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PCI: PCIe: Move PCIe PME code to the pcie directory
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / trace / blktrace.c
blob959f8d6c8cc1ddad9b994dc08d096be6738fca64
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/smp_lock.h>
27 #include <linux/time.h>
28 #include <linux/uaccess.h>
29
30 #include <trace/events/block.h>
31
32 #include "trace_output.h"
33
34 #ifdef CONFIG_BLK_DEV_IO_TRACE
35
36 static unsigned int blktrace_seq __read_mostly = 1;
37
38 static struct trace_array *blk_tr;
39 static bool blk_tracer_enabled __read_mostly;
40
41 /* Select an alternative, minimalistic output than the original one */
42 #define TRACE_BLK_OPT_CLASSIC 0x1
43
44 static struct tracer_opt blk_tracer_opts[] = {
45 /* Default disable the minimalistic output */
46 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
47 { }
48 };
49
50 static struct tracer_flags blk_tracer_flags = {
51 .val = 0,
52 .opts = blk_tracer_opts,
53 };
54
55 /* Global reference count of probes */
56 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
57
58 static void blk_register_tracepoints(void);
59 static void blk_unregister_tracepoints(void);
60
61 /*
62 * Send out a notify message.
63 */
64 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
65 const void *data, size_t len)
66 {
67 struct blk_io_trace *t;
68 struct ring_buffer_event *event = NULL;
69 struct ring_buffer *buffer = NULL;
70 int pc = 0;
71 int cpu = smp_processor_id();
72 bool blk_tracer = blk_tracer_enabled;
73
74 if (blk_tracer) {
75 buffer = blk_tr->buffer;
76 pc = preempt_count();
77 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
78 sizeof(*t) + len,
79 0, pc);
80 if (!event)
81 return;
82 t = ring_buffer_event_data(event);
83 goto record_it;
84 }
85
86 if (!bt->rchan)
87 return;
88
89 t = relay_reserve(bt->rchan, sizeof(*t) + len);
90 if (t) {
91 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
92 t->time = ktime_to_ns(ktime_get());
93 record_it:
94 t->device = bt->dev;
95 t->action = action;
96 t->pid = pid;
97 t->cpu = cpu;
98 t->pdu_len = len;
99 memcpy((void *) t + sizeof(*t), data, len);
100
101 if (blk_tracer)
102 trace_buffer_unlock_commit(buffer, event, 0, pc);
103 }
104 }
105
106 /*
107 * Send out a notify for this process, if we haven't done so since a trace
108 * started
109 */
110 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
111 {
112 tsk->btrace_seq = blktrace_seq;
113 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
114 }
115
116 static void trace_note_time(struct blk_trace *bt)
117 {
118 struct timespec now;
119 unsigned long flags;
120 u32 words[2];
121
122 getnstimeofday(&now);
123 words[0] = now.tv_sec;
124 words[1] = now.tv_nsec;
125
126 local_irq_save(flags);
127 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
128 local_irq_restore(flags);
129 }
130
131 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
132 {
133 int n;
134 va_list args;
135 unsigned long flags;
136 char *buf;
137
138 if (unlikely(bt->trace_state != Blktrace_running &&
139 !blk_tracer_enabled))
140 return;
141
142 local_irq_save(flags);
143 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
144 va_start(args, fmt);
145 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
146 va_end(args);
147
148 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
149 local_irq_restore(flags);
150 }
151 EXPORT_SYMBOL_GPL(__trace_note_message);
152
153 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
154 pid_t pid)
155 {
156 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
157 return 1;
158 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
159 return 1;
160 if (bt->pid && pid != bt->pid)
161 return 1;
162
163 return 0;
164 }
165
166 /*
167 * Data direction bit lookup
168 */
169 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
170 BLK_TC_ACT(BLK_TC_WRITE) };
171
172 #define BLK_TC_HARDBARRIER BLK_TC_BARRIER
173 #define BLK_TC_RAHEAD BLK_TC_AHEAD
174
175 /* The ilog2() calls fall out because they're constant */
176 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
177 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
178
179 /*
180 * The worker for the various blk_add_trace*() types. Fills out a
181 * blk_io_trace structure and places it in a per-cpu subbuffer.
182 */
183 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
184 int rw, u32 what, int error, int pdu_len, void *pdu_data)
185 {
186 struct task_struct *tsk = current;
187 struct ring_buffer_event *event = NULL;
188 struct ring_buffer *buffer = NULL;
189 struct blk_io_trace *t;
190 unsigned long flags = 0;
191 unsigned long *sequence;
192 pid_t pid;
193 int cpu, pc = 0;
194 bool blk_tracer = blk_tracer_enabled;
195
196 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
197 return;
198
199 what |= ddir_act[rw & WRITE];
200 what |= MASK_TC_BIT(rw, HARDBARRIER);
201 what |= MASK_TC_BIT(rw, SYNC);
202 what |= MASK_TC_BIT(rw, RAHEAD);
203 what |= MASK_TC_BIT(rw, META);
204 what |= MASK_TC_BIT(rw, DISCARD);
205
206 pid = tsk->pid;
207 if (act_log_check(bt, what, sector, pid))
208 return;
209 cpu = raw_smp_processor_id();
210
211 if (blk_tracer) {
212 tracing_record_cmdline(current);
213
214 buffer = blk_tr->buffer;
215 pc = preempt_count();
216 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
217 sizeof(*t) + pdu_len,
218 0, pc);
219 if (!event)
220 return;
221 t = ring_buffer_event_data(event);
222 goto record_it;
223 }
224
225 /*
226 * A word about the locking here - we disable interrupts to reserve
227 * some space in the relay per-cpu buffer, to prevent an irq
228 * from coming in and stepping on our toes.
229 */
230 local_irq_save(flags);
231
232 if (unlikely(tsk->btrace_seq != blktrace_seq))
233 trace_note_tsk(bt, tsk);
234
235 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
236 if (t) {
237 sequence = per_cpu_ptr(bt->sequence, cpu);
238
239 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
240 t->sequence = ++(*sequence);
241 t->time = ktime_to_ns(ktime_get());
242 record_it:
243 /*
244 * These two are not needed in ftrace as they are in the
245 * generic trace_entry, filled by tracing_generic_entry_update,
246 * but for the trace_event->bin() synthesizer benefit we do it
247 * here too.
248 */
249 t->cpu = cpu;
250 t->pid = pid;
251
252 t->sector = sector;
253 t->bytes = bytes;
254 t->action = what;
255 t->device = bt->dev;
256 t->error = error;
257 t->pdu_len = pdu_len;
258
259 if (pdu_len)
260 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
261
262 if (blk_tracer) {
263 trace_buffer_unlock_commit(buffer, event, 0, pc);
264 return;
265 }
266 }
267
268 local_irq_restore(flags);
269 }
270
271 static struct dentry *blk_tree_root;
272 static DEFINE_MUTEX(blk_tree_mutex);
273
274 static void blk_trace_free(struct blk_trace *bt)
275 {
276 debugfs_remove(bt->msg_file);
277 debugfs_remove(bt->dropped_file);
278 relay_close(bt->rchan);
279 debugfs_remove(bt->dir);
280 free_percpu(bt->sequence);
281 free_percpu(bt->msg_data);
282 kfree(bt);
283 }
284
285 static void blk_trace_cleanup(struct blk_trace *bt)
286 {
287 blk_trace_free(bt);
288 if (atomic_dec_and_test(&blk_probes_ref))
289 blk_unregister_tracepoints();
290 }
291
292 int blk_trace_remove(struct request_queue *q)
293 {
294 struct blk_trace *bt;
295
296 bt = xchg(&q->blk_trace, NULL);
297 if (!bt)
298 return -EINVAL;
299
300 if (bt->trace_state != Blktrace_running)
301 blk_trace_cleanup(bt);
302
303 return 0;
304 }
305 EXPORT_SYMBOL_GPL(blk_trace_remove);
306
307 static int blk_dropped_open(struct inode *inode, struct file *filp)
308 {
309 filp->private_data = inode->i_private;
310
311 return 0;
312 }
313
314 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
315 size_t count, loff_t *ppos)
316 {
317 struct blk_trace *bt = filp->private_data;
318 char buf[16];
319
320 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
321
322 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
323 }
324
325 static const struct file_operations blk_dropped_fops = {
326 .owner = THIS_MODULE,
327 .open = blk_dropped_open,
328 .read = blk_dropped_read,
329 };
330
331 static int blk_msg_open(struct inode *inode, struct file *filp)
332 {
333 filp->private_data = inode->i_private;
334
335 return 0;
336 }
337
338 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
339 size_t count, loff_t *ppos)
340 {
341 char *msg;
342 struct blk_trace *bt;
343
344 if (count >= BLK_TN_MAX_MSG)
345 return -EINVAL;
346
347 msg = kmalloc(count + 1, GFP_KERNEL);
348 if (msg == NULL)
349 return -ENOMEM;
350
351 if (copy_from_user(msg, buffer, count)) {
352 kfree(msg);
353 return -EFAULT;
354 }
355
356 msg[count] = '\0';
357 bt = filp->private_data;
358 __trace_note_message(bt, "%s", msg);
359 kfree(msg);
360
361 return count;
362 }
363
364 static const struct file_operations blk_msg_fops = {
365 .owner = THIS_MODULE,
366 .open = blk_msg_open,
367 .write = blk_msg_write,
368 };
369
370 /*
371 * Keep track of how many times we encountered a full subbuffer, to aid
372 * the user space app in telling how many lost events there were.
373 */
374 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
375 void *prev_subbuf, size_t prev_padding)
376 {
377 struct blk_trace *bt;
378
379 if (!relay_buf_full(buf))
380 return 1;
381
382 bt = buf->chan->private_data;
383 atomic_inc(&bt->dropped);
384 return 0;
385 }
386
387 static int blk_remove_buf_file_callback(struct dentry *dentry)
388 {
389 debugfs_remove(dentry);
390
391 return 0;
392 }
393
394 static struct dentry *blk_create_buf_file_callback(const char *filename,
395 struct dentry *parent,
396 int mode,
397 struct rchan_buf *buf,
398 int *is_global)
399 {
400 return debugfs_create_file(filename, mode, parent, buf,
401 &relay_file_operations);
402 }
403
404 static struct rchan_callbacks blk_relay_callbacks = {
405 .subbuf_start = blk_subbuf_start_callback,
406 .create_buf_file = blk_create_buf_file_callback,
407 .remove_buf_file = blk_remove_buf_file_callback,
408 };
409
410 static void blk_trace_setup_lba(struct blk_trace *bt,
411 struct block_device *bdev)
412 {
413 struct hd_struct *part = NULL;
414
415 if (bdev)
416 part = bdev->bd_part;
417
418 if (part) {
419 bt->start_lba = part->start_sect;
420 bt->end_lba = part->start_sect + part->nr_sects;
421 } else {
422 bt->start_lba = 0;
423 bt->end_lba = -1ULL;
424 }
425 }
426
427 /*
428 * Setup everything required to start tracing
429 */
430 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
431 struct block_device *bdev,
432 struct blk_user_trace_setup *buts)
433 {
434 struct blk_trace *old_bt, *bt = NULL;
435 struct dentry *dir = NULL;
436 int ret, i;
437
438 if (!buts->buf_size || !buts->buf_nr)
439 return -EINVAL;
440
441 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
442 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
443
444 /*
445 * some device names have larger paths - convert the slashes
446 * to underscores for this to work as expected
447 */
448 for (i = 0; i < strlen(buts->name); i++)
449 if (buts->name[i] == '/')
450 buts->name[i] = '_';
451
452 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
453 if (!bt)
454 return -ENOMEM;
455
456 ret = -ENOMEM;
457 bt->sequence = alloc_percpu(unsigned long);
458 if (!bt->sequence)
459 goto err;
460
461 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
462 if (!bt->msg_data)
463 goto err;
464
465 ret = -ENOENT;
466
467 mutex_lock(&blk_tree_mutex);
468 if (!blk_tree_root) {
469 blk_tree_root = debugfs_create_dir("block", NULL);
470 if (!blk_tree_root) {
471 mutex_unlock(&blk_tree_mutex);
472 goto err;
473 }
474 }
475 mutex_unlock(&blk_tree_mutex);
476
477 dir = debugfs_create_dir(buts->name, blk_tree_root);
478
479 if (!dir)
480 goto err;
481
482 bt->dir = dir;
483 bt->dev = dev;
484 atomic_set(&bt->dropped, 0);
485
486 ret = -EIO;
487 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
488 &blk_dropped_fops);
489 if (!bt->dropped_file)
490 goto err;
491
492 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
493 if (!bt->msg_file)
494 goto err;
495
496 bt->rchan = relay_open("trace", dir, buts->buf_size,
497 buts->buf_nr, &blk_relay_callbacks, bt);
498 if (!bt->rchan)
499 goto err;
500
501 bt->act_mask = buts->act_mask;
502 if (!bt->act_mask)
503 bt->act_mask = (u16) -1;
504
505 blk_trace_setup_lba(bt, bdev);
506
507 /* overwrite with user settings */
508 if (buts->start_lba)
509 bt->start_lba = buts->start_lba;
510 if (buts->end_lba)
511 bt->end_lba = buts->end_lba;
512
513 bt->pid = buts->pid;
514 bt->trace_state = Blktrace_setup;
515
516 ret = -EBUSY;
517 old_bt = xchg(&q->blk_trace, bt);
518 if (old_bt) {
519 (void) xchg(&q->blk_trace, old_bt);
520 goto err;
521 }
522
523 if (atomic_inc_return(&blk_probes_ref) == 1)
524 blk_register_tracepoints();
525
526 return 0;
527 err:
528 blk_trace_free(bt);
529 return ret;
530 }
531
532 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
533 struct block_device *bdev,
534 char __user *arg)
535 {
536 struct blk_user_trace_setup buts;
537 int ret;
538
539 ret = copy_from_user(&buts, arg, sizeof(buts));
540 if (ret)
541 return -EFAULT;
542
543 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
544 if (ret)
545 return ret;
546
547 if (copy_to_user(arg, &buts, sizeof(buts))) {
548 blk_trace_remove(q);
549 return -EFAULT;
550 }
551 return 0;
552 }
553 EXPORT_SYMBOL_GPL(blk_trace_setup);
554
555 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
556 static int compat_blk_trace_setup(struct request_queue *q, char *name,
557 dev_t dev, struct block_device *bdev,
558 char __user *arg)
559 {
560 struct blk_user_trace_setup buts;
561 struct compat_blk_user_trace_setup cbuts;
562 int ret;
563
564 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
565 return -EFAULT;
566
567 buts = (struct blk_user_trace_setup) {
568 .act_mask = cbuts.act_mask,
569 .buf_size = cbuts.buf_size,
570 .buf_nr = cbuts.buf_nr,
571 .start_lba = cbuts.start_lba,
572 .end_lba = cbuts.end_lba,
573 .pid = cbuts.pid,
574 };
575 memcpy(&buts.name, &cbuts.name, 32);
576
577 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
578 if (ret)
579 return ret;
580
581 if (copy_to_user(arg, &buts.name, 32)) {
582 blk_trace_remove(q);
583 return -EFAULT;
584 }
585
586 return 0;
587 }
588 #endif
589
590 int blk_trace_startstop(struct request_queue *q, int start)
591 {
592 int ret;
593 struct blk_trace *bt = q->blk_trace;
594
595 if (bt == NULL)
596 return -EINVAL;
597
598 /*
599 * For starting a trace, we can transition from a setup or stopped
600 * trace. For stopping a trace, the state must be running
601 */
602 ret = -EINVAL;
603 if (start) {
604 if (bt->trace_state == Blktrace_setup ||
605 bt->trace_state == Blktrace_stopped) {
606 blktrace_seq++;
607 smp_mb();
608 bt->trace_state = Blktrace_running;
609
610 trace_note_time(bt);
611 ret = 0;
612 }
613 } else {
614 if (bt->trace_state == Blktrace_running) {
615 bt->trace_state = Blktrace_stopped;
616 relay_flush(bt->rchan);
617 ret = 0;
618 }
619 }
620
621 return ret;
622 }
623 EXPORT_SYMBOL_GPL(blk_trace_startstop);
624
625 /**
626 * blk_trace_ioctl: - handle the ioctls associated with tracing
627 * @bdev: the block device
628 * @cmd: the ioctl cmd
629 * @arg: the argument data, if any
630 *
631 **/
632 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
633 {
634 struct request_queue *q;
635 int ret, start = 0;
636 char b[BDEVNAME_SIZE];
637
638 q = bdev_get_queue(bdev);
639 if (!q)
640 return -ENXIO;
641
642 lock_kernel();
643 mutex_lock(&bdev->bd_mutex);
644
645 switch (cmd) {
646 case BLKTRACESETUP:
647 bdevname(bdev, b);
648 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
649 break;
650 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
651 case BLKTRACESETUP32:
652 bdevname(bdev, b);
653 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
654 break;
655 #endif
656 case BLKTRACESTART:
657 start = 1;
658 case BLKTRACESTOP:
659 ret = blk_trace_startstop(q, start);
660 break;
661 case BLKTRACETEARDOWN:
662 ret = blk_trace_remove(q);
663 break;
664 default:
665 ret = -ENOTTY;
666 break;
667 }
668
669 mutex_unlock(&bdev->bd_mutex);
670 unlock_kernel();
671 return ret;
672 }
673
674 /**
675 * blk_trace_shutdown: - stop and cleanup trace structures
676 * @q: the request queue associated with the device
677 *
678 **/
679 void blk_trace_shutdown(struct request_queue *q)
680 {
681 if (q->blk_trace) {
682 blk_trace_startstop(q, 0);
683 blk_trace_remove(q);
684 }
685 }
686
687 /*
688 * blktrace probes
689 */
690
691 /**
692 * blk_add_trace_rq - Add a trace for a request oriented action
693 * @q: queue the io is for
694 * @rq: the source request
695 * @what: the action
696 *
697 * Description:
698 * Records an action against a request. Will log the bio offset + size.
699 *
700 **/
701 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
702 u32 what)
703 {
704 struct blk_trace *bt = q->blk_trace;
705 int rw = rq->cmd_flags & 0x03;
706
707 if (likely(!bt))
708 return;
709
710 if (rq->cmd_flags & REQ_DISCARD)
711 rw |= REQ_DISCARD;
712
713 if (rq->cmd_flags & REQ_SECURE)
714 rw |= REQ_SECURE;
715
716 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
717 what |= BLK_TC_ACT(BLK_TC_PC);
718 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
719 what, rq->errors, rq->cmd_len, rq->cmd);
720 } else {
721 what |= BLK_TC_ACT(BLK_TC_FS);
722 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
723 what, rq->errors, 0, NULL);
724 }
725 }
726
727 static void blk_add_trace_rq_abort(void *ignore,
728 struct request_queue *q, struct request *rq)
729 {
730 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
731 }
732
733 static void blk_add_trace_rq_insert(void *ignore,
734 struct request_queue *q, struct request *rq)
735 {
736 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
737 }
738
739 static void blk_add_trace_rq_issue(void *ignore,
740 struct request_queue *q, struct request *rq)
741 {
742 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
743 }
744
745 static void blk_add_trace_rq_requeue(void *ignore,
746 struct request_queue *q,
747 struct request *rq)
748 {
749 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
750 }
751
752 static void blk_add_trace_rq_complete(void *ignore,
753 struct request_queue *q,
754 struct request *rq)
755 {
756 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
757 }
758
759 /**
760 * blk_add_trace_bio - Add a trace for a bio oriented action
761 * @q: queue the io is for
762 * @bio: the source bio
763 * @what: the action
764 *
765 * Description:
766 * Records an action against a bio. Will log the bio offset + size.
767 *
768 **/
769 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
770 u32 what)
771 {
772 struct blk_trace *bt = q->blk_trace;
773
774 if (likely(!bt))
775 return;
776
777 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
778 !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
779 }
780
781 static void blk_add_trace_bio_bounce(void *ignore,
782 struct request_queue *q, struct bio *bio)
783 {
784 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
785 }
786
787 static void blk_add_trace_bio_complete(void *ignore,
788 struct request_queue *q, struct bio *bio)
789 {
790 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
791 }
792
793 static void blk_add_trace_bio_backmerge(void *ignore,
794 struct request_queue *q,
795 struct bio *bio)
796 {
797 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
798 }
799
800 static void blk_add_trace_bio_frontmerge(void *ignore,
801 struct request_queue *q,
802 struct bio *bio)
803 {
804 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
805 }
806
807 static void blk_add_trace_bio_queue(void *ignore,
808 struct request_queue *q, struct bio *bio)
809 {
810 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
811 }
812
813 static void blk_add_trace_getrq(void *ignore,
814 struct request_queue *q,
815 struct bio *bio, int rw)
816 {
817 if (bio)
818 blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
819 else {
820 struct blk_trace *bt = q->blk_trace;
821
822 if (bt)
823 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
824 }
825 }
826
827
828 static void blk_add_trace_sleeprq(void *ignore,
829 struct request_queue *q,
830 struct bio *bio, int rw)
831 {
832 if (bio)
833 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
834 else {
835 struct blk_trace *bt = q->blk_trace;
836
837 if (bt)
838 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
839 0, 0, NULL);
840 }
841 }
842
843 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
844 {
845 struct blk_trace *bt = q->blk_trace;
846
847 if (bt)
848 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
849 }
850
851 static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q)
852 {
853 struct blk_trace *bt = q->blk_trace;
854
855 if (bt) {
856 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
857 __be64 rpdu = cpu_to_be64(pdu);
858
859 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
860 sizeof(rpdu), &rpdu);
861 }
862 }
863
864 static void blk_add_trace_unplug_timer(void *ignore, struct request_queue *q)
865 {
866 struct blk_trace *bt = q->blk_trace;
867
868 if (bt) {
869 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
870 __be64 rpdu = cpu_to_be64(pdu);
871
872 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
873 sizeof(rpdu), &rpdu);
874 }
875 }
876
877 static void blk_add_trace_split(void *ignore,
878 struct request_queue *q, struct bio *bio,
879 unsigned int pdu)
880 {
881 struct blk_trace *bt = q->blk_trace;
882
883 if (bt) {
884 __be64 rpdu = cpu_to_be64(pdu);
885
886 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
887 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
888 sizeof(rpdu), &rpdu);
889 }
890 }
891
892 /**
893 * blk_add_trace_remap - Add a trace for a remap operation
894 * @ignore: trace callback data parameter (not used)
895 * @q: queue the io is for
896 * @bio: the source bio
897 * @dev: target device
898 * @from: source sector
899 *
900 * Description:
901 * Device mapper or raid target sometimes need to split a bio because
902 * it spans a stripe (or similar). Add a trace for that action.
903 *
904 **/
905 static void blk_add_trace_remap(void *ignore,
906 struct request_queue *q, struct bio *bio,
907 dev_t dev, sector_t from)
908 {
909 struct blk_trace *bt = q->blk_trace;
910 struct blk_io_trace_remap r;
911
912 if (likely(!bt))
913 return;
914
915 r.device_from = cpu_to_be32(dev);
916 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
917 r.sector_from = cpu_to_be64(from);
918
919 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
920 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
921 sizeof(r), &r);
922 }
923
924 /**
925 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
926 * @ignore: trace callback data parameter (not used)
927 * @q: queue the io is for
928 * @rq: the source request
929 * @dev: target device
930 * @from: source sector
931 *
932 * Description:
933 * Device mapper remaps request to other devices.
934 * Add a trace for that action.
935 *
936 **/
937 static void blk_add_trace_rq_remap(void *ignore,
938 struct request_queue *q,
939 struct request *rq, dev_t dev,
940 sector_t from)
941 {
942 struct blk_trace *bt = q->blk_trace;
943 struct blk_io_trace_remap r;
944
945 if (likely(!bt))
946 return;
947
948 r.device_from = cpu_to_be32(dev);
949 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
950 r.sector_from = cpu_to_be64(from);
951
952 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
953 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
954 sizeof(r), &r);
955 }
956
957 /**
958 * blk_add_driver_data - Add binary message with driver-specific data
959 * @q: queue the io is for
960 * @rq: io request
961 * @data: driver-specific data
962 * @len: length of driver-specific data
963 *
964 * Description:
965 * Some drivers might want to write driver-specific data per request.
966 *
967 **/
968 void blk_add_driver_data(struct request_queue *q,
969 struct request *rq,
970 void *data, size_t len)
971 {
972 struct blk_trace *bt = q->blk_trace;
973
974 if (likely(!bt))
975 return;
976
977 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
978 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
979 BLK_TA_DRV_DATA, rq->errors, len, data);
980 else
981 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
982 BLK_TA_DRV_DATA, rq->errors, len, data);
983 }
984 EXPORT_SYMBOL_GPL(blk_add_driver_data);
985
986 static void blk_register_tracepoints(void)
987 {
988 int ret;
989
990 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
991 WARN_ON(ret);
992 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
993 WARN_ON(ret);
994 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
995 WARN_ON(ret);
996 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
997 WARN_ON(ret);
998 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
999 WARN_ON(ret);
1000 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1001 WARN_ON(ret);
1002 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1003 WARN_ON(ret);
1004 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1005 WARN_ON(ret);
1006 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1007 WARN_ON(ret);
1008 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1009 WARN_ON(ret);
1010 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1011 WARN_ON(ret);
1012 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1013 WARN_ON(ret);
1014 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1015 WARN_ON(ret);
1016 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
1017 WARN_ON(ret);
1018 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
1019 WARN_ON(ret);
1020 ret = register_trace_block_split(blk_add_trace_split, NULL);
1021 WARN_ON(ret);
1022 ret = register_trace_block_remap(blk_add_trace_remap, NULL);
1023 WARN_ON(ret);
1024 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1025 WARN_ON(ret);
1026 }
1027
1028 static void blk_unregister_tracepoints(void)
1029 {
1030 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1031 unregister_trace_block_remap(blk_add_trace_remap, NULL);
1032 unregister_trace_block_split(blk_add_trace_split, NULL);
1033 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
1034 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
1035 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1036 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1037 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1038 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1039 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1040 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1041 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1042 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1043 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1044 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1045 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1046 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1047 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1048
1049 tracepoint_synchronize_unregister();
1050 }
1051
1052 /*
1053 * struct blk_io_tracer formatting routines
1054 */
1055
1056 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1057 {
1058 int i = 0;
1059 int tc = t->action >> BLK_TC_SHIFT;
1060
1061 if (t->action == BLK_TN_MESSAGE) {
1062 rwbs[i++] = 'N';
1063 goto out;
1064 }
1065
1066 if (tc & BLK_TC_DISCARD)
1067 rwbs[i++] = 'D';
1068 else if (tc & BLK_TC_WRITE)
1069 rwbs[i++] = 'W';
1070 else if (t->bytes)
1071 rwbs[i++] = 'R';
1072 else
1073 rwbs[i++] = 'N';
1074
1075 if (tc & BLK_TC_AHEAD)
1076 rwbs[i++] = 'A';
1077 if (tc & BLK_TC_BARRIER)
1078 rwbs[i++] = 'B';
1079 if (tc & BLK_TC_SYNC)
1080 rwbs[i++] = 'S';
1081 if (tc & BLK_TC_META)
1082 rwbs[i++] = 'M';
1083 out:
1084 rwbs[i] = '\0';
1085 }
1086
1087 static inline
1088 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1089 {
1090 return (const struct blk_io_trace *)ent;
1091 }
1092
1093 static inline const void *pdu_start(const struct trace_entry *ent)
1094 {
1095 return te_blk_io_trace(ent) + 1;
1096 }
1097
1098 static inline u32 t_action(const struct trace_entry *ent)
1099 {
1100 return te_blk_io_trace(ent)->action;
1101 }
1102
1103 static inline u32 t_bytes(const struct trace_entry *ent)
1104 {
1105 return te_blk_io_trace(ent)->bytes;
1106 }
1107
1108 static inline u32 t_sec(const struct trace_entry *ent)
1109 {
1110 return te_blk_io_trace(ent)->bytes >> 9;
1111 }
1112
1113 static inline unsigned long long t_sector(const struct trace_entry *ent)
1114 {
1115 return te_blk_io_trace(ent)->sector;
1116 }
1117
1118 static inline __u16 t_error(const struct trace_entry *ent)
1119 {
1120 return te_blk_io_trace(ent)->error;
1121 }
1122
1123 static __u64 get_pdu_int(const struct trace_entry *ent)
1124 {
1125 const __u64 *val = pdu_start(ent);
1126 return be64_to_cpu(*val);
1127 }
1128
1129 static void get_pdu_remap(const struct trace_entry *ent,
1130 struct blk_io_trace_remap *r)
1131 {
1132 const struct blk_io_trace_remap *__r = pdu_start(ent);
1133 __u64 sector_from = __r->sector_from;
1134
1135 r->device_from = be32_to_cpu(__r->device_from);
1136 r->device_to = be32_to_cpu(__r->device_to);
1137 r->sector_from = be64_to_cpu(sector_from);
1138 }
1139
1140 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1141
1142 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1143 {
1144 char rwbs[6];
1145 unsigned long long ts = iter->ts;
1146 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1147 unsigned secs = (unsigned long)ts;
1148 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1149
1150 fill_rwbs(rwbs, t);
1151
1152 return trace_seq_printf(&iter->seq,
1153 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1154 MAJOR(t->device), MINOR(t->device), iter->cpu,
1155 secs, nsec_rem, iter->ent->pid, act, rwbs);
1156 }
1157
1158 static int blk_log_action(struct trace_iterator *iter, const char *act)
1159 {
1160 char rwbs[6];
1161 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1162
1163 fill_rwbs(rwbs, t);
1164 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1165 MAJOR(t->device), MINOR(t->device), act, rwbs);
1166 }
1167
1168 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1169 {
1170 const unsigned char *pdu_buf;
1171 int pdu_len;
1172 int i, end, ret;
1173
1174 pdu_buf = pdu_start(ent);
1175 pdu_len = te_blk_io_trace(ent)->pdu_len;
1176
1177 if (!pdu_len)
1178 return 1;
1179
1180 /* find the last zero that needs to be printed */
1181 for (end = pdu_len - 1; end >= 0; end--)
1182 if (pdu_buf[end])
1183 break;
1184 end++;
1185
1186 if (!trace_seq_putc(s, '('))
1187 return 0;
1188
1189 for (i = 0; i < pdu_len; i++) {
1190
1191 ret = trace_seq_printf(s, "%s%02x",
1192 i == 0 ? "" : " ", pdu_buf[i]);
1193 if (!ret)
1194 return ret;
1195
1196 /*
1197 * stop when the rest is just zeroes and indicate so
1198 * with a ".." appended
1199 */
1200 if (i == end && end != pdu_len - 1)
1201 return trace_seq_puts(s, " ..) ");
1202 }
1203
1204 return trace_seq_puts(s, ") ");
1205 }
1206
1207 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1208 {
1209 char cmd[TASK_COMM_LEN];
1210
1211 trace_find_cmdline(ent->pid, cmd);
1212
1213 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1214 int ret;
1215
1216 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1217 if (!ret)
1218 return 0;
1219 ret = blk_log_dump_pdu(s, ent);
1220 if (!ret)
1221 return 0;
1222 return trace_seq_printf(s, "[%s]\n", cmd);
1223 } else {
1224 if (t_sec(ent))
1225 return trace_seq_printf(s, "%llu + %u [%s]\n",
1226 t_sector(ent), t_sec(ent), cmd);
1227 return trace_seq_printf(s, "[%s]\n", cmd);
1228 }
1229 }
1230
1231 static int blk_log_with_error(struct trace_seq *s,
1232 const struct trace_entry *ent)
1233 {
1234 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1235 int ret;
1236
1237 ret = blk_log_dump_pdu(s, ent);
1238 if (ret)
1239 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1240 return 0;
1241 } else {
1242 if (t_sec(ent))
1243 return trace_seq_printf(s, "%llu + %u [%d]\n",
1244 t_sector(ent),
1245 t_sec(ent), t_error(ent));
1246 return trace_seq_printf(s, "%llu [%d]\n",
1247 t_sector(ent), t_error(ent));
1248 }
1249 }
1250
1251 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1252 {
1253 struct blk_io_trace_remap r = { .device_from = 0, };
1254
1255 get_pdu_remap(ent, &r);
1256 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1257 t_sector(ent), t_sec(ent),
1258 MAJOR(r.device_from), MINOR(r.device_from),
1259 (unsigned long long)r.sector_from);
1260 }
1261
1262 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1263 {
1264 char cmd[TASK_COMM_LEN];
1265
1266 trace_find_cmdline(ent->pid, cmd);
1267
1268 return trace_seq_printf(s, "[%s]\n", cmd);
1269 }
1270
1271 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1272 {
1273 char cmd[TASK_COMM_LEN];
1274
1275 trace_find_cmdline(ent->pid, cmd);
1276
1277 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1278 }
1279
1280 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1281 {
1282 char cmd[TASK_COMM_LEN];
1283
1284 trace_find_cmdline(ent->pid, cmd);
1285
1286 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1287 get_pdu_int(ent), cmd);
1288 }
1289
1290 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1291 {
1292 int ret;
1293 const struct blk_io_trace *t = te_blk_io_trace(ent);
1294
1295 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1296 if (ret)
1297 return trace_seq_putc(s, '\n');
1298 return ret;
1299 }
1300
1301 /*
1302 * struct tracer operations
1303 */
1304
1305 static void blk_tracer_print_header(struct seq_file *m)
1306 {
1307 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1308 return;
1309 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1310 "# | | | | | |\n");
1311 }
1312
1313 static void blk_tracer_start(struct trace_array *tr)
1314 {
1315 blk_tracer_enabled = true;
1316 }
1317
1318 static int blk_tracer_init(struct trace_array *tr)
1319 {
1320 blk_tr = tr;
1321 blk_tracer_start(tr);
1322 return 0;
1323 }
1324
1325 static void blk_tracer_stop(struct trace_array *tr)
1326 {
1327 blk_tracer_enabled = false;
1328 }
1329
1330 static void blk_tracer_reset(struct trace_array *tr)
1331 {
1332 blk_tracer_stop(tr);
1333 }
1334
1335 static const struct {
1336 const char *act[2];
1337 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1338 } what2act[] = {
1339 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1340 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1341 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1342 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1343 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1344 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1345 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1346 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1347 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1348 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1349 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1350 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1351 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1352 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1353 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1354 };
1355
1356 static enum print_line_t print_one_line(struct trace_iterator *iter,
1357 bool classic)
1358 {
1359 struct trace_seq *s = &iter->seq;
1360 const struct blk_io_trace *t;
1361 u16 what;
1362 int ret;
1363 bool long_act;
1364 blk_log_action_t *log_action;
1365
1366 t = te_blk_io_trace(iter->ent);
1367 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1368 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1369 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1370
1371 if (t->action == BLK_TN_MESSAGE) {
1372 ret = log_action(iter, long_act ? "message" : "m");
1373 if (ret)
1374 ret = blk_log_msg(s, iter->ent);
1375 goto out;
1376 }
1377
1378 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1379 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1380 else {
1381 ret = log_action(iter, what2act[what].act[long_act]);
1382 if (ret)
1383 ret = what2act[what].print(s, iter->ent);
1384 }
1385 out:
1386 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1387 }
1388
1389 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1390 int flags, struct trace_event *event)
1391 {
1392 return print_one_line(iter, false);
1393 }
1394
1395 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1396 {
1397 struct trace_seq *s = &iter->seq;
1398 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1399 const int offset = offsetof(struct blk_io_trace, sector);
1400 struct blk_io_trace old = {
1401 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1402 .time = iter->ts,
1403 };
1404
1405 if (!trace_seq_putmem(s, &old, offset))
1406 return 0;
1407 return trace_seq_putmem(s, &t->sector,
1408 sizeof(old) - offset + t->pdu_len);
1409 }
1410
1411 static enum print_line_t
1412 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1413 struct trace_event *event)
1414 {
1415 return blk_trace_synthesize_old_trace(iter) ?
1416 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1417 }
1418
1419 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1420 {
1421 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1422 return TRACE_TYPE_UNHANDLED;
1423
1424 return print_one_line(iter, true);
1425 }
1426
1427 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1428 {
1429 /* don't output context-info for blk_classic output */
1430 if (bit == TRACE_BLK_OPT_CLASSIC) {
1431 if (set)
1432 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1433 else
1434 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1435 }
1436 return 0;
1437 }
1438
1439 static struct tracer blk_tracer __read_mostly = {
1440 .name = "blk",
1441 .init = blk_tracer_init,
1442 .reset = blk_tracer_reset,
1443 .start = blk_tracer_start,
1444 .stop = blk_tracer_stop,
1445 .print_header = blk_tracer_print_header,
1446 .print_line = blk_tracer_print_line,
1447 .flags = &blk_tracer_flags,
1448 .set_flag = blk_tracer_set_flag,
1449 };
1450
1451 static struct trace_event_functions trace_blk_event_funcs = {
1452 .trace = blk_trace_event_print,
1453 .binary = blk_trace_event_print_binary,
1454 };
1455
1456 static struct trace_event trace_blk_event = {
1457 .type = TRACE_BLK,
1458 .funcs = &trace_blk_event_funcs,
1459 };
1460
1461 static int __init init_blk_tracer(void)
1462 {
1463 if (!register_ftrace_event(&trace_blk_event)) {
1464 pr_warning("Warning: could not register block events\n");
1465 return 1;
1466 }
1467
1468 if (register_tracer(&blk_tracer) != 0) {
1469 pr_warning("Warning: could not register the block tracer\n");
1470 unregister_ftrace_event(&trace_blk_event);
1471 return 1;
1472 }
1473
1474 return 0;
1475 }
1476
1477 device_initcall(init_blk_tracer);
1478
1479 static int blk_trace_remove_queue(struct request_queue *q)
1480 {
1481 struct blk_trace *bt;
1482
1483 bt = xchg(&q->blk_trace, NULL);
1484 if (bt == NULL)
1485 return -EINVAL;
1486
1487 if (atomic_dec_and_test(&blk_probes_ref))
1488 blk_unregister_tracepoints();
1489
1490 blk_trace_free(bt);
1491 return 0;
1492 }
1493
1494 /*
1495 * Setup everything required to start tracing
1496 */
1497 static int blk_trace_setup_queue(struct request_queue *q,
1498 struct block_device *bdev)
1499 {
1500 struct blk_trace *old_bt, *bt = NULL;
1501 int ret = -ENOMEM;
1502
1503 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1504 if (!bt)
1505 return -ENOMEM;
1506
1507 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1508 if (!bt->msg_data)
1509 goto free_bt;
1510
1511 bt->dev = bdev->bd_dev;
1512 bt->act_mask = (u16)-1;
1513
1514 blk_trace_setup_lba(bt, bdev);
1515
1516 old_bt = xchg(&q->blk_trace, bt);
1517 if (old_bt != NULL) {
1518 (void)xchg(&q->blk_trace, old_bt);
1519 ret = -EBUSY;
1520 goto free_bt;
1521 }
1522
1523 if (atomic_inc_return(&blk_probes_ref) == 1)
1524 blk_register_tracepoints();
1525 return 0;
1526
1527 free_bt:
1528 blk_trace_free(bt);
1529 return ret;
1530 }
1531
1532 /*
1533 * sysfs interface to enable and configure tracing
1534 */
1535
1536 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1537 struct device_attribute *attr,
1538 char *buf);
1539 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1540 struct device_attribute *attr,
1541 const char *buf, size_t count);
1542 #define BLK_TRACE_DEVICE_ATTR(_name) \
1543 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1544 sysfs_blk_trace_attr_show, \
1545 sysfs_blk_trace_attr_store)
1546
1547 static BLK_TRACE_DEVICE_ATTR(enable);
1548 static BLK_TRACE_DEVICE_ATTR(act_mask);
1549 static BLK_TRACE_DEVICE_ATTR(pid);
1550 static BLK_TRACE_DEVICE_ATTR(start_lba);
1551 static BLK_TRACE_DEVICE_ATTR(end_lba);
1552
1553 static struct attribute *blk_trace_attrs[] = {
1554 &dev_attr_enable.attr,
1555 &dev_attr_act_mask.attr,
1556 &dev_attr_pid.attr,
1557 &dev_attr_start_lba.attr,
1558 &dev_attr_end_lba.attr,
1559 NULL
1560 };
1561
1562 struct attribute_group blk_trace_attr_group = {
1563 .name = "trace",
1564 .attrs = blk_trace_attrs,
1565 };
1566
1567 static const struct {
1568 int mask;
1569 const char *str;
1570 } mask_maps[] = {
1571 { BLK_TC_READ, "read" },
1572 { BLK_TC_WRITE, "write" },
1573 { BLK_TC_BARRIER, "barrier" },
1574 { BLK_TC_SYNC, "sync" },
1575 { BLK_TC_QUEUE, "queue" },
1576 { BLK_TC_REQUEUE, "requeue" },
1577 { BLK_TC_ISSUE, "issue" },
1578 { BLK_TC_COMPLETE, "complete" },
1579 { BLK_TC_FS, "fs" },
1580 { BLK_TC_PC, "pc" },
1581 { BLK_TC_AHEAD, "ahead" },
1582 { BLK_TC_META, "meta" },
1583 { BLK_TC_DISCARD, "discard" },
1584 { BLK_TC_DRV_DATA, "drv_data" },
1585 };
1586
1587 static int blk_trace_str2mask(const char *str)
1588 {
1589 int i;
1590 int mask = 0;
1591 char *buf, *s, *token;
1592
1593 buf = kstrdup(str, GFP_KERNEL);
1594 if (buf == NULL)
1595 return -ENOMEM;
1596 s = strstrip(buf);
1597
1598 while (1) {
1599 token = strsep(&s, ",");
1600 if (token == NULL)
1601 break;
1602
1603 if (*token == '\0')
1604 continue;
1605
1606 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1607 if (strcasecmp(token, mask_maps[i].str) == 0) {
1608 mask |= mask_maps[i].mask;
1609 break;
1610 }
1611 }
1612 if (i == ARRAY_SIZE(mask_maps)) {
1613 mask = -EINVAL;
1614 break;
1615 }
1616 }
1617 kfree(buf);
1618
1619 return mask;
1620 }
1621
1622 static ssize_t blk_trace_mask2str(char *buf, int mask)
1623 {
1624 int i;
1625 char *p = buf;
1626
1627 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1628 if (mask & mask_maps[i].mask) {
1629 p += sprintf(p, "%s%s",
1630 (p == buf) ? "" : ",", mask_maps[i].str);
1631 }
1632 }
1633 *p++ = '\n';
1634
1635 return p - buf;
1636 }
1637
1638 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1639 {
1640 if (bdev->bd_disk == NULL)
1641 return NULL;
1642
1643 return bdev_get_queue(bdev);
1644 }
1645
1646 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1647 struct device_attribute *attr,
1648 char *buf)
1649 {
1650 struct hd_struct *p = dev_to_part(dev);
1651 struct request_queue *q;
1652 struct block_device *bdev;
1653 ssize_t ret = -ENXIO;
1654
1655 lock_kernel();
1656 bdev = bdget(part_devt(p));
1657 if (bdev == NULL)
1658 goto out_unlock_kernel;
1659
1660 q = blk_trace_get_queue(bdev);
1661 if (q == NULL)
1662 goto out_bdput;
1663
1664 mutex_lock(&bdev->bd_mutex);
1665
1666 if (attr == &dev_attr_enable) {
1667 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1668 goto out_unlock_bdev;
1669 }
1670
1671 if (q->blk_trace == NULL)
1672 ret = sprintf(buf, "disabled\n");
1673 else if (attr == &dev_attr_act_mask)
1674 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1675 else if (attr == &dev_attr_pid)
1676 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1677 else if (attr == &dev_attr_start_lba)
1678 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1679 else if (attr == &dev_attr_end_lba)
1680 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1681
1682 out_unlock_bdev:
1683 mutex_unlock(&bdev->bd_mutex);
1684 out_bdput:
1685 bdput(bdev);
1686 out_unlock_kernel:
1687 unlock_kernel();
1688 return ret;
1689 }
1690
1691 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1692 struct device_attribute *attr,
1693 const char *buf, size_t count)
1694 {
1695 struct block_device *bdev;
1696 struct request_queue *q;
1697 struct hd_struct *p;
1698 u64 value;
1699 ssize_t ret = -EINVAL;
1700
1701 if (count == 0)
1702 goto out;
1703
1704 if (attr == &dev_attr_act_mask) {
1705 if (sscanf(buf, "%llx", &value) != 1) {
1706 /* Assume it is a list of trace category names */
1707 ret = blk_trace_str2mask(buf);
1708 if (ret < 0)
1709 goto out;
1710 value = ret;
1711 }
1712 } else if (sscanf(buf, "%llu", &value) != 1)
1713 goto out;
1714
1715 ret = -ENXIO;
1716
1717 lock_kernel();
1718 p = dev_to_part(dev);
1719 bdev = bdget(part_devt(p));
1720 if (bdev == NULL)
1721 goto out_unlock_kernel;
1722
1723 q = blk_trace_get_queue(bdev);
1724 if (q == NULL)
1725 goto out_bdput;
1726
1727 mutex_lock(&bdev->bd_mutex);
1728
1729 if (attr == &dev_attr_enable) {
1730 if (value)
1731 ret = blk_trace_setup_queue(q, bdev);
1732 else
1733 ret = blk_trace_remove_queue(q);
1734 goto out_unlock_bdev;
1735 }
1736
1737 ret = 0;
1738 if (q->blk_trace == NULL)
1739 ret = blk_trace_setup_queue(q, bdev);
1740
1741 if (ret == 0) {
1742 if (attr == &dev_attr_act_mask)
1743 q->blk_trace->act_mask = value;
1744 else if (attr == &dev_attr_pid)
1745 q->blk_trace->pid = value;
1746 else if (attr == &dev_attr_start_lba)
1747 q->blk_trace->start_lba = value;
1748 else if (attr == &dev_attr_end_lba)
1749 q->blk_trace->end_lba = value;
1750 }
1751
1752 out_unlock_bdev:
1753 mutex_unlock(&bdev->bd_mutex);
1754 out_bdput:
1755 bdput(bdev);
1756 out_unlock_kernel:
1757 unlock_kernel();
1758 out:
1759 return ret ? ret : count;
1760 }
1761
1762 int blk_trace_init_sysfs(struct device *dev)
1763 {
1764 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1765 }
1766
1767 void blk_trace_remove_sysfs(struct device *dev)
1768 {
1769 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1770 }
1771
1772 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1773
1774 #ifdef CONFIG_EVENT_TRACING
1775
1776 void blk_dump_cmd(char *buf, struct request *rq)
1777 {
1778 int i, end;
1779 int len = rq->cmd_len;
1780 unsigned char *cmd = rq->cmd;
1781
1782 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1783 buf[0] = '\0';
1784 return;
1785 }
1786
1787 for (end = len - 1; end >= 0; end--)
1788 if (cmd[end])
1789 break;
1790 end++;
1791
1792 for (i = 0; i < len; i++) {
1793 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1794 if (i == end && end != len - 1) {
1795 sprintf(buf, " ..");
1796 break;
1797 }
1798 }
1799 }
1800
1801 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1802 {
1803 int i = 0;
1804
1805 if (rw & WRITE)
1806 rwbs[i++] = 'W';
1807 else if (rw & REQ_DISCARD)
1808 rwbs[i++] = 'D';
1809 else if (bytes)
1810 rwbs[i++] = 'R';
1811 else
1812 rwbs[i++] = 'N';
1813
1814 if (rw & REQ_RAHEAD)
1815 rwbs[i++] = 'A';
1816 if (rw & REQ_HARDBARRIER)
1817 rwbs[i++] = 'B';
1818 if (rw & REQ_SYNC)
1819 rwbs[i++] = 'S';
1820 if (rw & REQ_META)
1821 rwbs[i++] = 'M';
1822 if (rw & REQ_SECURE)
1823 rwbs[i++] = 'E';
1824
1825 rwbs[i] = '\0';
1826 }
1827
1828 void blk_fill_rwbs_rq(char *rwbs, struct request *rq)
1829 {
1830 int rw = rq->cmd_flags & 0x03;
1831 int bytes;
1832
1833 if (rq->cmd_flags & REQ_DISCARD)
1834 rw |= REQ_DISCARD;
1835
1836 if (rq->cmd_flags & REQ_SECURE)
1837 rw |= REQ_SECURE;
1838
1839 bytes = blk_rq_bytes(rq);
1840
1841 blk_fill_rwbs(rwbs, rw, bytes);
1842 }
1843
1844 #endif /* CONFIG_EVENT_TRACING */
1845
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