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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
4 *
5 */
6#include <linux/kernel.h>
7#include <linux/blkdev.h>
8#include <linux/blktrace_api.h>
9#include <linux/percpu.h>
10#include <linux/init.h>
11#include <linux/mutex.h>
12#include <linux/slab.h>
13#include <linux/debugfs.h>
14#include <linux/export.h>
15#include <linux/time.h>
16#include <linux/uaccess.h>
17#include <linux/list.h>
18#include <linux/blk-cgroup.h>
19
20#include "../../block/blk.h"
21
22#include <trace/events/block.h>
23
24#include "trace_output.h"
25
26#ifdef CONFIG_BLK_DEV_IO_TRACE
27
28static unsigned int blktrace_seq __read_mostly = 1;
29
30static struct trace_array *blk_tr;
31static bool blk_tracer_enabled __read_mostly;
32
33static LIST_HEAD(running_trace_list);
34static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
35
36/* Select an alternative, minimalistic output than the original one */
37#define TRACE_BLK_OPT_CLASSIC 0x1
38#define TRACE_BLK_OPT_CGROUP 0x2
39#define TRACE_BLK_OPT_CGNAME 0x4
40
41static struct tracer_opt blk_tracer_opts[] = {
42 /* Default disable the minimalistic output */
43 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
44#ifdef CONFIG_BLK_CGROUP
45 { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
46 { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
47#endif
48 { }
49};
50
51static struct tracer_flags blk_tracer_flags = {
52 .val = 0,
53 .opts = blk_tracer_opts,
54};
55
56/* Global reference count of probes */
57static DEFINE_MUTEX(blk_probe_mutex);
58static int blk_probes_ref;
59
60static void blk_register_tracepoints(void);
61static void blk_unregister_tracepoints(void);
62
63/*
64 * Send out a notify message.
65 */
66static void trace_note(struct blk_trace *bt, pid_t pid, int action,
67 const void *data, size_t len,
68 union kernfs_node_id *cgid)
69{
70 struct blk_io_trace *t;
71 struct ring_buffer_event *event = NULL;
72 struct ring_buffer *buffer = NULL;
73 int pc = 0;
74 int cpu = smp_processor_id();
75 bool blk_tracer = blk_tracer_enabled;
76 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
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 + cgid_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 + cgid_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 | (cgid ? __BLK_TN_CGROUP : 0);
100 t->pid = pid;
101 t->cpu = cpu;
102 t->pdu_len = len + cgid_len;
103 if (cgid)
104 memcpy((void *)t + sizeof(*t), cgid, cgid_len);
105 memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
106
107 if (blk_tracer)
108 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
109 }
110}
111
112/*
113 * Send out a notify for this process, if we haven't done so since a trace
114 * started
115 */
116static void trace_note_tsk(struct task_struct *tsk)
117{
118 unsigned long flags;
119 struct blk_trace *bt;
120
121 tsk->btrace_seq = blktrace_seq;
122 spin_lock_irqsave(&running_trace_lock, flags);
123 list_for_each_entry(bt, &running_trace_list, running_list) {
124 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
125 sizeof(tsk->comm), NULL);
126 }
127 spin_unlock_irqrestore(&running_trace_lock, flags);
128}
129
130static void trace_note_time(struct blk_trace *bt)
131{
132 struct timespec64 now;
133 unsigned long flags;
134 u32 words[2];
135
136 /* need to check user space to see if this breaks in y2038 or y2106 */
137 ktime_get_real_ts64(&now);
138 words[0] = (u32)now.tv_sec;
139 words[1] = now.tv_nsec;
140
141 local_irq_save(flags);
142 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), NULL);
143 local_irq_restore(flags);
144}
145
146void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
147 const char *fmt, ...)
148{
149 int n;
150 va_list args;
151 unsigned long flags;
152 char *buf;
153
154 if (unlikely(bt->trace_state != Blktrace_running &&
155 !blk_tracer_enabled))
156 return;
157
158 /*
159 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
160 * message to the trace.
161 */
162 if (!(bt->act_mask & BLK_TC_NOTIFY))
163 return;
164
165 local_irq_save(flags);
166 buf = this_cpu_ptr(bt->msg_data);
167 va_start(args, fmt);
168 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
169 va_end(args);
170
171 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
172 blkcg = NULL;
173#ifdef CONFIG_BLK_CGROUP
174 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n,
175 blkcg ? cgroup_get_kernfs_id(blkcg->css.cgroup) : NULL);
176#else
177 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL);
178#endif
179 local_irq_restore(flags);
180}
181EXPORT_SYMBOL_GPL(__trace_note_message);
182
183static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
184 pid_t pid)
185{
186 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
187 return 1;
188 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
189 return 1;
190 if (bt->pid && pid != bt->pid)
191 return 1;
192
193 return 0;
194}
195
196/*
197 * Data direction bit lookup
198 */
199static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
200 BLK_TC_ACT(BLK_TC_WRITE) };
201
202#define BLK_TC_RAHEAD BLK_TC_AHEAD
203#define BLK_TC_PREFLUSH BLK_TC_FLUSH
204
205/* The ilog2() calls fall out because they're constant */
206#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
207 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
208
209/*
210 * The worker for the various blk_add_trace*() types. Fills out a
211 * blk_io_trace structure and places it in a per-cpu subbuffer.
212 */
213static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
214 int op, int op_flags, u32 what, int error, int pdu_len,
215 void *pdu_data, union kernfs_node_id *cgid)
216{
217 struct task_struct *tsk = current;
218 struct ring_buffer_event *event = NULL;
219 struct ring_buffer *buffer = NULL;
220 struct blk_io_trace *t;
221 unsigned long flags = 0;
222 unsigned long *sequence;
223 pid_t pid;
224 int cpu, pc = 0;
225 bool blk_tracer = blk_tracer_enabled;
226 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
227
228 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
229 return;
230
231 what |= ddir_act[op_is_write(op) ? WRITE : READ];
232 what |= MASK_TC_BIT(op_flags, SYNC);
233 what |= MASK_TC_BIT(op_flags, RAHEAD);
234 what |= MASK_TC_BIT(op_flags, META);
235 what |= MASK_TC_BIT(op_flags, PREFLUSH);
236 what |= MASK_TC_BIT(op_flags, FUA);
237 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
238 what |= BLK_TC_ACT(BLK_TC_DISCARD);
239 if (op == REQ_OP_FLUSH)
240 what |= BLK_TC_ACT(BLK_TC_FLUSH);
241 if (cgid)
242 what |= __BLK_TA_CGROUP;
243
244 pid = tsk->pid;
245 if (act_log_check(bt, what, sector, pid))
246 return;
247 cpu = raw_smp_processor_id();
248
249 if (blk_tracer) {
250 tracing_record_cmdline(current);
251
252 buffer = blk_tr->trace_buffer.buffer;
253 pc = preempt_count();
254 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
255 sizeof(*t) + pdu_len + cgid_len,
256 0, pc);
257 if (!event)
258 return;
259 t = ring_buffer_event_data(event);
260 goto record_it;
261 }
262
263 if (unlikely(tsk->btrace_seq != blktrace_seq))
264 trace_note_tsk(tsk);
265
266 /*
267 * A word about the locking here - we disable interrupts to reserve
268 * some space in the relay per-cpu buffer, to prevent an irq
269 * from coming in and stepping on our toes.
270 */
271 local_irq_save(flags);
272 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
273 if (t) {
274 sequence = per_cpu_ptr(bt->sequence, cpu);
275
276 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
277 t->sequence = ++(*sequence);
278 t->time = ktime_to_ns(ktime_get());
279record_it:
280 /*
281 * These two are not needed in ftrace as they are in the
282 * generic trace_entry, filled by tracing_generic_entry_update,
283 * but for the trace_event->bin() synthesizer benefit we do it
284 * here too.
285 */
286 t->cpu = cpu;
287 t->pid = pid;
288
289 t->sector = sector;
290 t->bytes = bytes;
291 t->action = what;
292 t->device = bt->dev;
293 t->error = error;
294 t->pdu_len = pdu_len + cgid_len;
295
296 if (cgid_len)
297 memcpy((void *)t + sizeof(*t), cgid, cgid_len);
298 if (pdu_len)
299 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
300
301 if (blk_tracer) {
302 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
303 return;
304 }
305 }
306
307 local_irq_restore(flags);
308}
309
310static void blk_trace_free(struct blk_trace *bt)
311{
312 debugfs_remove(bt->msg_file);
313 debugfs_remove(bt->dropped_file);
314 relay_close(bt->rchan);
315 debugfs_remove(bt->dir);
316 free_percpu(bt->sequence);
317 free_percpu(bt->msg_data);
318 kfree(bt);
319}
320
321static void get_probe_ref(void)
322{
323 mutex_lock(&blk_probe_mutex);
324 if (++blk_probes_ref == 1)
325 blk_register_tracepoints();
326 mutex_unlock(&blk_probe_mutex);
327}
328
329static void put_probe_ref(void)
330{
331 mutex_lock(&blk_probe_mutex);
332 if (!--blk_probes_ref)
333 blk_unregister_tracepoints();
334 mutex_unlock(&blk_probe_mutex);
335}
336
337static void blk_trace_cleanup(struct blk_trace *bt)
338{
339 blk_trace_free(bt);
340 put_probe_ref();
341}
342
343static int __blk_trace_remove(struct request_queue *q)
344{
345 struct blk_trace *bt;
346
347 bt = xchg(&q->blk_trace, NULL);
348 if (!bt)
349 return -EINVAL;
350
351 if (bt->trace_state != Blktrace_running)
352 blk_trace_cleanup(bt);
353
354 return 0;
355}
356
357int blk_trace_remove(struct request_queue *q)
358{
359 int ret;
360
361 mutex_lock(&q->blk_trace_mutex);
362 ret = __blk_trace_remove(q);
363 mutex_unlock(&q->blk_trace_mutex);
364
365 return ret;
366}
367EXPORT_SYMBOL_GPL(blk_trace_remove);
368
369static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
370 size_t count, loff_t *ppos)
371{
372 struct blk_trace *bt = filp->private_data;
373 char buf[16];
374
375 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
376
377 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
378}
379
380static const struct file_operations blk_dropped_fops = {
381 .owner = THIS_MODULE,
382 .open = simple_open,
383 .read = blk_dropped_read,
384 .llseek = default_llseek,
385};
386
387static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
388 size_t count, loff_t *ppos)
389{
390 char *msg;
391 struct blk_trace *bt;
392
393 if (count >= BLK_TN_MAX_MSG)
394 return -EINVAL;
395
396 msg = memdup_user_nul(buffer, count);
397 if (IS_ERR(msg))
398 return PTR_ERR(msg);
399
400 bt = filp->private_data;
401 __trace_note_message(bt, NULL, "%s", msg);
402 kfree(msg);
403
404 return count;
405}
406
407static const struct file_operations blk_msg_fops = {
408 .owner = THIS_MODULE,
409 .open = simple_open,
410 .write = blk_msg_write,
411 .llseek = noop_llseek,
412};
413
414/*
415 * Keep track of how many times we encountered a full subbuffer, to aid
416 * the user space app in telling how many lost events there were.
417 */
418static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
419 void *prev_subbuf, size_t prev_padding)
420{
421 struct blk_trace *bt;
422
423 if (!relay_buf_full(buf))
424 return 1;
425
426 bt = buf->chan->private_data;
427 atomic_inc(&bt->dropped);
428 return 0;
429}
430
431static int blk_remove_buf_file_callback(struct dentry *dentry)
432{
433 debugfs_remove(dentry);
434
435 return 0;
436}
437
438static struct dentry *blk_create_buf_file_callback(const char *filename,
439 struct dentry *parent,
440 umode_t mode,
441 struct rchan_buf *buf,
442 int *is_global)
443{
444 return debugfs_create_file(filename, mode, parent, buf,
445 &relay_file_operations);
446}
447
448static struct rchan_callbacks blk_relay_callbacks = {
449 .subbuf_start = blk_subbuf_start_callback,
450 .create_buf_file = blk_create_buf_file_callback,
451 .remove_buf_file = blk_remove_buf_file_callback,
452};
453
454static void blk_trace_setup_lba(struct blk_trace *bt,
455 struct block_device *bdev)
456{
457 struct hd_struct *part = NULL;
458
459 if (bdev)
460 part = bdev->bd_part;
461
462 if (part) {
463 bt->start_lba = part->start_sect;
464 bt->end_lba = part->start_sect + part->nr_sects;
465 } else {
466 bt->start_lba = 0;
467 bt->end_lba = -1ULL;
468 }
469}
470
471/*
472 * Setup everything required to start tracing
473 */
474static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
475 struct block_device *bdev,
476 struct blk_user_trace_setup *buts)
477{
478 struct blk_trace *bt = NULL;
479 struct dentry *dir = NULL;
480 int ret;
481
482 if (!buts->buf_size || !buts->buf_nr)
483 return -EINVAL;
484
485 if (!blk_debugfs_root)
486 return -ENOENT;
487
488 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
489 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
490
491 /*
492 * some device names have larger paths - convert the slashes
493 * to underscores for this to work as expected
494 */
495 strreplace(buts->name, '/', '_');
496
497 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
498 if (!bt)
499 return -ENOMEM;
500
501 ret = -ENOMEM;
502 bt->sequence = alloc_percpu(unsigned long);
503 if (!bt->sequence)
504 goto err;
505
506 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
507 if (!bt->msg_data)
508 goto err;
509
510 ret = -ENOENT;
511
512 dir = debugfs_lookup(buts->name, blk_debugfs_root);
513 if (!dir)
514 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
515
516 bt->dev = dev;
517 atomic_set(&bt->dropped, 0);
518 INIT_LIST_HEAD(&bt->running_list);
519
520 ret = -EIO;
521 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
522 &blk_dropped_fops);
523
524 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
525
526 bt->rchan = relay_open("trace", dir, buts->buf_size,
527 buts->buf_nr, &blk_relay_callbacks, bt);
528 if (!bt->rchan)
529 goto err;
530
531 bt->act_mask = buts->act_mask;
532 if (!bt->act_mask)
533 bt->act_mask = (u16) -1;
534
535 blk_trace_setup_lba(bt, bdev);
536
537 /* overwrite with user settings */
538 if (buts->start_lba)
539 bt->start_lba = buts->start_lba;
540 if (buts->end_lba)
541 bt->end_lba = buts->end_lba;
542
543 bt->pid = buts->pid;
544 bt->trace_state = Blktrace_setup;
545
546 ret = -EBUSY;
547 if (cmpxchg(&q->blk_trace, NULL, bt))
548 goto err;
549
550 get_probe_ref();
551
552 ret = 0;
553err:
554 if (dir && !bt->dir)
555 dput(dir);
556 if (ret)
557 blk_trace_free(bt);
558 return ret;
559}
560
561static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
562 struct block_device *bdev, char __user *arg)
563{
564 struct blk_user_trace_setup buts;
565 int ret;
566
567 ret = copy_from_user(&buts, arg, sizeof(buts));
568 if (ret)
569 return -EFAULT;
570
571 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
572 if (ret)
573 return ret;
574
575 if (copy_to_user(arg, &buts, sizeof(buts))) {
576 __blk_trace_remove(q);
577 return -EFAULT;
578 }
579 return 0;
580}
581
582int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
583 struct block_device *bdev,
584 char __user *arg)
585{
586 int ret;
587
588 mutex_lock(&q->blk_trace_mutex);
589 ret = __blk_trace_setup(q, name, dev, bdev, arg);
590 mutex_unlock(&q->blk_trace_mutex);
591
592 return ret;
593}
594EXPORT_SYMBOL_GPL(blk_trace_setup);
595
596#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
597static int compat_blk_trace_setup(struct request_queue *q, char *name,
598 dev_t dev, struct block_device *bdev,
599 char __user *arg)
600{
601 struct blk_user_trace_setup buts;
602 struct compat_blk_user_trace_setup cbuts;
603 int ret;
604
605 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
606 return -EFAULT;
607
608 buts = (struct blk_user_trace_setup) {
609 .act_mask = cbuts.act_mask,
610 .buf_size = cbuts.buf_size,
611 .buf_nr = cbuts.buf_nr,
612 .start_lba = cbuts.start_lba,
613 .end_lba = cbuts.end_lba,
614 .pid = cbuts.pid,
615 };
616
617 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
618 if (ret)
619 return ret;
620
621 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
622 __blk_trace_remove(q);
623 return -EFAULT;
624 }
625
626 return 0;
627}
628#endif
629
630static int __blk_trace_startstop(struct request_queue *q, int start)
631{
632 int ret;
633 struct blk_trace *bt = q->blk_trace;
634
635 if (bt == NULL)
636 return -EINVAL;
637
638 /*
639 * For starting a trace, we can transition from a setup or stopped
640 * trace. For stopping a trace, the state must be running
641 */
642 ret = -EINVAL;
643 if (start) {
644 if (bt->trace_state == Blktrace_setup ||
645 bt->trace_state == Blktrace_stopped) {
646 blktrace_seq++;
647 smp_mb();
648 bt->trace_state = Blktrace_running;
649 spin_lock_irq(&running_trace_lock);
650 list_add(&bt->running_list, &running_trace_list);
651 spin_unlock_irq(&running_trace_lock);
652
653 trace_note_time(bt);
654 ret = 0;
655 }
656 } else {
657 if (bt->trace_state == Blktrace_running) {
658 bt->trace_state = Blktrace_stopped;
659 spin_lock_irq(&running_trace_lock);
660 list_del_init(&bt->running_list);
661 spin_unlock_irq(&running_trace_lock);
662 relay_flush(bt->rchan);
663 ret = 0;
664 }
665 }
666
667 return ret;
668}
669
670int blk_trace_startstop(struct request_queue *q, int start)
671{
672 int ret;
673
674 mutex_lock(&q->blk_trace_mutex);
675 ret = __blk_trace_startstop(q, start);
676 mutex_unlock(&q->blk_trace_mutex);
677
678 return ret;
679}
680EXPORT_SYMBOL_GPL(blk_trace_startstop);
681
682/*
683 * When reading or writing the blktrace sysfs files, the references to the
684 * opened sysfs or device files should prevent the underlying block device
685 * from being removed. So no further delete protection is really needed.
686 */
687
688/**
689 * blk_trace_ioctl: - handle the ioctls associated with tracing
690 * @bdev: the block device
691 * @cmd: the ioctl cmd
692 * @arg: the argument data, if any
693 *
694 **/
695int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
696{
697 struct request_queue *q;
698 int ret, start = 0;
699 char b[BDEVNAME_SIZE];
700
701 q = bdev_get_queue(bdev);
702 if (!q)
703 return -ENXIO;
704
705 mutex_lock(&q->blk_trace_mutex);
706
707 switch (cmd) {
708 case BLKTRACESETUP:
709 bdevname(bdev, b);
710 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
711 break;
712#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
713 case BLKTRACESETUP32:
714 bdevname(bdev, b);
715 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
716 break;
717#endif
718 case BLKTRACESTART:
719 start = 1;
720 /* fall through */
721 case BLKTRACESTOP:
722 ret = __blk_trace_startstop(q, start);
723 break;
724 case BLKTRACETEARDOWN:
725 ret = __blk_trace_remove(q);
726 break;
727 default:
728 ret = -ENOTTY;
729 break;
730 }
731
732 mutex_unlock(&q->blk_trace_mutex);
733 return ret;
734}
735
736/**
737 * blk_trace_shutdown: - stop and cleanup trace structures
738 * @q: the request queue associated with the device
739 *
740 **/
741void blk_trace_shutdown(struct request_queue *q)
742{
743 mutex_lock(&q->blk_trace_mutex);
744
745 if (q->blk_trace) {
746 __blk_trace_startstop(q, 0);
747 __blk_trace_remove(q);
748 }
749
750 mutex_unlock(&q->blk_trace_mutex);
751}
752
753#ifdef CONFIG_BLK_CGROUP
754static union kernfs_node_id *
755blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
756{
757 struct blk_trace *bt = q->blk_trace;
758
759 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
760 return NULL;
761
762 if (!bio->bi_blkg)
763 return NULL;
764 return cgroup_get_kernfs_id(bio_blkcg(bio)->css.cgroup);
765}
766#else
767static union kernfs_node_id *
768blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
769{
770 return NULL;
771}
772#endif
773
774static union kernfs_node_id *
775blk_trace_request_get_cgid(struct request_queue *q, struct request *rq)
776{
777 if (!rq->bio)
778 return NULL;
779 /* Use the first bio */
780 return blk_trace_bio_get_cgid(q, rq->bio);
781}
782
783/*
784 * blktrace probes
785 */
786
787/**
788 * blk_add_trace_rq - Add a trace for a request oriented action
789 * @rq: the source request
790 * @error: return status to log
791 * @nr_bytes: number of completed bytes
792 * @what: the action
793 * @cgid: the cgroup info
794 *
795 * Description:
796 * Records an action against a request. Will log the bio offset + size.
797 *
798 **/
799static void blk_add_trace_rq(struct request *rq, int error,
800 unsigned int nr_bytes, u32 what,
801 union kernfs_node_id *cgid)
802{
803 struct blk_trace *bt = rq->q->blk_trace;
804
805 if (likely(!bt))
806 return;
807
808 if (blk_rq_is_passthrough(rq))
809 what |= BLK_TC_ACT(BLK_TC_PC);
810 else
811 what |= BLK_TC_ACT(BLK_TC_FS);
812
813 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
814 rq->cmd_flags, what, error, 0, NULL, cgid);
815}
816
817static void blk_add_trace_rq_insert(void *ignore,
818 struct request_queue *q, struct request *rq)
819{
820 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
821 blk_trace_request_get_cgid(q, rq));
822}
823
824static void blk_add_trace_rq_issue(void *ignore,
825 struct request_queue *q, struct request *rq)
826{
827 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
828 blk_trace_request_get_cgid(q, rq));
829}
830
831static void blk_add_trace_rq_requeue(void *ignore,
832 struct request_queue *q,
833 struct request *rq)
834{
835 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
836 blk_trace_request_get_cgid(q, rq));
837}
838
839static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
840 int error, unsigned int nr_bytes)
841{
842 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
843 blk_trace_request_get_cgid(rq->q, rq));
844}
845
846/**
847 * blk_add_trace_bio - Add a trace for a bio oriented action
848 * @q: queue the io is for
849 * @bio: the source bio
850 * @what: the action
851 * @error: error, if any
852 *
853 * Description:
854 * Records an action against a bio. Will log the bio offset + size.
855 *
856 **/
857static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
858 u32 what, int error)
859{
860 struct blk_trace *bt = q->blk_trace;
861
862 if (likely(!bt))
863 return;
864
865 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
866 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
867 blk_trace_bio_get_cgid(q, bio));
868}
869
870static void blk_add_trace_bio_bounce(void *ignore,
871 struct request_queue *q, struct bio *bio)
872{
873 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
874}
875
876static void blk_add_trace_bio_complete(void *ignore,
877 struct request_queue *q, struct bio *bio,
878 int error)
879{
880 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
881}
882
883static void blk_add_trace_bio_backmerge(void *ignore,
884 struct request_queue *q,
885 struct request *rq,
886 struct bio *bio)
887{
888 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
889}
890
891static void blk_add_trace_bio_frontmerge(void *ignore,
892 struct request_queue *q,
893 struct request *rq,
894 struct bio *bio)
895{
896 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
897}
898
899static void blk_add_trace_bio_queue(void *ignore,
900 struct request_queue *q, struct bio *bio)
901{
902 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
903}
904
905static void blk_add_trace_getrq(void *ignore,
906 struct request_queue *q,
907 struct bio *bio, int rw)
908{
909 if (bio)
910 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
911 else {
912 struct blk_trace *bt = q->blk_trace;
913
914 if (bt)
915 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
916 NULL, NULL);
917 }
918}
919
920
921static void blk_add_trace_sleeprq(void *ignore,
922 struct request_queue *q,
923 struct bio *bio, int rw)
924{
925 if (bio)
926 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
927 else {
928 struct blk_trace *bt = q->blk_trace;
929
930 if (bt)
931 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
932 0, 0, NULL, NULL);
933 }
934}
935
936static void blk_add_trace_plug(void *ignore, struct request_queue *q)
937{
938 struct blk_trace *bt = q->blk_trace;
939
940 if (bt)
941 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, NULL);
942}
943
944static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
945 unsigned int depth, bool explicit)
946{
947 struct blk_trace *bt = q->blk_trace;
948
949 if (bt) {
950 __be64 rpdu = cpu_to_be64(depth);
951 u32 what;
952
953 if (explicit)
954 what = BLK_TA_UNPLUG_IO;
955 else
956 what = BLK_TA_UNPLUG_TIMER;
957
958 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, NULL);
959 }
960}
961
962static void blk_add_trace_split(void *ignore,
963 struct request_queue *q, struct bio *bio,
964 unsigned int pdu)
965{
966 struct blk_trace *bt = q->blk_trace;
967
968 if (bt) {
969 __be64 rpdu = cpu_to_be64(pdu);
970
971 __blk_add_trace(bt, bio->bi_iter.bi_sector,
972 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
973 BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu),
974 &rpdu, blk_trace_bio_get_cgid(q, bio));
975 }
976}
977
978/**
979 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
980 * @ignore: trace callback data parameter (not used)
981 * @q: queue the io is for
982 * @bio: the source bio
983 * @dev: target device
984 * @from: source sector
985 *
986 * Description:
987 * Device mapper or raid target sometimes need to split a bio because
988 * it spans a stripe (or similar). Add a trace for that action.
989 *
990 **/
991static void blk_add_trace_bio_remap(void *ignore,
992 struct request_queue *q, struct bio *bio,
993 dev_t dev, sector_t from)
994{
995 struct blk_trace *bt = q->blk_trace;
996 struct blk_io_trace_remap r;
997
998 if (likely(!bt))
999 return;
1000
1001 r.device_from = cpu_to_be32(dev);
1002 r.device_to = cpu_to_be32(bio_dev(bio));
1003 r.sector_from = cpu_to_be64(from);
1004
1005 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1006 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status,
1007 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1008}
1009
1010/**
1011 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1012 * @ignore: trace callback data parameter (not used)
1013 * @q: queue the io is for
1014 * @rq: the source request
1015 * @dev: target device
1016 * @from: source sector
1017 *
1018 * Description:
1019 * Device mapper remaps request to other devices.
1020 * Add a trace for that action.
1021 *
1022 **/
1023static void blk_add_trace_rq_remap(void *ignore,
1024 struct request_queue *q,
1025 struct request *rq, dev_t dev,
1026 sector_t from)
1027{
1028 struct blk_trace *bt = q->blk_trace;
1029 struct blk_io_trace_remap r;
1030
1031 if (likely(!bt))
1032 return;
1033
1034 r.device_from = cpu_to_be32(dev);
1035 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1036 r.sector_from = cpu_to_be64(from);
1037
1038 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1039 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1040 sizeof(r), &r, blk_trace_request_get_cgid(q, rq));
1041}
1042
1043/**
1044 * blk_add_driver_data - Add binary message with driver-specific data
1045 * @q: queue the io is for
1046 * @rq: io request
1047 * @data: driver-specific data
1048 * @len: length of driver-specific data
1049 *
1050 * Description:
1051 * Some drivers might want to write driver-specific data per request.
1052 *
1053 **/
1054void blk_add_driver_data(struct request_queue *q,
1055 struct request *rq,
1056 void *data, size_t len)
1057{
1058 struct blk_trace *bt = q->blk_trace;
1059
1060 if (likely(!bt))
1061 return;
1062
1063 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1064 BLK_TA_DRV_DATA, 0, len, data,
1065 blk_trace_request_get_cgid(q, rq));
1066}
1067EXPORT_SYMBOL_GPL(blk_add_driver_data);
1068
1069static void blk_register_tracepoints(void)
1070{
1071 int ret;
1072
1073 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1074 WARN_ON(ret);
1075 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1076 WARN_ON(ret);
1077 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1078 WARN_ON(ret);
1079 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1080 WARN_ON(ret);
1081 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1082 WARN_ON(ret);
1083 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1084 WARN_ON(ret);
1085 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1086 WARN_ON(ret);
1087 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1088 WARN_ON(ret);
1089 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1090 WARN_ON(ret);
1091 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1092 WARN_ON(ret);
1093 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1094 WARN_ON(ret);
1095 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1096 WARN_ON(ret);
1097 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1098 WARN_ON(ret);
1099 ret = register_trace_block_split(blk_add_trace_split, NULL);
1100 WARN_ON(ret);
1101 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1102 WARN_ON(ret);
1103 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1104 WARN_ON(ret);
1105}
1106
1107static void blk_unregister_tracepoints(void)
1108{
1109 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1110 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1111 unregister_trace_block_split(blk_add_trace_split, NULL);
1112 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1113 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1114 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1115 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1116 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1117 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1118 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1119 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1120 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1121 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1122 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1123 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1124 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1125
1126 tracepoint_synchronize_unregister();
1127}
1128
1129/*
1130 * struct blk_io_tracer formatting routines
1131 */
1132
1133static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1134{
1135 int i = 0;
1136 int tc = t->action >> BLK_TC_SHIFT;
1137
1138 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1139 rwbs[i++] = 'N';
1140 goto out;
1141 }
1142
1143 if (tc & BLK_TC_FLUSH)
1144 rwbs[i++] = 'F';
1145
1146 if (tc & BLK_TC_DISCARD)
1147 rwbs[i++] = 'D';
1148 else if (tc & BLK_TC_WRITE)
1149 rwbs[i++] = 'W';
1150 else if (t->bytes)
1151 rwbs[i++] = 'R';
1152 else
1153 rwbs[i++] = 'N';
1154
1155 if (tc & BLK_TC_FUA)
1156 rwbs[i++] = 'F';
1157 if (tc & BLK_TC_AHEAD)
1158 rwbs[i++] = 'A';
1159 if (tc & BLK_TC_SYNC)
1160 rwbs[i++] = 'S';
1161 if (tc & BLK_TC_META)
1162 rwbs[i++] = 'M';
1163out:
1164 rwbs[i] = '\0';
1165}
1166
1167static inline
1168const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1169{
1170 return (const struct blk_io_trace *)ent;
1171}
1172
1173static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1174{
1175 return (void *)(te_blk_io_trace(ent) + 1) +
1176 (has_cg ? sizeof(union kernfs_node_id) : 0);
1177}
1178
1179static inline const void *cgid_start(const struct trace_entry *ent)
1180{
1181 return (void *)(te_blk_io_trace(ent) + 1);
1182}
1183
1184static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1185{
1186 return te_blk_io_trace(ent)->pdu_len -
1187 (has_cg ? sizeof(union kernfs_node_id) : 0);
1188}
1189
1190static inline u32 t_action(const struct trace_entry *ent)
1191{
1192 return te_blk_io_trace(ent)->action;
1193}
1194
1195static inline u32 t_bytes(const struct trace_entry *ent)
1196{
1197 return te_blk_io_trace(ent)->bytes;
1198}
1199
1200static inline u32 t_sec(const struct trace_entry *ent)
1201{
1202 return te_blk_io_trace(ent)->bytes >> 9;
1203}
1204
1205static inline unsigned long long t_sector(const struct trace_entry *ent)
1206{
1207 return te_blk_io_trace(ent)->sector;
1208}
1209
1210static inline __u16 t_error(const struct trace_entry *ent)
1211{
1212 return te_blk_io_trace(ent)->error;
1213}
1214
1215static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1216{
1217 const __u64 *val = pdu_start(ent, has_cg);
1218 return be64_to_cpu(*val);
1219}
1220
1221static void get_pdu_remap(const struct trace_entry *ent,
1222 struct blk_io_trace_remap *r, bool has_cg)
1223{
1224 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1225 __u64 sector_from = __r->sector_from;
1226
1227 r->device_from = be32_to_cpu(__r->device_from);
1228 r->device_to = be32_to_cpu(__r->device_to);
1229 r->sector_from = be64_to_cpu(sector_from);
1230}
1231
1232typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1233 bool has_cg);
1234
1235static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1236 bool has_cg)
1237{
1238 char rwbs[RWBS_LEN];
1239 unsigned long long ts = iter->ts;
1240 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1241 unsigned secs = (unsigned long)ts;
1242 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1243
1244 fill_rwbs(rwbs, t);
1245
1246 trace_seq_printf(&iter->seq,
1247 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1248 MAJOR(t->device), MINOR(t->device), iter->cpu,
1249 secs, nsec_rem, iter->ent->pid, act, rwbs);
1250}
1251
1252static void blk_log_action(struct trace_iterator *iter, const char *act,
1253 bool has_cg)
1254{
1255 char rwbs[RWBS_LEN];
1256 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1257
1258 fill_rwbs(rwbs, t);
1259 if (has_cg) {
1260 const union kernfs_node_id *id = cgid_start(iter->ent);
1261
1262 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1263 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1264
1265 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1266 sizeof(blkcg_name_buf));
1267 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1268 MAJOR(t->device), MINOR(t->device),
1269 blkcg_name_buf, act, rwbs);
1270 } else
1271 trace_seq_printf(&iter->seq,
1272 "%3d,%-3d %x,%-x %2s %3s ",
1273 MAJOR(t->device), MINOR(t->device),
1274 id->ino, id->generation, act, rwbs);
1275 } else
1276 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1277 MAJOR(t->device), MINOR(t->device), act, rwbs);
1278}
1279
1280static void blk_log_dump_pdu(struct trace_seq *s,
1281 const struct trace_entry *ent, bool has_cg)
1282{
1283 const unsigned char *pdu_buf;
1284 int pdu_len;
1285 int i, end;
1286
1287 pdu_buf = pdu_start(ent, has_cg);
1288 pdu_len = pdu_real_len(ent, has_cg);
1289
1290 if (!pdu_len)
1291 return;
1292
1293 /* find the last zero that needs to be printed */
1294 for (end = pdu_len - 1; end >= 0; end--)
1295 if (pdu_buf[end])
1296 break;
1297 end++;
1298
1299 trace_seq_putc(s, '(');
1300
1301 for (i = 0; i < pdu_len; i++) {
1302
1303 trace_seq_printf(s, "%s%02x",
1304 i == 0 ? "" : " ", pdu_buf[i]);
1305
1306 /*
1307 * stop when the rest is just zeroes and indicate so
1308 * with a ".." appended
1309 */
1310 if (i == end && end != pdu_len - 1) {
1311 trace_seq_puts(s, " ..) ");
1312 return;
1313 }
1314 }
1315
1316 trace_seq_puts(s, ") ");
1317}
1318
1319static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1320{
1321 char cmd[TASK_COMM_LEN];
1322
1323 trace_find_cmdline(ent->pid, cmd);
1324
1325 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1326 trace_seq_printf(s, "%u ", t_bytes(ent));
1327 blk_log_dump_pdu(s, ent, has_cg);
1328 trace_seq_printf(s, "[%s]\n", cmd);
1329 } else {
1330 if (t_sec(ent))
1331 trace_seq_printf(s, "%llu + %u [%s]\n",
1332 t_sector(ent), t_sec(ent), cmd);
1333 else
1334 trace_seq_printf(s, "[%s]\n", cmd);
1335 }
1336}
1337
1338static void blk_log_with_error(struct trace_seq *s,
1339 const struct trace_entry *ent, bool has_cg)
1340{
1341 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1342 blk_log_dump_pdu(s, ent, has_cg);
1343 trace_seq_printf(s, "[%d]\n", t_error(ent));
1344 } else {
1345 if (t_sec(ent))
1346 trace_seq_printf(s, "%llu + %u [%d]\n",
1347 t_sector(ent),
1348 t_sec(ent), t_error(ent));
1349 else
1350 trace_seq_printf(s, "%llu [%d]\n",
1351 t_sector(ent), t_error(ent));
1352 }
1353}
1354
1355static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1356{
1357 struct blk_io_trace_remap r = { .device_from = 0, };
1358
1359 get_pdu_remap(ent, &r, has_cg);
1360 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1361 t_sector(ent), t_sec(ent),
1362 MAJOR(r.device_from), MINOR(r.device_from),
1363 (unsigned long long)r.sector_from);
1364}
1365
1366static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1367{
1368 char cmd[TASK_COMM_LEN];
1369
1370 trace_find_cmdline(ent->pid, cmd);
1371
1372 trace_seq_printf(s, "[%s]\n", cmd);
1373}
1374
1375static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1376{
1377 char cmd[TASK_COMM_LEN];
1378
1379 trace_find_cmdline(ent->pid, cmd);
1380
1381 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1382}
1383
1384static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1385{
1386 char cmd[TASK_COMM_LEN];
1387
1388 trace_find_cmdline(ent->pid, cmd);
1389
1390 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1391 get_pdu_int(ent, has_cg), cmd);
1392}
1393
1394static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1395 bool has_cg)
1396{
1397
1398 trace_seq_putmem(s, pdu_start(ent, has_cg),
1399 pdu_real_len(ent, has_cg));
1400 trace_seq_putc(s, '\n');
1401}
1402
1403/*
1404 * struct tracer operations
1405 */
1406
1407static void blk_tracer_print_header(struct seq_file *m)
1408{
1409 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1410 return;
1411 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1412 "# | | | | | |\n");
1413}
1414
1415static void blk_tracer_start(struct trace_array *tr)
1416{
1417 blk_tracer_enabled = true;
1418}
1419
1420static int blk_tracer_init(struct trace_array *tr)
1421{
1422 blk_tr = tr;
1423 blk_tracer_start(tr);
1424 return 0;
1425}
1426
1427static void blk_tracer_stop(struct trace_array *tr)
1428{
1429 blk_tracer_enabled = false;
1430}
1431
1432static void blk_tracer_reset(struct trace_array *tr)
1433{
1434 blk_tracer_stop(tr);
1435}
1436
1437static const struct {
1438 const char *act[2];
1439 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1440 bool has_cg);
1441} what2act[] = {
1442 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1443 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1444 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1445 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1446 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1447 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1448 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1449 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1450 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1451 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1452 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1453 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1454 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1455 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1456 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1457};
1458
1459static enum print_line_t print_one_line(struct trace_iterator *iter,
1460 bool classic)
1461{
1462 struct trace_array *tr = iter->tr;
1463 struct trace_seq *s = &iter->seq;
1464 const struct blk_io_trace *t;
1465 u16 what;
1466 bool long_act;
1467 blk_log_action_t *log_action;
1468 bool has_cg;
1469
1470 t = te_blk_io_trace(iter->ent);
1471 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1472 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1473 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1474 has_cg = t->action & __BLK_TA_CGROUP;
1475
1476 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1477 log_action(iter, long_act ? "message" : "m", has_cg);
1478 blk_log_msg(s, iter->ent, has_cg);
1479 return trace_handle_return(s);
1480 }
1481
1482 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1483 trace_seq_printf(s, "Unknown action %x\n", what);
1484 else {
1485 log_action(iter, what2act[what].act[long_act], has_cg);
1486 what2act[what].print(s, iter->ent, has_cg);
1487 }
1488
1489 return trace_handle_return(s);
1490}
1491
1492static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1493 int flags, struct trace_event *event)
1494{
1495 return print_one_line(iter, false);
1496}
1497
1498static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1499{
1500 struct trace_seq *s = &iter->seq;
1501 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1502 const int offset = offsetof(struct blk_io_trace, sector);
1503 struct blk_io_trace old = {
1504 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1505 .time = iter->ts,
1506 };
1507
1508 trace_seq_putmem(s, &old, offset);
1509 trace_seq_putmem(s, &t->sector,
1510 sizeof(old) - offset + t->pdu_len);
1511}
1512
1513static enum print_line_t
1514blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1515 struct trace_event *event)
1516{
1517 blk_trace_synthesize_old_trace(iter);
1518
1519 return trace_handle_return(&iter->seq);
1520}
1521
1522static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1523{
1524 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1525 return TRACE_TYPE_UNHANDLED;
1526
1527 return print_one_line(iter, true);
1528}
1529
1530static int
1531blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1532{
1533 /* don't output context-info for blk_classic output */
1534 if (bit == TRACE_BLK_OPT_CLASSIC) {
1535 if (set)
1536 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1537 else
1538 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1539 }
1540 return 0;
1541}
1542
1543static struct tracer blk_tracer __read_mostly = {
1544 .name = "blk",
1545 .init = blk_tracer_init,
1546 .reset = blk_tracer_reset,
1547 .start = blk_tracer_start,
1548 .stop = blk_tracer_stop,
1549 .print_header = blk_tracer_print_header,
1550 .print_line = blk_tracer_print_line,
1551 .flags = &blk_tracer_flags,
1552 .set_flag = blk_tracer_set_flag,
1553};
1554
1555static struct trace_event_functions trace_blk_event_funcs = {
1556 .trace = blk_trace_event_print,
1557 .binary = blk_trace_event_print_binary,
1558};
1559
1560static struct trace_event trace_blk_event = {
1561 .type = TRACE_BLK,
1562 .funcs = &trace_blk_event_funcs,
1563};
1564
1565static int __init init_blk_tracer(void)
1566{
1567 if (!register_trace_event(&trace_blk_event)) {
1568 pr_warn("Warning: could not register block events\n");
1569 return 1;
1570 }
1571
1572 if (register_tracer(&blk_tracer) != 0) {
1573 pr_warn("Warning: could not register the block tracer\n");
1574 unregister_trace_event(&trace_blk_event);
1575 return 1;
1576 }
1577
1578 return 0;
1579}
1580
1581device_initcall(init_blk_tracer);
1582
1583static int blk_trace_remove_queue(struct request_queue *q)
1584{
1585 struct blk_trace *bt;
1586
1587 bt = xchg(&q->blk_trace, NULL);
1588 if (bt == NULL)
1589 return -EINVAL;
1590
1591 put_probe_ref();
1592 blk_trace_free(bt);
1593 return 0;
1594}
1595
1596/*
1597 * Setup everything required to start tracing
1598 */
1599static int blk_trace_setup_queue(struct request_queue *q,
1600 struct block_device *bdev)
1601{
1602 struct blk_trace *bt = NULL;
1603 int ret = -ENOMEM;
1604
1605 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1606 if (!bt)
1607 return -ENOMEM;
1608
1609 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1610 if (!bt->msg_data)
1611 goto free_bt;
1612
1613 bt->dev = bdev->bd_dev;
1614 bt->act_mask = (u16)-1;
1615
1616 blk_trace_setup_lba(bt, bdev);
1617
1618 ret = -EBUSY;
1619 if (cmpxchg(&q->blk_trace, NULL, bt))
1620 goto free_bt;
1621
1622 get_probe_ref();
1623 return 0;
1624
1625free_bt:
1626 blk_trace_free(bt);
1627 return ret;
1628}
1629
1630/*
1631 * sysfs interface to enable and configure tracing
1632 */
1633
1634static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1635 struct device_attribute *attr,
1636 char *buf);
1637static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1638 struct device_attribute *attr,
1639 const char *buf, size_t count);
1640#define BLK_TRACE_DEVICE_ATTR(_name) \
1641 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1642 sysfs_blk_trace_attr_show, \
1643 sysfs_blk_trace_attr_store)
1644
1645static BLK_TRACE_DEVICE_ATTR(enable);
1646static BLK_TRACE_DEVICE_ATTR(act_mask);
1647static BLK_TRACE_DEVICE_ATTR(pid);
1648static BLK_TRACE_DEVICE_ATTR(start_lba);
1649static BLK_TRACE_DEVICE_ATTR(end_lba);
1650
1651static struct attribute *blk_trace_attrs[] = {
1652 &dev_attr_enable.attr,
1653 &dev_attr_act_mask.attr,
1654 &dev_attr_pid.attr,
1655 &dev_attr_start_lba.attr,
1656 &dev_attr_end_lba.attr,
1657 NULL
1658};
1659
1660struct attribute_group blk_trace_attr_group = {
1661 .name = "trace",
1662 .attrs = blk_trace_attrs,
1663};
1664
1665static const struct {
1666 int mask;
1667 const char *str;
1668} mask_maps[] = {
1669 { BLK_TC_READ, "read" },
1670 { BLK_TC_WRITE, "write" },
1671 { BLK_TC_FLUSH, "flush" },
1672 { BLK_TC_SYNC, "sync" },
1673 { BLK_TC_QUEUE, "queue" },
1674 { BLK_TC_REQUEUE, "requeue" },
1675 { BLK_TC_ISSUE, "issue" },
1676 { BLK_TC_COMPLETE, "complete" },
1677 { BLK_TC_FS, "fs" },
1678 { BLK_TC_PC, "pc" },
1679 { BLK_TC_NOTIFY, "notify" },
1680 { BLK_TC_AHEAD, "ahead" },
1681 { BLK_TC_META, "meta" },
1682 { BLK_TC_DISCARD, "discard" },
1683 { BLK_TC_DRV_DATA, "drv_data" },
1684 { BLK_TC_FUA, "fua" },
1685};
1686
1687static int blk_trace_str2mask(const char *str)
1688{
1689 int i;
1690 int mask = 0;
1691 char *buf, *s, *token;
1692
1693 buf = kstrdup(str, GFP_KERNEL);
1694 if (buf == NULL)
1695 return -ENOMEM;
1696 s = strstrip(buf);
1697
1698 while (1) {
1699 token = strsep(&s, ",");
1700 if (token == NULL)
1701 break;
1702
1703 if (*token == '\0')
1704 continue;
1705
1706 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1707 if (strcasecmp(token, mask_maps[i].str) == 0) {
1708 mask |= mask_maps[i].mask;
1709 break;
1710 }
1711 }
1712 if (i == ARRAY_SIZE(mask_maps)) {
1713 mask = -EINVAL;
1714 break;
1715 }
1716 }
1717 kfree(buf);
1718
1719 return mask;
1720}
1721
1722static ssize_t blk_trace_mask2str(char *buf, int mask)
1723{
1724 int i;
1725 char *p = buf;
1726
1727 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1728 if (mask & mask_maps[i].mask) {
1729 p += sprintf(p, "%s%s",
1730 (p == buf) ? "" : ",", mask_maps[i].str);
1731 }
1732 }
1733 *p++ = '\n';
1734
1735 return p - buf;
1736}
1737
1738static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1739{
1740 if (bdev->bd_disk == NULL)
1741 return NULL;
1742
1743 return bdev_get_queue(bdev);
1744}
1745
1746static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1747 struct device_attribute *attr,
1748 char *buf)
1749{
1750 struct hd_struct *p = dev_to_part(dev);
1751 struct request_queue *q;
1752 struct block_device *bdev;
1753 ssize_t ret = -ENXIO;
1754
1755 bdev = bdget(part_devt(p));
1756 if (bdev == NULL)
1757 goto out;
1758
1759 q = blk_trace_get_queue(bdev);
1760 if (q == NULL)
1761 goto out_bdput;
1762
1763 mutex_lock(&q->blk_trace_mutex);
1764
1765 if (attr == &dev_attr_enable) {
1766 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1767 goto out_unlock_bdev;
1768 }
1769
1770 if (q->blk_trace == NULL)
1771 ret = sprintf(buf, "disabled\n");
1772 else if (attr == &dev_attr_act_mask)
1773 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1774 else if (attr == &dev_attr_pid)
1775 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1776 else if (attr == &dev_attr_start_lba)
1777 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1778 else if (attr == &dev_attr_end_lba)
1779 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1780
1781out_unlock_bdev:
1782 mutex_unlock(&q->blk_trace_mutex);
1783out_bdput:
1784 bdput(bdev);
1785out:
1786 return ret;
1787}
1788
1789static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1790 struct device_attribute *attr,
1791 const char *buf, size_t count)
1792{
1793 struct block_device *bdev;
1794 struct request_queue *q;
1795 struct hd_struct *p;
1796 u64 value;
1797 ssize_t ret = -EINVAL;
1798
1799 if (count == 0)
1800 goto out;
1801
1802 if (attr == &dev_attr_act_mask) {
1803 if (kstrtoull(buf, 0, &value)) {
1804 /* Assume it is a list of trace category names */
1805 ret = blk_trace_str2mask(buf);
1806 if (ret < 0)
1807 goto out;
1808 value = ret;
1809 }
1810 } else if (kstrtoull(buf, 0, &value))
1811 goto out;
1812
1813 ret = -ENXIO;
1814
1815 p = dev_to_part(dev);
1816 bdev = bdget(part_devt(p));
1817 if (bdev == NULL)
1818 goto out;
1819
1820 q = blk_trace_get_queue(bdev);
1821 if (q == NULL)
1822 goto out_bdput;
1823
1824 mutex_lock(&q->blk_trace_mutex);
1825
1826 if (attr == &dev_attr_enable) {
1827 if (!!value == !!q->blk_trace) {
1828 ret = 0;
1829 goto out_unlock_bdev;
1830 }
1831 if (value)
1832 ret = blk_trace_setup_queue(q, bdev);
1833 else
1834 ret = blk_trace_remove_queue(q);
1835 goto out_unlock_bdev;
1836 }
1837
1838 ret = 0;
1839 if (q->blk_trace == NULL)
1840 ret = blk_trace_setup_queue(q, bdev);
1841
1842 if (ret == 0) {
1843 if (attr == &dev_attr_act_mask)
1844 q->blk_trace->act_mask = value;
1845 else if (attr == &dev_attr_pid)
1846 q->blk_trace->pid = value;
1847 else if (attr == &dev_attr_start_lba)
1848 q->blk_trace->start_lba = value;
1849 else if (attr == &dev_attr_end_lba)
1850 q->blk_trace->end_lba = value;
1851 }
1852
1853out_unlock_bdev:
1854 mutex_unlock(&q->blk_trace_mutex);
1855out_bdput:
1856 bdput(bdev);
1857out:
1858 return ret ? ret : count;
1859}
1860
1861int blk_trace_init_sysfs(struct device *dev)
1862{
1863 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1864}
1865
1866void blk_trace_remove_sysfs(struct device *dev)
1867{
1868 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1869}
1870
1871#endif /* CONFIG_BLK_DEV_IO_TRACE */
1872
1873#ifdef CONFIG_EVENT_TRACING
1874
1875void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
1876{
1877 int i = 0;
1878
1879 if (op & REQ_PREFLUSH)
1880 rwbs[i++] = 'F';
1881
1882 switch (op & REQ_OP_MASK) {
1883 case REQ_OP_WRITE:
1884 case REQ_OP_WRITE_SAME:
1885 rwbs[i++] = 'W';
1886 break;
1887 case REQ_OP_DISCARD:
1888 rwbs[i++] = 'D';
1889 break;
1890 case REQ_OP_SECURE_ERASE:
1891 rwbs[i++] = 'D';
1892 rwbs[i++] = 'E';
1893 break;
1894 case REQ_OP_FLUSH:
1895 rwbs[i++] = 'F';
1896 break;
1897 case REQ_OP_READ:
1898 rwbs[i++] = 'R';
1899 break;
1900 default:
1901 rwbs[i++] = 'N';
1902 }
1903
1904 if (op & REQ_FUA)
1905 rwbs[i++] = 'F';
1906 if (op & REQ_RAHEAD)
1907 rwbs[i++] = 'A';
1908 if (op & REQ_SYNC)
1909 rwbs[i++] = 'S';
1910 if (op & REQ_META)
1911 rwbs[i++] = 'M';
1912
1913 rwbs[i] = '\0';
1914}
1915EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1916
1917#endif /* CONFIG_EVENT_TRACING */
1918
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
4 *
5 */
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/kernel.h>
10#include <linux/blkdev.h>
11#include <linux/blktrace_api.h>
12#include <linux/percpu.h>
13#include <linux/init.h>
14#include <linux/mutex.h>
15#include <linux/slab.h>
16#include <linux/debugfs.h>
17#include <linux/export.h>
18#include <linux/time.h>
19#include <linux/uaccess.h>
20#include <linux/list.h>
21#include <linux/blk-cgroup.h>
22
23#include "../../block/blk.h"
24
25#include <trace/events/block.h>
26
27#include "trace_output.h"
28
29#ifdef CONFIG_BLK_DEV_IO_TRACE
30
31static unsigned int blktrace_seq __read_mostly = 1;
32
33static struct trace_array *blk_tr;
34static bool blk_tracer_enabled __read_mostly;
35
36static LIST_HEAD(running_trace_list);
37static __cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(running_trace_lock);
38
39/* Select an alternative, minimalistic output than the original one */
40#define TRACE_BLK_OPT_CLASSIC 0x1
41#define TRACE_BLK_OPT_CGROUP 0x2
42#define TRACE_BLK_OPT_CGNAME 0x4
43
44static struct tracer_opt blk_tracer_opts[] = {
45 /* Default disable the minimalistic output */
46 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
47#ifdef CONFIG_BLK_CGROUP
48 { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
49 { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
50#endif
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 DEFINE_MUTEX(blk_probe_mutex);
61static int blk_probes_ref;
62
63static void blk_register_tracepoints(void);
64static void blk_unregister_tracepoints(void);
65
66/*
67 * Send out a notify message.
68 */
69static void trace_note(struct blk_trace *bt, pid_t pid, int action,
70 const void *data, size_t len, u64 cgid)
71{
72 struct blk_io_trace *t;
73 struct ring_buffer_event *event = NULL;
74 struct trace_buffer *buffer = NULL;
75 unsigned int trace_ctx = 0;
76 int cpu = smp_processor_id();
77 bool blk_tracer = blk_tracer_enabled;
78 ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
79
80 if (blk_tracer) {
81 buffer = blk_tr->array_buffer.buffer;
82 trace_ctx = tracing_gen_ctx_flags(0);
83 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
84 sizeof(*t) + len + cgid_len,
85 trace_ctx);
86 if (!event)
87 return;
88 t = ring_buffer_event_data(event);
89 goto record_it;
90 }
91
92 if (!bt->rchan)
93 return;
94
95 t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len);
96 if (t) {
97 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
98 t->time = ktime_to_ns(ktime_get());
99record_it:
100 t->device = bt->dev;
101 t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
102 t->pid = pid;
103 t->cpu = cpu;
104 t->pdu_len = len + cgid_len;
105 if (cgid_len)
106 memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
107 memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
108
109 if (blk_tracer)
110 trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
111 }
112}
113
114/*
115 * Send out a notify for this process, if we haven't done so since a trace
116 * started
117 */
118static void trace_note_tsk(struct task_struct *tsk)
119{
120 unsigned long flags;
121 struct blk_trace *bt;
122
123 tsk->btrace_seq = blktrace_seq;
124 raw_spin_lock_irqsave(&running_trace_lock, flags);
125 list_for_each_entry(bt, &running_trace_list, running_list) {
126 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
127 sizeof(tsk->comm), 0);
128 }
129 raw_spin_unlock_irqrestore(&running_trace_lock, flags);
130}
131
132static void trace_note_time(struct blk_trace *bt)
133{
134 struct timespec64 now;
135 unsigned long flags;
136 u32 words[2];
137
138 /* need to check user space to see if this breaks in y2038 or y2106 */
139 ktime_get_real_ts64(&now);
140 words[0] = (u32)now.tv_sec;
141 words[1] = now.tv_nsec;
142
143 local_irq_save(flags);
144 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), 0);
145 local_irq_restore(flags);
146}
147
148void __blk_trace_note_message(struct blk_trace *bt,
149 struct cgroup_subsys_state *css, const char *fmt, ...)
150{
151 int n;
152 va_list args;
153 unsigned long flags;
154 char *buf;
155 u64 cgid = 0;
156
157 if (unlikely(bt->trace_state != Blktrace_running &&
158 !blk_tracer_enabled))
159 return;
160
161 /*
162 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
163 * message to the trace.
164 */
165 if (!(bt->act_mask & BLK_TC_NOTIFY))
166 return;
167
168 local_irq_save(flags);
169 buf = this_cpu_ptr(bt->msg_data);
170 va_start(args, fmt);
171 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
172 va_end(args);
173
174#ifdef CONFIG_BLK_CGROUP
175 if (css && (blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
176 cgid = cgroup_id(css->cgroup);
177 else
178 cgid = 1;
179#endif
180 trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n, cgid);
181 local_irq_restore(flags);
182}
183EXPORT_SYMBOL_GPL(__blk_trace_note_message);
184
185static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
186 pid_t pid)
187{
188 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
189 return 1;
190 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
191 return 1;
192 if (bt->pid && pid != bt->pid)
193 return 1;
194
195 return 0;
196}
197
198/*
199 * Data direction bit lookup
200 */
201static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
202 BLK_TC_ACT(BLK_TC_WRITE) };
203
204#define BLK_TC_RAHEAD BLK_TC_AHEAD
205#define BLK_TC_PREFLUSH BLK_TC_FLUSH
206
207/* The ilog2() calls fall out because they're constant */
208#define MASK_TC_BIT(rw, __name) ((__force u32)(rw & REQ_ ## __name) << \
209 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
210
211/*
212 * The worker for the various blk_add_trace*() types. Fills out a
213 * blk_io_trace structure and places it in a per-cpu subbuffer.
214 */
215static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
216 const blk_opf_t opf, u32 what, int error,
217 int pdu_len, void *pdu_data, u64 cgid)
218{
219 struct task_struct *tsk = current;
220 struct ring_buffer_event *event = NULL;
221 struct trace_buffer *buffer = NULL;
222 struct blk_io_trace *t;
223 unsigned long flags = 0;
224 unsigned long *sequence;
225 unsigned int trace_ctx = 0;
226 pid_t pid;
227 int cpu;
228 bool blk_tracer = blk_tracer_enabled;
229 ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
230 const enum req_op op = opf & REQ_OP_MASK;
231
232 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
233 return;
234
235 what |= ddir_act[op_is_write(op) ? WRITE : READ];
236 what |= MASK_TC_BIT(opf, SYNC);
237 what |= MASK_TC_BIT(opf, RAHEAD);
238 what |= MASK_TC_BIT(opf, META);
239 what |= MASK_TC_BIT(opf, PREFLUSH);
240 what |= MASK_TC_BIT(opf, FUA);
241 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
242 what |= BLK_TC_ACT(BLK_TC_DISCARD);
243 if (op == REQ_OP_FLUSH)
244 what |= BLK_TC_ACT(BLK_TC_FLUSH);
245 if (cgid)
246 what |= __BLK_TA_CGROUP;
247
248 pid = tsk->pid;
249 if (act_log_check(bt, what, sector, pid))
250 return;
251 cpu = raw_smp_processor_id();
252
253 if (blk_tracer) {
254 tracing_record_cmdline(current);
255
256 buffer = blk_tr->array_buffer.buffer;
257 trace_ctx = tracing_gen_ctx_flags(0);
258 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
259 sizeof(*t) + pdu_len + cgid_len,
260 trace_ctx);
261 if (!event)
262 return;
263 t = ring_buffer_event_data(event);
264 goto record_it;
265 }
266
267 if (unlikely(tsk->btrace_seq != blktrace_seq))
268 trace_note_tsk(tsk);
269
270 /*
271 * A word about the locking here - we disable interrupts to reserve
272 * some space in the relay per-cpu buffer, to prevent an irq
273 * from coming in and stepping on our toes.
274 */
275 local_irq_save(flags);
276 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
277 if (t) {
278 sequence = per_cpu_ptr(bt->sequence, cpu);
279
280 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
281 t->sequence = ++(*sequence);
282 t->time = ktime_to_ns(ktime_get());
283record_it:
284 /*
285 * These two are not needed in ftrace as they are in the
286 * generic trace_entry, filled by tracing_generic_entry_update,
287 * but for the trace_event->bin() synthesizer benefit we do it
288 * here too.
289 */
290 t->cpu = cpu;
291 t->pid = pid;
292
293 t->sector = sector;
294 t->bytes = bytes;
295 t->action = what;
296 t->device = bt->dev;
297 t->error = error;
298 t->pdu_len = pdu_len + cgid_len;
299
300 if (cgid_len)
301 memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
302 if (pdu_len)
303 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
304
305 if (blk_tracer) {
306 trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
307 return;
308 }
309 }
310
311 local_irq_restore(flags);
312}
313
314static void blk_trace_free(struct request_queue *q, struct blk_trace *bt)
315{
316 relay_close(bt->rchan);
317
318 /*
319 * If 'bt->dir' is not set, then both 'dropped' and 'msg' are created
320 * under 'q->debugfs_dir', thus lookup and remove them.
321 */
322 if (!bt->dir) {
323 debugfs_lookup_and_remove("dropped", q->debugfs_dir);
324 debugfs_lookup_and_remove("msg", q->debugfs_dir);
325 } else {
326 debugfs_remove(bt->dir);
327 }
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 int blk_trace_start(struct blk_trace *bt)
350{
351 if (bt->trace_state != Blktrace_setup &&
352 bt->trace_state != Blktrace_stopped)
353 return -EINVAL;
354
355 blktrace_seq++;
356 smp_mb();
357 bt->trace_state = Blktrace_running;
358 raw_spin_lock_irq(&running_trace_lock);
359 list_add(&bt->running_list, &running_trace_list);
360 raw_spin_unlock_irq(&running_trace_lock);
361 trace_note_time(bt);
362
363 return 0;
364}
365
366static int blk_trace_stop(struct blk_trace *bt)
367{
368 if (bt->trace_state != Blktrace_running)
369 return -EINVAL;
370
371 bt->trace_state = Blktrace_stopped;
372 raw_spin_lock_irq(&running_trace_lock);
373 list_del_init(&bt->running_list);
374 raw_spin_unlock_irq(&running_trace_lock);
375 relay_flush(bt->rchan);
376
377 return 0;
378}
379
380static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt)
381{
382 blk_trace_stop(bt);
383 synchronize_rcu();
384 blk_trace_free(q, bt);
385 put_probe_ref();
386}
387
388static int __blk_trace_remove(struct request_queue *q)
389{
390 struct blk_trace *bt;
391
392 bt = rcu_replace_pointer(q->blk_trace, NULL,
393 lockdep_is_held(&q->debugfs_mutex));
394 if (!bt)
395 return -EINVAL;
396
397 blk_trace_cleanup(q, bt);
398
399 return 0;
400}
401
402int blk_trace_remove(struct request_queue *q)
403{
404 int ret;
405
406 mutex_lock(&q->debugfs_mutex);
407 ret = __blk_trace_remove(q);
408 mutex_unlock(&q->debugfs_mutex);
409
410 return ret;
411}
412EXPORT_SYMBOL_GPL(blk_trace_remove);
413
414static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
415 size_t count, loff_t *ppos)
416{
417 struct blk_trace *bt = filp->private_data;
418 char buf[16];
419
420 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
421
422 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
423}
424
425static const struct file_operations blk_dropped_fops = {
426 .owner = THIS_MODULE,
427 .open = simple_open,
428 .read = blk_dropped_read,
429 .llseek = default_llseek,
430};
431
432static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
433 size_t count, loff_t *ppos)
434{
435 char *msg;
436 struct blk_trace *bt;
437
438 if (count >= BLK_TN_MAX_MSG)
439 return -EINVAL;
440
441 msg = memdup_user_nul(buffer, count);
442 if (IS_ERR(msg))
443 return PTR_ERR(msg);
444
445 bt = filp->private_data;
446 __blk_trace_note_message(bt, NULL, "%s", msg);
447 kfree(msg);
448
449 return count;
450}
451
452static const struct file_operations blk_msg_fops = {
453 .owner = THIS_MODULE,
454 .open = simple_open,
455 .write = blk_msg_write,
456 .llseek = noop_llseek,
457};
458
459/*
460 * Keep track of how many times we encountered a full subbuffer, to aid
461 * the user space app in telling how many lost events there were.
462 */
463static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
464 void *prev_subbuf, size_t prev_padding)
465{
466 struct blk_trace *bt;
467
468 if (!relay_buf_full(buf))
469 return 1;
470
471 bt = buf->chan->private_data;
472 atomic_inc(&bt->dropped);
473 return 0;
474}
475
476static int blk_remove_buf_file_callback(struct dentry *dentry)
477{
478 debugfs_remove(dentry);
479
480 return 0;
481}
482
483static struct dentry *blk_create_buf_file_callback(const char *filename,
484 struct dentry *parent,
485 umode_t mode,
486 struct rchan_buf *buf,
487 int *is_global)
488{
489 return debugfs_create_file(filename, mode, parent, buf,
490 &relay_file_operations);
491}
492
493static const struct rchan_callbacks blk_relay_callbacks = {
494 .subbuf_start = blk_subbuf_start_callback,
495 .create_buf_file = blk_create_buf_file_callback,
496 .remove_buf_file = blk_remove_buf_file_callback,
497};
498
499static void blk_trace_setup_lba(struct blk_trace *bt,
500 struct block_device *bdev)
501{
502 if (bdev) {
503 bt->start_lba = bdev->bd_start_sect;
504 bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev);
505 } else {
506 bt->start_lba = 0;
507 bt->end_lba = -1ULL;
508 }
509}
510
511/*
512 * Setup everything required to start tracing
513 */
514static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
515 struct block_device *bdev,
516 struct blk_user_trace_setup *buts)
517{
518 struct blk_trace *bt = NULL;
519 struct dentry *dir = NULL;
520 int ret;
521
522 lockdep_assert_held(&q->debugfs_mutex);
523
524 if (!buts->buf_size || !buts->buf_nr)
525 return -EINVAL;
526
527 strscpy_pad(buts->name, name, BLKTRACE_BDEV_SIZE);
528
529 /*
530 * some device names have larger paths - convert the slashes
531 * to underscores for this to work as expected
532 */
533 strreplace(buts->name, '/', '_');
534
535 /*
536 * bdev can be NULL, as with scsi-generic, this is a helpful as
537 * we can be.
538 */
539 if (rcu_dereference_protected(q->blk_trace,
540 lockdep_is_held(&q->debugfs_mutex))) {
541 pr_warn("Concurrent blktraces are not allowed on %s\n",
542 buts->name);
543 return -EBUSY;
544 }
545
546 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
547 if (!bt)
548 return -ENOMEM;
549
550 ret = -ENOMEM;
551 bt->sequence = alloc_percpu(unsigned long);
552 if (!bt->sequence)
553 goto err;
554
555 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
556 if (!bt->msg_data)
557 goto err;
558
559 /*
560 * When tracing the whole disk reuse the existing debugfs directory
561 * created by the block layer on init. For partitions block devices,
562 * and scsi-generic block devices we create a temporary new debugfs
563 * directory that will be removed once the trace ends.
564 */
565 if (bdev && !bdev_is_partition(bdev))
566 dir = q->debugfs_dir;
567 else
568 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
569
570 /*
571 * As blktrace relies on debugfs for its interface the debugfs directory
572 * is required, contrary to the usual mantra of not checking for debugfs
573 * files or directories.
574 */
575 if (IS_ERR_OR_NULL(dir)) {
576 pr_warn("debugfs_dir not present for %s so skipping\n",
577 buts->name);
578 ret = -ENOENT;
579 goto err;
580 }
581
582 bt->dev = dev;
583 atomic_set(&bt->dropped, 0);
584 INIT_LIST_HEAD(&bt->running_list);
585
586 ret = -EIO;
587 debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
588 debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
589
590 bt->rchan = relay_open("trace", dir, buts->buf_size,
591 buts->buf_nr, &blk_relay_callbacks, bt);
592 if (!bt->rchan)
593 goto err;
594
595 bt->act_mask = buts->act_mask;
596 if (!bt->act_mask)
597 bt->act_mask = (u16) -1;
598
599 blk_trace_setup_lba(bt, bdev);
600
601 /* overwrite with user settings */
602 if (buts->start_lba)
603 bt->start_lba = buts->start_lba;
604 if (buts->end_lba)
605 bt->end_lba = buts->end_lba;
606
607 bt->pid = buts->pid;
608 bt->trace_state = Blktrace_setup;
609
610 rcu_assign_pointer(q->blk_trace, bt);
611 get_probe_ref();
612
613 ret = 0;
614err:
615 if (ret)
616 blk_trace_free(q, bt);
617 return ret;
618}
619
620static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
621 struct block_device *bdev, char __user *arg)
622{
623 struct blk_user_trace_setup buts;
624 int ret;
625
626 ret = copy_from_user(&buts, arg, sizeof(buts));
627 if (ret)
628 return -EFAULT;
629
630 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
631 if (ret)
632 return ret;
633
634 if (copy_to_user(arg, &buts, sizeof(buts))) {
635 __blk_trace_remove(q);
636 return -EFAULT;
637 }
638 return 0;
639}
640
641int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
642 struct block_device *bdev,
643 char __user *arg)
644{
645 int ret;
646
647 mutex_lock(&q->debugfs_mutex);
648 ret = __blk_trace_setup(q, name, dev, bdev, arg);
649 mutex_unlock(&q->debugfs_mutex);
650
651 return ret;
652}
653EXPORT_SYMBOL_GPL(blk_trace_setup);
654
655#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
656static int compat_blk_trace_setup(struct request_queue *q, char *name,
657 dev_t dev, struct block_device *bdev,
658 char __user *arg)
659{
660 struct blk_user_trace_setup buts;
661 struct compat_blk_user_trace_setup cbuts;
662 int ret;
663
664 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
665 return -EFAULT;
666
667 buts = (struct blk_user_trace_setup) {
668 .act_mask = cbuts.act_mask,
669 .buf_size = cbuts.buf_size,
670 .buf_nr = cbuts.buf_nr,
671 .start_lba = cbuts.start_lba,
672 .end_lba = cbuts.end_lba,
673 .pid = cbuts.pid,
674 };
675
676 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
677 if (ret)
678 return ret;
679
680 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
681 __blk_trace_remove(q);
682 return -EFAULT;
683 }
684
685 return 0;
686}
687#endif
688
689static int __blk_trace_startstop(struct request_queue *q, int start)
690{
691 struct blk_trace *bt;
692
693 bt = rcu_dereference_protected(q->blk_trace,
694 lockdep_is_held(&q->debugfs_mutex));
695 if (bt == NULL)
696 return -EINVAL;
697
698 if (start)
699 return blk_trace_start(bt);
700 else
701 return blk_trace_stop(bt);
702}
703
704int blk_trace_startstop(struct request_queue *q, int start)
705{
706 int ret;
707
708 mutex_lock(&q->debugfs_mutex);
709 ret = __blk_trace_startstop(q, start);
710 mutex_unlock(&q->debugfs_mutex);
711
712 return ret;
713}
714EXPORT_SYMBOL_GPL(blk_trace_startstop);
715
716/*
717 * When reading or writing the blktrace sysfs files, the references to the
718 * opened sysfs or device files should prevent the underlying block device
719 * from being removed. So no further delete protection is really needed.
720 */
721
722/**
723 * blk_trace_ioctl - handle the ioctls associated with tracing
724 * @bdev: the block device
725 * @cmd: the ioctl cmd
726 * @arg: the argument data, if any
727 *
728 **/
729int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
730{
731 struct request_queue *q = bdev_get_queue(bdev);
732 int ret, start = 0;
733 char b[BDEVNAME_SIZE];
734
735 mutex_lock(&q->debugfs_mutex);
736
737 switch (cmd) {
738 case BLKTRACESETUP:
739 snprintf(b, sizeof(b), "%pg", bdev);
740 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
741 break;
742#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
743 case BLKTRACESETUP32:
744 snprintf(b, sizeof(b), "%pg", bdev);
745 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
746 break;
747#endif
748 case BLKTRACESTART:
749 start = 1;
750 fallthrough;
751 case BLKTRACESTOP:
752 ret = __blk_trace_startstop(q, start);
753 break;
754 case BLKTRACETEARDOWN:
755 ret = __blk_trace_remove(q);
756 break;
757 default:
758 ret = -ENOTTY;
759 break;
760 }
761
762 mutex_unlock(&q->debugfs_mutex);
763 return ret;
764}
765
766/**
767 * blk_trace_shutdown - stop and cleanup trace structures
768 * @q: the request queue associated with the device
769 *
770 **/
771void blk_trace_shutdown(struct request_queue *q)
772{
773 if (rcu_dereference_protected(q->blk_trace,
774 lockdep_is_held(&q->debugfs_mutex)))
775 __blk_trace_remove(q);
776}
777
778#ifdef CONFIG_BLK_CGROUP
779static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
780{
781 struct cgroup_subsys_state *blkcg_css;
782 struct blk_trace *bt;
783
784 /* We don't use the 'bt' value here except as an optimization... */
785 bt = rcu_dereference_protected(q->blk_trace, 1);
786 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
787 return 0;
788
789 blkcg_css = bio_blkcg_css(bio);
790 if (!blkcg_css)
791 return 0;
792 return cgroup_id(blkcg_css->cgroup);
793}
794#else
795static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
796{
797 return 0;
798}
799#endif
800
801static u64
802blk_trace_request_get_cgid(struct request *rq)
803{
804 if (!rq->bio)
805 return 0;
806 /* Use the first bio */
807 return blk_trace_bio_get_cgid(rq->q, rq->bio);
808}
809
810/*
811 * blktrace probes
812 */
813
814/**
815 * blk_add_trace_rq - Add a trace for a request oriented action
816 * @rq: the source request
817 * @error: return status to log
818 * @nr_bytes: number of completed bytes
819 * @what: the action
820 * @cgid: the cgroup info
821 *
822 * Description:
823 * Records an action against a request. Will log the bio offset + size.
824 *
825 **/
826static void blk_add_trace_rq(struct request *rq, blk_status_t error,
827 unsigned int nr_bytes, u32 what, u64 cgid)
828{
829 struct blk_trace *bt;
830
831 rcu_read_lock();
832 bt = rcu_dereference(rq->q->blk_trace);
833 if (likely(!bt)) {
834 rcu_read_unlock();
835 return;
836 }
837
838 if (blk_rq_is_passthrough(rq))
839 what |= BLK_TC_ACT(BLK_TC_PC);
840 else
841 what |= BLK_TC_ACT(BLK_TC_FS);
842
843 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, rq->cmd_flags,
844 what, blk_status_to_errno(error), 0, NULL, cgid);
845 rcu_read_unlock();
846}
847
848static void blk_add_trace_rq_insert(void *ignore, struct request *rq)
849{
850 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
851 blk_trace_request_get_cgid(rq));
852}
853
854static void blk_add_trace_rq_issue(void *ignore, struct request *rq)
855{
856 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
857 blk_trace_request_get_cgid(rq));
858}
859
860static void blk_add_trace_rq_merge(void *ignore, struct request *rq)
861{
862 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
863 blk_trace_request_get_cgid(rq));
864}
865
866static void blk_add_trace_rq_requeue(void *ignore, struct request *rq)
867{
868 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
869 blk_trace_request_get_cgid(rq));
870}
871
872static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
873 blk_status_t error, unsigned int nr_bytes)
874{
875 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
876 blk_trace_request_get_cgid(rq));
877}
878
879/**
880 * blk_add_trace_bio - Add a trace for a bio oriented action
881 * @q: queue the io is for
882 * @bio: the source bio
883 * @what: the action
884 * @error: error, if any
885 *
886 * Description:
887 * Records an action against a bio. Will log the bio offset + size.
888 *
889 **/
890static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
891 u32 what, int error)
892{
893 struct blk_trace *bt;
894
895 rcu_read_lock();
896 bt = rcu_dereference(q->blk_trace);
897 if (likely(!bt)) {
898 rcu_read_unlock();
899 return;
900 }
901
902 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
903 bio->bi_opf, what, error, 0, NULL,
904 blk_trace_bio_get_cgid(q, bio));
905 rcu_read_unlock();
906}
907
908static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio)
909{
910 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0);
911}
912
913static void blk_add_trace_bio_complete(void *ignore,
914 struct request_queue *q, struct bio *bio)
915{
916 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
917 blk_status_to_errno(bio->bi_status));
918}
919
920static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio)
921{
922 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE,
923 0);
924}
925
926static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio)
927{
928 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE,
929 0);
930}
931
932static void blk_add_trace_bio_queue(void *ignore, struct bio *bio)
933{
934 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0);
935}
936
937static void blk_add_trace_getrq(void *ignore, struct bio *bio)
938{
939 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0);
940}
941
942static void blk_add_trace_plug(void *ignore, struct request_queue *q)
943{
944 struct blk_trace *bt;
945
946 rcu_read_lock();
947 bt = rcu_dereference(q->blk_trace);
948 if (bt)
949 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
950 rcu_read_unlock();
951}
952
953static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
954 unsigned int depth, bool explicit)
955{
956 struct blk_trace *bt;
957
958 rcu_read_lock();
959 bt = rcu_dereference(q->blk_trace);
960 if (bt) {
961 __be64 rpdu = cpu_to_be64(depth);
962 u32 what;
963
964 if (explicit)
965 what = BLK_TA_UNPLUG_IO;
966 else
967 what = BLK_TA_UNPLUG_TIMER;
968
969 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
970 }
971 rcu_read_unlock();
972}
973
974static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
975{
976 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
977 struct blk_trace *bt;
978
979 rcu_read_lock();
980 bt = rcu_dereference(q->blk_trace);
981 if (bt) {
982 __be64 rpdu = cpu_to_be64(pdu);
983
984 __blk_add_trace(bt, bio->bi_iter.bi_sector,
985 bio->bi_iter.bi_size, bio->bi_opf, BLK_TA_SPLIT,
986 blk_status_to_errno(bio->bi_status),
987 sizeof(rpdu), &rpdu,
988 blk_trace_bio_get_cgid(q, bio));
989 }
990 rcu_read_unlock();
991}
992
993/**
994 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
995 * @ignore: trace callback data parameter (not used)
996 * @bio: the source bio
997 * @dev: source device
998 * @from: source sector
999 *
1000 * Called after a bio is remapped to a different device and/or sector.
1001 **/
1002static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev,
1003 sector_t from)
1004{
1005 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
1006 struct blk_trace *bt;
1007 struct blk_io_trace_remap r;
1008
1009 rcu_read_lock();
1010 bt = rcu_dereference(q->blk_trace);
1011 if (likely(!bt)) {
1012 rcu_read_unlock();
1013 return;
1014 }
1015
1016 r.device_from = cpu_to_be32(dev);
1017 r.device_to = cpu_to_be32(bio_dev(bio));
1018 r.sector_from = cpu_to_be64(from);
1019
1020 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1021 bio->bi_opf, BLK_TA_REMAP,
1022 blk_status_to_errno(bio->bi_status),
1023 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1024 rcu_read_unlock();
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 * @rq: the source request
1031 * @dev: target device
1032 * @from: source sector
1033 *
1034 * Description:
1035 * Device mapper remaps request to other devices.
1036 * Add a trace for that action.
1037 *
1038 **/
1039static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev,
1040 sector_t from)
1041{
1042 struct blk_trace *bt;
1043 struct blk_io_trace_remap r;
1044
1045 rcu_read_lock();
1046 bt = rcu_dereference(rq->q->blk_trace);
1047 if (likely(!bt)) {
1048 rcu_read_unlock();
1049 return;
1050 }
1051
1052 r.device_from = cpu_to_be32(dev);
1053 r.device_to = cpu_to_be32(disk_devt(rq->q->disk));
1054 r.sector_from = cpu_to_be64(from);
1055
1056 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1057 rq->cmd_flags, BLK_TA_REMAP, 0,
1058 sizeof(r), &r, blk_trace_request_get_cgid(rq));
1059 rcu_read_unlock();
1060}
1061
1062/**
1063 * blk_add_driver_data - Add binary message with driver-specific data
1064 * @rq: io request
1065 * @data: driver-specific data
1066 * @len: length of driver-specific data
1067 *
1068 * Description:
1069 * Some drivers might want to write driver-specific data per request.
1070 *
1071 **/
1072void blk_add_driver_data(struct request *rq, void *data, size_t len)
1073{
1074 struct blk_trace *bt;
1075
1076 rcu_read_lock();
1077 bt = rcu_dereference(rq->q->blk_trace);
1078 if (likely(!bt)) {
1079 rcu_read_unlock();
1080 return;
1081 }
1082
1083 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0,
1084 BLK_TA_DRV_DATA, 0, len, data,
1085 blk_trace_request_get_cgid(rq));
1086 rcu_read_unlock();
1087}
1088EXPORT_SYMBOL_GPL(blk_add_driver_data);
1089
1090static void blk_register_tracepoints(void)
1091{
1092 int ret;
1093
1094 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1095 WARN_ON(ret);
1096 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1097 WARN_ON(ret);
1098 ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1099 WARN_ON(ret);
1100 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1101 WARN_ON(ret);
1102 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1103 WARN_ON(ret);
1104 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1105 WARN_ON(ret);
1106 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1107 WARN_ON(ret);
1108 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1109 WARN_ON(ret);
1110 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1111 WARN_ON(ret);
1112 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1113 WARN_ON(ret);
1114 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1115 WARN_ON(ret);
1116 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1117 WARN_ON(ret);
1118 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1119 WARN_ON(ret);
1120 ret = register_trace_block_split(blk_add_trace_split, NULL);
1121 WARN_ON(ret);
1122 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1123 WARN_ON(ret);
1124 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1125 WARN_ON(ret);
1126}
1127
1128static void blk_unregister_tracepoints(void)
1129{
1130 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1131 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1132 unregister_trace_block_split(blk_add_trace_split, NULL);
1133 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1134 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1135 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1136 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1137 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1138 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1139 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1140 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1141 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1142 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1143 unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1144 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1145 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1146
1147 tracepoint_synchronize_unregister();
1148}
1149
1150/*
1151 * struct blk_io_tracer formatting routines
1152 */
1153
1154static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1155{
1156 int i = 0;
1157 int tc = t->action >> BLK_TC_SHIFT;
1158
1159 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1160 rwbs[i++] = 'N';
1161 goto out;
1162 }
1163
1164 if (tc & BLK_TC_FLUSH)
1165 rwbs[i++] = 'F';
1166
1167 if (tc & BLK_TC_DISCARD)
1168 rwbs[i++] = 'D';
1169 else if (tc & BLK_TC_WRITE)
1170 rwbs[i++] = 'W';
1171 else if (t->bytes)
1172 rwbs[i++] = 'R';
1173 else
1174 rwbs[i++] = 'N';
1175
1176 if (tc & BLK_TC_FUA)
1177 rwbs[i++] = 'F';
1178 if (tc & BLK_TC_AHEAD)
1179 rwbs[i++] = 'A';
1180 if (tc & BLK_TC_SYNC)
1181 rwbs[i++] = 'S';
1182 if (tc & BLK_TC_META)
1183 rwbs[i++] = 'M';
1184out:
1185 rwbs[i] = '\0';
1186}
1187
1188static inline
1189const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1190{
1191 return (const struct blk_io_trace *)ent;
1192}
1193
1194static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1195{
1196 return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
1197}
1198
1199static inline u64 t_cgid(const struct trace_entry *ent)
1200{
1201 return *(u64 *)(te_blk_io_trace(ent) + 1);
1202}
1203
1204static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1205{
1206 return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
1207}
1208
1209static inline u32 t_action(const struct trace_entry *ent)
1210{
1211 return te_blk_io_trace(ent)->action;
1212}
1213
1214static inline u32 t_bytes(const struct trace_entry *ent)
1215{
1216 return te_blk_io_trace(ent)->bytes;
1217}
1218
1219static inline u32 t_sec(const struct trace_entry *ent)
1220{
1221 return te_blk_io_trace(ent)->bytes >> 9;
1222}
1223
1224static inline unsigned long long t_sector(const struct trace_entry *ent)
1225{
1226 return te_blk_io_trace(ent)->sector;
1227}
1228
1229static inline __u16 t_error(const struct trace_entry *ent)
1230{
1231 return te_blk_io_trace(ent)->error;
1232}
1233
1234static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1235{
1236 const __be64 *val = pdu_start(ent, has_cg);
1237 return be64_to_cpu(*val);
1238}
1239
1240typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1241 bool has_cg);
1242
1243static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1244 bool has_cg)
1245{
1246 char rwbs[RWBS_LEN];
1247 unsigned long long ts = iter->ts;
1248 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1249 unsigned secs = (unsigned long)ts;
1250 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1251
1252 fill_rwbs(rwbs, t);
1253
1254 trace_seq_printf(&iter->seq,
1255 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1256 MAJOR(t->device), MINOR(t->device), iter->cpu,
1257 secs, nsec_rem, iter->ent->pid, act, rwbs);
1258}
1259
1260static void blk_log_action(struct trace_iterator *iter, const char *act,
1261 bool has_cg)
1262{
1263 char rwbs[RWBS_LEN];
1264 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1265
1266 fill_rwbs(rwbs, t);
1267 if (has_cg) {
1268 u64 id = t_cgid(iter->ent);
1269
1270 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1271 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1272
1273 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1274 sizeof(blkcg_name_buf));
1275 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1276 MAJOR(t->device), MINOR(t->device),
1277 blkcg_name_buf, act, rwbs);
1278 } else {
1279 /*
1280 * The cgid portion used to be "INO,GEN". Userland
1281 * builds a FILEID_INO32_GEN fid out of them and
1282 * opens the cgroup using open_by_handle_at(2).
1283 * While 32bit ino setups are still the same, 64bit
1284 * ones now use the 64bit ino as the whole ID and
1285 * no longer use generation.
1286 *
1287 * Regardless of the content, always output
1288 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
1289 * be mapped back to @id on both 64 and 32bit ino
1290 * setups. See __kernfs_fh_to_dentry().
1291 */
1292 trace_seq_printf(&iter->seq,
1293 "%3d,%-3d %llx,%-llx %2s %3s ",
1294 MAJOR(t->device), MINOR(t->device),
1295 id & U32_MAX, id >> 32, act, rwbs);
1296 }
1297 } else
1298 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1299 MAJOR(t->device), MINOR(t->device), act, rwbs);
1300}
1301
1302static void blk_log_dump_pdu(struct trace_seq *s,
1303 const struct trace_entry *ent, bool has_cg)
1304{
1305 const unsigned char *pdu_buf;
1306 int pdu_len;
1307 int i, end;
1308
1309 pdu_buf = pdu_start(ent, has_cg);
1310 pdu_len = pdu_real_len(ent, has_cg);
1311
1312 if (!pdu_len)
1313 return;
1314
1315 /* find the last zero that needs to be printed */
1316 for (end = pdu_len - 1; end >= 0; end--)
1317 if (pdu_buf[end])
1318 break;
1319 end++;
1320
1321 trace_seq_putc(s, '(');
1322
1323 for (i = 0; i < pdu_len; i++) {
1324
1325 trace_seq_printf(s, "%s%02x",
1326 i == 0 ? "" : " ", pdu_buf[i]);
1327
1328 /*
1329 * stop when the rest is just zeros and indicate so
1330 * with a ".." appended
1331 */
1332 if (i == end && end != pdu_len - 1) {
1333 trace_seq_puts(s, " ..) ");
1334 return;
1335 }
1336 }
1337
1338 trace_seq_puts(s, ") ");
1339}
1340
1341static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1342{
1343 char cmd[TASK_COMM_LEN];
1344
1345 trace_find_cmdline(ent->pid, cmd);
1346
1347 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1348 trace_seq_printf(s, "%u ", t_bytes(ent));
1349 blk_log_dump_pdu(s, ent, has_cg);
1350 trace_seq_printf(s, "[%s]\n", cmd);
1351 } else {
1352 if (t_sec(ent))
1353 trace_seq_printf(s, "%llu + %u [%s]\n",
1354 t_sector(ent), t_sec(ent), cmd);
1355 else
1356 trace_seq_printf(s, "[%s]\n", cmd);
1357 }
1358}
1359
1360static void blk_log_with_error(struct trace_seq *s,
1361 const struct trace_entry *ent, bool has_cg)
1362{
1363 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1364 blk_log_dump_pdu(s, ent, has_cg);
1365 trace_seq_printf(s, "[%d]\n", t_error(ent));
1366 } else {
1367 if (t_sec(ent))
1368 trace_seq_printf(s, "%llu + %u [%d]\n",
1369 t_sector(ent),
1370 t_sec(ent), t_error(ent));
1371 else
1372 trace_seq_printf(s, "%llu [%d]\n",
1373 t_sector(ent), t_error(ent));
1374 }
1375}
1376
1377static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1378{
1379 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1380
1381 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1382 t_sector(ent), t_sec(ent),
1383 MAJOR(be32_to_cpu(__r->device_from)),
1384 MINOR(be32_to_cpu(__r->device_from)),
1385 be64_to_cpu(__r->sector_from));
1386}
1387
1388static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1389{
1390 char cmd[TASK_COMM_LEN];
1391
1392 trace_find_cmdline(ent->pid, cmd);
1393
1394 trace_seq_printf(s, "[%s]\n", cmd);
1395}
1396
1397static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1398{
1399 char cmd[TASK_COMM_LEN];
1400
1401 trace_find_cmdline(ent->pid, cmd);
1402
1403 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1404}
1405
1406static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1407{
1408 char cmd[TASK_COMM_LEN];
1409
1410 trace_find_cmdline(ent->pid, cmd);
1411
1412 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1413 get_pdu_int(ent, has_cg), cmd);
1414}
1415
1416static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1417 bool has_cg)
1418{
1419
1420 trace_seq_putmem(s, pdu_start(ent, has_cg),
1421 pdu_real_len(ent, has_cg));
1422 trace_seq_putc(s, '\n');
1423}
1424
1425/*
1426 * struct tracer operations
1427 */
1428
1429static void blk_tracer_print_header(struct seq_file *m)
1430{
1431 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1432 return;
1433 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1434 "# | | | | | |\n");
1435}
1436
1437static void blk_tracer_start(struct trace_array *tr)
1438{
1439 blk_tracer_enabled = true;
1440}
1441
1442static int blk_tracer_init(struct trace_array *tr)
1443{
1444 blk_tr = tr;
1445 blk_tracer_start(tr);
1446 return 0;
1447}
1448
1449static void blk_tracer_stop(struct trace_array *tr)
1450{
1451 blk_tracer_enabled = false;
1452}
1453
1454static void blk_tracer_reset(struct trace_array *tr)
1455{
1456 blk_tracer_stop(tr);
1457}
1458
1459static const struct {
1460 const char *act[2];
1461 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1462 bool has_cg);
1463} what2act[] = {
1464 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1465 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1466 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1467 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1468 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1469 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1470 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1471 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1472 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1473 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1474 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1475 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1476 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1477 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1478 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1479};
1480
1481static enum print_line_t print_one_line(struct trace_iterator *iter,
1482 bool classic)
1483{
1484 struct trace_array *tr = iter->tr;
1485 struct trace_seq *s = &iter->seq;
1486 const struct blk_io_trace *t;
1487 u16 what;
1488 bool long_act;
1489 blk_log_action_t *log_action;
1490 bool has_cg;
1491
1492 t = te_blk_io_trace(iter->ent);
1493 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1494 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1495 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1496 has_cg = t->action & __BLK_TA_CGROUP;
1497
1498 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1499 log_action(iter, long_act ? "message" : "m", has_cg);
1500 blk_log_msg(s, iter->ent, has_cg);
1501 return trace_handle_return(s);
1502 }
1503
1504 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1505 trace_seq_printf(s, "Unknown action %x\n", what);
1506 else {
1507 log_action(iter, what2act[what].act[long_act], has_cg);
1508 what2act[what].print(s, iter->ent, has_cg);
1509 }
1510
1511 return trace_handle_return(s);
1512}
1513
1514static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1515 int flags, struct trace_event *event)
1516{
1517 return print_one_line(iter, false);
1518}
1519
1520static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1521{
1522 struct trace_seq *s = &iter->seq;
1523 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1524 const int offset = offsetof(struct blk_io_trace, sector);
1525 struct blk_io_trace old = {
1526 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1527 .time = iter->ts,
1528 };
1529
1530 trace_seq_putmem(s, &old, offset);
1531 trace_seq_putmem(s, &t->sector,
1532 sizeof(old) - offset + t->pdu_len);
1533}
1534
1535static enum print_line_t
1536blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1537 struct trace_event *event)
1538{
1539 blk_trace_synthesize_old_trace(iter);
1540
1541 return trace_handle_return(&iter->seq);
1542}
1543
1544static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1545{
1546 if ((iter->ent->type != TRACE_BLK) ||
1547 !(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1548 return TRACE_TYPE_UNHANDLED;
1549
1550 return print_one_line(iter, true);
1551}
1552
1553static int
1554blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1555{
1556 /* don't output context-info for blk_classic output */
1557 if (bit == TRACE_BLK_OPT_CLASSIC) {
1558 if (set)
1559 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1560 else
1561 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1562 }
1563 return 0;
1564}
1565
1566static struct tracer blk_tracer __read_mostly = {
1567 .name = "blk",
1568 .init = blk_tracer_init,
1569 .reset = blk_tracer_reset,
1570 .start = blk_tracer_start,
1571 .stop = blk_tracer_stop,
1572 .print_header = blk_tracer_print_header,
1573 .print_line = blk_tracer_print_line,
1574 .flags = &blk_tracer_flags,
1575 .set_flag = blk_tracer_set_flag,
1576};
1577
1578static struct trace_event_functions trace_blk_event_funcs = {
1579 .trace = blk_trace_event_print,
1580 .binary = blk_trace_event_print_binary,
1581};
1582
1583static struct trace_event trace_blk_event = {
1584 .type = TRACE_BLK,
1585 .funcs = &trace_blk_event_funcs,
1586};
1587
1588static int __init init_blk_tracer(void)
1589{
1590 if (!register_trace_event(&trace_blk_event)) {
1591 pr_warn("Warning: could not register block events\n");
1592 return 1;
1593 }
1594
1595 if (register_tracer(&blk_tracer) != 0) {
1596 pr_warn("Warning: could not register the block tracer\n");
1597 unregister_trace_event(&trace_blk_event);
1598 return 1;
1599 }
1600
1601 return 0;
1602}
1603
1604device_initcall(init_blk_tracer);
1605
1606static int blk_trace_remove_queue(struct request_queue *q)
1607{
1608 struct blk_trace *bt;
1609
1610 bt = rcu_replace_pointer(q->blk_trace, NULL,
1611 lockdep_is_held(&q->debugfs_mutex));
1612 if (bt == NULL)
1613 return -EINVAL;
1614
1615 blk_trace_stop(bt);
1616
1617 put_probe_ref();
1618 synchronize_rcu();
1619 blk_trace_free(q, bt);
1620 return 0;
1621}
1622
1623/*
1624 * Setup everything required to start tracing
1625 */
1626static int blk_trace_setup_queue(struct request_queue *q,
1627 struct block_device *bdev)
1628{
1629 struct blk_trace *bt = NULL;
1630 int ret = -ENOMEM;
1631
1632 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1633 if (!bt)
1634 return -ENOMEM;
1635
1636 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1637 if (!bt->msg_data)
1638 goto free_bt;
1639
1640 bt->dev = bdev->bd_dev;
1641 bt->act_mask = (u16)-1;
1642
1643 blk_trace_setup_lba(bt, bdev);
1644
1645 rcu_assign_pointer(q->blk_trace, bt);
1646 get_probe_ref();
1647 return 0;
1648
1649free_bt:
1650 blk_trace_free(q, bt);
1651 return ret;
1652}
1653
1654/*
1655 * sysfs interface to enable and configure tracing
1656 */
1657
1658static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1659 struct device_attribute *attr,
1660 char *buf);
1661static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1662 struct device_attribute *attr,
1663 const char *buf, size_t count);
1664#define BLK_TRACE_DEVICE_ATTR(_name) \
1665 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1666 sysfs_blk_trace_attr_show, \
1667 sysfs_blk_trace_attr_store)
1668
1669static BLK_TRACE_DEVICE_ATTR(enable);
1670static BLK_TRACE_DEVICE_ATTR(act_mask);
1671static BLK_TRACE_DEVICE_ATTR(pid);
1672static BLK_TRACE_DEVICE_ATTR(start_lba);
1673static BLK_TRACE_DEVICE_ATTR(end_lba);
1674
1675static struct attribute *blk_trace_attrs[] = {
1676 &dev_attr_enable.attr,
1677 &dev_attr_act_mask.attr,
1678 &dev_attr_pid.attr,
1679 &dev_attr_start_lba.attr,
1680 &dev_attr_end_lba.attr,
1681 NULL
1682};
1683
1684struct attribute_group blk_trace_attr_group = {
1685 .name = "trace",
1686 .attrs = blk_trace_attrs,
1687};
1688
1689static const struct {
1690 int mask;
1691 const char *str;
1692} mask_maps[] = {
1693 { BLK_TC_READ, "read" },
1694 { BLK_TC_WRITE, "write" },
1695 { BLK_TC_FLUSH, "flush" },
1696 { BLK_TC_SYNC, "sync" },
1697 { BLK_TC_QUEUE, "queue" },
1698 { BLK_TC_REQUEUE, "requeue" },
1699 { BLK_TC_ISSUE, "issue" },
1700 { BLK_TC_COMPLETE, "complete" },
1701 { BLK_TC_FS, "fs" },
1702 { BLK_TC_PC, "pc" },
1703 { BLK_TC_NOTIFY, "notify" },
1704 { BLK_TC_AHEAD, "ahead" },
1705 { BLK_TC_META, "meta" },
1706 { BLK_TC_DISCARD, "discard" },
1707 { BLK_TC_DRV_DATA, "drv_data" },
1708 { BLK_TC_FUA, "fua" },
1709};
1710
1711static int blk_trace_str2mask(const char *str)
1712{
1713 int i;
1714 int mask = 0;
1715 char *buf, *s, *token;
1716
1717 buf = kstrdup(str, GFP_KERNEL);
1718 if (buf == NULL)
1719 return -ENOMEM;
1720 s = strstrip(buf);
1721
1722 while (1) {
1723 token = strsep(&s, ",");
1724 if (token == NULL)
1725 break;
1726
1727 if (*token == '\0')
1728 continue;
1729
1730 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1731 if (strcasecmp(token, mask_maps[i].str) == 0) {
1732 mask |= mask_maps[i].mask;
1733 break;
1734 }
1735 }
1736 if (i == ARRAY_SIZE(mask_maps)) {
1737 mask = -EINVAL;
1738 break;
1739 }
1740 }
1741 kfree(buf);
1742
1743 return mask;
1744}
1745
1746static ssize_t blk_trace_mask2str(char *buf, int mask)
1747{
1748 int i;
1749 char *p = buf;
1750
1751 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1752 if (mask & mask_maps[i].mask) {
1753 p += sprintf(p, "%s%s",
1754 (p == buf) ? "" : ",", mask_maps[i].str);
1755 }
1756 }
1757 *p++ = '\n';
1758
1759 return p - buf;
1760}
1761
1762static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1763 struct device_attribute *attr,
1764 char *buf)
1765{
1766 struct block_device *bdev = dev_to_bdev(dev);
1767 struct request_queue *q = bdev_get_queue(bdev);
1768 struct blk_trace *bt;
1769 ssize_t ret = -ENXIO;
1770
1771 mutex_lock(&q->debugfs_mutex);
1772
1773 bt = rcu_dereference_protected(q->blk_trace,
1774 lockdep_is_held(&q->debugfs_mutex));
1775 if (attr == &dev_attr_enable) {
1776 ret = sprintf(buf, "%u\n", !!bt);
1777 goto out_unlock_bdev;
1778 }
1779
1780 if (bt == NULL)
1781 ret = sprintf(buf, "disabled\n");
1782 else if (attr == &dev_attr_act_mask)
1783 ret = blk_trace_mask2str(buf, bt->act_mask);
1784 else if (attr == &dev_attr_pid)
1785 ret = sprintf(buf, "%u\n", bt->pid);
1786 else if (attr == &dev_attr_start_lba)
1787 ret = sprintf(buf, "%llu\n", bt->start_lba);
1788 else if (attr == &dev_attr_end_lba)
1789 ret = sprintf(buf, "%llu\n", bt->end_lba);
1790
1791out_unlock_bdev:
1792 mutex_unlock(&q->debugfs_mutex);
1793 return ret;
1794}
1795
1796static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1797 struct device_attribute *attr,
1798 const char *buf, size_t count)
1799{
1800 struct block_device *bdev = dev_to_bdev(dev);
1801 struct request_queue *q = bdev_get_queue(bdev);
1802 struct blk_trace *bt;
1803 u64 value;
1804 ssize_t ret = -EINVAL;
1805
1806 if (count == 0)
1807 goto out;
1808
1809 if (attr == &dev_attr_act_mask) {
1810 if (kstrtoull(buf, 0, &value)) {
1811 /* Assume it is a list of trace category names */
1812 ret = blk_trace_str2mask(buf);
1813 if (ret < 0)
1814 goto out;
1815 value = ret;
1816 }
1817 } else {
1818 if (kstrtoull(buf, 0, &value))
1819 goto out;
1820 }
1821
1822 mutex_lock(&q->debugfs_mutex);
1823
1824 bt = rcu_dereference_protected(q->blk_trace,
1825 lockdep_is_held(&q->debugfs_mutex));
1826 if (attr == &dev_attr_enable) {
1827 if (!!value == !!bt) {
1828 ret = 0;
1829 goto out_unlock_bdev;
1830 }
1831 if (value)
1832 ret = blk_trace_setup_queue(q, bdev);
1833 else
1834 ret = blk_trace_remove_queue(q);
1835 goto out_unlock_bdev;
1836 }
1837
1838 ret = 0;
1839 if (bt == NULL) {
1840 ret = blk_trace_setup_queue(q, bdev);
1841 bt = rcu_dereference_protected(q->blk_trace,
1842 lockdep_is_held(&q->debugfs_mutex));
1843 }
1844
1845 if (ret == 0) {
1846 if (attr == &dev_attr_act_mask)
1847 bt->act_mask = value;
1848 else if (attr == &dev_attr_pid)
1849 bt->pid = value;
1850 else if (attr == &dev_attr_start_lba)
1851 bt->start_lba = value;
1852 else if (attr == &dev_attr_end_lba)
1853 bt->end_lba = value;
1854 }
1855
1856out_unlock_bdev:
1857 mutex_unlock(&q->debugfs_mutex);
1858out:
1859 return ret ? ret : count;
1860}
1861#endif /* CONFIG_BLK_DEV_IO_TRACE */
1862
1863#ifdef CONFIG_EVENT_TRACING
1864
1865/**
1866 * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string.
1867 * @rwbs: buffer to be filled
1868 * @opf: request operation type (REQ_OP_XXX) and flags for the tracepoint
1869 *
1870 * Description:
1871 * Maps each request operation and flag to a single character and fills the
1872 * buffer provided by the caller with resulting string.
1873 *
1874 **/
1875void blk_fill_rwbs(char *rwbs, blk_opf_t opf)
1876{
1877 int i = 0;
1878
1879 if (opf & REQ_PREFLUSH)
1880 rwbs[i++] = 'F';
1881
1882 switch (opf & REQ_OP_MASK) {
1883 case REQ_OP_WRITE:
1884 rwbs[i++] = 'W';
1885 break;
1886 case REQ_OP_DISCARD:
1887 rwbs[i++] = 'D';
1888 break;
1889 case REQ_OP_SECURE_ERASE:
1890 rwbs[i++] = 'D';
1891 rwbs[i++] = 'E';
1892 break;
1893 case REQ_OP_FLUSH:
1894 rwbs[i++] = 'F';
1895 break;
1896 case REQ_OP_READ:
1897 rwbs[i++] = 'R';
1898 break;
1899 default:
1900 rwbs[i++] = 'N';
1901 }
1902
1903 if (opf & REQ_FUA)
1904 rwbs[i++] = 'F';
1905 if (opf & REQ_RAHEAD)
1906 rwbs[i++] = 'A';
1907 if (opf & REQ_SYNC)
1908 rwbs[i++] = 'S';
1909 if (opf & REQ_META)
1910 rwbs[i++] = 'M';
1911
1912 rwbs[i] = '\0';
1913}
1914EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1915
1916#endif /* CONFIG_EVENT_TRACING */
1917