freebsd-skq/sys/sys/sglist.h

105 lines
3.4 KiB
C

/*-
* Copyright (c) 2008 Yahoo!, Inc.
* All rights reserved.
* Written by: John Baldwin <jhb@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* 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;
static __inline void
sglist_init(struct sglist *sg, u_short maxsegs, struct sglist_seg *segs)
{
sg->sg_segs = segs;
sg->sg_nseg = 0;
sg->sg_maxseg = maxsegs;
refcount_init(&sg->sg_refs, 1);
}
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, size_t 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__ */