Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
4 : *
5 : */
6 :
7 : #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8 :
9 : #include <linux/kernel.h>
10 : #include <linux/blkdev.h>
11 : #include <linux/blktrace_api.h>
12 : #include <linux/percpu.h>
13 : #include <linux/init.h>
14 : #include <linux/mutex.h>
15 : #include <linux/slab.h>
16 : #include <linux/debugfs.h>
17 : #include <linux/export.h>
18 : #include <linux/time.h>
19 : #include <linux/uaccess.h>
20 : #include <linux/list.h>
21 : #include <linux/blk-cgroup.h>
22 :
23 : #include "../../block/blk.h"
24 :
25 : #include <trace/events/block.h>
26 :
27 : #include "trace_output.h"
28 :
29 : #ifdef CONFIG_BLK_DEV_IO_TRACE
30 :
31 : static unsigned int blktrace_seq __read_mostly = 1;
32 :
33 : static struct trace_array *blk_tr;
34 : static bool blk_tracer_enabled __read_mostly;
35 :
36 : static LIST_HEAD(running_trace_list);
37 : static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
38 :
39 : /* Select an alternative, minimalistic output than the original one */
40 : #define TRACE_BLK_OPT_CLASSIC 0x1
41 : #define TRACE_BLK_OPT_CGROUP 0x2
42 : #define TRACE_BLK_OPT_CGNAME 0x4
43 :
44 : static struct tracer_opt blk_tracer_opts[] = {
45 : /* Default disable the minimalistic output */
46 : { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
47 : #ifdef CONFIG_BLK_CGROUP
48 : { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
49 : { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
50 : #endif
51 : { }
52 : };
53 :
54 : static struct tracer_flags blk_tracer_flags = {
55 : .val = 0,
56 : .opts = blk_tracer_opts,
57 : };
58 :
59 : /* Global reference count of probes */
60 : static DEFINE_MUTEX(blk_probe_mutex);
61 : static int blk_probes_ref;
62 :
63 : static void blk_register_tracepoints(void);
64 : static void blk_unregister_tracepoints(void);
65 :
66 : /*
67 : * Send out a notify message.
68 : */
69 : static void trace_note(struct blk_trace *bt, pid_t pid, int action,
70 : const void *data, size_t len, u64 cgid)
71 : {
72 : struct blk_io_trace *t;
73 : struct ring_buffer_event *event = NULL;
74 : struct trace_buffer *buffer = NULL;
75 : unsigned int trace_ctx = 0;
76 : int cpu = smp_processor_id();
77 : bool blk_tracer = blk_tracer_enabled;
78 : ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
79 :
80 : if (blk_tracer) {
81 : buffer = blk_tr->array_buffer.buffer;
82 : trace_ctx = tracing_gen_ctx_flags(0);
83 : event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
84 : sizeof(*t) + len + cgid_len,
85 : trace_ctx);
86 : if (!event)
87 : return;
88 : t = ring_buffer_event_data(event);
89 : goto record_it;
90 : }
91 :
92 : if (!bt->rchan)
93 : return;
94 :
95 : t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len);
96 : if (t) {
97 : t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
98 : t->time = ktime_to_ns(ktime_get());
99 : record_it:
100 : t->device = bt->dev;
101 : t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
102 : t->pid = pid;
103 : t->cpu = cpu;
104 : t->pdu_len = len + cgid_len;
105 : if (cgid_len)
106 : memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
107 : memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
108 :
109 : if (blk_tracer)
110 : trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
111 : }
112 : }
113 :
114 : /*
115 : * Send out a notify for this process, if we haven't done so since a trace
116 : * started
117 : */
118 : static void trace_note_tsk(struct task_struct *tsk)
119 : {
120 : unsigned long flags;
121 : struct blk_trace *bt;
122 :
123 : tsk->btrace_seq = blktrace_seq;
124 : spin_lock_irqsave(&running_trace_lock, flags);
125 : list_for_each_entry(bt, &running_trace_list, running_list) {
126 : trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
127 : sizeof(tsk->comm), 0);
128 : }
129 : spin_unlock_irqrestore(&running_trace_lock, flags);
130 : }
131 :
132 : static void trace_note_time(struct blk_trace *bt)
133 : {
134 : struct timespec64 now;
135 : unsigned long flags;
136 : u32 words[2];
137 :
138 : /* need to check user space to see if this breaks in y2038 or y2106 */
139 : ktime_get_real_ts64(&now);
140 : words[0] = (u32)now.tv_sec;
141 : words[1] = now.tv_nsec;
142 :
143 : local_irq_save(flags);
144 : trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), 0);
145 : local_irq_restore(flags);
146 : }
147 :
148 : void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
149 : const char *fmt, ...)
150 : {
151 : int n;
152 : va_list args;
153 : unsigned long flags;
154 : char *buf;
155 :
156 : if (unlikely(bt->trace_state != Blktrace_running &&
157 : !blk_tracer_enabled))
158 : return;
159 :
160 : /*
161 : * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
162 : * message to the trace.
163 : */
164 : if (!(bt->act_mask & BLK_TC_NOTIFY))
165 : return;
166 :
167 : local_irq_save(flags);
168 : buf = this_cpu_ptr(bt->msg_data);
169 : va_start(args, fmt);
170 : n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
171 : va_end(args);
172 :
173 : if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
174 : blkcg = NULL;
175 : #ifdef CONFIG_BLK_CGROUP
176 : trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n,
177 : blkcg ? cgroup_id(blkcg->css.cgroup) : 1);
178 : #else
179 : trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n, 0);
180 : #endif
181 : local_irq_restore(flags);
182 : }
183 : EXPORT_SYMBOL_GPL(__trace_note_message);
184 :
185 : static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
186 : pid_t pid)
187 : {
188 : if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
189 : return 1;
190 : if (sector && (sector < bt->start_lba || sector > bt->end_lba))
191 : return 1;
192 : if (bt->pid && pid != bt->pid)
193 : return 1;
194 :
195 : return 0;
196 : }
197 :
198 : /*
199 : * Data direction bit lookup
200 : */
201 : static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
202 : BLK_TC_ACT(BLK_TC_WRITE) };
203 :
204 : #define BLK_TC_RAHEAD BLK_TC_AHEAD
205 : #define BLK_TC_PREFLUSH BLK_TC_FLUSH
206 :
207 : /* The ilog2() calls fall out because they're constant */
208 : #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
209 : (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
210 :
211 : /*
212 : * The worker for the various blk_add_trace*() types. Fills out a
213 : * blk_io_trace structure and places it in a per-cpu subbuffer.
214 : */
215 : static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
216 : int op, int op_flags, u32 what, int error, int pdu_len,
217 : void *pdu_data, u64 cgid)
218 : {
219 : struct task_struct *tsk = current;
220 : struct ring_buffer_event *event = NULL;
221 : struct trace_buffer *buffer = NULL;
222 : struct blk_io_trace *t;
223 : unsigned long flags = 0;
224 : unsigned long *sequence;
225 : unsigned int trace_ctx = 0;
226 : pid_t pid;
227 : int cpu;
228 : bool blk_tracer = blk_tracer_enabled;
229 : ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
230 :
231 : if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
232 : return;
233 :
234 : what |= ddir_act[op_is_write(op) ? WRITE : READ];
235 : what |= MASK_TC_BIT(op_flags, SYNC);
236 : what |= MASK_TC_BIT(op_flags, RAHEAD);
237 : what |= MASK_TC_BIT(op_flags, META);
238 : what |= MASK_TC_BIT(op_flags, PREFLUSH);
239 : what |= MASK_TC_BIT(op_flags, FUA);
240 : if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
241 : what |= BLK_TC_ACT(BLK_TC_DISCARD);
242 : if (op == REQ_OP_FLUSH)
243 : what |= BLK_TC_ACT(BLK_TC_FLUSH);
244 : if (cgid)
245 : what |= __BLK_TA_CGROUP;
246 :
247 : pid = tsk->pid;
248 : if (act_log_check(bt, what, sector, pid))
249 : return;
250 : cpu = raw_smp_processor_id();
251 :
252 : if (blk_tracer) {
253 : tracing_record_cmdline(current);
254 :
255 : buffer = blk_tr->array_buffer.buffer;
256 : trace_ctx = tracing_gen_ctx_flags(0);
257 : event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
258 : sizeof(*t) + pdu_len + cgid_len,
259 : trace_ctx);
260 : if (!event)
261 : return;
262 : t = ring_buffer_event_data(event);
263 : goto record_it;
264 : }
265 :
266 : if (unlikely(tsk->btrace_seq != blktrace_seq))
267 : trace_note_tsk(tsk);
268 :
269 : /*
270 : * A word about the locking here - we disable interrupts to reserve
271 : * some space in the relay per-cpu buffer, to prevent an irq
272 : * from coming in and stepping on our toes.
273 : */
274 : local_irq_save(flags);
275 : t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
276 : if (t) {
277 : sequence = per_cpu_ptr(bt->sequence, cpu);
278 :
279 : t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
280 : t->sequence = ++(*sequence);
281 : t->time = ktime_to_ns(ktime_get());
282 : record_it:
283 : /*
284 : * These two are not needed in ftrace as they are in the
285 : * generic trace_entry, filled by tracing_generic_entry_update,
286 : * but for the trace_event->bin() synthesizer benefit we do it
287 : * here too.
288 : */
289 : t->cpu = cpu;
290 : t->pid = pid;
291 :
292 : t->sector = sector;
293 : t->bytes = bytes;
294 : t->action = what;
295 : t->device = bt->dev;
296 : t->error = error;
297 : t->pdu_len = pdu_len + cgid_len;
298 :
299 : if (cgid_len)
300 : memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
301 : if (pdu_len)
302 : memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
303 :
304 : if (blk_tracer) {
305 : trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
306 : return;
307 : }
308 : }
309 :
310 : local_irq_restore(flags);
311 : }
312 :
313 : static void blk_trace_free(struct blk_trace *bt)
314 : {
315 : relay_close(bt->rchan);
316 : debugfs_remove(bt->dir);
317 : free_percpu(bt->sequence);
318 : free_percpu(bt->msg_data);
319 : kfree(bt);
320 : }
321 :
322 : static void get_probe_ref(void)
323 : {
324 : mutex_lock(&blk_probe_mutex);
325 : if (++blk_probes_ref == 1)
326 : blk_register_tracepoints();
327 : mutex_unlock(&blk_probe_mutex);
328 : }
329 :
330 : static void put_probe_ref(void)
331 : {
332 : mutex_lock(&blk_probe_mutex);
333 : if (!--blk_probes_ref)
334 : blk_unregister_tracepoints();
335 : mutex_unlock(&blk_probe_mutex);
336 : }
337 :
338 : static void blk_trace_cleanup(struct blk_trace *bt)
339 : {
340 : synchronize_rcu();
341 : blk_trace_free(bt);
342 : put_probe_ref();
343 : }
344 :
345 : static int __blk_trace_remove(struct request_queue *q)
346 : {
347 : struct blk_trace *bt;
348 :
349 : bt = rcu_replace_pointer(q->blk_trace, NULL,
350 : lockdep_is_held(&q->debugfs_mutex));
351 : if (!bt)
352 : return -EINVAL;
353 :
354 : if (bt->trace_state != Blktrace_running)
355 : blk_trace_cleanup(bt);
356 :
357 : return 0;
358 : }
359 :
360 : int blk_trace_remove(struct request_queue *q)
361 : {
362 : int ret;
363 :
364 : mutex_lock(&q->debugfs_mutex);
365 : ret = __blk_trace_remove(q);
366 : mutex_unlock(&q->debugfs_mutex);
367 :
368 : return ret;
369 : }
370 : EXPORT_SYMBOL_GPL(blk_trace_remove);
371 :
372 : static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
373 : size_t count, loff_t *ppos)
374 : {
375 : struct blk_trace *bt = filp->private_data;
376 : char buf[16];
377 :
378 : snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
379 :
380 : return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
381 : }
382 :
383 : static const struct file_operations blk_dropped_fops = {
384 : .owner = THIS_MODULE,
385 : .open = simple_open,
386 : .read = blk_dropped_read,
387 : .llseek = default_llseek,
388 : };
389 :
390 : static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
391 : size_t count, loff_t *ppos)
392 : {
393 : char *msg;
394 : struct blk_trace *bt;
395 :
396 : if (count >= BLK_TN_MAX_MSG)
397 : return -EINVAL;
398 :
399 : msg = memdup_user_nul(buffer, count);
400 : if (IS_ERR(msg))
401 : return PTR_ERR(msg);
402 :
403 : bt = filp->private_data;
404 : __trace_note_message(bt, NULL, "%s", msg);
405 : kfree(msg);
406 :
407 : return count;
408 : }
409 :
410 : static const struct file_operations blk_msg_fops = {
411 : .owner = THIS_MODULE,
412 : .open = simple_open,
413 : .write = blk_msg_write,
414 : .llseek = noop_llseek,
415 : };
416 :
417 : /*
418 : * Keep track of how many times we encountered a full subbuffer, to aid
419 : * the user space app in telling how many lost events there were.
420 : */
421 : static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
422 : void *prev_subbuf, size_t prev_padding)
423 : {
424 : struct blk_trace *bt;
425 :
426 : if (!relay_buf_full(buf))
427 : return 1;
428 :
429 : bt = buf->chan->private_data;
430 : atomic_inc(&bt->dropped);
431 : return 0;
432 : }
433 :
434 : static int blk_remove_buf_file_callback(struct dentry *dentry)
435 : {
436 : debugfs_remove(dentry);
437 :
438 : return 0;
439 : }
440 :
441 : static struct dentry *blk_create_buf_file_callback(const char *filename,
442 : struct dentry *parent,
443 : umode_t mode,
444 : struct rchan_buf *buf,
445 : int *is_global)
446 : {
447 : return debugfs_create_file(filename, mode, parent, buf,
448 : &relay_file_operations);
449 : }
450 :
451 : static const struct rchan_callbacks blk_relay_callbacks = {
452 : .subbuf_start = blk_subbuf_start_callback,
453 : .create_buf_file = blk_create_buf_file_callback,
454 : .remove_buf_file = blk_remove_buf_file_callback,
455 : };
456 :
457 : static void blk_trace_setup_lba(struct blk_trace *bt,
458 : struct block_device *bdev)
459 : {
460 : if (bdev) {
461 : bt->start_lba = bdev->bd_start_sect;
462 : bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev);
463 : } else {
464 : bt->start_lba = 0;
465 : bt->end_lba = -1ULL;
466 : }
467 : }
468 :
469 : /*
470 : * Setup everything required to start tracing
471 : */
472 : static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
473 : struct block_device *bdev,
474 : struct blk_user_trace_setup *buts)
475 : {
476 : struct blk_trace *bt = NULL;
477 : struct dentry *dir = NULL;
478 : int ret;
479 :
480 : lockdep_assert_held(&q->debugfs_mutex);
481 :
482 : if (!buts->buf_size || !buts->buf_nr)
483 : return -EINVAL;
484 :
485 : strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
486 : buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
487 :
488 : /*
489 : * some device names have larger paths - convert the slashes
490 : * to underscores for this to work as expected
491 : */
492 : strreplace(buts->name, '/', '_');
493 :
494 : /*
495 : * bdev can be NULL, as with scsi-generic, this is a helpful as
496 : * we can be.
497 : */
498 : if (rcu_dereference_protected(q->blk_trace,
499 : lockdep_is_held(&q->debugfs_mutex))) {
500 : pr_warn("Concurrent blktraces are not allowed on %s\n",
501 : buts->name);
502 : return -EBUSY;
503 : }
504 :
505 : bt = kzalloc(sizeof(*bt), GFP_KERNEL);
506 : if (!bt)
507 : return -ENOMEM;
508 :
509 : ret = -ENOMEM;
510 : bt->sequence = alloc_percpu(unsigned long);
511 : if (!bt->sequence)
512 : goto err;
513 :
514 : bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
515 : if (!bt->msg_data)
516 : goto err;
517 :
518 : /*
519 : * When tracing the whole disk reuse the existing debugfs directory
520 : * created by the block layer on init. For partitions block devices,
521 : * and scsi-generic block devices we create a temporary new debugfs
522 : * directory that will be removed once the trace ends.
523 : */
524 : if (bdev && !bdev_is_partition(bdev))
525 : dir = q->debugfs_dir;
526 : else
527 : bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
528 :
529 : /*
530 : * As blktrace relies on debugfs for its interface the debugfs directory
531 : * is required, contrary to the usual mantra of not checking for debugfs
532 : * files or directories.
533 : */
534 : if (IS_ERR_OR_NULL(dir)) {
535 : pr_warn("debugfs_dir not present for %s so skipping\n",
536 : buts->name);
537 : ret = -ENOENT;
538 : goto err;
539 : }
540 :
541 : bt->dev = dev;
542 : atomic_set(&bt->dropped, 0);
543 : INIT_LIST_HEAD(&bt->running_list);
544 :
545 : ret = -EIO;
546 : debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
547 : debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
548 :
549 : bt->rchan = relay_open("trace", dir, buts->buf_size,
550 : buts->buf_nr, &blk_relay_callbacks, bt);
551 : if (!bt->rchan)
552 : goto err;
553 :
554 : bt->act_mask = buts->act_mask;
555 : if (!bt->act_mask)
556 : bt->act_mask = (u16) -1;
557 :
558 : blk_trace_setup_lba(bt, bdev);
559 :
560 : /* overwrite with user settings */
561 : if (buts->start_lba)
562 : bt->start_lba = buts->start_lba;
563 : if (buts->end_lba)
564 : bt->end_lba = buts->end_lba;
565 :
566 : bt->pid = buts->pid;
567 : bt->trace_state = Blktrace_setup;
568 :
569 : rcu_assign_pointer(q->blk_trace, bt);
570 : get_probe_ref();
571 :
572 : ret = 0;
573 : err:
574 : if (ret)
575 : blk_trace_free(bt);
576 : return ret;
577 : }
578 :
579 : static 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 :
600 : int 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->debugfs_mutex);
607 : ret = __blk_trace_setup(q, name, dev, bdev, arg);
608 : mutex_unlock(&q->debugfs_mutex);
609 :
610 : return ret;
611 : }
612 : EXPORT_SYMBOL_GPL(blk_trace_setup);
613 :
614 : #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
615 : static 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 :
648 : static int __blk_trace_startstop(struct request_queue *q, int start)
649 : {
650 : int ret;
651 : struct blk_trace *bt;
652 :
653 : bt = rcu_dereference_protected(q->blk_trace,
654 : lockdep_is_held(&q->debugfs_mutex));
655 : if (bt == NULL)
656 : return -EINVAL;
657 :
658 : /*
659 : * For starting a trace, we can transition from a setup or stopped
660 : * trace. For stopping a trace, the state must be running
661 : */
662 : ret = -EINVAL;
663 : if (start) {
664 : if (bt->trace_state == Blktrace_setup ||
665 : bt->trace_state == Blktrace_stopped) {
666 : blktrace_seq++;
667 : smp_mb();
668 : bt->trace_state = Blktrace_running;
669 : spin_lock_irq(&running_trace_lock);
670 : list_add(&bt->running_list, &running_trace_list);
671 : spin_unlock_irq(&running_trace_lock);
672 :
673 : trace_note_time(bt);
674 : ret = 0;
675 : }
676 : } else {
677 : if (bt->trace_state == Blktrace_running) {
678 : bt->trace_state = Blktrace_stopped;
679 : spin_lock_irq(&running_trace_lock);
680 : list_del_init(&bt->running_list);
681 : spin_unlock_irq(&running_trace_lock);
682 : relay_flush(bt->rchan);
683 : ret = 0;
684 : }
685 : }
686 :
687 : return ret;
688 : }
689 :
690 : int blk_trace_startstop(struct request_queue *q, int start)
691 : {
692 : int ret;
693 :
694 : mutex_lock(&q->debugfs_mutex);
695 : ret = __blk_trace_startstop(q, start);
696 : mutex_unlock(&q->debugfs_mutex);
697 :
698 : return ret;
699 : }
700 : EXPORT_SYMBOL_GPL(blk_trace_startstop);
701 :
702 : /*
703 : * When reading or writing the blktrace sysfs files, the references to the
704 : * opened sysfs or device files should prevent the underlying block device
705 : * from being removed. So no further delete protection is really needed.
706 : */
707 :
708 : /**
709 : * blk_trace_ioctl: - handle the ioctls associated with tracing
710 : * @bdev: the block device
711 : * @cmd: the ioctl cmd
712 : * @arg: the argument data, if any
713 : *
714 : **/
715 : int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
716 : {
717 : struct request_queue *q;
718 : int ret, start = 0;
719 : char b[BDEVNAME_SIZE];
720 :
721 : q = bdev_get_queue(bdev);
722 : if (!q)
723 : return -ENXIO;
724 :
725 : mutex_lock(&q->debugfs_mutex);
726 :
727 : switch (cmd) {
728 : case BLKTRACESETUP:
729 : bdevname(bdev, b);
730 : ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
731 : break;
732 : #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
733 : case BLKTRACESETUP32:
734 : bdevname(bdev, b);
735 : ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
736 : break;
737 : #endif
738 : case BLKTRACESTART:
739 : start = 1;
740 : fallthrough;
741 : case BLKTRACESTOP:
742 : ret = __blk_trace_startstop(q, start);
743 : break;
744 : case BLKTRACETEARDOWN:
745 : ret = __blk_trace_remove(q);
746 : break;
747 : default:
748 : ret = -ENOTTY;
749 : break;
750 : }
751 :
752 : mutex_unlock(&q->debugfs_mutex);
753 : return ret;
754 : }
755 :
756 : /**
757 : * blk_trace_shutdown: - stop and cleanup trace structures
758 : * @q: the request queue associated with the device
759 : *
760 : **/
761 : void blk_trace_shutdown(struct request_queue *q)
762 : {
763 : mutex_lock(&q->debugfs_mutex);
764 : if (rcu_dereference_protected(q->blk_trace,
765 : lockdep_is_held(&q->debugfs_mutex))) {
766 : __blk_trace_startstop(q, 0);
767 : __blk_trace_remove(q);
768 : }
769 :
770 : mutex_unlock(&q->debugfs_mutex);
771 : }
772 :
773 : #ifdef CONFIG_BLK_CGROUP
774 : static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
775 : {
776 : struct blk_trace *bt;
777 :
778 : /* We don't use the 'bt' value here except as an optimization... */
779 : bt = rcu_dereference_protected(q->blk_trace, 1);
780 : if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
781 : return 0;
782 :
783 : if (!bio->bi_blkg)
784 : return 0;
785 : return cgroup_id(bio_blkcg(bio)->css.cgroup);
786 : }
787 : #else
788 : static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
789 : {
790 : return 0;
791 : }
792 : #endif
793 :
794 : static u64
795 : blk_trace_request_get_cgid(struct request *rq)
796 : {
797 : if (!rq->bio)
798 : return 0;
799 : /* Use the first bio */
800 : return blk_trace_bio_get_cgid(rq->q, rq->bio);
801 : }
802 :
803 : /*
804 : * blktrace probes
805 : */
806 :
807 : /**
808 : * blk_add_trace_rq - Add a trace for a request oriented action
809 : * @rq: the source request
810 : * @error: return status to log
811 : * @nr_bytes: number of completed bytes
812 : * @what: the action
813 : * @cgid: the cgroup info
814 : *
815 : * Description:
816 : * Records an action against a request. Will log the bio offset + size.
817 : *
818 : **/
819 : static void blk_add_trace_rq(struct request *rq, int error,
820 : unsigned int nr_bytes, u32 what, u64 cgid)
821 : {
822 : struct blk_trace *bt;
823 :
824 : rcu_read_lock();
825 : bt = rcu_dereference(rq->q->blk_trace);
826 : if (likely(!bt)) {
827 : rcu_read_unlock();
828 : return;
829 : }
830 :
831 : if (blk_rq_is_passthrough(rq))
832 : what |= BLK_TC_ACT(BLK_TC_PC);
833 : else
834 : what |= BLK_TC_ACT(BLK_TC_FS);
835 :
836 : __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
837 : rq->cmd_flags, what, error, 0, NULL, cgid);
838 : rcu_read_unlock();
839 : }
840 :
841 : static void blk_add_trace_rq_insert(void *ignore, struct request *rq)
842 : {
843 : blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
844 : blk_trace_request_get_cgid(rq));
845 : }
846 :
847 : static void blk_add_trace_rq_issue(void *ignore, struct request *rq)
848 : {
849 : blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
850 : blk_trace_request_get_cgid(rq));
851 : }
852 :
853 : static void blk_add_trace_rq_merge(void *ignore, struct request *rq)
854 : {
855 : blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
856 : blk_trace_request_get_cgid(rq));
857 : }
858 :
859 : static void blk_add_trace_rq_requeue(void *ignore, struct request *rq)
860 : {
861 : blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
862 : blk_trace_request_get_cgid(rq));
863 : }
864 :
865 : static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
866 : int error, unsigned int nr_bytes)
867 : {
868 : blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
869 : blk_trace_request_get_cgid(rq));
870 : }
871 :
872 : /**
873 : * blk_add_trace_bio - Add a trace for a bio oriented action
874 : * @q: queue the io is for
875 : * @bio: the source bio
876 : * @what: the action
877 : * @error: error, if any
878 : *
879 : * Description:
880 : * Records an action against a bio. Will log the bio offset + size.
881 : *
882 : **/
883 : static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
884 : u32 what, int error)
885 : {
886 : struct blk_trace *bt;
887 :
888 : rcu_read_lock();
889 : bt = rcu_dereference(q->blk_trace);
890 : if (likely(!bt)) {
891 : rcu_read_unlock();
892 : return;
893 : }
894 :
895 : __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
896 : bio_op(bio), bio->bi_opf, what, error, 0, NULL,
897 : blk_trace_bio_get_cgid(q, bio));
898 : rcu_read_unlock();
899 : }
900 :
901 : static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio)
902 : {
903 : blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0);
904 : }
905 :
906 : static void blk_add_trace_bio_complete(void *ignore,
907 : struct request_queue *q, struct bio *bio)
908 : {
909 : blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
910 : blk_status_to_errno(bio->bi_status));
911 : }
912 :
913 : static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio)
914 : {
915 : blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE,
916 : 0);
917 : }
918 :
919 : static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio)
920 : {
921 : blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE,
922 : 0);
923 : }
924 :
925 : static void blk_add_trace_bio_queue(void *ignore, struct bio *bio)
926 : {
927 : blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0);
928 : }
929 :
930 : static void blk_add_trace_getrq(void *ignore, struct bio *bio)
931 : {
932 : blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0);
933 : }
934 :
935 : static void blk_add_trace_plug(void *ignore, struct request_queue *q)
936 : {
937 : struct blk_trace *bt;
938 :
939 : rcu_read_lock();
940 : bt = rcu_dereference(q->blk_trace);
941 : if (bt)
942 : __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
943 : rcu_read_unlock();
944 : }
945 :
946 : static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
947 : unsigned int depth, bool explicit)
948 : {
949 : struct blk_trace *bt;
950 :
951 : rcu_read_lock();
952 : bt = rcu_dereference(q->blk_trace);
953 : if (bt) {
954 : __be64 rpdu = cpu_to_be64(depth);
955 : u32 what;
956 :
957 : if (explicit)
958 : what = BLK_TA_UNPLUG_IO;
959 : else
960 : what = BLK_TA_UNPLUG_TIMER;
961 :
962 : __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
963 : }
964 : rcu_read_unlock();
965 : }
966 :
967 : static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
968 : {
969 : struct request_queue *q = bio->bi_bdev->bd_disk->queue;
970 : struct blk_trace *bt;
971 :
972 : rcu_read_lock();
973 : bt = rcu_dereference(q->blk_trace);
974 : if (bt) {
975 : __be64 rpdu = cpu_to_be64(pdu);
976 :
977 : __blk_add_trace(bt, bio->bi_iter.bi_sector,
978 : bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
979 : BLK_TA_SPLIT,
980 : blk_status_to_errno(bio->bi_status),
981 : sizeof(rpdu), &rpdu,
982 : blk_trace_bio_get_cgid(q, bio));
983 : }
984 : rcu_read_unlock();
985 : }
986 :
987 : /**
988 : * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
989 : * @ignore: trace callback data parameter (not used)
990 : * @bio: the source bio
991 : * @dev: source device
992 : * @from: source sector
993 : *
994 : * Called after a bio is remapped to a different device and/or sector.
995 : **/
996 : static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev,
997 : sector_t from)
998 : {
999 : struct request_queue *q = bio->bi_bdev->bd_disk->queue;
1000 : struct blk_trace *bt;
1001 : struct blk_io_trace_remap r;
1002 :
1003 : rcu_read_lock();
1004 : bt = rcu_dereference(q->blk_trace);
1005 : if (likely(!bt)) {
1006 : rcu_read_unlock();
1007 : return;
1008 : }
1009 :
1010 : r.device_from = cpu_to_be32(dev);
1011 : r.device_to = cpu_to_be32(bio_dev(bio));
1012 : r.sector_from = cpu_to_be64(from);
1013 :
1014 : __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1015 : bio_op(bio), bio->bi_opf, BLK_TA_REMAP,
1016 : blk_status_to_errno(bio->bi_status),
1017 : sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1018 : rcu_read_unlock();
1019 : }
1020 :
1021 : /**
1022 : * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1023 : * @ignore: trace callback data parameter (not used)
1024 : * @rq: the source request
1025 : * @dev: target device
1026 : * @from: source sector
1027 : *
1028 : * Description:
1029 : * Device mapper remaps request to other devices.
1030 : * Add a trace for that action.
1031 : *
1032 : **/
1033 : static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev,
1034 : sector_t from)
1035 : {
1036 : struct blk_trace *bt;
1037 : struct blk_io_trace_remap r;
1038 :
1039 : rcu_read_lock();
1040 : bt = rcu_dereference(rq->q->blk_trace);
1041 : if (likely(!bt)) {
1042 : rcu_read_unlock();
1043 : return;
1044 : }
1045 :
1046 : r.device_from = cpu_to_be32(dev);
1047 : r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
1048 : r.sector_from = cpu_to_be64(from);
1049 :
1050 : __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1051 : rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1052 : sizeof(r), &r, blk_trace_request_get_cgid(rq));
1053 : rcu_read_unlock();
1054 : }
1055 :
1056 : /**
1057 : * blk_add_driver_data - Add binary message with driver-specific data
1058 : * @rq: io request
1059 : * @data: driver-specific data
1060 : * @len: length of driver-specific data
1061 : *
1062 : * Description:
1063 : * Some drivers might want to write driver-specific data per request.
1064 : *
1065 : **/
1066 : void blk_add_driver_data(struct request *rq, void *data, size_t len)
1067 : {
1068 : struct blk_trace *bt;
1069 :
1070 : rcu_read_lock();
1071 : bt = rcu_dereference(rq->q->blk_trace);
1072 : if (likely(!bt)) {
1073 : rcu_read_unlock();
1074 : return;
1075 : }
1076 :
1077 : __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1078 : BLK_TA_DRV_DATA, 0, len, data,
1079 : blk_trace_request_get_cgid(rq));
1080 : rcu_read_unlock();
1081 : }
1082 : EXPORT_SYMBOL_GPL(blk_add_driver_data);
1083 :
1084 : static void blk_register_tracepoints(void)
1085 : {
1086 : int ret;
1087 :
1088 : ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1089 : WARN_ON(ret);
1090 : ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1091 : WARN_ON(ret);
1092 : ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, 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_plug(blk_add_trace_plug, NULL);
1111 : WARN_ON(ret);
1112 : ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1113 : WARN_ON(ret);
1114 : ret = register_trace_block_split(blk_add_trace_split, NULL);
1115 : WARN_ON(ret);
1116 : ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1117 : WARN_ON(ret);
1118 : ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1119 : WARN_ON(ret);
1120 : }
1121 :
1122 : static void blk_unregister_tracepoints(void)
1123 : {
1124 : unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1125 : unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1126 : unregister_trace_block_split(blk_add_trace_split, NULL);
1127 : unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1128 : unregister_trace_block_plug(blk_add_trace_plug, NULL);
1129 : unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1130 : unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1131 : unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1132 : unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1133 : unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1134 : unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1135 : unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1136 : unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1137 : unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1138 : unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1139 : unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1140 :
1141 : tracepoint_synchronize_unregister();
1142 : }
1143 :
1144 : /*
1145 : * struct blk_io_tracer formatting routines
1146 : */
1147 :
1148 : static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1149 : {
1150 : int i = 0;
1151 : int tc = t->action >> BLK_TC_SHIFT;
1152 :
1153 : if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1154 : rwbs[i++] = 'N';
1155 : goto out;
1156 : }
1157 :
1158 : if (tc & BLK_TC_FLUSH)
1159 : rwbs[i++] = 'F';
1160 :
1161 : if (tc & BLK_TC_DISCARD)
1162 : rwbs[i++] = 'D';
1163 : else if (tc & BLK_TC_WRITE)
1164 : rwbs[i++] = 'W';
1165 : else if (t->bytes)
1166 : rwbs[i++] = 'R';
1167 : else
1168 : rwbs[i++] = 'N';
1169 :
1170 : if (tc & BLK_TC_FUA)
1171 : rwbs[i++] = 'F';
1172 : if (tc & BLK_TC_AHEAD)
1173 : rwbs[i++] = 'A';
1174 : if (tc & BLK_TC_SYNC)
1175 : rwbs[i++] = 'S';
1176 : if (tc & BLK_TC_META)
1177 : rwbs[i++] = 'M';
1178 : out:
1179 : rwbs[i] = '\0';
1180 : }
1181 :
1182 : static inline
1183 : const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1184 : {
1185 : return (const struct blk_io_trace *)ent;
1186 : }
1187 :
1188 : static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1189 : {
1190 : return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
1191 : }
1192 :
1193 : static inline u64 t_cgid(const struct trace_entry *ent)
1194 : {
1195 : return *(u64 *)(te_blk_io_trace(ent) + 1);
1196 : }
1197 :
1198 : static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1199 : {
1200 : return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
1201 : }
1202 :
1203 : static inline u32 t_action(const struct trace_entry *ent)
1204 : {
1205 : return te_blk_io_trace(ent)->action;
1206 : }
1207 :
1208 : static inline u32 t_bytes(const struct trace_entry *ent)
1209 : {
1210 : return te_blk_io_trace(ent)->bytes;
1211 : }
1212 :
1213 : static inline u32 t_sec(const struct trace_entry *ent)
1214 : {
1215 : return te_blk_io_trace(ent)->bytes >> 9;
1216 : }
1217 :
1218 : static inline unsigned long long t_sector(const struct trace_entry *ent)
1219 : {
1220 : return te_blk_io_trace(ent)->sector;
1221 : }
1222 :
1223 : static inline __u16 t_error(const struct trace_entry *ent)
1224 : {
1225 : return te_blk_io_trace(ent)->error;
1226 : }
1227 :
1228 : static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1229 : {
1230 : const __be64 *val = pdu_start(ent, has_cg);
1231 : return be64_to_cpu(*val);
1232 : }
1233 :
1234 : typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1235 : bool has_cg);
1236 :
1237 : static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1238 : bool has_cg)
1239 : {
1240 : char rwbs[RWBS_LEN];
1241 : unsigned long long ts = iter->ts;
1242 : unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1243 : unsigned secs = (unsigned long)ts;
1244 : const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1245 :
1246 : fill_rwbs(rwbs, t);
1247 :
1248 : trace_seq_printf(&iter->seq,
1249 : "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1250 : MAJOR(t->device), MINOR(t->device), iter->cpu,
1251 : secs, nsec_rem, iter->ent->pid, act, rwbs);
1252 : }
1253 :
1254 : static void blk_log_action(struct trace_iterator *iter, const char *act,
1255 : bool has_cg)
1256 : {
1257 : char rwbs[RWBS_LEN];
1258 : const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1259 :
1260 : fill_rwbs(rwbs, t);
1261 : if (has_cg) {
1262 : u64 id = t_cgid(iter->ent);
1263 :
1264 : if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1265 : char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1266 :
1267 : cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1268 : sizeof(blkcg_name_buf));
1269 : trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1270 : MAJOR(t->device), MINOR(t->device),
1271 : blkcg_name_buf, act, rwbs);
1272 : } else {
1273 : /*
1274 : * The cgid portion used to be "INO,GEN". Userland
1275 : * builds a FILEID_INO32_GEN fid out of them and
1276 : * opens the cgroup using open_by_handle_at(2).
1277 : * While 32bit ino setups are still the same, 64bit
1278 : * ones now use the 64bit ino as the whole ID and
1279 : * no longer use generation.
1280 : *
1281 : * Regardless of the content, always output
1282 : * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
1283 : * be mapped back to @id on both 64 and 32bit ino
1284 : * setups. See __kernfs_fh_to_dentry().
1285 : */
1286 : trace_seq_printf(&iter->seq,
1287 : "%3d,%-3d %llx,%-llx %2s %3s ",
1288 : MAJOR(t->device), MINOR(t->device),
1289 : id & U32_MAX, id >> 32, act, rwbs);
1290 : }
1291 : } else
1292 : trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1293 : MAJOR(t->device), MINOR(t->device), act, rwbs);
1294 : }
1295 :
1296 : static void blk_log_dump_pdu(struct trace_seq *s,
1297 : const struct trace_entry *ent, bool has_cg)
1298 : {
1299 : const unsigned char *pdu_buf;
1300 : int pdu_len;
1301 : int i, end;
1302 :
1303 : pdu_buf = pdu_start(ent, has_cg);
1304 : pdu_len = pdu_real_len(ent, has_cg);
1305 :
1306 : if (!pdu_len)
1307 : return;
1308 :
1309 : /* find the last zero that needs to be printed */
1310 : for (end = pdu_len - 1; end >= 0; end--)
1311 : if (pdu_buf[end])
1312 : break;
1313 : end++;
1314 :
1315 : trace_seq_putc(s, '(');
1316 :
1317 : for (i = 0; i < pdu_len; i++) {
1318 :
1319 : trace_seq_printf(s, "%s%02x",
1320 : i == 0 ? "" : " ", pdu_buf[i]);
1321 :
1322 : /*
1323 : * stop when the rest is just zeros and indicate so
1324 : * with a ".." appended
1325 : */
1326 : if (i == end && end != pdu_len - 1) {
1327 : trace_seq_puts(s, " ..) ");
1328 : return;
1329 : }
1330 : }
1331 :
1332 : trace_seq_puts(s, ") ");
1333 : }
1334 :
1335 : static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1336 : {
1337 : char cmd[TASK_COMM_LEN];
1338 :
1339 : trace_find_cmdline(ent->pid, cmd);
1340 :
1341 : if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1342 : trace_seq_printf(s, "%u ", t_bytes(ent));
1343 : blk_log_dump_pdu(s, ent, has_cg);
1344 : trace_seq_printf(s, "[%s]\n", cmd);
1345 : } else {
1346 : if (t_sec(ent))
1347 : trace_seq_printf(s, "%llu + %u [%s]\n",
1348 : t_sector(ent), t_sec(ent), cmd);
1349 : else
1350 : trace_seq_printf(s, "[%s]\n", cmd);
1351 : }
1352 : }
1353 :
1354 : static void blk_log_with_error(struct trace_seq *s,
1355 : const struct trace_entry *ent, bool has_cg)
1356 : {
1357 : if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1358 : blk_log_dump_pdu(s, ent, has_cg);
1359 : trace_seq_printf(s, "[%d]\n", t_error(ent));
1360 : } else {
1361 : if (t_sec(ent))
1362 : trace_seq_printf(s, "%llu + %u [%d]\n",
1363 : t_sector(ent),
1364 : t_sec(ent), t_error(ent));
1365 : else
1366 : trace_seq_printf(s, "%llu [%d]\n",
1367 : t_sector(ent), t_error(ent));
1368 : }
1369 : }
1370 :
1371 : static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1372 : {
1373 : const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1374 :
1375 : trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1376 : t_sector(ent), t_sec(ent),
1377 : MAJOR(be32_to_cpu(__r->device_from)),
1378 : MINOR(be32_to_cpu(__r->device_from)),
1379 : be64_to_cpu(__r->sector_from));
1380 : }
1381 :
1382 : static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1383 : {
1384 : char cmd[TASK_COMM_LEN];
1385 :
1386 : trace_find_cmdline(ent->pid, cmd);
1387 :
1388 : trace_seq_printf(s, "[%s]\n", cmd);
1389 : }
1390 :
1391 : static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1392 : {
1393 : char cmd[TASK_COMM_LEN];
1394 :
1395 : trace_find_cmdline(ent->pid, cmd);
1396 :
1397 : trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1398 : }
1399 :
1400 : static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1401 : {
1402 : char cmd[TASK_COMM_LEN];
1403 :
1404 : trace_find_cmdline(ent->pid, cmd);
1405 :
1406 : trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1407 : get_pdu_int(ent, has_cg), cmd);
1408 : }
1409 :
1410 : static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1411 : bool has_cg)
1412 : {
1413 :
1414 : trace_seq_putmem(s, pdu_start(ent, has_cg),
1415 : pdu_real_len(ent, has_cg));
1416 : trace_seq_putc(s, '\n');
1417 : }
1418 :
1419 : /*
1420 : * struct tracer operations
1421 : */
1422 :
1423 : static void blk_tracer_print_header(struct seq_file *m)
1424 : {
1425 : if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1426 : return;
1427 : seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1428 : "# | | | | | |\n");
1429 : }
1430 :
1431 : static void blk_tracer_start(struct trace_array *tr)
1432 : {
1433 : blk_tracer_enabled = true;
1434 : }
1435 :
1436 : static int blk_tracer_init(struct trace_array *tr)
1437 : {
1438 : blk_tr = tr;
1439 : blk_tracer_start(tr);
1440 : return 0;
1441 : }
1442 :
1443 : static void blk_tracer_stop(struct trace_array *tr)
1444 : {
1445 : blk_tracer_enabled = false;
1446 : }
1447 :
1448 : static void blk_tracer_reset(struct trace_array *tr)
1449 : {
1450 : blk_tracer_stop(tr);
1451 : }
1452 :
1453 : static const struct {
1454 : const char *act[2];
1455 : void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1456 : bool has_cg);
1457 : } what2act[] = {
1458 : [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1459 : [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1460 : [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1461 : [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1462 : [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1463 : [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1464 : [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1465 : [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1466 : [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1467 : [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1468 : [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1469 : [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1470 : [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1471 : [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1472 : [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1473 : };
1474 :
1475 : static enum print_line_t print_one_line(struct trace_iterator *iter,
1476 : bool classic)
1477 : {
1478 : struct trace_array *tr = iter->tr;
1479 : struct trace_seq *s = &iter->seq;
1480 : const struct blk_io_trace *t;
1481 : u16 what;
1482 : bool long_act;
1483 : blk_log_action_t *log_action;
1484 : bool has_cg;
1485 :
1486 : t = te_blk_io_trace(iter->ent);
1487 : what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1488 : long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1489 : log_action = classic ? &blk_log_action_classic : &blk_log_action;
1490 : has_cg = t->action & __BLK_TA_CGROUP;
1491 :
1492 : if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1493 : log_action(iter, long_act ? "message" : "m", has_cg);
1494 : blk_log_msg(s, iter->ent, has_cg);
1495 : return trace_handle_return(s);
1496 : }
1497 :
1498 : if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1499 : trace_seq_printf(s, "Unknown action %x\n", what);
1500 : else {
1501 : log_action(iter, what2act[what].act[long_act], has_cg);
1502 : what2act[what].print(s, iter->ent, has_cg);
1503 : }
1504 :
1505 : return trace_handle_return(s);
1506 : }
1507 :
1508 : static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1509 : int flags, struct trace_event *event)
1510 : {
1511 : return print_one_line(iter, false);
1512 : }
1513 :
1514 : static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1515 : {
1516 : struct trace_seq *s = &iter->seq;
1517 : struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1518 : const int offset = offsetof(struct blk_io_trace, sector);
1519 : struct blk_io_trace old = {
1520 : .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1521 : .time = iter->ts,
1522 : };
1523 :
1524 : trace_seq_putmem(s, &old, offset);
1525 : trace_seq_putmem(s, &t->sector,
1526 : sizeof(old) - offset + t->pdu_len);
1527 : }
1528 :
1529 : static enum print_line_t
1530 : blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1531 : struct trace_event *event)
1532 : {
1533 : blk_trace_synthesize_old_trace(iter);
1534 :
1535 : return trace_handle_return(&iter->seq);
1536 : }
1537 :
1538 : static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1539 : {
1540 : if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1541 : return TRACE_TYPE_UNHANDLED;
1542 :
1543 : return print_one_line(iter, true);
1544 : }
1545 :
1546 : static int
1547 : blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1548 : {
1549 : /* don't output context-info for blk_classic output */
1550 : if (bit == TRACE_BLK_OPT_CLASSIC) {
1551 : if (set)
1552 : tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1553 : else
1554 : tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1555 : }
1556 : return 0;
1557 : }
1558 :
1559 : static struct tracer blk_tracer __read_mostly = {
1560 : .name = "blk",
1561 : .init = blk_tracer_init,
1562 : .reset = blk_tracer_reset,
1563 : .start = blk_tracer_start,
1564 : .stop = blk_tracer_stop,
1565 : .print_header = blk_tracer_print_header,
1566 : .print_line = blk_tracer_print_line,
1567 : .flags = &blk_tracer_flags,
1568 : .set_flag = blk_tracer_set_flag,
1569 : };
1570 :
1571 : static struct trace_event_functions trace_blk_event_funcs = {
1572 : .trace = blk_trace_event_print,
1573 : .binary = blk_trace_event_print_binary,
1574 : };
1575 :
1576 : static struct trace_event trace_blk_event = {
1577 : .type = TRACE_BLK,
1578 : .funcs = &trace_blk_event_funcs,
1579 : };
1580 :
1581 : static int __init init_blk_tracer(void)
1582 : {
1583 : if (!register_trace_event(&trace_blk_event)) {
1584 : pr_warn("Warning: could not register block events\n");
1585 : return 1;
1586 : }
1587 :
1588 : if (register_tracer(&blk_tracer) != 0) {
1589 : pr_warn("Warning: could not register the block tracer\n");
1590 : unregister_trace_event(&trace_blk_event);
1591 : return 1;
1592 : }
1593 :
1594 : return 0;
1595 : }
1596 :
1597 : device_initcall(init_blk_tracer);
1598 :
1599 : static int blk_trace_remove_queue(struct request_queue *q)
1600 : {
1601 : struct blk_trace *bt;
1602 :
1603 : bt = rcu_replace_pointer(q->blk_trace, NULL,
1604 : lockdep_is_held(&q->debugfs_mutex));
1605 : if (bt == NULL)
1606 : return -EINVAL;
1607 :
1608 : put_probe_ref();
1609 : synchronize_rcu();
1610 : blk_trace_free(bt);
1611 : return 0;
1612 : }
1613 :
1614 : /*
1615 : * Setup everything required to start tracing
1616 : */
1617 : static int blk_trace_setup_queue(struct request_queue *q,
1618 : struct block_device *bdev)
1619 : {
1620 : struct blk_trace *bt = NULL;
1621 : int ret = -ENOMEM;
1622 :
1623 : bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1624 : if (!bt)
1625 : return -ENOMEM;
1626 :
1627 : bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1628 : if (!bt->msg_data)
1629 : goto free_bt;
1630 :
1631 : bt->dev = bdev->bd_dev;
1632 : bt->act_mask = (u16)-1;
1633 :
1634 : blk_trace_setup_lba(bt, bdev);
1635 :
1636 : rcu_assign_pointer(q->blk_trace, bt);
1637 : get_probe_ref();
1638 : return 0;
1639 :
1640 : free_bt:
1641 : blk_trace_free(bt);
1642 : return ret;
1643 : }
1644 :
1645 : /*
1646 : * sysfs interface to enable and configure tracing
1647 : */
1648 :
1649 : static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1650 : struct device_attribute *attr,
1651 : char *buf);
1652 : static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1653 : struct device_attribute *attr,
1654 : const char *buf, size_t count);
1655 : #define BLK_TRACE_DEVICE_ATTR(_name) \
1656 : DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1657 : sysfs_blk_trace_attr_show, \
1658 : sysfs_blk_trace_attr_store)
1659 :
1660 : static BLK_TRACE_DEVICE_ATTR(enable);
1661 : static BLK_TRACE_DEVICE_ATTR(act_mask);
1662 : static BLK_TRACE_DEVICE_ATTR(pid);
1663 : static BLK_TRACE_DEVICE_ATTR(start_lba);
1664 : static BLK_TRACE_DEVICE_ATTR(end_lba);
1665 :
1666 : static struct attribute *blk_trace_attrs[] = {
1667 : &dev_attr_enable.attr,
1668 : &dev_attr_act_mask.attr,
1669 : &dev_attr_pid.attr,
1670 : &dev_attr_start_lba.attr,
1671 : &dev_attr_end_lba.attr,
1672 : NULL
1673 : };
1674 :
1675 : struct attribute_group blk_trace_attr_group = {
1676 : .name = "trace",
1677 : .attrs = blk_trace_attrs,
1678 : };
1679 :
1680 : static const struct {
1681 : int mask;
1682 : const char *str;
1683 : } mask_maps[] = {
1684 : { BLK_TC_READ, "read" },
1685 : { BLK_TC_WRITE, "write" },
1686 : { BLK_TC_FLUSH, "flush" },
1687 : { BLK_TC_SYNC, "sync" },
1688 : { BLK_TC_QUEUE, "queue" },
1689 : { BLK_TC_REQUEUE, "requeue" },
1690 : { BLK_TC_ISSUE, "issue" },
1691 : { BLK_TC_COMPLETE, "complete" },
1692 : { BLK_TC_FS, "fs" },
1693 : { BLK_TC_PC, "pc" },
1694 : { BLK_TC_NOTIFY, "notify" },
1695 : { BLK_TC_AHEAD, "ahead" },
1696 : { BLK_TC_META, "meta" },
1697 : { BLK_TC_DISCARD, "discard" },
1698 : { BLK_TC_DRV_DATA, "drv_data" },
1699 : { BLK_TC_FUA, "fua" },
1700 : };
1701 :
1702 : static int blk_trace_str2mask(const char *str)
1703 : {
1704 : int i;
1705 : int mask = 0;
1706 : char *buf, *s, *token;
1707 :
1708 : buf = kstrdup(str, GFP_KERNEL);
1709 : if (buf == NULL)
1710 : return -ENOMEM;
1711 : s = strstrip(buf);
1712 :
1713 : while (1) {
1714 : token = strsep(&s, ",");
1715 : if (token == NULL)
1716 : break;
1717 :
1718 : if (*token == '\0')
1719 : continue;
1720 :
1721 : for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1722 : if (strcasecmp(token, mask_maps[i].str) == 0) {
1723 : mask |= mask_maps[i].mask;
1724 : break;
1725 : }
1726 : }
1727 : if (i == ARRAY_SIZE(mask_maps)) {
1728 : mask = -EINVAL;
1729 : break;
1730 : }
1731 : }
1732 : kfree(buf);
1733 :
1734 : return mask;
1735 : }
1736 :
1737 : static ssize_t blk_trace_mask2str(char *buf, int mask)
1738 : {
1739 : int i;
1740 : char *p = buf;
1741 :
1742 : for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1743 : if (mask & mask_maps[i].mask) {
1744 : p += sprintf(p, "%s%s",
1745 : (p == buf) ? "" : ",", mask_maps[i].str);
1746 : }
1747 : }
1748 : *p++ = '\n';
1749 :
1750 : return p - buf;
1751 : }
1752 :
1753 : static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1754 : struct device_attribute *attr,
1755 : char *buf)
1756 : {
1757 : struct block_device *bdev = dev_to_bdev(dev);
1758 : struct request_queue *q = bdev_get_queue(bdev);
1759 : struct blk_trace *bt;
1760 : ssize_t ret = -ENXIO;
1761 :
1762 : mutex_lock(&q->debugfs_mutex);
1763 :
1764 : bt = rcu_dereference_protected(q->blk_trace,
1765 : lockdep_is_held(&q->debugfs_mutex));
1766 : if (attr == &dev_attr_enable) {
1767 : ret = sprintf(buf, "%u\n", !!bt);
1768 : goto out_unlock_bdev;
1769 : }
1770 :
1771 : if (bt == NULL)
1772 : ret = sprintf(buf, "disabled\n");
1773 : else if (attr == &dev_attr_act_mask)
1774 : ret = blk_trace_mask2str(buf, bt->act_mask);
1775 : else if (attr == &dev_attr_pid)
1776 : ret = sprintf(buf, "%u\n", bt->pid);
1777 : else if (attr == &dev_attr_start_lba)
1778 : ret = sprintf(buf, "%llu\n", bt->start_lba);
1779 : else if (attr == &dev_attr_end_lba)
1780 : ret = sprintf(buf, "%llu\n", bt->end_lba);
1781 :
1782 : out_unlock_bdev:
1783 : mutex_unlock(&q->debugfs_mutex);
1784 : return ret;
1785 : }
1786 :
1787 : static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1788 : struct device_attribute *attr,
1789 : const char *buf, size_t count)
1790 : {
1791 : struct block_device *bdev = dev_to_bdev(dev);
1792 : struct request_queue *q = bdev_get_queue(bdev);
1793 : struct blk_trace *bt;
1794 : u64 value;
1795 : ssize_t ret = -EINVAL;
1796 :
1797 : if (count == 0)
1798 : goto out;
1799 :
1800 : if (attr == &dev_attr_act_mask) {
1801 : if (kstrtoull(buf, 0, &value)) {
1802 : /* Assume it is a list of trace category names */
1803 : ret = blk_trace_str2mask(buf);
1804 : if (ret < 0)
1805 : goto out;
1806 : value = ret;
1807 : }
1808 : } else {
1809 : if (kstrtoull(buf, 0, &value))
1810 : goto out;
1811 : }
1812 :
1813 : mutex_lock(&q->debugfs_mutex);
1814 :
1815 : bt = rcu_dereference_protected(q->blk_trace,
1816 : lockdep_is_held(&q->debugfs_mutex));
1817 : if (attr == &dev_attr_enable) {
1818 : if (!!value == !!bt) {
1819 : ret = 0;
1820 : goto out_unlock_bdev;
1821 : }
1822 : if (value)
1823 : ret = blk_trace_setup_queue(q, bdev);
1824 : else
1825 : ret = blk_trace_remove_queue(q);
1826 : goto out_unlock_bdev;
1827 : }
1828 :
1829 : ret = 0;
1830 : if (bt == NULL) {
1831 : ret = blk_trace_setup_queue(q, bdev);
1832 : bt = rcu_dereference_protected(q->blk_trace,
1833 : lockdep_is_held(&q->debugfs_mutex));
1834 : }
1835 :
1836 : if (ret == 0) {
1837 : if (attr == &dev_attr_act_mask)
1838 : bt->act_mask = value;
1839 : else if (attr == &dev_attr_pid)
1840 : bt->pid = value;
1841 : else if (attr == &dev_attr_start_lba)
1842 : bt->start_lba = value;
1843 : else if (attr == &dev_attr_end_lba)
1844 : bt->end_lba = value;
1845 : }
1846 :
1847 : out_unlock_bdev:
1848 : mutex_unlock(&q->debugfs_mutex);
1849 : out:
1850 : return ret ? ret : count;
1851 : }
1852 :
1853 : int blk_trace_init_sysfs(struct device *dev)
1854 : {
1855 : return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1856 : }
1857 :
1858 : void blk_trace_remove_sysfs(struct device *dev)
1859 : {
1860 : sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1861 : }
1862 :
1863 : #endif /* CONFIG_BLK_DEV_IO_TRACE */
1864 :
1865 : #ifdef CONFIG_EVENT_TRACING
1866 :
1867 : /**
1868 : * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string.
1869 : * @rwbs: buffer to be filled
1870 : * @op: REQ_OP_XXX for the tracepoint
1871 : *
1872 : * Description:
1873 : * Maps the REQ_OP_XXX to character and fills the buffer provided by the
1874 : * caller with resulting string.
1875 : *
1876 : **/
1877 0 : void blk_fill_rwbs(char *rwbs, unsigned int op)
1878 : {
1879 0 : int i = 0;
1880 :
1881 0 : if (op & REQ_PREFLUSH)
1882 0 : rwbs[i++] = 'F';
1883 :
1884 0 : switch (op & REQ_OP_MASK) {
1885 0 : case REQ_OP_WRITE:
1886 : case REQ_OP_WRITE_SAME:
1887 0 : rwbs[i++] = 'W';
1888 0 : break;
1889 0 : case REQ_OP_DISCARD:
1890 0 : rwbs[i++] = 'D';
1891 0 : break;
1892 0 : case REQ_OP_SECURE_ERASE:
1893 0 : rwbs[i++] = 'D';
1894 0 : rwbs[i++] = 'E';
1895 0 : break;
1896 0 : case REQ_OP_FLUSH:
1897 0 : rwbs[i++] = 'F';
1898 0 : break;
1899 0 : case REQ_OP_READ:
1900 0 : rwbs[i++] = 'R';
1901 0 : break;
1902 0 : default:
1903 0 : rwbs[i++] = 'N';
1904 : }
1905 :
1906 0 : if (op & REQ_FUA)
1907 0 : rwbs[i++] = 'F';
1908 0 : if (op & REQ_RAHEAD)
1909 0 : rwbs[i++] = 'A';
1910 0 : if (op & REQ_SYNC)
1911 0 : rwbs[i++] = 'S';
1912 0 : if (op & REQ_META)
1913 0 : rwbs[i++] = 'M';
1914 :
1915 0 : rwbs[i] = '\0';
1916 0 : }
1917 : EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1918 :
1919 : #endif /* CONFIG_EVENT_TRACING */
1920 :
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