Merge tag 'for-4.19/post-20180822' of git://git.kernel.dk/linux-block
[sfrench/cifs-2.6.git] / kernel / trace / blktrace.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
4  *
5  */
6 #include <linux/kernel.h>
7 #include <linux/blkdev.h>
8 #include <linux/blktrace_api.h>
9 #include <linux/percpu.h>
10 #include <linux/init.h>
11 #include <linux/mutex.h>
12 #include <linux/slab.h>
13 #include <linux/debugfs.h>
14 #include <linux/export.h>
15 #include <linux/time.h>
16 #include <linux/uaccess.h>
17 #include <linux/list.h>
18 #include <linux/blk-cgroup.h>
19
20 #include "../../block/blk.h"
21
22 #include <trace/events/block.h>
23
24 #include "trace_output.h"
25
26 #ifdef CONFIG_BLK_DEV_IO_TRACE
27
28 static unsigned int blktrace_seq __read_mostly = 1;
29
30 static struct trace_array *blk_tr;
31 static bool blk_tracer_enabled __read_mostly;
32
33 static LIST_HEAD(running_trace_list);
34 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
35
36 /* Select an alternative, minimalistic output than the original one */
37 #define TRACE_BLK_OPT_CLASSIC   0x1
38 #define TRACE_BLK_OPT_CGROUP    0x2
39 #define TRACE_BLK_OPT_CGNAME    0x4
40
41 static struct tracer_opt blk_tracer_opts[] = {
42         /* Default disable the minimalistic output */
43         { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
44 #ifdef CONFIG_BLK_CGROUP
45         { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
46         { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
47 #endif
48         { }
49 };
50
51 static struct tracer_flags blk_tracer_flags = {
52         .val  = 0,
53         .opts = blk_tracer_opts,
54 };
55
56 /* Global reference count of probes */
57 static DEFINE_MUTEX(blk_probe_mutex);
58 static int blk_probes_ref;
59
60 static void blk_register_tracepoints(void);
61 static void blk_unregister_tracepoints(void);
62
63 /*
64  * Send out a notify message.
65  */
66 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
67                        const void *data, size_t len,
68                        union kernfs_node_id *cgid)
69 {
70         struct blk_io_trace *t;
71         struct ring_buffer_event *event = NULL;
72         struct ring_buffer *buffer = NULL;
73         int pc = 0;
74         int cpu = smp_processor_id();
75         bool blk_tracer = blk_tracer_enabled;
76         ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
77
78         if (blk_tracer) {
79                 buffer = blk_tr->trace_buffer.buffer;
80                 pc = preempt_count();
81                 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
82                                                   sizeof(*t) + len + cgid_len,
83                                                   0, pc);
84                 if (!event)
85                         return;
86                 t = ring_buffer_event_data(event);
87                 goto record_it;
88         }
89
90         if (!bt->rchan)
91                 return;
92
93         t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len);
94         if (t) {
95                 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
96                 t->time = ktime_to_ns(ktime_get());
97 record_it:
98                 t->device = bt->dev;
99                 t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
100                 t->pid = pid;
101                 t->cpu = cpu;
102                 t->pdu_len = len + cgid_len;
103                 if (cgid)
104                         memcpy((void *)t + sizeof(*t), cgid, cgid_len);
105                 memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
106
107                 if (blk_tracer)
108                         trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
109         }
110 }
111
112 /*
113  * Send out a notify for this process, if we haven't done so since a trace
114  * started
115  */
116 static void trace_note_tsk(struct task_struct *tsk)
117 {
118         unsigned long flags;
119         struct blk_trace *bt;
120
121         tsk->btrace_seq = blktrace_seq;
122         spin_lock_irqsave(&running_trace_lock, flags);
123         list_for_each_entry(bt, &running_trace_list, running_list) {
124                 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
125                            sizeof(tsk->comm), NULL);
126         }
127         spin_unlock_irqrestore(&running_trace_lock, flags);
128 }
129
130 static void trace_note_time(struct blk_trace *bt)
131 {
132         struct timespec64 now;
133         unsigned long flags;
134         u32 words[2];
135
136         /* need to check user space to see if this breaks in y2038 or y2106 */
137         ktime_get_real_ts64(&now);
138         words[0] = (u32)now.tv_sec;
139         words[1] = now.tv_nsec;
140
141         local_irq_save(flags);
142         trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), NULL);
143         local_irq_restore(flags);
144 }
145
146 void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
147         const char *fmt, ...)
148 {
149         int n;
150         va_list args;
151         unsigned long flags;
152         char *buf;
153
154         if (unlikely(bt->trace_state != Blktrace_running &&
155                      !blk_tracer_enabled))
156                 return;
157
158         /*
159          * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
160          * message to the trace.
161          */
162         if (!(bt->act_mask & BLK_TC_NOTIFY))
163                 return;
164
165         local_irq_save(flags);
166         buf = this_cpu_ptr(bt->msg_data);
167         va_start(args, fmt);
168         n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
169         va_end(args);
170
171         if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
172                 blkcg = NULL;
173 #ifdef CONFIG_BLK_CGROUP
174         trace_note(bt, 0, BLK_TN_MESSAGE, buf, n,
175                 blkcg ? cgroup_get_kernfs_id(blkcg->css.cgroup) : NULL);
176 #else
177         trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL);
178 #endif
179         local_irq_restore(flags);
180 }
181 EXPORT_SYMBOL_GPL(__trace_note_message);
182
183 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
184                          pid_t pid)
185 {
186         if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
187                 return 1;
188         if (sector && (sector < bt->start_lba || sector > bt->end_lba))
189                 return 1;
190         if (bt->pid && pid != bt->pid)
191                 return 1;
192
193         return 0;
194 }
195
196 /*
197  * Data direction bit lookup
198  */
199 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
200                                  BLK_TC_ACT(BLK_TC_WRITE) };
201
202 #define BLK_TC_RAHEAD           BLK_TC_AHEAD
203 #define BLK_TC_PREFLUSH         BLK_TC_FLUSH
204
205 /* The ilog2() calls fall out because they're constant */
206 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
207           (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
208
209 /*
210  * The worker for the various blk_add_trace*() types. Fills out a
211  * blk_io_trace structure and places it in a per-cpu subbuffer.
212  */
213 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
214                      int op, int op_flags, u32 what, int error, int pdu_len,
215                      void *pdu_data, union kernfs_node_id *cgid)
216 {
217         struct task_struct *tsk = current;
218         struct ring_buffer_event *event = NULL;
219         struct ring_buffer *buffer = NULL;
220         struct blk_io_trace *t;
221         unsigned long flags = 0;
222         unsigned long *sequence;
223         pid_t pid;
224         int cpu, pc = 0;
225         bool blk_tracer = blk_tracer_enabled;
226         ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
227
228         if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
229                 return;
230
231         what |= ddir_act[op_is_write(op) ? WRITE : READ];
232         what |= MASK_TC_BIT(op_flags, SYNC);
233         what |= MASK_TC_BIT(op_flags, RAHEAD);
234         what |= MASK_TC_BIT(op_flags, META);
235         what |= MASK_TC_BIT(op_flags, PREFLUSH);
236         what |= MASK_TC_BIT(op_flags, FUA);
237         if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
238                 what |= BLK_TC_ACT(BLK_TC_DISCARD);
239         if (op == REQ_OP_FLUSH)
240                 what |= BLK_TC_ACT(BLK_TC_FLUSH);
241         if (cgid)
242                 what |= __BLK_TA_CGROUP;
243
244         pid = tsk->pid;
245         if (act_log_check(bt, what, sector, pid))
246                 return;
247         cpu = raw_smp_processor_id();
248
249         if (blk_tracer) {
250                 tracing_record_cmdline(current);
251
252                 buffer = blk_tr->trace_buffer.buffer;
253                 pc = preempt_count();
254                 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
255                                                   sizeof(*t) + pdu_len + cgid_len,
256                                                   0, pc);
257                 if (!event)
258                         return;
259                 t = ring_buffer_event_data(event);
260                 goto record_it;
261         }
262
263         if (unlikely(tsk->btrace_seq != blktrace_seq))
264                 trace_note_tsk(tsk);
265
266         /*
267          * A word about the locking here - we disable interrupts to reserve
268          * some space in the relay per-cpu buffer, to prevent an irq
269          * from coming in and stepping on our toes.
270          */
271         local_irq_save(flags);
272         t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
273         if (t) {
274                 sequence = per_cpu_ptr(bt->sequence, cpu);
275
276                 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
277                 t->sequence = ++(*sequence);
278                 t->time = ktime_to_ns(ktime_get());
279 record_it:
280                 /*
281                  * These two are not needed in ftrace as they are in the
282                  * generic trace_entry, filled by tracing_generic_entry_update,
283                  * but for the trace_event->bin() synthesizer benefit we do it
284                  * here too.
285                  */
286                 t->cpu = cpu;
287                 t->pid = pid;
288
289                 t->sector = sector;
290                 t->bytes = bytes;
291                 t->action = what;
292                 t->device = bt->dev;
293                 t->error = error;
294                 t->pdu_len = pdu_len + cgid_len;
295
296                 if (cgid_len)
297                         memcpy((void *)t + sizeof(*t), cgid, cgid_len);
298                 if (pdu_len)
299                         memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
300
301                 if (blk_tracer) {
302                         trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
303                         return;
304                 }
305         }
306
307         local_irq_restore(flags);
308 }
309
310 static void blk_trace_free(struct blk_trace *bt)
311 {
312         debugfs_remove(bt->msg_file);
313         debugfs_remove(bt->dropped_file);
314         relay_close(bt->rchan);
315         debugfs_remove(bt->dir);
316         free_percpu(bt->sequence);
317         free_percpu(bt->msg_data);
318         kfree(bt);
319 }
320
321 static void get_probe_ref(void)
322 {
323         mutex_lock(&blk_probe_mutex);
324         if (++blk_probes_ref == 1)
325                 blk_register_tracepoints();
326         mutex_unlock(&blk_probe_mutex);
327 }
328
329 static void put_probe_ref(void)
330 {
331         mutex_lock(&blk_probe_mutex);
332         if (!--blk_probes_ref)
333                 blk_unregister_tracepoints();
334         mutex_unlock(&blk_probe_mutex);
335 }
336
337 static void blk_trace_cleanup(struct blk_trace *bt)
338 {
339         blk_trace_free(bt);
340         put_probe_ref();
341 }
342
343 static int __blk_trace_remove(struct request_queue *q)
344 {
345         struct blk_trace *bt;
346
347         bt = xchg(&q->blk_trace, NULL);
348         if (!bt)
349                 return -EINVAL;
350
351         if (bt->trace_state != Blktrace_running)
352                 blk_trace_cleanup(bt);
353
354         return 0;
355 }
356
357 int blk_trace_remove(struct request_queue *q)
358 {
359         int ret;
360
361         mutex_lock(&q->blk_trace_mutex);
362         ret = __blk_trace_remove(q);
363         mutex_unlock(&q->blk_trace_mutex);
364
365         return ret;
366 }
367 EXPORT_SYMBOL_GPL(blk_trace_remove);
368
369 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
370                                 size_t count, loff_t *ppos)
371 {
372         struct blk_trace *bt = filp->private_data;
373         char buf[16];
374
375         snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
376
377         return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
378 }
379
380 static const struct file_operations blk_dropped_fops = {
381         .owner =        THIS_MODULE,
382         .open =         simple_open,
383         .read =         blk_dropped_read,
384         .llseek =       default_llseek,
385 };
386
387 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
388                                 size_t count, loff_t *ppos)
389 {
390         char *msg;
391         struct blk_trace *bt;
392
393         if (count >= BLK_TN_MAX_MSG)
394                 return -EINVAL;
395
396         msg = memdup_user_nul(buffer, count);
397         if (IS_ERR(msg))
398                 return PTR_ERR(msg);
399
400         bt = filp->private_data;
401         __trace_note_message(bt, NULL, "%s", msg);
402         kfree(msg);
403
404         return count;
405 }
406
407 static const struct file_operations blk_msg_fops = {
408         .owner =        THIS_MODULE,
409         .open =         simple_open,
410         .write =        blk_msg_write,
411         .llseek =       noop_llseek,
412 };
413
414 /*
415  * Keep track of how many times we encountered a full subbuffer, to aid
416  * the user space app in telling how many lost events there were.
417  */
418 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
419                                      void *prev_subbuf, size_t prev_padding)
420 {
421         struct blk_trace *bt;
422
423         if (!relay_buf_full(buf))
424                 return 1;
425
426         bt = buf->chan->private_data;
427         atomic_inc(&bt->dropped);
428         return 0;
429 }
430
431 static int blk_remove_buf_file_callback(struct dentry *dentry)
432 {
433         debugfs_remove(dentry);
434
435         return 0;
436 }
437
438 static struct dentry *blk_create_buf_file_callback(const char *filename,
439                                                    struct dentry *parent,
440                                                    umode_t mode,
441                                                    struct rchan_buf *buf,
442                                                    int *is_global)
443 {
444         return debugfs_create_file(filename, mode, parent, buf,
445                                         &relay_file_operations);
446 }
447
448 static struct rchan_callbacks blk_relay_callbacks = {
449         .subbuf_start           = blk_subbuf_start_callback,
450         .create_buf_file        = blk_create_buf_file_callback,
451         .remove_buf_file        = blk_remove_buf_file_callback,
452 };
453
454 static void blk_trace_setup_lba(struct blk_trace *bt,
455                                 struct block_device *bdev)
456 {
457         struct hd_struct *part = NULL;
458
459         if (bdev)
460                 part = bdev->bd_part;
461
462         if (part) {
463                 bt->start_lba = part->start_sect;
464                 bt->end_lba = part->start_sect + part->nr_sects;
465         } else {
466                 bt->start_lba = 0;
467                 bt->end_lba = -1ULL;
468         }
469 }
470
471 /*
472  * Setup everything required to start tracing
473  */
474 static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
475                               struct block_device *bdev,
476                               struct blk_user_trace_setup *buts)
477 {
478         struct blk_trace *bt = NULL;
479         struct dentry *dir = NULL;
480         int ret;
481
482         if (!buts->buf_size || !buts->buf_nr)
483                 return -EINVAL;
484
485         if (!blk_debugfs_root)
486                 return -ENOENT;
487
488         strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
489         buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
490
491         /*
492          * some device names have larger paths - convert the slashes
493          * to underscores for this to work as expected
494          */
495         strreplace(buts->name, '/', '_');
496
497         bt = kzalloc(sizeof(*bt), GFP_KERNEL);
498         if (!bt)
499                 return -ENOMEM;
500
501         ret = -ENOMEM;
502         bt->sequence = alloc_percpu(unsigned long);
503         if (!bt->sequence)
504                 goto err;
505
506         bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
507         if (!bt->msg_data)
508                 goto err;
509
510         ret = -ENOENT;
511
512         dir = debugfs_lookup(buts->name, blk_debugfs_root);
513         if (!dir)
514                 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
515         if (!dir)
516                 goto err;
517
518         bt->dev = dev;
519         atomic_set(&bt->dropped, 0);
520         INIT_LIST_HEAD(&bt->running_list);
521
522         ret = -EIO;
523         bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
524                                                &blk_dropped_fops);
525         if (!bt->dropped_file)
526                 goto err;
527
528         bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
529         if (!bt->msg_file)
530                 goto err;
531
532         bt->rchan = relay_open("trace", dir, buts->buf_size,
533                                 buts->buf_nr, &blk_relay_callbacks, bt);
534         if (!bt->rchan)
535                 goto err;
536
537         bt->act_mask = buts->act_mask;
538         if (!bt->act_mask)
539                 bt->act_mask = (u16) -1;
540
541         blk_trace_setup_lba(bt, bdev);
542
543         /* overwrite with user settings */
544         if (buts->start_lba)
545                 bt->start_lba = buts->start_lba;
546         if (buts->end_lba)
547                 bt->end_lba = buts->end_lba;
548
549         bt->pid = buts->pid;
550         bt->trace_state = Blktrace_setup;
551
552         ret = -EBUSY;
553         if (cmpxchg(&q->blk_trace, NULL, bt))
554                 goto err;
555
556         get_probe_ref();
557
558         ret = 0;
559 err:
560         if (dir && !bt->dir)
561                 dput(dir);
562         if (ret)
563                 blk_trace_free(bt);
564         return ret;
565 }
566
567 static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
568                              struct block_device *bdev, char __user *arg)
569 {
570         struct blk_user_trace_setup buts;
571         int ret;
572
573         ret = copy_from_user(&buts, arg, sizeof(buts));
574         if (ret)
575                 return -EFAULT;
576
577         ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
578         if (ret)
579                 return ret;
580
581         if (copy_to_user(arg, &buts, sizeof(buts))) {
582                 __blk_trace_remove(q);
583                 return -EFAULT;
584         }
585         return 0;
586 }
587
588 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
589                     struct block_device *bdev,
590                     char __user *arg)
591 {
592         int ret;
593
594         mutex_lock(&q->blk_trace_mutex);
595         ret = __blk_trace_setup(q, name, dev, bdev, arg);
596         mutex_unlock(&q->blk_trace_mutex);
597
598         return ret;
599 }
600 EXPORT_SYMBOL_GPL(blk_trace_setup);
601
602 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
603 static int compat_blk_trace_setup(struct request_queue *q, char *name,
604                                   dev_t dev, struct block_device *bdev,
605                                   char __user *arg)
606 {
607         struct blk_user_trace_setup buts;
608         struct compat_blk_user_trace_setup cbuts;
609         int ret;
610
611         if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
612                 return -EFAULT;
613
614         buts = (struct blk_user_trace_setup) {
615                 .act_mask = cbuts.act_mask,
616                 .buf_size = cbuts.buf_size,
617                 .buf_nr = cbuts.buf_nr,
618                 .start_lba = cbuts.start_lba,
619                 .end_lba = cbuts.end_lba,
620                 .pid = cbuts.pid,
621         };
622
623         ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
624         if (ret)
625                 return ret;
626
627         if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
628                 __blk_trace_remove(q);
629                 return -EFAULT;
630         }
631
632         return 0;
633 }
634 #endif
635
636 static int __blk_trace_startstop(struct request_queue *q, int start)
637 {
638         int ret;
639         struct blk_trace *bt = q->blk_trace;
640
641         if (bt == NULL)
642                 return -EINVAL;
643
644         /*
645          * For starting a trace, we can transition from a setup or stopped
646          * trace. For stopping a trace, the state must be running
647          */
648         ret = -EINVAL;
649         if (start) {
650                 if (bt->trace_state == Blktrace_setup ||
651                     bt->trace_state == Blktrace_stopped) {
652                         blktrace_seq++;
653                         smp_mb();
654                         bt->trace_state = Blktrace_running;
655                         spin_lock_irq(&running_trace_lock);
656                         list_add(&bt->running_list, &running_trace_list);
657                         spin_unlock_irq(&running_trace_lock);
658
659                         trace_note_time(bt);
660                         ret = 0;
661                 }
662         } else {
663                 if (bt->trace_state == Blktrace_running) {
664                         bt->trace_state = Blktrace_stopped;
665                         spin_lock_irq(&running_trace_lock);
666                         list_del_init(&bt->running_list);
667                         spin_unlock_irq(&running_trace_lock);
668                         relay_flush(bt->rchan);
669                         ret = 0;
670                 }
671         }
672
673         return ret;
674 }
675
676 int blk_trace_startstop(struct request_queue *q, int start)
677 {
678         int ret;
679
680         mutex_lock(&q->blk_trace_mutex);
681         ret = __blk_trace_startstop(q, start);
682         mutex_unlock(&q->blk_trace_mutex);
683
684         return ret;
685 }
686 EXPORT_SYMBOL_GPL(blk_trace_startstop);
687
688 /*
689  * When reading or writing the blktrace sysfs files, the references to the
690  * opened sysfs or device files should prevent the underlying block device
691  * from being removed. So no further delete protection is really needed.
692  */
693
694 /**
695  * blk_trace_ioctl: - handle the ioctls associated with tracing
696  * @bdev:       the block device
697  * @cmd:        the ioctl cmd
698  * @arg:        the argument data, if any
699  *
700  **/
701 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
702 {
703         struct request_queue *q;
704         int ret, start = 0;
705         char b[BDEVNAME_SIZE];
706
707         q = bdev_get_queue(bdev);
708         if (!q)
709                 return -ENXIO;
710
711         mutex_lock(&q->blk_trace_mutex);
712
713         switch (cmd) {
714         case BLKTRACESETUP:
715                 bdevname(bdev, b);
716                 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
717                 break;
718 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
719         case BLKTRACESETUP32:
720                 bdevname(bdev, b);
721                 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
722                 break;
723 #endif
724         case BLKTRACESTART:
725                 start = 1;
726         case BLKTRACESTOP:
727                 ret = __blk_trace_startstop(q, start);
728                 break;
729         case BLKTRACETEARDOWN:
730                 ret = __blk_trace_remove(q);
731                 break;
732         default:
733                 ret = -ENOTTY;
734                 break;
735         }
736
737         mutex_unlock(&q->blk_trace_mutex);
738         return ret;
739 }
740
741 /**
742  * blk_trace_shutdown: - stop and cleanup trace structures
743  * @q:    the request queue associated with the device
744  *
745  **/
746 void blk_trace_shutdown(struct request_queue *q)
747 {
748         mutex_lock(&q->blk_trace_mutex);
749
750         if (q->blk_trace) {
751                 __blk_trace_startstop(q, 0);
752                 __blk_trace_remove(q);
753         }
754
755         mutex_unlock(&q->blk_trace_mutex);
756 }
757
758 #ifdef CONFIG_BLK_CGROUP
759 static union kernfs_node_id *
760 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
761 {
762         struct blk_trace *bt = q->blk_trace;
763
764         if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
765                 return NULL;
766
767         if (!bio->bi_css)
768                 return NULL;
769         return cgroup_get_kernfs_id(bio->bi_css->cgroup);
770 }
771 #else
772 static union kernfs_node_id *
773 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
774 {
775         return NULL;
776 }
777 #endif
778
779 static union kernfs_node_id *
780 blk_trace_request_get_cgid(struct request_queue *q, struct request *rq)
781 {
782         if (!rq->bio)
783                 return NULL;
784         /* Use the first bio */
785         return blk_trace_bio_get_cgid(q, rq->bio);
786 }
787
788 /*
789  * blktrace probes
790  */
791
792 /**
793  * blk_add_trace_rq - Add a trace for a request oriented action
794  * @rq:         the source request
795  * @error:      return status to log
796  * @nr_bytes:   number of completed bytes
797  * @what:       the action
798  * @cgid:       the cgroup info
799  *
800  * Description:
801  *     Records an action against a request. Will log the bio offset + size.
802  *
803  **/
804 static void blk_add_trace_rq(struct request *rq, int error,
805                              unsigned int nr_bytes, u32 what,
806                              union kernfs_node_id *cgid)
807 {
808         struct blk_trace *bt = rq->q->blk_trace;
809
810         if (likely(!bt))
811                 return;
812
813         if (blk_rq_is_passthrough(rq))
814                 what |= BLK_TC_ACT(BLK_TC_PC);
815         else
816                 what |= BLK_TC_ACT(BLK_TC_FS);
817
818         __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
819                         rq->cmd_flags, what, error, 0, NULL, cgid);
820 }
821
822 static void blk_add_trace_rq_insert(void *ignore,
823                                     struct request_queue *q, struct request *rq)
824 {
825         blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
826                          blk_trace_request_get_cgid(q, rq));
827 }
828
829 static void blk_add_trace_rq_issue(void *ignore,
830                                    struct request_queue *q, struct request *rq)
831 {
832         blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
833                          blk_trace_request_get_cgid(q, rq));
834 }
835
836 static void blk_add_trace_rq_requeue(void *ignore,
837                                      struct request_queue *q,
838                                      struct request *rq)
839 {
840         blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
841                          blk_trace_request_get_cgid(q, rq));
842 }
843
844 static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
845                         int error, unsigned int nr_bytes)
846 {
847         blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
848                          blk_trace_request_get_cgid(rq->q, rq));
849 }
850
851 /**
852  * blk_add_trace_bio - Add a trace for a bio oriented action
853  * @q:          queue the io is for
854  * @bio:        the source bio
855  * @what:       the action
856  * @error:      error, if any
857  *
858  * Description:
859  *     Records an action against a bio. Will log the bio offset + size.
860  *
861  **/
862 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
863                               u32 what, int error)
864 {
865         struct blk_trace *bt = q->blk_trace;
866
867         if (likely(!bt))
868                 return;
869
870         __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
871                         bio_op(bio), bio->bi_opf, what, error, 0, NULL,
872                         blk_trace_bio_get_cgid(q, bio));
873 }
874
875 static void blk_add_trace_bio_bounce(void *ignore,
876                                      struct request_queue *q, struct bio *bio)
877 {
878         blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
879 }
880
881 static void blk_add_trace_bio_complete(void *ignore,
882                                        struct request_queue *q, struct bio *bio,
883                                        int error)
884 {
885         blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
886 }
887
888 static void blk_add_trace_bio_backmerge(void *ignore,
889                                         struct request_queue *q,
890                                         struct request *rq,
891                                         struct bio *bio)
892 {
893         blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
894 }
895
896 static void blk_add_trace_bio_frontmerge(void *ignore,
897                                          struct request_queue *q,
898                                          struct request *rq,
899                                          struct bio *bio)
900 {
901         blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
902 }
903
904 static void blk_add_trace_bio_queue(void *ignore,
905                                     struct request_queue *q, struct bio *bio)
906 {
907         blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
908 }
909
910 static void blk_add_trace_getrq(void *ignore,
911                                 struct request_queue *q,
912                                 struct bio *bio, int rw)
913 {
914         if (bio)
915                 blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
916         else {
917                 struct blk_trace *bt = q->blk_trace;
918
919                 if (bt)
920                         __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
921                                         NULL, NULL);
922         }
923 }
924
925
926 static void blk_add_trace_sleeprq(void *ignore,
927                                   struct request_queue *q,
928                                   struct bio *bio, int rw)
929 {
930         if (bio)
931                 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
932         else {
933                 struct blk_trace *bt = q->blk_trace;
934
935                 if (bt)
936                         __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
937                                         0, 0, NULL, NULL);
938         }
939 }
940
941 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
942 {
943         struct blk_trace *bt = q->blk_trace;
944
945         if (bt)
946                 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, NULL);
947 }
948
949 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
950                                     unsigned int depth, bool explicit)
951 {
952         struct blk_trace *bt = q->blk_trace;
953
954         if (bt) {
955                 __be64 rpdu = cpu_to_be64(depth);
956                 u32 what;
957
958                 if (explicit)
959                         what = BLK_TA_UNPLUG_IO;
960                 else
961                         what = BLK_TA_UNPLUG_TIMER;
962
963                 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, NULL);
964         }
965 }
966
967 static void blk_add_trace_split(void *ignore,
968                                 struct request_queue *q, struct bio *bio,
969                                 unsigned int pdu)
970 {
971         struct blk_trace *bt = q->blk_trace;
972
973         if (bt) {
974                 __be64 rpdu = cpu_to_be64(pdu);
975
976                 __blk_add_trace(bt, bio->bi_iter.bi_sector,
977                                 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
978                                 BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu),
979                                 &rpdu, blk_trace_bio_get_cgid(q, bio));
980         }
981 }
982
983 /**
984  * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
985  * @ignore:     trace callback data parameter (not used)
986  * @q:          queue the io is for
987  * @bio:        the source bio
988  * @dev:        target device
989  * @from:       source sector
990  *
991  * Description:
992  *     Device mapper or raid target sometimes need to split a bio because
993  *     it spans a stripe (or similar). Add a trace for that action.
994  *
995  **/
996 static void blk_add_trace_bio_remap(void *ignore,
997                                     struct request_queue *q, struct bio *bio,
998                                     dev_t dev, sector_t from)
999 {
1000         struct blk_trace *bt = q->blk_trace;
1001         struct blk_io_trace_remap r;
1002
1003         if (likely(!bt))
1004                 return;
1005
1006         r.device_from = cpu_to_be32(dev);
1007         r.device_to   = cpu_to_be32(bio_dev(bio));
1008         r.sector_from = cpu_to_be64(from);
1009
1010         __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1011                         bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status,
1012                         sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1013 }
1014
1015 /**
1016  * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1017  * @ignore:     trace callback data parameter (not used)
1018  * @q:          queue the io is for
1019  * @rq:         the source request
1020  * @dev:        target device
1021  * @from:       source sector
1022  *
1023  * Description:
1024  *     Device mapper remaps request to other devices.
1025  *     Add a trace for that action.
1026  *
1027  **/
1028 static void blk_add_trace_rq_remap(void *ignore,
1029                                    struct request_queue *q,
1030                                    struct request *rq, dev_t dev,
1031                                    sector_t from)
1032 {
1033         struct blk_trace *bt = q->blk_trace;
1034         struct blk_io_trace_remap r;
1035
1036         if (likely(!bt))
1037                 return;
1038
1039         r.device_from = cpu_to_be32(dev);
1040         r.device_to   = cpu_to_be32(disk_devt(rq->rq_disk));
1041         r.sector_from = cpu_to_be64(from);
1042
1043         __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1044                         rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1045                         sizeof(r), &r, blk_trace_request_get_cgid(q, rq));
1046 }
1047
1048 /**
1049  * blk_add_driver_data - Add binary message with driver-specific data
1050  * @q:          queue the io is for
1051  * @rq:         io request
1052  * @data:       driver-specific data
1053  * @len:        length of driver-specific data
1054  *
1055  * Description:
1056  *     Some drivers might want to write driver-specific data per request.
1057  *
1058  **/
1059 void blk_add_driver_data(struct request_queue *q,
1060                          struct request *rq,
1061                          void *data, size_t len)
1062 {
1063         struct blk_trace *bt = q->blk_trace;
1064
1065         if (likely(!bt))
1066                 return;
1067
1068         __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1069                                 BLK_TA_DRV_DATA, 0, len, data,
1070                                 blk_trace_request_get_cgid(q, rq));
1071 }
1072 EXPORT_SYMBOL_GPL(blk_add_driver_data);
1073
1074 static void blk_register_tracepoints(void)
1075 {
1076         int ret;
1077
1078         ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1079         WARN_ON(ret);
1080         ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1081         WARN_ON(ret);
1082         ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1083         WARN_ON(ret);
1084         ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1085         WARN_ON(ret);
1086         ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1087         WARN_ON(ret);
1088         ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1089         WARN_ON(ret);
1090         ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1091         WARN_ON(ret);
1092         ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1093         WARN_ON(ret);
1094         ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1095         WARN_ON(ret);
1096         ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1097         WARN_ON(ret);
1098         ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1099         WARN_ON(ret);
1100         ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1101         WARN_ON(ret);
1102         ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1103         WARN_ON(ret);
1104         ret = register_trace_block_split(blk_add_trace_split, NULL);
1105         WARN_ON(ret);
1106         ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1107         WARN_ON(ret);
1108         ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1109         WARN_ON(ret);
1110 }
1111
1112 static void blk_unregister_tracepoints(void)
1113 {
1114         unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1115         unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1116         unregister_trace_block_split(blk_add_trace_split, NULL);
1117         unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1118         unregister_trace_block_plug(blk_add_trace_plug, NULL);
1119         unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1120         unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1121         unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1122         unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1123         unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1124         unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1125         unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1126         unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1127         unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1128         unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1129         unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1130
1131         tracepoint_synchronize_unregister();
1132 }
1133
1134 /*
1135  * struct blk_io_tracer formatting routines
1136  */
1137
1138 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1139 {
1140         int i = 0;
1141         int tc = t->action >> BLK_TC_SHIFT;
1142
1143         if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1144                 rwbs[i++] = 'N';
1145                 goto out;
1146         }
1147
1148         if (tc & BLK_TC_FLUSH)
1149                 rwbs[i++] = 'F';
1150
1151         if (tc & BLK_TC_DISCARD)
1152                 rwbs[i++] = 'D';
1153         else if (tc & BLK_TC_WRITE)
1154                 rwbs[i++] = 'W';
1155         else if (t->bytes)
1156                 rwbs[i++] = 'R';
1157         else
1158                 rwbs[i++] = 'N';
1159
1160         if (tc & BLK_TC_FUA)
1161                 rwbs[i++] = 'F';
1162         if (tc & BLK_TC_AHEAD)
1163                 rwbs[i++] = 'A';
1164         if (tc & BLK_TC_SYNC)
1165                 rwbs[i++] = 'S';
1166         if (tc & BLK_TC_META)
1167                 rwbs[i++] = 'M';
1168 out:
1169         rwbs[i] = '\0';
1170 }
1171
1172 static inline
1173 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1174 {
1175         return (const struct blk_io_trace *)ent;
1176 }
1177
1178 static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1179 {
1180         return (void *)(te_blk_io_trace(ent) + 1) +
1181                 (has_cg ? sizeof(union kernfs_node_id) : 0);
1182 }
1183
1184 static inline const void *cgid_start(const struct trace_entry *ent)
1185 {
1186         return (void *)(te_blk_io_trace(ent) + 1);
1187 }
1188
1189 static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1190 {
1191         return te_blk_io_trace(ent)->pdu_len -
1192                         (has_cg ? sizeof(union kernfs_node_id) : 0);
1193 }
1194
1195 static inline u32 t_action(const struct trace_entry *ent)
1196 {
1197         return te_blk_io_trace(ent)->action;
1198 }
1199
1200 static inline u32 t_bytes(const struct trace_entry *ent)
1201 {
1202         return te_blk_io_trace(ent)->bytes;
1203 }
1204
1205 static inline u32 t_sec(const struct trace_entry *ent)
1206 {
1207         return te_blk_io_trace(ent)->bytes >> 9;
1208 }
1209
1210 static inline unsigned long long t_sector(const struct trace_entry *ent)
1211 {
1212         return te_blk_io_trace(ent)->sector;
1213 }
1214
1215 static inline __u16 t_error(const struct trace_entry *ent)
1216 {
1217         return te_blk_io_trace(ent)->error;
1218 }
1219
1220 static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1221 {
1222         const __u64 *val = pdu_start(ent, has_cg);
1223         return be64_to_cpu(*val);
1224 }
1225
1226 static void get_pdu_remap(const struct trace_entry *ent,
1227                           struct blk_io_trace_remap *r, bool has_cg)
1228 {
1229         const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1230         __u64 sector_from = __r->sector_from;
1231
1232         r->device_from = be32_to_cpu(__r->device_from);
1233         r->device_to   = be32_to_cpu(__r->device_to);
1234         r->sector_from = be64_to_cpu(sector_from);
1235 }
1236
1237 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1238         bool has_cg);
1239
1240 static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1241         bool has_cg)
1242 {
1243         char rwbs[RWBS_LEN];
1244         unsigned long long ts  = iter->ts;
1245         unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1246         unsigned secs          = (unsigned long)ts;
1247         const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1248
1249         fill_rwbs(rwbs, t);
1250
1251         trace_seq_printf(&iter->seq,
1252                          "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1253                          MAJOR(t->device), MINOR(t->device), iter->cpu,
1254                          secs, nsec_rem, iter->ent->pid, act, rwbs);
1255 }
1256
1257 static void blk_log_action(struct trace_iterator *iter, const char *act,
1258         bool has_cg)
1259 {
1260         char rwbs[RWBS_LEN];
1261         const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1262
1263         fill_rwbs(rwbs, t);
1264         if (has_cg) {
1265                 const union kernfs_node_id *id = cgid_start(iter->ent);
1266
1267                 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1268                         char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1269
1270                         cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1271                                 sizeof(blkcg_name_buf));
1272                         trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1273                                  MAJOR(t->device), MINOR(t->device),
1274                                  blkcg_name_buf, act, rwbs);
1275                 } else
1276                         trace_seq_printf(&iter->seq,
1277                                  "%3d,%-3d %x,%-x %2s %3s ",
1278                                  MAJOR(t->device), MINOR(t->device),
1279                                  id->ino, id->generation, act, rwbs);
1280         } else
1281                 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1282                                  MAJOR(t->device), MINOR(t->device), act, rwbs);
1283 }
1284
1285 static void blk_log_dump_pdu(struct trace_seq *s,
1286         const struct trace_entry *ent, bool has_cg)
1287 {
1288         const unsigned char *pdu_buf;
1289         int pdu_len;
1290         int i, end;
1291
1292         pdu_buf = pdu_start(ent, has_cg);
1293         pdu_len = pdu_real_len(ent, has_cg);
1294
1295         if (!pdu_len)
1296                 return;
1297
1298         /* find the last zero that needs to be printed */
1299         for (end = pdu_len - 1; end >= 0; end--)
1300                 if (pdu_buf[end])
1301                         break;
1302         end++;
1303
1304         trace_seq_putc(s, '(');
1305
1306         for (i = 0; i < pdu_len; i++) {
1307
1308                 trace_seq_printf(s, "%s%02x",
1309                                  i == 0 ? "" : " ", pdu_buf[i]);
1310
1311                 /*
1312                  * stop when the rest is just zeroes and indicate so
1313                  * with a ".." appended
1314                  */
1315                 if (i == end && end != pdu_len - 1) {
1316                         trace_seq_puts(s, " ..) ");
1317                         return;
1318                 }
1319         }
1320
1321         trace_seq_puts(s, ") ");
1322 }
1323
1324 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1325 {
1326         char cmd[TASK_COMM_LEN];
1327
1328         trace_find_cmdline(ent->pid, cmd);
1329
1330         if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1331                 trace_seq_printf(s, "%u ", t_bytes(ent));
1332                 blk_log_dump_pdu(s, ent, has_cg);
1333                 trace_seq_printf(s, "[%s]\n", cmd);
1334         } else {
1335                 if (t_sec(ent))
1336                         trace_seq_printf(s, "%llu + %u [%s]\n",
1337                                                 t_sector(ent), t_sec(ent), cmd);
1338                 else
1339                         trace_seq_printf(s, "[%s]\n", cmd);
1340         }
1341 }
1342
1343 static void blk_log_with_error(struct trace_seq *s,
1344                               const struct trace_entry *ent, bool has_cg)
1345 {
1346         if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1347                 blk_log_dump_pdu(s, ent, has_cg);
1348                 trace_seq_printf(s, "[%d]\n", t_error(ent));
1349         } else {
1350                 if (t_sec(ent))
1351                         trace_seq_printf(s, "%llu + %u [%d]\n",
1352                                          t_sector(ent),
1353                                          t_sec(ent), t_error(ent));
1354                 else
1355                         trace_seq_printf(s, "%llu [%d]\n",
1356                                          t_sector(ent), t_error(ent));
1357         }
1358 }
1359
1360 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1361 {
1362         struct blk_io_trace_remap r = { .device_from = 0, };
1363
1364         get_pdu_remap(ent, &r, has_cg);
1365         trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1366                          t_sector(ent), t_sec(ent),
1367                          MAJOR(r.device_from), MINOR(r.device_from),
1368                          (unsigned long long)r.sector_from);
1369 }
1370
1371 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1372 {
1373         char cmd[TASK_COMM_LEN];
1374
1375         trace_find_cmdline(ent->pid, cmd);
1376
1377         trace_seq_printf(s, "[%s]\n", cmd);
1378 }
1379
1380 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1381 {
1382         char cmd[TASK_COMM_LEN];
1383
1384         trace_find_cmdline(ent->pid, cmd);
1385
1386         trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1387 }
1388
1389 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1390 {
1391         char cmd[TASK_COMM_LEN];
1392
1393         trace_find_cmdline(ent->pid, cmd);
1394
1395         trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1396                          get_pdu_int(ent, has_cg), cmd);
1397 }
1398
1399 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1400                         bool has_cg)
1401 {
1402
1403         trace_seq_putmem(s, pdu_start(ent, has_cg),
1404                 pdu_real_len(ent, has_cg));
1405         trace_seq_putc(s, '\n');
1406 }
1407
1408 /*
1409  * struct tracer operations
1410  */
1411
1412 static void blk_tracer_print_header(struct seq_file *m)
1413 {
1414         if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1415                 return;
1416         seq_puts(m, "# DEV   CPU TIMESTAMP     PID ACT FLG\n"
1417                     "#  |     |     |           |   |   |\n");
1418 }
1419
1420 static void blk_tracer_start(struct trace_array *tr)
1421 {
1422         blk_tracer_enabled = true;
1423 }
1424
1425 static int blk_tracer_init(struct trace_array *tr)
1426 {
1427         blk_tr = tr;
1428         blk_tracer_start(tr);
1429         return 0;
1430 }
1431
1432 static void blk_tracer_stop(struct trace_array *tr)
1433 {
1434         blk_tracer_enabled = false;
1435 }
1436
1437 static void blk_tracer_reset(struct trace_array *tr)
1438 {
1439         blk_tracer_stop(tr);
1440 }
1441
1442 static const struct {
1443         const char *act[2];
1444         void       (*print)(struct trace_seq *s, const struct trace_entry *ent,
1445                             bool has_cg);
1446 } what2act[] = {
1447         [__BLK_TA_QUEUE]        = {{  "Q", "queue" },      blk_log_generic },
1448         [__BLK_TA_BACKMERGE]    = {{  "M", "backmerge" },  blk_log_generic },
1449         [__BLK_TA_FRONTMERGE]   = {{  "F", "frontmerge" }, blk_log_generic },
1450         [__BLK_TA_GETRQ]        = {{  "G", "getrq" },      blk_log_generic },
1451         [__BLK_TA_SLEEPRQ]      = {{  "S", "sleeprq" },    blk_log_generic },
1452         [__BLK_TA_REQUEUE]      = {{  "R", "requeue" },    blk_log_with_error },
1453         [__BLK_TA_ISSUE]        = {{  "D", "issue" },      blk_log_generic },
1454         [__BLK_TA_COMPLETE]     = {{  "C", "complete" },   blk_log_with_error },
1455         [__BLK_TA_PLUG]         = {{  "P", "plug" },       blk_log_plug },
1456         [__BLK_TA_UNPLUG_IO]    = {{  "U", "unplug_io" },  blk_log_unplug },
1457         [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1458         [__BLK_TA_INSERT]       = {{  "I", "insert" },     blk_log_generic },
1459         [__BLK_TA_SPLIT]        = {{  "X", "split" },      blk_log_split },
1460         [__BLK_TA_BOUNCE]       = {{  "B", "bounce" },     blk_log_generic },
1461         [__BLK_TA_REMAP]        = {{  "A", "remap" },      blk_log_remap },
1462 };
1463
1464 static enum print_line_t print_one_line(struct trace_iterator *iter,
1465                                         bool classic)
1466 {
1467         struct trace_array *tr = iter->tr;
1468         struct trace_seq *s = &iter->seq;
1469         const struct blk_io_trace *t;
1470         u16 what;
1471         bool long_act;
1472         blk_log_action_t *log_action;
1473         bool has_cg;
1474
1475         t          = te_blk_io_trace(iter->ent);
1476         what       = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1477         long_act   = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1478         log_action = classic ? &blk_log_action_classic : &blk_log_action;
1479         has_cg     = t->action & __BLK_TA_CGROUP;
1480
1481         if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1482                 log_action(iter, long_act ? "message" : "m", has_cg);
1483                 blk_log_msg(s, iter->ent, has_cg);
1484                 return trace_handle_return(s);
1485         }
1486
1487         if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1488                 trace_seq_printf(s, "Unknown action %x\n", what);
1489         else {
1490                 log_action(iter, what2act[what].act[long_act], has_cg);
1491                 what2act[what].print(s, iter->ent, has_cg);
1492         }
1493
1494         return trace_handle_return(s);
1495 }
1496
1497 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1498                                                int flags, struct trace_event *event)
1499 {
1500         return print_one_line(iter, false);
1501 }
1502
1503 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1504 {
1505         struct trace_seq *s = &iter->seq;
1506         struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1507         const int offset = offsetof(struct blk_io_trace, sector);
1508         struct blk_io_trace old = {
1509                 .magic    = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1510                 .time     = iter->ts,
1511         };
1512
1513         trace_seq_putmem(s, &old, offset);
1514         trace_seq_putmem(s, &t->sector,
1515                          sizeof(old) - offset + t->pdu_len);
1516 }
1517
1518 static enum print_line_t
1519 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1520                              struct trace_event *event)
1521 {
1522         blk_trace_synthesize_old_trace(iter);
1523
1524         return trace_handle_return(&iter->seq);
1525 }
1526
1527 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1528 {
1529         if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1530                 return TRACE_TYPE_UNHANDLED;
1531
1532         return print_one_line(iter, true);
1533 }
1534
1535 static int
1536 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1537 {
1538         /* don't output context-info for blk_classic output */
1539         if (bit == TRACE_BLK_OPT_CLASSIC) {
1540                 if (set)
1541                         tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1542                 else
1543                         tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1544         }
1545         return 0;
1546 }
1547
1548 static struct tracer blk_tracer __read_mostly = {
1549         .name           = "blk",
1550         .init           = blk_tracer_init,
1551         .reset          = blk_tracer_reset,
1552         .start          = blk_tracer_start,
1553         .stop           = blk_tracer_stop,
1554         .print_header   = blk_tracer_print_header,
1555         .print_line     = blk_tracer_print_line,
1556         .flags          = &blk_tracer_flags,
1557         .set_flag       = blk_tracer_set_flag,
1558 };
1559
1560 static struct trace_event_functions trace_blk_event_funcs = {
1561         .trace          = blk_trace_event_print,
1562         .binary         = blk_trace_event_print_binary,
1563 };
1564
1565 static struct trace_event trace_blk_event = {
1566         .type           = TRACE_BLK,
1567         .funcs          = &trace_blk_event_funcs,
1568 };
1569
1570 static int __init init_blk_tracer(void)
1571 {
1572         if (!register_trace_event(&trace_blk_event)) {
1573                 pr_warn("Warning: could not register block events\n");
1574                 return 1;
1575         }
1576
1577         if (register_tracer(&blk_tracer) != 0) {
1578                 pr_warn("Warning: could not register the block tracer\n");
1579                 unregister_trace_event(&trace_blk_event);
1580                 return 1;
1581         }
1582
1583         return 0;
1584 }
1585
1586 device_initcall(init_blk_tracer);
1587
1588 static int blk_trace_remove_queue(struct request_queue *q)
1589 {
1590         struct blk_trace *bt;
1591
1592         bt = xchg(&q->blk_trace, NULL);
1593         if (bt == NULL)
1594                 return -EINVAL;
1595
1596         put_probe_ref();
1597         blk_trace_free(bt);
1598         return 0;
1599 }
1600
1601 /*
1602  * Setup everything required to start tracing
1603  */
1604 static int blk_trace_setup_queue(struct request_queue *q,
1605                                  struct block_device *bdev)
1606 {
1607         struct blk_trace *bt = NULL;
1608         int ret = -ENOMEM;
1609
1610         bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1611         if (!bt)
1612                 return -ENOMEM;
1613
1614         bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1615         if (!bt->msg_data)
1616                 goto free_bt;
1617
1618         bt->dev = bdev->bd_dev;
1619         bt->act_mask = (u16)-1;
1620
1621         blk_trace_setup_lba(bt, bdev);
1622
1623         ret = -EBUSY;
1624         if (cmpxchg(&q->blk_trace, NULL, bt))
1625                 goto free_bt;
1626
1627         get_probe_ref();
1628         return 0;
1629
1630 free_bt:
1631         blk_trace_free(bt);
1632         return ret;
1633 }
1634
1635 /*
1636  * sysfs interface to enable and configure tracing
1637  */
1638
1639 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1640                                          struct device_attribute *attr,
1641                                          char *buf);
1642 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1643                                           struct device_attribute *attr,
1644                                           const char *buf, size_t count);
1645 #define BLK_TRACE_DEVICE_ATTR(_name) \
1646         DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1647                     sysfs_blk_trace_attr_show, \
1648                     sysfs_blk_trace_attr_store)
1649
1650 static BLK_TRACE_DEVICE_ATTR(enable);
1651 static BLK_TRACE_DEVICE_ATTR(act_mask);
1652 static BLK_TRACE_DEVICE_ATTR(pid);
1653 static BLK_TRACE_DEVICE_ATTR(start_lba);
1654 static BLK_TRACE_DEVICE_ATTR(end_lba);
1655
1656 static struct attribute *blk_trace_attrs[] = {
1657         &dev_attr_enable.attr,
1658         &dev_attr_act_mask.attr,
1659         &dev_attr_pid.attr,
1660         &dev_attr_start_lba.attr,
1661         &dev_attr_end_lba.attr,
1662         NULL
1663 };
1664
1665 struct attribute_group blk_trace_attr_group = {
1666         .name  = "trace",
1667         .attrs = blk_trace_attrs,
1668 };
1669
1670 static const struct {
1671         int mask;
1672         const char *str;
1673 } mask_maps[] = {
1674         { BLK_TC_READ,          "read"          },
1675         { BLK_TC_WRITE,         "write"         },
1676         { BLK_TC_FLUSH,         "flush"         },
1677         { BLK_TC_SYNC,          "sync"          },
1678         { BLK_TC_QUEUE,         "queue"         },
1679         { BLK_TC_REQUEUE,       "requeue"       },
1680         { BLK_TC_ISSUE,         "issue"         },
1681         { BLK_TC_COMPLETE,      "complete"      },
1682         { BLK_TC_FS,            "fs"            },
1683         { BLK_TC_PC,            "pc"            },
1684         { BLK_TC_NOTIFY,        "notify"        },
1685         { BLK_TC_AHEAD,         "ahead"         },
1686         { BLK_TC_META,          "meta"          },
1687         { BLK_TC_DISCARD,       "discard"       },
1688         { BLK_TC_DRV_DATA,      "drv_data"      },
1689         { BLK_TC_FUA,           "fua"           },
1690 };
1691
1692 static int blk_trace_str2mask(const char *str)
1693 {
1694         int i;
1695         int mask = 0;
1696         char *buf, *s, *token;
1697
1698         buf = kstrdup(str, GFP_KERNEL);
1699         if (buf == NULL)
1700                 return -ENOMEM;
1701         s = strstrip(buf);
1702
1703         while (1) {
1704                 token = strsep(&s, ",");
1705                 if (token == NULL)
1706                         break;
1707
1708                 if (*token == '\0')
1709                         continue;
1710
1711                 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1712                         if (strcasecmp(token, mask_maps[i].str) == 0) {
1713                                 mask |= mask_maps[i].mask;
1714                                 break;
1715                         }
1716                 }
1717                 if (i == ARRAY_SIZE(mask_maps)) {
1718                         mask = -EINVAL;
1719                         break;
1720                 }
1721         }
1722         kfree(buf);
1723
1724         return mask;
1725 }
1726
1727 static ssize_t blk_trace_mask2str(char *buf, int mask)
1728 {
1729         int i;
1730         char *p = buf;
1731
1732         for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1733                 if (mask & mask_maps[i].mask) {
1734                         p += sprintf(p, "%s%s",
1735                                     (p == buf) ? "" : ",", mask_maps[i].str);
1736                 }
1737         }
1738         *p++ = '\n';
1739
1740         return p - buf;
1741 }
1742
1743 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1744 {
1745         if (bdev->bd_disk == NULL)
1746                 return NULL;
1747
1748         return bdev_get_queue(bdev);
1749 }
1750
1751 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1752                                          struct device_attribute *attr,
1753                                          char *buf)
1754 {
1755         struct hd_struct *p = dev_to_part(dev);
1756         struct request_queue *q;
1757         struct block_device *bdev;
1758         ssize_t ret = -ENXIO;
1759
1760         bdev = bdget(part_devt(p));
1761         if (bdev == NULL)
1762                 goto out;
1763
1764         q = blk_trace_get_queue(bdev);
1765         if (q == NULL)
1766                 goto out_bdput;
1767
1768         mutex_lock(&q->blk_trace_mutex);
1769
1770         if (attr == &dev_attr_enable) {
1771                 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1772                 goto out_unlock_bdev;
1773         }
1774
1775         if (q->blk_trace == NULL)
1776                 ret = sprintf(buf, "disabled\n");
1777         else if (attr == &dev_attr_act_mask)
1778                 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1779         else if (attr == &dev_attr_pid)
1780                 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1781         else if (attr == &dev_attr_start_lba)
1782                 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1783         else if (attr == &dev_attr_end_lba)
1784                 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1785
1786 out_unlock_bdev:
1787         mutex_unlock(&q->blk_trace_mutex);
1788 out_bdput:
1789         bdput(bdev);
1790 out:
1791         return ret;
1792 }
1793
1794 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1795                                           struct device_attribute *attr,
1796                                           const char *buf, size_t count)
1797 {
1798         struct block_device *bdev;
1799         struct request_queue *q;
1800         struct hd_struct *p;
1801         u64 value;
1802         ssize_t ret = -EINVAL;
1803
1804         if (count == 0)
1805                 goto out;
1806
1807         if (attr == &dev_attr_act_mask) {
1808                 if (kstrtoull(buf, 0, &value)) {
1809                         /* Assume it is a list of trace category names */
1810                         ret = blk_trace_str2mask(buf);
1811                         if (ret < 0)
1812                                 goto out;
1813                         value = ret;
1814                 }
1815         } else if (kstrtoull(buf, 0, &value))
1816                 goto out;
1817
1818         ret = -ENXIO;
1819
1820         p = dev_to_part(dev);
1821         bdev = bdget(part_devt(p));
1822         if (bdev == NULL)
1823                 goto out;
1824
1825         q = blk_trace_get_queue(bdev);
1826         if (q == NULL)
1827                 goto out_bdput;
1828
1829         mutex_lock(&q->blk_trace_mutex);
1830
1831         if (attr == &dev_attr_enable) {
1832                 if (!!value == !!q->blk_trace) {
1833                         ret = 0;
1834                         goto out_unlock_bdev;
1835                 }
1836                 if (value)
1837                         ret = blk_trace_setup_queue(q, bdev);
1838                 else
1839                         ret = blk_trace_remove_queue(q);
1840                 goto out_unlock_bdev;
1841         }
1842
1843         ret = 0;
1844         if (q->blk_trace == NULL)
1845                 ret = blk_trace_setup_queue(q, bdev);
1846
1847         if (ret == 0) {
1848                 if (attr == &dev_attr_act_mask)
1849                         q->blk_trace->act_mask = value;
1850                 else if (attr == &dev_attr_pid)
1851                         q->blk_trace->pid = value;
1852                 else if (attr == &dev_attr_start_lba)
1853                         q->blk_trace->start_lba = value;
1854                 else if (attr == &dev_attr_end_lba)
1855                         q->blk_trace->end_lba = value;
1856         }
1857
1858 out_unlock_bdev:
1859         mutex_unlock(&q->blk_trace_mutex);
1860 out_bdput:
1861         bdput(bdev);
1862 out:
1863         return ret ? ret : count;
1864 }
1865
1866 int blk_trace_init_sysfs(struct device *dev)
1867 {
1868         return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1869 }
1870
1871 void blk_trace_remove_sysfs(struct device *dev)
1872 {
1873         sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1874 }
1875
1876 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1877
1878 #ifdef CONFIG_EVENT_TRACING
1879
1880 void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
1881 {
1882         int i = 0;
1883
1884         if (op & REQ_PREFLUSH)
1885                 rwbs[i++] = 'F';
1886
1887         switch (op & REQ_OP_MASK) {
1888         case REQ_OP_WRITE:
1889         case REQ_OP_WRITE_SAME:
1890                 rwbs[i++] = 'W';
1891                 break;
1892         case REQ_OP_DISCARD:
1893                 rwbs[i++] = 'D';
1894                 break;
1895         case REQ_OP_SECURE_ERASE:
1896                 rwbs[i++] = 'D';
1897                 rwbs[i++] = 'E';
1898                 break;
1899         case REQ_OP_FLUSH:
1900                 rwbs[i++] = 'F';
1901                 break;
1902         case REQ_OP_READ:
1903                 rwbs[i++] = 'R';
1904                 break;
1905         default:
1906                 rwbs[i++] = 'N';
1907         }
1908
1909         if (op & REQ_FUA)
1910                 rwbs[i++] = 'F';
1911         if (op & REQ_RAHEAD)
1912                 rwbs[i++] = 'A';
1913         if (op & REQ_SYNC)
1914                 rwbs[i++] = 'S';
1915         if (op & REQ_META)
1916                 rwbs[i++] = 'M';
1917
1918         rwbs[i] = '\0';
1919 }
1920 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1921
1922 #endif /* CONFIG_EVENT_TRACING */
1923