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/*
70 * A typo on the command line could possibly make the kernel run out of memory
71 * and crash. To prevent the crash we account all used memory. We fail if we
72 * exhaust 1/4 of all memory or 1/2 of vmalloc space.
73 */
74#define DM_STATS_MEMORY_FACTOR 4
75#define DM_STATS_VMALLOC_FACTOR 2
76
77static DEFINE_SPINLOCK(shared_memory_lock);
78
79static unsigned long shared_memory_amount;
80
81static bool __check_shared_memory(size_t alloc_size)
82{
83 size_t a;
84
85 a = shared_memory_amount + alloc_size;
86 if (a < shared_memory_amount)
87 return false;
88 if (a >> PAGE_SHIFT > totalram_pages() / DM_STATS_MEMORY_FACTOR)
89 return false;
90#ifdef CONFIG_MMU
91 if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR)
92 return false;
93#endif
94 return true;
95}
96
97static bool check_shared_memory(size_t alloc_size)
98{
99 bool ret;
100
101 spin_lock_irq(lock: &shared_memory_lock);
102
103 ret = __check_shared_memory(alloc_size);
104
105 spin_unlock_irq(lock: &shared_memory_lock);
106
107 return ret;
108}
109
110static bool claim_shared_memory(size_t alloc_size)
111{
112 spin_lock_irq(lock: &shared_memory_lock);
113
114 if (!__check_shared_memory(alloc_size)) {
115 spin_unlock_irq(lock: &shared_memory_lock);
116 return false;
117 }
118
119 shared_memory_amount += alloc_size;
120
121 spin_unlock_irq(lock: &shared_memory_lock);
122
123 return true;
124}
125
126static void free_shared_memory(size_t alloc_size)
127{
128 unsigned long flags;
129
130 spin_lock_irqsave(&shared_memory_lock, flags);
131
132 if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) {
133 spin_unlock_irqrestore(lock: &shared_memory_lock, flags);
134 DMCRIT("Memory usage accounting bug.");
135 return;
136 }
137
138 shared_memory_amount -= alloc_size;
139
140 spin_unlock_irqrestore(lock: &shared_memory_lock, flags);
141}
142
143static void *dm_kvzalloc(size_t alloc_size, int node)
144{
145 void *p;
146
147 if (!claim_shared_memory(alloc_size))
148 return NULL;
149
150 p = kvzalloc_node(size: alloc_size, GFP_KERNEL | __GFP_NOMEMALLOC, node);
151 if (p)
152 return p;
153
154 free_shared_memory(alloc_size);
155
156 return NULL;
157}
158
159static void dm_kvfree(void *ptr, size_t alloc_size)
160{
161 if (!ptr)
162 return;
163
164 free_shared_memory(alloc_size);
165
166 kvfree(addr: ptr);
167}
168
169static void dm_stat_free(struct rcu_head *head)
170{
171 int cpu;
172 struct dm_stat *s = container_of(head, struct dm_stat, rcu_head);
173
174 kfree(objp: s->histogram_boundaries);
175 kfree(objp: s->program_id);
176 kfree(objp: s->aux_data);
177 for_each_possible_cpu(cpu) {
178 dm_kvfree(ptr: s->stat_percpu[cpu][0].histogram, alloc_size: s->histogram_alloc_size);
179 dm_kvfree(ptr: s->stat_percpu[cpu], alloc_size: s->percpu_alloc_size);
180 }
181 dm_kvfree(ptr: s->stat_shared[0].tmp.histogram, alloc_size: s->histogram_alloc_size);
182 dm_kvfree(ptr: s, alloc_size: s->shared_alloc_size);
183}
184
185static int dm_stat_in_flight(struct dm_stat_shared *shared)
186{
187 return atomic_read(v: &shared->in_flight[READ]) +
188 atomic_read(v: &shared->in_flight[WRITE]);
189}
190
191int dm_stats_init(struct dm_stats *stats)
192{
193 int cpu;
194 struct dm_stats_last_position *last;
195
196 mutex_init(&stats->mutex);
197 INIT_LIST_HEAD(list: &stats->list);
198 stats->precise_timestamps = false;
199 stats->last = alloc_percpu(struct dm_stats_last_position);
200 if (!stats->last)
201 return -ENOMEM;
202
203 for_each_possible_cpu(cpu) {
204 last = per_cpu_ptr(stats->last, cpu);
205 last->last_sector = (sector_t)ULLONG_MAX;
206 last->last_rw = UINT_MAX;
207 }
208
209 return 0;
210}
211
212void dm_stats_cleanup(struct dm_stats *stats)
213{
214 size_t ni;
215 struct dm_stat *s;
216 struct dm_stat_shared *shared;
217
218 while (!list_empty(head: &stats->list)) {
219 s = container_of(stats->list.next, struct dm_stat, list_entry);
220 list_del(entry: &s->list_entry);
221 for (ni = 0; ni < s->n_entries; ni++) {
222 shared = &s->stat_shared[ni];
223 if (WARN_ON(dm_stat_in_flight(shared))) {
224 DMCRIT("leaked in-flight counter at index %lu "
225 "(start %llu, end %llu, step %llu): reads %d, writes %d",
226 (unsigned long)ni,
227 (unsigned long long)s->start,
228 (unsigned long long)s->end,
229 (unsigned long long)s->step,
230 atomic_read(&shared->in_flight[READ]),
231 atomic_read(&shared->in_flight[WRITE]));
232 }
233 cond_resched();
234 }
235 dm_stat_free(head: &s->rcu_head);
236 }
237 free_percpu(pdata: stats->last);
238 mutex_destroy(lock: &stats->mutex);
239}
240
241static void dm_stats_recalc_precise_timestamps(struct dm_stats *stats)
242{
243 struct list_head *l;
244 struct dm_stat *tmp_s;
245 bool precise_timestamps = false;
246
247 list_for_each(l, &stats->list) {
248 tmp_s = container_of(l, struct dm_stat, list_entry);
249 if (tmp_s->stat_flags & STAT_PRECISE_TIMESTAMPS) {
250 precise_timestamps = true;
251 break;
252 }
253 }
254 stats->precise_timestamps = precise_timestamps;
255}
256
257static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
258 sector_t step, unsigned int stat_flags,
259 unsigned int n_histogram_entries,
260 unsigned long long *histogram_boundaries,
261 const char *program_id, const char *aux_data,
262 void (*suspend_callback)(struct mapped_device *),
263 void (*resume_callback)(struct mapped_device *),
264 struct mapped_device *md)
265{
266 struct list_head *l;
267 struct dm_stat *s, *tmp_s;
268 sector_t n_entries;
269 size_t ni;
270 size_t shared_alloc_size;
271 size_t percpu_alloc_size;
272 size_t histogram_alloc_size;
273 struct dm_stat_percpu *p;
274 int cpu;
275 int ret_id;
276 int r;
277
278 if (end < start || !step)
279 return -EINVAL;
280
281 n_entries = end - start;
282 if (dm_sector_div64(n_entries, step))
283 n_entries++;
284
285 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
286 return -EOVERFLOW;
287
288 shared_alloc_size = struct_size(s, stat_shared, n_entries);
289 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
290 return -EOVERFLOW;
291
292 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
293 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
294 return -EOVERFLOW;
295
296 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
297 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
298 return -EOVERFLOW;
299
300 if (!check_shared_memory(alloc_size: shared_alloc_size + histogram_alloc_size +
301 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
302 return -ENOMEM;
303
304 s = dm_kvzalloc(alloc_size: shared_alloc_size, NUMA_NO_NODE);
305 if (!s)
306 return -ENOMEM;
307
308 s->stat_flags = stat_flags;
309 s->n_entries = n_entries;
310 s->start = start;
311 s->end = end;
312 s->step = step;
313 s->shared_alloc_size = shared_alloc_size;
314 s->percpu_alloc_size = percpu_alloc_size;
315 s->histogram_alloc_size = histogram_alloc_size;
316
317 s->n_histogram_entries = n_histogram_entries;
318 s->histogram_boundaries = kmemdup(p: histogram_boundaries,
319 size: s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
320 if (!s->histogram_boundaries) {
321 r = -ENOMEM;
322 goto out;
323 }
324
325 s->program_id = kstrdup(s: program_id, GFP_KERNEL);
326 if (!s->program_id) {
327 r = -ENOMEM;
328 goto out;
329 }
330 s->aux_data = kstrdup(s: aux_data, GFP_KERNEL);
331 if (!s->aux_data) {
332 r = -ENOMEM;
333 goto out;
334 }
335
336 for (ni = 0; ni < n_entries; ni++) {
337 atomic_set(v: &s->stat_shared[ni].in_flight[READ], i: 0);
338 atomic_set(v: &s->stat_shared[ni].in_flight[WRITE], i: 0);
339 cond_resched();
340 }
341
342 if (s->n_histogram_entries) {
343 unsigned long long *hi;
344
345 hi = dm_kvzalloc(alloc_size: s->histogram_alloc_size, NUMA_NO_NODE);
346 if (!hi) {
347 r = -ENOMEM;
348 goto out;
349 }
350 for (ni = 0; ni < n_entries; ni++) {
351 s->stat_shared[ni].tmp.histogram = hi;
352 hi += s->n_histogram_entries + 1;
353 cond_resched();
354 }
355 }
356
357 for_each_possible_cpu(cpu) {
358 p = dm_kvzalloc(alloc_size: percpu_alloc_size, cpu_to_node(cpu));
359 if (!p) {
360 r = -ENOMEM;
361 goto out;
362 }
363 s->stat_percpu[cpu] = p;
364 if (s->n_histogram_entries) {
365 unsigned long long *hi;
366
367 hi = dm_kvzalloc(alloc_size: s->histogram_alloc_size, cpu_to_node(cpu));
368 if (!hi) {
369 r = -ENOMEM;
370 goto out;
371 }
372 for (ni = 0; ni < n_entries; ni++) {
373 p[ni].histogram = hi;
374 hi += s->n_histogram_entries + 1;
375 cond_resched();
376 }
377 }
378 }
379
380 /*
381 * Suspend/resume to make sure there is no i/o in flight,
382 * so that newly created statistics will be exact.
383 *
384 * (note: we couldn't suspend earlier because we must not
385 * allocate memory while suspended)
386 */
387 suspend_callback(md);
388
389 mutex_lock(&stats->mutex);
390 s->id = 0;
391 list_for_each(l, &stats->list) {
392 tmp_s = container_of(l, struct dm_stat, list_entry);
393 if (WARN_ON(tmp_s->id < s->id)) {
394 r = -EINVAL;
395 goto out_unlock_resume;
396 }
397 if (tmp_s->id > s->id)
398 break;
399 if (unlikely(s->id == INT_MAX)) {
400 r = -ENFILE;
401 goto out_unlock_resume;
402 }
403 s->id++;
404 }
405 ret_id = s->id;
406 list_add_tail_rcu(new: &s->list_entry, head: l);
407
408 dm_stats_recalc_precise_timestamps(stats);
409
410 if (!static_key_enabled(&stats_enabled.key))
411 static_branch_enable(&stats_enabled);
412
413 mutex_unlock(lock: &stats->mutex);
414
415 resume_callback(md);
416
417 return ret_id;
418
419out_unlock_resume:
420 mutex_unlock(lock: &stats->mutex);
421 resume_callback(md);
422out:
423 dm_stat_free(head: &s->rcu_head);
424 return r;
425}
426
427static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
428{
429 struct dm_stat *s;
430
431 list_for_each_entry(s, &stats->list, list_entry) {
432 if (s->id > id)
433 break;
434 if (s->id == id)
435 return s;
436 }
437
438 return NULL;
439}
440
441static int dm_stats_delete(struct dm_stats *stats, int id)
442{
443 struct dm_stat *s;
444 int cpu;
445
446 mutex_lock(&stats->mutex);
447
448 s = __dm_stats_find(stats, id);
449 if (!s) {
450 mutex_unlock(lock: &stats->mutex);
451 return -ENOENT;
452 }
453
454 list_del_rcu(entry: &s->list_entry);
455
456 dm_stats_recalc_precise_timestamps(stats);
457
458 mutex_unlock(lock: &stats->mutex);
459
460 /*
461 * vfree can't be called from RCU callback
462 */
463 for_each_possible_cpu(cpu)
464 if (is_vmalloc_addr(x: s->stat_percpu) ||
465 is_vmalloc_addr(x: s->stat_percpu[cpu][0].histogram))
466 goto do_sync_free;
467 if (is_vmalloc_addr(x: s) ||
468 is_vmalloc_addr(x: s->stat_shared[0].tmp.histogram)) {
469do_sync_free:
470 synchronize_rcu_expedited();
471 dm_stat_free(head: &s->rcu_head);
472 } else {
473 WRITE_ONCE(dm_stat_need_rcu_barrier, 1);
474 call_rcu(head: &s->rcu_head, func: dm_stat_free);
475 }
476 return 0;
477}
478
479static int dm_stats_list(struct dm_stats *stats, const char *program,
480 char *result, unsigned int maxlen)
481{
482 struct dm_stat *s;
483 sector_t len;
484 unsigned int sz = 0;
485
486 /*
487 * Output format:
488 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
489 */
490
491 mutex_lock(&stats->mutex);
492 list_for_each_entry(s, &stats->list, list_entry) {
493 if (!program || !strcmp(program, s->program_id)) {
494 len = s->end - s->start;
495 DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
496 (unsigned long long)s->start,
497 (unsigned long long)len,
498 (unsigned long long)s->step,
499 s->program_id,
500 s->aux_data);
501 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
502 DMEMIT(" precise_timestamps");
503 if (s->n_histogram_entries) {
504 unsigned int i;
505
506 DMEMIT(" histogram:");
507 for (i = 0; i < s->n_histogram_entries; i++) {
508 if (i)
509 DMEMIT(",");
510 DMEMIT("%llu", s->histogram_boundaries[i]);
511 }
512 }
513 DMEMIT("\n");
514 }
515 cond_resched();
516 }
517 mutex_unlock(lock: &stats->mutex);
518
519 return 1;
520}
521
522static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
523 struct dm_stat_percpu *p)
524{
525 /*
526 * This is racy, but so is part_round_stats_single.
527 */
528 unsigned long long now, difference;
529 unsigned int in_flight_read, in_flight_write;
530
531 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
532 now = jiffies;
533 else
534 now = ktime_to_ns(kt: ktime_get());
535
536 difference = now - shared->stamp;
537 if (!difference)
538 return;
539
540 in_flight_read = (unsigned int)atomic_read(v: &shared->in_flight[READ]);
541 in_flight_write = (unsigned int)atomic_read(v: &shared->in_flight[WRITE]);
542 if (in_flight_read)
543 p->io_ticks[READ] += difference;
544 if (in_flight_write)
545 p->io_ticks[WRITE] += difference;
546 if (in_flight_read + in_flight_write) {
547 p->io_ticks_total += difference;
548 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
549 }
550 shared->stamp = now;
551}
552
553static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
554 int idx, sector_t len,
555 struct dm_stats_aux *stats_aux, bool end,
556 unsigned long duration_jiffies)
557{
558 struct dm_stat_shared *shared = &s->stat_shared[entry];
559 struct dm_stat_percpu *p;
560
561 /*
562 * For strict correctness we should use local_irq_save/restore
563 * instead of preempt_disable/enable.
564 *
565 * preempt_disable/enable is racy if the driver finishes bios
566 * from non-interrupt context as well as from interrupt context
567 * or from more different interrupts.
568 *
569 * On 64-bit architectures the race only results in not counting some
570 * events, so it is acceptable. On 32-bit architectures the race could
571 * cause the counter going off by 2^32, so we need to do proper locking
572 * there.
573 *
574 * part_stat_lock()/part_stat_unlock() have this race too.
575 */
576#if BITS_PER_LONG == 32
577 unsigned long flags;
578
579 local_irq_save(flags);
580#else
581 preempt_disable();
582#endif
583 p = &s->stat_percpu[smp_processor_id()][entry];
584
585 if (!end) {
586 dm_stat_round(s, shared, p);
587 atomic_inc(v: &shared->in_flight[idx]);
588 } else {
589 unsigned long long duration;
590
591 dm_stat_round(s, shared, p);
592 atomic_dec(v: &shared->in_flight[idx]);
593 p->sectors[idx] += len;
594 p->ios[idx] += 1;
595 p->merges[idx] += stats_aux->merged;
596 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
597 p->ticks[idx] += duration_jiffies;
598 duration = jiffies_to_msecs(j: duration_jiffies);
599 } else {
600 p->ticks[idx] += stats_aux->duration_ns;
601 duration = stats_aux->duration_ns;
602 }
603 if (s->n_histogram_entries) {
604 unsigned int lo = 0, hi = s->n_histogram_entries + 1;
605
606 while (lo + 1 < hi) {
607 unsigned int mid = (lo + hi) / 2;
608
609 if (s->histogram_boundaries[mid - 1] > duration)
610 hi = mid;
611 else
612 lo = mid;
613 }
614 p->histogram[lo]++;
615 }
616 }
617
618#if BITS_PER_LONG == 32
619 local_irq_restore(flags);
620#else
621 preempt_enable();
622#endif
623}
624
625static void __dm_stat_bio(struct dm_stat *s, int bi_rw,
626 sector_t bi_sector, sector_t end_sector,
627 bool end, unsigned long duration_jiffies,
628 struct dm_stats_aux *stats_aux)
629{
630 sector_t rel_sector, offset, todo, fragment_len;
631 size_t entry;
632
633 if (end_sector <= s->start || bi_sector >= s->end)
634 return;
635 if (unlikely(bi_sector < s->start)) {
636 rel_sector = 0;
637 todo = end_sector - s->start;
638 } else {
639 rel_sector = bi_sector - s->start;
640 todo = end_sector - bi_sector;
641 }
642 if (unlikely(end_sector > s->end))
643 todo -= (end_sector - s->end);
644
645 offset = dm_sector_div64(rel_sector, s->step);
646 entry = rel_sector;
647 do {
648 if (WARN_ON_ONCE(entry >= s->n_entries)) {
649 DMCRIT("Invalid area access in region id %d", s->id);
650 return;
651 }
652 fragment_len = todo;
653 if (fragment_len > s->step - offset)
654 fragment_len = s->step - offset;
655 dm_stat_for_entry(s, entry, idx: bi_rw, len: fragment_len,
656 stats_aux, end, duration_jiffies);
657 todo -= fragment_len;
658 entry++;
659 offset = 0;
660 } while (unlikely(todo != 0));
661}
662
663void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
664 sector_t bi_sector, unsigned int bi_sectors, bool end,
665 unsigned long start_time,
666 struct dm_stats_aux *stats_aux)
667{
668 struct dm_stat *s;
669 sector_t end_sector;
670 struct dm_stats_last_position *last;
671 bool got_precise_time;
672 unsigned long duration_jiffies = 0;
673
674 if (unlikely(!bi_sectors))
675 return;
676
677 end_sector = bi_sector + bi_sectors;
678
679 if (!end) {
680 /*
681 * A race condition can at worst result in the merged flag being
682 * misrepresented, so we don't have to disable preemption here.
683 */
684 last = raw_cpu_ptr(stats->last);
685 stats_aux->merged =
686 (bi_sector == (READ_ONCE(last->last_sector) &&
687 ((bi_rw == WRITE) ==
688 (READ_ONCE(last->last_rw) == WRITE))
689 ));
690 WRITE_ONCE(last->last_sector, end_sector);
691 WRITE_ONCE(last->last_rw, bi_rw);
692 } else
693 duration_jiffies = jiffies - start_time;
694
695 rcu_read_lock();
696
697 got_precise_time = false;
698 list_for_each_entry_rcu(s, &stats->list, list_entry) {
699 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {
700 /* start (!end) duration_ns is set by DM core's alloc_io() */
701 if (end)
702 stats_aux->duration_ns = ktime_to_ns(kt: ktime_get()) - stats_aux->duration_ns;
703 got_precise_time = true;
704 }
705 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
706 }
707
708 rcu_read_unlock();
709}
710
711static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
712 struct dm_stat *s, size_t x)
713{
714 int cpu;
715 struct dm_stat_percpu *p;
716
717 local_irq_disable();
718 p = &s->stat_percpu[smp_processor_id()][x];
719 dm_stat_round(s, shared, p);
720 local_irq_enable();
721
722 shared->tmp.sectors[READ] = 0;
723 shared->tmp.sectors[WRITE] = 0;
724 shared->tmp.ios[READ] = 0;
725 shared->tmp.ios[WRITE] = 0;
726 shared->tmp.merges[READ] = 0;
727 shared->tmp.merges[WRITE] = 0;
728 shared->tmp.ticks[READ] = 0;
729 shared->tmp.ticks[WRITE] = 0;
730 shared->tmp.io_ticks[READ] = 0;
731 shared->tmp.io_ticks[WRITE] = 0;
732 shared->tmp.io_ticks_total = 0;
733 shared->tmp.time_in_queue = 0;
734
735 if (s->n_histogram_entries)
736 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
737
738 for_each_possible_cpu(cpu) {
739 p = &s->stat_percpu[cpu][x];
740 shared->tmp.sectors[READ] += READ_ONCE(p->sectors[READ]);
741 shared->tmp.sectors[WRITE] += READ_ONCE(p->sectors[WRITE]);
742 shared->tmp.ios[READ] += READ_ONCE(p->ios[READ]);
743 shared->tmp.ios[WRITE] += READ_ONCE(p->ios[WRITE]);
744 shared->tmp.merges[READ] += READ_ONCE(p->merges[READ]);
745 shared->tmp.merges[WRITE] += READ_ONCE(p->merges[WRITE]);
746 shared->tmp.ticks[READ] += READ_ONCE(p->ticks[READ]);
747 shared->tmp.ticks[WRITE] += READ_ONCE(p->ticks[WRITE]);
748 shared->tmp.io_ticks[READ] += READ_ONCE(p->io_ticks[READ]);
749 shared->tmp.io_ticks[WRITE] += READ_ONCE(p->io_ticks[WRITE]);
750 shared->tmp.io_ticks_total += READ_ONCE(p->io_ticks_total);
751 shared->tmp.time_in_queue += READ_ONCE(p->time_in_queue);
752 if (s->n_histogram_entries) {
753 unsigned int i;
754
755 for (i = 0; i < s->n_histogram_entries + 1; i++)
756 shared->tmp.histogram[i] += READ_ONCE(p->histogram[i]);
757 }
758 }
759}
760
761static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
762 bool init_tmp_percpu_totals)
763{
764 size_t x;
765 struct dm_stat_shared *shared;
766 struct dm_stat_percpu *p;
767
768 for (x = idx_start; x < idx_end; x++) {
769 shared = &s->stat_shared[x];
770 if (init_tmp_percpu_totals)
771 __dm_stat_init_temporary_percpu_totals(shared, s, x);
772 local_irq_disable();
773 p = &s->stat_percpu[smp_processor_id()][x];
774 p->sectors[READ] -= shared->tmp.sectors[READ];
775 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
776 p->ios[READ] -= shared->tmp.ios[READ];
777 p->ios[WRITE] -= shared->tmp.ios[WRITE];
778 p->merges[READ] -= shared->tmp.merges[READ];
779 p->merges[WRITE] -= shared->tmp.merges[WRITE];
780 p->ticks[READ] -= shared->tmp.ticks[READ];
781 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
782 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
783 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
784 p->io_ticks_total -= shared->tmp.io_ticks_total;
785 p->time_in_queue -= shared->tmp.time_in_queue;
786 local_irq_enable();
787 if (s->n_histogram_entries) {
788 unsigned int i;
789
790 for (i = 0; i < s->n_histogram_entries + 1; i++) {
791 local_irq_disable();
792 p = &s->stat_percpu[smp_processor_id()][x];
793 p->histogram[i] -= shared->tmp.histogram[i];
794 local_irq_enable();
795 }
796 }
797 cond_resched();
798 }
799}
800
801static int dm_stats_clear(struct dm_stats *stats, int id)
802{
803 struct dm_stat *s;
804
805 mutex_lock(&stats->mutex);
806
807 s = __dm_stats_find(stats, id);
808 if (!s) {
809 mutex_unlock(lock: &stats->mutex);
810 return -ENOENT;
811 }
812
813 __dm_stat_clear(s, idx_start: 0, idx_end: s->n_entries, init_tmp_percpu_totals: true);
814
815 mutex_unlock(lock: &stats->mutex);
816
817 return 1;
818}
819
820/*
821 * This is like jiffies_to_msec, but works for 64-bit values.
822 */
823static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
824{
825 unsigned long long result;
826 unsigned int mult;
827
828 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
829 return j;
830
831 result = 0;
832 if (j)
833 result = jiffies_to_msecs(j: j & 0x3fffff);
834 if (j >= 1 << 22) {
835 mult = jiffies_to_msecs(j: 1 << 22);
836 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j: (j >> 22) & 0x3fffff);
837 }
838 if (j >= 1ULL << 44)
839 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j: j >> 44);
840
841 return result;
842}
843
844static int dm_stats_print(struct dm_stats *stats, int id,
845 size_t idx_start, size_t idx_len,
846 bool clear, char *result, unsigned int maxlen)
847{
848 unsigned int sz = 0;
849 struct dm_stat *s;
850 size_t x;
851 sector_t start, end, step;
852 size_t idx_end;
853 struct dm_stat_shared *shared;
854
855 /*
856 * Output format:
857 * <start_sector>+<length> counters
858 */
859
860 mutex_lock(&stats->mutex);
861
862 s = __dm_stats_find(stats, id);
863 if (!s) {
864 mutex_unlock(lock: &stats->mutex);
865 return -ENOENT;
866 }
867
868 idx_end = idx_start + idx_len;
869 if (idx_end < idx_start ||
870 idx_end > s->n_entries)
871 idx_end = s->n_entries;
872
873 if (idx_start > idx_end)
874 idx_start = idx_end;
875
876 step = s->step;
877 start = s->start + (step * idx_start);
878
879 for (x = idx_start; x < idx_end; x++, start = end) {
880 shared = &s->stat_shared[x];
881 end = start + step;
882 if (unlikely(end > s->end))
883 end = s->end;
884
885 __dm_stat_init_temporary_percpu_totals(shared, s, x);
886
887 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",
888 (unsigned long long)start,
889 (unsigned long long)step,
890 shared->tmp.ios[READ],
891 shared->tmp.merges[READ],
892 shared->tmp.sectors[READ],
893 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),
894 shared->tmp.ios[WRITE],
895 shared->tmp.merges[WRITE],
896 shared->tmp.sectors[WRITE],
897 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),
898 dm_stat_in_flight(shared),
899 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),
900 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),
901 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),
902 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));
903 if (s->n_histogram_entries) {
904 unsigned int i;
905
906 for (i = 0; i < s->n_histogram_entries + 1; i++)
907 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
908 }
909 DMEMIT("\n");
910
911 if (unlikely(sz + 1 >= maxlen))
912 goto buffer_overflow;
913
914 cond_resched();
915 }
916
917 if (clear)
918 __dm_stat_clear(s, idx_start, idx_end, init_tmp_percpu_totals: false);
919
920buffer_overflow:
921 mutex_unlock(lock: &stats->mutex);
922
923 return 1;
924}
925
926static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
927{
928 struct dm_stat *s;
929 const char *new_aux_data;
930
931 mutex_lock(&stats->mutex);
932
933 s = __dm_stats_find(stats, id);
934 if (!s) {
935 mutex_unlock(lock: &stats->mutex);
936 return -ENOENT;
937 }
938
939 new_aux_data = kstrdup(s: aux_data, GFP_KERNEL);
940 if (!new_aux_data) {
941 mutex_unlock(lock: &stats->mutex);
942 return -ENOMEM;
943 }
944
945 kfree(objp: s->aux_data);
946 s->aux_data = new_aux_data;
947
948 mutex_unlock(lock: &stats->mutex);
949
950 return 0;
951}
952
953static int parse_histogram(const char *h, unsigned int *n_histogram_entries,
954 unsigned long long **histogram_boundaries)
955{
956 const char *q;
957 unsigned int n;
958 unsigned long long last;
959
960 *n_histogram_entries = 1;
961 for (q = h; *q; q++)
962 if (*q == ',')
963 (*n_histogram_entries)++;
964
965 *histogram_boundaries = kmalloc_array(n: *n_histogram_entries,
966 size: sizeof(unsigned long long),
967 GFP_KERNEL);
968 if (!*histogram_boundaries)
969 return -ENOMEM;
970
971 n = 0;
972 last = 0;
973 while (1) {
974 unsigned long long hi;
975 int s;
976 char ch;
977
978 s = sscanf(h, "%llu%c", &hi, &ch);
979 if (!s || (s == 2 && ch != ','))
980 return -EINVAL;
981 if (hi <= last)
982 return -EINVAL;
983 last = hi;
984 (*histogram_boundaries)[n] = hi;
985 if (s == 1)
986 return 0;
987 h = strchr(h, ',') + 1;
988 n++;
989 }
990}
991
992static int message_stats_create(struct mapped_device *md,
993 unsigned int argc, char **argv,
994 char *result, unsigned int maxlen)
995{
996 int r;
997 int id;
998 char dummy;
999 unsigned long long start, end, len, step;
1000 unsigned int divisor;
1001 const char *program_id, *aux_data;
1002 unsigned int stat_flags = 0;
1003 unsigned int n_histogram_entries = 0;
1004 unsigned long long *histogram_boundaries = NULL;
1005 struct dm_arg_set as, as_backup;
1006 const char *a;
1007 unsigned int feature_args;
1008
1009 /*
1010 * Input format:
1011 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
1012 */
1013
1014 if (argc < 3)
1015 goto ret_einval;
1016
1017 as.argc = argc;
1018 as.argv = argv;
1019 dm_consume_args(as: &as, num_args: 1);
1020
1021 a = dm_shift_arg(as: &as);
1022 if (!strcmp(a, "-")) {
1023 start = 0;
1024 len = dm_get_size(md);
1025 if (!len)
1026 len = 1;
1027 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
1028 start != (sector_t)start || len != (sector_t)len)
1029 goto ret_einval;
1030
1031 end = start + len;
1032 if (start >= end)
1033 goto ret_einval;
1034
1035 a = dm_shift_arg(as: &as);
1036 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
1037 if (!divisor)
1038 return -EINVAL;
1039 step = end - start;
1040 if (do_div(step, divisor))
1041 step++;
1042 if (!step)
1043 step = 1;
1044 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
1045 step != (sector_t)step || !step)
1046 goto ret_einval;
1047
1048 as_backup = as;
1049 a = dm_shift_arg(as: &as);
1050 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
1051 while (feature_args--) {
1052 a = dm_shift_arg(as: &as);
1053 if (!a)
1054 goto ret_einval;
1055 if (!strcasecmp(s1: a, s2: "precise_timestamps"))
1056 stat_flags |= STAT_PRECISE_TIMESTAMPS;
1057 else if (!strncasecmp(s1: a, s2: "histogram:", n: 10)) {
1058 if (n_histogram_entries)
1059 goto ret_einval;
1060 r = parse_histogram(h: a + 10, n_histogram_entries: &n_histogram_entries, histogram_boundaries: &histogram_boundaries);
1061 if (r)
1062 goto ret;
1063 } else
1064 goto ret_einval;
1065 }
1066 } else {
1067 as = as_backup;
1068 }
1069
1070 program_id = "-";
1071 aux_data = "-";
1072
1073 a = dm_shift_arg(as: &as);
1074 if (a)
1075 program_id = a;
1076
1077 a = dm_shift_arg(as: &as);
1078 if (a)
1079 aux_data = a;
1080
1081 if (as.argc)
1082 goto ret_einval;
1083
1084 /*
1085 * If a buffer overflow happens after we created the region,
1086 * it's too late (the userspace would retry with a larger
1087 * buffer, but the region id that caused the overflow is already
1088 * leaked). So we must detect buffer overflow in advance.
1089 */
1090 snprintf(buf: result, size: maxlen, fmt: "%d", INT_MAX);
1091 if (dm_message_test_buffer_overflow(result, maxlen)) {
1092 r = 1;
1093 goto ret;
1094 }
1095
1096 id = dm_stats_create(stats: dm_get_stats(md), start, end, step, stat_flags,
1097 n_histogram_entries, histogram_boundaries, program_id, aux_data,
1098 suspend_callback: dm_internal_suspend_fast, resume_callback: dm_internal_resume_fast, md);
1099 if (id < 0) {
1100 r = id;
1101 goto ret;
1102 }
1103
1104 snprintf(buf: result, size: maxlen, fmt: "%d", id);
1105
1106 r = 1;
1107 goto ret;
1108
1109ret_einval:
1110 r = -EINVAL;
1111ret:
1112 kfree(objp: histogram_boundaries);
1113 return r;
1114}
1115
1116static int message_stats_delete(struct mapped_device *md,
1117 unsigned int argc, char **argv)
1118{
1119 int id;
1120 char dummy;
1121
1122 if (argc != 2)
1123 return -EINVAL;
1124
1125 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1126 return -EINVAL;
1127
1128 return dm_stats_delete(stats: dm_get_stats(md), id);
1129}
1130
1131static int message_stats_clear(struct mapped_device *md,
1132 unsigned int argc, char **argv)
1133{
1134 int id;
1135 char dummy;
1136
1137 if (argc != 2)
1138 return -EINVAL;
1139
1140 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1141 return -EINVAL;
1142
1143 return dm_stats_clear(stats: dm_get_stats(md), id);
1144}
1145
1146static int message_stats_list(struct mapped_device *md,
1147 unsigned int argc, char **argv,
1148 char *result, unsigned int maxlen)
1149{
1150 int r;
1151 const char *program = NULL;
1152
1153 if (argc < 1 || argc > 2)
1154 return -EINVAL;
1155
1156 if (argc > 1) {
1157 program = kstrdup(s: argv[1], GFP_KERNEL);
1158 if (!program)
1159 return -ENOMEM;
1160 }
1161
1162 r = dm_stats_list(stats: dm_get_stats(md), program, result, maxlen);
1163
1164 kfree(objp: program);
1165
1166 return r;
1167}
1168
1169static int message_stats_print(struct mapped_device *md,
1170 unsigned int argc, char **argv, bool clear,
1171 char *result, unsigned int maxlen)
1172{
1173 int id;
1174 char dummy;
1175 unsigned long idx_start = 0, idx_len = ULONG_MAX;
1176
1177 if (argc != 2 && argc != 4)
1178 return -EINVAL;
1179
1180 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1181 return -EINVAL;
1182
1183 if (argc > 3) {
1184 if (strcmp(argv[2], "-") &&
1185 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
1186 return -EINVAL;
1187 if (strcmp(argv[3], "-") &&
1188 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
1189 return -EINVAL;
1190 }
1191
1192 return dm_stats_print(stats: dm_get_stats(md), id, idx_start, idx_len, clear,
1193 result, maxlen);
1194}
1195
1196static int message_stats_set_aux(struct mapped_device *md,
1197 unsigned int argc, char **argv)
1198{
1199 int id;
1200 char dummy;
1201
1202 if (argc != 3)
1203 return -EINVAL;
1204
1205 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
1206 return -EINVAL;
1207
1208 return dm_stats_set_aux(stats: dm_get_stats(md), id, aux_data: argv[2]);
1209}
1210
1211int dm_stats_message(struct mapped_device *md, unsigned int argc, char **argv,
1212 char *result, unsigned int maxlen)
1213{
1214 int r;
1215
1216 /* All messages here must start with '@' */
1217 if (!strcasecmp(s1: argv[0], s2: "@stats_create"))
1218 r = message_stats_create(md, argc, argv, result, maxlen);
1219 else if (!strcasecmp(s1: argv[0], s2: "@stats_delete"))
1220 r = message_stats_delete(md, argc, argv);
1221 else if (!strcasecmp(s1: argv[0], s2: "@stats_clear"))
1222 r = message_stats_clear(md, argc, argv);
1223 else if (!strcasecmp(s1: argv[0], s2: "@stats_list"))
1224 r = message_stats_list(md, argc, argv, result, maxlen);
1225 else if (!strcasecmp(s1: argv[0], s2: "@stats_print"))
1226 r = message_stats_print(md, argc, argv, clear: false, result, maxlen);
1227 else if (!strcasecmp(s1: argv[0], s2: "@stats_print_clear"))
1228 r = message_stats_print(md, argc, argv, clear: true, result, maxlen);
1229 else if (!strcasecmp(s1: argv[0], s2: "@stats_set_aux"))
1230 r = message_stats_set_aux(md, argc, argv);
1231 else
1232 return 2; /* this wasn't a stats message */
1233
1234 if (r == -EINVAL)
1235 DMCRIT("Invalid parameters for message %s", argv[0]);
1236
1237 return r;
1238}
1239
1240int __init dm_statistics_init(void)
1241{
1242 shared_memory_amount = 0;
1243 dm_stat_need_rcu_barrier = 0;
1244 return 0;
1245}
1246
1247void dm_statistics_exit(void)
1248{
1249 if (dm_stat_need_rcu_barrier)
1250 rcu_barrier();
1251 if (WARN_ON(shared_memory_amount))
1252 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
1253}
1254
1255module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, 0444);
1256MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");
1257

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