1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef DM_STATS_H
3#define DM_STATS_H
4
5#include <linux/types.h>
6#include <linux/mutex.h>
7#include <linux/list.h>
8
9int dm_statistics_init(void);
10void dm_statistics_exit(void);
11
12struct dm_stats {
13 struct mutex mutex;
14 struct list_head list; /* list of struct dm_stat */
15 struct dm_stats_last_position __percpu *last;
16 bool precise_timestamps;
17};
18
19struct dm_stats_aux {
20 bool merged;
21 unsigned long long duration_ns;
22};
23
24int dm_stats_init(struct dm_stats *st);
25void dm_stats_cleanup(struct dm_stats *st);
26
27struct mapped_device;
28
29int dm_stats_message(struct mapped_device *md, unsigned int argc, char **argv,
30 char *result, unsigned int maxlen);
31
32void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
33 sector_t bi_sector, unsigned int bi_sectors, bool end,
34 unsigned long start_time,
35 struct dm_stats_aux *aux);
36
37static inline bool dm_stats_used(struct dm_stats *st)
38{
39 return !list_empty(head: &st->list);
40}
41
42static inline void dm_stats_record_start(struct dm_stats *stats, struct dm_stats_aux *aux)
43{
44 if (unlikely(stats->precise_timestamps))
45 aux->duration_ns = ktime_to_ns(kt: ktime_get());
46}
47
48#endif
49