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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/export.h>
27#include <linux/time.h>
28#include <linux/uaccess.h>
29#include <linux/list.h>
30#include <linux/blk-cgroup.h>
31
32#include "../../block/blk.h"
33
34#include <trace/events/block.h>
35
36#include "trace_output.h"
37
38#ifdef CONFIG_BLK_DEV_IO_TRACE
39
40static unsigned int blktrace_seq __read_mostly = 1;
41
42static struct trace_array *blk_tr;
43static bool blk_tracer_enabled __read_mostly;
44
45static LIST_HEAD(running_trace_list);
46static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
47
48/* Select an alternative, minimalistic output than the original one */
49#define TRACE_BLK_OPT_CLASSIC 0x1
50#define TRACE_BLK_OPT_CGROUP 0x2
51#define TRACE_BLK_OPT_CGNAME 0x4
52
53static struct tracer_opt blk_tracer_opts[] = {
54 /* Default disable the minimalistic output */
55 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
56#ifdef CONFIG_BLK_CGROUP
57 { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
58 { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
59#endif
60 { }
61};
62
63static struct tracer_flags blk_tracer_flags = {
64 .val = 0,
65 .opts = blk_tracer_opts,
66};
67
68/* Global reference count of probes */
69static DEFINE_MUTEX(blk_probe_mutex);
70static int blk_probes_ref;
71
72static void blk_register_tracepoints(void);
73static void blk_unregister_tracepoints(void);
74
75/*
76 * Send out a notify message.
77 */
78static void trace_note(struct blk_trace *bt, pid_t pid, int action,
79 const void *data, size_t len,
80 union kernfs_node_id *cgid)
81{
82 struct blk_io_trace *t;
83 struct ring_buffer_event *event = NULL;
84 struct ring_buffer *buffer = NULL;
85 int pc = 0;
86 int cpu = smp_processor_id();
87 bool blk_tracer = blk_tracer_enabled;
88 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
89
90 if (blk_tracer) {
91 buffer = blk_tr->trace_buffer.buffer;
92 pc = preempt_count();
93 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
94 sizeof(*t) + len + cgid_len,
95 0, pc);
96 if (!event)
97 return;
98 t = ring_buffer_event_data(event);
99 goto record_it;
100 }
101
102 if (!bt->rchan)
103 return;
104
105 t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len);
106 if (t) {
107 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
108 t->time = ktime_to_ns(ktime_get());
109record_it:
110 t->device = bt->dev;
111 t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
112 t->pid = pid;
113 t->cpu = cpu;
114 t->pdu_len = len + cgid_len;
115 if (cgid)
116 memcpy((void *)t + sizeof(*t), cgid, cgid_len);
117 memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
118
119 if (blk_tracer)
120 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
121 }
122}
123
124/*
125 * Send out a notify for this process, if we haven't done so since a trace
126 * started
127 */
128static void trace_note_tsk(struct task_struct *tsk)
129{
130 unsigned long flags;
131 struct blk_trace *bt;
132
133 tsk->btrace_seq = blktrace_seq;
134 spin_lock_irqsave(&running_trace_lock, flags);
135 list_for_each_entry(bt, &running_trace_list, running_list) {
136 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
137 sizeof(tsk->comm), NULL);
138 }
139 spin_unlock_irqrestore(&running_trace_lock, flags);
140}
141
142static void trace_note_time(struct blk_trace *bt)
143{
144 struct timespec64 now;
145 unsigned long flags;
146 u32 words[2];
147
148 /* need to check user space to see if this breaks in y2038 or y2106 */
149 ktime_get_real_ts64(&now);
150 words[0] = (u32)now.tv_sec;
151 words[1] = now.tv_nsec;
152
153 local_irq_save(flags);
154 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), NULL);
155 local_irq_restore(flags);
156}
157
158void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
159 const char *fmt, ...)
160{
161 int n;
162 va_list args;
163 unsigned long flags;
164 char *buf;
165
166 if (unlikely(bt->trace_state != Blktrace_running &&
167 !blk_tracer_enabled))
168 return;
169
170 /*
171 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
172 * message to the trace.
173 */
174 if (!(bt->act_mask & BLK_TC_NOTIFY))
175 return;
176
177 local_irq_save(flags);
178 buf = this_cpu_ptr(bt->msg_data);
179 va_start(args, fmt);
180 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
181 va_end(args);
182
183 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
184 blkcg = NULL;
185#ifdef CONFIG_BLK_CGROUP
186 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n,
187 blkcg ? cgroup_get_kernfs_id(blkcg->css.cgroup) : NULL);
188#else
189 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL);
190#endif
191 local_irq_restore(flags);
192}
193EXPORT_SYMBOL_GPL(__trace_note_message);
194
195static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
196 pid_t pid)
197{
198 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
199 return 1;
200 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
201 return 1;
202 if (bt->pid && pid != bt->pid)
203 return 1;
204
205 return 0;
206}
207
208/*
209 * Data direction bit lookup
210 */
211static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
212 BLK_TC_ACT(BLK_TC_WRITE) };
213
214#define BLK_TC_RAHEAD BLK_TC_AHEAD
215#define BLK_TC_PREFLUSH BLK_TC_FLUSH
216
217/* The ilog2() calls fall out because they're constant */
218#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
219 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
220
221/*
222 * The worker for the various blk_add_trace*() types. Fills out a
223 * blk_io_trace structure and places it in a per-cpu subbuffer.
224 */
225static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
226 int op, int op_flags, u32 what, int error, int pdu_len,
227 void *pdu_data, union kernfs_node_id *cgid)
228{
229 struct task_struct *tsk = current;
230 struct ring_buffer_event *event = NULL;
231 struct ring_buffer *buffer = NULL;
232 struct blk_io_trace *t;
233 unsigned long flags = 0;
234 unsigned long *sequence;
235 pid_t pid;
236 int cpu, pc = 0;
237 bool blk_tracer = blk_tracer_enabled;
238 ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
239
240 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
241 return;
242
243 what |= ddir_act[op_is_write(op) ? WRITE : READ];
244 what |= MASK_TC_BIT(op_flags, SYNC);
245 what |= MASK_TC_BIT(op_flags, RAHEAD);
246 what |= MASK_TC_BIT(op_flags, META);
247 what |= MASK_TC_BIT(op_flags, PREFLUSH);
248 what |= MASK_TC_BIT(op_flags, FUA);
249 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
250 what |= BLK_TC_ACT(BLK_TC_DISCARD);
251 if (op == REQ_OP_FLUSH)
252 what |= BLK_TC_ACT(BLK_TC_FLUSH);
253 if (cgid)
254 what |= __BLK_TA_CGROUP;
255
256 pid = tsk->pid;
257 if (act_log_check(bt, what, sector, pid))
258 return;
259 cpu = raw_smp_processor_id();
260
261 if (blk_tracer) {
262 tracing_record_cmdline(current);
263
264 buffer = blk_tr->trace_buffer.buffer;
265 pc = preempt_count();
266 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
267 sizeof(*t) + pdu_len + cgid_len,
268 0, pc);
269 if (!event)
270 return;
271 t = ring_buffer_event_data(event);
272 goto record_it;
273 }
274
275 if (unlikely(tsk->btrace_seq != blktrace_seq))
276 trace_note_tsk(tsk);
277
278 /*
279 * A word about the locking here - we disable interrupts to reserve
280 * some space in the relay per-cpu buffer, to prevent an irq
281 * from coming in and stepping on our toes.
282 */
283 local_irq_save(flags);
284 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
285 if (t) {
286 sequence = per_cpu_ptr(bt->sequence, cpu);
287
288 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
289 t->sequence = ++(*sequence);
290 t->time = ktime_to_ns(ktime_get());
291record_it:
292 /*
293 * These two are not needed in ftrace as they are in the
294 * generic trace_entry, filled by tracing_generic_entry_update,
295 * but for the trace_event->bin() synthesizer benefit we do it
296 * here too.
297 */
298 t->cpu = cpu;
299 t->pid = pid;
300
301 t->sector = sector;
302 t->bytes = bytes;
303 t->action = what;
304 t->device = bt->dev;
305 t->error = error;
306 t->pdu_len = pdu_len + cgid_len;
307
308 if (cgid_len)
309 memcpy((void *)t + sizeof(*t), cgid, cgid_len);
310 if (pdu_len)
311 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
312
313 if (blk_tracer) {
314 trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
315 return;
316 }
317 }
318
319 local_irq_restore(flags);
320}
321
322static void blk_trace_free(struct blk_trace *bt)
323{
324 debugfs_remove(bt->msg_file);
325 debugfs_remove(bt->dropped_file);
326 relay_close(bt->rchan);
327 debugfs_remove(bt->dir);
328 free_percpu(bt->sequence);
329 free_percpu(bt->msg_data);
330 kfree(bt);
331}
332
333static void get_probe_ref(void)
334{
335 mutex_lock(&blk_probe_mutex);
336 if (++blk_probes_ref == 1)
337 blk_register_tracepoints();
338 mutex_unlock(&blk_probe_mutex);
339}
340
341static void put_probe_ref(void)
342{
343 mutex_lock(&blk_probe_mutex);
344 if (!--blk_probes_ref)
345 blk_unregister_tracepoints();
346 mutex_unlock(&blk_probe_mutex);
347}
348
349static void blk_trace_cleanup(struct blk_trace *bt)
350{
351 blk_trace_free(bt);
352 put_probe_ref();
353}
354
355static int __blk_trace_remove(struct request_queue *q)
356{
357 struct blk_trace *bt;
358
359 bt = xchg(&q->blk_trace, NULL);
360 if (!bt)
361 return -EINVAL;
362
363 if (bt->trace_state != Blktrace_running)
364 blk_trace_cleanup(bt);
365
366 return 0;
367}
368
369int blk_trace_remove(struct request_queue *q)
370{
371 int ret;
372
373 mutex_lock(&q->blk_trace_mutex);
374 ret = __blk_trace_remove(q);
375 mutex_unlock(&q->blk_trace_mutex);
376
377 return ret;
378}
379EXPORT_SYMBOL_GPL(blk_trace_remove);
380
381static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
382 size_t count, loff_t *ppos)
383{
384 struct blk_trace *bt = filp->private_data;
385 char buf[16];
386
387 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
388
389 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
390}
391
392static const struct file_operations blk_dropped_fops = {
393 .owner = THIS_MODULE,
394 .open = simple_open,
395 .read = blk_dropped_read,
396 .llseek = default_llseek,
397};
398
399static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
400 size_t count, loff_t *ppos)
401{
402 char *msg;
403 struct blk_trace *bt;
404
405 if (count >= BLK_TN_MAX_MSG)
406 return -EINVAL;
407
408 msg = memdup_user_nul(buffer, count);
409 if (IS_ERR(msg))
410 return PTR_ERR(msg);
411
412 bt = filp->private_data;
413 __trace_note_message(bt, NULL, "%s", msg);
414 kfree(msg);
415
416 return count;
417}
418
419static const struct file_operations blk_msg_fops = {
420 .owner = THIS_MODULE,
421 .open = simple_open,
422 .write = blk_msg_write,
423 .llseek = noop_llseek,
424};
425
426/*
427 * Keep track of how many times we encountered a full subbuffer, to aid
428 * the user space app in telling how many lost events there were.
429 */
430static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
431 void *prev_subbuf, size_t prev_padding)
432{
433 struct blk_trace *bt;
434
435 if (!relay_buf_full(buf))
436 return 1;
437
438 bt = buf->chan->private_data;
439 atomic_inc(&bt->dropped);
440 return 0;
441}
442
443static int blk_remove_buf_file_callback(struct dentry *dentry)
444{
445 debugfs_remove(dentry);
446
447 return 0;
448}
449
450static struct dentry *blk_create_buf_file_callback(const char *filename,
451 struct dentry *parent,
452 umode_t mode,
453 struct rchan_buf *buf,
454 int *is_global)
455{
456 return debugfs_create_file(filename, mode, parent, buf,
457 &relay_file_operations);
458}
459
460static struct rchan_callbacks blk_relay_callbacks = {
461 .subbuf_start = blk_subbuf_start_callback,
462 .create_buf_file = blk_create_buf_file_callback,
463 .remove_buf_file = blk_remove_buf_file_callback,
464};
465
466static void blk_trace_setup_lba(struct blk_trace *bt,
467 struct block_device *bdev)
468{
469 struct hd_struct *part = NULL;
470
471 if (bdev)
472 part = bdev->bd_part;
473
474 if (part) {
475 bt->start_lba = part->start_sect;
476 bt->end_lba = part->start_sect + part->nr_sects;
477 } else {
478 bt->start_lba = 0;
479 bt->end_lba = -1ULL;
480 }
481}
482
483/*
484 * Setup everything required to start tracing
485 */
486static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
487 struct block_device *bdev,
488 struct blk_user_trace_setup *buts)
489{
490 struct blk_trace *bt = NULL;
491 struct dentry *dir = NULL;
492 int ret;
493
494 if (!buts->buf_size || !buts->buf_nr)
495 return -EINVAL;
496
497 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
498 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
499
500 /*
501 * some device names have larger paths - convert the slashes
502 * to underscores for this to work as expected
503 */
504 strreplace(buts->name, '/', '_');
505
506 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
507 if (!bt)
508 return -ENOMEM;
509
510 ret = -ENOMEM;
511 bt->sequence = alloc_percpu(unsigned long);
512 if (!bt->sequence)
513 goto err;
514
515 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
516 if (!bt->msg_data)
517 goto err;
518
519 ret = -ENOENT;
520
521 if (!blk_debugfs_root)
522 goto err;
523
524 dir = debugfs_lookup(buts->name, blk_debugfs_root);
525 if (!dir)
526 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
527 if (!dir)
528 goto err;
529
530 bt->dev = dev;
531 atomic_set(&bt->dropped, 0);
532 INIT_LIST_HEAD(&bt->running_list);
533
534 ret = -EIO;
535 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
536 &blk_dropped_fops);
537 if (!bt->dropped_file)
538 goto err;
539
540 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
541 if (!bt->msg_file)
542 goto err;
543
544 bt->rchan = relay_open("trace", dir, buts->buf_size,
545 buts->buf_nr, &blk_relay_callbacks, bt);
546 if (!bt->rchan)
547 goto err;
548
549 bt->act_mask = buts->act_mask;
550 if (!bt->act_mask)
551 bt->act_mask = (u16) -1;
552
553 blk_trace_setup_lba(bt, bdev);
554
555 /* overwrite with user settings */
556 if (buts->start_lba)
557 bt->start_lba = buts->start_lba;
558 if (buts->end_lba)
559 bt->end_lba = buts->end_lba;
560
561 bt->pid = buts->pid;
562 bt->trace_state = Blktrace_setup;
563
564 ret = -EBUSY;
565 if (cmpxchg(&q->blk_trace, NULL, bt))
566 goto err;
567
568 get_probe_ref();
569
570 ret = 0;
571err:
572 if (dir && !bt->dir)
573 dput(dir);
574 if (ret)
575 blk_trace_free(bt);
576 return ret;
577}
578
579static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
580 struct block_device *bdev, char __user *arg)
581{
582 struct blk_user_trace_setup buts;
583 int ret;
584
585 ret = copy_from_user(&buts, arg, sizeof(buts));
586 if (ret)
587 return -EFAULT;
588
589 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
590 if (ret)
591 return ret;
592
593 if (copy_to_user(arg, &buts, sizeof(buts))) {
594 __blk_trace_remove(q);
595 return -EFAULT;
596 }
597 return 0;
598}
599
600int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
601 struct block_device *bdev,
602 char __user *arg)
603{
604 int ret;
605
606 mutex_lock(&q->blk_trace_mutex);
607 ret = __blk_trace_setup(q, name, dev, bdev, arg);
608 mutex_unlock(&q->blk_trace_mutex);
609
610 return ret;
611}
612EXPORT_SYMBOL_GPL(blk_trace_setup);
613
614#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
615static int compat_blk_trace_setup(struct request_queue *q, char *name,
616 dev_t dev, struct block_device *bdev,
617 char __user *arg)
618{
619 struct blk_user_trace_setup buts;
620 struct compat_blk_user_trace_setup cbuts;
621 int ret;
622
623 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
624 return -EFAULT;
625
626 buts = (struct blk_user_trace_setup) {
627 .act_mask = cbuts.act_mask,
628 .buf_size = cbuts.buf_size,
629 .buf_nr = cbuts.buf_nr,
630 .start_lba = cbuts.start_lba,
631 .end_lba = cbuts.end_lba,
632 .pid = cbuts.pid,
633 };
634
635 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
636 if (ret)
637 return ret;
638
639 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
640 __blk_trace_remove(q);
641 return -EFAULT;
642 }
643
644 return 0;
645}
646#endif
647
648static int __blk_trace_startstop(struct request_queue *q, int start)
649{
650 int ret;
651 struct blk_trace *bt = q->blk_trace;
652
653 if (bt == NULL)
654 return -EINVAL;
655
656 /*
657 * For starting a trace, we can transition from a setup or stopped
658 * trace. For stopping a trace, the state must be running
659 */
660 ret = -EINVAL;
661 if (start) {
662 if (bt->trace_state == Blktrace_setup ||
663 bt->trace_state == Blktrace_stopped) {
664 blktrace_seq++;
665 smp_mb();
666 bt->trace_state = Blktrace_running;
667 spin_lock_irq(&running_trace_lock);
668 list_add(&bt->running_list, &running_trace_list);
669 spin_unlock_irq(&running_trace_lock);
670
671 trace_note_time(bt);
672 ret = 0;
673 }
674 } else {
675 if (bt->trace_state == Blktrace_running) {
676 bt->trace_state = Blktrace_stopped;
677 spin_lock_irq(&running_trace_lock);
678 list_del_init(&bt->running_list);
679 spin_unlock_irq(&running_trace_lock);
680 relay_flush(bt->rchan);
681 ret = 0;
682 }
683 }
684
685 return ret;
686}
687
688int blk_trace_startstop(struct request_queue *q, int start)
689{
690 int ret;
691
692 mutex_lock(&q->blk_trace_mutex);
693 ret = __blk_trace_startstop(q, start);
694 mutex_unlock(&q->blk_trace_mutex);
695
696 return ret;
697}
698EXPORT_SYMBOL_GPL(blk_trace_startstop);
699
700/*
701 * When reading or writing the blktrace sysfs files, the references to the
702 * opened sysfs or device files should prevent the underlying block device
703 * from being removed. So no further delete protection is really needed.
704 */
705
706/**
707 * blk_trace_ioctl: - handle the ioctls associated with tracing
708 * @bdev: the block device
709 * @cmd: the ioctl cmd
710 * @arg: the argument data, if any
711 *
712 **/
713int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
714{
715 struct request_queue *q;
716 int ret, start = 0;
717 char b[BDEVNAME_SIZE];
718
719 q = bdev_get_queue(bdev);
720 if (!q)
721 return -ENXIO;
722
723 mutex_lock(&q->blk_trace_mutex);
724
725 switch (cmd) {
726 case BLKTRACESETUP:
727 bdevname(bdev, b);
728 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
729 break;
730#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
731 case BLKTRACESETUP32:
732 bdevname(bdev, b);
733 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
734 break;
735#endif
736 case BLKTRACESTART:
737 start = 1;
738 case BLKTRACESTOP:
739 ret = __blk_trace_startstop(q, start);
740 break;
741 case BLKTRACETEARDOWN:
742 ret = __blk_trace_remove(q);
743 break;
744 default:
745 ret = -ENOTTY;
746 break;
747 }
748
749 mutex_unlock(&q->blk_trace_mutex);
750 return ret;
751}
752
753/**
754 * blk_trace_shutdown: - stop and cleanup trace structures
755 * @q: the request queue associated with the device
756 *
757 **/
758void blk_trace_shutdown(struct request_queue *q)
759{
760 mutex_lock(&q->blk_trace_mutex);
761
762 if (q->blk_trace) {
763 __blk_trace_startstop(q, 0);
764 __blk_trace_remove(q);
765 }
766
767 mutex_unlock(&q->blk_trace_mutex);
768}
769
770#ifdef CONFIG_BLK_CGROUP
771static union kernfs_node_id *
772blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
773{
774 struct blk_trace *bt = q->blk_trace;
775
776 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
777 return NULL;
778
779 if (!bio->bi_css)
780 return NULL;
781 return cgroup_get_kernfs_id(bio->bi_css->cgroup);
782}
783#else
784static union kernfs_node_id *
785blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
786{
787 return NULL;
788}
789#endif
790
791static union kernfs_node_id *
792blk_trace_request_get_cgid(struct request_queue *q, struct request *rq)
793{
794 if (!rq->bio)
795 return NULL;
796 /* Use the first bio */
797 return blk_trace_bio_get_cgid(q, rq->bio);
798}
799
800/*
801 * blktrace probes
802 */
803
804/**
805 * blk_add_trace_rq - Add a trace for a request oriented action
806 * @rq: the source request
807 * @error: return status to log
808 * @nr_bytes: number of completed bytes
809 * @what: the action
810 * @cgid: the cgroup info
811 *
812 * Description:
813 * Records an action against a request. Will log the bio offset + size.
814 *
815 **/
816static void blk_add_trace_rq(struct request *rq, int error,
817 unsigned int nr_bytes, u32 what,
818 union kernfs_node_id *cgid)
819{
820 struct blk_trace *bt = rq->q->blk_trace;
821
822 if (likely(!bt))
823 return;
824
825 if (blk_rq_is_passthrough(rq))
826 what |= BLK_TC_ACT(BLK_TC_PC);
827 else
828 what |= BLK_TC_ACT(BLK_TC_FS);
829
830 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
831 rq->cmd_flags, what, error, 0, NULL, cgid);
832}
833
834static void blk_add_trace_rq_insert(void *ignore,
835 struct request_queue *q, struct request *rq)
836{
837 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
838 blk_trace_request_get_cgid(q, rq));
839}
840
841static void blk_add_trace_rq_issue(void *ignore,
842 struct request_queue *q, struct request *rq)
843{
844 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
845 blk_trace_request_get_cgid(q, rq));
846}
847
848static void blk_add_trace_rq_requeue(void *ignore,
849 struct request_queue *q,
850 struct request *rq)
851{
852 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
853 blk_trace_request_get_cgid(q, rq));
854}
855
856static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
857 int error, unsigned int nr_bytes)
858{
859 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
860 blk_trace_request_get_cgid(rq->q, rq));
861}
862
863/**
864 * blk_add_trace_bio - Add a trace for a bio oriented action
865 * @q: queue the io is for
866 * @bio: the source bio
867 * @what: the action
868 * @error: error, if any
869 *
870 * Description:
871 * Records an action against a bio. Will log the bio offset + size.
872 *
873 **/
874static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
875 u32 what, int error)
876{
877 struct blk_trace *bt = q->blk_trace;
878
879 if (likely(!bt))
880 return;
881
882 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
883 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
884 blk_trace_bio_get_cgid(q, bio));
885}
886
887static void blk_add_trace_bio_bounce(void *ignore,
888 struct request_queue *q, struct bio *bio)
889{
890 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
891}
892
893static void blk_add_trace_bio_complete(void *ignore,
894 struct request_queue *q, struct bio *bio,
895 int error)
896{
897 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
898}
899
900static void blk_add_trace_bio_backmerge(void *ignore,
901 struct request_queue *q,
902 struct request *rq,
903 struct bio *bio)
904{
905 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
906}
907
908static void blk_add_trace_bio_frontmerge(void *ignore,
909 struct request_queue *q,
910 struct request *rq,
911 struct bio *bio)
912{
913 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
914}
915
916static void blk_add_trace_bio_queue(void *ignore,
917 struct request_queue *q, struct bio *bio)
918{
919 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
920}
921
922static void blk_add_trace_getrq(void *ignore,
923 struct request_queue *q,
924 struct bio *bio, int rw)
925{
926 if (bio)
927 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
928 else {
929 struct blk_trace *bt = q->blk_trace;
930
931 if (bt)
932 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
933 NULL, NULL);
934 }
935}
936
937
938static void blk_add_trace_sleeprq(void *ignore,
939 struct request_queue *q,
940 struct bio *bio, int rw)
941{
942 if (bio)
943 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
944 else {
945 struct blk_trace *bt = q->blk_trace;
946
947 if (bt)
948 __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
949 0, 0, NULL, NULL);
950 }
951}
952
953static void blk_add_trace_plug(void *ignore, struct request_queue *q)
954{
955 struct blk_trace *bt = q->blk_trace;
956
957 if (bt)
958 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, NULL);
959}
960
961static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
962 unsigned int depth, bool explicit)
963{
964 struct blk_trace *bt = q->blk_trace;
965
966 if (bt) {
967 __be64 rpdu = cpu_to_be64(depth);
968 u32 what;
969
970 if (explicit)
971 what = BLK_TA_UNPLUG_IO;
972 else
973 what = BLK_TA_UNPLUG_TIMER;
974
975 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, NULL);
976 }
977}
978
979static void blk_add_trace_split(void *ignore,
980 struct request_queue *q, struct bio *bio,
981 unsigned int pdu)
982{
983 struct blk_trace *bt = q->blk_trace;
984
985 if (bt) {
986 __be64 rpdu = cpu_to_be64(pdu);
987
988 __blk_add_trace(bt, bio->bi_iter.bi_sector,
989 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
990 BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu),
991 &rpdu, blk_trace_bio_get_cgid(q, bio));
992 }
993}
994
995/**
996 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
997 * @ignore: trace callback data parameter (not used)
998 * @q: queue the io is for
999 * @bio: the source bio
1000 * @dev: target device
1001 * @from: source sector
1002 *
1003 * Description:
1004 * Device mapper or raid target sometimes need to split a bio because
1005 * it spans a stripe (or similar). Add a trace for that action.
1006 *
1007 **/
1008static void blk_add_trace_bio_remap(void *ignore,
1009 struct request_queue *q, struct bio *bio,
1010 dev_t dev, sector_t from)
1011{
1012 struct blk_trace *bt = q->blk_trace;
1013 struct blk_io_trace_remap r;
1014
1015 if (likely(!bt))
1016 return;
1017
1018 r.device_from = cpu_to_be32(dev);
1019 r.device_to = cpu_to_be32(bio_dev(bio));
1020 r.sector_from = cpu_to_be64(from);
1021
1022 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1023 bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status,
1024 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1025}
1026
1027/**
1028 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1029 * @ignore: trace callback data parameter (not used)
1030 * @q: queue the io is for
1031 * @rq: the source request
1032 * @dev: target device
1033 * @from: source sector
1034 *
1035 * Description:
1036 * Device mapper remaps request to other devices.
1037 * Add a trace for that action.
1038 *
1039 **/
1040static void blk_add_trace_rq_remap(void *ignore,
1041 struct request_queue *q,
1042 struct request *rq, dev_t dev,
1043 sector_t from)
1044{
1045 struct blk_trace *bt = q->blk_trace;
1046 struct blk_io_trace_remap r;
1047
1048 if (likely(!bt))
1049 return;
1050
1051 r.device_from = cpu_to_be32(dev);
1052 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1053 r.sector_from = cpu_to_be64(from);
1054
1055 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1056 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1057 sizeof(r), &r, blk_trace_request_get_cgid(q, rq));
1058}
1059
1060/**
1061 * blk_add_driver_data - Add binary message with driver-specific data
1062 * @q: queue the io is for
1063 * @rq: io request
1064 * @data: driver-specific data
1065 * @len: length of driver-specific data
1066 *
1067 * Description:
1068 * Some drivers might want to write driver-specific data per request.
1069 *
1070 **/
1071void blk_add_driver_data(struct request_queue *q,
1072 struct request *rq,
1073 void *data, size_t len)
1074{
1075 struct blk_trace *bt = q->blk_trace;
1076
1077 if (likely(!bt))
1078 return;
1079
1080 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1081 BLK_TA_DRV_DATA, 0, len, data,
1082 blk_trace_request_get_cgid(q, rq));
1083}
1084EXPORT_SYMBOL_GPL(blk_add_driver_data);
1085
1086static void blk_register_tracepoints(void)
1087{
1088 int ret;
1089
1090 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1091 WARN_ON(ret);
1092 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1093 WARN_ON(ret);
1094 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1095 WARN_ON(ret);
1096 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1097 WARN_ON(ret);
1098 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1099 WARN_ON(ret);
1100 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1101 WARN_ON(ret);
1102 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1103 WARN_ON(ret);
1104 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1105 WARN_ON(ret);
1106 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1107 WARN_ON(ret);
1108 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1109 WARN_ON(ret);
1110 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1111 WARN_ON(ret);
1112 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1113 WARN_ON(ret);
1114 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1115 WARN_ON(ret);
1116 ret = register_trace_block_split(blk_add_trace_split, NULL);
1117 WARN_ON(ret);
1118 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1119 WARN_ON(ret);
1120 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1121 WARN_ON(ret);
1122}
1123
1124static void blk_unregister_tracepoints(void)
1125{
1126 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1127 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1128 unregister_trace_block_split(blk_add_trace_split, NULL);
1129 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1130 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1131 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1132 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1133 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1134 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1135 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1136 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1137 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1138 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1139 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1140 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1141 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1142
1143 tracepoint_synchronize_unregister();
1144}
1145
1146/*
1147 * struct blk_io_tracer formatting routines
1148 */
1149
1150static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1151{
1152 int i = 0;
1153 int tc = t->action >> BLK_TC_SHIFT;
1154
1155 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1156 rwbs[i++] = 'N';
1157 goto out;
1158 }
1159
1160 if (tc & BLK_TC_FLUSH)
1161 rwbs[i++] = 'F';
1162
1163 if (tc & BLK_TC_DISCARD)
1164 rwbs[i++] = 'D';
1165 else if (tc & BLK_TC_WRITE)
1166 rwbs[i++] = 'W';
1167 else if (t->bytes)
1168 rwbs[i++] = 'R';
1169 else
1170 rwbs[i++] = 'N';
1171
1172 if (tc & BLK_TC_FUA)
1173 rwbs[i++] = 'F';
1174 if (tc & BLK_TC_AHEAD)
1175 rwbs[i++] = 'A';
1176 if (tc & BLK_TC_SYNC)
1177 rwbs[i++] = 'S';
1178 if (tc & BLK_TC_META)
1179 rwbs[i++] = 'M';
1180out:
1181 rwbs[i] = '\0';
1182}
1183
1184static inline
1185const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1186{
1187 return (const struct blk_io_trace *)ent;
1188}
1189
1190static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1191{
1192 return (void *)(te_blk_io_trace(ent) + 1) +
1193 (has_cg ? sizeof(union kernfs_node_id) : 0);
1194}
1195
1196static inline const void *cgid_start(const struct trace_entry *ent)
1197{
1198 return (void *)(te_blk_io_trace(ent) + 1);
1199}
1200
1201static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1202{
1203 return te_blk_io_trace(ent)->pdu_len -
1204 (has_cg ? sizeof(union kernfs_node_id) : 0);
1205}
1206
1207static inline u32 t_action(const struct trace_entry *ent)
1208{
1209 return te_blk_io_trace(ent)->action;
1210}
1211
1212static inline u32 t_bytes(const struct trace_entry *ent)
1213{
1214 return te_blk_io_trace(ent)->bytes;
1215}
1216
1217static inline u32 t_sec(const struct trace_entry *ent)
1218{
1219 return te_blk_io_trace(ent)->bytes >> 9;
1220}
1221
1222static inline unsigned long long t_sector(const struct trace_entry *ent)
1223{
1224 return te_blk_io_trace(ent)->sector;
1225}
1226
1227static inline __u16 t_error(const struct trace_entry *ent)
1228{
1229 return te_blk_io_trace(ent)->error;
1230}
1231
1232static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1233{
1234 const __u64 *val = pdu_start(ent, has_cg);
1235 return be64_to_cpu(*val);
1236}
1237
1238static void get_pdu_remap(const struct trace_entry *ent,
1239 struct blk_io_trace_remap *r, bool has_cg)
1240{
1241 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1242 __u64 sector_from = __r->sector_from;
1243
1244 r->device_from = be32_to_cpu(__r->device_from);
1245 r->device_to = be32_to_cpu(__r->device_to);
1246 r->sector_from = be64_to_cpu(sector_from);
1247}
1248
1249typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1250 bool has_cg);
1251
1252static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1253 bool has_cg)
1254{
1255 char rwbs[RWBS_LEN];
1256 unsigned long long ts = iter->ts;
1257 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1258 unsigned secs = (unsigned long)ts;
1259 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1260
1261 fill_rwbs(rwbs, t);
1262
1263 trace_seq_printf(&iter->seq,
1264 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1265 MAJOR(t->device), MINOR(t->device), iter->cpu,
1266 secs, nsec_rem, iter->ent->pid, act, rwbs);
1267}
1268
1269static void blk_log_action(struct trace_iterator *iter, const char *act,
1270 bool has_cg)
1271{
1272 char rwbs[RWBS_LEN];
1273 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1274
1275 fill_rwbs(rwbs, t);
1276 if (has_cg) {
1277 const union kernfs_node_id *id = cgid_start(iter->ent);
1278
1279 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1280 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1281
1282 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1283 sizeof(blkcg_name_buf));
1284 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1285 MAJOR(t->device), MINOR(t->device),
1286 blkcg_name_buf, act, rwbs);
1287 } else
1288 trace_seq_printf(&iter->seq,
1289 "%3d,%-3d %x,%-x %2s %3s ",
1290 MAJOR(t->device), MINOR(t->device),
1291 id->ino, id->generation, act, rwbs);
1292 } else
1293 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1294 MAJOR(t->device), MINOR(t->device), act, rwbs);
1295}
1296
1297static void blk_log_dump_pdu(struct trace_seq *s,
1298 const struct trace_entry *ent, bool has_cg)
1299{
1300 const unsigned char *pdu_buf;
1301 int pdu_len;
1302 int i, end;
1303
1304 pdu_buf = pdu_start(ent, has_cg);
1305 pdu_len = pdu_real_len(ent, has_cg);
1306
1307 if (!pdu_len)
1308 return;
1309
1310 /* find the last zero that needs to be printed */
1311 for (end = pdu_len - 1; end >= 0; end--)
1312 if (pdu_buf[end])
1313 break;
1314 end++;
1315
1316 trace_seq_putc(s, '(');
1317
1318 for (i = 0; i < pdu_len; i++) {
1319
1320 trace_seq_printf(s, "%s%02x",
1321 i == 0 ? "" : " ", pdu_buf[i]);
1322
1323 /*
1324 * stop when the rest is just zeroes and indicate so
1325 * with a ".." appended
1326 */
1327 if (i == end && end != pdu_len - 1) {
1328 trace_seq_puts(s, " ..) ");
1329 return;
1330 }
1331 }
1332
1333 trace_seq_puts(s, ") ");
1334}
1335
1336static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1337{
1338 char cmd[TASK_COMM_LEN];
1339
1340 trace_find_cmdline(ent->pid, cmd);
1341
1342 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1343 trace_seq_printf(s, "%u ", t_bytes(ent));
1344 blk_log_dump_pdu(s, ent, has_cg);
1345 trace_seq_printf(s, "[%s]\n", cmd);
1346 } else {
1347 if (t_sec(ent))
1348 trace_seq_printf(s, "%llu + %u [%s]\n",
1349 t_sector(ent), t_sec(ent), cmd);
1350 else
1351 trace_seq_printf(s, "[%s]\n", cmd);
1352 }
1353}
1354
1355static void blk_log_with_error(struct trace_seq *s,
1356 const struct trace_entry *ent, bool has_cg)
1357{
1358 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1359 blk_log_dump_pdu(s, ent, has_cg);
1360 trace_seq_printf(s, "[%d]\n", t_error(ent));
1361 } else {
1362 if (t_sec(ent))
1363 trace_seq_printf(s, "%llu + %u [%d]\n",
1364 t_sector(ent),
1365 t_sec(ent), t_error(ent));
1366 else
1367 trace_seq_printf(s, "%llu [%d]\n",
1368 t_sector(ent), t_error(ent));
1369 }
1370}
1371
1372static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1373{
1374 struct blk_io_trace_remap r = { .device_from = 0, };
1375
1376 get_pdu_remap(ent, &r, has_cg);
1377 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1378 t_sector(ent), t_sec(ent),
1379 MAJOR(r.device_from), MINOR(r.device_from),
1380 (unsigned long long)r.sector_from);
1381}
1382
1383static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1384{
1385 char cmd[TASK_COMM_LEN];
1386
1387 trace_find_cmdline(ent->pid, cmd);
1388
1389 trace_seq_printf(s, "[%s]\n", cmd);
1390}
1391
1392static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1393{
1394 char cmd[TASK_COMM_LEN];
1395
1396 trace_find_cmdline(ent->pid, cmd);
1397
1398 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1399}
1400
1401static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1402{
1403 char cmd[TASK_COMM_LEN];
1404
1405 trace_find_cmdline(ent->pid, cmd);
1406
1407 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1408 get_pdu_int(ent, has_cg), cmd);
1409}
1410
1411static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1412 bool has_cg)
1413{
1414
1415 trace_seq_putmem(s, pdu_start(ent, has_cg),
1416 pdu_real_len(ent, has_cg));
1417 trace_seq_putc(s, '\n');
1418}
1419
1420/*
1421 * struct tracer operations
1422 */
1423
1424static void blk_tracer_print_header(struct seq_file *m)
1425{
1426 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1427 return;
1428 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1429 "# | | | | | |\n");
1430}
1431
1432static void blk_tracer_start(struct trace_array *tr)
1433{
1434 blk_tracer_enabled = true;
1435}
1436
1437static int blk_tracer_init(struct trace_array *tr)
1438{
1439 blk_tr = tr;
1440 blk_tracer_start(tr);
1441 return 0;
1442}
1443
1444static void blk_tracer_stop(struct trace_array *tr)
1445{
1446 blk_tracer_enabled = false;
1447}
1448
1449static void blk_tracer_reset(struct trace_array *tr)
1450{
1451 blk_tracer_stop(tr);
1452}
1453
1454static const struct {
1455 const char *act[2];
1456 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1457 bool has_cg);
1458} what2act[] = {
1459 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1460 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1461 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1462 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1463 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1464 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1465 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1466 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1467 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1468 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1469 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1470 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1471 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1472 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1473 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1474};
1475
1476static enum print_line_t print_one_line(struct trace_iterator *iter,
1477 bool classic)
1478{
1479 struct trace_array *tr = iter->tr;
1480 struct trace_seq *s = &iter->seq;
1481 const struct blk_io_trace *t;
1482 u16 what;
1483 bool long_act;
1484 blk_log_action_t *log_action;
1485 bool has_cg;
1486
1487 t = te_blk_io_trace(iter->ent);
1488 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1489 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1490 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1491 has_cg = t->action & __BLK_TA_CGROUP;
1492
1493 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1494 log_action(iter, long_act ? "message" : "m", has_cg);
1495 blk_log_msg(s, iter->ent, has_cg);
1496 return trace_handle_return(s);
1497 }
1498
1499 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1500 trace_seq_printf(s, "Unknown action %x\n", what);
1501 else {
1502 log_action(iter, what2act[what].act[long_act], has_cg);
1503 what2act[what].print(s, iter->ent, has_cg);
1504 }
1505
1506 return trace_handle_return(s);
1507}
1508
1509static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1510 int flags, struct trace_event *event)
1511{
1512 return print_one_line(iter, false);
1513}
1514
1515static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1516{
1517 struct trace_seq *s = &iter->seq;
1518 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1519 const int offset = offsetof(struct blk_io_trace, sector);
1520 struct blk_io_trace old = {
1521 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1522 .time = iter->ts,
1523 };
1524
1525 trace_seq_putmem(s, &old, offset);
1526 trace_seq_putmem(s, &t->sector,
1527 sizeof(old) - offset + t->pdu_len);
1528}
1529
1530static enum print_line_t
1531blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1532 struct trace_event *event)
1533{
1534 blk_trace_synthesize_old_trace(iter);
1535
1536 return trace_handle_return(&iter->seq);
1537}
1538
1539static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1540{
1541 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1542 return TRACE_TYPE_UNHANDLED;
1543
1544 return print_one_line(iter, true);
1545}
1546
1547static int
1548blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1549{
1550 /* don't output context-info for blk_classic output */
1551 if (bit == TRACE_BLK_OPT_CLASSIC) {
1552 if (set)
1553 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1554 else
1555 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1556 }
1557 return 0;
1558}
1559
1560static struct tracer blk_tracer __read_mostly = {
1561 .name = "blk",
1562 .init = blk_tracer_init,
1563 .reset = blk_tracer_reset,
1564 .start = blk_tracer_start,
1565 .stop = blk_tracer_stop,
1566 .print_header = blk_tracer_print_header,
1567 .print_line = blk_tracer_print_line,
1568 .flags = &blk_tracer_flags,
1569 .set_flag = blk_tracer_set_flag,
1570};
1571
1572static struct trace_event_functions trace_blk_event_funcs = {
1573 .trace = blk_trace_event_print,
1574 .binary = blk_trace_event_print_binary,
1575};
1576
1577static struct trace_event trace_blk_event = {
1578 .type = TRACE_BLK,
1579 .funcs = &trace_blk_event_funcs,
1580};
1581
1582static int __init init_blk_tracer(void)
1583{
1584 if (!register_trace_event(&trace_blk_event)) {
1585 pr_warn("Warning: could not register block events\n");
1586 return 1;
1587 }
1588
1589 if (register_tracer(&blk_tracer) != 0) {
1590 pr_warn("Warning: could not register the block tracer\n");
1591 unregister_trace_event(&trace_blk_event);
1592 return 1;
1593 }
1594
1595 return 0;
1596}
1597
1598device_initcall(init_blk_tracer);
1599
1600static int blk_trace_remove_queue(struct request_queue *q)
1601{
1602 struct blk_trace *bt;
1603
1604 bt = xchg(&q->blk_trace, NULL);
1605 if (bt == NULL)
1606 return -EINVAL;
1607
1608 put_probe_ref();
1609 blk_trace_free(bt);
1610 return 0;
1611}
1612
1613/*
1614 * Setup everything required to start tracing
1615 */
1616static int blk_trace_setup_queue(struct request_queue *q,
1617 struct block_device *bdev)
1618{
1619 struct blk_trace *bt = NULL;
1620 int ret = -ENOMEM;
1621
1622 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1623 if (!bt)
1624 return -ENOMEM;
1625
1626 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1627 if (!bt->msg_data)
1628 goto free_bt;
1629
1630 bt->dev = bdev->bd_dev;
1631 bt->act_mask = (u16)-1;
1632
1633 blk_trace_setup_lba(bt, bdev);
1634
1635 ret = -EBUSY;
1636 if (cmpxchg(&q->blk_trace, NULL, bt))
1637 goto free_bt;
1638
1639 get_probe_ref();
1640 return 0;
1641
1642free_bt:
1643 blk_trace_free(bt);
1644 return ret;
1645}
1646
1647/*
1648 * sysfs interface to enable and configure tracing
1649 */
1650
1651static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1652 struct device_attribute *attr,
1653 char *buf);
1654static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1655 struct device_attribute *attr,
1656 const char *buf, size_t count);
1657#define BLK_TRACE_DEVICE_ATTR(_name) \
1658 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1659 sysfs_blk_trace_attr_show, \
1660 sysfs_blk_trace_attr_store)
1661
1662static BLK_TRACE_DEVICE_ATTR(enable);
1663static BLK_TRACE_DEVICE_ATTR(act_mask);
1664static BLK_TRACE_DEVICE_ATTR(pid);
1665static BLK_TRACE_DEVICE_ATTR(start_lba);
1666static BLK_TRACE_DEVICE_ATTR(end_lba);
1667
1668static struct attribute *blk_trace_attrs[] = {
1669 &dev_attr_enable.attr,
1670 &dev_attr_act_mask.attr,
1671 &dev_attr_pid.attr,
1672 &dev_attr_start_lba.attr,
1673 &dev_attr_end_lba.attr,
1674 NULL
1675};
1676
1677struct attribute_group blk_trace_attr_group = {
1678 .name = "trace",
1679 .attrs = blk_trace_attrs,
1680};
1681
1682static const struct {
1683 int mask;
1684 const char *str;
1685} mask_maps[] = {
1686 { BLK_TC_READ, "read" },
1687 { BLK_TC_WRITE, "write" },
1688 { BLK_TC_FLUSH, "flush" },
1689 { BLK_TC_SYNC, "sync" },
1690 { BLK_TC_QUEUE, "queue" },
1691 { BLK_TC_REQUEUE, "requeue" },
1692 { BLK_TC_ISSUE, "issue" },
1693 { BLK_TC_COMPLETE, "complete" },
1694 { BLK_TC_FS, "fs" },
1695 { BLK_TC_PC, "pc" },
1696 { BLK_TC_NOTIFY, "notify" },
1697 { BLK_TC_AHEAD, "ahead" },
1698 { BLK_TC_META, "meta" },
1699 { BLK_TC_DISCARD, "discard" },
1700 { BLK_TC_DRV_DATA, "drv_data" },
1701 { BLK_TC_FUA, "fua" },
1702};
1703
1704static int blk_trace_str2mask(const char *str)
1705{
1706 int i;
1707 int mask = 0;
1708 char *buf, *s, *token;
1709
1710 buf = kstrdup(str, GFP_KERNEL);
1711 if (buf == NULL)
1712 return -ENOMEM;
1713 s = strstrip(buf);
1714
1715 while (1) {
1716 token = strsep(&s, ",");
1717 if (token == NULL)
1718 break;
1719
1720 if (*token == '\0')
1721 continue;
1722
1723 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1724 if (strcasecmp(token, mask_maps[i].str) == 0) {
1725 mask |= mask_maps[i].mask;
1726 break;
1727 }
1728 }
1729 if (i == ARRAY_SIZE(mask_maps)) {
1730 mask = -EINVAL;
1731 break;
1732 }
1733 }
1734 kfree(buf);
1735
1736 return mask;
1737}
1738
1739static ssize_t blk_trace_mask2str(char *buf, int mask)
1740{
1741 int i;
1742 char *p = buf;
1743
1744 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1745 if (mask & mask_maps[i].mask) {
1746 p += sprintf(p, "%s%s",
1747 (p == buf) ? "" : ",", mask_maps[i].str);
1748 }
1749 }
1750 *p++ = '\n';
1751
1752 return p - buf;
1753}
1754
1755static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1756{
1757 if (bdev->bd_disk == NULL)
1758 return NULL;
1759
1760 return bdev_get_queue(bdev);
1761}
1762
1763static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1764 struct device_attribute *attr,
1765 char *buf)
1766{
1767 struct hd_struct *p = dev_to_part(dev);
1768 struct request_queue *q;
1769 struct block_device *bdev;
1770 ssize_t ret = -ENXIO;
1771
1772 bdev = bdget(part_devt(p));
1773 if (bdev == NULL)
1774 goto out;
1775
1776 q = blk_trace_get_queue(bdev);
1777 if (q == NULL)
1778 goto out_bdput;
1779
1780 mutex_lock(&q->blk_trace_mutex);
1781
1782 if (attr == &dev_attr_enable) {
1783 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1784 goto out_unlock_bdev;
1785 }
1786
1787 if (q->blk_trace == NULL)
1788 ret = sprintf(buf, "disabled\n");
1789 else if (attr == &dev_attr_act_mask)
1790 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1791 else if (attr == &dev_attr_pid)
1792 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1793 else if (attr == &dev_attr_start_lba)
1794 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1795 else if (attr == &dev_attr_end_lba)
1796 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1797
1798out_unlock_bdev:
1799 mutex_unlock(&q->blk_trace_mutex);
1800out_bdput:
1801 bdput(bdev);
1802out:
1803 return ret;
1804}
1805
1806static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1807 struct device_attribute *attr,
1808 const char *buf, size_t count)
1809{
1810 struct block_device *bdev;
1811 struct request_queue *q;
1812 struct hd_struct *p;
1813 u64 value;
1814 ssize_t ret = -EINVAL;
1815
1816 if (count == 0)
1817 goto out;
1818
1819 if (attr == &dev_attr_act_mask) {
1820 if (kstrtoull(buf, 0, &value)) {
1821 /* Assume it is a list of trace category names */
1822 ret = blk_trace_str2mask(buf);
1823 if (ret < 0)
1824 goto out;
1825 value = ret;
1826 }
1827 } else if (kstrtoull(buf, 0, &value))
1828 goto out;
1829
1830 ret = -ENXIO;
1831
1832 p = dev_to_part(dev);
1833 bdev = bdget(part_devt(p));
1834 if (bdev == NULL)
1835 goto out;
1836
1837 q = blk_trace_get_queue(bdev);
1838 if (q == NULL)
1839 goto out_bdput;
1840
1841 mutex_lock(&q->blk_trace_mutex);
1842
1843 if (attr == &dev_attr_enable) {
1844 if (value)
1845 ret = blk_trace_setup_queue(q, bdev);
1846 else
1847 ret = blk_trace_remove_queue(q);
1848 goto out_unlock_bdev;
1849 }
1850
1851 ret = 0;
1852 if (q->blk_trace == NULL)
1853 ret = blk_trace_setup_queue(q, bdev);
1854
1855 if (ret == 0) {
1856 if (attr == &dev_attr_act_mask)
1857 q->blk_trace->act_mask = value;
1858 else if (attr == &dev_attr_pid)
1859 q->blk_trace->pid = value;
1860 else if (attr == &dev_attr_start_lba)
1861 q->blk_trace->start_lba = value;
1862 else if (attr == &dev_attr_end_lba)
1863 q->blk_trace->end_lba = value;
1864 }
1865
1866out_unlock_bdev:
1867 mutex_unlock(&q->blk_trace_mutex);
1868out_bdput:
1869 bdput(bdev);
1870out:
1871 return ret ? ret : count;
1872}
1873
1874int blk_trace_init_sysfs(struct device *dev)
1875{
1876 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1877}
1878
1879void blk_trace_remove_sysfs(struct device *dev)
1880{
1881 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1882}
1883
1884#endif /* CONFIG_BLK_DEV_IO_TRACE */
1885
1886#ifdef CONFIG_EVENT_TRACING
1887
1888void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
1889{
1890 int i = 0;
1891
1892 if (op & REQ_PREFLUSH)
1893 rwbs[i++] = 'F';
1894
1895 switch (op & REQ_OP_MASK) {
1896 case REQ_OP_WRITE:
1897 case REQ_OP_WRITE_SAME:
1898 rwbs[i++] = 'W';
1899 break;
1900 case REQ_OP_DISCARD:
1901 rwbs[i++] = 'D';
1902 break;
1903 case REQ_OP_SECURE_ERASE:
1904 rwbs[i++] = 'D';
1905 rwbs[i++] = 'E';
1906 break;
1907 case REQ_OP_FLUSH:
1908 rwbs[i++] = 'F';
1909 break;
1910 case REQ_OP_READ:
1911 rwbs[i++] = 'R';
1912 break;
1913 default:
1914 rwbs[i++] = 'N';
1915 }
1916
1917 if (op & REQ_FUA)
1918 rwbs[i++] = 'F';
1919 if (op & REQ_RAHEAD)
1920 rwbs[i++] = 'A';
1921 if (op & REQ_SYNC)
1922 rwbs[i++] = 'S';
1923 if (op & REQ_META)
1924 rwbs[i++] = 'M';
1925
1926 rwbs[i] = '\0';
1927}
1928EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1929
1930#endif /* CONFIG_EVENT_TRACING */
1931
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/export.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
36static unsigned int blktrace_seq __read_mostly = 1;
37
38static struct trace_array *blk_tr;
39static 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
44static struct tracer_opt blk_tracer_opts[] = {
45 /* Default disable the minimalistic output */
46 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
47 { }
48};
49
50static struct tracer_flags blk_tracer_flags = {
51 .val = 0,
52 .opts = blk_tracer_opts,
53};
54
55/* Global reference count of probes */
56static atomic_t blk_probes_ref = ATOMIC_INIT(0);
57
58static void blk_register_tracepoints(void);
59static void blk_unregister_tracepoints(void);
60
61/*
62 * Send out a notify message.
63 */
64static 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());
93record_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 */
110static 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
116static 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
131void __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 /*
143 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
144 * message to the trace.
145 */
146 if (!(bt->act_mask & BLK_TC_NOTIFY))
147 return;
148
149 local_irq_save(flags);
150 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
151 va_start(args, fmt);
152 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
153 va_end(args);
154
155 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
156 local_irq_restore(flags);
157}
158EXPORT_SYMBOL_GPL(__trace_note_message);
159
160static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
161 pid_t pid)
162{
163 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
164 return 1;
165 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
166 return 1;
167 if (bt->pid && pid != bt->pid)
168 return 1;
169
170 return 0;
171}
172
173/*
174 * Data direction bit lookup
175 */
176static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
177 BLK_TC_ACT(BLK_TC_WRITE) };
178
179#define BLK_TC_RAHEAD BLK_TC_AHEAD
180
181/* The ilog2() calls fall out because they're constant */
182#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
183 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
184
185/*
186 * The worker for the various blk_add_trace*() types. Fills out a
187 * blk_io_trace structure and places it in a per-cpu subbuffer.
188 */
189static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
190 int rw, u32 what, int error, int pdu_len, void *pdu_data)
191{
192 struct task_struct *tsk = current;
193 struct ring_buffer_event *event = NULL;
194 struct ring_buffer *buffer = NULL;
195 struct blk_io_trace *t;
196 unsigned long flags = 0;
197 unsigned long *sequence;
198 pid_t pid;
199 int cpu, pc = 0;
200 bool blk_tracer = blk_tracer_enabled;
201
202 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
203 return;
204
205 what |= ddir_act[rw & WRITE];
206 what |= MASK_TC_BIT(rw, SYNC);
207 what |= MASK_TC_BIT(rw, RAHEAD);
208 what |= MASK_TC_BIT(rw, META);
209 what |= MASK_TC_BIT(rw, DISCARD);
210 what |= MASK_TC_BIT(rw, FLUSH);
211 what |= MASK_TC_BIT(rw, FUA);
212
213 pid = tsk->pid;
214 if (act_log_check(bt, what, sector, pid))
215 return;
216 cpu = raw_smp_processor_id();
217
218 if (blk_tracer) {
219 tracing_record_cmdline(current);
220
221 buffer = blk_tr->buffer;
222 pc = preempt_count();
223 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
224 sizeof(*t) + pdu_len,
225 0, pc);
226 if (!event)
227 return;
228 t = ring_buffer_event_data(event);
229 goto record_it;
230 }
231
232 /*
233 * A word about the locking here - we disable interrupts to reserve
234 * some space in the relay per-cpu buffer, to prevent an irq
235 * from coming in and stepping on our toes.
236 */
237 local_irq_save(flags);
238
239 if (unlikely(tsk->btrace_seq != blktrace_seq))
240 trace_note_tsk(bt, tsk);
241
242 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
243 if (t) {
244 sequence = per_cpu_ptr(bt->sequence, cpu);
245
246 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
247 t->sequence = ++(*sequence);
248 t->time = ktime_to_ns(ktime_get());
249record_it:
250 /*
251 * These two are not needed in ftrace as they are in the
252 * generic trace_entry, filled by tracing_generic_entry_update,
253 * but for the trace_event->bin() synthesizer benefit we do it
254 * here too.
255 */
256 t->cpu = cpu;
257 t->pid = pid;
258
259 t->sector = sector;
260 t->bytes = bytes;
261 t->action = what;
262 t->device = bt->dev;
263 t->error = error;
264 t->pdu_len = pdu_len;
265
266 if (pdu_len)
267 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
268
269 if (blk_tracer) {
270 trace_buffer_unlock_commit(buffer, event, 0, pc);
271 return;
272 }
273 }
274
275 local_irq_restore(flags);
276}
277
278static struct dentry *blk_tree_root;
279static DEFINE_MUTEX(blk_tree_mutex);
280
281static void blk_trace_free(struct blk_trace *bt)
282{
283 debugfs_remove(bt->msg_file);
284 debugfs_remove(bt->dropped_file);
285 relay_close(bt->rchan);
286 debugfs_remove(bt->dir);
287 free_percpu(bt->sequence);
288 free_percpu(bt->msg_data);
289 kfree(bt);
290}
291
292static void blk_trace_cleanup(struct blk_trace *bt)
293{
294 blk_trace_free(bt);
295 if (atomic_dec_and_test(&blk_probes_ref))
296 blk_unregister_tracepoints();
297}
298
299int blk_trace_remove(struct request_queue *q)
300{
301 struct blk_trace *bt;
302
303 bt = xchg(&q->blk_trace, NULL);
304 if (!bt)
305 return -EINVAL;
306
307 if (bt->trace_state != Blktrace_running)
308 blk_trace_cleanup(bt);
309
310 return 0;
311}
312EXPORT_SYMBOL_GPL(blk_trace_remove);
313
314static 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
325static const struct file_operations blk_dropped_fops = {
326 .owner = THIS_MODULE,
327 .open = simple_open,
328 .read = blk_dropped_read,
329 .llseek = default_llseek,
330};
331
332static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
333 size_t count, loff_t *ppos)
334{
335 char *msg;
336 struct blk_trace *bt;
337
338 if (count >= BLK_TN_MAX_MSG)
339 return -EINVAL;
340
341 msg = kmalloc(count + 1, GFP_KERNEL);
342 if (msg == NULL)
343 return -ENOMEM;
344
345 if (copy_from_user(msg, buffer, count)) {
346 kfree(msg);
347 return -EFAULT;
348 }
349
350 msg[count] = '\0';
351 bt = filp->private_data;
352 __trace_note_message(bt, "%s", msg);
353 kfree(msg);
354
355 return count;
356}
357
358static const struct file_operations blk_msg_fops = {
359 .owner = THIS_MODULE,
360 .open = simple_open,
361 .write = blk_msg_write,
362 .llseek = noop_llseek,
363};
364
365/*
366 * Keep track of how many times we encountered a full subbuffer, to aid
367 * the user space app in telling how many lost events there were.
368 */
369static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
370 void *prev_subbuf, size_t prev_padding)
371{
372 struct blk_trace *bt;
373
374 if (!relay_buf_full(buf))
375 return 1;
376
377 bt = buf->chan->private_data;
378 atomic_inc(&bt->dropped);
379 return 0;
380}
381
382static int blk_remove_buf_file_callback(struct dentry *dentry)
383{
384 debugfs_remove(dentry);
385
386 return 0;
387}
388
389static struct dentry *blk_create_buf_file_callback(const char *filename,
390 struct dentry *parent,
391 umode_t mode,
392 struct rchan_buf *buf,
393 int *is_global)
394{
395 return debugfs_create_file(filename, mode, parent, buf,
396 &relay_file_operations);
397}
398
399static struct rchan_callbacks blk_relay_callbacks = {
400 .subbuf_start = blk_subbuf_start_callback,
401 .create_buf_file = blk_create_buf_file_callback,
402 .remove_buf_file = blk_remove_buf_file_callback,
403};
404
405static void blk_trace_setup_lba(struct blk_trace *bt,
406 struct block_device *bdev)
407{
408 struct hd_struct *part = NULL;
409
410 if (bdev)
411 part = bdev->bd_part;
412
413 if (part) {
414 bt->start_lba = part->start_sect;
415 bt->end_lba = part->start_sect + part->nr_sects;
416 } else {
417 bt->start_lba = 0;
418 bt->end_lba = -1ULL;
419 }
420}
421
422/*
423 * Setup everything required to start tracing
424 */
425int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
426 struct block_device *bdev,
427 struct blk_user_trace_setup *buts)
428{
429 struct blk_trace *old_bt, *bt = NULL;
430 struct dentry *dir = NULL;
431 int ret, i;
432
433 if (!buts->buf_size || !buts->buf_nr)
434 return -EINVAL;
435
436 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
437 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
438
439 /*
440 * some device names have larger paths - convert the slashes
441 * to underscores for this to work as expected
442 */
443 for (i = 0; i < strlen(buts->name); i++)
444 if (buts->name[i] == '/')
445 buts->name[i] = '_';
446
447 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
448 if (!bt)
449 return -ENOMEM;
450
451 ret = -ENOMEM;
452 bt->sequence = alloc_percpu(unsigned long);
453 if (!bt->sequence)
454 goto err;
455
456 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
457 if (!bt->msg_data)
458 goto err;
459
460 ret = -ENOENT;
461
462 mutex_lock(&blk_tree_mutex);
463 if (!blk_tree_root) {
464 blk_tree_root = debugfs_create_dir("block", NULL);
465 if (!blk_tree_root) {
466 mutex_unlock(&blk_tree_mutex);
467 goto err;
468 }
469 }
470 mutex_unlock(&blk_tree_mutex);
471
472 dir = debugfs_create_dir(buts->name, blk_tree_root);
473
474 if (!dir)
475 goto err;
476
477 bt->dir = dir;
478 bt->dev = dev;
479 atomic_set(&bt->dropped, 0);
480
481 ret = -EIO;
482 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
483 &blk_dropped_fops);
484 if (!bt->dropped_file)
485 goto err;
486
487 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
488 if (!bt->msg_file)
489 goto err;
490
491 bt->rchan = relay_open("trace", dir, buts->buf_size,
492 buts->buf_nr, &blk_relay_callbacks, bt);
493 if (!bt->rchan)
494 goto err;
495
496 bt->act_mask = buts->act_mask;
497 if (!bt->act_mask)
498 bt->act_mask = (u16) -1;
499
500 blk_trace_setup_lba(bt, bdev);
501
502 /* overwrite with user settings */
503 if (buts->start_lba)
504 bt->start_lba = buts->start_lba;
505 if (buts->end_lba)
506 bt->end_lba = buts->end_lba;
507
508 bt->pid = buts->pid;
509 bt->trace_state = Blktrace_setup;
510
511 ret = -EBUSY;
512 old_bt = xchg(&q->blk_trace, bt);
513 if (old_bt) {
514 (void) xchg(&q->blk_trace, old_bt);
515 goto err;
516 }
517
518 if (atomic_inc_return(&blk_probes_ref) == 1)
519 blk_register_tracepoints();
520
521 return 0;
522err:
523 blk_trace_free(bt);
524 return ret;
525}
526
527int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
528 struct block_device *bdev,
529 char __user *arg)
530{
531 struct blk_user_trace_setup buts;
532 int ret;
533
534 ret = copy_from_user(&buts, arg, sizeof(buts));
535 if (ret)
536 return -EFAULT;
537
538 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
539 if (ret)
540 return ret;
541
542 if (copy_to_user(arg, &buts, sizeof(buts))) {
543 blk_trace_remove(q);
544 return -EFAULT;
545 }
546 return 0;
547}
548EXPORT_SYMBOL_GPL(blk_trace_setup);
549
550#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
551static int compat_blk_trace_setup(struct request_queue *q, char *name,
552 dev_t dev, struct block_device *bdev,
553 char __user *arg)
554{
555 struct blk_user_trace_setup buts;
556 struct compat_blk_user_trace_setup cbuts;
557 int ret;
558
559 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
560 return -EFAULT;
561
562 buts = (struct blk_user_trace_setup) {
563 .act_mask = cbuts.act_mask,
564 .buf_size = cbuts.buf_size,
565 .buf_nr = cbuts.buf_nr,
566 .start_lba = cbuts.start_lba,
567 .end_lba = cbuts.end_lba,
568 .pid = cbuts.pid,
569 };
570 memcpy(&buts.name, &cbuts.name, 32);
571
572 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
573 if (ret)
574 return ret;
575
576 if (copy_to_user(arg, &buts.name, 32)) {
577 blk_trace_remove(q);
578 return -EFAULT;
579 }
580
581 return 0;
582}
583#endif
584
585int blk_trace_startstop(struct request_queue *q, int start)
586{
587 int ret;
588 struct blk_trace *bt = q->blk_trace;
589
590 if (bt == NULL)
591 return -EINVAL;
592
593 /*
594 * For starting a trace, we can transition from a setup or stopped
595 * trace. For stopping a trace, the state must be running
596 */
597 ret = -EINVAL;
598 if (start) {
599 if (bt->trace_state == Blktrace_setup ||
600 bt->trace_state == Blktrace_stopped) {
601 blktrace_seq++;
602 smp_mb();
603 bt->trace_state = Blktrace_running;
604
605 trace_note_time(bt);
606 ret = 0;
607 }
608 } else {
609 if (bt->trace_state == Blktrace_running) {
610 bt->trace_state = Blktrace_stopped;
611 relay_flush(bt->rchan);
612 ret = 0;
613 }
614 }
615
616 return ret;
617}
618EXPORT_SYMBOL_GPL(blk_trace_startstop);
619
620/**
621 * blk_trace_ioctl: - handle the ioctls associated with tracing
622 * @bdev: the block device
623 * @cmd: the ioctl cmd
624 * @arg: the argument data, if any
625 *
626 **/
627int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
628{
629 struct request_queue *q;
630 int ret, start = 0;
631 char b[BDEVNAME_SIZE];
632
633 q = bdev_get_queue(bdev);
634 if (!q)
635 return -ENXIO;
636
637 mutex_lock(&bdev->bd_mutex);
638
639 switch (cmd) {
640 case BLKTRACESETUP:
641 bdevname(bdev, b);
642 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
643 break;
644#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
645 case BLKTRACESETUP32:
646 bdevname(bdev, b);
647 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
648 break;
649#endif
650 case BLKTRACESTART:
651 start = 1;
652 case BLKTRACESTOP:
653 ret = blk_trace_startstop(q, start);
654 break;
655 case BLKTRACETEARDOWN:
656 ret = blk_trace_remove(q);
657 break;
658 default:
659 ret = -ENOTTY;
660 break;
661 }
662
663 mutex_unlock(&bdev->bd_mutex);
664 return ret;
665}
666
667/**
668 * blk_trace_shutdown: - stop and cleanup trace structures
669 * @q: the request queue associated with the device
670 *
671 **/
672void blk_trace_shutdown(struct request_queue *q)
673{
674 if (q->blk_trace) {
675 blk_trace_startstop(q, 0);
676 blk_trace_remove(q);
677 }
678}
679
680/*
681 * blktrace probes
682 */
683
684/**
685 * blk_add_trace_rq - Add a trace for a request oriented action
686 * @q: queue the io is for
687 * @rq: the source request
688 * @what: the action
689 *
690 * Description:
691 * Records an action against a request. Will log the bio offset + size.
692 *
693 **/
694static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
695 u32 what)
696{
697 struct blk_trace *bt = q->blk_trace;
698
699 if (likely(!bt))
700 return;
701
702 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
703 what |= BLK_TC_ACT(BLK_TC_PC);
704 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rq->cmd_flags,
705 what, rq->errors, rq->cmd_len, rq->cmd);
706 } else {
707 what |= BLK_TC_ACT(BLK_TC_FS);
708 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
709 rq->cmd_flags, what, rq->errors, 0, NULL);
710 }
711}
712
713static void blk_add_trace_rq_abort(void *ignore,
714 struct request_queue *q, struct request *rq)
715{
716 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
717}
718
719static void blk_add_trace_rq_insert(void *ignore,
720 struct request_queue *q, struct request *rq)
721{
722 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
723}
724
725static void blk_add_trace_rq_issue(void *ignore,
726 struct request_queue *q, struct request *rq)
727{
728 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
729}
730
731static void blk_add_trace_rq_requeue(void *ignore,
732 struct request_queue *q,
733 struct request *rq)
734{
735 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
736}
737
738static void blk_add_trace_rq_complete(void *ignore,
739 struct request_queue *q,
740 struct request *rq)
741{
742 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
743}
744
745/**
746 * blk_add_trace_bio - Add a trace for a bio oriented action
747 * @q: queue the io is for
748 * @bio: the source bio
749 * @what: the action
750 * @error: error, if any
751 *
752 * Description:
753 * Records an action against a bio. Will log the bio offset + size.
754 *
755 **/
756static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
757 u32 what, int error)
758{
759 struct blk_trace *bt = q->blk_trace;
760
761 if (likely(!bt))
762 return;
763
764 if (!error && !bio_flagged(bio, BIO_UPTODATE))
765 error = EIO;
766
767 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
768 error, 0, NULL);
769}
770
771static void blk_add_trace_bio_bounce(void *ignore,
772 struct request_queue *q, struct bio *bio)
773{
774 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
775}
776
777static void blk_add_trace_bio_complete(void *ignore,
778 struct request_queue *q, struct bio *bio,
779 int error)
780{
781 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
782}
783
784static void blk_add_trace_bio_backmerge(void *ignore,
785 struct request_queue *q,
786 struct bio *bio)
787{
788 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
789}
790
791static void blk_add_trace_bio_frontmerge(void *ignore,
792 struct request_queue *q,
793 struct bio *bio)
794{
795 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
796}
797
798static void blk_add_trace_bio_queue(void *ignore,
799 struct request_queue *q, struct bio *bio)
800{
801 blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
802}
803
804static void blk_add_trace_getrq(void *ignore,
805 struct request_queue *q,
806 struct bio *bio, int rw)
807{
808 if (bio)
809 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
810 else {
811 struct blk_trace *bt = q->blk_trace;
812
813 if (bt)
814 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
815 }
816}
817
818
819static void blk_add_trace_sleeprq(void *ignore,
820 struct request_queue *q,
821 struct bio *bio, int rw)
822{
823 if (bio)
824 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
825 else {
826 struct blk_trace *bt = q->blk_trace;
827
828 if (bt)
829 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
830 0, 0, NULL);
831 }
832}
833
834static void blk_add_trace_plug(void *ignore, struct request_queue *q)
835{
836 struct blk_trace *bt = q->blk_trace;
837
838 if (bt)
839 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
840}
841
842static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
843 unsigned int depth, bool explicit)
844{
845 struct blk_trace *bt = q->blk_trace;
846
847 if (bt) {
848 __be64 rpdu = cpu_to_be64(depth);
849 u32 what;
850
851 if (explicit)
852 what = BLK_TA_UNPLUG_IO;
853 else
854 what = BLK_TA_UNPLUG_TIMER;
855
856 __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
857 }
858}
859
860static void blk_add_trace_split(void *ignore,
861 struct request_queue *q, struct bio *bio,
862 unsigned int pdu)
863{
864 struct blk_trace *bt = q->blk_trace;
865
866 if (bt) {
867 __be64 rpdu = cpu_to_be64(pdu);
868
869 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
870 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
871 sizeof(rpdu), &rpdu);
872 }
873}
874
875/**
876 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
877 * @ignore: trace callback data parameter (not used)
878 * @q: queue the io is for
879 * @bio: the source bio
880 * @dev: target device
881 * @from: source sector
882 *
883 * Description:
884 * Device mapper or raid target sometimes need to split a bio because
885 * it spans a stripe (or similar). Add a trace for that action.
886 *
887 **/
888static void blk_add_trace_bio_remap(void *ignore,
889 struct request_queue *q, struct bio *bio,
890 dev_t dev, sector_t from)
891{
892 struct blk_trace *bt = q->blk_trace;
893 struct blk_io_trace_remap r;
894
895 if (likely(!bt))
896 return;
897
898 r.device_from = cpu_to_be32(dev);
899 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
900 r.sector_from = cpu_to_be64(from);
901
902 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
903 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
904 sizeof(r), &r);
905}
906
907/**
908 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
909 * @ignore: trace callback data parameter (not used)
910 * @q: queue the io is for
911 * @rq: the source request
912 * @dev: target device
913 * @from: source sector
914 *
915 * Description:
916 * Device mapper remaps request to other devices.
917 * Add a trace for that action.
918 *
919 **/
920static void blk_add_trace_rq_remap(void *ignore,
921 struct request_queue *q,
922 struct request *rq, dev_t dev,
923 sector_t from)
924{
925 struct blk_trace *bt = q->blk_trace;
926 struct blk_io_trace_remap r;
927
928 if (likely(!bt))
929 return;
930
931 r.device_from = cpu_to_be32(dev);
932 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
933 r.sector_from = cpu_to_be64(from);
934
935 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
936 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
937 sizeof(r), &r);
938}
939
940/**
941 * blk_add_driver_data - Add binary message with driver-specific data
942 * @q: queue the io is for
943 * @rq: io request
944 * @data: driver-specific data
945 * @len: length of driver-specific data
946 *
947 * Description:
948 * Some drivers might want to write driver-specific data per request.
949 *
950 **/
951void blk_add_driver_data(struct request_queue *q,
952 struct request *rq,
953 void *data, size_t len)
954{
955 struct blk_trace *bt = q->blk_trace;
956
957 if (likely(!bt))
958 return;
959
960 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
961 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
962 BLK_TA_DRV_DATA, rq->errors, len, data);
963 else
964 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
965 BLK_TA_DRV_DATA, rq->errors, len, data);
966}
967EXPORT_SYMBOL_GPL(blk_add_driver_data);
968
969static void blk_register_tracepoints(void)
970{
971 int ret;
972
973 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
974 WARN_ON(ret);
975 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
976 WARN_ON(ret);
977 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
978 WARN_ON(ret);
979 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
980 WARN_ON(ret);
981 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
982 WARN_ON(ret);
983 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
984 WARN_ON(ret);
985 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
986 WARN_ON(ret);
987 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
988 WARN_ON(ret);
989 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
990 WARN_ON(ret);
991 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
992 WARN_ON(ret);
993 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
994 WARN_ON(ret);
995 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_split(blk_add_trace_split, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1006 WARN_ON(ret);
1007}
1008
1009static void blk_unregister_tracepoints(void)
1010{
1011 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1012 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1013 unregister_trace_block_split(blk_add_trace_split, NULL);
1014 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1015 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1016 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1017 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1018 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1019 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1020 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1021 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1022 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1023 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1024 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1025 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1026 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1027 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1028
1029 tracepoint_synchronize_unregister();
1030}
1031
1032/*
1033 * struct blk_io_tracer formatting routines
1034 */
1035
1036static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1037{
1038 int i = 0;
1039 int tc = t->action >> BLK_TC_SHIFT;
1040
1041 if (t->action == BLK_TN_MESSAGE) {
1042 rwbs[i++] = 'N';
1043 goto out;
1044 }
1045
1046 if (tc & BLK_TC_FLUSH)
1047 rwbs[i++] = 'F';
1048
1049 if (tc & BLK_TC_DISCARD)
1050 rwbs[i++] = 'D';
1051 else if (tc & BLK_TC_WRITE)
1052 rwbs[i++] = 'W';
1053 else if (t->bytes)
1054 rwbs[i++] = 'R';
1055 else
1056 rwbs[i++] = 'N';
1057
1058 if (tc & BLK_TC_FUA)
1059 rwbs[i++] = 'F';
1060 if (tc & BLK_TC_AHEAD)
1061 rwbs[i++] = 'A';
1062 if (tc & BLK_TC_SYNC)
1063 rwbs[i++] = 'S';
1064 if (tc & BLK_TC_META)
1065 rwbs[i++] = 'M';
1066out:
1067 rwbs[i] = '\0';
1068}
1069
1070static inline
1071const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1072{
1073 return (const struct blk_io_trace *)ent;
1074}
1075
1076static inline const void *pdu_start(const struct trace_entry *ent)
1077{
1078 return te_blk_io_trace(ent) + 1;
1079}
1080
1081static inline u32 t_action(const struct trace_entry *ent)
1082{
1083 return te_blk_io_trace(ent)->action;
1084}
1085
1086static inline u32 t_bytes(const struct trace_entry *ent)
1087{
1088 return te_blk_io_trace(ent)->bytes;
1089}
1090
1091static inline u32 t_sec(const struct trace_entry *ent)
1092{
1093 return te_blk_io_trace(ent)->bytes >> 9;
1094}
1095
1096static inline unsigned long long t_sector(const struct trace_entry *ent)
1097{
1098 return te_blk_io_trace(ent)->sector;
1099}
1100
1101static inline __u16 t_error(const struct trace_entry *ent)
1102{
1103 return te_blk_io_trace(ent)->error;
1104}
1105
1106static __u64 get_pdu_int(const struct trace_entry *ent)
1107{
1108 const __u64 *val = pdu_start(ent);
1109 return be64_to_cpu(*val);
1110}
1111
1112static void get_pdu_remap(const struct trace_entry *ent,
1113 struct blk_io_trace_remap *r)
1114{
1115 const struct blk_io_trace_remap *__r = pdu_start(ent);
1116 __u64 sector_from = __r->sector_from;
1117
1118 r->device_from = be32_to_cpu(__r->device_from);
1119 r->device_to = be32_to_cpu(__r->device_to);
1120 r->sector_from = be64_to_cpu(sector_from);
1121}
1122
1123typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1124
1125static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1126{
1127 char rwbs[RWBS_LEN];
1128 unsigned long long ts = iter->ts;
1129 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1130 unsigned secs = (unsigned long)ts;
1131 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1132
1133 fill_rwbs(rwbs, t);
1134
1135 return trace_seq_printf(&iter->seq,
1136 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1137 MAJOR(t->device), MINOR(t->device), iter->cpu,
1138 secs, nsec_rem, iter->ent->pid, act, rwbs);
1139}
1140
1141static int blk_log_action(struct trace_iterator *iter, const char *act)
1142{
1143 char rwbs[RWBS_LEN];
1144 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1145
1146 fill_rwbs(rwbs, t);
1147 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1148 MAJOR(t->device), MINOR(t->device), act, rwbs);
1149}
1150
1151static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1152{
1153 const unsigned char *pdu_buf;
1154 int pdu_len;
1155 int i, end, ret;
1156
1157 pdu_buf = pdu_start(ent);
1158 pdu_len = te_blk_io_trace(ent)->pdu_len;
1159
1160 if (!pdu_len)
1161 return 1;
1162
1163 /* find the last zero that needs to be printed */
1164 for (end = pdu_len - 1; end >= 0; end--)
1165 if (pdu_buf[end])
1166 break;
1167 end++;
1168
1169 if (!trace_seq_putc(s, '('))
1170 return 0;
1171
1172 for (i = 0; i < pdu_len; i++) {
1173
1174 ret = trace_seq_printf(s, "%s%02x",
1175 i == 0 ? "" : " ", pdu_buf[i]);
1176 if (!ret)
1177 return ret;
1178
1179 /*
1180 * stop when the rest is just zeroes and indicate so
1181 * with a ".." appended
1182 */
1183 if (i == end && end != pdu_len - 1)
1184 return trace_seq_puts(s, " ..) ");
1185 }
1186
1187 return trace_seq_puts(s, ") ");
1188}
1189
1190static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1191{
1192 char cmd[TASK_COMM_LEN];
1193
1194 trace_find_cmdline(ent->pid, cmd);
1195
1196 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1197 int ret;
1198
1199 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1200 if (!ret)
1201 return 0;
1202 ret = blk_log_dump_pdu(s, ent);
1203 if (!ret)
1204 return 0;
1205 return trace_seq_printf(s, "[%s]\n", cmd);
1206 } else {
1207 if (t_sec(ent))
1208 return trace_seq_printf(s, "%llu + %u [%s]\n",
1209 t_sector(ent), t_sec(ent), cmd);
1210 return trace_seq_printf(s, "[%s]\n", cmd);
1211 }
1212}
1213
1214static int blk_log_with_error(struct trace_seq *s,
1215 const struct trace_entry *ent)
1216{
1217 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1218 int ret;
1219
1220 ret = blk_log_dump_pdu(s, ent);
1221 if (ret)
1222 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1223 return 0;
1224 } else {
1225 if (t_sec(ent))
1226 return trace_seq_printf(s, "%llu + %u [%d]\n",
1227 t_sector(ent),
1228 t_sec(ent), t_error(ent));
1229 return trace_seq_printf(s, "%llu [%d]\n",
1230 t_sector(ent), t_error(ent));
1231 }
1232}
1233
1234static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1235{
1236 struct blk_io_trace_remap r = { .device_from = 0, };
1237
1238 get_pdu_remap(ent, &r);
1239 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1240 t_sector(ent), t_sec(ent),
1241 MAJOR(r.device_from), MINOR(r.device_from),
1242 (unsigned long long)r.sector_from);
1243}
1244
1245static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1246{
1247 char cmd[TASK_COMM_LEN];
1248
1249 trace_find_cmdline(ent->pid, cmd);
1250
1251 return trace_seq_printf(s, "[%s]\n", cmd);
1252}
1253
1254static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1255{
1256 char cmd[TASK_COMM_LEN];
1257
1258 trace_find_cmdline(ent->pid, cmd);
1259
1260 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1261}
1262
1263static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1264{
1265 char cmd[TASK_COMM_LEN];
1266
1267 trace_find_cmdline(ent->pid, cmd);
1268
1269 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1270 get_pdu_int(ent), cmd);
1271}
1272
1273static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1274{
1275 int ret;
1276 const struct blk_io_trace *t = te_blk_io_trace(ent);
1277
1278 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1279 if (ret)
1280 return trace_seq_putc(s, '\n');
1281 return ret;
1282}
1283
1284/*
1285 * struct tracer operations
1286 */
1287
1288static void blk_tracer_print_header(struct seq_file *m)
1289{
1290 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1291 return;
1292 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1293 "# | | | | | |\n");
1294}
1295
1296static void blk_tracer_start(struct trace_array *tr)
1297{
1298 blk_tracer_enabled = true;
1299}
1300
1301static int blk_tracer_init(struct trace_array *tr)
1302{
1303 blk_tr = tr;
1304 blk_tracer_start(tr);
1305 return 0;
1306}
1307
1308static void blk_tracer_stop(struct trace_array *tr)
1309{
1310 blk_tracer_enabled = false;
1311}
1312
1313static void blk_tracer_reset(struct trace_array *tr)
1314{
1315 blk_tracer_stop(tr);
1316}
1317
1318static const struct {
1319 const char *act[2];
1320 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1321} what2act[] = {
1322 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1323 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1324 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1325 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1326 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1327 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1328 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1329 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1330 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1331 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1332 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1333 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1334 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1335 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1336 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1337};
1338
1339static enum print_line_t print_one_line(struct trace_iterator *iter,
1340 bool classic)
1341{
1342 struct trace_seq *s = &iter->seq;
1343 const struct blk_io_trace *t;
1344 u16 what;
1345 int ret;
1346 bool long_act;
1347 blk_log_action_t *log_action;
1348
1349 t = te_blk_io_trace(iter->ent);
1350 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1351 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1352 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1353
1354 if (t->action == BLK_TN_MESSAGE) {
1355 ret = log_action(iter, long_act ? "message" : "m");
1356 if (ret)
1357 ret = blk_log_msg(s, iter->ent);
1358 goto out;
1359 }
1360
1361 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1362 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1363 else {
1364 ret = log_action(iter, what2act[what].act[long_act]);
1365 if (ret)
1366 ret = what2act[what].print(s, iter->ent);
1367 }
1368out:
1369 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1370}
1371
1372static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1373 int flags, struct trace_event *event)
1374{
1375 return print_one_line(iter, false);
1376}
1377
1378static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1379{
1380 struct trace_seq *s = &iter->seq;
1381 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1382 const int offset = offsetof(struct blk_io_trace, sector);
1383 struct blk_io_trace old = {
1384 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1385 .time = iter->ts,
1386 };
1387
1388 if (!trace_seq_putmem(s, &old, offset))
1389 return 0;
1390 return trace_seq_putmem(s, &t->sector,
1391 sizeof(old) - offset + t->pdu_len);
1392}
1393
1394static enum print_line_t
1395blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1396 struct trace_event *event)
1397{
1398 return blk_trace_synthesize_old_trace(iter) ?
1399 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1400}
1401
1402static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1403{
1404 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1405 return TRACE_TYPE_UNHANDLED;
1406
1407 return print_one_line(iter, true);
1408}
1409
1410static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1411{
1412 /* don't output context-info for blk_classic output */
1413 if (bit == TRACE_BLK_OPT_CLASSIC) {
1414 if (set)
1415 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1416 else
1417 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1418 }
1419 return 0;
1420}
1421
1422static struct tracer blk_tracer __read_mostly = {
1423 .name = "blk",
1424 .init = blk_tracer_init,
1425 .reset = blk_tracer_reset,
1426 .start = blk_tracer_start,
1427 .stop = blk_tracer_stop,
1428 .print_header = blk_tracer_print_header,
1429 .print_line = blk_tracer_print_line,
1430 .flags = &blk_tracer_flags,
1431 .set_flag = blk_tracer_set_flag,
1432};
1433
1434static struct trace_event_functions trace_blk_event_funcs = {
1435 .trace = blk_trace_event_print,
1436 .binary = blk_trace_event_print_binary,
1437};
1438
1439static struct trace_event trace_blk_event = {
1440 .type = TRACE_BLK,
1441 .funcs = &trace_blk_event_funcs,
1442};
1443
1444static int __init init_blk_tracer(void)
1445{
1446 if (!register_ftrace_event(&trace_blk_event)) {
1447 pr_warning("Warning: could not register block events\n");
1448 return 1;
1449 }
1450
1451 if (register_tracer(&blk_tracer) != 0) {
1452 pr_warning("Warning: could not register the block tracer\n");
1453 unregister_ftrace_event(&trace_blk_event);
1454 return 1;
1455 }
1456
1457 return 0;
1458}
1459
1460device_initcall(init_blk_tracer);
1461
1462static int blk_trace_remove_queue(struct request_queue *q)
1463{
1464 struct blk_trace *bt;
1465
1466 bt = xchg(&q->blk_trace, NULL);
1467 if (bt == NULL)
1468 return -EINVAL;
1469
1470 if (atomic_dec_and_test(&blk_probes_ref))
1471 blk_unregister_tracepoints();
1472
1473 blk_trace_free(bt);
1474 return 0;
1475}
1476
1477/*
1478 * Setup everything required to start tracing
1479 */
1480static int blk_trace_setup_queue(struct request_queue *q,
1481 struct block_device *bdev)
1482{
1483 struct blk_trace *old_bt, *bt = NULL;
1484 int ret = -ENOMEM;
1485
1486 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1487 if (!bt)
1488 return -ENOMEM;
1489
1490 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1491 if (!bt->msg_data)
1492 goto free_bt;
1493
1494 bt->dev = bdev->bd_dev;
1495 bt->act_mask = (u16)-1;
1496
1497 blk_trace_setup_lba(bt, bdev);
1498
1499 old_bt = xchg(&q->blk_trace, bt);
1500 if (old_bt != NULL) {
1501 (void)xchg(&q->blk_trace, old_bt);
1502 ret = -EBUSY;
1503 goto free_bt;
1504 }
1505
1506 if (atomic_inc_return(&blk_probes_ref) == 1)
1507 blk_register_tracepoints();
1508 return 0;
1509
1510free_bt:
1511 blk_trace_free(bt);
1512 return ret;
1513}
1514
1515/*
1516 * sysfs interface to enable and configure tracing
1517 */
1518
1519static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1520 struct device_attribute *attr,
1521 char *buf);
1522static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1523 struct device_attribute *attr,
1524 const char *buf, size_t count);
1525#define BLK_TRACE_DEVICE_ATTR(_name) \
1526 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1527 sysfs_blk_trace_attr_show, \
1528 sysfs_blk_trace_attr_store)
1529
1530static BLK_TRACE_DEVICE_ATTR(enable);
1531static BLK_TRACE_DEVICE_ATTR(act_mask);
1532static BLK_TRACE_DEVICE_ATTR(pid);
1533static BLK_TRACE_DEVICE_ATTR(start_lba);
1534static BLK_TRACE_DEVICE_ATTR(end_lba);
1535
1536static struct attribute *blk_trace_attrs[] = {
1537 &dev_attr_enable.attr,
1538 &dev_attr_act_mask.attr,
1539 &dev_attr_pid.attr,
1540 &dev_attr_start_lba.attr,
1541 &dev_attr_end_lba.attr,
1542 NULL
1543};
1544
1545struct attribute_group blk_trace_attr_group = {
1546 .name = "trace",
1547 .attrs = blk_trace_attrs,
1548};
1549
1550static const struct {
1551 int mask;
1552 const char *str;
1553} mask_maps[] = {
1554 { BLK_TC_READ, "read" },
1555 { BLK_TC_WRITE, "write" },
1556 { BLK_TC_FLUSH, "flush" },
1557 { BLK_TC_SYNC, "sync" },
1558 { BLK_TC_QUEUE, "queue" },
1559 { BLK_TC_REQUEUE, "requeue" },
1560 { BLK_TC_ISSUE, "issue" },
1561 { BLK_TC_COMPLETE, "complete" },
1562 { BLK_TC_FS, "fs" },
1563 { BLK_TC_PC, "pc" },
1564 { BLK_TC_AHEAD, "ahead" },
1565 { BLK_TC_META, "meta" },
1566 { BLK_TC_DISCARD, "discard" },
1567 { BLK_TC_DRV_DATA, "drv_data" },
1568 { BLK_TC_FUA, "fua" },
1569};
1570
1571static int blk_trace_str2mask(const char *str)
1572{
1573 int i;
1574 int mask = 0;
1575 char *buf, *s, *token;
1576
1577 buf = kstrdup(str, GFP_KERNEL);
1578 if (buf == NULL)
1579 return -ENOMEM;
1580 s = strstrip(buf);
1581
1582 while (1) {
1583 token = strsep(&s, ",");
1584 if (token == NULL)
1585 break;
1586
1587 if (*token == '\0')
1588 continue;
1589
1590 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1591 if (strcasecmp(token, mask_maps[i].str) == 0) {
1592 mask |= mask_maps[i].mask;
1593 break;
1594 }
1595 }
1596 if (i == ARRAY_SIZE(mask_maps)) {
1597 mask = -EINVAL;
1598 break;
1599 }
1600 }
1601 kfree(buf);
1602
1603 return mask;
1604}
1605
1606static ssize_t blk_trace_mask2str(char *buf, int mask)
1607{
1608 int i;
1609 char *p = buf;
1610
1611 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1612 if (mask & mask_maps[i].mask) {
1613 p += sprintf(p, "%s%s",
1614 (p == buf) ? "" : ",", mask_maps[i].str);
1615 }
1616 }
1617 *p++ = '\n';
1618
1619 return p - buf;
1620}
1621
1622static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1623{
1624 if (bdev->bd_disk == NULL)
1625 return NULL;
1626
1627 return bdev_get_queue(bdev);
1628}
1629
1630static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1631 struct device_attribute *attr,
1632 char *buf)
1633{
1634 struct hd_struct *p = dev_to_part(dev);
1635 struct request_queue *q;
1636 struct block_device *bdev;
1637 ssize_t ret = -ENXIO;
1638
1639 bdev = bdget(part_devt(p));
1640 if (bdev == NULL)
1641 goto out;
1642
1643 q = blk_trace_get_queue(bdev);
1644 if (q == NULL)
1645 goto out_bdput;
1646
1647 mutex_lock(&bdev->bd_mutex);
1648
1649 if (attr == &dev_attr_enable) {
1650 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1651 goto out_unlock_bdev;
1652 }
1653
1654 if (q->blk_trace == NULL)
1655 ret = sprintf(buf, "disabled\n");
1656 else if (attr == &dev_attr_act_mask)
1657 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1658 else if (attr == &dev_attr_pid)
1659 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1660 else if (attr == &dev_attr_start_lba)
1661 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1662 else if (attr == &dev_attr_end_lba)
1663 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1664
1665out_unlock_bdev:
1666 mutex_unlock(&bdev->bd_mutex);
1667out_bdput:
1668 bdput(bdev);
1669out:
1670 return ret;
1671}
1672
1673static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1674 struct device_attribute *attr,
1675 const char *buf, size_t count)
1676{
1677 struct block_device *bdev;
1678 struct request_queue *q;
1679 struct hd_struct *p;
1680 u64 value;
1681 ssize_t ret = -EINVAL;
1682
1683 if (count == 0)
1684 goto out;
1685
1686 if (attr == &dev_attr_act_mask) {
1687 if (sscanf(buf, "%llx", &value) != 1) {
1688 /* Assume it is a list of trace category names */
1689 ret = blk_trace_str2mask(buf);
1690 if (ret < 0)
1691 goto out;
1692 value = ret;
1693 }
1694 } else if (sscanf(buf, "%llu", &value) != 1)
1695 goto out;
1696
1697 ret = -ENXIO;
1698
1699 p = dev_to_part(dev);
1700 bdev = bdget(part_devt(p));
1701 if (bdev == NULL)
1702 goto out;
1703
1704 q = blk_trace_get_queue(bdev);
1705 if (q == NULL)
1706 goto out_bdput;
1707
1708 mutex_lock(&bdev->bd_mutex);
1709
1710 if (attr == &dev_attr_enable) {
1711 if (value)
1712 ret = blk_trace_setup_queue(q, bdev);
1713 else
1714 ret = blk_trace_remove_queue(q);
1715 goto out_unlock_bdev;
1716 }
1717
1718 ret = 0;
1719 if (q->blk_trace == NULL)
1720 ret = blk_trace_setup_queue(q, bdev);
1721
1722 if (ret == 0) {
1723 if (attr == &dev_attr_act_mask)
1724 q->blk_trace->act_mask = value;
1725 else if (attr == &dev_attr_pid)
1726 q->blk_trace->pid = value;
1727 else if (attr == &dev_attr_start_lba)
1728 q->blk_trace->start_lba = value;
1729 else if (attr == &dev_attr_end_lba)
1730 q->blk_trace->end_lba = value;
1731 }
1732
1733out_unlock_bdev:
1734 mutex_unlock(&bdev->bd_mutex);
1735out_bdput:
1736 bdput(bdev);
1737out:
1738 return ret ? ret : count;
1739}
1740
1741int blk_trace_init_sysfs(struct device *dev)
1742{
1743 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1744}
1745
1746void blk_trace_remove_sysfs(struct device *dev)
1747{
1748 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1749}
1750
1751#endif /* CONFIG_BLK_DEV_IO_TRACE */
1752
1753#ifdef CONFIG_EVENT_TRACING
1754
1755void blk_dump_cmd(char *buf, struct request *rq)
1756{
1757 int i, end;
1758 int len = rq->cmd_len;
1759 unsigned char *cmd = rq->cmd;
1760
1761 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1762 buf[0] = '\0';
1763 return;
1764 }
1765
1766 for (end = len - 1; end >= 0; end--)
1767 if (cmd[end])
1768 break;
1769 end++;
1770
1771 for (i = 0; i < len; i++) {
1772 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1773 if (i == end && end != len - 1) {
1774 sprintf(buf, " ..");
1775 break;
1776 }
1777 }
1778}
1779
1780void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1781{
1782 int i = 0;
1783
1784 if (rw & REQ_FLUSH)
1785 rwbs[i++] = 'F';
1786
1787 if (rw & WRITE)
1788 rwbs[i++] = 'W';
1789 else if (rw & REQ_DISCARD)
1790 rwbs[i++] = 'D';
1791 else if (bytes)
1792 rwbs[i++] = 'R';
1793 else
1794 rwbs[i++] = 'N';
1795
1796 if (rw & REQ_FUA)
1797 rwbs[i++] = 'F';
1798 if (rw & REQ_RAHEAD)
1799 rwbs[i++] = 'A';
1800 if (rw & REQ_SYNC)
1801 rwbs[i++] = 'S';
1802 if (rw & REQ_META)
1803 rwbs[i++] = 'M';
1804 if (rw & REQ_SECURE)
1805 rwbs[i++] = 'E';
1806
1807 rwbs[i] = '\0';
1808}
1809
1810#endif /* CONFIG_EVENT_TRACING */
1811