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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
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(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 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
143void __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}
170EXPORT_SYMBOL_GPL(__trace_note_message);
171
172static 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 */
188static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
189 BLK_TC_ACT(BLK_TC_WRITE) };
190
191#define BLK_TC_RAHEAD BLK_TC_AHEAD
192
193/* The ilog2() calls fall out because they're constant */
194#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
195 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
196
197/*
198 * The worker for the various blk_add_trace*() types. Fills out a
199 * blk_io_trace structure and places it in a per-cpu subbuffer.
200 */
201static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
202 int rw, u32 what, int error, int pdu_len, void *pdu_data)
203{
204 struct task_struct *tsk = current;
205 struct ring_buffer_event *event = NULL;
206 struct ring_buffer *buffer = NULL;
207 struct blk_io_trace *t;
208 unsigned long flags = 0;
209 unsigned long *sequence;
210 pid_t pid;
211 int cpu, pc = 0;
212 bool blk_tracer = blk_tracer_enabled;
213
214 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
215 return;
216
217 what |= ddir_act[rw & WRITE];
218 what |= MASK_TC_BIT(rw, SYNC);
219 what |= MASK_TC_BIT(rw, RAHEAD);
220 what |= MASK_TC_BIT(rw, META);
221 what |= MASK_TC_BIT(rw, DISCARD);
222 what |= MASK_TC_BIT(rw, FLUSH);
223 what |= MASK_TC_BIT(rw, FUA);
224
225 pid = tsk->pid;
226 if (act_log_check(bt, what, sector, pid))
227 return;
228 cpu = raw_smp_processor_id();
229
230 if (blk_tracer) {
231 tracing_record_cmdline(current);
232
233 buffer = blk_tr->trace_buffer.buffer;
234 pc = preempt_count();
235 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
236 sizeof(*t) + pdu_len,
237 0, pc);
238 if (!event)
239 return;
240 t = ring_buffer_event_data(event);
241 goto record_it;
242 }
243
244 if (unlikely(tsk->btrace_seq != blktrace_seq))
245 trace_note_tsk(tsk);
246
247 /*
248 * A word about the locking here - we disable interrupts to reserve
249 * some space in the relay per-cpu buffer, to prevent an irq
250 * from coming in and stepping on our toes.
251 */
252 local_irq_save(flags);
253 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
254 if (t) {
255 sequence = per_cpu_ptr(bt->sequence, cpu);
256
257 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
258 t->sequence = ++(*sequence);
259 t->time = ktime_to_ns(ktime_get());
260record_it:
261 /*
262 * These two are not needed in ftrace as they are in the
263 * generic trace_entry, filled by tracing_generic_entry_update,
264 * but for the trace_event->bin() synthesizer benefit we do it
265 * here too.
266 */
267 t->cpu = cpu;
268 t->pid = pid;
269
270 t->sector = sector;
271 t->bytes = bytes;
272 t->action = what;
273 t->device = bt->dev;
274 t->error = error;
275 t->pdu_len = pdu_len;
276
277 if (pdu_len)
278 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
279
280 if (blk_tracer) {
281 trace_buffer_unlock_commit(buffer, event, 0, pc);
282 return;
283 }
284 }
285
286 local_irq_restore(flags);
287}
288
289static struct dentry *blk_tree_root;
290static DEFINE_MUTEX(blk_tree_mutex);
291
292static void blk_trace_free(struct blk_trace *bt)
293{
294 debugfs_remove(bt->msg_file);
295 debugfs_remove(bt->dropped_file);
296 relay_close(bt->rchan);
297 debugfs_remove(bt->dir);
298 free_percpu(bt->sequence);
299 free_percpu(bt->msg_data);
300 kfree(bt);
301}
302
303static void blk_trace_cleanup(struct blk_trace *bt)
304{
305 blk_trace_free(bt);
306 if (atomic_dec_and_test(&blk_probes_ref))
307 blk_unregister_tracepoints();
308}
309
310int blk_trace_remove(struct request_queue *q)
311{
312 struct blk_trace *bt;
313
314 bt = xchg(&q->blk_trace, NULL);
315 if (!bt)
316 return -EINVAL;
317
318 if (bt->trace_state != Blktrace_running)
319 blk_trace_cleanup(bt);
320
321 return 0;
322}
323EXPORT_SYMBOL_GPL(blk_trace_remove);
324
325static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
326 size_t count, loff_t *ppos)
327{
328 struct blk_trace *bt = filp->private_data;
329 char buf[16];
330
331 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
332
333 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
334}
335
336static const struct file_operations blk_dropped_fops = {
337 .owner = THIS_MODULE,
338 .open = simple_open,
339 .read = blk_dropped_read,
340 .llseek = default_llseek,
341};
342
343static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
344 size_t count, loff_t *ppos)
345{
346 char *msg;
347 struct blk_trace *bt;
348
349 if (count >= BLK_TN_MAX_MSG)
350 return -EINVAL;
351
352 msg = kmalloc(count + 1, GFP_KERNEL);
353 if (msg == NULL)
354 return -ENOMEM;
355
356 if (copy_from_user(msg, buffer, count)) {
357 kfree(msg);
358 return -EFAULT;
359 }
360
361 msg[count] = '\0';
362 bt = filp->private_data;
363 __trace_note_message(bt, "%s", msg);
364 kfree(msg);
365
366 return count;
367}
368
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 *old_bt, *bt = NULL;
441 struct dentry *dir = NULL;
442 int ret, i;
443
444 if (!buts->buf_size || !buts->buf_nr)
445 return -EINVAL;
446
447 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
448 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
449
450 /*
451 * some device names have larger paths - convert the slashes
452 * to underscores for this to work as expected
453 */
454 for (i = 0; i < strlen(buts->name); i++)
455 if (buts->name[i] == '/')
456 buts->name[i] = '_';
457
458 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
459 if (!bt)
460 return -ENOMEM;
461
462 ret = -ENOMEM;
463 bt->sequence = alloc_percpu(unsigned long);
464 if (!bt->sequence)
465 goto err;
466
467 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
468 if (!bt->msg_data)
469 goto err;
470
471 ret = -ENOENT;
472
473 mutex_lock(&blk_tree_mutex);
474 if (!blk_tree_root) {
475 blk_tree_root = debugfs_create_dir("block", NULL);
476 if (!blk_tree_root) {
477 mutex_unlock(&blk_tree_mutex);
478 goto err;
479 }
480 }
481 mutex_unlock(&blk_tree_mutex);
482
483 dir = debugfs_create_dir(buts->name, blk_tree_root);
484
485 if (!dir)
486 goto err;
487
488 bt->dir = dir;
489 bt->dev = dev;
490 atomic_set(&bt->dropped, 0);
491 INIT_LIST_HEAD(&bt->running_list);
492
493 ret = -EIO;
494 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
495 &blk_dropped_fops);
496 if (!bt->dropped_file)
497 goto err;
498
499 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
500 if (!bt->msg_file)
501 goto err;
502
503 bt->rchan = relay_open("trace", dir, buts->buf_size,
504 buts->buf_nr, &blk_relay_callbacks, bt);
505 if (!bt->rchan)
506 goto err;
507
508 bt->act_mask = buts->act_mask;
509 if (!bt->act_mask)
510 bt->act_mask = (u16) -1;
511
512 blk_trace_setup_lba(bt, bdev);
513
514 /* overwrite with user settings */
515 if (buts->start_lba)
516 bt->start_lba = buts->start_lba;
517 if (buts->end_lba)
518 bt->end_lba = buts->end_lba;
519
520 bt->pid = buts->pid;
521 bt->trace_state = Blktrace_setup;
522
523 ret = -EBUSY;
524 old_bt = xchg(&q->blk_trace, bt);
525 if (old_bt) {
526 (void) xchg(&q->blk_trace, old_bt);
527 goto err;
528 }
529
530 if (atomic_inc_return(&blk_probes_ref) == 1)
531 blk_register_tracepoints();
532
533 return 0;
534err:
535 blk_trace_free(bt);
536 return ret;
537}
538
539int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
540 struct block_device *bdev,
541 char __user *arg)
542{
543 struct blk_user_trace_setup buts;
544 int ret;
545
546 ret = copy_from_user(&buts, arg, sizeof(buts));
547 if (ret)
548 return -EFAULT;
549
550 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
551 if (ret)
552 return ret;
553
554 if (copy_to_user(arg, &buts, sizeof(buts))) {
555 blk_trace_remove(q);
556 return -EFAULT;
557 }
558 return 0;
559}
560EXPORT_SYMBOL_GPL(blk_trace_setup);
561
562#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
563static int compat_blk_trace_setup(struct request_queue *q, char *name,
564 dev_t dev, struct block_device *bdev,
565 char __user *arg)
566{
567 struct blk_user_trace_setup buts;
568 struct compat_blk_user_trace_setup cbuts;
569 int ret;
570
571 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
572 return -EFAULT;
573
574 buts = (struct blk_user_trace_setup) {
575 .act_mask = cbuts.act_mask,
576 .buf_size = cbuts.buf_size,
577 .buf_nr = cbuts.buf_nr,
578 .start_lba = cbuts.start_lba,
579 .end_lba = cbuts.end_lba,
580 .pid = cbuts.pid,
581 };
582
583 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
584 if (ret)
585 return ret;
586
587 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
588 blk_trace_remove(q);
589 return -EFAULT;
590 }
591
592 return 0;
593}
594#endif
595
596int blk_trace_startstop(struct request_queue *q, int start)
597{
598 int ret;
599 struct blk_trace *bt = q->blk_trace;
600
601 if (bt == NULL)
602 return -EINVAL;
603
604 /*
605 * For starting a trace, we can transition from a setup or stopped
606 * trace. For stopping a trace, the state must be running
607 */
608 ret = -EINVAL;
609 if (start) {
610 if (bt->trace_state == Blktrace_setup ||
611 bt->trace_state == Blktrace_stopped) {
612 blktrace_seq++;
613 smp_mb();
614 bt->trace_state = Blktrace_running;
615 spin_lock_irq(&running_trace_lock);
616 list_add(&bt->running_list, &running_trace_list);
617 spin_unlock_irq(&running_trace_lock);
618
619 trace_note_time(bt);
620 ret = 0;
621 }
622 } else {
623 if (bt->trace_state == Blktrace_running) {
624 bt->trace_state = Blktrace_stopped;
625 spin_lock_irq(&running_trace_lock);
626 list_del_init(&bt->running_list);
627 spin_unlock_irq(&running_trace_lock);
628 relay_flush(bt->rchan);
629 ret = 0;
630 }
631 }
632
633 return ret;
634}
635EXPORT_SYMBOL_GPL(blk_trace_startstop);
636
637/**
638 * blk_trace_ioctl: - handle the ioctls associated with tracing
639 * @bdev: the block device
640 * @cmd: the ioctl cmd
641 * @arg: the argument data, if any
642 *
643 **/
644int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
645{
646 struct request_queue *q;
647 int ret, start = 0;
648 char b[BDEVNAME_SIZE];
649
650 q = bdev_get_queue(bdev);
651 if (!q)
652 return -ENXIO;
653
654 mutex_lock(&bdev->bd_mutex);
655
656 switch (cmd) {
657 case BLKTRACESETUP:
658 bdevname(bdev, b);
659 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
660 break;
661#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
662 case BLKTRACESETUP32:
663 bdevname(bdev, b);
664 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
665 break;
666#endif
667 case BLKTRACESTART:
668 start = 1;
669 case BLKTRACESTOP:
670 ret = blk_trace_startstop(q, start);
671 break;
672 case BLKTRACETEARDOWN:
673 ret = blk_trace_remove(q);
674 break;
675 default:
676 ret = -ENOTTY;
677 break;
678 }
679
680 mutex_unlock(&bdev->bd_mutex);
681 return ret;
682}
683
684/**
685 * blk_trace_shutdown: - stop and cleanup trace structures
686 * @q: the request queue associated with the device
687 *
688 **/
689void blk_trace_shutdown(struct request_queue *q)
690{
691 if (q->blk_trace) {
692 blk_trace_startstop(q, 0);
693 blk_trace_remove(q);
694 }
695}
696
697/*
698 * blktrace probes
699 */
700
701/**
702 * blk_add_trace_rq - Add a trace for a request oriented action
703 * @q: queue the io is for
704 * @rq: the source request
705 * @nr_bytes: number of completed bytes
706 * @what: the action
707 *
708 * Description:
709 * Records an action against a request. Will log the bio offset + size.
710 *
711 **/
712static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
713 unsigned int nr_bytes, u32 what)
714{
715 struct blk_trace *bt = q->blk_trace;
716
717 if (likely(!bt))
718 return;
719
720 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
721 what |= BLK_TC_ACT(BLK_TC_PC);
722 __blk_add_trace(bt, 0, nr_bytes, rq->cmd_flags,
723 what, rq->errors, rq->cmd_len, rq->cmd);
724 } else {
725 what |= BLK_TC_ACT(BLK_TC_FS);
726 __blk_add_trace(bt, blk_rq_pos(rq), nr_bytes,
727 rq->cmd_flags, what, rq->errors, 0, NULL);
728 }
729}
730
731static void blk_add_trace_rq_abort(void *ignore,
732 struct request_queue *q, struct request *rq)
733{
734 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT);
735}
736
737static void blk_add_trace_rq_insert(void *ignore,
738 struct request_queue *q, struct request *rq)
739{
740 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT);
741}
742
743static void blk_add_trace_rq_issue(void *ignore,
744 struct request_queue *q, struct request *rq)
745{
746 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE);
747}
748
749static void blk_add_trace_rq_requeue(void *ignore,
750 struct request_queue *q,
751 struct request *rq)
752{
753 blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE);
754}
755
756static void blk_add_trace_rq_complete(void *ignore,
757 struct request_queue *q,
758 struct request *rq,
759 unsigned int nr_bytes)
760{
761 blk_add_trace_rq(q, rq, nr_bytes, BLK_TA_COMPLETE);
762}
763
764/**
765 * blk_add_trace_bio - Add a trace for a bio oriented action
766 * @q: queue the io is for
767 * @bio: the source bio
768 * @what: the action
769 * @error: error, if any
770 *
771 * Description:
772 * Records an action against a bio. Will log the bio offset + size.
773 *
774 **/
775static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
776 u32 what, int error)
777{
778 struct blk_trace *bt = q->blk_trace;
779
780 if (likely(!bt))
781 return;
782
783 if (!error && !bio_flagged(bio, BIO_UPTODATE))
784 error = EIO;
785
786 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
787 bio->bi_rw, what, error, 0, NULL);
788}
789
790static void blk_add_trace_bio_bounce(void *ignore,
791 struct request_queue *q, struct bio *bio)
792{
793 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
794}
795
796static void blk_add_trace_bio_complete(void *ignore,
797 struct request_queue *q, struct bio *bio,
798 int error)
799{
800 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
801}
802
803static void blk_add_trace_bio_backmerge(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_BACKMERGE, 0);
809}
810
811static void blk_add_trace_bio_frontmerge(void *ignore,
812 struct request_queue *q,
813 struct request *rq,
814 struct bio *bio)
815{
816 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
817}
818
819static void blk_add_trace_bio_queue(void *ignore,
820 struct request_queue *q, struct bio *bio)
821{
822 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
823}
824
825static void blk_add_trace_getrq(void *ignore,
826 struct request_queue *q,
827 struct bio *bio, int rw)
828{
829 if (bio)
830 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
831 else {
832 struct blk_trace *bt = q->blk_trace;
833
834 if (bt)
835 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
836 }
837}
838
839
840static void blk_add_trace_sleeprq(void *ignore,
841 struct request_queue *q,
842 struct bio *bio, int rw)
843{
844 if (bio)
845 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
846 else {
847 struct blk_trace *bt = q->blk_trace;
848
849 if (bt)
850 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
851 0, 0, NULL);
852 }
853}
854
855static void blk_add_trace_plug(void *ignore, struct request_queue *q)
856{
857 struct blk_trace *bt = q->blk_trace;
858
859 if (bt)
860 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
861}
862
863static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
864 unsigned int depth, bool explicit)
865{
866 struct blk_trace *bt = q->blk_trace;
867
868 if (bt) {
869 __be64 rpdu = cpu_to_be64(depth);
870 u32 what;
871
872 if (explicit)
873 what = BLK_TA_UNPLUG_IO;
874 else
875 what = BLK_TA_UNPLUG_TIMER;
876
877 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
878 }
879}
880
881static void blk_add_trace_split(void *ignore,
882 struct request_queue *q, struct bio *bio,
883 unsigned int pdu)
884{
885 struct blk_trace *bt = q->blk_trace;
886
887 if (bt) {
888 __be64 rpdu = cpu_to_be64(pdu);
889
890 __blk_add_trace(bt, bio->bi_iter.bi_sector,
891 bio->bi_iter.bi_size, bio->bi_rw, BLK_TA_SPLIT,
892 !bio_flagged(bio, BIO_UPTODATE),
893 sizeof(rpdu), &rpdu);
894 }
895}
896
897/**
898 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
899 * @ignore: trace callback data parameter (not used)
900 * @q: queue the io is for
901 * @bio: the source bio
902 * @dev: target device
903 * @from: source sector
904 *
905 * Description:
906 * Device mapper or raid target sometimes need to split a bio because
907 * it spans a stripe (or similar). Add a trace for that action.
908 *
909 **/
910static void blk_add_trace_bio_remap(void *ignore,
911 struct request_queue *q, struct bio *bio,
912 dev_t dev, sector_t from)
913{
914 struct blk_trace *bt = q->blk_trace;
915 struct blk_io_trace_remap r;
916
917 if (likely(!bt))
918 return;
919
920 r.device_from = cpu_to_be32(dev);
921 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
922 r.sector_from = cpu_to_be64(from);
923
924 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
925 bio->bi_rw, BLK_TA_REMAP,
926 !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
927}
928
929/**
930 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
931 * @ignore: trace callback data parameter (not used)
932 * @q: queue the io is for
933 * @rq: the source request
934 * @dev: target device
935 * @from: source sector
936 *
937 * Description:
938 * Device mapper remaps request to other devices.
939 * Add a trace for that action.
940 *
941 **/
942static void blk_add_trace_rq_remap(void *ignore,
943 struct request_queue *q,
944 struct request *rq, dev_t dev,
945 sector_t from)
946{
947 struct blk_trace *bt = q->blk_trace;
948 struct blk_io_trace_remap r;
949
950 if (likely(!bt))
951 return;
952
953 r.device_from = cpu_to_be32(dev);
954 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
955 r.sector_from = cpu_to_be64(from);
956
957 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
958 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
959 sizeof(r), &r);
960}
961
962/**
963 * blk_add_driver_data - Add binary message with driver-specific data
964 * @q: queue the io is for
965 * @rq: io request
966 * @data: driver-specific data
967 * @len: length of driver-specific data
968 *
969 * Description:
970 * Some drivers might want to write driver-specific data per request.
971 *
972 **/
973void blk_add_driver_data(struct request_queue *q,
974 struct request *rq,
975 void *data, size_t len)
976{
977 struct blk_trace *bt = q->blk_trace;
978
979 if (likely(!bt))
980 return;
981
982 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
983 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
984 BLK_TA_DRV_DATA, rq->errors, len, data);
985 else
986 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
987 BLK_TA_DRV_DATA, rq->errors, len, data);
988}
989EXPORT_SYMBOL_GPL(blk_add_driver_data);
990
991static void blk_register_tracepoints(void)
992{
993 int ret;
994
995 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1006 WARN_ON(ret);
1007 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1008 WARN_ON(ret);
1009 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1010 WARN_ON(ret);
1011 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1012 WARN_ON(ret);
1013 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1014 WARN_ON(ret);
1015 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1016 WARN_ON(ret);
1017 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1018 WARN_ON(ret);
1019 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1020 WARN_ON(ret);
1021 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1022 WARN_ON(ret);
1023 ret = register_trace_block_split(blk_add_trace_split, NULL);
1024 WARN_ON(ret);
1025 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1026 WARN_ON(ret);
1027 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1028 WARN_ON(ret);
1029}
1030
1031static void blk_unregister_tracepoints(void)
1032{
1033 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1034 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1035 unregister_trace_block_split(blk_add_trace_split, NULL);
1036 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1037 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1038 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1039 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1040 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1041 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1042 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1043 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1044 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1045 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1046 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1047 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1048 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1049 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1050
1051 tracepoint_synchronize_unregister();
1052}
1053
1054/*
1055 * struct blk_io_tracer formatting routines
1056 */
1057
1058static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1059{
1060 int i = 0;
1061 int tc = t->action >> BLK_TC_SHIFT;
1062
1063 if (t->action == BLK_TN_MESSAGE) {
1064 rwbs[i++] = 'N';
1065 goto out;
1066 }
1067
1068 if (tc & BLK_TC_FLUSH)
1069 rwbs[i++] = 'F';
1070
1071 if (tc & BLK_TC_DISCARD)
1072 rwbs[i++] = 'D';
1073 else if (tc & BLK_TC_WRITE)
1074 rwbs[i++] = 'W';
1075 else if (t->bytes)
1076 rwbs[i++] = 'R';
1077 else
1078 rwbs[i++] = 'N';
1079
1080 if (tc & BLK_TC_FUA)
1081 rwbs[i++] = 'F';
1082 if (tc & BLK_TC_AHEAD)
1083 rwbs[i++] = 'A';
1084 if (tc & BLK_TC_SYNC)
1085 rwbs[i++] = 'S';
1086 if (tc & BLK_TC_META)
1087 rwbs[i++] = 'M';
1088out:
1089 rwbs[i] = '\0';
1090}
1091
1092static inline
1093const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1094{
1095 return (const struct blk_io_trace *)ent;
1096}
1097
1098static inline const void *pdu_start(const struct trace_entry *ent)
1099{
1100 return te_blk_io_trace(ent) + 1;
1101}
1102
1103static inline u32 t_action(const struct trace_entry *ent)
1104{
1105 return te_blk_io_trace(ent)->action;
1106}
1107
1108static inline u32 t_bytes(const struct trace_entry *ent)
1109{
1110 return te_blk_io_trace(ent)->bytes;
1111}
1112
1113static inline u32 t_sec(const struct trace_entry *ent)
1114{
1115 return te_blk_io_trace(ent)->bytes >> 9;
1116}
1117
1118static inline unsigned long long t_sector(const struct trace_entry *ent)
1119{
1120 return te_blk_io_trace(ent)->sector;
1121}
1122
1123static inline __u16 t_error(const struct trace_entry *ent)
1124{
1125 return te_blk_io_trace(ent)->error;
1126}
1127
1128static __u64 get_pdu_int(const struct trace_entry *ent)
1129{
1130 const __u64 *val = pdu_start(ent);
1131 return be64_to_cpu(*val);
1132}
1133
1134static void get_pdu_remap(const struct trace_entry *ent,
1135 struct blk_io_trace_remap *r)
1136{
1137 const struct blk_io_trace_remap *__r = pdu_start(ent);
1138 __u64 sector_from = __r->sector_from;
1139
1140 r->device_from = be32_to_cpu(__r->device_from);
1141 r->device_to = be32_to_cpu(__r->device_to);
1142 r->sector_from = be64_to_cpu(sector_from);
1143}
1144
1145typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1146
1147static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1148{
1149 char rwbs[RWBS_LEN];
1150 unsigned long long ts = iter->ts;
1151 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1152 unsigned secs = (unsigned long)ts;
1153 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1154
1155 fill_rwbs(rwbs, t);
1156
1157 return trace_seq_printf(&iter->seq,
1158 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1159 MAJOR(t->device), MINOR(t->device), iter->cpu,
1160 secs, nsec_rem, iter->ent->pid, act, rwbs);
1161}
1162
1163static int blk_log_action(struct trace_iterator *iter, const char *act)
1164{
1165 char rwbs[RWBS_LEN];
1166 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1167
1168 fill_rwbs(rwbs, t);
1169 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1170 MAJOR(t->device), MINOR(t->device), act, rwbs);
1171}
1172
1173static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1174{
1175 const unsigned char *pdu_buf;
1176 int pdu_len;
1177 int i, end, ret;
1178
1179 pdu_buf = pdu_start(ent);
1180 pdu_len = te_blk_io_trace(ent)->pdu_len;
1181
1182 if (!pdu_len)
1183 return 1;
1184
1185 /* find the last zero that needs to be printed */
1186 for (end = pdu_len - 1; end >= 0; end--)
1187 if (pdu_buf[end])
1188 break;
1189 end++;
1190
1191 if (!trace_seq_putc(s, '('))
1192 return 0;
1193
1194 for (i = 0; i < pdu_len; i++) {
1195
1196 ret = trace_seq_printf(s, "%s%02x",
1197 i == 0 ? "" : " ", pdu_buf[i]);
1198 if (!ret)
1199 return ret;
1200
1201 /*
1202 * stop when the rest is just zeroes and indicate so
1203 * with a ".." appended
1204 */
1205 if (i == end && end != pdu_len - 1)
1206 return trace_seq_puts(s, " ..) ");
1207 }
1208
1209 return trace_seq_puts(s, ") ");
1210}
1211
1212static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1213{
1214 char cmd[TASK_COMM_LEN];
1215
1216 trace_find_cmdline(ent->pid, cmd);
1217
1218 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1219 int ret;
1220
1221 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1222 if (!ret)
1223 return 0;
1224 ret = blk_log_dump_pdu(s, ent);
1225 if (!ret)
1226 return 0;
1227 return trace_seq_printf(s, "[%s]\n", cmd);
1228 } else {
1229 if (t_sec(ent))
1230 return trace_seq_printf(s, "%llu + %u [%s]\n",
1231 t_sector(ent), t_sec(ent), cmd);
1232 return trace_seq_printf(s, "[%s]\n", cmd);
1233 }
1234}
1235
1236static int blk_log_with_error(struct trace_seq *s,
1237 const struct trace_entry *ent)
1238{
1239 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1240 int ret;
1241
1242 ret = blk_log_dump_pdu(s, ent);
1243 if (ret)
1244 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1245 return 0;
1246 } else {
1247 if (t_sec(ent))
1248 return trace_seq_printf(s, "%llu + %u [%d]\n",
1249 t_sector(ent),
1250 t_sec(ent), t_error(ent));
1251 return trace_seq_printf(s, "%llu [%d]\n",
1252 t_sector(ent), t_error(ent));
1253 }
1254}
1255
1256static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1257{
1258 struct blk_io_trace_remap r = { .device_from = 0, };
1259
1260 get_pdu_remap(ent, &r);
1261 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1262 t_sector(ent), t_sec(ent),
1263 MAJOR(r.device_from), MINOR(r.device_from),
1264 (unsigned long long)r.sector_from);
1265}
1266
1267static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1268{
1269 char cmd[TASK_COMM_LEN];
1270
1271 trace_find_cmdline(ent->pid, cmd);
1272
1273 return trace_seq_printf(s, "[%s]\n", cmd);
1274}
1275
1276static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1277{
1278 char cmd[TASK_COMM_LEN];
1279
1280 trace_find_cmdline(ent->pid, cmd);
1281
1282 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1283}
1284
1285static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1286{
1287 char cmd[TASK_COMM_LEN];
1288
1289 trace_find_cmdline(ent->pid, cmd);
1290
1291 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1292 get_pdu_int(ent), cmd);
1293}
1294
1295static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1296{
1297 int ret;
1298 const struct blk_io_trace *t = te_blk_io_trace(ent);
1299
1300 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1301 if (ret)
1302 return trace_seq_putc(s, '\n');
1303 return ret;
1304}
1305
1306/*
1307 * struct tracer operations
1308 */
1309
1310static void blk_tracer_print_header(struct seq_file *m)
1311{
1312 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1313 return;
1314 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1315 "# | | | | | |\n");
1316}
1317
1318static void blk_tracer_start(struct trace_array *tr)
1319{
1320 blk_tracer_enabled = true;
1321}
1322
1323static int blk_tracer_init(struct trace_array *tr)
1324{
1325 blk_tr = tr;
1326 blk_tracer_start(tr);
1327 return 0;
1328}
1329
1330static void blk_tracer_stop(struct trace_array *tr)
1331{
1332 blk_tracer_enabled = false;
1333}
1334
1335static void blk_tracer_reset(struct trace_array *tr)
1336{
1337 blk_tracer_stop(tr);
1338}
1339
1340static const struct {
1341 const char *act[2];
1342 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1343} what2act[] = {
1344 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1345 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1346 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1347 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1348 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1349 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1350 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1351 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1352 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1353 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1354 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1355 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1356 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1357 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1358 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1359};
1360
1361static enum print_line_t print_one_line(struct trace_iterator *iter,
1362 bool classic)
1363{
1364 struct trace_seq *s = &iter->seq;
1365 const struct blk_io_trace *t;
1366 u16 what;
1367 int ret;
1368 bool long_act;
1369 blk_log_action_t *log_action;
1370
1371 t = te_blk_io_trace(iter->ent);
1372 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1373 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1374 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1375
1376 if (t->action == BLK_TN_MESSAGE) {
1377 ret = log_action(iter, long_act ? "message" : "m");
1378 if (ret)
1379 ret = blk_log_msg(s, iter->ent);
1380 goto out;
1381 }
1382
1383 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1384 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1385 else {
1386 ret = log_action(iter, what2act[what].act[long_act]);
1387 if (ret)
1388 ret = what2act[what].print(s, iter->ent);
1389 }
1390out:
1391 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1392}
1393
1394static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1395 int flags, struct trace_event *event)
1396{
1397 return print_one_line(iter, false);
1398}
1399
1400static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1401{
1402 struct trace_seq *s = &iter->seq;
1403 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1404 const int offset = offsetof(struct blk_io_trace, sector);
1405 struct blk_io_trace old = {
1406 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1407 .time = iter->ts,
1408 };
1409
1410 if (!trace_seq_putmem(s, &old, offset))
1411 return 0;
1412 return trace_seq_putmem(s, &t->sector,
1413 sizeof(old) - offset + t->pdu_len);
1414}
1415
1416static enum print_line_t
1417blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1418 struct trace_event *event)
1419{
1420 return blk_trace_synthesize_old_trace(iter) ?
1421 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1422}
1423
1424static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1425{
1426 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1427 return TRACE_TYPE_UNHANDLED;
1428
1429 return print_one_line(iter, true);
1430}
1431
1432static int
1433blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1434{
1435 /* don't output context-info for blk_classic output */
1436 if (bit == TRACE_BLK_OPT_CLASSIC) {
1437 if (set)
1438 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1439 else
1440 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1441 }
1442 return 0;
1443}
1444
1445static struct tracer blk_tracer __read_mostly = {
1446 .name = "blk",
1447 .init = blk_tracer_init,
1448 .reset = blk_tracer_reset,
1449 .start = blk_tracer_start,
1450 .stop = blk_tracer_stop,
1451 .print_header = blk_tracer_print_header,
1452 .print_line = blk_tracer_print_line,
1453 .flags = &blk_tracer_flags,
1454 .set_flag = blk_tracer_set_flag,
1455};
1456
1457static struct trace_event_functions trace_blk_event_funcs = {
1458 .trace = blk_trace_event_print,
1459 .binary = blk_trace_event_print_binary,
1460};
1461
1462static struct trace_event trace_blk_event = {
1463 .type = TRACE_BLK,
1464 .funcs = &trace_blk_event_funcs,
1465};
1466
1467static int __init init_blk_tracer(void)
1468{
1469 if (!register_ftrace_event(&trace_blk_event)) {
1470 pr_warning("Warning: could not register block events\n");
1471 return 1;
1472 }
1473
1474 if (register_tracer(&blk_tracer) != 0) {
1475 pr_warning("Warning: could not register the block tracer\n");
1476 unregister_ftrace_event(&trace_blk_event);
1477 return 1;
1478 }
1479
1480 return 0;
1481}
1482
1483device_initcall(init_blk_tracer);
1484
1485static int blk_trace_remove_queue(struct request_queue *q)
1486{
1487 struct blk_trace *bt;
1488
1489 bt = xchg(&q->blk_trace, NULL);
1490 if (bt == NULL)
1491 return -EINVAL;
1492
1493 if (atomic_dec_and_test(&blk_probes_ref))
1494 blk_unregister_tracepoints();
1495
1496 spin_lock_irq(&running_trace_lock);
1497 list_del(&bt->running_list);
1498 spin_unlock_irq(&running_trace_lock);
1499 blk_trace_free(bt);
1500 return 0;
1501}
1502
1503/*
1504 * Setup everything required to start tracing
1505 */
1506static int blk_trace_setup_queue(struct request_queue *q,
1507 struct block_device *bdev)
1508{
1509 struct blk_trace *old_bt, *bt = NULL;
1510 int ret = -ENOMEM;
1511
1512 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1513 if (!bt)
1514 return -ENOMEM;
1515
1516 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1517 if (!bt->msg_data)
1518 goto free_bt;
1519
1520 bt->dev = bdev->bd_dev;
1521 bt->act_mask = (u16)-1;
1522
1523 blk_trace_setup_lba(bt, bdev);
1524
1525 old_bt = xchg(&q->blk_trace, bt);
1526 if (old_bt != NULL) {
1527 (void)xchg(&q->blk_trace, old_bt);
1528 ret = -EBUSY;
1529 goto free_bt;
1530 }
1531
1532 if (atomic_inc_return(&blk_probes_ref) == 1)
1533 blk_register_tracepoints();
1534 return 0;
1535
1536free_bt:
1537 blk_trace_free(bt);
1538 return ret;
1539}
1540
1541/*
1542 * sysfs interface to enable and configure tracing
1543 */
1544
1545static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1546 struct device_attribute *attr,
1547 char *buf);
1548static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1549 struct device_attribute *attr,
1550 const char *buf, size_t count);
1551#define BLK_TRACE_DEVICE_ATTR(_name) \
1552 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1553 sysfs_blk_trace_attr_show, \
1554 sysfs_blk_trace_attr_store)
1555
1556static BLK_TRACE_DEVICE_ATTR(enable);
1557static BLK_TRACE_DEVICE_ATTR(act_mask);
1558static BLK_TRACE_DEVICE_ATTR(pid);
1559static BLK_TRACE_DEVICE_ATTR(start_lba);
1560static BLK_TRACE_DEVICE_ATTR(end_lba);
1561
1562static struct attribute *blk_trace_attrs[] = {
1563 &dev_attr_enable.attr,
1564 &dev_attr_act_mask.attr,
1565 &dev_attr_pid.attr,
1566 &dev_attr_start_lba.attr,
1567 &dev_attr_end_lba.attr,
1568 NULL
1569};
1570
1571struct attribute_group blk_trace_attr_group = {
1572 .name = "trace",
1573 .attrs = blk_trace_attrs,
1574};
1575
1576static const struct {
1577 int mask;
1578 const char *str;
1579} mask_maps[] = {
1580 { BLK_TC_READ, "read" },
1581 { BLK_TC_WRITE, "write" },
1582 { BLK_TC_FLUSH, "flush" },
1583 { BLK_TC_SYNC, "sync" },
1584 { BLK_TC_QUEUE, "queue" },
1585 { BLK_TC_REQUEUE, "requeue" },
1586 { BLK_TC_ISSUE, "issue" },
1587 { BLK_TC_COMPLETE, "complete" },
1588 { BLK_TC_FS, "fs" },
1589 { BLK_TC_PC, "pc" },
1590 { BLK_TC_AHEAD, "ahead" },
1591 { BLK_TC_META, "meta" },
1592 { BLK_TC_DISCARD, "discard" },
1593 { BLK_TC_DRV_DATA, "drv_data" },
1594 { BLK_TC_FUA, "fua" },
1595};
1596
1597static int blk_trace_str2mask(const char *str)
1598{
1599 int i;
1600 int mask = 0;
1601 char *buf, *s, *token;
1602
1603 buf = kstrdup(str, GFP_KERNEL);
1604 if (buf == NULL)
1605 return -ENOMEM;
1606 s = strstrip(buf);
1607
1608 while (1) {
1609 token = strsep(&s, ",");
1610 if (token == NULL)
1611 break;
1612
1613 if (*token == '\0')
1614 continue;
1615
1616 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1617 if (strcasecmp(token, mask_maps[i].str) == 0) {
1618 mask |= mask_maps[i].mask;
1619 break;
1620 }
1621 }
1622 if (i == ARRAY_SIZE(mask_maps)) {
1623 mask = -EINVAL;
1624 break;
1625 }
1626 }
1627 kfree(buf);
1628
1629 return mask;
1630}
1631
1632static ssize_t blk_trace_mask2str(char *buf, int mask)
1633{
1634 int i;
1635 char *p = buf;
1636
1637 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1638 if (mask & mask_maps[i].mask) {
1639 p += sprintf(p, "%s%s",
1640 (p == buf) ? "" : ",", mask_maps[i].str);
1641 }
1642 }
1643 *p++ = '\n';
1644
1645 return p - buf;
1646}
1647
1648static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1649{
1650 if (bdev->bd_disk == NULL)
1651 return NULL;
1652
1653 return bdev_get_queue(bdev);
1654}
1655
1656static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1657 struct device_attribute *attr,
1658 char *buf)
1659{
1660 struct hd_struct *p = dev_to_part(dev);
1661 struct request_queue *q;
1662 struct block_device *bdev;
1663 ssize_t ret = -ENXIO;
1664
1665 bdev = bdget(part_devt(p));
1666 if (bdev == NULL)
1667 goto out;
1668
1669 q = blk_trace_get_queue(bdev);
1670 if (q == NULL)
1671 goto out_bdput;
1672
1673 mutex_lock(&bdev->bd_mutex);
1674
1675 if (attr == &dev_attr_enable) {
1676 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1677 goto out_unlock_bdev;
1678 }
1679
1680 if (q->blk_trace == NULL)
1681 ret = sprintf(buf, "disabled\n");
1682 else if (attr == &dev_attr_act_mask)
1683 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1684 else if (attr == &dev_attr_pid)
1685 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1686 else if (attr == &dev_attr_start_lba)
1687 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1688 else if (attr == &dev_attr_end_lba)
1689 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1690
1691out_unlock_bdev:
1692 mutex_unlock(&bdev->bd_mutex);
1693out_bdput:
1694 bdput(bdev);
1695out:
1696 return ret;
1697}
1698
1699static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1700 struct device_attribute *attr,
1701 const char *buf, size_t count)
1702{
1703 struct block_device *bdev;
1704 struct request_queue *q;
1705 struct hd_struct *p;
1706 u64 value;
1707 ssize_t ret = -EINVAL;
1708
1709 if (count == 0)
1710 goto out;
1711
1712 if (attr == &dev_attr_act_mask) {
1713 if (sscanf(buf, "%llx", &value) != 1) {
1714 /* Assume it is a list of trace category names */
1715 ret = blk_trace_str2mask(buf);
1716 if (ret < 0)
1717 goto out;
1718 value = ret;
1719 }
1720 } else if (sscanf(buf, "%llu", &value) != 1)
1721 goto out;
1722
1723 ret = -ENXIO;
1724
1725 p = dev_to_part(dev);
1726 bdev = bdget(part_devt(p));
1727 if (bdev == NULL)
1728 goto out;
1729
1730 q = blk_trace_get_queue(bdev);
1731 if (q == NULL)
1732 goto out_bdput;
1733
1734 mutex_lock(&bdev->bd_mutex);
1735
1736 if (attr == &dev_attr_enable) {
1737 if (value)
1738 ret = blk_trace_setup_queue(q, bdev);
1739 else
1740 ret = blk_trace_remove_queue(q);
1741 goto out_unlock_bdev;
1742 }
1743
1744 ret = 0;
1745 if (q->blk_trace == NULL)
1746 ret = blk_trace_setup_queue(q, bdev);
1747
1748 if (ret == 0) {
1749 if (attr == &dev_attr_act_mask)
1750 q->blk_trace->act_mask = value;
1751 else if (attr == &dev_attr_pid)
1752 q->blk_trace->pid = value;
1753 else if (attr == &dev_attr_start_lba)
1754 q->blk_trace->start_lba = value;
1755 else if (attr == &dev_attr_end_lba)
1756 q->blk_trace->end_lba = value;
1757 }
1758
1759out_unlock_bdev:
1760 mutex_unlock(&bdev->bd_mutex);
1761out_bdput:
1762 bdput(bdev);
1763out:
1764 return ret ? ret : count;
1765}
1766
1767int blk_trace_init_sysfs(struct device *dev)
1768{
1769 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1770}
1771
1772void blk_trace_remove_sysfs(struct device *dev)
1773{
1774 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1775}
1776
1777#endif /* CONFIG_BLK_DEV_IO_TRACE */
1778
1779#ifdef CONFIG_EVENT_TRACING
1780
1781void blk_dump_cmd(char *buf, struct request *rq)
1782{
1783 int i, end;
1784 int len = rq->cmd_len;
1785 unsigned char *cmd = rq->cmd;
1786
1787 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1788 buf[0] = '\0';
1789 return;
1790 }
1791
1792 for (end = len - 1; end >= 0; end--)
1793 if (cmd[end])
1794 break;
1795 end++;
1796
1797 for (i = 0; i < len; i++) {
1798 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1799 if (i == end && end != len - 1) {
1800 sprintf(buf, " ..");
1801 break;
1802 }
1803 }
1804}
1805
1806void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1807{
1808 int i = 0;
1809
1810 if (rw & REQ_FLUSH)
1811 rwbs[i++] = 'F';
1812
1813 if (rw & WRITE)
1814 rwbs[i++] = 'W';
1815 else if (rw & REQ_DISCARD)
1816 rwbs[i++] = 'D';
1817 else if (bytes)
1818 rwbs[i++] = 'R';
1819 else
1820 rwbs[i++] = 'N';
1821
1822 if (rw & REQ_FUA)
1823 rwbs[i++] = 'F';
1824 if (rw & REQ_RAHEAD)
1825 rwbs[i++] = 'A';
1826 if (rw & REQ_SYNC)
1827 rwbs[i++] = 'S';
1828 if (rw & REQ_META)
1829 rwbs[i++] = 'M';
1830 if (rw & REQ_SECURE)
1831 rwbs[i++] = 'E';
1832
1833 rwbs[i] = '\0';
1834}
1835EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1836
1837#endif /* CONFIG_EVENT_TRACING */
1838
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#include <linux/blk-cgroup.h>
31
32#include "../../block/blk.h"
33
34#include <trace/events/block.h>
35
36#include "trace_output.h"
37
38#ifdef CONFIG_BLK_DEV_IO_TRACE
39
40static unsigned int blktrace_seq __read_mostly = 1;
41
42static struct trace_array *blk_tr;
43static bool blk_tracer_enabled __read_mostly;
44
45static LIST_HEAD(running_trace_list);
46static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
47
48/* Select an alternative, minimalistic output than the original one */
49#define TRACE_BLK_OPT_CLASSIC 0x1
50#define TRACE_BLK_OPT_CGROUP 0x2
51#define TRACE_BLK_OPT_CGNAME 0x4
52
53static struct tracer_opt blk_tracer_opts[] = {
54 /* Default disable the minimalistic output */
55 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
56#ifdef CONFIG_BLK_CGROUP
57 { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
58 { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
59#endif
60 { }
61};
62
63static struct tracer_flags blk_tracer_flags = {
64 .val = 0,
65 .opts = blk_tracer_opts,
66};
67
68/* Global reference count of probes */
69static DEFINE_MUTEX(blk_probe_mutex);
70static int blk_probes_ref;
71
72static void blk_register_tracepoints(void);
73static void blk_unregister_tracepoints(void);
74
75/*
76 * Send out a notify message.
77 */
78static void trace_note(struct blk_trace *bt, pid_t pid, int action,
79 const void *data, size_t len,
80 union kernfs_node_id *cgid)
81{
82 struct blk_io_trace *t;
83 struct ring_buffer_event *event = NULL;
84 struct ring_buffer *buffer = NULL;
85 int pc = 0;
86 int cpu = smp_processor_id();
87 bool blk_tracer = blk_tracer_enabled;
88 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
89
90 if (blk_tracer) {
91 buffer = blk_tr->trace_buffer.buffer;
92 pc = preempt_count();
93 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
94 sizeof(*t) + len + cgid_len,
95 0, pc);
96 if (!event)
97 return;
98 t = ring_buffer_event_data(event);
99 goto record_it;
100 }
101
102 if (!bt->rchan)
103 return;
104
105 t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len);
106 if (t) {
107 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
108 t->time = ktime_to_ns(ktime_get());
109record_it:
110 t->device = bt->dev;
111 t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
112 t->pid = pid;
113 t->cpu = cpu;
114 t->pdu_len = len + cgid_len;
115 if (cgid)
116 memcpy((void *)t + sizeof(*t), cgid, cgid_len);
117 memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
118
119 if (blk_tracer)
120 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
121 }
122}
123
124/*
125 * Send out a notify for this process, if we haven't done so since a trace
126 * started
127 */
128static void trace_note_tsk(struct task_struct *tsk)
129{
130 unsigned long flags;
131 struct blk_trace *bt;
132
133 tsk->btrace_seq = blktrace_seq;
134 spin_lock_irqsave(&running_trace_lock, flags);
135 list_for_each_entry(bt, &running_trace_list, running_list) {
136 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
137 sizeof(tsk->comm), NULL);
138 }
139 spin_unlock_irqrestore(&running_trace_lock, flags);
140}
141
142static void trace_note_time(struct blk_trace *bt)
143{
144 struct timespec64 now;
145 unsigned long flags;
146 u32 words[2];
147
148 /* need to check user space to see if this breaks in y2038 or y2106 */
149 ktime_get_real_ts64(&now);
150 words[0] = (u32)now.tv_sec;
151 words[1] = now.tv_nsec;
152
153 local_irq_save(flags);
154 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), NULL);
155 local_irq_restore(flags);
156}
157
158void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
159 const char *fmt, ...)
160{
161 int n;
162 va_list args;
163 unsigned long flags;
164 char *buf;
165
166 if (unlikely(bt->trace_state != Blktrace_running &&
167 !blk_tracer_enabled))
168 return;
169
170 /*
171 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
172 * message to the trace.
173 */
174 if (!(bt->act_mask & BLK_TC_NOTIFY))
175 return;
176
177 local_irq_save(flags);
178 buf = this_cpu_ptr(bt->msg_data);
179 va_start(args, fmt);
180 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
181 va_end(args);
182
183 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
184 blkcg = NULL;
185#ifdef CONFIG_BLK_CGROUP
186 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n,
187 blkcg ? cgroup_get_kernfs_id(blkcg->css.cgroup) : NULL);
188#else
189 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL);
190#endif
191 local_irq_restore(flags);
192}
193EXPORT_SYMBOL_GPL(__trace_note_message);
194
195static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
196 pid_t pid)
197{
198 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
199 return 1;
200 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
201 return 1;
202 if (bt->pid && pid != bt->pid)
203 return 1;
204
205 return 0;
206}
207
208/*
209 * Data direction bit lookup
210 */
211static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
212 BLK_TC_ACT(BLK_TC_WRITE) };
213
214#define BLK_TC_RAHEAD BLK_TC_AHEAD
215#define BLK_TC_PREFLUSH BLK_TC_FLUSH
216
217/* The ilog2() calls fall out because they're constant */
218#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
219 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
220
221/*
222 * The worker for the various blk_add_trace*() types. Fills out a
223 * blk_io_trace structure and places it in a per-cpu subbuffer.
224 */
225static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
226 int op, int op_flags, u32 what, int error, int pdu_len,
227 void *pdu_data, union kernfs_node_id *cgid)
228{
229 struct task_struct *tsk = current;
230 struct ring_buffer_event *event = NULL;
231 struct ring_buffer *buffer = NULL;
232 struct blk_io_trace *t;
233 unsigned long flags = 0;
234 unsigned long *sequence;
235 pid_t pid;
236 int cpu, pc = 0;
237 bool blk_tracer = blk_tracer_enabled;
238 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
239
240 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
241 return;
242
243 what |= ddir_act[op_is_write(op) ? WRITE : READ];
244 what |= MASK_TC_BIT(op_flags, SYNC);
245 what |= MASK_TC_BIT(op_flags, RAHEAD);
246 what |= MASK_TC_BIT(op_flags, META);
247 what |= MASK_TC_BIT(op_flags, PREFLUSH);
248 what |= MASK_TC_BIT(op_flags, FUA);
249 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
250 what |= BLK_TC_ACT(BLK_TC_DISCARD);
251 if (op == REQ_OP_FLUSH)
252 what |= BLK_TC_ACT(BLK_TC_FLUSH);
253 if (cgid)
254 what |= __BLK_TA_CGROUP;
255
256 pid = tsk->pid;
257 if (act_log_check(bt, what, sector, pid))
258 return;
259 cpu = raw_smp_processor_id();
260
261 if (blk_tracer) {
262 tracing_record_cmdline(current);
263
264 buffer = blk_tr->trace_buffer.buffer;
265 pc = preempt_count();
266 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
267 sizeof(*t) + pdu_len + cgid_len,
268 0, pc);
269 if (!event)
270 return;
271 t = ring_buffer_event_data(event);
272 goto record_it;
273 }
274
275 if (unlikely(tsk->btrace_seq != blktrace_seq))
276 trace_note_tsk(tsk);
277
278 /*
279 * A word about the locking here - we disable interrupts to reserve
280 * some space in the relay per-cpu buffer, to prevent an irq
281 * from coming in and stepping on our toes.
282 */
283 local_irq_save(flags);
284 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
285 if (t) {
286 sequence = per_cpu_ptr(bt->sequence, cpu);
287
288 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
289 t->sequence = ++(*sequence);
290 t->time = ktime_to_ns(ktime_get());
291record_it:
292 /*
293 * These two are not needed in ftrace as they are in the
294 * generic trace_entry, filled by tracing_generic_entry_update,
295 * but for the trace_event->bin() synthesizer benefit we do it
296 * here too.
297 */
298 t->cpu = cpu;
299 t->pid = pid;
300
301 t->sector = sector;
302 t->bytes = bytes;
303 t->action = what;
304 t->device = bt->dev;
305 t->error = error;
306 t->pdu_len = pdu_len + cgid_len;
307
308 if (cgid_len)
309 memcpy((void *)t + sizeof(*t), cgid, cgid_len);
310 if (pdu_len)
311 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
312
313 if (blk_tracer) {
314 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
315 return;
316 }
317 }
318
319 local_irq_restore(flags);
320}
321
322static void blk_trace_free(struct blk_trace *bt)
323{
324 debugfs_remove(bt->msg_file);
325 debugfs_remove(bt->dropped_file);
326 relay_close(bt->rchan);
327 debugfs_remove(bt->dir);
328 free_percpu(bt->sequence);
329 free_percpu(bt->msg_data);
330 kfree(bt);
331}
332
333static void get_probe_ref(void)
334{
335 mutex_lock(&blk_probe_mutex);
336 if (++blk_probes_ref == 1)
337 blk_register_tracepoints();
338 mutex_unlock(&blk_probe_mutex);
339}
340
341static void put_probe_ref(void)
342{
343 mutex_lock(&blk_probe_mutex);
344 if (!--blk_probes_ref)
345 blk_unregister_tracepoints();
346 mutex_unlock(&blk_probe_mutex);
347}
348
349static void blk_trace_cleanup(struct blk_trace *bt)
350{
351 blk_trace_free(bt);
352 put_probe_ref();
353}
354
355static int __blk_trace_remove(struct request_queue *q)
356{
357 struct blk_trace *bt;
358
359 bt = xchg(&q->blk_trace, NULL);
360 if (!bt)
361 return -EINVAL;
362
363 if (bt->trace_state != Blktrace_running)
364 blk_trace_cleanup(bt);
365
366 return 0;
367}
368
369int blk_trace_remove(struct request_queue *q)
370{
371 int ret;
372
373 mutex_lock(&q->blk_trace_mutex);
374 ret = __blk_trace_remove(q);
375 mutex_unlock(&q->blk_trace_mutex);
376
377 return ret;
378}
379EXPORT_SYMBOL_GPL(blk_trace_remove);
380
381static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
382 size_t count, loff_t *ppos)
383{
384 struct blk_trace *bt = filp->private_data;
385 char buf[16];
386
387 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
388
389 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
390}
391
392static const struct file_operations blk_dropped_fops = {
393 .owner = THIS_MODULE,
394 .open = simple_open,
395 .read = blk_dropped_read,
396 .llseek = default_llseek,
397};
398
399static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
400 size_t count, loff_t *ppos)
401{
402 char *msg;
403 struct blk_trace *bt;
404
405 if (count >= BLK_TN_MAX_MSG)
406 return -EINVAL;
407
408 msg = memdup_user_nul(buffer, count);
409 if (IS_ERR(msg))
410 return PTR_ERR(msg);
411
412 bt = filp->private_data;
413 __trace_note_message(bt, NULL, "%s", msg);
414 kfree(msg);
415
416 return count;
417}
418
419static const struct file_operations blk_msg_fops = {
420 .owner = THIS_MODULE,
421 .open = simple_open,
422 .write = blk_msg_write,
423 .llseek = noop_llseek,
424};
425
426/*
427 * Keep track of how many times we encountered a full subbuffer, to aid
428 * the user space app in telling how many lost events there were.
429 */
430static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
431 void *prev_subbuf, size_t prev_padding)
432{
433 struct blk_trace *bt;
434
435 if (!relay_buf_full(buf))
436 return 1;
437
438 bt = buf->chan->private_data;
439 atomic_inc(&bt->dropped);
440 return 0;
441}
442
443static int blk_remove_buf_file_callback(struct dentry *dentry)
444{
445 debugfs_remove(dentry);
446
447 return 0;
448}
449
450static struct dentry *blk_create_buf_file_callback(const char *filename,
451 struct dentry *parent,
452 umode_t mode,
453 struct rchan_buf *buf,
454 int *is_global)
455{
456 return debugfs_create_file(filename, mode, parent, buf,
457 &relay_file_operations);
458}
459
460static struct rchan_callbacks blk_relay_callbacks = {
461 .subbuf_start = blk_subbuf_start_callback,
462 .create_buf_file = blk_create_buf_file_callback,
463 .remove_buf_file = blk_remove_buf_file_callback,
464};
465
466static void blk_trace_setup_lba(struct blk_trace *bt,
467 struct block_device *bdev)
468{
469 struct hd_struct *part = NULL;
470
471 if (bdev)
472 part = bdev->bd_part;
473
474 if (part) {
475 bt->start_lba = part->start_sect;
476 bt->end_lba = part->start_sect + part->nr_sects;
477 } else {
478 bt->start_lba = 0;
479 bt->end_lba = -1ULL;
480 }
481}
482
483/*
484 * Setup everything required to start tracing
485 */
486static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
487 struct block_device *bdev,
488 struct blk_user_trace_setup *buts)
489{
490 struct blk_trace *bt = NULL;
491 struct dentry *dir = NULL;
492 int ret;
493
494 if (!buts->buf_size || !buts->buf_nr)
495 return -EINVAL;
496
497 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
498 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
499
500 /*
501 * some device names have larger paths - convert the slashes
502 * to underscores for this to work as expected
503 */
504 strreplace(buts->name, '/', '_');
505
506 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
507 if (!bt)
508 return -ENOMEM;
509
510 ret = -ENOMEM;
511 bt->sequence = alloc_percpu(unsigned long);
512 if (!bt->sequence)
513 goto err;
514
515 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
516 if (!bt->msg_data)
517 goto err;
518
519 ret = -ENOENT;
520
521 if (!blk_debugfs_root)
522 goto err;
523
524 dir = debugfs_lookup(buts->name, blk_debugfs_root);
525 if (!dir)
526 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
527 if (!dir)
528 goto err;
529
530 bt->dev = dev;
531 atomic_set(&bt->dropped, 0);
532 INIT_LIST_HEAD(&bt->running_list);
533
534 ret = -EIO;
535 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
536 &blk_dropped_fops);
537 if (!bt->dropped_file)
538 goto err;
539
540 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
541 if (!bt->msg_file)
542 goto err;
543
544 bt->rchan = relay_open("trace", dir, buts->buf_size,
545 buts->buf_nr, &blk_relay_callbacks, bt);
546 if (!bt->rchan)
547 goto err;
548
549 bt->act_mask = buts->act_mask;
550 if (!bt->act_mask)
551 bt->act_mask = (u16) -1;
552
553 blk_trace_setup_lba(bt, bdev);
554
555 /* overwrite with user settings */
556 if (buts->start_lba)
557 bt->start_lba = buts->start_lba;
558 if (buts->end_lba)
559 bt->end_lba = buts->end_lba;
560
561 bt->pid = buts->pid;
562 bt->trace_state = Blktrace_setup;
563
564 ret = -EBUSY;
565 if (cmpxchg(&q->blk_trace, NULL, bt))
566 goto err;
567
568 get_probe_ref();
569
570 ret = 0;
571err:
572 if (dir && !bt->dir)
573 dput(dir);
574 if (ret)
575 blk_trace_free(bt);
576 return ret;
577}
578
579static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
580 struct block_device *bdev, char __user *arg)
581{
582 struct blk_user_trace_setup buts;
583 int ret;
584
585 ret = copy_from_user(&buts, arg, sizeof(buts));
586 if (ret)
587 return -EFAULT;
588
589 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
590 if (ret)
591 return ret;
592
593 if (copy_to_user(arg, &buts, sizeof(buts))) {
594 __blk_trace_remove(q);
595 return -EFAULT;
596 }
597 return 0;
598}
599
600int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
601 struct block_device *bdev,
602 char __user *arg)
603{
604 int ret;
605
606 mutex_lock(&q->blk_trace_mutex);
607 ret = __blk_trace_setup(q, name, dev, bdev, arg);
608 mutex_unlock(&q->blk_trace_mutex);
609
610 return ret;
611}
612EXPORT_SYMBOL_GPL(blk_trace_setup);
613
614#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
615static int compat_blk_trace_setup(struct request_queue *q, char *name,
616 dev_t dev, struct block_device *bdev,
617 char __user *arg)
618{
619 struct blk_user_trace_setup buts;
620 struct compat_blk_user_trace_setup cbuts;
621 int ret;
622
623 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
624 return -EFAULT;
625
626 buts = (struct blk_user_trace_setup) {
627 .act_mask = cbuts.act_mask,
628 .buf_size = cbuts.buf_size,
629 .buf_nr = cbuts.buf_nr,
630 .start_lba = cbuts.start_lba,
631 .end_lba = cbuts.end_lba,
632 .pid = cbuts.pid,
633 };
634
635 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
636 if (ret)
637 return ret;
638
639 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
640 __blk_trace_remove(q);
641 return -EFAULT;
642 }
643
644 return 0;
645}
646#endif
647
648static int __blk_trace_startstop(struct request_queue *q, int start)
649{
650 int ret;
651 struct blk_trace *bt = q->blk_trace;
652
653 if (bt == NULL)
654 return -EINVAL;
655
656 /*
657 * For starting a trace, we can transition from a setup or stopped
658 * trace. For stopping a trace, the state must be running
659 */
660 ret = -EINVAL;
661 if (start) {
662 if (bt->trace_state == Blktrace_setup ||
663 bt->trace_state == Blktrace_stopped) {
664 blktrace_seq++;
665 smp_mb();
666 bt->trace_state = Blktrace_running;
667 spin_lock_irq(&running_trace_lock);
668 list_add(&bt->running_list, &running_trace_list);
669 spin_unlock_irq(&running_trace_lock);
670
671 trace_note_time(bt);
672 ret = 0;
673 }
674 } else {
675 if (bt->trace_state == Blktrace_running) {
676 bt->trace_state = Blktrace_stopped;
677 spin_lock_irq(&running_trace_lock);
678 list_del_init(&bt->running_list);
679 spin_unlock_irq(&running_trace_lock);
680 relay_flush(bt->rchan);
681 ret = 0;
682 }
683 }
684
685 return ret;
686}
687
688int blk_trace_startstop(struct request_queue *q, int start)
689{
690 int ret;
691
692 mutex_lock(&q->blk_trace_mutex);
693 ret = __blk_trace_startstop(q, start);
694 mutex_unlock(&q->blk_trace_mutex);
695
696 return ret;
697}
698EXPORT_SYMBOL_GPL(blk_trace_startstop);
699
700/*
701 * When reading or writing the blktrace sysfs files, the references to the
702 * opened sysfs or device files should prevent the underlying block device
703 * from being removed. So no further delete protection is really needed.
704 */
705
706/**
707 * blk_trace_ioctl: - handle the ioctls associated with tracing
708 * @bdev: the block device
709 * @cmd: the ioctl cmd
710 * @arg: the argument data, if any
711 *
712 **/
713int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
714{
715 struct request_queue *q;
716 int ret, start = 0;
717 char b[BDEVNAME_SIZE];
718
719 q = bdev_get_queue(bdev);
720 if (!q)
721 return -ENXIO;
722
723 mutex_lock(&q->blk_trace_mutex);
724
725 switch (cmd) {
726 case BLKTRACESETUP:
727 bdevname(bdev, b);
728 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
729 break;
730#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
731 case BLKTRACESETUP32:
732 bdevname(bdev, b);
733 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
734 break;
735#endif
736 case BLKTRACESTART:
737 start = 1;
738 case BLKTRACESTOP:
739 ret = __blk_trace_startstop(q, start);
740 break;
741 case BLKTRACETEARDOWN:
742 ret = __blk_trace_remove(q);
743 break;
744 default:
745 ret = -ENOTTY;
746 break;
747 }
748
749 mutex_unlock(&q->blk_trace_mutex);
750 return ret;
751}
752
753/**
754 * blk_trace_shutdown: - stop and cleanup trace structures
755 * @q: the request queue associated with the device
756 *
757 **/
758void blk_trace_shutdown(struct request_queue *q)
759{
760 mutex_lock(&q->blk_trace_mutex);
761
762 if (q->blk_trace) {
763 __blk_trace_startstop(q, 0);
764 __blk_trace_remove(q);
765 }
766
767 mutex_unlock(&q->blk_trace_mutex);
768}
769
770#ifdef CONFIG_BLK_CGROUP
771static union kernfs_node_id *
772blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
773{
774 struct blk_trace *bt = q->blk_trace;
775
776 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
777 return NULL;
778
779 if (!bio->bi_css)
780 return NULL;
781 return cgroup_get_kernfs_id(bio->bi_css->cgroup);
782}
783#else
784static union kernfs_node_id *
785blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
786{
787 return NULL;
788}
789#endif
790
791static union kernfs_node_id *
792blk_trace_request_get_cgid(struct request_queue *q, struct request *rq)
793{
794 if (!rq->bio)
795 return NULL;
796 /* Use the first bio */
797 return blk_trace_bio_get_cgid(q, rq->bio);
798}
799
800/*
801 * blktrace probes
802 */
803
804/**
805 * blk_add_trace_rq - Add a trace for a request oriented action
806 * @rq: the source request
807 * @error: return status to log
808 * @nr_bytes: number of completed bytes
809 * @what: the action
810 * @cgid: the cgroup info
811 *
812 * Description:
813 * Records an action against a request. Will log the bio offset + size.
814 *
815 **/
816static void blk_add_trace_rq(struct request *rq, int error,
817 unsigned int nr_bytes, u32 what,
818 union kernfs_node_id *cgid)
819{
820 struct blk_trace *bt = rq->q->blk_trace;
821
822 if (likely(!bt))
823 return;
824
825 if (blk_rq_is_passthrough(rq))
826 what |= BLK_TC_ACT(BLK_TC_PC);
827 else
828 what |= BLK_TC_ACT(BLK_TC_FS);
829
830 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
831 rq->cmd_flags, what, error, 0, NULL, cgid);
832}
833
834static void blk_add_trace_rq_insert(void *ignore,
835 struct request_queue *q, struct request *rq)
836{
837 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
838 blk_trace_request_get_cgid(q, rq));
839}
840
841static void blk_add_trace_rq_issue(void *ignore,
842 struct request_queue *q, struct request *rq)
843{
844 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
845 blk_trace_request_get_cgid(q, rq));
846}
847
848static void blk_add_trace_rq_requeue(void *ignore,
849 struct request_queue *q,
850 struct request *rq)
851{
852 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
853 blk_trace_request_get_cgid(q, rq));
854}
855
856static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
857 int error, unsigned int nr_bytes)
858{
859 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
860 blk_trace_request_get_cgid(rq->q, rq));
861}
862
863/**
864 * blk_add_trace_bio - Add a trace for a bio oriented action
865 * @q: queue the io is for
866 * @bio: the source bio
867 * @what: the action
868 * @error: error, if any
869 *
870 * Description:
871 * Records an action against a bio. Will log the bio offset + size.
872 *
873 **/
874static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
875 u32 what, int error)
876{
877 struct blk_trace *bt = q->blk_trace;
878
879 if (likely(!bt))
880 return;
881
882 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
883 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
884 blk_trace_bio_get_cgid(q, bio));
885}
886
887static void blk_add_trace_bio_bounce(void *ignore,
888 struct request_queue *q, struct bio *bio)
889{
890 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
891}
892
893static void blk_add_trace_bio_complete(void *ignore,
894 struct request_queue *q, struct bio *bio,
895 int error)
896{
897 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
898}
899
900static void blk_add_trace_bio_backmerge(void *ignore,
901 struct request_queue *q,
902 struct request *rq,
903 struct bio *bio)
904{
905 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
906}
907
908static void blk_add_trace_bio_frontmerge(void *ignore,
909 struct request_queue *q,
910 struct request *rq,
911 struct bio *bio)
912{
913 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
914}
915
916static void blk_add_trace_bio_queue(void *ignore,
917 struct request_queue *q, struct bio *bio)
918{
919 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
920}
921
922static void blk_add_trace_getrq(void *ignore,
923 struct request_queue *q,
924 struct bio *bio, int rw)
925{
926 if (bio)
927 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
928 else {
929 struct blk_trace *bt = q->blk_trace;
930
931 if (bt)
932 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
933 NULL, NULL);
934 }
935}
936
937
938static void blk_add_trace_sleeprq(void *ignore,
939 struct request_queue *q,
940 struct bio *bio, int rw)
941{
942 if (bio)
943 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
944 else {
945 struct blk_trace *bt = q->blk_trace;
946
947 if (bt)
948 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
949 0, 0, NULL, NULL);
950 }
951}
952
953static void blk_add_trace_plug(void *ignore, struct request_queue *q)
954{
955 struct blk_trace *bt = q->blk_trace;
956
957 if (bt)
958 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, NULL);
959}
960
961static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
962 unsigned int depth, bool explicit)
963{
964 struct blk_trace *bt = q->blk_trace;
965
966 if (bt) {
967 __be64 rpdu = cpu_to_be64(depth);
968 u32 what;
969
970 if (explicit)
971 what = BLK_TA_UNPLUG_IO;
972 else
973 what = BLK_TA_UNPLUG_TIMER;
974
975 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, NULL);
976 }
977}
978
979static void blk_add_trace_split(void *ignore,
980 struct request_queue *q, struct bio *bio,
981 unsigned int pdu)
982{
983 struct blk_trace *bt = q->blk_trace;
984
985 if (bt) {
986 __be64 rpdu = cpu_to_be64(pdu);
987
988 __blk_add_trace(bt, bio->bi_iter.bi_sector,
989 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
990 BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu),
991 &rpdu, blk_trace_bio_get_cgid(q, bio));
992 }
993}
994
995/**
996 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
997 * @ignore: trace callback data parameter (not used)
998 * @q: queue the io is for
999 * @bio: the source bio
1000 * @dev: target device
1001 * @from: source sector
1002 *
1003 * Description:
1004 * Device mapper or raid target sometimes need to split a bio because
1005 * it spans a stripe (or similar). Add a trace for that action.
1006 *
1007 **/
1008static void blk_add_trace_bio_remap(void *ignore,
1009 struct request_queue *q, struct bio *bio,
1010 dev_t dev, sector_t from)
1011{
1012 struct blk_trace *bt = q->blk_trace;
1013 struct blk_io_trace_remap r;
1014
1015 if (likely(!bt))
1016 return;
1017
1018 r.device_from = cpu_to_be32(dev);
1019 r.device_to = cpu_to_be32(bio_dev(bio));
1020 r.sector_from = cpu_to_be64(from);
1021
1022 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1023 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status,
1024 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1025}
1026
1027/**
1028 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1029 * @ignore: trace callback data parameter (not used)
1030 * @q: queue the io is for
1031 * @rq: the source request
1032 * @dev: target device
1033 * @from: source sector
1034 *
1035 * Description:
1036 * Device mapper remaps request to other devices.
1037 * Add a trace for that action.
1038 *
1039 **/
1040static void blk_add_trace_rq_remap(void *ignore,
1041 struct request_queue *q,
1042 struct request *rq, dev_t dev,
1043 sector_t from)
1044{
1045 struct blk_trace *bt = q->blk_trace;
1046 struct blk_io_trace_remap r;
1047
1048 if (likely(!bt))
1049 return;
1050
1051 r.device_from = cpu_to_be32(dev);
1052 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1053 r.sector_from = cpu_to_be64(from);
1054
1055 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1056 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1057 sizeof(r), &r, blk_trace_request_get_cgid(q, rq));
1058}
1059
1060/**
1061 * blk_add_driver_data - Add binary message with driver-specific data
1062 * @q: queue the io is for
1063 * @rq: io request
1064 * @data: driver-specific data
1065 * @len: length of driver-specific data
1066 *
1067 * Description:
1068 * Some drivers might want to write driver-specific data per request.
1069 *
1070 **/
1071void blk_add_driver_data(struct request_queue *q,
1072 struct request *rq,
1073 void *data, size_t len)
1074{
1075 struct blk_trace *bt = q->blk_trace;
1076
1077 if (likely(!bt))
1078 return;
1079
1080 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1081 BLK_TA_DRV_DATA, 0, len, data,
1082 blk_trace_request_get_cgid(q, rq));
1083}
1084EXPORT_SYMBOL_GPL(blk_add_driver_data);
1085
1086static void blk_register_tracepoints(void)
1087{
1088 int ret;
1089
1090 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1091 WARN_ON(ret);
1092 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1093 WARN_ON(ret);
1094 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1095 WARN_ON(ret);
1096 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1097 WARN_ON(ret);
1098 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1099 WARN_ON(ret);
1100 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1101 WARN_ON(ret);
1102 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1103 WARN_ON(ret);
1104 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1105 WARN_ON(ret);
1106 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1107 WARN_ON(ret);
1108 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1109 WARN_ON(ret);
1110 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1111 WARN_ON(ret);
1112 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1113 WARN_ON(ret);
1114 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1115 WARN_ON(ret);
1116 ret = register_trace_block_split(blk_add_trace_split, NULL);
1117 WARN_ON(ret);
1118 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1119 WARN_ON(ret);
1120 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1121 WARN_ON(ret);
1122}
1123
1124static void blk_unregister_tracepoints(void)
1125{
1126 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1127 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1128 unregister_trace_block_split(blk_add_trace_split, NULL);
1129 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1130 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1131 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1132 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1133 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1134 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1135 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1136 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1137 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1138 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1139 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1140 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1141 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1142
1143 tracepoint_synchronize_unregister();
1144}
1145
1146/*
1147 * struct blk_io_tracer formatting routines
1148 */
1149
1150static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1151{
1152 int i = 0;
1153 int tc = t->action >> BLK_TC_SHIFT;
1154
1155 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1156 rwbs[i++] = 'N';
1157 goto out;
1158 }
1159
1160 if (tc & BLK_TC_FLUSH)
1161 rwbs[i++] = 'F';
1162
1163 if (tc & BLK_TC_DISCARD)
1164 rwbs[i++] = 'D';
1165 else if (tc & BLK_TC_WRITE)
1166 rwbs[i++] = 'W';
1167 else if (t->bytes)
1168 rwbs[i++] = 'R';
1169 else
1170 rwbs[i++] = 'N';
1171
1172 if (tc & BLK_TC_FUA)
1173 rwbs[i++] = 'F';
1174 if (tc & BLK_TC_AHEAD)
1175 rwbs[i++] = 'A';
1176 if (tc & BLK_TC_SYNC)
1177 rwbs[i++] = 'S';
1178 if (tc & BLK_TC_META)
1179 rwbs[i++] = 'M';
1180out:
1181 rwbs[i] = '\0';
1182}
1183
1184static inline
1185const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1186{
1187 return (const struct blk_io_trace *)ent;
1188}
1189
1190static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1191{
1192 return (void *)(te_blk_io_trace(ent) + 1) +
1193 (has_cg ? sizeof(union kernfs_node_id) : 0);
1194}
1195
1196static inline const void *cgid_start(const struct trace_entry *ent)
1197{
1198 return (void *)(te_blk_io_trace(ent) + 1);
1199}
1200
1201static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1202{
1203 return te_blk_io_trace(ent)->pdu_len -
1204 (has_cg ? sizeof(union kernfs_node_id) : 0);
1205}
1206
1207static inline u32 t_action(const struct trace_entry *ent)
1208{
1209 return te_blk_io_trace(ent)->action;
1210}
1211
1212static inline u32 t_bytes(const struct trace_entry *ent)
1213{
1214 return te_blk_io_trace(ent)->bytes;
1215}
1216
1217static inline u32 t_sec(const struct trace_entry *ent)
1218{
1219 return te_blk_io_trace(ent)->bytes >> 9;
1220}
1221
1222static inline unsigned long long t_sector(const struct trace_entry *ent)
1223{
1224 return te_blk_io_trace(ent)->sector;
1225}
1226
1227static inline __u16 t_error(const struct trace_entry *ent)
1228{
1229 return te_blk_io_trace(ent)->error;
1230}
1231
1232static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1233{
1234 const __u64 *val = pdu_start(ent, has_cg);
1235 return be64_to_cpu(*val);
1236}
1237
1238static void get_pdu_remap(const struct trace_entry *ent,
1239 struct blk_io_trace_remap *r, bool has_cg)
1240{
1241 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1242 __u64 sector_from = __r->sector_from;
1243
1244 r->device_from = be32_to_cpu(__r->device_from);
1245 r->device_to = be32_to_cpu(__r->device_to);
1246 r->sector_from = be64_to_cpu(sector_from);
1247}
1248
1249typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1250 bool has_cg);
1251
1252static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1253 bool has_cg)
1254{
1255 char rwbs[RWBS_LEN];
1256 unsigned long long ts = iter->ts;
1257 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1258 unsigned secs = (unsigned long)ts;
1259 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1260
1261 fill_rwbs(rwbs, t);
1262
1263 trace_seq_printf(&iter->seq,
1264 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1265 MAJOR(t->device), MINOR(t->device), iter->cpu,
1266 secs, nsec_rem, iter->ent->pid, act, rwbs);
1267}
1268
1269static void blk_log_action(struct trace_iterator *iter, const char *act,
1270 bool has_cg)
1271{
1272 char rwbs[RWBS_LEN];
1273 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1274
1275 fill_rwbs(rwbs, t);
1276 if (has_cg) {
1277 const union kernfs_node_id *id = cgid_start(iter->ent);
1278
1279 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1280 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1281
1282 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1283 sizeof(blkcg_name_buf));
1284 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1285 MAJOR(t->device), MINOR(t->device),
1286 blkcg_name_buf, act, rwbs);
1287 } else
1288 trace_seq_printf(&iter->seq,
1289 "%3d,%-3d %x,%-x %2s %3s ",
1290 MAJOR(t->device), MINOR(t->device),
1291 id->ino, id->generation, act, rwbs);
1292 } else
1293 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1294 MAJOR(t->device), MINOR(t->device), act, rwbs);
1295}
1296
1297static void blk_log_dump_pdu(struct trace_seq *s,
1298 const struct trace_entry *ent, bool has_cg)
1299{
1300 const unsigned char *pdu_buf;
1301 int pdu_len;
1302 int i, end;
1303
1304 pdu_buf = pdu_start(ent, has_cg);
1305 pdu_len = pdu_real_len(ent, has_cg);
1306
1307 if (!pdu_len)
1308 return;
1309
1310 /* find the last zero that needs to be printed */
1311 for (end = pdu_len - 1; end >= 0; end--)
1312 if (pdu_buf[end])
1313 break;
1314 end++;
1315
1316 trace_seq_putc(s, '(');
1317
1318 for (i = 0; i < pdu_len; i++) {
1319
1320 trace_seq_printf(s, "%s%02x",
1321 i == 0 ? "" : " ", pdu_buf[i]);
1322
1323 /*
1324 * stop when the rest is just zeroes and indicate so
1325 * with a ".." appended
1326 */
1327 if (i == end && end != pdu_len - 1) {
1328 trace_seq_puts(s, " ..) ");
1329 return;
1330 }
1331 }
1332
1333 trace_seq_puts(s, ") ");
1334}
1335
1336static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1337{
1338 char cmd[TASK_COMM_LEN];
1339
1340 trace_find_cmdline(ent->pid, cmd);
1341
1342 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1343 trace_seq_printf(s, "%u ", t_bytes(ent));
1344 blk_log_dump_pdu(s, ent, has_cg);
1345 trace_seq_printf(s, "[%s]\n", cmd);
1346 } else {
1347 if (t_sec(ent))
1348 trace_seq_printf(s, "%llu + %u [%s]\n",
1349 t_sector(ent), t_sec(ent), cmd);
1350 else
1351 trace_seq_printf(s, "[%s]\n", cmd);
1352 }
1353}
1354
1355static void blk_log_with_error(struct trace_seq *s,
1356 const struct trace_entry *ent, bool has_cg)
1357{
1358 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1359 blk_log_dump_pdu(s, ent, has_cg);
1360 trace_seq_printf(s, "[%d]\n", t_error(ent));
1361 } else {
1362 if (t_sec(ent))
1363 trace_seq_printf(s, "%llu + %u [%d]\n",
1364 t_sector(ent),
1365 t_sec(ent), t_error(ent));
1366 else
1367 trace_seq_printf(s, "%llu [%d]\n",
1368 t_sector(ent), t_error(ent));
1369 }
1370}
1371
1372static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1373{
1374 struct blk_io_trace_remap r = { .device_from = 0, };
1375
1376 get_pdu_remap(ent, &r, has_cg);
1377 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1378 t_sector(ent), t_sec(ent),
1379 MAJOR(r.device_from), MINOR(r.device_from),
1380 (unsigned long long)r.sector_from);
1381}
1382
1383static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1384{
1385 char cmd[TASK_COMM_LEN];
1386
1387 trace_find_cmdline(ent->pid, cmd);
1388
1389 trace_seq_printf(s, "[%s]\n", cmd);
1390}
1391
1392static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1393{
1394 char cmd[TASK_COMM_LEN];
1395
1396 trace_find_cmdline(ent->pid, cmd);
1397
1398 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1399}
1400
1401static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1402{
1403 char cmd[TASK_COMM_LEN];
1404
1405 trace_find_cmdline(ent->pid, cmd);
1406
1407 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1408 get_pdu_int(ent, has_cg), cmd);
1409}
1410
1411static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1412 bool has_cg)
1413{
1414
1415 trace_seq_putmem(s, pdu_start(ent, has_cg),
1416 pdu_real_len(ent, has_cg));
1417 trace_seq_putc(s, '\n');
1418}
1419
1420/*
1421 * struct tracer operations
1422 */
1423
1424static void blk_tracer_print_header(struct seq_file *m)
1425{
1426 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1427 return;
1428 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1429 "# | | | | | |\n");
1430}
1431
1432static void blk_tracer_start(struct trace_array *tr)
1433{
1434 blk_tracer_enabled = true;
1435}
1436
1437static int blk_tracer_init(struct trace_array *tr)
1438{
1439 blk_tr = tr;
1440 blk_tracer_start(tr);
1441 return 0;
1442}
1443
1444static void blk_tracer_stop(struct trace_array *tr)
1445{
1446 blk_tracer_enabled = false;
1447}
1448
1449static void blk_tracer_reset(struct trace_array *tr)
1450{
1451 blk_tracer_stop(tr);
1452}
1453
1454static const struct {
1455 const char *act[2];
1456 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1457 bool has_cg);
1458} what2act[] = {
1459 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1460 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1461 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1462 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1463 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1464 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1465 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1466 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1467 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1468 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1469 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1470 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1471 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1472 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1473 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1474};
1475
1476static enum print_line_t print_one_line(struct trace_iterator *iter,
1477 bool classic)
1478{
1479 struct trace_array *tr = iter->tr;
1480 struct trace_seq *s = &iter->seq;
1481 const struct blk_io_trace *t;
1482 u16 what;
1483 bool long_act;
1484 blk_log_action_t *log_action;
1485 bool has_cg;
1486
1487 t = te_blk_io_trace(iter->ent);
1488 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1489 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1490 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1491 has_cg = t->action & __BLK_TA_CGROUP;
1492
1493 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1494 log_action(iter, long_act ? "message" : "m", has_cg);
1495 blk_log_msg(s, iter->ent, has_cg);
1496 return trace_handle_return(s);
1497 }
1498
1499 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1500 trace_seq_printf(s, "Unknown action %x\n", what);
1501 else {
1502 log_action(iter, what2act[what].act[long_act], has_cg);
1503 what2act[what].print(s, iter->ent, has_cg);
1504 }
1505
1506 return trace_handle_return(s);
1507}
1508
1509static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1510 int flags, struct trace_event *event)
1511{
1512 return print_one_line(iter, false);
1513}
1514
1515static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1516{
1517 struct trace_seq *s = &iter->seq;
1518 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1519 const int offset = offsetof(struct blk_io_trace, sector);
1520 struct blk_io_trace old = {
1521 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1522 .time = iter->ts,
1523 };
1524
1525 trace_seq_putmem(s, &old, offset);
1526 trace_seq_putmem(s, &t->sector,
1527 sizeof(old) - offset + t->pdu_len);
1528}
1529
1530static enum print_line_t
1531blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1532 struct trace_event *event)
1533{
1534 blk_trace_synthesize_old_trace(iter);
1535
1536 return trace_handle_return(&iter->seq);
1537}
1538
1539static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1540{
1541 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1542 return TRACE_TYPE_UNHANDLED;
1543
1544 return print_one_line(iter, true);
1545}
1546
1547static int
1548blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1549{
1550 /* don't output context-info for blk_classic output */
1551 if (bit == TRACE_BLK_OPT_CLASSIC) {
1552 if (set)
1553 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1554 else
1555 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1556 }
1557 return 0;
1558}
1559
1560static struct tracer blk_tracer __read_mostly = {
1561 .name = "blk",
1562 .init = blk_tracer_init,
1563 .reset = blk_tracer_reset,
1564 .start = blk_tracer_start,
1565 .stop = blk_tracer_stop,
1566 .print_header = blk_tracer_print_header,
1567 .print_line = blk_tracer_print_line,
1568 .flags = &blk_tracer_flags,
1569 .set_flag = blk_tracer_set_flag,
1570};
1571
1572static struct trace_event_functions trace_blk_event_funcs = {
1573 .trace = blk_trace_event_print,
1574 .binary = blk_trace_event_print_binary,
1575};
1576
1577static struct trace_event trace_blk_event = {
1578 .type = TRACE_BLK,
1579 .funcs = &trace_blk_event_funcs,
1580};
1581
1582static int __init init_blk_tracer(void)
1583{
1584 if (!register_trace_event(&trace_blk_event)) {
1585 pr_warn("Warning: could not register block events\n");
1586 return 1;
1587 }
1588
1589 if (register_tracer(&blk_tracer) != 0) {
1590 pr_warn("Warning: could not register the block tracer\n");
1591 unregister_trace_event(&trace_blk_event);
1592 return 1;
1593 }
1594
1595 return 0;
1596}
1597
1598device_initcall(init_blk_tracer);
1599
1600static int blk_trace_remove_queue(struct request_queue *q)
1601{
1602 struct blk_trace *bt;
1603
1604 bt = xchg(&q->blk_trace, NULL);
1605 if (bt == NULL)
1606 return -EINVAL;
1607
1608 put_probe_ref();
1609 blk_trace_free(bt);
1610 return 0;
1611}
1612
1613/*
1614 * Setup everything required to start tracing
1615 */
1616static int blk_trace_setup_queue(struct request_queue *q,
1617 struct block_device *bdev)
1618{
1619 struct blk_trace *bt = NULL;
1620 int ret = -ENOMEM;
1621
1622 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1623 if (!bt)
1624 return -ENOMEM;
1625
1626 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1627 if (!bt->msg_data)
1628 goto free_bt;
1629
1630 bt->dev = bdev->bd_dev;
1631 bt->act_mask = (u16)-1;
1632
1633 blk_trace_setup_lba(bt, bdev);
1634
1635 ret = -EBUSY;
1636 if (cmpxchg(&q->blk_trace, NULL, bt))
1637 goto free_bt;
1638
1639 get_probe_ref();
1640 return 0;
1641
1642free_bt:
1643 blk_trace_free(bt);
1644 return ret;
1645}
1646
1647/*
1648 * sysfs interface to enable and configure tracing
1649 */
1650
1651static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1652 struct device_attribute *attr,
1653 char *buf);
1654static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1655 struct device_attribute *attr,
1656 const char *buf, size_t count);
1657#define BLK_TRACE_DEVICE_ATTR(_name) \
1658 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1659 sysfs_blk_trace_attr_show, \
1660 sysfs_blk_trace_attr_store)
1661
1662static BLK_TRACE_DEVICE_ATTR(enable);
1663static BLK_TRACE_DEVICE_ATTR(act_mask);
1664static BLK_TRACE_DEVICE_ATTR(pid);
1665static BLK_TRACE_DEVICE_ATTR(start_lba);
1666static BLK_TRACE_DEVICE_ATTR(end_lba);
1667
1668static struct attribute *blk_trace_attrs[] = {
1669 &dev_attr_enable.attr,
1670 &dev_attr_act_mask.attr,
1671 &dev_attr_pid.attr,
1672 &dev_attr_start_lba.attr,
1673 &dev_attr_end_lba.attr,
1674 NULL
1675};
1676
1677struct attribute_group blk_trace_attr_group = {
1678 .name = "trace",
1679 .attrs = blk_trace_attrs,
1680};
1681
1682static const struct {
1683 int mask;
1684 const char *str;
1685} mask_maps[] = {
1686 { BLK_TC_READ, "read" },
1687 { BLK_TC_WRITE, "write" },
1688 { BLK_TC_FLUSH, "flush" },
1689 { BLK_TC_SYNC, "sync" },
1690 { BLK_TC_QUEUE, "queue" },
1691 { BLK_TC_REQUEUE, "requeue" },
1692 { BLK_TC_ISSUE, "issue" },
1693 { BLK_TC_COMPLETE, "complete" },
1694 { BLK_TC_FS, "fs" },
1695 { BLK_TC_PC, "pc" },
1696 { BLK_TC_NOTIFY, "notify" },
1697 { BLK_TC_AHEAD, "ahead" },
1698 { BLK_TC_META, "meta" },
1699 { BLK_TC_DISCARD, "discard" },
1700 { BLK_TC_DRV_DATA, "drv_data" },
1701 { BLK_TC_FUA, "fua" },
1702};
1703
1704static int blk_trace_str2mask(const char *str)
1705{
1706 int i;
1707 int mask = 0;
1708 char *buf, *s, *token;
1709
1710 buf = kstrdup(str, GFP_KERNEL);
1711 if (buf == NULL)
1712 return -ENOMEM;
1713 s = strstrip(buf);
1714
1715 while (1) {
1716 token = strsep(&s, ",");
1717 if (token == NULL)
1718 break;
1719
1720 if (*token == '\0')
1721 continue;
1722
1723 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1724 if (strcasecmp(token, mask_maps[i].str) == 0) {
1725 mask |= mask_maps[i].mask;
1726 break;
1727 }
1728 }
1729 if (i == ARRAY_SIZE(mask_maps)) {
1730 mask = -EINVAL;
1731 break;
1732 }
1733 }
1734 kfree(buf);
1735
1736 return mask;
1737}
1738
1739static ssize_t blk_trace_mask2str(char *buf, int mask)
1740{
1741 int i;
1742 char *p = buf;
1743
1744 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1745 if (mask & mask_maps[i].mask) {
1746 p += sprintf(p, "%s%s",
1747 (p == buf) ? "" : ",", mask_maps[i].str);
1748 }
1749 }
1750 *p++ = '\n';
1751
1752 return p - buf;
1753}
1754
1755static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1756{
1757 if (bdev->bd_disk == NULL)
1758 return NULL;
1759
1760 return bdev_get_queue(bdev);
1761}
1762
1763static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1764 struct device_attribute *attr,
1765 char *buf)
1766{
1767 struct hd_struct *p = dev_to_part(dev);
1768 struct request_queue *q;
1769 struct block_device *bdev;
1770 ssize_t ret = -ENXIO;
1771
1772 bdev = bdget(part_devt(p));
1773 if (bdev == NULL)
1774 goto out;
1775
1776 q = blk_trace_get_queue(bdev);
1777 if (q == NULL)
1778 goto out_bdput;
1779
1780 mutex_lock(&q->blk_trace_mutex);
1781
1782 if (attr == &dev_attr_enable) {
1783 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1784 goto out_unlock_bdev;
1785 }
1786
1787 if (q->blk_trace == NULL)
1788 ret = sprintf(buf, "disabled\n");
1789 else if (attr == &dev_attr_act_mask)
1790 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1791 else if (attr == &dev_attr_pid)
1792 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1793 else if (attr == &dev_attr_start_lba)
1794 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1795 else if (attr == &dev_attr_end_lba)
1796 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1797
1798out_unlock_bdev:
1799 mutex_unlock(&q->blk_trace_mutex);
1800out_bdput:
1801 bdput(bdev);
1802out:
1803 return ret;
1804}
1805
1806static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1807 struct device_attribute *attr,
1808 const char *buf, size_t count)
1809{
1810 struct block_device *bdev;
1811 struct request_queue *q;
1812 struct hd_struct *p;
1813 u64 value;
1814 ssize_t ret = -EINVAL;
1815
1816 if (count == 0)
1817 goto out;
1818
1819 if (attr == &dev_attr_act_mask) {
1820 if (kstrtoull(buf, 0, &value)) {
1821 /* Assume it is a list of trace category names */
1822 ret = blk_trace_str2mask(buf);
1823 if (ret < 0)
1824 goto out;
1825 value = ret;
1826 }
1827 } else if (kstrtoull(buf, 0, &value))
1828 goto out;
1829
1830 ret = -ENXIO;
1831
1832 p = dev_to_part(dev);
1833 bdev = bdget(part_devt(p));
1834 if (bdev == NULL)
1835 goto out;
1836
1837 q = blk_trace_get_queue(bdev);
1838 if (q == NULL)
1839 goto out_bdput;
1840
1841 mutex_lock(&q->blk_trace_mutex);
1842
1843 if (attr == &dev_attr_enable) {
1844 if (value)
1845 ret = blk_trace_setup_queue(q, bdev);
1846 else
1847 ret = blk_trace_remove_queue(q);
1848 goto out_unlock_bdev;
1849 }
1850
1851 ret = 0;
1852 if (q->blk_trace == NULL)
1853 ret = blk_trace_setup_queue(q, bdev);
1854
1855 if (ret == 0) {
1856 if (attr == &dev_attr_act_mask)
1857 q->blk_trace->act_mask = value;
1858 else if (attr == &dev_attr_pid)
1859 q->blk_trace->pid = value;
1860 else if (attr == &dev_attr_start_lba)
1861 q->blk_trace->start_lba = value;
1862 else if (attr == &dev_attr_end_lba)
1863 q->blk_trace->end_lba = value;
1864 }
1865
1866out_unlock_bdev:
1867 mutex_unlock(&q->blk_trace_mutex);
1868out_bdput:
1869 bdput(bdev);
1870out:
1871 return ret ? ret : count;
1872}
1873
1874int blk_trace_init_sysfs(struct device *dev)
1875{
1876 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1877}
1878
1879void blk_trace_remove_sysfs(struct device *dev)
1880{
1881 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1882}
1883
1884#endif /* CONFIG_BLK_DEV_IO_TRACE */
1885
1886#ifdef CONFIG_EVENT_TRACING
1887
1888void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
1889{
1890 int i = 0;
1891
1892 if (op & REQ_PREFLUSH)
1893 rwbs[i++] = 'F';
1894
1895 switch (op & REQ_OP_MASK) {
1896 case REQ_OP_WRITE:
1897 case REQ_OP_WRITE_SAME:
1898 rwbs[i++] = 'W';
1899 break;
1900 case REQ_OP_DISCARD:
1901 rwbs[i++] = 'D';
1902 break;
1903 case REQ_OP_SECURE_ERASE:
1904 rwbs[i++] = 'D';
1905 rwbs[i++] = 'E';
1906 break;
1907 case REQ_OP_FLUSH:
1908 rwbs[i++] = 'F';
1909 break;
1910 case REQ_OP_READ:
1911 rwbs[i++] = 'R';
1912 break;
1913 default:
1914 rwbs[i++] = 'N';
1915 }
1916
1917 if (op & REQ_FUA)
1918 rwbs[i++] = 'F';
1919 if (op & REQ_RAHEAD)
1920 rwbs[i++] = 'A';
1921 if (op & REQ_SYNC)
1922 rwbs[i++] = 'S';
1923 if (op & REQ_META)
1924 rwbs[i++] = 'M';
1925
1926 rwbs[i] = '\0';
1927}
1928EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1929
1930#endif /* CONFIG_EVENT_TRACING */
1931