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pinctrl: st: Enhance the controller to manage unavailable registers
[linux/fpc-iii.git] / kernel / trace / blktrace.c
blobb418cb0d72424ab454e66e3cde881784ce1f0fad
1 /*
2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
16 *
17 */
18 #include <linux/kernel.h>
19 #include <linux/blkdev.h>
20 #include <linux/blktrace_api.h>
21 #include <linux/percpu.h>
22 #include <linux/init.h>
23 #include <linux/mutex.h>
24 #include <linux/slab.h>
25 #include <linux/debugfs.h>
26 #include <linux/export.h>
27 #include <linux/time.h>
28 #include <linux/uaccess.h>
29 #include <linux/list.h>
30
31 #include <trace/events/block.h>
32
33 #include "trace_output.h"
34
35 #ifdef CONFIG_BLK_DEV_IO_TRACE
36
37 static unsigned int blktrace_seq __read_mostly = 1;
38
39 static struct trace_array *blk_tr;
40 static bool blk_tracer_enabled __read_mostly;
41
42 static LIST_HEAD(running_trace_list);
43 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
44
45 /* Select an alternative, minimalistic output than the original one */
46 #define TRACE_BLK_OPT_CLASSIC 0x1
47
48 static struct tracer_opt blk_tracer_opts[] = {
49 /* Default disable the minimalistic output */
50 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
51 { }
52 };
53
54 static struct tracer_flags blk_tracer_flags = {
55 .val = 0,
56 .opts = blk_tracer_opts,
57 };
58
59 /* Global reference count of probes */
60 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
61
62 static void blk_register_tracepoints(void);
63 static void blk_unregister_tracepoints(void);
64
65 /*
66 * Send out a notify message.
67 */
68 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
69 const void *data, size_t len)
70 {
71 struct blk_io_trace *t;
72 struct ring_buffer_event *event = NULL;
73 struct ring_buffer *buffer = NULL;
74 int pc = 0;
75 int cpu = smp_processor_id();
76 bool blk_tracer = blk_tracer_enabled;
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,
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);
94 if (t) {
95 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
96 t->time = ktime_to_ns(ktime_get());
97 record_it:
98 t->device = bt->dev;
99 t->action = action;
100 t->pid = pid;
101 t->cpu = cpu;
102 t->pdu_len = len;
103 memcpy((void *) t + sizeof(*t), data, len);
104
105 if (blk_tracer)
106 trace_buffer_unlock_commit(buffer, event, 0, pc);
107 }
108 }
109
110 /*
111 * Send out a notify for this process, if we haven't done so since a trace
112 * started
113 */
114 static void trace_note_tsk(struct task_struct *tsk)
115 {
116 unsigned long flags;
117 struct blk_trace *bt;
118
119 tsk->btrace_seq = blktrace_seq;
120 spin_lock_irqsave(&running_trace_lock, flags);
121 list_for_each_entry(bt, &running_trace_list, running_list) {
122 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
123 sizeof(tsk->comm));
124 }
125 spin_unlock_irqrestore(&running_trace_lock, flags);
126 }
127
128 static void trace_note_time(struct blk_trace *bt)
129 {
130 struct timespec now;
131 unsigned long flags;
132 u32 words[2];
133
134 getnstimeofday(&now);
135 words[0] = now.tv_sec;
136 words[1] = now.tv_nsec;
137
138 local_irq_save(flags);
139 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
140 local_irq_restore(flags);
141 }
142
143 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
144 {
145 int n;
146 va_list args;
147 unsigned long flags;
148 char *buf;
149
150 if (unlikely(bt->trace_state != Blktrace_running &&
151 !blk_tracer_enabled))
152 return;
153
154 /*
155 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
156 * message to the trace.
157 */
158 if (!(bt->act_mask & BLK_TC_NOTIFY))
159 return;
160
161 local_irq_save(flags);
162 buf = this_cpu_ptr(bt->msg_data);
163 va_start(args, fmt);
164 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
165 va_end(args);
166
167 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
168 local_irq_restore(flags);
169 }
170 EXPORT_SYMBOL_GPL(__trace_note_message);
171
172 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
173 pid_t pid)
174 {
175 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
176 return 1;
177 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
178 return 1;
179 if (bt->pid && pid != bt->pid)
180 return 1;
181
182 return 0;
183 }
184
185 /*
186 * Data direction bit lookup
187 */
188 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
189 BLK_TC_ACT(BLK_TC_WRITE) };
190
191 #define BLK_TC_RAHEAD BLK_TC_AHEAD
192
193 /* The ilog2() calls fall out because they're constant */
194 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
195 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
196
197 /*
198 * The worker for the various blk_add_trace*() types. Fills out a
199 * blk_io_trace structure and places it in a per-cpu subbuffer.
200 */
201 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
202 int rw, u32 what, int error, int pdu_len, void *pdu_data)
203 {
204 struct task_struct *tsk = current;
205 struct ring_buffer_event *event = NULL;
206 struct ring_buffer *buffer = NULL;
207 struct blk_io_trace *t;
208 unsigned long flags = 0;
209 unsigned long *sequence;
210 pid_t pid;
211 int cpu, pc = 0;
212 bool blk_tracer = blk_tracer_enabled;
213
214 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
215 return;
216
217 what |= ddir_act[rw & WRITE];
218 what |= MASK_TC_BIT(rw, SYNC);
219 what |= MASK_TC_BIT(rw, RAHEAD);
220 what |= MASK_TC_BIT(rw, META);
221 what |= MASK_TC_BIT(rw, DISCARD);
222 what |= MASK_TC_BIT(rw, FLUSH);
223 what |= MASK_TC_BIT(rw, FUA);
224
225 pid = tsk->pid;
226 if (act_log_check(bt, what, sector, pid))
227 return;
228 cpu = raw_smp_processor_id();
229
230 if (blk_tracer) {
231 tracing_record_cmdline(current);
232
233 buffer = blk_tr->trace_buffer.buffer;
234 pc = preempt_count();
235 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
236 sizeof(*t) + pdu_len,
237 0, pc);
238 if (!event)
239 return;
240 t = ring_buffer_event_data(event);
241 goto record_it;
242 }
243
244 if (unlikely(tsk->btrace_seq != blktrace_seq))
245 trace_note_tsk(tsk);
246
247 /*
248 * A word about the locking here - we disable interrupts to reserve
249 * some space in the relay per-cpu buffer, to prevent an irq
250 * from coming in and stepping on our toes.
251 */
252 local_irq_save(flags);
253 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
254 if (t) {
255 sequence = per_cpu_ptr(bt->sequence, cpu);
256
257 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
258 t->sequence = ++(*sequence);
259 t->time = ktime_to_ns(ktime_get());
260 record_it:
261 /*
262 * These two are not needed in ftrace as they are in the
263 * generic trace_entry, filled by tracing_generic_entry_update,
264 * but for the trace_event->bin() synthesizer benefit we do it
265 * here too.
266 */
267 t->cpu = cpu;
268 t->pid = pid;
269
270 t->sector = sector;
271 t->bytes = bytes;
272 t->action = what;
273 t->device = bt->dev;
274 t->error = error;
275 t->pdu_len = pdu_len;
276
277 if (pdu_len)
278 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
279
280 if (blk_tracer) {
281 trace_buffer_unlock_commit(buffer, event, 0, pc);
282 return;
283 }
284 }
285
286 local_irq_restore(flags);
287 }
288
289 static struct dentry *blk_tree_root;
290 static DEFINE_MUTEX(blk_tree_mutex);
291
292 static void blk_trace_free(struct blk_trace *bt)
293 {
294 debugfs_remove(bt->msg_file);
295 debugfs_remove(bt->dropped_file);
296 relay_close(bt->rchan);
297 debugfs_remove(bt->dir);
298 free_percpu(bt->sequence);
299 free_percpu(bt->msg_data);
300 kfree(bt);
301 }
302
303 static void blk_trace_cleanup(struct blk_trace *bt)
304 {
305 blk_trace_free(bt);
306 if (atomic_dec_and_test(&blk_probes_ref))
307 blk_unregister_tracepoints();
308 }
309
310 int blk_trace_remove(struct request_queue *q)
311 {
312 struct blk_trace *bt;
313
314 bt = xchg(&q->blk_trace, NULL);
315 if (!bt)
316 return -EINVAL;
317
318 if (bt->trace_state != Blktrace_running)
319 blk_trace_cleanup(bt);
320
321 return 0;
322 }
323 EXPORT_SYMBOL_GPL(blk_trace_remove);
324
325 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
326 size_t count, loff_t *ppos)
327 {
328 struct blk_trace *bt = filp->private_data;
329 char buf[16];
330
331 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
332
333 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
334 }
335
336 static const struct file_operations blk_dropped_fops = {
337 .owner = THIS_MODULE,
338 .open = simple_open,
339 .read = blk_dropped_read,
340 .llseek = default_llseek,
341 };
342
343 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
344 size_t count, loff_t *ppos)
345 {
346 char *msg;
347 struct blk_trace *bt;
348
349 if (count >= BLK_TN_MAX_MSG)
350 return -EINVAL;
351
352 msg = kmalloc(count + 1, GFP_KERNEL);
353 if (msg == NULL)
354 return -ENOMEM;
355
356 if (copy_from_user(msg, buffer, count)) {
357 kfree(msg);
358 return -EFAULT;
359 }
360
361 msg[count] = '\0';
362 bt = filp->private_data;
363 __trace_note_message(bt, "%s", msg);
364 kfree(msg);
365
366 return count;
367 }
368
369 static const struct file_operations blk_msg_fops = {
370 .owner = THIS_MODULE,
371 .open = simple_open,
372 .write = blk_msg_write,
373 .llseek = noop_llseek,
374 };
375
376 /*
377 * Keep track of how many times we encountered a full subbuffer, to aid
378 * the user space app in telling how many lost events there were.
379 */
380 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
381 void *prev_subbuf, size_t prev_padding)
382 {
383 struct blk_trace *bt;
384
385 if (!relay_buf_full(buf))
386 return 1;
387
388 bt = buf->chan->private_data;
389 atomic_inc(&bt->dropped);
390 return 0;
391 }
392
393 static int blk_remove_buf_file_callback(struct dentry *dentry)
394 {
395 debugfs_remove(dentry);
396
397 return 0;
398 }
399
400 static struct dentry *blk_create_buf_file_callback(const char *filename,
401 struct dentry *parent,
402 umode_t mode,
403 struct rchan_buf *buf,
404 int *is_global)
405 {
406 return debugfs_create_file(filename, mode, parent, buf,
407 &relay_file_operations);
408 }
409
410 static struct rchan_callbacks blk_relay_callbacks = {
411 .subbuf_start = blk_subbuf_start_callback,
412 .create_buf_file = blk_create_buf_file_callback,
413 .remove_buf_file = blk_remove_buf_file_callback,
414 };
415
416 static void blk_trace_setup_lba(struct blk_trace *bt,
417 struct block_device *bdev)
418 {
419 struct hd_struct *part = NULL;
420
421 if (bdev)
422 part = bdev->bd_part;
423
424 if (part) {
425 bt->start_lba = part->start_sect;
426 bt->end_lba = part->start_sect + part->nr_sects;
427 } else {
428 bt->start_lba = 0;
429 bt->end_lba = -1ULL;
430 }
431 }
432
433 /*
434 * Setup everything required to start tracing
435 */
436 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
437 struct block_device *bdev,
438 struct blk_user_trace_setup *buts)
439 {
440 struct blk_trace *old_bt, *bt = NULL;
441 struct dentry *dir = NULL;
442 int ret, i;
443
444 if (!buts->buf_size || !buts->buf_nr)
445 return -EINVAL;
446
447 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
448 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
449
450 /*
451 * some device names have larger paths - convert the slashes
452 * to underscores for this to work as expected
453 */
454 for (i = 0; i < strlen(buts->name); i++)
455 if (buts->name[i] == '/')
456 buts->name[i] = '_';
457
458 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
459 if (!bt)
460 return -ENOMEM;
461
462 ret = -ENOMEM;
463 bt->sequence = alloc_percpu(unsigned long);
464 if (!bt->sequence)
465 goto err;
466
467 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
468 if (!bt->msg_data)
469 goto err;
470
471 ret = -ENOENT;
472
473 mutex_lock(&blk_tree_mutex);
474 if (!blk_tree_root) {
475 blk_tree_root = debugfs_create_dir("block", NULL);
476 if (!blk_tree_root) {
477 mutex_unlock(&blk_tree_mutex);
478 goto err;
479 }
480 }
481 mutex_unlock(&blk_tree_mutex);
482
483 dir = debugfs_create_dir(buts->name, blk_tree_root);
484
485 if (!dir)
486 goto err;
487
488 bt->dir = dir;
489 bt->dev = dev;
490 atomic_set(&bt->dropped, 0);
491 INIT_LIST_HEAD(&bt->running_list);
492
493 ret = -EIO;
494 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
495 &blk_dropped_fops);
496 if (!bt->dropped_file)
497 goto err;
498
499 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
500 if (!bt->msg_file)
501 goto err;
502
503 bt->rchan = relay_open("trace", dir, buts->buf_size,
504 buts->buf_nr, &blk_relay_callbacks, bt);
505 if (!bt->rchan)
506 goto err;
507
508 bt->act_mask = buts->act_mask;
509 if (!bt->act_mask)
510 bt->act_mask = (u16) -1;
511
512 blk_trace_setup_lba(bt, bdev);
513
514 /* overwrite with user settings */
515 if (buts->start_lba)
516 bt->start_lba = buts->start_lba;
517 if (buts->end_lba)
518 bt->end_lba = buts->end_lba;
519
520 bt->pid = buts->pid;
521 bt->trace_state = Blktrace_setup;
522
523 ret = -EBUSY;
524 old_bt = xchg(&q->blk_trace, bt);
525 if (old_bt) {
526 (void) xchg(&q->blk_trace, old_bt);
527 goto err;
528 }
529
530 if (atomic_inc_return(&blk_probes_ref) == 1)
531 blk_register_tracepoints();
532
533 return 0;
534 err:
535 blk_trace_free(bt);
536 return ret;
537 }
538
539 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
540 struct block_device *bdev,
541 char __user *arg)
542 {
543 struct blk_user_trace_setup buts;
544 int ret;
545
546 ret = copy_from_user(&buts, arg, sizeof(buts));
547 if (ret)
548 return -EFAULT;
549
550 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
551 if (ret)
552 return ret;
553
554 if (copy_to_user(arg, &buts, sizeof(buts))) {
555 blk_trace_remove(q);
556 return -EFAULT;
557 }
558 return 0;
559 }
560 EXPORT_SYMBOL_GPL(blk_trace_setup);
561
562 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
563 static int compat_blk_trace_setup(struct request_queue *q, char *name,
564 dev_t dev, struct block_device *bdev,
565 char __user *arg)
566 {
567 struct blk_user_trace_setup buts;
568 struct compat_blk_user_trace_setup cbuts;
569 int ret;
570
571 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
572 return -EFAULT;
573
574 buts = (struct blk_user_trace_setup) {
575 .act_mask = cbuts.act_mask,
576 .buf_size = cbuts.buf_size,
577 .buf_nr = cbuts.buf_nr,
578 .start_lba = cbuts.start_lba,
579 .end_lba = cbuts.end_lba,
580 .pid = cbuts.pid,
581 };
582
583 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
584 if (ret)
585 return ret;
586
587 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
588 blk_trace_remove(q);
589 return -EFAULT;
590 }
591
592 return 0;
593 }
594 #endif
595
596 int blk_trace_startstop(struct request_queue *q, int start)
597 {
598 int ret;
599 struct blk_trace *bt = q->blk_trace;
600
601 if (bt == NULL)
602 return -EINVAL;
603
604 /*
605 * For starting a trace, we can transition from a setup or stopped
606 * trace. For stopping a trace, the state must be running
607 */
608 ret = -EINVAL;
609 if (start) {
610 if (bt->trace_state == Blktrace_setup ||
611 bt->trace_state == Blktrace_stopped) {
612 blktrace_seq++;
613 smp_mb();
614 bt->trace_state = Blktrace_running;
615 spin_lock_irq(&running_trace_lock);
616 list_add(&bt->running_list, &running_trace_list);
617 spin_unlock_irq(&running_trace_lock);
618
619 trace_note_time(bt);
620 ret = 0;
621 }
622 } else {
623 if (bt->trace_state == Blktrace_running) {
624 bt->trace_state = Blktrace_stopped;
625 spin_lock_irq(&running_trace_lock);
626 list_del_init(&bt->running_list);
627 spin_unlock_irq(&running_trace_lock);
628 relay_flush(bt->rchan);
629 ret = 0;
630 }
631 }
632
633 return ret;
634 }
635 EXPORT_SYMBOL_GPL(blk_trace_startstop);
636
637 /**
638 * blk_trace_ioctl: - handle the ioctls associated with tracing
639 * @bdev: the block device
640 * @cmd: the ioctl cmd
641 * @arg: the argument data, if any
642 *
643 **/
644 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
645 {
646 struct request_queue *q;
647 int ret, start = 0;
648 char b[BDEVNAME_SIZE];
649
650 q = bdev_get_queue(bdev);
651 if (!q)
652 return -ENXIO;
653
654 mutex_lock(&bdev->bd_mutex);
655
656 switch (cmd) {
657 case BLKTRACESETUP:
658 bdevname(bdev, b);
659 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
660 break;
661 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
662 case BLKTRACESETUP32:
663 bdevname(bdev, b);
664 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
665 break;
666 #endif
667 case BLKTRACESTART:
668 start = 1;
669 case BLKTRACESTOP:
670 ret = blk_trace_startstop(q, start);
671 break;
672 case BLKTRACETEARDOWN:
673 ret = blk_trace_remove(q);
674 break;
675 default:
676 ret = -ENOTTY;
677 break;
678 }
679
680 mutex_unlock(&bdev->bd_mutex);
681 return ret;
682 }
683
684 /**
685 * blk_trace_shutdown: - stop and cleanup trace structures
686 * @q: the request queue associated with the device
687 *
688 **/
689 void blk_trace_shutdown(struct request_queue *q)
690 {
691 if (q->blk_trace) {
692 blk_trace_startstop(q, 0);
693 blk_trace_remove(q);
694 }
695 }
696
697 /*
698 * blktrace probes
699 */
700
701 /**
702 * blk_add_trace_rq - Add a trace for a request oriented action
703 * @q: queue the io is for
704 * @rq: the source request
705 * @what: the action
706 *
707 * Description:
708 * Records an action against a request. Will log the bio offset + size.
709 *
710 **/
711 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
712 u32 what)
713 {
714 struct blk_trace *bt = q->blk_trace;
715
716 if (likely(!bt))
717 return;
718
719 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
720 what |= BLK_TC_ACT(BLK_TC_PC);
721 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
722 what, rq->errors, rq->cmd_len, rq->cmd);
723 } else {
724 what |= BLK_TC_ACT(BLK_TC_FS);
725 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
726 rq->cmd_flags, what, rq->errors, 0, NULL);
727 }
728 }
729
730 static void blk_add_trace_rq_abort(void *ignore,
731 struct request_queue *q, struct request *rq)
732 {
733 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
734 }
735
736 static void blk_add_trace_rq_insert(void *ignore,
737 struct request_queue *q, struct request *rq)
738 {
739 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
740 }
741
742 static void blk_add_trace_rq_issue(void *ignore,
743 struct request_queue *q, struct request *rq)
744 {
745 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
746 }
747
748 static void blk_add_trace_rq_requeue(void *ignore,
749 struct request_queue *q,
750 struct request *rq)
751 {
752 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
753 }
754
755 static void blk_add_trace_rq_complete(void *ignore,
756 struct request_queue *q,
757 struct request *rq)
758 {
759 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
760 }
761
762 /**
763 * blk_add_trace_bio - Add a trace for a bio oriented action
764 * @q: queue the io is for
765 * @bio: the source bio
766 * @what: the action
767 * @error: error, if any
768 *
769 * Description:
770 * Records an action against a bio. Will log the bio offset + size.
771 *
772 **/
773 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
774 u32 what, int error)
775 {
776 struct blk_trace *bt = q->blk_trace;
777
778 if (likely(!bt))
779 return;
780
781 if (!error && !bio_flagged(bio, BIO_UPTODATE))
782 error = EIO;
783
784 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
785 bio->bi_rw, what, error, 0, NULL);
786 }
787
788 static void blk_add_trace_bio_bounce(void *ignore,
789 struct request_queue *q, struct bio *bio)
790 {
791 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
792 }
793
794 static void blk_add_trace_bio_complete(void *ignore,
795 struct request_queue *q, struct bio *bio,
796 int error)
797 {
798 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
799 }
800
801 static void blk_add_trace_bio_backmerge(void *ignore,
802 struct request_queue *q,
803 struct request *rq,
804 struct bio *bio)
805 {
806 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
807 }
808
809 static void blk_add_trace_bio_frontmerge(void *ignore,
810 struct request_queue *q,
811 struct request *rq,
812 struct bio *bio)
813 {
814 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
815 }
816
817 static void blk_add_trace_bio_queue(void *ignore,
818 struct request_queue *q, struct bio *bio)
819 {
820 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
821 }
822
823 static void blk_add_trace_getrq(void *ignore,
824 struct request_queue *q,
825 struct bio *bio, int rw)
826 {
827 if (bio)
828 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
829 else {
830 struct blk_trace *bt = q->blk_trace;
831
832 if (bt)
833 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
834 }
835 }
836
837
838 static void blk_add_trace_sleeprq(void *ignore,
839 struct request_queue *q,
840 struct bio *bio, int rw)
841 {
842 if (bio)
843 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
844 else {
845 struct blk_trace *bt = q->blk_trace;
846
847 if (bt)
848 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
849 0, 0, NULL);
850 }
851 }
852
853 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
854 {
855 struct blk_trace *bt = q->blk_trace;
856
857 if (bt)
858 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
859 }
860
861 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
862 unsigned int depth, bool explicit)
863 {
864 struct blk_trace *bt = q->blk_trace;
865
866 if (bt) {
867 __be64 rpdu = cpu_to_be64(depth);
868 u32 what;
869
870 if (explicit)
871 what = BLK_TA_UNPLUG_IO;
872 else
873 what = BLK_TA_UNPLUG_TIMER;
874
875 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
876 }
877 }
878
879 static void blk_add_trace_split(void *ignore,
880 struct request_queue *q, struct bio *bio,
881 unsigned int pdu)
882 {
883 struct blk_trace *bt = q->blk_trace;
884
885 if (bt) {
886 __be64 rpdu = cpu_to_be64(pdu);
887
888 __blk_add_trace(bt, bio->bi_iter.bi_sector,
889 bio->bi_iter.bi_size, bio->bi_rw, BLK_TA_SPLIT,
890 !bio_flagged(bio, BIO_UPTODATE),
891 sizeof(rpdu), &rpdu);
892 }
893 }
894
895 /**
896 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
897 * @ignore: trace callback data parameter (not used)
898 * @q: queue the io is for
899 * @bio: the source bio
900 * @dev: target device
901 * @from: source sector
902 *
903 * Description:
904 * Device mapper or raid target sometimes need to split a bio because
905 * it spans a stripe (or similar). Add a trace for that action.
906 *
907 **/
908 static void blk_add_trace_bio_remap(void *ignore,
909 struct request_queue *q, struct bio *bio,
910 dev_t dev, sector_t from)
911 {
912 struct blk_trace *bt = q->blk_trace;
913 struct blk_io_trace_remap r;
914
915 if (likely(!bt))
916 return;
917
918 r.device_from = cpu_to_be32(dev);
919 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
920 r.sector_from = cpu_to_be64(from);
921
922 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
923 bio->bi_rw, BLK_TA_REMAP,
924 !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
925 }
926
927 /**
928 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
929 * @ignore: trace callback data parameter (not used)
930 * @q: queue the io is for
931 * @rq: the source request
932 * @dev: target device
933 * @from: source sector
934 *
935 * Description:
936 * Device mapper remaps request to other devices.
937 * Add a trace for that action.
938 *
939 **/
940 static void blk_add_trace_rq_remap(void *ignore,
941 struct request_queue *q,
942 struct request *rq, dev_t dev,
943 sector_t from)
944 {
945 struct blk_trace *bt = q->blk_trace;
946 struct blk_io_trace_remap r;
947
948 if (likely(!bt))
949 return;
950
951 r.device_from = cpu_to_be32(dev);
952 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
953 r.sector_from = cpu_to_be64(from);
954
955 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
956 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
957 sizeof(r), &r);
958 }
959
960 /**
961 * blk_add_driver_data - Add binary message with driver-specific data
962 * @q: queue the io is for
963 * @rq: io request
964 * @data: driver-specific data
965 * @len: length of driver-specific data
966 *
967 * Description:
968 * Some drivers might want to write driver-specific data per request.
969 *
970 **/
971 void blk_add_driver_data(struct request_queue *q,
972 struct request *rq,
973 void *data, size_t len)
974 {
975 struct blk_trace *bt = q->blk_trace;
976
977 if (likely(!bt))
978 return;
979
980 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
981 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
982 BLK_TA_DRV_DATA, rq->errors, len, data);
983 else
984 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
985 BLK_TA_DRV_DATA, rq->errors, len, data);
986 }
987 EXPORT_SYMBOL_GPL(blk_add_driver_data);
988
989 static void blk_register_tracepoints(void)
990 {
991 int ret;
992
993 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
994 WARN_ON(ret);
995 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1006 WARN_ON(ret);
1007 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1008 WARN_ON(ret);
1009 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1010 WARN_ON(ret);
1011 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1012 WARN_ON(ret);
1013 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1014 WARN_ON(ret);
1015 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1016 WARN_ON(ret);
1017 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1018 WARN_ON(ret);
1019 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1020 WARN_ON(ret);
1021 ret = register_trace_block_split(blk_add_trace_split, NULL);
1022 WARN_ON(ret);
1023 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1024 WARN_ON(ret);
1025 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1026 WARN_ON(ret);
1027 }
1028
1029 static void blk_unregister_tracepoints(void)
1030 {
1031 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1032 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1033 unregister_trace_block_split(blk_add_trace_split, NULL);
1034 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1035 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1036 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1037 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1038 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1039 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1040 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1041 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1042 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1043 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1044 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1045 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1046 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1047 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1048
1049 tracepoint_synchronize_unregister();
1050 }
1051
1052 /*
1053 * struct blk_io_tracer formatting routines
1054 */
1055
1056 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1057 {
1058 int i = 0;
1059 int tc = t->action >> BLK_TC_SHIFT;
1060
1061 if (t->action == BLK_TN_MESSAGE) {
1062 rwbs[i++] = 'N';
1063 goto out;
1064 }
1065
1066 if (tc & BLK_TC_FLUSH)
1067 rwbs[i++] = 'F';
1068
1069 if (tc & BLK_TC_DISCARD)
1070 rwbs[i++] = 'D';
1071 else if (tc & BLK_TC_WRITE)
1072 rwbs[i++] = 'W';
1073 else if (t->bytes)
1074 rwbs[i++] = 'R';
1075 else
1076 rwbs[i++] = 'N';
1077
1078 if (tc & BLK_TC_FUA)
1079 rwbs[i++] = 'F';
1080 if (tc & BLK_TC_AHEAD)
1081 rwbs[i++] = 'A';
1082 if (tc & BLK_TC_SYNC)
1083 rwbs[i++] = 'S';
1084 if (tc & BLK_TC_META)
1085 rwbs[i++] = 'M';
1086 out:
1087 rwbs[i] = '\0';
1088 }
1089
1090 static inline
1091 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1092 {
1093 return (const struct blk_io_trace *)ent;
1094 }
1095
1096 static inline const void *pdu_start(const struct trace_entry *ent)
1097 {
1098 return te_blk_io_trace(ent) + 1;
1099 }
1100
1101 static inline u32 t_action(const struct trace_entry *ent)
1102 {
1103 return te_blk_io_trace(ent)->action;
1104 }
1105
1106 static inline u32 t_bytes(const struct trace_entry *ent)
1107 {
1108 return te_blk_io_trace(ent)->bytes;
1109 }
1110
1111 static inline u32 t_sec(const struct trace_entry *ent)
1112 {
1113 return te_blk_io_trace(ent)->bytes >> 9;
1114 }
1115
1116 static inline unsigned long long t_sector(const struct trace_entry *ent)
1117 {
1118 return te_blk_io_trace(ent)->sector;
1119 }
1120
1121 static inline __u16 t_error(const struct trace_entry *ent)
1122 {
1123 return te_blk_io_trace(ent)->error;
1124 }
1125
1126 static __u64 get_pdu_int(const struct trace_entry *ent)
1127 {
1128 const __u64 *val = pdu_start(ent);
1129 return be64_to_cpu(*val);
1130 }
1131
1132 static void get_pdu_remap(const struct trace_entry *ent,
1133 struct blk_io_trace_remap *r)
1134 {
1135 const struct blk_io_trace_remap *__r = pdu_start(ent);
1136 __u64 sector_from = __r->sector_from;
1137
1138 r->device_from = be32_to_cpu(__r->device_from);
1139 r->device_to = be32_to_cpu(__r->device_to);
1140 r->sector_from = be64_to_cpu(sector_from);
1141 }
1142
1143 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1144
1145 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1146 {
1147 char rwbs[RWBS_LEN];
1148 unsigned long long ts = iter->ts;
1149 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1150 unsigned secs = (unsigned long)ts;
1151 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1152
1153 fill_rwbs(rwbs, t);
1154
1155 return trace_seq_printf(&iter->seq,
1156 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1157 MAJOR(t->device), MINOR(t->device), iter->cpu,
1158 secs, nsec_rem, iter->ent->pid, act, rwbs);
1159 }
1160
1161 static int blk_log_action(struct trace_iterator *iter, const char *act)
1162 {
1163 char rwbs[RWBS_LEN];
1164 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1165
1166 fill_rwbs(rwbs, t);
1167 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1168 MAJOR(t->device), MINOR(t->device), act, rwbs);
1169 }
1170
1171 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1172 {
1173 const unsigned char *pdu_buf;
1174 int pdu_len;
1175 int i, end, ret;
1176
1177 pdu_buf = pdu_start(ent);
1178 pdu_len = te_blk_io_trace(ent)->pdu_len;
1179
1180 if (!pdu_len)
1181 return 1;
1182
1183 /* find the last zero that needs to be printed */
1184 for (end = pdu_len - 1; end >= 0; end--)
1185 if (pdu_buf[end])
1186 break;
1187 end++;
1188
1189 if (!trace_seq_putc(s, '('))
1190 return 0;
1191
1192 for (i = 0; i < pdu_len; i++) {
1193
1194 ret = trace_seq_printf(s, "%s%02x",
1195 i == 0 ? "" : " ", pdu_buf[i]);
1196 if (!ret)
1197 return ret;
1198
1199 /*
1200 * stop when the rest is just zeroes and indicate so
1201 * with a ".." appended
1202 */
1203 if (i == end && end != pdu_len - 1)
1204 return trace_seq_puts(s, " ..) ");
1205 }
1206
1207 return trace_seq_puts(s, ") ");
1208 }
1209
1210 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1211 {
1212 char cmd[TASK_COMM_LEN];
1213
1214 trace_find_cmdline(ent->pid, cmd);
1215
1216 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1217 int ret;
1218
1219 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1220 if (!ret)
1221 return 0;
1222 ret = blk_log_dump_pdu(s, ent);
1223 if (!ret)
1224 return 0;
1225 return trace_seq_printf(s, "[%s]\n", cmd);
1226 } else {
1227 if (t_sec(ent))
1228 return trace_seq_printf(s, "%llu + %u [%s]\n",
1229 t_sector(ent), t_sec(ent), cmd);
1230 return trace_seq_printf(s, "[%s]\n", cmd);
1231 }
1232 }
1233
1234 static int blk_log_with_error(struct trace_seq *s,
1235 const struct trace_entry *ent)
1236 {
1237 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1238 int ret;
1239
1240 ret = blk_log_dump_pdu(s, ent);
1241 if (ret)
1242 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1243 return 0;
1244 } else {
1245 if (t_sec(ent))
1246 return trace_seq_printf(s, "%llu + %u [%d]\n",
1247 t_sector(ent),
1248 t_sec(ent), t_error(ent));
1249 return trace_seq_printf(s, "%llu [%d]\n",
1250 t_sector(ent), t_error(ent));
1251 }
1252 }
1253
1254 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1255 {
1256 struct blk_io_trace_remap r = { .device_from = 0, };
1257
1258 get_pdu_remap(ent, &r);
1259 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1260 t_sector(ent), t_sec(ent),
1261 MAJOR(r.device_from), MINOR(r.device_from),
1262 (unsigned long long)r.sector_from);
1263 }
1264
1265 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1266 {
1267 char cmd[TASK_COMM_LEN];
1268
1269 trace_find_cmdline(ent->pid, cmd);
1270
1271 return trace_seq_printf(s, "[%s]\n", cmd);
1272 }
1273
1274 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1275 {
1276 char cmd[TASK_COMM_LEN];
1277
1278 trace_find_cmdline(ent->pid, cmd);
1279
1280 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1281 }
1282
1283 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1284 {
1285 char cmd[TASK_COMM_LEN];
1286
1287 trace_find_cmdline(ent->pid, cmd);
1288
1289 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1290 get_pdu_int(ent), cmd);
1291 }
1292
1293 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1294 {
1295 int ret;
1296 const struct blk_io_trace *t = te_blk_io_trace(ent);
1297
1298 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1299 if (ret)
1300 return trace_seq_putc(s, '\n');
1301 return ret;
1302 }
1303
1304 /*
1305 * struct tracer operations
1306 */
1307
1308 static void blk_tracer_print_header(struct seq_file *m)
1309 {
1310 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1311 return;
1312 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1313 "# | | | | | |\n");
1314 }
1315
1316 static void blk_tracer_start(struct trace_array *tr)
1317 {
1318 blk_tracer_enabled = true;
1319 }
1320
1321 static int blk_tracer_init(struct trace_array *tr)
1322 {
1323 blk_tr = tr;
1324 blk_tracer_start(tr);
1325 return 0;
1326 }
1327
1328 static void blk_tracer_stop(struct trace_array *tr)
1329 {
1330 blk_tracer_enabled = false;
1331 }
1332
1333 static void blk_tracer_reset(struct trace_array *tr)
1334 {
1335 blk_tracer_stop(tr);
1336 }
1337
1338 static const struct {
1339 const char *act[2];
1340 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1341 } what2act[] = {
1342 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1343 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1344 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1345 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1346 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1347 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1348 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1349 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1350 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1351 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1352 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1353 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1354 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1355 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1356 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1357 };
1358
1359 static enum print_line_t print_one_line(struct trace_iterator *iter,
1360 bool classic)
1361 {
1362 struct trace_seq *s = &iter->seq;
1363 const struct blk_io_trace *t;
1364 u16 what;
1365 int ret;
1366 bool long_act;
1367 blk_log_action_t *log_action;
1368
1369 t = te_blk_io_trace(iter->ent);
1370 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1371 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1372 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1373
1374 if (t->action == BLK_TN_MESSAGE) {
1375 ret = log_action(iter, long_act ? "message" : "m");
1376 if (ret)
1377 ret = blk_log_msg(s, iter->ent);
1378 goto out;
1379 }
1380
1381 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1382 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1383 else {
1384 ret = log_action(iter, what2act[what].act[long_act]);
1385 if (ret)
1386 ret = what2act[what].print(s, iter->ent);
1387 }
1388 out:
1389 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1390 }
1391
1392 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1393 int flags, struct trace_event *event)
1394 {
1395 return print_one_line(iter, false);
1396 }
1397
1398 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1399 {
1400 struct trace_seq *s = &iter->seq;
1401 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1402 const int offset = offsetof(struct blk_io_trace, sector);
1403 struct blk_io_trace old = {
1404 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1405 .time = iter->ts,
1406 };
1407
1408 if (!trace_seq_putmem(s, &old, offset))
1409 return 0;
1410 return trace_seq_putmem(s, &t->sector,
1411 sizeof(old) - offset + t->pdu_len);
1412 }
1413
1414 static enum print_line_t
1415 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1416 struct trace_event *event)
1417 {
1418 return blk_trace_synthesize_old_trace(iter) ?
1419 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1420 }
1421
1422 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1423 {
1424 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1425 return TRACE_TYPE_UNHANDLED;
1426
1427 return print_one_line(iter, true);
1428 }
1429
1430 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1431 {
1432 /* don't output context-info for blk_classic output */
1433 if (bit == TRACE_BLK_OPT_CLASSIC) {
1434 if (set)
1435 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1436 else
1437 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1438 }
1439 return 0;
1440 }
1441
1442 static struct tracer blk_tracer __read_mostly = {
1443 .name = "blk",
1444 .init = blk_tracer_init,
1445 .reset = blk_tracer_reset,
1446 .start = blk_tracer_start,
1447 .stop = blk_tracer_stop,
1448 .print_header = blk_tracer_print_header,
1449 .print_line = blk_tracer_print_line,
1450 .flags = &blk_tracer_flags,
1451 .set_flag = blk_tracer_set_flag,
1452 };
1453
1454 static struct trace_event_functions trace_blk_event_funcs = {
1455 .trace = blk_trace_event_print,
1456 .binary = blk_trace_event_print_binary,
1457 };
1458
1459 static struct trace_event trace_blk_event = {
1460 .type = TRACE_BLK,
1461 .funcs = &trace_blk_event_funcs,
1462 };
1463
1464 static int __init init_blk_tracer(void)
1465 {
1466 if (!register_ftrace_event(&trace_blk_event)) {
1467 pr_warning("Warning: could not register block events\n");
1468 return 1;
1469 }
1470
1471 if (register_tracer(&blk_tracer) != 0) {
1472 pr_warning("Warning: could not register the block tracer\n");
1473 unregister_ftrace_event(&trace_blk_event);
1474 return 1;
1475 }
1476
1477 return 0;
1478 }
1479
1480 device_initcall(init_blk_tracer);
1481
1482 static int blk_trace_remove_queue(struct request_queue *q)
1483 {
1484 struct blk_trace *bt;
1485
1486 bt = xchg(&q->blk_trace, NULL);
1487 if (bt == NULL)
1488 return -EINVAL;
1489
1490 if (atomic_dec_and_test(&blk_probes_ref))
1491 blk_unregister_tracepoints();
1492
1493 spin_lock_irq(&running_trace_lock);
1494 list_del(&bt->running_list);
1495 spin_unlock_irq(&running_trace_lock);
1496 blk_trace_free(bt);
1497 return 0;
1498 }
1499
1500 /*
1501 * Setup everything required to start tracing
1502 */
1503 static int blk_trace_setup_queue(struct request_queue *q,
1504 struct block_device *bdev)
1505 {
1506 struct blk_trace *old_bt, *bt = NULL;
1507 int ret = -ENOMEM;
1508
1509 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1510 if (!bt)
1511 return -ENOMEM;
1512
1513 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1514 if (!bt->msg_data)
1515 goto free_bt;
1516
1517 bt->dev = bdev->bd_dev;
1518 bt->act_mask = (u16)-1;
1519
1520 blk_trace_setup_lba(bt, bdev);
1521
1522 old_bt = xchg(&q->blk_trace, bt);
1523 if (old_bt != NULL) {
1524 (void)xchg(&q->blk_trace, old_bt);
1525 ret = -EBUSY;
1526 goto free_bt;
1527 }
1528
1529 if (atomic_inc_return(&blk_probes_ref) == 1)
1530 blk_register_tracepoints();
1531 return 0;
1532
1533 free_bt:
1534 blk_trace_free(bt);
1535 return ret;
1536 }
1537
1538 /*
1539 * sysfs interface to enable and configure tracing
1540 */
1541
1542 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1543 struct device_attribute *attr,
1544 char *buf);
1545 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1546 struct device_attribute *attr,
1547 const char *buf, size_t count);
1548 #define BLK_TRACE_DEVICE_ATTR(_name) \
1549 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1550 sysfs_blk_trace_attr_show, \
1551 sysfs_blk_trace_attr_store)
1552
1553 static BLK_TRACE_DEVICE_ATTR(enable);
1554 static BLK_TRACE_DEVICE_ATTR(act_mask);
1555 static BLK_TRACE_DEVICE_ATTR(pid);
1556 static BLK_TRACE_DEVICE_ATTR(start_lba);
1557 static BLK_TRACE_DEVICE_ATTR(end_lba);
1558
1559 static struct attribute *blk_trace_attrs[] = {
1560 &dev_attr_enable.attr,
1561 &dev_attr_act_mask.attr,
1562 &dev_attr_pid.attr,
1563 &dev_attr_start_lba.attr,
1564 &dev_attr_end_lba.attr,
1565 NULL
1566 };
1567
1568 struct attribute_group blk_trace_attr_group = {
1569 .name = "trace",
1570 .attrs = blk_trace_attrs,
1571 };
1572
1573 static const struct {
1574 int mask;
1575 const char *str;
1576 } mask_maps[] = {
1577 { BLK_TC_READ, "read" },
1578 { BLK_TC_WRITE, "write" },
1579 { BLK_TC_FLUSH, "flush" },
1580 { BLK_TC_SYNC, "sync" },
1581 { BLK_TC_QUEUE, "queue" },
1582 { BLK_TC_REQUEUE, "requeue" },
1583 { BLK_TC_ISSUE, "issue" },
1584 { BLK_TC_COMPLETE, "complete" },
1585 { BLK_TC_FS, "fs" },
1586 { BLK_TC_PC, "pc" },
1587 { BLK_TC_AHEAD, "ahead" },
1588 { BLK_TC_META, "meta" },
1589 { BLK_TC_DISCARD, "discard" },
1590 { BLK_TC_DRV_DATA, "drv_data" },
1591 { BLK_TC_FUA, "fua" },
1592 };
1593
1594 static int blk_trace_str2mask(const char *str)
1595 {
1596 int i;
1597 int mask = 0;
1598 char *buf, *s, *token;
1599
1600 buf = kstrdup(str, GFP_KERNEL);
1601 if (buf == NULL)
1602 return -ENOMEM;
1603 s = strstrip(buf);
1604
1605 while (1) {
1606 token = strsep(&s, ",");
1607 if (token == NULL)
1608 break;
1609
1610 if (*token == '\0')
1611 continue;
1612
1613 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1614 if (strcasecmp(token, mask_maps[i].str) == 0) {
1615 mask |= mask_maps[i].mask;
1616 break;
1617 }
1618 }
1619 if (i == ARRAY_SIZE(mask_maps)) {
1620 mask = -EINVAL;
1621 break;
1622 }
1623 }
1624 kfree(buf);
1625
1626 return mask;
1627 }
1628
1629 static ssize_t blk_trace_mask2str(char *buf, int mask)
1630 {
1631 int i;
1632 char *p = buf;
1633
1634 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1635 if (mask & mask_maps[i].mask) {
1636 p += sprintf(p, "%s%s",
1637 (p == buf) ? "" : ",", mask_maps[i].str);
1638 }
1639 }
1640 *p++ = '\n';
1641
1642 return p - buf;
1643 }
1644
1645 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1646 {
1647 if (bdev->bd_disk == NULL)
1648 return NULL;
1649
1650 return bdev_get_queue(bdev);
1651 }
1652
1653 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1654 struct device_attribute *attr,
1655 char *buf)
1656 {
1657 struct hd_struct *p = dev_to_part(dev);
1658 struct request_queue *q;
1659 struct block_device *bdev;
1660 ssize_t ret = -ENXIO;
1661
1662 bdev = bdget(part_devt(p));
1663 if (bdev == NULL)
1664 goto out;
1665
1666 q = blk_trace_get_queue(bdev);
1667 if (q == NULL)
1668 goto out_bdput;
1669
1670 mutex_lock(&bdev->bd_mutex);
1671
1672 if (attr == &dev_attr_enable) {
1673 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1674 goto out_unlock_bdev;
1675 }
1676
1677 if (q->blk_trace == NULL)
1678 ret = sprintf(buf, "disabled\n");
1679 else if (attr == &dev_attr_act_mask)
1680 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1681 else if (attr == &dev_attr_pid)
1682 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1683 else if (attr == &dev_attr_start_lba)
1684 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1685 else if (attr == &dev_attr_end_lba)
1686 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1687
1688 out_unlock_bdev:
1689 mutex_unlock(&bdev->bd_mutex);
1690 out_bdput:
1691 bdput(bdev);
1692 out:
1693 return ret;
1694 }
1695
1696 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1697 struct device_attribute *attr,
1698 const char *buf, size_t count)
1699 {
1700 struct block_device *bdev;
1701 struct request_queue *q;
1702 struct hd_struct *p;
1703 u64 value;
1704 ssize_t ret = -EINVAL;
1705
1706 if (count == 0)
1707 goto out;
1708
1709 if (attr == &dev_attr_act_mask) {
1710 if (sscanf(buf, "%llx", &value) != 1) {
1711 /* Assume it is a list of trace category names */
1712 ret = blk_trace_str2mask(buf);
1713 if (ret < 0)
1714 goto out;
1715 value = ret;
1716 }
1717 } else if (sscanf(buf, "%llu", &value) != 1)
1718 goto out;
1719
1720 ret = -ENXIO;
1721
1722 p = dev_to_part(dev);
1723 bdev = bdget(part_devt(p));
1724 if (bdev == NULL)
1725 goto out;
1726
1727 q = blk_trace_get_queue(bdev);
1728 if (q == NULL)
1729 goto out_bdput;
1730
1731 mutex_lock(&bdev->bd_mutex);
1732
1733 if (attr == &dev_attr_enable) {
1734 if (value)
1735 ret = blk_trace_setup_queue(q, bdev);
1736 else
1737 ret = blk_trace_remove_queue(q);
1738 goto out_unlock_bdev;
1739 }
1740
1741 ret = 0;
1742 if (q->blk_trace == NULL)
1743 ret = blk_trace_setup_queue(q, bdev);
1744
1745 if (ret == 0) {
1746 if (attr == &dev_attr_act_mask)
1747 q->blk_trace->act_mask = value;
1748 else if (attr == &dev_attr_pid)
1749 q->blk_trace->pid = value;
1750 else if (attr == &dev_attr_start_lba)
1751 q->blk_trace->start_lba = value;
1752 else if (attr == &dev_attr_end_lba)
1753 q->blk_trace->end_lba = value;
1754 }
1755
1756 out_unlock_bdev:
1757 mutex_unlock(&bdev->bd_mutex);
1758 out_bdput:
1759 bdput(bdev);
1760 out:
1761 return ret ? ret : count;
1762 }
1763
1764 int blk_trace_init_sysfs(struct device *dev)
1765 {
1766 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1767 }
1768
1769 void blk_trace_remove_sysfs(struct device *dev)
1770 {
1771 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1772 }
1773
1774 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1775
1776 #ifdef CONFIG_EVENT_TRACING
1777
1778 void blk_dump_cmd(char *buf, struct request *rq)
1779 {
1780 int i, end;
1781 int len = rq->cmd_len;
1782 unsigned char *cmd = rq->cmd;
1783
1784 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1785 buf[0] = '\0';
1786 return;
1787 }
1788
1789 for (end = len - 1; end >= 0; end--)
1790 if (cmd[end])
1791 break;
1792 end++;
1793
1794 for (i = 0; i < len; i++) {
1795 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1796 if (i == end && end != len - 1) {
1797 sprintf(buf, " ..");
1798 break;
1799 }
1800 }
1801 }
1802
1803 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1804 {
1805 int i = 0;
1806
1807 if (rw & REQ_FLUSH)
1808 rwbs[i++] = 'F';
1809
1810 if (rw & WRITE)
1811 rwbs[i++] = 'W';
1812 else if (rw & REQ_DISCARD)
1813 rwbs[i++] = 'D';
1814 else if (bytes)
1815 rwbs[i++] = 'R';
1816 else
1817 rwbs[i++] = 'N';
1818
1819 if (rw & REQ_FUA)
1820 rwbs[i++] = 'F';
1821 if (rw & REQ_RAHEAD)
1822 rwbs[i++] = 'A';
1823 if (rw & REQ_SYNC)
1824 rwbs[i++] = 'S';
1825 if (rw & REQ_META)
1826 rwbs[i++] = 'M';
1827 if (rw & REQ_SECURE)
1828 rwbs[i++] = 'E';
1829
1830 rwbs[i] = '\0';
1831 }
1832 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1833
1834 #endif /* CONFIG_EVENT_TRACING */
1835
Linux with added FPC-III support