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agp: kill agp_rebind_memory
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / trace / blktrace.c
blob7b8ec02815482773bc0eccb3918e207934f46419
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
35 static unsigned int blktrace_seq __read_mostly = 1;
36
37 static struct trace_array *blk_tr;
38 static 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
43 static struct tracer_opt blk_tracer_opts[] = {
44 /* Default disable the minimalistic output */
45 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
46 { }
47 };
48
49 static struct tracer_flags blk_tracer_flags = {
50 .val = 0,
51 .opts = blk_tracer_opts,
52 };
53
54 /* Global reference count of probes */
55 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
56
57 static void blk_register_tracepoints(void);
58 static void blk_unregister_tracepoints(void);
59
60 /*
61 * Send out a notify message.
62 */
63 static 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());
92 record_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 */
109 static 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
115 static 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
130 void __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 local_irq_save(flags);
142 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
143 va_start(args, fmt);
144 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
145 va_end(args);
146
147 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
148 local_irq_restore(flags);
149 }
150 EXPORT_SYMBOL_GPL(__trace_note_message);
151
152 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
153 pid_t pid)
154 {
155 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
156 return 1;
157 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
158 return 1;
159 if (bt->pid && pid != bt->pid)
160 return 1;
161
162 return 0;
163 }
164
165 /*
166 * Data direction bit lookup
167 */
168 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
169 BLK_TC_ACT(BLK_TC_WRITE) };
170
171 #define BLK_TC_RAHEAD BLK_TC_AHEAD
172
173 /* The ilog2() calls fall out because they're constant */
174 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
175 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
176
177 /*
178 * The worker for the various blk_add_trace*() types. Fills out a
179 * blk_io_trace structure and places it in a per-cpu subbuffer.
180 */
181 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
182 int rw, u32 what, int error, int pdu_len, void *pdu_data)
183 {
184 struct task_struct *tsk = current;
185 struct ring_buffer_event *event = NULL;
186 struct ring_buffer *buffer = NULL;
187 struct blk_io_trace *t;
188 unsigned long flags = 0;
189 unsigned long *sequence;
190 pid_t pid;
191 int cpu, pc = 0;
192 bool blk_tracer = blk_tracer_enabled;
193
194 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
195 return;
196
197 what |= ddir_act[rw & WRITE];
198 what |= MASK_TC_BIT(rw, SYNC);
199 what |= MASK_TC_BIT(rw, RAHEAD);
200 what |= MASK_TC_BIT(rw, META);
201 what |= MASK_TC_BIT(rw, DISCARD);
202
203 pid = tsk->pid;
204 if (act_log_check(bt, what, sector, pid))
205 return;
206 cpu = raw_smp_processor_id();
207
208 if (blk_tracer) {
209 tracing_record_cmdline(current);
210
211 buffer = blk_tr->buffer;
212 pc = preempt_count();
213 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
214 sizeof(*t) + pdu_len,
215 0, pc);
216 if (!event)
217 return;
218 t = ring_buffer_event_data(event);
219 goto record_it;
220 }
221
222 /*
223 * A word about the locking here - we disable interrupts to reserve
224 * some space in the relay per-cpu buffer, to prevent an irq
225 * from coming in and stepping on our toes.
226 */
227 local_irq_save(flags);
228
229 if (unlikely(tsk->btrace_seq != blktrace_seq))
230 trace_note_tsk(bt, tsk);
231
232 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
233 if (t) {
234 sequence = per_cpu_ptr(bt->sequence, cpu);
235
236 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
237 t->sequence = ++(*sequence);
238 t->time = ktime_to_ns(ktime_get());
239 record_it:
240 /*
241 * These two are not needed in ftrace as they are in the
242 * generic trace_entry, filled by tracing_generic_entry_update,
243 * but for the trace_event->bin() synthesizer benefit we do it
244 * here too.
245 */
246 t->cpu = cpu;
247 t->pid = pid;
248
249 t->sector = sector;
250 t->bytes = bytes;
251 t->action = what;
252 t->device = bt->dev;
253 t->error = error;
254 t->pdu_len = pdu_len;
255
256 if (pdu_len)
257 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
258
259 if (blk_tracer) {
260 trace_buffer_unlock_commit(buffer, event, 0, pc);
261 return;
262 }
263 }
264
265 local_irq_restore(flags);
266 }
267
268 static struct dentry *blk_tree_root;
269 static DEFINE_MUTEX(blk_tree_mutex);
270
271 static void blk_trace_free(struct blk_trace *bt)
272 {
273 debugfs_remove(bt->msg_file);
274 debugfs_remove(bt->dropped_file);
275 relay_close(bt->rchan);
276 debugfs_remove(bt->dir);
277 free_percpu(bt->sequence);
278 free_percpu(bt->msg_data);
279 kfree(bt);
280 }
281
282 static void blk_trace_cleanup(struct blk_trace *bt)
283 {
284 blk_trace_free(bt);
285 if (atomic_dec_and_test(&blk_probes_ref))
286 blk_unregister_tracepoints();
287 }
288
289 int blk_trace_remove(struct request_queue *q)
290 {
291 struct blk_trace *bt;
292
293 bt = xchg(&q->blk_trace, NULL);
294 if (!bt)
295 return -EINVAL;
296
297 if (bt->trace_state != Blktrace_running)
298 blk_trace_cleanup(bt);
299
300 return 0;
301 }
302 EXPORT_SYMBOL_GPL(blk_trace_remove);
303
304 static int blk_dropped_open(struct inode *inode, struct file *filp)
305 {
306 filp->private_data = inode->i_private;
307
308 return 0;
309 }
310
311 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
312 size_t count, loff_t *ppos)
313 {
314 struct blk_trace *bt = filp->private_data;
315 char buf[16];
316
317 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
318
319 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
320 }
321
322 static const struct file_operations blk_dropped_fops = {
323 .owner = THIS_MODULE,
324 .open = blk_dropped_open,
325 .read = blk_dropped_read,
326 .llseek = default_llseek,
327 };
328
329 static int blk_msg_open(struct inode *inode, struct file *filp)
330 {
331 filp->private_data = inode->i_private;
332
333 return 0;
334 }
335
336 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
337 size_t count, loff_t *ppos)
338 {
339 char *msg;
340 struct blk_trace *bt;
341
342 if (count >= BLK_TN_MAX_MSG)
343 return -EINVAL;
344
345 msg = kmalloc(count + 1, GFP_KERNEL);
346 if (msg == NULL)
347 return -ENOMEM;
348
349 if (copy_from_user(msg, buffer, count)) {
350 kfree(msg);
351 return -EFAULT;
352 }
353
354 msg[count] = '\0';
355 bt = filp->private_data;
356 __trace_note_message(bt, "%s", msg);
357 kfree(msg);
358
359 return count;
360 }
361
362 static const struct file_operations blk_msg_fops = {
363 .owner = THIS_MODULE,
364 .open = blk_msg_open,
365 .write = blk_msg_write,
366 .llseek = noop_llseek,
367 };
368
369 /*
370 * Keep track of how many times we encountered a full subbuffer, to aid
371 * the user space app in telling how many lost events there were.
372 */
373 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
374 void *prev_subbuf, size_t prev_padding)
375 {
376 struct blk_trace *bt;
377
378 if (!relay_buf_full(buf))
379 return 1;
380
381 bt = buf->chan->private_data;
382 atomic_inc(&bt->dropped);
383 return 0;
384 }
385
386 static int blk_remove_buf_file_callback(struct dentry *dentry)
387 {
388 debugfs_remove(dentry);
389
390 return 0;
391 }
392
393 static struct dentry *blk_create_buf_file_callback(const char *filename,
394 struct dentry *parent,
395 int mode,
396 struct rchan_buf *buf,
397 int *is_global)
398 {
399 return debugfs_create_file(filename, mode, parent, buf,
400 &relay_file_operations);
401 }
402
403 static struct rchan_callbacks blk_relay_callbacks = {
404 .subbuf_start = blk_subbuf_start_callback,
405 .create_buf_file = blk_create_buf_file_callback,
406 .remove_buf_file = blk_remove_buf_file_callback,
407 };
408
409 static void blk_trace_setup_lba(struct blk_trace *bt,
410 struct block_device *bdev)
411 {
412 struct hd_struct *part = NULL;
413
414 if (bdev)
415 part = bdev->bd_part;
416
417 if (part) {
418 bt->start_lba = part->start_sect;
419 bt->end_lba = part->start_sect + part->nr_sects;
420 } else {
421 bt->start_lba = 0;
422 bt->end_lba = -1ULL;
423 }
424 }
425
426 /*
427 * Setup everything required to start tracing
428 */
429 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
430 struct block_device *bdev,
431 struct blk_user_trace_setup *buts)
432 {
433 struct blk_trace *old_bt, *bt = NULL;
434 struct dentry *dir = NULL;
435 int ret, i;
436
437 if (!buts->buf_size || !buts->buf_nr)
438 return -EINVAL;
439
440 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
441 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
442
443 /*
444 * some device names have larger paths - convert the slashes
445 * to underscores for this to work as expected
446 */
447 for (i = 0; i < strlen(buts->name); i++)
448 if (buts->name[i] == '/')
449 buts->name[i] = '_';
450
451 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
452 if (!bt)
453 return -ENOMEM;
454
455 ret = -ENOMEM;
456 bt->sequence = alloc_percpu(unsigned long);
457 if (!bt->sequence)
458 goto err;
459
460 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
461 if (!bt->msg_data)
462 goto err;
463
464 ret = -ENOENT;
465
466 mutex_lock(&blk_tree_mutex);
467 if (!blk_tree_root) {
468 blk_tree_root = debugfs_create_dir("block", NULL);
469 if (!blk_tree_root) {
470 mutex_unlock(&blk_tree_mutex);
471 goto err;
472 }
473 }
474 mutex_unlock(&blk_tree_mutex);
475
476 dir = debugfs_create_dir(buts->name, blk_tree_root);
477
478 if (!dir)
479 goto err;
480
481 bt->dir = dir;
482 bt->dev = dev;
483 atomic_set(&bt->dropped, 0);
484
485 ret = -EIO;
486 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
487 &blk_dropped_fops);
488 if (!bt->dropped_file)
489 goto err;
490
491 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
492 if (!bt->msg_file)
493 goto err;
494
495 bt->rchan = relay_open("trace", dir, buts->buf_size,
496 buts->buf_nr, &blk_relay_callbacks, bt);
497 if (!bt->rchan)
498 goto err;
499
500 bt->act_mask = buts->act_mask;
501 if (!bt->act_mask)
502 bt->act_mask = (u16) -1;
503
504 blk_trace_setup_lba(bt, bdev);
505
506 /* overwrite with user settings */
507 if (buts->start_lba)
508 bt->start_lba = buts->start_lba;
509 if (buts->end_lba)
510 bt->end_lba = buts->end_lba;
511
512 bt->pid = buts->pid;
513 bt->trace_state = Blktrace_setup;
514
515 ret = -EBUSY;
516 old_bt = xchg(&q->blk_trace, bt);
517 if (old_bt) {
518 (void) xchg(&q->blk_trace, old_bt);
519 goto err;
520 }
521
522 if (atomic_inc_return(&blk_probes_ref) == 1)
523 blk_register_tracepoints();
524
525 return 0;
526 err:
527 blk_trace_free(bt);
528 return ret;
529 }
530
531 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
532 struct block_device *bdev,
533 char __user *arg)
534 {
535 struct blk_user_trace_setup buts;
536 int ret;
537
538 ret = copy_from_user(&buts, arg, sizeof(buts));
539 if (ret)
540 return -EFAULT;
541
542 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
543 if (ret)
544 return ret;
545
546 if (copy_to_user(arg, &buts, sizeof(buts))) {
547 blk_trace_remove(q);
548 return -EFAULT;
549 }
550 return 0;
551 }
552 EXPORT_SYMBOL_GPL(blk_trace_setup);
553
554 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
555 static int compat_blk_trace_setup(struct request_queue *q, char *name,
556 dev_t dev, struct block_device *bdev,
557 char __user *arg)
558 {
559 struct blk_user_trace_setup buts;
560 struct compat_blk_user_trace_setup cbuts;
561 int ret;
562
563 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
564 return -EFAULT;
565
566 buts = (struct blk_user_trace_setup) {
567 .act_mask = cbuts.act_mask,
568 .buf_size = cbuts.buf_size,
569 .buf_nr = cbuts.buf_nr,
570 .start_lba = cbuts.start_lba,
571 .end_lba = cbuts.end_lba,
572 .pid = cbuts.pid,
573 };
574 memcpy(&buts.name, &cbuts.name, 32);
575
576 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
577 if (ret)
578 return ret;
579
580 if (copy_to_user(arg, &buts.name, 32)) {
581 blk_trace_remove(q);
582 return -EFAULT;
583 }
584
585 return 0;
586 }
587 #endif
588
589 int blk_trace_startstop(struct request_queue *q, int start)
590 {
591 int ret;
592 struct blk_trace *bt = q->blk_trace;
593
594 if (bt == NULL)
595 return -EINVAL;
596
597 /*
598 * For starting a trace, we can transition from a setup or stopped
599 * trace. For stopping a trace, the state must be running
600 */
601 ret = -EINVAL;
602 if (start) {
603 if (bt->trace_state == Blktrace_setup ||
604 bt->trace_state == Blktrace_stopped) {
605 blktrace_seq++;
606 smp_mb();
607 bt->trace_state = Blktrace_running;
608
609 trace_note_time(bt);
610 ret = 0;
611 }
612 } else {
613 if (bt->trace_state == Blktrace_running) {
614 bt->trace_state = Blktrace_stopped;
615 relay_flush(bt->rchan);
616 ret = 0;
617 }
618 }
619
620 return ret;
621 }
622 EXPORT_SYMBOL_GPL(blk_trace_startstop);
623
624 /**
625 * blk_trace_ioctl: - handle the ioctls associated with tracing
626 * @bdev: the block device
627 * @cmd: the ioctl cmd
628 * @arg: the argument data, if any
629 *
630 **/
631 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
632 {
633 struct request_queue *q;
634 int ret, start = 0;
635 char b[BDEVNAME_SIZE];
636
637 q = bdev_get_queue(bdev);
638 if (!q)
639 return -ENXIO;
640
641 mutex_lock(&bdev->bd_mutex);
642
643 switch (cmd) {
644 case BLKTRACESETUP:
645 bdevname(bdev, b);
646 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
647 break;
648 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
649 case BLKTRACESETUP32:
650 bdevname(bdev, b);
651 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
652 break;
653 #endif
654 case BLKTRACESTART:
655 start = 1;
656 case BLKTRACESTOP:
657 ret = blk_trace_startstop(q, start);
658 break;
659 case BLKTRACETEARDOWN:
660 ret = blk_trace_remove(q);
661 break;
662 default:
663 ret = -ENOTTY;
664 break;
665 }
666
667 mutex_unlock(&bdev->bd_mutex);
668 return ret;
669 }
670
671 /**
672 * blk_trace_shutdown: - stop and cleanup trace structures
673 * @q: the request queue associated with the device
674 *
675 **/
676 void blk_trace_shutdown(struct request_queue *q)
677 {
678 if (q->blk_trace) {
679 blk_trace_startstop(q, 0);
680 blk_trace_remove(q);
681 }
682 }
683
684 /*
685 * blktrace probes
686 */
687
688 /**
689 * blk_add_trace_rq - Add a trace for a request oriented action
690 * @q: queue the io is for
691 * @rq: the source request
692 * @what: the action
693 *
694 * Description:
695 * Records an action against a request. Will log the bio offset + size.
696 *
697 **/
698 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
699 u32 what)
700 {
701 struct blk_trace *bt = q->blk_trace;
702 int rw = rq->cmd_flags & 0x03;
703
704 if (likely(!bt))
705 return;
706
707 if (rq->cmd_flags & REQ_DISCARD)
708 rw |= REQ_DISCARD;
709
710 if (rq->cmd_flags & REQ_SECURE)
711 rw |= REQ_SECURE;
712
713 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
714 what |= BLK_TC_ACT(BLK_TC_PC);
715 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
716 what, rq->errors, rq->cmd_len, rq->cmd);
717 } else {
718 what |= BLK_TC_ACT(BLK_TC_FS);
719 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
720 what, rq->errors, 0, NULL);
721 }
722 }
723
724 static void blk_add_trace_rq_abort(void *ignore,
725 struct request_queue *q, struct request *rq)
726 {
727 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
728 }
729
730 static void blk_add_trace_rq_insert(void *ignore,
731 struct request_queue *q, struct request *rq)
732 {
733 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
734 }
735
736 static void blk_add_trace_rq_issue(void *ignore,
737 struct request_queue *q, struct request *rq)
738 {
739 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
740 }
741
742 static void blk_add_trace_rq_requeue(void *ignore,
743 struct request_queue *q,
744 struct request *rq)
745 {
746 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
747 }
748
749 static void blk_add_trace_rq_complete(void *ignore,
750 struct request_queue *q,
751 struct request *rq)
752 {
753 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
754 }
755
756 /**
757 * blk_add_trace_bio - Add a trace for a bio oriented action
758 * @q: queue the io is for
759 * @bio: the source bio
760 * @what: the action
761 *
762 * Description:
763 * Records an action against a bio. Will log the bio offset + size.
764 *
765 **/
766 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
767 u32 what)
768 {
769 struct blk_trace *bt = q->blk_trace;
770
771 if (likely(!bt))
772 return;
773
774 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
775 !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
776 }
777
778 static void blk_add_trace_bio_bounce(void *ignore,
779 struct request_queue *q, struct bio *bio)
780 {
781 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
782 }
783
784 static void blk_add_trace_bio_complete(void *ignore,
785 struct request_queue *q, struct bio *bio)
786 {
787 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
788 }
789
790 static void blk_add_trace_bio_backmerge(void *ignore,
791 struct request_queue *q,
792 struct bio *bio)
793 {
794 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
795 }
796
797 static void blk_add_trace_bio_frontmerge(void *ignore,
798 struct request_queue *q,
799 struct bio *bio)
800 {
801 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
802 }
803
804 static void blk_add_trace_bio_queue(void *ignore,
805 struct request_queue *q, struct bio *bio)
806 {
807 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
808 }
809
810 static void blk_add_trace_getrq(void *ignore,
811 struct request_queue *q,
812 struct bio *bio, int rw)
813 {
814 if (bio)
815 blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
816 else {
817 struct blk_trace *bt = q->blk_trace;
818
819 if (bt)
820 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
821 }
822 }
823
824
825 static void blk_add_trace_sleeprq(void *ignore,
826 struct request_queue *q,
827 struct bio *bio, int rw)
828 {
829 if (bio)
830 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
831 else {
832 struct blk_trace *bt = q->blk_trace;
833
834 if (bt)
835 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
836 0, 0, NULL);
837 }
838 }
839
840 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
841 {
842 struct blk_trace *bt = q->blk_trace;
843
844 if (bt)
845 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
846 }
847
848 static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q)
849 {
850 struct blk_trace *bt = q->blk_trace;
851
852 if (bt) {
853 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
854 __be64 rpdu = cpu_to_be64(pdu);
855
856 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
857 sizeof(rpdu), &rpdu);
858 }
859 }
860
861 static void blk_add_trace_unplug_timer(void *ignore, struct request_queue *q)
862 {
863 struct blk_trace *bt = q->blk_trace;
864
865 if (bt) {
866 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
867 __be64 rpdu = cpu_to_be64(pdu);
868
869 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
870 sizeof(rpdu), &rpdu);
871 }
872 }
873
874 static void blk_add_trace_split(void *ignore,
875 struct request_queue *q, struct bio *bio,
876 unsigned int pdu)
877 {
878 struct blk_trace *bt = q->blk_trace;
879
880 if (bt) {
881 __be64 rpdu = cpu_to_be64(pdu);
882
883 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
884 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
885 sizeof(rpdu), &rpdu);
886 }
887 }
888
889 /**
890 * blk_add_trace_remap - Add a trace for a remap operation
891 * @ignore: trace callback data parameter (not used)
892 * @q: queue the io is for
893 * @bio: the source bio
894 * @dev: target device
895 * @from: source sector
896 *
897 * Description:
898 * Device mapper or raid target sometimes need to split a bio because
899 * it spans a stripe (or similar). Add a trace for that action.
900 *
901 **/
902 static void blk_add_trace_remap(void *ignore,
903 struct request_queue *q, struct bio *bio,
904 dev_t dev, sector_t from)
905 {
906 struct blk_trace *bt = q->blk_trace;
907 struct blk_io_trace_remap r;
908
909 if (likely(!bt))
910 return;
911
912 r.device_from = cpu_to_be32(dev);
913 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
914 r.sector_from = cpu_to_be64(from);
915
916 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
917 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
918 sizeof(r), &r);
919 }
920
921 /**
922 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
923 * @ignore: trace callback data parameter (not used)
924 * @q: queue the io is for
925 * @rq: the source request
926 * @dev: target device
927 * @from: source sector
928 *
929 * Description:
930 * Device mapper remaps request to other devices.
931 * Add a trace for that action.
932 *
933 **/
934 static void blk_add_trace_rq_remap(void *ignore,
935 struct request_queue *q,
936 struct request *rq, dev_t dev,
937 sector_t from)
938 {
939 struct blk_trace *bt = q->blk_trace;
940 struct blk_io_trace_remap r;
941
942 if (likely(!bt))
943 return;
944
945 r.device_from = cpu_to_be32(dev);
946 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
947 r.sector_from = cpu_to_be64(from);
948
949 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
950 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
951 sizeof(r), &r);
952 }
953
954 /**
955 * blk_add_driver_data - Add binary message with driver-specific data
956 * @q: queue the io is for
957 * @rq: io request
958 * @data: driver-specific data
959 * @len: length of driver-specific data
960 *
961 * Description:
962 * Some drivers might want to write driver-specific data per request.
963 *
964 **/
965 void blk_add_driver_data(struct request_queue *q,
966 struct request *rq,
967 void *data, size_t len)
968 {
969 struct blk_trace *bt = q->blk_trace;
970
971 if (likely(!bt))
972 return;
973
974 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
975 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
976 BLK_TA_DRV_DATA, rq->errors, len, data);
977 else
978 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
979 BLK_TA_DRV_DATA, rq->errors, len, data);
980 }
981 EXPORT_SYMBOL_GPL(blk_add_driver_data);
982
983 static void blk_register_tracepoints(void)
984 {
985 int ret;
986
987 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
988 WARN_ON(ret);
989 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
990 WARN_ON(ret);
991 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
992 WARN_ON(ret);
993 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
994 WARN_ON(ret);
995 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1006 WARN_ON(ret);
1007 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1008 WARN_ON(ret);
1009 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1010 WARN_ON(ret);
1011 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1012 WARN_ON(ret);
1013 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
1014 WARN_ON(ret);
1015 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
1016 WARN_ON(ret);
1017 ret = register_trace_block_split(blk_add_trace_split, NULL);
1018 WARN_ON(ret);
1019 ret = register_trace_block_remap(blk_add_trace_remap, NULL);
1020 WARN_ON(ret);
1021 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1022 WARN_ON(ret);
1023 }
1024
1025 static void blk_unregister_tracepoints(void)
1026 {
1027 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1028 unregister_trace_block_remap(blk_add_trace_remap, NULL);
1029 unregister_trace_block_split(blk_add_trace_split, NULL);
1030 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
1031 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
1032 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1033 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1034 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1035 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1036 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1037 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1038 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1039 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1040 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1041 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1042 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1043 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1044 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1045
1046 tracepoint_synchronize_unregister();
1047 }
1048
1049 /*
1050 * struct blk_io_tracer formatting routines
1051 */
1052
1053 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1054 {
1055 int i = 0;
1056 int tc = t->action >> BLK_TC_SHIFT;
1057
1058 if (t->action == BLK_TN_MESSAGE) {
1059 rwbs[i++] = 'N';
1060 goto out;
1061 }
1062
1063 if (tc & BLK_TC_DISCARD)
1064 rwbs[i++] = 'D';
1065 else if (tc & BLK_TC_WRITE)
1066 rwbs[i++] = 'W';
1067 else if (t->bytes)
1068 rwbs[i++] = 'R';
1069 else
1070 rwbs[i++] = 'N';
1071
1072 if (tc & BLK_TC_AHEAD)
1073 rwbs[i++] = 'A';
1074 if (tc & BLK_TC_BARRIER)
1075 rwbs[i++] = 'B';
1076 if (tc & BLK_TC_SYNC)
1077 rwbs[i++] = 'S';
1078 if (tc & BLK_TC_META)
1079 rwbs[i++] = 'M';
1080 out:
1081 rwbs[i] = '\0';
1082 }
1083
1084 static inline
1085 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1086 {
1087 return (const struct blk_io_trace *)ent;
1088 }
1089
1090 static inline const void *pdu_start(const struct trace_entry *ent)
1091 {
1092 return te_blk_io_trace(ent) + 1;
1093 }
1094
1095 static inline u32 t_action(const struct trace_entry *ent)
1096 {
1097 return te_blk_io_trace(ent)->action;
1098 }
1099
1100 static inline u32 t_bytes(const struct trace_entry *ent)
1101 {
1102 return te_blk_io_trace(ent)->bytes;
1103 }
1104
1105 static inline u32 t_sec(const struct trace_entry *ent)
1106 {
1107 return te_blk_io_trace(ent)->bytes >> 9;
1108 }
1109
1110 static inline unsigned long long t_sector(const struct trace_entry *ent)
1111 {
1112 return te_blk_io_trace(ent)->sector;
1113 }
1114
1115 static inline __u16 t_error(const struct trace_entry *ent)
1116 {
1117 return te_blk_io_trace(ent)->error;
1118 }
1119
1120 static __u64 get_pdu_int(const struct trace_entry *ent)
1121 {
1122 const __u64 *val = pdu_start(ent);
1123 return be64_to_cpu(*val);
1124 }
1125
1126 static void get_pdu_remap(const struct trace_entry *ent,
1127 struct blk_io_trace_remap *r)
1128 {
1129 const struct blk_io_trace_remap *__r = pdu_start(ent);
1130 __u64 sector_from = __r->sector_from;
1131
1132 r->device_from = be32_to_cpu(__r->device_from);
1133 r->device_to = be32_to_cpu(__r->device_to);
1134 r->sector_from = be64_to_cpu(sector_from);
1135 }
1136
1137 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1138
1139 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1140 {
1141 char rwbs[6];
1142 unsigned long long ts = iter->ts;
1143 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1144 unsigned secs = (unsigned long)ts;
1145 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1146
1147 fill_rwbs(rwbs, t);
1148
1149 return trace_seq_printf(&iter->seq,
1150 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1151 MAJOR(t->device), MINOR(t->device), iter->cpu,
1152 secs, nsec_rem, iter->ent->pid, act, rwbs);
1153 }
1154
1155 static int blk_log_action(struct trace_iterator *iter, const char *act)
1156 {
1157 char rwbs[6];
1158 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1159
1160 fill_rwbs(rwbs, t);
1161 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1162 MAJOR(t->device), MINOR(t->device), act, rwbs);
1163 }
1164
1165 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1166 {
1167 const unsigned char *pdu_buf;
1168 int pdu_len;
1169 int i, end, ret;
1170
1171 pdu_buf = pdu_start(ent);
1172 pdu_len = te_blk_io_trace(ent)->pdu_len;
1173
1174 if (!pdu_len)
1175 return 1;
1176
1177 /* find the last zero that needs to be printed */
1178 for (end = pdu_len - 1; end >= 0; end--)
1179 if (pdu_buf[end])
1180 break;
1181 end++;
1182
1183 if (!trace_seq_putc(s, '('))
1184 return 0;
1185
1186 for (i = 0; i < pdu_len; i++) {
1187
1188 ret = trace_seq_printf(s, "%s%02x",
1189 i == 0 ? "" : " ", pdu_buf[i]);
1190 if (!ret)
1191 return ret;
1192
1193 /*
1194 * stop when the rest is just zeroes and indicate so
1195 * with a ".." appended
1196 */
1197 if (i == end && end != pdu_len - 1)
1198 return trace_seq_puts(s, " ..) ");
1199 }
1200
1201 return trace_seq_puts(s, ") ");
1202 }
1203
1204 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1205 {
1206 char cmd[TASK_COMM_LEN];
1207
1208 trace_find_cmdline(ent->pid, cmd);
1209
1210 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1211 int ret;
1212
1213 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1214 if (!ret)
1215 return 0;
1216 ret = blk_log_dump_pdu(s, ent);
1217 if (!ret)
1218 return 0;
1219 return trace_seq_printf(s, "[%s]\n", cmd);
1220 } else {
1221 if (t_sec(ent))
1222 return trace_seq_printf(s, "%llu + %u [%s]\n",
1223 t_sector(ent), t_sec(ent), cmd);
1224 return trace_seq_printf(s, "[%s]\n", cmd);
1225 }
1226 }
1227
1228 static int blk_log_with_error(struct trace_seq *s,
1229 const struct trace_entry *ent)
1230 {
1231 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1232 int ret;
1233
1234 ret = blk_log_dump_pdu(s, ent);
1235 if (ret)
1236 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1237 return 0;
1238 } else {
1239 if (t_sec(ent))
1240 return trace_seq_printf(s, "%llu + %u [%d]\n",
1241 t_sector(ent),
1242 t_sec(ent), t_error(ent));
1243 return trace_seq_printf(s, "%llu [%d]\n",
1244 t_sector(ent), t_error(ent));
1245 }
1246 }
1247
1248 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1249 {
1250 struct blk_io_trace_remap r = { .device_from = 0, };
1251
1252 get_pdu_remap(ent, &r);
1253 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1254 t_sector(ent), t_sec(ent),
1255 MAJOR(r.device_from), MINOR(r.device_from),
1256 (unsigned long long)r.sector_from);
1257 }
1258
1259 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1260 {
1261 char cmd[TASK_COMM_LEN];
1262
1263 trace_find_cmdline(ent->pid, cmd);
1264
1265 return trace_seq_printf(s, "[%s]\n", cmd);
1266 }
1267
1268 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1269 {
1270 char cmd[TASK_COMM_LEN];
1271
1272 trace_find_cmdline(ent->pid, cmd);
1273
1274 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1275 }
1276
1277 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1278 {
1279 char cmd[TASK_COMM_LEN];
1280
1281 trace_find_cmdline(ent->pid, cmd);
1282
1283 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1284 get_pdu_int(ent), cmd);
1285 }
1286
1287 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1288 {
1289 int ret;
1290 const struct blk_io_trace *t = te_blk_io_trace(ent);
1291
1292 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1293 if (ret)
1294 return trace_seq_putc(s, '\n');
1295 return ret;
1296 }
1297
1298 /*
1299 * struct tracer operations
1300 */
1301
1302 static void blk_tracer_print_header(struct seq_file *m)
1303 {
1304 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1305 return;
1306 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1307 "# | | | | | |\n");
1308 }
1309
1310 static void blk_tracer_start(struct trace_array *tr)
1311 {
1312 blk_tracer_enabled = true;
1313 }
1314
1315 static int blk_tracer_init(struct trace_array *tr)
1316 {
1317 blk_tr = tr;
1318 blk_tracer_start(tr);
1319 return 0;
1320 }
1321
1322 static void blk_tracer_stop(struct trace_array *tr)
1323 {
1324 blk_tracer_enabled = false;
1325 }
1326
1327 static void blk_tracer_reset(struct trace_array *tr)
1328 {
1329 blk_tracer_stop(tr);
1330 }
1331
1332 static const struct {
1333 const char *act[2];
1334 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1335 } what2act[] = {
1336 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1337 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1338 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1339 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1340 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1341 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1342 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1343 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1344 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1345 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1346 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1347 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1348 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1349 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1350 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1351 };
1352
1353 static enum print_line_t print_one_line(struct trace_iterator *iter,
1354 bool classic)
1355 {
1356 struct trace_seq *s = &iter->seq;
1357 const struct blk_io_trace *t;
1358 u16 what;
1359 int ret;
1360 bool long_act;
1361 blk_log_action_t *log_action;
1362
1363 t = te_blk_io_trace(iter->ent);
1364 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1365 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1366 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1367
1368 if (t->action == BLK_TN_MESSAGE) {
1369 ret = log_action(iter, long_act ? "message" : "m");
1370 if (ret)
1371 ret = blk_log_msg(s, iter->ent);
1372 goto out;
1373 }
1374
1375 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1376 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1377 else {
1378 ret = log_action(iter, what2act[what].act[long_act]);
1379 if (ret)
1380 ret = what2act[what].print(s, iter->ent);
1381 }
1382 out:
1383 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1384 }
1385
1386 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1387 int flags, struct trace_event *event)
1388 {
1389 return print_one_line(iter, false);
1390 }
1391
1392 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1393 {
1394 struct trace_seq *s = &iter->seq;
1395 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1396 const int offset = offsetof(struct blk_io_trace, sector);
1397 struct blk_io_trace old = {
1398 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1399 .time = iter->ts,
1400 };
1401
1402 if (!trace_seq_putmem(s, &old, offset))
1403 return 0;
1404 return trace_seq_putmem(s, &t->sector,
1405 sizeof(old) - offset + t->pdu_len);
1406 }
1407
1408 static enum print_line_t
1409 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1410 struct trace_event *event)
1411 {
1412 return blk_trace_synthesize_old_trace(iter) ?
1413 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1414 }
1415
1416 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1417 {
1418 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1419 return TRACE_TYPE_UNHANDLED;
1420
1421 return print_one_line(iter, true);
1422 }
1423
1424 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1425 {
1426 /* don't output context-info for blk_classic output */
1427 if (bit == TRACE_BLK_OPT_CLASSIC) {
1428 if (set)
1429 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1430 else
1431 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1432 }
1433 return 0;
1434 }
1435
1436 static struct tracer blk_tracer __read_mostly = {
1437 .name = "blk",
1438 .init = blk_tracer_init,
1439 .reset = blk_tracer_reset,
1440 .start = blk_tracer_start,
1441 .stop = blk_tracer_stop,
1442 .print_header = blk_tracer_print_header,
1443 .print_line = blk_tracer_print_line,
1444 .flags = &blk_tracer_flags,
1445 .set_flag = blk_tracer_set_flag,
1446 };
1447
1448 static struct trace_event_functions trace_blk_event_funcs = {
1449 .trace = blk_trace_event_print,
1450 .binary = blk_trace_event_print_binary,
1451 };
1452
1453 static struct trace_event trace_blk_event = {
1454 .type = TRACE_BLK,
1455 .funcs = &trace_blk_event_funcs,
1456 };
1457
1458 static int __init init_blk_tracer(void)
1459 {
1460 if (!register_ftrace_event(&trace_blk_event)) {
1461 pr_warning("Warning: could not register block events\n");
1462 return 1;
1463 }
1464
1465 if (register_tracer(&blk_tracer) != 0) {
1466 pr_warning("Warning: could not register the block tracer\n");
1467 unregister_ftrace_event(&trace_blk_event);
1468 return 1;
1469 }
1470
1471 return 0;
1472 }
1473
1474 device_initcall(init_blk_tracer);
1475
1476 static int blk_trace_remove_queue(struct request_queue *q)
1477 {
1478 struct blk_trace *bt;
1479
1480 bt = xchg(&q->blk_trace, NULL);
1481 if (bt == NULL)
1482 return -EINVAL;
1483
1484 if (atomic_dec_and_test(&blk_probes_ref))
1485 blk_unregister_tracepoints();
1486
1487 blk_trace_free(bt);
1488 return 0;
1489 }
1490
1491 /*
1492 * Setup everything required to start tracing
1493 */
1494 static int blk_trace_setup_queue(struct request_queue *q,
1495 struct block_device *bdev)
1496 {
1497 struct blk_trace *old_bt, *bt = NULL;
1498 int ret = -ENOMEM;
1499
1500 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1501 if (!bt)
1502 return -ENOMEM;
1503
1504 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1505 if (!bt->msg_data)
1506 goto free_bt;
1507
1508 bt->dev = bdev->bd_dev;
1509 bt->act_mask = (u16)-1;
1510
1511 blk_trace_setup_lba(bt, bdev);
1512
1513 old_bt = xchg(&q->blk_trace, bt);
1514 if (old_bt != NULL) {
1515 (void)xchg(&q->blk_trace, old_bt);
1516 ret = -EBUSY;
1517 goto free_bt;
1518 }
1519
1520 if (atomic_inc_return(&blk_probes_ref) == 1)
1521 blk_register_tracepoints();
1522 return 0;
1523
1524 free_bt:
1525 blk_trace_free(bt);
1526 return ret;
1527 }
1528
1529 /*
1530 * sysfs interface to enable and configure tracing
1531 */
1532
1533 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1534 struct device_attribute *attr,
1535 char *buf);
1536 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1537 struct device_attribute *attr,
1538 const char *buf, size_t count);
1539 #define BLK_TRACE_DEVICE_ATTR(_name) \
1540 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1541 sysfs_blk_trace_attr_show, \
1542 sysfs_blk_trace_attr_store)
1543
1544 static BLK_TRACE_DEVICE_ATTR(enable);
1545 static BLK_TRACE_DEVICE_ATTR(act_mask);
1546 static BLK_TRACE_DEVICE_ATTR(pid);
1547 static BLK_TRACE_DEVICE_ATTR(start_lba);
1548 static BLK_TRACE_DEVICE_ATTR(end_lba);
1549
1550 static struct attribute *blk_trace_attrs[] = {
1551 &dev_attr_enable.attr,
1552 &dev_attr_act_mask.attr,
1553 &dev_attr_pid.attr,
1554 &dev_attr_start_lba.attr,
1555 &dev_attr_end_lba.attr,
1556 NULL
1557 };
1558
1559 struct attribute_group blk_trace_attr_group = {
1560 .name = "trace",
1561 .attrs = blk_trace_attrs,
1562 };
1563
1564 static const struct {
1565 int mask;
1566 const char *str;
1567 } mask_maps[] = {
1568 { BLK_TC_READ, "read" },
1569 { BLK_TC_WRITE, "write" },
1570 { BLK_TC_BARRIER, "barrier" },
1571 { BLK_TC_SYNC, "sync" },
1572 { BLK_TC_QUEUE, "queue" },
1573 { BLK_TC_REQUEUE, "requeue" },
1574 { BLK_TC_ISSUE, "issue" },
1575 { BLK_TC_COMPLETE, "complete" },
1576 { BLK_TC_FS, "fs" },
1577 { BLK_TC_PC, "pc" },
1578 { BLK_TC_AHEAD, "ahead" },
1579 { BLK_TC_META, "meta" },
1580 { BLK_TC_DISCARD, "discard" },
1581 { BLK_TC_DRV_DATA, "drv_data" },
1582 };
1583
1584 static 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
1619 static 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
1635 static 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
1643 static 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
1678 out_unlock_bdev:
1679 mutex_unlock(&bdev->bd_mutex);
1680 out_bdput:
1681 bdput(bdev);
1682 out:
1683 return ret;
1684 }
1685
1686 static 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
1746 out_unlock_bdev:
1747 mutex_unlock(&bdev->bd_mutex);
1748 out_bdput:
1749 bdput(bdev);
1750 out:
1751 return ret ? ret : count;
1752 }
1753
1754 int blk_trace_init_sysfs(struct device *dev)
1755 {
1756 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1757 }
1758
1759 void 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
1768 void 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
1793 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1794 {
1795 int i = 0;
1796
1797 if (rw & WRITE)
1798 rwbs[i++] = 'W';
1799 else if (rw & REQ_DISCARD)
1800 rwbs[i++] = 'D';
1801 else if (bytes)
1802 rwbs[i++] = 'R';
1803 else
1804 rwbs[i++] = 'N';
1805
1806 if (rw & REQ_RAHEAD)
1807 rwbs[i++] = 'A';
1808 if (rw & REQ_SYNC)
1809 rwbs[i++] = 'S';
1810 if (rw & REQ_META)
1811 rwbs[i++] = 'M';
1812 if (rw & REQ_SECURE)
1813 rwbs[i++] = 'E';
1814
1815 rwbs[i] = '\0';
1816 }
1817
1818 void blk_fill_rwbs_rq(char *rwbs, struct request *rq)
1819 {
1820 int rw = rq->cmd_flags & 0x03;
1821 int bytes;
1822
1823 if (rq->cmd_flags & REQ_DISCARD)
1824 rw |= REQ_DISCARD;
1825
1826 if (rq->cmd_flags & REQ_SECURE)
1827 rw |= REQ_SECURE;
1828
1829 bytes = blk_rq_bytes(rq);
1830
1831 blk_fill_rwbs(rwbs, rw, bytes);
1832 }
1833
1834 #endif /* CONFIG_EVENT_TRACING */
1835
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