1 /*- 2 * Copyright (c) 2008 Yahoo!, Inc. 3 * All rights reserved. 4 * Written by: John Baldwin <jhb@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the author nor the names of any co-contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * $FreeBSD: src/sys/sys/sglist.h,v 1.2 2009/08/20 19:23:58 jhb Exp $ 31 */ 32 33 /* 34 * A scatter/gather list describes a group of physical address ranges. 35 * Each physical address range consists of a starting address and a 36 * length. 37 */ 38 39 #ifndef __SGLIST_H__ 40 #define __SGLIST_H__ 41 42 #include <sys/refcount.h> 43 44 struct sglist_seg { 45 vm_paddr_t ss_paddr; 46 size_t ss_len; 47 }; 48 49 struct sglist { 50 struct sglist_seg *sg_segs; 51 int sg_refs; 52 u_short sg_nseg; 53 u_short sg_maxseg; 54 }; 55 56 struct mbuf; 57 struct uio; 58 59 static __inline void 60 sglist_init(struct sglist *sg, u_short maxsegs, struct sglist_seg *segs) 61 { 62 63 sg->sg_segs = segs; 64 sg->sg_nseg = 0; 65 sg->sg_maxseg = maxsegs; 66 refcount_init(&sg->sg_refs, 1); 67 } 68 69 static __inline void 70 sglist_reset(struct sglist *sg) 71 { 72 73 sg->sg_nseg = 0; 74 } 75 76 static __inline struct sglist * 77 sglist_hold(struct sglist *sg) 78 { 79 80 refcount_acquire(&sg->sg_refs); 81 return (sg); 82 } 83 84 struct sglist *sglist_alloc(int nsegs, int mflags); 85 int sglist_append(struct sglist *sg, void *buf, size_t len); 86 int sglist_append_mbuf(struct sglist *sg, struct mbuf *m0); 87 int sglist_append_phys(struct sglist *sg, vm_paddr_t paddr, 88 size_t len); 89 int sglist_append_uio(struct sglist *sg, struct uio *uio); 90 int sglist_append_user(struct sglist *sg, void *buf, size_t len, 91 struct thread *td); 92 struct sglist *sglist_build(void *buf, size_t len, int mflags); 93 struct sglist *sglist_clone(struct sglist *sg, int mflags); 94 int sglist_consume_uio(struct sglist *sg, struct uio *uio, size_t resid); 95 int sglist_count(void *buf, size_t len); 96 void sglist_free(struct sglist *sg); 97 int sglist_join(struct sglist *first, struct sglist *second); 98 size_t sglist_length(struct sglist *sg); 99 int sglist_slice(struct sglist *original, struct sglist **slice, 100 size_t offset, size_t length, int mflags); 101 int sglist_split(struct sglist *original, struct sglist **head, 102 size_t length, int mflags); 103 104 #endif /* !__SGLIST_H__ */ 105