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1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/errno.h>
3#include <linux/numa.h>
4#include <linux/slab.h>
5#include <linux/rculist.h>
6#include <linux/threads.h>
7#include <linux/preempt.h>
8#include <linux/irqflags.h>
9#include <linux/vmalloc.h>
10#include <linux/mm.h>
11#include <linux/module.h>
12#include <linux/device-mapper.h>
13
14#include "dm-core.h"
15#include "dm-stats.h"
16
17#define DM_MSG_PREFIX "stats"
18
19static int dm_stat_need_rcu_barrier;
20
21/*
22 * Using 64-bit values to avoid overflow (which is a
23 * problem that block/genhd.c's IO accounting has).
24 */
25struct dm_stat_percpu {
26 unsigned long long sectors[2];
27 unsigned long long ios[2];
28 unsigned long long merges[2];
29 unsigned long long ticks[2];
30 unsigned long long io_ticks[2];
31 unsigned long long io_ticks_total;
32 unsigned long long time_in_queue;
33 unsigned long long *histogram;
34};
35
36struct dm_stat_shared {
37 atomic_t in_flight[2];
38 unsigned long long stamp;
39 struct dm_stat_percpu tmp;
40};
41
42struct dm_stat {
43 struct list_head list_entry;
44 int id;
45 unsigned int stat_flags;
46 size_t n_entries;
47 sector_t start;
48 sector_t end;
49 sector_t step;
50 unsigned int n_histogram_entries;
51 unsigned long long *histogram_boundaries;
52 const char *program_id;
53 const char *aux_data;
54 struct rcu_head rcu_head;
55 size_t shared_alloc_size;
56 size_t percpu_alloc_size;
57 size_t histogram_alloc_size;
58 struct dm_stat_percpu *stat_percpu[NR_CPUS];
59 struct dm_stat_shared stat_shared[] __counted_by(n_entries);
60};
61
62#define STAT_PRECISE_TIMESTAMPS 1
63
64struct dm_stats_last_position {
65 sector_t last_sector;
66 unsigned int last_rw;
67};
68
69#define DM_STAT_MAX_ENTRIES 8388608
70#define DM_STAT_MAX_HISTOGRAM_ENTRIES 134217728
71
72/*
73 * A typo on the command line could possibly make the kernel run out of memory
74 * and crash. To prevent the crash we account all used memory. We fail if we
75 * exhaust 1/4 of all memory or 1/2 of vmalloc space.
76 */
77#define DM_STATS_MEMORY_FACTOR 4
78#define DM_STATS_VMALLOC_FACTOR 2
79
80static DEFINE_SPINLOCK(shared_memory_lock);
81
82static unsigned long shared_memory_amount;
83
84static bool __check_shared_memory(size_t alloc_size)
85{
86 size_t a;
87
88 a = shared_memory_amount + alloc_size;
89 if (a < shared_memory_amount)
90 return false;
91 if (a >> PAGE_SHIFT > totalram_pages() / DM_STATS_MEMORY_FACTOR)
92 return false;
93#ifdef CONFIG_MMU
94 if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR)
95 return false;
96#endif
97 return true;
98}
99
100static bool check_shared_memory(size_t alloc_size)
101{
102 bool ret;
103
104 spin_lock_irq(&shared_memory_lock);
105
106 ret = __check_shared_memory(alloc_size);
107
108 spin_unlock_irq(&shared_memory_lock);
109
110 return ret;
111}
112
113static bool claim_shared_memory(size_t alloc_size)
114{
115 spin_lock_irq(&shared_memory_lock);
116
117 if (!__check_shared_memory(alloc_size)) {
118 spin_unlock_irq(&shared_memory_lock);
119 return false;
120 }
121
122 shared_memory_amount += alloc_size;
123
124 spin_unlock_irq(&shared_memory_lock);
125
126 return true;
127}
128
129static void free_shared_memory(size_t alloc_size)
130{
131 unsigned long flags;
132
133 spin_lock_irqsave(&shared_memory_lock, flags);
134
135 if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) {
136 spin_unlock_irqrestore(&shared_memory_lock, flags);
137 DMCRIT("Memory usage accounting bug.");
138 return;
139 }
140
141 shared_memory_amount -= alloc_size;
142
143 spin_unlock_irqrestore(&shared_memory_lock, flags);
144}
145
146static void *dm_kvzalloc(size_t alloc_size, int node)
147{
148 void *p;
149
150 if (!claim_shared_memory(alloc_size))
151 return NULL;
152
153 p = kvzalloc_node(alloc_size, GFP_KERNEL | __GFP_NOMEMALLOC, node);
154 if (p)
155 return p;
156
157 free_shared_memory(alloc_size);
158
159 return NULL;
160}
161
162static void dm_kvfree(void *ptr, size_t alloc_size)
163{
164 if (!ptr)
165 return;
166
167 free_shared_memory(alloc_size);
168
169 kvfree(ptr);
170}
171
172static void dm_stat_free(struct rcu_head *head)
173{
174 int cpu;
175 struct dm_stat *s = container_of(head, struct dm_stat, rcu_head);
176
177 kfree(s->histogram_boundaries);
178 kfree(s->program_id);
179 kfree(s->aux_data);
180 for_each_possible_cpu(cpu) {
181 if (s->stat_percpu[cpu]) {
182 dm_kvfree(s->stat_percpu[cpu][0].histogram, s->histogram_alloc_size);
183 dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size);
184 }
185 }
186 dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size);
187 dm_kvfree(s, s->shared_alloc_size);
188}
189
190static int dm_stat_in_flight(struct dm_stat_shared *shared)
191{
192 return atomic_read(&shared->in_flight[READ]) +
193 atomic_read(&shared->in_flight[WRITE]);
194}
195
196int dm_stats_init(struct dm_stats *stats)
197{
198 int cpu;
199 struct dm_stats_last_position *last;
200
201 mutex_init(&stats->mutex);
202 INIT_LIST_HEAD(&stats->list);
203 stats->precise_timestamps = false;
204 stats->last = alloc_percpu(struct dm_stats_last_position);
205 if (!stats->last)
206 return -ENOMEM;
207
208 for_each_possible_cpu(cpu) {
209 last = per_cpu_ptr(stats->last, cpu);
210 last->last_sector = (sector_t)ULLONG_MAX;
211 last->last_rw = UINT_MAX;
212 }
213
214 return 0;
215}
216
217void dm_stats_cleanup(struct dm_stats *stats)
218{
219 size_t ni;
220 struct dm_stat *s;
221 struct dm_stat_shared *shared;
222
223 while (!list_empty(&stats->list)) {
224 s = container_of(stats->list.next, struct dm_stat, list_entry);
225 list_del(&s->list_entry);
226 for (ni = 0; ni < s->n_entries; ni++) {
227 shared = &s->stat_shared[ni];
228 if (WARN_ON(dm_stat_in_flight(shared))) {
229 DMCRIT("leaked in-flight counter at index %lu "
230 "(start %llu, end %llu, step %llu): reads %d, writes %d",
231 (unsigned long)ni,
232 (unsigned long long)s->start,
233 (unsigned long long)s->end,
234 (unsigned long long)s->step,
235 atomic_read(&shared->in_flight[READ]),
236 atomic_read(&shared->in_flight[WRITE]));
237 }
238 cond_resched();
239 }
240 dm_stat_free(&s->rcu_head);
241 }
242 free_percpu(stats->last);
243 mutex_destroy(&stats->mutex);
244}
245
246static void dm_stats_recalc_precise_timestamps(struct dm_stats *stats)
247{
248 struct list_head *l;
249 struct dm_stat *tmp_s;
250 bool precise_timestamps = false;
251
252 list_for_each(l, &stats->list) {
253 tmp_s = container_of(l, struct dm_stat, list_entry);
254 if (tmp_s->stat_flags & STAT_PRECISE_TIMESTAMPS) {
255 precise_timestamps = true;
256 break;
257 }
258 }
259 stats->precise_timestamps = precise_timestamps;
260}
261
262static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
263 sector_t step, unsigned int stat_flags,
264 unsigned int n_histogram_entries,
265 unsigned long long *histogram_boundaries,
266 const char *program_id, const char *aux_data,
267 void (*suspend_callback)(struct mapped_device *),
268 void (*resume_callback)(struct mapped_device *),
269 struct mapped_device *md)
270{
271 struct list_head *l;
272 struct dm_stat *s, *tmp_s;
273 sector_t n_entries;
274 size_t ni;
275 size_t shared_alloc_size;
276 size_t percpu_alloc_size;
277 size_t histogram_alloc_size;
278 struct dm_stat_percpu *p;
279 int cpu;
280 int ret_id;
281 int r;
282
283 if (end < start || !step)
284 return -EINVAL;
285
286 n_entries = end - start;
287 if (dm_sector_div64(n_entries, step))
288 n_entries++;
289
290 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
291 return -EOVERFLOW;
292
293 if (n_entries > DM_STAT_MAX_ENTRIES)
294 return -EOVERFLOW;
295
296 shared_alloc_size = struct_size(s, stat_shared, n_entries);
297 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
298 return -EOVERFLOW;
299
300 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
301 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
302 return -EOVERFLOW;
303
304 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
305 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
306 return -EOVERFLOW;
307
308 if ((n_histogram_entries + 1) * (size_t)n_entries > DM_STAT_MAX_HISTOGRAM_ENTRIES)
309 return -EOVERFLOW;
310
311 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +
312 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
313 return -ENOMEM;
314
315 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
316 if (!s)
317 return -ENOMEM;
318
319 s->stat_flags = stat_flags;
320 s->n_entries = n_entries;
321 s->start = start;
322 s->end = end;
323 s->step = step;
324 s->shared_alloc_size = shared_alloc_size;
325 s->percpu_alloc_size = percpu_alloc_size;
326 s->histogram_alloc_size = histogram_alloc_size;
327
328 s->n_histogram_entries = n_histogram_entries;
329 s->histogram_boundaries = kmemdup(histogram_boundaries,
330 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
331 if (!s->histogram_boundaries) {
332 r = -ENOMEM;
333 goto out;
334 }
335
336 s->program_id = kstrdup(program_id, GFP_KERNEL);
337 if (!s->program_id) {
338 r = -ENOMEM;
339 goto out;
340 }
341 s->aux_data = kstrdup(aux_data, GFP_KERNEL);
342 if (!s->aux_data) {
343 r = -ENOMEM;
344 goto out;
345 }
346
347 for (ni = 0; ni < n_entries; ni++) {
348 atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
349 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);
350 cond_resched();
351 }
352
353 if (s->n_histogram_entries) {
354 unsigned long long *hi;
355
356 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE);
357 if (!hi) {
358 r = -ENOMEM;
359 goto out;
360 }
361 for (ni = 0; ni < n_entries; ni++) {
362 s->stat_shared[ni].tmp.histogram = hi;
363 hi += s->n_histogram_entries + 1;
364 cond_resched();
365 }
366 }
367
368 for_each_possible_cpu(cpu) {
369 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
370 if (!p) {
371 r = -ENOMEM;
372 goto out;
373 }
374 s->stat_percpu[cpu] = p;
375 if (s->n_histogram_entries) {
376 unsigned long long *hi;
377
378 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu));
379 if (!hi) {
380 r = -ENOMEM;
381 goto out;
382 }
383 for (ni = 0; ni < n_entries; ni++) {
384 p[ni].histogram = hi;
385 hi += s->n_histogram_entries + 1;
386 cond_resched();
387 }
388 }
389 }
390
391 /*
392 * Suspend/resume to make sure there is no i/o in flight,
393 * so that newly created statistics will be exact.
394 *
395 * (note: we couldn't suspend earlier because we must not
396 * allocate memory while suspended)
397 */
398 suspend_callback(md);
399
400 mutex_lock(&stats->mutex);
401 s->id = 0;
402 list_for_each(l, &stats->list) {
403 tmp_s = container_of(l, struct dm_stat, list_entry);
404 if (WARN_ON(tmp_s->id < s->id)) {
405 r = -EINVAL;
406 goto out_unlock_resume;
407 }
408 if (tmp_s->id > s->id)
409 break;
410 if (unlikely(s->id == INT_MAX)) {
411 r = -ENFILE;
412 goto out_unlock_resume;
413 }
414 s->id++;
415 }
416 ret_id = s->id;
417 list_add_tail_rcu(&s->list_entry, l);
418
419 dm_stats_recalc_precise_timestamps(stats);
420
421 if (!static_key_enabled(&stats_enabled.key))
422 static_branch_enable(&stats_enabled);
423
424 mutex_unlock(&stats->mutex);
425
426 resume_callback(md);
427
428 return ret_id;
429
430out_unlock_resume:
431 mutex_unlock(&stats->mutex);
432 resume_callback(md);
433out:
434 dm_stat_free(&s->rcu_head);
435 return r;
436}
437
438static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
439{
440 struct dm_stat *s;
441
442 list_for_each_entry(s, &stats->list, list_entry) {
443 if (s->id > id)
444 break;
445 if (s->id == id)
446 return s;
447 }
448
449 return NULL;
450}
451
452static int dm_stats_delete(struct dm_stats *stats, int id)
453{
454 struct dm_stat *s;
455 int cpu;
456
457 mutex_lock(&stats->mutex);
458
459 s = __dm_stats_find(stats, id);
460 if (!s) {
461 mutex_unlock(&stats->mutex);
462 return -ENOENT;
463 }
464
465 list_del_rcu(&s->list_entry);
466
467 dm_stats_recalc_precise_timestamps(stats);
468
469 mutex_unlock(&stats->mutex);
470
471 /*
472 * vfree can't be called from RCU callback
473 */
474 for_each_possible_cpu(cpu)
475 if (is_vmalloc_addr(s->stat_percpu) ||
476 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))
477 goto do_sync_free;
478 if (is_vmalloc_addr(s) ||
479 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {
480do_sync_free:
481 synchronize_rcu_expedited();
482 dm_stat_free(&s->rcu_head);
483 } else {
484 WRITE_ONCE(dm_stat_need_rcu_barrier, 1);
485 call_rcu(&s->rcu_head, dm_stat_free);
486 }
487 return 0;
488}
489
490static int dm_stats_list(struct dm_stats *stats, const char *program,
491 char *result, unsigned int maxlen)
492{
493 struct dm_stat *s;
494 sector_t len;
495 unsigned int sz = 0;
496
497 /*
498 * Output format:
499 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
500 */
501
502 mutex_lock(&stats->mutex);
503 list_for_each_entry(s, &stats->list, list_entry) {
504 if (!program || !strcmp(program, s->program_id)) {
505 len = s->end - s->start;
506 DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
507 (unsigned long long)s->start,
508 (unsigned long long)len,
509 (unsigned long long)s->step,
510 s->program_id,
511 s->aux_data);
512 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
513 DMEMIT(" precise_timestamps");
514 if (s->n_histogram_entries) {
515 unsigned int i;
516
517 DMEMIT(" histogram:");
518 for (i = 0; i < s->n_histogram_entries; i++) {
519 if (i)
520 DMEMIT(",");
521 DMEMIT("%llu", s->histogram_boundaries[i]);
522 }
523 }
524 DMEMIT("\n");
525 }
526 cond_resched();
527 }
528 mutex_unlock(&stats->mutex);
529
530 return 1;
531}
532
533static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
534 struct dm_stat_percpu *p)
535{
536 /*
537 * This is racy, but so is part_round_stats_single.
538 */
539 unsigned long long now, difference;
540 unsigned int in_flight_read, in_flight_write;
541
542 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
543 now = jiffies;
544 else
545 now = ktime_to_ns(ktime_get());
546
547 difference = now - shared->stamp;
548 if (!difference)
549 return;
550
551 in_flight_read = (unsigned int)atomic_read(&shared->in_flight[READ]);
552 in_flight_write = (unsigned int)atomic_read(&shared->in_flight[WRITE]);
553 if (in_flight_read)
554 p->io_ticks[READ] += difference;
555 if (in_flight_write)
556 p->io_ticks[WRITE] += difference;
557 if (in_flight_read + in_flight_write) {
558 p->io_ticks_total += difference;
559 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
560 }
561 shared->stamp = now;
562}
563
564static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
565 int idx, sector_t len,
566 struct dm_stats_aux *stats_aux, bool end,
567 unsigned long duration_jiffies)
568{
569 struct dm_stat_shared *shared = &s->stat_shared[entry];
570 struct dm_stat_percpu *p;
571
572 /*
573 * For strict correctness we should use local_irq_save/restore
574 * instead of preempt_disable/enable.
575 *
576 * preempt_disable/enable is racy if the driver finishes bios
577 * from non-interrupt context as well as from interrupt context
578 * or from more different interrupts.
579 *
580 * On 64-bit architectures the race only results in not counting some
581 * events, so it is acceptable. On 32-bit architectures the race could
582 * cause the counter going off by 2^32, so we need to do proper locking
583 * there.
584 *
585 * part_stat_lock()/part_stat_unlock() have this race too.
586 */
587#if BITS_PER_LONG == 32
588 unsigned long flags;
589
590 local_irq_save(flags);
591#else
592 preempt_disable();
593#endif
594 p = &s->stat_percpu[smp_processor_id()][entry];
595
596 if (!end) {
597 dm_stat_round(s, shared, p);
598 atomic_inc(&shared->in_flight[idx]);
599 } else {
600 unsigned long long duration;
601
602 dm_stat_round(s, shared, p);
603 atomic_dec(&shared->in_flight[idx]);
604 p->sectors[idx] += len;
605 p->ios[idx] += 1;
606 p->merges[idx] += stats_aux->merged;
607 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
608 p->ticks[idx] += duration_jiffies;
609 duration = jiffies_to_msecs(duration_jiffies);
610 } else {
611 p->ticks[idx] += stats_aux->duration_ns;
612 duration = stats_aux->duration_ns;
613 }
614 if (s->n_histogram_entries) {
615 unsigned int lo = 0, hi = s->n_histogram_entries + 1;
616
617 while (lo + 1 < hi) {
618 unsigned int mid = (lo + hi) / 2;
619
620 if (s->histogram_boundaries[mid - 1] > duration)
621 hi = mid;
622 else
623 lo = mid;
624 }
625 p->histogram[lo]++;
626 }
627 }
628
629#if BITS_PER_LONG == 32
630 local_irq_restore(flags);
631#else
632 preempt_enable();
633#endif
634}
635
636static void __dm_stat_bio(struct dm_stat *s, int bi_rw,
637 sector_t bi_sector, sector_t end_sector,
638 bool end, unsigned long duration_jiffies,
639 struct dm_stats_aux *stats_aux)
640{
641 sector_t rel_sector, offset, todo, fragment_len;
642 size_t entry;
643
644 if (end_sector <= s->start || bi_sector >= s->end)
645 return;
646 if (unlikely(bi_sector < s->start)) {
647 rel_sector = 0;
648 todo = end_sector - s->start;
649 } else {
650 rel_sector = bi_sector - s->start;
651 todo = end_sector - bi_sector;
652 }
653 if (unlikely(end_sector > s->end))
654 todo -= (end_sector - s->end);
655
656 offset = dm_sector_div64(rel_sector, s->step);
657 entry = rel_sector;
658 do {
659 if (WARN_ON_ONCE(entry >= s->n_entries)) {
660 DMCRIT("Invalid area access in region id %d", s->id);
661 return;
662 }
663 fragment_len = todo;
664 if (fragment_len > s->step - offset)
665 fragment_len = s->step - offset;
666 dm_stat_for_entry(s, entry, bi_rw, fragment_len,
667 stats_aux, end, duration_jiffies);
668 todo -= fragment_len;
669 entry++;
670 offset = 0;
671 } while (unlikely(todo != 0));
672}
673
674void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
675 sector_t bi_sector, unsigned int bi_sectors, bool end,
676 unsigned long start_time,
677 struct dm_stats_aux *stats_aux)
678{
679 struct dm_stat *s;
680 sector_t end_sector;
681 struct dm_stats_last_position *last;
682 bool got_precise_time;
683 unsigned long duration_jiffies = 0;
684
685 if (unlikely(!bi_sectors))
686 return;
687
688 end_sector = bi_sector + bi_sectors;
689
690 if (!end) {
691 /*
692 * A race condition can at worst result in the merged flag being
693 * misrepresented, so we don't have to disable preemption here.
694 */
695 last = raw_cpu_ptr(stats->last);
696 stats_aux->merged =
697 bi_sector == READ_ONCE(last->last_sector) &&
698 (bi_rw == WRITE) == (READ_ONCE(last->last_rw) == WRITE);
699 WRITE_ONCE(last->last_sector, end_sector);
700 WRITE_ONCE(last->last_rw, bi_rw);
701 } else
702 duration_jiffies = jiffies - start_time;
703
704 rcu_read_lock();
705
706 got_precise_time = false;
707 list_for_each_entry_rcu(s, &stats->list, list_entry) {
708 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {
709 /* start (!end) duration_ns is set by DM core's alloc_io() */
710 if (end)
711 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;
712 got_precise_time = true;
713 }
714 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
715 }
716
717 rcu_read_unlock();
718}
719
720static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
721 struct dm_stat *s, size_t x)
722{
723 int cpu;
724 struct dm_stat_percpu *p;
725
726 local_irq_disable();
727 p = &s->stat_percpu[smp_processor_id()][x];
728 dm_stat_round(s, shared, p);
729 local_irq_enable();
730
731 shared->tmp.sectors[READ] = 0;
732 shared->tmp.sectors[WRITE] = 0;
733 shared->tmp.ios[READ] = 0;
734 shared->tmp.ios[WRITE] = 0;
735 shared->tmp.merges[READ] = 0;
736 shared->tmp.merges[WRITE] = 0;
737 shared->tmp.ticks[READ] = 0;
738 shared->tmp.ticks[WRITE] = 0;
739 shared->tmp.io_ticks[READ] = 0;
740 shared->tmp.io_ticks[WRITE] = 0;
741 shared->tmp.io_ticks_total = 0;
742 shared->tmp.time_in_queue = 0;
743
744 if (s->n_histogram_entries)
745 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
746
747 for_each_possible_cpu(cpu) {
748 p = &s->stat_percpu[cpu][x];
749 shared->tmp.sectors[READ] += READ_ONCE(p->sectors[READ]);
750 shared->tmp.sectors[WRITE] += READ_ONCE(p->sectors[WRITE]);
751 shared->tmp.ios[READ] += READ_ONCE(p->ios[READ]);
752 shared->tmp.ios[WRITE] += READ_ONCE(p->ios[WRITE]);
753 shared->tmp.merges[READ] += READ_ONCE(p->merges[READ]);
754 shared->tmp.merges[WRITE] += READ_ONCE(p->merges[WRITE]);
755 shared->tmp.ticks[READ] += READ_ONCE(p->ticks[READ]);
756 shared->tmp.ticks[WRITE] += READ_ONCE(p->ticks[WRITE]);
757 shared->tmp.io_ticks[READ] += READ_ONCE(p->io_ticks[READ]);
758 shared->tmp.io_ticks[WRITE] += READ_ONCE(p->io_ticks[WRITE]);
759 shared->tmp.io_ticks_total += READ_ONCE(p->io_ticks_total);
760 shared->tmp.time_in_queue += READ_ONCE(p->time_in_queue);
761 if (s->n_histogram_entries) {
762 unsigned int i;
763
764 for (i = 0; i < s->n_histogram_entries + 1; i++)
765 shared->tmp.histogram[i] += READ_ONCE(p->histogram[i]);
766 }
767 }
768}
769
770static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
771 bool init_tmp_percpu_totals)
772{
773 size_t x;
774 struct dm_stat_shared *shared;
775 struct dm_stat_percpu *p;
776
777 for (x = idx_start; x < idx_end; x++) {
778 shared = &s->stat_shared[x];
779 if (init_tmp_percpu_totals)
780 __dm_stat_init_temporary_percpu_totals(shared, s, x);
781 local_irq_disable();
782 p = &s->stat_percpu[smp_processor_id()][x];
783 p->sectors[READ] -= shared->tmp.sectors[READ];
784 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
785 p->ios[READ] -= shared->tmp.ios[READ];
786 p->ios[WRITE] -= shared->tmp.ios[WRITE];
787 p->merges[READ] -= shared->tmp.merges[READ];
788 p->merges[WRITE] -= shared->tmp.merges[WRITE];
789 p->ticks[READ] -= shared->tmp.ticks[READ];
790 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
791 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
792 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
793 p->io_ticks_total -= shared->tmp.io_ticks_total;
794 p->time_in_queue -= shared->tmp.time_in_queue;
795 local_irq_enable();
796 if (s->n_histogram_entries) {
797 unsigned int i;
798
799 for (i = 0; i < s->n_histogram_entries + 1; i++) {
800 local_irq_disable();
801 p = &s->stat_percpu[smp_processor_id()][x];
802 p->histogram[i] -= shared->tmp.histogram[i];
803 local_irq_enable();
804 }
805 }
806 cond_resched();
807 }
808}
809
810static int dm_stats_clear(struct dm_stats *stats, int id)
811{
812 struct dm_stat *s;
813
814 mutex_lock(&stats->mutex);
815
816 s = __dm_stats_find(stats, id);
817 if (!s) {
818 mutex_unlock(&stats->mutex);
819 return -ENOENT;
820 }
821
822 __dm_stat_clear(s, 0, s->n_entries, true);
823
824 mutex_unlock(&stats->mutex);
825
826 return 1;
827}
828
829/*
830 * This is like jiffies_to_msec, but works for 64-bit values.
831 */
832static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
833{
834 unsigned long long result;
835 unsigned int mult;
836
837 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
838 return j;
839
840 result = 0;
841 if (j)
842 result = jiffies_to_msecs(j & 0x3fffff);
843 if (j >= 1 << 22) {
844 mult = jiffies_to_msecs(1 << 22);
845 result += (unsigned long long)mult * ((j >> 22) & 0x3fffff);
846 }
847 if (j >= 1ULL << 44)
848 result += (unsigned long long)mult * (unsigned long long)(1 << 22) * (j >> 44);
849
850 return result;
851}
852
853static int dm_stats_print(struct dm_stats *stats, int id,
854 size_t idx_start, size_t idx_len,
855 bool clear, char *result, unsigned int maxlen)
856{
857 unsigned int sz = 0;
858 struct dm_stat *s;
859 size_t x;
860 sector_t start, end, step;
861 size_t idx_end;
862 struct dm_stat_shared *shared;
863
864 /*
865 * Output format:
866 * <start_sector>+<length> counters
867 */
868
869 mutex_lock(&stats->mutex);
870
871 s = __dm_stats_find(stats, id);
872 if (!s) {
873 mutex_unlock(&stats->mutex);
874 return -ENOENT;
875 }
876
877 idx_end = idx_start + idx_len;
878 if (idx_end < idx_start ||
879 idx_end > s->n_entries)
880 idx_end = s->n_entries;
881
882 if (idx_start > idx_end)
883 idx_start = idx_end;
884
885 step = s->step;
886 start = s->start + (step * idx_start);
887
888 for (x = idx_start; x < idx_end; x++, start = end) {
889 shared = &s->stat_shared[x];
890 end = start + step;
891 if (unlikely(end > s->end))
892 end = s->end;
893
894 __dm_stat_init_temporary_percpu_totals(shared, s, x);
895
896 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",
897 (unsigned long long)start,
898 (unsigned long long)step,
899 shared->tmp.ios[READ],
900 shared->tmp.merges[READ],
901 shared->tmp.sectors[READ],
902 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),
903 shared->tmp.ios[WRITE],
904 shared->tmp.merges[WRITE],
905 shared->tmp.sectors[WRITE],
906 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),
907 dm_stat_in_flight(shared),
908 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),
909 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),
910 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),
911 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));
912 if (s->n_histogram_entries) {
913 unsigned int i;
914
915 for (i = 0; i < s->n_histogram_entries + 1; i++)
916 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
917 }
918 DMEMIT("\n");
919
920 if (unlikely(sz + 1 >= maxlen))
921 goto buffer_overflow;
922
923 cond_resched();
924 }
925
926 if (clear)
927 __dm_stat_clear(s, idx_start, idx_end, false);
928
929buffer_overflow:
930 mutex_unlock(&stats->mutex);
931
932 return 1;
933}
934
935static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
936{
937 struct dm_stat *s;
938 const char *new_aux_data;
939
940 mutex_lock(&stats->mutex);
941
942 s = __dm_stats_find(stats, id);
943 if (!s) {
944 mutex_unlock(&stats->mutex);
945 return -ENOENT;
946 }
947
948 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
949 if (!new_aux_data) {
950 mutex_unlock(&stats->mutex);
951 return -ENOMEM;
952 }
953
954 kfree(s->aux_data);
955 s->aux_data = new_aux_data;
956
957 mutex_unlock(&stats->mutex);
958
959 return 0;
960}
961
962static int parse_histogram(const char *h, unsigned int *n_histogram_entries,
963 unsigned long long **histogram_boundaries)
964{
965 const char *q;
966 unsigned int n;
967 unsigned long long last;
968
969 *n_histogram_entries = 1;
970 for (q = h; *q; q++)
971 if (*q == ',')
972 (*n_histogram_entries)++;
973
974 *histogram_boundaries = kmalloc_objs(unsigned long long,
975 *n_histogram_entries);
976 if (!*histogram_boundaries)
977 return -ENOMEM;
978
979 n = 0;
980 last = 0;
981 while (1) {
982 unsigned long long hi;
983 int s;
984 char ch;
985
986 s = sscanf(h, "%llu%c", &hi, &ch);
987 if (!s || (s == 2 && ch != ','))
988 return -EINVAL;
989 if (hi <= last)
990 return -EINVAL;
991 last = hi;
992 (*histogram_boundaries)[n] = hi;
993 if (s == 1)
994 return 0;
995 h = strchr(h, ',') + 1;
996 n++;
997 }
998}
999
1000static int message_stats_create(struct mapped_device *md,
1001 unsigned int argc, char **argv,
1002 char *result, unsigned int maxlen)
1003{
1004 int r;
1005 int id;
1006 char dummy;
1007 unsigned long long start, end, len, step;
1008 unsigned int divisor;
1009 const char *program_id, *aux_data;
1010 unsigned int stat_flags = 0;
1011 unsigned int n_histogram_entries = 0;
1012 unsigned long long *histogram_boundaries = NULL;
1013 struct dm_arg_set as, as_backup;
1014 const char *a;
1015 unsigned int feature_args;
1016
1017 /*
1018 * Input format:
1019 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
1020 */
1021
1022 if (argc < 3)
1023 goto ret_einval;
1024
1025 as.argc = argc;
1026 as.argv = argv;
1027 dm_consume_args(&as, 1);
1028
1029 a = dm_shift_arg(&as);
1030 if (!strcmp(a, "-")) {
1031 start = 0;
1032 len = dm_get_size(md);
1033 if (!len)
1034 len = 1;
1035 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
1036 start != (sector_t)start || len != (sector_t)len)
1037 goto ret_einval;
1038
1039 end = start + len;
1040 if (start >= end)
1041 goto ret_einval;
1042
1043 a = dm_shift_arg(&as);
1044 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
1045 if (!divisor)
1046 return -EINVAL;
1047 step = end - start;
1048 if (do_div(step, divisor))
1049 step++;
1050 if (!step)
1051 step = 1;
1052 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
1053 step != (sector_t)step || !step)
1054 goto ret_einval;
1055
1056 as_backup = as;
1057 a = dm_shift_arg(&as);
1058 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
1059 while (feature_args--) {
1060 a = dm_shift_arg(&as);
1061 if (!a)
1062 goto ret_einval;
1063 if (!strcasecmp(a, "precise_timestamps"))
1064 stat_flags |= STAT_PRECISE_TIMESTAMPS;
1065 else if (!strncasecmp(a, "histogram:", 10)) {
1066 if (n_histogram_entries)
1067 goto ret_einval;
1068 r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries);
1069 if (r)
1070 goto ret;
1071 } else
1072 goto ret_einval;
1073 }
1074 } else {
1075 as = as_backup;
1076 }
1077
1078 program_id = "-";
1079 aux_data = "-";
1080
1081 a = dm_shift_arg(&as);
1082 if (a)
1083 program_id = a;
1084
1085 a = dm_shift_arg(&as);
1086 if (a)
1087 aux_data = a;
1088
1089 if (as.argc)
1090 goto ret_einval;
1091
1092 /*
1093 * If a buffer overflow happens after we created the region,
1094 * it's too late (the userspace would retry with a larger
1095 * buffer, but the region id that caused the overflow is already
1096 * leaked). So we must detect buffer overflow in advance.
1097 */
1098 snprintf(result, maxlen, "%d", INT_MAX);
1099 if (dm_message_test_buffer_overflow(result, maxlen)) {
1100 r = 1;
1101 goto ret;
1102 }
1103
1104 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags,
1105 n_histogram_entries, histogram_boundaries, program_id, aux_data,
1106 dm_internal_suspend_fast, dm_internal_resume_fast, md);
1107 if (id < 0) {
1108 r = id;
1109 goto ret;
1110 }
1111
1112 snprintf(result, maxlen, "%d", id);
1113
1114 r = 1;
1115 goto ret;
1116
1117ret_einval:
1118 r = -EINVAL;
1119ret:
1120 kfree(histogram_boundaries);
1121 return r;
1122}
1123
1124static int message_stats_delete(struct mapped_device *md,
1125 unsigned int argc, char **argv)
1126{
1127 int id;
1128 char dummy;
1129
1130 if (argc != 2)
1131 return -EINVAL;
1132
1133 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1134 return -EINVAL;
1135
1136 return dm_stats_delete(dm_get_stats(md), id);
1137}
1138
1139static int message_stats_clear(struct mapped_device *md,
1140 unsigned int argc, char **argv)
1141{
1142 int id;
1143 char dummy;
1144
1145 if (argc != 2)
1146 return -EINVAL;
1147
1148 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1149 return -EINVAL;
1150
1151 return dm_stats_clear(dm_get_stats(md), id);
1152}
1153
1154static int message_stats_list(struct mapped_device *md,
1155 unsigned int argc, char **argv,
1156 char *result, unsigned int maxlen)
1157{
1158 int r;
1159 const char *program = NULL;
1160
1161 if (argc < 1 || argc > 2)
1162 return -EINVAL;
1163
1164 if (argc > 1) {
1165 program = kstrdup(argv[1], GFP_KERNEL);
1166 if (!program)
1167 return -ENOMEM;
1168 }
1169
1170 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
1171
1172 kfree(program);
1173
1174 return r;
1175}
1176
1177static int message_stats_print(struct mapped_device *md,
1178 unsigned int argc, char **argv, bool clear,
1179 char *result, unsigned int maxlen)
1180{
1181 int id;
1182 char dummy;
1183 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1184
1185 if (argc != 2 && argc != 4)
1186 return -EINVAL;
1187
1188 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1189 return -EINVAL;
1190
1191 if (argc > 3) {
1192 if (strcmp(argv[2], "-") &&
1193 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1194 return -EINVAL;
1195 if (strcmp(argv[3], "-") &&
1196 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1197 return -EINVAL;
1198 }
1199
1200 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
1201 result, maxlen);
1202}
1203
1204static int message_stats_set_aux(struct mapped_device *md,
1205 unsigned int argc, char **argv)
1206{
1207 int id;
1208 char dummy;
1209
1210 if (argc != 3)
1211 return -EINVAL;
1212
1213 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1214 return -EINVAL;
1215
1216 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
1217}
1218
1219int dm_stats_message(struct mapped_device *md, unsigned int argc, char **argv,
1220 char *result, unsigned int maxlen)
1221{
1222 int r;
1223
1224 /* All messages here must start with '@' */
1225 if (!strcasecmp(argv[0], "@stats_create"))
1226 r = message_stats_create(md, argc, argv, result, maxlen);
1227 else if (!strcasecmp(argv[0], "@stats_delete"))
1228 r = message_stats_delete(md, argc, argv);
1229 else if (!strcasecmp(argv[0], "@stats_clear"))
1230 r = message_stats_clear(md, argc, argv);
1231 else if (!strcasecmp(argv[0], "@stats_list"))
1232 r = message_stats_list(md, argc, argv, result, maxlen);
1233 else if (!strcasecmp(argv[0], "@stats_print"))
1234 r = message_stats_print(md, argc, argv, false, result, maxlen);
1235 else if (!strcasecmp(argv[0], "@stats_print_clear"))
1236 r = message_stats_print(md, argc, argv, true, result, maxlen);
1237 else if (!strcasecmp(argv[0], "@stats_set_aux"))
1238 r = message_stats_set_aux(md, argc, argv);
1239 else
1240 return 2; /* this wasn't a stats message */
1241
1242 if (r == -EINVAL)
1243 DMCRIT("Invalid parameters for message %s", argv[0]);
1244
1245 return r;
1246}
1247
1248int __init dm_statistics_init(void)
1249{
1250 shared_memory_amount = 0;
1251 dm_stat_need_rcu_barrier = 0;
1252 return 0;
1253}
1254
1255void dm_statistics_exit(void)
1256{
1257 if (dm_stat_need_rcu_barrier)
1258 rcu_barrier();
1259 if (WARN_ON(shared_memory_amount))
1260 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
1261}
1262
1263module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, 0444);
1264MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");