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Merge tag 'trace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...
[mirror_ubuntu-jammy-kernel.git] / kernel / trace / blktrace.c
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
31 static unsigned int blktrace_seq __read_mostly = 1;
32
33 static struct trace_array *blk_tr;
34 static bool blk_tracer_enabled __read_mostly;
35
36 static LIST_HEAD(running_trace_list);
37 static __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
44 static 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
54 static struct tracer_flags blk_tracer_flags = {
55 .val = 0,
56 .opts = blk_tracer_opts,
57 };
58
59 /* Global reference count of probes */
60 static DEFINE_MUTEX(blk_probe_mutex);
61 static int blk_probes_ref;
62
63 static void blk_register_tracepoints(void);
64 static void blk_unregister_tracepoints(void);
65
66 /*
67 * Send out a notify message.
68 */
69 static 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 int pc = 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 pc = preempt_count();
83 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
84 sizeof(*t) + len + cgid_len,
85 0, pc);
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());
99 record_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, 0, pc);
111 }
112 }
113
114 /*
115 * Send out a notify for this process, if we haven't done so since a trace
116 * started
117 */
118 static 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
132 static 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
148 void __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 }
183 EXPORT_SYMBOL_GPL(__trace_note_message);
184
185 static 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 */
201 static 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 */
215 static 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 pid_t pid;
226 int cpu, pc = 0;
227 bool blk_tracer = blk_tracer_enabled;
228 ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
229
230 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
231 return;
232
233 what |= ddir_act[op_is_write(op) ? WRITE : READ];
234 what |= MASK_TC_BIT(op_flags, SYNC);
235 what |= MASK_TC_BIT(op_flags, RAHEAD);
236 what |= MASK_TC_BIT(op_flags, META);
237 what |= MASK_TC_BIT(op_flags, PREFLUSH);
238 what |= MASK_TC_BIT(op_flags, FUA);
239 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
240 what |= BLK_TC_ACT(BLK_TC_DISCARD);
241 if (op == REQ_OP_FLUSH)
242 what |= BLK_TC_ACT(BLK_TC_FLUSH);
243 if (cgid)
244 what |= __BLK_TA_CGROUP;
245
246 pid = tsk->pid;
247 if (act_log_check(bt, what, sector, pid))
248 return;
249 cpu = raw_smp_processor_id();
250
251 if (blk_tracer) {
252 tracing_record_cmdline(current);
253
254 buffer = blk_tr->array_buffer.buffer;
255 pc = preempt_count();
256 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
257 sizeof(*t) + pdu_len + cgid_len,
258 0, pc);
259 if (!event)
260 return;
261 t = ring_buffer_event_data(event);
262 goto record_it;
263 }
264
265 if (unlikely(tsk->btrace_seq != blktrace_seq))
266 trace_note_tsk(tsk);
267
268 /*
269 * A word about the locking here - we disable interrupts to reserve
270 * some space in the relay per-cpu buffer, to prevent an irq
271 * from coming in and stepping on our toes.
272 */
273 local_irq_save(flags);
274 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
275 if (t) {
276 sequence = per_cpu_ptr(bt->sequence, cpu);
277
278 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
279 t->sequence = ++(*sequence);
280 t->time = ktime_to_ns(ktime_get());
281 record_it:
282 /*
283 * These two are not needed in ftrace as they are in the
284 * generic trace_entry, filled by tracing_generic_entry_update,
285 * but for the trace_event->bin() synthesizer benefit we do it
286 * here too.
287 */
288 t->cpu = cpu;
289 t->pid = pid;
290
291 t->sector = sector;
292 t->bytes = bytes;
293 t->action = what;
294 t->device = bt->dev;
295 t->error = error;
296 t->pdu_len = pdu_len + cgid_len;
297
298 if (cgid_len)
299 memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
300 if (pdu_len)
301 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
302
303 if (blk_tracer) {
304 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
305 return;
306 }
307 }
308
309 local_irq_restore(flags);
310 }
311
312 static void blk_trace_free(struct blk_trace *bt)
313 {
314 debugfs_remove(bt->msg_file);
315 debugfs_remove(bt->dropped_file);
316 relay_close(bt->rchan);
317 debugfs_remove(bt->dir);
318 free_percpu(bt->sequence);
319 free_percpu(bt->msg_data);
320 kfree(bt);
321 }
322
323 static void get_probe_ref(void)
324 {
325 mutex_lock(&blk_probe_mutex);
326 if (++blk_probes_ref == 1)
327 blk_register_tracepoints();
328 mutex_unlock(&blk_probe_mutex);
329 }
330
331 static void put_probe_ref(void)
332 {
333 mutex_lock(&blk_probe_mutex);
334 if (!--blk_probes_ref)
335 blk_unregister_tracepoints();
336 mutex_unlock(&blk_probe_mutex);
337 }
338
339 static void blk_trace_cleanup(struct blk_trace *bt)
340 {
341 synchronize_rcu();
342 blk_trace_free(bt);
343 put_probe_ref();
344 }
345
346 static int __blk_trace_remove(struct request_queue *q)
347 {
348 struct blk_trace *bt;
349
350 bt = rcu_replace_pointer(q->blk_trace, NULL,
351 lockdep_is_held(&q->debugfs_mutex));
352 if (!bt)
353 return -EINVAL;
354
355 if (bt->trace_state != Blktrace_running)
356 blk_trace_cleanup(bt);
357
358 return 0;
359 }
360
361 int blk_trace_remove(struct request_queue *q)
362 {
363 int ret;
364
365 mutex_lock(&q->debugfs_mutex);
366 ret = __blk_trace_remove(q);
367 mutex_unlock(&q->debugfs_mutex);
368
369 return ret;
370 }
371 EXPORT_SYMBOL_GPL(blk_trace_remove);
372
373 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
374 size_t count, loff_t *ppos)
375 {
376 struct blk_trace *bt = filp->private_data;
377 char buf[16];
378
379 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
380
381 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
382 }
383
384 static const struct file_operations blk_dropped_fops = {
385 .owner = THIS_MODULE,
386 .open = simple_open,
387 .read = blk_dropped_read,
388 .llseek = default_llseek,
389 };
390
391 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
392 size_t count, loff_t *ppos)
393 {
394 char *msg;
395 struct blk_trace *bt;
396
397 if (count >= BLK_TN_MAX_MSG)
398 return -EINVAL;
399
400 msg = memdup_user_nul(buffer, count);
401 if (IS_ERR(msg))
402 return PTR_ERR(msg);
403
404 bt = filp->private_data;
405 __trace_note_message(bt, NULL, "%s", msg);
406 kfree(msg);
407
408 return count;
409 }
410
411 static const struct file_operations blk_msg_fops = {
412 .owner = THIS_MODULE,
413 .open = simple_open,
414 .write = blk_msg_write,
415 .llseek = noop_llseek,
416 };
417
418 /*
419 * Keep track of how many times we encountered a full subbuffer, to aid
420 * the user space app in telling how many lost events there were.
421 */
422 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
423 void *prev_subbuf, size_t prev_padding)
424 {
425 struct blk_trace *bt;
426
427 if (!relay_buf_full(buf))
428 return 1;
429
430 bt = buf->chan->private_data;
431 atomic_inc(&bt->dropped);
432 return 0;
433 }
434
435 static int blk_remove_buf_file_callback(struct dentry *dentry)
436 {
437 debugfs_remove(dentry);
438
439 return 0;
440 }
441
442 static struct dentry *blk_create_buf_file_callback(const char *filename,
443 struct dentry *parent,
444 umode_t mode,
445 struct rchan_buf *buf,
446 int *is_global)
447 {
448 return debugfs_create_file(filename, mode, parent, buf,
449 &relay_file_operations);
450 }
451
452 static const struct rchan_callbacks blk_relay_callbacks = {
453 .subbuf_start = blk_subbuf_start_callback,
454 .create_buf_file = blk_create_buf_file_callback,
455 .remove_buf_file = blk_remove_buf_file_callback,
456 };
457
458 static void blk_trace_setup_lba(struct blk_trace *bt,
459 struct block_device *bdev)
460 {
461 if (bdev) {
462 bt->start_lba = bdev->bd_start_sect;
463 bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev);
464 } else {
465 bt->start_lba = 0;
466 bt->end_lba = -1ULL;
467 }
468 }
469
470 /*
471 * Setup everything required to start tracing
472 */
473 static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
474 struct block_device *bdev,
475 struct blk_user_trace_setup *buts)
476 {
477 struct blk_trace *bt = NULL;
478 struct dentry *dir = NULL;
479 int ret;
480
481 lockdep_assert_held(&q->debugfs_mutex);
482
483 if (!buts->buf_size || !buts->buf_nr)
484 return -EINVAL;
485
486 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
487 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
488
489 /*
490 * some device names have larger paths - convert the slashes
491 * to underscores for this to work as expected
492 */
493 strreplace(buts->name, '/', '_');
494
495 /*
496 * bdev can be NULL, as with scsi-generic, this is a helpful as
497 * we can be.
498 */
499 if (rcu_dereference_protected(q->blk_trace,
500 lockdep_is_held(&q->debugfs_mutex))) {
501 pr_warn("Concurrent blktraces are not allowed on %s\n",
502 buts->name);
503 return -EBUSY;
504 }
505
506 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
507 if (!bt)
508 return -ENOMEM;
509
510 ret = -ENOMEM;
511 bt->sequence = alloc_percpu(unsigned long);
512 if (!bt->sequence)
513 goto err;
514
515 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
516 if (!bt->msg_data)
517 goto err;
518
519 /*
520 * When tracing the whole disk reuse the existing debugfs directory
521 * created by the block layer on init. For partitions block devices,
522 * and scsi-generic block devices we create a temporary new debugfs
523 * directory that will be removed once the trace ends.
524 */
525 if (bdev && !bdev_is_partition(bdev))
526 dir = q->debugfs_dir;
527 else
528 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
529
530 /*
531 * As blktrace relies on debugfs for its interface the debugfs directory
532 * is required, contrary to the usual mantra of not checking for debugfs
533 * files or directories.
534 */
535 if (IS_ERR_OR_NULL(dir)) {
536 pr_warn("debugfs_dir not present for %s so skipping\n",
537 buts->name);
538 ret = -ENOENT;
539 goto err;
540 }
541
542 bt->dev = dev;
543 atomic_set(&bt->dropped, 0);
544 INIT_LIST_HEAD(&bt->running_list);
545
546 ret = -EIO;
547 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
548 &blk_dropped_fops);
549
550 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
551
552 bt->rchan = relay_open("trace", dir, buts->buf_size,
553 buts->buf_nr, &blk_relay_callbacks, bt);
554 if (!bt->rchan)
555 goto err;
556
557 bt->act_mask = buts->act_mask;
558 if (!bt->act_mask)
559 bt->act_mask = (u16) -1;
560
561 blk_trace_setup_lba(bt, bdev);
562
563 /* overwrite with user settings */
564 if (buts->start_lba)
565 bt->start_lba = buts->start_lba;
566 if (buts->end_lba)
567 bt->end_lba = buts->end_lba;
568
569 bt->pid = buts->pid;
570 bt->trace_state = Blktrace_setup;
571
572 rcu_assign_pointer(q->blk_trace, bt);
573 get_probe_ref();
574
575 ret = 0;
576 err:
577 if (ret)
578 blk_trace_free(bt);
579 return ret;
580 }
581
582 static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
583 struct block_device *bdev, char __user *arg)
584 {
585 struct blk_user_trace_setup buts;
586 int ret;
587
588 ret = copy_from_user(&buts, arg, sizeof(buts));
589 if (ret)
590 return -EFAULT;
591
592 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
593 if (ret)
594 return ret;
595
596 if (copy_to_user(arg, &buts, sizeof(buts))) {
597 __blk_trace_remove(q);
598 return -EFAULT;
599 }
600 return 0;
601 }
602
603 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
604 struct block_device *bdev,
605 char __user *arg)
606 {
607 int ret;
608
609 mutex_lock(&q->debugfs_mutex);
610 ret = __blk_trace_setup(q, name, dev, bdev, arg);
611 mutex_unlock(&q->debugfs_mutex);
612
613 return ret;
614 }
615 EXPORT_SYMBOL_GPL(blk_trace_setup);
616
617 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
618 static int compat_blk_trace_setup(struct request_queue *q, char *name,
619 dev_t dev, struct block_device *bdev,
620 char __user *arg)
621 {
622 struct blk_user_trace_setup buts;
623 struct compat_blk_user_trace_setup cbuts;
624 int ret;
625
626 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
627 return -EFAULT;
628
629 buts = (struct blk_user_trace_setup) {
630 .act_mask = cbuts.act_mask,
631 .buf_size = cbuts.buf_size,
632 .buf_nr = cbuts.buf_nr,
633 .start_lba = cbuts.start_lba,
634 .end_lba = cbuts.end_lba,
635 .pid = cbuts.pid,
636 };
637
638 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
639 if (ret)
640 return ret;
641
642 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
643 __blk_trace_remove(q);
644 return -EFAULT;
645 }
646
647 return 0;
648 }
649 #endif
650
651 static int __blk_trace_startstop(struct request_queue *q, int start)
652 {
653 int ret;
654 struct blk_trace *bt;
655
656 bt = rcu_dereference_protected(q->blk_trace,
657 lockdep_is_held(&q->debugfs_mutex));
658 if (bt == NULL)
659 return -EINVAL;
660
661 /*
662 * For starting a trace, we can transition from a setup or stopped
663 * trace. For stopping a trace, the state must be running
664 */
665 ret = -EINVAL;
666 if (start) {
667 if (bt->trace_state == Blktrace_setup ||
668 bt->trace_state == Blktrace_stopped) {
669 blktrace_seq++;
670 smp_mb();
671 bt->trace_state = Blktrace_running;
672 spin_lock_irq(&running_trace_lock);
673 list_add(&bt->running_list, &running_trace_list);
674 spin_unlock_irq(&running_trace_lock);
675
676 trace_note_time(bt);
677 ret = 0;
678 }
679 } else {
680 if (bt->trace_state == Blktrace_running) {
681 bt->trace_state = Blktrace_stopped;
682 spin_lock_irq(&running_trace_lock);
683 list_del_init(&bt->running_list);
684 spin_unlock_irq(&running_trace_lock);
685 relay_flush(bt->rchan);
686 ret = 0;
687 }
688 }
689
690 return ret;
691 }
692
693 int blk_trace_startstop(struct request_queue *q, int start)
694 {
695 int ret;
696
697 mutex_lock(&q->debugfs_mutex);
698 ret = __blk_trace_startstop(q, start);
699 mutex_unlock(&q->debugfs_mutex);
700
701 return ret;
702 }
703 EXPORT_SYMBOL_GPL(blk_trace_startstop);
704
705 /*
706 * When reading or writing the blktrace sysfs files, the references to the
707 * opened sysfs or device files should prevent the underlying block device
708 * from being removed. So no further delete protection is really needed.
709 */
710
711 /**
712 * blk_trace_ioctl: - handle the ioctls associated with tracing
713 * @bdev: the block device
714 * @cmd: the ioctl cmd
715 * @arg: the argument data, if any
716 *
717 **/
718 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
719 {
720 struct request_queue *q;
721 int ret, start = 0;
722 char b[BDEVNAME_SIZE];
723
724 q = bdev_get_queue(bdev);
725 if (!q)
726 return -ENXIO;
727
728 mutex_lock(&q->debugfs_mutex);
729
730 switch (cmd) {
731 case BLKTRACESETUP:
732 bdevname(bdev, b);
733 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
734 break;
735 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
736 case BLKTRACESETUP32:
737 bdevname(bdev, b);
738 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
739 break;
740 #endif
741 case BLKTRACESTART:
742 start = 1;
743 fallthrough;
744 case BLKTRACESTOP:
745 ret = __blk_trace_startstop(q, start);
746 break;
747 case BLKTRACETEARDOWN:
748 ret = __blk_trace_remove(q);
749 break;
750 default:
751 ret = -ENOTTY;
752 break;
753 }
754
755 mutex_unlock(&q->debugfs_mutex);
756 return ret;
757 }
758
759 /**
760 * blk_trace_shutdown: - stop and cleanup trace structures
761 * @q: the request queue associated with the device
762 *
763 **/
764 void blk_trace_shutdown(struct request_queue *q)
765 {
766 mutex_lock(&q->debugfs_mutex);
767 if (rcu_dereference_protected(q->blk_trace,
768 lockdep_is_held(&q->debugfs_mutex))) {
769 __blk_trace_startstop(q, 0);
770 __blk_trace_remove(q);
771 }
772
773 mutex_unlock(&q->debugfs_mutex);
774 }
775
776 #ifdef CONFIG_BLK_CGROUP
777 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
778 {
779 struct blk_trace *bt;
780
781 /* We don't use the 'bt' value here except as an optimization... */
782 bt = rcu_dereference_protected(q->blk_trace, 1);
783 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
784 return 0;
785
786 if (!bio->bi_blkg)
787 return 0;
788 return cgroup_id(bio_blkcg(bio)->css.cgroup);
789 }
790 #else
791 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
792 {
793 return 0;
794 }
795 #endif
796
797 static u64
798 blk_trace_request_get_cgid(struct request *rq)
799 {
800 if (!rq->bio)
801 return 0;
802 /* Use the first bio */
803 return blk_trace_bio_get_cgid(rq->q, rq->bio);
804 }
805
806 /*
807 * blktrace probes
808 */
809
810 /**
811 * blk_add_trace_rq - Add a trace for a request oriented action
812 * @rq: the source request
813 * @error: return status to log
814 * @nr_bytes: number of completed bytes
815 * @what: the action
816 * @cgid: the cgroup info
817 *
818 * Description:
819 * Records an action against a request. Will log the bio offset + size.
820 *
821 **/
822 static void blk_add_trace_rq(struct request *rq, int error,
823 unsigned int nr_bytes, u32 what, u64 cgid)
824 {
825 struct blk_trace *bt;
826
827 rcu_read_lock();
828 bt = rcu_dereference(rq->q->blk_trace);
829 if (likely(!bt)) {
830 rcu_read_unlock();
831 return;
832 }
833
834 if (blk_rq_is_passthrough(rq))
835 what |= BLK_TC_ACT(BLK_TC_PC);
836 else
837 what |= BLK_TC_ACT(BLK_TC_FS);
838
839 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
840 rq->cmd_flags, what, error, 0, NULL, cgid);
841 rcu_read_unlock();
842 }
843
844 static void blk_add_trace_rq_insert(void *ignore, struct request *rq)
845 {
846 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
847 blk_trace_request_get_cgid(rq));
848 }
849
850 static void blk_add_trace_rq_issue(void *ignore, struct request *rq)
851 {
852 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
853 blk_trace_request_get_cgid(rq));
854 }
855
856 static void blk_add_trace_rq_merge(void *ignore, struct request *rq)
857 {
858 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
859 blk_trace_request_get_cgid(rq));
860 }
861
862 static void blk_add_trace_rq_requeue(void *ignore, struct request *rq)
863 {
864 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
865 blk_trace_request_get_cgid(rq));
866 }
867
868 static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
869 int error, unsigned int nr_bytes)
870 {
871 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
872 blk_trace_request_get_cgid(rq));
873 }
874
875 /**
876 * blk_add_trace_bio - Add a trace for a bio oriented action
877 * @q: queue the io is for
878 * @bio: the source bio
879 * @what: the action
880 * @error: error, if any
881 *
882 * Description:
883 * Records an action against a bio. Will log the bio offset + size.
884 *
885 **/
886 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
887 u32 what, int error)
888 {
889 struct blk_trace *bt;
890
891 rcu_read_lock();
892 bt = rcu_dereference(q->blk_trace);
893 if (likely(!bt)) {
894 rcu_read_unlock();
895 return;
896 }
897
898 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
899 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
900 blk_trace_bio_get_cgid(q, bio));
901 rcu_read_unlock();
902 }
903
904 static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio)
905 {
906 blk_add_trace_bio(bio->bi_disk->queue, bio, BLK_TA_BOUNCE, 0);
907 }
908
909 static void blk_add_trace_bio_complete(void *ignore,
910 struct request_queue *q, struct bio *bio)
911 {
912 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
913 blk_status_to_errno(bio->bi_status));
914 }
915
916 static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio)
917 {
918 blk_add_trace_bio(bio->bi_disk->queue, bio, BLK_TA_BACKMERGE, 0);
919 }
920
921 static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio)
922 {
923 blk_add_trace_bio(bio->bi_disk->queue, bio, BLK_TA_FRONTMERGE, 0);
924 }
925
926 static void blk_add_trace_bio_queue(void *ignore, struct bio *bio)
927 {
928 blk_add_trace_bio(bio->bi_disk->queue, bio, BLK_TA_QUEUE, 0);
929 }
930
931 static void blk_add_trace_getrq(void *ignore, struct bio *bio)
932 {
933 blk_add_trace_bio(bio->bi_disk->queue, bio, BLK_TA_GETRQ, 0);
934 }
935
936 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
937 {
938 struct blk_trace *bt;
939
940 rcu_read_lock();
941 bt = rcu_dereference(q->blk_trace);
942 if (bt)
943 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
944 rcu_read_unlock();
945 }
946
947 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
948 unsigned int depth, bool explicit)
949 {
950 struct blk_trace *bt;
951
952 rcu_read_lock();
953 bt = rcu_dereference(q->blk_trace);
954 if (bt) {
955 __be64 rpdu = cpu_to_be64(depth);
956 u32 what;
957
958 if (explicit)
959 what = BLK_TA_UNPLUG_IO;
960 else
961 what = BLK_TA_UNPLUG_TIMER;
962
963 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
964 }
965 rcu_read_unlock();
966 }
967
968 static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
969 {
970 struct request_queue *q = bio->bi_disk->queue;
971 struct blk_trace *bt;
972
973 rcu_read_lock();
974 bt = rcu_dereference(q->blk_trace);
975 if (bt) {
976 __be64 rpdu = cpu_to_be64(pdu);
977
978 __blk_add_trace(bt, bio->bi_iter.bi_sector,
979 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
980 BLK_TA_SPLIT,
981 blk_status_to_errno(bio->bi_status),
982 sizeof(rpdu), &rpdu,
983 blk_trace_bio_get_cgid(q, bio));
984 }
985 rcu_read_unlock();
986 }
987
988 /**
989 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
990 * @ignore: trace callback data parameter (not used)
991 * @bio: the source bio
992 * @dev: source device
993 * @from: source sector
994 *
995 * Called after a bio is remapped to a different device and/or sector.
996 **/
997 static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev,
998 sector_t from)
999 {
1000 struct request_queue *q = bio->bi_disk->queue;
1001 struct blk_trace *bt;
1002 struct blk_io_trace_remap r;
1003
1004 rcu_read_lock();
1005 bt = rcu_dereference(q->blk_trace);
1006 if (likely(!bt)) {
1007 rcu_read_unlock();
1008 return;
1009 }
1010
1011 r.device_from = cpu_to_be32(dev);
1012 r.device_to = cpu_to_be32(bio_dev(bio));
1013 r.sector_from = cpu_to_be64(from);
1014
1015 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1016 bio_op(bio), bio->bi_opf, BLK_TA_REMAP,
1017 blk_status_to_errno(bio->bi_status),
1018 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1019 rcu_read_unlock();
1020 }
1021
1022 /**
1023 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1024 * @ignore: trace callback data parameter (not used)
1025 * @rq: the source request
1026 * @dev: target device
1027 * @from: source sector
1028 *
1029 * Description:
1030 * Device mapper remaps request to other devices.
1031 * Add a trace for that action.
1032 *
1033 **/
1034 static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev,
1035 sector_t from)
1036 {
1037 struct blk_trace *bt;
1038 struct blk_io_trace_remap r;
1039
1040 rcu_read_lock();
1041 bt = rcu_dereference(rq->q->blk_trace);
1042 if (likely(!bt)) {
1043 rcu_read_unlock();
1044 return;
1045 }
1046
1047 r.device_from = cpu_to_be32(dev);
1048 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1049 r.sector_from = cpu_to_be64(from);
1050
1051 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1052 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1053 sizeof(r), &r, blk_trace_request_get_cgid(rq));
1054 rcu_read_unlock();
1055 }
1056
1057 /**
1058 * blk_add_driver_data - Add binary message with driver-specific data
1059 * @rq: io request
1060 * @data: driver-specific data
1061 * @len: length of driver-specific data
1062 *
1063 * Description:
1064 * Some drivers might want to write driver-specific data per request.
1065 *
1066 **/
1067 void blk_add_driver_data(struct request *rq, void *data, size_t len)
1068 {
1069 struct blk_trace *bt;
1070
1071 rcu_read_lock();
1072 bt = rcu_dereference(rq->q->blk_trace);
1073 if (likely(!bt)) {
1074 rcu_read_unlock();
1075 return;
1076 }
1077
1078 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1079 BLK_TA_DRV_DATA, 0, len, data,
1080 blk_trace_request_get_cgid(rq));
1081 rcu_read_unlock();
1082 }
1083 EXPORT_SYMBOL_GPL(blk_add_driver_data);
1084
1085 static void blk_register_tracepoints(void)
1086 {
1087 int ret;
1088
1089 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1090 WARN_ON(ret);
1091 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1092 WARN_ON(ret);
1093 ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1094 WARN_ON(ret);
1095 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1096 WARN_ON(ret);
1097 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1098 WARN_ON(ret);
1099 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1100 WARN_ON(ret);
1101 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1102 WARN_ON(ret);
1103 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1104 WARN_ON(ret);
1105 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1106 WARN_ON(ret);
1107 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1108 WARN_ON(ret);
1109 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1110 WARN_ON(ret);
1111 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1112 WARN_ON(ret);
1113 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1114 WARN_ON(ret);
1115 ret = register_trace_block_split(blk_add_trace_split, NULL);
1116 WARN_ON(ret);
1117 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1118 WARN_ON(ret);
1119 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1120 WARN_ON(ret);
1121 }
1122
1123 static void blk_unregister_tracepoints(void)
1124 {
1125 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1126 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1127 unregister_trace_block_split(blk_add_trace_split, NULL);
1128 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1129 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1130 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1131 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1132 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1133 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1134 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1135 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1136 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1137 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1138 unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1139 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1140 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1141
1142 tracepoint_synchronize_unregister();
1143 }
1144
1145 /*
1146 * struct blk_io_tracer formatting routines
1147 */
1148
1149 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1150 {
1151 int i = 0;
1152 int tc = t->action >> BLK_TC_SHIFT;
1153
1154 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1155 rwbs[i++] = 'N';
1156 goto out;
1157 }
1158
1159 if (tc & BLK_TC_FLUSH)
1160 rwbs[i++] = 'F';
1161
1162 if (tc & BLK_TC_DISCARD)
1163 rwbs[i++] = 'D';
1164 else if (tc & BLK_TC_WRITE)
1165 rwbs[i++] = 'W';
1166 else if (t->bytes)
1167 rwbs[i++] = 'R';
1168 else
1169 rwbs[i++] = 'N';
1170
1171 if (tc & BLK_TC_FUA)
1172 rwbs[i++] = 'F';
1173 if (tc & BLK_TC_AHEAD)
1174 rwbs[i++] = 'A';
1175 if (tc & BLK_TC_SYNC)
1176 rwbs[i++] = 'S';
1177 if (tc & BLK_TC_META)
1178 rwbs[i++] = 'M';
1179 out:
1180 rwbs[i] = '\0';
1181 }
1182
1183 static inline
1184 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1185 {
1186 return (const struct blk_io_trace *)ent;
1187 }
1188
1189 static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1190 {
1191 return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
1192 }
1193
1194 static inline u64 t_cgid(const struct trace_entry *ent)
1195 {
1196 return *(u64 *)(te_blk_io_trace(ent) + 1);
1197 }
1198
1199 static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1200 {
1201 return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
1202 }
1203
1204 static inline u32 t_action(const struct trace_entry *ent)
1205 {
1206 return te_blk_io_trace(ent)->action;
1207 }
1208
1209 static inline u32 t_bytes(const struct trace_entry *ent)
1210 {
1211 return te_blk_io_trace(ent)->bytes;
1212 }
1213
1214 static inline u32 t_sec(const struct trace_entry *ent)
1215 {
1216 return te_blk_io_trace(ent)->bytes >> 9;
1217 }
1218
1219 static inline unsigned long long t_sector(const struct trace_entry *ent)
1220 {
1221 return te_blk_io_trace(ent)->sector;
1222 }
1223
1224 static inline __u16 t_error(const struct trace_entry *ent)
1225 {
1226 return te_blk_io_trace(ent)->error;
1227 }
1228
1229 static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1230 {
1231 const __be64 *val = pdu_start(ent, has_cg);
1232 return be64_to_cpu(*val);
1233 }
1234
1235 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1236 bool has_cg);
1237
1238 static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1239 bool has_cg)
1240 {
1241 char rwbs[RWBS_LEN];
1242 unsigned long long ts = iter->ts;
1243 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1244 unsigned secs = (unsigned long)ts;
1245 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1246
1247 fill_rwbs(rwbs, t);
1248
1249 trace_seq_printf(&iter->seq,
1250 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1251 MAJOR(t->device), MINOR(t->device), iter->cpu,
1252 secs, nsec_rem, iter->ent->pid, act, rwbs);
1253 }
1254
1255 static void blk_log_action(struct trace_iterator *iter, const char *act,
1256 bool has_cg)
1257 {
1258 char rwbs[RWBS_LEN];
1259 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1260
1261 fill_rwbs(rwbs, t);
1262 if (has_cg) {
1263 u64 id = t_cgid(iter->ent);
1264
1265 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1266 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1267
1268 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1269 sizeof(blkcg_name_buf));
1270 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1271 MAJOR(t->device), MINOR(t->device),
1272 blkcg_name_buf, act, rwbs);
1273 } else {
1274 /*
1275 * The cgid portion used to be "INO,GEN". Userland
1276 * builds a FILEID_INO32_GEN fid out of them and
1277 * opens the cgroup using open_by_handle_at(2).
1278 * While 32bit ino setups are still the same, 64bit
1279 * ones now use the 64bit ino as the whole ID and
1280 * no longer use generation.
1281 *
1282 * Regardless of the content, always output
1283 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
1284 * be mapped back to @id on both 64 and 32bit ino
1285 * setups. See __kernfs_fh_to_dentry().
1286 */
1287 trace_seq_printf(&iter->seq,
1288 "%3d,%-3d %llx,%-llx %2s %3s ",
1289 MAJOR(t->device), MINOR(t->device),
1290 id & U32_MAX, id >> 32, act, rwbs);
1291 }
1292 } else
1293 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1294 MAJOR(t->device), MINOR(t->device), act, rwbs);
1295 }
1296
1297 static void blk_log_dump_pdu(struct trace_seq *s,
1298 const struct trace_entry *ent, bool has_cg)
1299 {
1300 const unsigned char *pdu_buf;
1301 int pdu_len;
1302 int i, end;
1303
1304 pdu_buf = pdu_start(ent, has_cg);
1305 pdu_len = pdu_real_len(ent, has_cg);
1306
1307 if (!pdu_len)
1308 return;
1309
1310 /* find the last zero that needs to be printed */
1311 for (end = pdu_len - 1; end >= 0; end--)
1312 if (pdu_buf[end])
1313 break;
1314 end++;
1315
1316 trace_seq_putc(s, '(');
1317
1318 for (i = 0; i < pdu_len; i++) {
1319
1320 trace_seq_printf(s, "%s%02x",
1321 i == 0 ? "" : " ", pdu_buf[i]);
1322
1323 /*
1324 * stop when the rest is just zeros and indicate so
1325 * with a ".." appended
1326 */
1327 if (i == end && end != pdu_len - 1) {
1328 trace_seq_puts(s, " ..) ");
1329 return;
1330 }
1331 }
1332
1333 trace_seq_puts(s, ") ");
1334 }
1335
1336 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1337 {
1338 char cmd[TASK_COMM_LEN];
1339
1340 trace_find_cmdline(ent->pid, cmd);
1341
1342 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1343 trace_seq_printf(s, "%u ", t_bytes(ent));
1344 blk_log_dump_pdu(s, ent, has_cg);
1345 trace_seq_printf(s, "[%s]\n", cmd);
1346 } else {
1347 if (t_sec(ent))
1348 trace_seq_printf(s, "%llu + %u [%s]\n",
1349 t_sector(ent), t_sec(ent), cmd);
1350 else
1351 trace_seq_printf(s, "[%s]\n", cmd);
1352 }
1353 }
1354
1355 static void blk_log_with_error(struct trace_seq *s,
1356 const struct trace_entry *ent, bool has_cg)
1357 {
1358 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1359 blk_log_dump_pdu(s, ent, has_cg);
1360 trace_seq_printf(s, "[%d]\n", t_error(ent));
1361 } else {
1362 if (t_sec(ent))
1363 trace_seq_printf(s, "%llu + %u [%d]\n",
1364 t_sector(ent),
1365 t_sec(ent), t_error(ent));
1366 else
1367 trace_seq_printf(s, "%llu [%d]\n",
1368 t_sector(ent), t_error(ent));
1369 }
1370 }
1371
1372 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1373 {
1374 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1375
1376 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1377 t_sector(ent), t_sec(ent),
1378 MAJOR(be32_to_cpu(__r->device_from)),
1379 MINOR(be32_to_cpu(__r->device_from)),
1380 be64_to_cpu(__r->sector_from));
1381 }
1382
1383 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1384 {
1385 char cmd[TASK_COMM_LEN];
1386
1387 trace_find_cmdline(ent->pid, cmd);
1388
1389 trace_seq_printf(s, "[%s]\n", cmd);
1390 }
1391
1392 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1393 {
1394 char cmd[TASK_COMM_LEN];
1395
1396 trace_find_cmdline(ent->pid, cmd);
1397
1398 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1399 }
1400
1401 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1402 {
1403 char cmd[TASK_COMM_LEN];
1404
1405 trace_find_cmdline(ent->pid, cmd);
1406
1407 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1408 get_pdu_int(ent, has_cg), cmd);
1409 }
1410
1411 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1412 bool has_cg)
1413 {
1414
1415 trace_seq_putmem(s, pdu_start(ent, has_cg),
1416 pdu_real_len(ent, has_cg));
1417 trace_seq_putc(s, '\n');
1418 }
1419
1420 /*
1421 * struct tracer operations
1422 */
1423
1424 static void blk_tracer_print_header(struct seq_file *m)
1425 {
1426 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1427 return;
1428 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1429 "# | | | | | |\n");
1430 }
1431
1432 static void blk_tracer_start(struct trace_array *tr)
1433 {
1434 blk_tracer_enabled = true;
1435 }
1436
1437 static int blk_tracer_init(struct trace_array *tr)
1438 {
1439 blk_tr = tr;
1440 blk_tracer_start(tr);
1441 return 0;
1442 }
1443
1444 static void blk_tracer_stop(struct trace_array *tr)
1445 {
1446 blk_tracer_enabled = false;
1447 }
1448
1449 static void blk_tracer_reset(struct trace_array *tr)
1450 {
1451 blk_tracer_stop(tr);
1452 }
1453
1454 static const struct {
1455 const char *act[2];
1456 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1457 bool has_cg);
1458 } what2act[] = {
1459 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1460 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1461 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1462 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1463 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1464 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1465 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1466 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1467 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1468 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1469 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1470 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1471 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1472 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1473 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1474 };
1475
1476 static enum print_line_t print_one_line(struct trace_iterator *iter,
1477 bool classic)
1478 {
1479 struct trace_array *tr = iter->tr;
1480 struct trace_seq *s = &iter->seq;
1481 const struct blk_io_trace *t;
1482 u16 what;
1483 bool long_act;
1484 blk_log_action_t *log_action;
1485 bool has_cg;
1486
1487 t = te_blk_io_trace(iter->ent);
1488 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1489 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1490 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1491 has_cg = t->action & __BLK_TA_CGROUP;
1492
1493 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1494 log_action(iter, long_act ? "message" : "m", has_cg);
1495 blk_log_msg(s, iter->ent, has_cg);
1496 return trace_handle_return(s);
1497 }
1498
1499 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1500 trace_seq_printf(s, "Unknown action %x\n", what);
1501 else {
1502 log_action(iter, what2act[what].act[long_act], has_cg);
1503 what2act[what].print(s, iter->ent, has_cg);
1504 }
1505
1506 return trace_handle_return(s);
1507 }
1508
1509 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1510 int flags, struct trace_event *event)
1511 {
1512 return print_one_line(iter, false);
1513 }
1514
1515 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1516 {
1517 struct trace_seq *s = &iter->seq;
1518 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1519 const int offset = offsetof(struct blk_io_trace, sector);
1520 struct blk_io_trace old = {
1521 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1522 .time = iter->ts,
1523 };
1524
1525 trace_seq_putmem(s, &old, offset);
1526 trace_seq_putmem(s, &t->sector,
1527 sizeof(old) - offset + t->pdu_len);
1528 }
1529
1530 static enum print_line_t
1531 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1532 struct trace_event *event)
1533 {
1534 blk_trace_synthesize_old_trace(iter);
1535
1536 return trace_handle_return(&iter->seq);
1537 }
1538
1539 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1540 {
1541 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1542 return TRACE_TYPE_UNHANDLED;
1543
1544 return print_one_line(iter, true);
1545 }
1546
1547 static int
1548 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1549 {
1550 /* don't output context-info for blk_classic output */
1551 if (bit == TRACE_BLK_OPT_CLASSIC) {
1552 if (set)
1553 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1554 else
1555 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1556 }
1557 return 0;
1558 }
1559
1560 static struct tracer blk_tracer __read_mostly = {
1561 .name = "blk",
1562 .init = blk_tracer_init,
1563 .reset = blk_tracer_reset,
1564 .start = blk_tracer_start,
1565 .stop = blk_tracer_stop,
1566 .print_header = blk_tracer_print_header,
1567 .print_line = blk_tracer_print_line,
1568 .flags = &blk_tracer_flags,
1569 .set_flag = blk_tracer_set_flag,
1570 };
1571
1572 static struct trace_event_functions trace_blk_event_funcs = {
1573 .trace = blk_trace_event_print,
1574 .binary = blk_trace_event_print_binary,
1575 };
1576
1577 static struct trace_event trace_blk_event = {
1578 .type = TRACE_BLK,
1579 .funcs = &trace_blk_event_funcs,
1580 };
1581
1582 static int __init init_blk_tracer(void)
1583 {
1584 if (!register_trace_event(&trace_blk_event)) {
1585 pr_warn("Warning: could not register block events\n");
1586 return 1;
1587 }
1588
1589 if (register_tracer(&blk_tracer) != 0) {
1590 pr_warn("Warning: could not register the block tracer\n");
1591 unregister_trace_event(&trace_blk_event);
1592 return 1;
1593 }
1594
1595 return 0;
1596 }
1597
1598 device_initcall(init_blk_tracer);
1599
1600 static int blk_trace_remove_queue(struct request_queue *q)
1601 {
1602 struct blk_trace *bt;
1603
1604 bt = rcu_replace_pointer(q->blk_trace, NULL,
1605 lockdep_is_held(&q->debugfs_mutex));
1606 if (bt == NULL)
1607 return -EINVAL;
1608
1609 put_probe_ref();
1610 synchronize_rcu();
1611 blk_trace_free(bt);
1612 return 0;
1613 }
1614
1615 /*
1616 * Setup everything required to start tracing
1617 */
1618 static int blk_trace_setup_queue(struct request_queue *q,
1619 struct block_device *bdev)
1620 {
1621 struct blk_trace *bt = NULL;
1622 int ret = -ENOMEM;
1623
1624 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1625 if (!bt)
1626 return -ENOMEM;
1627
1628 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1629 if (!bt->msg_data)
1630 goto free_bt;
1631
1632 bt->dev = bdev->bd_dev;
1633 bt->act_mask = (u16)-1;
1634
1635 blk_trace_setup_lba(bt, bdev);
1636
1637 rcu_assign_pointer(q->blk_trace, bt);
1638 get_probe_ref();
1639 return 0;
1640
1641 free_bt:
1642 blk_trace_free(bt);
1643 return ret;
1644 }
1645
1646 /*
1647 * sysfs interface to enable and configure tracing
1648 */
1649
1650 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1651 struct device_attribute *attr,
1652 char *buf);
1653 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1654 struct device_attribute *attr,
1655 const char *buf, size_t count);
1656 #define BLK_TRACE_DEVICE_ATTR(_name) \
1657 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1658 sysfs_blk_trace_attr_show, \
1659 sysfs_blk_trace_attr_store)
1660
1661 static BLK_TRACE_DEVICE_ATTR(enable);
1662 static BLK_TRACE_DEVICE_ATTR(act_mask);
1663 static BLK_TRACE_DEVICE_ATTR(pid);
1664 static BLK_TRACE_DEVICE_ATTR(start_lba);
1665 static BLK_TRACE_DEVICE_ATTR(end_lba);
1666
1667 static struct attribute *blk_trace_attrs[] = {
1668 &dev_attr_enable.attr,
1669 &dev_attr_act_mask.attr,
1670 &dev_attr_pid.attr,
1671 &dev_attr_start_lba.attr,
1672 &dev_attr_end_lba.attr,
1673 NULL
1674 };
1675
1676 struct attribute_group blk_trace_attr_group = {
1677 .name = "trace",
1678 .attrs = blk_trace_attrs,
1679 };
1680
1681 static const struct {
1682 int mask;
1683 const char *str;
1684 } mask_maps[] = {
1685 { BLK_TC_READ, "read" },
1686 { BLK_TC_WRITE, "write" },
1687 { BLK_TC_FLUSH, "flush" },
1688 { BLK_TC_SYNC, "sync" },
1689 { BLK_TC_QUEUE, "queue" },
1690 { BLK_TC_REQUEUE, "requeue" },
1691 { BLK_TC_ISSUE, "issue" },
1692 { BLK_TC_COMPLETE, "complete" },
1693 { BLK_TC_FS, "fs" },
1694 { BLK_TC_PC, "pc" },
1695 { BLK_TC_NOTIFY, "notify" },
1696 { BLK_TC_AHEAD, "ahead" },
1697 { BLK_TC_META, "meta" },
1698 { BLK_TC_DISCARD, "discard" },
1699 { BLK_TC_DRV_DATA, "drv_data" },
1700 { BLK_TC_FUA, "fua" },
1701 };
1702
1703 static int blk_trace_str2mask(const char *str)
1704 {
1705 int i;
1706 int mask = 0;
1707 char *buf, *s, *token;
1708
1709 buf = kstrdup(str, GFP_KERNEL);
1710 if (buf == NULL)
1711 return -ENOMEM;
1712 s = strstrip(buf);
1713
1714 while (1) {
1715 token = strsep(&s, ",");
1716 if (token == NULL)
1717 break;
1718
1719 if (*token == '\0')
1720 continue;
1721
1722 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1723 if (strcasecmp(token, mask_maps[i].str) == 0) {
1724 mask |= mask_maps[i].mask;
1725 break;
1726 }
1727 }
1728 if (i == ARRAY_SIZE(mask_maps)) {
1729 mask = -EINVAL;
1730 break;
1731 }
1732 }
1733 kfree(buf);
1734
1735 return mask;
1736 }
1737
1738 static ssize_t blk_trace_mask2str(char *buf, int mask)
1739 {
1740 int i;
1741 char *p = buf;
1742
1743 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1744 if (mask & mask_maps[i].mask) {
1745 p += sprintf(p, "%s%s",
1746 (p == buf) ? "" : ",", mask_maps[i].str);
1747 }
1748 }
1749 *p++ = '\n';
1750
1751 return p - buf;
1752 }
1753
1754 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1755 struct device_attribute *attr,
1756 char *buf)
1757 {
1758 struct block_device *bdev = dev_to_bdev(dev);
1759 struct request_queue *q = bdev_get_queue(bdev);
1760 struct blk_trace *bt;
1761 ssize_t ret = -ENXIO;
1762
1763 mutex_lock(&q->debugfs_mutex);
1764
1765 bt = rcu_dereference_protected(q->blk_trace,
1766 lockdep_is_held(&q->debugfs_mutex));
1767 if (attr == &dev_attr_enable) {
1768 ret = sprintf(buf, "%u\n", !!bt);
1769 goto out_unlock_bdev;
1770 }
1771
1772 if (bt == NULL)
1773 ret = sprintf(buf, "disabled\n");
1774 else if (attr == &dev_attr_act_mask)
1775 ret = blk_trace_mask2str(buf, bt->act_mask);
1776 else if (attr == &dev_attr_pid)
1777 ret = sprintf(buf, "%u\n", bt->pid);
1778 else if (attr == &dev_attr_start_lba)
1779 ret = sprintf(buf, "%llu\n", bt->start_lba);
1780 else if (attr == &dev_attr_end_lba)
1781 ret = sprintf(buf, "%llu\n", bt->end_lba);
1782
1783 out_unlock_bdev:
1784 mutex_unlock(&q->debugfs_mutex);
1785 return ret;
1786 }
1787
1788 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1789 struct device_attribute *attr,
1790 const char *buf, size_t count)
1791 {
1792 struct block_device *bdev = dev_to_bdev(dev);
1793 struct request_queue *q = bdev_get_queue(bdev);
1794 struct blk_trace *bt;
1795 u64 value;
1796 ssize_t ret = -EINVAL;
1797
1798 if (count == 0)
1799 goto out;
1800
1801 if (attr == &dev_attr_act_mask) {
1802 if (kstrtoull(buf, 0, &value)) {
1803 /* Assume it is a list of trace category names */
1804 ret = blk_trace_str2mask(buf);
1805 if (ret < 0)
1806 goto out;
1807 value = ret;
1808 }
1809 } else {
1810 if (kstrtoull(buf, 0, &value))
1811 goto out;
1812 }
1813
1814 mutex_lock(&q->debugfs_mutex);
1815
1816 bt = rcu_dereference_protected(q->blk_trace,
1817 lockdep_is_held(&q->debugfs_mutex));
1818 if (attr == &dev_attr_enable) {
1819 if (!!value == !!bt) {
1820 ret = 0;
1821 goto out_unlock_bdev;
1822 }
1823 if (value)
1824 ret = blk_trace_setup_queue(q, bdev);
1825 else
1826 ret = blk_trace_remove_queue(q);
1827 goto out_unlock_bdev;
1828 }
1829
1830 ret = 0;
1831 if (bt == NULL) {
1832 ret = blk_trace_setup_queue(q, bdev);
1833 bt = rcu_dereference_protected(q->blk_trace,
1834 lockdep_is_held(&q->debugfs_mutex));
1835 }
1836
1837 if (ret == 0) {
1838 if (attr == &dev_attr_act_mask)
1839 bt->act_mask = value;
1840 else if (attr == &dev_attr_pid)
1841 bt->pid = value;
1842 else if (attr == &dev_attr_start_lba)
1843 bt->start_lba = value;
1844 else if (attr == &dev_attr_end_lba)
1845 bt->end_lba = value;
1846 }
1847
1848 out_unlock_bdev:
1849 mutex_unlock(&q->debugfs_mutex);
1850 out:
1851 return ret ? ret : count;
1852 }
1853
1854 int blk_trace_init_sysfs(struct device *dev)
1855 {
1856 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1857 }
1858
1859 void blk_trace_remove_sysfs(struct device *dev)
1860 {
1861 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1862 }
1863
1864 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1865
1866 #ifdef CONFIG_EVENT_TRACING
1867
1868 void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
1869 {
1870 int i = 0;
1871
1872 if (op & REQ_PREFLUSH)
1873 rwbs[i++] = 'F';
1874
1875 switch (op & REQ_OP_MASK) {
1876 case REQ_OP_WRITE:
1877 case REQ_OP_WRITE_SAME:
1878 rwbs[i++] = 'W';
1879 break;
1880 case REQ_OP_DISCARD:
1881 rwbs[i++] = 'D';
1882 break;
1883 case REQ_OP_SECURE_ERASE:
1884 rwbs[i++] = 'D';
1885 rwbs[i++] = 'E';
1886 break;
1887 case REQ_OP_FLUSH:
1888 rwbs[i++] = 'F';
1889 break;
1890 case REQ_OP_READ:
1891 rwbs[i++] = 'R';
1892 break;
1893 default:
1894 rwbs[i++] = 'N';
1895 }
1896
1897 if (op & REQ_FUA)
1898 rwbs[i++] = 'F';
1899 if (op & REQ_RAHEAD)
1900 rwbs[i++] = 'A';
1901 if (op & REQ_SYNC)
1902 rwbs[i++] = 'S';
1903 if (op & REQ_META)
1904 rwbs[i++] = 'M';
1905
1906 rwbs[i] = '\0';
1907 }
1908 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1909
1910 #endif /* CONFIG_EVENT_TRACING */
1911
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