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1/*
2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
16 *
17 */
18#include <linux/kernel.h>
19#include <linux/blkdev.h>
20#include <linux/blktrace_api.h>
21#include <linux/percpu.h>
22#include <linux/init.h>
23#include <linux/mutex.h>
24#include <linux/slab.h>
25#include <linux/debugfs.h>
26#include <linux/export.h>
27#include <linux/time.h>
28#include <linux/uaccess.h>
29#include <linux/list.h>
30#include <linux/blk-cgroup.h>
31
32#include "../../block/blk.h"
33
34#include <trace/events/block.h>
35
36#include "trace_output.h"
37
38#ifdef CONFIG_BLK_DEV_IO_TRACE
39
40static unsigned int blktrace_seq __read_mostly = 1;
41
42static struct trace_array *blk_tr;
43static bool blk_tracer_enabled __read_mostly;
44
45static LIST_HEAD(running_trace_list);
46static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
47
48/* Select an alternative, minimalistic output than the original one */
49#define TRACE_BLK_OPT_CLASSIC 0x1
50#define TRACE_BLK_OPT_CGROUP 0x2
51#define TRACE_BLK_OPT_CGNAME 0x4
52
53static struct tracer_opt blk_tracer_opts[] = {
54 /* Default disable the minimalistic output */
55 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
56#ifdef CONFIG_BLK_CGROUP
57 { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
58 { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
59#endif
60 { }
61};
62
63static struct tracer_flags blk_tracer_flags = {
64 .val = 0,
65 .opts = blk_tracer_opts,
66};
67
68/* Global reference count of probes */
69static DEFINE_MUTEX(blk_probe_mutex);
70static int blk_probes_ref;
71
72static void blk_register_tracepoints(void);
73static void blk_unregister_tracepoints(void);
74
75/*
76 * Send out a notify message.
77 */
78static void trace_note(struct blk_trace *bt, pid_t pid, int action,
79 const void *data, size_t len,
80 union kernfs_node_id *cgid)
81{
82 struct blk_io_trace *t;
83 struct ring_buffer_event *event = NULL;
84 struct ring_buffer *buffer = NULL;
85 int pc = 0;
86 int cpu = smp_processor_id();
87 bool blk_tracer = blk_tracer_enabled;
88 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
89
90 if (blk_tracer) {
91 buffer = blk_tr->trace_buffer.buffer;
92 pc = preempt_count();
93 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
94 sizeof(*t) + len + cgid_len,
95 0, pc);
96 if (!event)
97 return;
98 t = ring_buffer_event_data(event);
99 goto record_it;
100 }
101
102 if (!bt->rchan)
103 return;
104
105 t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len);
106 if (t) {
107 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
108 t->time = ktime_to_ns(ktime_get());
109record_it:
110 t->device = bt->dev;
111 t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
112 t->pid = pid;
113 t->cpu = cpu;
114 t->pdu_len = len + cgid_len;
115 if (cgid)
116 memcpy((void *)t + sizeof(*t), cgid, cgid_len);
117 memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
118
119 if (blk_tracer)
120 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
121 }
122}
123
124/*
125 * Send out a notify for this process, if we haven't done so since a trace
126 * started
127 */
128static void trace_note_tsk(struct task_struct *tsk)
129{
130 unsigned long flags;
131 struct blk_trace *bt;
132
133 tsk->btrace_seq = blktrace_seq;
134 spin_lock_irqsave(&running_trace_lock, flags);
135 list_for_each_entry(bt, &running_trace_list, running_list) {
136 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
137 sizeof(tsk->comm), NULL);
138 }
139 spin_unlock_irqrestore(&running_trace_lock, flags);
140}
141
142static void trace_note_time(struct blk_trace *bt)
143{
144 struct timespec64 now;
145 unsigned long flags;
146 u32 words[2];
147
148 /* need to check user space to see if this breaks in y2038 or y2106 */
149 ktime_get_real_ts64(&now);
150 words[0] = (u32)now.tv_sec;
151 words[1] = now.tv_nsec;
152
153 local_irq_save(flags);
154 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), NULL);
155 local_irq_restore(flags);
156}
157
158void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
159 const char *fmt, ...)
160{
161 int n;
162 va_list args;
163 unsigned long flags;
164 char *buf;
165
166 if (unlikely(bt->trace_state != Blktrace_running &&
167 !blk_tracer_enabled))
168 return;
169
170 /*
171 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
172 * message to the trace.
173 */
174 if (!(bt->act_mask & BLK_TC_NOTIFY))
175 return;
176
177 local_irq_save(flags);
178 buf = this_cpu_ptr(bt->msg_data);
179 va_start(args, fmt);
180 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
181 va_end(args);
182
183 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
184 blkcg = NULL;
185#ifdef CONFIG_BLK_CGROUP
186 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n,
187 blkcg ? cgroup_get_kernfs_id(blkcg->css.cgroup) : NULL);
188#else
189 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL);
190#endif
191 local_irq_restore(flags);
192}
193EXPORT_SYMBOL_GPL(__trace_note_message);
194
195static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
196 pid_t pid)
197{
198 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
199 return 1;
200 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
201 return 1;
202 if (bt->pid && pid != bt->pid)
203 return 1;
204
205 return 0;
206}
207
208/*
209 * Data direction bit lookup
210 */
211static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
212 BLK_TC_ACT(BLK_TC_WRITE) };
213
214#define BLK_TC_RAHEAD BLK_TC_AHEAD
215#define BLK_TC_PREFLUSH BLK_TC_FLUSH
216
217/* The ilog2() calls fall out because they're constant */
218#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
219 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
220
221/*
222 * The worker for the various blk_add_trace*() types. Fills out a
223 * blk_io_trace structure and places it in a per-cpu subbuffer.
224 */
225static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
226 int op, int op_flags, u32 what, int error, int pdu_len,
227 void *pdu_data, union kernfs_node_id *cgid)
228{
229 struct task_struct *tsk = current;
230 struct ring_buffer_event *event = NULL;
231 struct ring_buffer *buffer = NULL;
232 struct blk_io_trace *t;
233 unsigned long flags = 0;
234 unsigned long *sequence;
235 pid_t pid;
236 int cpu, pc = 0;
237 bool blk_tracer = blk_tracer_enabled;
238 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
239
240 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
241 return;
242
243 what |= ddir_act[op_is_write(op) ? WRITE : READ];
244 what |= MASK_TC_BIT(op_flags, SYNC);
245 what |= MASK_TC_BIT(op_flags, RAHEAD);
246 what |= MASK_TC_BIT(op_flags, META);
247 what |= MASK_TC_BIT(op_flags, PREFLUSH);
248 what |= MASK_TC_BIT(op_flags, FUA);
249 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
250 what |= BLK_TC_ACT(BLK_TC_DISCARD);
251 if (op == REQ_OP_FLUSH)
252 what |= BLK_TC_ACT(BLK_TC_FLUSH);
253 if (cgid)
254 what |= __BLK_TA_CGROUP;
255
256 pid = tsk->pid;
257 if (act_log_check(bt, what, sector, pid))
258 return;
259 cpu = raw_smp_processor_id();
260
261 if (blk_tracer) {
262 tracing_record_cmdline(current);
263
264 buffer = blk_tr->trace_buffer.buffer;
265 pc = preempt_count();
266 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
267 sizeof(*t) + pdu_len + cgid_len,
268 0, pc);
269 if (!event)
270 return;
271 t = ring_buffer_event_data(event);
272 goto record_it;
273 }
274
275 if (unlikely(tsk->btrace_seq != blktrace_seq))
276 trace_note_tsk(tsk);
277
278 /*
279 * A word about the locking here - we disable interrupts to reserve
280 * some space in the relay per-cpu buffer, to prevent an irq
281 * from coming in and stepping on our toes.
282 */
283 local_irq_save(flags);
284 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
285 if (t) {
286 sequence = per_cpu_ptr(bt->sequence, cpu);
287
288 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
289 t->sequence = ++(*sequence);
290 t->time = ktime_to_ns(ktime_get());
291record_it:
292 /*
293 * These two are not needed in ftrace as they are in the
294 * generic trace_entry, filled by tracing_generic_entry_update,
295 * but for the trace_event->bin() synthesizer benefit we do it
296 * here too.
297 */
298 t->cpu = cpu;
299 t->pid = pid;
300
301 t->sector = sector;
302 t->bytes = bytes;
303 t->action = what;
304 t->device = bt->dev;
305 t->error = error;
306 t->pdu_len = pdu_len + cgid_len;
307
308 if (cgid_len)
309 memcpy((void *)t + sizeof(*t), cgid, cgid_len);
310 if (pdu_len)
311 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
312
313 if (blk_tracer) {
314 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
315 return;
316 }
317 }
318
319 local_irq_restore(flags);
320}
321
322static void blk_trace_free(struct blk_trace *bt)
323{
324 debugfs_remove(bt->msg_file);
325 debugfs_remove(bt->dropped_file);
326 relay_close(bt->rchan);
327 debugfs_remove(bt->dir);
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 void blk_trace_cleanup(struct blk_trace *bt)
350{
351 blk_trace_free(bt);
352 put_probe_ref();
353}
354
355static int __blk_trace_remove(struct request_queue *q)
356{
357 struct blk_trace *bt;
358
359 bt = xchg(&q->blk_trace, NULL);
360 if (!bt)
361 return -EINVAL;
362
363 if (bt->trace_state != Blktrace_running)
364 blk_trace_cleanup(bt);
365
366 return 0;
367}
368
369int blk_trace_remove(struct request_queue *q)
370{
371 int ret;
372
373 mutex_lock(&q->blk_trace_mutex);
374 ret = __blk_trace_remove(q);
375 mutex_unlock(&q->blk_trace_mutex);
376
377 return ret;
378}
379EXPORT_SYMBOL_GPL(blk_trace_remove);
380
381static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
382 size_t count, loff_t *ppos)
383{
384 struct blk_trace *bt = filp->private_data;
385 char buf[16];
386
387 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
388
389 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
390}
391
392static const struct file_operations blk_dropped_fops = {
393 .owner = THIS_MODULE,
394 .open = simple_open,
395 .read = blk_dropped_read,
396 .llseek = default_llseek,
397};
398
399static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
400 size_t count, loff_t *ppos)
401{
402 char *msg;
403 struct blk_trace *bt;
404
405 if (count >= BLK_TN_MAX_MSG)
406 return -EINVAL;
407
408 msg = memdup_user_nul(buffer, count);
409 if (IS_ERR(msg))
410 return PTR_ERR(msg);
411
412 bt = filp->private_data;
413 __trace_note_message(bt, NULL, "%s", msg);
414 kfree(msg);
415
416 return count;
417}
418
419static const struct file_operations blk_msg_fops = {
420 .owner = THIS_MODULE,
421 .open = simple_open,
422 .write = blk_msg_write,
423 .llseek = noop_llseek,
424};
425
426/*
427 * Keep track of how many times we encountered a full subbuffer, to aid
428 * the user space app in telling how many lost events there were.
429 */
430static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
431 void *prev_subbuf, size_t prev_padding)
432{
433 struct blk_trace *bt;
434
435 if (!relay_buf_full(buf))
436 return 1;
437
438 bt = buf->chan->private_data;
439 atomic_inc(&bt->dropped);
440 return 0;
441}
442
443static int blk_remove_buf_file_callback(struct dentry *dentry)
444{
445 debugfs_remove(dentry);
446
447 return 0;
448}
449
450static struct dentry *blk_create_buf_file_callback(const char *filename,
451 struct dentry *parent,
452 umode_t mode,
453 struct rchan_buf *buf,
454 int *is_global)
455{
456 return debugfs_create_file(filename, mode, parent, buf,
457 &relay_file_operations);
458}
459
460static struct rchan_callbacks blk_relay_callbacks = {
461 .subbuf_start = blk_subbuf_start_callback,
462 .create_buf_file = blk_create_buf_file_callback,
463 .remove_buf_file = blk_remove_buf_file_callback,
464};
465
466static void blk_trace_setup_lba(struct blk_trace *bt,
467 struct block_device *bdev)
468{
469 struct hd_struct *part = NULL;
470
471 if (bdev)
472 part = bdev->bd_part;
473
474 if (part) {
475 bt->start_lba = part->start_sect;
476 bt->end_lba = part->start_sect + part->nr_sects;
477 } else {
478 bt->start_lba = 0;
479 bt->end_lba = -1ULL;
480 }
481}
482
483/*
484 * Setup everything required to start tracing
485 */
486static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
487 struct block_device *bdev,
488 struct blk_user_trace_setup *buts)
489{
490 struct blk_trace *bt = NULL;
491 struct dentry *dir = NULL;
492 int ret;
493
494 if (!buts->buf_size || !buts->buf_nr)
495 return -EINVAL;
496
497 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
498 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
499
500 /*
501 * some device names have larger paths - convert the slashes
502 * to underscores for this to work as expected
503 */
504 strreplace(buts->name, '/', '_');
505
506 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
507 if (!bt)
508 return -ENOMEM;
509
510 ret = -ENOMEM;
511 bt->sequence = alloc_percpu(unsigned long);
512 if (!bt->sequence)
513 goto err;
514
515 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
516 if (!bt->msg_data)
517 goto err;
518
519 ret = -ENOENT;
520
521 if (!blk_debugfs_root)
522 goto err;
523
524 dir = debugfs_lookup(buts->name, blk_debugfs_root);
525 if (!dir)
526 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
527 if (!dir)
528 goto err;
529
530 bt->dev = dev;
531 atomic_set(&bt->dropped, 0);
532 INIT_LIST_HEAD(&bt->running_list);
533
534 ret = -EIO;
535 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
536 &blk_dropped_fops);
537 if (!bt->dropped_file)
538 goto err;
539
540 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
541 if (!bt->msg_file)
542 goto err;
543
544 bt->rchan = relay_open("trace", dir, buts->buf_size,
545 buts->buf_nr, &blk_relay_callbacks, bt);
546 if (!bt->rchan)
547 goto err;
548
549 bt->act_mask = buts->act_mask;
550 if (!bt->act_mask)
551 bt->act_mask = (u16) -1;
552
553 blk_trace_setup_lba(bt, bdev);
554
555 /* overwrite with user settings */
556 if (buts->start_lba)
557 bt->start_lba = buts->start_lba;
558 if (buts->end_lba)
559 bt->end_lba = buts->end_lba;
560
561 bt->pid = buts->pid;
562 bt->trace_state = Blktrace_setup;
563
564 ret = -EBUSY;
565 if (cmpxchg(&q->blk_trace, NULL, bt))
566 goto err;
567
568 get_probe_ref();
569
570 ret = 0;
571err:
572 if (dir && !bt->dir)
573 dput(dir);
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->blk_trace_mutex);
607 ret = __blk_trace_setup(q, name, dev, bdev, arg);
608 mutex_unlock(&q->blk_trace_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 = q->blk_trace;
652
653 if (bt == NULL)
654 return -EINVAL;
655
656 /*
657 * For starting a trace, we can transition from a setup or stopped
658 * trace. For stopping a trace, the state must be running
659 */
660 ret = -EINVAL;
661 if (start) {
662 if (bt->trace_state == Blktrace_setup ||
663 bt->trace_state == Blktrace_stopped) {
664 blktrace_seq++;
665 smp_mb();
666 bt->trace_state = Blktrace_running;
667 spin_lock_irq(&running_trace_lock);
668 list_add(&bt->running_list, &running_trace_list);
669 spin_unlock_irq(&running_trace_lock);
670
671 trace_note_time(bt);
672 ret = 0;
673 }
674 } else {
675 if (bt->trace_state == Blktrace_running) {
676 bt->trace_state = Blktrace_stopped;
677 spin_lock_irq(&running_trace_lock);
678 list_del_init(&bt->running_list);
679 spin_unlock_irq(&running_trace_lock);
680 relay_flush(bt->rchan);
681 ret = 0;
682 }
683 }
684
685 return ret;
686}
687
688int blk_trace_startstop(struct request_queue *q, int start)
689{
690 int ret;
691
692 mutex_lock(&q->blk_trace_mutex);
693 ret = __blk_trace_startstop(q, start);
694 mutex_unlock(&q->blk_trace_mutex);
695
696 return ret;
697}
698EXPORT_SYMBOL_GPL(blk_trace_startstop);
699
700/*
701 * When reading or writing the blktrace sysfs files, the references to the
702 * opened sysfs or device files should prevent the underlying block device
703 * from being removed. So no further delete protection is really needed.
704 */
705
706/**
707 * blk_trace_ioctl: - handle the ioctls associated with tracing
708 * @bdev: the block device
709 * @cmd: the ioctl cmd
710 * @arg: the argument data, if any
711 *
712 **/
713int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
714{
715 struct request_queue *q;
716 int ret, start = 0;
717 char b[BDEVNAME_SIZE];
718
719 q = bdev_get_queue(bdev);
720 if (!q)
721 return -ENXIO;
722
723 mutex_lock(&q->blk_trace_mutex);
724
725 switch (cmd) {
726 case BLKTRACESETUP:
727 bdevname(bdev, b);
728 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
729 break;
730#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
731 case BLKTRACESETUP32:
732 bdevname(bdev, b);
733 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
734 break;
735#endif
736 case BLKTRACESTART:
737 start = 1;
738 case BLKTRACESTOP:
739 ret = __blk_trace_startstop(q, start);
740 break;
741 case BLKTRACETEARDOWN:
742 ret = __blk_trace_remove(q);
743 break;
744 default:
745 ret = -ENOTTY;
746 break;
747 }
748
749 mutex_unlock(&q->blk_trace_mutex);
750 return ret;
751}
752
753/**
754 * blk_trace_shutdown: - stop and cleanup trace structures
755 * @q: the request queue associated with the device
756 *
757 **/
758void blk_trace_shutdown(struct request_queue *q)
759{
760 mutex_lock(&q->blk_trace_mutex);
761
762 if (q->blk_trace) {
763 __blk_trace_startstop(q, 0);
764 __blk_trace_remove(q);
765 }
766
767 mutex_unlock(&q->blk_trace_mutex);
768}
769
770#ifdef CONFIG_BLK_CGROUP
771static union kernfs_node_id *
772blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
773{
774 struct blk_trace *bt = q->blk_trace;
775
776 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
777 return NULL;
778
779 if (!bio->bi_css)
780 return NULL;
781 return cgroup_get_kernfs_id(bio->bi_css->cgroup);
782}
783#else
784static union kernfs_node_id *
785blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
786{
787 return NULL;
788}
789#endif
790
791static union kernfs_node_id *
792blk_trace_request_get_cgid(struct request_queue *q, struct request *rq)
793{
794 if (!rq->bio)
795 return NULL;
796 /* Use the first bio */
797 return blk_trace_bio_get_cgid(q, rq->bio);
798}
799
800/*
801 * blktrace probes
802 */
803
804/**
805 * blk_add_trace_rq - Add a trace for a request oriented action
806 * @rq: the source request
807 * @error: return status to log
808 * @nr_bytes: number of completed bytes
809 * @what: the action
810 * @cgid: the cgroup info
811 *
812 * Description:
813 * Records an action against a request. Will log the bio offset + size.
814 *
815 **/
816static void blk_add_trace_rq(struct request *rq, int error,
817 unsigned int nr_bytes, u32 what,
818 union kernfs_node_id *cgid)
819{
820 struct blk_trace *bt = rq->q->blk_trace;
821
822 if (likely(!bt))
823 return;
824
825 if (blk_rq_is_passthrough(rq))
826 what |= BLK_TC_ACT(BLK_TC_PC);
827 else
828 what |= BLK_TC_ACT(BLK_TC_FS);
829
830 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
831 rq->cmd_flags, what, error, 0, NULL, cgid);
832}
833
834static void blk_add_trace_rq_insert(void *ignore,
835 struct request_queue *q, struct request *rq)
836{
837 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
838 blk_trace_request_get_cgid(q, rq));
839}
840
841static void blk_add_trace_rq_issue(void *ignore,
842 struct request_queue *q, struct request *rq)
843{
844 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
845 blk_trace_request_get_cgid(q, rq));
846}
847
848static void blk_add_trace_rq_requeue(void *ignore,
849 struct request_queue *q,
850 struct request *rq)
851{
852 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
853 blk_trace_request_get_cgid(q, rq));
854}
855
856static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
857 int error, unsigned int nr_bytes)
858{
859 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
860 blk_trace_request_get_cgid(rq->q, rq));
861}
862
863/**
864 * blk_add_trace_bio - Add a trace for a bio oriented action
865 * @q: queue the io is for
866 * @bio: the source bio
867 * @what: the action
868 * @error: error, if any
869 *
870 * Description:
871 * Records an action against a bio. Will log the bio offset + size.
872 *
873 **/
874static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
875 u32 what, int error)
876{
877 struct blk_trace *bt = q->blk_trace;
878
879 if (likely(!bt))
880 return;
881
882 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
883 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
884 blk_trace_bio_get_cgid(q, bio));
885}
886
887static void blk_add_trace_bio_bounce(void *ignore,
888 struct request_queue *q, struct bio *bio)
889{
890 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
891}
892
893static void blk_add_trace_bio_complete(void *ignore,
894 struct request_queue *q, struct bio *bio,
895 int error)
896{
897 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
898}
899
900static void blk_add_trace_bio_backmerge(void *ignore,
901 struct request_queue *q,
902 struct request *rq,
903 struct bio *bio)
904{
905 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
906}
907
908static void blk_add_trace_bio_frontmerge(void *ignore,
909 struct request_queue *q,
910 struct request *rq,
911 struct bio *bio)
912{
913 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
914}
915
916static void blk_add_trace_bio_queue(void *ignore,
917 struct request_queue *q, struct bio *bio)
918{
919 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
920}
921
922static void blk_add_trace_getrq(void *ignore,
923 struct request_queue *q,
924 struct bio *bio, int rw)
925{
926 if (bio)
927 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
928 else {
929 struct blk_trace *bt = q->blk_trace;
930
931 if (bt)
932 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
933 NULL, NULL);
934 }
935}
936
937
938static void blk_add_trace_sleeprq(void *ignore,
939 struct request_queue *q,
940 struct bio *bio, int rw)
941{
942 if (bio)
943 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
944 else {
945 struct blk_trace *bt = q->blk_trace;
946
947 if (bt)
948 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
949 0, 0, NULL, NULL);
950 }
951}
952
953static void blk_add_trace_plug(void *ignore, struct request_queue *q)
954{
955 struct blk_trace *bt = q->blk_trace;
956
957 if (bt)
958 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, NULL);
959}
960
961static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
962 unsigned int depth, bool explicit)
963{
964 struct blk_trace *bt = q->blk_trace;
965
966 if (bt) {
967 __be64 rpdu = cpu_to_be64(depth);
968 u32 what;
969
970 if (explicit)
971 what = BLK_TA_UNPLUG_IO;
972 else
973 what = BLK_TA_UNPLUG_TIMER;
974
975 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, NULL);
976 }
977}
978
979static void blk_add_trace_split(void *ignore,
980 struct request_queue *q, struct bio *bio,
981 unsigned int pdu)
982{
983 struct blk_trace *bt = q->blk_trace;
984
985 if (bt) {
986 __be64 rpdu = cpu_to_be64(pdu);
987
988 __blk_add_trace(bt, bio->bi_iter.bi_sector,
989 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
990 BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu),
991 &rpdu, blk_trace_bio_get_cgid(q, bio));
992 }
993}
994
995/**
996 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
997 * @ignore: trace callback data parameter (not used)
998 * @q: queue the io is for
999 * @bio: the source bio
1000 * @dev: target device
1001 * @from: source sector
1002 *
1003 * Description:
1004 * Device mapper or raid target sometimes need to split a bio because
1005 * it spans a stripe (or similar). Add a trace for that action.
1006 *
1007 **/
1008static void blk_add_trace_bio_remap(void *ignore,
1009 struct request_queue *q, struct bio *bio,
1010 dev_t dev, sector_t from)
1011{
1012 struct blk_trace *bt = q->blk_trace;
1013 struct blk_io_trace_remap r;
1014
1015 if (likely(!bt))
1016 return;
1017
1018 r.device_from = cpu_to_be32(dev);
1019 r.device_to = cpu_to_be32(bio_dev(bio));
1020 r.sector_from = cpu_to_be64(from);
1021
1022 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1023 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status,
1024 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1025}
1026
1027/**
1028 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1029 * @ignore: trace callback data parameter (not used)
1030 * @q: queue the io is for
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,
1041 struct request_queue *q,
1042 struct request *rq, dev_t dev,
1043 sector_t from)
1044{
1045 struct blk_trace *bt = q->blk_trace;
1046 struct blk_io_trace_remap r;
1047
1048 if (likely(!bt))
1049 return;
1050
1051 r.device_from = cpu_to_be32(dev);
1052 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1053 r.sector_from = cpu_to_be64(from);
1054
1055 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1056 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1057 sizeof(r), &r, blk_trace_request_get_cgid(q, rq));
1058}
1059
1060/**
1061 * blk_add_driver_data - Add binary message with driver-specific data
1062 * @q: queue the io is for
1063 * @rq: io request
1064 * @data: driver-specific data
1065 * @len: length of driver-specific data
1066 *
1067 * Description:
1068 * Some drivers might want to write driver-specific data per request.
1069 *
1070 **/
1071void blk_add_driver_data(struct request_queue *q,
1072 struct request *rq,
1073 void *data, size_t len)
1074{
1075 struct blk_trace *bt = q->blk_trace;
1076
1077 if (likely(!bt))
1078 return;
1079
1080 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1081 BLK_TA_DRV_DATA, 0, len, data,
1082 blk_trace_request_get_cgid(q, rq));
1083}
1084EXPORT_SYMBOL_GPL(blk_add_driver_data);
1085
1086static void blk_register_tracepoints(void)
1087{
1088 int ret;
1089
1090 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1091 WARN_ON(ret);
1092 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, 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_sleeprq(blk_add_trace_sleeprq, NULL);
1111 WARN_ON(ret);
1112 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1113 WARN_ON(ret);
1114 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1115 WARN_ON(ret);
1116 ret = register_trace_block_split(blk_add_trace_split, NULL);
1117 WARN_ON(ret);
1118 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1119 WARN_ON(ret);
1120 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1121 WARN_ON(ret);
1122}
1123
1124static void blk_unregister_tracepoints(void)
1125{
1126 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1127 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1128 unregister_trace_block_split(blk_add_trace_split, NULL);
1129 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1130 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1131 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1132 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1133 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1134 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1135 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1136 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1137 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1138 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1139 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1140 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1141 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1142
1143 tracepoint_synchronize_unregister();
1144}
1145
1146/*
1147 * struct blk_io_tracer formatting routines
1148 */
1149
1150static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1151{
1152 int i = 0;
1153 int tc = t->action >> BLK_TC_SHIFT;
1154
1155 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1156 rwbs[i++] = 'N';
1157 goto out;
1158 }
1159
1160 if (tc & BLK_TC_FLUSH)
1161 rwbs[i++] = 'F';
1162
1163 if (tc & BLK_TC_DISCARD)
1164 rwbs[i++] = 'D';
1165 else if (tc & BLK_TC_WRITE)
1166 rwbs[i++] = 'W';
1167 else if (t->bytes)
1168 rwbs[i++] = 'R';
1169 else
1170 rwbs[i++] = 'N';
1171
1172 if (tc & BLK_TC_FUA)
1173 rwbs[i++] = 'F';
1174 if (tc & BLK_TC_AHEAD)
1175 rwbs[i++] = 'A';
1176 if (tc & BLK_TC_SYNC)
1177 rwbs[i++] = 'S';
1178 if (tc & BLK_TC_META)
1179 rwbs[i++] = 'M';
1180out:
1181 rwbs[i] = '\0';
1182}
1183
1184static inline
1185const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1186{
1187 return (const struct blk_io_trace *)ent;
1188}
1189
1190static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1191{
1192 return (void *)(te_blk_io_trace(ent) + 1) +
1193 (has_cg ? sizeof(union kernfs_node_id) : 0);
1194}
1195
1196static inline const void *cgid_start(const struct trace_entry *ent)
1197{
1198 return (void *)(te_blk_io_trace(ent) + 1);
1199}
1200
1201static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1202{
1203 return te_blk_io_trace(ent)->pdu_len -
1204 (has_cg ? sizeof(union kernfs_node_id) : 0);
1205}
1206
1207static inline u32 t_action(const struct trace_entry *ent)
1208{
1209 return te_blk_io_trace(ent)->action;
1210}
1211
1212static inline u32 t_bytes(const struct trace_entry *ent)
1213{
1214 return te_blk_io_trace(ent)->bytes;
1215}
1216
1217static inline u32 t_sec(const struct trace_entry *ent)
1218{
1219 return te_blk_io_trace(ent)->bytes >> 9;
1220}
1221
1222static inline unsigned long long t_sector(const struct trace_entry *ent)
1223{
1224 return te_blk_io_trace(ent)->sector;
1225}
1226
1227static inline __u16 t_error(const struct trace_entry *ent)
1228{
1229 return te_blk_io_trace(ent)->error;
1230}
1231
1232static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1233{
1234 const __u64 *val = pdu_start(ent, has_cg);
1235 return be64_to_cpu(*val);
1236}
1237
1238static void get_pdu_remap(const struct trace_entry *ent,
1239 struct blk_io_trace_remap *r, bool has_cg)
1240{
1241 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1242 __u64 sector_from = __r->sector_from;
1243
1244 r->device_from = be32_to_cpu(__r->device_from);
1245 r->device_to = be32_to_cpu(__r->device_to);
1246 r->sector_from = be64_to_cpu(sector_from);
1247}
1248
1249typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1250 bool has_cg);
1251
1252static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1253 bool has_cg)
1254{
1255 char rwbs[RWBS_LEN];
1256 unsigned long long ts = iter->ts;
1257 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1258 unsigned secs = (unsigned long)ts;
1259 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1260
1261 fill_rwbs(rwbs, t);
1262
1263 trace_seq_printf(&iter->seq,
1264 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1265 MAJOR(t->device), MINOR(t->device), iter->cpu,
1266 secs, nsec_rem, iter->ent->pid, act, rwbs);
1267}
1268
1269static void blk_log_action(struct trace_iterator *iter, const char *act,
1270 bool has_cg)
1271{
1272 char rwbs[RWBS_LEN];
1273 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1274
1275 fill_rwbs(rwbs, t);
1276 if (has_cg) {
1277 const union kernfs_node_id *id = cgid_start(iter->ent);
1278
1279 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1280 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1281
1282 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1283 sizeof(blkcg_name_buf));
1284 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1285 MAJOR(t->device), MINOR(t->device),
1286 blkcg_name_buf, act, rwbs);
1287 } else
1288 trace_seq_printf(&iter->seq,
1289 "%3d,%-3d %x,%-x %2s %3s ",
1290 MAJOR(t->device), MINOR(t->device),
1291 id->ino, id->generation, act, rwbs);
1292 } else
1293 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1294 MAJOR(t->device), MINOR(t->device), act, rwbs);
1295}
1296
1297static void blk_log_dump_pdu(struct trace_seq *s,
1298 const struct trace_entry *ent, bool has_cg)
1299{
1300 const unsigned char *pdu_buf;
1301 int pdu_len;
1302 int i, end;
1303
1304 pdu_buf = pdu_start(ent, has_cg);
1305 pdu_len = pdu_real_len(ent, has_cg);
1306
1307 if (!pdu_len)
1308 return;
1309
1310 /* find the last zero that needs to be printed */
1311 for (end = pdu_len - 1; end >= 0; end--)
1312 if (pdu_buf[end])
1313 break;
1314 end++;
1315
1316 trace_seq_putc(s, '(');
1317
1318 for (i = 0; i < pdu_len; i++) {
1319
1320 trace_seq_printf(s, "%s%02x",
1321 i == 0 ? "" : " ", pdu_buf[i]);
1322
1323 /*
1324 * stop when the rest is just zeroes and indicate so
1325 * with a ".." appended
1326 */
1327 if (i == end && end != pdu_len - 1) {
1328 trace_seq_puts(s, " ..) ");
1329 return;
1330 }
1331 }
1332
1333 trace_seq_puts(s, ") ");
1334}
1335
1336static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1337{
1338 char cmd[TASK_COMM_LEN];
1339
1340 trace_find_cmdline(ent->pid, cmd);
1341
1342 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1343 trace_seq_printf(s, "%u ", t_bytes(ent));
1344 blk_log_dump_pdu(s, ent, has_cg);
1345 trace_seq_printf(s, "[%s]\n", cmd);
1346 } else {
1347 if (t_sec(ent))
1348 trace_seq_printf(s, "%llu + %u [%s]\n",
1349 t_sector(ent), t_sec(ent), cmd);
1350 else
1351 trace_seq_printf(s, "[%s]\n", cmd);
1352 }
1353}
1354
1355static void blk_log_with_error(struct trace_seq *s,
1356 const struct trace_entry *ent, bool has_cg)
1357{
1358 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1359 blk_log_dump_pdu(s, ent, has_cg);
1360 trace_seq_printf(s, "[%d]\n", t_error(ent));
1361 } else {
1362 if (t_sec(ent))
1363 trace_seq_printf(s, "%llu + %u [%d]\n",
1364 t_sector(ent),
1365 t_sec(ent), t_error(ent));
1366 else
1367 trace_seq_printf(s, "%llu [%d]\n",
1368 t_sector(ent), t_error(ent));
1369 }
1370}
1371
1372static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1373{
1374 struct blk_io_trace_remap r = { .device_from = 0, };
1375
1376 get_pdu_remap(ent, &r, has_cg);
1377 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1378 t_sector(ent), t_sec(ent),
1379 MAJOR(r.device_from), MINOR(r.device_from),
1380 (unsigned long long)r.sector_from);
1381}
1382
1383static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1384{
1385 char cmd[TASK_COMM_LEN];
1386
1387 trace_find_cmdline(ent->pid, cmd);
1388
1389 trace_seq_printf(s, "[%s]\n", cmd);
1390}
1391
1392static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1393{
1394 char cmd[TASK_COMM_LEN];
1395
1396 trace_find_cmdline(ent->pid, cmd);
1397
1398 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1399}
1400
1401static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1402{
1403 char cmd[TASK_COMM_LEN];
1404
1405 trace_find_cmdline(ent->pid, cmd);
1406
1407 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1408 get_pdu_int(ent, has_cg), cmd);
1409}
1410
1411static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1412 bool has_cg)
1413{
1414
1415 trace_seq_putmem(s, pdu_start(ent, has_cg),
1416 pdu_real_len(ent, has_cg));
1417 trace_seq_putc(s, '\n');
1418}
1419
1420/*
1421 * struct tracer operations
1422 */
1423
1424static void blk_tracer_print_header(struct seq_file *m)
1425{
1426 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1427 return;
1428 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1429 "# | | | | | |\n");
1430}
1431
1432static void blk_tracer_start(struct trace_array *tr)
1433{
1434 blk_tracer_enabled = true;
1435}
1436
1437static int blk_tracer_init(struct trace_array *tr)
1438{
1439 blk_tr = tr;
1440 blk_tracer_start(tr);
1441 return 0;
1442}
1443
1444static void blk_tracer_stop(struct trace_array *tr)
1445{
1446 blk_tracer_enabled = false;
1447}
1448
1449static void blk_tracer_reset(struct trace_array *tr)
1450{
1451 blk_tracer_stop(tr);
1452}
1453
1454static const struct {
1455 const char *act[2];
1456 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1457 bool has_cg);
1458} what2act[] = {
1459 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1460 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1461 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1462 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1463 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1464 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1465 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1466 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1467 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1468 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1469 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1470 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1471 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1472 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1473 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1474};
1475
1476static enum print_line_t print_one_line(struct trace_iterator *iter,
1477 bool classic)
1478{
1479 struct trace_array *tr = iter->tr;
1480 struct trace_seq *s = &iter->seq;
1481 const struct blk_io_trace *t;
1482 u16 what;
1483 bool long_act;
1484 blk_log_action_t *log_action;
1485 bool has_cg;
1486
1487 t = te_blk_io_trace(iter->ent);
1488 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1489 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1490 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1491 has_cg = t->action & __BLK_TA_CGROUP;
1492
1493 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1494 log_action(iter, long_act ? "message" : "m", has_cg);
1495 blk_log_msg(s, iter->ent, has_cg);
1496 return trace_handle_return(s);
1497 }
1498
1499 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1500 trace_seq_printf(s, "Unknown action %x\n", what);
1501 else {
1502 log_action(iter, what2act[what].act[long_act], has_cg);
1503 what2act[what].print(s, iter->ent, has_cg);
1504 }
1505
1506 return trace_handle_return(s);
1507}
1508
1509static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1510 int flags, struct trace_event *event)
1511{
1512 return print_one_line(iter, false);
1513}
1514
1515static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1516{
1517 struct trace_seq *s = &iter->seq;
1518 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1519 const int offset = offsetof(struct blk_io_trace, sector);
1520 struct blk_io_trace old = {
1521 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1522 .time = iter->ts,
1523 };
1524
1525 trace_seq_putmem(s, &old, offset);
1526 trace_seq_putmem(s, &t->sector,
1527 sizeof(old) - offset + t->pdu_len);
1528}
1529
1530static enum print_line_t
1531blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1532 struct trace_event *event)
1533{
1534 blk_trace_synthesize_old_trace(iter);
1535
1536 return trace_handle_return(&iter->seq);
1537}
1538
1539static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1540{
1541 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1542 return TRACE_TYPE_UNHANDLED;
1543
1544 return print_one_line(iter, true);
1545}
1546
1547static int
1548blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1549{
1550 /* don't output context-info for blk_classic output */
1551 if (bit == TRACE_BLK_OPT_CLASSIC) {
1552 if (set)
1553 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1554 else
1555 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1556 }
1557 return 0;
1558}
1559
1560static struct tracer blk_tracer __read_mostly = {
1561 .name = "blk",
1562 .init = blk_tracer_init,
1563 .reset = blk_tracer_reset,
1564 .start = blk_tracer_start,
1565 .stop = blk_tracer_stop,
1566 .print_header = blk_tracer_print_header,
1567 .print_line = blk_tracer_print_line,
1568 .flags = &blk_tracer_flags,
1569 .set_flag = blk_tracer_set_flag,
1570};
1571
1572static struct trace_event_functions trace_blk_event_funcs = {
1573 .trace = blk_trace_event_print,
1574 .binary = blk_trace_event_print_binary,
1575};
1576
1577static struct trace_event trace_blk_event = {
1578 .type = TRACE_BLK,
1579 .funcs = &trace_blk_event_funcs,
1580};
1581
1582static int __init init_blk_tracer(void)
1583{
1584 if (!register_trace_event(&trace_blk_event)) {
1585 pr_warn("Warning: could not register block events\n");
1586 return 1;
1587 }
1588
1589 if (register_tracer(&blk_tracer) != 0) {
1590 pr_warn("Warning: could not register the block tracer\n");
1591 unregister_trace_event(&trace_blk_event);
1592 return 1;
1593 }
1594
1595 return 0;
1596}
1597
1598device_initcall(init_blk_tracer);
1599
1600static int blk_trace_remove_queue(struct request_queue *q)
1601{
1602 struct blk_trace *bt;
1603
1604 bt = xchg(&q->blk_trace, NULL);
1605 if (bt == NULL)
1606 return -EINVAL;
1607
1608 put_probe_ref();
1609 blk_trace_free(bt);
1610 return 0;
1611}
1612
1613/*
1614 * Setup everything required to start tracing
1615 */
1616static int blk_trace_setup_queue(struct request_queue *q,
1617 struct block_device *bdev)
1618{
1619 struct blk_trace *bt = NULL;
1620 int ret = -ENOMEM;
1621
1622 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1623 if (!bt)
1624 return -ENOMEM;
1625
1626 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1627 if (!bt->msg_data)
1628 goto free_bt;
1629
1630 bt->dev = bdev->bd_dev;
1631 bt->act_mask = (u16)-1;
1632
1633 blk_trace_setup_lba(bt, bdev);
1634
1635 ret = -EBUSY;
1636 if (cmpxchg(&q->blk_trace, NULL, bt))
1637 goto free_bt;
1638
1639 get_probe_ref();
1640 return 0;
1641
1642free_bt:
1643 blk_trace_free(bt);
1644 return ret;
1645}
1646
1647/*
1648 * sysfs interface to enable and configure tracing
1649 */
1650
1651static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1652 struct device_attribute *attr,
1653 char *buf);
1654static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1655 struct device_attribute *attr,
1656 const char *buf, size_t count);
1657#define BLK_TRACE_DEVICE_ATTR(_name) \
1658 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1659 sysfs_blk_trace_attr_show, \
1660 sysfs_blk_trace_attr_store)
1661
1662static BLK_TRACE_DEVICE_ATTR(enable);
1663static BLK_TRACE_DEVICE_ATTR(act_mask);
1664static BLK_TRACE_DEVICE_ATTR(pid);
1665static BLK_TRACE_DEVICE_ATTR(start_lba);
1666static BLK_TRACE_DEVICE_ATTR(end_lba);
1667
1668static struct attribute *blk_trace_attrs[] = {
1669 &dev_attr_enable.attr,
1670 &dev_attr_act_mask.attr,
1671 &dev_attr_pid.attr,
1672 &dev_attr_start_lba.attr,
1673 &dev_attr_end_lba.attr,
1674 NULL
1675};
1676
1677struct attribute_group blk_trace_attr_group = {
1678 .name = "trace",
1679 .attrs = blk_trace_attrs,
1680};
1681
1682static const struct {
1683 int mask;
1684 const char *str;
1685} mask_maps[] = {
1686 { BLK_TC_READ, "read" },
1687 { BLK_TC_WRITE, "write" },
1688 { BLK_TC_FLUSH, "flush" },
1689 { BLK_TC_SYNC, "sync" },
1690 { BLK_TC_QUEUE, "queue" },
1691 { BLK_TC_REQUEUE, "requeue" },
1692 { BLK_TC_ISSUE, "issue" },
1693 { BLK_TC_COMPLETE, "complete" },
1694 { BLK_TC_FS, "fs" },
1695 { BLK_TC_PC, "pc" },
1696 { BLK_TC_NOTIFY, "notify" },
1697 { BLK_TC_AHEAD, "ahead" },
1698 { BLK_TC_META, "meta" },
1699 { BLK_TC_DISCARD, "discard" },
1700 { BLK_TC_DRV_DATA, "drv_data" },
1701 { BLK_TC_FUA, "fua" },
1702};
1703
1704static int blk_trace_str2mask(const char *str)
1705{
1706 int i;
1707 int mask = 0;
1708 char *buf, *s, *token;
1709
1710 buf = kstrdup(str, GFP_KERNEL);
1711 if (buf == NULL)
1712 return -ENOMEM;
1713 s = strstrip(buf);
1714
1715 while (1) {
1716 token = strsep(&s, ",");
1717 if (token == NULL)
1718 break;
1719
1720 if (*token == '\0')
1721 continue;
1722
1723 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1724 if (strcasecmp(token, mask_maps[i].str) == 0) {
1725 mask |= mask_maps[i].mask;
1726 break;
1727 }
1728 }
1729 if (i == ARRAY_SIZE(mask_maps)) {
1730 mask = -EINVAL;
1731 break;
1732 }
1733 }
1734 kfree(buf);
1735
1736 return mask;
1737}
1738
1739static ssize_t blk_trace_mask2str(char *buf, int mask)
1740{
1741 int i;
1742 char *p = buf;
1743
1744 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1745 if (mask & mask_maps[i].mask) {
1746 p += sprintf(p, "%s%s",
1747 (p == buf) ? "" : ",", mask_maps[i].str);
1748 }
1749 }
1750 *p++ = '\n';
1751
1752 return p - buf;
1753}
1754
1755static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1756{
1757 if (bdev->bd_disk == NULL)
1758 return NULL;
1759
1760 return bdev_get_queue(bdev);
1761}
1762
1763static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1764 struct device_attribute *attr,
1765 char *buf)
1766{
1767 struct hd_struct *p = dev_to_part(dev);
1768 struct request_queue *q;
1769 struct block_device *bdev;
1770 ssize_t ret = -ENXIO;
1771
1772 bdev = bdget(part_devt(p));
1773 if (bdev == NULL)
1774 goto out;
1775
1776 q = blk_trace_get_queue(bdev);
1777 if (q == NULL)
1778 goto out_bdput;
1779
1780 mutex_lock(&q->blk_trace_mutex);
1781
1782 if (attr == &dev_attr_enable) {
1783 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1784 goto out_unlock_bdev;
1785 }
1786
1787 if (q->blk_trace == NULL)
1788 ret = sprintf(buf, "disabled\n");
1789 else if (attr == &dev_attr_act_mask)
1790 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1791 else if (attr == &dev_attr_pid)
1792 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1793 else if (attr == &dev_attr_start_lba)
1794 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1795 else if (attr == &dev_attr_end_lba)
1796 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1797
1798out_unlock_bdev:
1799 mutex_unlock(&q->blk_trace_mutex);
1800out_bdput:
1801 bdput(bdev);
1802out:
1803 return ret;
1804}
1805
1806static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1807 struct device_attribute *attr,
1808 const char *buf, size_t count)
1809{
1810 struct block_device *bdev;
1811 struct request_queue *q;
1812 struct hd_struct *p;
1813 u64 value;
1814 ssize_t ret = -EINVAL;
1815
1816 if (count == 0)
1817 goto out;
1818
1819 if (attr == &dev_attr_act_mask) {
1820 if (kstrtoull(buf, 0, &value)) {
1821 /* Assume it is a list of trace category names */
1822 ret = blk_trace_str2mask(buf);
1823 if (ret < 0)
1824 goto out;
1825 value = ret;
1826 }
1827 } else if (kstrtoull(buf, 0, &value))
1828 goto out;
1829
1830 ret = -ENXIO;
1831
1832 p = dev_to_part(dev);
1833 bdev = bdget(part_devt(p));
1834 if (bdev == NULL)
1835 goto out;
1836
1837 q = blk_trace_get_queue(bdev);
1838 if (q == NULL)
1839 goto out_bdput;
1840
1841 mutex_lock(&q->blk_trace_mutex);
1842
1843 if (attr == &dev_attr_enable) {
1844 if (value)
1845 ret = blk_trace_setup_queue(q, bdev);
1846 else
1847 ret = blk_trace_remove_queue(q);
1848 goto out_unlock_bdev;
1849 }
1850
1851 ret = 0;
1852 if (q->blk_trace == NULL)
1853 ret = blk_trace_setup_queue(q, bdev);
1854
1855 if (ret == 0) {
1856 if (attr == &dev_attr_act_mask)
1857 q->blk_trace->act_mask = value;
1858 else if (attr == &dev_attr_pid)
1859 q->blk_trace->pid = value;
1860 else if (attr == &dev_attr_start_lba)
1861 q->blk_trace->start_lba = value;
1862 else if (attr == &dev_attr_end_lba)
1863 q->blk_trace->end_lba = value;
1864 }
1865
1866out_unlock_bdev:
1867 mutex_unlock(&q->blk_trace_mutex);
1868out_bdput:
1869 bdput(bdev);
1870out:
1871 return ret ? ret : count;
1872}
1873
1874int blk_trace_init_sysfs(struct device *dev)
1875{
1876 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1877}
1878
1879void blk_trace_remove_sysfs(struct device *dev)
1880{
1881 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1882}
1883
1884#endif /* CONFIG_BLK_DEV_IO_TRACE */
1885
1886#ifdef CONFIG_EVENT_TRACING
1887
1888void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
1889{
1890 int i = 0;
1891
1892 if (op & REQ_PREFLUSH)
1893 rwbs[i++] = 'F';
1894
1895 switch (op & REQ_OP_MASK) {
1896 case REQ_OP_WRITE:
1897 case REQ_OP_WRITE_SAME:
1898 rwbs[i++] = 'W';
1899 break;
1900 case REQ_OP_DISCARD:
1901 rwbs[i++] = 'D';
1902 break;
1903 case REQ_OP_SECURE_ERASE:
1904 rwbs[i++] = 'D';
1905 rwbs[i++] = 'E';
1906 break;
1907 case REQ_OP_FLUSH:
1908 rwbs[i++] = 'F';
1909 break;
1910 case REQ_OP_READ:
1911 rwbs[i++] = 'R';
1912 break;
1913 default:
1914 rwbs[i++] = 'N';
1915 }
1916
1917 if (op & REQ_FUA)
1918 rwbs[i++] = 'F';
1919 if (op & REQ_RAHEAD)
1920 rwbs[i++] = 'A';
1921 if (op & REQ_SYNC)
1922 rwbs[i++] = 'S';
1923 if (op & REQ_META)
1924 rwbs[i++] = 'M';
1925
1926 rwbs[i] = '\0';
1927}
1928EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1929
1930#endif /* CONFIG_EVENT_TRACING */
1931
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
4 *
5 */
6#include <linux/kernel.h>
7#include <linux/blkdev.h>
8#include <linux/blktrace_api.h>
9#include <linux/percpu.h>
10#include <linux/init.h>
11#include <linux/mutex.h>
12#include <linux/slab.h>
13#include <linux/debugfs.h>
14#include <linux/export.h>
15#include <linux/time.h>
16#include <linux/uaccess.h>
17#include <linux/list.h>
18#include <linux/blk-cgroup.h>
19
20#include "../../block/blk.h"
21
22#include <trace/events/block.h>
23
24#include "trace_output.h"
25
26#ifdef CONFIG_BLK_DEV_IO_TRACE
27
28static unsigned int blktrace_seq __read_mostly = 1;
29
30static struct trace_array *blk_tr;
31static bool blk_tracer_enabled __read_mostly;
32
33static LIST_HEAD(running_trace_list);
34static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
35
36/* Select an alternative, minimalistic output than the original one */
37#define TRACE_BLK_OPT_CLASSIC 0x1
38#define TRACE_BLK_OPT_CGROUP 0x2
39#define TRACE_BLK_OPT_CGNAME 0x4
40
41static struct tracer_opt blk_tracer_opts[] = {
42 /* Default disable the minimalistic output */
43 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
44#ifdef CONFIG_BLK_CGROUP
45 { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
46 { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
47#endif
48 { }
49};
50
51static struct tracer_flags blk_tracer_flags = {
52 .val = 0,
53 .opts = blk_tracer_opts,
54};
55
56/* Global reference count of probes */
57static DEFINE_MUTEX(blk_probe_mutex);
58static int blk_probes_ref;
59
60static void blk_register_tracepoints(void);
61static void blk_unregister_tracepoints(void);
62
63/*
64 * Send out a notify message.
65 */
66static void trace_note(struct blk_trace *bt, pid_t pid, int action,
67 const void *data, size_t len,
68 union kernfs_node_id *cgid)
69{
70 struct blk_io_trace *t;
71 struct ring_buffer_event *event = NULL;
72 struct ring_buffer *buffer = NULL;
73 int pc = 0;
74 int cpu = smp_processor_id();
75 bool blk_tracer = blk_tracer_enabled;
76 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
77
78 if (blk_tracer) {
79 buffer = blk_tr->trace_buffer.buffer;
80 pc = preempt_count();
81 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
82 sizeof(*t) + len + cgid_len,
83 0, pc);
84 if (!event)
85 return;
86 t = ring_buffer_event_data(event);
87 goto record_it;
88 }
89
90 if (!bt->rchan)
91 return;
92
93 t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len);
94 if (t) {
95 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
96 t->time = ktime_to_ns(ktime_get());
97record_it:
98 t->device = bt->dev;
99 t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
100 t->pid = pid;
101 t->cpu = cpu;
102 t->pdu_len = len + cgid_len;
103 if (cgid)
104 memcpy((void *)t + sizeof(*t), cgid, cgid_len);
105 memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
106
107 if (blk_tracer)
108 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
109 }
110}
111
112/*
113 * Send out a notify for this process, if we haven't done so since a trace
114 * started
115 */
116static void trace_note_tsk(struct task_struct *tsk)
117{
118 unsigned long flags;
119 struct blk_trace *bt;
120
121 tsk->btrace_seq = blktrace_seq;
122 spin_lock_irqsave(&running_trace_lock, flags);
123 list_for_each_entry(bt, &running_trace_list, running_list) {
124 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
125 sizeof(tsk->comm), NULL);
126 }
127 spin_unlock_irqrestore(&running_trace_lock, flags);
128}
129
130static void trace_note_time(struct blk_trace *bt)
131{
132 struct timespec64 now;
133 unsigned long flags;
134 u32 words[2];
135
136 /* need to check user space to see if this breaks in y2038 or y2106 */
137 ktime_get_real_ts64(&now);
138 words[0] = (u32)now.tv_sec;
139 words[1] = now.tv_nsec;
140
141 local_irq_save(flags);
142 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), NULL);
143 local_irq_restore(flags);
144}
145
146void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
147 const char *fmt, ...)
148{
149 int n;
150 va_list args;
151 unsigned long flags;
152 char *buf;
153
154 if (unlikely(bt->trace_state != Blktrace_running &&
155 !blk_tracer_enabled))
156 return;
157
158 /*
159 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
160 * message to the trace.
161 */
162 if (!(bt->act_mask & BLK_TC_NOTIFY))
163 return;
164
165 local_irq_save(flags);
166 buf = this_cpu_ptr(bt->msg_data);
167 va_start(args, fmt);
168 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
169 va_end(args);
170
171 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
172 blkcg = NULL;
173#ifdef CONFIG_BLK_CGROUP
174 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n,
175 blkcg ? cgroup_get_kernfs_id(blkcg->css.cgroup) : NULL);
176#else
177 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL);
178#endif
179 local_irq_restore(flags);
180}
181EXPORT_SYMBOL_GPL(__trace_note_message);
182
183static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
184 pid_t pid)
185{
186 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
187 return 1;
188 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
189 return 1;
190 if (bt->pid && pid != bt->pid)
191 return 1;
192
193 return 0;
194}
195
196/*
197 * Data direction bit lookup
198 */
199static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
200 BLK_TC_ACT(BLK_TC_WRITE) };
201
202#define BLK_TC_RAHEAD BLK_TC_AHEAD
203#define BLK_TC_PREFLUSH BLK_TC_FLUSH
204
205/* The ilog2() calls fall out because they're constant */
206#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
207 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
208
209/*
210 * The worker for the various blk_add_trace*() types. Fills out a
211 * blk_io_trace structure and places it in a per-cpu subbuffer.
212 */
213static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
214 int op, int op_flags, u32 what, int error, int pdu_len,
215 void *pdu_data, union kernfs_node_id *cgid)
216{
217 struct task_struct *tsk = current;
218 struct ring_buffer_event *event = NULL;
219 struct ring_buffer *buffer = NULL;
220 struct blk_io_trace *t;
221 unsigned long flags = 0;
222 unsigned long *sequence;
223 pid_t pid;
224 int cpu, pc = 0;
225 bool blk_tracer = blk_tracer_enabled;
226 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
227
228 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
229 return;
230
231 what |= ddir_act[op_is_write(op) ? WRITE : READ];
232 what |= MASK_TC_BIT(op_flags, SYNC);
233 what |= MASK_TC_BIT(op_flags, RAHEAD);
234 what |= MASK_TC_BIT(op_flags, META);
235 what |= MASK_TC_BIT(op_flags, PREFLUSH);
236 what |= MASK_TC_BIT(op_flags, FUA);
237 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
238 what |= BLK_TC_ACT(BLK_TC_DISCARD);
239 if (op == REQ_OP_FLUSH)
240 what |= BLK_TC_ACT(BLK_TC_FLUSH);
241 if (cgid)
242 what |= __BLK_TA_CGROUP;
243
244 pid = tsk->pid;
245 if (act_log_check(bt, what, sector, pid))
246 return;
247 cpu = raw_smp_processor_id();
248
249 if (blk_tracer) {
250 tracing_record_cmdline(current);
251
252 buffer = blk_tr->trace_buffer.buffer;
253 pc = preempt_count();
254 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
255 sizeof(*t) + pdu_len + cgid_len,
256 0, pc);
257 if (!event)
258 return;
259 t = ring_buffer_event_data(event);
260 goto record_it;
261 }
262
263 if (unlikely(tsk->btrace_seq != blktrace_seq))
264 trace_note_tsk(tsk);
265
266 /*
267 * A word about the locking here - we disable interrupts to reserve
268 * some space in the relay per-cpu buffer, to prevent an irq
269 * from coming in and stepping on our toes.
270 */
271 local_irq_save(flags);
272 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
273 if (t) {
274 sequence = per_cpu_ptr(bt->sequence, cpu);
275
276 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
277 t->sequence = ++(*sequence);
278 t->time = ktime_to_ns(ktime_get());
279record_it:
280 /*
281 * These two are not needed in ftrace as they are in the
282 * generic trace_entry, filled by tracing_generic_entry_update,
283 * but for the trace_event->bin() synthesizer benefit we do it
284 * here too.
285 */
286 t->cpu = cpu;
287 t->pid = pid;
288
289 t->sector = sector;
290 t->bytes = bytes;
291 t->action = what;
292 t->device = bt->dev;
293 t->error = error;
294 t->pdu_len = pdu_len + cgid_len;
295
296 if (cgid_len)
297 memcpy((void *)t + sizeof(*t), cgid, cgid_len);
298 if (pdu_len)
299 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
300
301 if (blk_tracer) {
302 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
303 return;
304 }
305 }
306
307 local_irq_restore(flags);
308}
309
310static void blk_trace_free(struct blk_trace *bt)
311{
312 debugfs_remove(bt->msg_file);
313 debugfs_remove(bt->dropped_file);
314 relay_close(bt->rchan);
315 debugfs_remove(bt->dir);
316 free_percpu(bt->sequence);
317 free_percpu(bt->msg_data);
318 kfree(bt);
319}
320
321static void get_probe_ref(void)
322{
323 mutex_lock(&blk_probe_mutex);
324 if (++blk_probes_ref == 1)
325 blk_register_tracepoints();
326 mutex_unlock(&blk_probe_mutex);
327}
328
329static void put_probe_ref(void)
330{
331 mutex_lock(&blk_probe_mutex);
332 if (!--blk_probes_ref)
333 blk_unregister_tracepoints();
334 mutex_unlock(&blk_probe_mutex);
335}
336
337static void blk_trace_cleanup(struct blk_trace *bt)
338{
339 blk_trace_free(bt);
340 put_probe_ref();
341}
342
343static int __blk_trace_remove(struct request_queue *q)
344{
345 struct blk_trace *bt;
346
347 bt = xchg(&q->blk_trace, NULL);
348 if (!bt)
349 return -EINVAL;
350
351 if (bt->trace_state != Blktrace_running)
352 blk_trace_cleanup(bt);
353
354 return 0;
355}
356
357int blk_trace_remove(struct request_queue *q)
358{
359 int ret;
360
361 mutex_lock(&q->blk_trace_mutex);
362 ret = __blk_trace_remove(q);
363 mutex_unlock(&q->blk_trace_mutex);
364
365 return ret;
366}
367EXPORT_SYMBOL_GPL(blk_trace_remove);
368
369static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
370 size_t count, loff_t *ppos)
371{
372 struct blk_trace *bt = filp->private_data;
373 char buf[16];
374
375 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
376
377 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
378}
379
380static const struct file_operations blk_dropped_fops = {
381 .owner = THIS_MODULE,
382 .open = simple_open,
383 .read = blk_dropped_read,
384 .llseek = default_llseek,
385};
386
387static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
388 size_t count, loff_t *ppos)
389{
390 char *msg;
391 struct blk_trace *bt;
392
393 if (count >= BLK_TN_MAX_MSG)
394 return -EINVAL;
395
396 msg = memdup_user_nul(buffer, count);
397 if (IS_ERR(msg))
398 return PTR_ERR(msg);
399
400 bt = filp->private_data;
401 __trace_note_message(bt, NULL, "%s", msg);
402 kfree(msg);
403
404 return count;
405}
406
407static const struct file_operations blk_msg_fops = {
408 .owner = THIS_MODULE,
409 .open = simple_open,
410 .write = blk_msg_write,
411 .llseek = noop_llseek,
412};
413
414/*
415 * Keep track of how many times we encountered a full subbuffer, to aid
416 * the user space app in telling how many lost events there were.
417 */
418static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
419 void *prev_subbuf, size_t prev_padding)
420{
421 struct blk_trace *bt;
422
423 if (!relay_buf_full(buf))
424 return 1;
425
426 bt = buf->chan->private_data;
427 atomic_inc(&bt->dropped);
428 return 0;
429}
430
431static int blk_remove_buf_file_callback(struct dentry *dentry)
432{
433 debugfs_remove(dentry);
434
435 return 0;
436}
437
438static struct dentry *blk_create_buf_file_callback(const char *filename,
439 struct dentry *parent,
440 umode_t mode,
441 struct rchan_buf *buf,
442 int *is_global)
443{
444 return debugfs_create_file(filename, mode, parent, buf,
445 &relay_file_operations);
446}
447
448static struct rchan_callbacks blk_relay_callbacks = {
449 .subbuf_start = blk_subbuf_start_callback,
450 .create_buf_file = blk_create_buf_file_callback,
451 .remove_buf_file = blk_remove_buf_file_callback,
452};
453
454static void blk_trace_setup_lba(struct blk_trace *bt,
455 struct block_device *bdev)
456{
457 struct hd_struct *part = NULL;
458
459 if (bdev)
460 part = bdev->bd_part;
461
462 if (part) {
463 bt->start_lba = part->start_sect;
464 bt->end_lba = part->start_sect + part->nr_sects;
465 } else {
466 bt->start_lba = 0;
467 bt->end_lba = -1ULL;
468 }
469}
470
471/*
472 * Setup everything required to start tracing
473 */
474static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
475 struct block_device *bdev,
476 struct blk_user_trace_setup *buts)
477{
478 struct blk_trace *bt = NULL;
479 struct dentry *dir = NULL;
480 int ret;
481
482 if (!buts->buf_size || !buts->buf_nr)
483 return -EINVAL;
484
485 if (!blk_debugfs_root)
486 return -ENOENT;
487
488 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
489 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
490
491 /*
492 * some device names have larger paths - convert the slashes
493 * to underscores for this to work as expected
494 */
495 strreplace(buts->name, '/', '_');
496
497 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
498 if (!bt)
499 return -ENOMEM;
500
501 ret = -ENOMEM;
502 bt->sequence = alloc_percpu(unsigned long);
503 if (!bt->sequence)
504 goto err;
505
506 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
507 if (!bt->msg_data)
508 goto err;
509
510 ret = -ENOENT;
511
512 dir = debugfs_lookup(buts->name, blk_debugfs_root);
513 if (!dir)
514 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
515
516 bt->dev = dev;
517 atomic_set(&bt->dropped, 0);
518 INIT_LIST_HEAD(&bt->running_list);
519
520 ret = -EIO;
521 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
522 &blk_dropped_fops);
523
524 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
525
526 bt->rchan = relay_open("trace", dir, buts->buf_size,
527 buts->buf_nr, &blk_relay_callbacks, bt);
528 if (!bt->rchan)
529 goto err;
530
531 bt->act_mask = buts->act_mask;
532 if (!bt->act_mask)
533 bt->act_mask = (u16) -1;
534
535 blk_trace_setup_lba(bt, bdev);
536
537 /* overwrite with user settings */
538 if (buts->start_lba)
539 bt->start_lba = buts->start_lba;
540 if (buts->end_lba)
541 bt->end_lba = buts->end_lba;
542
543 bt->pid = buts->pid;
544 bt->trace_state = Blktrace_setup;
545
546 ret = -EBUSY;
547 if (cmpxchg(&q->blk_trace, NULL, bt))
548 goto err;
549
550 get_probe_ref();
551
552 ret = 0;
553err:
554 if (dir && !bt->dir)
555 dput(dir);
556 if (ret)
557 blk_trace_free(bt);
558 return ret;
559}
560
561static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
562 struct block_device *bdev, char __user *arg)
563{
564 struct blk_user_trace_setup buts;
565 int ret;
566
567 ret = copy_from_user(&buts, arg, sizeof(buts));
568 if (ret)
569 return -EFAULT;
570
571 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
572 if (ret)
573 return ret;
574
575 if (copy_to_user(arg, &buts, sizeof(buts))) {
576 __blk_trace_remove(q);
577 return -EFAULT;
578 }
579 return 0;
580}
581
582int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
583 struct block_device *bdev,
584 char __user *arg)
585{
586 int ret;
587
588 mutex_lock(&q->blk_trace_mutex);
589 ret = __blk_trace_setup(q, name, dev, bdev, arg);
590 mutex_unlock(&q->blk_trace_mutex);
591
592 return ret;
593}
594EXPORT_SYMBOL_GPL(blk_trace_setup);
595
596#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
597static int compat_blk_trace_setup(struct request_queue *q, char *name,
598 dev_t dev, struct block_device *bdev,
599 char __user *arg)
600{
601 struct blk_user_trace_setup buts;
602 struct compat_blk_user_trace_setup cbuts;
603 int ret;
604
605 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
606 return -EFAULT;
607
608 buts = (struct blk_user_trace_setup) {
609 .act_mask = cbuts.act_mask,
610 .buf_size = cbuts.buf_size,
611 .buf_nr = cbuts.buf_nr,
612 .start_lba = cbuts.start_lba,
613 .end_lba = cbuts.end_lba,
614 .pid = cbuts.pid,
615 };
616
617 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
618 if (ret)
619 return ret;
620
621 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
622 __blk_trace_remove(q);
623 return -EFAULT;
624 }
625
626 return 0;
627}
628#endif
629
630static int __blk_trace_startstop(struct request_queue *q, int start)
631{
632 int ret;
633 struct blk_trace *bt = q->blk_trace;
634
635 if (bt == NULL)
636 return -EINVAL;
637
638 /*
639 * For starting a trace, we can transition from a setup or stopped
640 * trace. For stopping a trace, the state must be running
641 */
642 ret = -EINVAL;
643 if (start) {
644 if (bt->trace_state == Blktrace_setup ||
645 bt->trace_state == Blktrace_stopped) {
646 blktrace_seq++;
647 smp_mb();
648 bt->trace_state = Blktrace_running;
649 spin_lock_irq(&running_trace_lock);
650 list_add(&bt->running_list, &running_trace_list);
651 spin_unlock_irq(&running_trace_lock);
652
653 trace_note_time(bt);
654 ret = 0;
655 }
656 } else {
657 if (bt->trace_state == Blktrace_running) {
658 bt->trace_state = Blktrace_stopped;
659 spin_lock_irq(&running_trace_lock);
660 list_del_init(&bt->running_list);
661 spin_unlock_irq(&running_trace_lock);
662 relay_flush(bt->rchan);
663 ret = 0;
664 }
665 }
666
667 return ret;
668}
669
670int blk_trace_startstop(struct request_queue *q, int start)
671{
672 int ret;
673
674 mutex_lock(&q->blk_trace_mutex);
675 ret = __blk_trace_startstop(q, start);
676 mutex_unlock(&q->blk_trace_mutex);
677
678 return ret;
679}
680EXPORT_SYMBOL_GPL(blk_trace_startstop);
681
682/*
683 * When reading or writing the blktrace sysfs files, the references to the
684 * opened sysfs or device files should prevent the underlying block device
685 * from being removed. So no further delete protection is really needed.
686 */
687
688/**
689 * blk_trace_ioctl: - handle the ioctls associated with tracing
690 * @bdev: the block device
691 * @cmd: the ioctl cmd
692 * @arg: the argument data, if any
693 *
694 **/
695int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
696{
697 struct request_queue *q;
698 int ret, start = 0;
699 char b[BDEVNAME_SIZE];
700
701 q = bdev_get_queue(bdev);
702 if (!q)
703 return -ENXIO;
704
705 mutex_lock(&q->blk_trace_mutex);
706
707 switch (cmd) {
708 case BLKTRACESETUP:
709 bdevname(bdev, b);
710 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
711 break;
712#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
713 case BLKTRACESETUP32:
714 bdevname(bdev, b);
715 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
716 break;
717#endif
718 case BLKTRACESTART:
719 start = 1;
720 /* fall through */
721 case BLKTRACESTOP:
722 ret = __blk_trace_startstop(q, start);
723 break;
724 case BLKTRACETEARDOWN:
725 ret = __blk_trace_remove(q);
726 break;
727 default:
728 ret = -ENOTTY;
729 break;
730 }
731
732 mutex_unlock(&q->blk_trace_mutex);
733 return ret;
734}
735
736/**
737 * blk_trace_shutdown: - stop and cleanup trace structures
738 * @q: the request queue associated with the device
739 *
740 **/
741void blk_trace_shutdown(struct request_queue *q)
742{
743 mutex_lock(&q->blk_trace_mutex);
744
745 if (q->blk_trace) {
746 __blk_trace_startstop(q, 0);
747 __blk_trace_remove(q);
748 }
749
750 mutex_unlock(&q->blk_trace_mutex);
751}
752
753#ifdef CONFIG_BLK_CGROUP
754static union kernfs_node_id *
755blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
756{
757 struct blk_trace *bt = q->blk_trace;
758
759 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
760 return NULL;
761
762 if (!bio->bi_blkg)
763 return NULL;
764 return cgroup_get_kernfs_id(bio_blkcg(bio)->css.cgroup);
765}
766#else
767static union kernfs_node_id *
768blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
769{
770 return NULL;
771}
772#endif
773
774static union kernfs_node_id *
775blk_trace_request_get_cgid(struct request_queue *q, struct request *rq)
776{
777 if (!rq->bio)
778 return NULL;
779 /* Use the first bio */
780 return blk_trace_bio_get_cgid(q, rq->bio);
781}
782
783/*
784 * blktrace probes
785 */
786
787/**
788 * blk_add_trace_rq - Add a trace for a request oriented action
789 * @rq: the source request
790 * @error: return status to log
791 * @nr_bytes: number of completed bytes
792 * @what: the action
793 * @cgid: the cgroup info
794 *
795 * Description:
796 * Records an action against a request. Will log the bio offset + size.
797 *
798 **/
799static void blk_add_trace_rq(struct request *rq, int error,
800 unsigned int nr_bytes, u32 what,
801 union kernfs_node_id *cgid)
802{
803 struct blk_trace *bt = rq->q->blk_trace;
804
805 if (likely(!bt))
806 return;
807
808 if (blk_rq_is_passthrough(rq))
809 what |= BLK_TC_ACT(BLK_TC_PC);
810 else
811 what |= BLK_TC_ACT(BLK_TC_FS);
812
813 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
814 rq->cmd_flags, what, error, 0, NULL, cgid);
815}
816
817static void blk_add_trace_rq_insert(void *ignore,
818 struct request_queue *q, struct request *rq)
819{
820 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
821 blk_trace_request_get_cgid(q, rq));
822}
823
824static void blk_add_trace_rq_issue(void *ignore,
825 struct request_queue *q, struct request *rq)
826{
827 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
828 blk_trace_request_get_cgid(q, rq));
829}
830
831static void blk_add_trace_rq_requeue(void *ignore,
832 struct request_queue *q,
833 struct request *rq)
834{
835 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
836 blk_trace_request_get_cgid(q, rq));
837}
838
839static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
840 int error, unsigned int nr_bytes)
841{
842 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
843 blk_trace_request_get_cgid(rq->q, rq));
844}
845
846/**
847 * blk_add_trace_bio - Add a trace for a bio oriented action
848 * @q: queue the io is for
849 * @bio: the source bio
850 * @what: the action
851 * @error: error, if any
852 *
853 * Description:
854 * Records an action against a bio. Will log the bio offset + size.
855 *
856 **/
857static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
858 u32 what, int error)
859{
860 struct blk_trace *bt = q->blk_trace;
861
862 if (likely(!bt))
863 return;
864
865 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
866 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
867 blk_trace_bio_get_cgid(q, bio));
868}
869
870static void blk_add_trace_bio_bounce(void *ignore,
871 struct request_queue *q, struct bio *bio)
872{
873 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
874}
875
876static void blk_add_trace_bio_complete(void *ignore,
877 struct request_queue *q, struct bio *bio,
878 int error)
879{
880 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
881}
882
883static void blk_add_trace_bio_backmerge(void *ignore,
884 struct request_queue *q,
885 struct request *rq,
886 struct bio *bio)
887{
888 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
889}
890
891static void blk_add_trace_bio_frontmerge(void *ignore,
892 struct request_queue *q,
893 struct request *rq,
894 struct bio *bio)
895{
896 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
897}
898
899static void blk_add_trace_bio_queue(void *ignore,
900 struct request_queue *q, struct bio *bio)
901{
902 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
903}
904
905static void blk_add_trace_getrq(void *ignore,
906 struct request_queue *q,
907 struct bio *bio, int rw)
908{
909 if (bio)
910 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
911 else {
912 struct blk_trace *bt = q->blk_trace;
913
914 if (bt)
915 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
916 NULL, NULL);
917 }
918}
919
920
921static void blk_add_trace_sleeprq(void *ignore,
922 struct request_queue *q,
923 struct bio *bio, int rw)
924{
925 if (bio)
926 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
927 else {
928 struct blk_trace *bt = q->blk_trace;
929
930 if (bt)
931 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
932 0, 0, NULL, NULL);
933 }
934}
935
936static void blk_add_trace_plug(void *ignore, struct request_queue *q)
937{
938 struct blk_trace *bt = q->blk_trace;
939
940 if (bt)
941 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, NULL);
942}
943
944static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
945 unsigned int depth, bool explicit)
946{
947 struct blk_trace *bt = q->blk_trace;
948
949 if (bt) {
950 __be64 rpdu = cpu_to_be64(depth);
951 u32 what;
952
953 if (explicit)
954 what = BLK_TA_UNPLUG_IO;
955 else
956 what = BLK_TA_UNPLUG_TIMER;
957
958 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, NULL);
959 }
960}
961
962static void blk_add_trace_split(void *ignore,
963 struct request_queue *q, struct bio *bio,
964 unsigned int pdu)
965{
966 struct blk_trace *bt = q->blk_trace;
967
968 if (bt) {
969 __be64 rpdu = cpu_to_be64(pdu);
970
971 __blk_add_trace(bt, bio->bi_iter.bi_sector,
972 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
973 BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu),
974 &rpdu, blk_trace_bio_get_cgid(q, bio));
975 }
976}
977
978/**
979 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
980 * @ignore: trace callback data parameter (not used)
981 * @q: queue the io is for
982 * @bio: the source bio
983 * @dev: target device
984 * @from: source sector
985 *
986 * Description:
987 * Device mapper or raid target sometimes need to split a bio because
988 * it spans a stripe (or similar). Add a trace for that action.
989 *
990 **/
991static void blk_add_trace_bio_remap(void *ignore,
992 struct request_queue *q, struct bio *bio,
993 dev_t dev, sector_t from)
994{
995 struct blk_trace *bt = q->blk_trace;
996 struct blk_io_trace_remap r;
997
998 if (likely(!bt))
999 return;
1000
1001 r.device_from = cpu_to_be32(dev);
1002 r.device_to = cpu_to_be32(bio_dev(bio));
1003 r.sector_from = cpu_to_be64(from);
1004
1005 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1006 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status,
1007 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1008}
1009
1010/**
1011 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1012 * @ignore: trace callback data parameter (not used)
1013 * @q: queue the io is for
1014 * @rq: the source request
1015 * @dev: target device
1016 * @from: source sector
1017 *
1018 * Description:
1019 * Device mapper remaps request to other devices.
1020 * Add a trace for that action.
1021 *
1022 **/
1023static void blk_add_trace_rq_remap(void *ignore,
1024 struct request_queue *q,
1025 struct request *rq, dev_t dev,
1026 sector_t from)
1027{
1028 struct blk_trace *bt = q->blk_trace;
1029 struct blk_io_trace_remap r;
1030
1031 if (likely(!bt))
1032 return;
1033
1034 r.device_from = cpu_to_be32(dev);
1035 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1036 r.sector_from = cpu_to_be64(from);
1037
1038 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1039 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1040 sizeof(r), &r, blk_trace_request_get_cgid(q, rq));
1041}
1042
1043/**
1044 * blk_add_driver_data - Add binary message with driver-specific data
1045 * @q: queue the io is for
1046 * @rq: io request
1047 * @data: driver-specific data
1048 * @len: length of driver-specific data
1049 *
1050 * Description:
1051 * Some drivers might want to write driver-specific data per request.
1052 *
1053 **/
1054void blk_add_driver_data(struct request_queue *q,
1055 struct request *rq,
1056 void *data, size_t len)
1057{
1058 struct blk_trace *bt = q->blk_trace;
1059
1060 if (likely(!bt))
1061 return;
1062
1063 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1064 BLK_TA_DRV_DATA, 0, len, data,
1065 blk_trace_request_get_cgid(q, rq));
1066}
1067EXPORT_SYMBOL_GPL(blk_add_driver_data);
1068
1069static void blk_register_tracepoints(void)
1070{
1071 int ret;
1072
1073 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1074 WARN_ON(ret);
1075 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1076 WARN_ON(ret);
1077 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1078 WARN_ON(ret);
1079 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1080 WARN_ON(ret);
1081 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1082 WARN_ON(ret);
1083 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1084 WARN_ON(ret);
1085 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1086 WARN_ON(ret);
1087 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1088 WARN_ON(ret);
1089 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1090 WARN_ON(ret);
1091 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1092 WARN_ON(ret);
1093 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1094 WARN_ON(ret);
1095 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1096 WARN_ON(ret);
1097 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1098 WARN_ON(ret);
1099 ret = register_trace_block_split(blk_add_trace_split, NULL);
1100 WARN_ON(ret);
1101 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1102 WARN_ON(ret);
1103 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1104 WARN_ON(ret);
1105}
1106
1107static void blk_unregister_tracepoints(void)
1108{
1109 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1110 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1111 unregister_trace_block_split(blk_add_trace_split, NULL);
1112 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1113 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1114 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1115 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1116 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1117 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1118 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1119 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1120 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1121 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1122 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1123 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1124 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1125
1126 tracepoint_synchronize_unregister();
1127}
1128
1129/*
1130 * struct blk_io_tracer formatting routines
1131 */
1132
1133static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1134{
1135 int i = 0;
1136 int tc = t->action >> BLK_TC_SHIFT;
1137
1138 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1139 rwbs[i++] = 'N';
1140 goto out;
1141 }
1142
1143 if (tc & BLK_TC_FLUSH)
1144 rwbs[i++] = 'F';
1145
1146 if (tc & BLK_TC_DISCARD)
1147 rwbs[i++] = 'D';
1148 else if (tc & BLK_TC_WRITE)
1149 rwbs[i++] = 'W';
1150 else if (t->bytes)
1151 rwbs[i++] = 'R';
1152 else
1153 rwbs[i++] = 'N';
1154
1155 if (tc & BLK_TC_FUA)
1156 rwbs[i++] = 'F';
1157 if (tc & BLK_TC_AHEAD)
1158 rwbs[i++] = 'A';
1159 if (tc & BLK_TC_SYNC)
1160 rwbs[i++] = 'S';
1161 if (tc & BLK_TC_META)
1162 rwbs[i++] = 'M';
1163out:
1164 rwbs[i] = '\0';
1165}
1166
1167static inline
1168const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1169{
1170 return (const struct blk_io_trace *)ent;
1171}
1172
1173static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1174{
1175 return (void *)(te_blk_io_trace(ent) + 1) +
1176 (has_cg ? sizeof(union kernfs_node_id) : 0);
1177}
1178
1179static inline const void *cgid_start(const struct trace_entry *ent)
1180{
1181 return (void *)(te_blk_io_trace(ent) + 1);
1182}
1183
1184static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1185{
1186 return te_blk_io_trace(ent)->pdu_len -
1187 (has_cg ? sizeof(union kernfs_node_id) : 0);
1188}
1189
1190static inline u32 t_action(const struct trace_entry *ent)
1191{
1192 return te_blk_io_trace(ent)->action;
1193}
1194
1195static inline u32 t_bytes(const struct trace_entry *ent)
1196{
1197 return te_blk_io_trace(ent)->bytes;
1198}
1199
1200static inline u32 t_sec(const struct trace_entry *ent)
1201{
1202 return te_blk_io_trace(ent)->bytes >> 9;
1203}
1204
1205static inline unsigned long long t_sector(const struct trace_entry *ent)
1206{
1207 return te_blk_io_trace(ent)->sector;
1208}
1209
1210static inline __u16 t_error(const struct trace_entry *ent)
1211{
1212 return te_blk_io_trace(ent)->error;
1213}
1214
1215static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1216{
1217 const __u64 *val = pdu_start(ent, has_cg);
1218 return be64_to_cpu(*val);
1219}
1220
1221static void get_pdu_remap(const struct trace_entry *ent,
1222 struct blk_io_trace_remap *r, bool has_cg)
1223{
1224 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1225 __u64 sector_from = __r->sector_from;
1226
1227 r->device_from = be32_to_cpu(__r->device_from);
1228 r->device_to = be32_to_cpu(__r->device_to);
1229 r->sector_from = be64_to_cpu(sector_from);
1230}
1231
1232typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1233 bool has_cg);
1234
1235static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1236 bool has_cg)
1237{
1238 char rwbs[RWBS_LEN];
1239 unsigned long long ts = iter->ts;
1240 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1241 unsigned secs = (unsigned long)ts;
1242 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1243
1244 fill_rwbs(rwbs, t);
1245
1246 trace_seq_printf(&iter->seq,
1247 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1248 MAJOR(t->device), MINOR(t->device), iter->cpu,
1249 secs, nsec_rem, iter->ent->pid, act, rwbs);
1250}
1251
1252static void blk_log_action(struct trace_iterator *iter, const char *act,
1253 bool has_cg)
1254{
1255 char rwbs[RWBS_LEN];
1256 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1257
1258 fill_rwbs(rwbs, t);
1259 if (has_cg) {
1260 const union kernfs_node_id *id = cgid_start(iter->ent);
1261
1262 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1263 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1264
1265 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1266 sizeof(blkcg_name_buf));
1267 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1268 MAJOR(t->device), MINOR(t->device),
1269 blkcg_name_buf, act, rwbs);
1270 } else
1271 trace_seq_printf(&iter->seq,
1272 "%3d,%-3d %x,%-x %2s %3s ",
1273 MAJOR(t->device), MINOR(t->device),
1274 id->ino, id->generation, act, rwbs);
1275 } else
1276 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1277 MAJOR(t->device), MINOR(t->device), act, rwbs);
1278}
1279
1280static void blk_log_dump_pdu(struct trace_seq *s,
1281 const struct trace_entry *ent, bool has_cg)
1282{
1283 const unsigned char *pdu_buf;
1284 int pdu_len;
1285 int i, end;
1286
1287 pdu_buf = pdu_start(ent, has_cg);
1288 pdu_len = pdu_real_len(ent, has_cg);
1289
1290 if (!pdu_len)
1291 return;
1292
1293 /* find the last zero that needs to be printed */
1294 for (end = pdu_len - 1; end >= 0; end--)
1295 if (pdu_buf[end])
1296 break;
1297 end++;
1298
1299 trace_seq_putc(s, '(');
1300
1301 for (i = 0; i < pdu_len; i++) {
1302
1303 trace_seq_printf(s, "%s%02x",
1304 i == 0 ? "" : " ", pdu_buf[i]);
1305
1306 /*
1307 * stop when the rest is just zeroes and indicate so
1308 * with a ".." appended
1309 */
1310 if (i == end && end != pdu_len - 1) {
1311 trace_seq_puts(s, " ..) ");
1312 return;
1313 }
1314 }
1315
1316 trace_seq_puts(s, ") ");
1317}
1318
1319static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1320{
1321 char cmd[TASK_COMM_LEN];
1322
1323 trace_find_cmdline(ent->pid, cmd);
1324
1325 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1326 trace_seq_printf(s, "%u ", t_bytes(ent));
1327 blk_log_dump_pdu(s, ent, has_cg);
1328 trace_seq_printf(s, "[%s]\n", cmd);
1329 } else {
1330 if (t_sec(ent))
1331 trace_seq_printf(s, "%llu + %u [%s]\n",
1332 t_sector(ent), t_sec(ent), cmd);
1333 else
1334 trace_seq_printf(s, "[%s]\n", cmd);
1335 }
1336}
1337
1338static void blk_log_with_error(struct trace_seq *s,
1339 const struct trace_entry *ent, bool has_cg)
1340{
1341 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1342 blk_log_dump_pdu(s, ent, has_cg);
1343 trace_seq_printf(s, "[%d]\n", t_error(ent));
1344 } else {
1345 if (t_sec(ent))
1346 trace_seq_printf(s, "%llu + %u [%d]\n",
1347 t_sector(ent),
1348 t_sec(ent), t_error(ent));
1349 else
1350 trace_seq_printf(s, "%llu [%d]\n",
1351 t_sector(ent), t_error(ent));
1352 }
1353}
1354
1355static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1356{
1357 struct blk_io_trace_remap r = { .device_from = 0, };
1358
1359 get_pdu_remap(ent, &r, has_cg);
1360 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1361 t_sector(ent), t_sec(ent),
1362 MAJOR(r.device_from), MINOR(r.device_from),
1363 (unsigned long long)r.sector_from);
1364}
1365
1366static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1367{
1368 char cmd[TASK_COMM_LEN];
1369
1370 trace_find_cmdline(ent->pid, cmd);
1371
1372 trace_seq_printf(s, "[%s]\n", cmd);
1373}
1374
1375static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1376{
1377 char cmd[TASK_COMM_LEN];
1378
1379 trace_find_cmdline(ent->pid, cmd);
1380
1381 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1382}
1383
1384static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1385{
1386 char cmd[TASK_COMM_LEN];
1387
1388 trace_find_cmdline(ent->pid, cmd);
1389
1390 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1391 get_pdu_int(ent, has_cg), cmd);
1392}
1393
1394static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1395 bool has_cg)
1396{
1397
1398 trace_seq_putmem(s, pdu_start(ent, has_cg),
1399 pdu_real_len(ent, has_cg));
1400 trace_seq_putc(s, '\n');
1401}
1402
1403/*
1404 * struct tracer operations
1405 */
1406
1407static void blk_tracer_print_header(struct seq_file *m)
1408{
1409 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1410 return;
1411 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1412 "# | | | | | |\n");
1413}
1414
1415static void blk_tracer_start(struct trace_array *tr)
1416{
1417 blk_tracer_enabled = true;
1418}
1419
1420static int blk_tracer_init(struct trace_array *tr)
1421{
1422 blk_tr = tr;
1423 blk_tracer_start(tr);
1424 return 0;
1425}
1426
1427static void blk_tracer_stop(struct trace_array *tr)
1428{
1429 blk_tracer_enabled = false;
1430}
1431
1432static void blk_tracer_reset(struct trace_array *tr)
1433{
1434 blk_tracer_stop(tr);
1435}
1436
1437static const struct {
1438 const char *act[2];
1439 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1440 bool has_cg);
1441} what2act[] = {
1442 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1443 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1444 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1445 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1446 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1447 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1448 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1449 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1450 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1451 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1452 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1453 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1454 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1455 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1456 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1457};
1458
1459static enum print_line_t print_one_line(struct trace_iterator *iter,
1460 bool classic)
1461{
1462 struct trace_array *tr = iter->tr;
1463 struct trace_seq *s = &iter->seq;
1464 const struct blk_io_trace *t;
1465 u16 what;
1466 bool long_act;
1467 blk_log_action_t *log_action;
1468 bool has_cg;
1469
1470 t = te_blk_io_trace(iter->ent);
1471 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1472 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1473 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1474 has_cg = t->action & __BLK_TA_CGROUP;
1475
1476 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1477 log_action(iter, long_act ? "message" : "m", has_cg);
1478 blk_log_msg(s, iter->ent, has_cg);
1479 return trace_handle_return(s);
1480 }
1481
1482 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1483 trace_seq_printf(s, "Unknown action %x\n", what);
1484 else {
1485 log_action(iter, what2act[what].act[long_act], has_cg);
1486 what2act[what].print(s, iter->ent, has_cg);
1487 }
1488
1489 return trace_handle_return(s);
1490}
1491
1492static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1493 int flags, struct trace_event *event)
1494{
1495 return print_one_line(iter, false);
1496}
1497
1498static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1499{
1500 struct trace_seq *s = &iter->seq;
1501 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1502 const int offset = offsetof(struct blk_io_trace, sector);
1503 struct blk_io_trace old = {
1504 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1505 .time = iter->ts,
1506 };
1507
1508 trace_seq_putmem(s, &old, offset);
1509 trace_seq_putmem(s, &t->sector,
1510 sizeof(old) - offset + t->pdu_len);
1511}
1512
1513static enum print_line_t
1514blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1515 struct trace_event *event)
1516{
1517 blk_trace_synthesize_old_trace(iter);
1518
1519 return trace_handle_return(&iter->seq);
1520}
1521
1522static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1523{
1524 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1525 return TRACE_TYPE_UNHANDLED;
1526
1527 return print_one_line(iter, true);
1528}
1529
1530static int
1531blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1532{
1533 /* don't output context-info for blk_classic output */
1534 if (bit == TRACE_BLK_OPT_CLASSIC) {
1535 if (set)
1536 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1537 else
1538 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1539 }
1540 return 0;
1541}
1542
1543static struct tracer blk_tracer __read_mostly = {
1544 .name = "blk",
1545 .init = blk_tracer_init,
1546 .reset = blk_tracer_reset,
1547 .start = blk_tracer_start,
1548 .stop = blk_tracer_stop,
1549 .print_header = blk_tracer_print_header,
1550 .print_line = blk_tracer_print_line,
1551 .flags = &blk_tracer_flags,
1552 .set_flag = blk_tracer_set_flag,
1553};
1554
1555static struct trace_event_functions trace_blk_event_funcs = {
1556 .trace = blk_trace_event_print,
1557 .binary = blk_trace_event_print_binary,
1558};
1559
1560static struct trace_event trace_blk_event = {
1561 .type = TRACE_BLK,
1562 .funcs = &trace_blk_event_funcs,
1563};
1564
1565static int __init init_blk_tracer(void)
1566{
1567 if (!register_trace_event(&trace_blk_event)) {
1568 pr_warn("Warning: could not register block events\n");
1569 return 1;
1570 }
1571
1572 if (register_tracer(&blk_tracer) != 0) {
1573 pr_warn("Warning: could not register the block tracer\n");
1574 unregister_trace_event(&trace_blk_event);
1575 return 1;
1576 }
1577
1578 return 0;
1579}
1580
1581device_initcall(init_blk_tracer);
1582
1583static int blk_trace_remove_queue(struct request_queue *q)
1584{
1585 struct blk_trace *bt;
1586
1587 bt = xchg(&q->blk_trace, NULL);
1588 if (bt == NULL)
1589 return -EINVAL;
1590
1591 put_probe_ref();
1592 blk_trace_free(bt);
1593 return 0;
1594}
1595
1596/*
1597 * Setup everything required to start tracing
1598 */
1599static int blk_trace_setup_queue(struct request_queue *q,
1600 struct block_device *bdev)
1601{
1602 struct blk_trace *bt = NULL;
1603 int ret = -ENOMEM;
1604
1605 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1606 if (!bt)
1607 return -ENOMEM;
1608
1609 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1610 if (!bt->msg_data)
1611 goto free_bt;
1612
1613 bt->dev = bdev->bd_dev;
1614 bt->act_mask = (u16)-1;
1615
1616 blk_trace_setup_lba(bt, bdev);
1617
1618 ret = -EBUSY;
1619 if (cmpxchg(&q->blk_trace, NULL, bt))
1620 goto free_bt;
1621
1622 get_probe_ref();
1623 return 0;
1624
1625free_bt:
1626 blk_trace_free(bt);
1627 return ret;
1628}
1629
1630/*
1631 * sysfs interface to enable and configure tracing
1632 */
1633
1634static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1635 struct device_attribute *attr,
1636 char *buf);
1637static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1638 struct device_attribute *attr,
1639 const char *buf, size_t count);
1640#define BLK_TRACE_DEVICE_ATTR(_name) \
1641 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1642 sysfs_blk_trace_attr_show, \
1643 sysfs_blk_trace_attr_store)
1644
1645static BLK_TRACE_DEVICE_ATTR(enable);
1646static BLK_TRACE_DEVICE_ATTR(act_mask);
1647static BLK_TRACE_DEVICE_ATTR(pid);
1648static BLK_TRACE_DEVICE_ATTR(start_lba);
1649static BLK_TRACE_DEVICE_ATTR(end_lba);
1650
1651static struct attribute *blk_trace_attrs[] = {
1652 &dev_attr_enable.attr,
1653 &dev_attr_act_mask.attr,
1654 &dev_attr_pid.attr,
1655 &dev_attr_start_lba.attr,
1656 &dev_attr_end_lba.attr,
1657 NULL
1658};
1659
1660struct attribute_group blk_trace_attr_group = {
1661 .name = "trace",
1662 .attrs = blk_trace_attrs,
1663};
1664
1665static const struct {
1666 int mask;
1667 const char *str;
1668} mask_maps[] = {
1669 { BLK_TC_READ, "read" },
1670 { BLK_TC_WRITE, "write" },
1671 { BLK_TC_FLUSH, "flush" },
1672 { BLK_TC_SYNC, "sync" },
1673 { BLK_TC_QUEUE, "queue" },
1674 { BLK_TC_REQUEUE, "requeue" },
1675 { BLK_TC_ISSUE, "issue" },
1676 { BLK_TC_COMPLETE, "complete" },
1677 { BLK_TC_FS, "fs" },
1678 { BLK_TC_PC, "pc" },
1679 { BLK_TC_NOTIFY, "notify" },
1680 { BLK_TC_AHEAD, "ahead" },
1681 { BLK_TC_META, "meta" },
1682 { BLK_TC_DISCARD, "discard" },
1683 { BLK_TC_DRV_DATA, "drv_data" },
1684 { BLK_TC_FUA, "fua" },
1685};
1686
1687static int blk_trace_str2mask(const char *str)
1688{
1689 int i;
1690 int mask = 0;
1691 char *buf, *s, *token;
1692
1693 buf = kstrdup(str, GFP_KERNEL);
1694 if (buf == NULL)
1695 return -ENOMEM;
1696 s = strstrip(buf);
1697
1698 while (1) {
1699 token = strsep(&s, ",");
1700 if (token == NULL)
1701 break;
1702
1703 if (*token == '\0')
1704 continue;
1705
1706 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1707 if (strcasecmp(token, mask_maps[i].str) == 0) {
1708 mask |= mask_maps[i].mask;
1709 break;
1710 }
1711 }
1712 if (i == ARRAY_SIZE(mask_maps)) {
1713 mask = -EINVAL;
1714 break;
1715 }
1716 }
1717 kfree(buf);
1718
1719 return mask;
1720}
1721
1722static ssize_t blk_trace_mask2str(char *buf, int mask)
1723{
1724 int i;
1725 char *p = buf;
1726
1727 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1728 if (mask & mask_maps[i].mask) {
1729 p += sprintf(p, "%s%s",
1730 (p == buf) ? "" : ",", mask_maps[i].str);
1731 }
1732 }
1733 *p++ = '\n';
1734
1735 return p - buf;
1736}
1737
1738static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1739{
1740 if (bdev->bd_disk == NULL)
1741 return NULL;
1742
1743 return bdev_get_queue(bdev);
1744}
1745
1746static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1747 struct device_attribute *attr,
1748 char *buf)
1749{
1750 struct hd_struct *p = dev_to_part(dev);
1751 struct request_queue *q;
1752 struct block_device *bdev;
1753 ssize_t ret = -ENXIO;
1754
1755 bdev = bdget(part_devt(p));
1756 if (bdev == NULL)
1757 goto out;
1758
1759 q = blk_trace_get_queue(bdev);
1760 if (q == NULL)
1761 goto out_bdput;
1762
1763 mutex_lock(&q->blk_trace_mutex);
1764
1765 if (attr == &dev_attr_enable) {
1766 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1767 goto out_unlock_bdev;
1768 }
1769
1770 if (q->blk_trace == NULL)
1771 ret = sprintf(buf, "disabled\n");
1772 else if (attr == &dev_attr_act_mask)
1773 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1774 else if (attr == &dev_attr_pid)
1775 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1776 else if (attr == &dev_attr_start_lba)
1777 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1778 else if (attr == &dev_attr_end_lba)
1779 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1780
1781out_unlock_bdev:
1782 mutex_unlock(&q->blk_trace_mutex);
1783out_bdput:
1784 bdput(bdev);
1785out:
1786 return ret;
1787}
1788
1789static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1790 struct device_attribute *attr,
1791 const char *buf, size_t count)
1792{
1793 struct block_device *bdev;
1794 struct request_queue *q;
1795 struct hd_struct *p;
1796 u64 value;
1797 ssize_t ret = -EINVAL;
1798
1799 if (count == 0)
1800 goto out;
1801
1802 if (attr == &dev_attr_act_mask) {
1803 if (kstrtoull(buf, 0, &value)) {
1804 /* Assume it is a list of trace category names */
1805 ret = blk_trace_str2mask(buf);
1806 if (ret < 0)
1807 goto out;
1808 value = ret;
1809 }
1810 } else if (kstrtoull(buf, 0, &value))
1811 goto out;
1812
1813 ret = -ENXIO;
1814
1815 p = dev_to_part(dev);
1816 bdev = bdget(part_devt(p));
1817 if (bdev == NULL)
1818 goto out;
1819
1820 q = blk_trace_get_queue(bdev);
1821 if (q == NULL)
1822 goto out_bdput;
1823
1824 mutex_lock(&q->blk_trace_mutex);
1825
1826 if (attr == &dev_attr_enable) {
1827 if (!!value == !!q->blk_trace) {
1828 ret = 0;
1829 goto out_unlock_bdev;
1830 }
1831 if (value)
1832 ret = blk_trace_setup_queue(q, bdev);
1833 else
1834 ret = blk_trace_remove_queue(q);
1835 goto out_unlock_bdev;
1836 }
1837
1838 ret = 0;
1839 if (q->blk_trace == NULL)
1840 ret = blk_trace_setup_queue(q, bdev);
1841
1842 if (ret == 0) {
1843 if (attr == &dev_attr_act_mask)
1844 q->blk_trace->act_mask = value;
1845 else if (attr == &dev_attr_pid)
1846 q->blk_trace->pid = value;
1847 else if (attr == &dev_attr_start_lba)
1848 q->blk_trace->start_lba = value;
1849 else if (attr == &dev_attr_end_lba)
1850 q->blk_trace->end_lba = value;
1851 }
1852
1853out_unlock_bdev:
1854 mutex_unlock(&q->blk_trace_mutex);
1855out_bdput:
1856 bdput(bdev);
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
1875void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
1876{
1877 int i = 0;
1878
1879 if (op & REQ_PREFLUSH)
1880 rwbs[i++] = 'F';
1881
1882 switch (op & REQ_OP_MASK) {
1883 case REQ_OP_WRITE:
1884 case REQ_OP_WRITE_SAME:
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 (op & REQ_FUA)
1905 rwbs[i++] = 'F';
1906 if (op & REQ_RAHEAD)
1907 rwbs[i++] = 'A';
1908 if (op & REQ_SYNC)
1909 rwbs[i++] = 'S';
1910 if (op & 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