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Merge tag 'audit-pr-20201214' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoor...
[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 struct hd_struct *part = NULL;
462
463 if (bdev)
464 part = bdev->bd_part;
465
466 if (part) {
467 bt->start_lba = part->start_sect;
468 bt->end_lba = part->start_sect + part->nr_sects;
469 } else {
470 bt->start_lba = 0;
471 bt->end_lba = -1ULL;
472 }
473 }
474
475 /*
476 * Setup everything required to start tracing
477 */
478 static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
479 struct block_device *bdev,
480 struct blk_user_trace_setup *buts)
481 {
482 struct blk_trace *bt = NULL;
483 struct dentry *dir = NULL;
484 int ret;
485
486 lockdep_assert_held(&q->debugfs_mutex);
487
488 if (!buts->buf_size || !buts->buf_nr)
489 return -EINVAL;
490
491 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
492 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
493
494 /*
495 * some device names have larger paths - convert the slashes
496 * to underscores for this to work as expected
497 */
498 strreplace(buts->name, '/', '_');
499
500 /*
501 * bdev can be NULL, as with scsi-generic, this is a helpful as
502 * we can be.
503 */
504 if (rcu_dereference_protected(q->blk_trace,
505 lockdep_is_held(&q->debugfs_mutex))) {
506 pr_warn("Concurrent blktraces are not allowed on %s\n",
507 buts->name);
508 return -EBUSY;
509 }
510
511 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
512 if (!bt)
513 return -ENOMEM;
514
515 ret = -ENOMEM;
516 bt->sequence = alloc_percpu(unsigned long);
517 if (!bt->sequence)
518 goto err;
519
520 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
521 if (!bt->msg_data)
522 goto err;
523
524 /*
525 * When tracing the whole disk reuse the existing debugfs directory
526 * created by the block layer on init. For partitions block devices,
527 * and scsi-generic block devices we create a temporary new debugfs
528 * directory that will be removed once the trace ends.
529 */
530 if (bdev && !bdev_is_partition(bdev))
531 dir = q->debugfs_dir;
532 else
533 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
534
535 /*
536 * As blktrace relies on debugfs for its interface the debugfs directory
537 * is required, contrary to the usual mantra of not checking for debugfs
538 * files or directories.
539 */
540 if (IS_ERR_OR_NULL(dir)) {
541 pr_warn("debugfs_dir not present for %s so skipping\n",
542 buts->name);
543 ret = -ENOENT;
544 goto err;
545 }
546
547 bt->dev = dev;
548 atomic_set(&bt->dropped, 0);
549 INIT_LIST_HEAD(&bt->running_list);
550
551 ret = -EIO;
552 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
553 &blk_dropped_fops);
554
555 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
556
557 bt->rchan = relay_open("trace", dir, buts->buf_size,
558 buts->buf_nr, &blk_relay_callbacks, bt);
559 if (!bt->rchan)
560 goto err;
561
562 bt->act_mask = buts->act_mask;
563 if (!bt->act_mask)
564 bt->act_mask = (u16) -1;
565
566 blk_trace_setup_lba(bt, bdev);
567
568 /* overwrite with user settings */
569 if (buts->start_lba)
570 bt->start_lba = buts->start_lba;
571 if (buts->end_lba)
572 bt->end_lba = buts->end_lba;
573
574 bt->pid = buts->pid;
575 bt->trace_state = Blktrace_setup;
576
577 rcu_assign_pointer(q->blk_trace, bt);
578 get_probe_ref();
579
580 ret = 0;
581 err:
582 if (ret)
583 blk_trace_free(bt);
584 return ret;
585 }
586
587 static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
588 struct block_device *bdev, char __user *arg)
589 {
590 struct blk_user_trace_setup buts;
591 int ret;
592
593 ret = copy_from_user(&buts, arg, sizeof(buts));
594 if (ret)
595 return -EFAULT;
596
597 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
598 if (ret)
599 return ret;
600
601 if (copy_to_user(arg, &buts, sizeof(buts))) {
602 __blk_trace_remove(q);
603 return -EFAULT;
604 }
605 return 0;
606 }
607
608 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
609 struct block_device *bdev,
610 char __user *arg)
611 {
612 int ret;
613
614 mutex_lock(&q->debugfs_mutex);
615 ret = __blk_trace_setup(q, name, dev, bdev, arg);
616 mutex_unlock(&q->debugfs_mutex);
617
618 return ret;
619 }
620 EXPORT_SYMBOL_GPL(blk_trace_setup);
621
622 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
623 static int compat_blk_trace_setup(struct request_queue *q, char *name,
624 dev_t dev, struct block_device *bdev,
625 char __user *arg)
626 {
627 struct blk_user_trace_setup buts;
628 struct compat_blk_user_trace_setup cbuts;
629 int ret;
630
631 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
632 return -EFAULT;
633
634 buts = (struct blk_user_trace_setup) {
635 .act_mask = cbuts.act_mask,
636 .buf_size = cbuts.buf_size,
637 .buf_nr = cbuts.buf_nr,
638 .start_lba = cbuts.start_lba,
639 .end_lba = cbuts.end_lba,
640 .pid = cbuts.pid,
641 };
642
643 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
644 if (ret)
645 return ret;
646
647 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
648 __blk_trace_remove(q);
649 return -EFAULT;
650 }
651
652 return 0;
653 }
654 #endif
655
656 static int __blk_trace_startstop(struct request_queue *q, int start)
657 {
658 int ret;
659 struct blk_trace *bt;
660
661 bt = rcu_dereference_protected(q->blk_trace,
662 lockdep_is_held(&q->debugfs_mutex));
663 if (bt == NULL)
664 return -EINVAL;
665
666 /*
667 * For starting a trace, we can transition from a setup or stopped
668 * trace. For stopping a trace, the state must be running
669 */
670 ret = -EINVAL;
671 if (start) {
672 if (bt->trace_state == Blktrace_setup ||
673 bt->trace_state == Blktrace_stopped) {
674 blktrace_seq++;
675 smp_mb();
676 bt->trace_state = Blktrace_running;
677 spin_lock_irq(&running_trace_lock);
678 list_add(&bt->running_list, &running_trace_list);
679 spin_unlock_irq(&running_trace_lock);
680
681 trace_note_time(bt);
682 ret = 0;
683 }
684 } else {
685 if (bt->trace_state == Blktrace_running) {
686 bt->trace_state = Blktrace_stopped;
687 spin_lock_irq(&running_trace_lock);
688 list_del_init(&bt->running_list);
689 spin_unlock_irq(&running_trace_lock);
690 relay_flush(bt->rchan);
691 ret = 0;
692 }
693 }
694
695 return ret;
696 }
697
698 int blk_trace_startstop(struct request_queue *q, int start)
699 {
700 int ret;
701
702 mutex_lock(&q->debugfs_mutex);
703 ret = __blk_trace_startstop(q, start);
704 mutex_unlock(&q->debugfs_mutex);
705
706 return ret;
707 }
708 EXPORT_SYMBOL_GPL(blk_trace_startstop);
709
710 /*
711 * When reading or writing the blktrace sysfs files, the references to the
712 * opened sysfs or device files should prevent the underlying block device
713 * from being removed. So no further delete protection is really needed.
714 */
715
716 /**
717 * blk_trace_ioctl: - handle the ioctls associated with tracing
718 * @bdev: the block device
719 * @cmd: the ioctl cmd
720 * @arg: the argument data, if any
721 *
722 **/
723 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
724 {
725 struct request_queue *q;
726 int ret, start = 0;
727 char b[BDEVNAME_SIZE];
728
729 q = bdev_get_queue(bdev);
730 if (!q)
731 return -ENXIO;
732
733 mutex_lock(&q->debugfs_mutex);
734
735 switch (cmd) {
736 case BLKTRACESETUP:
737 bdevname(bdev, b);
738 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
739 break;
740 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
741 case BLKTRACESETUP32:
742 bdevname(bdev, b);
743 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
744 break;
745 #endif
746 case BLKTRACESTART:
747 start = 1;
748 fallthrough;
749 case BLKTRACESTOP:
750 ret = __blk_trace_startstop(q, start);
751 break;
752 case BLKTRACETEARDOWN:
753 ret = __blk_trace_remove(q);
754 break;
755 default:
756 ret = -ENOTTY;
757 break;
758 }
759
760 mutex_unlock(&q->debugfs_mutex);
761 return ret;
762 }
763
764 /**
765 * blk_trace_shutdown: - stop and cleanup trace structures
766 * @q: the request queue associated with the device
767 *
768 **/
769 void blk_trace_shutdown(struct request_queue *q)
770 {
771 mutex_lock(&q->debugfs_mutex);
772 if (rcu_dereference_protected(q->blk_trace,
773 lockdep_is_held(&q->debugfs_mutex))) {
774 __blk_trace_startstop(q, 0);
775 __blk_trace_remove(q);
776 }
777
778 mutex_unlock(&q->debugfs_mutex);
779 }
780
781 #ifdef CONFIG_BLK_CGROUP
782 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
783 {
784 struct blk_trace *bt;
785
786 /* We don't use the 'bt' value here except as an optimization... */
787 bt = rcu_dereference_protected(q->blk_trace, 1);
788 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
789 return 0;
790
791 if (!bio->bi_blkg)
792 return 0;
793 return cgroup_id(bio_blkcg(bio)->css.cgroup);
794 }
795 #else
796 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
797 {
798 return 0;
799 }
800 #endif
801
802 static u64
803 blk_trace_request_get_cgid(struct request_queue *q, struct request *rq)
804 {
805 if (!rq->bio)
806 return 0;
807 /* Use the first bio */
808 return blk_trace_bio_get_cgid(q, rq->bio);
809 }
810
811 /*
812 * blktrace probes
813 */
814
815 /**
816 * blk_add_trace_rq - Add a trace for a request oriented action
817 * @rq: the source request
818 * @error: return status to log
819 * @nr_bytes: number of completed bytes
820 * @what: the action
821 * @cgid: the cgroup info
822 *
823 * Description:
824 * Records an action against a request. Will log the bio offset + size.
825 *
826 **/
827 static void blk_add_trace_rq(struct request *rq, int error,
828 unsigned int nr_bytes, u32 what, u64 cgid)
829 {
830 struct blk_trace *bt;
831
832 rcu_read_lock();
833 bt = rcu_dereference(rq->q->blk_trace);
834 if (likely(!bt)) {
835 rcu_read_unlock();
836 return;
837 }
838
839 if (blk_rq_is_passthrough(rq))
840 what |= BLK_TC_ACT(BLK_TC_PC);
841 else
842 what |= BLK_TC_ACT(BLK_TC_FS);
843
844 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
845 rq->cmd_flags, what, error, 0, NULL, cgid);
846 rcu_read_unlock();
847 }
848
849 static void blk_add_trace_rq_insert(void *ignore,
850 struct request_queue *q, struct request *rq)
851 {
852 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
853 blk_trace_request_get_cgid(q, rq));
854 }
855
856 static void blk_add_trace_rq_issue(void *ignore,
857 struct request_queue *q, struct request *rq)
858 {
859 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
860 blk_trace_request_get_cgid(q, rq));
861 }
862
863 static void blk_add_trace_rq_merge(void *ignore,
864 struct request_queue *q, struct request *rq)
865 {
866 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
867 blk_trace_request_get_cgid(q, rq));
868 }
869
870 static void blk_add_trace_rq_requeue(void *ignore,
871 struct request_queue *q,
872 struct request *rq)
873 {
874 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
875 blk_trace_request_get_cgid(q, rq));
876 }
877
878 static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
879 int error, unsigned int nr_bytes)
880 {
881 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
882 blk_trace_request_get_cgid(rq->q, rq));
883 }
884
885 /**
886 * blk_add_trace_bio - Add a trace for a bio oriented action
887 * @q: queue the io is for
888 * @bio: the source bio
889 * @what: the action
890 * @error: error, if any
891 *
892 * Description:
893 * Records an action against a bio. Will log the bio offset + size.
894 *
895 **/
896 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
897 u32 what, int error)
898 {
899 struct blk_trace *bt;
900
901 rcu_read_lock();
902 bt = rcu_dereference(q->blk_trace);
903 if (likely(!bt)) {
904 rcu_read_unlock();
905 return;
906 }
907
908 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
909 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
910 blk_trace_bio_get_cgid(q, bio));
911 rcu_read_unlock();
912 }
913
914 static void blk_add_trace_bio_bounce(void *ignore,
915 struct request_queue *q, struct bio *bio)
916 {
917 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
918 }
919
920 static void blk_add_trace_bio_complete(void *ignore,
921 struct request_queue *q, struct bio *bio)
922 {
923 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
924 blk_status_to_errno(bio->bi_status));
925 }
926
927 static void blk_add_trace_bio_backmerge(void *ignore,
928 struct request_queue *q,
929 struct request *rq,
930 struct bio *bio)
931 {
932 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
933 }
934
935 static void blk_add_trace_bio_frontmerge(void *ignore,
936 struct request_queue *q,
937 struct request *rq,
938 struct bio *bio)
939 {
940 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
941 }
942
943 static void blk_add_trace_bio_queue(void *ignore,
944 struct request_queue *q, struct bio *bio)
945 {
946 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
947 }
948
949 static void blk_add_trace_getrq(void *ignore,
950 struct request_queue *q,
951 struct bio *bio, int rw)
952 {
953 if (bio)
954 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
955 else {
956 struct blk_trace *bt;
957
958 rcu_read_lock();
959 bt = rcu_dereference(q->blk_trace);
960 if (bt)
961 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
962 NULL, 0);
963 rcu_read_unlock();
964 }
965 }
966
967
968 static void blk_add_trace_sleeprq(void *ignore,
969 struct request_queue *q,
970 struct bio *bio, int rw)
971 {
972 if (bio)
973 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
974 else {
975 struct blk_trace *bt;
976
977 rcu_read_lock();
978 bt = rcu_dereference(q->blk_trace);
979 if (bt)
980 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
981 0, 0, NULL, 0);
982 rcu_read_unlock();
983 }
984 }
985
986 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
987 {
988 struct blk_trace *bt;
989
990 rcu_read_lock();
991 bt = rcu_dereference(q->blk_trace);
992 if (bt)
993 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
994 rcu_read_unlock();
995 }
996
997 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
998 unsigned int depth, bool explicit)
999 {
1000 struct blk_trace *bt;
1001
1002 rcu_read_lock();
1003 bt = rcu_dereference(q->blk_trace);
1004 if (bt) {
1005 __be64 rpdu = cpu_to_be64(depth);
1006 u32 what;
1007
1008 if (explicit)
1009 what = BLK_TA_UNPLUG_IO;
1010 else
1011 what = BLK_TA_UNPLUG_TIMER;
1012
1013 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
1014 }
1015 rcu_read_unlock();
1016 }
1017
1018 static void blk_add_trace_split(void *ignore,
1019 struct request_queue *q, struct bio *bio,
1020 unsigned int pdu)
1021 {
1022 struct blk_trace *bt;
1023
1024 rcu_read_lock();
1025 bt = rcu_dereference(q->blk_trace);
1026 if (bt) {
1027 __be64 rpdu = cpu_to_be64(pdu);
1028
1029 __blk_add_trace(bt, bio->bi_iter.bi_sector,
1030 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
1031 BLK_TA_SPLIT,
1032 blk_status_to_errno(bio->bi_status),
1033 sizeof(rpdu), &rpdu,
1034 blk_trace_bio_get_cgid(q, bio));
1035 }
1036 rcu_read_unlock();
1037 }
1038
1039 /**
1040 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
1041 * @ignore: trace callback data parameter (not used)
1042 * @q: queue the io is for
1043 * @bio: the source bio
1044 * @dev: target device
1045 * @from: source sector
1046 *
1047 * Description:
1048 * Device mapper or raid target sometimes need to split a bio because
1049 * it spans a stripe (or similar). Add a trace for that action.
1050 *
1051 **/
1052 static void blk_add_trace_bio_remap(void *ignore,
1053 struct request_queue *q, struct bio *bio,
1054 dev_t dev, sector_t from)
1055 {
1056 struct blk_trace *bt;
1057 struct blk_io_trace_remap r;
1058
1059 rcu_read_lock();
1060 bt = rcu_dereference(q->blk_trace);
1061 if (likely(!bt)) {
1062 rcu_read_unlock();
1063 return;
1064 }
1065
1066 r.device_from = cpu_to_be32(dev);
1067 r.device_to = cpu_to_be32(bio_dev(bio));
1068 r.sector_from = cpu_to_be64(from);
1069
1070 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1071 bio_op(bio), bio->bi_opf, BLK_TA_REMAP,
1072 blk_status_to_errno(bio->bi_status),
1073 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1074 rcu_read_unlock();
1075 }
1076
1077 /**
1078 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1079 * @ignore: trace callback data parameter (not used)
1080 * @q: queue the io is for
1081 * @rq: the source request
1082 * @dev: target device
1083 * @from: source sector
1084 *
1085 * Description:
1086 * Device mapper remaps request to other devices.
1087 * Add a trace for that action.
1088 *
1089 **/
1090 static void blk_add_trace_rq_remap(void *ignore,
1091 struct request_queue *q,
1092 struct request *rq, dev_t dev,
1093 sector_t from)
1094 {
1095 struct blk_trace *bt;
1096 struct blk_io_trace_remap r;
1097
1098 rcu_read_lock();
1099 bt = rcu_dereference(q->blk_trace);
1100 if (likely(!bt)) {
1101 rcu_read_unlock();
1102 return;
1103 }
1104
1105 r.device_from = cpu_to_be32(dev);
1106 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1107 r.sector_from = cpu_to_be64(from);
1108
1109 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1110 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1111 sizeof(r), &r, blk_trace_request_get_cgid(q, rq));
1112 rcu_read_unlock();
1113 }
1114
1115 /**
1116 * blk_add_driver_data - Add binary message with driver-specific data
1117 * @q: queue the io is for
1118 * @rq: io request
1119 * @data: driver-specific data
1120 * @len: length of driver-specific data
1121 *
1122 * Description:
1123 * Some drivers might want to write driver-specific data per request.
1124 *
1125 **/
1126 void blk_add_driver_data(struct request_queue *q,
1127 struct request *rq,
1128 void *data, size_t len)
1129 {
1130 struct blk_trace *bt;
1131
1132 rcu_read_lock();
1133 bt = rcu_dereference(q->blk_trace);
1134 if (likely(!bt)) {
1135 rcu_read_unlock();
1136 return;
1137 }
1138
1139 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1140 BLK_TA_DRV_DATA, 0, len, data,
1141 blk_trace_request_get_cgid(q, rq));
1142 rcu_read_unlock();
1143 }
1144 EXPORT_SYMBOL_GPL(blk_add_driver_data);
1145
1146 static void blk_register_tracepoints(void)
1147 {
1148 int ret;
1149
1150 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1151 WARN_ON(ret);
1152 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1153 WARN_ON(ret);
1154 ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1155 WARN_ON(ret);
1156 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1157 WARN_ON(ret);
1158 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1159 WARN_ON(ret);
1160 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1161 WARN_ON(ret);
1162 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1163 WARN_ON(ret);
1164 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1165 WARN_ON(ret);
1166 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1167 WARN_ON(ret);
1168 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1169 WARN_ON(ret);
1170 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1171 WARN_ON(ret);
1172 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1173 WARN_ON(ret);
1174 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1175 WARN_ON(ret);
1176 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1177 WARN_ON(ret);
1178 ret = register_trace_block_split(blk_add_trace_split, NULL);
1179 WARN_ON(ret);
1180 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1181 WARN_ON(ret);
1182 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1183 WARN_ON(ret);
1184 }
1185
1186 static void blk_unregister_tracepoints(void)
1187 {
1188 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1189 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1190 unregister_trace_block_split(blk_add_trace_split, NULL);
1191 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1192 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1193 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1194 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1195 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1196 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1197 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1198 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1199 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1200 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1201 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1202 unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1203 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1204 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1205
1206 tracepoint_synchronize_unregister();
1207 }
1208
1209 /*
1210 * struct blk_io_tracer formatting routines
1211 */
1212
1213 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1214 {
1215 int i = 0;
1216 int tc = t->action >> BLK_TC_SHIFT;
1217
1218 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1219 rwbs[i++] = 'N';
1220 goto out;
1221 }
1222
1223 if (tc & BLK_TC_FLUSH)
1224 rwbs[i++] = 'F';
1225
1226 if (tc & BLK_TC_DISCARD)
1227 rwbs[i++] = 'D';
1228 else if (tc & BLK_TC_WRITE)
1229 rwbs[i++] = 'W';
1230 else if (t->bytes)
1231 rwbs[i++] = 'R';
1232 else
1233 rwbs[i++] = 'N';
1234
1235 if (tc & BLK_TC_FUA)
1236 rwbs[i++] = 'F';
1237 if (tc & BLK_TC_AHEAD)
1238 rwbs[i++] = 'A';
1239 if (tc & BLK_TC_SYNC)
1240 rwbs[i++] = 'S';
1241 if (tc & BLK_TC_META)
1242 rwbs[i++] = 'M';
1243 out:
1244 rwbs[i] = '\0';
1245 }
1246
1247 static inline
1248 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1249 {
1250 return (const struct blk_io_trace *)ent;
1251 }
1252
1253 static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1254 {
1255 return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
1256 }
1257
1258 static inline u64 t_cgid(const struct trace_entry *ent)
1259 {
1260 return *(u64 *)(te_blk_io_trace(ent) + 1);
1261 }
1262
1263 static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1264 {
1265 return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
1266 }
1267
1268 static inline u32 t_action(const struct trace_entry *ent)
1269 {
1270 return te_blk_io_trace(ent)->action;
1271 }
1272
1273 static inline u32 t_bytes(const struct trace_entry *ent)
1274 {
1275 return te_blk_io_trace(ent)->bytes;
1276 }
1277
1278 static inline u32 t_sec(const struct trace_entry *ent)
1279 {
1280 return te_blk_io_trace(ent)->bytes >> 9;
1281 }
1282
1283 static inline unsigned long long t_sector(const struct trace_entry *ent)
1284 {
1285 return te_blk_io_trace(ent)->sector;
1286 }
1287
1288 static inline __u16 t_error(const struct trace_entry *ent)
1289 {
1290 return te_blk_io_trace(ent)->error;
1291 }
1292
1293 static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1294 {
1295 const __be64 *val = pdu_start(ent, has_cg);
1296 return be64_to_cpu(*val);
1297 }
1298
1299 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1300 bool has_cg);
1301
1302 static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1303 bool has_cg)
1304 {
1305 char rwbs[RWBS_LEN];
1306 unsigned long long ts = iter->ts;
1307 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1308 unsigned secs = (unsigned long)ts;
1309 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1310
1311 fill_rwbs(rwbs, t);
1312
1313 trace_seq_printf(&iter->seq,
1314 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1315 MAJOR(t->device), MINOR(t->device), iter->cpu,
1316 secs, nsec_rem, iter->ent->pid, act, rwbs);
1317 }
1318
1319 static void blk_log_action(struct trace_iterator *iter, const char *act,
1320 bool has_cg)
1321 {
1322 char rwbs[RWBS_LEN];
1323 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1324
1325 fill_rwbs(rwbs, t);
1326 if (has_cg) {
1327 u64 id = t_cgid(iter->ent);
1328
1329 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1330 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1331
1332 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1333 sizeof(blkcg_name_buf));
1334 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1335 MAJOR(t->device), MINOR(t->device),
1336 blkcg_name_buf, act, rwbs);
1337 } else {
1338 /*
1339 * The cgid portion used to be "INO,GEN". Userland
1340 * builds a FILEID_INO32_GEN fid out of them and
1341 * opens the cgroup using open_by_handle_at(2).
1342 * While 32bit ino setups are still the same, 64bit
1343 * ones now use the 64bit ino as the whole ID and
1344 * no longer use generation.
1345 *
1346 * Regarldess of the content, always output
1347 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
1348 * be mapped back to @id on both 64 and 32bit ino
1349 * setups. See __kernfs_fh_to_dentry().
1350 */
1351 trace_seq_printf(&iter->seq,
1352 "%3d,%-3d %llx,%-llx %2s %3s ",
1353 MAJOR(t->device), MINOR(t->device),
1354 id & U32_MAX, id >> 32, act, rwbs);
1355 }
1356 } else
1357 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1358 MAJOR(t->device), MINOR(t->device), act, rwbs);
1359 }
1360
1361 static void blk_log_dump_pdu(struct trace_seq *s,
1362 const struct trace_entry *ent, bool has_cg)
1363 {
1364 const unsigned char *pdu_buf;
1365 int pdu_len;
1366 int i, end;
1367
1368 pdu_buf = pdu_start(ent, has_cg);
1369 pdu_len = pdu_real_len(ent, has_cg);
1370
1371 if (!pdu_len)
1372 return;
1373
1374 /* find the last zero that needs to be printed */
1375 for (end = pdu_len - 1; end >= 0; end--)
1376 if (pdu_buf[end])
1377 break;
1378 end++;
1379
1380 trace_seq_putc(s, '(');
1381
1382 for (i = 0; i < pdu_len; i++) {
1383
1384 trace_seq_printf(s, "%s%02x",
1385 i == 0 ? "" : " ", pdu_buf[i]);
1386
1387 /*
1388 * stop when the rest is just zeroes and indicate so
1389 * with a ".." appended
1390 */
1391 if (i == end && end != pdu_len - 1) {
1392 trace_seq_puts(s, " ..) ");
1393 return;
1394 }
1395 }
1396
1397 trace_seq_puts(s, ") ");
1398 }
1399
1400 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1401 {
1402 char cmd[TASK_COMM_LEN];
1403
1404 trace_find_cmdline(ent->pid, cmd);
1405
1406 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1407 trace_seq_printf(s, "%u ", t_bytes(ent));
1408 blk_log_dump_pdu(s, ent, has_cg);
1409 trace_seq_printf(s, "[%s]\n", cmd);
1410 } else {
1411 if (t_sec(ent))
1412 trace_seq_printf(s, "%llu + %u [%s]\n",
1413 t_sector(ent), t_sec(ent), cmd);
1414 else
1415 trace_seq_printf(s, "[%s]\n", cmd);
1416 }
1417 }
1418
1419 static void blk_log_with_error(struct trace_seq *s,
1420 const struct trace_entry *ent, bool has_cg)
1421 {
1422 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1423 blk_log_dump_pdu(s, ent, has_cg);
1424 trace_seq_printf(s, "[%d]\n", t_error(ent));
1425 } else {
1426 if (t_sec(ent))
1427 trace_seq_printf(s, "%llu + %u [%d]\n",
1428 t_sector(ent),
1429 t_sec(ent), t_error(ent));
1430 else
1431 trace_seq_printf(s, "%llu [%d]\n",
1432 t_sector(ent), t_error(ent));
1433 }
1434 }
1435
1436 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1437 {
1438 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1439
1440 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1441 t_sector(ent), t_sec(ent),
1442 MAJOR(be32_to_cpu(__r->device_from)),
1443 MINOR(be32_to_cpu(__r->device_from)),
1444 be64_to_cpu(__r->sector_from));
1445 }
1446
1447 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1448 {
1449 char cmd[TASK_COMM_LEN];
1450
1451 trace_find_cmdline(ent->pid, cmd);
1452
1453 trace_seq_printf(s, "[%s]\n", cmd);
1454 }
1455
1456 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1457 {
1458 char cmd[TASK_COMM_LEN];
1459
1460 trace_find_cmdline(ent->pid, cmd);
1461
1462 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1463 }
1464
1465 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1466 {
1467 char cmd[TASK_COMM_LEN];
1468
1469 trace_find_cmdline(ent->pid, cmd);
1470
1471 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1472 get_pdu_int(ent, has_cg), cmd);
1473 }
1474
1475 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1476 bool has_cg)
1477 {
1478
1479 trace_seq_putmem(s, pdu_start(ent, has_cg),
1480 pdu_real_len(ent, has_cg));
1481 trace_seq_putc(s, '\n');
1482 }
1483
1484 /*
1485 * struct tracer operations
1486 */
1487
1488 static void blk_tracer_print_header(struct seq_file *m)
1489 {
1490 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1491 return;
1492 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1493 "# | | | | | |\n");
1494 }
1495
1496 static void blk_tracer_start(struct trace_array *tr)
1497 {
1498 blk_tracer_enabled = true;
1499 }
1500
1501 static int blk_tracer_init(struct trace_array *tr)
1502 {
1503 blk_tr = tr;
1504 blk_tracer_start(tr);
1505 return 0;
1506 }
1507
1508 static void blk_tracer_stop(struct trace_array *tr)
1509 {
1510 blk_tracer_enabled = false;
1511 }
1512
1513 static void blk_tracer_reset(struct trace_array *tr)
1514 {
1515 blk_tracer_stop(tr);
1516 }
1517
1518 static const struct {
1519 const char *act[2];
1520 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1521 bool has_cg);
1522 } what2act[] = {
1523 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1524 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1525 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1526 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1527 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1528 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1529 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1530 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1531 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1532 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1533 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1534 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1535 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1536 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1537 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1538 };
1539
1540 static enum print_line_t print_one_line(struct trace_iterator *iter,
1541 bool classic)
1542 {
1543 struct trace_array *tr = iter->tr;
1544 struct trace_seq *s = &iter->seq;
1545 const struct blk_io_trace *t;
1546 u16 what;
1547 bool long_act;
1548 blk_log_action_t *log_action;
1549 bool has_cg;
1550
1551 t = te_blk_io_trace(iter->ent);
1552 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1553 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1554 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1555 has_cg = t->action & __BLK_TA_CGROUP;
1556
1557 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1558 log_action(iter, long_act ? "message" : "m", has_cg);
1559 blk_log_msg(s, iter->ent, has_cg);
1560 return trace_handle_return(s);
1561 }
1562
1563 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1564 trace_seq_printf(s, "Unknown action %x\n", what);
1565 else {
1566 log_action(iter, what2act[what].act[long_act], has_cg);
1567 what2act[what].print(s, iter->ent, has_cg);
1568 }
1569
1570 return trace_handle_return(s);
1571 }
1572
1573 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1574 int flags, struct trace_event *event)
1575 {
1576 return print_one_line(iter, false);
1577 }
1578
1579 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1580 {
1581 struct trace_seq *s = &iter->seq;
1582 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1583 const int offset = offsetof(struct blk_io_trace, sector);
1584 struct blk_io_trace old = {
1585 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1586 .time = iter->ts,
1587 };
1588
1589 trace_seq_putmem(s, &old, offset);
1590 trace_seq_putmem(s, &t->sector,
1591 sizeof(old) - offset + t->pdu_len);
1592 }
1593
1594 static enum print_line_t
1595 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1596 struct trace_event *event)
1597 {
1598 blk_trace_synthesize_old_trace(iter);
1599
1600 return trace_handle_return(&iter->seq);
1601 }
1602
1603 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1604 {
1605 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1606 return TRACE_TYPE_UNHANDLED;
1607
1608 return print_one_line(iter, true);
1609 }
1610
1611 static int
1612 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1613 {
1614 /* don't output context-info for blk_classic output */
1615 if (bit == TRACE_BLK_OPT_CLASSIC) {
1616 if (set)
1617 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1618 else
1619 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1620 }
1621 return 0;
1622 }
1623
1624 static struct tracer blk_tracer __read_mostly = {
1625 .name = "blk",
1626 .init = blk_tracer_init,
1627 .reset = blk_tracer_reset,
1628 .start = blk_tracer_start,
1629 .stop = blk_tracer_stop,
1630 .print_header = blk_tracer_print_header,
1631 .print_line = blk_tracer_print_line,
1632 .flags = &blk_tracer_flags,
1633 .set_flag = blk_tracer_set_flag,
1634 };
1635
1636 static struct trace_event_functions trace_blk_event_funcs = {
1637 .trace = blk_trace_event_print,
1638 .binary = blk_trace_event_print_binary,
1639 };
1640
1641 static struct trace_event trace_blk_event = {
1642 .type = TRACE_BLK,
1643 .funcs = &trace_blk_event_funcs,
1644 };
1645
1646 static int __init init_blk_tracer(void)
1647 {
1648 if (!register_trace_event(&trace_blk_event)) {
1649 pr_warn("Warning: could not register block events\n");
1650 return 1;
1651 }
1652
1653 if (register_tracer(&blk_tracer) != 0) {
1654 pr_warn("Warning: could not register the block tracer\n");
1655 unregister_trace_event(&trace_blk_event);
1656 return 1;
1657 }
1658
1659 return 0;
1660 }
1661
1662 device_initcall(init_blk_tracer);
1663
1664 static int blk_trace_remove_queue(struct request_queue *q)
1665 {
1666 struct blk_trace *bt;
1667
1668 bt = rcu_replace_pointer(q->blk_trace, NULL,
1669 lockdep_is_held(&q->debugfs_mutex));
1670 if (bt == NULL)
1671 return -EINVAL;
1672
1673 put_probe_ref();
1674 synchronize_rcu();
1675 blk_trace_free(bt);
1676 return 0;
1677 }
1678
1679 /*
1680 * Setup everything required to start tracing
1681 */
1682 static int blk_trace_setup_queue(struct request_queue *q,
1683 struct block_device *bdev)
1684 {
1685 struct blk_trace *bt = NULL;
1686 int ret = -ENOMEM;
1687
1688 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1689 if (!bt)
1690 return -ENOMEM;
1691
1692 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1693 if (!bt->msg_data)
1694 goto free_bt;
1695
1696 bt->dev = bdev->bd_dev;
1697 bt->act_mask = (u16)-1;
1698
1699 blk_trace_setup_lba(bt, bdev);
1700
1701 rcu_assign_pointer(q->blk_trace, bt);
1702 get_probe_ref();
1703 return 0;
1704
1705 free_bt:
1706 blk_trace_free(bt);
1707 return ret;
1708 }
1709
1710 /*
1711 * sysfs interface to enable and configure tracing
1712 */
1713
1714 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1715 struct device_attribute *attr,
1716 char *buf);
1717 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1718 struct device_attribute *attr,
1719 const char *buf, size_t count);
1720 #define BLK_TRACE_DEVICE_ATTR(_name) \
1721 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1722 sysfs_blk_trace_attr_show, \
1723 sysfs_blk_trace_attr_store)
1724
1725 static BLK_TRACE_DEVICE_ATTR(enable);
1726 static BLK_TRACE_DEVICE_ATTR(act_mask);
1727 static BLK_TRACE_DEVICE_ATTR(pid);
1728 static BLK_TRACE_DEVICE_ATTR(start_lba);
1729 static BLK_TRACE_DEVICE_ATTR(end_lba);
1730
1731 static struct attribute *blk_trace_attrs[] = {
1732 &dev_attr_enable.attr,
1733 &dev_attr_act_mask.attr,
1734 &dev_attr_pid.attr,
1735 &dev_attr_start_lba.attr,
1736 &dev_attr_end_lba.attr,
1737 NULL
1738 };
1739
1740 struct attribute_group blk_trace_attr_group = {
1741 .name = "trace",
1742 .attrs = blk_trace_attrs,
1743 };
1744
1745 static const struct {
1746 int mask;
1747 const char *str;
1748 } mask_maps[] = {
1749 { BLK_TC_READ, "read" },
1750 { BLK_TC_WRITE, "write" },
1751 { BLK_TC_FLUSH, "flush" },
1752 { BLK_TC_SYNC, "sync" },
1753 { BLK_TC_QUEUE, "queue" },
1754 { BLK_TC_REQUEUE, "requeue" },
1755 { BLK_TC_ISSUE, "issue" },
1756 { BLK_TC_COMPLETE, "complete" },
1757 { BLK_TC_FS, "fs" },
1758 { BLK_TC_PC, "pc" },
1759 { BLK_TC_NOTIFY, "notify" },
1760 { BLK_TC_AHEAD, "ahead" },
1761 { BLK_TC_META, "meta" },
1762 { BLK_TC_DISCARD, "discard" },
1763 { BLK_TC_DRV_DATA, "drv_data" },
1764 { BLK_TC_FUA, "fua" },
1765 };
1766
1767 static int blk_trace_str2mask(const char *str)
1768 {
1769 int i;
1770 int mask = 0;
1771 char *buf, *s, *token;
1772
1773 buf = kstrdup(str, GFP_KERNEL);
1774 if (buf == NULL)
1775 return -ENOMEM;
1776 s = strstrip(buf);
1777
1778 while (1) {
1779 token = strsep(&s, ",");
1780 if (token == NULL)
1781 break;
1782
1783 if (*token == '\0')
1784 continue;
1785
1786 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1787 if (strcasecmp(token, mask_maps[i].str) == 0) {
1788 mask |= mask_maps[i].mask;
1789 break;
1790 }
1791 }
1792 if (i == ARRAY_SIZE(mask_maps)) {
1793 mask = -EINVAL;
1794 break;
1795 }
1796 }
1797 kfree(buf);
1798
1799 return mask;
1800 }
1801
1802 static ssize_t blk_trace_mask2str(char *buf, int mask)
1803 {
1804 int i;
1805 char *p = buf;
1806
1807 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1808 if (mask & mask_maps[i].mask) {
1809 p += sprintf(p, "%s%s",
1810 (p == buf) ? "" : ",", mask_maps[i].str);
1811 }
1812 }
1813 *p++ = '\n';
1814
1815 return p - buf;
1816 }
1817
1818 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1819 {
1820 if (bdev->bd_disk == NULL)
1821 return NULL;
1822
1823 return bdev_get_queue(bdev);
1824 }
1825
1826 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1827 struct device_attribute *attr,
1828 char *buf)
1829 {
1830 struct block_device *bdev = bdget_part(dev_to_part(dev));
1831 struct request_queue *q;
1832 struct blk_trace *bt;
1833 ssize_t ret = -ENXIO;
1834
1835 if (bdev == NULL)
1836 goto out;
1837
1838 q = blk_trace_get_queue(bdev);
1839 if (q == NULL)
1840 goto out_bdput;
1841
1842 mutex_lock(&q->debugfs_mutex);
1843
1844 bt = rcu_dereference_protected(q->blk_trace,
1845 lockdep_is_held(&q->debugfs_mutex));
1846 if (attr == &dev_attr_enable) {
1847 ret = sprintf(buf, "%u\n", !!bt);
1848 goto out_unlock_bdev;
1849 }
1850
1851 if (bt == NULL)
1852 ret = sprintf(buf, "disabled\n");
1853 else if (attr == &dev_attr_act_mask)
1854 ret = blk_trace_mask2str(buf, bt->act_mask);
1855 else if (attr == &dev_attr_pid)
1856 ret = sprintf(buf, "%u\n", bt->pid);
1857 else if (attr == &dev_attr_start_lba)
1858 ret = sprintf(buf, "%llu\n", bt->start_lba);
1859 else if (attr == &dev_attr_end_lba)
1860 ret = sprintf(buf, "%llu\n", bt->end_lba);
1861
1862 out_unlock_bdev:
1863 mutex_unlock(&q->debugfs_mutex);
1864 out_bdput:
1865 bdput(bdev);
1866 out:
1867 return ret;
1868 }
1869
1870 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1871 struct device_attribute *attr,
1872 const char *buf, size_t count)
1873 {
1874 struct block_device *bdev;
1875 struct request_queue *q;
1876 struct blk_trace *bt;
1877 u64 value;
1878 ssize_t ret = -EINVAL;
1879
1880 if (count == 0)
1881 goto out;
1882
1883 if (attr == &dev_attr_act_mask) {
1884 if (kstrtoull(buf, 0, &value)) {
1885 /* Assume it is a list of trace category names */
1886 ret = blk_trace_str2mask(buf);
1887 if (ret < 0)
1888 goto out;
1889 value = ret;
1890 }
1891 } else if (kstrtoull(buf, 0, &value))
1892 goto out;
1893
1894 ret = -ENXIO;
1895 bdev = bdget_part(dev_to_part(dev));
1896 if (bdev == NULL)
1897 goto out;
1898
1899 q = blk_trace_get_queue(bdev);
1900 if (q == NULL)
1901 goto out_bdput;
1902
1903 mutex_lock(&q->debugfs_mutex);
1904
1905 bt = rcu_dereference_protected(q->blk_trace,
1906 lockdep_is_held(&q->debugfs_mutex));
1907 if (attr == &dev_attr_enable) {
1908 if (!!value == !!bt) {
1909 ret = 0;
1910 goto out_unlock_bdev;
1911 }
1912 if (value)
1913 ret = blk_trace_setup_queue(q, bdev);
1914 else
1915 ret = blk_trace_remove_queue(q);
1916 goto out_unlock_bdev;
1917 }
1918
1919 ret = 0;
1920 if (bt == NULL) {
1921 ret = blk_trace_setup_queue(q, bdev);
1922 bt = rcu_dereference_protected(q->blk_trace,
1923 lockdep_is_held(&q->debugfs_mutex));
1924 }
1925
1926 if (ret == 0) {
1927 if (attr == &dev_attr_act_mask)
1928 bt->act_mask = value;
1929 else if (attr == &dev_attr_pid)
1930 bt->pid = value;
1931 else if (attr == &dev_attr_start_lba)
1932 bt->start_lba = value;
1933 else if (attr == &dev_attr_end_lba)
1934 bt->end_lba = value;
1935 }
1936
1937 out_unlock_bdev:
1938 mutex_unlock(&q->debugfs_mutex);
1939 out_bdput:
1940 bdput(bdev);
1941 out:
1942 return ret ? ret : count;
1943 }
1944
1945 int blk_trace_init_sysfs(struct device *dev)
1946 {
1947 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1948 }
1949
1950 void blk_trace_remove_sysfs(struct device *dev)
1951 {
1952 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1953 }
1954
1955 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1956
1957 #ifdef CONFIG_EVENT_TRACING
1958
1959 void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
1960 {
1961 int i = 0;
1962
1963 if (op & REQ_PREFLUSH)
1964 rwbs[i++] = 'F';
1965
1966 switch (op & REQ_OP_MASK) {
1967 case REQ_OP_WRITE:
1968 case REQ_OP_WRITE_SAME:
1969 rwbs[i++] = 'W';
1970 break;
1971 case REQ_OP_DISCARD:
1972 rwbs[i++] = 'D';
1973 break;
1974 case REQ_OP_SECURE_ERASE:
1975 rwbs[i++] = 'D';
1976 rwbs[i++] = 'E';
1977 break;
1978 case REQ_OP_FLUSH:
1979 rwbs[i++] = 'F';
1980 break;
1981 case REQ_OP_READ:
1982 rwbs[i++] = 'R';
1983 break;
1984 default:
1985 rwbs[i++] = 'N';
1986 }
1987
1988 if (op & REQ_FUA)
1989 rwbs[i++] = 'F';
1990 if (op & REQ_RAHEAD)
1991 rwbs[i++] = 'A';
1992 if (op & REQ_SYNC)
1993 rwbs[i++] = 'S';
1994 if (op & REQ_META)
1995 rwbs[i++] = 'M';
1996
1997 rwbs[i] = '\0';
1998 }
1999 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
2000
2001 #endif /* CONFIG_EVENT_TRACING */
2002
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