dm: bio list helpers

#define DM_BIO_LIST_H

#include <linux/bio.h>

#include <linux/prefetch.h>

struct bio_list {

	struct bio *head;

	struct bio *tail;

};

static inline int bio_list_empty(const struct bio_list *bl)

{

	return bl->head == NULL;

}

#define BIO_LIST_INIT { .head = NULL, .tail = NULL }

#define BIO_LIST(bl) \

	struct bio_list bl = BIO_LIST_INIT

static inline void bio_list_init(struct bio_list *bl)

{

	bl->head = bl->tail = NULL;

}

#define bio_list_for_each(bio, bl) \

	for (bio = (bl)->head; bio && ({ prefetch(bio->bi_next); 1; }); \

	     bio = bio->bi_next)

static inline unsigned bio_list_size(const struct bio_list *bl)

{

	unsigned sz = 0;

	struct bio *bio;

	bio_list_for_each(bio, bl)

		sz++;

	return sz;

}

static inline void bio_list_add(struct bio_list *bl, struct bio *bio)

{

	bio->bi_next = NULL;