block/blk-stat.h

#ifndef BLK_STAT_H
#define BLK_STAT_H

/*
 * ~0.13s window as a power-of-2 (2^27 nsecs)
 */
#define BLK_STAT_NSEC		134217728ULL
#define BLK_STAT_NSEC_MASK	~(BLK_STAT_NSEC - 1)

/*
 * Upper 3 bits can be used elsewhere
 */
#define BLK_STAT_RES_BITS	3
#define BLK_STAT_SHIFT		(64 - BLK_STAT_RES_BITS)
#define BLK_STAT_TIME_MASK	((1ULL << BLK_STAT_SHIFT) - 1)
#define BLK_STAT_MASK		~BLK_STAT_TIME_MASK

enum {
	BLK_STAT_READ	= 0,
	BLK_STAT_WRITE,
};

void blk_stat_add(struct blk_rq_stat *, struct request *);
void blk_hctx_stat_get(struct blk_mq_hw_ctx *, struct blk_rq_stat *);
void blk_queue_stat_get(struct request_queue *, struct blk_rq_stat *);
void blk_stat_clear(struct request_queue *);
void blk_stat_init(struct blk_rq_stat *);
bool blk_stat_is_current(struct blk_rq_stat *);
void blk_stat_set_issue_time(struct blk_issue_stat *);
bool blk_stat_enable(struct request_queue *);

static inline u64 __blk_stat_time(u64 time)
{
	return time & BLK_STAT_TIME_MASK;
}

static inline u64 blk_stat_time(struct blk_issue_stat *stat)
{
	return __blk_stat_time(stat->time);
}

#endif