sglist.h revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2008 Yahoo!, Inc.
5 * All rights reserved.
6 * Written by: John Baldwin <jhb@FreeBSD.org>
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the author nor the names of any co-contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $FreeBSD: stable/11/sys/sys/sglist.h 330897 2018-03-14 03:19:51Z eadler $
33 */
34
35/*
36 * A scatter/gather list describes a group of physical address ranges.
37 * Each physical address range consists of a starting address and a
38 * length.
39 */
40
41#ifndef __SGLIST_H__
42#define	__SGLIST_H__
43
44#include <sys/refcount.h>
45
46struct sglist_seg {
47	vm_paddr_t	ss_paddr;
48	size_t		ss_len;
49};
50
51struct sglist {
52	struct sglist_seg *sg_segs;
53	int		sg_refs;
54	u_short		sg_nseg;
55	u_short		sg_maxseg;
56};
57
58struct bio;
59struct mbuf;
60struct uio;
61
62static __inline void
63sglist_init(struct sglist *sg, u_short maxsegs, struct sglist_seg *segs)
64{
65
66	sg->sg_segs = segs;
67	sg->sg_nseg = 0;
68	sg->sg_maxseg = maxsegs;
69	refcount_init(&sg->sg_refs, 1);
70}
71
72static __inline void
73sglist_reset(struct sglist *sg)
74{
75
76	sg->sg_nseg = 0;
77}
78
79static __inline struct sglist *
80sglist_hold(struct sglist *sg)
81{
82
83	refcount_acquire(&sg->sg_refs);
84	return (sg);
85}
86
87struct sglist *sglist_alloc(int nsegs, int mflags);
88int	sglist_append(struct sglist *sg, void *buf, size_t len);
89int	sglist_append_bio(struct sglist *sg, struct bio *bp);
90int	sglist_append_mbuf(struct sglist *sg, struct mbuf *m0);
91int	sglist_append_phys(struct sglist *sg, vm_paddr_t paddr,
92	    size_t len);
93int	sglist_append_uio(struct sglist *sg, struct uio *uio);
94int	sglist_append_user(struct sglist *sg, void *buf, size_t len,
95	    struct thread *td);
96int	sglist_append_vmpages(struct sglist *sg, vm_page_t *m, size_t pgoff,
97	    size_t len);
98struct sglist *sglist_build(void *buf, size_t len, int mflags);
99struct sglist *sglist_clone(struct sglist *sg, int mflags);
100int	sglist_consume_uio(struct sglist *sg, struct uio *uio, size_t resid);
101int	sglist_count(void *buf, size_t len);
102int	sglist_count_vmpages(vm_page_t *m, size_t pgoff, size_t len);
103void	sglist_free(struct sglist *sg);
104int	sglist_join(struct sglist *first, struct sglist *second);
105size_t	sglist_length(struct sglist *sg);
106int	sglist_slice(struct sglist *original, struct sglist **slice,
107	    size_t offset, size_t length, int mflags);
108int	sglist_split(struct sglist *original, struct sglist **head,
109	    size_t length, int mflags);
110
111#endif	/* !__SGLIST_H__ */
112