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 if (!dir)
516 goto err;
517
518 bt->dev = dev;
519 atomic_set(&bt->dropped, 0);
520 INIT_LIST_HEAD(&bt->running_list);
521
522 ret = -EIO;
523 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
524 &blk_dropped_fops);
525 if (!bt->dropped_file)
526 goto err;
527
528 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
529 if (!bt->msg_file)
530 goto err;
531
532 bt->rchan = relay_open("trace", dir, buts->buf_size,
533 buts->buf_nr, &blk_relay_callbacks, bt);
534 if (!bt->rchan)
535 goto err;
536
537 bt->act_mask = buts->act_mask;
538 if (!bt->act_mask)
539 bt->act_mask = (u16) -1;
540
541 blk_trace_setup_lba(bt, bdev);
542
543 /* overwrite with user settings */
544 if (buts->start_lba)
545 bt->start_lba = buts->start_lba;
546 if (buts->end_lba)
547 bt->end_lba = buts->end_lba;
548
549 bt->pid = buts->pid;
550 bt->trace_state = Blktrace_setup;
551
552 ret = -EBUSY;
553 if (cmpxchg(&q->blk_trace, NULL, bt))
554 goto err;
555
556 get_probe_ref();
557
558 ret = 0;
559err:
560 if (dir && !bt->dir)
561 dput(dir);
562 if (ret)
563 blk_trace_free(bt);
564 return ret;
565}
566
567static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
568 struct block_device *bdev, char __user *arg)
569{
570 struct blk_user_trace_setup buts;
571 int ret;
572
573 ret = copy_from_user(&buts, arg, sizeof(buts));
574 if (ret)
575 return -EFAULT;
576
577 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
578 if (ret)
579 return ret;
580
581 if (copy_to_user(arg, &buts, sizeof(buts))) {
582 __blk_trace_remove(q);
583 return -EFAULT;
584 }
585 return 0;
586}
587
588int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
589 struct block_device *bdev,
590 char __user *arg)
591{
592 int ret;
593
594 mutex_lock(&q->blk_trace_mutex);
595 ret = __blk_trace_setup(q, name, dev, bdev, arg);
596 mutex_unlock(&q->blk_trace_mutex);
597
598 return ret;
599}
600EXPORT_SYMBOL_GPL(blk_trace_setup);
601
602#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
603static int compat_blk_trace_setup(struct request_queue *q, char *name,
604 dev_t dev, struct block_device *bdev,
605 char __user *arg)
606{
607 struct blk_user_trace_setup buts;
608 struct compat_blk_user_trace_setup cbuts;
609 int ret;
610
611 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
612 return -EFAULT;
613
614 buts = (struct blk_user_trace_setup) {
615 .act_mask = cbuts.act_mask,
616 .buf_size = cbuts.buf_size,
617 .buf_nr = cbuts.buf_nr,
618 .start_lba = cbuts.start_lba,
619 .end_lba = cbuts.end_lba,
620 .pid = cbuts.pid,
621 };
622
623 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
624 if (ret)
625 return ret;
626
627 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
628 __blk_trace_remove(q);
629 return -EFAULT;
630 }
631
632 return 0;
633}
634#endif
635
636static int __blk_trace_startstop(struct request_queue *q, int start)
637{
638 int ret;
639 struct blk_trace *bt = q->blk_trace;
640
641 if (bt == NULL)
642 return -EINVAL;
643
644 /*
645 * For starting a trace, we can transition from a setup or stopped
646 * trace. For stopping a trace, the state must be running
647 */
648 ret = -EINVAL;
649 if (start) {
650 if (bt->trace_state == Blktrace_setup ||
651 bt->trace_state == Blktrace_stopped) {
652 blktrace_seq++;
653 smp_mb();
654 bt->trace_state = Blktrace_running;
655 spin_lock_irq(&running_trace_lock);
656 list_add(&bt->running_list, &running_trace_list);
657 spin_unlock_irq(&running_trace_lock);
658
659 trace_note_time(bt);
660 ret = 0;
661 }
662 } else {
663 if (bt->trace_state == Blktrace_running) {
664 bt->trace_state = Blktrace_stopped;
665 spin_lock_irq(&running_trace_lock);
666 list_del_init(&bt->running_list);
667 spin_unlock_irq(&running_trace_lock);
668 relay_flush(bt->rchan);
669 ret = 0;
670 }
671 }
672
673 return ret;
674}
675
676int blk_trace_startstop(struct request_queue *q, int start)
677{
678 int ret;
679
680 mutex_lock(&q->blk_trace_mutex);
681 ret = __blk_trace_startstop(q, start);
682 mutex_unlock(&q->blk_trace_mutex);
683
684 return ret;
685}
686EXPORT_SYMBOL_GPL(blk_trace_startstop);
687
688/*
689 * When reading or writing the blktrace sysfs files, the references to the
690 * opened sysfs or device files should prevent the underlying block device
691 * from being removed. So no further delete protection is really needed.
692 */
693
694/**
695 * blk_trace_ioctl: - handle the ioctls associated with tracing
696 * @bdev: the block device
697 * @cmd: the ioctl cmd
698 * @arg: the argument data, if any
699 *
700 **/
701int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
702{
703 struct request_queue *q;
704 int ret, start = 0;
705 char b[BDEVNAME_SIZE];
706
707 q = bdev_get_queue(bdev);
708 if (!q)
709 return -ENXIO;
710
711 mutex_lock(&q->blk_trace_mutex);
712
713 switch (cmd) {
714 case BLKTRACESETUP:
715 bdevname(bdev, b);
716 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
717 break;
718#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
719 case BLKTRACESETUP32:
720 bdevname(bdev, b);
721 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
722 break;
723#endif
724 case BLKTRACESTART:
725 start = 1;
726 /* fall through */
727 case BLKTRACESTOP:
728 ret = __blk_trace_startstop(q, start);
729 break;
730 case BLKTRACETEARDOWN:
731 ret = __blk_trace_remove(q);
732 break;
733 default:
734 ret = -ENOTTY;
735 break;
736 }
737
738 mutex_unlock(&q->blk_trace_mutex);
739 return ret;
740}
741
742/**
743 * blk_trace_shutdown: - stop and cleanup trace structures
744 * @q: the request queue associated with the device
745 *
746 **/
747void blk_trace_shutdown(struct request_queue *q)
748{
749 mutex_lock(&q->blk_trace_mutex);
750
751 if (q->blk_trace) {
752 __blk_trace_startstop(q, 0);
753 __blk_trace_remove(q);
754 }
755
756 mutex_unlock(&q->blk_trace_mutex);
757}
758
759#ifdef CONFIG_BLK_CGROUP
760static union kernfs_node_id *
761blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
762{
763 struct blk_trace *bt = q->blk_trace;
764
765 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
766 return NULL;
767
768 if (!bio->bi_blkg)
769 return NULL;
770 return cgroup_get_kernfs_id(bio_blkcg(bio)->css.cgroup);
771}
772#else
773static union kernfs_node_id *
774blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
775{
776 return NULL;
777}
778#endif
779
780static union kernfs_node_id *
781blk_trace_request_get_cgid(struct request_queue *q, struct request *rq)
782{
783 if (!rq->bio)
784 return NULL;
785 /* Use the first bio */
786 return blk_trace_bio_get_cgid(q, rq->bio);
787}
788
789/*
790 * blktrace probes
791 */
792
793/**
794 * blk_add_trace_rq - Add a trace for a request oriented action
795 * @rq: the source request
796 * @error: return status to log
797 * @nr_bytes: number of completed bytes
798 * @what: the action
799 * @cgid: the cgroup info
800 *
801 * Description:
802 * Records an action against a request. Will log the bio offset + size.
803 *
804 **/
805static void blk_add_trace_rq(struct request *rq, int error,
806 unsigned int nr_bytes, u32 what,
807 union kernfs_node_id *cgid)
808{
809 struct blk_trace *bt = rq->q->blk_trace;
810
811 if (likely(!bt))
812 return;
813
814 if (blk_rq_is_passthrough(rq))
815 what |= BLK_TC_ACT(BLK_TC_PC);
816 else
817 what |= BLK_TC_ACT(BLK_TC_FS);
818
819 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
820 rq->cmd_flags, what, error, 0, NULL, cgid);
821}
822
823static void blk_add_trace_rq_insert(void *ignore,
824 struct request_queue *q, struct request *rq)
825{
826 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
827 blk_trace_request_get_cgid(q, rq));
828}
829
830static void blk_add_trace_rq_issue(void *ignore,
831 struct request_queue *q, struct request *rq)
832{
833 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
834 blk_trace_request_get_cgid(q, rq));
835}
836
837static void blk_add_trace_rq_requeue(void *ignore,
838 struct request_queue *q,
839 struct request *rq)
840{
841 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
842 blk_trace_request_get_cgid(q, rq));
843}
844
845static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
846 int error, unsigned int nr_bytes)
847{
848 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
849 blk_trace_request_get_cgid(rq->q, rq));
850}
851
852/**
853 * blk_add_trace_bio - Add a trace for a bio oriented action
854 * @q: queue the io is for
855 * @bio: the source bio
856 * @what: the action
857 * @error: error, if any
858 *
859 * Description:
860 * Records an action against a bio. Will log the bio offset + size.
861 *
862 **/
863static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
864 u32 what, int error)
865{
866 struct blk_trace *bt = q->blk_trace;
867
868 if (likely(!bt))
869 return;
870
871 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
872 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
873 blk_trace_bio_get_cgid(q, bio));
874}
875
876static void blk_add_trace_bio_bounce(void *ignore,
877 struct request_queue *q, struct bio *bio)
878{
879 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
880}
881
882static void blk_add_trace_bio_complete(void *ignore,
883 struct request_queue *q, struct bio *bio,
884 int error)
885{
886 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
887}
888
889static void blk_add_trace_bio_backmerge(void *ignore,
890 struct request_queue *q,
891 struct request *rq,
892 struct bio *bio)
893{
894 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
895}
896
897static void blk_add_trace_bio_frontmerge(void *ignore,
898 struct request_queue *q,
899 struct request *rq,
900 struct bio *bio)
901{
902 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
903}
904
905static void blk_add_trace_bio_queue(void *ignore,
906 struct request_queue *q, struct bio *bio)
907{
908 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
909}
910
911static void blk_add_trace_getrq(void *ignore,
912 struct request_queue *q,
913 struct bio *bio, int rw)
914{
915 if (bio)
916 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
917 else {
918 struct blk_trace *bt = q->blk_trace;
919
920 if (bt)
921 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
922 NULL, NULL);
923 }
924}
925
926
927static void blk_add_trace_sleeprq(void *ignore,
928 struct request_queue *q,
929 struct bio *bio, int rw)
930{
931 if (bio)
932 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
933 else {
934 struct blk_trace *bt = q->blk_trace;
935
936 if (bt)
937 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
938 0, 0, NULL, NULL);
939 }
940}
941
942static void blk_add_trace_plug(void *ignore, struct request_queue *q)
943{
944 struct blk_trace *bt = q->blk_trace;
945
946 if (bt)
947 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, NULL);
948}
949
950static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
951 unsigned int depth, bool explicit)
952{
953 struct blk_trace *bt = q->blk_trace;
954
955 if (bt) {
956 __be64 rpdu = cpu_to_be64(depth);
957 u32 what;
958
959 if (explicit)
960 what = BLK_TA_UNPLUG_IO;
961 else
962 what = BLK_TA_UNPLUG_TIMER;
963
964 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, NULL);
965 }
966}
967
968static void blk_add_trace_split(void *ignore,
969 struct request_queue *q, struct bio *bio,
970 unsigned int pdu)
971{
972 struct blk_trace *bt = q->blk_trace;
973
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, bio->bi_status, sizeof(rpdu),
980 &rpdu, blk_trace_bio_get_cgid(q, bio));
981 }
982}
983
984/**
985 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
986 * @ignore: trace callback data parameter (not used)
987 * @q: queue the io is for
988 * @bio: the source bio
989 * @dev: target device
990 * @from: source sector
991 *
992 * Description:
993 * Device mapper or raid target sometimes need to split a bio because
994 * it spans a stripe (or similar). Add a trace for that action.
995 *
996 **/
997static void blk_add_trace_bio_remap(void *ignore,
998 struct request_queue *q, struct bio *bio,
999 dev_t dev, sector_t from)
1000{
1001 struct blk_trace *bt = q->blk_trace;
1002 struct blk_io_trace_remap r;
1003
1004 if (likely(!bt))
1005 return;
1006
1007 r.device_from = cpu_to_be32(dev);
1008 r.device_to = cpu_to_be32(bio_dev(bio));
1009 r.sector_from = cpu_to_be64(from);
1010
1011 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1012 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status,
1013 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1014}
1015
1016/**
1017 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1018 * @ignore: trace callback data parameter (not used)
1019 * @q: queue the io is for
1020 * @rq: the source request
1021 * @dev: target device
1022 * @from: source sector
1023 *
1024 * Description:
1025 * Device mapper remaps request to other devices.
1026 * Add a trace for that action.
1027 *
1028 **/
1029static void blk_add_trace_rq_remap(void *ignore,
1030 struct request_queue *q,
1031 struct request *rq, dev_t dev,
1032 sector_t from)
1033{
1034 struct blk_trace *bt = q->blk_trace;
1035 struct blk_io_trace_remap r;
1036
1037 if (likely(!bt))
1038 return;
1039
1040 r.device_from = cpu_to_be32(dev);
1041 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1042 r.sector_from = cpu_to_be64(from);
1043
1044 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1045 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1046 sizeof(r), &r, blk_trace_request_get_cgid(q, rq));
1047}
1048
1049/**
1050 * blk_add_driver_data - Add binary message with driver-specific data
1051 * @q: queue the io is for
1052 * @rq: io request
1053 * @data: driver-specific data
1054 * @len: length of driver-specific data
1055 *
1056 * Description:
1057 * Some drivers might want to write driver-specific data per request.
1058 *
1059 **/
1060void blk_add_driver_data(struct request_queue *q,
1061 struct request *rq,
1062 void *data, size_t len)
1063{
1064 struct blk_trace *bt = q->blk_trace;
1065
1066 if (likely(!bt))
1067 return;
1068
1069 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1070 BLK_TA_DRV_DATA, 0, len, data,
1071 blk_trace_request_get_cgid(q, rq));
1072}
1073EXPORT_SYMBOL_GPL(blk_add_driver_data);
1074
1075static void blk_register_tracepoints(void)
1076{
1077 int ret;
1078
1079 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1080 WARN_ON(ret);
1081 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1082 WARN_ON(ret);
1083 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1084 WARN_ON(ret);
1085 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1086 WARN_ON(ret);
1087 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1088 WARN_ON(ret);
1089 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1090 WARN_ON(ret);
1091 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1092 WARN_ON(ret);
1093 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1094 WARN_ON(ret);
1095 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1096 WARN_ON(ret);
1097 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1098 WARN_ON(ret);
1099 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1100 WARN_ON(ret);
1101 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1102 WARN_ON(ret);
1103 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1104 WARN_ON(ret);
1105 ret = register_trace_block_split(blk_add_trace_split, NULL);
1106 WARN_ON(ret);
1107 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1108 WARN_ON(ret);
1109 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1110 WARN_ON(ret);
1111}
1112
1113static void blk_unregister_tracepoints(void)
1114{
1115 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1116 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1117 unregister_trace_block_split(blk_add_trace_split, NULL);
1118 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1119 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1120 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1121 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1122 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1123 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1124 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1125 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1126 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1127 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1128 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1129 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1130 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1131
1132 tracepoint_synchronize_unregister();
1133}
1134
1135/*
1136 * struct blk_io_tracer formatting routines
1137 */
1138
1139static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1140{
1141 int i = 0;
1142 int tc = t->action >> BLK_TC_SHIFT;
1143
1144 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1145 rwbs[i++] = 'N';
1146 goto out;
1147 }
1148
1149 if (tc & BLK_TC_FLUSH)
1150 rwbs[i++] = 'F';
1151
1152 if (tc & BLK_TC_DISCARD)
1153 rwbs[i++] = 'D';
1154 else if (tc & BLK_TC_WRITE)
1155 rwbs[i++] = 'W';
1156 else if (t->bytes)
1157 rwbs[i++] = 'R';
1158 else
1159 rwbs[i++] = 'N';
1160
1161 if (tc & BLK_TC_FUA)
1162 rwbs[i++] = 'F';
1163 if (tc & BLK_TC_AHEAD)
1164 rwbs[i++] = 'A';
1165 if (tc & BLK_TC_SYNC)
1166 rwbs[i++] = 'S';
1167 if (tc & BLK_TC_META)
1168 rwbs[i++] = 'M';
1169out:
1170 rwbs[i] = '\0';
1171}
1172
1173static inline
1174const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1175{
1176 return (const struct blk_io_trace *)ent;
1177}
1178
1179static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1180{
1181 return (void *)(te_blk_io_trace(ent) + 1) +
1182 (has_cg ? sizeof(union kernfs_node_id) : 0);
1183}
1184
1185static inline const void *cgid_start(const struct trace_entry *ent)
1186{
1187 return (void *)(te_blk_io_trace(ent) + 1);
1188}
1189
1190static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1191{
1192 return te_blk_io_trace(ent)->pdu_len -
1193 (has_cg ? sizeof(union kernfs_node_id) : 0);
1194}
1195
1196static inline u32 t_action(const struct trace_entry *ent)
1197{
1198 return te_blk_io_trace(ent)->action;
1199}
1200
1201static inline u32 t_bytes(const struct trace_entry *ent)
1202{
1203 return te_blk_io_trace(ent)->bytes;
1204}
1205
1206static inline u32 t_sec(const struct trace_entry *ent)
1207{
1208 return te_blk_io_trace(ent)->bytes >> 9;
1209}
1210
1211static inline unsigned long long t_sector(const struct trace_entry *ent)
1212{
1213 return te_blk_io_trace(ent)->sector;
1214}
1215
1216static inline __u16 t_error(const struct trace_entry *ent)
1217{
1218 return te_blk_io_trace(ent)->error;
1219}
1220
1221static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1222{
1223 const __u64 *val = pdu_start(ent, has_cg);
1224 return be64_to_cpu(*val);
1225}
1226
1227static void get_pdu_remap(const struct trace_entry *ent,
1228 struct blk_io_trace_remap *r, bool has_cg)
1229{
1230 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1231 __u64 sector_from = __r->sector_from;
1232
1233 r->device_from = be32_to_cpu(__r->device_from);
1234 r->device_to = be32_to_cpu(__r->device_to);
1235 r->sector_from = be64_to_cpu(sector_from);
1236}
1237
1238typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1239 bool has_cg);
1240
1241static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1242 bool has_cg)
1243{
1244 char rwbs[RWBS_LEN];
1245 unsigned long long ts = iter->ts;
1246 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1247 unsigned secs = (unsigned long)ts;
1248 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1249
1250 fill_rwbs(rwbs, t);
1251
1252 trace_seq_printf(&iter->seq,
1253 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1254 MAJOR(t->device), MINOR(t->device), iter->cpu,
1255 secs, nsec_rem, iter->ent->pid, act, rwbs);
1256}
1257
1258static void blk_log_action(struct trace_iterator *iter, const char *act,
1259 bool has_cg)
1260{
1261 char rwbs[RWBS_LEN];
1262 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1263
1264 fill_rwbs(rwbs, t);
1265 if (has_cg) {
1266 const union kernfs_node_id *id = cgid_start(iter->ent);
1267
1268 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1269 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1270
1271 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1272 sizeof(blkcg_name_buf));
1273 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1274 MAJOR(t->device), MINOR(t->device),
1275 blkcg_name_buf, act, rwbs);
1276 } else
1277 trace_seq_printf(&iter->seq,
1278 "%3d,%-3d %x,%-x %2s %3s ",
1279 MAJOR(t->device), MINOR(t->device),
1280 id->ino, id->generation, act, rwbs);
1281 } else
1282 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1283 MAJOR(t->device), MINOR(t->device), act, rwbs);
1284}
1285
1286static void blk_log_dump_pdu(struct trace_seq *s,
1287 const struct trace_entry *ent, bool has_cg)
1288{
1289 const unsigned char *pdu_buf;
1290 int pdu_len;
1291 int i, end;
1292
1293 pdu_buf = pdu_start(ent, has_cg);
1294 pdu_len = pdu_real_len(ent, has_cg);
1295
1296 if (!pdu_len)
1297 return;
1298
1299 /* find the last zero that needs to be printed */
1300 for (end = pdu_len - 1; end >= 0; end--)
1301 if (pdu_buf[end])
1302 break;
1303 end++;
1304
1305 trace_seq_putc(s, '(');
1306
1307 for (i = 0; i < pdu_len; i++) {
1308
1309 trace_seq_printf(s, "%s%02x",
1310 i == 0 ? "" : " ", pdu_buf[i]);
1311
1312 /*
1313 * stop when the rest is just zeroes and indicate so
1314 * with a ".." appended
1315 */
1316 if (i == end && end != pdu_len - 1) {
1317 trace_seq_puts(s, " ..) ");
1318 return;
1319 }
1320 }
1321
1322 trace_seq_puts(s, ") ");
1323}
1324
1325static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1326{
1327 char cmd[TASK_COMM_LEN];
1328
1329 trace_find_cmdline(ent->pid, cmd);
1330
1331 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1332 trace_seq_printf(s, "%u ", t_bytes(ent));
1333 blk_log_dump_pdu(s, ent, has_cg);
1334 trace_seq_printf(s, "[%s]\n", cmd);
1335 } else {
1336 if (t_sec(ent))
1337 trace_seq_printf(s, "%llu + %u [%s]\n",
1338 t_sector(ent), t_sec(ent), cmd);
1339 else
1340 trace_seq_printf(s, "[%s]\n", cmd);
1341 }
1342}
1343
1344static void blk_log_with_error(struct trace_seq *s,
1345 const struct trace_entry *ent, bool has_cg)
1346{
1347 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1348 blk_log_dump_pdu(s, ent, has_cg);
1349 trace_seq_printf(s, "[%d]\n", t_error(ent));
1350 } else {
1351 if (t_sec(ent))
1352 trace_seq_printf(s, "%llu + %u [%d]\n",
1353 t_sector(ent),
1354 t_sec(ent), t_error(ent));
1355 else
1356 trace_seq_printf(s, "%llu [%d]\n",
1357 t_sector(ent), t_error(ent));
1358 }
1359}
1360
1361static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1362{
1363 struct blk_io_trace_remap r = { .device_from = 0, };
1364
1365 get_pdu_remap(ent, &r, has_cg);
1366 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1367 t_sector(ent), t_sec(ent),
1368 MAJOR(r.device_from), MINOR(r.device_from),
1369 (unsigned long long)r.sector_from);
1370}
1371
1372static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1373{
1374 char cmd[TASK_COMM_LEN];
1375
1376 trace_find_cmdline(ent->pid, cmd);
1377
1378 trace_seq_printf(s, "[%s]\n", cmd);
1379}
1380
1381static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1382{
1383 char cmd[TASK_COMM_LEN];
1384
1385 trace_find_cmdline(ent->pid, cmd);
1386
1387 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1388}
1389
1390static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1391{
1392 char cmd[TASK_COMM_LEN];
1393
1394 trace_find_cmdline(ent->pid, cmd);
1395
1396 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1397 get_pdu_int(ent, has_cg), cmd);
1398}
1399
1400static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1401 bool has_cg)
1402{
1403
1404 trace_seq_putmem(s, pdu_start(ent, has_cg),
1405 pdu_real_len(ent, has_cg));
1406 trace_seq_putc(s, '\n');
1407}
1408
1409/*
1410 * struct tracer operations
1411 */
1412
1413static void blk_tracer_print_header(struct seq_file *m)
1414{
1415 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1416 return;
1417 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1418 "# | | | | | |\n");
1419}
1420
1421static void blk_tracer_start(struct trace_array *tr)
1422{
1423 blk_tracer_enabled = true;
1424}
1425
1426static int blk_tracer_init(struct trace_array *tr)
1427{
1428 blk_tr = tr;
1429 blk_tracer_start(tr);
1430 return 0;
1431}
1432
1433static void blk_tracer_stop(struct trace_array *tr)
1434{
1435 blk_tracer_enabled = false;
1436}
1437
1438static void blk_tracer_reset(struct trace_array *tr)
1439{
1440 blk_tracer_stop(tr);
1441}
1442
1443static const struct {
1444 const char *act[2];
1445 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1446 bool has_cg);
1447} what2act[] = {
1448 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1449 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1450 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1451 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1452 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1453 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1454 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1455 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1456 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1457 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1458 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1459 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1460 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1461 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1462 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1463};
1464
1465static enum print_line_t print_one_line(struct trace_iterator *iter,
1466 bool classic)
1467{
1468 struct trace_array *tr = iter->tr;
1469 struct trace_seq *s = &iter->seq;
1470 const struct blk_io_trace *t;
1471 u16 what;
1472 bool long_act;
1473 blk_log_action_t *log_action;
1474 bool has_cg;
1475
1476 t = te_blk_io_trace(iter->ent);
1477 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1478 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1479 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1480 has_cg = t->action & __BLK_TA_CGROUP;
1481
1482 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1483 log_action(iter, long_act ? "message" : "m", has_cg);
1484 blk_log_msg(s, iter->ent, has_cg);
1485 return trace_handle_return(s);
1486 }
1487
1488 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1489 trace_seq_printf(s, "Unknown action %x\n", what);
1490 else {
1491 log_action(iter, what2act[what].act[long_act], has_cg);
1492 what2act[what].print(s, iter->ent, has_cg);
1493 }
1494
1495 return trace_handle_return(s);
1496}
1497
1498static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1499 int flags, struct trace_event *event)
1500{
1501 return print_one_line(iter, false);
1502}
1503
1504static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1505{
1506 struct trace_seq *s = &iter->seq;
1507 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1508 const int offset = offsetof(struct blk_io_trace, sector);
1509 struct blk_io_trace old = {
1510 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1511 .time = iter->ts,
1512 };
1513
1514 trace_seq_putmem(s, &old, offset);
1515 trace_seq_putmem(s, &t->sector,
1516 sizeof(old) - offset + t->pdu_len);
1517}
1518
1519static enum print_line_t
1520blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1521 struct trace_event *event)
1522{
1523 blk_trace_synthesize_old_trace(iter);
1524
1525 return trace_handle_return(&iter->seq);
1526}
1527
1528static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1529{
1530 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1531 return TRACE_TYPE_UNHANDLED;
1532
1533 return print_one_line(iter, true);
1534}
1535
1536static int
1537blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1538{
1539 /* don't output context-info for blk_classic output */
1540 if (bit == TRACE_BLK_OPT_CLASSIC) {
1541 if (set)
1542 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1543 else
1544 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1545 }
1546 return 0;
1547}
1548
1549static struct tracer blk_tracer __read_mostly = {
1550 .name = "blk",
1551 .init = blk_tracer_init,
1552 .reset = blk_tracer_reset,
1553 .start = blk_tracer_start,
1554 .stop = blk_tracer_stop,
1555 .print_header = blk_tracer_print_header,
1556 .print_line = blk_tracer_print_line,
1557 .flags = &blk_tracer_flags,
1558 .set_flag = blk_tracer_set_flag,
1559};
1560
1561static struct trace_event_functions trace_blk_event_funcs = {
1562 .trace = blk_trace_event_print,
1563 .binary = blk_trace_event_print_binary,
1564};
1565
1566static struct trace_event trace_blk_event = {
1567 .type = TRACE_BLK,
1568 .funcs = &trace_blk_event_funcs,
1569};
1570
1571static int __init init_blk_tracer(void)
1572{
1573 if (!register_trace_event(&trace_blk_event)) {
1574 pr_warn("Warning: could not register block events\n");
1575 return 1;
1576 }
1577
1578 if (register_tracer(&blk_tracer) != 0) {
1579 pr_warn("Warning: could not register the block tracer\n");
1580 unregister_trace_event(&trace_blk_event);
1581 return 1;
1582 }
1583
1584 return 0;
1585}
1586
1587device_initcall(init_blk_tracer);
1588
1589static int blk_trace_remove_queue(struct request_queue *q)
1590{
1591 struct blk_trace *bt;
1592
1593 bt = xchg(&q->blk_trace, NULL);
1594 if (bt == NULL)
1595 return -EINVAL;
1596
1597 put_probe_ref();
1598 blk_trace_free(bt);
1599 return 0;
1600}
1601
1602/*
1603 * Setup everything required to start tracing
1604 */
1605static int blk_trace_setup_queue(struct request_queue *q,
1606 struct block_device *bdev)
1607{
1608 struct blk_trace *bt = NULL;
1609 int ret = -ENOMEM;
1610
1611 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1612 if (!bt)
1613 return -ENOMEM;
1614
1615 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1616 if (!bt->msg_data)
1617 goto free_bt;
1618
1619 bt->dev = bdev->bd_dev;
1620 bt->act_mask = (u16)-1;
1621
1622 blk_trace_setup_lba(bt, bdev);
1623
1624 ret = -EBUSY;
1625 if (cmpxchg(&q->blk_trace, NULL, bt))
1626 goto free_bt;
1627
1628 get_probe_ref();
1629 return 0;
1630
1631free_bt:
1632 blk_trace_free(bt);
1633 return ret;
1634}
1635
1636/*
1637 * sysfs interface to enable and configure tracing
1638 */
1639
1640static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1641 struct device_attribute *attr,
1642 char *buf);
1643static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1644 struct device_attribute *attr,
1645 const char *buf, size_t count);
1646#define BLK_TRACE_DEVICE_ATTR(_name) \
1647 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1648 sysfs_blk_trace_attr_show, \
1649 sysfs_blk_trace_attr_store)
1650
1651static BLK_TRACE_DEVICE_ATTR(enable);
1652static BLK_TRACE_DEVICE_ATTR(act_mask);
1653static BLK_TRACE_DEVICE_ATTR(pid);
1654static BLK_TRACE_DEVICE_ATTR(start_lba);
1655static BLK_TRACE_DEVICE_ATTR(end_lba);
1656
1657static struct attribute *blk_trace_attrs[] = {
1658 &dev_attr_enable.attr,
1659 &dev_attr_act_mask.attr,
1660 &dev_attr_pid.attr,
1661 &dev_attr_start_lba.attr,
1662 &dev_attr_end_lba.attr,
1663 NULL
1664};
1665
1666struct attribute_group blk_trace_attr_group = {
1667 .name = "trace",
1668 .attrs = blk_trace_attrs,
1669};
1670
1671static const struct {
1672 int mask;
1673 const char *str;
1674} mask_maps[] = {
1675 { BLK_TC_READ, "read" },
1676 { BLK_TC_WRITE, "write" },
1677 { BLK_TC_FLUSH, "flush" },
1678 { BLK_TC_SYNC, "sync" },
1679 { BLK_TC_QUEUE, "queue" },
1680 { BLK_TC_REQUEUE, "requeue" },
1681 { BLK_TC_ISSUE, "issue" },
1682 { BLK_TC_COMPLETE, "complete" },
1683 { BLK_TC_FS, "fs" },
1684 { BLK_TC_PC, "pc" },
1685 { BLK_TC_NOTIFY, "notify" },
1686 { BLK_TC_AHEAD, "ahead" },
1687 { BLK_TC_META, "meta" },
1688 { BLK_TC_DISCARD, "discard" },
1689 { BLK_TC_DRV_DATA, "drv_data" },
1690 { BLK_TC_FUA, "fua" },
1691};
1692
1693static int blk_trace_str2mask(const char *str)
1694{
1695 int i;
1696 int mask = 0;
1697 char *buf, *s, *token;
1698
1699 buf = kstrdup(str, GFP_KERNEL);
1700 if (buf == NULL)
1701 return -ENOMEM;
1702 s = strstrip(buf);
1703
1704 while (1) {
1705 token = strsep(&s, ",");
1706 if (token == NULL)
1707 break;
1708
1709 if (*token == '\0')
1710 continue;
1711
1712 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1713 if (strcasecmp(token, mask_maps[i].str) == 0) {
1714 mask |= mask_maps[i].mask;
1715 break;
1716 }
1717 }
1718 if (i == ARRAY_SIZE(mask_maps)) {
1719 mask = -EINVAL;
1720 break;
1721 }
1722 }
1723 kfree(buf);
1724
1725 return mask;
1726}
1727
1728static ssize_t blk_trace_mask2str(char *buf, int mask)
1729{
1730 int i;
1731 char *p = buf;
1732
1733 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1734 if (mask & mask_maps[i].mask) {
1735 p += sprintf(p, "%s%s",
1736 (p == buf) ? "" : ",", mask_maps[i].str);
1737 }
1738 }
1739 *p++ = '\n';
1740
1741 return p - buf;
1742}
1743
1744static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1745{
1746 if (bdev->bd_disk == NULL)
1747 return NULL;
1748
1749 return bdev_get_queue(bdev);
1750}
1751
1752static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1753 struct device_attribute *attr,
1754 char *buf)
1755{
1756 struct hd_struct *p = dev_to_part(dev);
1757 struct request_queue *q;
1758 struct block_device *bdev;
1759 ssize_t ret = -ENXIO;
1760
1761 bdev = bdget(part_devt(p));
1762 if (bdev == NULL)
1763 goto out;
1764
1765 q = blk_trace_get_queue(bdev);
1766 if (q == NULL)
1767 goto out_bdput;
1768
1769 mutex_lock(&q->blk_trace_mutex);
1770
1771 if (attr == &dev_attr_enable) {
1772 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1773 goto out_unlock_bdev;
1774 }
1775
1776 if (q->blk_trace == NULL)
1777 ret = sprintf(buf, "disabled\n");
1778 else if (attr == &dev_attr_act_mask)
1779 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1780 else if (attr == &dev_attr_pid)
1781 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1782 else if (attr == &dev_attr_start_lba)
1783 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1784 else if (attr == &dev_attr_end_lba)
1785 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1786
1787out_unlock_bdev:
1788 mutex_unlock(&q->blk_trace_mutex);
1789out_bdput:
1790 bdput(bdev);
1791out:
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;
1800 struct request_queue *q;
1801 struct hd_struct *p;
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 if (kstrtoull(buf, 0, &value))
1817 goto out;
1818
1819 ret = -ENXIO;
1820
1821 p = dev_to_part(dev);
1822 bdev = bdget(part_devt(p));
1823 if (bdev == NULL)
1824 goto out;
1825
1826 q = blk_trace_get_queue(bdev);
1827 if (q == NULL)
1828 goto out_bdput;
1829
1830 mutex_lock(&q->blk_trace_mutex);
1831
1832 if (attr == &dev_attr_enable) {
1833 if (!!value == !!q->blk_trace) {
1834 ret = 0;
1835 goto out_unlock_bdev;
1836 }
1837 if (value)
1838 ret = blk_trace_setup_queue(q, bdev);
1839 else
1840 ret = blk_trace_remove_queue(q);
1841 goto out_unlock_bdev;
1842 }
1843
1844 ret = 0;
1845 if (q->blk_trace == NULL)
1846 ret = blk_trace_setup_queue(q, bdev);
1847
1848 if (ret == 0) {
1849 if (attr == &dev_attr_act_mask)
1850 q->blk_trace->act_mask = value;
1851 else if (attr == &dev_attr_pid)
1852 q->blk_trace->pid = value;
1853 else if (attr == &dev_attr_start_lba)
1854 q->blk_trace->start_lba = value;
1855 else if (attr == &dev_attr_end_lba)
1856 q->blk_trace->end_lba = value;
1857 }
1858
1859out_unlock_bdev:
1860 mutex_unlock(&q->blk_trace_mutex);
1861out_bdput:
1862 bdput(bdev);
1863out:
1864 return ret ? ret : count;
1865}
1866
1867int blk_trace_init_sysfs(struct device *dev)
1868{
1869 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1870}
1871
1872void blk_trace_remove_sysfs(struct device *dev)
1873{
1874 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1875}
1876
1877#endif /* CONFIG_BLK_DEV_IO_TRACE */
1878
1879#ifdef CONFIG_EVENT_TRACING
1880
1881void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
1882{
1883 int i = 0;
1884
1885 if (op & REQ_PREFLUSH)
1886 rwbs[i++] = 'F';
1887
1888 switch (op & REQ_OP_MASK) {
1889 case REQ_OP_WRITE:
1890 case REQ_OP_WRITE_SAME:
1891 rwbs[i++] = 'W';
1892 break;
1893 case REQ_OP_DISCARD:
1894 rwbs[i++] = 'D';
1895 break;
1896 case REQ_OP_SECURE_ERASE:
1897 rwbs[i++] = 'D';
1898 rwbs[i++] = 'E';
1899 break;
1900 case REQ_OP_FLUSH:
1901 rwbs[i++] = 'F';
1902 break;
1903 case REQ_OP_READ:
1904 rwbs[i++] = 'R';
1905 break;
1906 default:
1907 rwbs[i++] = 'N';
1908 }
1909
1910 if (op & REQ_FUA)
1911 rwbs[i++] = 'F';
1912 if (op & REQ_RAHEAD)
1913 rwbs[i++] = 'A';
1914 if (op & REQ_SYNC)
1915 rwbs[i++] = 'S';
1916 if (op & REQ_META)
1917 rwbs[i++] = 'M';
1918
1919 rwbs[i] = '\0';
1920}
1921EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1922
1923#endif /* CONFIG_EVENT_TRACING */
1924
1925