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fuse: allow interrupt queuing without fc->lock
[linux-2.6-block.git] / drivers / md / dm-stats.c
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fd2ed4d2
MP		 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 /*
bbf3f8cb 454 * For strict correctness we should use local_irq_save/restore
fd2ed4d2
MP		 455 * instead of preempt_disable/enable.
456 *
bbf3f8cb
MP		 457 * preempt_disable/enable is racy if the driver finishes bios
458 * from non-interrupt context as well as from interrupt context
459 * or from more different interrupts.
fd2ed4d2 460 *
bbf3f8cb
MP		 461 * On 64-bit architectures the race only results in not counting some
462 * events, so it is acceptable. On 32-bit architectures the race could
463 * cause the counter going off by 2^32, so we need to do proper locking
464 * there.
fd2ed4d2
MP		 465 *
466 * part_stat_lock()/part_stat_unlock() have this race too.
467 */
bbf3f8cb
MP		 468#if BITS_PER_LONG == 32
469 unsigned long flags;
470 local_irq_save(flags);
471#else
fd2ed4d2 472 preempt_disable();
bbf3f8cb 473#endif
fd2ed4d2
MP		 474 p = &s->stat_percpu[smp_processor_id()][entry];
475
476 if (!end) {
477 dm_stat_round(shared, p);
478 atomic_inc(&shared->in_flight[idx]);
479 } else {
480 dm_stat_round(shared, p);
481 atomic_dec(&shared->in_flight[idx]);
482 p->sectors[idx] += len;
483 p->ios[idx] += 1;
484 p->merges[idx] += merged;
485 p->ticks[idx] += duration;
486 }
487
bbf3f8cb
MP		 488#if BITS_PER_LONG == 32
489 local_irq_restore(flags);
490#else
fd2ed4d2 491 preempt_enable();
bbf3f8cb 492#endif
fd2ed4d2
MP		 493}
494
495static void __dm_stat_bio(struct dm_stat *s, unsigned long bi_rw,
496 sector_t bi_sector, sector_t end_sector,
497 bool end, unsigned long duration,
498 struct dm_stats_aux *stats_aux)
499{
500 sector_t rel_sector, offset, todo, fragment_len;
501 size_t entry;
502
503 if (end_sector <= s->start || bi_sector >= s->end)
504 return;
505 if (unlikely(bi_sector < s->start)) {
506 rel_sector = 0;
507 todo = end_sector - s->start;
508 } else {
509 rel_sector = bi_sector - s->start;
510 todo = end_sector - bi_sector;
511 }
512 if (unlikely(end_sector > s->end))
513 todo -= (end_sector - s->end);
514
515 offset = dm_sector_div64(rel_sector, s->step);
516 entry = rel_sector;
517 do {
518 if (WARN_ON_ONCE(entry >= s->n_entries)) {
519 DMCRIT("Invalid area access in region id %d", s->id);
520 return;
521 }
522 fragment_len = todo;
523 if (fragment_len > s->step - offset)
524 fragment_len = s->step - offset;
525 dm_stat_for_entry(s, entry, bi_rw, fragment_len,
526 stats_aux->merged, end, duration);
527 todo -= fragment_len;
528 entry++;
529 offset = 0;
530 } while (unlikely(todo != 0));
531}
532
533void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
534 sector_t bi_sector, unsigned bi_sectors, bool end,
535 unsigned long duration, struct dm_stats_aux *stats_aux)
536{
537 struct dm_stat *s;
538 sector_t end_sector;
539 struct dm_stats_last_position *last;
540
541 if (unlikely(!bi_sectors))
542 return;
543
544 end_sector = bi_sector + bi_sectors;
545
546 if (!end) {
547 /*
548 * A race condition can at worst result in the merged flag being
549 * misrepresented, so we don't have to disable preemption here.
550 */
1f125e76 551 last = raw_cpu_ptr(stats->last);
fd2ed4d2
MP		 552 stats_aux->merged =
553 (bi_sector == (ACCESS_ONCE(last->last_sector) &&
554 ((bi_rw & (REQ_WRITE | REQ_DISCARD)) ==
555 (ACCESS_ONCE(last->last_rw) & (REQ_WRITE | REQ_DISCARD)))
556 ));
557 ACCESS_ONCE(last->last_sector) = end_sector;
558 ACCESS_ONCE(last->last_rw) = bi_rw;
559 }
560
561 rcu_read_lock();
562
563 list_for_each_entry_rcu(s, &stats->list, list_entry)
564 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration, stats_aux);
565
566 rcu_read_unlock();
567}
568
569static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
570 struct dm_stat *s, size_t x)
571{
572 int cpu;
573 struct dm_stat_percpu *p;
574
575 local_irq_disable();
576 p = &s->stat_percpu[smp_processor_id()][x];
577 dm_stat_round(shared, p);
578 local_irq_enable();
579
580 memset(&shared->tmp, 0, sizeof(shared->tmp));
581 for_each_possible_cpu(cpu) {
582 p = &s->stat_percpu[cpu][x];
583 shared->tmp.sectors[READ] += ACCESS_ONCE(p->sectors[READ]);
584 shared->tmp.sectors[WRITE] += ACCESS_ONCE(p->sectors[WRITE]);
585 shared->tmp.ios[READ] += ACCESS_ONCE(p->ios[READ]);
586 shared->tmp.ios[WRITE] += ACCESS_ONCE(p->ios[WRITE]);
587 shared->tmp.merges[READ] += ACCESS_ONCE(p->merges[READ]);
588 shared->tmp.merges[WRITE] += ACCESS_ONCE(p->merges[WRITE]);
589 shared->tmp.ticks[READ] += ACCESS_ONCE(p->ticks[READ]);
590 shared->tmp.ticks[WRITE] += ACCESS_ONCE(p->ticks[WRITE]);
591 shared->tmp.io_ticks[READ] += ACCESS_ONCE(p->io_ticks[READ]);
592 shared->tmp.io_ticks[WRITE] += ACCESS_ONCE(p->io_ticks[WRITE]);
593 shared->tmp.io_ticks_total += ACCESS_ONCE(p->io_ticks_total);
594 shared->tmp.time_in_queue += ACCESS_ONCE(p->time_in_queue);
595 }
596}
597
598static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
599 bool init_tmp_percpu_totals)
600{
601 size_t x;
602 struct dm_stat_shared *shared;
603 struct dm_stat_percpu *p;
604
605 for (x = idx_start; x < idx_end; x++) {
606 shared = &s->stat_shared[x];
607 if (init_tmp_percpu_totals)
608 __dm_stat_init_temporary_percpu_totals(shared, s, x);
609 local_irq_disable();
610 p = &s->stat_percpu[smp_processor_id()][x];
611 p->sectors[READ] -= shared->tmp.sectors[READ];
612 p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
613 p->ios[READ] -= shared->tmp.ios[READ];
614 p->ios[WRITE] -= shared->tmp.ios[WRITE];
615 p->merges[READ] -= shared->tmp.merges[READ];
616 p->merges[WRITE] -= shared->tmp.merges[WRITE];
617 p->ticks[READ] -= shared->tmp.ticks[READ];
618 p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
619 p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
620 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
621 p->io_ticks_total -= shared->tmp.io_ticks_total;
622 p->time_in_queue -= shared->tmp.time_in_queue;
623 local_irq_enable();
624 }
625}
626
627static int dm_stats_clear(struct dm_stats *stats, int id)
628{
629 struct dm_stat *s;
630
631 mutex_lock(&stats->mutex);
632
633 s = __dm_stats_find(stats, id);
634 if (!s) {
635 mutex_unlock(&stats->mutex);
636 return -ENOENT;
637 }
638
639 __dm_stat_clear(s, 0, s->n_entries, true);
640
641 mutex_unlock(&stats->mutex);
642
643 return 1;
644}
645
646/*
647 * This is like jiffies_to_msec, but works for 64-bit values.
648 */
649static unsigned long long dm_jiffies_to_msec64(unsigned long long j)
650{
651 unsigned long long result = 0;
652 unsigned mult;
653
654 if (j)
655 result = jiffies_to_msecs(j & 0x3fffff);
656 if (j >= 1 << 22) {
657 mult = jiffies_to_msecs(1 << 22);
658 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
659 }
660 if (j >= 1ULL << 44)
661 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
662
663 return result;
664}
665
666static int dm_stats_print(struct dm_stats *stats, int id,
667 size_t idx_start, size_t idx_len,
668 bool clear, char *result, unsigned maxlen)
669{
670 unsigned sz = 0;
671 struct dm_stat *s;
672 size_t x;
673 sector_t start, end, step;
674 size_t idx_end;
675 struct dm_stat_shared *shared;
676
677 /*
678 * Output format:
679 * <start_sector>+<length> counters
680 */
681
682 mutex_lock(&stats->mutex);
683
684 s = __dm_stats_find(stats, id);
685 if (!s) {
686 mutex_unlock(&stats->mutex);
687 return -ENOENT;
688 }
689
690 idx_end = idx_start + idx_len;
691 if (idx_end < idx_start ||
692 idx_end > s->n_entries)
693 idx_end = s->n_entries;
694
695 if (idx_start > idx_end)
696 idx_start = idx_end;
697
698 step = s->step;
699 start = s->start + (step * idx_start);
700
701 for (x = idx_start; x < idx_end; x++, start = end) {
702 shared = &s->stat_shared[x];
703 end = start + step;
704 if (unlikely(end > s->end))
705 end = s->end;
706
707 __dm_stat_init_temporary_percpu_totals(shared, s, x);
708
709 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu\n",
710 (unsigned long long)start,
711 (unsigned long long)step,
712 shared->tmp.ios[READ],
713 shared->tmp.merges[READ],
714 shared->tmp.sectors[READ],
715 dm_jiffies_to_msec64(shared->tmp.ticks[READ]),
716 shared->tmp.ios[WRITE],
717 shared->tmp.merges[WRITE],
718 shared->tmp.sectors[WRITE],
719 dm_jiffies_to_msec64(shared->tmp.ticks[WRITE]),
720 dm_stat_in_flight(shared),
721 dm_jiffies_to_msec64(shared->tmp.io_ticks_total),
722 dm_jiffies_to_msec64(shared->tmp.time_in_queue),
723 dm_jiffies_to_msec64(shared->tmp.io_ticks[READ]),
724 dm_jiffies_to_msec64(shared->tmp.io_ticks[WRITE]));
725
726 if (unlikely(sz + 1 >= maxlen))
727 goto buffer_overflow;
728 }
729
730 if (clear)
731 __dm_stat_clear(s, idx_start, idx_end, false);
732
733buffer_overflow:
734 mutex_unlock(&stats->mutex);
735
736 return 1;
737}
738
739static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
740{
741 struct dm_stat *s;
742 const char *new_aux_data;
743
744 mutex_lock(&stats->mutex);
745
746 s = __dm_stats_find(stats, id);
747 if (!s) {
748 mutex_unlock(&stats->mutex);
749 return -ENOENT;
750 }
751
752 new_aux_data = kstrdup(aux_data, GFP_KERNEL);
753 if (!new_aux_data) {
754 mutex_unlock(&stats->mutex);
755 return -ENOMEM;
756 }
757
758 kfree(s->aux_data);
759 s->aux_data = new_aux_data;
760
761 mutex_unlock(&stats->mutex);
762
763 return 0;
764}
765
766static int message_stats_create(struct mapped_device *md,
767 unsigned argc, char **argv,
768 char *result, unsigned maxlen)
769{
770 int id;
771 char dummy;
772 unsigned long long start, end, len, step;
773 unsigned divisor;
774 const char *program_id, *aux_data;
775
776 /*
777 * Input format:
778 * <range> <step> [<program_id> [<aux_data>]]
779 */
780
781 if (argc < 3 || argc > 5)
782 return -EINVAL;
783
784 if (!strcmp(argv[1], "-")) {
785 start = 0;
786 len = dm_get_size(md);
787 if (!len)
788 len = 1;
789 } else if (sscanf(argv[1], "%llu+%llu%c", &start, &len, &dummy) != 2 ||
790 start != (sector_t)start || len != (sector_t)len)
791 return -EINVAL;
792
793 end = start + len;
794 if (start >= end)
795 return -EINVAL;
796
797 if (sscanf(argv[2], "/%u%c", &divisor, &dummy) == 1) {
798 step = end - start;
799 if (do_div(step, divisor))
800 step++;
801 if (!step)
802 step = 1;
803 } else if (sscanf(argv[2], "%llu%c", &step, &dummy) != 1 ||
804 step != (sector_t)step || !step)
805 return -EINVAL;
806
807 program_id = "-";
808 aux_data = "-";
809
810 if (argc > 3)
811 program_id = argv[3];
812
813 if (argc > 4)
814 aux_data = argv[4];
815
816 /*
817 * If a buffer overflow happens after we created the region,
818 * it's too late (the userspace would retry with a larger
819 * buffer, but the region id that caused the overflow is already
820 * leaked). So we must detect buffer overflow in advance.
821 */
822 snprintf(result, maxlen, "%d", INT_MAX);
823 if (dm_message_test_buffer_overflow(result, maxlen))
824 return 1;
825
826 id = dm_stats_create(dm_get_stats(md), start, end, step, program_id, aux_data,
ffcc3936 827 dm_internal_suspend_fast, dm_internal_resume_fast, md);
fd2ed4d2
MP		 828 if (id < 0)
829 return id;
830
831 snprintf(result, maxlen, "%d", id);
832
833 return 1;
834}
835
836static int message_stats_delete(struct mapped_device *md,
837 unsigned argc, char **argv)
838{
839 int id;
840 char dummy;
841
842 if (argc != 2)
843 return -EINVAL;
844
845 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
846 return -EINVAL;
847
848 return dm_stats_delete(dm_get_stats(md), id);
849}
850
851static int message_stats_clear(struct mapped_device *md,
852 unsigned argc, char **argv)
853{
854 int id;
855 char dummy;
856
857 if (argc != 2)
858 return -EINVAL;
859
860 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
861 return -EINVAL;
862
863 return dm_stats_clear(dm_get_stats(md), id);
864}
865
866static int message_stats_list(struct mapped_device *md,
867 unsigned argc, char **argv,
868 char *result, unsigned maxlen)
869{
870 int r;
871 const char *program = NULL;
872
873 if (argc < 1 || argc > 2)
874 return -EINVAL;
875
876 if (argc > 1) {
877 program = kstrdup(argv[1], GFP_KERNEL);
878 if (!program)
879 return -ENOMEM;
880 }
881
882 r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
883
884 kfree(program);
885
886 return r;
887}
888
889static int message_stats_print(struct mapped_device *md,
890 unsigned argc, char **argv, bool clear,
891 char *result, unsigned maxlen)
892{
893 int id;
894 char dummy;
895 unsigned long idx_start = 0, idx_len = ULONG_MAX;
896
897 if (argc != 2 && argc != 4)
898 return -EINVAL;
899
900 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
901 return -EINVAL;
902
903 if (argc > 3) {
904 if (strcmp(argv[2], "-") &&
905 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
906 return -EINVAL;
907 if (strcmp(argv[3], "-") &&
908 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
909 return -EINVAL;
910 }
911
912 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
913 result, maxlen);
914}
915
916static int message_stats_set_aux(struct mapped_device *md,
917 unsigned argc, char **argv)
918{
919 int id;
920 char dummy;
921
922 if (argc != 3)
923 return -EINVAL;
924
925 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
926 return -EINVAL;
927
928 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
929}
930
931int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
932 char *result, unsigned maxlen)
933{
934 int r;
935
936 if (dm_request_based(md)) {
937 DMWARN("Statistics are only supported for bio-based devices");
938 return -EOPNOTSUPP;
939 }
940
941 /* All messages here must start with '@' */
942 if (!strcasecmp(argv[0], "@stats_create"))
943 r = message_stats_create(md, argc, argv, result, maxlen);
944 else if (!strcasecmp(argv[0], "@stats_delete"))
945 r = message_stats_delete(md, argc, argv);
946 else if (!strcasecmp(argv[0], "@stats_clear"))
947 r = message_stats_clear(md, argc, argv);
948 else if (!strcasecmp(argv[0], "@stats_list"))
949 r = message_stats_list(md, argc, argv, result, maxlen);
950 else if (!strcasecmp(argv[0], "@stats_print"))
951 r = message_stats_print(md, argc, argv, false, result, maxlen);
952 else if (!strcasecmp(argv[0], "@stats_print_clear"))
953 r = message_stats_print(md, argc, argv, true, result, maxlen);
954 else if (!strcasecmp(argv[0], "@stats_set_aux"))
955 r = message_stats_set_aux(md, argc, argv);
956 else
957 return 2; /* this wasn't a stats message */
958
959 if (r == -EINVAL)
960 DMWARN("Invalid parameters for message %s", argv[0]);
961
962 return r;
963}
964
965int __init dm_statistics_init(void)
966{
76f5bee5 967 shared_memory_amount = 0;
fd2ed4d2
MP		 968 dm_stat_need_rcu_barrier = 0;
969 return 0;
970}
971
972void dm_statistics_exit(void)
973{
974 if (dm_stat_need_rcu_barrier)
975 rcu_barrier();
976 if (WARN_ON(shared_memory_amount))
977 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
978}
979
980module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO);
981MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");
Linux 6.x block layer and io_uring tree(s)