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