/*-
 *
 * XXX: Copyright
 *
 * $FreeBSD$
 */

/*
 * A scatter/gather list describes a group of physical address ranges.
 * Each physical address range consists of a starting address and a
 * length.
 */

#ifndef __SGLIST_H__
#define	__SGLIST_H__

#include <sys/refcount.h>

struct sglist_seg {
	vm_paddr_t	ss_paddr;
	size_t		ss_len;
};

struct sglist {
	struct sglist_seg *sg_segs;
	int		sg_refs;
	u_short		sg_nseg;
	u_short		sg_maxseg;
};

struct mbuf;
struct uio;

#define	SGLIST_INIT(sgl, maxsegs, segs) do {				\
	(sgl)->sg_segs = (segs);					\
	(sgl)->sg_nseg = 0;						\
	(sgl)->sg_maxseg = (maxsegs);					\
	refcount_init(&(sgl)->sg_refs, 1);				\
} while (0)

static __inline void
sglist_reset(struct sglist *sg)
{

	sg->sg_nseg = 0;
}

static __inline struct sglist *
sglist_hold(struct sglist *sg)
{

	refcount_acquire(&sg->sg_refs);
	return (sg);
}

struct sglist *sglist_alloc(int nsegs, int mflags);
int	sglist_append(struct sglist *sg, void *buf, size_t len);
int	sglist_append_mbuf(struct sglist *sg, struct mbuf *m0);
int	sglist_append_phys(struct sglist *sg, vm_paddr_t paddr,
	    size_t len);
int	sglist_append_uio(struct sglist *sg, struct uio *uio);
int	sglist_append_user(struct sglist *sg, void *buf, size_t len,
	    struct thread *td);
struct sglist *sglist_build(void *buf, size_t len, int mflags);
struct sglist *sglist_clone(struct sglist *sg, int mflags);
int	sglist_consume_uio(struct sglist *sg, struct uio *uio, int resid);
int	sglist_count(void *buf, size_t len);
void	sglist_free(struct sglist *sg);
int	sglist_join(struct sglist *first, struct sglist *second);
size_t	sglist_length(struct sglist *sg);
int	sglist_slice(struct sglist *original, struct sglist **slice,
	    size_t offset, size_t length, int mflags);
int	sglist_split(struct sglist *original, struct sglist **head,
	    size_t length, int mflags);

#endif	/* !__SGLIST_H__ */