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authorFrederic Weisbecker <fweisbec@gmail.com>2009-02-07 14:46:45 -0500
committerIngo Molnar <mingo@elte.hu>2009-02-09 04:51:02 -0500
commit2db270a80b8f2238e536876cfb3987af02684df8 (patch)
tree352bf63f9d48cf686a2a36c157707789a29fe7d1 /kernel/trace/blktrace.c
parent44b0635481437140b0e29d6023f05e805d5e7620 (diff)
tracing/blktrace: move the tracing file to kernel/trace
Impact: cleanup Move blktrace.c to kernel/trace, also move its config entry. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace/blktrace.c')
-rw-r--r--kernel/trace/blktrace.c1538
1 files changed, 1538 insertions, 0 deletions
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
new file mode 100644
index 000000000000..3b91da064820
--- /dev/null
+++ b/kernel/trace/blktrace.c
@@ -0,0 +1,1538 @@
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 int __read_mostly blk_tracer_enabled;
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 DEFINE_MUTEX(blk_probe_mutex);
51static atomic_t blk_probes_ref = ATOMIC_INIT(0);
52
53static int blk_register_tracepoints(void);
54static void blk_unregister_tracepoints(void);
55
56/*
57 * Send out a notify message.
58 */
59static void trace_note(struct blk_trace *bt, pid_t pid, int action,
60 const void *data, size_t len)
61{
62 struct blk_io_trace *t;
63
64 if (!bt->rchan)
65 return;
66
67 t = relay_reserve(bt->rchan, sizeof(*t) + len);
68 if (t) {
69 const int cpu = smp_processor_id();
70
71 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
72 t->time = ktime_to_ns(ktime_get());
73 t->device = bt->dev;
74 t->action = action;
75 t->pid = pid;
76 t->cpu = cpu;
77 t->pdu_len = len;
78 memcpy((void *) t + sizeof(*t), data, len);
79 }
80}
81
82/*
83 * Send out a notify for this process, if we haven't done so since a trace
84 * started
85 */
86static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
87{
88 tsk->btrace_seq = blktrace_seq;
89 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
90}
91
92static void trace_note_time(struct blk_trace *bt)
93{
94 struct timespec now;
95 unsigned long flags;
96 u32 words[2];
97
98 getnstimeofday(&now);
99 words[0] = now.tv_sec;
100 words[1] = now.tv_nsec;
101
102 local_irq_save(flags);
103 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
104 local_irq_restore(flags);
105}
106
107void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
108{
109 int n;
110 va_list args;
111 unsigned long flags;
112 char *buf;
113
114 if (blk_tr) {
115 va_start(args, fmt);
116 ftrace_vprintk(fmt, args);
117 va_end(args);
118 return;
119 }
120
121 if (!bt->msg_data)
122 return;
123
124 local_irq_save(flags);
125 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
126 va_start(args, fmt);
127 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
128 va_end(args);
129
130 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
131 local_irq_restore(flags);
132}
133EXPORT_SYMBOL_GPL(__trace_note_message);
134
135static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
136 pid_t pid)
137{
138 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
139 return 1;
140 if (sector < bt->start_lba || sector > bt->end_lba)
141 return 1;
142 if (bt->pid && pid != bt->pid)
143 return 1;
144
145 return 0;
146}
147
148/*
149 * Data direction bit lookup
150 */
151static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ),
152 BLK_TC_ACT(BLK_TC_WRITE) };
153
154/* The ilog2() calls fall out because they're constant */
155#define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
156 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name))
157
158/*
159 * The worker for the various blk_add_trace*() types. Fills out a
160 * blk_io_trace structure and places it in a per-cpu subbuffer.
161 */
162static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
163 int rw, u32 what, int error, int pdu_len, void *pdu_data)
164{
165 struct task_struct *tsk = current;
166 struct ring_buffer_event *event = NULL;
167 struct blk_io_trace *t;
168 unsigned long flags = 0;
169 unsigned long *sequence;
170 pid_t pid;
171 int cpu, pc = 0;
172
173 if (unlikely(bt->trace_state != Blktrace_running ||
174 !blk_tracer_enabled))
175 return;
176
177 what |= ddir_act[rw & WRITE];
178 what |= MASK_TC_BIT(rw, BARRIER);
179 what |= MASK_TC_BIT(rw, SYNC);
180 what |= MASK_TC_BIT(rw, AHEAD);
181 what |= MASK_TC_BIT(rw, META);
182 what |= MASK_TC_BIT(rw, DISCARD);
183
184 pid = tsk->pid;
185 if (unlikely(act_log_check(bt, what, sector, pid)))
186 return;
187 cpu = raw_smp_processor_id();
188
189 if (blk_tr) {
190 tracing_record_cmdline(current);
191
192 pc = preempt_count();
193 event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
194 sizeof(*t) + pdu_len,
195 0, pc);
196 if (!event)
197 return;
198 t = ring_buffer_event_data(event);
199 goto record_it;
200 }
201
202 /*
203 * A word about the locking here - we disable interrupts to reserve
204 * some space in the relay per-cpu buffer, to prevent an irq
205 * from coming in and stepping on our toes.
206 */
207 local_irq_save(flags);
208
209 if (unlikely(tsk->btrace_seq != blktrace_seq))
210 trace_note_tsk(bt, tsk);
211
212 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
213 if (t) {
214 sequence = per_cpu_ptr(bt->sequence, cpu);
215
216 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
217 t->sequence = ++(*sequence);
218 t->time = ktime_to_ns(ktime_get());
219record_it:
220 /*
221 * These two are not needed in ftrace as they are in the
222 * generic trace_entry, filled by tracing_generic_entry_update,
223 * but for the trace_event->bin() synthesizer benefit we do it
224 * here too.
225 */
226 t->cpu = cpu;
227 t->pid = pid;
228
229 t->sector = sector;
230 t->bytes = bytes;
231 t->action = what;
232 t->device = bt->dev;
233 t->error = error;
234 t->pdu_len = pdu_len;
235
236 if (pdu_len)
237 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
238
239 if (blk_tr) {
240 trace_buffer_unlock_commit(blk_tr, event, 0, pc);
241 return;
242 }
243 }
244
245 local_irq_restore(flags);
246}
247
248static struct dentry *blk_tree_root;
249static DEFINE_MUTEX(blk_tree_mutex);
250
251static void blk_trace_cleanup(struct blk_trace *bt)
252{
253 debugfs_remove(bt->msg_file);
254 debugfs_remove(bt->dropped_file);
255 relay_close(bt->rchan);
256 free_percpu(bt->sequence);
257 free_percpu(bt->msg_data);
258 kfree(bt);
259 mutex_lock(&blk_probe_mutex);
260 if (atomic_dec_and_test(&blk_probes_ref))
261 blk_unregister_tracepoints();
262 mutex_unlock(&blk_probe_mutex);
263}
264
265int blk_trace_remove(struct request_queue *q)
266{
267 struct blk_trace *bt;
268
269 bt = xchg(&q->blk_trace, NULL);
270 if (!bt)
271 return -EINVAL;
272
273 if (bt->trace_state == Blktrace_setup ||
274 bt->trace_state == Blktrace_stopped)
275 blk_trace_cleanup(bt);
276
277 return 0;
278}
279EXPORT_SYMBOL_GPL(blk_trace_remove);
280
281static int blk_dropped_open(struct inode *inode, struct file *filp)
282{
283 filp->private_data = inode->i_private;
284
285 return 0;
286}
287
288static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
289 size_t count, loff_t *ppos)
290{
291 struct blk_trace *bt = filp->private_data;
292 char buf[16];
293
294 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
295
296 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
297}
298
299static const struct file_operations blk_dropped_fops = {
300 .owner = THIS_MODULE,
301 .open = blk_dropped_open,
302 .read = blk_dropped_read,
303};
304
305static int blk_msg_open(struct inode *inode, struct file *filp)
306{
307 filp->private_data = inode->i_private;
308
309 return 0;
310}
311
312static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
313 size_t count, loff_t *ppos)
314{
315 char *msg;
316 struct blk_trace *bt;
317
318 if (count > BLK_TN_MAX_MSG)
319 return -EINVAL;
320
321 msg = kmalloc(count, GFP_KERNEL);
322 if (msg == NULL)
323 return -ENOMEM;
324
325 if (copy_from_user(msg, buffer, count)) {
326 kfree(msg);
327 return -EFAULT;
328 }
329
330 bt = filp->private_data;
331 __trace_note_message(bt, "%s", msg);
332 kfree(msg);
333
334 return count;
335}
336
337static const struct file_operations blk_msg_fops = {
338 .owner = THIS_MODULE,
339 .open = blk_msg_open,
340 .write = blk_msg_write,
341};
342
343/*
344 * Keep track of how many times we encountered a full subbuffer, to aid
345 * the user space app in telling how many lost events there were.
346 */
347static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
348 void *prev_subbuf, size_t prev_padding)
349{
350 struct blk_trace *bt;
351
352 if (!relay_buf_full(buf))
353 return 1;
354
355 bt = buf->chan->private_data;
356 atomic_inc(&bt->dropped);
357 return 0;
358}
359
360static int blk_remove_buf_file_callback(struct dentry *dentry)
361{
362 struct dentry *parent = dentry->d_parent;
363 debugfs_remove(dentry);
364
365 /*
366 * this will fail for all but the last file, but that is ok. what we
367 * care about is the top level buts->name directory going away, when
368 * the last trace file is gone. Then we don't have to rmdir() that
369 * manually on trace stop, so it nicely solves the issue with
370 * force killing of running traces.
371 */
372
373 debugfs_remove(parent);
374 return 0;
375}
376
377static struct dentry *blk_create_buf_file_callback(const char *filename,
378 struct dentry *parent,
379 int mode,
380 struct rchan_buf *buf,
381 int *is_global)
382{
383 return debugfs_create_file(filename, mode, parent, buf,
384 &relay_file_operations);
385}
386
387static struct rchan_callbacks blk_relay_callbacks = {
388 .subbuf_start = blk_subbuf_start_callback,
389 .create_buf_file = blk_create_buf_file_callback,
390 .remove_buf_file = blk_remove_buf_file_callback,
391};
392
393/*
394 * Setup everything required to start tracing
395 */
396int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
397 struct blk_user_trace_setup *buts)
398{
399 struct blk_trace *old_bt, *bt = NULL;
400 struct dentry *dir = NULL;
401 int ret, i;
402
403 if (!buts->buf_size || !buts->buf_nr)
404 return -EINVAL;
405
406 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
407 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
408
409 /*
410 * some device names have larger paths - convert the slashes
411 * to underscores for this to work as expected
412 */
413 for (i = 0; i < strlen(buts->name); i++)
414 if (buts->name[i] == '/')
415 buts->name[i] = '_';
416
417 ret = -ENOMEM;
418 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
419 if (!bt)
420 goto err;
421
422 bt->sequence = alloc_percpu(unsigned long);
423 if (!bt->sequence)
424 goto err;
425
426 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG);
427 if (!bt->msg_data)
428 goto err;
429
430 ret = -ENOENT;
431
432 if (!blk_tree_root) {
433 blk_tree_root = debugfs_create_dir("block", NULL);
434 if (!blk_tree_root)
435 return -ENOMEM;
436 }
437
438 dir = debugfs_create_dir(buts->name, blk_tree_root);
439
440 if (!dir)
441 goto err;
442
443 bt->dir = dir;
444 bt->dev = dev;
445 atomic_set(&bt->dropped, 0);
446
447 ret = -EIO;
448 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
449 &blk_dropped_fops);
450 if (!bt->dropped_file)
451 goto err;
452
453 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
454 if (!bt->msg_file)
455 goto err;
456
457 bt->rchan = relay_open("trace", dir, buts->buf_size,
458 buts->buf_nr, &blk_relay_callbacks, bt);
459 if (!bt->rchan)
460 goto err;
461
462 bt->act_mask = buts->act_mask;
463 if (!bt->act_mask)
464 bt->act_mask = (u16) -1;
465
466 bt->start_lba = buts->start_lba;
467 bt->end_lba = buts->end_lba;
468 if (!bt->end_lba)
469 bt->end_lba = -1ULL;
470
471 bt->pid = buts->pid;
472 bt->trace_state = Blktrace_setup;
473
474 mutex_lock(&blk_probe_mutex);
475 if (atomic_add_return(1, &blk_probes_ref) == 1) {
476 ret = blk_register_tracepoints();
477 if (ret)
478 goto probe_err;
479 }
480 mutex_unlock(&blk_probe_mutex);
481
482 ret = -EBUSY;
483 old_bt = xchg(&q->blk_trace, bt);
484 if (old_bt) {
485 (void) xchg(&q->blk_trace, old_bt);
486 goto err;
487 }
488
489 return 0;
490probe_err:
491 atomic_dec(&blk_probes_ref);
492 mutex_unlock(&blk_probe_mutex);
493err:
494 if (bt) {
495 if (bt->msg_file)
496 debugfs_remove(bt->msg_file);
497 if (bt->dropped_file)
498 debugfs_remove(bt->dropped_file);
499 free_percpu(bt->sequence);
500 free_percpu(bt->msg_data);
501 if (bt->rchan)
502 relay_close(bt->rchan);
503 kfree(bt);
504 }
505 return ret;
506}
507
508int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
509 char __user *arg)
510{
511 struct blk_user_trace_setup buts;
512 int ret;
513
514 ret = copy_from_user(&buts, arg, sizeof(buts));
515 if (ret)
516 return -EFAULT;
517
518 ret = do_blk_trace_setup(q, name, dev, &buts);
519 if (ret)
520 return ret;
521
522 if (copy_to_user(arg, &buts, sizeof(buts)))
523 return -EFAULT;
524
525 return 0;
526}
527EXPORT_SYMBOL_GPL(blk_trace_setup);
528
529int blk_trace_startstop(struct request_queue *q, int start)
530{
531 int ret;
532 struct blk_trace *bt = q->blk_trace;
533
534 if (bt == NULL)
535 return -EINVAL;
536
537 /*
538 * For starting a trace, we can transition from a setup or stopped
539 * trace. For stopping a trace, the state must be running
540 */
541 ret = -EINVAL;
542 if (start) {
543 if (bt->trace_state == Blktrace_setup ||
544 bt->trace_state == Blktrace_stopped) {
545 blktrace_seq++;
546 smp_mb();
547 bt->trace_state = Blktrace_running;
548
549 trace_note_time(bt);
550 ret = 0;
551 }
552 } else {
553 if (bt->trace_state == Blktrace_running) {
554 bt->trace_state = Blktrace_stopped;
555 relay_flush(bt->rchan);
556 ret = 0;
557 }
558 }
559
560 return ret;
561}
562EXPORT_SYMBOL_GPL(blk_trace_startstop);
563
564/**
565 * blk_trace_ioctl: - handle the ioctls associated with tracing
566 * @bdev: the block device
567 * @cmd: the ioctl cmd
568 * @arg: the argument data, if any
569 *
570 **/
571int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
572{
573 struct request_queue *q;
574 int ret, start = 0;
575 char b[BDEVNAME_SIZE];
576
577 q = bdev_get_queue(bdev);
578 if (!q)
579 return -ENXIO;
580
581 mutex_lock(&bdev->bd_mutex);
582
583 switch (cmd) {
584 case BLKTRACESETUP:
585 bdevname(bdev, b);
586 ret = blk_trace_setup(q, b, bdev->bd_dev, arg);
587 break;
588 case BLKTRACESTART:
589 start = 1;
590 case BLKTRACESTOP:
591 ret = blk_trace_startstop(q, start);
592 break;
593 case BLKTRACETEARDOWN:
594 ret = blk_trace_remove(q);
595 break;
596 default:
597 ret = -ENOTTY;
598 break;
599 }
600
601 mutex_unlock(&bdev->bd_mutex);
602 return ret;
603}
604
605/**
606 * blk_trace_shutdown: - stop and cleanup trace structures
607 * @q: the request queue associated with the device
608 *
609 **/
610void blk_trace_shutdown(struct request_queue *q)
611{
612 if (q->blk_trace) {
613 blk_trace_startstop(q, 0);
614 blk_trace_remove(q);
615 }
616}
617
618/*
619 * blktrace probes
620 */
621
622/**
623 * blk_add_trace_rq - Add a trace for a request oriented action
624 * @q: queue the io is for
625 * @rq: the source request
626 * @what: the action
627 *
628 * Description:
629 * Records an action against a request. Will log the bio offset + size.
630 *
631 **/
632static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
633 u32 what)
634{
635 struct blk_trace *bt = q->blk_trace;
636 int rw = rq->cmd_flags & 0x03;
637
638 if (likely(!bt))
639 return;
640
641 if (blk_discard_rq(rq))
642 rw |= (1 << BIO_RW_DISCARD);
643
644 if (blk_pc_request(rq)) {
645 what |= BLK_TC_ACT(BLK_TC_PC);
646 __blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors,
647 sizeof(rq->cmd), rq->cmd);
648 } else {
649 what |= BLK_TC_ACT(BLK_TC_FS);
650 __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
651 rw, what, rq->errors, 0, NULL);
652 }
653}
654
655static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq)
656{
657 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
658}
659
660static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq)
661{
662 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
663}
664
665static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq)
666{
667 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
668}
669
670static void blk_add_trace_rq_requeue(struct request_queue *q,
671 struct request *rq)
672{
673 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
674}
675
676static void blk_add_trace_rq_complete(struct request_queue *q,
677 struct request *rq)
678{
679 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
680}
681
682/**
683 * blk_add_trace_bio - Add a trace for a bio oriented action
684 * @q: queue the io is for
685 * @bio: the source bio
686 * @what: the action
687 *
688 * Description:
689 * Records an action against a bio. Will log the bio offset + size.
690 *
691 **/
692static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
693 u32 what)
694{
695 struct blk_trace *bt = q->blk_trace;
696
697 if (likely(!bt))
698 return;
699
700 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
701 !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
702}
703
704static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio)
705{
706 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
707}
708
709static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio)
710{
711 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
712}
713
714static void blk_add_trace_bio_backmerge(struct request_queue *q,
715 struct bio *bio)
716{
717 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
718}
719
720static void blk_add_trace_bio_frontmerge(struct request_queue *q,
721 struct bio *bio)
722{
723 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
724}
725
726static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio)
727{
728 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
729}
730
731static void blk_add_trace_getrq(struct request_queue *q,
732 struct bio *bio, int rw)
733{
734 if (bio)
735 blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
736 else {
737 struct blk_trace *bt = q->blk_trace;
738
739 if (bt)
740 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
741 }
742}
743
744
745static void blk_add_trace_sleeprq(struct request_queue *q,
746 struct bio *bio, int rw)
747{
748 if (bio)
749 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
750 else {
751 struct blk_trace *bt = q->blk_trace;
752
753 if (bt)
754 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
755 0, 0, NULL);
756 }
757}
758
759static void blk_add_trace_plug(struct request_queue *q)
760{
761 struct blk_trace *bt = q->blk_trace;
762
763 if (bt)
764 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
765}
766
767static void blk_add_trace_unplug_io(struct request_queue *q)
768{
769 struct blk_trace *bt = q->blk_trace;
770
771 if (bt) {
772 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
773 __be64 rpdu = cpu_to_be64(pdu);
774
775 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
776 sizeof(rpdu), &rpdu);
777 }
778}
779
780static void blk_add_trace_unplug_timer(struct request_queue *q)
781{
782 struct blk_trace *bt = q->blk_trace;
783
784 if (bt) {
785 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
786 __be64 rpdu = cpu_to_be64(pdu);
787
788 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
789 sizeof(rpdu), &rpdu);
790 }
791}
792
793static void blk_add_trace_split(struct request_queue *q, struct bio *bio,
794 unsigned int pdu)
795{
796 struct blk_trace *bt = q->blk_trace;
797
798 if (bt) {
799 __be64 rpdu = cpu_to_be64(pdu);
800
801 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
802 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
803 sizeof(rpdu), &rpdu);
804 }
805}
806
807/**
808 * blk_add_trace_remap - Add a trace for a remap operation
809 * @q: queue the io is for
810 * @bio: the source bio
811 * @dev: target device
812 * @from: source sector
813 * @to: target sector
814 *
815 * Description:
816 * Device mapper or raid target sometimes need to split a bio because
817 * it spans a stripe (or similar). Add a trace for that action.
818 *
819 **/
820static void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
821 dev_t dev, sector_t from, sector_t to)
822{
823 struct blk_trace *bt = q->blk_trace;
824 struct blk_io_trace_remap r;
825
826 if (likely(!bt))
827 return;
828
829 r.device = cpu_to_be32(dev);
830 r.device_from = cpu_to_be32(bio->bi_bdev->bd_dev);
831 r.sector = cpu_to_be64(to);
832
833 __blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP,
834 !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
835}
836
837/**
838 * blk_add_driver_data - Add binary message with driver-specific data
839 * @q: queue the io is for
840 * @rq: io request
841 * @data: driver-specific data
842 * @len: length of driver-specific data
843 *
844 * Description:
845 * Some drivers might want to write driver-specific data per request.
846 *
847 **/
848void blk_add_driver_data(struct request_queue *q,
849 struct request *rq,
850 void *data, size_t len)
851{
852 struct blk_trace *bt = q->blk_trace;
853
854 if (likely(!bt))
855 return;
856
857 if (blk_pc_request(rq))
858 __blk_add_trace(bt, 0, rq->data_len, 0, BLK_TA_DRV_DATA,
859 rq->errors, len, data);
860 else
861 __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
862 0, BLK_TA_DRV_DATA, rq->errors, len, data);
863}
864EXPORT_SYMBOL_GPL(blk_add_driver_data);
865
866static int blk_register_tracepoints(void)
867{
868 int ret;
869
870 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort);
871 WARN_ON(ret);
872 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert);
873 WARN_ON(ret);
874 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue);
875 WARN_ON(ret);
876 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue);
877 WARN_ON(ret);
878 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete);
879 WARN_ON(ret);
880 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce);
881 WARN_ON(ret);
882 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete);
883 WARN_ON(ret);
884 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
885 WARN_ON(ret);
886 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
887 WARN_ON(ret);
888 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue);
889 WARN_ON(ret);
890 ret = register_trace_block_getrq(blk_add_trace_getrq);
891 WARN_ON(ret);
892 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq);
893 WARN_ON(ret);
894 ret = register_trace_block_plug(blk_add_trace_plug);
895 WARN_ON(ret);
896 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer);
897 WARN_ON(ret);
898 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io);
899 WARN_ON(ret);
900 ret = register_trace_block_split(blk_add_trace_split);
901 WARN_ON(ret);
902 ret = register_trace_block_remap(blk_add_trace_remap);
903 WARN_ON(ret);
904 return 0;
905}
906
907static void blk_unregister_tracepoints(void)
908{
909 unregister_trace_block_remap(blk_add_trace_remap);
910 unregister_trace_block_split(blk_add_trace_split);
911 unregister_trace_block_unplug_io(blk_add_trace_unplug_io);
912 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer);
913 unregister_trace_block_plug(blk_add_trace_plug);
914 unregister_trace_block_sleeprq(blk_add_trace_sleeprq);
915 unregister_trace_block_getrq(blk_add_trace_getrq);
916 unregister_trace_block_bio_queue(blk_add_trace_bio_queue);
917 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
918 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
919 unregister_trace_block_bio_complete(blk_add_trace_bio_complete);
920 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce);
921 unregister_trace_block_rq_complete(blk_add_trace_rq_complete);
922 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue);
923 unregister_trace_block_rq_issue(blk_add_trace_rq_issue);
924 unregister_trace_block_rq_insert(blk_add_trace_rq_insert);
925 unregister_trace_block_rq_abort(blk_add_trace_rq_abort);
926
927 tracepoint_synchronize_unregister();
928}
929
930/*
931 * struct blk_io_tracer formatting routines
932 */
933
934static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
935{
936 int i = 0;
937
938 if (t->action & BLK_TC_DISCARD)
939 rwbs[i++] = 'D';
940 else if (t->action & BLK_TC_WRITE)
941 rwbs[i++] = 'W';
942 else if (t->bytes)
943 rwbs[i++] = 'R';
944 else
945 rwbs[i++] = 'N';
946
947 if (t->action & BLK_TC_AHEAD)
948 rwbs[i++] = 'A';
949 if (t->action & BLK_TC_BARRIER)
950 rwbs[i++] = 'B';
951 if (t->action & BLK_TC_SYNC)
952 rwbs[i++] = 'S';
953 if (t->action & BLK_TC_META)
954 rwbs[i++] = 'M';
955
956 rwbs[i] = '\0';
957}
958
959static inline
960const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
961{
962 return (const struct blk_io_trace *)ent;
963}
964
965static inline const void *pdu_start(const struct trace_entry *ent)
966{
967 return te_blk_io_trace(ent) + 1;
968}
969
970static inline u32 t_sec(const struct trace_entry *ent)
971{
972 return te_blk_io_trace(ent)->bytes >> 9;
973}
974
975static inline unsigned long long t_sector(const struct trace_entry *ent)
976{
977 return te_blk_io_trace(ent)->sector;
978}
979
980static inline __u16 t_error(const struct trace_entry *ent)
981{
982 return te_blk_io_trace(ent)->sector;
983}
984
985static __u64 get_pdu_int(const struct trace_entry *ent)
986{
987 const __u64 *val = pdu_start(ent);
988 return be64_to_cpu(*val);
989}
990
991static void get_pdu_remap(const struct trace_entry *ent,
992 struct blk_io_trace_remap *r)
993{
994 const struct blk_io_trace_remap *__r = pdu_start(ent);
995 __u64 sector = __r->sector;
996
997 r->device = be32_to_cpu(__r->device);
998 r->device_from = be32_to_cpu(__r->device_from);
999 r->sector = be64_to_cpu(sector);
1000}
1001
1002static int blk_log_action_iter(struct trace_iterator *iter, const char *act)
1003{
1004 char rwbs[6];
1005 unsigned long long ts = ns2usecs(iter->ts);
1006 unsigned long usec_rem = do_div(ts, USEC_PER_SEC);
1007 unsigned secs = (unsigned long)ts;
1008 const struct trace_entry *ent = iter->ent;
1009 const struct blk_io_trace *t = (const struct blk_io_trace *)ent;
1010
1011 fill_rwbs(rwbs, t);
1012
1013 return trace_seq_printf(&iter->seq,
1014 "%3d,%-3d %2d %5d.%06lu %5u %2s %3s ",
1015 MAJOR(t->device), MINOR(t->device), iter->cpu,
1016 secs, usec_rem, ent->pid, act, rwbs);
1017}
1018
1019static int blk_log_action_seq(struct trace_seq *s, const struct blk_io_trace *t,
1020 const char *act)
1021{
1022 char rwbs[6];
1023 fill_rwbs(rwbs, t);
1024 return trace_seq_printf(s, "%3d,%-3d %2s %3s ",
1025 MAJOR(t->device), MINOR(t->device), act, rwbs);
1026}
1027
1028static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1029{
1030 const char *cmd = trace_find_cmdline(ent->pid);
1031
1032 if (t_sec(ent))
1033 return trace_seq_printf(s, "%llu + %u [%s]\n",
1034 t_sector(ent), t_sec(ent), cmd);
1035 return trace_seq_printf(s, "[%s]\n", cmd);
1036}
1037
1038static int blk_log_with_error(struct trace_seq *s,
1039 const struct trace_entry *ent)
1040{
1041 if (t_sec(ent))
1042 return trace_seq_printf(s, "%llu + %u [%d]\n", t_sector(ent),
1043 t_sec(ent), t_error(ent));
1044 return trace_seq_printf(s, "%llu [%d]\n", t_sector(ent), t_error(ent));
1045}
1046
1047static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1048{
1049 struct blk_io_trace_remap r = { .device = 0, };
1050
1051 get_pdu_remap(ent, &r);
1052 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1053 t_sector(ent),
1054 t_sec(ent), MAJOR(r.device), MINOR(r.device),
1055 (unsigned long long)r.sector);
1056}
1057
1058static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1059{
1060 return trace_seq_printf(s, "[%s]\n", trace_find_cmdline(ent->pid));
1061}
1062
1063static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1064{
1065 return trace_seq_printf(s, "[%s] %llu\n", trace_find_cmdline(ent->pid),
1066 get_pdu_int(ent));
1067}
1068
1069static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1070{
1071 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1072 get_pdu_int(ent), trace_find_cmdline(ent->pid));
1073}
1074
1075/*
1076 * struct tracer operations
1077 */
1078
1079static void blk_tracer_print_header(struct seq_file *m)
1080{
1081 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1082 return;
1083 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1084 "# | | | | | |\n");
1085}
1086
1087static void blk_tracer_start(struct trace_array *tr)
1088{
1089 mutex_lock(&blk_probe_mutex);
1090 if (atomic_add_return(1, &blk_probes_ref) == 1)
1091 if (blk_register_tracepoints())
1092 atomic_dec(&blk_probes_ref);
1093 mutex_unlock(&blk_probe_mutex);
1094 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1095}
1096
1097static int blk_tracer_init(struct trace_array *tr)
1098{
1099 blk_tr = tr;
1100 blk_tracer_start(tr);
1101 mutex_lock(&blk_probe_mutex);
1102 blk_tracer_enabled++;
1103 mutex_unlock(&blk_probe_mutex);
1104 return 0;
1105}
1106
1107static void blk_tracer_stop(struct trace_array *tr)
1108{
1109 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1110 mutex_lock(&blk_probe_mutex);
1111 if (atomic_dec_and_test(&blk_probes_ref))
1112 blk_unregister_tracepoints();
1113 mutex_unlock(&blk_probe_mutex);
1114}
1115
1116static void blk_tracer_reset(struct trace_array *tr)
1117{
1118 if (!atomic_read(&blk_probes_ref))
1119 return;
1120
1121 mutex_lock(&blk_probe_mutex);
1122 blk_tracer_enabled--;
1123 WARN_ON(blk_tracer_enabled < 0);
1124 mutex_unlock(&blk_probe_mutex);
1125
1126 blk_tracer_stop(tr);
1127}
1128
1129static struct {
1130 const char *act[2];
1131 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1132} what2act[] __read_mostly = {
1133 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1134 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1135 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1136 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1137 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1138 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1139 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1140 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1141 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1142 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1143 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1144 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1145 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1146 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1147 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1148};
1149
1150static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1151 int flags)
1152{
1153 struct trace_seq *s = &iter->seq;
1154 const struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1155 const u16 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1156 int ret;
1157
1158 if (!trace_print_context(iter))
1159 return TRACE_TYPE_PARTIAL_LINE;
1160
1161 if (unlikely(what == 0 || what > ARRAY_SIZE(what2act)))
1162 ret = trace_seq_printf(s, "Bad pc action %x\n", what);
1163 else {
1164 const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1165 ret = blk_log_action_seq(s, t, what2act[what].act[long_act]);
1166 if (ret)
1167 ret = what2act[what].print(s, iter->ent);
1168 }
1169
1170 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1171}
1172
1173static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1174{
1175 struct trace_seq *s = &iter->seq;
1176 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1177 const int offset = offsetof(struct blk_io_trace, sector);
1178 struct blk_io_trace old = {
1179 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1180 .time = ns2usecs(iter->ts),
1181 };
1182
1183 if (!trace_seq_putmem(s, &old, offset))
1184 return 0;
1185 return trace_seq_putmem(s, &t->sector,
1186 sizeof(old) - offset + t->pdu_len);
1187}
1188
1189static enum print_line_t
1190blk_trace_event_print_binary(struct trace_iterator *iter, int flags)
1191{
1192 return blk_trace_synthesize_old_trace(iter) ?
1193 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1194}
1195
1196static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1197{
1198 const struct blk_io_trace *t;
1199 u16 what;
1200 int ret;
1201
1202 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1203 return TRACE_TYPE_UNHANDLED;
1204
1205 t = (const struct blk_io_trace *)iter->ent;
1206 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1207
1208 if (unlikely(what == 0 || what > ARRAY_SIZE(what2act)))
1209 ret = trace_seq_printf(&iter->seq, "Bad pc action %x\n", what);
1210 else {
1211 const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1212 ret = blk_log_action_iter(iter, what2act[what].act[long_act]);
1213 if (ret)
1214 ret = what2act[what].print(&iter->seq, iter->ent);
1215 }
1216
1217 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1218}
1219
1220static struct tracer blk_tracer __read_mostly = {
1221 .name = "blk",
1222 .init = blk_tracer_init,
1223 .reset = blk_tracer_reset,
1224 .start = blk_tracer_start,
1225 .stop = blk_tracer_stop,
1226 .print_header = blk_tracer_print_header,
1227 .print_line = blk_tracer_print_line,
1228 .flags = &blk_tracer_flags,
1229};
1230
1231static struct trace_event trace_blk_event = {
1232 .type = TRACE_BLK,
1233 .trace = blk_trace_event_print,
1234 .latency_trace = blk_trace_event_print,
1235 .binary = blk_trace_event_print_binary,
1236};
1237
1238static int __init init_blk_tracer(void)
1239{
1240 if (!register_ftrace_event(&trace_blk_event)) {
1241 pr_warning("Warning: could not register block events\n");
1242 return 1;
1243 }
1244
1245 if (register_tracer(&blk_tracer) != 0) {
1246 pr_warning("Warning: could not register the block tracer\n");
1247 unregister_ftrace_event(&trace_blk_event);
1248 return 1;
1249 }
1250
1251 return 0;
1252}
1253
1254device_initcall(init_blk_tracer);
1255
1256static int blk_trace_remove_queue(struct request_queue *q)
1257{
1258 struct blk_trace *bt;
1259
1260 bt = xchg(&q->blk_trace, NULL);
1261 if (bt == NULL)
1262 return -EINVAL;
1263
1264 kfree(bt);
1265 return 0;
1266}
1267
1268/*
1269 * Setup everything required to start tracing
1270 */
1271static int blk_trace_setup_queue(struct request_queue *q, dev_t dev)
1272{
1273 struct blk_trace *old_bt, *bt = NULL;
1274 int ret;
1275
1276 ret = -ENOMEM;
1277 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1278 if (!bt)
1279 goto err;
1280
1281 bt->dev = dev;
1282 bt->act_mask = (u16)-1;
1283 bt->end_lba = -1ULL;
1284 bt->trace_state = Blktrace_running;
1285
1286 old_bt = xchg(&q->blk_trace, bt);
1287 if (old_bt != NULL) {
1288 (void)xchg(&q->blk_trace, old_bt);
1289 kfree(bt);
1290 ret = -EBUSY;
1291 }
1292 return 0;
1293err:
1294 return ret;
1295}
1296
1297/*
1298 * sysfs interface to enable and configure tracing
1299 */
1300
1301static ssize_t sysfs_blk_trace_enable_show(struct device *dev,
1302 struct device_attribute *attr,
1303 char *buf)
1304{
1305 struct hd_struct *p = dev_to_part(dev);
1306 struct block_device *bdev;
1307 ssize_t ret = -ENXIO;
1308
1309 lock_kernel();
1310 bdev = bdget(part_devt(p));
1311 if (bdev != NULL) {
1312 struct request_queue *q = bdev_get_queue(bdev);
1313
1314 if (q != NULL) {
1315 mutex_lock(&bdev->bd_mutex);
1316 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1317 mutex_unlock(&bdev->bd_mutex);
1318 }
1319
1320 bdput(bdev);
1321 }
1322
1323 unlock_kernel();
1324 return ret;
1325}
1326
1327static ssize_t sysfs_blk_trace_enable_store(struct device *dev,
1328 struct device_attribute *attr,
1329 const char *buf, size_t count)
1330{
1331 struct block_device *bdev;
1332 struct request_queue *q;
1333 struct hd_struct *p;
1334 int value;
1335 ssize_t ret = -ENXIO;
1336
1337 if (count == 0 || sscanf(buf, "%d", &value) != 1)
1338 goto out;
1339
1340 lock_kernel();
1341 p = dev_to_part(dev);
1342 bdev = bdget(part_devt(p));
1343 if (bdev == NULL)
1344 goto out_unlock_kernel;
1345
1346 q = bdev_get_queue(bdev);
1347 if (q == NULL)
1348 goto out_bdput;
1349
1350 mutex_lock(&bdev->bd_mutex);
1351 if (value)
1352 ret = blk_trace_setup_queue(q, bdev->bd_dev);
1353 else
1354 ret = blk_trace_remove_queue(q);
1355 mutex_unlock(&bdev->bd_mutex);
1356
1357 if (ret == 0)
1358 ret = count;
1359out_bdput:
1360 bdput(bdev);
1361out_unlock_kernel:
1362 unlock_kernel();
1363out:
1364 return ret;
1365}
1366
1367static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1368 struct device_attribute *attr,
1369 char *buf);
1370static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1371 struct device_attribute *attr,
1372 const char *buf, size_t count);
1373#define BLK_TRACE_DEVICE_ATTR(_name) \
1374 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1375 sysfs_blk_trace_attr_show, \
1376 sysfs_blk_trace_attr_store)
1377
1378static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
1379 sysfs_blk_trace_enable_show, sysfs_blk_trace_enable_store);
1380static BLK_TRACE_DEVICE_ATTR(act_mask);
1381static BLK_TRACE_DEVICE_ATTR(pid);
1382static BLK_TRACE_DEVICE_ATTR(start_lba);
1383static BLK_TRACE_DEVICE_ATTR(end_lba);
1384
1385static struct attribute *blk_trace_attrs[] = {
1386 &dev_attr_enable.attr,
1387 &dev_attr_act_mask.attr,
1388 &dev_attr_pid.attr,
1389 &dev_attr_start_lba.attr,
1390 &dev_attr_end_lba.attr,
1391 NULL
1392};
1393
1394struct attribute_group blk_trace_attr_group = {
1395 .name = "trace",
1396 .attrs = blk_trace_attrs,
1397};
1398
1399static int blk_str2act_mask(const char *str)
1400{
1401 int mask = 0;
1402 char *copy = kstrdup(str, GFP_KERNEL), *s;
1403
1404 if (copy == NULL)
1405 return -ENOMEM;
1406
1407 s = strstrip(copy);
1408
1409 while (1) {
1410 char *sep = strchr(s, ',');
1411
1412 if (sep != NULL)
1413 *sep = '\0';
1414
1415 if (strcasecmp(s, "barrier") == 0)
1416 mask |= BLK_TC_BARRIER;
1417 else if (strcasecmp(s, "complete") == 0)
1418 mask |= BLK_TC_COMPLETE;
1419 else if (strcasecmp(s, "fs") == 0)
1420 mask |= BLK_TC_FS;
1421 else if (strcasecmp(s, "issue") == 0)
1422 mask |= BLK_TC_ISSUE;
1423 else if (strcasecmp(s, "pc") == 0)
1424 mask |= BLK_TC_PC;
1425 else if (strcasecmp(s, "queue") == 0)
1426 mask |= BLK_TC_QUEUE;
1427 else if (strcasecmp(s, "read") == 0)
1428 mask |= BLK_TC_READ;
1429 else if (strcasecmp(s, "requeue") == 0)
1430 mask |= BLK_TC_REQUEUE;
1431 else if (strcasecmp(s, "sync") == 0)
1432 mask |= BLK_TC_SYNC;
1433 else if (strcasecmp(s, "write") == 0)
1434 mask |= BLK_TC_WRITE;
1435
1436 if (sep == NULL)
1437 break;
1438
1439 s = sep + 1;
1440 }
1441 kfree(copy);
1442
1443 return mask;
1444}
1445
1446static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1447 struct device_attribute *attr,
1448 char *buf)
1449{
1450 struct hd_struct *p = dev_to_part(dev);
1451 struct request_queue *q;
1452 struct block_device *bdev;
1453 ssize_t ret = -ENXIO;
1454
1455 lock_kernel();
1456 bdev = bdget(part_devt(p));
1457 if (bdev == NULL)
1458 goto out_unlock_kernel;
1459
1460 q = bdev_get_queue(bdev);
1461 if (q == NULL)
1462 goto out_bdput;
1463 mutex_lock(&bdev->bd_mutex);
1464 if (q->blk_trace == NULL)
1465 ret = sprintf(buf, "disabled\n");
1466 else if (attr == &dev_attr_act_mask)
1467 ret = sprintf(buf, "%#x\n", q->blk_trace->act_mask);
1468 else if (attr == &dev_attr_pid)
1469 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1470 else if (attr == &dev_attr_start_lba)
1471 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1472 else if (attr == &dev_attr_end_lba)
1473 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1474 mutex_unlock(&bdev->bd_mutex);
1475out_bdput:
1476 bdput(bdev);
1477out_unlock_kernel:
1478 unlock_kernel();
1479 return ret;
1480}
1481
1482static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1483 struct device_attribute *attr,
1484 const char *buf, size_t count)
1485{
1486 struct block_device *bdev;
1487 struct request_queue *q;
1488 struct hd_struct *p;
1489 u64 value;
1490 ssize_t ret = -ENXIO;
1491
1492 if (count == 0)
1493 goto out;
1494
1495 if (attr == &dev_attr_act_mask) {
1496 if (sscanf(buf, "%llx", &value) != 1) {
1497 /* Assume it is a list of trace category names */
1498 value = blk_str2act_mask(buf);
1499 if (value < 0)
1500 goto out;
1501 }
1502 } else if (sscanf(buf, "%llu", &value) != 1)
1503 goto out;
1504
1505 lock_kernel();
1506 p = dev_to_part(dev);
1507 bdev = bdget(part_devt(p));
1508 if (bdev == NULL)
1509 goto out_unlock_kernel;
1510
1511 q = bdev_get_queue(bdev);
1512 if (q == NULL)
1513 goto out_bdput;
1514
1515 mutex_lock(&bdev->bd_mutex);
1516 ret = 0;
1517 if (q->blk_trace == NULL)
1518 ret = blk_trace_setup_queue(q, bdev->bd_dev);
1519
1520 if (ret == 0) {
1521 if (attr == &dev_attr_act_mask)
1522 q->blk_trace->act_mask = value;
1523 else if (attr == &dev_attr_pid)
1524 q->blk_trace->pid = value;
1525 else if (attr == &dev_attr_start_lba)
1526 q->blk_trace->start_lba = value;
1527 else if (attr == &dev_attr_end_lba)
1528 q->blk_trace->end_lba = value;
1529 ret = count;
1530 }
1531 mutex_unlock(&bdev->bd_mutex);
1532out_bdput:
1533 bdput(bdev);
1534out_unlock_kernel:
1535 unlock_kernel();
1536out:
1537 return ret;
1538}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-26 18:51:18 -0500