out;
1702
1703 q = blk_trace_get_queue(bdev);
1704 if (q == NULL)
1705 goto out_bdput;
1706
1707 mutex_lock(&bdev->bd_mutex);
1708
1709 if (attr == &dev_attr_enable) {
1710 if (value)
1711 ret = blk_trace_setup_queue(q, bdev);
1712 else
1713 ret = blk_trace_remove_queue(q);
1714 goto out_unlock_bdev;
1715 }
1716
1717 ret = 0;
1718 if (q->blk_trace == NULL)
1719 ret = blk_trace_setup_queue(q, bdev);
1720
1721 if (ret == 0) {
1722 if (attr == &dev_attr_act_mask)
1723 q->blk_trace->act_mask = value;
1724 else if (attr == &dev_attr_pid)
1725 q->blk_trace->pid = value;
1726 else if (attr == &dev_attr_start_lba)
1727 q->blk_trace->start_lba = value;
1728 else if (attr == &dev_attr_end_lba)
1729 q->blk_trace->end_lba = value;
1730 }
1731
1732 out_unlock_bdev:
1733 mutex_unlock(&bdev->bd_mutex);
1734 out_bdput:
1735 bdput(bdev);
1736 out:
1737 return ret ? ret : count;
1738 }
1739
1740 int blk_trace_init_sysfs(struct device *dev)
1741 {
1742 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1743 }
1744
1745 void blk_trace_remove_sysfs(struct device *dev)
1746 {
1747 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1748 }
1749
1750 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1751
1752 #ifdef CONFIG_EVENT_TRACING
1753
1754 void blk_dump_cmd(char *buf, struct request *rq)
1755 {
1756 int i, end;
1757 int len = rq->cmd_len;
1758 unsigned char *cmd = rq->cmd;
1759
1760 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1761 buf[0] = '\0';
1762 return;
1763 }
1764
1765 for (end = len - 1; end >= 0; end--)
1766 if (cmd[end])
1767 break;
1768 end++;
1769
1770 for (i = 0; i < len; i++) {
1771 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1772 if (i == end && end != len - 1) {
1773 sprintf(buf, " ..");
1774 break;
1775 }
1776 }
1777 }
1778
1779 void blk_fill_rwbs(char *rwbs, int op, u32 rw, int bytes)
1780 {
1781 int i = 0;
1782
1783 if (rw & REQ_PREFLUSH)
1784 rwbs[i++] = 'F';
1785
1786 switch (op) {
1787 case REQ_OP_WRITE:
1788 case REQ_OP_WRITE_SAME:
1789 rwbs[i++] = 'W';
1790 break;
1791 case REQ_OP_DISCARD:
1792 rwbs[i++] = 'D';
1793 break;
1794 case REQ_OP_FLUSH:
1795 rwbs[i++] = 'F';
1796 break;
1797 case REQ_OP_READ:
1798 rwbs[i++] = 'R';
1799 break;
1800 default:
1801 rwbs[i++] = 'N';
1802 }
1803
1804 if (rw & REQ_FUA)
1805 rwbs[i++] = 'F';
1806 if (rw & REQ_RAHEAD)
1807 rwbs[i++] = 'A';
1808 if (rw & REQ_SYNC)
1809 rwbs[i++] = 'S';
1810 if (rw & REQ_META)
1811 rwbs[i++] = 'M';
1812 if (rw & REQ_SECURE)
1813 rwbs[i++] = 'E';
1814
1815 rwbs[i] = '\0';
1816 }
1817 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1818
1819 #endif /* CONFIG_EVENT_TRACING */
1820
Linux kernel - Deliverables
This page took 0.086918 seconds and 5 git commands to generate.