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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_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 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 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 __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
149 const char *fmt, ...)
150{
151 int n;
152 va_list args;
153 unsigned long flags;
154 char *buf;
155
156 if (unlikely(bt->trace_state != Blktrace_running &&
157 !blk_tracer_enabled))
158 return;
159
160 /*
161 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
162 * message to the trace.
163 */
164 if (!(bt->act_mask & BLK_TC_NOTIFY))
165 return;
166
167 local_irq_save(flags);
168 buf = this_cpu_ptr(bt->msg_data);
169 va_start(args, fmt);
170 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
171 va_end(args);
172
173 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
174 blkcg = NULL;
175#ifdef CONFIG_BLK_CGROUP
176 trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n,
177 blkcg ? cgroup_id(blkcg->css.cgroup) : 1);
178#else
179 trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n, 0);
180#endif
181 local_irq_restore(flags);
182}
183EXPORT_SYMBOL_GPL(__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) ((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 int op, int op_flags, u32 what, int error, int pdu_len,
217 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
231 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
232 return;
233
234 what |= ddir_act[op_is_write(op) ? WRITE : READ];
235 what |= MASK_TC_BIT(op_flags, SYNC);
236 what |= MASK_TC_BIT(op_flags, RAHEAD);
237 what |= MASK_TC_BIT(op_flags, META);
238 what |= MASK_TC_BIT(op_flags, PREFLUSH);
239 what |= MASK_TC_BIT(op_flags, FUA);
240 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
241 what |= BLK_TC_ACT(BLK_TC_DISCARD);
242 if (op == REQ_OP_FLUSH)
243 what |= BLK_TC_ACT(BLK_TC_FLUSH);
244 if (cgid)
245 what |= __BLK_TA_CGROUP;
246
247 pid = tsk->pid;
248 if (act_log_check(bt, what, sector, pid))
249 return;
250 cpu = raw_smp_processor_id();
251
252 if (blk_tracer) {
253 tracing_record_cmdline(current);
254
255 buffer = blk_tr->array_buffer.buffer;
256 trace_ctx = tracing_gen_ctx_flags(0);
257 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
258 sizeof(*t) + pdu_len + cgid_len,
259 trace_ctx);
260 if (!event)
261 return;
262 t = ring_buffer_event_data(event);
263 goto record_it;
264 }
265
266 if (unlikely(tsk->btrace_seq != blktrace_seq))
267 trace_note_tsk(tsk);
268
269 /*
270 * A word about the locking here - we disable interrupts to reserve
271 * some space in the relay per-cpu buffer, to prevent an irq
272 * from coming in and stepping on our toes.
273 */
274 local_irq_save(flags);
275 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
276 if (t) {
277 sequence = per_cpu_ptr(bt->sequence, cpu);
278
279 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
280 t->sequence = ++(*sequence);
281 t->time = ktime_to_ns(ktime_get());
282record_it:
283 /*
284 * These two are not needed in ftrace as they are in the
285 * generic trace_entry, filled by tracing_generic_entry_update,
286 * but for the trace_event->bin() synthesizer benefit we do it
287 * here too.
288 */
289 t->cpu = cpu;
290 t->pid = pid;
291
292 t->sector = sector;
293 t->bytes = bytes;
294 t->action = what;
295 t->device = bt->dev;
296 t->error = error;
297 t->pdu_len = pdu_len + cgid_len;
298
299 if (cgid_len)
300 memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
301 if (pdu_len)
302 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
303
304 if (blk_tracer) {
305 trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
306 return;
307 }
308 }
309
310 local_irq_restore(flags);
311}
312
313static void blk_trace_free(struct blk_trace *bt)
314{
315 relay_close(bt->rchan);
316 debugfs_remove(bt->dir);
317 free_percpu(bt->sequence);
318 free_percpu(bt->msg_data);
319 kfree(bt);
320}
321
322static void get_probe_ref(void)
323{
324 mutex_lock(&blk_probe_mutex);
325 if (++blk_probes_ref == 1)
326 blk_register_tracepoints();
327 mutex_unlock(&blk_probe_mutex);
328}
329
330static void put_probe_ref(void)
331{
332 mutex_lock(&blk_probe_mutex);
333 if (!--blk_probes_ref)
334 blk_unregister_tracepoints();
335 mutex_unlock(&blk_probe_mutex);
336}
337
338static void blk_trace_cleanup(struct blk_trace *bt)
339{
340 synchronize_rcu();
341 blk_trace_free(bt);
342 put_probe_ref();
343}
344
345static int __blk_trace_remove(struct request_queue *q)
346{
347 struct blk_trace *bt;
348
349 bt = rcu_replace_pointer(q->blk_trace, NULL,
350 lockdep_is_held(&q->debugfs_mutex));
351 if (!bt)
352 return -EINVAL;
353
354 if (bt->trace_state != Blktrace_running)
355 blk_trace_cleanup(bt);
356
357 return 0;
358}
359
360int blk_trace_remove(struct request_queue *q)
361{
362 int ret;
363
364 mutex_lock(&q->debugfs_mutex);
365 ret = __blk_trace_remove(q);
366 mutex_unlock(&q->debugfs_mutex);
367
368 return ret;
369}
370EXPORT_SYMBOL_GPL(blk_trace_remove);
371
372static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
373 size_t count, loff_t *ppos)
374{
375 struct blk_trace *bt = filp->private_data;
376 char buf[16];
377
378 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
379
380 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
381}
382
383static const struct file_operations blk_dropped_fops = {
384 .owner = THIS_MODULE,
385 .open = simple_open,
386 .read = blk_dropped_read,
387 .llseek = default_llseek,
388};
389
390static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
391 size_t count, loff_t *ppos)
392{
393 char *msg;
394 struct blk_trace *bt;
395
396 if (count >= BLK_TN_MAX_MSG)
397 return -EINVAL;
398
399 msg = memdup_user_nul(buffer, count);
400 if (IS_ERR(msg))
401 return PTR_ERR(msg);
402
403 bt = filp->private_data;
404 __trace_note_message(bt, NULL, "%s", msg);
405 kfree(msg);
406
407 return count;
408}
409
410static const struct file_operations blk_msg_fops = {
411 .owner = THIS_MODULE,
412 .open = simple_open,
413 .write = blk_msg_write,
414 .llseek = noop_llseek,
415};
416
417/*
418 * Keep track of how many times we encountered a full subbuffer, to aid
419 * the user space app in telling how many lost events there were.
420 */
421static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
422 void *prev_subbuf, size_t prev_padding)
423{
424 struct blk_trace *bt;
425
426 if (!relay_buf_full(buf))
427 return 1;
428
429 bt = buf->chan->private_data;
430 atomic_inc(&bt->dropped);
431 return 0;
432}
433
434static int blk_remove_buf_file_callback(struct dentry *dentry)
435{
436 debugfs_remove(dentry);
437
438 return 0;
439}
440
441static struct dentry *blk_create_buf_file_callback(const char *filename,
442 struct dentry *parent,
443 umode_t mode,
444 struct rchan_buf *buf,
445 int *is_global)
446{
447 return debugfs_create_file(filename, mode, parent, buf,
448 &relay_file_operations);
449}
450
451static const struct rchan_callbacks blk_relay_callbacks = {
452 .subbuf_start = blk_subbuf_start_callback,
453 .create_buf_file = blk_create_buf_file_callback,
454 .remove_buf_file = blk_remove_buf_file_callback,
455};
456
457static void blk_trace_setup_lba(struct blk_trace *bt,
458 struct block_device *bdev)
459{
460 if (bdev) {
461 bt->start_lba = bdev->bd_start_sect;
462 bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev);
463 } else {
464 bt->start_lba = 0;
465 bt->end_lba = -1ULL;
466 }
467}
468
469/*
470 * Setup everything required to start tracing
471 */
472static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
473 struct block_device *bdev,
474 struct blk_user_trace_setup *buts)
475{
476 struct blk_trace *bt = NULL;
477 struct dentry *dir = NULL;
478 int ret;
479
480 lockdep_assert_held(&q->debugfs_mutex);
481
482 if (!buts->buf_size || !buts->buf_nr)
483 return -EINVAL;
484
485 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
486 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
487
488 /*
489 * some device names have larger paths - convert the slashes
490 * to underscores for this to work as expected
491 */
492 strreplace(buts->name, '/', '_');
493
494 /*
495 * bdev can be NULL, as with scsi-generic, this is a helpful as
496 * we can be.
497 */
498 if (rcu_dereference_protected(q->blk_trace,
499 lockdep_is_held(&q->debugfs_mutex))) {
500 pr_warn("Concurrent blktraces are not allowed on %s\n",
501 buts->name);
502 return -EBUSY;
503 }
504
505 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
506 if (!bt)
507 return -ENOMEM;
508
509 ret = -ENOMEM;
510 bt->sequence = alloc_percpu(unsigned long);
511 if (!bt->sequence)
512 goto err;
513
514 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
515 if (!bt->msg_data)
516 goto err;
517
518 /*
519 * When tracing the whole disk reuse the existing debugfs directory
520 * created by the block layer on init. For partitions block devices,
521 * and scsi-generic block devices we create a temporary new debugfs
522 * directory that will be removed once the trace ends.
523 */
524 if (bdev && !bdev_is_partition(bdev))
525 dir = q->debugfs_dir;
526 else
527 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
528
529 /*
530 * As blktrace relies on debugfs for its interface the debugfs directory
531 * is required, contrary to the usual mantra of not checking for debugfs
532 * files or directories.
533 */
534 if (IS_ERR_OR_NULL(dir)) {
535 pr_warn("debugfs_dir not present for %s so skipping\n",
536 buts->name);
537 ret = -ENOENT;
538 goto err;
539 }
540
541 bt->dev = dev;
542 atomic_set(&bt->dropped, 0);
543 INIT_LIST_HEAD(&bt->running_list);
544
545 ret = -EIO;
546 debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
547 debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
548
549 bt->rchan = relay_open("trace", dir, buts->buf_size,
550 buts->buf_nr, &blk_relay_callbacks, bt);
551 if (!bt->rchan)
552 goto err;
553
554 bt->act_mask = buts->act_mask;
555 if (!bt->act_mask)
556 bt->act_mask = (u16) -1;
557
558 blk_trace_setup_lba(bt, bdev);
559
560 /* overwrite with user settings */
561 if (buts->start_lba)
562 bt->start_lba = buts->start_lba;
563 if (buts->end_lba)
564 bt->end_lba = buts->end_lba;
565
566 bt->pid = buts->pid;
567 bt->trace_state = Blktrace_setup;
568
569 rcu_assign_pointer(q->blk_trace, bt);
570 get_probe_ref();
571
572 ret = 0;
573err:
574 if (ret)
575 blk_trace_free(bt);
576 return ret;
577}
578
579static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
580 struct block_device *bdev, char __user *arg)
581{
582 struct blk_user_trace_setup buts;
583 int ret;
584
585 ret = copy_from_user(&buts, arg, sizeof(buts));
586 if (ret)
587 return -EFAULT;
588
589 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
590 if (ret)
591 return ret;
592
593 if (copy_to_user(arg, &buts, sizeof(buts))) {
594 __blk_trace_remove(q);
595 return -EFAULT;
596 }
597 return 0;
598}
599
600int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
601 struct block_device *bdev,
602 char __user *arg)
603{
604 int ret;
605
606 mutex_lock(&q->debugfs_mutex);
607 ret = __blk_trace_setup(q, name, dev, bdev, arg);
608 mutex_unlock(&q->debugfs_mutex);
609
610 return ret;
611}
612EXPORT_SYMBOL_GPL(blk_trace_setup);
613
614#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
615static int compat_blk_trace_setup(struct request_queue *q, char *name,
616 dev_t dev, struct block_device *bdev,
617 char __user *arg)
618{
619 struct blk_user_trace_setup buts;
620 struct compat_blk_user_trace_setup cbuts;
621 int ret;
622
623 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
624 return -EFAULT;
625
626 buts = (struct blk_user_trace_setup) {
627 .act_mask = cbuts.act_mask,
628 .buf_size = cbuts.buf_size,
629 .buf_nr = cbuts.buf_nr,
630 .start_lba = cbuts.start_lba,
631 .end_lba = cbuts.end_lba,
632 .pid = cbuts.pid,
633 };
634
635 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
636 if (ret)
637 return ret;
638
639 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
640 __blk_trace_remove(q);
641 return -EFAULT;
642 }
643
644 return 0;
645}
646#endif
647
648static int __blk_trace_startstop(struct request_queue *q, int start)
649{
650 int ret;
651 struct blk_trace *bt;
652
653 bt = rcu_dereference_protected(q->blk_trace,
654 lockdep_is_held(&q->debugfs_mutex));
655 if (bt == NULL)
656 return -EINVAL;
657
658 /*
659 * For starting a trace, we can transition from a setup or stopped
660 * trace. For stopping a trace, the state must be running
661 */
662 ret = -EINVAL;
663 if (start) {
664 if (bt->trace_state == Blktrace_setup ||
665 bt->trace_state == Blktrace_stopped) {
666 blktrace_seq++;
667 smp_mb();
668 bt->trace_state = Blktrace_running;
669 spin_lock_irq(&running_trace_lock);
670 list_add(&bt->running_list, &running_trace_list);
671 spin_unlock_irq(&running_trace_lock);
672
673 trace_note_time(bt);
674 ret = 0;
675 }
676 } else {
677 if (bt->trace_state == Blktrace_running) {
678 bt->trace_state = Blktrace_stopped;
679 spin_lock_irq(&running_trace_lock);
680 list_del_init(&bt->running_list);
681 spin_unlock_irq(&running_trace_lock);
682 relay_flush(bt->rchan);
683 ret = 0;
684 }
685 }
686
687 return ret;
688}
689
690int blk_trace_startstop(struct request_queue *q, int start)
691{
692 int ret;
693
694 mutex_lock(&q->debugfs_mutex);
695 ret = __blk_trace_startstop(q, start);
696 mutex_unlock(&q->debugfs_mutex);
697
698 return ret;
699}
700EXPORT_SYMBOL_GPL(blk_trace_startstop);
701
702/*
703 * When reading or writing the blktrace sysfs files, the references to the
704 * opened sysfs or device files should prevent the underlying block device
705 * from being removed. So no further delete protection is really needed.
706 */
707
708/**
709 * blk_trace_ioctl: - handle the ioctls associated with tracing
710 * @bdev: the block device
711 * @cmd: the ioctl cmd
712 * @arg: the argument data, if any
713 *
714 **/
715int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
716{
717 struct request_queue *q;
718 int ret, start = 0;
719 char b[BDEVNAME_SIZE];
720
721 q = bdev_get_queue(bdev);
722 if (!q)
723 return -ENXIO;
724
725 mutex_lock(&q->debugfs_mutex);
726
727 switch (cmd) {
728 case BLKTRACESETUP:
729 bdevname(bdev, b);
730 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
731 break;
732#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
733 case BLKTRACESETUP32:
734 bdevname(bdev, b);
735 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
736 break;
737#endif
738 case BLKTRACESTART:
739 start = 1;
740 fallthrough;
741 case BLKTRACESTOP:
742 ret = __blk_trace_startstop(q, start);
743 break;
744 case BLKTRACETEARDOWN:
745 ret = __blk_trace_remove(q);
746 break;
747 default:
748 ret = -ENOTTY;
749 break;
750 }
751
752 mutex_unlock(&q->debugfs_mutex);
753 return ret;
754}
755
756/**
757 * blk_trace_shutdown: - stop and cleanup trace structures
758 * @q: the request queue associated with the device
759 *
760 **/
761void blk_trace_shutdown(struct request_queue *q)
762{
763 mutex_lock(&q->debugfs_mutex);
764 if (rcu_dereference_protected(q->blk_trace,
765 lockdep_is_held(&q->debugfs_mutex))) {
766 __blk_trace_startstop(q, 0);
767 __blk_trace_remove(q);
768 }
769
770 mutex_unlock(&q->debugfs_mutex);
771}
772
773#ifdef CONFIG_BLK_CGROUP
774static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
775{
776 struct blk_trace *bt;
777
778 /* We don't use the 'bt' value here except as an optimization... */
779 bt = rcu_dereference_protected(q->blk_trace, 1);
780 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
781 return 0;
782
783 if (!bio->bi_blkg)
784 return 0;
785 return cgroup_id(bio_blkcg(bio)->css.cgroup);
786}
787#else
788static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
789{
790 return 0;
791}
792#endif
793
794static u64
795blk_trace_request_get_cgid(struct request *rq)
796{
797 if (!rq->bio)
798 return 0;
799 /* Use the first bio */
800 return blk_trace_bio_get_cgid(rq->q, rq->bio);
801}
802
803/*
804 * blktrace probes
805 */
806
807/**
808 * blk_add_trace_rq - Add a trace for a request oriented action
809 * @rq: the source request
810 * @error: return status to log
811 * @nr_bytes: number of completed bytes
812 * @what: the action
813 * @cgid: the cgroup info
814 *
815 * Description:
816 * Records an action against a request. Will log the bio offset + size.
817 *
818 **/
819static void blk_add_trace_rq(struct request *rq, int error,
820 unsigned int nr_bytes, u32 what, u64 cgid)
821{
822 struct blk_trace *bt;
823
824 rcu_read_lock();
825 bt = rcu_dereference(rq->q->blk_trace);
826 if (likely(!bt)) {
827 rcu_read_unlock();
828 return;
829 }
830
831 if (blk_rq_is_passthrough(rq))
832 what |= BLK_TC_ACT(BLK_TC_PC);
833 else
834 what |= BLK_TC_ACT(BLK_TC_FS);
835
836 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
837 rq->cmd_flags, what, error, 0, NULL, cgid);
838 rcu_read_unlock();
839}
840
841static void blk_add_trace_rq_insert(void *ignore, struct request *rq)
842{
843 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
844 blk_trace_request_get_cgid(rq));
845}
846
847static void blk_add_trace_rq_issue(void *ignore, struct request *rq)
848{
849 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
850 blk_trace_request_get_cgid(rq));
851}
852
853static void blk_add_trace_rq_merge(void *ignore, struct request *rq)
854{
855 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
856 blk_trace_request_get_cgid(rq));
857}
858
859static void blk_add_trace_rq_requeue(void *ignore, struct request *rq)
860{
861 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
862 blk_trace_request_get_cgid(rq));
863}
864
865static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
866 int error, unsigned int nr_bytes)
867{
868 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
869 blk_trace_request_get_cgid(rq));
870}
871
872/**
873 * blk_add_trace_bio - Add a trace for a bio oriented action
874 * @q: queue the io is for
875 * @bio: the source bio
876 * @what: the action
877 * @error: error, if any
878 *
879 * Description:
880 * Records an action against a bio. Will log the bio offset + size.
881 *
882 **/
883static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
884 u32 what, int error)
885{
886 struct blk_trace *bt;
887
888 rcu_read_lock();
889 bt = rcu_dereference(q->blk_trace);
890 if (likely(!bt)) {
891 rcu_read_unlock();
892 return;
893 }
894
895 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
896 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
897 blk_trace_bio_get_cgid(q, bio));
898 rcu_read_unlock();
899}
900
901static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio)
902{
903 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0);
904}
905
906static void blk_add_trace_bio_complete(void *ignore,
907 struct request_queue *q, struct bio *bio)
908{
909 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
910 blk_status_to_errno(bio->bi_status));
911}
912
913static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio)
914{
915 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE,
916 0);
917}
918
919static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio)
920{
921 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE,
922 0);
923}
924
925static void blk_add_trace_bio_queue(void *ignore, struct bio *bio)
926{
927 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0);
928}
929
930static void blk_add_trace_getrq(void *ignore, struct bio *bio)
931{
932 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0);
933}
934
935static void blk_add_trace_plug(void *ignore, struct request_queue *q)
936{
937 struct blk_trace *bt;
938
939 rcu_read_lock();
940 bt = rcu_dereference(q->blk_trace);
941 if (bt)
942 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
943 rcu_read_unlock();
944}
945
946static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
947 unsigned int depth, bool explicit)
948{
949 struct blk_trace *bt;
950
951 rcu_read_lock();
952 bt = rcu_dereference(q->blk_trace);
953 if (bt) {
954 __be64 rpdu = cpu_to_be64(depth);
955 u32 what;
956
957 if (explicit)
958 what = BLK_TA_UNPLUG_IO;
959 else
960 what = BLK_TA_UNPLUG_TIMER;
961
962 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
963 }
964 rcu_read_unlock();
965}
966
967static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
968{
969 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
970 struct blk_trace *bt;
971
972 rcu_read_lock();
973 bt = rcu_dereference(q->blk_trace);
974 if (bt) {
975 __be64 rpdu = cpu_to_be64(pdu);
976
977 __blk_add_trace(bt, bio->bi_iter.bi_sector,
978 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
979 BLK_TA_SPLIT,
980 blk_status_to_errno(bio->bi_status),
981 sizeof(rpdu), &rpdu,
982 blk_trace_bio_get_cgid(q, bio));
983 }
984 rcu_read_unlock();
985}
986
987/**
988 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
989 * @ignore: trace callback data parameter (not used)
990 * @bio: the source bio
991 * @dev: source device
992 * @from: source sector
993 *
994 * Called after a bio is remapped to a different device and/or sector.
995 **/
996static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev,
997 sector_t from)
998{
999 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
1000 struct blk_trace *bt;
1001 struct blk_io_trace_remap r;
1002
1003 rcu_read_lock();
1004 bt = rcu_dereference(q->blk_trace);
1005 if (likely(!bt)) {
1006 rcu_read_unlock();
1007 return;
1008 }
1009
1010 r.device_from = cpu_to_be32(dev);
1011 r.device_to = cpu_to_be32(bio_dev(bio));
1012 r.sector_from = cpu_to_be64(from);
1013
1014 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1015 bio_op(bio), bio->bi_opf, BLK_TA_REMAP,
1016 blk_status_to_errno(bio->bi_status),
1017 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1018 rcu_read_unlock();
1019}
1020
1021/**
1022 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1023 * @ignore: trace callback data parameter (not used)
1024 * @rq: the source request
1025 * @dev: target device
1026 * @from: source sector
1027 *
1028 * Description:
1029 * Device mapper remaps request to other devices.
1030 * Add a trace for that action.
1031 *
1032 **/
1033static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev,
1034 sector_t from)
1035{
1036 struct blk_trace *bt;
1037 struct blk_io_trace_remap r;
1038
1039 rcu_read_lock();
1040 bt = rcu_dereference(rq->q->blk_trace);
1041 if (likely(!bt)) {
1042 rcu_read_unlock();
1043 return;
1044 }
1045
1046 r.device_from = cpu_to_be32(dev);
1047 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1048 r.sector_from = cpu_to_be64(from);
1049
1050 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1051 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1052 sizeof(r), &r, blk_trace_request_get_cgid(rq));
1053 rcu_read_unlock();
1054}
1055
1056/**
1057 * blk_add_driver_data - Add binary message with driver-specific data
1058 * @rq: io request
1059 * @data: driver-specific data
1060 * @len: length of driver-specific data
1061 *
1062 * Description:
1063 * Some drivers might want to write driver-specific data per request.
1064 *
1065 **/
1066void blk_add_driver_data(struct request *rq, void *data, size_t len)
1067{
1068 struct blk_trace *bt;
1069
1070 rcu_read_lock();
1071 bt = rcu_dereference(rq->q->blk_trace);
1072 if (likely(!bt)) {
1073 rcu_read_unlock();
1074 return;
1075 }
1076
1077 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1078 BLK_TA_DRV_DATA, 0, len, data,
1079 blk_trace_request_get_cgid(rq));
1080 rcu_read_unlock();
1081}
1082EXPORT_SYMBOL_GPL(blk_add_driver_data);
1083
1084static void blk_register_tracepoints(void)
1085{
1086 int ret;
1087
1088 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1089 WARN_ON(ret);
1090 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1091 WARN_ON(ret);
1092 ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1093 WARN_ON(ret);
1094 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1095 WARN_ON(ret);
1096 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1097 WARN_ON(ret);
1098 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1099 WARN_ON(ret);
1100 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1101 WARN_ON(ret);
1102 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1103 WARN_ON(ret);
1104 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1105 WARN_ON(ret);
1106 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1107 WARN_ON(ret);
1108 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1109 WARN_ON(ret);
1110 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1111 WARN_ON(ret);
1112 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1113 WARN_ON(ret);
1114 ret = register_trace_block_split(blk_add_trace_split, NULL);
1115 WARN_ON(ret);
1116 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1117 WARN_ON(ret);
1118 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1119 WARN_ON(ret);
1120}
1121
1122static void blk_unregister_tracepoints(void)
1123{
1124 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1125 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1126 unregister_trace_block_split(blk_add_trace_split, NULL);
1127 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1128 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1129 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1130 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1131 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1132 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1133 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1134 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1135 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1136 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1137 unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1138 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1139 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1140
1141 tracepoint_synchronize_unregister();
1142}
1143
1144/*
1145 * struct blk_io_tracer formatting routines
1146 */
1147
1148static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1149{
1150 int i = 0;
1151 int tc = t->action >> BLK_TC_SHIFT;
1152
1153 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1154 rwbs[i++] = 'N';
1155 goto out;
1156 }
1157
1158 if (tc & BLK_TC_FLUSH)
1159 rwbs[i++] = 'F';
1160
1161 if (tc & BLK_TC_DISCARD)
1162 rwbs[i++] = 'D';
1163 else if (tc & BLK_TC_WRITE)
1164 rwbs[i++] = 'W';
1165 else if (t->bytes)
1166 rwbs[i++] = 'R';
1167 else
1168 rwbs[i++] = 'N';
1169
1170 if (tc & BLK_TC_FUA)
1171 rwbs[i++] = 'F';
1172 if (tc & BLK_TC_AHEAD)
1173 rwbs[i++] = 'A';
1174 if (tc & BLK_TC_SYNC)
1175 rwbs[i++] = 'S';
1176 if (tc & BLK_TC_META)
1177 rwbs[i++] = 'M';
1178out:
1179 rwbs[i] = '\0';
1180}
1181
1182static inline
1183const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1184{
1185 return (const struct blk_io_trace *)ent;
1186}
1187
1188static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1189{
1190 return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
1191}
1192
1193static inline u64 t_cgid(const struct trace_entry *ent)
1194{
1195 return *(u64 *)(te_blk_io_trace(ent) + 1);
1196}
1197
1198static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1199{
1200 return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
1201}
1202
1203static inline u32 t_action(const struct trace_entry *ent)
1204{
1205 return te_blk_io_trace(ent)->action;
1206}
1207
1208static inline u32 t_bytes(const struct trace_entry *ent)
1209{
1210 return te_blk_io_trace(ent)->bytes;
1211}
1212
1213static inline u32 t_sec(const struct trace_entry *ent)
1214{
1215 return te_blk_io_trace(ent)->bytes >> 9;
1216}
1217
1218static inline unsigned long long t_sector(const struct trace_entry *ent)
1219{
1220 return te_blk_io_trace(ent)->sector;
1221}
1222
1223static inline __u16 t_error(const struct trace_entry *ent)
1224{
1225 return te_blk_io_trace(ent)->error;
1226}
1227
1228static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1229{
1230 const __be64 *val = pdu_start(ent, has_cg);
1231 return be64_to_cpu(*val);
1232}
1233
1234typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1235 bool has_cg);
1236
1237static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1238 bool has_cg)
1239{
1240 char rwbs[RWBS_LEN];
1241 unsigned long long ts = iter->ts;
1242 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1243 unsigned secs = (unsigned long)ts;
1244 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1245
1246 fill_rwbs(rwbs, t);
1247
1248 trace_seq_printf(&iter->seq,
1249 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1250 MAJOR(t->device), MINOR(t->device), iter->cpu,
1251 secs, nsec_rem, iter->ent->pid, act, rwbs);
1252}
1253
1254static void blk_log_action(struct trace_iterator *iter, const char *act,
1255 bool has_cg)
1256{
1257 char rwbs[RWBS_LEN];
1258 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1259
1260 fill_rwbs(rwbs, t);
1261 if (has_cg) {
1262 u64 id = t_cgid(iter->ent);
1263
1264 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1265 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1266
1267 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1268 sizeof(blkcg_name_buf));
1269 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1270 MAJOR(t->device), MINOR(t->device),
1271 blkcg_name_buf, act, rwbs);
1272 } else {
1273 /*
1274 * The cgid portion used to be "INO,GEN". Userland
1275 * builds a FILEID_INO32_GEN fid out of them and
1276 * opens the cgroup using open_by_handle_at(2).
1277 * While 32bit ino setups are still the same, 64bit
1278 * ones now use the 64bit ino as the whole ID and
1279 * no longer use generation.
1280 *
1281 * Regardless of the content, always output
1282 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
1283 * be mapped back to @id on both 64 and 32bit ino
1284 * setups. See __kernfs_fh_to_dentry().
1285 */
1286 trace_seq_printf(&iter->seq,
1287 "%3d,%-3d %llx,%-llx %2s %3s ",
1288 MAJOR(t->device), MINOR(t->device),
1289 id & U32_MAX, id >> 32, act, rwbs);
1290 }
1291 } else
1292 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1293 MAJOR(t->device), MINOR(t->device), act, rwbs);
1294}
1295
1296static void blk_log_dump_pdu(struct trace_seq *s,
1297 const struct trace_entry *ent, bool has_cg)
1298{
1299 const unsigned char *pdu_buf;
1300 int pdu_len;
1301 int i, end;
1302
1303 pdu_buf = pdu_start(ent, has_cg);
1304 pdu_len = pdu_real_len(ent, has_cg);
1305
1306 if (!pdu_len)
1307 return;
1308
1309 /* find the last zero that needs to be printed */
1310 for (end = pdu_len - 1; end >= 0; end--)
1311 if (pdu_buf[end])
1312 break;
1313 end++;
1314
1315 trace_seq_putc(s, '(');
1316
1317 for (i = 0; i < pdu_len; i++) {
1318
1319 trace_seq_printf(s, "%s%02x",
1320 i == 0 ? "" : " ", pdu_buf[i]);
1321
1322 /*
1323 * stop when the rest is just zeros and indicate so
1324 * with a ".." appended
1325 */
1326 if (i == end && end != pdu_len - 1) {
1327 trace_seq_puts(s, " ..) ");
1328 return;
1329 }
1330 }
1331
1332 trace_seq_puts(s, ") ");
1333}
1334
1335static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1336{
1337 char cmd[TASK_COMM_LEN];
1338
1339 trace_find_cmdline(ent->pid, cmd);
1340
1341 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1342 trace_seq_printf(s, "%u ", t_bytes(ent));
1343 blk_log_dump_pdu(s, ent, has_cg);
1344 trace_seq_printf(s, "[%s]\n", cmd);
1345 } else {
1346 if (t_sec(ent))
1347 trace_seq_printf(s, "%llu + %u [%s]\n",
1348 t_sector(ent), t_sec(ent), cmd);
1349 else
1350 trace_seq_printf(s, "[%s]\n", cmd);
1351 }
1352}
1353
1354static void blk_log_with_error(struct trace_seq *s,
1355 const struct trace_entry *ent, bool has_cg)
1356{
1357 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1358 blk_log_dump_pdu(s, ent, has_cg);
1359 trace_seq_printf(s, "[%d]\n", t_error(ent));
1360 } else {
1361 if (t_sec(ent))
1362 trace_seq_printf(s, "%llu + %u [%d]\n",
1363 t_sector(ent),
1364 t_sec(ent), t_error(ent));
1365 else
1366 trace_seq_printf(s, "%llu [%d]\n",
1367 t_sector(ent), t_error(ent));
1368 }
1369}
1370
1371static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1372{
1373 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1374
1375 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1376 t_sector(ent), t_sec(ent),
1377 MAJOR(be32_to_cpu(__r->device_from)),
1378 MINOR(be32_to_cpu(__r->device_from)),
1379 be64_to_cpu(__r->sector_from));
1380}
1381
1382static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1383{
1384 char cmd[TASK_COMM_LEN];
1385
1386 trace_find_cmdline(ent->pid, cmd);
1387
1388 trace_seq_printf(s, "[%s]\n", cmd);
1389}
1390
1391static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1392{
1393 char cmd[TASK_COMM_LEN];
1394
1395 trace_find_cmdline(ent->pid, cmd);
1396
1397 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1398}
1399
1400static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1401{
1402 char cmd[TASK_COMM_LEN];
1403
1404 trace_find_cmdline(ent->pid, cmd);
1405
1406 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1407 get_pdu_int(ent, has_cg), cmd);
1408}
1409
1410static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1411 bool has_cg)
1412{
1413
1414 trace_seq_putmem(s, pdu_start(ent, has_cg),
1415 pdu_real_len(ent, has_cg));
1416 trace_seq_putc(s, '\n');
1417}
1418
1419/*
1420 * struct tracer operations
1421 */
1422
1423static void blk_tracer_print_header(struct seq_file *m)
1424{
1425 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1426 return;
1427 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1428 "# | | | | | |\n");
1429}
1430
1431static void blk_tracer_start(struct trace_array *tr)
1432{
1433 blk_tracer_enabled = true;
1434}
1435
1436static int blk_tracer_init(struct trace_array *tr)
1437{
1438 blk_tr = tr;
1439 blk_tracer_start(tr);
1440 return 0;
1441}
1442
1443static void blk_tracer_stop(struct trace_array *tr)
1444{
1445 blk_tracer_enabled = false;
1446}
1447
1448static void blk_tracer_reset(struct trace_array *tr)
1449{
1450 blk_tracer_stop(tr);
1451}
1452
1453static const struct {
1454 const char *act[2];
1455 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1456 bool has_cg);
1457} what2act[] = {
1458 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1459 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1460 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1461 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1462 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1463 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1464 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1465 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1466 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1467 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1468 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1469 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1470 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1471 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1472 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1473};
1474
1475static enum print_line_t print_one_line(struct trace_iterator *iter,
1476 bool classic)
1477{
1478 struct trace_array *tr = iter->tr;
1479 struct trace_seq *s = &iter->seq;
1480 const struct blk_io_trace *t;
1481 u16 what;
1482 bool long_act;
1483 blk_log_action_t *log_action;
1484 bool has_cg;
1485
1486 t = te_blk_io_trace(iter->ent);
1487 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1488 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1489 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1490 has_cg = t->action & __BLK_TA_CGROUP;
1491
1492 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1493 log_action(iter, long_act ? "message" : "m", has_cg);
1494 blk_log_msg(s, iter->ent, has_cg);
1495 return trace_handle_return(s);
1496 }
1497
1498 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1499 trace_seq_printf(s, "Unknown action %x\n", what);
1500 else {
1501 log_action(iter, what2act[what].act[long_act], has_cg);
1502 what2act[what].print(s, iter->ent, has_cg);
1503 }
1504
1505 return trace_handle_return(s);
1506}
1507
1508static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1509 int flags, struct trace_event *event)
1510{
1511 return print_one_line(iter, false);
1512}
1513
1514static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1515{
1516 struct trace_seq *s = &iter->seq;
1517 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1518 const int offset = offsetof(struct blk_io_trace, sector);
1519 struct blk_io_trace old = {
1520 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1521 .time = iter->ts,
1522 };
1523
1524 trace_seq_putmem(s, &old, offset);
1525 trace_seq_putmem(s, &t->sector,
1526 sizeof(old) - offset + t->pdu_len);
1527}
1528
1529static enum print_line_t
1530blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1531 struct trace_event *event)
1532{
1533 blk_trace_synthesize_old_trace(iter);
1534
1535 return trace_handle_return(&iter->seq);
1536}
1537
1538static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1539{
1540 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1541 return TRACE_TYPE_UNHANDLED;
1542
1543 return print_one_line(iter, true);
1544}
1545
1546static int
1547blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1548{
1549 /* don't output context-info for blk_classic output */
1550 if (bit == TRACE_BLK_OPT_CLASSIC) {
1551 if (set)
1552 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1553 else
1554 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1555 }
1556 return 0;
1557}
1558
1559static struct tracer blk_tracer __read_mostly = {
1560 .name = "blk",
1561 .init = blk_tracer_init,
1562 .reset = blk_tracer_reset,
1563 .start = blk_tracer_start,
1564 .stop = blk_tracer_stop,
1565 .print_header = blk_tracer_print_header,
1566 .print_line = blk_tracer_print_line,
1567 .flags = &blk_tracer_flags,
1568 .set_flag = blk_tracer_set_flag,
1569};
1570
1571static struct trace_event_functions trace_blk_event_funcs = {
1572 .trace = blk_trace_event_print,
1573 .binary = blk_trace_event_print_binary,
1574};
1575
1576static struct trace_event trace_blk_event = {
1577 .type = TRACE_BLK,
1578 .funcs = &trace_blk_event_funcs,
1579};
1580
1581static int __init init_blk_tracer(void)
1582{
1583 if (!register_trace_event(&trace_blk_event)) {
1584 pr_warn("Warning: could not register block events\n");
1585 return 1;
1586 }
1587
1588 if (register_tracer(&blk_tracer) != 0) {
1589 pr_warn("Warning: could not register the block tracer\n");
1590 unregister_trace_event(&trace_blk_event);
1591 return 1;
1592 }
1593
1594 return 0;
1595}
1596
1597device_initcall(init_blk_tracer);
1598
1599static int blk_trace_remove_queue(struct request_queue *q)
1600{
1601 struct blk_trace *bt;
1602
1603 bt = rcu_replace_pointer(q->blk_trace, NULL,
1604 lockdep_is_held(&q->debugfs_mutex));
1605 if (bt == NULL)
1606 return -EINVAL;
1607
1608 if (bt->trace_state == Blktrace_running) {
1609 bt->trace_state = Blktrace_stopped;
1610 spin_lock_irq(&running_trace_lock);
1611 list_del_init(&bt->running_list);
1612 spin_unlock_irq(&running_trace_lock);
1613 relay_flush(bt->rchan);
1614 }
1615
1616 put_probe_ref();
1617 synchronize_rcu();
1618 blk_trace_free(bt);
1619 return 0;
1620}
1621
1622/*
1623 * Setup everything required to start tracing
1624 */
1625static int blk_trace_setup_queue(struct request_queue *q,
1626 struct block_device *bdev)
1627{
1628 struct blk_trace *bt = NULL;
1629 int ret = -ENOMEM;
1630
1631 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1632 if (!bt)
1633 return -ENOMEM;
1634
1635 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1636 if (!bt->msg_data)
1637 goto free_bt;
1638
1639 bt->dev = bdev->bd_dev;
1640 bt->act_mask = (u16)-1;
1641
1642 blk_trace_setup_lba(bt, bdev);
1643
1644 rcu_assign_pointer(q->blk_trace, bt);
1645 get_probe_ref();
1646 return 0;
1647
1648free_bt:
1649 blk_trace_free(bt);
1650 return ret;
1651}
1652
1653/*
1654 * sysfs interface to enable and configure tracing
1655 */
1656
1657static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1658 struct device_attribute *attr,
1659 char *buf);
1660static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1661 struct device_attribute *attr,
1662 const char *buf, size_t count);
1663#define BLK_TRACE_DEVICE_ATTR(_name) \
1664 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1665 sysfs_blk_trace_attr_show, \
1666 sysfs_blk_trace_attr_store)
1667
1668static BLK_TRACE_DEVICE_ATTR(enable);
1669static BLK_TRACE_DEVICE_ATTR(act_mask);
1670static BLK_TRACE_DEVICE_ATTR(pid);
1671static BLK_TRACE_DEVICE_ATTR(start_lba);
1672static BLK_TRACE_DEVICE_ATTR(end_lba);
1673
1674static struct attribute *blk_trace_attrs[] = {
1675 &dev_attr_enable.attr,
1676 &dev_attr_act_mask.attr,
1677 &dev_attr_pid.attr,
1678 &dev_attr_start_lba.attr,
1679 &dev_attr_end_lba.attr,
1680 NULL
1681};
1682
1683struct attribute_group blk_trace_attr_group = {
1684 .name = "trace",
1685 .attrs = blk_trace_attrs,
1686};
1687
1688static const struct {
1689 int mask;
1690 const char *str;
1691} mask_maps[] = {
1692 { BLK_TC_READ, "read" },
1693 { BLK_TC_WRITE, "write" },
1694 { BLK_TC_FLUSH, "flush" },
1695 { BLK_TC_SYNC, "sync" },
1696 { BLK_TC_QUEUE, "queue" },
1697 { BLK_TC_REQUEUE, "requeue" },
1698 { BLK_TC_ISSUE, "issue" },
1699 { BLK_TC_COMPLETE, "complete" },
1700 { BLK_TC_FS, "fs" },
1701 { BLK_TC_PC, "pc" },
1702 { BLK_TC_NOTIFY, "notify" },
1703 { BLK_TC_AHEAD, "ahead" },
1704 { BLK_TC_META, "meta" },
1705 { BLK_TC_DISCARD, "discard" },
1706 { BLK_TC_DRV_DATA, "drv_data" },
1707 { BLK_TC_FUA, "fua" },
1708};
1709
1710static int blk_trace_str2mask(const char *str)
1711{
1712 int i;
1713 int mask = 0;
1714 char *buf, *s, *token;
1715
1716 buf = kstrdup(str, GFP_KERNEL);
1717 if (buf == NULL)
1718 return -ENOMEM;
1719 s = strstrip(buf);
1720
1721 while (1) {
1722 token = strsep(&s, ",");
1723 if (token == NULL)
1724 break;
1725
1726 if (*token == '\0')
1727 continue;
1728
1729 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1730 if (strcasecmp(token, mask_maps[i].str) == 0) {
1731 mask |= mask_maps[i].mask;
1732 break;
1733 }
1734 }
1735 if (i == ARRAY_SIZE(mask_maps)) {
1736 mask = -EINVAL;
1737 break;
1738 }
1739 }
1740 kfree(buf);
1741
1742 return mask;
1743}
1744
1745static ssize_t blk_trace_mask2str(char *buf, int mask)
1746{
1747 int i;
1748 char *p = buf;
1749
1750 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1751 if (mask & mask_maps[i].mask) {
1752 p += sprintf(p, "%s%s",
1753 (p == buf) ? "" : ",", mask_maps[i].str);
1754 }
1755 }
1756 *p++ = '\n';
1757
1758 return p - buf;
1759}
1760
1761static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1762 struct device_attribute *attr,
1763 char *buf)
1764{
1765 struct block_device *bdev = dev_to_bdev(dev);
1766 struct request_queue *q = bdev_get_queue(bdev);
1767 struct blk_trace *bt;
1768 ssize_t ret = -ENXIO;
1769
1770 mutex_lock(&q->debugfs_mutex);
1771
1772 bt = rcu_dereference_protected(q->blk_trace,
1773 lockdep_is_held(&q->debugfs_mutex));
1774 if (attr == &dev_attr_enable) {
1775 ret = sprintf(buf, "%u\n", !!bt);
1776 goto out_unlock_bdev;
1777 }
1778
1779 if (bt == NULL)
1780 ret = sprintf(buf, "disabled\n");
1781 else if (attr == &dev_attr_act_mask)
1782 ret = blk_trace_mask2str(buf, bt->act_mask);
1783 else if (attr == &dev_attr_pid)
1784 ret = sprintf(buf, "%u\n", bt->pid);
1785 else if (attr == &dev_attr_start_lba)
1786 ret = sprintf(buf, "%llu\n", bt->start_lba);
1787 else if (attr == &dev_attr_end_lba)
1788 ret = sprintf(buf, "%llu\n", bt->end_lba);
1789
1790out_unlock_bdev:
1791 mutex_unlock(&q->debugfs_mutex);
1792 return ret;
1793}
1794
1795static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1796 struct device_attribute *attr,
1797 const char *buf, size_t count)
1798{
1799 struct block_device *bdev = dev_to_bdev(dev);
1800 struct request_queue *q = bdev_get_queue(bdev);
1801 struct blk_trace *bt;
1802 u64 value;
1803 ssize_t ret = -EINVAL;
1804
1805 if (count == 0)
1806 goto out;
1807
1808 if (attr == &dev_attr_act_mask) {
1809 if (kstrtoull(buf, 0, &value)) {
1810 /* Assume it is a list of trace category names */
1811 ret = blk_trace_str2mask(buf);
1812 if (ret < 0)
1813 goto out;
1814 value = ret;
1815 }
1816 } else {
1817 if (kstrtoull(buf, 0, &value))
1818 goto out;
1819 }
1820
1821 mutex_lock(&q->debugfs_mutex);
1822
1823 bt = rcu_dereference_protected(q->blk_trace,
1824 lockdep_is_held(&q->debugfs_mutex));
1825 if (attr == &dev_attr_enable) {
1826 if (!!value == !!bt) {
1827 ret = 0;
1828 goto out_unlock_bdev;
1829 }
1830 if (value)
1831 ret = blk_trace_setup_queue(q, bdev);
1832 else
1833 ret = blk_trace_remove_queue(q);
1834 goto out_unlock_bdev;
1835 }
1836
1837 ret = 0;
1838 if (bt == NULL) {
1839 ret = blk_trace_setup_queue(q, bdev);
1840 bt = rcu_dereference_protected(q->blk_trace,
1841 lockdep_is_held(&q->debugfs_mutex));
1842 }
1843
1844 if (ret == 0) {
1845 if (attr == &dev_attr_act_mask)
1846 bt->act_mask = value;
1847 else if (attr == &dev_attr_pid)
1848 bt->pid = value;
1849 else if (attr == &dev_attr_start_lba)
1850 bt->start_lba = value;
1851 else if (attr == &dev_attr_end_lba)
1852 bt->end_lba = value;
1853 }
1854
1855out_unlock_bdev:
1856 mutex_unlock(&q->debugfs_mutex);
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
1875/**
1876 * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string.
1877 * @rwbs: buffer to be filled
1878 * @op: REQ_OP_XXX for the tracepoint
1879 *
1880 * Description:
1881 * Maps the REQ_OP_XXX to character and fills the buffer provided by the
1882 * caller with resulting string.
1883 *
1884 **/
1885void blk_fill_rwbs(char *rwbs, unsigned int op)
1886{
1887 int i = 0;
1888
1889 if (op & REQ_PREFLUSH)
1890 rwbs[i++] = 'F';
1891
1892 switch (op & REQ_OP_MASK) {
1893 case REQ_OP_WRITE:
1894 case REQ_OP_WRITE_SAME:
1895 rwbs[i++] = 'W';
1896 break;
1897 case REQ_OP_DISCARD:
1898 rwbs[i++] = 'D';
1899 break;
1900 case REQ_OP_SECURE_ERASE:
1901 rwbs[i++] = 'D';
1902 rwbs[i++] = 'E';
1903 break;
1904 case REQ_OP_FLUSH:
1905 rwbs[i++] = 'F';
1906 break;
1907 case REQ_OP_READ:
1908 rwbs[i++] = 'R';
1909 break;
1910 default:
1911 rwbs[i++] = 'N';
1912 }
1913
1914 if (op & REQ_FUA)
1915 rwbs[i++] = 'F';
1916 if (op & REQ_RAHEAD)
1917 rwbs[i++] = 'A';
1918 if (op & REQ_SYNC)
1919 rwbs[i++] = 'S';
1920 if (op & REQ_META)
1921 rwbs[i++] = 'M';
1922
1923 rwbs[i] = '\0';
1924}
1925EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1926
1927#endif /* CONFIG_EVENT_TRACING */
1928