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