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-rw-r--r--drivers/md/dm-stats.c969
1 files changed, 969 insertions, 0 deletions
diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c
new file mode 100644
index 000000000000..8ae31e8d3d64
--- /dev/null
+++ b/drivers/md/dm-stats.c
@@ -0,0 +1,969 @@
1#include <linux/errno.h>
2#include <linux/numa.h>
3#include <linux/slab.h>
4#include <linux/rculist.h>
5#include <linux/threads.h>
6#include <linux/preempt.h>
7#include <linux/irqflags.h>
8#include <linux/vmalloc.h>
9#include <linux/mm.h>
10#include <linux/module.h>
11#include <linux/device-mapper.h>
12
13#include "dm.h"
14#include "dm-stats.h"
15
16#define DM_MSG_PREFIX "stats"
17
18static int dm_stat_need_rcu_barrier;
19
20/*
21 * Using 64-bit values to avoid overflow (which is a
22 * problem that block/genhd.c's IO accounting has).
23 */
24struct dm_stat_percpu {
25 unsigned long long sectors[2];
26 unsigned long long ios[2];
27 unsigned long long merges[2];
28 unsigned long long ticks[2];
29 unsigned long long io_ticks[2];
30 unsigned long long io_ticks_total;
31 unsigned long long time_in_queue;
32};
33
34struct dm_stat_shared {
35 atomic_t in_flight[2];
36 unsigned long stamp;
37 struct dm_stat_percpu tmp;
38};
39
40struct dm_stat {
41 struct list_head list_entry;
42 int id;
43 size_t n_entries;
44 sector_t start;
45 sector_t end;
46 sector_t step;
47 const char *program_id;
48 const char *aux_data;
49 struct rcu_head rcu_head;
50 size_t shared_alloc_size;
51 size_t percpu_alloc_size;
52 struct dm_stat_percpu *stat_percpu[NR_CPUS];
53 struct dm_stat_shared stat_shared[0];
54};
55
56struct dm_stats_last_position {
57 sector_t last_sector;
58 unsigned last_rw;
59};
60
61/*
62 * A typo on the command line could possibly make the kernel run out of memory
63 * and crash. To prevent the crash we account all used memory. We fail if we
64 * exhaust 1/4 of all memory or 1/2 of vmalloc space.
65 */
66#define DM_STATS_MEMORY_FACTOR 4
67#define DM_STATS_VMALLOC_FACTOR 2
68
69static DEFINE_SPINLOCK(shared_memory_lock);
70
71static unsigned long shared_memory_amount;
72
73static bool __check_shared_memory(size_t alloc_size)
74{
75 size_t a;
76
77 a = shared_memory_amount + alloc_size;
78 if (a < shared_memory_amount)
79 return false;
80 if (a >> PAGE_SHIFT > totalram_pages / DM_STATS_MEMORY_FACTOR)
81 return false;
82#ifdef CONFIG_MMU
83 if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR)
84 return false;
85#endif
86 return true;
87}
88
89static bool check_shared_memory(size_t alloc_size)
90{
91 bool ret;
92
93 spin_lock_irq(&shared_memory_lock);
94
95 ret = __check_shared_memory(alloc_size);
96
97 spin_unlock_irq(&shared_memory_lock);
98
99 return ret;
100}
101
102static bool claim_shared_memory(size_t alloc_size)
103{
104 spin_lock_irq(&shared_memory_lock);
105
106 if (!__check_shared_memory(alloc_size)) {
107 spin_unlock_irq(&shared_memory_lock);
108 return false;
109 }
110
111 shared_memory_amount += alloc_size;
112
113 spin_unlock_irq(&shared_memory_lock);
114
115 return true;
116}
117
118static void free_shared_memory(size_t alloc_size)
119{
120 unsigned long flags;
121
122 spin_lock_irqsave(&shared_memory_lock, flags);
123
124 if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) {
125 spin_unlock_irqrestore(&shared_memory_lock, flags);
126 DMCRIT("Memory usage accounting bug.");
127 return;
128 }
129
130 shared_memory_amount -= alloc_size;
131
132 spin_unlock_irqrestore(&shared_memory_lock, flags);
133}
134
135static void *dm_kvzalloc(size_t alloc_size, int node)
136{
137 void *p;
138
139 if (!claim_shared_memory(alloc_size))
140 return NULL;
141
142 if (alloc_size <= KMALLOC_MAX_SIZE) {
143 p = kzalloc_node(alloc_size, GFP_KERNEL | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN, node);
144 if (p)
145 return p;
146 }
147 p = vzalloc_node(alloc_size, node);
148 if (p)
149 return p;
150
151 free_shared_memory(alloc_size);
152
153 return NULL;
154}
155
156static void dm_kvfree(void *ptr, size_t alloc_size)
157{
158 if (!ptr)
159 return;
160
161 free_shared_memory(alloc_size);
162
163 if (is_vmalloc_addr(ptr))
164 vfree(ptr);
165 else
166 kfree(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(s->program_id);
175 kfree(s->aux_data);
176 for_each_possible_cpu(cpu)
177 dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size);
178 dm_kvfree(s, s->shared_alloc_size);
179}
180
181static int dm_stat_in_flight(struct dm_stat_shared *shared)
182{
183 return atomic_read(&shared->in_flight[READ]) +
184 atomic_read(&shared->in_flight[WRITE]);
185}
186
187void dm_stats_init(struct dm_stats *stats)
188{
189 int cpu;
190 struct dm_stats_last_position *last;
191
192 mutex_init(&stats->mutex);
193 INIT_LIST_HEAD(&stats->list);
194 stats->last = alloc_percpu(struct dm_stats_last_position);
195 for_each_possible_cpu(cpu) {
196 last = per_cpu_ptr(stats->last, cpu);
197 last->last_sector = (sector_t)ULLONG_MAX;
198 last->last_rw = UINT_MAX;
199 }
200}
201
202void dm_stats_cleanup(struct dm_stats *stats)
203{
204 size_t ni;
205 struct dm_stat *s;
206 struct dm_stat_shared *shared;
207
208 while (!list_empty(&stats->list)) {
209 s = container_of(stats->list.next, struct dm_stat, list_entry);
210 list_del(&s->list_entry);
211 for (ni = 0; ni < s->n_entries; ni++) {
212 shared = &s->stat_shared[ni];
213 if (WARN_ON(dm_stat_in_flight(shared))) {
214 DMCRIT("leaked in-flight counter at index %lu "
215 "(start %llu, end %llu, step %llu): reads %d, writes %d",
216 (unsigned long)ni,
217 (unsigned long long)s->start,
218 (unsigned long long)s->end,
219 (unsigned long long)s->step,
220 atomic_read(&shared->in_flight[READ]),
221 atomic_read(&shared->in_flight[WRITE]));
222 }
223 }
224 dm_stat_free(&s->rcu_head);
225 }
226 free_percpu(stats->last);
227}
228
229static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
230 sector_t step, const char *program_id, const char *aux_data,
231 void (*suspend_callback)(struct mapped_device *),
232 void (*resume_callback)(struct mapped_device *),
233 struct mapped_device *md)
234{
235 struct list_head *l;
236 struct dm_stat *s, *tmp_s;
237 sector_t n_entries;
238 size_t ni;
239 size_t shared_alloc_size;
240 size_t percpu_alloc_size;
241 struct dm_stat_percpu *p;
242 int cpu;
243 int ret_id;
244 int r;
245
246 if (end < start || !step)
247 return -EINVAL;
248
249 n_entries = end - start;
250 if (dm_sector_div64(n_entries, step))
251 n_entries++;
252
253 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
254 return -EOVERFLOW;
255
256 shared_alloc_size = sizeof(struct dm_stat) + (size_t)n_entries * sizeof(struct dm_stat_shared);
257 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
258 return -EOVERFLOW;
259
260 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
261 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
262 return -EOVERFLOW;
263
264 if (!check_shared_memory(shared_alloc_size + num_possible_cpus() * percpu_alloc_size))
265 return -ENOMEM;
266
267 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
268 if (!s)
269 return -ENOMEM;
270
271 s->n_entries = n_entries;
272 s->start = start;
273 s->end = end;
274 s->step = step;
275 s->shared_alloc_size = shared_alloc_size;
276 s->percpu_alloc_size = percpu_alloc_size;
277
278 s->program_id = kstrdup(program_id, GFP_KERNEL);
279 if (!s->program_id) {
280 r = -ENOMEM;
281 goto out;
282 }
283 s->aux_data = kstrdup(aux_data, GFP_KERNEL);
284 if (!s->aux_data) {
285 r = -ENOMEM;
286 goto out;
287 }
288
289 for (ni = 0; ni < n_entries; ni++) {
290 atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
291 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);
292 }
293
294 for_each_possible_cpu(cpu) {
295 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
296 if (!p) {
297 r = -ENOMEM;
298 goto out;
299 }
300 s->stat_percpu[cpu] = p;
301 }
302
303 /*
304 * Suspend/resume to make sure there is no i/o in flight,
305 * so that newly created statistics will be exact.
306 *
307 * (note: we couldn't suspend earlier because we must not
308 * allocate memory while suspended)
309 */
310 suspend_callback(md);
311
312 mutex_lock(&stats->mutex);
313 s->id = 0;
314 list_for_each(l, &stats->list) {
315 tmp_s = container_of(l, struct dm_stat, list_entry);
316 if (WARN_ON(tmp_s->id < s->id)) {
317 r = -EINVAL;
318 goto out_unlock_resume;
319 }
320 if (tmp_s->id > s->id)
321 break;
322 if (unlikely(s->id == INT_MAX)) {
323 r = -ENFILE;
324 goto out_unlock_resume;
325 }
326 s->id++;
327 }
328 ret_id = s->id;
329 list_add_tail_rcu(&s->list_entry, l);
330 mutex_unlock(&stats->mutex);
331
332 resume_callback(md);
333
334 return ret_id;
335
336out_unlock_resume:
337 mutex_unlock(&stats->mutex);
338 resume_callback(md);
339out:
340 dm_stat_free(&s->rcu_head);
341 return r;
342}
343
344static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
345{
346 struct dm_stat *s;
347
348 list_for_each_entry(s, &stats->list, list_entry) {
349 if (s->id > id)
350 break;
351 if (s->id == id)
352 return s;
353 }
354
355 return NULL;
356}
357
358static int dm_stats_delete(struct dm_stats *stats, int id)
359{
360 struct dm_stat *s;
361 int cpu;
362
363 mutex_lock(&stats->mutex);
364
365 s = __dm_stats_find(stats, id);
366 if (!s) {
367 mutex_unlock(&stats->mutex);
368 return -ENOENT;
369 }
370
371 list_del_rcu(&s->list_entry);
372 mutex_unlock(&stats->mutex);
373
374 /*
375 * vfree can't be called from RCU callback
376 */
377 for_each_possible_cpu(cpu)
378 if (is_vmalloc_addr(s->stat_percpu))
379 goto do_sync_free;
380 if (is_vmalloc_addr(s)) {
381do_sync_free:
382 synchronize_rcu_expedited();
383 dm_stat_free(&s->rcu_head);
384 } else {
385 ACCESS_ONCE(dm_stat_need_rcu_barrier) = 1;
386 call_rcu(&s->rcu_head, dm_stat_free);
387 }
388 return 0;
389}
390
391static int dm_stats_list(struct dm_stats *stats, const char *program,
392 char *result, unsigned maxlen)
393{
394 struct dm_stat *s;
395 sector_t len;
396 unsigned sz = 0;
397
398 /*
399 * Output format:
400 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
401 */
402
403 mutex_lock(&stats->mutex);
404 list_for_each_entry(s, &stats->list, list_entry) {
405 if (!program || !strcmp(program, s->program_id)) {
406 len = s->end - s->start;
407 DMEMIT("%d: %llu+%llu %llu %s %s\n", s->id,
408 (unsigned long long)s->start,
409 (unsigned long long)len,
410 (unsigned long long)s->step,
411 s->program_id,
412 s->aux_data);
413 }
414 }
415 mutex_unlock(&stats->mutex);
416
417 return 1;
418}
419
420static void dm_stat_round(struct dm_stat_shared *shared, struct dm_stat_percpu *p)
421{
422 /*
423 * This is racy, but so is part_round_stats_single.
424 */
425 unsigned long now = jiffies;
426 unsigned in_flight_read;
427 unsigned in_flight_write;
428 unsigned long difference = now - shared->stamp;
429
430 if (!difference)
431 return;
432 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]);
433 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]);
434 if (in_flight_read)
435 p->io_ticks[READ] += difference;
436 if (in_flight_write)
437 p->io_ticks[WRITE] += difference;
438 if (in_flight_read + in_flight_write) {
439 p->io_ticks_total += difference;
440 p->time_in_queue += (in_flight_read + in_flight_write) * difference;
441 }
442 shared->stamp = now;
443}
444
445static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
446 unsigned long bi_rw, sector_t len, bool merged,
447 bool end, unsigned long duration)
448{
449 unsigned long idx = bi_rw & REQ_WRITE;
450 struct dm_stat_shared *shared = &s->stat_shared[entry];
451 struct dm_stat_percpu *p;
452
453 /*
454 * For strict correctness we should use local_irq_disable/enable
455 * instead of preempt_disable/enable.
456 *
457 * This is racy if the driver finishes bios from non-interrupt
458 * context as well as from interrupt context or from more different
459 * interrupts.
460 *
461 * However, the race only results in not counting some events,
462 * so it is acceptable.
463 *
464 * part_stat_lock()/part_stat_unlock() have this race too.
465 */
466 preempt_disable();
467 p = &s->stat_percpu[smp_processor_id()][entry];
468
469 if (!end) {
470 dm_stat_round(shared, p);
471 atomic_inc(&shared->in_flight[idx]);
472 } else {
473 dm_stat_round(shared, p);
474 atomic_dec(&shared->in_flight[idx]);
475 p->sectors[idx] += len;
476 p->ios[idx] += 1;
477 p->merges[idx] += merged;
478 p->ticks[idx] += duration;
479 }
480
481 preempt_enable();
482}
483
484static void __dm_stat_bio(struct dm_stat *s, unsigned long bi_rw,
485 sector_t bi_sector, sector_t end_sector,
486 bool end, unsigned long duration,
487 struct dm_stats_aux *stats_aux)
488{
489 sector_t rel_sector, offset, todo, fragment_len;
490 size_t entry;
491
492 if (end_sector <= s->start || bi_sector >= s->end)
493 return;
494 if (unlikely(bi_sector < s->start)) {
495 rel_sector = 0;
496 todo = end_sector - s->start;
497 } else {
498 rel_sector = bi_sector - s->start;
499 todo = end_sector - bi_sector;
500 }
501 if (unlikely(end_sector > s->end))
502 todo -= (end_sector - s->end);
503
504 offset = dm_sector_div64(rel_sector, s->step);
505 entry = rel_sector;
506 do {
507 if (WARN_ON_ONCE(entry >= s->n_entries)) {
508 DMCRIT("Invalid area access in region id %d", s->id);
509 return;
510 }
511 fragment_len = todo;
512 if (fragment_len > s->step - offset)
513 fragment_len = s->step - offset;
514 dm_stat_for_entry(s, entry, bi_rw, fragment_len,
515 stats_aux->merged, end, duration);
516 todo -= fragment_len;
517 entry++;
518 offset = 0;
519 } while (unlikely(todo != 0));
520}
521
522void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
523 sector_t bi_sector, unsigned bi_sectors, bool end,
524 unsigned long duration, struct dm_stats_aux *stats_aux)
525{
526 struct dm_stat *s;
527 sector_t end_sector;
528 struct dm_stats_last_position *last;
529
530 if (unlikely(!bi_sectors))
531 return;
532
533 end_sector = bi_sector + bi_sectors;
534
535 if (!end) {
536 /*
537 * A race condition can at worst result in the merged flag being
538 * misrepresented, so we don't have to disable preemption here.
539 */
540 last = __this_cpu_ptr(stats->last);
541 stats_aux->merged =
542 (bi_sector == (ACCESS_ONCE(last->last_sector) &&
543 ((bi_rw & (REQ_WRITE | REQ_DISCARD)) ==
544 (ACCESS_ONCE(last->last_rw) & (REQ_WRITE | REQ_DISCARD)))
545 ));
546 ACCESS_ONCE(last->last_sector) = end_sector;
547 ACCESS_ONCE(last->last_rw) = bi_rw;
548 }
549
550 rcu_read_lock();
551
552 list_for_each_entry_rcu(s, &stats->list, list_entry)
553 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration, stats_aux);
554
555 rcu_read_unlock();
556}
557
558static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
559 struct dm_stat *s, size_t x)
560{
561 int cpu;
562 struct dm_stat_percpu *p;
563
564 local_irq_disable();
565 p = &s->stat_percpu[smp_processor_id()][x];
566 dm_stat_round(shared, p);
567 local_irq_enable();
568
569 memset(&shared->tmp, 0, sizeof(shared->tmp));
570 for_each_possible_cpu(cpu) {
571 p = &s->stat_percpu[cpu][x];
572 shared->tmp.sectors[READ] += ACCESS_ONCE(p->sectors[READ]);
573 shared->tmp.sectors[WRITE] += ACCESS_ONCE(p->sectors[WRITE]);
574 shared->tmp.ios[READ] += ACCESS_ONCE(p->ios[READ]);
575 shared->tmp.ios[WRITE] += ACCESS_ONCE(p->ios[WRITE]);
576 shared->tmp.merges[READ] += ACCESS_ONCE(p->merges[READ]);
577 shared->tmp.merges[WRITE] += ACCESS_ONCE(p->merges[WRITE]);
578 shared->tmp.ticks[READ] += ACCESS_ONCE(p->ticks[READ]);
579 shared->tmp.ticks[WRITE] += ACCESS_ONCE(p->ticks[WRITE]);
580 shared->tmp.io_ticks[READ] += ACCESS_ONCE(p->io_ticks[READ]);
581 shared->tmp.io_ticks[WRITE] += ACCESS_ONCE(p->io_ticks[WRITE]);
582 shared->tmp.io_ticks_total += ACCESS_ONCE(p->io_ticks_total);
583 shared->tmp.time_in_queue += ACCESS_ONCE(p->time_in_queue);
584 }
585}
586
587static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
588 bool init_tmp_percpu_totals)
589{
590 size_t x;
591 struct dm_stat_shared *shared;
592 struct dm_stat_percpu *p;
593
594 for (x = idx_start; x < idx_end; x++) {
595 shared = &s->stat_shared[x];
596 if (init_tmp_percpu_totals)
597 __dm_stat_init_temporary_percpu_totals(shared, s, x);
598 local_irq_disable();
599 p = &s->stat_percpu[smp_processor_id()][x];
600 p->sectors[READ] -= shared->tmp.sectors[READ];
601 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
602 p->ios[READ] -= shared->tmp.ios[READ];
603 p->ios[WRITE] -= shared->tmp.ios[WRITE];
604 p->merges[READ] -= shared->tmp.merges[READ];
605 p->merges[WRITE] -= shared->tmp.merges[WRITE];
606 p->ticks[READ] -= shared->tmp.ticks[READ];
607 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
608 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
609 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
610 p->io_ticks_total -= shared->tmp.io_ticks_total;
611 p->time_in_queue -= shared->tmp.time_in_queue;
612 local_irq_enable();
613 }
614}
615
616static int dm_stats_clear(struct dm_stats *stats, int id)
617{
618 struct dm_stat *s;
619
620 mutex_lock(&stats->mutex);
621
622 s = __dm_stats_find(stats, id);
623 if (!s) {
624 mutex_unlock(&stats->mutex);
625 return -ENOENT;
626 }
627
628 __dm_stat_clear(s, 0, s->n_entries, true);
629
630 mutex_unlock(&stats->mutex);
631
632 return 1;
633}
634
635/*
636 * This is like jiffies_to_msec, but works for 64-bit values.
637 */
638static unsigned long long dm_jiffies_to_msec64(unsigned long long j)
639{
640 unsigned long long result = 0;
641 unsigned mult;
642
643 if (j)
644 result = jiffies_to_msecs(j & 0x3fffff);
645 if (j >= 1 << 22) {
646 mult = jiffies_to_msecs(1 << 22);
647 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
648 }
649 if (j >= 1ULL << 44)
650 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
651
652 return result;
653}
654
655static int dm_stats_print(struct dm_stats *stats, int id,
656 size_t idx_start, size_t idx_len,
657 bool clear, char *result, unsigned maxlen)
658{
659 unsigned sz = 0;
660 struct dm_stat *s;
661 size_t x;
662 sector_t start, end, step;
663 size_t idx_end;
664 struct dm_stat_shared *shared;
665
666 /*
667 * Output format:
668 * <start_sector>+<length> counters
669 */
670
671 mutex_lock(&stats->mutex);
672
673 s = __dm_stats_find(stats, id);
674 if (!s) {
675 mutex_unlock(&stats->mutex);
676 return -ENOENT;
677 }
678
679 idx_end = idx_start + idx_len;
680 if (idx_end < idx_start ||
681 idx_end > s->n_entries)
682 idx_end = s->n_entries;
683
684 if (idx_start > idx_end)
685 idx_start = idx_end;
686
687 step = s->step;
688 start = s->start + (step * idx_start);
689
690 for (x = idx_start; x < idx_end; x++, start = end) {
691 shared = &s->stat_shared[x];
692 end = start + step;
693 if (unlikely(end > s->end))
694 end = s->end;
695
696 __dm_stat_init_temporary_percpu_totals(shared, s, x);
697
698 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu\n",
699 (unsigned long long)start,
700 (unsigned long long)step,
701 shared->tmp.ios[READ],
702 shared->tmp.merges[READ],
703 shared->tmp.sectors[READ],
704 dm_jiffies_to_msec64(shared->tmp.ticks[READ]),
705 shared->tmp.ios[WRITE],
706 shared->tmp.merges[WRITE],
707 shared->tmp.sectors[WRITE],
708 dm_jiffies_to_msec64(shared->tmp.ticks[WRITE]),
709 dm_stat_in_flight(shared),
710 dm_jiffies_to_msec64(shared->tmp.io_ticks_total),
711 dm_jiffies_to_msec64(shared->tmp.time_in_queue),
712 dm_jiffies_to_msec64(shared->tmp.io_ticks[READ]),
713 dm_jiffies_to_msec64(shared->tmp.io_ticks[WRITE]));
714
715 if (unlikely(sz + 1 >= maxlen))
716 goto buffer_overflow;
717 }
718
719 if (clear)
720 __dm_stat_clear(s, idx_start, idx_end, false);
721
722buffer_overflow:
723 mutex_unlock(&stats->mutex);
724
725 return 1;
726}
727
728static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
729{
730 struct dm_stat *s;
731 const char *new_aux_data;
732
733 mutex_lock(&stats->mutex);
734
735 s = __dm_stats_find(stats, id);
736 if (!s) {
737 mutex_unlock(&stats->mutex);
738 return -ENOENT;
739 }
740
741 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
742 if (!new_aux_data) {
743 mutex_unlock(&stats->mutex);
744 return -ENOMEM;
745 }
746
747 kfree(s->aux_data);
748 s->aux_data = new_aux_data;
749
750 mutex_unlock(&stats->mutex);
751
752 return 0;
753}
754
755static int message_stats_create(struct mapped_device *md,
756 unsigned argc, char **argv,
757 char *result, unsigned maxlen)
758{
759 int id;
760 char dummy;
761 unsigned long long start, end, len, step;
762 unsigned divisor;
763 const char *program_id, *aux_data;
764
765 /*
766 * Input format:
767 * <range> <step> [<program_id> [<aux_data>]]
768 */
769
770 if (argc < 3 || argc > 5)
771 return -EINVAL;
772
773 if (!strcmp(argv[1], "-")) {
774 start = 0;
775 len = dm_get_size(md);
776 if (!len)
777 len = 1;
778 } else if (sscanf(argv[1], "%llu+%llu%c", &start, &len, &dummy) != 2 ||
779 start != (sector_t)start || len != (sector_t)len)
780 return -EINVAL;
781
782 end = start + len;
783 if (start >= end)
784 return -EINVAL;
785
786 if (sscanf(argv[2], "/%u%c", &divisor, &dummy) == 1) {
787 step = end - start;
788 if (do_div(step, divisor))
789 step++;
790 if (!step)
791 step = 1;
792 } else if (sscanf(argv[2], "%llu%c", &step, &dummy) != 1 ||
793 step != (sector_t)step || !step)
794 return -EINVAL;
795
796 program_id = "-";
797 aux_data = "-";
798
799 if (argc > 3)
800 program_id = argv[3];
801
802 if (argc > 4)
803 aux_data = argv[4];
804
805 /*
806 * If a buffer overflow happens after we created the region,
807 * it's too late (the userspace would retry with a larger
808 * buffer, but the region id that caused the overflow is already
809 * leaked). So we must detect buffer overflow in advance.
810 */
811 snprintf(result, maxlen, "%d", INT_MAX);
812 if (dm_message_test_buffer_overflow(result, maxlen))
813 return 1;
814
815 id = dm_stats_create(dm_get_stats(md), start, end, step, program_id, aux_data,
816 dm_internal_suspend, dm_internal_resume, md);
817 if (id < 0)
818 return id;
819
820 snprintf(result, maxlen, "%d", id);
821
822 return 1;
823}
824
825static int message_stats_delete(struct mapped_device *md,
826 unsigned argc, char **argv)
827{
828 int id;
829 char dummy;
830
831 if (argc != 2)
832 return -EINVAL;
833
834 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
835 return -EINVAL;
836
837 return dm_stats_delete(dm_get_stats(md), id);
838}
839
840static int message_stats_clear(struct mapped_device *md,
841 unsigned argc, char **argv)
842{
843 int id;
844 char dummy;
845
846 if (argc != 2)
847 return -EINVAL;
848
849 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
850 return -EINVAL;
851
852 return dm_stats_clear(dm_get_stats(md), id);
853}
854
855static int message_stats_list(struct mapped_device *md,
856 unsigned argc, char **argv,
857 char *result, unsigned maxlen)
858{
859 int r;
860 const char *program = NULL;
861
862 if (argc < 1 || argc > 2)
863 return -EINVAL;
864
865 if (argc > 1) {
866 program = kstrdup(argv[1], GFP_KERNEL);
867 if (!program)
868 return -ENOMEM;
869 }
870
871 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
872
873 kfree(program);
874
875 return r;
876}
877
878static int message_stats_print(struct mapped_device *md,
879 unsigned argc, char **argv, bool clear,
880 char *result, unsigned maxlen)
881{
882 int id;
883 char dummy;
884 unsigned long idx_start = 0, idx_len = ULONG_MAX;
885
886 if (argc != 2 && argc != 4)
887 return -EINVAL;
888
889 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
890 return -EINVAL;
891
892 if (argc > 3) {
893 if (strcmp(argv[2], "-") &&
894 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
895 return -EINVAL;
896 if (strcmp(argv[3], "-") &&
897 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
898 return -EINVAL;
899 }
900
901 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
902 result, maxlen);
903}
904
905static int message_stats_set_aux(struct mapped_device *md,
906 unsigned argc, char **argv)
907{
908 int id;
909 char dummy;
910
911 if (argc != 3)
912 return -EINVAL;
913
914 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
915 return -EINVAL;
916
917 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
918}
919
920int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
921 char *result, unsigned maxlen)
922{
923 int r;
924
925 if (dm_request_based(md)) {
926 DMWARN("Statistics are only supported for bio-based devices");
927 return -EOPNOTSUPP;
928 }
929
930 /* All messages here must start with '@' */
931 if (!strcasecmp(argv[0], "@stats_create"))
932 r = message_stats_create(md, argc, argv, result, maxlen);
933 else if (!strcasecmp(argv[0], "@stats_delete"))
934 r = message_stats_delete(md, argc, argv);
935 else if (!strcasecmp(argv[0], "@stats_clear"))
936 r = message_stats_clear(md, argc, argv);
937 else if (!strcasecmp(argv[0], "@stats_list"))
938 r = message_stats_list(md, argc, argv, result, maxlen);
939 else if (!strcasecmp(argv[0], "@stats_print"))
940 r = message_stats_print(md, argc, argv, false, result, maxlen);
941 else if (!strcasecmp(argv[0], "@stats_print_clear"))
942 r = message_stats_print(md, argc, argv, true, result, maxlen);
943 else if (!strcasecmp(argv[0], "@stats_set_aux"))
944 r = message_stats_set_aux(md, argc, argv);
945 else
946 return 2; /* this wasn't a stats message */
947
948 if (r == -EINVAL)
949 DMWARN("Invalid parameters for message %s", argv[0]);
950
951 return r;
952}
953
954int __init dm_statistics_init(void)
955{
956 dm_stat_need_rcu_barrier = 0;
957 return 0;
958}
959
960void dm_statistics_exit(void)
961{
962 if (dm_stat_need_rcu_barrier)
963 rcu_barrier();
964 if (WARN_ON(shared_memory_amount))
965 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
966}
967
968module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO);
969MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");
generated by cgit v1.2.2 (git 2.25.0) at 2025-01-09 07:20:49 -0500