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 37 static inline bool dm_stats_used(struct dm_stats *st) 38 { 39 return !list_empty(&st->list); 40 } 41 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