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 
9 int dm_statistics_init(void);
10 void dm_statistics_exit(void);
11 
12 struct 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 
19 struct dm_stats_aux {
20 	bool merged;
21 	unsigned long long duration_ns;
22 };
23 
24 void dm_stats_init(struct dm_stats *st);
25 void dm_stats_cleanup(struct dm_stats *st);
26 
27 struct mapped_device;
28 
29 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
30 		     char *result, unsigned maxlen);
31 
32 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
33 			 sector_t bi_sector, unsigned bi_sectors, bool end,
34 			 unsigned long start_time,
35 			 struct dm_stats_aux *aux);
36 
dm_stats_used(struct dm_stats * st)37 static inline bool dm_stats_used(struct dm_stats *st)
38 {
39 	return !list_empty(&st->list);
40 }
41 
dm_stats_record_start(struct dm_stats * stats,struct dm_stats_aux * aux)42 static 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(ktime_get());
46 }
47 
48 #endif
49