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-rw-r--r--kernel/trace/blktrace.c1550
1 files changed, 1550 insertions, 0 deletions
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
new file mode 100644
index 000000000000..b32ff446c3fb
--- /dev/null
+++ b/kernel/trace/blktrace.c
@@ -0,0 +1,1550 @@
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/time.h>
26#include <trace/block.h>
27#include <linux/uaccess.h>
28#include "trace_output.h"
29
30static unsigned int blktrace_seq __read_mostly = 1;
31
32static struct trace_array *blk_tr;
33static bool blk_tracer_enabled __read_mostly;
34
35/* Select an alternative, minimalistic output than the original one */
36#define TRACE_BLK_OPT_CLASSIC 0x1
37
38static struct tracer_opt blk_tracer_opts[] = {
39 /* Default disable the minimalistic output */
40 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
41 { }
42};
43
44static struct tracer_flags blk_tracer_flags = {
45 .val = 0,
46 .opts = blk_tracer_opts,
47};
48
49/* Global reference count of probes */
50static atomic_t blk_probes_ref = ATOMIC_INIT(0);
51
52static void blk_register_tracepoints(void);
53static void blk_unregister_tracepoints(void);
54
55/*
56 * Send out a notify message.
57 */
58static void trace_note(struct blk_trace *bt, pid_t pid, int action,
59 const void *data, size_t len)
60{
61 struct blk_io_trace *t;
62 struct ring_buffer_event *event = NULL;
63 int pc = 0;
64 int cpu = smp_processor_id();
65 bool blk_tracer = blk_tracer_enabled;
66
67 if (blk_tracer) {
68 pc = preempt_count();
69 event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
70 sizeof(*t) + len,
71 0, pc);
72 if (!event)
73 return;
74 t = ring_buffer_event_data(event);
75 goto record_it;
76 }
77
78 if (!bt->rchan)
79 return;
80
81 t = relay_reserve(bt->rchan, sizeof(*t) + len);
82 if (t) {
83 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
84 t->time = ktime_to_ns(ktime_get());
85record_it:
86 t->device = bt->dev;
87 t->action = action;
88 t->pid = pid;
89 t->cpu = cpu;
90 t->pdu_len = len;
91 memcpy((void *) t + sizeof(*t), data, len);
92
93 if (blk_tracer)
94 trace_buffer_unlock_commit(blk_tr, event, 0, pc);
95 }
96}
97
98/*
99 * Send out a notify for this process, if we haven't done so since a trace
100 * started
101 */
102static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
103{
104 tsk->btrace_seq = blktrace_seq;
105 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
106}
107
108static void trace_note_time(struct blk_trace *bt)
109{
110 struct timespec now;
111 unsigned long flags;
112 u32 words[2];
113
114 getnstimeofday(&now);
115 words[0] = now.tv_sec;
116 words[1] = now.tv_nsec;
117
118 local_irq_save(flags);
119 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
120 local_irq_restore(flags);
121}
122
123void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
124{
125 int n;
126 va_list args;
127 unsigned long flags;
128 char *buf;
129
130 if (unlikely(bt->trace_state != Blktrace_running &&
131 !blk_tracer_enabled))
132 return;
133
134 local_irq_save(flags);
135 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
136 va_start(args, fmt);
137 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
138 va_end(args);
139
140 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
141 local_irq_restore(flags);
142}
143EXPORT_SYMBOL_GPL(__trace_note_message);
144
145static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
146 pid_t pid)
147{
148 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
149 return 1;
150 if (sector < bt->start_lba || sector > bt->end_lba)
151 return 1;
152 if (bt->pid && pid != bt->pid)
153 return 1;
154
155 return 0;
156}
157
158/*
159 * Data direction bit lookup
160 */
161static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
162 BLK_TC_ACT(BLK_TC_WRITE) };
163
164/* The ilog2() calls fall out because they're constant */
165#define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
166 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name))
167
168/*
169 * The worker for the various blk_add_trace*() types. Fills out a
170 * blk_io_trace structure and places it in a per-cpu subbuffer.
171 */
172static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
173 int rw, u32 what, int error, int pdu_len, void *pdu_data)
174{
175 struct task_struct *tsk = current;
176 struct ring_buffer_event *event = NULL;
177 struct blk_io_trace *t;
178 unsigned long flags = 0;
179 unsigned long *sequence;
180 pid_t pid;
181 int cpu, pc = 0;
182 bool blk_tracer = blk_tracer_enabled;
183
184 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
185 return;
186
187 what |= ddir_act[rw & WRITE];
188 what |= MASK_TC_BIT(rw, BARRIER);
189 what |= MASK_TC_BIT(rw, SYNCIO);
190 what |= MASK_TC_BIT(rw, AHEAD);
191 what |= MASK_TC_BIT(rw, META);
192 what |= MASK_TC_BIT(rw, DISCARD);
193
194 pid = tsk->pid;
195 if (unlikely(act_log_check(bt, what, sector, pid)))
196 return;
197 cpu = raw_smp_processor_id();
198
199 if (blk_tracer) {
200 tracing_record_cmdline(current);
201
202 pc = preempt_count();
203 event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
204 sizeof(*t) + pdu_len,
205 0, pc);
206 if (!event)
207 return;
208 t = ring_buffer_event_data(event);
209 goto record_it;
210 }
211
212 /*
213 * A word about the locking here - we disable interrupts to reserve
214 * some space in the relay per-cpu buffer, to prevent an irq
215 * from coming in and stepping on our toes.
216 */
217 local_irq_save(flags);
218
219 if (unlikely(tsk->btrace_seq != blktrace_seq))
220 trace_note_tsk(bt, tsk);
221
222 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
223 if (t) {
224 sequence = per_cpu_ptr(bt->sequence, cpu);
225
226 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
227 t->sequence = ++(*sequence);
228 t->time = ktime_to_ns(ktime_get());
229record_it:
230 /*
231 * These two are not needed in ftrace as they are in the
232 * generic trace_entry, filled by tracing_generic_entry_update,
233 * but for the trace_event->bin() synthesizer benefit we do it
234 * here too.
235 */
236 t->cpu = cpu;
237 t->pid = pid;
238
239 t->sector = sector;
240 t->bytes = bytes;
241 t->action = what;
242 t->device = bt->dev;
243 t->error = error;
244 t->pdu_len = pdu_len;
245
246 if (pdu_len)
247 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
248
249 if (blk_tracer) {
250 trace_buffer_unlock_commit(blk_tr, event, 0, pc);
251 return;
252 }
253 }
254
255 local_irq_restore(flags);
256}
257
258static struct dentry *blk_tree_root;
259static DEFINE_MUTEX(blk_tree_mutex);
260
261static void blk_trace_free(struct blk_trace *bt)
262{
263 debugfs_remove(bt->msg_file);
264 debugfs_remove(bt->dropped_file);
265 relay_close(bt->rchan);
266 free_percpu(bt->sequence);
267 free_percpu(bt->msg_data);
268 kfree(bt);
269}
270
271static void blk_trace_cleanup(struct blk_trace *bt)
272{
273 blk_trace_free(bt);
274 if (atomic_dec_and_test(&blk_probes_ref))
275 blk_unregister_tracepoints();
276}
277
278int blk_trace_remove(struct request_queue *q)
279{
280 struct blk_trace *bt;
281
282 bt = xchg(&q->blk_trace, NULL);
283 if (!bt)
284 return -EINVAL;
285
286 if (bt->trace_state != Blktrace_running)
287 blk_trace_cleanup(bt);
288
289 return 0;
290}
291EXPORT_SYMBOL_GPL(blk_trace_remove);
292
293static int blk_dropped_open(struct inode *inode, struct file *filp)
294{
295 filp->private_data = inode->i_private;
296
297 return 0;
298}
299
300static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
301 size_t count, loff_t *ppos)
302{
303 struct blk_trace *bt = filp->private_data;
304 char buf[16];
305
306 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
307
308 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
309}
310
311static const struct file_operations blk_dropped_fops = {
312 .owner = THIS_MODULE,
313 .open = blk_dropped_open,
314 .read = blk_dropped_read,
315};
316
317static int blk_msg_open(struct inode *inode, struct file *filp)
318{
319 filp->private_data = inode->i_private;
320
321 return 0;
322}
323
324static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
325 size_t count, loff_t *ppos)
326{
327 char *msg;
328 struct blk_trace *bt;
329
330 if (count >= BLK_TN_MAX_MSG)
331 return -EINVAL;
332
333 msg = kmalloc(count + 1, GFP_KERNEL);
334 if (msg == NULL)
335 return -ENOMEM;
336
337 if (copy_from_user(msg, buffer, count)) {
338 kfree(msg);
339 return -EFAULT;
340 }
341
342 msg[count] = '\0';
343 bt = filp->private_data;
344 __trace_note_message(bt, "%s", msg);
345 kfree(msg);
346
347 return count;
348}
349
350static const struct file_operations blk_msg_fops = {
351 .owner = THIS_MODULE,
352 .open = blk_msg_open,
353 .write = blk_msg_write,
354};
355
356/*
357 * Keep track of how many times we encountered a full subbuffer, to aid
358 * the user space app in telling how many lost events there were.
359 */
360static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
361 void *prev_subbuf, size_t prev_padding)
362{
363 struct blk_trace *bt;
364
365 if (!relay_buf_full(buf))
366 return 1;
367
368 bt = buf->chan->private_data;
369 atomic_inc(&bt->dropped);
370 return 0;
371}
372
373static int blk_remove_buf_file_callback(struct dentry *dentry)
374{
375 struct dentry *parent = dentry->d_parent;
376 debugfs_remove(dentry);
377
378 /*
379 * this will fail for all but the last file, but that is ok. what we
380 * care about is the top level buts->name directory going away, when
381 * the last trace file is gone. Then we don't have to rmdir() that
382 * manually on trace stop, so it nicely solves the issue with
383 * force killing of running traces.
384 */
385
386 debugfs_remove(parent);
387 return 0;
388}
389
390static struct dentry *blk_create_buf_file_callback(const char *filename,
391 struct dentry *parent,
392 int mode,
393 struct rchan_buf *buf,
394 int *is_global)
395{
396 return debugfs_create_file(filename, mode, parent, buf,
397 &relay_file_operations);
398}
399
400static struct rchan_callbacks blk_relay_callbacks = {
401 .subbuf_start = blk_subbuf_start_callback,
402 .create_buf_file = blk_create_buf_file_callback,
403 .remove_buf_file = blk_remove_buf_file_callback,
404};
405
406/*
407 * Setup everything required to start tracing
408 */
409int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
410 struct blk_user_trace_setup *buts)
411{
412 struct blk_trace *old_bt, *bt = NULL;
413 struct dentry *dir = NULL;
414 int ret, i;
415
416 if (!buts->buf_size || !buts->buf_nr)
417 return -EINVAL;
418
419 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
420 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
421
422 /*
423 * some device names have larger paths - convert the slashes
424 * to underscores for this to work as expected
425 */
426 for (i = 0; i < strlen(buts->name); i++)
427 if (buts->name[i] == '/')
428 buts->name[i] = '_';
429
430 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
431 if (!bt)
432 return -ENOMEM;
433
434 ret = -ENOMEM;
435 bt->sequence = alloc_percpu(unsigned long);
436 if (!bt->sequence)
437 goto err;
438
439 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
440 if (!bt->msg_data)
441 goto err;
442
443 ret = -ENOENT;
444
445 mutex_lock(&blk_tree_mutex);
446 if (!blk_tree_root) {
447 blk_tree_root = debugfs_create_dir("block", NULL);
448 if (!blk_tree_root) {
449 mutex_unlock(&blk_tree_mutex);
450 goto err;
451 }
452 }
453 mutex_unlock(&blk_tree_mutex);
454
455 dir = debugfs_create_dir(buts->name, blk_tree_root);
456
457 if (!dir)
458 goto err;
459
460 bt->dir = dir;
461 bt->dev = dev;
462 atomic_set(&bt->dropped, 0);
463
464 ret = -EIO;
465 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
466 &blk_dropped_fops);
467 if (!bt->dropped_file)
468 goto err;
469
470 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
471 if (!bt->msg_file)
472 goto err;
473
474 bt->rchan = relay_open("trace", dir, buts->buf_size,
475 buts->buf_nr, &blk_relay_callbacks, bt);
476 if (!bt->rchan)
477 goto err;
478
479 bt->act_mask = buts->act_mask;
480 if (!bt->act_mask)
481 bt->act_mask = (u16) -1;
482
483 bt->start_lba = buts->start_lba;
484 bt->end_lba = buts->end_lba;
485 if (!bt->end_lba)
486 bt->end_lba = -1ULL;
487
488 bt->pid = buts->pid;
489 bt->trace_state = Blktrace_setup;
490
491 ret = -EBUSY;
492 old_bt = xchg(&q->blk_trace, bt);
493 if (old_bt) {
494 (void) xchg(&q->blk_trace, old_bt);
495 goto err;
496 }
497
498 if (atomic_inc_return(&blk_probes_ref) == 1)
499 blk_register_tracepoints();
500
501 return 0;
502err:
503 blk_trace_free(bt);
504 return ret;
505}
506
507int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
508 char __user *arg)
509{
510 struct blk_user_trace_setup buts;
511 int ret;
512
513 ret = copy_from_user(&buts, arg, sizeof(buts));
514 if (ret)
515 return -EFAULT;
516
517 ret = do_blk_trace_setup(q, name, dev, &buts);
518 if (ret)
519 return ret;
520
521 if (copy_to_user(arg, &buts, sizeof(buts)))
522 return -EFAULT;
523
524 return 0;
525}
526EXPORT_SYMBOL_GPL(blk_trace_setup);
527
528int blk_trace_startstop(struct request_queue *q, int start)
529{
530 int ret;
531 struct blk_trace *bt = q->blk_trace;
532
533 if (bt == NULL)
534 return -EINVAL;
535
536 /*
537 * For starting a trace, we can transition from a setup or stopped
538 * trace. For stopping a trace, the state must be running
539 */
540 ret = -EINVAL;
541 if (start) {
542 if (bt->trace_state == Blktrace_setup ||
543 bt->trace_state == Blktrace_stopped) {
544 blktrace_seq++;
545 smp_mb();
546 bt->trace_state = Blktrace_running;
547
548 trace_note_time(bt);
549 ret = 0;
550 }
551 } else {
552 if (bt->trace_state == Blktrace_running) {
553 bt->trace_state = Blktrace_stopped;
554 relay_flush(bt->rchan);
555 ret = 0;
556 }
557 }
558
559 return ret;
560}
561EXPORT_SYMBOL_GPL(blk_trace_startstop);
562
563/**
564 * blk_trace_ioctl: - handle the ioctls associated with tracing
565 * @bdev: the block device
566 * @cmd: the ioctl cmd
567 * @arg: the argument data, if any
568 *
569 **/
570int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
571{
572 struct request_queue *q;
573 int ret, start = 0;
574 char b[BDEVNAME_SIZE];
575
576 q = bdev_get_queue(bdev);
577 if (!q)
578 return -ENXIO;
579
580 mutex_lock(&bdev->bd_mutex);
581
582 switch (cmd) {
583 case BLKTRACESETUP:
584 bdevname(bdev, b);
585 ret = blk_trace_setup(q, b, bdev->bd_dev, arg);
586 break;
587 case BLKTRACESTART:
588 start = 1;
589 case BLKTRACESTOP:
590 ret = blk_trace_startstop(q, start);
591 break;
592 case BLKTRACETEARDOWN:
593 ret = blk_trace_remove(q);
594 break;
595 default:
596 ret = -ENOTTY;
597 break;
598 }
599
600 mutex_unlock(&bdev->bd_mutex);
601 return ret;
602}
603
604/**
605 * blk_trace_shutdown: - stop and cleanup trace structures
606 * @q: the request queue associated with the device
607 *
608 **/
609void blk_trace_shutdown(struct request_queue *q)
610{
611 if (q->blk_trace) {
612 blk_trace_startstop(q, 0);
613 blk_trace_remove(q);
614 }
615}
616
617/*
618 * blktrace probes
619 */
620
621/**
622 * blk_add_trace_rq - Add a trace for a request oriented action
623 * @q: queue the io is for
624 * @rq: the source request
625 * @what: the action
626 *
627 * Description:
628 * Records an action against a request. Will log the bio offset + size.
629 *
630 **/
631static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
632 u32 what)
633{
634 struct blk_trace *bt = q->blk_trace;
635 int rw = rq->cmd_flags & 0x03;
636
637 if (likely(!bt))
638 return;
639
640 if (blk_discard_rq(rq))
641 rw |= (1 << BIO_RW_DISCARD);
642
643 if (blk_pc_request(rq)) {
644 what |= BLK_TC_ACT(BLK_TC_PC);
645 __blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors,
646 rq->cmd_len, rq->cmd);
647 } else {
648 what |= BLK_TC_ACT(BLK_TC_FS);
649 __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
650 rw, what, rq->errors, 0, NULL);
651 }
652}
653
654static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq)
655{
656 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
657}
658
659static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq)
660{
661 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
662}
663
664static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq)
665{
666 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
667}
668
669static void blk_add_trace_rq_requeue(struct request_queue *q,
670 struct request *rq)
671{
672 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
673}
674
675static void blk_add_trace_rq_complete(struct request_queue *q,
676 struct request *rq)
677{
678 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
679}
680
681/**
682 * blk_add_trace_bio - Add a trace for a bio oriented action
683 * @q: queue the io is for
684 * @bio: the source bio
685 * @what: the action
686 *
687 * Description:
688 * Records an action against a bio. Will log the bio offset + size.
689 *
690 **/
691static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
692 u32 what)
693{
694 struct blk_trace *bt = q->blk_trace;
695
696 if (likely(!bt))
697 return;
698
699 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
700 !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
701}
702
703static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio)
704{
705 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
706}
707
708static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio)
709{
710 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
711}
712
713static void blk_add_trace_bio_backmerge(struct request_queue *q,
714 struct bio *bio)
715{
716 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
717}
718
719static void blk_add_trace_bio_frontmerge(struct request_queue *q,
720 struct bio *bio)
721{
722 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
723}
724
725static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio)
726{
727 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
728}
729
730static void blk_add_trace_getrq(struct request_queue *q,
731 struct bio *bio, int rw)
732{
733 if (bio)
734 blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
735 else {
736 struct blk_trace *bt = q->blk_trace;
737
738 if (bt)
739 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
740 }
741}
742
743
744static void blk_add_trace_sleeprq(struct request_queue *q,
745 struct bio *bio, int rw)
746{
747 if (bio)
748 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
749 else {
750 struct blk_trace *bt = q->blk_trace;
751
752 if (bt)
753 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
754 0, 0, NULL);
755 }
756}
757
758static void blk_add_trace_plug(struct request_queue *q)
759{
760 struct blk_trace *bt = q->blk_trace;
761
762 if (bt)
763 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
764}
765
766static void blk_add_trace_unplug_io(struct request_queue *q)
767{
768 struct blk_trace *bt = q->blk_trace;
769
770 if (bt) {
771 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
772 __be64 rpdu = cpu_to_be64(pdu);
773
774 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
775 sizeof(rpdu), &rpdu);
776 }
777}
778
779static void blk_add_trace_unplug_timer(struct request_queue *q)
780{
781 struct blk_trace *bt = q->blk_trace;
782
783 if (bt) {
784 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
785 __be64 rpdu = cpu_to_be64(pdu);
786
787 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
788 sizeof(rpdu), &rpdu);
789 }
790}
791
792static void blk_add_trace_split(struct request_queue *q, struct bio *bio,
793 unsigned int pdu)
794{
795 struct blk_trace *bt = q->blk_trace;
796
797 if (bt) {
798 __be64 rpdu = cpu_to_be64(pdu);
799
800 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
801 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
802 sizeof(rpdu), &rpdu);
803 }
804}
805
806/**
807 * blk_add_trace_remap - Add a trace for a remap operation
808 * @q: queue the io is for
809 * @bio: the source bio
810 * @dev: target device
811 * @from: source sector
812 * @to: target sector
813 *
814 * Description:
815 * Device mapper or raid target sometimes need to split a bio because
816 * it spans a stripe (or similar). Add a trace for that action.
817 *
818 **/
819static void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
820 dev_t dev, sector_t from, sector_t to)
821{
822 struct blk_trace *bt = q->blk_trace;
823 struct blk_io_trace_remap r;
824
825 if (likely(!bt))
826 return;
827
828 r.device = cpu_to_be32(dev);
829 r.device_from = cpu_to_be32(bio->bi_bdev->bd_dev);
830 r.sector = cpu_to_be64(to);
831
832 __blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP,
833 !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
834}
835
836/**
837 * blk_add_driver_data - Add binary message with driver-specific data
838 * @q: queue the io is for
839 * @rq: io request
840 * @data: driver-specific data
841 * @len: length of driver-specific data
842 *
843 * Description:
844 * Some drivers might want to write driver-specific data per request.
845 *
846 **/
847void blk_add_driver_data(struct request_queue *q,
848 struct request *rq,
849 void *data, size_t len)
850{
851 struct blk_trace *bt = q->blk_trace;
852
853 if (likely(!bt))
854 return;
855
856 if (blk_pc_request(rq))
857 __blk_add_trace(bt, 0, rq->data_len, 0, BLK_TA_DRV_DATA,
858 rq->errors, len, data);
859 else
860 __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
861 0, BLK_TA_DRV_DATA, rq->errors, len, data);
862}
863EXPORT_SYMBOL_GPL(blk_add_driver_data);
864
865static void blk_register_tracepoints(void)
866{
867 int ret;
868
869 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort);
870 WARN_ON(ret);
871 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert);
872 WARN_ON(ret);
873 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue);
874 WARN_ON(ret);
875 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue);
876 WARN_ON(ret);
877 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete);
878 WARN_ON(ret);
879 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce);
880 WARN_ON(ret);
881 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete);
882 WARN_ON(ret);
883 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
884 WARN_ON(ret);
885 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
886 WARN_ON(ret);
887 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue);
888 WARN_ON(ret);
889 ret = register_trace_block_getrq(blk_add_trace_getrq);
890 WARN_ON(ret);
891 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq);
892 WARN_ON(ret);
893 ret = register_trace_block_plug(blk_add_trace_plug);
894 WARN_ON(ret);
895 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer);
896 WARN_ON(ret);
897 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io);
898 WARN_ON(ret);
899 ret = register_trace_block_split(blk_add_trace_split);
900 WARN_ON(ret);
901 ret = register_trace_block_remap(blk_add_trace_remap);
902 WARN_ON(ret);
903}
904
905static void blk_unregister_tracepoints(void)
906{
907 unregister_trace_block_remap(blk_add_trace_remap);
908 unregister_trace_block_split(blk_add_trace_split);
909 unregister_trace_block_unplug_io(blk_add_trace_unplug_io);
910 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer);
911 unregister_trace_block_plug(blk_add_trace_plug);
912 unregister_trace_block_sleeprq(blk_add_trace_sleeprq);
913 unregister_trace_block_getrq(blk_add_trace_getrq);
914 unregister_trace_block_bio_queue(blk_add_trace_bio_queue);
915 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
916 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
917 unregister_trace_block_bio_complete(blk_add_trace_bio_complete);
918 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce);
919 unregister_trace_block_rq_complete(blk_add_trace_rq_complete);
920 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue);
921 unregister_trace_block_rq_issue(blk_add_trace_rq_issue);
922 unregister_trace_block_rq_insert(blk_add_trace_rq_insert);
923 unregister_trace_block_rq_abort(blk_add_trace_rq_abort);
924
925 tracepoint_synchronize_unregister();
926}
927
928/*
929 * struct blk_io_tracer formatting routines
930 */
931
932static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
933{
934 int i = 0;
935 int tc = t->action >> BLK_TC_SHIFT;
936
937 if (t->action == BLK_TN_MESSAGE) {
938 rwbs[i++] = 'N';
939 goto out;
940 }
941
942 if (tc & BLK_TC_DISCARD)
943 rwbs[i++] = 'D';
944 else if (tc & BLK_TC_WRITE)
945 rwbs[i++] = 'W';
946 else if (t->bytes)
947 rwbs[i++] = 'R';
948 else
949 rwbs[i++] = 'N';
950
951 if (tc & BLK_TC_AHEAD)
952 rwbs[i++] = 'A';
953 if (tc & BLK_TC_BARRIER)
954 rwbs[i++] = 'B';
955 if (tc & BLK_TC_SYNC)
956 rwbs[i++] = 'S';
957 if (tc & BLK_TC_META)
958 rwbs[i++] = 'M';
959out:
960 rwbs[i] = '\0';
961}
962
963static inline
964const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
965{
966 return (const struct blk_io_trace *)ent;
967}
968
969static inline const void *pdu_start(const struct trace_entry *ent)
970{
971 return te_blk_io_trace(ent) + 1;
972}
973
974static inline u32 t_sec(const struct trace_entry *ent)
975{
976 return te_blk_io_trace(ent)->bytes >> 9;
977}
978
979static inline unsigned long long t_sector(const struct trace_entry *ent)
980{
981 return te_blk_io_trace(ent)->sector;
982}
983
984static inline __u16 t_error(const struct trace_entry *ent)
985{
986 return te_blk_io_trace(ent)->error;
987}
988
989static __u64 get_pdu_int(const struct trace_entry *ent)
990{
991 const __u64 *val = pdu_start(ent);
992 return be64_to_cpu(*val);
993}
994
995static void get_pdu_remap(const struct trace_entry *ent,
996 struct blk_io_trace_remap *r)
997{
998 const struct blk_io_trace_remap *__r = pdu_start(ent);
999 __u64 sector = __r->sector;
1000
1001 r->device = be32_to_cpu(__r->device);
1002 r->device_from = be32_to_cpu(__r->device_from);
1003 r->sector = be64_to_cpu(sector);
1004}
1005
1006typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1007
1008static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1009{
1010 char rwbs[6];
1011 unsigned long long ts = iter->ts;
1012 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1013 unsigned secs = (unsigned long)ts;
1014 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1015
1016 fill_rwbs(rwbs, t);
1017
1018 return trace_seq_printf(&iter->seq,
1019 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1020 MAJOR(t->device), MINOR(t->device), iter->cpu,
1021 secs, nsec_rem, iter->ent->pid, act, rwbs);
1022}
1023
1024static int blk_log_action(struct trace_iterator *iter, const char *act)
1025{
1026 char rwbs[6];
1027 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1028
1029 fill_rwbs(rwbs, t);
1030 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1031 MAJOR(t->device), MINOR(t->device), act, rwbs);
1032}
1033
1034static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1035{
1036 char cmd[TASK_COMM_LEN];
1037
1038 trace_find_cmdline(ent->pid, cmd);
1039
1040 if (t_sec(ent))
1041 return trace_seq_printf(s, "%llu + %u [%s]\n",
1042 t_sector(ent), t_sec(ent), cmd);
1043 return trace_seq_printf(s, "[%s]\n", cmd);
1044}
1045
1046static int blk_log_with_error(struct trace_seq *s,
1047 const struct trace_entry *ent)
1048{
1049 if (t_sec(ent))
1050 return trace_seq_printf(s, "%llu + %u [%d]\n", t_sector(ent),
1051 t_sec(ent), t_error(ent));
1052 return trace_seq_printf(s, "%llu [%d]\n", t_sector(ent), t_error(ent));
1053}
1054
1055static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1056{
1057 struct blk_io_trace_remap r = { .device = 0, };
1058
1059 get_pdu_remap(ent, &r);
1060 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1061 t_sector(ent),
1062 t_sec(ent), MAJOR(r.device), MINOR(r.device),
1063 (unsigned long long)r.sector);
1064}
1065
1066static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1067{
1068 char cmd[TASK_COMM_LEN];
1069
1070 trace_find_cmdline(ent->pid, cmd);
1071
1072 return trace_seq_printf(s, "[%s]\n", cmd);
1073}
1074
1075static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1076{
1077 char cmd[TASK_COMM_LEN];
1078
1079 trace_find_cmdline(ent->pid, cmd);
1080
1081 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1082}
1083
1084static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1085{
1086 char cmd[TASK_COMM_LEN];
1087
1088 trace_find_cmdline(ent->pid, cmd);
1089
1090 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1091 get_pdu_int(ent), cmd);
1092}
1093
1094static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1095{
1096 int ret;
1097 const struct blk_io_trace *t = te_blk_io_trace(ent);
1098
1099 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1100 if (ret)
1101 return trace_seq_putc(s, '\n');
1102 return ret;
1103}
1104
1105/*
1106 * struct tracer operations
1107 */
1108
1109static void blk_tracer_print_header(struct seq_file *m)
1110{
1111 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1112 return;
1113 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1114 "# | | | | | |\n");
1115}
1116
1117static void blk_tracer_start(struct trace_array *tr)
1118{
1119 blk_tracer_enabled = true;
1120 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1121}
1122
1123static int blk_tracer_init(struct trace_array *tr)
1124{
1125 blk_tr = tr;
1126 blk_tracer_start(tr);
1127 return 0;
1128}
1129
1130static void blk_tracer_stop(struct trace_array *tr)
1131{
1132 blk_tracer_enabled = false;
1133 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1134}
1135
1136static void blk_tracer_reset(struct trace_array *tr)
1137{
1138 blk_tracer_stop(tr);
1139}
1140
1141static const struct {
1142 const char *act[2];
1143 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1144} what2act[] = {
1145 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1146 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1147 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1148 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1149 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1150 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1151 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1152 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1153 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1154 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1155 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1156 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1157 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1158 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1159 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1160};
1161
1162static enum print_line_t print_one_line(struct trace_iterator *iter,
1163 bool classic)
1164{
1165 struct trace_seq *s = &iter->seq;
1166 const struct blk_io_trace *t;
1167 u16 what;
1168 int ret;
1169 bool long_act;
1170 blk_log_action_t *log_action;
1171
1172 t = te_blk_io_trace(iter->ent);
1173 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1174 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1175 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1176
1177 if (t->action == BLK_TN_MESSAGE) {
1178 ret = log_action(iter, long_act ? "message" : "m");
1179 if (ret)
1180 ret = blk_log_msg(s, iter->ent);
1181 goto out;
1182 }
1183
1184 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1185 ret = trace_seq_printf(s, "Bad pc action %x\n", what);
1186 else {
1187 ret = log_action(iter, what2act[what].act[long_act]);
1188 if (ret)
1189 ret = what2act[what].print(s, iter->ent);
1190 }
1191out:
1192 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1193}
1194
1195static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1196 int flags)
1197{
1198 if (!trace_print_context(iter))
1199 return TRACE_TYPE_PARTIAL_LINE;
1200
1201 return print_one_line(iter, false);
1202}
1203
1204static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1205{
1206 struct trace_seq *s = &iter->seq;
1207 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1208 const int offset = offsetof(struct blk_io_trace, sector);
1209 struct blk_io_trace old = {
1210 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1211 .time = iter->ts,
1212 };
1213
1214 if (!trace_seq_putmem(s, &old, offset))
1215 return 0;
1216 return trace_seq_putmem(s, &t->sector,
1217 sizeof(old) - offset + t->pdu_len);
1218}
1219
1220static enum print_line_t
1221blk_trace_event_print_binary(struct trace_iterator *iter, int flags)
1222{
1223 return blk_trace_synthesize_old_trace(iter) ?
1224 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1225}
1226
1227static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1228{
1229 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1230 return TRACE_TYPE_UNHANDLED;
1231
1232 return print_one_line(iter, true);
1233}
1234
1235static struct tracer blk_tracer __read_mostly = {
1236 .name = "blk",
1237 .init = blk_tracer_init,
1238 .reset = blk_tracer_reset,
1239 .start = blk_tracer_start,
1240 .stop = blk_tracer_stop,
1241 .print_header = blk_tracer_print_header,
1242 .print_line = blk_tracer_print_line,
1243 .flags = &blk_tracer_flags,
1244};
1245
1246static struct trace_event trace_blk_event = {
1247 .type = TRACE_BLK,
1248 .trace = blk_trace_event_print,
1249 .binary = blk_trace_event_print_binary,
1250};
1251
1252static int __init init_blk_tracer(void)
1253{
1254 if (!register_ftrace_event(&trace_blk_event)) {
1255 pr_warning("Warning: could not register block events\n");
1256 return 1;
1257 }
1258
1259 if (register_tracer(&blk_tracer) != 0) {
1260 pr_warning("Warning: could not register the block tracer\n");
1261 unregister_ftrace_event(&trace_blk_event);
1262 return 1;
1263 }
1264
1265 return 0;
1266}
1267
1268device_initcall(init_blk_tracer);
1269
1270static int blk_trace_remove_queue(struct request_queue *q)
1271{
1272 struct blk_trace *bt;
1273
1274 bt = xchg(&q->blk_trace, NULL);
1275 if (bt == NULL)
1276 return -EINVAL;
1277
1278 if (atomic_dec_and_test(&blk_probes_ref))
1279 blk_unregister_tracepoints();
1280
1281 blk_trace_free(bt);
1282 return 0;
1283}
1284
1285/*
1286 * Setup everything required to start tracing
1287 */
1288static int blk_trace_setup_queue(struct request_queue *q, dev_t dev)
1289{
1290 struct blk_trace *old_bt, *bt = NULL;
1291 int ret = -ENOMEM;
1292
1293 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1294 if (!bt)
1295 return -ENOMEM;
1296
1297 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1298 if (!bt->msg_data)
1299 goto free_bt;
1300
1301 bt->dev = dev;
1302 bt->act_mask = (u16)-1;
1303 bt->end_lba = -1ULL;
1304
1305 old_bt = xchg(&q->blk_trace, bt);
1306 if (old_bt != NULL) {
1307 (void)xchg(&q->blk_trace, old_bt);
1308 ret = -EBUSY;
1309 goto free_bt;
1310 }
1311
1312 if (atomic_inc_return(&blk_probes_ref) == 1)
1313 blk_register_tracepoints();
1314 return 0;
1315
1316free_bt:
1317 blk_trace_free(bt);
1318 return ret;
1319}
1320
1321/*
1322 * sysfs interface to enable and configure tracing
1323 */
1324
1325static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1326 struct device_attribute *attr,
1327 char *buf);
1328static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1329 struct device_attribute *attr,
1330 const char *buf, size_t count);
1331#define BLK_TRACE_DEVICE_ATTR(_name) \
1332 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1333 sysfs_blk_trace_attr_show, \
1334 sysfs_blk_trace_attr_store)
1335
1336static BLK_TRACE_DEVICE_ATTR(enable);
1337static BLK_TRACE_DEVICE_ATTR(act_mask);
1338static BLK_TRACE_DEVICE_ATTR(pid);
1339static BLK_TRACE_DEVICE_ATTR(start_lba);
1340static BLK_TRACE_DEVICE_ATTR(end_lba);
1341
1342static struct attribute *blk_trace_attrs[] = {
1343 &dev_attr_enable.attr,
1344 &dev_attr_act_mask.attr,
1345 &dev_attr_pid.attr,
1346 &dev_attr_start_lba.attr,
1347 &dev_attr_end_lba.attr,
1348 NULL
1349};
1350
1351struct attribute_group blk_trace_attr_group = {
1352 .name = "trace",
1353 .attrs = blk_trace_attrs,
1354};
1355
1356static const struct {
1357 int mask;
1358 const char *str;
1359} mask_maps[] = {
1360 { BLK_TC_READ, "read" },
1361 { BLK_TC_WRITE, "write" },
1362 { BLK_TC_BARRIER, "barrier" },
1363 { BLK_TC_SYNC, "sync" },
1364 { BLK_TC_QUEUE, "queue" },
1365 { BLK_TC_REQUEUE, "requeue" },
1366 { BLK_TC_ISSUE, "issue" },
1367 { BLK_TC_COMPLETE, "complete" },
1368 { BLK_TC_FS, "fs" },
1369 { BLK_TC_PC, "pc" },
1370 { BLK_TC_AHEAD, "ahead" },
1371 { BLK_TC_META, "meta" },
1372 { BLK_TC_DISCARD, "discard" },
1373 { BLK_TC_DRV_DATA, "drv_data" },
1374};
1375
1376static int blk_trace_str2mask(const char *str)
1377{
1378 int i;
1379 int mask = 0;
1380 char *s, *token;
1381
1382 s = kstrdup(str, GFP_KERNEL);
1383 if (s == NULL)
1384 return -ENOMEM;
1385 s = strstrip(s);
1386
1387 while (1) {
1388 token = strsep(&s, ",");
1389 if (token == NULL)
1390 break;
1391
1392 if (*token == '\0')
1393 continue;
1394
1395 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1396 if (strcasecmp(token, mask_maps[i].str) == 0) {
1397 mask |= mask_maps[i].mask;
1398 break;
1399 }
1400 }
1401 if (i == ARRAY_SIZE(mask_maps)) {
1402 mask = -EINVAL;
1403 break;
1404 }
1405 }
1406 kfree(s);
1407
1408 return mask;
1409}
1410
1411static ssize_t blk_trace_mask2str(char *buf, int mask)
1412{
1413 int i;
1414 char *p = buf;
1415
1416 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1417 if (mask & mask_maps[i].mask) {
1418 p += sprintf(p, "%s%s",
1419 (p == buf) ? "" : ",", mask_maps[i].str);
1420 }
1421 }
1422 *p++ = '\n';
1423
1424 return p - buf;
1425}
1426
1427static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1428{
1429 if (bdev->bd_disk == NULL)
1430 return NULL;
1431
1432 return bdev_get_queue(bdev);
1433}
1434
1435static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1436 struct device_attribute *attr,
1437 char *buf)
1438{
1439 struct hd_struct *p = dev_to_part(dev);
1440 struct request_queue *q;
1441 struct block_device *bdev;
1442 ssize_t ret = -ENXIO;
1443
1444 lock_kernel();
1445 bdev = bdget(part_devt(p));
1446 if (bdev == NULL)
1447 goto out_unlock_kernel;
1448
1449 q = blk_trace_get_queue(bdev);
1450 if (q == NULL)
1451 goto out_bdput;
1452
1453 mutex_lock(&bdev->bd_mutex);
1454
1455 if (attr == &dev_attr_enable) {
1456 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1457 goto out_unlock_bdev;
1458 }
1459
1460 if (q->blk_trace == NULL)
1461 ret = sprintf(buf, "disabled\n");
1462 else if (attr == &dev_attr_act_mask)
1463 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1464 else if (attr == &dev_attr_pid)
1465 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1466 else if (attr == &dev_attr_start_lba)
1467 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1468 else if (attr == &dev_attr_end_lba)
1469 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1470
1471out_unlock_bdev:
1472 mutex_unlock(&bdev->bd_mutex);
1473out_bdput:
1474 bdput(bdev);
1475out_unlock_kernel:
1476 unlock_kernel();
1477 return ret;
1478}
1479
1480static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1481 struct device_attribute *attr,
1482 const char *buf, size_t count)
1483{
1484 struct block_device *bdev;
1485 struct request_queue *q;
1486 struct hd_struct *p;
1487 u64 value;
1488 ssize_t ret = -EINVAL;
1489
1490 if (count == 0)
1491 goto out;
1492
1493 if (attr == &dev_attr_act_mask) {
1494 if (sscanf(buf, "%llx", &value) != 1) {
1495 /* Assume it is a list of trace category names */
1496 ret = blk_trace_str2mask(buf);
1497 if (ret < 0)
1498 goto out;
1499 value = ret;
1500 }
1501 } else if (sscanf(buf, "%llu", &value) != 1)
1502 goto out;
1503
1504 ret = -ENXIO;
1505
1506 lock_kernel();
1507 p = dev_to_part(dev);
1508 bdev = bdget(part_devt(p));
1509 if (bdev == NULL)
1510 goto out_unlock_kernel;
1511
1512 q = blk_trace_get_queue(bdev);
1513 if (q == NULL)
1514 goto out_bdput;
1515
1516 mutex_lock(&bdev->bd_mutex);
1517
1518 if (attr == &dev_attr_enable) {
1519 if (value)
1520 ret = blk_trace_setup_queue(q, bdev->bd_dev);
1521 else
1522 ret = blk_trace_remove_queue(q);
1523 goto out_unlock_bdev;
1524 }
1525
1526 ret = 0;
1527 if (q->blk_trace == NULL)
1528 ret = blk_trace_setup_queue(q, bdev->bd_dev);
1529
1530 if (ret == 0) {
1531 if (attr == &dev_attr_act_mask)
1532 q->blk_trace->act_mask = value;
1533 else if (attr == &dev_attr_pid)
1534 q->blk_trace->pid = value;
1535 else if (attr == &dev_attr_start_lba)
1536 q->blk_trace->start_lba = value;
1537 else if (attr == &dev_attr_end_lba)
1538 q->blk_trace->end_lba = value;
1539 }
1540
1541out_unlock_bdev:
1542 mutex_unlock(&bdev->bd_mutex);
1543out_bdput:
1544 bdput(bdev);
1545out_unlock_kernel:
1546 unlock_kernel();
1547out:
1548 return ret ? ret : count;
1549}
1550
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-13 22:29:04 -0500