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