projects/linux·blob v4.8 · refs

1823 lines · 42.6 KiB

1/*
2 * Copyright (C) 2006 Jens Axboe <[email protected]>
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
37static unsigned int blktrace_seq __read_mostly = 1;
38
39static struct trace_array *blk_tr;
40static bool blk_tracer_enabled __read_mostly;
41
42static LIST_HEAD(running_trace_list);
43static __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
48static struct tracer_opt blk_tracer_opts[] = {
49 /* Default disable the minimalistic output */
50 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
51 { }
52};
53
54static struct tracer_flags blk_tracer_flags = {
55 .val = 0,
56 .opts = blk_tracer_opts,
57};
58
59/* Global reference count of probes */
60static atomic_t blk_probes_ref = ATOMIC_INIT(0);
61
62static void blk_register_tracepoints(void);
63static void blk_unregister_tracepoints(void);
64
65/*
66 * Send out a notify message.
67 */
68static 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());
97record_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 */
114static 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
128static void trace_note_time(struct blk_trace *bt)
129{
130 struct timespec64 now;
131 unsigned long flags;
132 u32 words[2];
133
134 /* need to check user space to see if this breaks in y2038 or y2106 */
135 ktime_get_real_ts64(&now);
136 words[0] = (u32)now.tv_sec;
137 words[1] = now.tv_nsec;
138
139 local_irq_save(flags);
140 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
141 local_irq_restore(flags);
142}
143
144void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
145{
146 int n;
147 va_list args;
148 unsigned long flags;
149 char *buf;
150
151 if (unlikely(bt->trace_state != Blktrace_running &&
152 !blk_tracer_enabled))
153 return;
154
155 /*
156 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
157 * message to the trace.
158 */
159 if (!(bt->act_mask & BLK_TC_NOTIFY))
160 return;
161
162 local_irq_save(flags);
163 buf = this_cpu_ptr(bt->msg_data);
164 va_start(args, fmt);
165 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
166 va_end(args);
167
168 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
169 local_irq_restore(flags);
170}
171EXPORT_SYMBOL_GPL(__trace_note_message);
172
173static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
174 pid_t pid)
175{
176 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
177 return 1;
178 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
179 return 1;
180 if (bt->pid && pid != bt->pid)
181 return 1;
182
183 return 0;
184}
185
186/*
187 * Data direction bit lookup
188 */
189static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
190 BLK_TC_ACT(BLK_TC_WRITE) };
191
192#define BLK_TC_RAHEAD BLK_TC_AHEAD
193#define BLK_TC_PREFLUSH BLK_TC_FLUSH
194
195/* The ilog2() calls fall out because they're constant */
196#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
197 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
198
199/*
200 * The worker for the various blk_add_trace*() types. Fills out a
201 * blk_io_trace structure and places it in a per-cpu subbuffer.
202 */
203static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
204 int op, int op_flags, u32 what, int error, int pdu_len,
205 void *pdu_data)
206{
207 struct task_struct *tsk = current;
208 struct ring_buffer_event *event = NULL;
209 struct ring_buffer *buffer = NULL;
210 struct blk_io_trace *t;
211 unsigned long flags = 0;
212 unsigned long *sequence;
213 pid_t pid;
214 int cpu, pc = 0;
215 bool blk_tracer = blk_tracer_enabled;
216
217 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
218 return;
219
220 what |= ddir_act[op_is_write(op) ? WRITE : READ];
221 what |= MASK_TC_BIT(op_flags, SYNC);
222 what |= MASK_TC_BIT(op_flags, RAHEAD);
223 what |= MASK_TC_BIT(op_flags, META);
224 what |= MASK_TC_BIT(op_flags, PREFLUSH);
225 what |= MASK_TC_BIT(op_flags, FUA);
226 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
227 what |= BLK_TC_ACT(BLK_TC_DISCARD);
228 if (op == REQ_OP_FLUSH)
229 what |= BLK_TC_ACT(BLK_TC_FLUSH);
230
231 pid = tsk->pid;
232 if (act_log_check(bt, what, sector, pid))
233 return;
234 cpu = raw_smp_processor_id();
235
236 if (blk_tracer) {
237 tracing_record_cmdline(current);
238
239 buffer = blk_tr->trace_buffer.buffer;
240 pc = preempt_count();
241 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
242 sizeof(*t) + pdu_len,
243 0, pc);
244 if (!event)
245 return;
246 t = ring_buffer_event_data(event);
247 goto record_it;
248 }
249
250 if (unlikely(tsk->btrace_seq != blktrace_seq))
251 trace_note_tsk(tsk);
252
253 /*
254 * A word about the locking here - we disable interrupts to reserve
255 * some space in the relay per-cpu buffer, to prevent an irq
256 * from coming in and stepping on our toes.
257 */
258 local_irq_save(flags);
259 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
260 if (t) {
261 sequence = per_cpu_ptr(bt->sequence, cpu);
262
263 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
264 t->sequence = ++(*sequence);
265 t->time = ktime_to_ns(ktime_get());
266record_it:
267 /*
268 * These two are not needed in ftrace as they are in the
269 * generic trace_entry, filled by tracing_generic_entry_update,
270 * but for the trace_event->bin() synthesizer benefit we do it
271 * here too.
272 */
273 t->cpu = cpu;
274 t->pid = pid;
275
276 t->sector = sector;
277 t->bytes = bytes;
278 t->action = what;
279 t->device = bt->dev;
280 t->error = error;
281 t->pdu_len = pdu_len;
282
283 if (pdu_len)
284 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
285
286 if (blk_tracer) {
287 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
288 return;
289 }
290 }
291
292 local_irq_restore(flags);
293}
294
295static struct dentry *blk_tree_root;
296static DEFINE_MUTEX(blk_tree_mutex);
297
298static void blk_trace_free(struct blk_trace *bt)
299{
300 debugfs_remove(bt->msg_file);
301 debugfs_remove(bt->dropped_file);
302 relay_close(bt->rchan);
303 debugfs_remove(bt->dir);
304 free_percpu(bt->sequence);
305 free_percpu(bt->msg_data);
306 kfree(bt);
307}
308
309static void blk_trace_cleanup(struct blk_trace *bt)
310{
311 blk_trace_free(bt);
312 if (atomic_dec_and_test(&blk_probes_ref))
313 blk_unregister_tracepoints();
314}
315
316int blk_trace_remove(struct request_queue *q)
317{
318 struct blk_trace *bt;
319
320 bt = xchg(&q->blk_trace, NULL);
321 if (!bt)
322 return -EINVAL;
323
324 if (bt->trace_state != Blktrace_running)
325 blk_trace_cleanup(bt);
326
327 return 0;
328}
329EXPORT_SYMBOL_GPL(blk_trace_remove);
330
331static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
332 size_t count, loff_t *ppos)
333{
334 struct blk_trace *bt = filp->private_data;
335 char buf[16];
336
337 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
338
339 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
340}
341
342static const struct file_operations blk_dropped_fops = {
343 .owner = THIS_MODULE,
344 .open = simple_open,
345 .read = blk_dropped_read,
346 .llseek = default_llseek,
347};
348
349static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
350 size_t count, loff_t *ppos)
351{
352 char *msg;
353 struct blk_trace *bt;
354
355 if (count >= BLK_TN_MAX_MSG)
356 return -EINVAL;
357
358 msg = memdup_user_nul(buffer, count);
359 if (IS_ERR(msg))
360 return PTR_ERR(msg);
361
362 bt = filp->private_data;
363 __trace_note_message(bt, "%s", msg);
364 kfree(msg);
365
366 return count;
367}
368
369static const struct file_operations blk_msg_fops = {
370 .owner = THIS_MODULE,
371 .open = simple_open,
372 .write = blk_msg_write,
373 .llseek = noop_llseek,
374};
375
376/*
377 * Keep track of how many times we encountered a full subbuffer, to aid
378 * the user space app in telling how many lost events there were.
379 */
380static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
381 void *prev_subbuf, size_t prev_padding)
382{
383 struct blk_trace *bt;
384
385 if (!relay_buf_full(buf))
386 return 1;
387
388 bt = buf->chan->private_data;
389 atomic_inc(&bt->dropped);
390 return 0;
391}
392
393static int blk_remove_buf_file_callback(struct dentry *dentry)
394{
395 debugfs_remove(dentry);
396
397 return 0;
398}
399
400static struct dentry *blk_create_buf_file_callback(const char *filename,
401 struct dentry *parent,
402 umode_t mode,
403 struct rchan_buf *buf,
404 int *is_global)
405{
406 return debugfs_create_file(filename, mode, parent, buf,
407 &relay_file_operations);
408}
409
410static struct rchan_callbacks blk_relay_callbacks = {
411 .subbuf_start = blk_subbuf_start_callback,
412 .create_buf_file = blk_create_buf_file_callback,
413 .remove_buf_file = blk_remove_buf_file_callback,
414};
415
416static void blk_trace_setup_lba(struct blk_trace *bt,
417 struct block_device *bdev)
418{
419 struct hd_struct *part = NULL;
420
421 if (bdev)
422 part = bdev->bd_part;
423
424 if (part) {
425 bt->start_lba = part->start_sect;
426 bt->end_lba = part->start_sect + part->nr_sects;
427 } else {
428 bt->start_lba = 0;
429 bt->end_lba = -1ULL;
430 }
431}
432
433/*
434 * Setup everything required to start tracing
435 */
436int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
437 struct block_device *bdev,
438 struct blk_user_trace_setup *buts)
439{
440 struct blk_trace *bt = NULL;
441 struct dentry *dir = NULL;
442 int ret;
443
444 if (!buts->buf_size || !buts->buf_nr)
445 return -EINVAL;
446
447 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
448 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
449
450 /*
451 * some device names have larger paths - convert the slashes
452 * to underscores for this to work as expected
453 */
454 strreplace(buts->name, '/', '_');
455
456 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
457 if (!bt)
458 return -ENOMEM;
459
460 ret = -ENOMEM;
461 bt->sequence = alloc_percpu(unsigned long);
462 if (!bt->sequence)
463 goto err;
464
465 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
466 if (!bt->msg_data)
467 goto err;
468
469 ret = -ENOENT;
470
471 mutex_lock(&blk_tree_mutex);
472 if (!blk_tree_root) {
473 blk_tree_root = debugfs_create_dir("block", NULL);
474 if (!blk_tree_root) {
475 mutex_unlock(&blk_tree_mutex);
476 goto err;
477 }
478 }
479 mutex_unlock(&blk_tree_mutex);
480
481 dir = debugfs_create_dir(buts->name, blk_tree_root);
482
483 if (!dir)
484 goto err;
485
486 bt->dir = dir;
487 bt->dev = dev;
488 atomic_set(&bt->dropped, 0);
489 INIT_LIST_HEAD(&bt->running_list);
490
491 ret = -EIO;
492 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
493 &blk_dropped_fops);
494 if (!bt->dropped_file)
495 goto err;
496
497 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
498 if (!bt->msg_file)
499 goto err;
500
501 bt->rchan = relay_open("trace", dir, buts->buf_size,
502 buts->buf_nr, &blk_relay_callbacks, bt);
503 if (!bt->rchan)
504 goto err;
505
506 bt->act_mask = buts->act_mask;
507 if (!bt->act_mask)
508 bt->act_mask = (u16) -1;
509
510 blk_trace_setup_lba(bt, bdev);
511
512 /* overwrite with user settings */
513 if (buts->start_lba)
514 bt->start_lba = buts->start_lba;
515 if (buts->end_lba)
516 bt->end_lba = buts->end_lba;
517
518 bt->pid = buts->pid;
519 bt->trace_state = Blktrace_setup;
520
521 ret = -EBUSY;
522 if (cmpxchg(&q->blk_trace, NULL, bt))
523 goto err;
524
525 if (atomic_inc_return(&blk_probes_ref) == 1)
526 blk_register_tracepoints();
527
528 return 0;
529err:
530 blk_trace_free(bt);
531 return ret;
532}
533
534int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
535 struct block_device *bdev,
536 char __user *arg)
537{
538 struct blk_user_trace_setup buts;
539 int ret;
540
541 ret = copy_from_user(&buts, arg, sizeof(buts));
542 if (ret)
543 return -EFAULT;
544
545 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
546 if (ret)
547 return ret;
548
549 if (copy_to_user(arg, &buts, sizeof(buts))) {
550 blk_trace_remove(q);
551 return -EFAULT;
552 }
553 return 0;
554}
555EXPORT_SYMBOL_GPL(blk_trace_setup);
556
557#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
558static int compat_blk_trace_setup(struct request_queue *q, char *name,
559 dev_t dev, struct block_device *bdev,
560 char __user *arg)
561{
562 struct blk_user_trace_setup buts;
563 struct compat_blk_user_trace_setup cbuts;
564 int ret;
565
566 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
567 return -EFAULT;
568
569 buts = (struct blk_user_trace_setup) {
570 .act_mask = cbuts.act_mask,
571 .buf_size = cbuts.buf_size,
572 .buf_nr = cbuts.buf_nr,
573 .start_lba = cbuts.start_lba,
574 .end_lba = cbuts.end_lba,
575 .pid = cbuts.pid,
576 };
577
578 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
579 if (ret)
580 return ret;
581
582 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
583 blk_trace_remove(q);
584 return -EFAULT;
585 }
586
587 return 0;
588}
589#endif
590
591int blk_trace_startstop(struct request_queue *q, int start)
592{
593 int ret;
594 struct blk_trace *bt = q->blk_trace;
595
596 if (bt == NULL)
597 return -EINVAL;
598
599 /*
600 * For starting a trace, we can transition from a setup or stopped
601 * trace. For stopping a trace, the state must be running
602 */
603 ret = -EINVAL;
604 if (start) {
605 if (bt->trace_state == Blktrace_setup ||
606 bt->trace_state == Blktrace_stopped) {
607 blktrace_seq++;
608 smp_mb();
609 bt->trace_state = Blktrace_running;
610 spin_lock_irq(&running_trace_lock);
611 list_add(&bt->running_list, &running_trace_list);
612 spin_unlock_irq(&running_trace_lock);
613
614 trace_note_time(bt);
615 ret = 0;
616 }
617 } else {
618 if (bt->trace_state == Blktrace_running) {
619 bt->trace_state = Blktrace_stopped;
620 spin_lock_irq(&running_trace_lock);
621 list_del_init(&bt->running_list);
622 spin_unlock_irq(&running_trace_lock);
623 relay_flush(bt->rchan);
624 ret = 0;
625 }
626 }
627
628 return ret;
629}
630EXPORT_SYMBOL_GPL(blk_trace_startstop);
631
632/**
633 * blk_trace_ioctl: - handle the ioctls associated with tracing
634 * @bdev: the block device
635 * @cmd: the ioctl cmd
636 * @arg: the argument data, if any
637 *
638 **/
639int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
640{
641 struct request_queue *q;
642 int ret, start = 0;
643 char b[BDEVNAME_SIZE];
644
645 q = bdev_get_queue(bdev);
646 if (!q)
647 return -ENXIO;
648
649 mutex_lock(&bdev->bd_mutex);
650
651 switch (cmd) {
652 case BLKTRACESETUP:
653 bdevname(bdev, b);
654 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
655 break;
656#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
657 case BLKTRACESETUP32:
658 bdevname(bdev, b);
659 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
660 break;
661#endif
662 case BLKTRACESTART:
663 start = 1;
664 case BLKTRACESTOP:
665 ret = blk_trace_startstop(q, start);
666 break;
667 case BLKTRACETEARDOWN:
668 ret = blk_trace_remove(q);
669 break;
670 default:
671 ret = -ENOTTY;
672 break;
673 }
674
675 mutex_unlock(&bdev->bd_mutex);
676 return ret;
677}
678
679/**
680 * blk_trace_shutdown: - stop and cleanup trace structures
681 * @q: the request queue associated with the device
682 *
683 **/
684void blk_trace_shutdown(struct request_queue *q)
685{
686 if (q->blk_trace) {
687 blk_trace_startstop(q, 0);
688 blk_trace_remove(q);
689 }
690}
691
692/*
693 * blktrace probes
694 */
695
696/**
697 * blk_add_trace_rq - Add a trace for a request oriented action
698 * @q: queue the io is for
699 * @rq: the source request
700 * @nr_bytes: number of completed bytes
701 * @what: the action
702 *
703 * Description:
704 * Records an action against a request. Will log the bio offset + size.
705 *
706 **/
707static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
708 unsigned int nr_bytes, u32 what)
709{
710 struct blk_trace *bt = q->blk_trace;
711
712 if (likely(!bt))
713 return;
714
715 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
716 what |= BLK_TC_ACT(BLK_TC_PC);
717 __blk_add_trace(bt, 0, nr_bytes, req_op(rq), rq->cmd_flags,
718 what, rq->errors, rq->cmd_len, rq->cmd);
719 } else {
720 what |= BLK_TC_ACT(BLK_TC_FS);
721 __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes, req_op(rq),
722 rq->cmd_flags, what, rq->errors, 0, NULL);
723 }
724}
725
726static void blk_add_trace_rq_abort(void *ignore,
727 struct request_queue *q, struct request *rq)
728{
729 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT);
730}
731
732static void blk_add_trace_rq_insert(void *ignore,
733 struct request_queue *q, struct request *rq)
734{
735 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT);
736}
737
738static void blk_add_trace_rq_issue(void *ignore,
739 struct request_queue *q, struct request *rq)
740{
741 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE);
742}
743
744static void blk_add_trace_rq_requeue(void *ignore,
745 struct request_queue *q,
746 struct request *rq)
747{
748 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE);
749}
750
751static void blk_add_trace_rq_complete(void *ignore,
752 struct request_queue *q,
753 struct request *rq,
754 unsigned int nr_bytes)
755{
756 blk_add_trace_rq(q, rq, nr_bytes, BLK_TA_COMPLETE);
757}
758
759/**
760 * blk_add_trace_bio - Add a trace for a bio oriented action
761 * @q: queue the io is for
762 * @bio: the source bio
763 * @what: the action
764 * @error: error, if any
765 *
766 * Description:
767 * Records an action against a bio. Will log the bio offset + size.
768 *
769 **/
770static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
771 u32 what, int error)
772{
773 struct blk_trace *bt = q->blk_trace;
774
775 if (likely(!bt))
776 return;
777
778 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
779 bio_op(bio), bio->bi_opf, what, error, 0, NULL);
780}
781
782static void blk_add_trace_bio_bounce(void *ignore,
783 struct request_queue *q, struct bio *bio)
784{
785 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
786}
787
788static void blk_add_trace_bio_complete(void *ignore,
789 struct request_queue *q, struct bio *bio,
790 int error)
791{
792 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
793}
794
795static void blk_add_trace_bio_backmerge(void *ignore,
796 struct request_queue *q,
797 struct request *rq,
798 struct bio *bio)
799{
800 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
801}
802
803static void blk_add_trace_bio_frontmerge(void *ignore,
804 struct request_queue *q,
805 struct request *rq,
806 struct bio *bio)
807{
808 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
809}
810
811static void blk_add_trace_bio_queue(void *ignore,
812 struct request_queue *q, struct bio *bio)
813{
814 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
815}
816
817static void blk_add_trace_getrq(void *ignore,
818 struct request_queue *q,
819 struct bio *bio, int rw)
820{
821 if (bio)
822 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
823 else {
824 struct blk_trace *bt = q->blk_trace;
825
826 if (bt)
827 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
828 NULL);
829 }
830}
831
832
833static void blk_add_trace_sleeprq(void *ignore,
834 struct request_queue *q,
835 struct bio *bio, int rw)
836{
837 if (bio)
838 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
839 else {
840 struct blk_trace *bt = q->blk_trace;
841
842 if (bt)
843 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
844 0, 0, NULL);
845 }
846}
847
848static void blk_add_trace_plug(void *ignore, struct request_queue *q)
849{
850 struct blk_trace *bt = q->blk_trace;
851
852 if (bt)
853 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
854}
855
856static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
857 unsigned int depth, bool explicit)
858{
859 struct blk_trace *bt = q->blk_trace;
860
861 if (bt) {
862 __be64 rpdu = cpu_to_be64(depth);
863 u32 what;
864
865 if (explicit)
866 what = BLK_TA_UNPLUG_IO;
867 else
868 what = BLK_TA_UNPLUG_TIMER;
869
870 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
871 }
872}
873
874static void blk_add_trace_split(void *ignore,
875 struct request_queue *q, struct bio *bio,
876 unsigned int pdu)
877{
878 struct blk_trace *bt = q->blk_trace;
879
880 if (bt) {
881 __be64 rpdu = cpu_to_be64(pdu);
882
883 __blk_add_trace(bt, bio->bi_iter.bi_sector,
884 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
885 BLK_TA_SPLIT, bio->bi_error, sizeof(rpdu),
886 &rpdu);
887 }
888}
889
890/**
891 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
892 * @ignore: trace callback data parameter (not used)
893 * @q: queue the io is for
894 * @bio: the source bio
895 * @dev: target device
896 * @from: source sector
897 *
898 * Description:
899 * Device mapper or raid target sometimes need to split a bio because
900 * it spans a stripe (or similar). Add a trace for that action.
901 *
902 **/
903static void blk_add_trace_bio_remap(void *ignore,
904 struct request_queue *q, struct bio *bio,
905 dev_t dev, sector_t from)
906{
907 struct blk_trace *bt = q->blk_trace;
908 struct blk_io_trace_remap r;
909
910 if (likely(!bt))
911 return;
912
913 r.device_from = cpu_to_be32(dev);
914 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
915 r.sector_from = cpu_to_be64(from);
916
917 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
918 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_error,
919 sizeof(r), &r);
920}
921
922/**
923 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
924 * @ignore: trace callback data parameter (not used)
925 * @q: queue the io is for
926 * @rq: the source request
927 * @dev: target device
928 * @from: source sector
929 *
930 * Description:
931 * Device mapper remaps request to other devices.
932 * Add a trace for that action.
933 *
934 **/
935static void blk_add_trace_rq_remap(void *ignore,
936 struct request_queue *q,
937 struct request *rq, dev_t dev,
938 sector_t from)
939{
940 struct blk_trace *bt = q->blk_trace;
941 struct blk_io_trace_remap r;
942
943 if (likely(!bt))
944 return;
945
946 r.device_from = cpu_to_be32(dev);
947 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
948 r.sector_from = cpu_to_be64(from);
949
950 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
951 rq_data_dir(rq), 0, BLK_TA_REMAP, !!rq->errors,
952 sizeof(r), &r);
953}
954
955/**
956 * blk_add_driver_data - Add binary message with driver-specific data
957 * @q: queue the io is for
958 * @rq: io request
959 * @data: driver-specific data
960 * @len: length of driver-specific data
961 *
962 * Description:
963 * Some drivers might want to write driver-specific data per request.
964 *
965 **/
966void blk_add_driver_data(struct request_queue *q,
967 struct request *rq,
968 void *data, size_t len)
969{
970 struct blk_trace *bt = q->blk_trace;
971
972 if (likely(!bt))
973 return;
974
975 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
976 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0, 0,
977 BLK_TA_DRV_DATA, rq->errors, len, data);
978 else
979 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0, 0,
980 BLK_TA_DRV_DATA, rq->errors, len, data);
981}
982EXPORT_SYMBOL_GPL(blk_add_driver_data);
983
984static void blk_register_tracepoints(void)
985{
986 int ret;
987
988 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
989 WARN_ON(ret);
990 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
991 WARN_ON(ret);
992 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
993 WARN_ON(ret);
994 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
995 WARN_ON(ret);
996 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
997 WARN_ON(ret);
998 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
999 WARN_ON(ret);
1000 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1001 WARN_ON(ret);
1002 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1003 WARN_ON(ret);
1004 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1005 WARN_ON(ret);
1006 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1007 WARN_ON(ret);
1008 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1009 WARN_ON(ret);
1010 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1011 WARN_ON(ret);
1012 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1013 WARN_ON(ret);
1014 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1015 WARN_ON(ret);
1016 ret = register_trace_block_split(blk_add_trace_split, NULL);
1017 WARN_ON(ret);
1018 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1019 WARN_ON(ret);
1020 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1021 WARN_ON(ret);
1022}
1023
1024static void blk_unregister_tracepoints(void)
1025{
1026 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1027 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1028 unregister_trace_block_split(blk_add_trace_split, NULL);
1029 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1030 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1031 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1032 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1033 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1034 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1035 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1036 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1037 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1038 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1039 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1040 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1041 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1042 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1043
1044 tracepoint_synchronize_unregister();
1045}
1046
1047/*
1048 * struct blk_io_tracer formatting routines
1049 */
1050
1051static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1052{
1053 int i = 0;
1054 int tc = t->action >> BLK_TC_SHIFT;
1055
1056 if (t->action == BLK_TN_MESSAGE) {
1057 rwbs[i++] = 'N';
1058 goto out;
1059 }
1060
1061 if (tc & BLK_TC_FLUSH)
1062 rwbs[i++] = 'F';
1063
1064 if (tc & BLK_TC_DISCARD)
1065 rwbs[i++] = 'D';
1066 else if (tc & BLK_TC_WRITE)
1067 rwbs[i++] = 'W';
1068 else if (t->bytes)
1069 rwbs[i++] = 'R';
1070 else
1071 rwbs[i++] = 'N';
1072
1073 if (tc & BLK_TC_FUA)
1074 rwbs[i++] = 'F';
1075 if (tc & BLK_TC_AHEAD)
1076 rwbs[i++] = 'A';
1077 if (tc & BLK_TC_SYNC)
1078 rwbs[i++] = 'S';
1079 if (tc & BLK_TC_META)
1080 rwbs[i++] = 'M';
1081out:
1082 rwbs[i] = '\0';
1083}
1084
1085static inline
1086const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1087{
1088 return (const struct blk_io_trace *)ent;
1089}
1090
1091static inline const void *pdu_start(const struct trace_entry *ent)
1092{
1093 return te_blk_io_trace(ent) + 1;
1094}
1095
1096static inline u32 t_action(const struct trace_entry *ent)
1097{
1098 return te_blk_io_trace(ent)->action;
1099}
1100
1101static inline u32 t_bytes(const struct trace_entry *ent)
1102{
1103 return te_blk_io_trace(ent)->bytes;
1104}
1105
1106static inline u32 t_sec(const struct trace_entry *ent)
1107{
1108 return te_blk_io_trace(ent)->bytes >> 9;
1109}
1110
1111static inline unsigned long long t_sector(const struct trace_entry *ent)
1112{
1113 return te_blk_io_trace(ent)->sector;
1114}
1115
1116static inline __u16 t_error(const struct trace_entry *ent)
1117{
1118 return te_blk_io_trace(ent)->error;
1119}
1120
1121static __u64 get_pdu_int(const struct trace_entry *ent)
1122{
1123 const __u64 *val = pdu_start(ent);
1124 return be64_to_cpu(*val);
1125}
1126
1127static void get_pdu_remap(const struct trace_entry *ent,
1128 struct blk_io_trace_remap *r)
1129{
1130 const struct blk_io_trace_remap *__r = pdu_start(ent);
1131 __u64 sector_from = __r->sector_from;
1132
1133 r->device_from = be32_to_cpu(__r->device_from);
1134 r->device_to = be32_to_cpu(__r->device_to);
1135 r->sector_from = be64_to_cpu(sector_from);
1136}
1137
1138typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1139
1140static void blk_log_action_classic(struct trace_iterator *iter, const char *act)
1141{
1142 char rwbs[RWBS_LEN];
1143 unsigned long long ts = iter->ts;
1144 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1145 unsigned secs = (unsigned long)ts;
1146 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1147
1148 fill_rwbs(rwbs, t);
1149
1150 trace_seq_printf(&iter->seq,
1151 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1152 MAJOR(t->device), MINOR(t->device), iter->cpu,
1153 secs, nsec_rem, iter->ent->pid, act, rwbs);
1154}
1155
1156static void blk_log_action(struct trace_iterator *iter, const char *act)
1157{
1158 char rwbs[RWBS_LEN];
1159 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1160
1161 fill_rwbs(rwbs, t);
1162 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1163 MAJOR(t->device), MINOR(t->device), act, rwbs);
1164}
1165
1166static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1167{
1168 const unsigned char *pdu_buf;
1169 int pdu_len;
1170 int i, end;
1171
1172 pdu_buf = pdu_start(ent);
1173 pdu_len = te_blk_io_trace(ent)->pdu_len;
1174
1175 if (!pdu_len)
1176 return;
1177
1178 /* find the last zero that needs to be printed */
1179 for (end = pdu_len - 1; end >= 0; end--)
1180 if (pdu_buf[end])
1181 break;
1182 end++;
1183
1184 trace_seq_putc(s, '(');
1185
1186 for (i = 0; i < pdu_len; i++) {
1187
1188 trace_seq_printf(s, "%s%02x",
1189 i == 0 ? "" : " ", pdu_buf[i]);
1190
1191 /*
1192 * stop when the rest is just zeroes and indicate so
1193 * with a ".." appended
1194 */
1195 if (i == end && end != pdu_len - 1) {
1196 trace_seq_puts(s, " ..) ");
1197 return;
1198 }
1199 }
1200
1201 trace_seq_puts(s, ") ");
1202}
1203
1204static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1205{
1206 char cmd[TASK_COMM_LEN];
1207
1208 trace_find_cmdline(ent->pid, cmd);
1209
1210 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1211 trace_seq_printf(s, "%u ", t_bytes(ent));
1212 blk_log_dump_pdu(s, ent);
1213 trace_seq_printf(s, "[%s]\n", cmd);
1214 } else {
1215 if (t_sec(ent))
1216 trace_seq_printf(s, "%llu + %u [%s]\n",
1217 t_sector(ent), t_sec(ent), cmd);
1218 else
1219 trace_seq_printf(s, "[%s]\n", cmd);
1220 }
1221}
1222
1223static void blk_log_with_error(struct trace_seq *s,
1224 const struct trace_entry *ent)
1225{
1226 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1227 blk_log_dump_pdu(s, ent);
1228 trace_seq_printf(s, "[%d]\n", t_error(ent));
1229 } else {
1230 if (t_sec(ent))
1231 trace_seq_printf(s, "%llu + %u [%d]\n",
1232 t_sector(ent),
1233 t_sec(ent), t_error(ent));
1234 else
1235 trace_seq_printf(s, "%llu [%d]\n",
1236 t_sector(ent), t_error(ent));
1237 }
1238}
1239
1240static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1241{
1242 struct blk_io_trace_remap r = { .device_from = 0, };
1243
1244 get_pdu_remap(ent, &r);
1245 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1246 t_sector(ent), t_sec(ent),
1247 MAJOR(r.device_from), MINOR(r.device_from),
1248 (unsigned long long)r.sector_from);
1249}
1250
1251static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1252{
1253 char cmd[TASK_COMM_LEN];
1254
1255 trace_find_cmdline(ent->pid, cmd);
1256
1257 trace_seq_printf(s, "[%s]\n", cmd);
1258}
1259
1260static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1261{
1262 char cmd[TASK_COMM_LEN];
1263
1264 trace_find_cmdline(ent->pid, cmd);
1265
1266 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1267}
1268
1269static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1270{
1271 char cmd[TASK_COMM_LEN];
1272
1273 trace_find_cmdline(ent->pid, cmd);
1274
1275 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1276 get_pdu_int(ent), cmd);
1277}
1278
1279static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1280{
1281 const struct blk_io_trace *t = te_blk_io_trace(ent);
1282
1283 trace_seq_putmem(s, t + 1, t->pdu_len);
1284 trace_seq_putc(s, '\n');
1285}
1286
1287/*
1288 * struct tracer operations
1289 */
1290
1291static void blk_tracer_print_header(struct seq_file *m)
1292{
1293 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1294 return;
1295 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1296 "# | | | | | |\n");
1297}
1298
1299static void blk_tracer_start(struct trace_array *tr)
1300{
1301 blk_tracer_enabled = true;
1302}
1303
1304static int blk_tracer_init(struct trace_array *tr)
1305{
1306 blk_tr = tr;
1307 blk_tracer_start(tr);
1308 return 0;
1309}
1310
1311static void blk_tracer_stop(struct trace_array *tr)
1312{
1313 blk_tracer_enabled = false;
1314}
1315
1316static void blk_tracer_reset(struct trace_array *tr)
1317{
1318 blk_tracer_stop(tr);
1319}
1320
1321static const struct {
1322 const char *act[2];
1323 void (*print)(struct trace_seq *s, const struct trace_entry *ent);
1324} what2act[] = {
1325 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1326 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1327 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1328 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1329 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1330 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1331 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1332 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1333 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1334 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1335 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1336 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1337 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1338 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1339 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1340};
1341
1342static enum print_line_t print_one_line(struct trace_iterator *iter,
1343 bool classic)
1344{
1345 struct trace_array *tr = iter->tr;
1346 struct trace_seq *s = &iter->seq;
1347 const struct blk_io_trace *t;
1348 u16 what;
1349 bool long_act;
1350 blk_log_action_t *log_action;
1351
1352 t = te_blk_io_trace(iter->ent);
1353 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1354 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1355 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1356
1357 if (t->action == BLK_TN_MESSAGE) {
1358 log_action(iter, long_act ? "message" : "m");
1359 blk_log_msg(s, iter->ent);
1360 return trace_handle_return(s);
1361 }
1362
1363 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1364 trace_seq_printf(s, "Unknown action %x\n", what);
1365 else {
1366 log_action(iter, what2act[what].act[long_act]);
1367 what2act[what].print(s, iter->ent);
1368 }
1369
1370 return trace_handle_return(s);
1371}
1372
1373static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1374 int flags, struct trace_event *event)
1375{
1376 return print_one_line(iter, false);
1377}
1378
1379static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1380{
1381 struct trace_seq *s = &iter->seq;
1382 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1383 const int offset = offsetof(struct blk_io_trace, sector);
1384 struct blk_io_trace old = {
1385 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1386 .time = iter->ts,
1387 };
1388
1389 trace_seq_putmem(s, &old, offset);
1390 trace_seq_putmem(s, &t->sector,
1391 sizeof(old) - offset + t->pdu_len);
1392}
1393
1394static enum print_line_t
1395blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1396 struct trace_event *event)
1397{
1398 blk_trace_synthesize_old_trace(iter);
1399
1400 return trace_handle_return(&iter->seq);
1401}
1402
1403static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1404{
1405 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1406 return TRACE_TYPE_UNHANDLED;
1407
1408 return print_one_line(iter, true);
1409}
1410
1411static int
1412blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1413{
1414 /* don't output context-info for blk_classic output */
1415 if (bit == TRACE_BLK_OPT_CLASSIC) {
1416 if (set)
1417 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1418 else
1419 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1420 }
1421 return 0;
1422}
1423
1424static struct tracer blk_tracer __read_mostly = {
1425 .name = "blk",
1426 .init = blk_tracer_init,
1427 .reset = blk_tracer_reset,
1428 .start = blk_tracer_start,
1429 .stop = blk_tracer_stop,
1430 .print_header = blk_tracer_print_header,
1431 .print_line = blk_tracer_print_line,
1432 .flags = &blk_tracer_flags,
1433 .set_flag = blk_tracer_set_flag,
1434};
1435
1436static struct trace_event_functions trace_blk_event_funcs = {
1437 .trace = blk_trace_event_print,
1438 .binary = blk_trace_event_print_binary,
1439};
1440
1441static struct trace_event trace_blk_event = {
1442 .type = TRACE_BLK,
1443 .funcs = &trace_blk_event_funcs,
1444};
1445
1446static int __init init_blk_tracer(void)
1447{
1448 if (!register_trace_event(&trace_blk_event)) {
1449 pr_warn("Warning: could not register block events\n");
1450 return 1;
1451 }
1452
1453 if (register_tracer(&blk_tracer) != 0) {
1454 pr_warn("Warning: could not register the block tracer\n");
1455 unregister_trace_event(&trace_blk_event);
1456 return 1;
1457 }
1458
1459 return 0;
1460}
1461
1462device_initcall(init_blk_tracer);
1463
1464static int blk_trace_remove_queue(struct request_queue *q)
1465{
1466 struct blk_trace *bt;
1467
1468 bt = xchg(&q->blk_trace, NULL);
1469 if (bt == NULL)
1470 return -EINVAL;
1471
1472 if (atomic_dec_and_test(&blk_probes_ref))
1473 blk_unregister_tracepoints();
1474
1475 blk_trace_free(bt);
1476 return 0;
1477}
1478
1479/*
1480 * Setup everything required to start tracing
1481 */
1482static int blk_trace_setup_queue(struct request_queue *q,
1483 struct block_device *bdev)
1484{
1485 struct blk_trace *bt = NULL;
1486 int ret = -ENOMEM;
1487
1488 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1489 if (!bt)
1490 return -ENOMEM;
1491
1492 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1493 if (!bt->msg_data)
1494 goto free_bt;
1495
1496 bt->dev = bdev->bd_dev;
1497 bt->act_mask = (u16)-1;
1498
1499 blk_trace_setup_lba(bt, bdev);
1500
1501 ret = -EBUSY;
1502 if (cmpxchg(&q->blk_trace, NULL, bt))
1503 goto free_bt;
1504
1505 if (atomic_inc_return(&blk_probes_ref) == 1)
1506 blk_register_tracepoints();
1507 return 0;
1508
1509free_bt:
1510 blk_trace_free(bt);
1511 return ret;
1512}
1513
1514/*
1515 * sysfs interface to enable and configure tracing
1516 */
1517
1518static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1519 struct device_attribute *attr,
1520 char *buf);
1521static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1522 struct device_attribute *attr,
1523 const char *buf, size_t count);
1524#define BLK_TRACE_DEVICE_ATTR(_name) \
1525 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1526 sysfs_blk_trace_attr_show, \
1527 sysfs_blk_trace_attr_store)
1528
1529static BLK_TRACE_DEVICE_ATTR(enable);
1530static BLK_TRACE_DEVICE_ATTR(act_mask);
1531static BLK_TRACE_DEVICE_ATTR(pid);
1532static BLK_TRACE_DEVICE_ATTR(start_lba);
1533static BLK_TRACE_DEVICE_ATTR(end_lba);
1534
1535static struct attribute *blk_trace_attrs[] = {
1536 &dev_attr_enable.attr,
1537 &dev_attr_act_mask.attr,
1538 &dev_attr_pid.attr,
1539 &dev_attr_start_lba.attr,
1540 &dev_attr_end_lba.attr,
1541 NULL
1542};
1543
1544struct attribute_group blk_trace_attr_group = {
1545 .name = "trace",
1546 .attrs = blk_trace_attrs,
1547};
1548
1549static const struct {
1550 int mask;
1551 const char *str;
1552} mask_maps[] = {
1553 { BLK_TC_READ, "read" },
1554 { BLK_TC_WRITE, "write" },
1555 { BLK_TC_FLUSH, "flush" },
1556 { BLK_TC_SYNC, "sync" },
1557 { BLK_TC_QUEUE, "queue" },
1558 { BLK_TC_REQUEUE, "requeue" },
1559 { BLK_TC_ISSUE, "issue" },
1560 { BLK_TC_COMPLETE, "complete" },
1561 { BLK_TC_FS, "fs" },
1562 { BLK_TC_PC, "pc" },
1563 { BLK_TC_NOTIFY, "notify" },
1564 { BLK_TC_AHEAD, "ahead" },
1565 { BLK_TC_META, "meta" },
1566 { BLK_TC_DISCARD, "discard" },
1567 { BLK_TC_DRV_DATA, "drv_data" },
1568 { BLK_TC_FUA, "fua" },
1569};
1570
1571static int blk_trace_str2mask(const char *str)
1572{
1573 int i;
1574 int mask = 0;
1575 char *buf, *s, *token;
1576
1577 buf = kstrdup(str, GFP_KERNEL);
1578 if (buf == NULL)
1579 return -ENOMEM;
1580 s = strstrip(buf);
1581
1582 while (1) {
1583 token = strsep(&s, ",");
1584 if (token == NULL)
1585 break;
1586
1587 if (*token == '\0')
1588 continue;
1589
1590 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1591 if (strcasecmp(token, mask_maps[i].str) == 0) {
1592 mask |= mask_maps[i].mask;
1593 break;
1594 }
1595 }
1596 if (i == ARRAY_SIZE(mask_maps)) {
1597 mask = -EINVAL;
1598 break;
1599 }
1600 }
1601 kfree(buf);
1602
1603 return mask;
1604}
1605
1606static ssize_t blk_trace_mask2str(char *buf, int mask)
1607{
1608 int i;
1609 char *p = buf;
1610
1611 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1612 if (mask & mask_maps[i].mask) {
1613 p += sprintf(p, "%s%s",
1614 (p == buf) ? "" : ",", mask_maps[i].str);
1615 }
1616 }
1617 *p++ = '\n';
1618
1619 return p - buf;
1620}
1621
1622static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1623{
1624 if (bdev->bd_disk == NULL)
1625 return NULL;
1626
1627 return bdev_get_queue(bdev);
1628}
1629
1630static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1631 struct device_attribute *attr,
1632 char *buf)
1633{
1634 struct hd_struct *p = dev_to_part(dev);
1635 struct request_queue *q;
1636 struct block_device *bdev;
1637 ssize_t ret = -ENXIO;
1638
1639 bdev = bdget(part_devt(p));
1640 if (bdev == NULL)
1641 goto out;
1642
1643 q = blk_trace_get_queue(bdev);
1644 if (q == NULL)
1645 goto out_bdput;
1646
1647 mutex_lock(&bdev->bd_mutex);
1648
1649 if (attr == &dev_attr_enable) {
1650 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1651 goto out_unlock_bdev;
1652 }
1653
1654 if (q->blk_trace == NULL)
1655 ret = sprintf(buf, "disabled\n");
1656 else if (attr == &dev_attr_act_mask)
1657 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1658 else if (attr == &dev_attr_pid)
1659 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1660 else if (attr == &dev_attr_start_lba)
1661 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1662 else if (attr == &dev_attr_end_lba)
1663 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1664
1665out_unlock_bdev:
1666 mutex_unlock(&bdev->bd_mutex);
1667out_bdput:
1668 bdput(bdev);
1669out:
1670 return ret;
1671}
1672
1673static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1674 struct device_attribute *attr,
1675 const char *buf, size_t count)
1676{
1677 struct block_device *bdev;
1678 struct request_queue *q;
1679 struct hd_struct *p;
1680 u64 value;
1681 ssize_t ret = -EINVAL;
1682
1683 if (count == 0)
1684 goto out;
1685
1686 if (attr == &dev_attr_act_mask) {
1687 if (sscanf(buf, "%llx", &value) != 1) {
1688 /* Assume it is a list of trace category names */
1689 ret = blk_trace_str2mask(buf);
1690 if (ret < 0)
1691 goto out;
1692 value = ret;
1693 }
1694 } else if (sscanf(buf, "%llu", &value) != 1)
1695 goto out;
1696
1697 ret = -ENXIO;
1698
1699 p = dev_to_part(dev);
1700 bdev = bdget(part_devt(p));
1701 if (bdev == NULL)
1702 goto out;
1703
1704 q = blk_trace_get_queue(bdev);
1705 if (q == NULL)
1706 goto out_bdput;
1707
1708 mutex_lock(&bdev->bd_mutex);
1709
1710 if (attr == &dev_attr_enable) {
1711 if (value)
1712 ret = blk_trace_setup_queue(q, bdev);
1713 else
1714 ret = blk_trace_remove_queue(q);
1715 goto out_unlock_bdev;
1716 }
1717
1718 ret = 0;
1719 if (q->blk_trace == NULL)
1720 ret = blk_trace_setup_queue(q, bdev);
1721
1722 if (ret == 0) {
1723 if (attr == &dev_attr_act_mask)
1724 q->blk_trace->act_mask = value;
1725 else if (attr == &dev_attr_pid)
1726 q->blk_trace->pid = value;
1727 else if (attr == &dev_attr_start_lba)
1728 q->blk_trace->start_lba = value;
1729 else if (attr == &dev_attr_end_lba)
1730 q->blk_trace->end_lba = value;
1731 }
1732
1733out_unlock_bdev:
1734 mutex_unlock(&bdev->bd_mutex);
1735out_bdput:
1736 bdput(bdev);
1737out:
1738 return ret ? ret : count;
1739}
1740
1741int blk_trace_init_sysfs(struct device *dev)
1742{
1743 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1744}
1745
1746void blk_trace_remove_sysfs(struct device *dev)
1747{
1748 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1749}
1750
1751#endif /* CONFIG_BLK_DEV_IO_TRACE */
1752
1753#ifdef CONFIG_EVENT_TRACING
1754
1755void blk_dump_cmd(char *buf, struct request *rq)
1756{
1757 int i, end;
1758 int len = rq->cmd_len;
1759 unsigned char *cmd = rq->cmd;
1760
1761 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1762 buf[0] = '\0';
1763 return;
1764 }
1765
1766 for (end = len - 1; end >= 0; end--)
1767 if (cmd[end])
1768 break;
1769 end++;
1770
1771 for (i = 0; i < len; i++) {
1772 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1773 if (i == end && end != len - 1) {
1774 sprintf(buf, " ..");
1775 break;
1776 }
1777 }
1778}
1779
1780void blk_fill_rwbs(char *rwbs, int op, u32 rw, int bytes)
1781{
1782 int i = 0;
1783
1784 if (rw & REQ_PREFLUSH)
1785 rwbs[i++] = 'F';
1786
1787 switch (op) {
1788 case REQ_OP_WRITE:
1789 case REQ_OP_WRITE_SAME:
1790 rwbs[i++] = 'W';
1791 break;
1792 case REQ_OP_DISCARD:
1793 rwbs[i++] = 'D';
1794 break;
1795 case REQ_OP_SECURE_ERASE:
1796 rwbs[i++] = 'D';
1797 rwbs[i++] = 'E';
1798 break;
1799 case REQ_OP_FLUSH:
1800 rwbs[i++] = 'F';
1801 break;
1802 case REQ_OP_READ:
1803 rwbs[i++] = 'R';
1804 break;
1805 default:
1806 rwbs[i++] = 'N';
1807 }
1808
1809 if (rw & REQ_FUA)
1810 rwbs[i++] = 'F';
1811 if (rw & REQ_RAHEAD)
1812 rwbs[i++] = 'A';
1813 if (rw & REQ_SYNC)
1814 rwbs[i++] = 'S';
1815 if (rw & REQ_META)
1816 rwbs[i++] = 'M';
1817
1818 rwbs[i] = '\0';
1819}
1820EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1821
1822#endif /* CONFIG_EVENT_TRACING */
1823