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close_port, kpacket_gen kmalloc oom, formard.c wake_sender/skb receive oom handling...
[cor_2_6_31.git] / kernel / trace / blktrace.c
blob1090b0aed9bac6135d359e0cb07317085e6145d6
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/debugfs.h>
25 #include <linux/smp_lock.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 int pc = 0;
69 int cpu = smp_processor_id();
70 bool blk_tracer = blk_tracer_enabled;
71
72 if (blk_tracer) {
73 pc = preempt_count();
74 event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
75 sizeof(*t) + len,
76 0, pc);
77 if (!event)
78 return;
79 t = ring_buffer_event_data(event);
80 goto record_it;
81 }
82
83 if (!bt->rchan)
84 return;
85
86 t = relay_reserve(bt->rchan, sizeof(*t) + len);
87 if (t) {
88 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
89 t->time = ktime_to_ns(ktime_get());
90 record_it:
91 t->device = bt->dev;
92 t->action = action;
93 t->pid = pid;
94 t->cpu = cpu;
95 t->pdu_len = len;
96 memcpy((void *) t + sizeof(*t), data, len);
97
98 if (blk_tracer)
99 trace_buffer_unlock_commit(blk_tr, event, 0, pc);
100 }
101 }
102
103 /*
104 * Send out a notify for this process, if we haven't done so since a trace
105 * started
106 */
107 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
108 {
109 tsk->btrace_seq = blktrace_seq;
110 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
111 }
112
113 static void trace_note_time(struct blk_trace *bt)
114 {
115 struct timespec now;
116 unsigned long flags;
117 u32 words[2];
118
119 getnstimeofday(&now);
120 words[0] = now.tv_sec;
121 words[1] = now.tv_nsec;
122
123 local_irq_save(flags);
124 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
125 local_irq_restore(flags);
126 }
127
128 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
129 {
130 int n;
131 va_list args;
132 unsigned long flags;
133 char *buf;
134
135 if (unlikely(bt->trace_state != Blktrace_running &&
136 !blk_tracer_enabled))
137 return;
138
139 local_irq_save(flags);
140 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
141 va_start(args, fmt);
142 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
143 va_end(args);
144
145 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
146 local_irq_restore(flags);
147 }
148 EXPORT_SYMBOL_GPL(__trace_note_message);
149
150 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
151 pid_t pid)
152 {
153 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
154 return 1;
155 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
156 return 1;
157 if (bt->pid && pid != bt->pid)
158 return 1;
159
160 return 0;
161 }
162
163 /*
164 * Data direction bit lookup
165 */
166 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
167 BLK_TC_ACT(BLK_TC_WRITE) };
168
169 /* The ilog2() calls fall out because they're constant */
170 #define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
171 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name))
172
173 /*
174 * The worker for the various blk_add_trace*() types. Fills out a
175 * blk_io_trace structure and places it in a per-cpu subbuffer.
176 */
177 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
178 int rw, u32 what, int error, int pdu_len, void *pdu_data)
179 {
180 struct task_struct *tsk = current;
181 struct ring_buffer_event *event = NULL;
182 struct blk_io_trace *t;
183 unsigned long flags = 0;
184 unsigned long *sequence;
185 pid_t pid;
186 int cpu, pc = 0;
187 bool blk_tracer = blk_tracer_enabled;
188
189 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
190 return;
191
192 what |= ddir_act[rw & WRITE];
193 what |= MASK_TC_BIT(rw, BARRIER);
194 what |= MASK_TC_BIT(rw, SYNCIO);
195 what |= MASK_TC_BIT(rw, AHEAD);
196 what |= MASK_TC_BIT(rw, META);
197 what |= MASK_TC_BIT(rw, DISCARD);
198
199 pid = tsk->pid;
200 if (act_log_check(bt, what, sector, pid))
201 return;
202 cpu = raw_smp_processor_id();
203
204 if (blk_tracer) {
205 tracing_record_cmdline(current);
206
207 pc = preempt_count();
208 event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
209 sizeof(*t) + pdu_len,
210 0, pc);
211 if (!event)
212 return;
213 t = ring_buffer_event_data(event);
214 goto record_it;
215 }
216
217 /*
218 * A word about the locking here - we disable interrupts to reserve
219 * some space in the relay per-cpu buffer, to prevent an irq
220 * from coming in and stepping on our toes.
221 */
222 local_irq_save(flags);
223
224 if (unlikely(tsk->btrace_seq != blktrace_seq))
225 trace_note_tsk(bt, tsk);
226
227 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
228 if (t) {
229 sequence = per_cpu_ptr(bt->sequence, cpu);
230
231 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
232 t->sequence = ++(*sequence);
233 t->time = ktime_to_ns(ktime_get());
234 record_it:
235 /*
236 * These two are not needed in ftrace as they are in the
237 * generic trace_entry, filled by tracing_generic_entry_update,
238 * but for the trace_event->bin() synthesizer benefit we do it
239 * here too.
240 */
241 t->cpu = cpu;
242 t->pid = pid;
243
244 t->sector = sector;
245 t->bytes = bytes;
246 t->action = what;
247 t->device = bt->dev;
248 t->error = error;
249 t->pdu_len = pdu_len;
250
251 if (pdu_len)
252 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
253
254 if (blk_tracer) {
255 trace_buffer_unlock_commit(blk_tr, event, 0, pc);
256 return;
257 }
258 }
259
260 local_irq_restore(flags);
261 }
262
263 static struct dentry *blk_tree_root;
264 static DEFINE_MUTEX(blk_tree_mutex);
265
266 static void blk_trace_free(struct blk_trace *bt)
267 {
268 debugfs_remove(bt->msg_file);
269 debugfs_remove(bt->dropped_file);
270 debugfs_remove(bt->dir);
271 relay_close(bt->rchan);
272 free_percpu(bt->sequence);
273 free_percpu(bt->msg_data);
274 kfree(bt);
275 }
276
277 static void blk_trace_cleanup(struct blk_trace *bt)
278 {
279 blk_trace_free(bt);
280 if (atomic_dec_and_test(&blk_probes_ref))
281 blk_unregister_tracepoints();
282 }
283
284 int blk_trace_remove(struct request_queue *q)
285 {
286 struct blk_trace *bt;
287
288 bt = xchg(&q->blk_trace, NULL);
289 if (!bt)
290 return -EINVAL;
291
292 if (bt->trace_state != Blktrace_running)
293 blk_trace_cleanup(bt);
294
295 return 0;
296 }
297 EXPORT_SYMBOL_GPL(blk_trace_remove);
298
299 static int blk_dropped_open(struct inode *inode, struct file *filp)
300 {
301 filp->private_data = inode->i_private;
302
303 return 0;
304 }
305
306 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
307 size_t count, loff_t *ppos)
308 {
309 struct blk_trace *bt = filp->private_data;
310 char buf[16];
311
312 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
313
314 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
315 }
316
317 static const struct file_operations blk_dropped_fops = {
318 .owner = THIS_MODULE,
319 .open = blk_dropped_open,
320 .read = blk_dropped_read,
321 };
322
323 static int blk_msg_open(struct inode *inode, struct file *filp)
324 {
325 filp->private_data = inode->i_private;
326
327 return 0;
328 }
329
330 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
331 size_t count, loff_t *ppos)
332 {
333 char *msg;
334 struct blk_trace *bt;
335
336 if (count >= BLK_TN_MAX_MSG)
337 return -EINVAL;
338
339 msg = kmalloc(count + 1, GFP_KERNEL);
340 if (msg == NULL)
341 return -ENOMEM;
342
343 if (copy_from_user(msg, buffer, count)) {
344 kfree(msg);
345 return -EFAULT;
346 }
347
348 msg[count] = '\0';
349 bt = filp->private_data;
350 __trace_note_message(bt, "%s", msg);
351 kfree(msg);
352
353 return count;
354 }
355
356 static const struct file_operations blk_msg_fops = {
357 .owner = THIS_MODULE,
358 .open = blk_msg_open,
359 .write = blk_msg_write,
360 };
361
362 /*
363 * Keep track of how many times we encountered a full subbuffer, to aid
364 * the user space app in telling how many lost events there were.
365 */
366 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
367 void *prev_subbuf, size_t prev_padding)
368 {
369 struct blk_trace *bt;
370
371 if (!relay_buf_full(buf))
372 return 1;
373
374 bt = buf->chan->private_data;
375 atomic_inc(&bt->dropped);
376 return 0;
377 }
378
379 static int blk_remove_buf_file_callback(struct dentry *dentry)
380 {
381 struct dentry *parent = dentry->d_parent;
382 debugfs_remove(dentry);
383
384 /*
385 * this will fail for all but the last file, but that is ok. what we
386 * care about is the top level buts->name directory going away, when
387 * the last trace file is gone. Then we don't have to rmdir() that
388 * manually on trace stop, so it nicely solves the issue with
389 * force killing of running traces.
390 */
391
392 debugfs_remove(parent);
393 return 0;
394 }
395
396 static struct dentry *blk_create_buf_file_callback(const char *filename,
397 struct dentry *parent,
398 int mode,
399 struct rchan_buf *buf,
400 int *is_global)
401 {
402 return debugfs_create_file(filename, mode, parent, buf,
403 &relay_file_operations);
404 }
405
406 static struct rchan_callbacks blk_relay_callbacks = {
407 .subbuf_start = blk_subbuf_start_callback,
408 .create_buf_file = blk_create_buf_file_callback,
409 .remove_buf_file = blk_remove_buf_file_callback,
410 };
411
412 static void blk_trace_setup_lba(struct blk_trace *bt,
413 struct block_device *bdev)
414 {
415 struct hd_struct *part = NULL;
416
417 if (bdev)
418 part = bdev->bd_part;
419
420 if (part) {
421 bt->start_lba = part->start_sect;
422 bt->end_lba = part->start_sect + part->nr_sects;
423 } else {
424 bt->start_lba = 0;
425 bt->end_lba = -1ULL;
426 }
427 }
428
429 /*
430 * Setup everything required to start tracing
431 */
432 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
433 struct block_device *bdev,
434 struct blk_user_trace_setup *buts)
435 {
436 struct blk_trace *old_bt, *bt = NULL;
437 struct dentry *dir = NULL;
438 int ret, i;
439
440 if (!buts->buf_size || !buts->buf_nr)
441 return -EINVAL;
442
443 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
444 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
445
446 /*
447 * some device names have larger paths - convert the slashes
448 * to underscores for this to work as expected
449 */
450 for (i = 0; i < strlen(buts->name); i++)
451 if (buts->name[i] == '/')
452 buts->name[i] = '_';
453
454 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
455 if (!bt)
456 return -ENOMEM;
457
458 ret = -ENOMEM;
459 bt->sequence = alloc_percpu(unsigned long);
460 if (!bt->sequence)
461 goto err;
462
463 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
464 if (!bt->msg_data)
465 goto err;
466
467 ret = -ENOENT;
468
469 mutex_lock(&blk_tree_mutex);
470 if (!blk_tree_root) {
471 blk_tree_root = debugfs_create_dir("block", NULL);
472 if (!blk_tree_root) {
473 mutex_unlock(&blk_tree_mutex);
474 goto err;
475 }
476 }
477 mutex_unlock(&blk_tree_mutex);
478
479 dir = debugfs_create_dir(buts->name, blk_tree_root);
480
481 if (!dir)
482 goto err;
483
484 bt->dir = dir;
485 bt->dev = dev;
486 atomic_set(&bt->dropped, 0);
487
488 ret = -EIO;
489 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
490 &blk_dropped_fops);
491 if (!bt->dropped_file)
492 goto err;
493
494 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
495 if (!bt->msg_file)
496 goto err;
497
498 bt->rchan = relay_open("trace", dir, buts->buf_size,
499 buts->buf_nr, &blk_relay_callbacks, bt);
500 if (!bt->rchan)
501 goto err;
502
503 bt->act_mask = buts->act_mask;
504 if (!bt->act_mask)
505 bt->act_mask = (u16) -1;
506
507 blk_trace_setup_lba(bt, bdev);
508
509 /* overwrite with user settings */
510 if (buts->start_lba)
511 bt->start_lba = buts->start_lba;
512 if (buts->end_lba)
513 bt->end_lba = buts->end_lba;
514
515 bt->pid = buts->pid;
516 bt->trace_state = Blktrace_setup;
517
518 ret = -EBUSY;
519 old_bt = xchg(&q->blk_trace, bt);
520 if (old_bt) {
521 (void) xchg(&q->blk_trace, old_bt);
522 goto err;
523 }
524
525 if (atomic_inc_return(&blk_probes_ref) == 1)
526 blk_register_tracepoints();
527
528 return 0;
529 err:
530 blk_trace_free(bt);
531 return ret;
532 }
533
534 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
535 struct block_device *bdev,
536 char __user *arg)
537 {
538 struct blk_user_trace_setup buts;
539 int ret;
540
541 ret = copy_from_user(&buts, arg, sizeof(buts));
542 if (ret)
543 return -EFAULT;
544
545 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
546 if (ret)
547 return ret;
548
549 if (copy_to_user(arg, &buts, sizeof(buts)))
550 return -EFAULT;
551
552 return 0;
553 }
554 EXPORT_SYMBOL_GPL(blk_trace_setup);
555
556 int blk_trace_startstop(struct request_queue *q, int start)
557 {
558 int ret;
559 struct blk_trace *bt = q->blk_trace;
560
561 if (bt == NULL)
562 return -EINVAL;
563
564 /*
565 * For starting a trace, we can transition from a setup or stopped
566 * trace. For stopping a trace, the state must be running
567 */
568 ret = -EINVAL;
569 if (start) {
570 if (bt->trace_state == Blktrace_setup ||
571 bt->trace_state == Blktrace_stopped) {
572 blktrace_seq++;
573 smp_mb();
574 bt->trace_state = Blktrace_running;
575
576 trace_note_time(bt);
577 ret = 0;
578 }
579 } else {
580 if (bt->trace_state == Blktrace_running) {
581 bt->trace_state = Blktrace_stopped;
582 relay_flush(bt->rchan);
583 ret = 0;
584 }
585 }
586
587 return ret;
588 }
589 EXPORT_SYMBOL_GPL(blk_trace_startstop);
590
591 /**
592 * blk_trace_ioctl: - handle the ioctls associated with tracing
593 * @bdev: the block device
594 * @cmd: the ioctl cmd
595 * @arg: the argument data, if any
596 *
597 **/
598 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
599 {
600 struct request_queue *q;
601 int ret, start = 0;
602 char b[BDEVNAME_SIZE];
603
604 q = bdev_get_queue(bdev);
605 if (!q)
606 return -ENXIO;
607
608 mutex_lock(&bdev->bd_mutex);
609
610 switch (cmd) {
611 case BLKTRACESETUP:
612 bdevname(bdev, b);
613 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
614 break;
615 case BLKTRACESTART:
616 start = 1;
617 case BLKTRACESTOP:
618 ret = blk_trace_startstop(q, start);
619 break;
620 case BLKTRACETEARDOWN:
621 ret = blk_trace_remove(q);
622 break;
623 default:
624 ret = -ENOTTY;
625 break;
626 }
627
628 mutex_unlock(&bdev->bd_mutex);
629 return ret;
630 }
631
632 /**
633 * blk_trace_shutdown: - stop and cleanup trace structures
634 * @q: the request queue associated with the device
635 *
636 **/
637 void blk_trace_shutdown(struct request_queue *q)
638 {
639 if (q->blk_trace) {
640 blk_trace_startstop(q, 0);
641 blk_trace_remove(q);
642 }
643 }
644
645 /*
646 * blktrace probes
647 */
648
649 /**
650 * blk_add_trace_rq - Add a trace for a request oriented action
651 * @q: queue the io is for
652 * @rq: the source request
653 * @what: the action
654 *
655 * Description:
656 * Records an action against a request. Will log the bio offset + size.
657 *
658 **/
659 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
660 u32 what)
661 {
662 struct blk_trace *bt = q->blk_trace;
663 int rw = rq->cmd_flags & 0x03;
664
665 if (likely(!bt))
666 return;
667
668 if (blk_discard_rq(rq))
669 rw |= (1 << BIO_RW_DISCARD);
670
671 if (blk_pc_request(rq)) {
672 what |= BLK_TC_ACT(BLK_TC_PC);
673 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
674 what, rq->errors, rq->cmd_len, rq->cmd);
675 } else {
676 what |= BLK_TC_ACT(BLK_TC_FS);
677 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
678 what, rq->errors, 0, NULL);
679 }
680 }
681
682 static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq)
683 {
684 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
685 }
686
687 static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq)
688 {
689 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
690 }
691
692 static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq)
693 {
694 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
695 }
696
697 static void blk_add_trace_rq_requeue(struct request_queue *q,
698 struct request *rq)
699 {
700 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
701 }
702
703 static void blk_add_trace_rq_complete(struct request_queue *q,
704 struct request *rq)
705 {
706 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
707 }
708
709 /**
710 * blk_add_trace_bio - Add a trace for a bio oriented action
711 * @q: queue the io is for
712 * @bio: the source bio
713 * @what: the action
714 *
715 * Description:
716 * Records an action against a bio. Will log the bio offset + size.
717 *
718 **/
719 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
720 u32 what)
721 {
722 struct blk_trace *bt = q->blk_trace;
723
724 if (likely(!bt))
725 return;
726
727 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
728 !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
729 }
730
731 static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio)
732 {
733 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
734 }
735
736 static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio)
737 {
738 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
739 }
740
741 static void blk_add_trace_bio_backmerge(struct request_queue *q,
742 struct bio *bio)
743 {
744 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
745 }
746
747 static void blk_add_trace_bio_frontmerge(struct request_queue *q,
748 struct bio *bio)
749 {
750 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
751 }
752
753 static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio)
754 {
755 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
756 }
757
758 static void blk_add_trace_getrq(struct request_queue *q,
759 struct bio *bio, int rw)
760 {
761 if (bio)
762 blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
763 else {
764 struct blk_trace *bt = q->blk_trace;
765
766 if (bt)
767 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
768 }
769 }
770
771
772 static void blk_add_trace_sleeprq(struct request_queue *q,
773 struct bio *bio, int rw)
774 {
775 if (bio)
776 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
777 else {
778 struct blk_trace *bt = q->blk_trace;
779
780 if (bt)
781 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
782 0, 0, NULL);
783 }
784 }
785
786 static void blk_add_trace_plug(struct request_queue *q)
787 {
788 struct blk_trace *bt = q->blk_trace;
789
790 if (bt)
791 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
792 }
793
794 static void blk_add_trace_unplug_io(struct request_queue *q)
795 {
796 struct blk_trace *bt = q->blk_trace;
797
798 if (bt) {
799 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
800 __be64 rpdu = cpu_to_be64(pdu);
801
802 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
803 sizeof(rpdu), &rpdu);
804 }
805 }
806
807 static void blk_add_trace_unplug_timer(struct request_queue *q)
808 {
809 struct blk_trace *bt = q->blk_trace;
810
811 if (bt) {
812 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
813 __be64 rpdu = cpu_to_be64(pdu);
814
815 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
816 sizeof(rpdu), &rpdu);
817 }
818 }
819
820 static void blk_add_trace_split(struct request_queue *q, struct bio *bio,
821 unsigned int pdu)
822 {
823 struct blk_trace *bt = q->blk_trace;
824
825 if (bt) {
826 __be64 rpdu = cpu_to_be64(pdu);
827
828 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
829 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
830 sizeof(rpdu), &rpdu);
831 }
832 }
833
834 /**
835 * blk_add_trace_remap - Add a trace for a remap operation
836 * @q: queue the io is for
837 * @bio: the source bio
838 * @dev: target device
839 * @from: source sector
840 *
841 * Description:
842 * Device mapper or raid target sometimes need to split a bio because
843 * it spans a stripe (or similar). Add a trace for that action.
844 *
845 **/
846 static void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
847 dev_t dev, sector_t from)
848 {
849 struct blk_trace *bt = q->blk_trace;
850 struct blk_io_trace_remap r;
851
852 if (likely(!bt))
853 return;
854
855 r.device_from = cpu_to_be32(dev);
856 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
857 r.sector_from = cpu_to_be64(from);
858
859 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
860 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
861 sizeof(r), &r);
862 }
863
864 /**
865 * blk_add_driver_data - Add binary message with driver-specific data
866 * @q: queue the io is for
867 * @rq: io request
868 * @data: driver-specific data
869 * @len: length of driver-specific data
870 *
871 * Description:
872 * Some drivers might want to write driver-specific data per request.
873 *
874 **/
875 void blk_add_driver_data(struct request_queue *q,
876 struct request *rq,
877 void *data, size_t len)
878 {
879 struct blk_trace *bt = q->blk_trace;
880
881 if (likely(!bt))
882 return;
883
884 if (blk_pc_request(rq))
885 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
886 BLK_TA_DRV_DATA, rq->errors, len, data);
887 else
888 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
889 BLK_TA_DRV_DATA, rq->errors, len, data);
890 }
891 EXPORT_SYMBOL_GPL(blk_add_driver_data);
892
893 static void blk_register_tracepoints(void)
894 {
895 int ret;
896
897 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort);
898 WARN_ON(ret);
899 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert);
900 WARN_ON(ret);
901 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue);
902 WARN_ON(ret);
903 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue);
904 WARN_ON(ret);
905 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete);
906 WARN_ON(ret);
907 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce);
908 WARN_ON(ret);
909 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete);
910 WARN_ON(ret);
911 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
912 WARN_ON(ret);
913 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
914 WARN_ON(ret);
915 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue);
916 WARN_ON(ret);
917 ret = register_trace_block_getrq(blk_add_trace_getrq);
918 WARN_ON(ret);
919 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq);
920 WARN_ON(ret);
921 ret = register_trace_block_plug(blk_add_trace_plug);
922 WARN_ON(ret);
923 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer);
924 WARN_ON(ret);
925 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io);
926 WARN_ON(ret);
927 ret = register_trace_block_split(blk_add_trace_split);
928 WARN_ON(ret);
929 ret = register_trace_block_remap(blk_add_trace_remap);
930 WARN_ON(ret);
931 }
932
933 static void blk_unregister_tracepoints(void)
934 {
935 unregister_trace_block_remap(blk_add_trace_remap);
936 unregister_trace_block_split(blk_add_trace_split);
937 unregister_trace_block_unplug_io(blk_add_trace_unplug_io);
938 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer);
939 unregister_trace_block_plug(blk_add_trace_plug);
940 unregister_trace_block_sleeprq(blk_add_trace_sleeprq);
941 unregister_trace_block_getrq(blk_add_trace_getrq);
942 unregister_trace_block_bio_queue(blk_add_trace_bio_queue);
943 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
944 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
945 unregister_trace_block_bio_complete(blk_add_trace_bio_complete);
946 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce);
947 unregister_trace_block_rq_complete(blk_add_trace_rq_complete);
948 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue);
949 unregister_trace_block_rq_issue(blk_add_trace_rq_issue);
950 unregister_trace_block_rq_insert(blk_add_trace_rq_insert);
951 unregister_trace_block_rq_abort(blk_add_trace_rq_abort);
952
953 tracepoint_synchronize_unregister();
954 }
955
956 /*
957 * struct blk_io_tracer formatting routines
958 */
959
960 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
961 {
962 int i = 0;
963 int tc = t->action >> BLK_TC_SHIFT;
964
965 if (t->action == BLK_TN_MESSAGE) {
966 rwbs[i++] = 'N';
967 goto out;
968 }
969
970 if (tc & BLK_TC_DISCARD)
971 rwbs[i++] = 'D';
972 else if (tc & BLK_TC_WRITE)
973 rwbs[i++] = 'W';
974 else if (t->bytes)
975 rwbs[i++] = 'R';
976 else
977 rwbs[i++] = 'N';
978
979 if (tc & BLK_TC_AHEAD)
980 rwbs[i++] = 'A';
981 if (tc & BLK_TC_BARRIER)
982 rwbs[i++] = 'B';
983 if (tc & BLK_TC_SYNC)
984 rwbs[i++] = 'S';
985 if (tc & BLK_TC_META)
986 rwbs[i++] = 'M';
987 out:
988 rwbs[i] = '\0';
989 }
990
991 static inline
992 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
993 {
994 return (const struct blk_io_trace *)ent;
995 }
996
997 static inline const void *pdu_start(const struct trace_entry *ent)
998 {
999 return te_blk_io_trace(ent) + 1;
1000 }
1001
1002 static inline u32 t_action(const struct trace_entry *ent)
1003 {
1004 return te_blk_io_trace(ent)->action;
1005 }
1006
1007 static inline u32 t_bytes(const struct trace_entry *ent)
1008 {
1009 return te_blk_io_trace(ent)->bytes;
1010 }
1011
1012 static inline u32 t_sec(const struct trace_entry *ent)
1013 {
1014 return te_blk_io_trace(ent)->bytes >> 9;
1015 }
1016
1017 static inline unsigned long long t_sector(const struct trace_entry *ent)
1018 {
1019 return te_blk_io_trace(ent)->sector;
1020 }
1021
1022 static inline __u16 t_error(const struct trace_entry *ent)
1023 {
1024 return te_blk_io_trace(ent)->error;
1025 }
1026
1027 static __u64 get_pdu_int(const struct trace_entry *ent)
1028 {
1029 const __u64 *val = pdu_start(ent);
1030 return be64_to_cpu(*val);
1031 }
1032
1033 static void get_pdu_remap(const struct trace_entry *ent,
1034 struct blk_io_trace_remap *r)
1035 {
1036 const struct blk_io_trace_remap *__r = pdu_start(ent);
1037 __u64 sector_from = __r->sector_from;
1038
1039 r->device_from = be32_to_cpu(__r->device_from);
1040 r->device_to = be32_to_cpu(__r->device_to);
1041 r->sector_from = be64_to_cpu(sector_from);
1042 }
1043
1044 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1045
1046 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1047 {
1048 char rwbs[6];
1049 unsigned long long ts = iter->ts;
1050 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1051 unsigned secs = (unsigned long)ts;
1052 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1053
1054 fill_rwbs(rwbs, t);
1055
1056 return trace_seq_printf(&iter->seq,
1057 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1058 MAJOR(t->device), MINOR(t->device), iter->cpu,
1059 secs, nsec_rem, iter->ent->pid, act, rwbs);
1060 }
1061
1062 static int blk_log_action(struct trace_iterator *iter, const char *act)
1063 {
1064 char rwbs[6];
1065 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1066
1067 fill_rwbs(rwbs, t);
1068 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1069 MAJOR(t->device), MINOR(t->device), act, rwbs);
1070 }
1071
1072 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1073 {
1074 const unsigned char *pdu_buf;
1075 int pdu_len;
1076 int i, end, ret;
1077
1078 pdu_buf = pdu_start(ent);
1079 pdu_len = te_blk_io_trace(ent)->pdu_len;
1080
1081 if (!pdu_len)
1082 return 1;
1083
1084 /* find the last zero that needs to be printed */
1085 for (end = pdu_len - 1; end >= 0; end--)
1086 if (pdu_buf[end])
1087 break;
1088 end++;
1089
1090 if (!trace_seq_putc(s, '('))
1091 return 0;
1092
1093 for (i = 0; i < pdu_len; i++) {
1094
1095 ret = trace_seq_printf(s, "%s%02x",
1096 i == 0 ? "" : " ", pdu_buf[i]);
1097 if (!ret)
1098 return ret;
1099
1100 /*
1101 * stop when the rest is just zeroes and indicate so
1102 * with a ".." appended
1103 */
1104 if (i == end && end != pdu_len - 1)
1105 return trace_seq_puts(s, " ..) ");
1106 }
1107
1108 return trace_seq_puts(s, ") ");
1109 }
1110
1111 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1112 {
1113 char cmd[TASK_COMM_LEN];
1114
1115 trace_find_cmdline(ent->pid, cmd);
1116
1117 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1118 int ret;
1119
1120 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1121 if (!ret)
1122 return 0;
1123 ret = blk_log_dump_pdu(s, ent);
1124 if (!ret)
1125 return 0;
1126 return trace_seq_printf(s, "[%s]\n", cmd);
1127 } else {
1128 if (t_sec(ent))
1129 return trace_seq_printf(s, "%llu + %u [%s]\n",
1130 t_sector(ent), t_sec(ent), cmd);
1131 return trace_seq_printf(s, "[%s]\n", cmd);
1132 }
1133 }
1134
1135 static int blk_log_with_error(struct trace_seq *s,
1136 const struct trace_entry *ent)
1137 {
1138 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1139 int ret;
1140
1141 ret = blk_log_dump_pdu(s, ent);
1142 if (ret)
1143 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1144 return 0;
1145 } else {
1146 if (t_sec(ent))
1147 return trace_seq_printf(s, "%llu + %u [%d]\n",
1148 t_sector(ent),
1149 t_sec(ent), t_error(ent));
1150 return trace_seq_printf(s, "%llu [%d]\n",
1151 t_sector(ent), t_error(ent));
1152 }
1153 }
1154
1155 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1156 {
1157 struct blk_io_trace_remap r = { .device_from = 0, };
1158
1159 get_pdu_remap(ent, &r);
1160 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1161 t_sector(ent), t_sec(ent),
1162 MAJOR(r.device_from), MINOR(r.device_from),
1163 (unsigned long long)r.sector_from);
1164 }
1165
1166 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1167 {
1168 char cmd[TASK_COMM_LEN];
1169
1170 trace_find_cmdline(ent->pid, cmd);
1171
1172 return trace_seq_printf(s, "[%s]\n", cmd);
1173 }
1174
1175 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1176 {
1177 char cmd[TASK_COMM_LEN];
1178
1179 trace_find_cmdline(ent->pid, cmd);
1180
1181 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1182 }
1183
1184 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1185 {
1186 char cmd[TASK_COMM_LEN];
1187
1188 trace_find_cmdline(ent->pid, cmd);
1189
1190 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1191 get_pdu_int(ent), cmd);
1192 }
1193
1194 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1195 {
1196 int ret;
1197 const struct blk_io_trace *t = te_blk_io_trace(ent);
1198
1199 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1200 if (ret)
1201 return trace_seq_putc(s, '\n');
1202 return ret;
1203 }
1204
1205 /*
1206 * struct tracer operations
1207 */
1208
1209 static void blk_tracer_print_header(struct seq_file *m)
1210 {
1211 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1212 return;
1213 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1214 "# | | | | | |\n");
1215 }
1216
1217 static void blk_tracer_start(struct trace_array *tr)
1218 {
1219 blk_tracer_enabled = true;
1220 }
1221
1222 static int blk_tracer_init(struct trace_array *tr)
1223 {
1224 blk_tr = tr;
1225 blk_tracer_start(tr);
1226 return 0;
1227 }
1228
1229 static void blk_tracer_stop(struct trace_array *tr)
1230 {
1231 blk_tracer_enabled = false;
1232 }
1233
1234 static void blk_tracer_reset(struct trace_array *tr)
1235 {
1236 blk_tracer_stop(tr);
1237 }
1238
1239 static const struct {
1240 const char *act[2];
1241 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1242 } what2act[] = {
1243 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1244 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1245 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1246 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1247 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1248 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1249 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1250 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1251 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1252 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1253 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1254 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1255 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1256 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1257 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1258 };
1259
1260 static enum print_line_t print_one_line(struct trace_iterator *iter,
1261 bool classic)
1262 {
1263 struct trace_seq *s = &iter->seq;
1264 const struct blk_io_trace *t;
1265 u16 what;
1266 int ret;
1267 bool long_act;
1268 blk_log_action_t *log_action;
1269
1270 t = te_blk_io_trace(iter->ent);
1271 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1272 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1273 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1274
1275 if (t->action == BLK_TN_MESSAGE) {
1276 ret = log_action(iter, long_act ? "message" : "m");
1277 if (ret)
1278 ret = blk_log_msg(s, iter->ent);
1279 goto out;
1280 }
1281
1282 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1283 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1284 else {
1285 ret = log_action(iter, what2act[what].act[long_act]);
1286 if (ret)
1287 ret = what2act[what].print(s, iter->ent);
1288 }
1289 out:
1290 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1291 }
1292
1293 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1294 int flags)
1295 {
1296 return print_one_line(iter, false);
1297 }
1298
1299 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1300 {
1301 struct trace_seq *s = &iter->seq;
1302 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1303 const int offset = offsetof(struct blk_io_trace, sector);
1304 struct blk_io_trace old = {
1305 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1306 .time = iter->ts,
1307 };
1308
1309 if (!trace_seq_putmem(s, &old, offset))
1310 return 0;
1311 return trace_seq_putmem(s, &t->sector,
1312 sizeof(old) - offset + t->pdu_len);
1313 }
1314
1315 static enum print_line_t
1316 blk_trace_event_print_binary(struct trace_iterator *iter, int flags)
1317 {
1318 return blk_trace_synthesize_old_trace(iter) ?
1319 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1320 }
1321
1322 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1323 {
1324 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1325 return TRACE_TYPE_UNHANDLED;
1326
1327 return print_one_line(iter, true);
1328 }
1329
1330 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1331 {
1332 /* don't output context-info for blk_classic output */
1333 if (bit == TRACE_BLK_OPT_CLASSIC) {
1334 if (set)
1335 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1336 else
1337 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1338 }
1339 return 0;
1340 }
1341
1342 static struct tracer blk_tracer __read_mostly = {
1343 .name = "blk",
1344 .init = blk_tracer_init,
1345 .reset = blk_tracer_reset,
1346 .start = blk_tracer_start,
1347 .stop = blk_tracer_stop,
1348 .print_header = blk_tracer_print_header,
1349 .print_line = blk_tracer_print_line,
1350 .flags = &blk_tracer_flags,
1351 .set_flag = blk_tracer_set_flag,
1352 };
1353
1354 static struct trace_event trace_blk_event = {
1355 .type = TRACE_BLK,
1356 .trace = blk_trace_event_print,
1357 .binary = blk_trace_event_print_binary,
1358 };
1359
1360 static int __init init_blk_tracer(void)
1361 {
1362 if (!register_ftrace_event(&trace_blk_event)) {
1363 pr_warning("Warning: could not register block events\n");
1364 return 1;
1365 }
1366
1367 if (register_tracer(&blk_tracer) != 0) {
1368 pr_warning("Warning: could not register the block tracer\n");
1369 unregister_ftrace_event(&trace_blk_event);
1370 return 1;
1371 }
1372
1373 return 0;
1374 }
1375
1376 device_initcall(init_blk_tracer);
1377
1378 static int blk_trace_remove_queue(struct request_queue *q)
1379 {
1380 struct blk_trace *bt;
1381
1382 bt = xchg(&q->blk_trace, NULL);
1383 if (bt == NULL)
1384 return -EINVAL;
1385
1386 if (atomic_dec_and_test(&blk_probes_ref))
1387 blk_unregister_tracepoints();
1388
1389 blk_trace_free(bt);
1390 return 0;
1391 }
1392
1393 /*
1394 * Setup everything required to start tracing
1395 */
1396 static int blk_trace_setup_queue(struct request_queue *q,
1397 struct block_device *bdev)
1398 {
1399 struct blk_trace *old_bt, *bt = NULL;
1400 int ret = -ENOMEM;
1401
1402 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1403 if (!bt)
1404 return -ENOMEM;
1405
1406 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1407 if (!bt->msg_data)
1408 goto free_bt;
1409
1410 bt->dev = bdev->bd_dev;
1411 bt->act_mask = (u16)-1;
1412
1413 blk_trace_setup_lba(bt, bdev);
1414
1415 old_bt = xchg(&q->blk_trace, bt);
1416 if (old_bt != NULL) {
1417 (void)xchg(&q->blk_trace, old_bt);
1418 ret = -EBUSY;
1419 goto free_bt;
1420 }
1421
1422 if (atomic_inc_return(&blk_probes_ref) == 1)
1423 blk_register_tracepoints();
1424 return 0;
1425
1426 free_bt:
1427 blk_trace_free(bt);
1428 return ret;
1429 }
1430
1431 /*
1432 * sysfs interface to enable and configure tracing
1433 */
1434
1435 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1436 struct device_attribute *attr,
1437 char *buf);
1438 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1439 struct device_attribute *attr,
1440 const char *buf, size_t count);
1441 #define BLK_TRACE_DEVICE_ATTR(_name) \
1442 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1443 sysfs_blk_trace_attr_show, \
1444 sysfs_blk_trace_attr_store)
1445
1446 static BLK_TRACE_DEVICE_ATTR(enable);
1447 static BLK_TRACE_DEVICE_ATTR(act_mask);
1448 static BLK_TRACE_DEVICE_ATTR(pid);
1449 static BLK_TRACE_DEVICE_ATTR(start_lba);
1450 static BLK_TRACE_DEVICE_ATTR(end_lba);
1451
1452 static struct attribute *blk_trace_attrs[] = {
1453 &dev_attr_enable.attr,
1454 &dev_attr_act_mask.attr,
1455 &dev_attr_pid.attr,
1456 &dev_attr_start_lba.attr,
1457 &dev_attr_end_lba.attr,
1458 NULL
1459 };
1460
1461 struct attribute_group blk_trace_attr_group = {
1462 .name = "trace",
1463 .attrs = blk_trace_attrs,
1464 };
1465
1466 static const struct {
1467 int mask;
1468 const char *str;
1469 } mask_maps[] = {
1470 { BLK_TC_READ, "read" },
1471 { BLK_TC_WRITE, "write" },
1472 { BLK_TC_BARRIER, "barrier" },
1473 { BLK_TC_SYNC, "sync" },
1474 { BLK_TC_QUEUE, "queue" },
1475 { BLK_TC_REQUEUE, "requeue" },
1476 { BLK_TC_ISSUE, "issue" },
1477 { BLK_TC_COMPLETE, "complete" },
1478 { BLK_TC_FS, "fs" },
1479 { BLK_TC_PC, "pc" },
1480 { BLK_TC_AHEAD, "ahead" },
1481 { BLK_TC_META, "meta" },
1482 { BLK_TC_DISCARD, "discard" },
1483 { BLK_TC_DRV_DATA, "drv_data" },
1484 };
1485
1486 static int blk_trace_str2mask(const char *str)
1487 {
1488 int i;
1489 int mask = 0;
1490 char *buf, *s, *token;
1491
1492 buf = kstrdup(str, GFP_KERNEL);
1493 if (buf == NULL)
1494 return -ENOMEM;
1495 s = strstrip(buf);
1496
1497 while (1) {
1498 token = strsep(&s, ",");
1499 if (token == NULL)
1500 break;
1501
1502 if (*token == '\0')
1503 continue;
1504
1505 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1506 if (strcasecmp(token, mask_maps[i].str) == 0) {
1507 mask |= mask_maps[i].mask;
1508 break;
1509 }
1510 }
1511 if (i == ARRAY_SIZE(mask_maps)) {
1512 mask = -EINVAL;
1513 break;
1514 }
1515 }
1516 kfree(buf);
1517
1518 return mask;
1519 }
1520
1521 static ssize_t blk_trace_mask2str(char *buf, int mask)
1522 {
1523 int i;
1524 char *p = buf;
1525
1526 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1527 if (mask & mask_maps[i].mask) {
1528 p += sprintf(p, "%s%s",
1529 (p == buf) ? "" : ",", mask_maps[i].str);
1530 }
1531 }
1532 *p++ = '\n';
1533
1534 return p - buf;
1535 }
1536
1537 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1538 {
1539 if (bdev->bd_disk == NULL)
1540 return NULL;
1541
1542 return bdev_get_queue(bdev);
1543 }
1544
1545 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1546 struct device_attribute *attr,
1547 char *buf)
1548 {
1549 struct hd_struct *p = dev_to_part(dev);
1550 struct request_queue *q;
1551 struct block_device *bdev;
1552 ssize_t ret = -ENXIO;
1553
1554 lock_kernel();
1555 bdev = bdget(part_devt(p));
1556 if (bdev == NULL)
1557 goto out_unlock_kernel;
1558
1559 q = blk_trace_get_queue(bdev);
1560 if (q == NULL)
1561 goto out_bdput;
1562
1563 mutex_lock(&bdev->bd_mutex);
1564
1565 if (attr == &dev_attr_enable) {
1566 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1567 goto out_unlock_bdev;
1568 }
1569
1570 if (q->blk_trace == NULL)
1571 ret = sprintf(buf, "disabled\n");
1572 else if (attr == &dev_attr_act_mask)
1573 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1574 else if (attr == &dev_attr_pid)
1575 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1576 else if (attr == &dev_attr_start_lba)
1577 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1578 else if (attr == &dev_attr_end_lba)
1579 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1580
1581 out_unlock_bdev:
1582 mutex_unlock(&bdev->bd_mutex);
1583 out_bdput:
1584 bdput(bdev);
1585 out_unlock_kernel:
1586 unlock_kernel();
1587 return ret;
1588 }
1589
1590 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1591 struct device_attribute *attr,
1592 const char *buf, size_t count)
1593 {
1594 struct block_device *bdev;
1595 struct request_queue *q;
1596 struct hd_struct *p;
1597 u64 value;
1598 ssize_t ret = -EINVAL;
1599
1600 if (count == 0)
1601 goto out;
1602
1603 if (attr == &dev_attr_act_mask) {
1604 if (sscanf(buf, "%llx", &value) != 1) {
1605 /* Assume it is a list of trace category names */
1606 ret = blk_trace_str2mask(buf);
1607 if (ret < 0)
1608 goto out;
1609 value = ret;
1610 }
1611 } else if (sscanf(buf, "%llu", &value) != 1)
1612 goto out;
1613
1614 ret = -ENXIO;
1615
1616 lock_kernel();
1617 p = dev_to_part(dev);
1618 bdev = bdget(part_devt(p));
1619 if (bdev == NULL)
1620 goto out_unlock_kernel;
1621
1622 q = blk_trace_get_queue(bdev);
1623 if (q == NULL)
1624 goto out_bdput;
1625
1626 mutex_lock(&bdev->bd_mutex);
1627
1628 if (attr == &dev_attr_enable) {
1629 if (value)
1630 ret = blk_trace_setup_queue(q, bdev);
1631 else
1632 ret = blk_trace_remove_queue(q);
1633 goto out_unlock_bdev;
1634 }
1635
1636 ret = 0;
1637 if (q->blk_trace == NULL)
1638 ret = blk_trace_setup_queue(q, bdev);
1639
1640 if (ret == 0) {
1641 if (attr == &dev_attr_act_mask)
1642 q->blk_trace->act_mask = value;
1643 else if (attr == &dev_attr_pid)
1644 q->blk_trace->pid = value;
1645 else if (attr == &dev_attr_start_lba)
1646 q->blk_trace->start_lba = value;
1647 else if (attr == &dev_attr_end_lba)
1648 q->blk_trace->end_lba = value;
1649 }
1650
1651 out_unlock_bdev:
1652 mutex_unlock(&bdev->bd_mutex);
1653 out_bdput:
1654 bdput(bdev);
1655 out_unlock_kernel:
1656 unlock_kernel();
1657 out:
1658 return ret ? ret : count;
1659 }
1660
1661 int blk_trace_init_sysfs(struct device *dev)
1662 {
1663 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1664 }
1665
1666 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1667
1668 #ifdef CONFIG_EVENT_TRACING
1669
1670 void blk_dump_cmd(char *buf, struct request *rq)
1671 {
1672 int i, end;
1673 int len = rq->cmd_len;
1674 unsigned char *cmd = rq->cmd;
1675
1676 if (!blk_pc_request(rq)) {
1677 buf[0] = '\0';
1678 return;
1679 }
1680
1681 for (end = len - 1; end >= 0; end--)
1682 if (cmd[end])
1683 break;
1684 end++;
1685
1686 for (i = 0; i < len; i++) {
1687 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1688 if (i == end && end != len - 1) {
1689 sprintf(buf, " ..");
1690 break;
1691 }
1692 }
1693 }
1694
1695 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1696 {
1697 int i = 0;
1698
1699 if (rw & WRITE)
1700 rwbs[i++] = 'W';
1701 else if (rw & 1 << BIO_RW_DISCARD)
1702 rwbs[i++] = 'D';
1703 else if (bytes)
1704 rwbs[i++] = 'R';
1705 else
1706 rwbs[i++] = 'N';
1707
1708 if (rw & 1 << BIO_RW_AHEAD)
1709 rwbs[i++] = 'A';
1710 if (rw & 1 << BIO_RW_BARRIER)
1711 rwbs[i++] = 'B';
1712 if (rw & 1 << BIO_RW_SYNCIO)
1713 rwbs[i++] = 'S';
1714 if (rw & 1 << BIO_RW_META)
1715 rwbs[i++] = 'M';
1716
1717 rwbs[i] = '\0';
1718 }
1719
1720 void blk_fill_rwbs_rq(char *rwbs, struct request *rq)
1721 {
1722 int rw = rq->cmd_flags & 0x03;
1723 int bytes;
1724
1725 if (blk_discard_rq(rq))
1726 rw |= (1 << BIO_RW_DISCARD);
1727
1728 bytes = blk_rq_bytes(rq);
1729
1730 blk_fill_rwbs(rwbs, rw, bytes);
1731 }
1732
1733 #endif /* CONFIG_EVENT_TRACING */
1734
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