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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
31static unsigned int blktrace_seq __read_mostly = 1;
32
33static struct trace_array *blk_tr;
34static bool blk_tracer_enabled __read_mostly;
35
36static LIST_HEAD(running_trace_list);
37static __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
44static 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
54static struct tracer_flags blk_tracer_flags = {
55 .val = 0,
56 .opts = blk_tracer_opts,
57};
58
59/* Global reference count of probes */
60static DEFINE_MUTEX(blk_probe_mutex);
61static int blk_probes_ref;
62
63static void blk_register_tracepoints(void);
64static void blk_unregister_tracepoints(void);
65
66/*
67 * Send out a notify message.
68 */
69static 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());
99record_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 */
118static 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
132static 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
148void __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}
183EXPORT_SYMBOL_GPL(__blk_trace_note_message);
184
185static 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 */
201static 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 */
215static 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());
283record_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
314static 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
333static 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
341static 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
349static 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
366static 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
380static 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
388static 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
402int 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}
412EXPORT_SYMBOL_GPL(blk_trace_remove);
413
414static 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
425static 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
432static 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
452static 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 */
463static 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
476static int blk_remove_buf_file_callback(struct dentry *dentry)
477{
478 debugfs_remove(dentry);
479
480 return 0;
481}
482
483static 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
493static 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
499static 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 */
514static 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 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
528 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
529
530 /*
531 * some device names have larger paths - convert the slashes
532 * to underscores for this to work as expected
533 */
534 strreplace(buts->name, '/', '_');
535
536 /*
537 * bdev can be NULL, as with scsi-generic, this is a helpful as
538 * we can be.
539 */
540 if (rcu_dereference_protected(q->blk_trace,
541 lockdep_is_held(&q->debugfs_mutex))) {
542 pr_warn("Concurrent blktraces are not allowed on %s\n",
543 buts->name);
544 return -EBUSY;
545 }
546
547 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
548 if (!bt)
549 return -ENOMEM;
550
551 ret = -ENOMEM;
552 bt->sequence = alloc_percpu(unsigned long);
553 if (!bt->sequence)
554 goto err;
555
556 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
557 if (!bt->msg_data)
558 goto err;
559
560 /*
561 * When tracing the whole disk reuse the existing debugfs directory
562 * created by the block layer on init. For partitions block devices,
563 * and scsi-generic block devices we create a temporary new debugfs
564 * directory that will be removed once the trace ends.
565 */
566 if (bdev && !bdev_is_partition(bdev))
567 dir = q->debugfs_dir;
568 else
569 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
570
571 /*
572 * As blktrace relies on debugfs for its interface the debugfs directory
573 * is required, contrary to the usual mantra of not checking for debugfs
574 * files or directories.
575 */
576 if (IS_ERR_OR_NULL(dir)) {
577 pr_warn("debugfs_dir not present for %s so skipping\n",
578 buts->name);
579 ret = -ENOENT;
580 goto err;
581 }
582
583 bt->dev = dev;
584 atomic_set(&bt->dropped, 0);
585 INIT_LIST_HEAD(&bt->running_list);
586
587 ret = -EIO;
588 debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
589 debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
590
591 bt->rchan = relay_open("trace", dir, buts->buf_size,
592 buts->buf_nr, &blk_relay_callbacks, bt);
593 if (!bt->rchan)
594 goto err;
595
596 bt->act_mask = buts->act_mask;
597 if (!bt->act_mask)
598 bt->act_mask = (u16) -1;
599
600 blk_trace_setup_lba(bt, bdev);
601
602 /* overwrite with user settings */
603 if (buts->start_lba)
604 bt->start_lba = buts->start_lba;
605 if (buts->end_lba)
606 bt->end_lba = buts->end_lba;
607
608 bt->pid = buts->pid;
609 bt->trace_state = Blktrace_setup;
610
611 rcu_assign_pointer(q->blk_trace, bt);
612 get_probe_ref();
613
614 ret = 0;
615err:
616 if (ret)
617 blk_trace_free(q, bt);
618 return ret;
619}
620
621static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
622 struct block_device *bdev, char __user *arg)
623{
624 struct blk_user_trace_setup buts;
625 int ret;
626
627 ret = copy_from_user(&buts, arg, sizeof(buts));
628 if (ret)
629 return -EFAULT;
630
631 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
632 if (ret)
633 return ret;
634
635 if (copy_to_user(arg, &buts, sizeof(buts))) {
636 __blk_trace_remove(q);
637 return -EFAULT;
638 }
639 return 0;
640}
641
642int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
643 struct block_device *bdev,
644 char __user *arg)
645{
646 int ret;
647
648 mutex_lock(&q->debugfs_mutex);
649 ret = __blk_trace_setup(q, name, dev, bdev, arg);
650 mutex_unlock(&q->debugfs_mutex);
651
652 return ret;
653}
654EXPORT_SYMBOL_GPL(blk_trace_setup);
655
656#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
657static int compat_blk_trace_setup(struct request_queue *q, char *name,
658 dev_t dev, struct block_device *bdev,
659 char __user *arg)
660{
661 struct blk_user_trace_setup buts;
662 struct compat_blk_user_trace_setup cbuts;
663 int ret;
664
665 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
666 return -EFAULT;
667
668 buts = (struct blk_user_trace_setup) {
669 .act_mask = cbuts.act_mask,
670 .buf_size = cbuts.buf_size,
671 .buf_nr = cbuts.buf_nr,
672 .start_lba = cbuts.start_lba,
673 .end_lba = cbuts.end_lba,
674 .pid = cbuts.pid,
675 };
676
677 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
678 if (ret)
679 return ret;
680
681 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
682 __blk_trace_remove(q);
683 return -EFAULT;
684 }
685
686 return 0;
687}
688#endif
689
690static int __blk_trace_startstop(struct request_queue *q, int start)
691{
692 struct blk_trace *bt;
693
694 bt = rcu_dereference_protected(q->blk_trace,
695 lockdep_is_held(&q->debugfs_mutex));
696 if (bt == NULL)
697 return -EINVAL;
698
699 if (start)
700 return blk_trace_start(bt);
701 else
702 return blk_trace_stop(bt);
703}
704
705int blk_trace_startstop(struct request_queue *q, int start)
706{
707 int ret;
708
709 mutex_lock(&q->debugfs_mutex);
710 ret = __blk_trace_startstop(q, start);
711 mutex_unlock(&q->debugfs_mutex);
712
713 return ret;
714}
715EXPORT_SYMBOL_GPL(blk_trace_startstop);
716
717/*
718 * When reading or writing the blktrace sysfs files, the references to the
719 * opened sysfs or device files should prevent the underlying block device
720 * from being removed. So no further delete protection is really needed.
721 */
722
723/**
724 * blk_trace_ioctl - handle the ioctls associated with tracing
725 * @bdev: the block device
726 * @cmd: the ioctl cmd
727 * @arg: the argument data, if any
728 *
729 **/
730int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
731{
732 struct request_queue *q = bdev_get_queue(bdev);
733 int ret, start = 0;
734 char b[BDEVNAME_SIZE];
735
736 mutex_lock(&q->debugfs_mutex);
737
738 switch (cmd) {
739 case BLKTRACESETUP:
740 snprintf(b, sizeof(b), "%pg", bdev);
741 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
742 break;
743#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
744 case BLKTRACESETUP32:
745 snprintf(b, sizeof(b), "%pg", bdev);
746 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
747 break;
748#endif
749 case BLKTRACESTART:
750 start = 1;
751 fallthrough;
752 case BLKTRACESTOP:
753 ret = __blk_trace_startstop(q, start);
754 break;
755 case BLKTRACETEARDOWN:
756 ret = __blk_trace_remove(q);
757 break;
758 default:
759 ret = -ENOTTY;
760 break;
761 }
762
763 mutex_unlock(&q->debugfs_mutex);
764 return ret;
765}
766
767/**
768 * blk_trace_shutdown - stop and cleanup trace structures
769 * @q: the request queue associated with the device
770 *
771 **/
772void blk_trace_shutdown(struct request_queue *q)
773{
774 if (rcu_dereference_protected(q->blk_trace,
775 lockdep_is_held(&q->debugfs_mutex)))
776 __blk_trace_remove(q);
777}
778
779#ifdef CONFIG_BLK_CGROUP
780static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
781{
782 struct cgroup_subsys_state *blkcg_css;
783 struct blk_trace *bt;
784
785 /* We don't use the 'bt' value here except as an optimization... */
786 bt = rcu_dereference_protected(q->blk_trace, 1);
787 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
788 return 0;
789
790 blkcg_css = bio_blkcg_css(bio);
791 if (!blkcg_css)
792 return 0;
793 return cgroup_id(blkcg_css->cgroup);
794}
795#else
796static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
797{
798 return 0;
799}
800#endif
801
802static u64
803blk_trace_request_get_cgid(struct request *rq)
804{
805 if (!rq->bio)
806 return 0;
807 /* Use the first bio */
808 return blk_trace_bio_get_cgid(rq->q, rq->bio);
809}
810
811/*
812 * blktrace probes
813 */
814
815/**
816 * blk_add_trace_rq - Add a trace for a request oriented action
817 * @rq: the source request
818 * @error: return status to log
819 * @nr_bytes: number of completed bytes
820 * @what: the action
821 * @cgid: the cgroup info
822 *
823 * Description:
824 * Records an action against a request. Will log the bio offset + size.
825 *
826 **/
827static void blk_add_trace_rq(struct request *rq, blk_status_t error,
828 unsigned int nr_bytes, u32 what, u64 cgid)
829{
830 struct blk_trace *bt;
831
832 rcu_read_lock();
833 bt = rcu_dereference(rq->q->blk_trace);
834 if (likely(!bt)) {
835 rcu_read_unlock();
836 return;
837 }
838
839 if (blk_rq_is_passthrough(rq))
840 what |= BLK_TC_ACT(BLK_TC_PC);
841 else
842 what |= BLK_TC_ACT(BLK_TC_FS);
843
844 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, rq->cmd_flags,
845 what, blk_status_to_errno(error), 0, NULL, cgid);
846 rcu_read_unlock();
847}
848
849static void blk_add_trace_rq_insert(void *ignore, struct request *rq)
850{
851 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
852 blk_trace_request_get_cgid(rq));
853}
854
855static void blk_add_trace_rq_issue(void *ignore, struct request *rq)
856{
857 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
858 blk_trace_request_get_cgid(rq));
859}
860
861static void blk_add_trace_rq_merge(void *ignore, struct request *rq)
862{
863 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
864 blk_trace_request_get_cgid(rq));
865}
866
867static void blk_add_trace_rq_requeue(void *ignore, struct request *rq)
868{
869 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
870 blk_trace_request_get_cgid(rq));
871}
872
873static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
874 blk_status_t error, unsigned int nr_bytes)
875{
876 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
877 blk_trace_request_get_cgid(rq));
878}
879
880/**
881 * blk_add_trace_bio - Add a trace for a bio oriented action
882 * @q: queue the io is for
883 * @bio: the source bio
884 * @what: the action
885 * @error: error, if any
886 *
887 * Description:
888 * Records an action against a bio. Will log the bio offset + size.
889 *
890 **/
891static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
892 u32 what, int error)
893{
894 struct blk_trace *bt;
895
896 rcu_read_lock();
897 bt = rcu_dereference(q->blk_trace);
898 if (likely(!bt)) {
899 rcu_read_unlock();
900 return;
901 }
902
903 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
904 bio->bi_opf, what, error, 0, NULL,
905 blk_trace_bio_get_cgid(q, bio));
906 rcu_read_unlock();
907}
908
909static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio)
910{
911 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0);
912}
913
914static void blk_add_trace_bio_complete(void *ignore,
915 struct request_queue *q, struct bio *bio)
916{
917 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
918 blk_status_to_errno(bio->bi_status));
919}
920
921static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio)
922{
923 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE,
924 0);
925}
926
927static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio)
928{
929 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE,
930 0);
931}
932
933static void blk_add_trace_bio_queue(void *ignore, struct bio *bio)
934{
935 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0);
936}
937
938static void blk_add_trace_getrq(void *ignore, struct bio *bio)
939{
940 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0);
941}
942
943static void blk_add_trace_plug(void *ignore, struct request_queue *q)
944{
945 struct blk_trace *bt;
946
947 rcu_read_lock();
948 bt = rcu_dereference(q->blk_trace);
949 if (bt)
950 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
951 rcu_read_unlock();
952}
953
954static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
955 unsigned int depth, bool explicit)
956{
957 struct blk_trace *bt;
958
959 rcu_read_lock();
960 bt = rcu_dereference(q->blk_trace);
961 if (bt) {
962 __be64 rpdu = cpu_to_be64(depth);
963 u32 what;
964
965 if (explicit)
966 what = BLK_TA_UNPLUG_IO;
967 else
968 what = BLK_TA_UNPLUG_TIMER;
969
970 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
971 }
972 rcu_read_unlock();
973}
974
975static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
976{
977 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
978 struct blk_trace *bt;
979
980 rcu_read_lock();
981 bt = rcu_dereference(q->blk_trace);
982 if (bt) {
983 __be64 rpdu = cpu_to_be64(pdu);
984
985 __blk_add_trace(bt, bio->bi_iter.bi_sector,
986 bio->bi_iter.bi_size, bio->bi_opf, BLK_TA_SPLIT,
987 blk_status_to_errno(bio->bi_status),
988 sizeof(rpdu), &rpdu,
989 blk_trace_bio_get_cgid(q, bio));
990 }
991 rcu_read_unlock();
992}
993
994/**
995 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
996 * @ignore: trace callback data parameter (not used)
997 * @bio: the source bio
998 * @dev: source device
999 * @from: source sector
1000 *
1001 * Called after a bio is remapped to a different device and/or sector.
1002 **/
1003static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev,
1004 sector_t from)
1005{
1006 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
1007 struct blk_trace *bt;
1008 struct blk_io_trace_remap r;
1009
1010 rcu_read_lock();
1011 bt = rcu_dereference(q->blk_trace);
1012 if (likely(!bt)) {
1013 rcu_read_unlock();
1014 return;
1015 }
1016
1017 r.device_from = cpu_to_be32(dev);
1018 r.device_to = cpu_to_be32(bio_dev(bio));
1019 r.sector_from = cpu_to_be64(from);
1020
1021 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1022 bio->bi_opf, BLK_TA_REMAP,
1023 blk_status_to_errno(bio->bi_status),
1024 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1025 rcu_read_unlock();
1026}
1027
1028/**
1029 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1030 * @ignore: trace callback data parameter (not used)
1031 * @rq: the source request
1032 * @dev: target device
1033 * @from: source sector
1034 *
1035 * Description:
1036 * Device mapper remaps request to other devices.
1037 * Add a trace for that action.
1038 *
1039 **/
1040static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev,
1041 sector_t from)
1042{
1043 struct blk_trace *bt;
1044 struct blk_io_trace_remap r;
1045
1046 rcu_read_lock();
1047 bt = rcu_dereference(rq->q->blk_trace);
1048 if (likely(!bt)) {
1049 rcu_read_unlock();
1050 return;
1051 }
1052
1053 r.device_from = cpu_to_be32(dev);
1054 r.device_to = cpu_to_be32(disk_devt(rq->q->disk));
1055 r.sector_from = cpu_to_be64(from);
1056
1057 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1058 rq->cmd_flags, BLK_TA_REMAP, 0,
1059 sizeof(r), &r, blk_trace_request_get_cgid(rq));
1060 rcu_read_unlock();
1061}
1062
1063/**
1064 * blk_add_driver_data - Add binary message with driver-specific data
1065 * @rq: io request
1066 * @data: driver-specific data
1067 * @len: length of driver-specific data
1068 *
1069 * Description:
1070 * Some drivers might want to write driver-specific data per request.
1071 *
1072 **/
1073void blk_add_driver_data(struct request *rq, void *data, size_t len)
1074{
1075 struct blk_trace *bt;
1076
1077 rcu_read_lock();
1078 bt = rcu_dereference(rq->q->blk_trace);
1079 if (likely(!bt)) {
1080 rcu_read_unlock();
1081 return;
1082 }
1083
1084 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0,
1085 BLK_TA_DRV_DATA, 0, len, data,
1086 blk_trace_request_get_cgid(rq));
1087 rcu_read_unlock();
1088}
1089EXPORT_SYMBOL_GPL(blk_add_driver_data);
1090
1091static void blk_register_tracepoints(void)
1092{
1093 int ret;
1094
1095 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1096 WARN_ON(ret);
1097 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1098 WARN_ON(ret);
1099 ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1100 WARN_ON(ret);
1101 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1102 WARN_ON(ret);
1103 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1104 WARN_ON(ret);
1105 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1106 WARN_ON(ret);
1107 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1108 WARN_ON(ret);
1109 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1110 WARN_ON(ret);
1111 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1112 WARN_ON(ret);
1113 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1114 WARN_ON(ret);
1115 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1116 WARN_ON(ret);
1117 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1118 WARN_ON(ret);
1119 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1120 WARN_ON(ret);
1121 ret = register_trace_block_split(blk_add_trace_split, NULL);
1122 WARN_ON(ret);
1123 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1124 WARN_ON(ret);
1125 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1126 WARN_ON(ret);
1127}
1128
1129static void blk_unregister_tracepoints(void)
1130{
1131 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1132 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1133 unregister_trace_block_split(blk_add_trace_split, NULL);
1134 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1135 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1136 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1137 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1138 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1139 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1140 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1141 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1142 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1143 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1144 unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1145 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1146 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1147
1148 tracepoint_synchronize_unregister();
1149}
1150
1151/*
1152 * struct blk_io_tracer formatting routines
1153 */
1154
1155static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1156{
1157 int i = 0;
1158 int tc = t->action >> BLK_TC_SHIFT;
1159
1160 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1161 rwbs[i++] = 'N';
1162 goto out;
1163 }
1164
1165 if (tc & BLK_TC_FLUSH)
1166 rwbs[i++] = 'F';
1167
1168 if (tc & BLK_TC_DISCARD)
1169 rwbs[i++] = 'D';
1170 else if (tc & BLK_TC_WRITE)
1171 rwbs[i++] = 'W';
1172 else if (t->bytes)
1173 rwbs[i++] = 'R';
1174 else
1175 rwbs[i++] = 'N';
1176
1177 if (tc & BLK_TC_FUA)
1178 rwbs[i++] = 'F';
1179 if (tc & BLK_TC_AHEAD)
1180 rwbs[i++] = 'A';
1181 if (tc & BLK_TC_SYNC)
1182 rwbs[i++] = 'S';
1183 if (tc & BLK_TC_META)
1184 rwbs[i++] = 'M';
1185out:
1186 rwbs[i] = '\0';
1187}
1188
1189static inline
1190const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1191{
1192 return (const struct blk_io_trace *)ent;
1193}
1194
1195static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1196{
1197 return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
1198}
1199
1200static inline u64 t_cgid(const struct trace_entry *ent)
1201{
1202 return *(u64 *)(te_blk_io_trace(ent) + 1);
1203}
1204
1205static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1206{
1207 return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
1208}
1209
1210static inline u32 t_action(const struct trace_entry *ent)
1211{
1212 return te_blk_io_trace(ent)->action;
1213}
1214
1215static inline u32 t_bytes(const struct trace_entry *ent)
1216{
1217 return te_blk_io_trace(ent)->bytes;
1218}
1219
1220static inline u32 t_sec(const struct trace_entry *ent)
1221{
1222 return te_blk_io_trace(ent)->bytes >> 9;
1223}
1224
1225static inline unsigned long long t_sector(const struct trace_entry *ent)
1226{
1227 return te_blk_io_trace(ent)->sector;
1228}
1229
1230static inline __u16 t_error(const struct trace_entry *ent)
1231{
1232 return te_blk_io_trace(ent)->error;
1233}
1234
1235static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1236{
1237 const __be64 *val = pdu_start(ent, has_cg);
1238 return be64_to_cpu(*val);
1239}
1240
1241typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1242 bool has_cg);
1243
1244static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1245 bool has_cg)
1246{
1247 char rwbs[RWBS_LEN];
1248 unsigned long long ts = iter->ts;
1249 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1250 unsigned secs = (unsigned long)ts;
1251 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1252
1253 fill_rwbs(rwbs, t);
1254
1255 trace_seq_printf(&iter->seq,
1256 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1257 MAJOR(t->device), MINOR(t->device), iter->cpu,
1258 secs, nsec_rem, iter->ent->pid, act, rwbs);
1259}
1260
1261static void blk_log_action(struct trace_iterator *iter, const char *act,
1262 bool has_cg)
1263{
1264 char rwbs[RWBS_LEN];
1265 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1266
1267 fill_rwbs(rwbs, t);
1268 if (has_cg) {
1269 u64 id = t_cgid(iter->ent);
1270
1271 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1272 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1273
1274 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1275 sizeof(blkcg_name_buf));
1276 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1277 MAJOR(t->device), MINOR(t->device),
1278 blkcg_name_buf, act, rwbs);
1279 } else {
1280 /*
1281 * The cgid portion used to be "INO,GEN". Userland
1282 * builds a FILEID_INO32_GEN fid out of them and
1283 * opens the cgroup using open_by_handle_at(2).
1284 * While 32bit ino setups are still the same, 64bit
1285 * ones now use the 64bit ino as the whole ID and
1286 * no longer use generation.
1287 *
1288 * Regardless of the content, always output
1289 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
1290 * be mapped back to @id on both 64 and 32bit ino
1291 * setups. See __kernfs_fh_to_dentry().
1292 */
1293 trace_seq_printf(&iter->seq,
1294 "%3d,%-3d %llx,%-llx %2s %3s ",
1295 MAJOR(t->device), MINOR(t->device),
1296 id & U32_MAX, id >> 32, act, rwbs);
1297 }
1298 } else
1299 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1300 MAJOR(t->device), MINOR(t->device), act, rwbs);
1301}
1302
1303static void blk_log_dump_pdu(struct trace_seq *s,
1304 const struct trace_entry *ent, bool has_cg)
1305{
1306 const unsigned char *pdu_buf;
1307 int pdu_len;
1308 int i, end;
1309
1310 pdu_buf = pdu_start(ent, has_cg);
1311 pdu_len = pdu_real_len(ent, has_cg);
1312
1313 if (!pdu_len)
1314 return;
1315
1316 /* find the last zero that needs to be printed */
1317 for (end = pdu_len - 1; end >= 0; end--)
1318 if (pdu_buf[end])
1319 break;
1320 end++;
1321
1322 trace_seq_putc(s, '(');
1323
1324 for (i = 0; i < pdu_len; i++) {
1325
1326 trace_seq_printf(s, "%s%02x",
1327 i == 0 ? "" : " ", pdu_buf[i]);
1328
1329 /*
1330 * stop when the rest is just zeros and indicate so
1331 * with a ".." appended
1332 */
1333 if (i == end && end != pdu_len - 1) {
1334 trace_seq_puts(s, " ..) ");
1335 return;
1336 }
1337 }
1338
1339 trace_seq_puts(s, ") ");
1340}
1341
1342static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1343{
1344 char cmd[TASK_COMM_LEN];
1345
1346 trace_find_cmdline(ent->pid, cmd);
1347
1348 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1349 trace_seq_printf(s, "%u ", t_bytes(ent));
1350 blk_log_dump_pdu(s, ent, has_cg);
1351 trace_seq_printf(s, "[%s]\n", cmd);
1352 } else {
1353 if (t_sec(ent))
1354 trace_seq_printf(s, "%llu + %u [%s]\n",
1355 t_sector(ent), t_sec(ent), cmd);
1356 else
1357 trace_seq_printf(s, "[%s]\n", cmd);
1358 }
1359}
1360
1361static void blk_log_with_error(struct trace_seq *s,
1362 const struct trace_entry *ent, bool has_cg)
1363{
1364 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1365 blk_log_dump_pdu(s, ent, has_cg);
1366 trace_seq_printf(s, "[%d]\n", t_error(ent));
1367 } else {
1368 if (t_sec(ent))
1369 trace_seq_printf(s, "%llu + %u [%d]\n",
1370 t_sector(ent),
1371 t_sec(ent), t_error(ent));
1372 else
1373 trace_seq_printf(s, "%llu [%d]\n",
1374 t_sector(ent), t_error(ent));
1375 }
1376}
1377
1378static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1379{
1380 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1381
1382 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1383 t_sector(ent), t_sec(ent),
1384 MAJOR(be32_to_cpu(__r->device_from)),
1385 MINOR(be32_to_cpu(__r->device_from)),
1386 be64_to_cpu(__r->sector_from));
1387}
1388
1389static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1390{
1391 char cmd[TASK_COMM_LEN];
1392
1393 trace_find_cmdline(ent->pid, cmd);
1394
1395 trace_seq_printf(s, "[%s]\n", cmd);
1396}
1397
1398static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1399{
1400 char cmd[TASK_COMM_LEN];
1401
1402 trace_find_cmdline(ent->pid, cmd);
1403
1404 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1405}
1406
1407static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1408{
1409 char cmd[TASK_COMM_LEN];
1410
1411 trace_find_cmdline(ent->pid, cmd);
1412
1413 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1414 get_pdu_int(ent, has_cg), cmd);
1415}
1416
1417static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1418 bool has_cg)
1419{
1420
1421 trace_seq_putmem(s, pdu_start(ent, has_cg),
1422 pdu_real_len(ent, has_cg));
1423 trace_seq_putc(s, '\n');
1424}
1425
1426/*
1427 * struct tracer operations
1428 */
1429
1430static void blk_tracer_print_header(struct seq_file *m)
1431{
1432 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1433 return;
1434 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1435 "# | | | | | |\n");
1436}
1437
1438static void blk_tracer_start(struct trace_array *tr)
1439{
1440 blk_tracer_enabled = true;
1441}
1442
1443static int blk_tracer_init(struct trace_array *tr)
1444{
1445 blk_tr = tr;
1446 blk_tracer_start(tr);
1447 return 0;
1448}
1449
1450static void blk_tracer_stop(struct trace_array *tr)
1451{
1452 blk_tracer_enabled = false;
1453}
1454
1455static void blk_tracer_reset(struct trace_array *tr)
1456{
1457 blk_tracer_stop(tr);
1458}
1459
1460static const struct {
1461 const char *act[2];
1462 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1463 bool has_cg);
1464} what2act[] = {
1465 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1466 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1467 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1468 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1469 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1470 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1471 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1472 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1473 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1474 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1475 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1476 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1477 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1478 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1479 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1480};
1481
1482static enum print_line_t print_one_line(struct trace_iterator *iter,
1483 bool classic)
1484{
1485 struct trace_array *tr = iter->tr;
1486 struct trace_seq *s = &iter->seq;
1487 const struct blk_io_trace *t;
1488 u16 what;
1489 bool long_act;
1490 blk_log_action_t *log_action;
1491 bool has_cg;
1492
1493 t = te_blk_io_trace(iter->ent);
1494 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1495 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1496 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1497 has_cg = t->action & __BLK_TA_CGROUP;
1498
1499 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1500 log_action(iter, long_act ? "message" : "m", has_cg);
1501 blk_log_msg(s, iter->ent, has_cg);
1502 return trace_handle_return(s);
1503 }
1504
1505 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1506 trace_seq_printf(s, "Unknown action %x\n", what);
1507 else {
1508 log_action(iter, what2act[what].act[long_act], has_cg);
1509 what2act[what].print(s, iter->ent, has_cg);
1510 }
1511
1512 return trace_handle_return(s);
1513}
1514
1515static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1516 int flags, struct trace_event *event)
1517{
1518 return print_one_line(iter, false);
1519}
1520
1521static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1522{
1523 struct trace_seq *s = &iter->seq;
1524 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1525 const int offset = offsetof(struct blk_io_trace, sector);
1526 struct blk_io_trace old = {
1527 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1528 .time = iter->ts,
1529 };
1530
1531 trace_seq_putmem(s, &old, offset);
1532 trace_seq_putmem(s, &t->sector,
1533 sizeof(old) - offset + t->pdu_len);
1534}
1535
1536static enum print_line_t
1537blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1538 struct trace_event *event)
1539{
1540 blk_trace_synthesize_old_trace(iter);
1541
1542 return trace_handle_return(&iter->seq);
1543}
1544
1545static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1546{
1547 if ((iter->ent->type != TRACE_BLK) ||
1548 !(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1549 return TRACE_TYPE_UNHANDLED;
1550
1551 return print_one_line(iter, true);
1552}
1553
1554static int
1555blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1556{
1557 /* don't output context-info for blk_classic output */
1558 if (bit == TRACE_BLK_OPT_CLASSIC) {
1559 if (set)
1560 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1561 else
1562 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1563 }
1564 return 0;
1565}
1566
1567static struct tracer blk_tracer __read_mostly = {
1568 .name = "blk",
1569 .init = blk_tracer_init,
1570 .reset = blk_tracer_reset,
1571 .start = blk_tracer_start,
1572 .stop = blk_tracer_stop,
1573 .print_header = blk_tracer_print_header,
1574 .print_line = blk_tracer_print_line,
1575 .flags = &blk_tracer_flags,
1576 .set_flag = blk_tracer_set_flag,
1577};
1578
1579static struct trace_event_functions trace_blk_event_funcs = {
1580 .trace = blk_trace_event_print,
1581 .binary = blk_trace_event_print_binary,
1582};
1583
1584static struct trace_event trace_blk_event = {
1585 .type = TRACE_BLK,
1586 .funcs = &trace_blk_event_funcs,
1587};
1588
1589static int __init init_blk_tracer(void)
1590{
1591 if (!register_trace_event(&trace_blk_event)) {
1592 pr_warn("Warning: could not register block events\n");
1593 return 1;
1594 }
1595
1596 if (register_tracer(&blk_tracer) != 0) {
1597 pr_warn("Warning: could not register the block tracer\n");
1598 unregister_trace_event(&trace_blk_event);
1599 return 1;
1600 }
1601
1602 return 0;
1603}
1604
1605device_initcall(init_blk_tracer);
1606
1607static int blk_trace_remove_queue(struct request_queue *q)
1608{
1609 struct blk_trace *bt;
1610
1611 bt = rcu_replace_pointer(q->blk_trace, NULL,
1612 lockdep_is_held(&q->debugfs_mutex));
1613 if (bt == NULL)
1614 return -EINVAL;
1615
1616 blk_trace_stop(bt);
1617
1618 put_probe_ref();
1619 synchronize_rcu();
1620 blk_trace_free(q, bt);
1621 return 0;
1622}
1623
1624/*
1625 * Setup everything required to start tracing
1626 */
1627static int blk_trace_setup_queue(struct request_queue *q,
1628 struct block_device *bdev)
1629{
1630 struct blk_trace *bt = NULL;
1631 int ret = -ENOMEM;
1632
1633 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1634 if (!bt)
1635 return -ENOMEM;
1636
1637 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1638 if (!bt->msg_data)
1639 goto free_bt;
1640
1641 bt->dev = bdev->bd_dev;
1642 bt->act_mask = (u16)-1;
1643
1644 blk_trace_setup_lba(bt, bdev);
1645
1646 rcu_assign_pointer(q->blk_trace, bt);
1647 get_probe_ref();
1648 return 0;
1649
1650free_bt:
1651 blk_trace_free(q, bt);
1652 return ret;
1653}
1654
1655/*
1656 * sysfs interface to enable and configure tracing
1657 */
1658
1659static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1660 struct device_attribute *attr,
1661 char *buf);
1662static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1663 struct device_attribute *attr,
1664 const char *buf, size_t count);
1665#define BLK_TRACE_DEVICE_ATTR(_name) \
1666 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1667 sysfs_blk_trace_attr_show, \
1668 sysfs_blk_trace_attr_store)
1669
1670static BLK_TRACE_DEVICE_ATTR(enable);
1671static BLK_TRACE_DEVICE_ATTR(act_mask);
1672static BLK_TRACE_DEVICE_ATTR(pid);
1673static BLK_TRACE_DEVICE_ATTR(start_lba);
1674static BLK_TRACE_DEVICE_ATTR(end_lba);
1675
1676static struct attribute *blk_trace_attrs[] = {
1677 &dev_attr_enable.attr,
1678 &dev_attr_act_mask.attr,
1679 &dev_attr_pid.attr,
1680 &dev_attr_start_lba.attr,
1681 &dev_attr_end_lba.attr,
1682 NULL
1683};
1684
1685struct attribute_group blk_trace_attr_group = {
1686 .name = "trace",
1687 .attrs = blk_trace_attrs,
1688};
1689
1690static const struct {
1691 int mask;
1692 const char *str;
1693} mask_maps[] = {
1694 { BLK_TC_READ, "read" },
1695 { BLK_TC_WRITE, "write" },
1696 { BLK_TC_FLUSH, "flush" },
1697 { BLK_TC_SYNC, "sync" },
1698 { BLK_TC_QUEUE, "queue" },
1699 { BLK_TC_REQUEUE, "requeue" },
1700 { BLK_TC_ISSUE, "issue" },
1701 { BLK_TC_COMPLETE, "complete" },
1702 { BLK_TC_FS, "fs" },
1703 { BLK_TC_PC, "pc" },
1704 { BLK_TC_NOTIFY, "notify" },
1705 { BLK_TC_AHEAD, "ahead" },
1706 { BLK_TC_META, "meta" },
1707 { BLK_TC_DISCARD, "discard" },
1708 { BLK_TC_DRV_DATA, "drv_data" },
1709 { BLK_TC_FUA, "fua" },
1710};
1711
1712static int blk_trace_str2mask(const char *str)
1713{
1714 int i;
1715 int mask = 0;
1716 char *buf, *s, *token;
1717
1718 buf = kstrdup(str, GFP_KERNEL);
1719 if (buf == NULL)
1720 return -ENOMEM;
1721 s = strstrip(buf);
1722
1723 while (1) {
1724 token = strsep(&s, ",");
1725 if (token == NULL)
1726 break;
1727
1728 if (*token == '\0')
1729 continue;
1730
1731 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1732 if (strcasecmp(token, mask_maps[i].str) == 0) {
1733 mask |= mask_maps[i].mask;
1734 break;
1735 }
1736 }
1737 if (i == ARRAY_SIZE(mask_maps)) {
1738 mask = -EINVAL;
1739 break;
1740 }
1741 }
1742 kfree(buf);
1743
1744 return mask;
1745}
1746
1747static ssize_t blk_trace_mask2str(char *buf, int mask)
1748{
1749 int i;
1750 char *p = buf;
1751
1752 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1753 if (mask & mask_maps[i].mask) {
1754 p += sprintf(p, "%s%s",
1755 (p == buf) ? "" : ",", mask_maps[i].str);
1756 }
1757 }
1758 *p++ = '\n';
1759
1760 return p - buf;
1761}
1762
1763static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1764 struct device_attribute *attr,
1765 char *buf)
1766{
1767 struct block_device *bdev = dev_to_bdev(dev);
1768 struct request_queue *q = bdev_get_queue(bdev);
1769 struct blk_trace *bt;
1770 ssize_t ret = -ENXIO;
1771
1772 mutex_lock(&q->debugfs_mutex);
1773
1774 bt = rcu_dereference_protected(q->blk_trace,
1775 lockdep_is_held(&q->debugfs_mutex));
1776 if (attr == &dev_attr_enable) {
1777 ret = sprintf(buf, "%u\n", !!bt);
1778 goto out_unlock_bdev;
1779 }
1780
1781 if (bt == NULL)
1782 ret = sprintf(buf, "disabled\n");
1783 else if (attr == &dev_attr_act_mask)
1784 ret = blk_trace_mask2str(buf, bt->act_mask);
1785 else if (attr == &dev_attr_pid)
1786 ret = sprintf(buf, "%u\n", bt->pid);
1787 else if (attr == &dev_attr_start_lba)
1788 ret = sprintf(buf, "%llu\n", bt->start_lba);
1789 else if (attr == &dev_attr_end_lba)
1790 ret = sprintf(buf, "%llu\n", bt->end_lba);
1791
1792out_unlock_bdev:
1793 mutex_unlock(&q->debugfs_mutex);
1794 return ret;
1795}
1796
1797static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1798 struct device_attribute *attr,
1799 const char *buf, size_t count)
1800{
1801 struct block_device *bdev = dev_to_bdev(dev);
1802 struct request_queue *q = bdev_get_queue(bdev);
1803 struct blk_trace *bt;
1804 u64 value;
1805 ssize_t ret = -EINVAL;
1806
1807 if (count == 0)
1808 goto out;
1809
1810 if (attr == &dev_attr_act_mask) {
1811 if (kstrtoull(buf, 0, &value)) {
1812 /* Assume it is a list of trace category names */
1813 ret = blk_trace_str2mask(buf);
1814 if (ret < 0)
1815 goto out;
1816 value = ret;
1817 }
1818 } else {
1819 if (kstrtoull(buf, 0, &value))
1820 goto out;
1821 }
1822
1823 mutex_lock(&q->debugfs_mutex);
1824
1825 bt = rcu_dereference_protected(q->blk_trace,
1826 lockdep_is_held(&q->debugfs_mutex));
1827 if (attr == &dev_attr_enable) {
1828 if (!!value == !!bt) {
1829 ret = 0;
1830 goto out_unlock_bdev;
1831 }
1832 if (value)
1833 ret = blk_trace_setup_queue(q, bdev);
1834 else
1835 ret = blk_trace_remove_queue(q);
1836 goto out_unlock_bdev;
1837 }
1838
1839 ret = 0;
1840 if (bt == NULL) {
1841 ret = blk_trace_setup_queue(q, bdev);
1842 bt = rcu_dereference_protected(q->blk_trace,
1843 lockdep_is_held(&q->debugfs_mutex));
1844 }
1845
1846 if (ret == 0) {
1847 if (attr == &dev_attr_act_mask)
1848 bt->act_mask = value;
1849 else if (attr == &dev_attr_pid)
1850 bt->pid = value;
1851 else if (attr == &dev_attr_start_lba)
1852 bt->start_lba = value;
1853 else if (attr == &dev_attr_end_lba)
1854 bt->end_lba = value;
1855 }
1856
1857out_unlock_bdev:
1858 mutex_unlock(&q->debugfs_mutex);
1859out:
1860 return ret ? ret : count;
1861}
1862#endif /* CONFIG_BLK_DEV_IO_TRACE */
1863
1864#ifdef CONFIG_EVENT_TRACING
1865
1866/**
1867 * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string.
1868 * @rwbs: buffer to be filled
1869 * @opf: request operation type (REQ_OP_XXX) and flags for the tracepoint
1870 *
1871 * Description:
1872 * Maps each request operation and flag to a single character and fills the
1873 * buffer provided by the caller with resulting string.
1874 *
1875 **/
1876void blk_fill_rwbs(char *rwbs, blk_opf_t opf)
1877{
1878 int i = 0;
1879
1880 if (opf & REQ_PREFLUSH)
1881 rwbs[i++] = 'F';
1882
1883 switch (opf & REQ_OP_MASK) {
1884 case REQ_OP_WRITE:
1885 rwbs[i++] = 'W';
1886 break;
1887 case REQ_OP_DISCARD:
1888 rwbs[i++] = 'D';
1889 break;
1890 case REQ_OP_SECURE_ERASE:
1891 rwbs[i++] = 'D';
1892 rwbs[i++] = 'E';
1893 break;
1894 case REQ_OP_FLUSH:
1895 rwbs[i++] = 'F';
1896 break;
1897 case REQ_OP_READ:
1898 rwbs[i++] = 'R';
1899 break;
1900 default:
1901 rwbs[i++] = 'N';
1902 }
1903
1904 if (opf & REQ_FUA)
1905 rwbs[i++] = 'F';
1906 if (opf & REQ_RAHEAD)
1907 rwbs[i++] = 'A';
1908 if (opf & REQ_SYNC)
1909 rwbs[i++] = 'S';
1910 if (opf & REQ_META)
1911 rwbs[i++] = 'M';
1912
1913 rwbs[i] = '\0';
1914}
1915EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1916
1917#endif /* CONFIG_EVENT_TRACING */
1918
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
31static unsigned int blktrace_seq __read_mostly = 1;
32
33static struct trace_array *blk_tr;
34static bool blk_tracer_enabled __read_mostly;
35
36static LIST_HEAD(running_trace_list);
37static __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
44static 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
54static struct tracer_flags blk_tracer_flags = {
55 .val = 0,
56 .opts = blk_tracer_opts,
57};
58
59/* Global reference count of probes */
60static DEFINE_MUTEX(blk_probe_mutex);
61static int blk_probes_ref;
62
63static void blk_register_tracepoints(void);
64static void blk_unregister_tracepoints(void);
65
66/*
67 * Send out a notify message.
68 */
69static 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());
99record_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 */
118static 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
132static 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
148void __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}
183EXPORT_SYMBOL_GPL(__trace_note_message);
184
185static 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 */
201static 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 */
215static 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());
282record_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
313static void blk_trace_free(struct blk_trace *bt)
314{
315 relay_close(bt->rchan);
316 debugfs_remove(bt->dir);
317 free_percpu(bt->sequence);
318 free_percpu(bt->msg_data);
319 kfree(bt);
320}
321
322static void get_probe_ref(void)
323{
324 mutex_lock(&blk_probe_mutex);
325 if (++blk_probes_ref == 1)
326 blk_register_tracepoints();
327 mutex_unlock(&blk_probe_mutex);
328}
329
330static void put_probe_ref(void)
331{
332 mutex_lock(&blk_probe_mutex);
333 if (!--blk_probes_ref)
334 blk_unregister_tracepoints();
335 mutex_unlock(&blk_probe_mutex);
336}
337
338static void blk_trace_cleanup(struct blk_trace *bt)
339{
340 synchronize_rcu();
341 blk_trace_free(bt);
342 put_probe_ref();
343}
344
345static int __blk_trace_remove(struct request_queue *q)
346{
347 struct blk_trace *bt;
348
349 bt = rcu_replace_pointer(q->blk_trace, NULL,
350 lockdep_is_held(&q->debugfs_mutex));
351 if (!bt)
352 return -EINVAL;
353
354 if (bt->trace_state != Blktrace_running)
355 blk_trace_cleanup(bt);
356
357 return 0;
358}
359
360int blk_trace_remove(struct request_queue *q)
361{
362 int ret;
363
364 mutex_lock(&q->debugfs_mutex);
365 ret = __blk_trace_remove(q);
366 mutex_unlock(&q->debugfs_mutex);
367
368 return ret;
369}
370EXPORT_SYMBOL_GPL(blk_trace_remove);
371
372static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
373 size_t count, loff_t *ppos)
374{
375 struct blk_trace *bt = filp->private_data;
376 char buf[16];
377
378 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
379
380 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
381}
382
383static const struct file_operations blk_dropped_fops = {
384 .owner = THIS_MODULE,
385 .open = simple_open,
386 .read = blk_dropped_read,
387 .llseek = default_llseek,
388};
389
390static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
391 size_t count, loff_t *ppos)
392{
393 char *msg;
394 struct blk_trace *bt;
395
396 if (count >= BLK_TN_MAX_MSG)
397 return -EINVAL;
398
399 msg = memdup_user_nul(buffer, count);
400 if (IS_ERR(msg))
401 return PTR_ERR(msg);
402
403 bt = filp->private_data;
404 __trace_note_message(bt, NULL, "%s", msg);
405 kfree(msg);
406
407 return count;
408}
409
410static const struct file_operations blk_msg_fops = {
411 .owner = THIS_MODULE,
412 .open = simple_open,
413 .write = blk_msg_write,
414 .llseek = noop_llseek,
415};
416
417/*
418 * Keep track of how many times we encountered a full subbuffer, to aid
419 * the user space app in telling how many lost events there were.
420 */
421static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
422 void *prev_subbuf, size_t prev_padding)
423{
424 struct blk_trace *bt;
425
426 if (!relay_buf_full(buf))
427 return 1;
428
429 bt = buf->chan->private_data;
430 atomic_inc(&bt->dropped);
431 return 0;
432}
433
434static int blk_remove_buf_file_callback(struct dentry *dentry)
435{
436 debugfs_remove(dentry);
437
438 return 0;
439}
440
441static struct dentry *blk_create_buf_file_callback(const char *filename,
442 struct dentry *parent,
443 umode_t mode,
444 struct rchan_buf *buf,
445 int *is_global)
446{
447 return debugfs_create_file(filename, mode, parent, buf,
448 &relay_file_operations);
449}
450
451static const struct rchan_callbacks blk_relay_callbacks = {
452 .subbuf_start = blk_subbuf_start_callback,
453 .create_buf_file = blk_create_buf_file_callback,
454 .remove_buf_file = blk_remove_buf_file_callback,
455};
456
457static void blk_trace_setup_lba(struct blk_trace *bt,
458 struct block_device *bdev)
459{
460 if (bdev) {
461 bt->start_lba = bdev->bd_start_sect;
462 bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev);
463 } else {
464 bt->start_lba = 0;
465 bt->end_lba = -1ULL;
466 }
467}
468
469/*
470 * Setup everything required to start tracing
471 */
472static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
473 struct block_device *bdev,
474 struct blk_user_trace_setup *buts)
475{
476 struct blk_trace *bt = NULL;
477 struct dentry *dir = NULL;
478 int ret;
479
480 lockdep_assert_held(&q->debugfs_mutex);
481
482 if (!buts->buf_size || !buts->buf_nr)
483 return -EINVAL;
484
485 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
486 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
487
488 /*
489 * some device names have larger paths - convert the slashes
490 * to underscores for this to work as expected
491 */
492 strreplace(buts->name, '/', '_');
493
494 /*
495 * bdev can be NULL, as with scsi-generic, this is a helpful as
496 * we can be.
497 */
498 if (rcu_dereference_protected(q->blk_trace,
499 lockdep_is_held(&q->debugfs_mutex))) {
500 pr_warn("Concurrent blktraces are not allowed on %s\n",
501 buts->name);
502 return -EBUSY;
503 }
504
505 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
506 if (!bt)
507 return -ENOMEM;
508
509 ret = -ENOMEM;
510 bt->sequence = alloc_percpu(unsigned long);
511 if (!bt->sequence)
512 goto err;
513
514 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
515 if (!bt->msg_data)
516 goto err;
517
518 /*
519 * When tracing the whole disk reuse the existing debugfs directory
520 * created by the block layer on init. For partitions block devices,
521 * and scsi-generic block devices we create a temporary new debugfs
522 * directory that will be removed once the trace ends.
523 */
524 if (bdev && !bdev_is_partition(bdev))
525 dir = q->debugfs_dir;
526 else
527 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
528
529 /*
530 * As blktrace relies on debugfs for its interface the debugfs directory
531 * is required, contrary to the usual mantra of not checking for debugfs
532 * files or directories.
533 */
534 if (IS_ERR_OR_NULL(dir)) {
535 pr_warn("debugfs_dir not present for %s so skipping\n",
536 buts->name);
537 ret = -ENOENT;
538 goto err;
539 }
540
541 bt->dev = dev;
542 atomic_set(&bt->dropped, 0);
543 INIT_LIST_HEAD(&bt->running_list);
544
545 ret = -EIO;
546 debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
547 debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
548
549 bt->rchan = relay_open("trace", dir, buts->buf_size,
550 buts->buf_nr, &blk_relay_callbacks, bt);
551 if (!bt->rchan)
552 goto err;
553
554 bt->act_mask = buts->act_mask;
555 if (!bt->act_mask)
556 bt->act_mask = (u16) -1;
557
558 blk_trace_setup_lba(bt, bdev);
559
560 /* overwrite with user settings */
561 if (buts->start_lba)
562 bt->start_lba = buts->start_lba;
563 if (buts->end_lba)
564 bt->end_lba = buts->end_lba;
565
566 bt->pid = buts->pid;
567 bt->trace_state = Blktrace_setup;
568
569 rcu_assign_pointer(q->blk_trace, bt);
570 get_probe_ref();
571
572 ret = 0;
573err:
574 if (ret)
575 blk_trace_free(bt);
576 return ret;
577}
578
579static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
580 struct block_device *bdev, char __user *arg)
581{
582 struct blk_user_trace_setup buts;
583 int ret;
584
585 ret = copy_from_user(&buts, arg, sizeof(buts));
586 if (ret)
587 return -EFAULT;
588
589 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
590 if (ret)
591 return ret;
592
593 if (copy_to_user(arg, &buts, sizeof(buts))) {
594 __blk_trace_remove(q);
595 return -EFAULT;
596 }
597 return 0;
598}
599
600int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
601 struct block_device *bdev,
602 char __user *arg)
603{
604 int ret;
605
606 mutex_lock(&q->debugfs_mutex);
607 ret = __blk_trace_setup(q, name, dev, bdev, arg);
608 mutex_unlock(&q->debugfs_mutex);
609
610 return ret;
611}
612EXPORT_SYMBOL_GPL(blk_trace_setup);
613
614#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
615static int compat_blk_trace_setup(struct request_queue *q, char *name,
616 dev_t dev, struct block_device *bdev,
617 char __user *arg)
618{
619 struct blk_user_trace_setup buts;
620 struct compat_blk_user_trace_setup cbuts;
621 int ret;
622
623 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
624 return -EFAULT;
625
626 buts = (struct blk_user_trace_setup) {
627 .act_mask = cbuts.act_mask,
628 .buf_size = cbuts.buf_size,
629 .buf_nr = cbuts.buf_nr,
630 .start_lba = cbuts.start_lba,
631 .end_lba = cbuts.end_lba,
632 .pid = cbuts.pid,
633 };
634
635 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
636 if (ret)
637 return ret;
638
639 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
640 __blk_trace_remove(q);
641 return -EFAULT;
642 }
643
644 return 0;
645}
646#endif
647
648static int __blk_trace_startstop(struct request_queue *q, int start)
649{
650 int ret;
651 struct blk_trace *bt;
652
653 bt = rcu_dereference_protected(q->blk_trace,
654 lockdep_is_held(&q->debugfs_mutex));
655 if (bt == NULL)
656 return -EINVAL;
657
658 /*
659 * For starting a trace, we can transition from a setup or stopped
660 * trace. For stopping a trace, the state must be running
661 */
662 ret = -EINVAL;
663 if (start) {
664 if (bt->trace_state == Blktrace_setup ||
665 bt->trace_state == Blktrace_stopped) {
666 blktrace_seq++;
667 smp_mb();
668 bt->trace_state = Blktrace_running;
669 spin_lock_irq(&running_trace_lock);
670 list_add(&bt->running_list, &running_trace_list);
671 spin_unlock_irq(&running_trace_lock);
672
673 trace_note_time(bt);
674 ret = 0;
675 }
676 } else {
677 if (bt->trace_state == Blktrace_running) {
678 bt->trace_state = Blktrace_stopped;
679 spin_lock_irq(&running_trace_lock);
680 list_del_init(&bt->running_list);
681 spin_unlock_irq(&running_trace_lock);
682 relay_flush(bt->rchan);
683 ret = 0;
684 }
685 }
686
687 return ret;
688}
689
690int blk_trace_startstop(struct request_queue *q, int start)
691{
692 int ret;
693
694 mutex_lock(&q->debugfs_mutex);
695 ret = __blk_trace_startstop(q, start);
696 mutex_unlock(&q->debugfs_mutex);
697
698 return ret;
699}
700EXPORT_SYMBOL_GPL(blk_trace_startstop);
701
702/*
703 * When reading or writing the blktrace sysfs files, the references to the
704 * opened sysfs or device files should prevent the underlying block device
705 * from being removed. So no further delete protection is really needed.
706 */
707
708/**
709 * blk_trace_ioctl: - handle the ioctls associated with tracing
710 * @bdev: the block device
711 * @cmd: the ioctl cmd
712 * @arg: the argument data, if any
713 *
714 **/
715int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
716{
717 struct request_queue *q;
718 int ret, start = 0;
719 char b[BDEVNAME_SIZE];
720
721 q = bdev_get_queue(bdev);
722 if (!q)
723 return -ENXIO;
724
725 mutex_lock(&q->debugfs_mutex);
726
727 switch (cmd) {
728 case BLKTRACESETUP:
729 bdevname(bdev, b);
730 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
731 break;
732#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
733 case BLKTRACESETUP32:
734 bdevname(bdev, b);
735 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
736 break;
737#endif
738 case BLKTRACESTART:
739 start = 1;
740 fallthrough;
741 case BLKTRACESTOP:
742 ret = __blk_trace_startstop(q, start);
743 break;
744 case BLKTRACETEARDOWN:
745 ret = __blk_trace_remove(q);
746 break;
747 default:
748 ret = -ENOTTY;
749 break;
750 }
751
752 mutex_unlock(&q->debugfs_mutex);
753 return ret;
754}
755
756/**
757 * blk_trace_shutdown: - stop and cleanup trace structures
758 * @q: the request queue associated with the device
759 *
760 **/
761void blk_trace_shutdown(struct request_queue *q)
762{
763 mutex_lock(&q->debugfs_mutex);
764 if (rcu_dereference_protected(q->blk_trace,
765 lockdep_is_held(&q->debugfs_mutex))) {
766 __blk_trace_startstop(q, 0);
767 __blk_trace_remove(q);
768 }
769
770 mutex_unlock(&q->debugfs_mutex);
771}
772
773#ifdef CONFIG_BLK_CGROUP
774static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
775{
776 struct blk_trace *bt;
777
778 /* We don't use the 'bt' value here except as an optimization... */
779 bt = rcu_dereference_protected(q->blk_trace, 1);
780 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
781 return 0;
782
783 if (!bio->bi_blkg)
784 return 0;
785 return cgroup_id(bio_blkcg(bio)->css.cgroup);
786}
787#else
788static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
789{
790 return 0;
791}
792#endif
793
794static u64
795blk_trace_request_get_cgid(struct request *rq)
796{
797 if (!rq->bio)
798 return 0;
799 /* Use the first bio */
800 return blk_trace_bio_get_cgid(rq->q, rq->bio);
801}
802
803/*
804 * blktrace probes
805 */
806
807/**
808 * blk_add_trace_rq - Add a trace for a request oriented action
809 * @rq: the source request
810 * @error: return status to log
811 * @nr_bytes: number of completed bytes
812 * @what: the action
813 * @cgid: the cgroup info
814 *
815 * Description:
816 * Records an action against a request. Will log the bio offset + size.
817 *
818 **/
819static void blk_add_trace_rq(struct request *rq, int error,
820 unsigned int nr_bytes, u32 what, u64 cgid)
821{
822 struct blk_trace *bt;
823
824 rcu_read_lock();
825 bt = rcu_dereference(rq->q->blk_trace);
826 if (likely(!bt)) {
827 rcu_read_unlock();
828 return;
829 }
830
831 if (blk_rq_is_passthrough(rq))
832 what |= BLK_TC_ACT(BLK_TC_PC);
833 else
834 what |= BLK_TC_ACT(BLK_TC_FS);
835
836 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
837 rq->cmd_flags, what, error, 0, NULL, cgid);
838 rcu_read_unlock();
839}
840
841static void blk_add_trace_rq_insert(void *ignore, struct request *rq)
842{
843 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
844 blk_trace_request_get_cgid(rq));
845}
846
847static void blk_add_trace_rq_issue(void *ignore, struct request *rq)
848{
849 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
850 blk_trace_request_get_cgid(rq));
851}
852
853static void blk_add_trace_rq_merge(void *ignore, struct request *rq)
854{
855 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
856 blk_trace_request_get_cgid(rq));
857}
858
859static void blk_add_trace_rq_requeue(void *ignore, struct request *rq)
860{
861 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
862 blk_trace_request_get_cgid(rq));
863}
864
865static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
866 int error, unsigned int nr_bytes)
867{
868 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
869 blk_trace_request_get_cgid(rq));
870}
871
872/**
873 * blk_add_trace_bio - Add a trace for a bio oriented action
874 * @q: queue the io is for
875 * @bio: the source bio
876 * @what: the action
877 * @error: error, if any
878 *
879 * Description:
880 * Records an action against a bio. Will log the bio offset + size.
881 *
882 **/
883static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
884 u32 what, int error)
885{
886 struct blk_trace *bt;
887
888 rcu_read_lock();
889 bt = rcu_dereference(q->blk_trace);
890 if (likely(!bt)) {
891 rcu_read_unlock();
892 return;
893 }
894
895 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
896 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
897 blk_trace_bio_get_cgid(q, bio));
898 rcu_read_unlock();
899}
900
901static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio)
902{
903 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0);
904}
905
906static void blk_add_trace_bio_complete(void *ignore,
907 struct request_queue *q, struct bio *bio)
908{
909 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
910 blk_status_to_errno(bio->bi_status));
911}
912
913static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio)
914{
915 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE,
916 0);
917}
918
919static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio)
920{
921 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE,
922 0);
923}
924
925static void blk_add_trace_bio_queue(void *ignore, struct bio *bio)
926{
927 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0);
928}
929
930static void blk_add_trace_getrq(void *ignore, struct bio *bio)
931{
932 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0);
933}
934
935static void blk_add_trace_plug(void *ignore, struct request_queue *q)
936{
937 struct blk_trace *bt;
938
939 rcu_read_lock();
940 bt = rcu_dereference(q->blk_trace);
941 if (bt)
942 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
943 rcu_read_unlock();
944}
945
946static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
947 unsigned int depth, bool explicit)
948{
949 struct blk_trace *bt;
950
951 rcu_read_lock();
952 bt = rcu_dereference(q->blk_trace);
953 if (bt) {
954 __be64 rpdu = cpu_to_be64(depth);
955 u32 what;
956
957 if (explicit)
958 what = BLK_TA_UNPLUG_IO;
959 else
960 what = BLK_TA_UNPLUG_TIMER;
961
962 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
963 }
964 rcu_read_unlock();
965}
966
967static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
968{
969 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
970 struct blk_trace *bt;
971
972 rcu_read_lock();
973 bt = rcu_dereference(q->blk_trace);
974 if (bt) {
975 __be64 rpdu = cpu_to_be64(pdu);
976
977 __blk_add_trace(bt, bio->bi_iter.bi_sector,
978 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
979 BLK_TA_SPLIT,
980 blk_status_to_errno(bio->bi_status),
981 sizeof(rpdu), &rpdu,
982 blk_trace_bio_get_cgid(q, bio));
983 }
984 rcu_read_unlock();
985}
986
987/**
988 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
989 * @ignore: trace callback data parameter (not used)
990 * @bio: the source bio
991 * @dev: source device
992 * @from: source sector
993 *
994 * Called after a bio is remapped to a different device and/or sector.
995 **/
996static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev,
997 sector_t from)
998{
999 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
1000 struct blk_trace *bt;
1001 struct blk_io_trace_remap r;
1002
1003 rcu_read_lock();
1004 bt = rcu_dereference(q->blk_trace);
1005 if (likely(!bt)) {
1006 rcu_read_unlock();
1007 return;
1008 }
1009
1010 r.device_from = cpu_to_be32(dev);
1011 r.device_to = cpu_to_be32(bio_dev(bio));
1012 r.sector_from = cpu_to_be64(from);
1013
1014 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1015 bio_op(bio), bio->bi_opf, BLK_TA_REMAP,
1016 blk_status_to_errno(bio->bi_status),
1017 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1018 rcu_read_unlock();
1019}
1020
1021/**
1022 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1023 * @ignore: trace callback data parameter (not used)
1024 * @rq: the source request
1025 * @dev: target device
1026 * @from: source sector
1027 *
1028 * Description:
1029 * Device mapper remaps request to other devices.
1030 * Add a trace for that action.
1031 *
1032 **/
1033static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev,
1034 sector_t from)
1035{
1036 struct blk_trace *bt;
1037 struct blk_io_trace_remap r;
1038
1039 rcu_read_lock();
1040 bt = rcu_dereference(rq->q->blk_trace);
1041 if (likely(!bt)) {
1042 rcu_read_unlock();
1043 return;
1044 }
1045
1046 r.device_from = cpu_to_be32(dev);
1047 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1048 r.sector_from = cpu_to_be64(from);
1049
1050 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1051 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1052 sizeof(r), &r, blk_trace_request_get_cgid(rq));
1053 rcu_read_unlock();
1054}
1055
1056/**
1057 * blk_add_driver_data - Add binary message with driver-specific data
1058 * @rq: io request
1059 * @data: driver-specific data
1060 * @len: length of driver-specific data
1061 *
1062 * Description:
1063 * Some drivers might want to write driver-specific data per request.
1064 *
1065 **/
1066void blk_add_driver_data(struct request *rq, void *data, size_t len)
1067{
1068 struct blk_trace *bt;
1069
1070 rcu_read_lock();
1071 bt = rcu_dereference(rq->q->blk_trace);
1072 if (likely(!bt)) {
1073 rcu_read_unlock();
1074 return;
1075 }
1076
1077 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1078 BLK_TA_DRV_DATA, 0, len, data,
1079 blk_trace_request_get_cgid(rq));
1080 rcu_read_unlock();
1081}
1082EXPORT_SYMBOL_GPL(blk_add_driver_data);
1083
1084static void blk_register_tracepoints(void)
1085{
1086 int ret;
1087
1088 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1089 WARN_ON(ret);
1090 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1091 WARN_ON(ret);
1092 ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1093 WARN_ON(ret);
1094 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1095 WARN_ON(ret);
1096 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1097 WARN_ON(ret);
1098 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1099 WARN_ON(ret);
1100 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1101 WARN_ON(ret);
1102 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1103 WARN_ON(ret);
1104 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1105 WARN_ON(ret);
1106 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1107 WARN_ON(ret);
1108 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1109 WARN_ON(ret);
1110 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1111 WARN_ON(ret);
1112 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1113 WARN_ON(ret);
1114 ret = register_trace_block_split(blk_add_trace_split, NULL);
1115 WARN_ON(ret);
1116 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1117 WARN_ON(ret);
1118 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1119 WARN_ON(ret);
1120}
1121
1122static void blk_unregister_tracepoints(void)
1123{
1124 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1125 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1126 unregister_trace_block_split(blk_add_trace_split, NULL);
1127 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1128 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1129 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1130 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1131 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1132 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1133 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1134 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1135 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1136 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1137 unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1138 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1139 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1140
1141 tracepoint_synchronize_unregister();
1142}
1143
1144/*
1145 * struct blk_io_tracer formatting routines
1146 */
1147
1148static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1149{
1150 int i = 0;
1151 int tc = t->action >> BLK_TC_SHIFT;
1152
1153 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1154 rwbs[i++] = 'N';
1155 goto out;
1156 }
1157
1158 if (tc & BLK_TC_FLUSH)
1159 rwbs[i++] = 'F';
1160
1161 if (tc & BLK_TC_DISCARD)
1162 rwbs[i++] = 'D';
1163 else if (tc & BLK_TC_WRITE)
1164 rwbs[i++] = 'W';
1165 else if (t->bytes)
1166 rwbs[i++] = 'R';
1167 else
1168 rwbs[i++] = 'N';
1169
1170 if (tc & BLK_TC_FUA)
1171 rwbs[i++] = 'F';
1172 if (tc & BLK_TC_AHEAD)
1173 rwbs[i++] = 'A';
1174 if (tc & BLK_TC_SYNC)
1175 rwbs[i++] = 'S';
1176 if (tc & BLK_TC_META)
1177 rwbs[i++] = 'M';
1178out:
1179 rwbs[i] = '\0';
1180}
1181
1182static inline
1183const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1184{
1185 return (const struct blk_io_trace *)ent;
1186}
1187
1188static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1189{
1190 return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
1191}
1192
1193static inline u64 t_cgid(const struct trace_entry *ent)
1194{
1195 return *(u64 *)(te_blk_io_trace(ent) + 1);
1196}
1197
1198static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1199{
1200 return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
1201}
1202
1203static inline u32 t_action(const struct trace_entry *ent)
1204{
1205 return te_blk_io_trace(ent)->action;
1206}
1207
1208static inline u32 t_bytes(const struct trace_entry *ent)
1209{
1210 return te_blk_io_trace(ent)->bytes;
1211}
1212
1213static inline u32 t_sec(const struct trace_entry *ent)
1214{
1215 return te_blk_io_trace(ent)->bytes >> 9;
1216}
1217
1218static inline unsigned long long t_sector(const struct trace_entry *ent)
1219{
1220 return te_blk_io_trace(ent)->sector;
1221}
1222
1223static inline __u16 t_error(const struct trace_entry *ent)
1224{
1225 return te_blk_io_trace(ent)->error;
1226}
1227
1228static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1229{
1230 const __be64 *val = pdu_start(ent, has_cg);
1231 return be64_to_cpu(*val);
1232}
1233
1234typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1235 bool has_cg);
1236
1237static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1238 bool has_cg)
1239{
1240 char rwbs[RWBS_LEN];
1241 unsigned long long ts = iter->ts;
1242 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1243 unsigned secs = (unsigned long)ts;
1244 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1245
1246 fill_rwbs(rwbs, t);
1247
1248 trace_seq_printf(&iter->seq,
1249 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1250 MAJOR(t->device), MINOR(t->device), iter->cpu,
1251 secs, nsec_rem, iter->ent->pid, act, rwbs);
1252}
1253
1254static void blk_log_action(struct trace_iterator *iter, const char *act,
1255 bool has_cg)
1256{
1257 char rwbs[RWBS_LEN];
1258 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1259
1260 fill_rwbs(rwbs, t);
1261 if (has_cg) {
1262 u64 id = t_cgid(iter->ent);
1263
1264 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1265 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1266
1267 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1268 sizeof(blkcg_name_buf));
1269 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1270 MAJOR(t->device), MINOR(t->device),
1271 blkcg_name_buf, act, rwbs);
1272 } else {
1273 /*
1274 * The cgid portion used to be "INO,GEN". Userland
1275 * builds a FILEID_INO32_GEN fid out of them and
1276 * opens the cgroup using open_by_handle_at(2).
1277 * While 32bit ino setups are still the same, 64bit
1278 * ones now use the 64bit ino as the whole ID and
1279 * no longer use generation.
1280 *
1281 * Regardless of the content, always output
1282 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
1283 * be mapped back to @id on both 64 and 32bit ino
1284 * setups. See __kernfs_fh_to_dentry().
1285 */
1286 trace_seq_printf(&iter->seq,
1287 "%3d,%-3d %llx,%-llx %2s %3s ",
1288 MAJOR(t->device), MINOR(t->device),
1289 id & U32_MAX, id >> 32, act, rwbs);
1290 }
1291 } else
1292 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1293 MAJOR(t->device), MINOR(t->device), act, rwbs);
1294}
1295
1296static void blk_log_dump_pdu(struct trace_seq *s,
1297 const struct trace_entry *ent, bool has_cg)
1298{
1299 const unsigned char *pdu_buf;
1300 int pdu_len;
1301 int i, end;
1302
1303 pdu_buf = pdu_start(ent, has_cg);
1304 pdu_len = pdu_real_len(ent, has_cg);
1305
1306 if (!pdu_len)
1307 return;
1308
1309 /* find the last zero that needs to be printed */
1310 for (end = pdu_len - 1; end >= 0; end--)
1311 if (pdu_buf[end])
1312 break;
1313 end++;
1314
1315 trace_seq_putc(s, '(');
1316
1317 for (i = 0; i < pdu_len; i++) {
1318
1319 trace_seq_printf(s, "%s%02x",
1320 i == 0 ? "" : " ", pdu_buf[i]);
1321
1322 /*
1323 * stop when the rest is just zeros and indicate so
1324 * with a ".." appended
1325 */
1326 if (i == end && end != pdu_len - 1) {
1327 trace_seq_puts(s, " ..) ");
1328 return;
1329 }
1330 }
1331
1332 trace_seq_puts(s, ") ");
1333}
1334
1335static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1336{
1337 char cmd[TASK_COMM_LEN];
1338
1339 trace_find_cmdline(ent->pid, cmd);
1340
1341 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1342 trace_seq_printf(s, "%u ", t_bytes(ent));
1343 blk_log_dump_pdu(s, ent, has_cg);
1344 trace_seq_printf(s, "[%s]\n", cmd);
1345 } else {
1346 if (t_sec(ent))
1347 trace_seq_printf(s, "%llu + %u [%s]\n",
1348 t_sector(ent), t_sec(ent), cmd);
1349 else
1350 trace_seq_printf(s, "[%s]\n", cmd);
1351 }
1352}
1353
1354static void blk_log_with_error(struct trace_seq *s,
1355 const struct trace_entry *ent, bool has_cg)
1356{
1357 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1358 blk_log_dump_pdu(s, ent, has_cg);
1359 trace_seq_printf(s, "[%d]\n", t_error(ent));
1360 } else {
1361 if (t_sec(ent))
1362 trace_seq_printf(s, "%llu + %u [%d]\n",
1363 t_sector(ent),
1364 t_sec(ent), t_error(ent));
1365 else
1366 trace_seq_printf(s, "%llu [%d]\n",
1367 t_sector(ent), t_error(ent));
1368 }
1369}
1370
1371static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1372{
1373 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1374
1375 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1376 t_sector(ent), t_sec(ent),
1377 MAJOR(be32_to_cpu(__r->device_from)),
1378 MINOR(be32_to_cpu(__r->device_from)),
1379 be64_to_cpu(__r->sector_from));
1380}
1381
1382static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1383{
1384 char cmd[TASK_COMM_LEN];
1385
1386 trace_find_cmdline(ent->pid, cmd);
1387
1388 trace_seq_printf(s, "[%s]\n", cmd);
1389}
1390
1391static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1392{
1393 char cmd[TASK_COMM_LEN];
1394
1395 trace_find_cmdline(ent->pid, cmd);
1396
1397 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1398}
1399
1400static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1401{
1402 char cmd[TASK_COMM_LEN];
1403
1404 trace_find_cmdline(ent->pid, cmd);
1405
1406 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1407 get_pdu_int(ent, has_cg), cmd);
1408}
1409
1410static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1411 bool has_cg)
1412{
1413
1414 trace_seq_putmem(s, pdu_start(ent, has_cg),
1415 pdu_real_len(ent, has_cg));
1416 trace_seq_putc(s, '\n');
1417}
1418
1419/*
1420 * struct tracer operations
1421 */
1422
1423static void blk_tracer_print_header(struct seq_file *m)
1424{
1425 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1426 return;
1427 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1428 "# | | | | | |\n");
1429}
1430
1431static void blk_tracer_start(struct trace_array *tr)
1432{
1433 blk_tracer_enabled = true;
1434}
1435
1436static int blk_tracer_init(struct trace_array *tr)
1437{
1438 blk_tr = tr;
1439 blk_tracer_start(tr);
1440 return 0;
1441}
1442
1443static void blk_tracer_stop(struct trace_array *tr)
1444{
1445 blk_tracer_enabled = false;
1446}
1447
1448static void blk_tracer_reset(struct trace_array *tr)
1449{
1450 blk_tracer_stop(tr);
1451}
1452
1453static const struct {
1454 const char *act[2];
1455 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1456 bool has_cg);
1457} what2act[] = {
1458 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1459 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1460 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1461 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1462 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1463 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1464 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1465 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1466 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1467 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1468 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1469 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1470 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1471 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1472 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1473};
1474
1475static enum print_line_t print_one_line(struct trace_iterator *iter,
1476 bool classic)
1477{
1478 struct trace_array *tr = iter->tr;
1479 struct trace_seq *s = &iter->seq;
1480 const struct blk_io_trace *t;
1481 u16 what;
1482 bool long_act;
1483 blk_log_action_t *log_action;
1484 bool has_cg;
1485
1486 t = te_blk_io_trace(iter->ent);
1487 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1488 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1489 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1490 has_cg = t->action & __BLK_TA_CGROUP;
1491
1492 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1493 log_action(iter, long_act ? "message" : "m", has_cg);
1494 blk_log_msg(s, iter->ent, has_cg);
1495 return trace_handle_return(s);
1496 }
1497
1498 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1499 trace_seq_printf(s, "Unknown action %x\n", what);
1500 else {
1501 log_action(iter, what2act[what].act[long_act], has_cg);
1502 what2act[what].print(s, iter->ent, has_cg);
1503 }
1504
1505 return trace_handle_return(s);
1506}
1507
1508static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1509 int flags, struct trace_event *event)
1510{
1511 return print_one_line(iter, false);
1512}
1513
1514static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1515{
1516 struct trace_seq *s = &iter->seq;
1517 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1518 const int offset = offsetof(struct blk_io_trace, sector);
1519 struct blk_io_trace old = {
1520 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1521 .time = iter->ts,
1522 };
1523
1524 trace_seq_putmem(s, &old, offset);
1525 trace_seq_putmem(s, &t->sector,
1526 sizeof(old) - offset + t->pdu_len);
1527}
1528
1529static enum print_line_t
1530blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1531 struct trace_event *event)
1532{
1533 blk_trace_synthesize_old_trace(iter);
1534
1535 return trace_handle_return(&iter->seq);
1536}
1537
1538static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1539{
1540 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1541 return TRACE_TYPE_UNHANDLED;
1542
1543 return print_one_line(iter, true);
1544}
1545
1546static int
1547blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1548{
1549 /* don't output context-info for blk_classic output */
1550 if (bit == TRACE_BLK_OPT_CLASSIC) {
1551 if (set)
1552 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1553 else
1554 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1555 }
1556 return 0;
1557}
1558
1559static struct tracer blk_tracer __read_mostly = {
1560 .name = "blk",
1561 .init = blk_tracer_init,
1562 .reset = blk_tracer_reset,
1563 .start = blk_tracer_start,
1564 .stop = blk_tracer_stop,
1565 .print_header = blk_tracer_print_header,
1566 .print_line = blk_tracer_print_line,
1567 .flags = &blk_tracer_flags,
1568 .set_flag = blk_tracer_set_flag,
1569};
1570
1571static struct trace_event_functions trace_blk_event_funcs = {
1572 .trace = blk_trace_event_print,
1573 .binary = blk_trace_event_print_binary,
1574};
1575
1576static struct trace_event trace_blk_event = {
1577 .type = TRACE_BLK,
1578 .funcs = &trace_blk_event_funcs,
1579};
1580
1581static int __init init_blk_tracer(void)
1582{
1583 if (!register_trace_event(&trace_blk_event)) {
1584 pr_warn("Warning: could not register block events\n");
1585 return 1;
1586 }
1587
1588 if (register_tracer(&blk_tracer) != 0) {
1589 pr_warn("Warning: could not register the block tracer\n");
1590 unregister_trace_event(&trace_blk_event);
1591 return 1;
1592 }
1593
1594 return 0;
1595}
1596
1597device_initcall(init_blk_tracer);
1598
1599static int blk_trace_remove_queue(struct request_queue *q)
1600{
1601 struct blk_trace *bt;
1602
1603 bt = rcu_replace_pointer(q->blk_trace, NULL,
1604 lockdep_is_held(&q->debugfs_mutex));
1605 if (bt == NULL)
1606 return -EINVAL;
1607
1608 if (bt->trace_state == Blktrace_running) {
1609 bt->trace_state = Blktrace_stopped;
1610 spin_lock_irq(&running_trace_lock);
1611 list_del_init(&bt->running_list);
1612 spin_unlock_irq(&running_trace_lock);
1613 relay_flush(bt->rchan);
1614 }
1615
1616 put_probe_ref();
1617 synchronize_rcu();
1618 blk_trace_free(bt);
1619 return 0;
1620}
1621
1622/*
1623 * Setup everything required to start tracing
1624 */
1625static int blk_trace_setup_queue(struct request_queue *q,
1626 struct block_device *bdev)
1627{
1628 struct blk_trace *bt = NULL;
1629 int ret = -ENOMEM;
1630
1631 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1632 if (!bt)
1633 return -ENOMEM;
1634
1635 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1636 if (!bt->msg_data)
1637 goto free_bt;
1638
1639 bt->dev = bdev->bd_dev;
1640 bt->act_mask = (u16)-1;
1641
1642 blk_trace_setup_lba(bt, bdev);
1643
1644 rcu_assign_pointer(q->blk_trace, bt);
1645 get_probe_ref();
1646 return 0;
1647
1648free_bt:
1649 blk_trace_free(bt);
1650 return ret;
1651}
1652
1653/*
1654 * sysfs interface to enable and configure tracing
1655 */
1656
1657static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1658 struct device_attribute *attr,
1659 char *buf);
1660static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1661 struct device_attribute *attr,
1662 const char *buf, size_t count);
1663#define BLK_TRACE_DEVICE_ATTR(_name) \
1664 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1665 sysfs_blk_trace_attr_show, \
1666 sysfs_blk_trace_attr_store)
1667
1668static BLK_TRACE_DEVICE_ATTR(enable);
1669static BLK_TRACE_DEVICE_ATTR(act_mask);
1670static BLK_TRACE_DEVICE_ATTR(pid);
1671static BLK_TRACE_DEVICE_ATTR(start_lba);
1672static BLK_TRACE_DEVICE_ATTR(end_lba);
1673
1674static struct attribute *blk_trace_attrs[] = {
1675 &dev_attr_enable.attr,
1676 &dev_attr_act_mask.attr,
1677 &dev_attr_pid.attr,
1678 &dev_attr_start_lba.attr,
1679 &dev_attr_end_lba.attr,
1680 NULL
1681};
1682
1683struct attribute_group blk_trace_attr_group = {
1684 .name = "trace",
1685 .attrs = blk_trace_attrs,
1686};
1687
1688static const struct {
1689 int mask;
1690 const char *str;
1691} mask_maps[] = {
1692 { BLK_TC_READ, "read" },
1693 { BLK_TC_WRITE, "write" },
1694 { BLK_TC_FLUSH, "flush" },
1695 { BLK_TC_SYNC, "sync" },
1696 { BLK_TC_QUEUE, "queue" },
1697 { BLK_TC_REQUEUE, "requeue" },
1698 { BLK_TC_ISSUE, "issue" },
1699 { BLK_TC_COMPLETE, "complete" },
1700 { BLK_TC_FS, "fs" },
1701 { BLK_TC_PC, "pc" },
1702 { BLK_TC_NOTIFY, "notify" },
1703 { BLK_TC_AHEAD, "ahead" },
1704 { BLK_TC_META, "meta" },
1705 { BLK_TC_DISCARD, "discard" },
1706 { BLK_TC_DRV_DATA, "drv_data" },
1707 { BLK_TC_FUA, "fua" },
1708};
1709
1710static int blk_trace_str2mask(const char *str)
1711{
1712 int i;
1713 int mask = 0;
1714 char *buf, *s, *token;
1715
1716 buf = kstrdup(str, GFP_KERNEL);
1717 if (buf == NULL)
1718 return -ENOMEM;
1719 s = strstrip(buf);
1720
1721 while (1) {
1722 token = strsep(&s, ",");
1723 if (token == NULL)
1724 break;
1725
1726 if (*token == '\0')
1727 continue;
1728
1729 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1730 if (strcasecmp(token, mask_maps[i].str) == 0) {
1731 mask |= mask_maps[i].mask;
1732 break;
1733 }
1734 }
1735 if (i == ARRAY_SIZE(mask_maps)) {
1736 mask = -EINVAL;
1737 break;
1738 }
1739 }
1740 kfree(buf);
1741
1742 return mask;
1743}
1744
1745static ssize_t blk_trace_mask2str(char *buf, int mask)
1746{
1747 int i;
1748 char *p = buf;
1749
1750 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1751 if (mask & mask_maps[i].mask) {
1752 p += sprintf(p, "%s%s",
1753 (p == buf) ? "" : ",", mask_maps[i].str);
1754 }
1755 }
1756 *p++ = '\n';
1757
1758 return p - buf;
1759}
1760
1761static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1762 struct device_attribute *attr,
1763 char *buf)
1764{
1765 struct block_device *bdev = dev_to_bdev(dev);
1766 struct request_queue *q = bdev_get_queue(bdev);
1767 struct blk_trace *bt;
1768 ssize_t ret = -ENXIO;
1769
1770 mutex_lock(&q->debugfs_mutex);
1771
1772 bt = rcu_dereference_protected(q->blk_trace,
1773 lockdep_is_held(&q->debugfs_mutex));
1774 if (attr == &dev_attr_enable) {
1775 ret = sprintf(buf, "%u\n", !!bt);
1776 goto out_unlock_bdev;
1777 }
1778
1779 if (bt == NULL)
1780 ret = sprintf(buf, "disabled\n");
1781 else if (attr == &dev_attr_act_mask)
1782 ret = blk_trace_mask2str(buf, bt->act_mask);
1783 else if (attr == &dev_attr_pid)
1784 ret = sprintf(buf, "%u\n", bt->pid);
1785 else if (attr == &dev_attr_start_lba)
1786 ret = sprintf(buf, "%llu\n", bt->start_lba);
1787 else if (attr == &dev_attr_end_lba)
1788 ret = sprintf(buf, "%llu\n", bt->end_lba);
1789
1790out_unlock_bdev:
1791 mutex_unlock(&q->debugfs_mutex);
1792 return ret;
1793}
1794
1795static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1796 struct device_attribute *attr,
1797 const char *buf, size_t count)
1798{
1799 struct block_device *bdev = dev_to_bdev(dev);
1800 struct request_queue *q = bdev_get_queue(bdev);
1801 struct blk_trace *bt;
1802 u64 value;
1803 ssize_t ret = -EINVAL;
1804
1805 if (count == 0)
1806 goto out;
1807
1808 if (attr == &dev_attr_act_mask) {
1809 if (kstrtoull(buf, 0, &value)) {
1810 /* Assume it is a list of trace category names */
1811 ret = blk_trace_str2mask(buf);
1812 if (ret < 0)
1813 goto out;
1814 value = ret;
1815 }
1816 } else {
1817 if (kstrtoull(buf, 0, &value))
1818 goto out;
1819 }
1820
1821 mutex_lock(&q->debugfs_mutex);
1822
1823 bt = rcu_dereference_protected(q->blk_trace,
1824 lockdep_is_held(&q->debugfs_mutex));
1825 if (attr == &dev_attr_enable) {
1826 if (!!value == !!bt) {
1827 ret = 0;
1828 goto out_unlock_bdev;
1829 }
1830 if (value)
1831 ret = blk_trace_setup_queue(q, bdev);
1832 else
1833 ret = blk_trace_remove_queue(q);
1834 goto out_unlock_bdev;
1835 }
1836
1837 ret = 0;
1838 if (bt == NULL) {
1839 ret = blk_trace_setup_queue(q, bdev);
1840 bt = rcu_dereference_protected(q->blk_trace,
1841 lockdep_is_held(&q->debugfs_mutex));
1842 }
1843
1844 if (ret == 0) {
1845 if (attr == &dev_attr_act_mask)
1846 bt->act_mask = value;
1847 else if (attr == &dev_attr_pid)
1848 bt->pid = value;
1849 else if (attr == &dev_attr_start_lba)
1850 bt->start_lba = value;
1851 else if (attr == &dev_attr_end_lba)
1852 bt->end_lba = value;
1853 }
1854
1855out_unlock_bdev:
1856 mutex_unlock(&q->debugfs_mutex);
1857out:
1858 return ret ? ret : count;
1859}
1860
1861int blk_trace_init_sysfs(struct device *dev)
1862{
1863 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1864}
1865
1866void blk_trace_remove_sysfs(struct device *dev)
1867{
1868 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1869}
1870
1871#endif /* CONFIG_BLK_DEV_IO_TRACE */
1872
1873#ifdef CONFIG_EVENT_TRACING
1874
1875/**
1876 * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string.
1877 * @rwbs: buffer to be filled
1878 * @op: REQ_OP_XXX for the tracepoint
1879 *
1880 * Description:
1881 * Maps the REQ_OP_XXX to character and fills the buffer provided by the
1882 * caller with resulting string.
1883 *
1884 **/
1885void blk_fill_rwbs(char *rwbs, unsigned int op)
1886{
1887 int i = 0;
1888
1889 if (op & REQ_PREFLUSH)
1890 rwbs[i++] = 'F';
1891
1892 switch (op & REQ_OP_MASK) {
1893 case REQ_OP_WRITE:
1894 case REQ_OP_WRITE_SAME:
1895 rwbs[i++] = 'W';
1896 break;
1897 case REQ_OP_DISCARD:
1898 rwbs[i++] = 'D';
1899 break;
1900 case REQ_OP_SECURE_ERASE:
1901 rwbs[i++] = 'D';
1902 rwbs[i++] = 'E';
1903 break;
1904 case REQ_OP_FLUSH:
1905 rwbs[i++] = 'F';
1906 break;
1907 case REQ_OP_READ:
1908 rwbs[i++] = 'R';
1909 break;
1910 default:
1911 rwbs[i++] = 'N';
1912 }
1913
1914 if (op & REQ_FUA)
1915 rwbs[i++] = 'F';
1916 if (op & REQ_RAHEAD)
1917 rwbs[i++] = 'A';
1918 if (op & REQ_SYNC)
1919 rwbs[i++] = 'S';
1920 if (op & REQ_META)
1921 rwbs[i++] = 'M';
1922
1923 rwbs[i] = '\0';
1924}
1925EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1926
1927#endif /* CONFIG_EVENT_TRACING */
1928