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(lock: &shared_memory_lock);
105
106 ret = __check_shared_memory(alloc_size);
107
108 spin_unlock_irq(lock: &shared_memory_lock);
109
110 return ret;
111}
112
113static bool claim_shared_memory(size_t alloc_size)
114{
115 spin_lock_irq(lock: &shared_memory_lock);
116
117 if (!__check_shared_memory(alloc_size)) {
118 spin_unlock_irq(lock: &shared_memory_lock);
119 return false;
120 }
121
122 shared_memory_amount += alloc_size;
123
124 spin_unlock_irq(lock: &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(lock: &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(lock: &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(addr: 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(objp: s->histogram_boundaries);
178 kfree(objp: s->program_id);
179 kfree(objp: s->aux_data);
180 for_each_possible_cpu(cpu) {
181 dm_kvfree(ptr: s->stat_percpu[cpu][0].histogram, alloc_size: s->histogram_alloc_size);
182 dm_kvfree(ptr: s->stat_percpu[cpu], alloc_size: s->percpu_alloc_size);
183 }
184 dm_kvfree(ptr: s->stat_shared[0].tmp.histogram, alloc_size: s->histogram_alloc_size);
185 dm_kvfree(ptr: s, alloc_size: s->shared_alloc_size);
186}
187
188static int dm_stat_in_flight(struct dm_stat_shared *shared)
189{
190 return atomic_read(v: &shared->in_flight[READ]) +
191 atomic_read(v: &shared->in_flight[WRITE]);
192}
193
194int dm_stats_init(struct dm_stats *stats)
195{
196 int cpu;
197 struct dm_stats_last_position *last;
198
199 mutex_init(&stats->mutex);
200 INIT_LIST_HEAD(list: &stats->list);
201 stats->precise_timestamps = false;
202 stats->last = alloc_percpu(struct dm_stats_last_position);
203 if (!stats->last)
204 return -ENOMEM;
205
206 for_each_possible_cpu(cpu) {
207 last = per_cpu_ptr(stats->last, cpu);
208 last->last_sector = (sector_t)ULLONG_MAX;
209 last->last_rw = UINT_MAX;
210 }
211
212 return 0;
213}
214
215void dm_stats_cleanup(struct dm_stats *stats)
216{
217 size_t ni;
218 struct dm_stat *s;
219 struct dm_stat_shared *shared;
220
221 while (!list_empty(head: &stats->list)) {
222 s = container_of(stats->list.next, struct dm_stat, list_entry);
223 list_del(entry: &s->list_entry);
224 for (ni = 0; ni < s->n_entries; ni++) {
225 shared = &s->stat_shared[ni];
226 if (WARN_ON(dm_stat_in_flight(shared))) {
227 DMCRIT("leaked in-flight counter at index %lu "
228 "(start %llu, end %llu, step %llu): reads %d, writes %d",
229 (unsigned long)ni,
230 (unsigned long long)s->start,
231 (unsigned long long)s->end,
232 (unsigned long long)s->step,
233 atomic_read(&shared->in_flight[READ]),
234 atomic_read(&shared->in_flight[WRITE]));
235 }
236 cond_resched();
237 }
238 dm_stat_free(head: &s->rcu_head);
239 }
240 free_percpu(pdata: stats->last);
241 mutex_destroy(lock: &stats->mutex);
242}
243
244static void dm_stats_recalc_precise_timestamps(struct dm_stats *stats)
245{
246 struct list_head *l;
247 struct dm_stat *tmp_s;
248 bool precise_timestamps = false;
249
250 list_for_each(l, &stats->list) {
251 tmp_s = container_of(l, struct dm_stat, list_entry);
252 if (tmp_s->stat_flags & STAT_PRECISE_TIMESTAMPS) {
253 precise_timestamps = true;
254 break;
255 }
256 }
257 stats->precise_timestamps = precise_timestamps;
258}
259
260static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
261 sector_t step, unsigned int stat_flags,
262 unsigned int n_histogram_entries,
263 unsigned long long *histogram_boundaries,
264 const char *program_id, const char *aux_data,
265 void (*suspend_callback)(struct mapped_device *),
266 void (*resume_callback)(struct mapped_device *),
267 struct mapped_device *md)
268{
269 struct list_head *l;
270 struct dm_stat *s, *tmp_s;
271 sector_t n_entries;
272 size_t ni;
273 size_t shared_alloc_size;
274 size_t percpu_alloc_size;
275 size_t histogram_alloc_size;
276 struct dm_stat_percpu *p;
277 int cpu;
278 int ret_id;
279 int r;
280
281 if (end < start || !step)
282 return -EINVAL;
283
284 n_entries = end - start;
285 if (dm_sector_div64(n_entries, step))
286 n_entries++;
287
288 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
289 return -EOVERFLOW;
290
291 if (n_entries > DM_STAT_MAX_ENTRIES)
292 return -EOVERFLOW;
293
294 shared_alloc_size = struct_size(s, stat_shared, n_entries);
295 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
296 return -EOVERFLOW;
297
298 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
299 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
300 return -EOVERFLOW;
301
302 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
303 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
304 return -EOVERFLOW;
305
306 if ((n_histogram_entries + 1) * (size_t)n_entries > DM_STAT_MAX_HISTOGRAM_ENTRIES)
307 return -EOVERFLOW;
308
309 if (!check_shared_memory(alloc_size: shared_alloc_size + histogram_alloc_size +
310 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
311 return -ENOMEM;
312
313 s = dm_kvzalloc(alloc_size: shared_alloc_size, NUMA_NO_NODE);
314 if (!s)
315 return -ENOMEM;
316
317 s->stat_flags = stat_flags;
318 s->n_entries = n_entries;
319 s->start = start;
320 s->end = end;
321 s->step = step;
322 s->shared_alloc_size = shared_alloc_size;
323 s->percpu_alloc_size = percpu_alloc_size;
324 s->histogram_alloc_size = histogram_alloc_size;
325
326 s->n_histogram_entries = n_histogram_entries;
327 s->histogram_boundaries = kmemdup(histogram_boundaries,
328 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
329 if (!s->histogram_boundaries) {
330 r = -ENOMEM;
331 goto out;
332 }
333
334 s->program_id = kstrdup(s: program_id, GFP_KERNEL);
335 if (!s->program_id) {
336 r = -ENOMEM;
337 goto out;
338 }
339 s->aux_data = kstrdup(s: aux_data, GFP_KERNEL);
340 if (!s->aux_data) {
341 r = -ENOMEM;
342 goto out;
343 }
344
345 for (ni = 0; ni < n_entries; ni++) {
346 atomic_set(v: &s->stat_shared[ni].in_flight[READ], i: 0);
347 atomic_set(v: &s->stat_shared[ni].in_flight[WRITE], i: 0);
348 cond_resched();
349 }
350
351 if (s->n_histogram_entries) {
352 unsigned long long *hi;
353
354 hi = dm_kvzalloc(alloc_size: s->histogram_alloc_size, NUMA_NO_NODE);
355 if (!hi) {
356 r = -ENOMEM;
357 goto out;
358 }
359 for (ni = 0; ni < n_entries; ni++) {
360 s->stat_shared[ni].tmp.histogram = hi;
361 hi += s->n_histogram_entries + 1;
362 cond_resched();
363 }
364 }
365
366 for_each_possible_cpu(cpu) {
367 p = dm_kvzalloc(alloc_size: percpu_alloc_size, cpu_to_node(cpu));
368 if (!p) {
369 r = -ENOMEM;
370 goto out;
371 }
372 s->stat_percpu[cpu] = p;
373 if (s->n_histogram_entries) {
374 unsigned long long *hi;
375
376 hi = dm_kvzalloc(alloc_size: s->histogram_alloc_size, cpu_to_node(cpu));
377 if (!hi) {
378 r = -ENOMEM;
379 goto out;
380 }
381 for (ni = 0; ni < n_entries; ni++) {
382 p[ni].histogram = hi;
383 hi += s->n_histogram_entries + 1;
384 cond_resched();
385 }
386 }
387 }
388
389 /*
390 * Suspend/resume to make sure there is no i/o in flight,
391 * so that newly created statistics will be exact.
392 *
393 * (note: we couldn't suspend earlier because we must not
394 * allocate memory while suspended)
395 */
396 suspend_callback(md);
397
398 mutex_lock(&stats->mutex);
399 s->id = 0;
400 list_for_each(l, &stats->list) {
401 tmp_s = container_of(l, struct dm_stat, list_entry);
402 if (WARN_ON(tmp_s->id < s->id)) {
403 r = -EINVAL;
404 goto out_unlock_resume;
405 }
406 if (tmp_s->id > s->id)
407 break;
408 if (unlikely(s->id == INT_MAX)) {
409 r = -ENFILE;
410 goto out_unlock_resume;
411 }
412 s->id++;
413 }
414 ret_id = s->id;
415 list_add_tail_rcu(new: &s->list_entry, head: l);
416
417 dm_stats_recalc_precise_timestamps(stats);
418
419 if (!static_key_enabled(&stats_enabled.key))
420 static_branch_enable(&stats_enabled);
421
422 mutex_unlock(lock: &stats->mutex);
423
424 resume_callback(md);
425
426 return ret_id;
427
428out_unlock_resume:
429 mutex_unlock(lock: &stats->mutex);
430 resume_callback(md);
431out:
432 dm_stat_free(head: &s->rcu_head);
433 return r;
434}
435
436static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
437{
438 struct dm_stat *s;
439
440 list_for_each_entry(s, &stats->list, list_entry) {
441 if (s->id > id)
442 break;
443 if (s->id == id)
444 return s;
445 }
446
447 return NULL;
448}
449
450static int dm_stats_delete(struct dm_stats *stats, int id)
451{
452 struct dm_stat *s;
453 int cpu;
454
455 mutex_lock(&stats->mutex);
456
457 s = __dm_stats_find(stats, id);
458 if (!s) {
459 mutex_unlock(lock: &stats->mutex);
460 return -ENOENT;
461 }
462
463 list_del_rcu(entry: &s->list_entry);
464
465 dm_stats_recalc_precise_timestamps(stats);
466
467 mutex_unlock(lock: &stats->mutex);
468
469 /*
470 * vfree can't be called from RCU callback
471 */
472 for_each_possible_cpu(cpu)
473 if (is_vmalloc_addr(x: s->stat_percpu) ||
474 is_vmalloc_addr(x: s->stat_percpu[cpu][0].histogram))
475 goto do_sync_free;
476 if (is_vmalloc_addr(x: s) ||
477 is_vmalloc_addr(x: s->stat_shared[0].tmp.histogram)) {
478do_sync_free:
479 synchronize_rcu_expedited();
480 dm_stat_free(head: &s->rcu_head);
481 } else {
482 WRITE_ONCE(dm_stat_need_rcu_barrier, 1);
483 call_rcu(head: &s->rcu_head, func: dm_stat_free);
484 }
485 return 0;
486}
487
488static int dm_stats_list(struct dm_stats *stats, const char *program,
489 char *result, unsigned int maxlen)
490{
491 struct dm_stat *s;
492 sector_t len;
493 unsigned int sz = 0;
494
495 /*
496 * Output format:
497 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
498 */
499
500 mutex_lock(&stats->mutex);
501 list_for_each_entry(s, &stats->list, list_entry) {
502 if (!program || !strcmp(program, s->program_id)) {
503 len = s->end - s->start;
504 DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
505 (unsigned long long)s->start,
506 (unsigned long long)len,
507 (unsigned long long)s->step,
508 s->program_id,
509 s->aux_data);
510 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
511 DMEMIT(" precise_timestamps");
512 if (s->n_histogram_entries) {
513 unsigned int i;
514
515 DMEMIT(" histogram:");
516 for (i = 0; i < s->n_histogram_entries; i++) {
517 if (i)
518 DMEMIT(",");
519 DMEMIT("%llu", s->histogram_boundaries[i]);
520 }
521 }
522 DMEMIT("\n");
523 }
524 cond_resched();
525 }
526 mutex_unlock(lock: &stats->mutex);
527
528 return 1;
529}
530
531static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
532 struct dm_stat_percpu *p)
533{
534 /*
535 * This is racy, but so is part_round_stats_single.
536 */
537 unsigned long long now, difference;
538 unsigned int in_flight_read, in_flight_write;
539
540 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
541 now = jiffies;
542 else
543 now = ktime_to_ns(kt: ktime_get());
544
545 difference = now - shared->stamp;
546 if (!difference)
547 return;
548
549 in_flight_read = (unsigned int)atomic_read(v: &shared->in_flight[READ]);
550 in_flight_write = (unsigned int)atomic_read(v: &shared->in_flight[WRITE]);
551 if (in_flight_read)
552 p->io_ticks[READ] += difference;
553 if (in_flight_write)
554 p->io_ticks[WRITE] += difference;
555 if (in_flight_read + in_flight_write) {
556 p->io_ticks_total += difference;
557 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
558 }
559 shared->stamp = now;
560}
561
562static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
563 int idx, sector_t len,
564 struct dm_stats_aux *stats_aux, bool end,
565 unsigned long duration_jiffies)
566{
567 struct dm_stat_shared *shared = &s->stat_shared[entry];
568 struct dm_stat_percpu *p;
569
570 /*
571 * For strict correctness we should use local_irq_save/restore
572 * instead of preempt_disable/enable.
573 *
574 * preempt_disable/enable is racy if the driver finishes bios
575 * from non-interrupt context as well as from interrupt context
576 * or from more different interrupts.
577 *
578 * On 64-bit architectures the race only results in not counting some
579 * events, so it is acceptable. On 32-bit architectures the race could
580 * cause the counter going off by 2^32, so we need to do proper locking
581 * there.
582 *
583 * part_stat_lock()/part_stat_unlock() have this race too.
584 */
585#if BITS_PER_LONG == 32
586 unsigned long flags;
587
588 local_irq_save(flags);
589#else
590 preempt_disable();
591#endif
592 p = &s->stat_percpu[smp_processor_id()][entry];
593
594 if (!end) {
595 dm_stat_round(s, shared, p);
596 atomic_inc(v: &shared->in_flight[idx]);
597 } else {
598 unsigned long long duration;
599
600 dm_stat_round(s, shared, p);
601 atomic_dec(v: &shared->in_flight[idx]);
602 p->sectors[idx] += len;
603 p->ios[idx] += 1;
604 p->merges[idx] += stats_aux->merged;
605 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
606 p->ticks[idx] += duration_jiffies;
607 duration = jiffies_to_msecs(j: duration_jiffies);
608 } else {
609 p->ticks[idx] += stats_aux->duration_ns;
610 duration = stats_aux->duration_ns;
611 }
612 if (s->n_histogram_entries) {
613 unsigned int lo = 0, hi = s->n_histogram_entries + 1;
614
615 while (lo + 1 < hi) {
616 unsigned int mid = (lo + hi) / 2;
617
618 if (s->histogram_boundaries[mid - 1] > duration)
619 hi = mid;
620 else
621 lo = mid;
622 }
623 p->histogram[lo]++;
624 }
625 }
626
627#if BITS_PER_LONG == 32
628 local_irq_restore(flags);
629#else
630 preempt_enable();
631#endif
632}
633
634static void __dm_stat_bio(struct dm_stat *s, int bi_rw,
635 sector_t bi_sector, sector_t end_sector,
636 bool end, unsigned long duration_jiffies,
637 struct dm_stats_aux *stats_aux)
638{
639 sector_t rel_sector, offset, todo, fragment_len;
640 size_t entry;
641
642 if (end_sector <= s->start || bi_sector >= s->end)
643 return;
644 if (unlikely(bi_sector < s->start)) {
645 rel_sector = 0;
646 todo = end_sector - s->start;
647 } else {
648 rel_sector = bi_sector - s->start;
649 todo = end_sector - bi_sector;
650 }
651 if (unlikely(end_sector > s->end))
652 todo -= (end_sector - s->end);
653
654 offset = dm_sector_div64(rel_sector, s->step);
655 entry = rel_sector;
656 do {
657 if (WARN_ON_ONCE(entry >= s->n_entries)) {
658 DMCRIT("Invalid area access in region id %d", s->id);
659 return;
660 }
661 fragment_len = todo;
662 if (fragment_len > s->step - offset)
663 fragment_len = s->step - offset;
664 dm_stat_for_entry(s, entry, idx: bi_rw, len: fragment_len,
665 stats_aux, end, duration_jiffies);
666 todo -= fragment_len;
667 entry++;
668 offset = 0;
669 } while (unlikely(todo != 0));
670}
671
672void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
673 sector_t bi_sector, unsigned int bi_sectors, bool end,
674 unsigned long start_time,
675 struct dm_stats_aux *stats_aux)
676{
677 struct dm_stat *s;
678 sector_t end_sector;
679 struct dm_stats_last_position *last;
680 bool got_precise_time;
681 unsigned long duration_jiffies = 0;
682
683 if (unlikely(!bi_sectors))
684 return;
685
686 end_sector = bi_sector + bi_sectors;
687
688 if (!end) {
689 /*
690 * A race condition can at worst result in the merged flag being
691 * misrepresented, so we don't have to disable preemption here.
692 */
693 last = raw_cpu_ptr(stats->last);
694 stats_aux->merged =
695 (bi_sector == (READ_ONCE(last->last_sector) &&
696 ((bi_rw == WRITE) ==
697 (READ_ONCE(last->last_rw) == WRITE))
698 ));
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(kt: 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(lock: &stats->mutex);
819 return -ENOENT;
820 }
821
822 __dm_stat_clear(s, idx_start: 0, idx_end: s->n_entries, init_tmp_percpu_totals: true);
823
824 mutex_unlock(lock: &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: j & 0x3fffff);
843 if (j >= 1 << 22) {
844 mult = jiffies_to_msecs(j: 1 << 22);
845 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j: (j >> 22) & 0x3fffff);
846 }
847 if (j >= 1ULL << 44)
848 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j: 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(lock: &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, init_tmp_percpu_totals: false);
928
929buffer_overflow:
930 mutex_unlock(lock: &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(lock: &stats->mutex);
945 return -ENOENT;
946 }
947
948 new_aux_data = kstrdup(s: aux_data, GFP_KERNEL);
949 if (!new_aux_data) {
950 mutex_unlock(lock: &stats->mutex);
951 return -ENOMEM;
952 }
953
954 kfree(objp: s->aux_data);
955 s->aux_data = new_aux_data;
956
957 mutex_unlock(lock: &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_array(*n_histogram_entries,
975 sizeof(unsigned long long),
976 GFP_KERNEL);
977 if (!*histogram_boundaries)
978 return -ENOMEM;
979
980 n = 0;
981 last = 0;
982 while (1) {
983 unsigned long long hi;
984 int s;
985 char ch;
986
987 s = sscanf(h, "%llu%c", &hi, &ch);
988 if (!s || (s == 2 && ch != ','))
989 return -EINVAL;
990 if (hi <= last)
991 return -EINVAL;
992 last = hi;
993 (*histogram_boundaries)[n] = hi;
994 if (s == 1)
995 return 0;
996 h = strchr(h, ',') + 1;
997 n++;
998 }
999}
1000
1001static int message_stats_create(struct mapped_device *md,
1002 unsigned int argc, char **argv,
1003 char *result, unsigned int maxlen)
1004{
1005 int r;
1006 int id;
1007 char dummy;
1008 unsigned long long start, end, len, step;
1009 unsigned int divisor;
1010 const char *program_id, *aux_data;
1011 unsigned int stat_flags = 0;
1012 unsigned int n_histogram_entries = 0;
1013 unsigned long long *histogram_boundaries = NULL;
1014 struct dm_arg_set as, as_backup;
1015 const char *a;
1016 unsigned int feature_args;
1017
1018 /*
1019 * Input format:
1020 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
1021 */
1022
1023 if (argc < 3)
1024 goto ret_einval;
1025
1026 as.argc = argc;
1027 as.argv = argv;
1028 dm_consume_args(as: &as, num_args: 1);
1029
1030 a = dm_shift_arg(as: &as);
1031 if (!strcmp(a, "-")) {
1032 start = 0;
1033 len = dm_get_size(md);
1034 if (!len)
1035 len = 1;
1036 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
1037 start != (sector_t)start || len != (sector_t)len)
1038 goto ret_einval;
1039
1040 end = start + len;
1041 if (start >= end)
1042 goto ret_einval;
1043
1044 a = dm_shift_arg(as: &as);
1045 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
1046 if (!divisor)
1047 return -EINVAL;
1048 step = end - start;
1049 if (do_div(step, divisor))
1050 step++;
1051 if (!step)
1052 step = 1;
1053 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
1054 step != (sector_t)step || !step)
1055 goto ret_einval;
1056
1057 as_backup = as;
1058 a = dm_shift_arg(as: &as);
1059 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
1060 while (feature_args--) {
1061 a = dm_shift_arg(as: &as);
1062 if (!a)
1063 goto ret_einval;
1064 if (!strcasecmp(s1: a, s2: "precise_timestamps"))
1065 stat_flags |= STAT_PRECISE_TIMESTAMPS;
1066 else if (!strncasecmp(s1: a, s2: "histogram:", n: 10)) {
1067 if (n_histogram_entries)
1068 goto ret_einval;
1069 r = parse_histogram(h: a + 10, n_histogram_entries: &n_histogram_entries, histogram_boundaries: &histogram_boundaries);
1070 if (r)
1071 goto ret;
1072 } else
1073 goto ret_einval;
1074 }
1075 } else {
1076 as = as_backup;
1077 }
1078
1079 program_id = "-";
1080 aux_data = "-";
1081
1082 a = dm_shift_arg(as: &as);
1083 if (a)
1084 program_id = a;
1085
1086 a = dm_shift_arg(as: &as);
1087 if (a)
1088 aux_data = a;
1089
1090 if (as.argc)
1091 goto ret_einval;
1092
1093 /*
1094 * If a buffer overflow happens after we created the region,
1095 * it's too late (the userspace would retry with a larger
1096 * buffer, but the region id that caused the overflow is already
1097 * leaked). So we must detect buffer overflow in advance.
1098 */
1099 snprintf(buf: result, size: maxlen, fmt: "%d", INT_MAX);
1100 if (dm_message_test_buffer_overflow(result, maxlen)) {
1101 r = 1;
1102 goto ret;
1103 }
1104
1105 id = dm_stats_create(stats: dm_get_stats(md), start, end, step, stat_flags,
1106 n_histogram_entries, histogram_boundaries, program_id, aux_data,
1107 suspend_callback: dm_internal_suspend_fast, resume_callback: dm_internal_resume_fast, md);
1108 if (id < 0) {
1109 r = id;
1110 goto ret;
1111 }
1112
1113 snprintf(buf: result, size: maxlen, fmt: "%d", id);
1114
1115 r = 1;
1116 goto ret;
1117
1118ret_einval:
1119 r = -EINVAL;
1120ret:
1121 kfree(objp: histogram_boundaries);
1122 return r;
1123}
1124
1125static int message_stats_delete(struct mapped_device *md,
1126 unsigned int argc, char **argv)
1127{
1128 int id;
1129 char dummy;
1130
1131 if (argc != 2)
1132 return -EINVAL;
1133
1134 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1135 return -EINVAL;
1136
1137 return dm_stats_delete(stats: dm_get_stats(md), id);
1138}
1139
1140static int message_stats_clear(struct mapped_device *md,
1141 unsigned int argc, char **argv)
1142{
1143 int id;
1144 char dummy;
1145
1146 if (argc != 2)
1147 return -EINVAL;
1148
1149 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1150 return -EINVAL;
1151
1152 return dm_stats_clear(stats: dm_get_stats(md), id);
1153}
1154
1155static int message_stats_list(struct mapped_device *md,
1156 unsigned int argc, char **argv,
1157 char *result, unsigned int maxlen)
1158{
1159 int r;
1160 const char *program = NULL;
1161
1162 if (argc < 1 || argc > 2)
1163 return -EINVAL;
1164
1165 if (argc > 1) {
1166 program = kstrdup(s: argv[1], GFP_KERNEL);
1167 if (!program)
1168 return -ENOMEM;
1169 }
1170
1171 r = dm_stats_list(stats: dm_get_stats(md), program, result, maxlen);
1172
1173 kfree(objp: program);
1174
1175 return r;
1176}
1177
1178static int message_stats_print(struct mapped_device *md,
1179 unsigned int argc, char **argv, bool clear,
1180 char *result, unsigned int maxlen)
1181{
1182 int id;
1183 char dummy;
1184 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1185
1186 if (argc != 2 && argc != 4)
1187 return -EINVAL;
1188
1189 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1190 return -EINVAL;
1191
1192 if (argc > 3) {
1193 if (strcmp(argv[2], "-") &&
1194 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1195 return -EINVAL;
1196 if (strcmp(argv[3], "-") &&
1197 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1198 return -EINVAL;
1199 }
1200
1201 return dm_stats_print(stats: dm_get_stats(md), id, idx_start, idx_len, clear,
1202 result, maxlen);
1203}
1204
1205static int message_stats_set_aux(struct mapped_device *md,
1206 unsigned int argc, char **argv)
1207{
1208 int id;
1209 char dummy;
1210
1211 if (argc != 3)
1212 return -EINVAL;
1213
1214 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1215 return -EINVAL;
1216
1217 return dm_stats_set_aux(stats: dm_get_stats(md), id, aux_data: argv[2]);
1218}
1219
1220int dm_stats_message(struct mapped_device *md, unsigned int argc, char **argv,
1221 char *result, unsigned int maxlen)
1222{
1223 int r;
1224
1225 /* All messages here must start with '@' */
1226 if (!strcasecmp(s1: argv[0], s2: "@stats_create"))
1227 r = message_stats_create(md, argc, argv, result, maxlen);
1228 else if (!strcasecmp(s1: argv[0], s2: "@stats_delete"))
1229 r = message_stats_delete(md, argc, argv);
1230 else if (!strcasecmp(s1: argv[0], s2: "@stats_clear"))
1231 r = message_stats_clear(md, argc, argv);
1232 else if (!strcasecmp(s1: argv[0], s2: "@stats_list"))
1233 r = message_stats_list(md, argc, argv, result, maxlen);
1234 else if (!strcasecmp(s1: argv[0], s2: "@stats_print"))
1235 r = message_stats_print(md, argc, argv, clear: false, result, maxlen);
1236 else if (!strcasecmp(s1: argv[0], s2: "@stats_print_clear"))
1237 r = message_stats_print(md, argc, argv, clear: true, result, maxlen);
1238 else if (!strcasecmp(s1: argv[0], s2: "@stats_set_aux"))
1239 r = message_stats_set_aux(md, argc, argv);
1240 else
1241 return 2; /* this wasn't a stats message */
1242
1243 if (r == -EINVAL)
1244 DMCRIT("Invalid parameters for message %s", argv[0]);
1245
1246 return r;
1247}
1248
1249int __init dm_statistics_init(void)
1250{
1251 shared_memory_amount = 0;
1252 dm_stat_need_rcu_barrier = 0;
1253 return 0;
1254}
1255
1256void dm_statistics_exit(void)
1257{
1258 if (dm_stat_need_rcu_barrier)
1259 rcu_barrier();
1260 if (WARN_ON(shared_memory_amount))
1261 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
1262}
1263
1264module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, 0444);
1265MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");
1266

source code of linux/drivers/md/dm-stats.c