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